Search results for: H.S.H. Chung

Items from 1 to 20 out of 37 results

article

A Novel Set-Based Particle Swarm Optimization Method for Discrete Optimization Problems

Wei-Neng Chen, Jun Zhang, H.S.H. Chung, Wen-Liang Zhong, more

IEEE Transactions on Evolutionary Computation > 2010 > 14 > 2 > 278 - 300

Particle swarm optimization (PSO) is predominately used to find solutions for continuous optimization problems. As the operators of PSO are originally designed in an n-dimensional continuous space, the advancement of using PSO to find solutions in a discrete space is at a slow pace. In this paper, a novel set-based PSO (S-PSO) method for the solutions of some combinatorial optimization problems (COPs)...

chapter

Active cancellation of capacitor ESR and ESL effects for improving converter transient and steady-state response

H.S.H. Chung, W.T. Yan, A.K.T. Sung

2009 IEEE Energy Conversion Congress and Exposition > 723 - 730

2009 IEEE Energy Conversion Congress and Exposition (ECCE 2009)

An active cancellator that can reduce the capacitor equivalent series resistance (ESR) and equivalent series inductance (ESL) effects and provide capacitor current information is presented. The concept is based on connecting a linear voltage source in series with the capacitor to counteract the voltage drops caused by the ESR and ESL. Due to a reduction in the effective ESR and ESL, the damped resonant...

chapter

Passive lossless snubber with minimum voltage and current stress for boost PFC

R.T.H. Li, H.S.H. Chung, A.K.T. Sung

2009 IEEE Energy Conversion Congress and Exposition > 940 - 947

2009 IEEE Energy Conversion Congress and Exposition (ECCE 2009)

A passive lossless snubber for boost power factor corrector (PFC) is presented. This snubber has several advantages. First, it does not introduce extra voltage and current stress on the main switch. Second, it provides soft-switching conditions for the main switch over wide input and load range. Third, it limits the turn-on current of the main switch resulting from the reverse recovery current of...

chapter

Dynamic control of a light-emitting diode system based on the general photo-electro-thermal theory

Y.X. Qin, D.Y. Lin, H.S.H. Chung, W. Yan, more

2009 IEEE Energy Conversion Congress and Exposition > 2815 - 2820

2009 IEEE Energy Conversion Congress and Exposition (ECCE 2009)

This paper presents a dynamic thermal model of a LED system and a control strategy for optimal power point tracking (OPPT). The control strategy is based on the general theory which links the photometric, electric and thermal behaviors of LEDs together. The control implementation enables the optimal operating of the LED systems to be determined dynamically. By measuring the ambient temperature and...

chapter

Constant-frequency hysteresis current control of grid-connected VSI without bandwidth control

C.N.M. Ho, V.S.P. Cheung, H.S.H. Chung

2009 IEEE Energy Conversion Congress and Exposition > 2949 - 2956

2009 IEEE Energy Conversion Congress and Exposition (ECCE 2009)

The theory, design, and implementation of a constant-frequency hysteresis current control for grid-connected voltage source inverter (VSI) is presented. The proposed control technique retains the benefit of the hysteresis control having fast dynamic response and tackles the drawback of the standard hysteresis control having variable switching frequency. The concept is based on predicting the current...

chapter

A ZCS full-bridge converter without voltage over-stress on the switches

Xin Zhang, H.S.H. Chung, Xinbo Ruan, A. Ioinovici

2009 IEEE Energy Conversion Congress and Exposition > 1991 - 1998

2009 IEEE Energy Conversion Congress and Exposition (ECCE 2009)

A current-driven soft-switched full-bridge converter is presented. It contains a snubber formed by a switched-capacitor circuit and a resonant inductor, connected in the primary side. The transformer leakage inductance is used as a part of the resonant circuit. All the main switches are turned-on/off with zero-current-switching (ZCS), and the switches in the snubber are zero-voltage-switched (ZVS)...

chapter

A passive lossless snubber cell with minimum stress and wide soft-switching range

R.T.H. Li, H.S.H. Chung

2009 IEEE Energy Conversion Congress and Exposition > 685 - 692

2009 IEEE Energy Conversion Congress and Exposition (ECCE 2009)

A passive lossless snubber cell and its dual structure for reducing the switching loss of a range of switching converters are presented. The proposed snubber cell has several advantages over existing snubbering techniques. First, it provides zero-current-switching (ZCS) and zero-voltage-switching (ZVS) conditions for turning on and off, respectively, the switch over a wide load range. Second, it does...

chapter

Modeling and Analysis of a Current-Fed ZCS Full-Bridge DC/DC Converter with Adaptive Soft-Switching Energy

