Final Year IEEE Project 2013-2014 - Power Electronics Project Title and Abstract

Elysium Technologies Private Limited Singapore | Madurai | Chennai | Trichy | Coimbatore | Cochin | Ramnad |

Pondicherry | Trivandrum | Salem | Erode | Tirunelveli

http://www.elysiumtechnologies.com, [email protected]

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Advanced Technologies & Tools

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all Languages

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Kerala & Karnataka.

Ticketing & Appointment Systems.

Individual Care for every Student.

Around 250 Developers & 20

Researchers




227-230 Church Road, Anna Nagar, Madurai – 625020.

0452-4390702, 4392702, + 91-9944793398.

[email protected], [email protected]

S.P.Towers, No.81 Valluvar Kottam High Road, Nungambakkam,

Chennai - 600034. 044-42072702, +91-9600354638,

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15, III Floor, SI Towers, Melapudur main Road, Trichy – 620001.

0431-4002234, + 91-9790464324.

[email protected]

577/4, DB Road, RS Puram, Opp to KFC, Coimbatore – 641002

0422- 4377758, +91-9677751577.

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mailto:[email protected]

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Plot No: 4, C Colony, P&T Extension, Perumal puram, Tirunelveli-

627007. 0462-2532104, +919677733255,

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1st Floor, A.R.IT Park, Rasi Color Scan Building, Ramanathapuram

- 623501. 04567-223225,

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Road, Opp. Bus stand, Erode-638 011. 0424-4030055, +91-

9677748477 [email protected]

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4200640 +91-9677704822

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TNHB A-Block, D.no.10, Opp: Hotel Ganesh Near Busstand. Salem

– 636007, 0427-4042220, +91-9894444716.

[email protected]




ETPL

PE-001

Review of the Impact of Vehicle-to-Grid Technologies on Distribution Systems and

Utility Interfaces

Abstract: Plug-in vehicles can behave either as loads or as a distributed energy and power resource in a

concept known as vehicle-to-grid (V2G) connection. This paper reviews the current status and

implementation impact of V2G/grid-to-vehicle (G2V) technologies on distributed systems, requirements,

benefits, challenges, and strategies for V2G interfaces of both individual vehicles and fleets. The V2G

concept can improve the performance of the electricity grid in areas such as efficiency, stability, and

reliability. A V2G-capable vehicle offers reactive power support, active power regulation, tracking of

variable renewable energy sources, load balancing, and current harmonic filtering. These technologies can

enable ancillary services, such as voltage and frequency control and spinning reserve. Costs of V2G

include battery degradation, the need for intensive communication between the vehicles and the grid,

effects on grid distribution equipment, infrastructure changes, and social, political, cultural, and technical

obstacles. Although V2G operation can reduce the lifetime of vehicle batteries, it is projected to become

economical for vehicle owners and grid operators. Components and unidirectional/bidirectional power

flow technologies of V2G systems, individual and aggregated structures, and charging/recharging

frequency and strategies (uncoordinated/coordinated smart) are addressed. Three elements are required

for successful V2G operation: power connection to the grid, control and communication between vehicles

and the grid operator, and on-board/off-board intelligent metering. Success of the V2G concept depends

on standardization of requirements and infrastructure decisions, battery technology, and efficient and

smart scheduling of limited fast-charge infrastructure. A charging/discharging infrastructure must be

deployed. Economic benefits of V2G technologies depend on vehicle aggregation and

charging/recharging frequency and strategies. The benefits will receive increased a- tention from grid

operators and vehicle owners in the future.

ETPL

PE-002

An LLC Resonant DC–DC Converter for Wide Output Voltage Range Battery

Charging Applications

Abstract: In this paper, resonant tank design procedure and practical design considerations are presented

for a high performance LLC multiresonant dc-dc converter in a two-stage smart battery charger for

neighborhood electric vehicle applications. The multiresonant converter has been analyzed and its

performance characteristics are presented. It eliminates both low- and high-frequency current ripple on

the battery, thus maximizing battery life without penalizing the volume of the charger. Simulation and

experimental results are presented for a prototype unit converting 390 V from the input dc link to an

output voltage range of 48-72 V dc at 650 W. The prototype achieves a peak efficiency of 96%.

