IEEE BASEPAPER 2017 POWER ELECTRONICS

IEEE BASEPAPER 2017 POWER ELECTRONICS

S.NO TITLE YEAR ABSTRACT

1. A Novel Structure for Single-Switch No isolated Transformer less Buck–Boost DC–DC Converter

2017 With increasing attention to environmental problems, energy achieved from the fuel cell systems is focused on the low environmental effects and clean energy. Fuel cells are an effective alternative to replace fuels in emergency power systems and vehicles. User can use fuel cells as clean energy with low emissions of carbon dioxide. Due to steady operation with renewable fuel supply and high effectiveness and efficiency, the fuel cell has been recognized increasingly as a suitable alternative source. There are some problems of this fuel, such as high costs, but they have brilliant features, such as high efficiency and small size. Due to this explanation, the fuel cell is appropriate as power supplies for telecom back-up facilities and hybrid electric vehicles. The output voltage of the fuel cell unit cell is low and is not steady and it cannot be directly connected to the load. For


applications that need a steady dc voltage, buck–boost dc–dc converter is required.

2. High Light-Load Efficiency Power Conversion Scheme Using Integrated Bidirectional Buck Converter for Paralleled Server Power Supplies

2017 The N power supplies are connected in parallel and provide the output power with an equally shared load current. This increases the power handling capability and the overall efficiency. Additionally, redundant power supplies are normally adopted in this structure. These enable the power to be supplied continuously even when an arbitrary power supply is turned off due to faults, which improves overall reliability. Each power supply has two power conversion stages. The first one is the input filter and the power factor correction (PFC) circuit, which creates low EMI, surge protection, and a high power factor. The PFC circuit, normally using a boost converter, converts the ac voltage to dc link voltage VS of about 400 V. The second power conversion stage is the dc/dc power conversion circuits,


which use an isolation transformer and regulate the output voltage at about 12 V. A phase-shift full-bridge (PSFB) converter is generally used to meet the high step-down voltage, low output voltage, and high output current. In dc/dc power conversion, many components, including many switches and magnetic components, are used, so it is very difficult to improve the overall efficiency, especially under a light-load condition, due to the switching and core losses. Meanwhile, hot-swap circuits using a switch QHS and load-share control circuits are additionally required to connect and drive the paralleled power supplies.

3. High-Voltage Gain Half-Bridge Z-Source Inverter with Low-Voltage Stress on Capacitors

2017 Switched-inductor ZSI has been introduced to obtain high-voltage gains. Its main disadvantage is the increasing capacitors’ voltage stress in comparison with the conventional ZSI and QZSI. In, a new topology called switched-


boost inverter (SBI) has been presented that its disadvantage is lower voltage gain in comparison with the conventional ZSI.

In, a new topology called current-fed switched inverter has been introduced to enhance characteristics of the presented SBI. To overcome the inrush current problems at start up, capacitor voltage stress and obtaining high-voltage gains, a topology called L-ZSI has been presented. Applying Z-source concept into half-bridge converters results in Z-source half-bridge converters.

4. Passivity Enhancement of Grid-Tied Converters by Series LC-Filtered Active Damper

2017 Power electronic converters can widely be found in applications like renewable power generation, power quality conditioning, and AC motor drives. Switching harmonics from these converters are also commonly attenuated by the passive filters, which can either be the simplest L filter or a higher order filter. The latter is


typically dominated by the third-order LCL filter, which presently is recognized to provide better harmonic attenuation even with smaller passive components used. It is, therefore, preferred over the L filter. However, the presence of both L and C components in the filter creates resonances, which can further be influenced by grid inductance (and capacitance even though commonly ignored). Such resonances can be damped by adding either passive or active dampers. Passive dampers are robust, but at the expense of higher losses and sensitivity to component variations. Active dampers are, therefore, preferred in some cases, where they involve changing only the control algorithms of the grid converters. However, improvement by modifying control is not possible if the converter bandwidths are not high enough, which applies to higher rated grid converters. Also, the performance of active


damping is dependent on the system parameter and grid condition.

5. Dual-Bridge LLC Resonant Converter With Fixed-Frequency PWM Control for Wide Input Applications

2017 Power conversion circuits are required to operate with a wide input-voltage range. For example, the output-voltage range of plug-in and battery electric vehicle (EV) on-board chargers is wide (e.g., 200–450 v), which means the input-voltage range of on-board dc/dc converters that condition power between the high- and low-voltage batteries is wide as well.

Therefore, developing a dc/dc converter with high efficiency over a wide voltage range is necessary.LLC resonant converter, which is capable of realizing soft switching from zero to full loads and achieving high efficiency and high power density, has become a research hotspot in recent years. Normally, conventional half- and full-bridge LLC converters work with variable frequency control. The operating frequency range has to be extended or the


inductor ratio has to be decreased in order to obtain a wide input voltage range which is very challenging to design and optimize magnetic components.

6. High-Efficiency Asymmetric Forward-Fly back Converter for Wide Output Power Range

2017 Fly back converter is an isolated step down dc/dc converter that is composed only of one switch, One transformer, and one diode . It has been used widely for an output power po ≤ 100 w because of the simplicity of circuit. However, the fly back converter has low power conversion efficiency ηe at a low po because the switching Frequency increases as po decreases, and its switch is subjected to high-voltage stress because of the leakage inductance llk1 from transformer

7. Interleaved Resonant Boost Inverter Featuring SiC Module for High-Performance Induction Heating

2017 Induction heating (IH) [1] has become a key technology in recent years due to its benefits in terms of performance and efficiency when compared with classical heating methods. Advances in enabling technologies, including power


electronics, digital control, and magnetic components, has enabled a significant breakthrough in IH technology, which has led to a number of relevant industrial [2]–[4], domestic [5]–[7], and medical applications [8].Although alternative implementations using permanent magnets are being studied [9], usually IH systems rely on a power converter to generate an alternating magnetic field to heat the IH target.

8. Unbalanced Control Strategy for A Thyristor-Controlled LC-Coupling Hybrid Active Power Filter in Three-Phase Three-Wire Systems

2017 When unbalanced nonlinear inductive loads are connected to the three-phase utility distribution system, a number of current quality problems, such as low power factor (PF), harmonic pollution, and unbalanced Currents will rise. If compensation is not provided to the distribution power system, it will cause a series of undesirable consequences, such as additional heating and loss in the stator windings, damage on the overloaded phase power


cable, reduction of transmission capability, increase in transmission loss, etc. Implementation of power filters is one of the solutions for power quality problems. In the early days, thyristor-based STATIC VAR COMPENSATORS (SVCS) are used. It can inject or absorb reactive power according to different loading situations. However, SVCS have many inherent problems including resonance problem, slow response, lack of harmonic compensation ability, and self-harmonic generation

9. SL Nonlinear PWM-

Controlled Single-

Phase Boost Mode

Grid-

Connected

Photovoltaic Inverter

With Limited Storage

Inductance Current

A nonlinear pulse width modulation-

controlled single-phase boostmode

photovoltaic grid-connected inverter with

limited storage inductance current is

proposed in this paper. The circuit

topology, control strategy, steady-state

principle characteristic, and design

criterion for the key circuit parameters of

this kind of inverter are investigated in

depth, and important conclusions are

obtained. The inverter’s regenerating

energy duty ratio 1–D which decreases

with the decline of the grid-connected

voltage is real time adapted by sampling

and feeding back the inverting bridge

modulation current, and the average value

of the modulation current in each


switching cycle tracks the reference

sinusoidal signal to get high-quality grid-

connected current. The active control of

the energy storage inductance current and

the balance of the voltage step-up ratio are

realized by adding a bypass switch

connected in parallel with the energy

storage inductance and using two kinds

of switching pattern namely boost pattern

and freewheeling pattern. The theoretical

analysis and experimental results of the 1

Kva 110 VDC/220 V50 Hz photovoltaic

grid-connected inverter prototype show

that it has the advantages such as single-

stage boost conversion, high conversion

efficiency, high quality of grid-connected

current waveform, low value of energy

storage inductance, simple control, etc.

10. SL A Family of Neutral-

Point-Clamped Circuits

of Single-Phase

PV Inverters

The common-mode leakage current

should be carefully considered when

designing a transformer-less

photovoltaic (PV) inverter since the

leakage current can cause the output

current distortion and increase the

operational risk. The unipolar

sinusoidal pulse width modulation of

the traditional H-bridge inverter can

produce the superior output

performance but will cause a high-

frequency fluctuated common-mode

voltage and consequently the

nonnegligible leakage current. To

attenuate the fluctuation phenomena

of common-mode voltage, few

neutralpoint- clamped (NPC) circuits

have been designed to clamp the

neutral-point voltage andmaintain

the common-mode voltage constant.


This paper analyzes the equivalent

common-mode circuit of single-phase

inverters and proposes a generalized

design principle of multiterminal

NPC circuits, whose unidirectional

and bidirectional variations are fully

analyzed. Subsequently, two types

of single-phase PV inverters with the

NPC circuits are proposed. Also, the

operational losses and component

counts are compared between the

proposed topologies and the

traditionalNPC inverters. The

experimental results verified the

theoretical findings.

11. SL A New Six-Switch

Five-Level Active

Neutral Point Clamped

Inverter for PV

Applications

Multilevel inverters are one of the

preferred solutions for medium-

voltage and high-power applications

and have found successful industrial

applications. Five-level active neutral

point clamped inverter (5L-ANPC) is

one of the most popular topologies

among five-level inverters. A six-

switch 5L-ANPC (6S-5L-ANPC)

topology is proposed. Compared to

the conventional 5L-ANPC inverters,

the 6S-5L-ANPC reduces two active

switches and has lower conduction

loss. The proposed modulation

enables the 6S- 5L-ANPC inverter to

operate under both active and

reactive power conditions.The flying-

capacitor capacitance is designed

under both active and reactive power

conditions. The analysis shows the

proposed topology is suitable for

photovoltaic grid-connected


applications. A 1 KVA single-phase

experimental prototype is built to

verify the validity and flexibility of

the proposed topology and

modulation method.

12. SL Single-Stage Three-

Phase Current-Source

Photovoltaic Grid-

Connected Inverter

High Voltage

Transmission Ratio

This paper proposes a circuit

topology of a singlestage three-phase

current-source photovoltaic (PV)

grid-connected inverter with high

voltage transmission ratio (VTR).

Also, an improved zone sinusoidal

pulsewidth modulation (SPWM)

control strategy and an active-

clamped subcircuit that can suppress

the energy storage switch’s turn-off

voltage spike are introduced. The

circuit topology, control strategy,

steady principle characteristics, and

high-frequency switching process are

analyzed profoundly, as well as the

VTR’s expression and design

criterion of the centertapped energy

storage inductor. The improved zone

SPWM control strategy consists of

two control loops, namely, the outer

loop of input dc voltage of PV cells

with the maximum power point

tracking and the inner loop of the

energy storage inductor current. The

experimental results of a 3-kW

96VDC/380V50Hz3ϕAC prototype

have shown that this kind of a three-

phase inverter has the excellent

performances such as single-stage

power conversion, high VTR and

power density, and high conversion

efficiency. Nonetheless, it has small


energy storage inductor and output

CL filter, lo output current total

harmonic distortion, and flexible

voltage configuration of the PV cells.

This study provides an effective

design method for single-stage three-

phase inverting with high VTR.

13. SL A Highly Efficient and

Reliable Inverter

Configuration Based

Cascaded Multilevel

Inverter for PV

Systems

This paper presents an improved

cascaded multilevel inverter (CMLI)

based on a highly efficient and

reliable configuration for the

minimization of the leakage current.

Apart from a reduced switch count,

the proposed scheme has additional

features of low switching and

conduction losses. The proposed

topology with the given pulse width

modulation (PWM) technique

reduces the highfrequency voltage

transitions in the terminal and

commonmode voltages. Avoiding

high-frequency voltage transitions

achieves the minimization of the

leakage current and reduction in the

size of electromagnetic interference

filters. Furthermore, the extension of

the proposed CMLI along with the

PWMtechnique for 2m+ 1 levels is

also presented, wherem represents

the number of photovoltaic (PV)

sources. The proposed PWM

technique requires only a single

carrier wave for all 2m + 1 levels of

operation. The total harmonic

distortion of the grid current for the

proposed CMLI meets the

requirements of IEEE 1547


standard. A comparison of the

proposed CMLI with the existing PV

multilevel inverter topologies is also

presented in the paper. Complete

details of the analysis of PV terminal

and common-mode voltages of the

proposed CMLI using switching

function concept, simulations, and

experimental results are presented in

the paper.

14. SL Modified Single-Phase

Single-Stage Grid-tied

Flying

Inductor Inverter with

MPPT and Suppressed

Leakage

Current

In this paper, an improved

transformer-less single-phase single-

stage grid-tied flying inductor

inverter is presented. The negative

terminal of the PV array is grounded

in the improved topology, which

increases reliability and suppresses

the leakage current. The proposed

topology has buck-boost capability

without increasing the number of

required components and has a high

efficiency. An improved control

algorithm for proper operation of

the proposed topology which

decreases switching losses has been

investigated. Moreover, P&O MPPT

algorithm has been adapted to the

proposed inverter, which doesn’t

utilize PI controllers, for the purpose

of the maximum power point

tracking. Furthermore, design

procedure of the passive elements of

the converter based on the

corresponding operating has been

demonstrated. Simulation in Matlab

Simulink plus an experimental

prototype is developed to reconfirm


the designed results. Finally, a

comparison study has been

investigated for better clarification of

the advantages and disadvantages of

the proposed inverter.

15. SL Reactive Power

Control for Single-

phase Grid-tie Inverters

using Quasi Sinusoidal

Waveform

The paper presents a reactive power

control technique for single-phase

Photovoltaic (PV) inverters,

especially unfolding inverters. The

proposed system retains the benefit

of the unfolding inverters having low

material cost and semiconductor

losses, and tackles the drawback of

the standard unfolding inverter not

having capability of reactive power

injection. It is important to note that

reactive power delivery is mandatory

for PV inverters according to the

recent announced regulations. The

concept is based on changing the

shape of the grid current waveform

but keeping the same zero crossing

points as in the unity power factor

condition. The current waveform is

governed by real power and reactive

power, at the price of an acceptable

deformation. The operating

principles of the proposed technique

and mathematical derivations of the

grid current function are provided in

the paper. Experimental results in a

grid-tie inverter prototype have

shown a good agreement with the

derived theory, and they confirm the

feasibility of using the proposed

technique in grid-tie inverters.

16. SL A Multilevel For the safe operation of


Transformer less

Inverter employing

Ground

Connection between

PV Negative Terminal

and Grid Neutral

point

transformerless grid connected PV

inverters, the issue of common mode

(CM) leakage current needs to be

addressed carefully. In this paper,

a novel multilevel transformerless

inverter topology is proposed which

completely eliminates CM leakage

current by connecting grid neutral

point directly to the PV negative

terminal, thereby bypassing the PV

stray capacitance . Itm provides a

low-cost solution consisting of only

four power switches, two capacitors

and a single filter inductor. As

compared to half bridge topologies,

with this inverter a minimum of 27%

and maximum of 100% more output

voltage is obtained for the same DC

link voltage. The proposed inverter is

analyzed in detail and its switching

pattern to generate multilevel output

while maintaining the capacitor

voltage is discussed. Simulations and

experiments results confirm the

feasibility and good performance of

the proposed inverter.

