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HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
Vi
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on
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S. No. IEEE TITLE ABSTRACT IEEE
YEAR
1.
A Boundary-Mode
Forward-Flyback
Converter With an
Efficient Active LC
Snubber Circuit
Abstract—This paper describes a boundary-mode
forwardflyback converter (BMFFC)with zero-voltage
switching that is able to process power efficiently. The
theoretical analysis and operating principle of the BMFFC
are presented in detail. A nondissipative LC snubber that
recycles energy to the input source is employed in order to
suppress the voltage spike caused by the leakage
inductance of the transformer. The relatively large
snubber capacitor also significantly reduces turn-off loss.
Following a detailed design procedure, a 200 W prototype
with a 25—50 V dc input and 230 V dc output was
constructed and tested in order to evaluate the
performance of the BMFFC.
2014
2.
A Cascaded Multilevel
Inverter Based on
Switched-Capacitor for
High-Frequency AC
Power Distribution
System
Abstract—The increase of transmission frequency reveals
more merits than low- or medium-frequency distribution
among different kinds of power applications. High-
frequency inverter serves as source side in high-frequency
ac (HFAC) power distribution system (PDS). However, it
is complicated to obtain a high-frequency inverter with
both simple circuit topology and straightforward
modulation strategy. A novel switched-capacitor-based
cascaded multilevel inverter is proposed in this paper,
which is constructed by a switched-capacitor frontend and
H-Bridge backend. Through the conversion of series and
parallel connections, the switchedcapacitor frontend
increases the number of voltage levels. The output
harmonics and the component counter can be significantly
reduced by the increasing number of voltage levels. A
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
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symmetrical triangular waveform modulation is proposed
with a simple analog implementation and low modulation
frequency comparing with traditional multicarrier
modulation. The circuit topology, symmetrical
modulation, operation cycles, Fourier analysis,
parameterdetermination, and topology enhancement are
examined. An experimental prototype with a rated output
frequency of 25 kHz is implemented to compare with
simulation results. The experimental results agreed very
well with the simulation that confirms the feasibility of
proposed multilevel inverter.
3.
A Center Point
Iteration MPPT
Method With
Application on the
Frequency Modulated
LLC Microinverter
Abstract—Maximum power point tracking (MPPT) is an
essential technique to harvest PV power under varying
environments. Perturb and observe (P&O) algorithms are
the most broadly used MPPT due to their effectiveness
and simplicity. However, it is difficult to balance the
tracking speed and oscillation requirements in the
conventional P&O with fixed perturb. Adaptive P&O
techniques have been proposed as a solution to these
problems. However, they are based on duty cycle
modulation for conventional pulse width modulation
converters. None of them deal with the variable
frequencymodulation for resonant converters. In this
paper, a center point iteration MPPT is proposed, with its
variable perturb in frequency. The proposed scheme
overcomes the drawbacks of conventional P&O with a
simple calculation. Moreover, it is suitable for various
power curves, especially the LLC microinverter power
curves, which may confuse conventional MPPT
algorithms. The effectiveness of the proposed MPPT
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
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method was verified in theory. A 300 W prototype was
constructed, and the experimental results verified the
effectiveness of the proposed center point iteration MPPT.
An advanced version was also introduced in order to
accelerate the tracking speed.
4.
A Critical Review of
Recent Progress in Mid
RangeWireless Power
Transfer
Abstract—Starting from Tesla’s principles of wireless
power transfer a century ago, this critical review outlines
recent magneto inductive research activities on wireless
power transfer with the transmission distance greater than
the transmitter coil dimension. It summarizes the
operating principles of a range of wireless power research
into 1) the maximum power transfer and 2) the maximum
energy efficiency principles. The differences and the
implications of these two approaches are explained in
terms of their energy efficiency and transmission distance
capabilities. The differences between the system energy
efficiency and the transmission efficiency are also
highlighted. The review covers the two-coil systems, the
four-coil systems, the systems with relay resonators and
the wireless domino-resonator systems. Related issues
including human exposure issues and reduction of
winding resistance are also addressed. The review
suggests that the use of the maximum energy efficiency
principle in the two-coil systems is suitable for short-
range rather than mid-range applications, the use of the
maximum power transfer principle in the four-coil
systems is good for maximizing the transmission distance,
but is under a restricted system energy efficiency (<50%);
the use of the maximum energy efficiency principle in
relay or domino systems may offer a good compromise
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
Vi
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for good system energy efficiency and transmission
distance on the condition that relay.
5.
A Current Balancing
Scheme With High
Luminous Efficacy for
High-Power LED
Lighting
Abstract—The imbalance in the currents of strings of
LEDs will cause fast degradation or even failure in some
LEDs. Such current imbalance should be avoided. To
balance the common average current, a small duty cycle
may necessitate a large LED turn-on current amplitude,
which may cause temporal overheat and low luminous
efficacy of the LEDs. This paper presents a current
balancing method based on pulse-width modulation of a
common bus voltage to each LED string to achieve the
intended average current. An optimal feedback control
scheme is proposed to maximize the duty cycles and
minimize the bus voltage. As a result, at least one of the
LED strings is operating at unity duty cycle. The analysis,
implementation, and verification are detailed in this paper.
2014
6.
A Four-level Hybrid-
Clamped Converter
With Natural Capacitor
Voltage Balancing
Ability
Abstract—This paper presents a novel four-level hybrid-
clamped converter topology which is composed of eight
switches and one flying capacitor per phase. The
operating principle is introduced and phase-shifted pulse
width modulation is used to control this converter.
Adetailed analysis of the average currents through the
flying capacitor and neutral points of the dc-link is
presented. Based on the analysis, it can be concluded that
the voltages across the flying capacitor and dc-link
capacitors can be naturally balanced under ideal and
steady-state condition. A low-power three-phase
prototype is built up and experimental results are
presented to validate the proposed topology and
modulation method.
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
Vi
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7.
A High Voltage Gain
DC–DC Converter
Integrating Coupled-
Inductor and Diode–
Capacitor Techniques
Abstract—The high-voltage gain converter is widely
employed in many industry applications, such as
photovoltaic systems, fuel cell systems, electric vehicles,
and high-intensity discharge lamps. This paper presents a
novel single-switch high step-up non isolated dc–dc
converter integrating coupled inductor with extended
voltage doubler cell and diode–capacitor techniques. The
proposed converter achieves extremely large voltage
conversion ratio with appropriate duty cycle and reduction
of voltage stress on the power devices. Moreover, the
energy stored in leakage inductance of coupled inductor is
efficiently recycled to the output, and the voltage doubler
cell also operates as a regenerative clamping circuit,
alleviating the problem of potential resonance between the
leakage inductance and the junction capacitor of output
diode. These characteristics make it possible to design a
compact circuit with high static gain and high efficiency
for industry applications. In addition, the unexpected
high-pulsed input current in the converter with coupled
inductor is decreased. The operating principles and the
steady state analyses of the proposed converter are
discussed in detail. Finally, a prototype circuit is
implemented in the laboratory to verify the performance
of the proposed converter.
2014
8. A Hybrid Symmetrical
Voltage Multiplier
Abstract—Voltage multiplier circuits are widely used in
many high-voltage/low-current applications. A
conventional symmetrical voltage multiplier (SVM) has
much better performance, when compared with its half-
wave counterpart. However, it requires a high-voltage
transformer (HVT) with center-tapped secondary to
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
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perform its push–pull kind of operation. The design of an
HVT with center-tapped secondary is relatively complex.
This paper proposes a hybrid SVM (HSVM) for dc high-
voltage applications. The multiplier is formed by
cascading a diode-bridge rectifier and an SVM with
diode-bridge rectifier as the first stage of multiplier. The
proposed topology saves two high-voltage capacitors and
requires only one secondary winding of HVT. Besides, it
has lesser voltage drop and faster transient response at
start-up, when compared with conventional SVM. The
feasibility of the proposed HSVM is validated both by
simulation and experimental results of a laboratory
scaled-down prototype.
9.
A Low Complexity
Control System for a
Hybrid DC Power
Source Based on
Ultracapacitor Lead–
Acid Battery
Configuration
Abstract—A dc hybrid power source based on the
combination of ultra capacitor and lead–acid battery is
considered in this paper. The various control systems for
such hybrid power source reported in the technical
literature thus far are rather complex. A low complexity
control system for such hybrid power source is proposed
in this paper. The key feature of the proposed control
system is its capability to maintain operation of the hybrid
power source within all important operational limits. The
proposed control system allows one to allocate the high-
frequency current demands to the ultra capacitor and
specify the current limits for both the battery and the ultra
capacitor. It also maintains operation of the battery within
its state of charge limits and the ultra capacitor voltage at
a predefined value while charging the ultra capacitor from
the battery rather than from the common dc bus. Presented
experimental results verify the satisfactory operation of
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
Vi
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the power source utilizing the proposed control system.
10.
A Novel Transformer-
less Adaptable Voltage
Quadrupler DC
Converter with Low
Switch Voltage Stress
Abstract—In this paper, a novel transformer-less
adjustable voltage quadrupler dc–dc converter with high-
voltage transfer gain and reduced semiconductor voltage
stress is proposed. The proposed topology utilizes input-
parallel output-series configuration for providing a much
higher voltage gain without adopting an extreme large
duty cycle. The proposed converter cannot only achieve
high step-up voltage gain with reduced component count
but also reduce the voltage stress of both active switches
and diodes. This will allow one to choose lower voltage
rating MOSFETs and diodes to reduce both switching and
conduction losses. In addition, due to the charge balance
of the blocking capacitor, the converter features automatic
uniform current sharing characteristic of the two
interleaved phases for voltage boosting mode without
adding extra circuitry or complex control methods. The
operation principle and steady analysis as well as a
comparison with other recent existing high step-up
topologies are presented. Finally, some simulation and
experimental results are also presented to demonstrate the
effectiveness of the proposed converter.
