• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.301-310
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• 2007

Bidirectional DC-DC converters allow transfer of power between two dc sources, in either direction. Due to their ability to reverse the direction of flow of power, Dey are being increasingly used in many applications such as battery charge/dischargers, do uninterruptible power supplies, electrical vehicle motor drives, aerospace power systems, telecom power supplies, etc. This Paper Proposes a new bidirectional Sepic/Zeta converter. It has low switching loss and low conduction loss due to auxiliary communicated circuit and synchronous rectifier operation, respectively Because of positive and buck/boost-like DC voltage transfer function(M=D/1-D), the proposed converter is very desirable for use in distributed power system. The proposed converter also has both transformer-less version and transformer one.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.993-997
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• 1998

This paper presents a two-switch boost chopper with a sinewave current shaping and power factor correction scheme, which is applied for driving electronic ballast using high frequency resonant inverter. A working principle of the proposed one-converter type electronic ballast with power factor correction and active filtering schemes is described on the bases of the equivalent circuit of each operation mode, together with operation analysis. The steady-state performance evaluations of this electronic ballast are illustrated and discussed in experiment.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.551-554
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• 2002

This paper describes a new interactive inverter between a photovoltaic(PV) array and single-phase utility that avoid the bulky input (60Hz) transformer on the AC side. The interface employs a pwm boost converter on the DC side followed by a pwm current-forced single-phase rectifier for injecting the power from the PV array into the mains. The current waveform at the AC side remains sinusoidal and exactly in phase at all time. The circuit also has the advantage of requiring fewer switching device than high-frequency link system. This paper describes modeling of PV array and new system topology. Simulation results on the performance of the connection are also presented.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.447-449
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• 2006

본 논문에서는 변압기를 이용한 새로운 PDP용 전력회수회로를 제안한다. 2권선형 변압기를 이용하여 패널에 저장된 에너지를 전원으로 회생시켜 방전 이외의 용량성 부하로 기인하는 전력손실을 최소화 한다. 제안된 회로는 주스위치의 영전압 스위칭과 보조 스위치의 영전류 스위칭이 가능하고 변압기를 이용하기 때문에 권선비에 의한 자유로운 공진에너지 조절이 가능한 장점을 갖는다. 변압기 이용으로 인해 영전압 및 고속구동을 위한 천이시간 증가시 전류주입모드와 전압인가모드를 동시에 사용할 수 있는 장점을 갖는다. 제안된 회로의 성능과 하이브리드 모드 구동시에 나타나는 장점을 42인치 PDP적용실험을 통해 검증해본다.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.781-784
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• 2003

In this paper, high density on-board dc/dc converter using multi-layer PCB is proposed. Recently, the communication system wants power supply of open-frame, high density and low profile. So experimental converter was consisted of 3.3V/30A Quarter Brick size DC/DC Converter. To power height limit, coil of transformer, choke and circuits were consisted of multi layer PCB. Besides to improve of efficiency, made secondary synchronous rectifier Mosfet driving circuit. So total efficiency could be improved.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.275-278
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• 2003

Conventional vector control inverter is usually used for blower of air-accord equipment. In this paper, it is proposed that inverter is controlled by instantaneous following PWM controller. This controller compensate and follow for output voltage of inverter within one switching cycle as an error that compared output voltage of rectifier included much ripples with reference voltage of sine wave. It has not speedy response like vector controller, but the circuit is very simple as using analog integer. And it has advantages that develop input power factor, built small-capacity and low-cost because huge capacitor of voltage type inverter removed.

• Journal of Power Electronics
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• v.16 no.2
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• pp.399-413
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• 2016

This paper presents a topology for a modular power electronic transformer (PET) and a control scheme. The proposed PET consists of a cascaded H-Bridge rectifier on the primary side, a high-frequency DC/DC conversion cell in the center, and a cascaded H-Bridge inverter on the secondary side. It is practical to use PETs in power systems to reduce the cost, weight and size. A detailed analysis of the structure is carried out by using equivalent circuit. An algorithm to control the voltages of each capacitor and to maintain the power flow in the PET is established. The merits are analyzed and verified in theory, including the bi-directional power flow, variable voltage/frequency and high power factor on the primary side. The experimental results validated the propose structure and algorithm.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.142-143
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• 2010

An active-clamped current-fed half-bridge converter for the high step-up application is proposed in this paper. The proposed converter is composed of active clamping snubber circuits and a voltage doubler rectifier. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, features, and validity of the proposed circuit, the experimental result for a 200W, 24V input and 400V output prototype are presented.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.242-243
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• 2010

This paper investigates a power supply of medium voltage with enhanced ignition characteristics for plasma torch. Series resonant half-bridge topology is presented to be a suitable ignition circuitry. The ignition circuitry is integrated into the main power conversion system of a multi-phase staggered three-level dc-dc converter with a diode front-end rectifier. The plasma torch rated for 3MW, 2kA and having the physical size of 1m long is selected to be a high enthalpy source in waste disposal system. The steady-state and transient operations of plasma torch are simulated. The parameters of Cassie-Mary arc model are calculated based on 3D magneto-hydrodynamic simulations. Circuit simulation waveform shows that the ripple of arc current can be maintained within ${\pm}10%$ of its rated value under the existence of load disturbance. This power conversion configuration provides high enough ignition voltage around 5KA during ignition phase and high arc stability under the existence of arc disturbance noise resulting in a high-performance plasma torch system.

• Journal of Power Electronics
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• v.12 no.2
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• pp.258-267
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• 2012

An interleaved single-stage AC/DC converter with a boost converter and an asymmetrical half-bridge topology is presented to achieve power factor correction, zero voltage switching (ZVS) and load voltage regulation. Asymmetric pulse-width modulation (PWM) is adopted to achieve ZVS turn-on for all of the switches and to increase circuit efficiency. Two ZVS half-bridge converters with interleaved PWM are connected in parallel to reduce the ripple current at input and output sides, to control the output voltage at a desired value and to achieve load current sharing. A center-tapped rectifier is adopted at the secondary side of the transformers to achieve full-wave rectification. The boost converter is operated in discontinuous conduction mode (DCM) to automatically draw a sinusoidal line current from an AC source with a high power factor and a low current distortion. Finally, a 240W converter with the proposed topology has been implemented to verify the performance and feasibility of the proposed converter.