ETPL

PE-003 An Advanced Power Electronics Interface for Electric Vehicles Applications

Abstract: Power electronics interfaces play increasingly important role in the future clean vehicle

technologies. This paper proposes a novel integrated power electronics interface (IPEI) for battery electric

vehicles (BEVs) in order to optimize the performance of the powertrain. The proposed IPEI is responsible



http://www.elysiumtechnologies.com, [email protected] for the power-flow management for each operating mode. In this paper, an IPEI is proposed and designed

to realize the integration of the dc/dc converter, on-board battery charger, and dc/ac inverter together in

the BEV powertrain with high performance. The proposed concept can improve the system efficiency and

reliability, can reduce the current and voltage ripples, and can reduce the size of the passive and active

components in the BEV drivetrains compared to other topologies. In addition, low electromagnetic

interference and low stress in the power switching devices are expected. The proposed topology and its

control strategy are designed and analyzed by using MATLAB/Simulink. The simulation results related to

this research are presented and discussed. Finally, the proposed topology is experimentally validated with

results obtained from the prototypes that have been built and integrated in our laboratory based on

TMS320F2808 DSP.

ETPL

PE-004 Auxiliary Switch Control of a Bidirectional Soft-Switching DC/DC Converter

Abstract: In this paper, the auxiliary switch control using a lookup table is proposed to enhance the

efficiency of the bidirectional dc/dc converter used in electric vehicle, which performs soft switching.

Continuous current data are difficult to obtain during a resonant operation due to the limit of DSP ADC

capacity. The proposed auxiliary switch control has a lookup table reference of the auxiliary switch turn-

on time. The control method properly controls the auxiliary switch turn-on time according to the required

load current; this auxiliary switch control brings the more efficient control in generative and regenerative

mode operation. The proposed approach has been validated by the results of experiments on a

bidirectional dc/dc converter, inverter, and interior permanent magnet synchronous motor.

ETPL

PE-005

A High Step-Up Three-Port DC–DC Converter for Stand-Alone PV/Battery Power

Systems

Abstract: A three-port dc-dc converter integrating photovoltaic (PV) and battery power for high step-up

applications is proposed in this paper. The topology includes five power switches, two coupled inductors,

and two active-clamp circuits. The coupled inductors are used to achieve high step-up voltage gain and to

reduce the voltage stress of input side switches. Two sets of active-clamp circuits are used to recycle the

energy stored in the leakage inductors and to improve the system efficiency. The operation mode does not

need to be changed when a transition between charging and discharging occurs. Moreover, tracking

maximum power point of the PV source and regulating the output voltage can be operated simultaneously

during charging/discharging transitions. As long as the sun irradiation level is not too low, the maximum

power point tracking (MPPT) algorithm will be disabled only when the battery charging voltage is too

high. Therefore, the control scheme of the proposed converter provides maximum utilization of PV power

most of the time. As a result, the proposed converter has merits of high boosting level, reduced number of

devices, and simple control strategy. Experimental results of a 200-W laboratory prototype are presented

to verify the performance of the proposed three-port converter.




ETPL

PE-006

A Nonlinear Controller Based on a Discrete Energy Function for an AC/DC Boost PFC

Converter

Abstract: AC/DC converter systems generally have two stages: an input power factor correction (PFC)

boost ac/dc stage that converts input ac voltage to an intermediate dc voltage while reducing the input

current harmonics injected to the grid, followed by a dc/dc converter that steps up or down the

intermediate dc-bus voltage as required by the output load and provides high-frequency galvanic

isolation. Since a low-frequency ripple (second harmonic of the input ac line frequency) exists in the

output voltage of the PFC ac/dc boost converter due to the power ripple, the voltage loop in the

conventional control system must have a very low bandwidth in order to avoid distortions in the input

current waveform. This results in the conventional PFC controller having a slow dynamic response

against load variations with adverse overshoots and undershoots. This paper presents a new control

approach that is based on a novel discrete energy function minimization control law that allows the front-

end ac/dc boost PFC converter to operate with faster dynamic response than the conventional controllers

and simultaneously maintain near unity input power factor. Experimental results from a 3-kW ac/dc

converter built for charging traction battery of a pure electric vehicle are presented in this paper to

validate the proposed control method and its superiority over conventional controllers.

