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POWER ELECTRONICS
1. A Novel ZVT-ZCT-PWM Boost Converter
Abstract: 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 voltage
stress across the main and auxiliary components. The converter has a simple structure,
minimum number of components, and ease of control as well.
2. Analysis, Design, and Experimental Results of a Novel Soft-Switching
Snubberless Current-Fed Half-Bridge Front-End Converter-Based PV Inverter
Abstract: A new novel Snubberless current fed half-bridge front-end isolated dc/dc
converter-based inverter for photovoltaic applications. It is suitable for grid-tied (utility
interface) as well as off-grid (standalone) application based on the mode of control. This
converter attains clamping of the device voltage by secondary modulation, thus
eliminating the need of Snubber or active-clamp. Zero-current switching or natural
commutation of primary devices and zero-voltage switching of secondary devices is
achieved. Soft-switching is inherent owing to the proposed secondary modulation and is
maintained during wide variation in voltage and power transfer capacity and thus is
suitable for photovoltaic (PV) applications.
3. Bridgeless SEPIC Converter with a Ripple-Free Input Current
Abstract: Conventional power factor correction (PFC) single ended primary inductor
converter (SEPIC) suffers from high conduction loss at the input bridge diode. To solve
this problem, a bridgeless SEPIC converter with ripple-free input current is proposed. In
the proposed converter, the input bridge diode is removed and the conduction loss is
reduced. In addition, the input current ripple is significantly reduced by utilizing an
additional winding of the input inductor and an auxiliary capacitor. Similar to the
conventional PFC SEPIC converter, the input current in a switching period is
proportional to the input voltage and near unity power is achieved.
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4. High Performance Voltage Fed AC-DC Full-Bridge Single-Stage PFC with
Reduced DC Bus Capacitor
Abstract: Full-Bridge Single-Stage, FBSS, AC-DC converters allow regulating both the
output voltage and the input current that achieves a near sinusoidal waveform using only
the four bridge transistors. Independently of this feature, these converters still need to be
optimized in order to become an interesting and attractive solution for modern Switch
Mode Power Supplies with PFC function. One of the most important improvements
needed is the downsizing of the DC bus capacitor, with the inherent cost reduction. This
action introduces complex issues in the regulation of the input current and it is also
responsible for the generation of high output voltage ripple. These consists of a set of
power circuit optimizations and control techniques in a Full Bridge Single-Stage PFC
converter that solves the referred issues in order to enable the reduction of the DC bus
capacitor’s size and cost.
5. High-Efficiency Hybrid Full-Bridge–Half-Bridge Converter with Shared ZVS
Lagging Leg and Dual Outputs in Series
Abstract: A novel soft-switching hybrid converter combining the phase-shift full-bridge
(FB) and half-bridge (HB) LLC resonant converters’ configuration with shared zero-
voltage switching (ZVS) lagging leg is proposed to ensure the switches in the lagging leg
operating at fully ZVS condition. The dual outputs of the proposed hybrid FB–HB
converter are connected in series and the whole dc-output voltage can be regulated by the
PWM phase-shift control within the desired voltage range. A resonant circuit is used in
the secondary side of the FB converter to reset the primary current during the
freewheeling period, as well as to transfer more input energy and clamp secondary
rectifier voltage.
6. Low-Common Mode Voltage H-Bridge Converter with Additional Switch Legs
Abstract: H-bridge converter with additional switch legs (HA converter) and its offspring
circuit are proposed in this paper with the intent to reduce the common mode noise. The
proposed topology connects grounds of the input and output terminals, which gives zero
common mode current in the ideal case. The operation of the proposed circuit is flexible
and allows for the circuit to be capable of both ac–dc and dc–ac conversions. The
proposed topology is especially advantageous when it is applied to the photovoltaic
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power conditioning system in dc distribution system or stand-alone power system
because they include large stray capacitances and are prone to common mode EMI.
7. Analysis and Design of a Push–Pull Quasi Resonant Boost Power Factor
Corrector
Abstract: A novel power-factor corrector (PFC), which is mainly composed of two-phase
transition-mode (TM) boost-type power-factor correctors (PFCs) and a coupled inductor.
By integrating two boost inductors into one magnetic core, not only the circuit volume is
reduced, but also the operating frequency of the core is double of the switching
frequency. Comparing with single-phase TM boost PFC, both the input and output
current ripples of the proposed PFC can be reduced if the equivalent inductance of the
coupled inductor equals the inductance of single-phase TM boost PFC. Therefore, both
the power-factor value and the power density are increased. The proposed topology is
capable of sharing the input current and output current equally. The advantages of a TM
boost PFC, such as quasi-resonant (QR) valley switching on the switch and zero-current
switching (ZCS) of the output diode, are maintained to improve the overall conversion
efficiency.