H. Wang, H.S.H. Chung, S. Tapuchi, A. Ioinovici

2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition > 1410 - 1416

2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition (APEC)

A full dc and ac analysis of a previous proposed boost-type-input soft-switching full-bridge converter is presented. The primary-side switches turn-on/off under a zero-current condition (ZCS). The soft-switching is realized by using a simple snubber, formed by two uni-directional switches and a resonant capacitor, in the primary side. The snubber's switches commute under a zero-voltage condition....

article

A ZCS Current-Fed Full-Bridge PWM Converter With Self-Adaptable Soft-Switching Snubber Energy

Huai Wang, Qian Sun, H.S.H. Chung, S. Tapuchi, more

IEEE Transactions on Power Electronics > 2009 > 24 > 8 > 1977 - 1991

A new soft-switched, current-driven full-bridge converter is presented. The structure utilizes a simple snubber formed by two unidirectional switches and a capacitor to realize soft-switching operation over a wide line and load range. All primary-side switches are operated with zero-current switching (ZCS) and the snubber switches are operated with zero-voltage switching. The energy used for soft-switching...

chapter

Current source ballast for high power lighting emitting diodes without electrolytic capacitor

Y.X. Qin, H.S.H. Chung, D.Y. Lin, S.Y.R. Hui

2008 34th Annual Conference of IEEE Industrial Electronics > 1968 - 1973

IECON 2008 - 34th Annual Conference of IEEE Industrial Electronics Society

An LED driver requiring no electrolytic capacitor in the whole power conversion process is presented. It consists of two power conversion stages. The first stage is a buck converter operating in discontinuous capacitor voltage mode, so that the input current is continuous. It is used to deliver a regulated current for the second stage. The second stage is a current-fed inverter, in which the semiconductor...

chapter

Effective standby power reduction using non-dissipative single-sensor method

S.Y.R. Hui, H.S.H. Chung, D.Y. Qiu

2008 IEEE Power Electronics Specialists Conference > 678 - 684

2008 IEEE Power Electronics Specialists Conference

This paper presents an implementation of the "single-sensor" method for controlling a power factor correction (PFC) circuit. The method eliminates lossy resistive feedback by deriving control variables such as the input and output voltages of the power converter via the switching action of the power MOSFET of the power converter. It can be applied directly to control the PFC circuit under...

chapter

A ZCS full-bridge PWM converter with self-adaptable soft-switching snubber energy

Qian Sun, Huai Wang, R.T.H. Li, H.S.H. Chung, more

2008 IEEE Power Electronics Specialists Conference > 3001 - 3007

2008 IEEE Power Electronics Specialists Conference

A new soft-switching full-bridge current-driven DC-DC converter is proposed for high voltage and high power applications: its power transistors turn-on/off with ZCS, what is suitable for IGBT switches. An active snubber formed by two active switches and one capacitor is inserted in the primary side of the converter. The snubber's accumulated energy is proportional to the input current, what allows...

chapter

Optimization of power electronic circuits using ant colony system

Jun Zhang, H.S.H. Chung, A.W.L. Lo, Tao Huang

2008 IEEE Power Electronics Specialists Conference > 2396 - 2402

2008 IEEE Power Electronics Specialists Conference

Ant colony optimization (ACO) is typically used to search paths through graphs. The concept is based on simulating the behavior of ants in finding paths from the colony to food. Its searching mechanism is applicable for optimizing electric circuits with components, like resistors and capacitors, available in discrete values. In this paper, an extended ACO (eACO) that can search the optimal values...

chapter

Fixed-frequency boundary control of buck converters with second-order switching surface

W.T. Yan, H.S.H. Chung, K. Au, C.N.M. Ho

2008 IEEE Power Electronics Specialists Conference > 629 - 635

2008 IEEE Power Electronics Specialists Conference

A fixed-frequency boundary control of buck converter will be presented in this paper. The methodology is based on integrating the concept of variable hysteresis into the previously proposed boundary control technique with second-order switching surface. The switching frequency is maintained constant by using a frequency-to-voltage converter and comparing its output with a reference voltage to control...

chapter

Application of hybrid PWM and passive resonant snubber for grid-connected CSI

R.T.H. Li, H.S.H. Chung

2008 IEEE Power Electronics Specialists Conference > 837 - 843

2008 IEEE Power Electronics Specialists Conference

A hybrid pulsewidth modulation (PWM) scheme that hybridizes the advantages of unipolar switching scheme (USS) and bipolar switching scheme (BSS) for grid-connected current source inverter (CSI) is presented. The former switching scheme has the advantage of low switching losses while the latter one has the advantage of generating output with low total harmonic distortion (THD). The inverter bridge...