ETPL

PE-007

Modular Multilevel Inverter with New Modulation Method and Its Application to

Photovoltaic Grid-Connected Generator

Abstract: This paper proposed an improved phase disposition pulse width modulation (PDPWM) for a

modular multilevel inverter which is used for Photovoltaic grid connection. This new modulation method

is based on selective virtual loop mapping, to achieve dynamic capacitor voltage balance without the help

of an extra compensation signal. The concept of virtual submodule (VSM) is first established, and by

changing the loop mapping relationships between the VSMs and the real submodules, the voltages of the

upper/lower arm's capacitors can be well balanced. This method does not requiring sorting voltages from

highest to lowest, and just identifies the MIN and MAX capacitor voltage's index which makes it suitable

for a modular multilevel converter with a large number of submodules in one arm. Compared to carrier

phase-shifted PWM (CPSPWM), this method is more easily to be realized in field-programmable gate

array and has much stronger dynamic regulation ability, and is conducive to the control of circulating

current. Its feasibility and validity have been verified by simulations and experiments.

ETPL

PE-008

Review of Battery Charger Topologies, Charging Power Levels, and Infrastructure for

Plug-In Electric and Hybrid Vehicles

Abstract: This paper reviews the current status and implementation of battery chargers, charging power

levels, and infrastructure for plug-in electric vehicles and hybrids. Charger systems are categorized into

off-board and on-board types with unidirectional or bidirectional power flow. Unidirectional charging

limits hardware requirements and simplifies interconnection issues. Bidirectional charging supports

battery energy injection back to the grid. Typical on-board chargers restrict power because of weight,

space, and cost constraints. They can be integrated with the electric drive to avoid these problems. The



http://www.elysiumtechnologies.com, [email protected] availability of charging infrastructure reduces on-board energy storage requirements and costs. On-board

charger systems can be conductive or inductive. An off-board charger can be designed for high charging

rates and is less constrained by size and weight. Level 1 (convenience), Level 2 (primary), and Level 3

(fast) power levels are discussed. Future aspects such as roadbed charging are presented. Various power

level chargers and infrastructure configurations are presented, compared, and evaluated based on amount

of power, charging time and location, cost, equipment, and other factors.

ETPL

PE-009

A Fully Directional Universal Power Electronic Interface for EV, HEV, and PHEV

Applications

Abstract: This study focuses on a universal power electronic interface that can be utilized in any type of

the electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs). Basically, the

proposed converter interfaces the energy storage device of the vehicle with the motor drive and the

external charger, in case of PHEVs. The proposed converter is capable of operating in all directions in

buck or boost modes with a noninverted output voltage (positive output voltage with respect to the input)

and bidirectional power flow.

ETPL

PE-010 Comprehensive Approach to Modeling and Simulation of Photovoltaic Arrays

Abstract: This paper proposes a method of modeling and simulation of photovoltaic arrays. The main

objective is to find the parameters of the nonlinear I-V equation by adjusting the curve at three points:

open circuit, maximum power, and short circuit. Given these three points, which are provided by all

commercial array data sheets, the method finds the best I-V equation for the single-diode photovoltaic

(PV) model including the effect of the series and parallel resistances, and warranties that the maximum

power of the model matches with the maximum power of the real array. With the parameters of the

adjusted I-V equation, one can build a PV circuit model with any circuit simulator by using basic math

blocks. The modeling method and the proposed circuit model are useful for power electronics designers

who need a simple, fast, accurate, and easy-to-use modeling method for using in simulations of PV

systems. In the first pages, the reader will find a tutorial on PV devices and will understand the

parameters that compose the single-diode PV model. The modeling method is then introduced and

presented in details. The model is validated with experimental data of commercial PV arrays.