8. A Modified High-Efficiency LLC Converter with Two Transformers for Wide
Input Voltage Range Applications
Abstract: A modified LLC converter with two transformers in series, which has four
operation configurations, covering the range of four times the minimum input voltage. To
optimize the proposed LLC converter in an attempt to achieve good efficiency, a
numerical method is developed based on the LLC converter’s steady-state equations. In
order to minimize the magnetizing current and thus minimize the conduction and core
losses, an optimal objective is proposed to find the maximum magnetizing inductance.
9. High-Efficiency Asymmetrical Half-Bridge Converter without Electrolytic
Capacitor for Low-Output-Voltage AC–DC LED Drivers
Abstract: Due to their high reliability and luminous efficacy, high-brightness light-
emitting diodes are being widely used in lighting applications, and therefore, their power
supplies are required to have also high reliability and efficiency. A very common
approach for achieving this in ac–dc applications is using a two-stage topology. The
power factor corrector boost converter operating in the boundary conduction mode is a
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very common converter used as first stage. It is normally designed without electrolytic
capacitors, improving reliability but also increasing the low-frequency ripple of the
output voltage. The asymmetrical half-bridge (AHB) is a perfect option for the second
stage as it has very high efficiency, it operates at constant switching frequency, and its
output filter is small.
10. Decoupling Capacitor Selection in DCM Flyback PV Micro-inverters
considering Harmonic Distortion
Abstract: Electrolytic capacitors as a decoupling reservoir restrict the lifetime of
photovoltaic (PV) micro-inverters. This has led to the development of several improved
decoupling circuits that can reduce the capacitor value to allow the use of non-electrolytic
types. The minimum decoupling capacitor value for the proper operation of discontinuous
conduction mode fly back PV micro-inverters is analyzed by taking into account the total
harmonic distortion (THD) and PV power utilization ratio. A decoupling capacitor
selection method for single-stage and two-stage fly-back inverters is proposed.
11. A Bridgeless Boost Rectifier for Low-Voltage Energy Harvesting Applications
Abstract: A single-stage ac–dc power electronic converter is proposed to efficiently
manage the energy harvested from electromagnetic microscale and mesoscale generators
with low-voltage outputs. The proposed topology combines a boost converter and a buck-
boost converter to condition the positive and negative half portions of the input ac
voltage, respectively. Only one inductor and capacitor are used in both circuitries to
reduce the size of the converter.
12. Design and Implementation of a Unity Power Factor Fuzzy Battery Charger
using an Ultrasparse Matrix Rectifier
Abstract: A novel unity power factor fuzzy battery charger conception based on an
ultrasparse matrix rectifier (USMR). The advantages of the proposed converter are low
harmonic distortion in absorbed currents and nearly unity power factor over a wide
operating output power range. Its circuit has only three switching components and low-
energy-conversion loss. This reduces the cost and enhances the system’s efficiency for
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high voltage battery. Thus, the proposed fuzzy logic controller improves the line power
quality and delivers admissible output power to the battery.
13. Novel Zero-voltage and Zero-current Switching (ZVZCS) PWM Three-level DC-
DC Converter Using Output Coupled Inductor
Abstract: A novel zero-voltage and zero-current switching (ZVZCS) pulse-width
modulation (PWM) half-bridge (HB) three-level (TL) dc/dc converter is proposed.
Compared with traditional ZVZCS PWM TL dc/dc converters, this converter does not
include auxiliary resonant circuits. It can achieve zero-voltage switching (ZVS) for the
leading switches and approximate zero-current switching (ZCS) for the lagging switches
with the aid of the transformer parasitic inductance, Snubber capacitors and tapped-
inductor type smoothing filter. This converter can reduce the voltage and current spikes
of the power switches as well as the primary circulating current loss effectively. The
operation principle of the novel converter and the soft-switching implementation
condition are analyzed according to equivalent circuits under different stages.
14. An Integrated Boost Resonant Converter for Photovoltaic Applications
Abstract: Mobile applications necessitate nowadays huge digital resources. Power
management of a digital systems-on-chip is based on dynamic voltage scaling. DC/DC
converters used to supply the digital system-on-a-chips are facing stringent constraints
with respect to load transients, line transients, and reference tracking. Hysteretic control
is known as the most convenient control scheme with a fair tradeoff between transient
performances, analog implementation and power consumption. Fixed-switching
frequency hysteretic control has been experimented as well as full sliding mode control.