2014
11. A Novel ZVT-ZCT-
PWM Boost Converter
Abstract—In this study, a new boost converter with an
active snubber cell is proposed. The active snubber cell
provides main switch to turn ON with zero-voltage
transition (ZVT) and to turn OFF with zero-current
transition (ZCT). The proposed converter incorporating
this snubber cell can operate with soft switching at high
frequencies. Also, in this converter all semiconductor
devices operate with soft switching. There is no additional
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
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voltage stress across the main and auxiliary components.
The converter has a simple structure, minimum number of
components, and ease of control as well. The operation
principle and detailed steady-state analysis of the novel
ZVT-ZCT-PWM boost converter are given. The presented
theoretical analysis is verified exactly by a prototype of
100 kHz and 1 kW converter. Also, the overall efficiency
of the new converter has reached a value of 97.8% at
nominal output power.
12.
A Pulse Igniting Circuit
for Electronic Ballast
With the ZVS-QSW
Converter
Abstract—In the paper, a novel pulse ignition circuit is
proposed for electronic ballast with the zero-voltage-
switching quasi-square wave (ZVS-QSW) converter; the
voltage pulse of the proposed igniting circuit contains
both a high frequency part and a low frequency part; the
high frequency part made it easy to exit the gas in the
ionization conduction state in the high-intensity discharge
lamp, and the low frequency part makes it easy to lower
the igniting potential and provides the continuous pulse
energy. The circuit is with few components, low costs,
high reliability, and easy to control. The circuit model is
analyzed in detail and the influence of the circuit
parameters on the pulse amplitude and width is given in
this paper. The peak current is limited and the amplitude
variation caused by the deviation of the parasitic capacitor
for the transformer is restricted by the auxiliary inductor.
The auxiliary inductor and the transformer parasitic
capacitor form another resonant circuit. As a result, an
igniting pulse sequence with two different frequencies is
applied to the lamp and both pulse amplitude and width
are guaranteed. In the laboratory, the circuit is used in a
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
Vi
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70-W metal halide lamp electronic ballast with the ZVS-
QSW converter, and the lamp can be ignited reliably.
13.
A Solar Power
Generation System
With a Seven-Level
Inverter
Abstract—This paper proposes a new solar power
generation system, which is composed of a dc/dc power
converter and a new seven-level inverter. The dc/dc
power converter integrates a dc–dc boost converter and a
transformer to convert the output voltage of the solar cell
array into two independent voltage sources with multiple
relationships. This new seven-level inverter is configured
using a capacitor selection circuit and a full-bridge power
converter, connected in cascade. The capacitor selection
circuit converts the two output voltage sources of dc–dc
power converter into a three-level dc voltage, and the full-
bridge power converter further converts this three-level dc
voltage into a seven-level ac voltage. In this way, the
proposed solar power generation system generates a
sinusoidal output current that is in phase with the utility
voltage and is fed into the utility. The salient features of
the proposed seven-level inverter are that only six power
electronic switches are used, and only one power
electronic switch is switched at high frequency at any
time. A prototype is developed and tested to verify the
performance of this proposed solar power generation
system.
2014
14.
A Space-Vector
Modulation Method for
Common-Mode
Voltage Reduction in
Current-Source
Converters
Abstract—The common-mode voltage (CMV) produced
from a converter system is a source of many problems,
e.g., in the motor drive system, CMV might appear at the
neutral point of the motor stator windings with respect to
the ground and induce destructive bearing current.
Reduced CMV space-vector modulation (RCMV SVM)
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
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methods have been proposed in both voltage-source
converter (VSC) and current-source converter (CSC)
systems. The available RCMV SVMs reduce the CMV by
avoiding using zero state vectors. However, this will lead
to some negative effects, such as shrink of modulation
index range, increase of switching frequencies, bipolar
line-to-line voltage pulse patterns in VSCs, and power
quality performance deterioration. In this paper, a RCMV
SVM method for CSCs is proposed. By allowing the use
of zero state vectors, the proposed RCMV SVM still
produces much lower CMV. However, its other
performance indices, such as switching frequency and
harmonic performance, are unaffected and comparable to
the conventional SVMs. The effectiveness of the
proposed RCMV SVM for CSCs is verified in the
simulations and experiments.
15.
A Switched Capacitor-
Based Active-Network
Converter With High
Voltage Gain
Abstract—The voltage gain of traditional boost converter
is limited due to the high current ripple, high voltage
stress across active switch and diode, and low efficiency
associated with large duty ratio operation. High voltage
gain is required in applications, such as the renewable
energy power systems with low input voltage. A high
step-up voltage gain active-network converter with
switched capacitor technique is proposed in this paper.
The proposed converter can achieve high voltage gain
without extremely high duty ratio. In addition, the voltage
stress of the active switches and output diodes is low.
Therefore, low voltage components can be adopted to
reduce the conduction loss and cost. The operating
principle and steady-state analysis are discussed in detail.
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
Vi
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on
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s
A prototype with 20–40-V input voltage, 200-V output
voltage, and 200-W output power has been established in
the laboratory. Experimental results are given to verify the
analysis and advantages of the proposed converter.
16.
A Three-Level
Integrated AC–DC
Converter
Abstract—In this paper, a new integrated three-level ac–
dc converter is presented. The proposed converter
integrates the operation of the boost power factor
correction and the three-level dc–dc converter. The
converter is made to operate with two independent
controllers—an input controller that performs power
factor correction and regulates the dc bus and an output
controller that regulates the output voltage. The input
controller prevents the dc-bus voltage from becoming
excessive while still allowing a single-stage converter
topology to be used. The paper explains the operation of
the new converter in detail and discusses its features and a
procedure for its proper design. Experimental results
obtained from a prototype are presented to confirm the
feasibility of the new converter.
2014
17.
A Transformerless
Grid-Connected
Photovoltaic System
Based on the Coupled
Inductor Single-Stage
Boost Three-Phase
Inverter
Abstract—This letter presents a modulation technique for
the modified coupled-inductor single-stage boost inverter
(CL-SSBI)-based grid-connected photovoltaic (PV)
system. This technique can reduce the system leakage
current in a great deal and can meet the VDE0126-1-1
standard. To maintain the advantages of the impedance
network, only a diode is added in the front of the original
topology, to block the leakage current loop during the
active vectors and open-zero vectors. On the other hand,
the near state pulse width modulation (NSPWM)
technique is applied with one-leg shoot-through zero
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
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vectors in order to reduce the leakage current through the
conduction path in the duration of changing from and to
open-zero vectors. Simultaneously, the leakage current
caused by other transitions can also be reduced due to the
fact that the magnitude of common-mode voltages is
reduced. Simulation results of the transformer less PV
system are presented in two cases: modified CL-SSBI
modulated by maximum constant boost (MCB) control
method and NSPWM. Experimental results for both
CLSSBI topology modulated by the MCB control method
and modified CL-SSBI topology modulated by NSPWM
are also obtained to verify the accurateness of theoretical
and simulation models.
18.
A Two-Mode Control
Scheme With Input
Voltage Feed-Forward
for the Two-Switch
Buck-Boost DC–DC
Converter
Abstract—The two-switch buck-boost (TSBB) converter
is suitable for wide input voltage applications. In order to
achieve high efficiency over the entire input voltage
range, the TSBB converter is operated in buck mode at
high input voltage and boost mode at low input voltage.
Such operation is called the two-mode control scheme.
The objective of this paper is to propose an input voltage
feed-forward (IVFF) method to reduce the influence of
the input voltage disturbance on the output voltage. The
small-signal models of the TSBB converter are built, and
based on which, the IVFF functions under different
operating modes of the TSBB converter are derived. The
IVFF function in boost mode is simplified for easy
implementation. The two-mode control scheme with IVFF
compensation is then proposed for the TSBB converter,
which realizes automatic selections of operating modes
and the corresponding IVFF functions. Besides, nearly
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
Web site: www.visiongroups.org
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smooth switching between buck and boost modes is also
guaranteed. For exhibiting the advantages of the proposed
control scheme clearly, comparisons between the two-
mode control with and without IVFF compensation have
been presented in this paper, including the output signal
of the voltage regulator and input-to-output voltage
transfer function. Finally, a 250−500-V input, 360-V
output, and 6-kW-rated power prototype is fabricated to
validate the effectiveness of the proposed control scheme
in the laboratory, and the experimental results show that
the TSBB converter has an improved input transient
response and high efficiency over the entire input voltage
range with this proposed control scheme.
19.
A Two-Phase
Interleaved Power
Factor Correction
Boost Converter With a
Variation-Tolerant
Phase Shifting
Technique
Abstract—This paper presents a two-phase interleaved
critical conduction mode (CRM) power factor correction
boost converter with a variation-tolerant phase shifter
(VTPS), which ensures accurate 180◦ phase shift between
the two interleaved converters. A feedback loop similar to
a phase-locked loop controls the amount of the phase
shifting of the VTPS. The proposed VTPS has better
immunity of process, supply, and temperature variations
than the conventional phase shifter. A 320-W two-phase
interleaved CRM boost converter prototype has been
implemented, while the proposed VTPS and conventional
interleaving phase shifter can be selectively applied to
compare the performance of the proposed technique with
the conventional one. Experimental results show that the
two-phase interleaved CRM boost converter has better
performance with the proposed VTPS. The proposed
VTPS circuit can be applied to any type of interleaved
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
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switching power converter.
20.
A Unified Control
Strategy for Three-
Phase Inverter in
Distributed Generation
Abstract—This paper presents a unified control strategy
that enables both islanded and grid-tied operations of
three-phase inverter in distributed generation, with no
need for switching between two corresponding controllers
or critical islanding detection. The proposed control
strategy composes of an inner inductor current loop, and a
novel voltage loop in the synchronous reference frame.
The inverter is regulated as a current source just by the
inner inductor current loop in grid-tied operation, and the
voltage controller is automatically activated to regulate
the load voltage upon the occurrence of islanding.