ETPL

PE-011 VSC-Based HVDC Power Transmission Systems: An Overview

Abstract: The ever increasing progress of high-voltage high-power fully controlled semiconductor

technology continues to have a significant impact on the development of advanced power electronic

apparatus used to support optimized operations and efficient management of electrical grids, which, in

many cases, are fully or partially deregulated networks. Developments advance both the HVDC power

transmission and the flexible ac transmission system technologies. In this paper, an overview of the recent

advances in the area of voltage-source converter (VSC) HVdc technology is provided. Selected key



http://www.elysiumtechnologies.com, [email protected] multilevel converter topologies are presented. Control and modeling methods are discussed. A list of

VSC-based HVdc installations worldwide is included. It is confirmed that the continuous development of

power electronics presents cost-effective opportunities for the utilities to exploit, and HVdc remains a key

technology. In particular, VSC-HVdc can address not only conventional network issues such as bulk

power transmission, asynchronous network interconnections, back-to-back ac system linking, and

voltage/stability support to mention a few, but also niche markets such as the integration of large-scale

renewable energy sources with the grid and most recently large onshore/offshore wind farms.

ETPL

PE-012 Mitigation of Lower Order Harmonics in a Grid-Connected Single-Phase PV Inverter

Abstract: In this paper, a simple single-phase grid-connected photovoltaic (PV) inverter topology

consisting of a boost section, a low-voltage single-phase inverter with an inductive filter, and a step-up

transformer interfacing the grid is considered. Ideally, this topology will not inject any lower order

harmonics into the grid due to high-frequency pulse width modulation operation. However, the nonideal

factors in the system such as core saturation-induced distorted magnetizing current of the transformer and

the dead time of the inverter, etc., contribute to a significant amount of lower order harmonics in the grid

current. A novel design of inverter current control that mitigates lower order harmonics is presented in

this paper. An adaptive harmonic compensation technique and its design are proposed for the lower order

harmonic compensation. In addition, a proportional-resonant-integral (PRI) controller and its design are

also proposed. This controller eliminates the dc component in the control system, which introduces even

harmonics in the grid current in the topology considered. The dynamics of the system due to the

interaction between the PRI controller and the adaptive compensation scheme is also analyzed. The

complete design has been validated with experimental results and good agreement with theoretical

analysis of the overall system is observed.

ETPL

PE-013

Enhanced Modulation Strategy for a Three-Phase Dual Active Bridge—Boosting

Efficiency of an Electric Vehicle Converter

Abstract: Three-phase dual active bridge (3p-DAB) dc-to-dc converters are typically avoided in low-

power applications especially for wide voltage and power ranges. Even so, the 3p-DAB do offer a means

to reduce filter costs and volume. The aim of this study is to propose the triangular and trapezoidal

modulation for the 3p-DAB to address the problem of poor partial load efficiency. The proposed

modulation schemes were compared with two conventional DAB concepts. It was found that the

efficiency of the 3p-DAB increased substantially. Moreover, the 3p-DAB showed a considerably lower

filter volume than that of the single-phase dual active bridge converter (1p-DAB). In conclusion, a

modulation strategy combining the two proposed modulation schemes with the phase-shift modulation is

ideal, because they boost efficiency and take most benefit from the inherent low filter volume. Ultimately,

the three-phase dual active bridge may offer a promising solution to miniaturize galvanically isolated dc-

to-dc converters for electric vehicles.




