• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.5
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• pp.370-379
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• 1989

This paper describes a three-phase active power filter using voltage-source PWM converter, which can eliminate the harmonics and compensate the reactive power in the ac sides of 6-pulse rectifier. The active filter consists of three-phase PWM inverter and a capacitor, and the hysteresis control technique is used to make the compensating current close to the existing harmonic current and also to improve the response of the filter with simple control circuit. As a result the compensated ac line current becomes sinusoidal and the input power factor is improved roughly to unity.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.237-239
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• 2003

이 논문은 이중 출력과 단일 역률 적용에 대한 하나의 전력단 회로를 사용한 새로운 정류기를 나타낸다. 제안된 정류기는 부스트와 플라이백 컨버터가 결합된 하나의 전력단 회로를 갖는 구조를 가지고 있고, PFC(power factor correction) 와 일정 출력 전압 제어를 동시에 수행한다. 따라서, 제안된 정류기는 전형적인 AC/DC 정류기들(멀티 권선을 갖는 플라이 백 정류기, 투 스테이지 방식을 사용한 부스트와 플라이백 컨버터가 결합된 정류기 등등)보다 낮은 비용과 작은 사이즈의 장점을 갖는다. 제안된 정류기 회로의 동자 원리는 본 논문에서 상세하게 기술 되어진다. 그리고 시뮬레이션을 통하여 제안된 정류기의 타당성을 증명하였다.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.589-590
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• 2006

A novel Triple-Well P-type Triggered Silicon Controlled Rectifier (TWPTSCR) for on-chip ESD protection implemented with a triple-well CMOS technology is presented. Unlike conventional SCR devices, the proposed TWPTSCR offers a reduced triggering voltage level as well as the enhanced ESD performance of the SCR devices. From the experimental results, the TWPTSCR with a device width of 20um has the triggering voltage of 1.1V.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.549-551
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• 2005

Bidirectional DC/DC converters allows transfer of power between two dc sources, in either direction. Due to their ability to reverse the direction of flow of power, they are being increasingly used in many applications such as battery charger/dischargers, dc 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 swicthing 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 transformerless version and transformer one.

• Journal of Power Electronics
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• v.11 no.6
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• pp.931-937
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• 2011

This paper presents a method for the performance improvement of a shunt active power filter (SAPF) using the indirect current control (ICC) scheme. Compared to the conventional direct current control (DCC) scheme, the ICC gives better performance with a lower number of sensors. A simplified and efficient control algorithm using a low cost Intel 80C196KC microcontroller is implemented using only two current sensors for the source current and one voltage sensor for the DC-link voltage of the SAPF circuit. The objective is to eliminate harmonics and to compensate the reactive power produced by non-linear loads such as an uncontrolled rectifier feeding an inductive load. The APF is realized using a three phase voltage source inverter (VSI) with a dc bus capacitor. Experimental results are presented to prove the better performance of the ICC method over the DCC one.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.9
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• pp.468-474
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• 2003

This paper describes the development of an open frame type high power density switching converter. It is based on the active clamp forward converter with synchronous rectifier, and packaged by using the open frame and multi-layer printed circuit board (PCB) technology to achieve the higher power density. Furthermore, the windings of transformer and inductor are also realized by multi-layer PCB so that it also contributes to achieve higher power density. Through the experiment on the prototype converter of 50[W], it is confirmed that power density of 50[W/i$n_3$] and maximum efficiency of over 91[%] are obtained.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.246-247
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• 2017

단상 ac/dc, dc/ac 시스템의 경우, ac와 dc사이의 전력 불균형으로 인해 double line frequency ripple power가 발생한다. 이는 harmonic disturbance을 야기시킨다. 일반적으로 전력 리플을 줄이기 위하여 dc-link에 용량이 큰 전해 커패시터를 사용하는데, 용량이 큰 전해 커패시터는 높은 equivalent series resistance(ESR)을 가지며, 상대적으로 짧은 수명을 갖는 한계를 갖는다. 본 논문은 active power decoupling을 추가함으로써 전해 커패시터를 용량이 작은 필름 커패시터로 대체한 회로 구조를 제시한다. 그리고 dc-link 커패시터 선정방법, 설계한 제어기의 성능과 부하 변동에 따른 실험을 PSIM 시뮬레이션으로 확인하고 실험을 통해 검증한다.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1244-1246
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• 2003

Conventional Switched Mode Power Supplies(SMPS) with diode-capacitor rectifier have distorted input current waveform with high harmonic content. Typically, these SMPS have a power factor lower than 0.65. To improve with this problem. the power factor correction(PFC) circuit of power supplies has to be introduced. Specially, to reduce size and manufacture cost of power conversion device, the single-stage PFC converter is increased to demand as necessary of study. In this case single-stage PFC converter has been used DC-DC converter with boost converter. However in this paper, it is studied flyback converter of high power factor, high efficiency by feedforward control. Also, the validity of designed and manufactured high power factor flyback converter is confirmed by simulation and experimental results.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.249-253
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• 2011

This paper describes the fabrication and characteristics of vibration-driven electromagnetic energy harvester without spring to use at low frequency like a human body motion. The implemented energy harvester consists of NdFeB magnets, copper coil. The optimization of induced voltage was done by the various widths of coil, number of the turns, size of fixed and moving magnets and thicknesses of the cylinder. The fabricated energy harvester is capable of producing up to 15.0 $V_{pp}$ for basic model and 28.80 $V_{pp}$ for improved model at 5.0 Hz resonance frequency and 0.75 g acceleration level. The basic model and improved model are provided a maximum power of 6.375 mWand 25.831 mW at 1 KHz of load resistance in rectifier circuit.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.103-107
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• 2002

A contact-less power supply system (CPS) allows electrical energy to supply to mobile consumers without any electrical or mechanical contact. CPS works in the same principle as a transformer, with the track litz cable forming the primary circuit and the pickup as the secondary. The track power supply generates the high frequency alternating current in the track cable. The captured AC magnetic field generated by the track conductors produces electrical energy in the pickup coil and the pickup rectifier converts the high frequency AC power to DC while regulating the power to the load. This paper presents the theoretical analysis, simulation and experiment리 results of the series-parallel resonant converter working as contact-less power supply system.