Furthermore, the waveforms of the grid current in the
grid-tied mode and the load voltage in the islanding mode
are distorted under nonlinear local load with the
conventional strategy. And this issue is addressed by
proposing a unified load current feed forward in this
paper. Additionally, this paper presents the detailed
analysis and the parameter design of the control strategy.
Finally, the effectiveness of the proposed control strategy
is validated by the simulation and experimental results.
2014
21.
A Zero-Voltage
Switching Three-Phase
Inverter
Abstract—A new modulation scheme for the active
clamping zero-voltage switching (ZVS) inverter is
proposed. With the proposed modulation scheme, the
inverter can realize ZVS operation in all switching
devices and can remarkably suppress the reverse recovery
current in insulated-gate bipolar transistor’s anti parallel
diodes as well. All the switches can operate at a fixed
frequency in the new modulation scheme. Also, with the
new modulation scheme, the ZVS inverter has some
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
E-Mail:visionsolutions.9@gmail.com, call-9603150547
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voltage boost capability, which is suitable for renewable
energy generation. The inverter can achieve ZVS in all the
switches under the grid current power factor angle from
zero to ±π/6. The soft-switching condition of this inverter
is analyzed. The operation principal and design guideline
are described in detail. The previous theory is verified in a
30-kW inverter prototype.
22.
Active Islanding
Detection for Multiple
Parallel-Connected
Inverter-Based
Distributed Generators
Using High-Frequency
Signal Injection
Abstract—This paper proposes a method for islanding
detection in micro grids with multiple parallel-connected
inverters using high-frequency signal injection. In the
proposed method, a master inverter injects the high-
frequency signal which is used by the rest of inverters for
islanding detection, with two distinguishing features: 1)
The slave inverters work in a high-frequency current
cancellation mode, what prevents interference and 2) in
case of master failure or significant changes in the grid,
the remaining inverters will dynamically reassign roles,
the new master inverter being self-selected, based on a
deterministic performance criteria and without the need of
communications.
2014
23.
An FPGA-Based Gain-
Scheduled Controller
for Resonant
Converters Applied to
Induction Cooktops
Abstract—Domestic induction heating appliances have
become popular due to their advantages such as
efficiency, fast heating, cleanliness, and safety. In order to
achieve high efficiency, induction cook tops usually
features resonant converters in which the inductor-vessel
system is a part of the resonant tank. Thus, the inductor-
vessel system impedance sets the point of operation of the
power converter. Due to the variability of the load with
multiple parameters such as temperature, geometry, and
material, the resonant converter has to work with highly
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varying operating conditions. When designing a classical
controller, the controller gain is selected to assure the
system stability in the whole range of operation and for a
large amount of vessels. This study proposes an FPGA-
based gain scheduled controller which makes use of the
information of the modulation parameters and an online
impedance identification system. As a result, the proposed
controller significantly improves the converter dynamic
response, improving the performance and safety operation
of the power converter. The proposed control algorithm
has been experimentally verified using a domestic
induction heating prototype, proving the feasibility of this
proposal.
24.
An Improved Droop
Control Method for DC
Microgrids Based on
Low Bandwidth
Communication With
DC Bus Voltage
Restoration and
Enhanced Current
Sharing Accuracy
Abstract—Droop control is the basic control method for
load current sharing in dc microgrid applications. The
conventional dc droop control method is realized by
linearly reducing the dc output voltage as the output
current increases. This method has two limitations. First,
with the consideration of line resistance in a droop
controlled dc microgrid, since the output voltage of each
converter cannot be exactly the same, the output current
sharing accuracy is degraded. Second, the dc-bus voltage
deviation increases with the load due to the droop action.
In this paper, in order to improve the performance of the
dc microgrid operation, a low-bandwidth communication
(LBC)-based improved droop control method is proposed.
In contrast with the conventional approach, the control
system does not require a centralized secondary
controller. Instead, it uses local controllers and the LBC
network to exchange information between converter units.
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The droop controller is employed to achieve independent
operation, and the average voltage and current controllers
are used in each converter to simultaneously enhance the
current sharing accuracy and restore the dc bus voltage.
All of the controllers are realized locally, and the LBC
system is only used for changing the values of the dc
voltage and current. Hence, a decentralized control
scheme is accomplished. The simulation test based on
MATLAB/Simulink and the experimental validation
based on a 2 × 2.2 kW prototype were implemented to
demonstrate the proposed approach.
25.
An Improved ZVT–
ZCT PWM DC–DC
Boost Converter With
Increased Efficiency
Abstract—A new active snubber cell is proposed for a dc–
dc boost converter. Zero voltage transition (ZVT) turn on
and zero current transition (ZCT) turn off are provided by
this active snubber cell. There is no extra current or
voltage stresses on the main switch. Also, zero current
switching (ZCS) turn on and ZCT turn off are provided
for the auxiliary switch. Although there is no extra
voltage stress on the auxiliary switch, a current stress is
present. However, auxiliary switch current stress is
decreased by coupling inductance. The coupling
inductance transfers the part of the current stress to the
output load according to the transform ratio. In this paper,
the ZVT–ZCT PWM dc–dc boost converter’s steadystate
analysis is proposed for one switching cycle.
Experimental application and theoretical analysis are
proved by 300 W prototype with 100 kHz switching
frequency. As a result, an improved ZVT–ZCT
PWMboost converter reaches 98.7% total efficiency at
full load with lowered current stress.
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26.
Analysis and
Implementation of an
Improved Flyback
Inverter for
Photovoltaic AC
Module Applications
Abstract—Flyback inverter has the advantages such as
compact conformation, simple control loop, electric
isolation, high step-up ratio, high efficiency, etc.,
therefore is an attractive solution for photovoltaic ac
module applications. In this topology, BCM is more
preferred compared to DCM and CCM, because of its
higher power level, higher efficiency and wider switching
frequency bandwidth. However, the control of BCM is
more complicated due to its variable switching frequency.
This also leads to the difficulty to get the accurate
mathematical model between the output current iout and
the reference current iref , which has a great influence on
the THD of iout . This paper analyzes and proposes a
mathematical model between iout and iref in BCM
through theoretical derivation, and proposes a novel
control strategy to generate the reference current that can
decrease THD of output current. Meanwhile the
realization of MPPT based on the mathematical model is
also investigated. Finally, simulation and experiment
results based on an improved fly back-inverter prototype
are presented, which validates the proposed mathematical
model and the control strategy.
2014
27.
Analysis of Unified
Output MPPT Control
in Subpanel PV
Converter System
Abstract—Photovoltaic (PV) systems frequently suffer
disproportionate impacts on energy production due to
mismatch cases. To remedy this, academia proposed a
distributed max power point tracking (MPPT) solution
and has been implemented commercially. Taking the
trend of the “distributed MPPT” concept a step further,
this paper discusses and analyzes an MPPT converter that
connects to each PV cell string, called a subpanel MPPT
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converter (SPMC), to better address the real-world
mismatch issues. The SPMC system with a unified output
MPPT control structure is also proposed in order to
reduce the cost and simplify the distributed MPPT system.
The proposal saves A/D units, current sensors, and MPPT
controllers on the premise of guaranteeing that the SPMC
is working on its optimal maximum power point
regardless of th mismatch case. This is favorable for the
further integration and makes the whole SPMC system
less expensive and easier to realize. Finally, the
effectiveness of the proposal is confirmed experimentally.
28.
Asymmetrical Grid
Fault Ride-Through
Strategy of Three-
Phase Grid-Connected
Inverter Considering
Network
ImpedanceImpact in
Low-Voltage Grid
Abstract—This letter presents a new control strategy of
three phase grid-connected inverter for the positive
sequence voltage recovery and negative sequence voltage
reduction under asymmetrical grid faults. Unlike the
conventional control strategy based on an assumption that
the network impedance is mainly inductive, the proposed
control strategy is more flexible and effective by
considering the network impedance impact, which is of
great importance for the high penetration of grid-
connected renewable energy systems into low-voltage
grids. The experimental tests are carried out to validate
the effectiveness of the proposed solution for the flexible
voltage support in a low-voltage grid, where the network
impedance is mainly resistive.
2014
29.
Class-D Zero-Current-
Switching Rectifier as
Power-Factor Corrector
for Lighting
Applications
Abstract—An analysis and design of a zero-current-
switching (ZCS) Class-D current-source driven rectifier
for the lighting applications is presented, which is one of
the resonant rectifiers as a power-factor corrector to
improve a poor power-factor and high line current
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harmonic of a single-stage converter. A high power factor
is achieved by the utilization of output characteristics of a
Class-D ZCS rectifier, which is inserted between the
front-end bridge rectifier and the bulk-filter capacitor. The
conduction angle of the bridge rectifier diode current was
increased and a low-line current harmonic and a power-
factor near unity can be obtained. The design procedure is
based on the principle of the Class-D ZCS rectifier, which
also ensures more accurate results and the proposed
scheme provides a high efficiency and amore systematic
and feasible analysis methodology. The active switches
can be operated under the soft-switching condition. The
validity of this approach was confirmed by simulation and
experimental results.
30.
Classification and
Comparative
Evaluation of PV
Panel-Integrated DC–
DC Converter
Concepts
Abstract—The strings of photovoltaic panels have a
significantly reduced power output when mismatch
between the panels occurs, as, e.g., caused by partial
shading. With mismatch, either the panel integrated
diodes are bypassing the shaded panels if the string is
operated at the current level of the un shaded panels, or
some power of the un shaded panels is lost if the string
current is reduced to the level of the shaded panels. With
the implementation of dc–dc converters on panel level,
the maximum available power can be extracted from each
panel regardless of any mismatch. In this paper, different
concepts of PV panel-integrated dc–dc converters are
presented and their suitability for panel integration is
evaluated. The buck–boost converter is identified as the
most promising concept and an efficiency/power density
(η-ρ) Pareto optimization of this topology is shown. Based
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on the optimization results, two 275W converter
prototypes with either Silicon MOSFETs with a switching
frequency of 100 kHz or gallium nitride FETs with a
switching frequency of 400 kHz are designed for an input
voltage range of 15 to 45 V and an output voltage range of
10 to 100 V. The theoretical considerations are verified by
efficiency measurements which are compared to the
characteristics of a commercial panel-integrated
converter.