ETPL

PE-014 Power Electronic Traction Transformer-Low Voltage Prototype

Abstract: Recently, a world's first ever power electronic traction transformer (PETT) for 15 kV, 16 2/3Hz

railway grid, has been newly developed, commissioned, and installed on the locomotive, where it is

presently in use. This marks an important milestone in the traction world. The design and development of

the PETT are described in this paper, where a low-voltage (LV) PETT prototype is presented. It has been

designed for the purposes of control hardware and software commissioning, thus serving a role of an

analogue simulator. In this paper, emphasis is placed on the overall system requirements, from where

control system has been developed, implemented, and successfully commissioned. The development of a

1.2MVA medium-voltage PETT prototype will be reported separately in accompanying paper.

ETPL

PE-015

DQ-Frame Modeling of an Active Power Filter Integrated With a Grid-Connected,

Multifunctional Electric Vehicle Charging Station,

Abstract: The paper first proves the existence of a nonlinear, feedback loop due to the effect of an active

power filter (APF) on the grid voltage for a multifunctional electric vehicle charging station. A linear,

open-loop model is derived based on direct quadrature (DQ)-theory in discrete time (DT). Based on this

model, a linear, closed-loop model is further developed with DQ-theory in DT. A triangle-hold equivalent

instead of a zero-order-hold equivalent is employed in the model for better representation. The developed

linear, closed-loop model is finally generalized to general power systems. Simulations are carried out to

verify the developed models under transient conditions. The short-time (1-2 ms), transient stability of the

grid with an APF is determined with the developed model. In contrast to existing stability analyses in the

phasor domain, using DQ-theory can linearize the loop and simplify the loop model in DT domain.

ETPL

PE-016

Development of an 85-kW Bidirectional Quasi-Z-Source Inverter With DC-Link Feed-

Forward Compensation for Electric Vehicle Applications

Abstract: This paper presents a detailed operation analysis, controller design, and realization of a high-

power, bidirectional quasi-Z-source inverter (BQ-ZSI) for electric vehicle applications. The circuit

analysis shows that with a bidirectional switch in the quasi-Z-source network, the performance of the

inverter under small inductance and low power factor can be improved. Based on the circuit analysis, a

small signal model of the BQ-ZSI is derived, which indicates that the circuit is prone to oscillate when

there is disturbance on the dc input voltage. Therefore, a dedicated voltage controller with feed-forward

compensation is designed to reject the disturbance and stabilize the dc-link voltage during a non-shoot-

through state. An 85-kW prototype has been built. Both simulation and experimental results are presented

to prove the functionality of the circuit and the effectiveness of the proposed control strategy.

ETPL

PE-017

Novel Interleaved Bidirectional Snubberless Soft-Switching Current-Fed Full-Bridge

Voltage Doubler for Fuel-Cell Vehicles

Abstract: This paper presents a novel interleaved soft-switching bidirectional snubberless current-fed full-

bridge voltage doubler (dc/dc converter) for an energy storage system in fuel cell electric vehicles. A



http://www.elysiumtechnologies.com, [email protected] novel secondary modulation technique is also proposed to clamp the voltage across the primary-side

switches naturally with zero-current commutation. It, therefore, eliminates the necessity for an external

active-clamped circuit or passive snubbers to absorb the switch turn-off voltage spike, a major challenge

in current-fed converters. Zero-current switching of primary-side devices and zero-voltage switching of

secondary-side devices are achieved, which significantly reduce switching losses. An interleaved design

is adopted over a single cell to increase the power handling capacity obtaining merits of lower input

current ripple, reduction of passive components' size, reduced device voltage and current ratings, reduced

conduction losses due to current sharing, and better thermal distribution. Primary device voltage is

clamped at rather low-reflected output voltage, which enables the use of low-voltage semiconductor

devices having low on-state resistance. Considering input current is shared between interleaved cells,

conduction loss of the primary side, a considerable part of total loss, is significantly reduced and higher

efficiency can be achieved to obtain a compact and higher power density system. Steady-state operation,

analysis, and design of the proposed topology have been presented. Simulation is conducted over software

package PSIM 9.0.4 to verify the accuracy of the proposed analysis and design. A 500-W prototype has

been built and tested in the laboratory to validate the converter performance.