17. SL An Improved Zero-

Current-Switching

Single-Phase

Transformer less PV

H6 Inverter with

Switching Loss-Free

In this paper, a switching loss-free

(SLF) concept for the first six-

switches H-bridge inverter (H6-I)

topology is proposed. SLF means

that its switches are able to operate

with soft turn-on and turn-off

transitions. In order to implement

the SLF goal, a new resonance-

trajectory is proposed. Compared

with the zero-current-transition H6-I

(ZCT-H6-I) topology published in


previous literature, the proposed

resonance-trajectory can precisely

compensate for losses of resonant

tanks every switching period. With

this intention, an implementing

circuit is structured based on the H6-

I topology, and its detailed operation

principle and performance

characteristics are analyzed. As a

result, all active switches of the new

circuit are switched under zero-

current turn-on and zero-current

turn-off conditions. Also, the reverse

recovery problem of freewheeling

diodes is alleviated owing to the zero-

current turn-off property of diodes.

The SLF target is realized in theory.

Finally, experimental results from a

1 kW prototype at 50 kHz switching

frequency are provided to verify the

effectiveness of the proposed SLF

concept in practice. Specifically, the

conversion efficiency of the new

circuit is over 95% in a wide load

range, and there is roughly a 1.5%

efficiency improvement compared

with the hard-switching H6-I

topology.

18. SL Modulation Technique

for Single-Phase

Transformer less

Photovoltaic Inverters

with Reactive Power

Capability

This paper underpins the principles

for generating reactive power in

single-phase transformerless

photovoltaic (PV) inverters. Two

mainstream and widely adopted PV

inverters are explored, i.e., H5 and

HERIC. With conventional

modulation techniques, reactive


power cannot be realized in H5 and

HERIC due to the absence of

freewheeling path in negative power

region. Based on the study,

modulation techniques are proposed

to provide bidirectional current path

during freewheeling period. With

proposed modulation technique,

reactive power control is achieved in

H5 and HERIC inverters, without

any modification on the converter

structures. The performances of the

proposed modulation techniques are

studied via MATLAB simulation and

further validated with experimental

results.

19. SL Delta Power Control

Strategy for Multistring

Grid-Connected

PV Inverters

With a still increasing penetration

level of gridconnected photovoltaic

(PV) systems, more advanced active

power control functionalities have

been introduced in certain grid

regulations. A delta power

constraint, where a portion of the

active power from the PV panels is

reserved during operation, is

required for grid support (e.g.,

during frequency deviation). In this

paper, a cost-effective solution to

realize delta power control (DPC) for

grid-connected PV systems is

presented, where the multistring PV

inverter configuration is adopted.

This control strategy is a

combination of maximum power

point tracking (MPPT) and constant

power generation (CPG) modes. In

this control scheme, one PV string


operating in the MPPT mode

estimates the available power,

whereas the other PV strings

regulate the total PV power by the

CPG control strategy in such a way

that the delta power constraint for

the entire PV system is achieved.

Simulations and experiments have

been performed on a 3-kW single-

phase gridconnected PV system. The

results have confirmed the

effectiveness of the proposed DPC

strategy, where the power reserve

according to the delta power

constraint is achieved under several

operating conditions.

20. SL Design of Cuk-Derived

Transformer less

Common-Grounded

PV Micro inverter in

CCM

Photovoltaic (PV) microinverters

dispense with the line frequency

transformer, however at the cost of

system grounding and ground

leakage current problems. These

have been erstwhile resolved by the

topologies derived from buck, boost,

buck–boost, Zeta, Watkins–

Johnson, and C´ uk converters, or

combinations of these. The C´ uk

derived inverters, employing second-

order input and output filters, offer

the most efficient, lightweight, and

economical solution in the class. This

paper presents design and detailed

operation of a C´ uk derived,

commonground PV microinverter in

continuous conduction mode

operation. The inverter is shown to

be compatible with both linear and

nonlinear loads, in stand-alone and


gridconnected modes of operation.

Optimal design rules of passive

components are rigorously derived to

ensure attenuation of input voltage

ripples arising from the twin effects

of switching and double-frequency

output power oscillation.

Additionally, the design rules also

incorporate considerations of

efficiency maximization and some

aspects of easing control complexity.

Inverter performance is

experimentally validated with a 300

VA, 110 V, and 50/60 Hz laboratory

prototype

21. SL A Single-Phase

Transformer less

Inverter With Charge

Pump

Circuit Concept for

Grid-Tied PV

Applications

This paper proposes a new single-

phase transformerless photovoltaic

(PV) inverter for grid-tied PV

systems. The topology is derived

from the concept of a charge pump

circuit in order to eliminate the

leakage current. It is composed of

four power switches, two diodes, two

capacitors, and an LCL output filter.

The neutral of the grid is directly

connected to the negative polarity of

the PV panel that creates a constant

common mode voltage and zero

leakage current. The charge pump

circuit generates the negative output

voltage of the proposed inverter

during the negative cycle. A

proportional resonant control

strategy is used to control the

injected current. The main benefits

of the proposed inverter are: 1) the

neutral of the grid is directly


connected to the negative terminal of

the PV panel, so the leakage current

is eliminated; 2) its compact size; 3)

low cost; 4) the used dc voltage of the

proposed inverter is the same as the

full-bridge inverter (unlike neutral

point clamped (NPC), active NPC,

and half-bridge inverters); 5) flexible

grounding configuration; 6)

capability of reactive power flow;

and 7) high efficiency. A complete

description of the operating principle

and analysis of the proposed inverter

are presented. Experimental results

are presented to confirm both the

theoretical analysis and the concept

of the proposed inverter. The

obtained results clearly validate the

performance of the proposed

inverter and its practical application

in grid-tied PV systems.

22. SL A Novel Single-Stage

Single-Phase

Reconfigurable

Inverter

Topology for a Solar

Powered Hybrid

AC/DC Home

This paper suggests a reconfigurable

singlephase inverter topology for a

hybrid ac/dc solar powered home.

This inverter possesses a single-phase

single-stage topology and the main

advantage of this converter is that it

can perform dc/dc, dc/ac, and grid

tie operation, thus reducing loss,

cost, and size of the converter. This

hybrid ac/dc home has both ac and

dc appliances. This type of home

helps to reduce the power loss by

avoiding unnecessary double stages

of power conversion and improves

the harmonic profile by isolating dc

loads to dc supply side and rest to ac


side. Simulation is done in

MATLAB/Simulink and the

obtained results are validated

through hardware implementation

using Arduino Uno controller. Such

type of solar powered home

equipped with this novel inverter

topology could become a basic

building block for future energy

efficient smart grid and microgrid.

23. WND A Medium-Frequency

Transformer-Based

Wind Energy

Conversion System

Used for Current-

Source Converter-

Based Offshore Wind

Farm

Offshore wind farms with series-

interconnected structures are

promising configurations because

bulky and costly offshore substations

can be eliminated. In this paper, a

mediumfrequency transformer

(MFT)-based wind energy

conversion system is proposed for

such wind farms based on current

source converters. The presented

configuration consists of a

mediumvoltage permanent magnet

synchronous generator that is

connected to a low-cost passive

rectifier, an MFT-based cascaded

converter, and an onshore current

source inverter. Apart from fulfilling

traditional control objectives

(maximum power point tracking, dc-

link current control, and reactive

power regulation), this study

endeavors to ensure evenly

distributed power and voltage

sharing among the constituent

modules given the cascaded structure

of the MFT-based converter. In

addition, this paper thoroughly


discusses the characteristic of

decoupling between the

voltage/power balancing of the

modular converter and the other

control objectives. Finally, both

simulation and experimental results

are provided to reflect the

performance of the proposed system.

24. WND Replacing the Grid

Interface Transformer

in Wind Energy

Conversion System

With Solid-State

Transformer

In wind energy conversion systems,

the fundamental frequency step-up

transformer acts as a key interface

between the wind turbine and the

grid. Recently, there have been

efforts to replace this transformer by

an advanced power-electronics-based

solid-state transformer (SST). This

paper proposes a configuration that

combines the doubly fed induction

generator-based wind turbine and

SST operation. The main objective of

the proposed configuration is to

interface the turbine with the grid

while providing enhanced operation

and performance. In this paper, SST

controls the active power to/from the

rotor side converter, thus,

eliminating the grid side converter.

The proposed system meets the

recent grid code requirements of

wind turbine operation under fault

conditions. Additionally, it has the

ability to supply reactive power to

the grid when the wind generation is

not up to its rated value. A detailed

simulation study is conducted to

validate the performance of the

proposed configuration.


25. WND Bipolar Operation

Investigation of

Current Source

Converter-

Based Wind Energy

Conversion Systems

A series-connected current source

converter (CSC)-based configuration

has recently been proposed for

offshore wind energy conversion

systems. A big challenge exists for

such a system that its maximum

insulation level is the full

transmission voltage due to its

monopolar operation. This

introduces significant burden to the

system in terms of cost, reliability,

and flexibility. To solve this issue, a

bipolar operation giving a half

insulation requirement is proposed

and investigated in the present work.

However, a unique challenge exists

for the CSC-based system when

operating under bipolar mode, that

is the dc-link current control. There

are two equivalent paths for the dc-

link current which introduces a

concern for proper operation of the

bipolar system. Accordingly, an

optimized dc-link current control is

developed in this study. In summary,

the bipolar system with the help of

the optimized dc-link current control

features lower insulation

requirement, higher reliability,

higher efficiency, and higher

flexibility. Finally, both simulation

and experimental results are

provided.

26. WND Control Strategy of

Wind Turbine Based

on Permanent

This paper investigates a variable speed

wind turbine based on permanent

magnet synchronous generator and a

full-scale power converter in a stand-


Magnet Synchronous

Generator and Energy

Storage for

Stand-Alone Systems

alone system. An energy storage

system(ESS) including battery and fuel

cell-electrolyzer combination is

connected to the DC link of the full-

scale power converter through the

power electronics interface. Wind is the

primary power source of the system,

the battery and FC-electrolyzer

combination is used as a backup and a

long-term storage system to provide or

absorb power in the stand-alone

system, respectively. In this paper, a

control strategy is proposed for the

operation of this variable speed wind

turbine in a stand-alone system, where

the generator-side converter and the

ESS operate together to meet the

demand of the loads. This control

strategy is competent for supporting the

variation of the loads or wind speed

and limiting the DC-link voltage of the

full-scale power converter in a small

range. A simulation model of a variable

speed wind turbine in a stand-alone

system is developed using the

simulation tool of PSCAD/EMTDC.

The dynamic performance of the stand-

alone wind turbine system and the

proposed control strategy is assessed

and emphasized with the simulation

results.

27. WND

Novel Isolated Power

Conditioning Unit for

Micro Wind

Turbine Application

This paper presents a novel power

conditioning unit (PCU) for variable-

speed micro wind turbine

applications. It contains a simple

generator-side rectifier, galvanic

isolation with a simple dc–dc


converter, and a single-phase full-

bridge inverter at the grid side.

Variable speed micro wind turbines

based on a permanent magnet

synchronous generator (PMSG) are

increasingly used in residential and

small commercial buildings, despite

their relatively low output voltage.

Therefore, they can be used easily

for battery charging, while their grid

integration requires a PCU with

galvanic isolation. Most of available

PCUs provide no galvanic isolation,

or use relatively complicated

topologies or four stage energy

conversion for that purpose. The dc–

dc converter proposed allows

reducing the complexity of the PCU.

Steady-state analysis shows that the

converter is capable of regulating

voltage in a wide range suitable for

micro wind turbines, which is

supported by experimental results

within the input voltage range of

40–400 V. The prototype built for

integration of a 1.3-kW PMSG-based

micro wind turbine shows good

performance over the entire 1:5

range of the given wind turbine

output voltage. A study of efficiency

and power losses was conducted

according to the wind turbine power

profile.

28. MICROGRID Bidirectional Single-

Stage Grid-Connected

Inverter for aBattery

The objective of this paper is to

propose a bidirectional single-stage

grid-connected inverter

(BSGinverter) for the battery energy


Energy Storage System

storage system. The proposed BSG-

inverter is composed of multiple

bidirectional buck–boost type dc–dc

converters (BBCs) and a dc–ac

unfolder. Advantages of the

proposed BSG-inverter include:

single-stage power conversion, low

battery and dc-bus voltages,

pulsating charging/discharging

currents, and individual power

control for each battery module.

Therefore, the equalization, lifetime

extension, and capacity flexibility of

the battery energy storage system

can be achieved. Based on the

developed equations, the power flow

of the battery system can be

controlled without the need of input

current sensor. Also, with the

interleaved operation between BBCs,

the current ripple of the output

inductor can be reduced too. The

computer simulations and hardware

experimental results are shown to

verify the performance of the

proposed BSG-inverter.

29 MICROGRID

Electric Vehicle

Charging Station With

an Energy Storage

Stage for Split-DC Bus

Voltage Balancing

This paper proposes a novel

balancing approach for an electric

vehicle bipolar dc charging station at

the megawatt level, enabled by a

grid-tied neutral-point-clamped

converter. The study uses the

presence of an energy storage stage

with access to both of the dc buses to

perform the complementary balance.

It proposes a generic balancing

structure that can achieve balance


regardless the kind of energy storage

system (ESS) employed. This is

aiming to reduce the hardware

requirements of the system and

maximize the usage of the ESS,

whose main function is to perform

the energy management related

tasks. To meet this purpose, a three-

level dc–dc interface is employed,

allowing to compensate the dc

currents with a single ESS.

Furthermore, in order to prevent the

appearance of even-order harmonics

in the input current during

asymmetrical operation, an

alternative switching sequence for

the central converter is proposed.

Results indicate that, without

altering dramatically the charging

process of the ESS, it is possible to

cover the whole load scenario

without the need of a balancing

circuit. This allows the use of off-the-

shelf products both for the rectifier

and the fast chargers. In this paper,


are presented to validate the

proposed balancing strategy.

30 MICROGRID

A Decentralized

Dynamic Power

Sharing Strategy for

Hybrid

Energy Storage System

in Autonomous DC

Microgrid

Power allocation is a major concern

in hybrid energy storage system.

This paper proposes an extended

droop control (EDC) strategy to

achieve dynamic current sharing

autonomously during sudden load

change and resource variations. The

proposed method consists of a virtual

resistance droop controller and a


virtual capacitance droop controller

for energy storages with

complementary characteristics, such

as battery and supercapacitor (SC).

By using this method, battery

provides consistent power and SC

only compensates high-frequency

fluctuations without the involvement

of conventionally used centralized

controllers. To implement the

proposed EDC method, a detailed

design procedure is proposed to

achieve the control objectives of

stable operation, voltage regulation,

and dynamic current sharing.

System dynamic model and relevant

impedances are derived and detailed

frequency domain analysis is

performed. Moreover, the system

level stability analysis is investigated

and system expansion with the

proposed method is illustrated. Both

simulations and experiments are

conducted to validate the

effectiveness of the proposed control

strategy and analytical results.