Transient performances are reduced due to latencies introduced in the switching
frequency control. A new analog implementation of the sliding-mode control is presented
here with switching frequency control using a particular analog phase-locked loop but
preserve transient performances. The dc/dc converter is implemented in CMOS 130 nm.
The switching frequency range has been voluntarily limited and excludes the possible
integration of passive components.
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15. High-Efficiency Single Switch Single- Input Multiple-Output DC–DC Converter
Abstract: The aim of this study is to develop a high-efficiency single-input multiple-
output (SIMO) dc–dc converter. The proposed converter can boost the voltage of a low-
voltage input power source to a controllable high-voltage dc bus and middle-voltage
output terminals. The high-voltage dc bus can take as the main power for a high-voltage
dc load or the front terminal of a dc–ac inverter. Moreover, middle-voltage output
terminals can supply powers for individual middle-voltage dc loads or for charging
auxiliary power sources (e.g., battery modules). In this study, a coupled-inductor based
dc–dc converter scheme utilizes only one power switch with the properties of voltage
clamping and soft switching, and the corresponding device specifications are adequately
designed.
16. A Modified Single-Phase Quasi-Z-Source AC–AC Converter
Abstract: A modified single-phase quasi-Z-source ac–ac converter is proposed in this
paper. The proposed converter has the main features in that the output voltage can be
bucked or boosted and be both in-phase and out-of-phase with the input voltage. The
input voltage and output voltage share the same ground, the size of a converter is
reduced, and it operates in a continuous current mode. A safe-commutation strategy for
the modified single-phase quasi-Z-source ac–ac converter is used instead of a Snubber
circuit.
17. Improved Trans-Z-Source Inverter with Continuous Input Current and Boost
Inversion Capability
Abstract: This paper deals with a new family of high boost voltage inverters that improve
upon the conventional trans-Z-source and trans-quasi-Z-source inverters. The improved
trans-Z-source inverter provides continuous input current and a higher boost voltage
inversion capability. In addition, the improved inverter can suppress resonant current at
startup, which might destroy the device. In comparison to the conventional trans-Z-
source/-trans-quasi-Z-source inverters, for the same transformer turn ratio and input and
output voltages, the improved inverter has a higher modulation index with reduced
voltage stress on the dc link, lower current stress flow on the transformer windings and
diode, and lower input current ripple. In order to produce the same input and output
voltage with the same modulation index, the improved inverter uses a lower transformer
turn ratio compared to the conventional inverters. Thus, the size and weight of the
transformer in the improved inverter can be reduced.
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18. A High Step-Up Three-Port DC–DC Converter for Stand-Alone PV/Battery
Power Systems
Abstract: A three-port dc–dc converter integrating photovoltaic (PV) and battery power
for high step-up applications is proposed in this paper. The topology includes five power
switches, two coupled inductors, and two active-clamp circuits. The coupled inductors
are used to achieve high step-up voltage gain and to reduce the voltage stress of input
side switches. Two sets of active-clamp circuits are used to recycle the energy stored in
the leakage inductors and to improve the system efficiency. The operation mode does not
need to be changed when a transition between charging and discharging occurs.
Moreover, tracking maximum power point of the PV source and regulating the output
voltage can be operated simultaneously during charging/discharging transitions. As long
as the sun irradiation level is not too low, the maximum power point tracking (MPPT)
algorithm will be disabled only when the battery charging voltage is too high.
19. Analysis of Half-Wave Class DE Low dv/dt Rectifier at Any Duty Ratio
Abstract: Class DE low dv/dt rectifiers realize high-frequency high-efficiency
rectification and low-diode voltage stress which is no more than the output voltage. Half-
wave Class DE low dv/dt rectifier, which is one of the Class DE rectifiers, realizes the
common ground between the input port and the output port. The half-wave Class DE low
dv/dt rectifier is analyzed for any diode-ON-duty ratio. The equations of the waveforms,
the input and output powers, the current and voltage transfer functions, the current and
voltage stresses, the power-output capability, and the power conversion efficiencies are
obtained. The characteristics of the normalized output power, the normalized input
resistance and capacitance, the current and voltage transfer functions, and the power-
output capability are clarified as functions of the diode-ON-duty ratio.