ETPL

PE-018 An Improved Soft-Switching Buck Converter With Coupled Inductor

Abstract: This letter presents a novel topology for a buck dc-dc converter with soft-switching capability,

which operates under a zero-current-switching condition at turn on and a zero-voltage-switching

condition at turn off. In order to realize soft switching, based on a basic buck converter, the proposed

converter added a small inductor, a diode, and an inductor coupled with the main inductor. Because of

soft switching, the proposed converter can obtain a high efficiency under heavy load conditions.

Moreover, a high efficiency is also achieved under light load conditions, which is significantly different

from other soft-switching buck converters. The detailed theoretical analyses of steady-state operation

modes are presented, and the detailed design methods and some simulation results are also given. Finally,

a 600 W prototype is built to validate the theoretical principles. The switching waveforms and the

efficiencies are also measured to validate the proposed topology.

ETPL

PE-019

Photovoltaic Power-Increment-Aided Incremental-Conductance MPPT With Two-

Phased Tracking

Abstract: This paper presents a two-phased tracking that forms a photovoltaic (PV) power-increment-

aided incremental-conductance (PI-INC) maximum power point tracking (MPPT) to improve the tracking

behavior of the conventional INC MPPT. The PI-INC MPPT performs, using either variable-frequency

constant-duty control (VFCD) or constant-frequency variable-duty control (CFVD), with reference to a

collectively called threshold-tracking zone (TTZ), beyond which a power-increment (PI) tracking along

the Ppv -Vpv curve executes and within which an INC tracking along the Ipv-Vpv curve toward

maximum power point (MPP) does. Delay tracking due to ambiguous conductance-increment detection in

the flat portion of the left-hand side of the MPP along the Ipv -Vpv curve will not appear in the PI-INC

MPPT by using the PI tracking with clear and correct power-increment detection along the Ppv- Vpv

curve. In addition, the merit of INC MPPT to accurately track against the random solar insolation change



http://www.elysiumtechnologies.com, [email protected] still retains in the PI-INC MPPT that uses INC tracking toward MPP along the Ipv -Vpv curve when

tracking in the TTZ. Modeling and analysis of two typical PV power converters with VFCD and CFVD

controls are addressed for implementing the tracking of the PI-INC MPPT in design and experiment. The

tracking behavior of PI-INC MPPT and the conventional INC MPPT is assessed and compared through

elaborate experimental tests

ETPL

PE-020

A Zero-Voltage Switching Full-Bridge DC--DC Converter With Capacitive Output

Filter for Plug-In Hybrid Electric Vehicle Battery Charging

Abstract: In this paper, a novel zero-voltage switching full-bridge converter with trailing edge pulse width

modulation and capacitive output filter is presented. The target application for this study is the second

stage dc-dc converter in a two stage 1.65 kW on-board charger for a plug-in hybrid electric vehicle. For

this application the design objective is to achieve high efficiency and low cost in order to minimize the

charger size, charging time, and the amount and the cost of electricity drawn from the utility. A detailed

converter operation analysis is presented along with simulation and experimental results. In comparison to

a benchmark full-bridge with an LC output filter, the proposed converter reduces the reverse recovery

losses in the secondary rectifier diodes, therefore, enabling a converter switching frequency of 100 kHz.

Experimental results are presented for a prototype unit converting 400 V from the input dc link to an

output voltage range of 200-450 V dc at 1650 W. The prototype achieves a peak efficiency of 95.7%.

ETPL

PE-021 Current Minimizing Torque Control of the IPMSM Using Ferrari’s Method

Abstract: For the torque control of an interior permanent magnet synchronous motor (IPMSM), it is

necessary to determine a current command set that minimizes the magnitude of the current vector. This is

known as the maximum torque per ampere. In the field-weakening region, current minimizing solutions

are found at the intersection with the voltage limits. However, the optimal problem yields fourth-order

polynomials (quartic equations), and no attempt has been made to solve these quartic equations online for

torque control. Instead, premade lookup tables are widely used. These lookup tables tend to be huge

because it is necessary to create separate tables on the basis of the dc-link voltage and motor temperature.