article

Design and Implementation of a Fast Dynamic Control Scheme for Capacitor-Supported Dynamic Voltage Restorers

C.N.-m. Ho, H.S.H. Chung, K.T.K. Au

IEEE Transactions on Power Electronics > 2008 > 23 > 1 > 237 - 251

This paper presents a fast dynamic control scheme for capacitor-supported single-phase dynamic voltage restorers (DVRs) for inductive loads. The scheme consists of two main control loops as inner and outer loops. The inner loop is used to dictate the gate signals for the switches in the DVR. It is based on the boundary control method with the second-order switching surface. The load voltage can ideally...

chapter

Fast Dynamic Control Scheme for Capacitor-Supported Dynamic Voltage Restorers: Design Issues, Implementation and Analysis

C.N.M. Ho, H.S.H. Chung

2007 IEEE Power Electronics Specialists Conference > 3066 - 3072

IEEE 38th Annual Power Electronics Specialists Conference

The design issues, implementation procedures and system analysis for a fast transient control scheme for single-phase capacitor-supported dynamic voltage restorers (DVR) are presented in this paper. The proposed control scheme includes two control loops as inner and outer loops. The inner control loop is used to dictate the gate signals for the switches in the DVR by using the boundary control with...

chapter

Strategy for Current Harmonic Reduction of PFC with Boundary Control Using Second-order Switching Surface

C.N.M. Ho, K.T.K. Au, H.S.H. Chung

2007 IEEE Power Electronics Specialists Conference > 1319 - 1325

IEEE 38th Annual Power Electronics Specialists Conference

The difference between the fast dynamics associated with the input current of power factor correctors (PFCs) and the slow dynamics associated with their output voltage is typically exploited by using multiple control loops. The overall dynamic response is generally limited by the output voltage regulation loop. Research into an analogy-based controller for PFCs is at a slow pace. This paper applies...

chapter

A ZCS Isolated Full-Bridge Boost Converter with Multiple Inputs

A.S.W. Leung, H.S.H. Chung, T. Chan

2007 IEEE Power Electronics Specialists Conference > 2542 - 2548

IEEE 38th Annual Power Electronics Specialists Conference

A modular-based, zero-current-switched (ZCS), isolated full-bridge boost converter with multiple inputs is presented. By connecting a simple auxiliary circuit, between the full-bridge input and the input choke, in each module, the transformer leakage inductance and output capacitance of the switching devices are used to create a quasi-resonant path for facilitating ZCS of all full-bridge switching...

chapter

Iterative Behavioral Modeling of Charge-Pump Based Electronic Ballast-Fluorescent lamp System

P.W. Tarn, H.S.H. Chung, S.Y.R. Hui

2007 IEEE Power Electronics Specialists Conference > 2279 - 2286

IEEE 38th Annual Power Electronics Specialists Conference

A new behavioral model for analyzing the charge- pump based ballast is proposed in this paper. A detailed model derivation is presented and the model is applied to analyze a ballast system of a 16 W compact fluorescent lamp (CFL) as an illustration. The ballast of the CFL consists of a self-oscillatory driven inverter stage and a charge-pump circuitry. It is shown that the model can give a comprehensive...