31.
Common-Mode and
Differential-Mode
Active Damping for
PWM Rectifiers
Abstract—Modern pulse-width-modulated (PWM)
rectifiers use LCL filters that can be applied in both the
common mode and differential mode to obtain high-
performance filtering. Interaction between the passive L
and C components in the filter leads to resonance
oscillations. These oscillations need to be damped either
by the passive damping or active damping. The passive
damping increases power loss and can reduce the
effectiveness of the filter. Methods of active damping,
using control strategy, are lossless while maintaining the
effectiveness of the filters. In this paper, an active
damping strategy is proposed to damp the oscillations in
both line-to-line and line-to-ground. An approach based
on pole placement by the state feedback is used to actively
damp both the differential- and common-mode filter
oscillations. Analytical expressions for the state-feedback
controller gains are derived for both continuous and
discrete-time model of the filter. Tradeoff in selection of
the active damping gain on the lower order power
converter harmonics is analyzed using a weighted
admittance function. Experimental results on a 10-
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kVAlaboratory prototype PWM rectifier are presented.
The results validate the effectiveness of the active
damping method, and the tradeoff in the settings of the
damping gain.
32.
Comparative
Performance Analysis
of High Density and
Efficiency PFC
Topologies
Abstract—In this paper, the efficiency and power factor
performance of improved power factor correction (PFC)
topologies suitable for a high density and efficient design
are compared. Several topologies, including a
conventional average current mode control boost PFC, an
interleaved boost PFC, a back-to-back bridgeless boost
PFC, and a semi-bridgeless boost PFC, are assessed
through loss analysis and simulation using whole height 1
U and 2 kW class prototypes. Based on this, an optimal
topology is selected for which an additional comparative
analysis involving input line measure improvement
control is conducted. The results of these experiments can
be adapted for use in the circuit selection of high
performance converters with power factor improvement
circuits.
2014
33.
Control Strategy of
Three-Phase Battery
Energy Storage
Systems for Frequency
Support in Microgrids
and with Uninterrupted
Supply of Local Loads
Abstract—Frequency control in autonomous micro grids
(MG) with high penetration of renewable energy sources
represents a great concern to ensure the system stability.
In this regard, this paper presents an enhanced control
method for battery energy storage systems (BESS) to
support the frequency of MG and with the ability of
disconnecting from the MG to supplying in the island
mode a local consumer. A frequency controller,
combining a conventional droop control with an inertia
emulation function, governs the BESS active power
transfer during the primary frequency control level. The
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BESS may also provide voltage support in the point of
common coupling with the MG. Moreover, the proposed
BESS may compensate, partially or totally, the power
absorbed by the local loads in order to improve the MG
frequency response. When the MG power quality worsens
below a certain level, in terms of voltage and frequency,
the BESS detaches from the MG and continues to operate
islanded. The reconnection is accomplished following a
smoothly resynchronization of the local voltage with the
MG, without disturbing the local loads supply.
Additionally, this paper also discusses about the aspects
related to the BESS management and its integration
within the proposed system. The simulation and
experimental results assess the feasibility of the proposed
control solutions.
34.
Design and
Implementation of a
High-Efficiency
Multiple-Output
Resonant Converter for
Induction Heating
Applications Featuring
Wide Bandgap Devices
Abstract—Efficiency is a key design parameter when
designing the power converters for domestic induction
heating applications, since it determines not only the
environmental impact of the power converter but also its
final performance and reliability. In this paper, he design
of high-efficiency converters for induction heating
applications is discussed, focusing on the advantages of
using wide band gap devices. As a conclusion, a multiple-
output boost resonant ac–ac converter is proposed,
significantly improving current state of- the-art efficiency
and achieving a reduced component-count solution for
multiple-load systems. The proposed converter has been
tested through a dual-output boost resonant inverter for
domestic induction heating applications. The design
procedure is detailed, including the design of an
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optimized gate drive circuit for this application.
Experimental results show significant improvements in
efficiency in the whole operating range, and an accurate
output power control, proving the benefits and feasibility
of the proposed SiC-based converter.
35.
Design and
Implementation of a
High-Power-Factor
LED Driver With Zero-
Voltage Switching-On
Characteristics
Abstract—This paper proposes a novel light-emitting
diode (LED) driver consisting of a buck-boost converter
and a buck converter. Each converter adopts a power
MOSFET as the active switch. With no need to use any
auxiliary switches or snubber circuits, both active
switches can operate at zero-voltage switching on (ZVS)
by freewheeling the inductor current of the converters to
flow through the intrinsic diodes of the MOSFETS. The
buck-boost converter is operated at discontinuous-
conduction mode (DCM) to perform the function of
power-factor correction to ensure almost unity power
factor at the input line. The buck converter steps down the
output voltage of the buck-boost converter to drive LEDs.
It could be designed to operate at either DCM or
continuous conduction mode. The detailed circuit
operations and analysis are provided. A prototype 60-W
LED driver was built and tested. Experimental results
show that the switching losses can be effectively reduced
by operating the active switches at ZVS. The measured
power factor and circuit efficiency are as high as 0.99%
and 93%, respectively.
2014
36.
Design and
Implementation of
Energy Management
System With Fuzzy
Abstract—This paper presents the design and
implementation of an energy management system (EMS)
with fuzzy control for adc microgrid system. Modeling,
analysis, and control of distributed power sources and
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Control for DC
Microgrid Systems
energy storage devices with MATLAB/Simulink are
proposed, and the integrated monitoring EMS is
implemented with Lab VIEW. To improve the life cycle
of the battery, fuzzy control manages the desired state of
charge. The RS-485/ZigBee network has been designed to
control the operating mode and to monitor the values of
all subsystems in the dc microgrid system.
37.
Determining the Value
of DC-Link
Capacitance to Ensure
Stable Operation of a
Three-Phase
Photovoltaic Inverter
Abstract—Grid interfacing of photovoltaic generators
using three-phase inverters offers the advantage of
constant power flow allowing smaller capacitance values
to be used in the dc-link compared to single-phase
inverters. Electrolytic capacitors, used in the dc-link, are
often considered to decrease reliability. Reliability could
be improved by using film capacitors, but their usage is
limited by high cost and low capacitance. Much research
has been done to minimize the dc-link capacitance value,
particularly, in the field of drives and wind turbines. It has
been shown that motor drive in regenerative mode
contains a right-half-plane (RHP) pole in its control
dynamics having a significant effect on the required dc-
link capacitance. The RHP pole can cause instability as
has been observed in wind turbine applications.
Photovoltaic inverters have been reported to suffer from
instability of the dc-link-voltage control, but the origin of
the observed problems is poorly understood. This paper
shows explicitly that an RHP pole is present in the control
dynamics also in photovoltaic inverters affecting the
minimum required dc-link capacitance. The paper
proposes a minimum value for the dc-link capacitance that
is required for stable operation. Design rules are given for
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single- and two-stage inverters. Moreover, it is shown that
a source having constant power output effectively
removes the RHP pole from the dc-link-voltage control
dynamics.
38.
Development of an
FPGA-Based SPWM
Generator for High
Switching Frequency
DC/AC Inverters
Abstract—The digital implementations of Sinusoidal
Pulse Width Modulation (SPWM) generators have
dominated over their counterparts based on analog
circuits. In this paper, an FPGA based SPWM generator is
presented, which is capable to operate at switching
frequencies up to 1 MHz (requiring FPGA operation at
100–160 MHz), thus it is capable to support the high
switching frequency requirements of modern single-phase
dc/ac power converters. The proposed design occupies a
small fraction of a medium-sized FPGA and, thus, can be
incorporated in larger designs. Additionally, it has a
flexible architecture that can be tuned to a variety of
single-phase dc/ac inverter applications. The post layout
simulation and experimental results confirm that
compared to the past-proposed SPWM generation
designs, the SPWM generator presented in this paper
exhibits much faster switching frequency, lower power
consumption, and higher accuracy of generating the
desired SPWM waveform.
2014
39.
Digital DCM Detection
and Mixed Conduction
Mode Control for
Boost PFC Converters
Abstract—This paper presents a novel mixed conduction
mode (MCM) digital controller with a digital signal
processor (DSP)- based discontinuous conduction mode
(DCM) detection technique to realize total harmonic
distortion (THD) and power factor improvements in boost
power factor correction (PFC) converters operating in
both continuous conduction mode (CCM) and DCM
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during a single ac line half-cycle. By using the integrated
comparators found on many DSPs, simplification and
cost-reductions over existing DCM and zero-current
detection methods are made possible. Additionally,
performance improvements over a conventional CCM
digital control technique are possible with simple software
modification, and can be extended to existing boost PFC
converter designs provided a compatible DSP is present.
At an output power of 98 W, an experimental 650 W
boost PFC converter operating in the MCM controlled by
a TMS320F28035 provides a THD reduction of 40.2%
and power factor improvement of 1.5% over a
conventional digital controller.
40.
Direct AC–AC
Resonant Boost
Converter for Efficient
Domestic Induction
Heating Applications
Abstract—Domestic induction heating (IH) is currently
the technology of choice in modern domestic applications
due to its advantages regarding fast heating time,
efficiency, and improved control. New design trends
pursue the implementation of new cost-effective
topologies with higher efficiency levels. In order to
achieve this aim, a direct ac–ac boost resonant converter
is proposed in this paper. The main features of this
proposal are the improved efficiency, reduced component
count, and proper output power control. A detailed
analytical model leading to closed-form expressions of the
main magnitudes is presented, and a converter design
procedure is proposed. In addition, an experimental
prototype has been designed and built to prove the
expected converter performance and the accurateness of
the analytical model. The experimental results are in good
agreement with the analytical ones and prove the
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feasibility of the proposed converter for the IH
application.
