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Author

Ching-Shan Leu

Bio: Ching-Shan Leu is an academic researcher from National Taiwan University of Science and Technology. The author has contributed to research in topics: Boost converter & Forward converter. The author has an hindex of 14, co-authored 41 publications receiving 1413 citations.

Papers
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Journal ArticleDOI
29 Jun 1992
TL;DR: In this paper, a class of zero voltage transition (ZVT) power converters is proposed in which both the transistor and the rectifier operate with zero voltage switching and are subjected to minimum voltage and current stresses.
Abstract: A class of zero voltage transition (ZVT) power converters is proposed in which both the transistor and the rectifier operate with zero voltage switching and are subjected to minimum voltage and current stresses. The boost ZVT-PWM converter is used as an example to illustrate the operation of these converters. A 300 kHz, 600 W ZVT-PWM boost, DC-DC converter, and a 100 kHz, 600 W power factor correction circuit using the ZVT-PWM technique and an insulated gate bipolar transistor (IGBT) device were breadboarded to show the operation of the proposed converters. It is shown that the circuit technology greatly improves the converter performance in terms of efficiency, switching noise, and circuit reliability. >

896 citations

Proceedings ArticleDOI
20 Jun 2004
TL;DR: In this paper, a family of inductor-less bus converters is proposed to overcome the limitations of current bus converter, magnetizing current is used to achieve zerovoltage-switching (ZVS) turn-on for all switches.
Abstract: This paper begins by reviewing current bus converters and exploring their limitations. Then a family of inductor-less bus converters is proposed to overcome the limitations. In the new bus converter, magnetizing current is used to achieve zero-voltage-switching (ZVS) turn-on for all switches. The resonant concept is used to achieve zero-current-switching (ZCS) without turn-off loss and body diode loss. Meanwhile, the self-driven method can be easily applied to save drive loss in the synchronous rectifiers. Based on these concepts, a full-bridge bus converter is built in the quarter-brick size to verify the analysis. The experimental results indicate that it can achieve 95% efficiency at 500 W, 12 V/45 A output. Compared with industry products, this topology can dramatically increase the power density.

73 citations

Proceedings ArticleDOI
13 Feb 1994
TL;DR: In this paper, the authors present design considerations for power converter modules used in a distributed power system, including front-end power converters and load-power converters, for a universal input voltage of 90-260 V AC, with a bus voltage of 48 V DC.
Abstract: This paper presents design considerations for power converter modules used in a distributed power system, including front-end power converter modules and load power converter modules. The system is designed for a universal input voltage of 90-260 V AC, with a bus voltage of 48 V DC. Several versions of the 600 W power factor corrected front-end power converter modules have been evaluated. One configuration includes a zero-voltage-transition PWM boost PFC circuit followed by a zero-voltage-switched active-clamp forward power converter. The second configuration uses an interleaved active-clamp flyback power converter for both the power factor correction and bus voltage regulation. 150 W and 300 W load power converter modules with 5 V output have been developed using the active clamp forward power converter topology and low-profile magnetics. >

64 citations

Journal ArticleDOI
TL;DR: A new full-wave rectifier is proposed that has several features, such as high voltage gain with smaller transformer turns ratio, recovery of the transformer secondary leakage energy, low voltage stress on the rectifier diodes, and nonpulsating input and output currents, that make it desirable for high-frequency high-efficiency high-voltage-gain applications, such the renewable energy source power system.
Abstract: A new full-wave rectifier is proposed in this paper. By integrating the proposed rectifier with a classic current-fed converter as an example, a dual-inductor boost converter with ripple cancellation is presented. It has several features, such as high voltage gain with smaller transformer turns ratio, recovery of the transformer secondary leakage energy, low voltage stress on the rectifier diodes, and nonpulsating input and output currents. These properties make it desirable for high-frequency high-efficiency high-voltage-gain applications, such as the renewable energy source power system. In addition to the circuit analysis and design, a 150-kHz 24-36-V-input 200-V/600-W-output converter prototype is implemented and tested to demonstrate its feasibility.