31 MICROGRID

Control of a Hybrid

AC/DC Microgrid

Involving Energy

Storage and Pulsed

Load

This paper presents a real-time

coordinated control of the hybrid

ac/dc microgrids involving energy

storage and pulsed loads. Grid-

isolated hybrid microgrid

applications require special

considerations due to the

intermittent generation, online

energy storage control, and pulsed

loads. In this study, we introduce a

comprehensive frequency and


voltage control scheme for a hybrid

ac/dc microgrid consisting of a

synchronous generator, solar

generation emulator, and

bidirectional (ac/dc and dc/dc)

converters. A bidirectional

controlled ac/dc converter with an

active and reactive power decoupling

technique is used to link the ac bus

with the dc bus, while regulating the

system voltage and frequency. A

dc/dc boost converter with a

maximum power point tracking

function is implemented to maximize

the intermittent energy generation

from solar generators. Current-

controlled bidirectional dc/dc

converters are applied to connect

each lithium-ion battery bank to the

dc bus. Lithium-ion battery banks

act as energy storage devices that

serve to increase the system

resiliency by absorbing or injecting

power. Experimental results are

presented for verification of the

introduced hybrid ac/dc power flow

control scheme.

32 MICROGRID

Hybrid Energy Storage

System Micro Grids

Integration For

Power Quality

Improvement Using

Four Leg Three Level

NPC Inverter and

Second Order Sliding

Rising demand for distributed

generation based on Renewable

Energy Sources (RES) has led to

several issues in the operation of

utility grids. The microgrid is a

promising solution to solve these

problems. A dedicated energy

storage system could contribute to a

better integration of RES into the

microgrid by smoothing the


Mode Control

renewable resource’s intermittency,

improving the quality of the injected

power and enabling additional

services like voltage and frequency

regulation. However, due to

energy/power technological

limitations, it is often necessary to

use Hybrid Energy Storage Systems

(HESS). In this paper, a second

order sliding mode controller is

proposed for the power flow control

of a HESS, using aFour Leg Three

Level Neutral Point Clamped (4-Leg

3LNPC) inverter as the only

interface between the RES/HESS

and the microgrid. A three-

dimensional space vector modulation

and a sequence decomposition based

AC side control allows the inverter to

work in unbalanced load conditions

while maintaining a balanced AC

voltage at the point of common

coupling. DC current harmonics

caused by unbalanced load and the

NPC floating middle point voltage,

together with the power division

limits are carefully addressed in this

paper. The effectiveness of the

proposed technique for the HESS

power flow control is compared to a

classical PI control scheme and is

proven through simulations and

experimentally using a 4 Leg 3LNPC

prototype on a test bench.

33 MULTIPORT

Secondary-Side-

Regulated Soft- A systematic method for deriving

soft-switching three-port converters

(TPCs), which can interface multiple


Switching Full-Bridge

Three-Port Converter

Based on Bridgeless

Boost Rectifier

and Bidirectional

Converter for Multiple

Energy Interface

energy, is proposed in this paper.

Novel full-bridge (FB) TPCs

featuring single-stage power

conversion, reduced conduction loss,

and lowvoltage stress are derived.

Two nonisolated bidirectional power

ports and one isolated unidirectional

load port are provided by integrating

an interleaved bidirectional

Buck/Boost converter and a

bridgeless Boost rectifier via a high-

frequency transformer. The

switching bridges on the primary

side are shared; hence, the number

of active switches is reduced.

Primary-side pulse widthmodulation

and secondary-side phase shift

control strategy are employed to

provide two control freedoms.

Voltage and power regulations over

two of the three power ports are

achieved. Furthermore, the

current/voltage ripples on the

primary-side power ports are

reduced due to the interleaving

operation. Zero-voltage switching

and zero-current switching are

realized for the active switches and

diodes, respectively. A typical FB-

TPC with voltage-doubler rectifier

developed by the proposed method is

analyzed in detail. Operation

principles, control strategy, and

characteristics of the FB-TPC are

presented. Experiments have been

carried out to demonstrate the

feasibility and effectiveness of the


proposed topology derivation

method.

34 MULTIPORT Analysis, Design,

Modelling, and Control

of an Interleaved-

Boost Full-Bridge

Three-Port Converter

for Hybrid

Renewable Energy

Systems

This paper presents the design,

modeling, and control of an isolated

dc-dc three-port converter (TPC)

based on an interleaved-boost full-

bridge converter with pulsewidth

modulation (PWM) and phase-shift

control for hybrid renewable energy

systems. In the proposed topology,

the switches are driven by phase-

shifted PWM signals, where both

phase angle and duty cycle are the

controlled variables. The power flow

between the two inputs is controlled

through the duty cycle, whereas the

output voltage can be regulated

effectively through the phase shift.

The primary-side MOSFETs can

achieve zero-voltage-switching (ZVS)

operation without additional

circuitry. Additionally, due to the ac

output inductor, the secondary-side

diodes can operate under zero-

current-switching (ZCS) conditions.

In this study, the operation

principles of the converter are

analyzed and the critical design

considerations are discussed. The

dynamic behavior of the proposed

ac-inductor-based TPC is

investigated by performing state-

space modeling. Moreover, the

derived mathematical models are

validated by simulation and

measurements. In order to verify

the validity of the theoretical


analysis, design, and power

decoupling control scheme, a

prototype is constructed and tested

under the various modes, depending

on the availability of the renewable

energy source and the load

consumption. The experimental

results show that the two decoupled

control variables achieve effective

regulation of the power flow among

the three ports.

35 MULTIPORT Design and

Implementation of an

Amorphous High-

Frequency Transformer

Coupling Multiple

Converters in a

Smart Micro grid

Recent improvements in magnetic

material characteristics and

switching devices have generated

a possibility to replace the electrical

buses with highfrequency magnetic

links in microgrids. Multiwinding

transformers (MWTs) as magnetic

links can effectively reduce the

number of conversion stages of

renewable energy system by

adjusting turn ratio of windings

according to the source voltage level.

Other advantages are galvanic

isolation, bidirectional power flow

capability, and simultaneous power

transfer betweenmultiple ports.

Despite the benefits, design, and

characterization of MWTs are

relatively complex due to their

structural complexity and cross-

coupling effects. This paper presents

all stages of numerical design,

prototyping, and characterization of

an MWT for microgrid application.

To design the transformer for

certain value of parameters, the


reluctance network method is

employed. Due to the iterative nature

of transformer design, it presented

less computation time and

reasonable accuracy. A prototype of

designed transformer is implemented

using amorphous magnetic

materials. A set of experimental tests

are conducted to measure the

magnetic characteristics of the core

and series coupling and open-circuit

tests are applied to measure the

transformer parameters. A

comparison between the simulation

and experimental test results under

different loads within the medium-

frequency range validated both

design and modeling procedures.

36 MULTIPORT Dual-DC-Port

Asymmetrical

Multilevel Inverters

With

Reduced Conversion

Stages and Enhanced

Conversion

Efficiency

A new concept of dual-dc-port

asymmetrical multilevel inverter

(DP-AMI), which is able to interface

a lowvoltage dc port, a high-voltage

dc port, and an ac port

simultaneously using only one

topology, is presented in this paper.

A systematic method to derive the

DP-AMI is proposed. With the

proposed DP-AMI, a low-voltage dc

source, e.g., photovoltaic (PV)

modules or battery, can directly

supply power to the ac load within

single-stage power conversion.

Therefore, in comparison with a

traditional two-stage dc/ac power

conversion system, the power

conversion stages are reduced and

the voltage/current stress of the


frontend dc/dc converter can be

significantly alleviated, which can

improve the overall conversion

efficiency dramatically.

Furthermore, by using the low-

voltage dc source as a new voltage

level, asymmetrical multiple voltage

levels are generated by the proposed

DP-AMI, which is beneficial for the

reducing switching losses and the

size/volume of the output filter. The

topology derivation method of the

DP-AMIs is presented. The

operation principles, modulation

schemes, and characteristics of one

of the proposed DP-AMIs are

analyzed in detail. A 1-kW prototype

is built and tested to verify the

effectiveness and advantages of the

proposed method.

37 MULTIPORT Dual-Transformer-

Based Asymmetrical

Triple-Port Active

Bridge Isolated DC–

DC Converter

In this paper, a dual-transformer-

based asymmetrical triple-port

active bridge converter (DT-ATAB)

is proposed to interface two different

dc-sources and a load. DTATAB

consists of three active power

electronic converters and two high-

frequency transformers. All switches

of these converters can be turned on

with zero-voltage switching to reduce

the switching losses. The

bidirectional power flow operation is

possible between the ports. The DT-

ATAB also reduces the circulating

powers between the ports for

wellmatched transformer turns

ratios as compared to those in the


other existing triple-port active

bridge converters (TAB).

Furthermore, the magnetic short-

circuit conditions arising in the

three-winding transformer of the

TAB are mitigated in DT-ATAB.

The principle of operation, steady-

state analysis, various modes of

operation (three-port and two-port

modes), and a closed loop controller

of DT-ATAB are presented. The

theoretical analysis of this paper is

verified using both simulation and

experimental studies. The illustrated

results show that DT-ATAB can be

used as a promisingmultiport

converter to interface the multiple

sources and load to achieve wide-

ranging outputs with the minimal

losses.

38 INVERTER

A Highly Reliable and

High-Efficiency Quasi

Single-Stage

Buck–Boost Inverter

To regulate an output ac voltage in

inverter systems having wide input

dc voltage variation, a buck–boost

power conditioning system is

preferred. This paper proposes a

novel highefficiency quasi single-

stage single-phase buck–boost

inverter. The proposed inverter can

solve current shoot-through problem

and eliminate PWMdead time, which

leads to greatly enhanced system

reliability. It allows bidirectional

power flow and can use MOSFET

as switching device without body

diode conducting. The reverse

recovery issues and related loss of

the MOSFET body diode can be


eliminated. The use of MOSFET

contributes to the reduction of

switching and conduction losses.

Also, the proposed inverter can be

operated with simple pulse width

modulation (PWM) control and can

be designed at higher switching

frequency to reduce the volume of

passive components. The detailed

experimental results are provided to

show the advantages of the proposed

inverter. Efficiency measurement

shows that using simple PWM

control the proposed inverter can

obtain peak efficiency of 97.8% for

1.1-kW output power at 30-kHz

switching frequency.

39 INVERTER

A Four-Switch Single-

Stage Single-Phase

Buck–Boost

Inverter

This paper proposes a single-phase,

single-stage buck–boost inverter for

photovoltaic (PV) systems. The

presented topology has one common

terminal in input and output

portswhich eliminates common mode

leakage current problem in the

gridconnected PV applications.

Although it uses four switches, its

operation is bimodal and only two

switches receive high-frequency

pulse width modulation signals in

each mode. Its principle of operation

is described in detail with the help of

equivalent circuits. Its

dynamicmodel is presented, based

onwhich a bimodal controller is

designed. Experimental results, in

stand-alone and grid-connected

mode, obtained with a 300-W


laboratory prototype are presented

to validate its performance.

40 INVERTER

Interleaved Resonant

Boost Inverter

Featuring SiC Module

for High Performance

Induction Heating

Induction heating (IH) has become

the technology of choice in many

industrial, domestic, and medical

applications due to its high efficiency

and performance. This paper

proposes an interleaved resonant

boost inverter featuring SiC three-

phase module to achieve high

efficiency and performance IH

power supply. The proposed

converter achieves high efficiency by

reducing the current through the

devices, while the use of an

interleaved full-bridge configuration

reduces input current ripple and

provides additional control degrees.

The proposed converter has been

designed, implemented, and tested

experimentally, proving the

feasibility of this proposal. 41 INVERTER

Modelling and

Optimization of a Zero-

Voltage Switching

Inverter for High

Efficiency and

Miniaturization

In a zero-voltage switching (ZVS)

inverter, high conversion efficiency

andminiaturization are expected

since switching loss can be

dramatically reduced with proper

design. In order to realize ZVS

condition, auxiliary components such

as inductors, capacitors, and

switches are embedded in the

inverter to implement the function.

Since the design of auxiliary

components is critical to the ZVS

inverter, it is impossible to realize

maximum efficiency or minimum

size by following the conventional


design procedure. This paper

introduces an optimized design

methodology for a threephase ZVS

inverter with objectives of both high

efficiency and

miniaturization. Based on the loss

models of different commercial

IGBT modules under different ZVS

conditions, as well as the loss models

of auxiliary components and filter

inductors, the issue of pursuing

highest efficiency and power density

is transformed into solving a

constrained nonlinear multivariable

problem. According to the proposed

design methodology, all parameters

that influence the efficiency and

physical dimensions are considered

simultaneously.Thus, the optimized

selection of the IGBT module, the

parameters of the auxiliary

components and the filter inductors

would be obtained. A 30-kW three-

phase ZVS inverter prototype is built

to verify the proposed design

method. With proposed design

method, the improved prototype has

achieved both smaller passive

components volume and higher

efficiency compared to the former

prototype. 42 INVERTER

Maximum Boost

Control of Diode-

Assisted Buck–Boost

Voltage-Source

Inverter With

Diode-assisted buck–boost voltage-

source inverter machieves high

voltage gain by introducing a switch-

capacitor based high step-up dc–dc

circuit between the dc source and

inverter bridge. As for the unique


Minimum Switching

Frequency

structure, various pulse width

modulation (PWM) strategies are

developed with regard to the

chopped intermediate dc-link

voltage. In order to maximize voltage

gain and increase efficiency, this

paper proposes a novel

PWMstrategy. It regulates the

average value of intermediate dc-link

voltage in one switching time period

(Ts) the same as the instantaneous

maximum value of three-phase line

voltage by controlling the front boost

circuit. Then, the equivalent

switching frequency of power devices

in the inverter bridge can be reduced

to 1/3fs(fs = 1/Ts). The operating

principle and closed-loop controller

design are analyzed and verified by

simulations and experiments.

Compared with existing PWM

strategies, the new control strategy

demonstrates less power device

requirement and higher efficiency in

high voltage gain applications. It is a

more competitive topology for wide

range dc/ac voltage regulation in

renewable energy applications.

Furthermore, with new control

strategy, the dc-side inductor current

and capacitor voltage contains six-

time line-frequency ripples. To

overcome the undesired influence of

low frequency ripples, it is also

suitable for 400–800 Hz medium

frequency aircraft and vessel power

supply system.


43 Multi Level And

Zsource Inverter

A Novel Nine-Level

Inverter Employing

One Voltage Source

and Reduced

Components as High-

Frequency AC Power

Source

Increasing demands for power

supplies have contributed to the

population of high-frequency ac

(HFAC) power distribution system

(PDS), and in order to increase the

power capacity, multilevel inverters

(MLIs) frequently serving as the

high-frequency (HF) source-stage

have obtained a prominent

development. Existing MLIs

commonly use more than one voltage

source or a great number of power

devices to enlarge the level numbers,

and HF modulation (HFM) methods

are usually adopted to decrease the

total harmonic distortion (THD). All

of these have increased the

complexity and decreased the

efficiency for the conversion fromdc

toHF ac. In this paper, a nine-level

inverter employing only one input

source and fewer components is

proposed for HFAC PDS. It makes

full use of the conversion of series

and parallel connections of one

voltage source and two capacitors to

realize nine output levels, thus lower

THD can be obtained without HFM

methods. The voltage stress on power

devices is relatively relieved, which

has broadened its range of

applications as well. Moreover, the

proposed nine-level inverter is

equipped with the inherent self-

voltage balancing ability, thus the

modulation algorithm gets

simplified. The circuit structure,


modulation method, capacitor

calculation, loss analysis, and

performance comparisons are

presented in this paper, and all the

superior performances of the

proposed nine-level inverter are

verified by simulation and

experimental prototypes with rated

output power of 200 W. The

accordance of theoretical analysis,

simulation, and experimental results

confirms the feasibility of proposed

nine-level inverter.