41.
Direct Grid Current
Control of LCL-
Filtered Grid-
Connected Inverter
Mitigating Grid
Voltage Disturbance
Abstract—A direct grid current control strategy for LCL-
filtered grid-connected inverters is proposed in this paper.
The conventional current control strategies are analyzed
and compared, and then the necessity of direct grid
current control is presented to mitigate the grid voltage
disturbance. In the proposed control strategy, the virtual
resistance based on the capacitance current is used to
realize active damping, zero compensation is brought in to
enhance the stability, and the proportional resonant (PR)
controller under two-phase static coordinate is designed to
track the ac reference current as well as to avoid the
strong coupling brought by the coordinate transformation.
Under the distortion grid voltage, the PR plus harmonic
compensator (PR+HC) structure is adopted to restrain the
distortion of the grid current. Finally, the proposed control
strategy is verified by the experimental results.
2014
42.
Direct Voltage Control
of DC–DC Boost
Converters Using
Enumeration-Based
Model Predictive
Control
Abstract—This paper presents a model predictive control
(MPC) approach for dc–dc boost converters. A discrete-
time switched nonlinear (hybrid) model of the converter is
derived, which captures both the continuous and the
discontinuous conduction mode. The controller synthesis
is achieved by formulating an objective function that is to
be minimized subject to the model dynamics. The
proposed MPC strategy, utilized as a voltage-mode
controller, achieves regulation of the output voltage to its
reference, without requiring a subsequent current control
loop. Furthermore, a state estimation scheme is
implemented that addresses load uncertainties and model
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mismatches. Simulation and experimental results are
provided to demonstrate the merits of the proposed
control methodology, which include a fast transient
response and a high degree of robustness.
43.
DTC of B4-Inverter-
Fed BLDC Motor
Drives With Reduced
Torque Ripple During
Sector-to-Sector
Commutations
Abstract—The paper deals with the direct torque control
(DTC) of brushless DC (BLDC) motor drives fed by four-
switch inverters (also known as B4-inverters) rather than
six-switch inverters (also known as B6-inverters) in
conventional drives. The B4-inverter could be regarded as
a reconfigured topology of the B6-inverter in case of a
switch/leg failure which represents a crucial reliability
benefit for many applications especially in electric and
hybrid propulsion systems. The principle of operation of
the BLDC motor is firstly recalled considering both cases
of B6- and B4-inverters in the armature, with emphasis on
the two- and three-phase conduction modes. Then, the
DTC of B4-inverter-fed BLDC motor drives is treated
considering three strategies, such as: 1) DTC-1: a strategy
inspired from the one intended to B6-inverter-fed BLDC
motor drives; 2) DTC-2: a strategy that considers a
dedicated vector selection sub table in order to
independently control the torques developed by the phases
connected to the B4-inverter legs during their
simultaneous conduction; and 3) DTC-3: a proposed
strategy that eliminates the torque dips penalizing DTC-2
during sector-to sector commutations. Following the
design of the corresponding vector selection tables and
sub tables (if any), an experimentally based comparative
study of the three DTC strategies is carried out
considering, in the first step, the BLDC motor steady-state
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operation under DTC-1 and DTC-3. Then, the comparison
is extended to the BLDC motor features during sector-to-
sector commutations, underDTC-2 andDTC-3. The
experimental results clearly validate the predicted
performance of the proposed DTC strategy.
44.
Dual Angle Control for
Line-Frequency-
Switched Static
Synchronous
Compensators Under
System Faults
Abstract—Voltage-sourced converter (VSC)-based static
synchronous compensators (STATCOMs) are used for
voltage regulation in transmission and distribution
systems. Unlike PWM controlled STATCOMs, angle-
controlled STATCOMs are switched at line frequency to
limit the system losses. In recent years, angle controlled
STATCOMs have been deployed by utilities for the
purpose of transmission system voltage regulation,
voltage stability improvement, and increasing operational
functionality. Despite the superior feature on voltage
waveform quality and efficiency, the practical angle-
controlled STATCOMs suffer from the over current (and
trips) and possible saturation of the interfacing
transformers caused by negative sequence current during
unbalanced conditions and faults in the utility. This paper
specifically proposes a control structure to improve the
angle-controlled STATCOMs performance under
unbalanced conditions and faults. The main improvement
is a substantial decrease in the negative sequence current
and dc-link voltage oscillations under power system faults
by the proposed control. This eliminates the need to
redesign the STACOM power components to operate
under fault current and dc link voltage oscillations. The
proposed control structure is designed based on adding
appropriate oscillations to the conventional angle
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controller output that is the control angle by which the
VSC voltage vector leads/lags the line voltage vector.
Since this control structure uses two angles for controlling
the VSC output voltage, it is called dual angle control
(DAC). PSCAD/EMTDC and experimental results verify
the validity of the proposed control structure under
unbalanced system conditions and faults. The experiments
were conducted on a transient network analyzer, a unique
hardware-based flexible ac transmission system simulator
which was designed to study system faults and transients
for a 2 × 100 MVA STATCOM field installation.
45.
Ga-Optimized
Parameters of Sliding-
Mode Controller Based
on Both Output voltage
and Input Current With
an Application in the
PFC of AC/DC
Converters
Abstract—In this work, analysis and optimization of
sliding mode controller parameters are treated, in order to
govern a static power converter. In this case, an ac–dc
boost power factor corrector is used; generally, these
kinds of converters are applied to obtain a power factor
near to unity. Advantage that the designed controller can
give is the improvement of dynamic and static
performances in cases of large disturbances. Simple
sliding surface contains, in most cases, only one variable;
in this study, analyzed surface includes two variables,
which are continuous output voltage and rectified
sinusoidal input current; the benefit of this surface is
getting react against various disturbances, as be at the
input power parameters, or the value of the load. The
whole controller and converter is tested by simulation and
experimentally for steady-state and transient responses.
2014
46.
H6 Transformerless
Full-Bridge PV Grid-
Tied Inverters
Abstract—Transformer less inverters are widely used in
grid-tied photovoltaic (PV) generation systems, due to the
benefits of achieving high efficiency and low cost.
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Various transformer less inverter topologies have been
proposed to meet the safety requirement of leakage
currents, such as specified in the VDE-4105 standard. In
this paper, a family of H6 transformer less inverter
topologies with low leakage currents is proposed, and the
intrinsic relationship between H5 topology, highly
efficient and reliable inverter concept (HERIC) topology,
and the proposed H6 topology has been discussed as well.
One of the proposed H6 inverter topologies is taken as an
example for detail analysis with operation modes and
modulation strategy. The power losses and power device
costs are compared among the H5, th HERIC, and the
proposed H6 topologies. A universal prototype is built for
these three topologies mentioned for evaluating their
performances in terms of power efficiency and leakage
currents characteristics. Experimental results show that
the proposed H6 topology and the HERIC achieve similar
performance in leakage currents, which is slightly worse
than that of the H5 topology, but it features higher
efficiency than that of H5 topology.
47.
High Efficiency Dual-
Mode Current
Modulation Method for
Low-Power DC/AC
Inverters
Abstract—Boundary conduction mode (BCM) zero
voltage switching (ZVS) current control is a promising
soft switching method for micro inverter applications. In
this letter, different BCM ZVS current control modulation
schemes are compared based on power losses breakdown,
switching frequency range, and current quality. Compared
to continuous conduction mode current control, BCM
ZVS control decreases MOSFET switching losses and
filter inductor conduction losses but increases MOSFET
conduction losses and inductor core losses. Based on the
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loss analysis, a dual-mode current modulation method
combining ZVS and zero current switching schemes is
proposed to improve the efficiency of the micro inverter.
The experimental results show that by using this proposed
current modulation scheme, higher efficiency of 0.5% can
be achieved with no additional cost for a 400-W three-
phase micro inverter.
48.
High Gain Soft-
Switching Bidirectional
DC–DC Converter for
Eco-Friendly Vehicles
Abstract—This paper proposes a non isolated soft-
switching bidirectional dc–dc converter suitable for high
step-up and step-down applications. The proposed
converter can achieve zero voltage switching turn on of
all switches and zero-current-switching turn off of some
switches in continuous conduction mode in both forward
and reverse modes. An optimized switching strategy is
presented to minimize switch current rating and achieve
soft switching in wider range. An intermediate switching
pattern is introduced to carry out seamless mode change.
Experimental results from a 5-kW prototype are provided
to validate the proposed concept.
2014
49.
High Power Density
Series Resonant
Inverter Using an
Auxiliary Switched
Capacitor Cell for
Induction Heating
Applications
Abstract—This paper proposes a unique topology of
voltage-fed high-frequency series load resonant inverter
with a lossless snubber capacitor and an auxiliary
switched cell for induction heating appliances. The main
objective of this paper is to demonstrate how high power
density can be achieved by including a switched capacitor
cell with the capacitor-clamped half-bridge zero voltage
switching high-frequency inverter circuit using the PWM
control scheme. The operation principle of the proposed
inverter circuit is based upon an asymmetrical duty cycle
pulse width modulated (PWM) control scheme. The
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operating performances of high-frequency ac regulation
and power conversion efficiency characteristics are shown
through experiments with their soft-switching operating
ranges.
50.
High Step-Up
Interleaved Converter
With Built-In
Transformer Voltage
Multiplier Cells for
Sustainable Energy
Applications
Abstract—In this paper, the built-in transformer voltage
multiplier cell is inserted into each phase of the
conventional interleaved boost converter to provide
additional control freedom for the voltage gain extension
without extreme duty cycle. The voltage multiplier cell is
only composed of the built-in transformer windings,
diodes and small capacitors. And additional active
switches are not required to simplify the circuit
configuration. Furthermore, the switch voltage stress and
the diode peak current are also minimized due to the built-
in transformer voltage multiplier cells to improve the
conversion efficiency. Moreover, there is no reverse-
recovery problem for the clamp diodes and the reverse
recovery current for the regenerative and output diodes
are controlled by the leakage inductance of the built-in
transformer to reduce the relative losses. In addition, the
switch turn-off voltage spikes are suppressed effectively
by the ingenious and inherent passive clamp scheme and
zero current switch (ZCS) turn-on is realized for the
switches, which can enhance the power device reliability.