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Keywords

SWITCHING CONVERTORS (20)
BOUNDARY CONTROL (12)
SECOND-ORDER SWITCHING SURFACE (9)
DYNAMIC RESPONSE (8)
SWITCHES (8)
CAPACITORS (7)
INVERTORS (7)
SNUBBERS (7)
VOLTAGE CONTROL (7)
ZERO CURRENT SWITCHING (7)
BRIDGE CIRCUITS (6)
POWER CONVERTORS (6)
INDUCTORS (5)
INVERTERS (5)
POWER CAPACITORS (5)
POWER FACTOR CORRECTION (5)
VOLTAGE 110 V (5)
CONTINUOUS CONDUCTION MODE (4)
CONVERTERS (4)
DC-DC POWER CONVERTORS (4)
POWER FACTOR CORRECTOR (4)
PWM POWER CONVERTORS (4)
SWITCHING LOSS (4)
VOLTAGE 15 KV (4)
ZERO VOLTAGE SWITCHING (4)
CHROMIUM (3)
CONTROL SYSTEMS (3)
DISCONTINUOUS CONDUCTION MODE (3)
FAST DYNAMIC CONTROL SCHEME (3)
INVERTER (3)
LAMP ACCESSORIES (3)
POWER 5 KW (3)
POWER SUPPLY QUALITY (3)
STATE TRAJECTORY MOVEMENT (3)
SWITCHING CONVERTERS (3)
SWITCHING FREQUENCY (3)
VOLTAGE (3)
VOLTAGE 530 V (3)
ZERO-CURRENT SWITCHING (3)
1 KW (2)
100 W (2)
AC/DC CONVERSION (2)
BOUNDARY CONTROL METHOD (2)
BUCK CONVERTERS (2)
CAPACITOR SWITCHING (2)
CAPACITOR-SUPPORTED DYNAMIC VOLTAGE RESTORERS (2)
CONSTANT SWITCHING FREQUENCY (2)
CONTROL SYSTEM SYNTHESIS (2)
DIGITAL CONTROL (2)
DYNAMIC RESPONSES (2)
ELECTRIC CURRENT CONTROL (2)
ELECTROLYTIC CAPACITORS (2)
FREQUENCY 60 HZ (2)
HARMONIC ANALYSIS (2)
HARMONIC DISTORTION (2)
HYSTERESIS (2)
INDUCTANCE (2)
LIGHT EMITTING DIODES (2)
LIGHTING CONTROL (2)
MAXIMUM VOLTAGE INJECTION (2)
MINIMUM ENERGY INJECTION (2)
NONLINEAR INDUCTIVE LOADS (2)
PASSIVE LOSSLESS SNUBBER (2)
POWER 300 W (2)
POWER CONVERSION (2)
POWER ELECTRONICS (2)
POWER FACTOR CORRECTORS (2)
POWER GRIDS (2)
PULSEWIDTH MODULATION (2)
PWM INVERTORS (2)
RESISTORS (2)
SMALL-SIGNAL CHARACTERISTICS (2)
SNUBBER CAPACITOR (2)
SOFT-SWITCHING (2)
STATE-ENERGY PLANE (2)
STEADY-STATE (2)
STRESS (2)
SUPPLY VOLTAGE DIP (2)
SWITCHING SURFACE (2)
TESTING (2)
TIME-DOMAIN ANALYSIS (2)
TOPOLOGY (2)
TOTAL HARMONIC DISTORTION (2)
TRANSFORMER LEAKAGE INDUCTANCE (2)
VOLTAGE REGULATORS (2)
ZERO-VOLTAGE SWITCHING (2)
ZVS (2)
120 W (1)
220 V (1)
36 W (1)
50 HZ (1)
AC-DC POWER CONVERTORS (1)
ACTIVE CANCELLATION (1)
ACTIVE MODULATION TECHNIQUE (1)
ACTIVE NONLINEAR MODULATION TECHNIQUE (1)
ACTIVE SNUBBER (1)
ADAPTABLE SOFT SWITCHING (1)
ADAPTABLE SOFT-SWITCHING (1)
ADAPTIVE SOFT- SWITCHING ENERGY (1)
ALGORITHM DESIGN AND ANALYSIS (1)
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INFONA - science communication portal

Search results for: H.S.H. Chung

A Novel Set-Based Particle Swarm Optimization Method for Discrete Optimization Problems

Active cancellation of capacitor ESR and ESL effects for improving converter transient and steady-state response

Passive lossless snubber with minimum voltage and current stress for boost PFC

Dynamic control of a light-emitting diode system based on the general photo-electro-thermal theory

Constant-frequency hysteresis current control of grid-connected VSI without bandwidth control

A ZCS full-bridge converter without voltage over-stress on the switches

A passive lossless snubber cell with minimum stress and wide soft-switching range

Modeling and Analysis of a Current-Fed ZCS Full-Bridge DC/DC Converter with Adaptive Soft-Switching Energy

A ZCS Current-Fed Full-Bridge PWM Converter With Self-Adaptable Soft-Switching Snubber Energy

Current source ballast for high power lighting emitting diodes without electrolytic capacitor

Effective standby power reduction using non-dissipative single-sensor method

A ZCS full-bridge PWM converter with self-adaptable soft-switching snubber energy

Optimization of power electronic circuits using ant colony system

Fixed-frequency boundary control of buck converters with second-order switching surface

Application of hybrid PWM and passive resonant snubber for grid-connected CSI

Design and Implementation of a Fast Dynamic Control Scheme for Capacitor-Supported Dynamic Voltage Restorers

Fast Dynamic Control Scheme for Capacitor-Supported Dynamic Voltage Restorers: Design Issues, Implementation and Analysis

Strategy for Current Harmonic Reduction of PFC with Boundary Control Using Second-order Switching Surface

A ZCS Isolated Full-Bridge Boost Converter with Multiple Inputs

Iterative Behavioral Modeling of Charge-Pump Based Electronic Ballast-Fluorescent lamp System

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