44 Multi Level And

Zsource Inverter

Quasi Cascaded H-

Bridge Five-Level

Boost Inverter

Latterly, multilevel inverters have

become more attractive for

researchers due to low total

harmonic distortion (THD) in the

output voltage and low

electromagnetic interference (EMI).

This paper proposes a novel single-

stage quasi-cascaded H-bridge five-

level boost inverter (qCHB-FLBI).

The proposed five-level inverter has

the advantages over the cascaded H-

bridge quasi-Z-source inverter

(CHB-qZSI) in cutting down passive

components. Consequently, size, cost,

and weight of the proposed inverter

are reduced. Additionally, the

proposed qCHB-FLBI can work in

the shoot-though state. A capacitor

with low voltage rating is added to

the proposed topology to remove an

offset voltage of the output AC

voltage when the input voltages of

two modules are unbalanced.

Besides, a simple PID controller is


used to control the capacitor voltage

of each module. This paper presents

circuit analysis, the operating

principles, and simulation results of

the proposed qCHB-FLBI. A 1.2-

Kva laboratory prototype was

constructed based on a DSP

TMS320F28335 to validate the

operating principle of the proposed

inverter.

45 Multi Level And

Zsource Inverter

Steady-State Analysis

and Design

Considerations of High

Voltage Gain Switched

Z-Source Inverter With

Continuous

Input Current

In this paper, a new topology for Z-

source inverter based on switched Z-

source network is proposed. The

proposed switched Z-source inverter

can provide high voltage gain in low

duty cycles. The continuous input

current is one of the other

advantages of the proposed inverter.

The performance of the proposed

inverter is investigated in different

operating modes and the voltage and

current equations of all elements and

equations of critical inductance are

calculated. Furthermore, the power

losses and efficiency analyses are

presented. The comprehensive

comparison between the proposed

inverter and the other conventional

Z-source inverters shows its excellent

performance. Finally, to prove the

correct operation of the proposed

topology, the experimental and

simulation results using

PSCAD/EMTDC software are

presented.

46 Multi Level And

Zsource Inverter A New Class of Single- In this paper, a class of single-phase

Z-source (ZS) ac-ac converters is


Phase High-Frequency

Isolated ZSource

AC-AC Converters

with Reduced Passive

Components

proposed with high-frequency

transformer (HFT) isolation. The

proposed HFT isolated ZS ac-ac

converters possess all the features of

their non-isolated counterparts, such

as; providing wide range of buck-

boost output voltage with reversing

or maintaining the phase angle,

suppressing the in-rush and

harmonic currents, and improved

reliability. In addition, the proposed

converters incorporate HFT for

electrical isolation and safety, and

therefore can save an external bulky

line frequency transformer, for

applications such as dynamic voltage

restorers (DVRs), etc. The proposed

HFT isolated ZS converters are

obtained from conventional (non-

isolated) ZS ac-ac converters by

adding only one extra bidirectional

switch, and replacing two inductors

with an HFT, thus saving one

magnetic core. The switching signals

for buck and boost modes are

presented with safe-commutation

strategy to remove the switch voltage

spikes. A quasi-Z-source based HFT

isolated ac-ac is used to discuss the

operation principle and circuit

analysis of the proposed class of HFT

isolated ZS ac-ac converters. Various

ZS based HFT isolated proposed ac-

ac converters are also presented

thereafter. Moreover, a laboratory

prototype of the proposed converter

is constructed and experiments are


conducted to produce output voltage

of 110 Vrms/60 Hz, which verify the

operation of the proposed

converters.

47 Multi Level And

Zsource Inverter

Enhanced-Boost Quasi-

Z-Source Inverters

with Two

Switched Impedance

Network

In this paper, two topologies are

presented for the enhanced-boost

quasi-Z-source inverters, namely

continuous input current

configuration and discontinuous

input current configuration of

enhanced-boost quasi-Zsource

inverters with two switched

impedance networks. Similar to

enhanced-boost ZSIs, these proposed

inverter topologies possess very high

boost voltage inversion at low shoot-

through duty ratio and high

modulation index to provide an

improved quality output voltage.

Compared to enhanced-boost ZSIs

with two switched Z-source

impedance networks, these proposed

inverter topologies shares common

ground with source and bridge

inverter, overcomes the starting

inrush problem, draws continuous

input current and the lower voltage

across the capacitors. Moreover, the

input ripple current is negligible.

This paper presents the operating

principles and analysis of continuous

input current configuration

enhanced-boost quasi-Z-source

inverter with two switched

impedance networks and compares

with ZSI, SL-ZSI, DA/CA-qZSI, and

enhanced-boost ZSIs. The theoretical


analysis is done and is validated

through simulation and experimental

results.

48 Multi Level And

Zsource Inverter

High-Voltage Gain

Half-Bridge Z-Source

Inverter With

Low-Voltage Stress on

Capacitors

In this paper, a new topology for

half-bridge Z-source inverter is

proposed. The proposed topology has

only one impedance network. Unlike

to the conventional half-bridge

inverter, the proposed topology can

provide zero voltage level at the

output. It also increases output

voltage level and stabilizes it in the

desired value. Capacitor voltage

stress in the proposed topology is

low, and, therefore, nominal voltage

of capacitor and cost decreases. In

this paper, the steady-state analysis

of the proposed inverter in two new

operations which are named

synchronous operation of diodes and

asynchronous operation of diodes is

conducted based on mathematics

calculations. A method to obtain

high-voltage gains by cascading the

Z-network and combining middle

inductors is presented that leads to

cost, size, and weight reduction.

Comparison among the proposed

converter with conventional ones

shows its excellent performance. The

experimental results have good

agreement with analytical analysis

for the proposed topology.

Drives

A Novel Method of

Reducing

Commutation Torque

In this paper, based on Cuk

converter, a novel commutation

torque ripple reduction strategy is

proposed for the brushless DC


Ripple

for Brushless DC

Motor Based on Cuk

Converter

motor. Output modes (buck–boost

mode and boost mode) of theCuk

converter during the commutation

period and normal conduction

period are altered by designing a

mode selection circuit, which can

reduce commutation torque ripple

over the entire speed range. During

the commutation period, Cuk

converter operates in the boost mode

to step up the input voltage of three-

phase bridge inverter and then meet

the voltage demand of commutation

period, such that the commutation

torque ripple can be reduced by

keeping the noncommutated current

steady. In order to improve the

utilization rate of the converter,

during the normal conduction

period, Cuk converter operates in

the buck–boost mode and the input

voltage of three-phase bridge

inverter is regulated by adopting the

pulse amplitude modulation (PAM)

method without the inverter pulse

width modulation chopping, which

can reduce the voltage spike damage

to the motor windings caused by

turn-on/off ofMOSFETin the

inverter and simplify the program of

modulation method further. The

experimental results verify the

correctness of the theory and the

effectiveness of the proposed

approach.

Drives

Design and

Demonstration of High This paper presents a design

methodology for a high power


Power Density Inverter

for Aircraft

Applications

density converter, which emphasizes

weight minimization. The design

methodology considers various

inverter topologies and

semiconductor devices with

application of cold plate cooling and

LCL filter. Design for a high-power

inverter is evaluated with

demonstration of a 50 kVA 2-level 3-

phase SiC inverter operating at 60

kHz switching frequency. The

prototype achieves high gravimetric

power density of 6.49 kW/kg.

Drives

Commutation Torque

Ripple Reduction in

BLDC Motor

Using Modified SEPIC

converter and three-

level NPC

inverter

This paper presents a new power

converter topology to suppress the

torque ripple due to the phase

current commutation of a brushless

DC motor (BLDCM) drive system. A

combination of a 3-level diode

clamped multilevel inverter (3-level

DCMLI), a modified single-ended

primary-inductor converter

(SEPIC), and a dc-bus voltage

selector circuit are employed in the

proposed torque ripple suppression

circuit. For efficient suppression of

torque pulsation, the dc-bus voltage

selector circuit is used to apply the

regulated dc-bus voltage from the

modified SEPIC converter during

the commutation interval. In order

to further mitigate the torque ripple

pulsation, the 3-level DCMLI is used

in the proposed circuit. Finally,


show that the proposed topology is

an attractive option to reduce the


commutation torque ripple

significantly at low and high speed

applications.

Drives

Quasi-Z-Source

Indirect Matrix

Converter Fed

Induction

Motor Drive for Flow

Control of Dye in

Paper Mill

This paper describes a flow control

of the dye in the paper mill with the

Quasi-Z-Source Indirect Matrix

Converter (QZSIMC) fed induction

motor drive. More than a decade

Voltage Source Inverter (VSI) and

Current Source Inverter (CSI) have

been used to control the speed of the

induction motor which in turns

controls the flow of dye. Recently

Matrix Converter (MC) has been an

excellent competitor for the VSI or

CSI for its compactness. The voltage

transfer ratio of the VSI, CSI and

MC has been limited to 0.866. Thus

the efficiency of these converters is

less. To improve the voltage transfer

ratio the Quasi-Z- Source Network

(QZSN) is to be used between voltage

source and Indirect Matrix

Converter (IMC). Modification in

the shoot through duty ratio of the

QZSN varies the voltage transfer

ratio greater than 0.866. The

different voltage transfer ratio is

needed for different voltage sag

condition. For a variation of the duty

ratio of the QZSN, the fuzzy logic

controller has been presented. To

control the IMC vector control with

Space Vector Modulation (SVM) has

been presented. This paper proposes

the implementation of QZSIMC


adjustable speed drive for flow

control of dye in paper mill during

different voltage sag conditions. A

4kW prototype has been built and

effectiveness of the proposed system

is verified with simulation results

and experimental setup. Simulation

is done in MATLAB, Simulink

platform. Experimental setup is done

with the aid of TMS320F2812 (Texas

Instrument) processor. The

experimental results validate the

maintenance of the speed of

induction motor at set condition,

thus controlling the perfect flow of

dye in paper manufacturing

technology.

Drives

Commutation Torque

Ripple Suppression

Strategy for

Brushless DC Motors

With a Novel Non-

inductive Boost

Front End

This paper firstly presents a novel

boost front end simply with a diode, a

MOSFET and a DC-link capacitor.

Without extra inductors or other power

components, the boost font end could

boost the capacitor voltage with the

motor stator inductances, thus reducing

the influence of the limited DC-link

voltage on commutation torque ripple

reduction to a large extent. A unified

commutation torque ripple suppression

strategy is further proposed with the

front end adopted based on the analysis

about the effects of four switching

vectors on motor speed regulation and

DC-link capacitor voltage regulation.

The proposed strategy can boost the

DC-link capacitor voltage via properly

selection of switching vectors under the

premise of guaranteeing normal speed


regulation in non-commutation period,

and reduce both the commutation

torque ripple and commutation time by

two consistent switching vectors with

the boosted DC-link capacitor voltage

in commutation period. Finally, the

proposed method is theoretically

analyzed with respect to the

capacitance selection and the boot

capacity of NIBFE. The correctness of

the analysis and the effectiveness of the

presented method are validated by the

experimental results.

Wireless Power

Transfer

Z-Source Resonant

Converter With

Constant Frequency

and

Load Regulation for

EV Wireless Charger

Traditional load regulation methods

for a resonant converter mainly rely

on frequency modulation. It is

always a tradeoff between the design

of the resonant network and the

range of load. Especially for wireless

power transfer (WPT) systems, the

resonant network usually has a high

quality factor. Small variation on

frequency leads to huge drop in gain

and efficiency. Due to this problem,

many WPT systems are unregulated

and they need one or two more front-

end stages to regulate the dc bus

voltage and perform power factor

correction (PFC). In order to lower

the cost and complexity of two- or

three-stages structure, a singlestage

solution with a silicon carbide (SiC)

based Z-source resonant converter

(ZSRC) was recently proposed. The

Z-source network provides high

reliability as being immune to shoot-

through problems. Additionally, a


ZSRC can boost the dc bus voltage

while the traditional voltage-source

inverter can only produce a lower

voltage. However, the load regulation

of this new topology has not been

addressed. Two effective load

regulation methods with constant

frequency are presented for this SiC-

based ZSRC specifically. Operation

principle of the two load regulation

methods are described in this paper.

Experimental results based on a 200-

W scale-down prototype with a full-

bridge series resonant dc–dc

converter are presented to illustrate

the mechanism of these two methods.

Wireless Power

Transfer

Bidirectional Current-

Fed Half-Bridge

Configuration for

Inductive Wireless

Power Transfer System

This paper contributes to the analysis

and development of a new power

electronics system for bidirectional

wireless power transfer (WPT). The

major focus is the analysis and

implementation of a new current-fed

resonant topology with currentsharing

and voltage-doubling features. A new

bidirectional WPT system with current-

fed half-bridge voltage-doubler circuit

is proposed and analyzed with series–

parallel and series resonant networks.

Traditionally used parallel L–C

resonant tank in transmitter circuit with

current-fed WPT topology causes

higher voltage stress across the inverter

devices to compensate the reactive

power consumed by the loosely

coupled coil. In the proposed topology,

this is mitigated by adding a suitably

designed capacitor in series with the


transmitter coil; thus, developing a

series–parallel CLC tank. Detailed

analysis and design is reported for both

gridto- vehicle and vehicle-to-grid

operations. The power flow is

controlled through variable frequency

modulation. Soft switching of the

devices is obtained irrespective of the

load current. A proofof- concept

experimental hardware prototype rated

at 1.2 kW is developed and tested.

Experimental results are presented to

verify the analysis and demonstrate the

performance of the system with

bidirectional power flow.

Wireless Power

Transfer

A New Integration

Method for an Electric

Vehicle Wireless

Charging System

Using LCC

Compensation

Topology

There is a need for charging electric

vehicles (EVs) wirelessly since it

provides a more convenient, reliable,

and safer charging option for EV

customers. A wireless charging system

using a double-sided LCC

compensation topology is proven to be

highly efficient; however, the large

volume induced by the compensation

coils is a drawback. In order to make

the system more compact, this paper

proposes a new method to integrate the

compensated coil into the main coil

structure. With the proposed method,

not only is the system more compact,

but also the extra coupling effects

resulting from the integration are either

eliminated or minimized to a negligible

level. Three-dimensional finite-element

analysis tool ANSYS MAXWELL is

employed to optimize the integrated

coils, and detailed design procedures


on improving system efficiency are

also given in this paper. The wireless

charging system with the proposed

integration method is able to transfer

3.0 Kw with 95.5% efficiency (overall

dc to dc) at an air gap of 150 mm.