20. An Analytical Steady-State Model of LCC type Series–Parallel Resonant
Converter with Capacitive Output Filter
Abstract: A piecewise analytical function is proposed and applied to investigate the
steady-state behavior of series–parallel resonant converter operated in a discontinuous
current mode. The converter shows two sequences of the equivalent circuits alternatively
operated in the discontinuous current mode with different output voltages. To get the
response time of current in one resonance, a successive solving process based on the
state-space method is presented analytically in each sequence. This solving process can
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describe the complicated behavior resulting from the load rectifier, which makes the
output capacitor appear or disappear several times in one switching period. By
introducing the output voltage coefficient and the principle of energy transmission
balance, the steady-state model is deduced afterward. This model is accurate and simple,
making it helpful to design and optimize the converter conveniently.
POWER SYSTEMS
1. Simulation of Transient Skin Effect of DC Railway System Based on
MATLAB/Simulink
Abstract: This technique for simulation of transient skin effect of the dc railway system
based on MATLAB/Simulink. The classic calculation of skin effect based on frequency
domain is not suitable for time-domain simulation. To develop a time-domain calculation
method which can be realized in MATLAB/Simulink, through the analysis of the step
series algorithm, results are applied to the calculation of frequency voltage signal and
compared with skin effect impedance of frequency. Accurate simulation of the transient
skin effect produces accurate modeling of the remote fault current. This is important for
the dc railway protection researchers to develop techniques for discriminating remote
short-circuits currents from locomotive starting currents.
2. A Sliding-Mode Duty-Ratio Controller for DC/DC Buck Converters with
Constant Power Loads
Abstract: Incorporating a medium-voltage DC (MVDC) integrated power system is a
goal for future surface combatants and submarines. In a MVDC shipboard power system,
DC/DC converters are commonly employed to supply constant power to electric loads.
These constant power loads have a characteristic of negative incremental impedance,
which may cause system instability during disturbances if the system is not properly
controlled. This paper proposes a sliding-mode duty-ratio controller (SMDC) for DC/DC
buck converters with constant power loads. The proposed SMDC is able to stabilize the
DC power systems over the entire operating range in the presence of significant
variations in the load power and input voltage. The proposed SMDC is validated by both
simulation studies in MATLAB/Simulink and experiments for stabilizing a DC/DC buck
converter with constant power loads.
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3. A Combination of Shunt Hybrid Power Filter and Thyristor Controlled Reactor
for Power Quality
Abstract: A combined system of a Thyristor-Controlled Reactor (TCR) and a Shunt
Hybrid Power Filter (SHPF) for harmonic and reactive power compensation. The SHPF
is the combination of a small rating Active Power Filter (APF) and a 5th harmonic tuned
LC Passive Filter. The tuned passive filter and the TCR form a Shunt Passive Filter (SPF)
to compensate reactive power. The small rating APF is used to improve filtering
characteristics of SPF and to suppress the possibility of resonance between the SPF and
line inductances. A PI controller was used and a triggering alpha was extracted using a
look up table to control the TCR. A nonlinear control of APF was developed for current
tracking and voltage regulation. The later is based on a decoupled control strategy, which
considers that the controlled system may be divided into an inner fast loop and an outer
slow one. Thus, an exact linearization control was applied to the inner loop and a
nonlinear feedback control law was used for the outer voltage loop.
4. Stability Enhancement of a PMSG-Based Offshore Wind Farm Fed to a Multi-
Machine System through an LCC-HVDC Link
Abstract: Adaptive-network-based fuzzy inference system (ANFIS) is an adaptation and
robustness method since it combines the advantages of artificial neural network (ANN)
and fuzzy logic controller (FLC). Besides, ANFIS is also a nonlinear controller that can
be used to improve stability of the studied system under different operating points. This
paper presents the stability-improvement results of an offshore wind farm (OWF) fed to a
multi-machine system through a high-voltage direct-current (HVDC) link based on line-
commutated converter (LCC). An effective control scheme using a designed ANFIS
damping controller at the inverter station of the HVDC link to achieve damping
improvement of the studied system is proposed. A frequency-domain scheme based on
Eigen value and root-loci technique is carried out to compare the effectiveness of the
proposed ANFIS control scheme and a modal-control designed PID damping controller.
5. Dynamic Averaged and Simplified Models for MMC-Based HVDC Transmission
Systems
Abstract: Voltage-source converter (VSC) technologies are rapidly evolving and
increasing the range of applications in a variety of fields within the power industry.
Existing two- and three-level VSC technologies are being superseded by the new modular
multilevel converter (MMC) technology for HVDC applications. The computational
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burden caused by detailed modeling of MMC–HVDC systems in electromagnetic
transient-type (EMT-type) programs complicates the simulation of transients when such
systems are integrated into large networks.