In this study, we utilize Ferrari's method, which gives the solution to a quartic equation, for the torque

control. Further, a recursive method is also considered to incorporate the inductance change from the core

saturation. A simulation and some experiments were performed using an electric vehicle motor, which

demonstrated the validity of the proposed method.

ETPL

PE-022

A Novel Single-Reference Six-Pulse-Modulation (SRSPM) Technique-Based

Interleaved High-Frequency Three-Phase Inverter for Fuel Cell Vehicles

Abstract: This paper presents a hybrid modulation technique consisting of singe-reference six-pulse-

modulation (SRSPM) for front-end dc/dc converter and 33% modulation for three-phase inverter.

Employing proposed novel SRSPM to control front-end dc/dc converter, high frequency (HF) pulsating

dc voltage waveform is produced, which is equivalent to six-pulse output at 6× line frequency (rectified



http://www.elysiumtechnologies.com, [email protected] 6-pulse output of balanced three-phase ac waveforms) once averaged. It reduces the control complexity

owing to single-reference three-phase modulation as compared to conventional three-reference three-

phase SPWM. In addition, it relives the need of dc-link capacitor reducing the cost and volume.

Eliminating dc link capacitor helps in retaining the modulated information at the input of the three-phase

inverter. It needs only 33% (one third) modulation of the inverter devices to generate balanced three-

phase voltage waveforms resulting in significant saving in (at least 66%) switching losses of inverter

semiconductor devices. At any instant of line cycle, only two switches are required to switch at HF and

remaining switches retain their unique state of either ON or OFF. Besides, inverter devices are not

commutated when the current through them is at its peak value. Drop in switching loss accounts to be

around 86.6% in comparison with a standard voltage source inverter (VSI) employing standard three-

phase sine pulse width modulation. This paper explains operation and analysis of the HF two-stage

inverter modulated by the proposed novel modulation scheme. Analysis has been verified by simulation

results using PSIM9.0.4. Experimental results demonstrate effectiveness of the proposed modulation.

ETPL

PE-023 The Multilevel Modular DC Converter

Abstract: The modular multilevel converter (M2C) has become an increasingly important topology in

medium- and high-voltage applications. A limitation is that it relies on positive and negative half-cycles

of the ac output voltage waveform to achieve charge balance on the submodule capacitors. To overcome

this constraint a secondary power loop is introduced that exchanges power with the primary power loops

at the input and output. Power is exchanged between the primary and secondary loops by using the

principle of orthogonality of power flow at different frequencies. Two modular multilevel topologies are

proposed to step up or step down dc in medium- and high-voltage dc applications: the tuned filter

modular multilevel dc converter and the push–pull modular multilevel dc converter. An analytical

simulation of the latter converter is presented to explain the operation.

ETPL

PE-024 Dynamic Stability of a Microgrid With an Active Load

Abstract: Rectifiers and voltage regulators acting as constant power loads form an important part of a

microgrid's total load. In simplified form, they present a negative incremental resistance and beyond that,

they have control loop dynamics in a similar frequency range to the inverters that may supply a microgrid.

Either of these features may lead to a degradation of small-signal damping. It is known that droop control

constants need to be chosen with regard to damping, even with simple impedance loads. Actively

controlled rectifiers have been modeled in nonlinear state-space form, linearized around an operating

point, and joined to network and inverter models. Participation analysis of the eigenvalues of the

combined system identified that the low-frequency modes are associated with the voltage controller of the

active rectifier and the droop controllers of the inverters. The analysis also reveals that when the active

load dc voltage controller is designed with large gains, the voltage controller of the inverter becomes

unstable. This dependence has been verified by observing the response of an experimental microgrid to

step changes in power demand. Achieving a well-damped response with a conservative stability margin




does not compromise normal active rectifier design, but notice should be taken of the inverter-rectifier

interaction identified.

Education

Final Year IEEE Project 2013-2014 - Power Electronics Project Title and Abstract