Finally, a 40 V-input 380 V-output 1 kW prototype is
built to demonstrate the clear advantages of the proposed
converter.
2014
51.
High-Voltage Gain
Boost Converter Based
on Three-State
Abstract—This paper presents a novel high-voltage gain
boost converter topology based on the three-state
commutation cell for battery charging using PV panels
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Commutation Cell for
Battery Charging Using
PV Panels in a Single
Conversion Stage
and a reduced number of conversion stages. The presented
converter operates in zero-voltage switching (ZVS) mode
for all switches. By using the new concept of single-stage
approaches, the converter can generate a dc bus with a
battery bank or a photovoltaic panel array, allowing the
simultaneous charge of the batteries according to the
radiation level. The operation principle, design
specifications, and experimental results from a 500-W
prototype are presented in order to validate the proposed
structure.
52.
I2 Average Current
Mode Control for
Switching Converters
Abstract—Constant frequency average current mode
(ACM) control is a widely used control scheme for
converters requiring precise current control. However, its
transient response is relatively slow, while the switching
loss and driving loss significantly diminish the light load
efficiency. To solve these issues, the I2 control ACM is
proposed. By combining the fast direct current feedback
and integral feedback, the I2 control achieves both wide
bandwidth and accurate current control. As a particular
embodiment of this concept, by adopting constant on-time
modulation, constant on-time I2 control needs no artificial
ramp, and has a fast dynamic response. Moreover, due to
the decrease of the switching frequency, constant on-time
I2 control improves the efficiency in discontinuous
conduction mode. The concept of I2 control can be
extended to other modulations. A small-signal model
using the describing function- based equivalent circuit
model is proposed. The model is accurate up to 1/2
switching frequency. Based on the model, the design
guidelines are discussed. The proposed control is verified
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with simulation and hardware measurement results.
53.
Integrated
Inverter/Converter
Circuit and Control
Technique of Motor
Drives With Dual-
Mode Control for
EV/HEV Applications
Abstract—A new integrated circuit for motor drives with
dual mode control for EV/HEV applications is proposed.
The proposed integrated circuit allows the permanent
magnet synchronous motor to operate in motor mode or
acts as boost inductors of the boost converter, and thereby
boosting the output torque coupled to the same
transmission system or dc-link voltage of the inverter
connected to the output of the integrated circuit. In motor
mode, the proposed integrated circuit acts as an inverter
and it becomes a boost-type boost converter, while using
the motor windings as the boost inductors to boost the
converter output voltage. Moreover, a new control
technique for the proposed integrated circuit under boost
converter mode is proposed to increase the efficiency. The
proposed control technique is to use interleaved control to
significantly reduce the current ripple and thereby
reducing the losses and thermal stress under heavy-load
condition. In contrast, single phase control is used for not
invoking additional switching and conduction losses
under light-load condition. Experimental results derived
from digital-controlled 3-kW inverter/converter using
digital signal processing show the voltage boost ratio can
go up to 600Wto 3 kW. And the efficiency is 93.83%
under full-load condition while keeping the motor
temperature at the atmosphere level. These results fully
confirm the claimed merits for the proposed integrated
circuit.
2014
54. Isolated High Step-Up
DC–DC Converter
Abstract—Fuel cell stacks and photovoltaic panels
generate rather low dc voltages and these voltages need to
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With Low Voltage
Stress
be boosted before converted to ac voltage. Therefore, high
step-up ratio dc– dc converters are preferred in renewable
energy systems. A new Z-source-based topology that can
boost the input voltage to desired levels with low duty
ratios is proposed in this paper. The topology utilizes
coupled inductor. The leakage inductance energy can
efficiently be discharged. Since the device stresses are
low in this topology, low-voltage MOSFETs with small
RDS (on) values can be selected to reduce the conduction
loss. These features improve the converter efficiency.
Also, the converter has a galvanic steady-state analysis of
continuous and discontinuous conduction modes are
discussed in detail. Finally, experimental results are given
for a prototype converter that converts 25 V dc to 400 V
dc at various power levels with over 90% efficiency to
verify the effectiveness of the theoretical analysis.
55.
Magnetic Integration of
the LCL Filter in Grid-
Connected Inverters
Abstract—This letter investigates the magnetic integration
of the LCL filter in grid-connected inverters. By sharing
an ungapped core and arranging the windings properly,
the fundamental fluxes generated by the two inductors of
an LCL filter cancel out mostly in the common core.
Thus, the common core with low flux level can be
dramatically reduced. Although the reluctance of the
common core can hardly be zero, which implies an
inevitable coupling between the integrated inductors, the
proposed magnetic integration scheme is still attractive if
the cross-section area and magnetic material of the
common core are made reasonable. Experimental results
from both single-phase and three-phase grid-connected
inverters verify the effectiveness of the proposed method.
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56.
Maximum Power Point
Tracking Using Model
Reference Adaptive
Control
Abstract—This paper proposes an adaptive control
architecture for maximum power point tracking (MPPT)
in photovoltaic systems. MPPT technologies have been
used in photovoltaic systems to deliver the maximum
available power to the load under changes of the solar
insolation and ambient temperature. To improve the
performance of MPPT, this paper develops a two-level
adaptive control architecture that can reduce complexity
in system control and effectively handle the uncertainties
and perturbations in the photovoltaic systems and the
environment. The first level of control is ripple correlation
control (RCC), and the second level is model reference
adaptive control (MRAC). By decoupling these two
control algorithms, the system achieves MPPT with
overall system stability. This paper focuses mostly on the
design of the MRAC algorithm, which compensates the
under damped characteristics of the power conversion
system. The original transfer function of the power
conversion system has time-varying parameters, and its
step response contains oscillatory transients that vanish
slowly. Using the Lyapunov approach, an adaption law of
the controller is derived for the MRAC system to
eliminate the under damped modes in power conversion.
It is shown that the proposed control algorithm enables
the system to converge to the maximum power point in
milliseconds.
2014
57.
Mode-Adaptive
Decentralized Control
for Renewable DC
Microgrid With
Abstract—A mode-adaptive decentralized control strategy
is proposed for the power management of a dc microgrid
with multiple renewable distributed generators and energy
storage systems. In the presented solution, the dc bus
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Enhanced Reliability
and Flexibility
voltage signal is used not only to enable power sharing
among different sources, but also to designate microgrid
operation modes and facilitate seamless mode transitions.
With this mode-adaptive operation mechanism, a greater
control freedom can be achieved than the conventional dc
voltage droop control scheme. More importantly, this
approach features fully self-disciplined regulation of
distributed converters without an extra control center or
communication link. Therefore, both reliability and
flexibility can be enhanced. Meanwhile, a novel mode
definition criterion is also provided to highlight the
special characteristics of the dc microgrid which is
different from an ac one. Three typical operation
conditions are summarized according to which type of
sources are dominating the power balance. Finally, the
effectiveness of the proposed technique is verified
experimentally based on a composite dc microgrid test
system.
58.
Model Reference
Adaptive Control-
Based Speed Control of
Brushless DC Motors
With Low-Resolution
Hall-Effect Sensors
Abstract—A control system with a novel speed estimation
approach based on model reference adaptive control
(MRAC) is presented for low cost brushless dc motor
drives with low-resolution hall sensors. The back EMF is
usually used to estimate speed. But the estimation result is
not accurate enough at low speeds because of the divided
voltage of stator resistors and too small back EMF.
Moreover, the stator resistor is always varying with the
motor’s temperature. A speed estimation algorithm based
on MRAC was proposed to correct the speed error
estimated by using back EMF. The proposed algorithm’s
most innovative feature is its adaptability to the entire
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speed range including low speeds and high speeds and
temperature and different motors do not affect the
accuracy of the estimation result. The effectiveness of the
algorithm was verified through simulations and
experiments.
59.
MPPT and Voltage
Balancing Control
With Sensing Only
Inductor Current for
Photovoltaic-Fed,
Three-Level, Boost-
TypeConverters
Abstract—In the literature, both photovoltaic voltage and
PV current need to be sensed to perform maximum power
point tracking (MPPT) control. For three-level boost
converter, both capacitor voltages need to be sensed and
an additional voltage balancing control loop is required to
balance the capacitor voltages. In this paper, the MPPT
control and the voltage balancing control with sensing
only inductor current is proposed. The provided
simulation and experimental results demonstrate the
proposed method.
2014
60.
New Extendable
Single-Stage Multi-
input DC–DC/AC
Boost Converter
Abstract—This paper presents a new extendable single-
stage multi-input dc–dc/ac boost converter. The proposed
structure comprises of two bidirectional ports in the
converter’s central part to interface output load and
battery storage, and several unidirectional input ports to
get powers from different input dc source. In fact, he
proposed topology consists of two sets of parallel dc– dc
boost converters, which are actively controlled to produce
two independent output voltage components. Choosing
two pure dc or two dc-biased sinusoidal values as the
converter reference voltages, situations of the converter
operating in two dc–dc and dc–ac modes are provided,
respectively. The proposed converter utilizes minimum
number of power switches and is able to step up the low-
level input dc voltages into a high-level output dc or ac
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voltage without needing any output filter. The converter
control system includes several current regulator loops for
input dc sources and two voltage regulator loops for
generating the desired output voltage components,
resulting in autonomously charging/discharging the
battery to balance the power flow. Due to the converter
inherent multi-input multi output control system, the
small signal model of the converter is extracted and then
the pole-placement control strategy via integral state
feedback is applied for achieving the converter control
laws. The validity and effectiveness of the proposed
converter and its control performance are verified by
simulation and experimental results.
61.