6. Coordinated Control and Energy Management of Distributed Generation
Inverters in a Micro-grid
Abstract: A microgrid consisting of different distributed generation (DG) units that are
connected to the distribution grid. An energy-management algorithm is implemented to
coordinate the operations of the different DG units in the microgrid for grid-connected
and islanded operations. The proposed microgrid consists of a photovoltaic (PV) array
which functions as the primary generation unit of the microgrid and a proton-exchange
membrane fuel cell to supplement the variability in the power generated by the PV array.
A lithium-ion storage battery is incorporated into the microgrid to mitigate peak demands
during grid-connected operation and to compensate for any shortage in the generated
power during islanded operation. The control design for the DG inverters employs a new
model predictive control algorithm which enables faster computational time for large
power systems by optimizing the steady-state and the transient control problems
separately.
7. Power Flow and Power Reduction Control Using Variable Frequency of Offshore
AC Grids
Abstract: An “integrated strategy” for connecting offshore wind farms to onshore grids,
an offshore AC grid is formed by interconnecting offshore wind farms and point-to-point
VSC-HVDC links using an AC network. The advantage of this strategy is that in the case
of a DC fault, AC circuit breakers are used to isolate the faulted HVDC link without the
need for DC circuit breakers. This paper presents a control system that regulates power
sharing between the HVDC links by varying the operating frequency of the offshore AC
grid. Primary and secondary power regulation controllers are designed to achieve
automatic power flow coordination between HVDC links. Increase in the offshore AC
grid frequency during onshore AC grid fault or DC fault signals power flow imbalance.
This signal is used to suppress the transient DC over-voltage through the coordination
control between the wind farm side converters of HVDC links and the power reduction
control of wind turbines.
8. Dynamic Stability Improvement of Four Parallel-Operated PMSG-Based
Offshore Wind Turbine Generators Fed to a Power System Using a STATCOM
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Abstract: The stability-improvement results of four parallel-operated offshore wind
turbine generators (WTGs) connected to an onshore power system using a static
synchronous compensator (STATCOM). The operating characteristics of each of the four
WTGs are simulated by a 5-MW wind permanent-magnet synchronous generator while
the onshore power system is simulated by a synchronous generator (SG) fed to an infinite
bus through two parallel transmission lines. A damping controller of the proposed
STATCOM is designed by using a pole-assignment approach to render adequate damping
to the dominant modes of the studied SG. A frequency-domain approach based on a
linearized system model using Eigen value analysis is performed while a time-domain
scheme based on a nonlinear system model subject to disturbances is also carried out.
RENEWABLE/SUSTAINABLE ENERGY 1. High Step-Up, High Efficiency Interleaved Converter with Voltage Multiplier
Module for Renewable Energy System
Abstract: A novel high step-up converter, which is suitable for renewable energy system
is proposed in this paper. Through a voltage multiplier module composed of switched
capacitors and coupled inductors, a conventional interleaved boost converter obtains high
step-up gain without operating at extreme duty ratio. The configuration of proposed
converter not only reduces the current stress but also constrains the input current ripple,
which decreases the conduction losses and lengthens the life time of input source. In
addition, Due to the lossless passive clamp performance, leakage energy is recycled to
the output terminal. Hence, large voltage spikes across the main switches are alleviated
and the efficiency is improved. Even the low voltage stress makes the low-voltage-rated
MOSFETs can be adopted for reductions of conduction losses and cost.
2. A Comparative Study on Maximum Power Point Tracking Techniques for
Photovoltaic Power Systems
Abstract: A comprehensive review of the maximum power point tracking (MPPT)
techniques applied to photovoltaic (PV) power system. A good number of publications
report on different MPPT techniques for a PV system together with implementation. But,
confusion lies while selecting a MPPT as every technique has its own merits and
demerits. Hence, a proper review of these techniques is essential. Unfortunately, very few
attempts have been made in this regard, excepting two latest reviews on MPPT. Since,
MPPT is an essential part of a PV system, extensive research has been revealed in recent
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years in this field and many new techniques have been reported to the list since then. In
this paper, a detailed description and then classification of the MPPT techniques have
made based on features, such as number of control variables involved, types of control
strategies employed, types of circuitry used suitably for PV system and practical/
commercial applications.