46 citations

Proceedings ArticleDOI
29 Jun 1992
TL;DR: In this article, a method for improving the performance of zero-voltage-switched multiresonant power converters (ZVS MRCs) is proposed, based on clamping the drain-to-source voltage of the power switch using a soft switching nonsipative active clamp network.
Abstract: A method for improving the performance of zero-voltage-switched multiresonant power converters (ZVS MRCs) is proposed, based on clamping the drain-to-source voltage of the power switch using a soft switching nondissipative active clamp network. Complete DC analysis and design guidelines for the clamp-mode forward ZVS-MRC are presented. Device is shown to perform significantly better than forward ZVS-MRCs without an active clamp. >

33 citations


Cited by
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01 Sep 2010

2,148 citations

Journal ArticleDOI
TL;DR: A review of the most interesting solutions for single phase and low power applications is carried out in this article, where the major advantages and disadvantages are highlighted and the field of application is found.
Abstract: New recommendations and future standards have increased the interest in power factor correction circuits. There are multiple solutions in which line current is sinusoidal. In addition, a great number of circuits have been proposed with nonsinusoidal line current. In this paper, a review of the most interesting solutions for single phase and low power applications is carried out. They are classified attending to the line current waveform, energy processing, number of switches, control loops, etc. The major advantages and disadvantages are highlighted and the field of application is found.

652 citations

Proceedings ArticleDOI
Dushan Boroyevich1, Igor Cvetkovic1, Dong Dong1, Rolando Burgos1, Fei Wang1, Fred C. Lee1 
20 May 2010
TL;DR: Several ideas for modeling, analysis, and system-level design of such systems, including power flow control, protection, stability, and subsystem interactions, are presented, especially in the presence of renewable energy sources.
Abstract: Although it has long been argued that electronic power converters can help improve system controllability, reliability, size, and efficiency, their penetration in power systems is still quite low. The often-cited barriers of higher cost and lower reliability of the power converters are quite high if power electronics is used as direct, one-to-one, replacement for the existing electromechanical equipment. However, if the whole power distribution system were designed as a system of controllable converters, the overall system cost and reliability could actually improve, as is currently the case at low power levels within computer and telecom equipment. Starting from the example of a computer power system, the paper contemplates possible future ac and dc electronic power distribution system architectures, especially in the presence of renewable energy sources. The proposed nanogrid-microgrid-…-grid structure achieves hierarchical dynamic decoupling of generation, distribution, and consumption by using bidirectional converters as energy control centers. This is illustrated by the description and simulation of static and dynamic operation of a dc nanogrid in a hypothetical future sustainable home. Several ideas for modeling, analysis, and system-level design of such systems, including power flow control, protection, stability, and subsystem interactions, are presented.

529 citations

Patent
01 Oct 2002
TL;DR: In this article, a Factorized Power Architecture (FPA) method and apparatus includes a front end power regulator (PRM) which provides one or more controlled DC bus voltages which are distributed through the system and converted to the desired load voltages using voltage transformation modules (VTMs) at the point of load.
Abstract: A Factorized Power Architecture (“FPA”) method and apparatus includes a front end power regulator (“PRM) which provides one or more controlled DC bus voltages which are distributed through the system and converted to the desired load voltages using one or more DC voltage transformation modules (“VTMs”) at the point of load. VTMs convert the DC bus voltage to the DC voltage required by the load using a fixed transformation ratio K=V out /V in and with a low output resistance. VTMs exhibit high power density, efficiency and, owing to their inherent simplicity and component utilization, reliability. VTMs may be paralleled and share power without dedicated protocol and control interfaces, supporting scalability and fault tolerance. Feedback may be provided from a feedback controller at the point of load to the front end or to upstream, on-board power regulator modules (“PRMs”) to achieve precise regulation.

389 citations

Journal ArticleDOI
20 Jun 1993
TL;DR: In this article, a new family of zero-current transition (ZCT) pulsewidth-modulated (PWM) converters is proposed for high power applications where the minority-carrier semiconductor devices (such as IGBTs, BJTs, and MCTs) are predominantly used as the power switches.
Abstract: A new family of zero-current-transition (ZCT) pulse-width-modulated (PWM) converters are proposed. The new family of converters implements zero-current turn-off for power transistor(s) without increasing voltage/current stresses and operates at a fixed frequency. The proposed converters are deemed most suitable for high-power applications where the minority-carrier semiconductor devices (such as IGBTs, BJTs, and MCTs) are predominantly used as the power switches. Theoretical analysis is verified on a 100-kHz, 1-kW ZCT-PWM boost converter using an IGBT. >

384 citations