• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2016년도 전력전자학술대회 논문집
• /
• pp.361-362
• /
• 2016

Presented in this paper is the design of a high voltage switch module made up of MOSFETs, pulse transformers and their gate driver circuits compactly fitted onto a single PCB module. The ease by which the switch modules can be configured (series stacking and/or parallel stacking) to meet future load variations allows for flexible operation of this design. In addition, the detailed implementation of the gate driver circuit for reliable and easier switch synchronization is also described in this paper. The stored energy in the capacitor bank of a 15kV, 4.5kJ/s peak power capacitor charger was discharged using the developed high voltage switch, and by experimental results, the operation of the proposed circuit was verified to be effectively used as a switch for pulse discharging.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.113-115
• /
• 2008

At the high speed operation, the high demagnetization voltage can reduce the negative torque, so the output power and efficiency can be improved. In this paper, a novel power converter for single phase SRM with high demagnetization voltage is proposed. A simple passive capacitor circuit is added in the front-end, which consists of three diodes and one capacitor. Based on this passive network, the two capacitors can be connected in series and parallel, so the phase winding of SRM obtains general do-link voltage in excitation mode and the double dc-link voltage in demagnetization mode. The operation modes of the proposed converter are analyzed in detail. Some computer simulation results is done to verify the performance of proposed converter.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 A
• /
• pp.495-497
• /
• 1996

This paper proposes LCC type high frequency resonant inverter to be used as a source of induction heating device or ultrasonic device and considers of operating characteristic for it. The inverter is operated safely over wide range load, because it has both panel loaded capacitor and series loaded capacitor. Then, switching frequency of the inverter is controlled by feedback voltage and current in order to have constant output power even when load is varied.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2017년도 추계학술대회
• /
• pp.151-152
• /
• 2017

본 논문에서는 고전압 입력을 가지는 LDC를 입력직렬-출력 병렬형 컨버터로 구성하여 모듈단위의 설계를 하였다. 이러한 형태의 각 모듈의 성분들이 이상적으로 동일하지 않은 단점을 가지고 있기 때문에 변압기의 Lr, 듀티비 D, 스위칭 주파수 fs에 따라서 입력전압의 편차 발생한다. 따라서 입력 전압의 편차를 저감시키기 위해서 입력 전압 밸런싱 제어를 적용하여 각 모듈의 전압을 동일하게 유지하여 출력 전류 제어를 진행 하여 제어방법의 타당성을 검증한다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.965_966
• /
• 2009

In this paper, a new soft-switching Two-switch Forward converter topology has been proposed. Compared with conventional two-switch forward converter, the proposed converter employs an auxiliary switch and a clamp capacitor to instead of two reset diodes, not only its duty cycle can exceed 0.5 to achieve wide range input voltage, but also soft switching can be achieved for all switches. Especially, voltage stress across main switches can be clamped at $1/2V_{in}$, voltage stress across auxiliary switch can be clamped at $V_{in}$. In addition, due to clamp capacitor series with the transformer, duty ratio can be extended with equation $V_o=\frac{V_{in}(1-D}D{N}$. Therefore, as a kind of better cost-effective approach, it is very attractive for high input, wide range and high efficiency application.

• 전력전자학회논문지
• /
• 제25권4호
• /
• pp.261-268
• /
• 2020

Transformer saturation in full bridge (FB) isolated DC-DC converters is caused by uneven switching speeds and voltage drops in semiconductor devices and mismatched gate signals. In order to prevent transformer saturation, most popular and widely used approach is to insert a capacitor in series with the transformer windings. This study conducts extensive analyses on transformer saturation and the effect of DC blocking capacitors when they are placed in the primary or secondary windings of a transformer. The effect of the DC blocking capacitors is verified in voltage-fed and current-fed FB converters.

• 전력전자학회논문지
• /
• 제18권2호
• /
• pp.145-152
• /
• 2013

Electrolytic capacitors used for smoothing DC link voltage is one of the major root causes of fault in power electronic system. The aging of aluminum electrolytic capacitors is expressed by the increase of their equivalent series resistance (ESR) and the reduction of their capacitance. Thus, the proposed technique in this paper is to measure capacitance, by comparing energy loss of DC link capacitors with stator resistor in electric machine. Condition of DC link capacitors can be estimated from the capacitance decrease rate between initial and aged capacitors. The results show that the proposed technique provides an easy, widely applicable and simple low cost solution for detecting dc link capacitor degradation.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.76-79
• /
• 2005

This paper describes the performance analysis and design of 1-phase self-excited induction generators. The minimum parallel capacitance of self-excited capacitor connected auxiliary winding and the series capacitance of regulating voltage capacitor connected main winding is proposed the suitable value using circuit equations of main and auxiliary winding. For the steady state analysis, the equivalent circuit of 1-phase induction generators is used as circuit modeling using the double-revolving field theory. The validity of designed generator system will be confirmed by experimental and computed results.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.168-171
• /
• 2005

The conception of the passive lossless snubber with the simpler is presented. Thus a necessity condition of the passive lossless soft switching converter with the simplest topology is directed. A novel passive regenerative snubber called soft snubber applied to a hard switching converter is proposed. The passive snubber consists of a snubber inductor, two snubber rectifiers, and a snubber capacitor. The losses are reduced by inserting a snubber inductor in the series path of the rectifier during it's turn off. It is so simple that can make energy reset or capacitor discharged directly without producing any current circulation. To show the superiority of this converter is verified through the experiment with a 640W, 100kHz prototype converter.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 학술대회 논문집 전문대학교육위원
• /
• pp.132-135
• /
• 2005

A design for the input filter and the output filter of a single-phase uninterruptible power supply (UPS) system is proposed. A filter design example is presented. And also, this dissertation describes a reduction of the DC voltage ripple of a single-phase UPS. The input power of proposed UPS fluctuates with twice frequency of the utility source, which causes DC voltage fluctuation. The reduction of the DC voltage fluctuation requires a large DC link capacitor. The proposed method uses a LC series resonant filter paralleled with a conventional smoothing capacitor. The effectiveness of the proposed method was confirmed by simulation results.