3. A New Hybrid Modular Multilevel Converter for Grid Connection of Large Wind
Turbines
Abstract: The trend towards multi-megawatt (multi-MW) wind turbines and the
increasing interest in direct-drive variable-speed wind energy systems have made
multilevel converters a promising candidate for large wind energy conversion systems. A
new hybrid modular multilevel converter for interfacing a full-scale, permanent magnet
synchronous generator (PMSG)-based direct-drive variable-speed wind energy
conversion system (WECS). The proposed hybrid converter, which is used on the grid
side of the system, consists of a three-level modular multilevel converter (MMC) in series
connection with three H-bridge modules. The generator-side converter is based on a
conventional three-level neutral-point-clamped converter. The proposed hybrid converter,
as opposed to the existing full-scale multilevel converter-based wind energy systems,
provides structural modularity and higher dc-bus voltage utilization. These formulate and
analyze the internal dynamics of the proposed hybrid converter including the circulating
currents and the capacitor voltage ripples. The ac components of the circulating currents,
if not properly reduced, increase the amplitude of the capacitor voltage ripples, rating
values of the converter components, and losses. Based on the analysis, closed-loop
circulating current and capacitor voltage ripple reduction techniques are developed. The
reduction of capacitor voltage ripples help reduce the capacitor value.
4. A Novel Operation and Control Strategy for a Standalone Hybrid Renewable
Power System
Abstract: A novel operation and control strategy for a renewable hybrid power system
for a standalone operation. The proposed hybrid system consists of a wind turbine, a fuel
cell, electrolyze, a battery storage unit, and a set of loads. The overall control strategy is
based on a two-level structure. The top level is the energy management and power
regulation system. Depending on wind and load conditions, this system generates
reference dynamic operating points to low level individual subsystems. The energy
management and power regulation system also controls the load scheduling operation
during unfavorable wind conditions under inadequate energy storage in order to avoid a
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system blackout. Based on the reference dynamic operating points of the individual
subsystems, the local controllers control the wind turbine, fuel cell, electrolyses, and
battery storage units.
5. Dynamic Modeling and Control of Interleaved Flyback Module Integrated
Converter for PV Power Applications
Abstract: For PV applications, the interleaved flyback module integrated converters
(IFMIC) operating in continuous conduction mode (CCM) shows the advantages of high
power density, low voltage and current stresses, and low electromagnetic interference,
but demonstrates a difficult control problem compared to the discontinuous conduction
mode (DCM). The control issues and presents detailed modeling, in-depth dynamic
analysis, and a two-step controller design approach for IFMIC systems operating in
CCM. The proposed modeling approach is based on the fourth-order system considering
the dynamics of the output CL filter. This realistic fourth-order system modeling shows
the presence of a resonant peak at a certain frequency, which can cause phase loss and
constraints of system bandwidth. A decoupled two-step controller design approach is thus
proposed to simplify the modeling and control synthesis in the IFMIC development. The
decoupled controller consists of a PI controller followed by a lag term for mitigating the
effect of the resonant peak.
INDUSTRIAL ELECTRONICS 1. A New Interleaved Three-Phase Single-Stage PFC AC–DC Converter
Abstract: A new interleaved single-stage ac–dc converter is proposed in this paper to
reduce line current harmonics while achieving power factor correction (PFC). The
proposed rectifier can produce input currents that do not have dead band regions with
high PFC, operate with a continuous output current, and minimize the input
electromagnetic interference filter size.
2. Cascade Cockcroft– Walton Voltage Multiplier Applied to Transformerless High
Step-Up DC–DC Converter
Abstract: This paper proposes a high step-up dc-dc converter based on the Cockcroft-
Walton (CW) voltage multiplier without a step-up transformer. Providing continuous
input current with low ripple, high voltage ratio, and low voltage stress on the switches,
diodes, and capacitors, the proposed converter is quite suitable for applying to low-input-
level dc generation systems. Moreover, based on the n-stage CW voltage multiplier, the
proposed converter can provide a suitable dc source for an n + 1-level multilevel inverter.
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In this paper, the proposed control strategy employs two independent frequencies, one of
which operates at high frequency to minimize the size of the inductor while the other one
operates at relatively low frequency according to the desired output voltage ripple.
3. A New ZCS-PWM Full-Bridge Dc-Dc Converter with Simple Auxiliary Circuits
Abstract: A new soft-switching PWM full-bridge converter is proposed in this paper. The
outstanding feature of the new converter is that it allows its main power switches to
operate with zero current switching (ZCS) and with fewer conduction losses than
conventional full-bridge converters. This is achieved by using two very simple active
auxiliary circuits – one active, one passive.