Novel Three-Port
Converter With High-
Voltage Gain
Abstract—In this paper, a novel three-port converter
(TPC) with high-voltage gain for stand-alone renewable
power system applications proposed. This converter uses
only three switches to achieve the power flow control.
Two input sources share only one inductor. Thus, the
volume can be reduced. Besides, the conversion ratio of
the converter is higher than other TPCs. Thus, the degree
of freedom of duty cycle is large. The converter can have
a higher voltage gain for both low-voltage ports with a
lower turns ratio and a reasonable duty ratio. The voltage
stress of switches is low; thus, conduction loss can be
further improved by adopting low Rds(on) switches.
Therefore, the converter can achieve a high conversion
ratio and high efficiency at the same time. The operation
principles, steady-state analysis, and control method of
the converter are presented and discussed. A prototype of
the proposed converter with a low input voltage 24 V for
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photovoltaic source, a battery port voltage 48 V, and an
output voltage 400 V is implemented to verify the
theoretical analysis. The power flow control of the
converter is also built and tested with a digital signal
processor.
62.
Optimal Trajectory
Control of LLC
Resonant Converters
for LED PWM
Dimming
Abstract—In this paper, a novel three-port converter
(TPC) with high-voltage gain for stand-alone renewable
power system applications is proposed. This converter
uses only three switches to achieve the power flow
control. Two input sources share only one inductor. Thus,
the volume can be reduced. Besides, the conversion ratio
of the converter is higher than other TPCs. Thus, the
degree of freedom of duty cycle is large. The converter
can have a higher voltage gain for both low-voltage ports
with a lower turns ratio and a reasonable duty ratio. The
voltage stress of switches is low; thus, conduction loss
can be further improved by adopting low Rds(on)
switches. Therefore, the converter can achieve a high
conversion ratio and high efficiency at the same time. The
operation principles, steady-state analysis, and control
method of the converter are presented and discussed. A
prototype of the proposed converter with a low input
voltage 24 V for photovoltaic source, a battery port
voltage 48 V, and an output voltage 400 V is implemented
to verify the theoretical analysis. The power flow control
of the converter is also built and tested with a digital
signal processor.
2014
63.
Parallel-Operation of
Discrete SiC BJTs in a
6-kW/250-kHz DC/DC
Abstract—This paper describes issues related to parallel
connection of SiC bipolar junction transistors (BJTs) in
discrete packages. The devices are applied in a high-
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Boost Converter frequency dc/dc boost converter where the switching
losses significantly exceed the conduction losses. The
design and construction of the converter is discussed with
special emphasis on successful parallel-operation of the
discrete BJTs. All considerations are experimentally
illustrated by a 6-kW, 250-kHz boost converter (300
V/600 V). A special solution for the base-drive unit, based
on the dual-source driver concept, is also shown in this
paper. The performance of this driver and the current
sharing of the BJTs are both presented. The power losses
and thermal performance of the parallel-connected
transistors have been determined experimentally for
different powers and switching frequencies. An efficiency
of 8.23% (±0.02%)was measured using a calorimetric
setup, while the maximum temperature difference among
the four devices is 12 ◦C.
64.
Scalability of Quasi-
Hysteretic FSM-Based
Digitally Controlled
Single-Inductor Dual-
String Buck LED
Driver to Multiple
Strings
Abstract—There has been growing interest in single-
inductor multiple-output (SIMO) dc–dc converters due to
its reduced cost and smaller form factor in comparison
with using multiple single output converters. An
application for such a SIMO-based switching converter is
to drive multiple LED strings in a multichannel LED
display. This paper proposes a quasi-hysteretic finite-state
machine-based digitally controlled single-inductor dual-
output buck switching LED driver operating in
discontinuous conduction mode (DCM) and extends it to
drive multiple outputs. Based on he time -multiplexing
control scheme in DCM, a theoretical upper limit of the
total number of outputs in a SIMO buck switching LED
driver for various backlight LED current values can be
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derived analytically. The advantages of the proposed
SIMO LED driver include reducing the controller design
complexity by eliminating loop compensation, driving
more LED strings without limited by the maximum LED
current rating, performing digital dimming with no
additional switches required, and optimization of local
bus voltage to compensate for variability of LED forward
voltage VF in each individual LED string with smaller
power loss. Loosely binned LEDs with arger VF variation
can, therefore, be used for reduced LED costs.
65.
Self-Compensation of
the Commutation
Angle Based on DC-
Link Current for High-
Speed Brushless DC
Motors With Low
Inductance
Abstract—As low-resolution position sensors, a high
placement accuracy of Hall-effect sensors is hard to
achieve. Accordingly, a commutation angle error is
generated. The commutation angle error will inevitably
increase the loss of the low inductance motor and even
cause serious consequence, which is the abnormal
conduction of a freewheeling diode in the unexcited phase
especially at high speed. In this paper, the influence of the
commutation angle error on the power loss for the high-
speed brushless dc motor with low inductance and non
ideal back electromotive force in a magnetically
suspended control moment gyro (MSCMG) is analyzed in
detail. In order to achieve low steady-state loss of an
MSCMG for space application, a raight forward method
of self-compensation of commutation angle based on dc-
link current is proposed. Both simulation and
experimental results confirm the feasibility and
effectiveness of the proposed method.
2014
66. Sensorless Control of
BLDC Motor Drive for
Abstract—This paper develops the brushless dc (BLDC)
motor sensorless control system for an automotive fuel
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an Automotive Fuel
Pump Using a
Hysteresis Comparator
pump. The sensorless techniques that are based on a
hysteresis comparator and a potential start-up method
with a high starting torque are suggested. The hysteresis
comparator is used to compensate for the phase delay of
the back EMFs due to a low-pass filter (LPF) and also
prevent multiple output transitions from noise or ripple in
the terminal voltages. The rotor position is aligned at
standstill for maximum starting torque without an
additional sensor and any information of motor
parameters. Also, the stator current can be easily adjusted
by modulating the pulse width of the switching devices
during alignment. Some experiments are implemented on
a single chip DSP controller to demonstrate the feasibility
of the suggested sensorless and start-up techniques.
67.
Single Power-
Conversion AC–DC
Converter With High
Power Factor and High
Efficiency
Abstract—This paper proposes a single power-conversion
ac–dc converter with high power factor and high
efficiency. The proposed converter is derived by
integrating a full-bridge diode rectifier and a series-
resonant active-clamp dc–dc converter. To obtain a high
power factor without a power factor correction circuit,
this paper proposes a novel control algorithm. The
proposed converter provides single power-conversion by
using the novel control algorithm for both power factor
correction and output control. Also, the active-clamp
circuit clamps the surge voltage of switches and recycles
the energy stored in the leakage inductance of the
transformer. Moreover, it provides zero-voltage turn-on
switching of the switches. Also, a series-resonant circuit
of the output-voltage doubler removes the reverse-
recovery problem of the output diodes. The proposed
2014
HYDERABAD | VIJAYAWADA | GUNTUR
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converter provides maximum power factor 0.995 and
maximum efficiency of 95.1% at the full load. The
operation principle of the converter is analyzed and
verified. Experimental results for a 400 W ac–dc
converter at a constant switching frequency of 50 kHz are
obtained to show the performance of the proposed
converter.
68.
Single-Phase High
Step-up Converter
With Improved
Multiplier Cell Suitable
for Half-Bridge-Based
PVInverter System
Abstract—In this paper, a single-phase high step-up
converter is proposed, designed not only to boost the
relatively low photovoltaic (PV) voltage to a high bus
voltage with high efficiency, but also to offer a neutral
point terminal for the half-bridge-based inverters. First
and foremost, two symmetrical high step-up converters
are combined and integrated to derive an improved
converter with neutral point terminal, which is strongly
expected for the half bridge-based inverters. Secondly, the
voltage gain of the converter is extended and the narrow
turn-off period is avoided by using the coupled inductor
multiplier. Furthermore, the coupled inductor multiplier
reduces the voltage stress of all the power devices. As a
result, the low voltage-rated power devices can be
employed to minimize the conduction losses. More
importantly, all the active switches work in the zero-
voltage-switching condition, which reduces the switching
losses effectively. All these factors improve the circuit
performance in the high step-up applications, especially
for the half-bridge based PV inverter systems. Finally, the
experimental results from a 500W, 48 –760 V prototype
at 100 kHz switching frequency are provided to verify the
effectiveness of the proposed converter. The highest
2014
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Accords IEEE & International Standards Mobile: 9603150547
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Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
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efficiency of the prototype is 96.5% and the efficiency is
over 94% in a wide load range.
69.
Soft-Switching
Current-Fed Push–Pull
Converter for 250-W
AC Module
Applications
Abstract—In this paper, a soft-switching single-inductor
push–pull converter is proposed. A push–pull converter is
suitable forlow-voltage photovoltaic ac module systems,
because the step-up ratio of the high-frequency
transformer is high, and the number of primary-side
switches is relatively small. However, the conventional
push–pull converter does not have high efficiency because
of high-switching losses due to hard switching and
transformer losses (copper and iron losses) as a result of
the high turn ratio of the transformer. In the proposed
converter, primary-side switches are turned ON at the
zero-voltage switching condition and turned OFF at the
zero-current switching condition through parallel
resonance between the secondary leakage inductance of
the transformer and a resonant capacitor. The proposed
push–pull converter decreases the switching loss using
soft switching of the primary switches. In addition, the
turn ratio of the transformer can be reduced by half using
a voltage-doubler of secondary side. The theoretical
analysis of the proposed converter is verified by
simulation and experimental results.
2014
70.