Wireless Power

Transfer

Higher Order

Compensation for

Inductive-Power-

Transfer

Converters With

Constant-Voltage or

Constant-Current

Output Combating

Transformer Parameter

Constraints

Compensation is crucial for

improving performance of inductive-

power-transfer (IPT) converters.

With proper compensation at some

specific frequencies, an IPT

converter can achieve load-

independent constant output voltage

or current, near zero reactive power,

and soft switching of power switches

simultaneously, resulting in

simplified control circuitry, reduced

component ratings, and improved

power conversion efficiency.

However, constant output voltage or

current depends significantly on

parameters of the transformer,

which is often space constrained,

making the converter design hard to

optimize. To free the design from the

constraints imposed by the

transformer parameters, this paper

proposes a family of higher order

compensation circuits for IPT

converters that achieves any desired

constant-voltage or constant-current

(CC) output with near zero reactive

power and soft switching. Detailed

derivation of the compensation

method is given for the desired

transfer function not constrained by

transformer parameters. Prototypes


of CC IPT configurations based on

a single transformer are constructed

to verify the analysis with three

different output specifications.

Wireless Power

Transfer

Modelling and

Analysis of AC Output

Power Factor for

Wireless Chargers in

Electric Vehicles

This paper presents a general

mathematical expression and

characteristic analysis of the output

power factor before rectification on the

receiver side for wireless chargers in

electric vehicles. This power factor is

usually regarded as unity (i.e., the ac

output voltage is in phase with the

current), based on fundamental

harmonic approximation. However, the

default unity power factor assumption

is not accurate for output power

derivation even at resonance frequency.

This study explores not only output

power factor characteristics for

different frequencies or power levels,

but also the phase relationships of the

input and output ac voltages. The

continuous conduction mode and

discontinuous conduction mode are

both analyzed. An integrated LCC

compensation topology is selected as

the research object, and its analysis

process can be readily extended to

other common topologies.

Furthermore, this study is beneficial for

the implementation of some control

strategies requiring precise power

computation/estimation, e.g.,

feedforward control or model

prediction control. Finally, a

comparison of numerical and

experimental results with various


misalignment cases validates

correctness of the proposed theoretical

derivation and analysis methodology.

Wireless Power

Transfer

Simultaneous Wireless

Power Transfer for

Electric Vehicle

Charging

The major drawback of the battery

charging in traditional electric vehicles

is the use of plug-in charging devices.

The aim of this paper is to propose a

wireless battery charging method, in

addition to power transfer, data related

to battery status, vehicle ID code, or

emergency messages can be

simultaneously transferred between the

grid and vehicle. This work applies

inductive power transfer to complete

the charging system. The proposed

control system can monitor the

operating status on the secondary

(vehicle) side in real time and adjust

charging current depending

on the battery status. Furthermore, the

proposed mechanism is able to make an

immediate stop, if there is any

contingency, such as overcharging

voltage or current. This will be

beneficial to efficient and safety

concern during the charging process. Converters:Buckboost,

Sepic,Flyback,Pushpull

Design and Analysis of

a Class of Zero

Fundamental Ripple

Converters

This paper introduces the design

procedure for a class of bidirectional

zero fundamental ripple or zero first-

order ripple (ZFR) dc–dc converters.

ZFR topologies eliminate the first-

order switching ripples by utilizing a

coupled inductor. As a result, these

converters require smaller inductive

and capacitive filtering elements. After

introducing the modes of operation, the

average model of a ZFR converter is


derived. Using this model, a scheme for

optimal design of the damping circuitry

is introduced. Also, the overall design

procedure for a ZFR converter is

introduced using an example. The

designed ZFR converter is

experimentally evaluated to

demonstrate the effectiveness of the

design procedure. Converters:Buckboost,


Analysis and Design of

Impulse-Commutated

Zero-Current-

Switching Single-

Inductor Current-Fed

Three-Phase Push–

Pull Converter

Impulse commutation obtains zero

current commutation of devices in a

circuit with a short resonance

impulse using a simple resonant

tank. This concept has been studied,

extended, and implemented for a

three-phase push–pull current-fed

singleinductor topology to achieve

soft commutation and device voltage

clamping solving the traditional issue

of device turn-off voltage overshoot.

The push–pull topology is attractive

owing to single inductor, all common

source devices connected to common

supply ground, and reduced gate

driving requirements. Detailed

operation, analysis, and design of

this topology have been reported

with impulse commutation.With a

small resonant tank and partial

resonance, impulse commutation

procures merits of voltage clamping,

low circulating current, and load

adaptive zero-current switching of

the devices. Variable-frequency

modulation regulates load voltage

and maintains the impulse

commutation with source voltage


variation. Experimental results on a

1-kW proof-of-concept hardware

prototype are demonstrated to

observe the operation, performance,

and verify the proposed concept and

claims. Converters:Buckboost,


A Cascaded Coupled

Inductor-Reverse High

Step-Up

Converter Integrating

Three-Winding

Coupled Inductor and

Diode–Capacitor

Technique

This paper introduces a cascaded high

stepup converter realized with a tightly

coupled three-winding coupled

inductor. Compared with existing high

step-up converters, the proposed

converter features that the smaller the

turns ratio, the larger the conversion

gain. So, the name coupled inductor-

reverse is given to represent reverse-

coupled inductor principle of operation.

In addition, diode–capacitor circuit is

introduced to not only recycle leakage

energy to output, but also further lift

voltage conversion gain. This paper

illustrates operation principle of the

proposed converter, discusses effect of

leakage inductance on voltage gain,

and deduces voltage and current

stresses of components. Finally, a

prototype rated at 400 W has been

established, and experimental results

verify correctness of the above

theoretical analysis. Converters:Buckboost,


Passive Regenerative

and Dissipative

Snubber Cells for

Isolated SEPIC

Converters

An isolated converter such as SEPIC

has high voltage stress on the main

switch due to transformer leakage

inductance. To solve this issue active

or passive clamp action is necessary.

The common passive solution based on

an RCD snubber is simple but

impractical when the value of the


leakage inductance is significant. On

the other hand, passive regenerative

solutions generally compromise the

isolation, making the search for a

suitable snubber a challenge. In this

paper, an effective passive regenerative

snubber cell for isolated SEPIC

converters operating in DCM or CCM

is presented. It is intended to improve

the converter efficiency by transferring

the energy stored in the transformer

leakage inductance to the output. The

analysis is presented in detail for DCM

and extended to CCM together with a

practical design procedure. In order to

compare with the RCD, the analysis

and design of a conventional cell are

presented as well. To validate the

proposal and quantify its feasibility,

experimental results are performed for

both dissipative and regenerative

snubbers on a 100 W, 100 V input and

50 V output voltage converter

operating first in DCM and later in

CCM. Converters:Buckboost,


A New Negative

Output Buck-Boost

Converter with Wide

Conversion Ratio

In this paper, a new negative output

(N/O) buck-boost converter, which can

be applied for applications that need

wide range of inverse voltage, is

proposed. The steady state, small signal

model and power losses of the

proposed converter operating in

continuous conduction mode (CCM)

are analyzed. Comparisons among the

traditional buck-boost converter, N/O

hybrid buck-boost converter and N/O

self-lift Luo converter are presented,


and it is found that the proposed

converter possesses a widest voltage

conversion ratio in these four

converters. Finally, a prototype is built,

and the simulated waveforms from the

PSIM software and the experimental

results are presented for validation

High –Voltage

A High-Voltage-Gain

DC–DC Converter

Based on Modified

Dickson Charge Pump

Voltage Multiplier

A high-voltage-gain dc–dc converter is

introduced in this paper. The proposed

converter resembles a two-phase

interleaved boost converter on its input

side while having a Dicksoncharge-

pump-based voltage multiplier (VM)

on its output side. This converter offers

continuous input current, which makes

it more appealing for the integration of

renewable sources like solar panels to a

400-V dc bus. Also, the proposed

converter is capable of drawing power

from either a single source or two

independent sources. Furthermore, the

VM used offers low voltage ratings for

capacitors that potentially leads to size

reduction. The converter design and

component selection have been

discussed in detail with supporting

simulation results. A hardware

prototype of the proposed converter

with Vin = 20 and Vout = 400 V has

been developed to validate the

analytical results.

High –Voltage

Zero-Ripple Input-

Current High-Step-Up

Boost–SEPIC DC–

DC Converter With

Reduced Switch-

This paper proposes a zero-ripple

input-current highstep- up boost–single

ended primary inductor converter

(SEPIC) dc–dc converter with reduced

switch-voltage stress to overcome some

drawbacks of the conventional


Voltage Stress

cascaded boost–SEPIC dc–dc

converter. In the proposed converter,

the input current ripple is significantly

removed by the auxiliary circuit at the

boost stage and the voltage gain is

more increased by using turn ratio of a

coupled inductor at the SEPIC stage.

Additional, the switch-voltage stress

is reduced due to the clamping circuit,

and the reverse-recovery problem of

the output diode is alleviated by the

leakage inductor. Hence, the low-

voltage-rating MOSFET, which has

low Rds(on) , can be utilized as a main

switch device. Therefore, the total

power efficiency is improved. The

theoretical analysis of the proposed

converter is verified on an output 200-

V to 200-W prototype

High –Voltage

Ultra large Gain Step-

Up Coupled-Inductor

DC–DC

In this paper, a novel ultralarge gain

step-up coupled-inductor dc/dc

converter with an asymmetric

voltage multiplier network is

presented for a sustainable energy

system. The proposed converter

contains one boost converter, one

voltage multiplier network, and one

passive lossless clamped circuit. In

order to achieve an ultralarge

voltage gain, one of the two

capacitors is charged by the primary

side and secondary side of the

coupled inductor, then it together

with the secondary side of coupled

inductor provides its energy for the

other capacitor in voltage multiplier

network. Besides, the passive lossless


clamped circuit not only recycles

leakage energy but also effectively

reduces the voltage stress on the

main switch. By this way, the

efficiency of the conversion can be

improved. Moreover, the reverse-

recovery problem of the diodes in the

leakage inductor is alleviated. The

operating principles and steady-state

analyses are illustrated in detail.

Then, the performance of the

proposed converter is compared with

existing converters. Finally, a

prototype circuit at 50-kHz switching

frequency with 20-V input voltage,

200-V output voltage, N = 2, and 200-

W output power is established in the

laboratory to verify the performance

of the proposed converter.

High –Voltage

A High Step-up PWM

DC-DC Converter

With Coupled-

Inductor and Resonant

Switched-Capacitor

In this paper, a novel high step-up

pulse width modulation dc–dc

converter integrating coupled-inductor

and switchedcapacitor (SC) techniques

is presented. The proposed converter

consists of a synchronous rectification

Boost unit and multiple coupled-

inductor-SC units. Its structure can

therefore be easily extended for

ultrahigh voltage gain. The diodes

employed in the proposed converter

can operate under soft-switching

condition by utilizing leakage

inductance of the coupled inductor.

Low-voltagerated transistors can be

used to improve the efficiency as the

voltage stress on the main switches of

the proposed converter is reduced. The


feasibility of the proposed converter is

experimentally demonstrated by a 200

Wprototype converter

High –Voltage

A High-Efficiency

Step-Up Current-Fed

Push–Pull Quasi-

Resonant Converter

With Fewer

Components for Fuel

Cell

Application

In this paper, a new high-efficiency

step-up current-fed push–pull quasi-

resonant converter is proposed,

which is suitable for low-voltage fuel

cell power conditioning system. The

proposed converter conserves

inherent advantages of low-input-

current stress and high voltage

conversion ratio of the conventional

current-fed push–pull converter. All

of power devices can achieve soft

switching at light load improving the

overall efficiency. Moreover, similar

features have been obtained with

fewer components in comparison

with the activeclamped current-fed

push–pull converter [37] and

currentfed push–pull resonant

converter [40], that enabling to

reduce the cost and improve system

reliability. In addition, the voltage-

doubler rectifier is adopted to

eliminate the reverse-recovery

problem of secondary diodes and

provides much higher voltage

conversion ratio resulting in small

turn ratio of the high-frequency

transformer. Detailed operation,

analysis, design, comparative study,

experimental results, and loss

breakdown for the proposed

converter are presented in the paper.

A 510-W prototype verifies the

theoretical analysis and the


effectiveness of the proposed

concept.

Bidirectional

Converter

Cascaded High-

Voltage-Gain

Bidirectional Switched-

Capacitor DC–DC

Converters for

Distributed Energy

Resources Applications

Afamily of bidirectional switched-

capacitor (SC) converters with high-

gain ratio of any positive integer is

proposed in this paper for distributed

energy resources applications. As

compared with other existing SC

converters achieving a same conversion

gain, the main advantages of the

proposed converters are that they

require a relatively lower number of

switches and capacitors, have a

relatively lower switch’s and

capacitor’s stress, and that their

associated driver circuits are simpler to

realize.mImportantly, with the

achievable conversion ratio being

flexible and that the input and output of

the proposed converters are of common

ground, the proposed converters are

widely suitable for many applications.

Moreover, as the proposed converters

do not possess magnetic component or

any component that can severely

degrade the converters’ performance at

high temperature, they are especially

useful for high-temperature

applications. Besides, the proposed

converters are capable of delivering

bidirectional power, which is a key

requirement for emerging applications

with battery storages. Different aspects

of the proposed converters, including

a simple auxiliary power supply circuit

for the MOSFETs’ drivers, will be

discussed in this paper. A nine-time SC


converter prototype that operates with

20-V input voltage, 100-W output, and

at 75 kHz, is constructed and tested.

Experiment results show that the

maximum efficiency achievable with

this prototype is over 98% (without

driver’s loss) and the efficiency over

the entire load range between 25 and

100 W is over 95.5% including the

driver’s loss. The output voltage ripple

of the SC converter is less than 1%.

When the SC converter is open-loop

controlled, the load voltage regulation

is relatively well kept at less than 5%

between full load and no load

conditions.

Bidirectional

Converter

High Light-Load

Efficiency Power

Conversion Scheme

Using Integrated

Bidirectional Buck

Converter for

Paralleled Server

Power Supplies

This paper proposes a new power

conversion scheme for paralleled

server power supplies. The snubber

capacitor voltage is utilized for the

secondary voltage source, from

which bidirectional buck converter

provides output power to the load

under a very light-load condition.

To increase the energy of the

secondary voltage source, an

additional voltage bus is connected

between the snubber capacitors from

each power supply. The main

advantage of the proposed scheme is

that high efficiency can be achieved

especially under a very light-load

condition because of the

lowswitching and core loss achieved

by using the buck converter instead

of the conventional structure

composed of a primary inverter, an


isolation transformer, and a

secondary rectifier. Furthermore,

the buck converter is integrated into

the secondary rectifier circuits, so

additional components are

minimized. The validity of the

proposed converter is confirmed by

the experimental results from two

12-V/750-W prototype modules.

Bidirectional

Converter

Soft switched

Modulation Techniques

for an Isolated

Bidirectional

DC-AC

Two carrier-based unipolar-SPWM-

oriented modulation techniques for an

isolated bi-directional DC-AC

converter are proposed, compared and

validated in this paper. The DC-AC

converter is composed of a full-bridge

(FB) inverter cascaded with a

cycloconverter through a high-

frequency transformer. Both

modulation techniques proposed in this

paper can realize zero-voltage-

switching (ZVS) for the FB inverter

and

zero-current- or zero-voltage-switching

(ZVS/ZCS) for the

cycloconverter in all load range, and

are able to suppress the

voltage spikes introduced by the

transformer leakage inductance

as well. In order to increase the

converter efficiency and power

density, we propose to utilize SiC

MOSFETs for the converter.