4. High-Efficiency LED Driver without Electrolytic Capacitor for Street Lighting
Abstract: High-brightness light-emitting diodes (LEDs) are considered as a remarkable
lighting device due to their high reliability, chromatic variety, and increasing efficiency.
As a consequence, a high number of solutions for supplying LED strings are coming out.
One-stage solutions are cost effective, but their efficiency is low as they have to fulfill
several purposes with only one converter: power factor correction (PFC), galvanic
isolation (in some cases), and current regulation. Two-stage and three-stage solutions
have higher efficiency as each stage is optimized for just one or two tasks, and they are
the preferred option when supplying several strings at the same time. Nevertheless, due to
their higher cost in comparison to one-stage solutions, they are used when high
efficiency, high performance, and the possibility of supplying several strings are the main
concerns. In addition, they are also used when high reliability is needed and electrolytic
capacitors cannot be used.
5. A Modified Three-Phase Four-Wire UPQC Topology with Reduced DC-Link
Voltage Rating
Abstract: The unified power quality conditioner (UPQC) is a custom power device,
which mitigates voltage and current-related PQ issues in the power distribution systems.
In this paper, a UPQC topology for applications with non-stiff source is proposed. The
proposed topology enables UPQC to have a reduced dc-link voltage without
compromising its compensation capability. This proposed topology also helps to match
the dc-link voltage requirement of the shunt and series active filters of the UPQC. The
topology uses a capacitor in series with the interfacing inductor of the shunt active filter,
and the system neutral is connected to the negative terminal of the dc-link voltage to
avoid the requirement of the fourth leg in the voltage source inverter (VSI) of the shunt
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active filter. The average switching frequency of the switches in the VSI also reduces;
consequently the switching losses in the inverters reduce.
6. Analysis and Design of a Multi-output Converter Using Asymmetrical PWM
Half-Bridge Flyback Converter Employing a Parallel–Series Transformer
Abstract: A multi-output converter using an asymmetrical pulse width modulation half-
bridge flyback topology employing a parallel–series-connected transformer. Compared to
conventional multi-output topologies, the proposed converter operates using a single-
output controller without the need for additional control loops and devices. In order to
solve the cross-regulation problem, the output stages of the proposed converter are
stacked in series. In addition, the voltage regulation of the proposed multi-output
converter is improved through the analysis of its resonant characteristics under load
variations and minimizing the secondary conduction loss. The proposed multi-output
converter shows excellent performance in terms of its output regulation from no-load to
full-load conditions and good cross regulation under high output currents.
7. Analysis and Design of Phase-Shifted Dual H-Bridge Converter with a Wide ZVS
Range and Reduced Output Filter
Abstract: A phase-shifted dual H-bridge converter, which can solve the drawbacks of
existing phase-shifted full-bridge converters such as narrow zero-voltage-switching
(ZVS) range, large circulating current, large duty-cycle loss, and serious secondary-
voltage overshoot and oscillation, is analyzed and evaluated. The proposed topology is
composed of two symmetric half-bridge inverters that are placed in parallel on the
primary side and are driven in a phase-shifting manner to regulate the output voltage. At
the rectifier stage, a center-tap-type rectifier with two additional low-current-rated diodes
is employed. This structure allows the proposed converter to have the advantages of a
wide ZVS range, no problems related to duty-cycle loss, no circulating current, and the
reduction of secondary-voltage oscillation and overshoot. Moreover, the output filter’s
size becomes smaller compared to the conventional phase-shift full-bridge converters.
8. Closed-loop Control of DC-DC Dual Active Bridge Converters Driving Single-
Phase Inverters
Abstract: A solid state transformer (SST) is a high-frequency power electronic converter
that is used as a distribution power transformer. A common three-stage configuration of
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an SST consists of ac-dc rectifier, isolated dc-dc dual-active-bridge (DAB) converter, and
dc-ac inverter. This work addresses the controller design issue for a dc-dc DAB converter
when driving a regulated single-phase dc-ac inverter. Since the switching frequency of
the inverter stage is much higher than that of the DAB stage, the single-phase inverter is
modeled as a double-line-frequency current sink. The effect of 120-Hz current by the
single-phase inverter is studied. The limitation of a PI controller, low gain at 120 Hz, is
investigated. Two methods are proposed to improve the regulation of the output voltage
of DAB converters.