Space Vector
Pulsewidth Amplitude
Modulation for a
Buck–Boost
Voltage/Current Source
Inverter
Abstract—This paper proposes a space vector pulsewidth
amplitude modulation (SVPWAM) method for a buck–
boost voltage/current source inverter. For a voltage source
inverter, the switching loss is reduced by 87%, compared
to a conventional sinusoidal pulsewidth modulation
(SPWM) method. For a current source inverter, the
switching loss is reduced by 60%. In both cases, the
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
Uppal, Hyderabad | 4/13 Brodipet, Guntur | Benz Circle, Vijayawada
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power density is increased by a factor of 2 to 3. In
addition, it is also verified that the output harmonic
distortions of SVPWAM is lower than SPWM, by only
using one-third switching frequency of the latter one. A 1-
kW boost-converter-inverter prototype has been built and
tested using this modulation method. The maximum
overall system efficiency of 96.7% has been attained at
full power rating. The whole system power density
reaches 2.3 kW/L and 0.5 kW/lb. The numbers are
remarkable at this power rating.As a result, it is feasible to
use SVPWAM to make the buck–boost inverter suitable
for applications that require high efficiency, high power
density, high temperature, and low cost. Such applications
include electric vehicle motor drive or engine
starter/alternator.
71.
Supervisory Control of
an Adaptive-Droop
Regulated DC
Microgrid With Battery
Management
Capability
Abstract—DC power systems are gaining an increasing
interest in renewable energy applications because of the
good matching with dc output type sources such as
photovoltaic (PV) systems and secondary batteries. In this
paper, several distributed generators (DGs) have been
merged together with a pair of batteries and loads to form
an autonomous dc microgrid (MG). To overcome the
control challenge associated with coordination of multiple
batteries within one stand-alone MG, a double-layer
hierarchical control strategy was proposed. 1) The unit-
level primary control layer was established by an adaptive
voltage-droop method aimed to regulate the common bus
voltage and to sustain the states of charge (SOCs) of
batteries close to each other during moderate
replenishment. The control of every unit was expanded
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
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with unit-specific algorithm,i.e., finish-of-charging for
batteries and maximum powerpoint tracking (MPPT) for
renewable energy sources, with which a smooth online
overlap was designed and 2) the supervisory control layer
was designed to use the low-bandwidth communication
interface between the central controller and sources in
order to collect data needed for adaptive calculation of
virtual resistances (VRs) as well as transit criteria for
changing unit-level operating modes. A small-signal
stability for the whole range of VRs. The performance of
developed control was assessed through experimental
results.
72.
Switching Frequency
Derivation for the
Cascaded Multilevel
Inverter Operating in
Current Control Mode
Using Multiband
Hysteresis Modulation
Abstract—In this paper, a generalized expression of the
switching frequency is obtained for the cascaded H-bridge
multilevel inverter tracking a reference current. The
inverter is considered connected to the grid and operates
in current control mode using the generalized algorithm of
multiband hysteresis modulation. The results are derived
based on the time-domain current error dynamics which is
applicable for any levels of the cascaded multilevel
inverter. The generalized expression explicitly shows the
relationship between the instantaneous switching
frequency with the net hysteresis band, system
parameters, and number of levels. The expression can be
used for the determination of the net hysteresis band
required for a given desired effective maximum switching
frequency for the multiband hysteresis modulation. The
value of maximum, minimum, and average switching
frequencies can be obtained from the instantaneous
switching frequency expression. The results are useful for
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
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the design of the multiband hysteresis controller for
tracking of the desired reference current and can be used
to evaluate the performance characteristics of the
multilevel inverter. The simulation and experimental
verification of the results are obtained through single-
phase, three- and five-level cascaded H-bridge inverters.
73.
Switching Strategy
Based on Model
Predictive Control of
VSI to Obtain High
Efficiency and
Balanced Loss
Distribution
Abstract—This paper proposes the switching strategy
based on finite control set model predictive control (FCS-
MPC) method, to reduce switching losses and obtain
balanced loss distribution of the voltage-source inverters
(VSIs). Unlike the conventional FCSMPC method with
no explicit information of the reference voltage, the
developed voltage-based FCS-MPC scheme produces the
future reference voltage vector with the Lyapunov
function every sampling period. With information of both
the future reference voltage and the future load current
vectors, the proposed switching strategy instantaneously
determines one optimum clamped phase among the three
legs in the VSI every sampling period. By optimally
determining the clamping phase and its duration on the
basis of every sampling period, the proposed switching
strategy can successfully reduce the VSI switching losses.
In addition, the proposed switching method can yield a
balanced loss distribution among the switches in the VSI,
contrary to the conventional FCSMPC. The balanced loss
generation as well as the switching loss reduction by the
proposed method, which is optimal at the sampling period
scale, is directly incorporated with the platform of the
FCS-MPC algorithm, since the FCS-MPC operates on the
basis of the sampling period. Thus, the proposed
2014
HYDERABAD | VIJAYAWADA | GUNTUR
Accords IEEE & International Standards Mobile: 9603150547
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switching operation based on the voltage-based FCS-
MPC algorithm enables the future VSI output currents to
track the future reference current vector, as well as results
in the reduced switching losses and the balanced loss
performance.
74.
Synthesis of Canonical
Elements for Power
Processing in DC
Distribution Systems
Using Cascaded
Converters and Sliding-
Mode Control
Abstract—Switched power converters are used to
interface the dc output in modern distributed power
generation systems, which are usually aggregated to the
main grid to yield the necessary power using
interconnected modules. Synthesis, modeling, and
stability analysis of interconnected systems using
cascaded converters working under sliding-mode control
are considered in this paper. A systematic procedure to
synthesize cascaded connection of dc–dc boost converters
is introduced. The approach is based on making each
module to behave as a suitable canonical element for
power processing. Three different elements are
considered, which are the dc power gyrator, the dc
transformer, and the dc loss-free resistor. These canonical
elements are designed by means of a sliding-mode control
theory and then their dynamic behavior is studied in
detail.The sliding-mode conditions for each case are
derived in closed form to obtain design-oriented criteria
for selecting the parameters of the system. The
aforementioned canonical elements are compared to select
the most suitable one for a distributed power system.
Simulation results ensure the correctness of the proposed
approach. Experimental measurements corroborate the
theoretical predictions and the numerical simulations.
2014
75. The Transformerless Abstract—This paper presents a universal active filter for
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Single-Phase Universal
Active Power Filter for
Harmonic and Reactive
Power Compensation
harmonic and reactive power compensation for single-
phase systems applications. The proposed system is a
combination of parallel and series active filters without
transformer. It is suitable for applications where size and
weight are critical factors. The model of the system is
derived and it is shown that the circulating current
observedin the proposed active filter is an important
quantity that must be controlled. A complete control
system, including pulsewidth modulation (PWM)
techniques, is developed. Comparisons between the
structures are made from weighted total harmonic
distortion (WTHD). The steady-state analysis is also
presented in order to demonstrate the possibility to obtain
an optimum voltage angle reducing the current amplitude
of both series and parallel converters and, consequently,
the total losses of the system. Simulated and experimental
results validate the theoretical considerations.
2014
76.
Two- and Three-
Dimensional
Omnidirectional
Wireless Power
Transfer
Abstract—Non identical current control methods for 2-
and 3-D omnidirectional wireless power systems are
described. The omnidirectional power transmitter enables
acmagnetic flux to flowing all directions and coil
receivers to pick up energy in any position in the
proximity of the transmitter. It can be applied to wireless
charging systems for low-power devices such as radio-
frequency identification devices and sensors. Practical
results on 2-D and 3-D systems have confirmed the
omnidirectional power transfer capability.
2014
77.
Universal Digital
Controller for Boost
CCM Power Factor
Abstract—Continuous conduction mode power factor
correction (PFC) without input current measurement is a
step forward with respect to previously proposed PFC
2014
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Accords IEEE & International Standards Mobile: 9603150547
Vision Solutions
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Correction Stages
Based on Current
Rebuilding Concept
digital controllers. Inductor volt-second (vsL)
measurement in each switching period enables digital
estimation of the input current; however, an accurate
compensation of the small errors in the measured vsL is
required for the estimation to match the actual current.
Otherwise, they are accumulated every switching period
over the half-line cycle, leading to an appreciable current
distortion. A vsL estimation method isproposed,
measuring the input (vg ) and output voltage (vo).
Discontinuous conduction mode (DCM) occurs near input
line zero crossings and is detected by measuring the drain-
to-source MOSFET voltage vds. Parasitic elements cause
a small difference between the estimated voltage across
the inductor based on input and output voltage
measurements and the actual one, which must be taken
into account to estimate the input current in the proposed
sensorless PFC digital controller. This paper analyzes the
current estimation error caused by errors in the ON-time
estimation, voltage measurements, and the parasitic
elements. A new digital feedback control with high
resolution is also proposed. It cancels the difference
between DCM operation time of the real input current, (T
g DCM) and the estimated DCM time (T reb DCM).
Therefore, the current estimation is calibrated using
digital signals during operation in DCM. A fast feed
forward coarse time error compensation is carried out
with the measured delay of the drive signal, and a fine
compensation is achieved with a feedback loop that
matches the estimated and real DCM time. The digital
controller can be used in universal applications due to the
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ability of the DCM time feedback loop to autotune based
on the operation conditions (power level, input voltage,
output voltage. . .), which improves the operation range in
comparison with previous solutions. Experimental results
are shown for a 1-kW boost PFC converter over a wide
power and voltage range.
78.
Virtual Impedance-
Based Selective
Harmonic
Compensation (VI-
SHC) PWM for
Current Source
Rectifiers
Abstract—To mitigate the line current harmonics of a
highpower current source rectifier (CSR) system, the
selective harmonic elimination (SHE) scheme is
frequently used due to its low switching frequency and
superior harmonic performance. However, the SHE
scheme only focuses on the harmonics generated by the
converter itself. It cannot cope with the line current
harmonics caused by the background grid voltage
harmonics. In this paper, a selective harmonic
compensation scheme using the virtual impedance
concept (VI-SHC) is presented. This method compensates
for the preexisting grid background harmonics using only
the line current measurement, and provides superior line
current harmonic performance. The proposed method
does not require measuring the grid voltage harmonics
(which are typically low), does not rely on an accurate
CSR system model, and therefore is very robust for
practical implementation. This PWM control scheme has
been verified by real-time experiments on a CSR
prototype.
2014
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