The first modulation technique enables

the utilization of Si-SiC

hybrid switches with no synchronous

rectification, for the

purpose of lowering the converter cost.


The second modulation

technique requires all switches to be

SiC MOSFETs, but with

synchronous rectification (SR), which

increases the converter

efficiency. A 400 VDC to 240 VAC,

1.2 kW prototype has been

developed to validate the effectiveness

and performance of the

proposed carrier-based unipolar-

SPWM-oriented modulation

technique

Bidirectional

Converter

A Family of True Zero

Voltage Zero Current

Switching Non

isolated Bidirectional

DC–DC Converter

With Wide Soft

Switching Range

This paper proposes a true zero

voltage zero

current switching (ZVZCS)

nonisolated bidirectional dc–dc

converter with reduced component

count. An auxiliary resonant

network—which comprises of an

inductor, capacitor,

diode, and two switches—provides

the zero voltage switching

transitions of the main switches at

turn on and turn off

instants. In addition, a pair of

auxiliary inductors, which act

as inductive snubbers, aids the zero

current switching transitions.

The proposed configuration is able to

provide soft

commutation for the main switches

for a wide range of input

voltage, switching frequency, and

load current variations—

thus significantly improving the

efficiency profile over a

wide operating window. Besides, the


auxiliary switches are

also soft commutated, while the

reverse recovery loss induced

by the high side diode is eliminated.

The ZVZCS soft

switching operation is demonstrated

by a 150 W prototype

converter; it is proven consistent

with the waveforms derived

from the theoretical analysis. Its

performance is evaluated

against the standard hard-switched

boost, buck, and

several other leading soft switching

converters published

in the recent literature. The

maximum full load efficiency at

100 kHz is recorded at 98.2% and

97.5% in the boost and

buck modes, respectively

Bidirectional

Converter

Modelling and

Analysis of Dual-

Active-Bridge Isolated

Bidirectional DC/DC

Converter to Minimize

RMS Current

with Whole Operating

Range

The triple phase shift (TPS) modulation

scheme, which provides three control

freedoms, is of great importance for the

optimized operation of dual active

bridge (DAB) isolated bidirectional

dc/dc converter. First of all, this paper

introduces an accurate, universal model

to describe the analytic expressions of

the DAB converter under TPS control.

Based on this, six operating modes of

the DAB converter are further

discussed. Afterwards, the concept of

global optimal condition (GOC)

equations is proposed to derive the

closed form of analytic expressions of

an optimal modulation scheme that

makes the DAB converter operate with


minimized root-mean-square (RMS)

current during whole power range with

different operating modes. According

to the GOC equations, the physical

explanation of the proposed modulation

scheme is further given in details, and

the complex interaction among the

control variables, the transferred power

and RMS current are revealed. The

real-time optimization process of the

proposed method is also specified.

Finally, the proposed methods are

applied to a laboratory prototype. The

experimental results confirm the

theoretical analysis and practical

feasibility of the proposed strategies.

Bidirectional

Converter

A Control Map for a

Bidirectional PWM

Plus Phase-Shift-

Modulated Push-Pull

DC-DC Converter

In this paper, a bidirectional push-pull

converter is investigated with new add-

on feature of three-level PWM plus

phase-shift (PPS) control scheme, and a

control map is proposed to assist

converter operation and design in the

optimized region. The PPS control

strategy is adopted to reduce peak

current of the transistors, to increase

the input-voltage-variation range and to

expand the soft-switching region. A

comprehensive analysis of operation

principle, transmission capability and

soft-switching operation in 12 different

operation modes is presented. Based on

the complete analysis, a control map

is proposed to assist converter

operation that can effectively avoid

high-circulating-current regions, low-

power-transmission-capability regions,

and hard-switched regions. In the


control map, a circuit parameter k is

signified and its range is found, beyond

which the PPS converter no longer

operates normally. The proposed

control map and the circuit parameter k

are general to all PPS converters,

providing a meaningful analyzing

method to design and operate all PPS

converters. A 30~48V/380V prototype

rated at 100~1000W was built under

the guideline. The analysis

Bidirectional

Converter

Interleaved Switched-

Capacitor Bidirectional

DC-DC

Converter with Wide

Voltage-Gain Range

for Energy Storage

Systems

In this paper, an interleaved switched-

capacitor bidirectional DC-DC

converter with a high step-up/step-

down voltage gain is proposed. The

interleaved structure is adopted in the

low-voltage side of this converter to

reduce the ripple of the current through

the low-voltage side, and the series-

connected structure is adopted in the

high-voltage side to achieve the high

step-up/step-down voltage gain. In

addition, the bidirectional synchronous

rectification operations are carried out

without requiring any extra hardware,

and the efficiency of the converter is

improved. Furthermore, the operating

principles, voltage and current stresses,

and current ripple characteristics of the

converter are analyzed. Finally, a 1kW

prototype has been developed which

verifies a wide voltage-gain range of

this converter between the variable

low-voltage side (50V-120V)and the

constant high-voltage side (400V). The

maximum efficiency of the converter is

95.21% in the step-up mode and


95.30% in the step-down mode. The

experimental results also validate the

feasibility and the effectiveness of the

proposed topology.

Bidirectional

Converter

A Novel Reversal

Coupled Inductor

High-Conversion-Ratio

Bi-directional DC-DC

Converter

A novel high-conversion-ratio

bidirectional DC-DC converter with

coupled inductor is proposed in this

paper. Compared with the bidirectional

converters based on coupled inductor,

this new topology can realize a higher

step-up voltage gain and lower step-

down voltage gain with a lower turn

ratio in an appropriate duty cycle. In

proposed converter, the windings of the

coupled inductor are reversely

connected to transfer energy from high

voltage source or low voltage source.

Then a clamp capacitor is applied to

reduce voltage stress on main switch,

therefore, the conduction loss of the

main switches can be reduced by using

a low resistance switch, and the clamp

capacitor can also recycle the energy of

the leakage inductor in coupled

inductor. Besides, the soft-switching

technique is used to achieve zero

voltage- switching, so the efficiency

can be further improved. The main

circuit and its steady-state operating

principle are analyzed in detail. Finally,

a 25-200V 200W bidirectional DC-DC

converter is implemented to verify its

performance.

Multiple Output

Converter

Design and

Implementation of a

High-Efficiency

Multiple output converters (MOCs)

are widely applied to applications

requiring various levels of output

voltages due to their advantages in


Multiple

Output Charger Based

on the Time-Division

Multiple Control

Technique

terms of cost, volume, and efficiency.

However, most of the conventional

MOCs cannot regulate multiple

outputs tightly and they can barely

avoid the cross-regulation problem.

In this paper, the recently developed

time-division multiple control

(TDMC) method, which can regulate

all of the outputs with a high

accuracy, is used for a multiple

output battery charger based on the

phase-shift full-bridge topology to

simultaneously charge three

batteries. The proposed charger is

able to charge three different kinds

of batteries or three of the same kind

of battery in different state of

charges (SOCs) independently and

accurately with the constant

current/constant voltage (CC/CV)

charge method. As a result, the strict

ripple specification of a battery can

be satisfied for multiple battery

charges without difficulty. In

addition, the proposed charger

exhibits a high efficiency since the

soft switching of all of the switches

during the entire charge process can

be guaranteed. The operating

principle of the converter and the

design of the controller, including the

state-space average modeling, will be

detailed, and the validity of the

proposed method is verified through

experiments.

Multiple Output

Converter Analysis and Design of

an Input-Series Two- In this paper, an input-series two-

transistor forward converter is


Transistor

Forward Converter for

High-Input Voltage

Multiple-Output

Applications

proposed and investigated, which is

aiming at the high-input voltage

multiple-output applications. In this

converter, all of the switches are

operating synchronously, and the input

voltage sharing (IVS) of each series-

module is achieved automatically by

the coupling of primary windings of the

common forward integrated

transformer. The active IVS processes

are analyzed based on the model of the

forward integrated transformer.

Through the influence analysis when

the mismatches in various series-

modules are considered, design

principles of the key parameters in each

series-module are discussed to suppress

the input voltage difference. Finally, a

96W laboratory-made prototype

composed of two forward series-

modules is built, and the feasibility of

the proposed method and the

theoretical analysis are verified by the


Multiple Output

Converter

A Dual-Buck–Boost

AC/DC Converter for

DC Nanogrid

With Three Terminal

Outputs

Due to the widely used dc

characterized loads and more

distributed power generation

sources, the dc nanogrid becomes

more and more popular, and it is

seen as an alternative to the ac grid.

For safety considerations, the dc

nanogrid should provide reliable

grounding for the residential loads

such as the low-voltage ac power

system. There are three typical

grounding configurations for a dc

nanogrid: the united grounding, the


unidirectional grounding, and the

virtual isolated grounding. Each

grounding configuration has its own

specifications to ac/dc converters.

In this paper, a dual-buck–boost

ac/dc converter for use in the united-

grounding-configuration-based dc

nanogrid with three terminal outputs

is proposed. The working principle

of this converter is presented in

detail through analyzing the

equivalent circuits. Experiments are

carried out to verify the theoretical

analysis.

Multiple Output

Converter

Improved Power

Quality Bridgeless

Converter-Based

SMPS

for Arc Welding

This paper proposes a power-factor-

corrected bridgeless (BL) switched-

mode power supply (SMPS) for

welding applications that possesses

output voltage control and current

limiting feature even during extreme

overloading conditions at the output

terminals. Eliminating an input

diode bridge rectifier minimizes

conduction losses and improves

thermal utilization of semiconductor

devices. The front-end of the

proposed SMPS consists of a BL

boost converter operating in a

continuous conduction mode to

attain unity power factor, while at

the rear end a pulse width

modulation isolated full bridge dc–dc

converter is used to regulate the

output voltage. The design and

implementation of this BL arc

welding power supply (AWPS) is

presented showing its fast dynamic


response to supply voltage and load

variations. The performance of the

proposed AWPS is examined in

terms of power factor, total

harmonic distortion of the supply

current, efficiency, and output

current limit over a wide range of

line/load variations. Test results

confirm the effectiveness of the

proposed AWPS in maintaining an

impeccable power quality at utility

interface apart from achieving an

excellent output voltage regulation

and current limiting capability.

Led Applicatons

An AC–DC LED

Driver With a Two-

Parallel Inverted Buck

Topology for Reducing

the Light Flicker in

Lighting

Applications to Low-

Risk Levels

This paper presents an ac–dcLEDdriver

that consists of two-parallel inverted

buck converters. To buffer the twice-

linefrequency energy, one inverted

buck converter (also known as a

floating buck converter) conveys

energy to a storage capacitor,

simultaneously performing the power

factor correction. The other inverted

buck converter regulates the LED

current to maintain a constant

brightness in theLEDs for reducing the

light flicker to lowrisk levels.The

proposed architecture reduces the

voltage stress and the size of the

storage capacitor, enabling the use of a

film capacitor instead of an electrolytic

capacitor. Considering the power factor

and the flicker standards, a design

procedure to achieve a high power

factor, while minimizing the storage

capacitance and the LED current ripple,

is presented. A prototype of the


proposed LED driver has been

implemented with an on-chip controller

IC fabricated in a 0.35-μm CMOS

process and its functionality and

performance have been verified

experimentally. It demonstrates a

power factor of 0.94 and a peak power

efficiency of 85.4% with an LED

current ripple of 6.5%, while delivering

15 Wto the LEDs.

Led Applicatons

Single-Stage Single-

Switch Four-Output

Resonant LED

Driver With High

Power Factor and

Passive Current

Balancing

A resonant single-stage single-switch

four-output LED driver with high

power factor and passive current

balancing is proposed. By controlling

one output current, the other output

currents of four-output LED driver can

be controlled via passive current

balancing, which makes its control

simple. When magnetizing inductor

current operates in critical conduction

mode, unity power factor is achieved.

The proposed LED driver uses only

one active switch and one magnetic

component, thus it benefits from low

cost, small volume, and light weight.

Moreover, high-efficiency performance

is achieved due to single-stage power

conversion and soft-switching

characteristics. The characteristics of

the proposed LED driver are studied in

this paper and experimental results of

two 110-W four-output isolated LED

drivers are provided to verify the

studied results.

Led Applicatons

Single-Switch

Coupled-Inductor- In this paper, a single-switch coupled-

inductor-based two-channel light-

emitting diode (LED) driver with a


Based Two-Channel

LED

Driver With a Passive

Regenerative Snubber

passive regenerative snubber is

presented. In the proposed LED driver,

the energy-transferring capacitor is not

only used to step up the voltage gain

but also to achieve the current balance

among LED strings. Moreover, a

passive regenerative snubber is added

not only to recycle the leakage

inductance energy but also to improve

the voltage gain. As compared with the

prior work, only one switch is required.

Thus, the configuration of the proposed

LED driver is simpler. Since the

proposed LED driver has a higher

voltage gain than the priorwork, the

turns ratio of the proposed LED driver

can be lower. Thus, the magnetic core

size can be reduced. In addition, both

LED drivers have the same component

count. Finally, the operating principle,

analysis, and experimental results are

provided to verify the effectiveness of

the proposed LED driver.

Led Applicatons

Analysis and Design of

a Single-Stage Isolated

AC–DC LED

Driver With a Voltage

Doubler Rectifier

In order to reduce the cost and volume

of small-medium power ac–dc light-

emitting diode (LED) lighting systems,

single-stage LED drivers are often used

to drive LEDs with constant current. In

this paper, a singlestage isolated high-

power factor ac–dc LED driver is

proposed and analyzed in detail, which

is composed of a buck–boost power

factor correction unit operating in

discontinuous conduction mode and an

isolated dc/dc unit with a voltage

doubler rectifier, and the two units are

integrated together by sharing the same


power switch. Very high input power

factor is achieved since the PFC unit

operates with almost fixed duty ratio

during half period of the utility line

voltage. Since a voltage doubler

rectifier is included in the isolated

dc/dc unit, magnetic core size of the

transformer and voltage stress of the

secondary side diodes are reduced

remarkably. First, the operating

principle and performance of the LED

driver are analyzed. Then, the main

parameters are quantitatively calculated

out in detail. Finally, a comparative

analysis is presented and a 120W

experimental prototype with 1 A output

current is built according to the

calculated parameters and the

experimental results are presented to

verify the correctness of the theoretical

analysis and parameter design.

