• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1578-1588
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• 2015

In this paper, an improved KY converter is presented, which is constructed mainly by one charge pump capacitor and one central-tapped coupling inductor. Besides, a passive clamping snubber is added to this converter to improve the efficiency above half load. As compared to the KY converter, the voltage conversion ratio of the proposed converter is upgraded significantly. In this paper, the basic operating principles and mathematical deductions of the proposed converter are described, along with some experimental results provided to demonstrate the feasibility and effectiveness of the proposed converter.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.3
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• pp.8-18
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• 2010

According to the needs of change to hybrid, fuel cell and electric vehicle, and to the increasing demand for safety and eco-friendliness, the necessity of Electro-Mechanical Brake(EMB) is being increased. But, one of the most important problems for realizing EMB to the practical use is that the required motor power for braking is too high. So the high braking efficient EMB is required. In recent years, the Electronic Wedge Brake(EWB) is noticeable for the high braking efficiency. In this research, we examine the improvable matter of the recent published EWB, and we propose the improved mechanism and the cost effective control method using this mechanism. And we test these feasibility by experiment and discuss these meaning and effect.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.9
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• pp.598-606
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• 2000

This paper proposes a new snubber circuit for 4-level inverter and converter. The snubber circuit makes use of Undeland snubber and McMurray efficient snubber as basic snubber unit and can be regarded as a generalized combined Undeland and McMurray efficient snubber. The proposed snubber keeps such good features as fewer number of components improved efficiency due to low snubber loss capability of clamping overvoltage across main switching devices and no unbalance problem of blocking voltage. Furthermore the proposed concept of constructing a snubber circuit for 4-level inverter and converter can apply to any level of converterand inverter.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.94-101
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• 2013

Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. The objective of this study is to implement the best plastic injection molding process for LED TV speaker frame. Moldflow analysis and simulation of plastic injection molding process were carried out in order to predict optimal modeling operation conditions and then injection molded part was produced various type of resin temperature, filling time and injection pressure variation. the result was that the best injection molding condition is set as 60bar pressure, 2sec filling time and $310^{\circ}C$ degree. The study result would be useful to variety of plastic injection molding process.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.541-546
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• 1998

This paper proposes a new snubber circuit for multilevel inverter and converter. The snubber circuit makes use of Undeland snubber as basic snubber unit and can be regraded as a generalized Undeland snubber. The proposed snubber keeps such good features as fewer number of components, improved efficiency due to low loss snubber, capability of clamping overvoltage across main switching devices, and no unbalance problem of blocking voltage. Furthermore, the proposed concept of constructing a snubber circuit for multilevel inverter and converter can apply to any kind of basic snubber unit such as Holtz nondissipative snubber, McMurray efficient snubber, Lauritzen lossless snubber, etc which have been utilized for two-level inveter.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.2
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• pp.257-261
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• 2017

Drilling file is medical mini-drill which is made of Ni-Ti material and has tapered shape. It's for removing teeth nervine which helps the endodontic treatment. All files, saled at domestic market, are imported from U.S. and Europe. Also they have low manufacturing efficiency and high price because it is made by universal 5 axis CNC grinding machine. To solve these problem, 3 axis CNC table, controllable tilting angle spindle and helix angle moving table are devised. To confirm divised CNC grinding machine's manufacturing accuracy, conveying amount and finish product size measurement expreiment has been practiced. Also to automate all manufacturing processes, automatic mechanism is designed.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1928-1930
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• 1998

This paper proposes a new snubber circuit for multilevel inverter and converter. The snubber circuit makes use of Undeland snubber as basic snubber unit and can be regarded as a generalized Undeland snubber. The proposed snubber keeps such good features as fewer number of components, improved efficiency due to low loss snubber, capability of clamping overvoltage across main switching devices, and no unbalance problem of blocking voltage. Furthermore, the proposed concept of constructing a snubber circuit for multilevel inverter and converter can apply to any kind of basic snubber unit such as Holtz nondissipative snubber, McMurray efficient snubber, Lauritzen lossless snubber, etc which have been utilized for two-level inverter.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2169-2171
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• 1998

In order to improved the three phase GTO CSI of high efficiency IM drive with low loss commutation and snubber energy, we studied the energy recovery circuit to recover stored energy in clamping capacitor, dc link inductor and snubber capacitor, used an induction motor as the load of inverter. Specially, we investigated how dc input power is increased or decreased according to size of dc link inductor. The validity of this system is proved through experiment.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.28-30
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• 2020

본 논문에서는 위상천이 풀브릿지(PSFB) 컨버터에 적용할 수 있는 새로운 클램핑 회로를 제안한다. 제안하는 회로가 적용된 PSFB 컨버터는 정류기 다이오드의 전압 발진을 완전히 제거되면서도, 영전압 스위칭(ZVS)을 위한 전류를 보장하기 때문에 전도 손실과 스위칭 손실을 모두 개선하여 고효율을 달성할 수 있다. 뿐만 아니라, 출력 인덕터 부피와 듀티 손실 측면에서도 장점을 갖기 때문에 기존에 제안된 여러 클램핑 회로들에 비해서도 높은 효율과 높은 전력밀도를 갖는다. 제안된 회로의 타당성은 385V 입력, 270-420V 출력의 3.3kW 전기차 충전기 프로토타입으로 검증되었다.

• Journal of Power Electronics
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• v.4 no.1
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• pp.46-55
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• 2004

This paper presents a high-frequency ZVS-PWM boost chopper-fed DC-DC converter with a single active auxiliary edge resonant snubber in the load-side which can be designed for power conditioners such as solar photovoltaic generation, fuel cell generation, battery and super capacitor energy storages. Its principle operation in steady-state is described in addition to a prototype setup. The experimental results of ZVS-PWM boost chopper-fed DC-DC converter proposed here, are evaluated and verified with a practical design model in terms of its switching voltage and current waveforms, the switching v-i trajectory, the temperature performance of IGBT module, the actual power conversion efficiency and the EMI of radiated and conducted emissions. And then discussed and compared with the hard switching scheme from an experimental point of view. Finally, this paper proposes a practical method to suppress parasitic oscillation due to the active auxiliary resonant switch at ZCS turn off mode transition with the aid of an additional lossless clamping diode loop, and reduced the EMI conducted emission in this paper.