9. A Novel Flyback-Based Input PFC Stage for Electronic Ballasts in Lighting
Applications
Abstract: An electronic driver for public lighting systems. The input stage is based on the
integration of two flyback converters with different polarities, in order to avoid the use of
the input diode bridge rectifying stage. The output stage is a boost converter with an
output current control. The proposed circuit is introduced and analyzed, and a design
example for a 50-W light-emitting diode lamp is presented. The most relevant simulation
and experimental results are also shown, in order to validate the idea. A comparison in
terms of efficiency for the input stage is carried out between the proposed topology and
the conventional flyback converter, showing an efficiency enhancement in the proposed
converter. However, the most important advantage of the proposed converter is outlined
in the final part of this paper. This advantage comes from the avoidance of the input
diode bridge, thus enabling the bidirectional power flow at the input stage. Therefore, the
topology can be used to deliver energy into the power grid. In recent lighting
applications, the use of micro renewable generators in lighting points has made the use of
special electronics to handle the energy flows in the ballast necessary.
10. A Novel Integrated Buck–Flyback Non-isolated PFC Converter with High
Power Factor
Abstract: A novel integrated buck–flyback non-isolated power factor (PF) correction
(PFC) converter is proposed in this paper. This new converter is an inherent integration
of a buck converter and a flyback converter, which operates in either flyback mode or
buck mode according to whether the input voltage is lower or higher than the output
voltage. In this way, the dead zones of ac input current in traditional buck PFC converter
are eliminated. Therefore, the proposed integrated buck–flyback non-isolated PFC
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converter can achieve high PF under universal ac input range, and its input current
harmonics can easily meet the limits.
11. A High Frequency Dual-Channel Isolated Resonant Gate Driver with Low Gate
Drive Loss for ZVS Full-Bridge Converters
Abstract: As switching frequency increases, to reduce the gate drive loss combined with
the Zero-Voltage-Switching (ZVS) technique is meaningful for the widely used Full-
Bridge (FB) converters. A dual-channel isolated Resonant Gate Driver (RGD) is
proposed in this paper. The proposed RGD is able to provide two isolated complementary
drive signals for a pair of power MOSFETs in one bridge leg. The proposed RGD
reduces about 79 % gate drive loss compared to the conventional Voltage Source Driver
(VSD). In addition, the negative gate drive voltage provided by the proposed RGD
prevents the false trigger problem in the FB converters.
12. Zero-Voltage Switching Multi-Output Flyback Converter with Integrated
Auxiliary Buck Converter
Abstract: A new multi-output converter. It consists of half-bridge inverter in primary
side, and flyback rectifier which is integrated with auxiliary buck converter in secondary
side. The primary switches control the main output voltage and the secondary
synchronous switches control the auxiliary output voltage. The main advantages of the
proposed converter are that the transformer size can be reduced due to the lower
magnetizing offset current, all the switches including synchronous ones can achieve the
zero-voltage switching (ZVS).
ELECTRICAL MACHINE DRIVES
1. An Adjustable Speed PFC Bridgeless Buck-Boost Converter Fed BLDC Motor
Drive
Abstract: A PFC (Power Factor Corrected) BL (Bridgeless) buck-boost converter fed
BLDC (Brushless Direct Current) motor drive as a cost effective solution for low power
applications. An approach of speed control of BLDC motor by controlling the DC link
voltage of VSI (Voltage Source Inverter) is used with a single voltage sensor. This
facilitates the operation of VSI at fundamental frequency switching by using the
electronic commutation of BLDC motor which offers reduced switching losses. A
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bridgeless configuration of buck-boost converter is proposed which offers elimination of
DBR (Diode Bridge Rectifier), thus reduces the conduction losses associated with it.
2. Digital Control Strategy for Four Quadrant Operation of Three Phase BLDC
Motor with Load Variations
Abstract: Brushless DC (BLDC) motor drives are becoming more popular in industrial,
traction applications. This makes the control of BLDC motor in all the four quadrants
very vital. This paper deals with the digital control of three phase BLDC motor. The
motor is controlled in all the four quadrants without any loss of power; in fact energy is
conserved during the regenerative period.
3. A Driver for the Single-Phase Brushless DC Fan Motor with Hybrid Winding
Structure
Abstract: A novel driver for a single-phase brushless dc fan motor with a hybrid
series/parallel winding structure. The winding symbols and directions of the hybrid motor
stator structure are defined, and the winding steps for the proposed series/parallel
winding are explained. An adequate inverter driving circuit, which is capable to
simultaneously obtain the advantages of the hybrid structure, is also discussed. At last,
the overall system of this hybrid brushless dc motor with the proposed driving circuit is
then implemented to verify the performance of the proposed driver and structure.