Led Applicatons

Flyback-Based Three-

Port Topologies for

Electrolytic

Capacitor-Less LED

Drivers

Electrolytic capacitors are the

components that mainly impact the

lifetime of ac/dc light-emitting diode

(LED) drivers. Therefore, eliminating

electrolytic capacitors from LED

drivers is of vital importance. First, the

basic derivation concept of a family of

flyback-based three-port converters for

electrolytic capacitor-less LED drivers

is addressed in this paper, by

manipulating the power flow among

input port, output port, and storage

capacitors. Together with the

derivation of existing topologies, new

topologies are also proposed. After

evaluation, an integrated dual flyback


converter (IDFC) is chosen, which

requires less switching components and

simpler control strategy. Following

that, the operation principle and

switching modes of the IDFC are

elaborated, as well as the parameter

design and implementation of control

strategy. Finally, experiments on a

laboratory prototype are carried out to

verify the feasibility of the proposed

topology

Led Applicatons

A Single-Switch AC–

DC LED Driver Based

on a Boost-

Flyback PFC Converter

With Lossless Snubber

A single-switch ac–dc light-emitting-

diode (LED) driver based on boost-

flyback power factor correction (PFC)

converter with a lossless snubber is

proposed. In the proposed LED driver,

the boost PFC module is designed to be

operated in the discontinuous-

conduction mode to achieve a high

power factor. The dc–dc flyback

module is designed to provide input–

output electrical isolation to improve

safety. The lossless snubber circuit

clamps the peak voltage spike of switch

to a low voltage and the leakage

inductor energy is recycled via the dc–

dc flyback module. Additionally, a

low-voltage-rating capacitor can be

used as the dc-bus capacitor because

some of the input power is directly

conducted to the output; the remaining

power is stored in the dc-bus capacitor.

Therefore, the proposed LED driver

can provide a high power factor and a

high power conversion efficiency.

These results are verified for an output

of 48 V and 2 A for the experimental


prototype.

Power Factor

Correction

Flexible Mode

Bridgeless Boost PFC

Rectifier With High

Efficiency Over a Wide

Range of Input Voltage

For the conventional PFC rectifiers, the

high efficiency cannot be achieved

over a wide input range, and the

efficiency will be greatly decreased at

low-input voltages. In order to

overcome the efficiency bottleneck

under low-line input, a flexible mode

bridgeless boost power factor

correction (PFC) rectifier is proposed

in this paper. According to the input

voltage, the proposed rectifier can be

flexibly adapted to the suitable

operating mode to obtain the maximum

efficiency. Meanwhile, the circuit

components can be reused by different

operating modes, so the extra cost is

low. In the proposed rectifier, a back-

to-back bridgeless boost PFC topology

is adopted at high-line conditions and a

three-level bridgeless boost PFC

topology is rebuilt to reduce the

switching losses at low-line conditions.

Compared with the traditional

bridgeless boost PFC rectifier, an extra

low-voltage bidirectional switch

(usually composed of two switches) is

added, so the increased cost is low. In

addition, the low common-mode noise

can be achieved at both high- and low-

line conditions due to the direct

connection between the input mains

and the output electrolytic capacitor.

The detailed principle analysis about

the proposed rectifier is presented in

this paper. Finally, an experimental

prototype is built to verify the


feasibility and the effectiveness of the

proposed topology.

Power Factor

Correction

A Family of Single-

Phase Voltage-Doubler

High-Power-

Factor SEPIC

Rectifiers Operating in

DCM

This paper extends the voltage-doubler

concept to the single-phase SEPIC

rectifier in discontinuous conduction

mode and, as a consequence, novel

rectifiers are proposed. A comparison

with the classic SEPIC rectifier shows

that the proposed converters can either

provide reduced voltage stress on the

semiconductors for the same output

voltage level or supply double the gain

of the output voltage with the same

voltage stress. The proposed voltage-

doubler SEPIC rectifiers provide a high

power factor with no current control

and they can be applied in order to

improve the static gain of the structure,

which can make the SEPIC rectifier

suitable for applications that require a

high voltage level. In this paper, the

generic structure based on a three-state

switch, four different implementations

of the proposed concept (including

bridgeless structures), steady-state

analysis, a dynamic model, system

control, and experimental results are

presented. The proposed rectifiers were

verified by experimental results

obtainedwith a prototype built with the

following specifications: 1000Woutput

power, 220 V input voltage, 400 V

output voltage, and 50 kHz switching

frequency. Peak efficiency of 95.84%,

THD of 2%, and power factor of

0.9997 were obtained and, most

importantly, double the gain of the


output voltage was verified.

Power Factor

Correction

A Family of Single-

Phase Hybrid Step-

Down PFC

Converters

Buck power factor correction (PFC)

has attracted a lot of research interests

for its low output voltage and high

efficiency at low input condition.

However, the traditional Buck PFC

converter usually has low power factor

(PF) and poor harmonic performance

due to the inherent dead angle of the

input current, especially at low input

condition. To solve this problem, this

paper proposes a family of hybrid PFC

converter topologies combining the

advantages of step-up PFC and step-

down (Buck) PFC converters, which

features low output voltage and

continuous input current (high PF). The

derivation methodology is presented in

detail and two topologies are selected

as typical examples to explore their

performances. With the improved peak

current control scheme, the two

proposed converters can achieve high

PF under universal input range, and

their input current harmonics can easily

meet the IEC61000-3-2 Class C limits.

The optimal design considerations are

presented and two 150–W prototypes

are built to verify the theoretical

analysis.

Power Factor

Correction

A Boost PFC Stage

Utilized as Half-Bridge

Converter for

High-Efficiency DC–

DC Stage in Power

Supply Unit

The half-bridge (HB) LLC converter is

one of the most attractive dc–dc

converters for medium power supplies

due to its soft switching capability.

However, its conversion efficiency is

considerably degraded in wide-link-

voltage applications because of a small


magnetizing inductance and wide

switching frequency variation for a

high voltage gain. In this paper, a boost

power factor correction (PFC) stage,

which can also play an important role

during the hold-up time, is proposed

for a high-efficiency HB LLC

converter. In the proposed PFC stage,

the boost PFC converter can be

effectively utilized as a HB converter

by replacing a boost diode and inductor

with a synchronous switch and

transformer, respectively. After the ac

line is lost, the proposed PFC stage can

operate as the HB converter and

regulate the output voltage instead of

the HB LLC converter. Thus, it enables

the HB LLC converter to be designed

with a large magnetizing inductance

and narrow switching frequency

variation. As a result, the proposed

PFC stage can enhance the overall

efficiency of the PSU by improving the

efficiency of the HB LLC converter.

To confirm the validity of this paper, a

prototype with 180–264-Vrms ac line,

250–400-V link voltage, and 48 V/480

Woutput is tested.

Soft Switching

Converter

A T-Type Isolated Zero

Voltage Switching

DC–DC

Converter With

Capacitive Output

A novel isolated dc–dc converter is

proposed, using the T-Type topology

with zero voltage switching and pulse

width modulated with a capacitive

output filter. It uses four switches, two

of which are subjected to the input

voltage, and the other two to half the

input voltage. All switches commutate

under zero voltage over a wide load


range. The proposed converter has the

following features: (a) symmetrical

operation of the isolation transformer,

(b) modulation by pulse width with

constant frequency, (c) zero voltage

switching, and (d) three-level voltage

applied to the primary winding of the

transformer. Theoretical analysis,

design example, and experimental data

for a 2 kW, 400VDCinput,

400VDCoutput, and 50 kHz switching

frequency laboratory prototype,

working in two operating points are

included in this paper. The measured

efficiency was 95% at 950W.

Soft Switching

Converter

A Hybrid ZVZCS

Dual-Transformer-

Based Full-Bridge

Converter Operating in

DCM for MVDC Grids

High-power dc–dc converter is the

essential component for connecting the

renewable energy sources to medium-

voltage dc (MVDC) grids. In this

paper, a novel zero voltage zero-current

switching converter with two full-

bridge cells sharing a bridge leg and

connecting the secondary windings of

two transformers in series is proposed

for MVDC applications. One big

feature of the proposed converter is that

the required inductance used for energy

transmission is reduced remarkably and

even can be embedded in the

transformer in some cases. Special but

simple control strategy adopted by the

converter makes it work in

discontinuous current mode, which can

realize zero-current switching for the

main switches and rectifier diodes in

the whole load range. Meanwhile, the

auxiliary switches with small current


rating can realize zero-voltage

switching naturally. Hence, the

switching loss is reduced, which is very

important for high-power applications.

The effects of the turns ratio of

auxiliary transformer on the total loss

and needed inductance are

comprehensively analyzed and proved.

With a detailed parameters design

procedure, a simulation model is

established in the software PLECS and

the operation principle of the converter

is verified. A 120 V–1200 V/1 kW

prototype was built to validate the

operation principle of the proposed

converter.

Soft Switching

Converter

A New ZVT Snubber

Cell for PWM-PFC

Boost Converter

In this paper, a new zero-voltage

transition (ZVT) snubber cell is

developed for pulse width modulated

(PWM) and power factor corrected

(PFC) boost converters operating in

continuous conduction mode. A new

family of PFC boost converter

implemented with this new ZVT

snubber cell is proposed. In this new

PFC boost converter, the main switch

is turned-on perfectly with ZVT and

turnedoff under zero-voltage switching

(ZVS). Besides, the auxiliary switch is

turned-on under zero current switching

and turned-off under ZVS. The main

and all auxiliary diodes are operating

under soft switching. During ZVT

operation, the switching energies on the

snubber inductance are transferred to

the output by a transformer, and so the

current stresses of the inductance and


the auxiliary switch are significantly

decreased. Also, this transformer

ensures the usage of sufficient

capacitors for ZVS turning off of the

main and auxiliary switches. The main

switch and main diode are not

subjected to any additional voltage and

current stresses. In this study, a detailed

steady-state analysis of the proposed

new ZVT-PWM-PFC boost converter

is presented and this theoretical

analysis is verified by a prototype with

100 kHz and 2 kW.

Soft Switching

Converter

High-Efficiency Soft-

Switching AC–DC

Converter With

Single-Power-

Conversion Method

This paper presents a high-efficiency

isolated ac–dc converter topology.

The proposed converter consists of a

full-bridge diode rectifier, an isolated

resonant dc–dc converter, and only

one controller. The proposed

converter provides the soft-switching

technique for all components

operating at high frequency,

allowing for an improvement in

power density without a cost of

power-conversion efficiency.

Furthermore, by using a novel

control algorithm that controls both

power factor and output power, the

converter performs ac–dc power

conversion in only a single-power

processing step. These characteristics

enable the proposed converter to

provide high efficiency, high power

density, and a high power factor. A

2-kW prototype was implemented,

and its performance and validity

were evaluated based on



Soft Switching

Converter

Soft-Switching Dual-

Fly back DC–DC

Converter With

Improved Efficiency

and Reduced Output

Ripple Current

This paper presents a soft-switching

dualflyback dc–dc converter with

improved efficiency and reduced

output ripple current. Zero-voltage-

switching (ZVS) technique and a dual-

flyback module for reducing the

number of snubber current paths are

adopted to improve efficiency. For the

ZVS technique, a self-driven

synchronous rectifier (SR) is used

instead of an output diode. By turning

the self-driven SR off after a short

delay, a main switch is turned on under

the ZVS condition. For reducing the

number of snubber current paths, a

dual-flyback module and a snubber

diode are used. When the main switch

is turned off, leakage inductance

energy is absorbed by a snubber diode

into an input source and a primary dc-

bus capacitor. Then, this energy is

reprocessed by the dual-flyback dc-dc

module to secondary side. Hence, there

is only one snubber current path. In

addition, the proposed converter

features a reduced output ripple current

because of the continuous current.

Consequently, the proposed converter

can achieve high efficiency and

reduced output ripple current. To verify

the performance of the proposed

converter, operating principles, steady-

state analyses, and experimental results

from a 340 to 24-V, 100-W prototype

are presented.

Resonant Converter Analysis and Design of This paper presents the analysis and


SQR-Based High-

Voltage LLC

Resonant DC–DC

Converter

design of an isolated high-voltage LLC

resonant dc–dc full-bridge converter

based on symmetrical quadrupler

rectifier (SQR). Unlike conventional

Cockcroft–Walton and full-bridge

diode rectifiers, the SQR circuit

provides significant improvement in

power density by reducing the

transformer turns-ratio without much

increase in the output impedance.

Moreover, the LLC converter can

provide additional voltage boost, if

operated, below the series resonant

frequency of the LLC tank. The

operating region of the converter is

chosen in such a way that the converter

always operates in ZVS for all line and

load conditions with additional voltage

boost. A new method based on basic

differential equation is proposed for the

accurate analysis and design of the

converter and subsequently, the key

results are compared with a first

harmonic approximation based analysis

method. A 120 V dc input, 2 kV

output, 200Wlaboratory

prototype has been designed, built, and

tested. Simulation and experimental

results shown in this paper demonstrate

the validity of

the analysis and design of the presented

converter

Resonant Converter

A New Dual-Bridge

Series Resonant DC-

DC Converter with

Dual-Tank

Compared to the dual active bridge

(DAB) converter, the dual-bridge series

resonant converter (DBSRC) can widen

soft-switching range. To further widen

the soft-switching range and improve


the circuit performance, a new dual-

bridge series resonant converter with

dual-tank based on DBSRC is proposed

in this paper. This new converter

features two resonant tanks and a

tapped-transformer, and it can perform

better than the DBSRC by optimized

tap-coefficient x of the tapped-

transformer. Its operation principle,

voltage gain, the soft-switching

characteristics and output power are

analyzed in detail, and compared with

the DBSRC. Results show that the

proposed dual-tank topology has

presented higher voltage gain, wider

soft-switching region, and larger output

power than the traditional DBSRC

when the tap-coefficient x is selected

reasonably. At last, a 1kW prototype is

built; experimental results verify the

feasibility and advantages of the

proposed dual-tank converter.

Resonant Converter

A Quasi-Resonant

Current-Fed Converter

With Minimum

Switching Losses

A quasi-resonant dc–dc converter with

high voltage

gain and low current stresses on

switches is proposed in this paper.

This converter preserved inherent

advantages of current-fed

structures, for instance, zero

magnetizing dc offset, low input ripple,

and low transformer turn ratio.

Moreover, by employing the

active-clamp circuit, the voltage spikes

across the main switch, due

to the existence of leakage inductance

of the isolating transformer,

is absorbed, and switches work in zero


voltage switching. Since

quasi-resonant switching strategy is

employed, turn-off current

(TOC) and losses of switches are

considerably reduced. Because of

zero current switching (ZCS), reverse

recovery problem of diodes

is alleviated. Experimental results on a

150-W prototype are provided

to validate the proposed concept.

Resonant Converter

Design and Steady-

State Analysis of

Parallel Resonant DC–

DC Converter for

High-Voltage Power

Generator

A novel voltage-doubling circuit with

parallelresonant

dc–dc converter is proposed. The

converter consists of

full-bridge inverter, resonant tank,

high-frequency high-voltage

transformer, and voltage-doubling

circuit. In the high-voltage

applications,

low-output voltage ripple has been

given much attention.

The output voltage step-up ratio is

increased by two parts.

One is a high-frequency high-voltage

transformer and the other is

a voltage-doubling circuit. The novel

voltage-doubling circuit can

not only reach a higher output voltage

but also reduce output ripple

to a lower level than the conventional

one. Therefore, while maintaining

the same output voltage, the

transformer’s turn ratio can

be reduced compared with the

conventional voltage-doubling circuit.

The output power can be adjusted by

the phase-shift control


technique. In addition, combining this

technique with the parallel

resonant tank can make all the switches

achieve zero voltage turn

on (ZVS). The operating principles,

steady-state analysis, and the

parameter designs are discussed in this

paper. Finally, a prototype

circuit with 400-V input voltage, 40-kV

output voltage, and

300-W output power is developed in

the laboratory to verify the

performance of the proposed converter

Resonant Converter

Dual-Bridge LLC

Resonant Converter

With Fixed-Frequency

PWM Control for Wide

Input Applications

This paper proposes a dual-bridge (DB)

LLC resonant

converter for wide input applications.

The topology is an integration

of a half-bridge (HB) LLC circuit and a

full-bridge (FB)

LLC circuit. The fixed-frequency

pulsewidth-modulated (PWM)

control is employed and a range of

twice the minimum input voltage

can be covered. Compared with the

traditional pulse frequency

modulation (PFM) controlled HB/FB

LLC resonant converter, the

voltage gain range is independent of

the quality factor, and the magnetizing

inductor has little influence on the

voltage gain, which can

simplify the parameter selection

process and benefit the design of

magnetic components as well. Over the

full load range, zero-voltage

switching (ZVS) and zero-current

switching (ZCS) can be achieved


for primary switches and secondary

rectifier diodes, respectively.

Detailed analysis on the modulation

schedule and operating principle

of the proposed converter is presented

along with the converter

performance. Finally, all theoretical

analysis and characteristics

are verified by experimental results

from a 120-V to 240-V input

24 V/20 A output converter prototype.

Z Source Converter

High-Performance

Quasi-Z-Source Series

Resonant DC–DC

Converter for

Photovoltaic Module-

Level Power

Electronics

Applications

This paper presents the high-

performance quasi-Zsource

series resonant dc–dc converter as a

candidate topology for

the photovoltaic module-level power

electronics applications. The

converter features a wide input voltage

and load regulation range

thanks to the multimode operation, i.e.,

when the shoot-through

pulse width modulation and phase-shift

modulation are combined

in a single switching stage to realize

the boost and buck operating

modes, respectively. Our experiments

confirmed that the proposed

converter is capable of ensuring ripple-

free 400 V output voltage

within the sixfold variation of the input

voltage (from 10 to

60 V). The converter prototype

assembled achieved a maximum

efficiency of 97.4%, which includes the

auxiliary power and

control system losses.

Z Source Converter Load and Source This paper proposes a battery simulator


Battery Simulator

Based on Z-Source

Rectifier

(BS) based

on a Z-source rectifier (ZSR), with the

intention of emulating the

discharge or charge characteristic of an

actual lithium-polymer

battery with high voltage and large

capacity. The proposed BS is

used for power testing for battery

applications. The battery model,

combinedwith a Shepherd model and

aTheveninmodel, is adopted

to freely change the properties and

specifications of the battery

and to replicate the dynamic behavior

of the battery, which is

discretized to utilize the digital

controller of the BS. The closedloop

voltage controller at the dc side of the

ZSR is designed to

emulate the rapid dynamic

characteristics of the battery based on

small-signal methods, considering the

influence of the components

of the impedance network. In this

paper, battery voltage control

algorithm (BVCA) is also utilized to

minimize the voltage stress

across switches while controlling two

dc-side voltages within a wide

range of output voltages. Simulation

and experimental results are

provided to verify the BS of the new

feature and the proposed

control method.

Z Source Converter

Wide Input-Voltage

Range Boost Three- To solve the problem of themismatched

voltage levels

between the dynamic lower voltage of


Level DC–DC

Converter With Quasi-

Z Source for Fuel Cell

Vehicles

the fuel cell stack and the

required constant higher voltage (400

V) of the dc-link bus of the

inverter for fuel cell vehicles, a boost

three-level dc–dc converter

with a diode rectification quasi-Z

source (BTL-DRqZ) is presented

in this paper, based on the conventional

flying-capacitor boost

three-level dc–dc converter.The

operating principle of a wide range

voltage-gain for this topology is

discussed according to the effective

switching states of the converter and

the multiloop energy communication

characteristic of the DRqZ source. The

relationship

between the quasi-Z source net

capacitor voltages, the modulation

index, and the output voltage is

deduced and then the static and

dynamic self-balance principle of the

flying-capacitor voltage

is presented. Furthermore, a boost

three-level dc–dc converter

with a synchronous rectification quasi-

Z source (BTL-SRqZ)

is additionally proposed to improve the

conversion efficiency.

Finally, a scale-down 1.2 kW BTL-

SRqZ prototype has been

created, and the maximum efficiency is

improved up to 95.66% by

using synchronous rectification. The

experimental results validate

the feasibility of the proposed topology

and the correctness of its


operating principles. It is suitable for

the fuel cell vehicles.

Z Source Converter

Quasi-Z-Source

Network-Based Hybrid

Power Supply

System for Aluminium

Electrolysis Industry

A hybrid power supply system (HPSS)

based

on the quasi-Z-source network is

proposed for aluminum

electrolysis, which can reduce energy

consuming and

carbon emission through the use of

renewable energy.

An ac–dc integrate controller is

designed in the HPSS

that contains a two-layer control. The

first layer control is

responsible for maintaining the dc bus

voltage and current,

which can mitigate negative effects

caused by anode effect

in aluminum electrolysis. The

independent maximum power

tracking for PV array and the dc-bus

voltage balance for

each quasi-Z-source dc–dc converter

can be achieved by

using the PV-voltage controller and dc-

bus voltage controller

for the PV System. To maintain the

voltage of dc bus

within the require voltage range of

aluminum electrolysis

production and ensure high input

power quality of ac

System, the quasi-Z-rectifier controller

is employed, which

can reduce the harmonic injection. The

power allocation is

addressed in the second control layer


and a power scheme

algorithm (PSA) is carried out to

maximize the system

efficiency and economic benefit. At

last, the simulation and

experimental results are provided to

verify the effectiveness

of the designed HPSS and the proposed

PSA.

Z Source Converter

Hybrid Z-Source Boost

DC–DC Converters

This paper presents a new family of

hybrid

Z-source boost dc–dc converters

intended for photovoltaic

applications, where the high step-up

dc–dc converters are

demanded to boost the low-source

voltages to a predefined

grid voltage. Because the boost

capabilities of the traditional

Z-source networks are limited, the

proposed converters

are composed of combine traditional Z-

source networks

in different ways to enhance the boost

abilities of the traditional

Z-source networks. The new version of

the proposed

Z-source converters is termed as hybrid

Z-source boost dc–

dc converters to satisfy the traditional

benefits of Z-source

networks with stronger voltage boost

abilities which can

also be applied to dc–ac, ac–ac, and

ac–dc power conversions.

The performances of the proposed

converters are


compared with other Z-source

networks behaviors. The simulation

and experimental results of the

proposed converters

are validated at different operating

conditions.

Interleaved Converter

Interleaved LLC

Resonant Converter

With Hybrid Rectifier

and Variable-

Frequency Plus Phase-

Shift control for Wide

Output Voltage Range

Applications

A family of two-phase interleaved LLC

(iLLC) resonant

converter with hybrid rectifier is

proposed for wide output

voltage range applications. The

primary sides of the two

LLC converters are in parallel, and the

connection of the secondary

windings in the two LLC converters

can be regulated by the hybrid

rectifier according to the output

voltage. Variable frequency

control is employed to regulate the

output voltage and the secondary

windings are in series when the output

voltage is high.

Fixed-frequency phase-shift control is

adopted to regulate the configuration

of the secondary windings as well as

the output voltage

when the output voltage is low. The

output voltage range is

extended by adaptively changing the

configuration of the hybrid

rectifier, which results in reduced

switching frequency range, circulating

current, and conduction losses of the

LLC resonant tank.

Zero voltage switching and zero

current switching are achieved for

all the active switches and diodes,


respectively, within the entire operation

range. The operation principles are

analyzed and a 3.5 kW

prototype with 400 V input voltage and

150–500 V output voltage is

built and tested to evaluate the

feasibility of the proposed method.


Zero-Voltage-

Transition Interleaved

Boost Converter With

an Auxiliary Coupled

Inductor

This paper proposes a soft-switched

interleaved

boost converter with minimal

conduction loss increment and

removed reverse-recovery problem.

The soft-switching operation

is enabled by a soft-switching cell

composed of passive components

in which an auxiliary coupled inductor

and a dc-link capacitor are

connected between the switch legs of

the interleaved boostmodules

and output stage. Every MOSFET

switch of the proposed boost

converter operates with zero-voltage

switching turn-on using the

coupled inductor current.

Consequently, the switching loss of

the proposed interleaved boost

converter is greatly reduced. In

addition, the reduced circulating

current in the auxiliary circuit

minimizes the increment of the

conduction loss. The proposed

soft-switched interleaved boost

converter operation is verified

with 500-W experimental results.


A Novel Interleaved

Non isolated Ultrahigh- This paper presents an interleaved

nonisolated

dc–dc converter with high-voltage gain


Step-Up DC–DC

Converter With ZVS

Performance

and

zero-voltage switching (ZVS)

performance. Both coupled

inductor and voltage multiplier cell

techniques are used

to increase the voltage gain. The ZVS

circuit is composed

of an active clamp which is in series

with the output

filter capacitors. This will give rise to

further extension of

the voltage gain. Applying the

interleaving technique at

the input of the converter, the ripple of

the input current

is reduced. Due to the leakage

inductances of coupled

inductors, the diodes are turned-off

under zero-current

switching condition. Hence, the reverse

current recovery

problem is alleviated. The steady-state

analysis of the

proposed converter is also presented.

Finally, a 900-V to

415-W laboratory prototype is

implemented to validate the

performance of the proposed converter


Discontinuous Current

Mode Operation of

Two-Phase

Interleaved Boost Dc-

dc Converter with

Coupled-inductor

A two-phase interleaved boost dc-dc

converter with

an inversely coupled inductor in a

discontinuous current mode

(DCM) is analyzed by the equivalent

inductance method.

Coupling effects on the circuit

statuses are described, and a

forced conduction of the power diode


or reverse-paralleled diode

of MOSFET is caused by coupling.

As a result, three major

circuit statuses are figured out

according to the physical

relationship between the input-

output voltage ratio and the

coupling-coefficient, and their

condition boundaries are used to

classify the DCM operation modes.

Then, considering the load

(duty cycle) variation, ten DCM

operation modes are

comprehensively analyzed. The

analysis can be used to make an

easy prediction of operation modes,

and extended to the analysis

of an interleaved buck converter or

buck/boost bidirectional

converter with a coupled-inductor in

DCM. At last, a 300 W

prototype is built and tested in the

lab to verify the analysis.


A Novel Soft-

Switching Interleaved

Coupled-Inductor

Boost

Converter with Only

Single Auxiliary

Circuit

A novel soft-switching interleaved

coupled- inductor boost converter is

proposed in this paper. Only a single

active soft-switching module is needed

to simultaneously achieve the soft-

switching property of the two switches

in the interleaved coupled- inductor

boost converter. The better efficiency is

achieved with the less components and

cost. The two main switches can

achieve the ZVT turn-on and smaller-

current turn-off simultaneously when

the single active soft-switching module

is active. Due to the coupling


characteristic of the inductors, the

voltages across the two inductors are

changed at the same time; therefore,

the equivalent circuit is equal to the

parasitic capacitors of the two main

switches in parallel to resonate with the

auxiliary inductor. By coupling two

input inductors, the volume and cost of

the circuit can be reduced. The

interleaved coupled-inductor topology

can also reduce the input and output

current ripples and share the input and

output currents. The operating modes,

analysis, and design of the proposed

circuit have been discussed in this

paper. Simulation and experiments are

finally conducted to verify the validity

of the proposed circuit.

Power Systems

Voltage Control with

PV Inverters in Low

Voltage Networks

In some rural and sub-urban areas, the

hosting capacity

(HC) of low voltage networks is

restricted by voltage limits.

With local voltage control,

photovoltaic generators can mitigate

the voltage rise partly and, therefore,

increase the HC. This paper

investigates the effectiveness and

general performance of different

reactive and active power control

concepts. It presents the findings

of an extensive simulation-based

investigation into the effectiveness

of voltage rise mitigation, additional

reactive power flows, network

losses, and power curtailment. The two

most common implementations

of reactive power control have a similar


effectiveness. The

voltage rise can be compensated for by

up to 25% and more than

60% for typical cable and overhead

(OH) feeders, respectively. By

additionally using active power

curtailment of up to 3% of the

annual yield, the HC can be increased

by about 50% and 90%

for the considered cable and OH

feeder, respectively (purely rural

feeders).

Power Systems

Unbalanced Control

Strategy for A

Thyristor-Controlled

LCCoupling

Hybrid Active Power

Filter in Three-Phase

Three-

Wire Systems

This paper proposes a control strategy

for a threephase

three-wire thyristor-controlled LC-

coupling hybrid active

power filter (TCLC-HAPF), which can

balance active power and

compensate reactive power and

harmonic currents under unbalanced

loading. Compared with TCLC-HAPF

with conventional

control strategy, active power filters

and hybrid active power filters

which either fail to perform satisfactory

compensation or require

high-rating active inverter part for

unbalanced compensation, a

control strategy was proposed for

TCLC-HAPF to operate with a

small rating active inverter part for a

variety of loads with satisfactory

performance. The control idea is to

provide different firing

angles for each phase of the thyristor-

controlled LC-coupling part

(TCLC) to balance active power and


compensate reactive power,

while the active inverter part aims to

compensate harmonic currents.

First, the required different TCLC

impedances are deduced.

Then, independent firing angles

referenced to the phase angle of

voltage across TCLC are calculated.

After angle transformations,

final firing angles referenced to phase

angle of load voltages are

obtained. In this paper, a novel

controller for TCLC-HAPF under

unbalanced loading is proposed.

Simulation and experimental

results are provided to verify the

effectiveness of the proposed controller

in comparison with a state-of-the-art

controller

Power Systems

Low-Capacitance

Cascaded H-Bridge

Multilevel STATCOM

This paper introduces a cascadedH-

bridge multilevel

converter (CHB-MC)-based StatCom

system that is able to operate

with extremely low dc capacitance

values. The theoretical limit is

calculated for the maximum capacitor

voltage ripple, and hence

minimum dc capacitance values that

can be used in the converter.

The proposed low-capacitance

StatCom (LC-StatCom) is able to

operate with large capacitor voltage

ripples, which are very close

to the calculated theoretical maximum

voltage ripple. The maximum

voltage stress on the semiconductors in

the LC-StatCom is


lower than in a conventional StatCom

system. The variable cluster

voltage magnitude in the LC-StatCom

system drops well below

the maximum grid voltage, which

allows a fixed maximum voltage

on the individual capacitors. It is

demonstrated that the proposed

LC-StatCom has an asymmetric V–I

characteristic, which is especially

suited for operation as a reactive power

source within the

capacitive region. A high-bandwidth

control system is designed for

the proposed StatCom to provide

control of the capacitor voltages

during highly dynamic transient events.

The proposedLC-StatCom

system is experimentally verified on a

low-voltage seven-

levelCHBMCprototype.

The experimental results show

successful operation

of the system with ripples as high as

90% of the nominal dc voltage.

The required energy storage for the

LC-StatCom system shows

significant reduction compared to a

conventional StatCom design]

Documents

IEEE BASEPAPER 2017 POWER ELECTRONICS