• Journal of IKEEE
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• v.23 no.4
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• pp.1280-1287
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• 2019

Grid-connected bidirectional PCS(Power Conditioning System) technology is a technology for implementing distributed renewable energy smart grid. And it is always charged by using power collected from solar modules and commercial grid power among vast smart grid systems, and stored when needed.It is a hybrid energy storage device that allows power to be released into the low voltage system. To this end, a PV input power converter with MPPT function, a bidirectional power converter for battery charging and discharging, and a DC Link input are output to a 3 phase 380V AC system, and if nessary, the bidirectional DC/DC converter We designed and developed a PCS with three power converter structures composed of inverters that perform battery charging. Currently, this system is applied to the site of Jeju, which is vulnerable to power outages and fire accidents.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.366-373
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• 2005

This paper presents two new circuit topologies of the dc busline side active resonant snubber assisted voltage source high frequency link soft switching PWM full-bridge dc-dc power converters acceptable for either utility ac 200V-rms or ac 400V-rms input grid. These high frequency switching dc-dc converters proposed in this paper are composed of a typical voltage source-fed full-bridge PWM inverter, high frequency transformer with center tap, high frequency diode rectifier with inductor input filter and dc busline side series switches with the aid of a dc busline parallel capacitive lossless snubber. All the active switches in the full-bridge arms as well as dc busline snubber can achieve ZCS turn-on and ZVS turn-off transition commutation with the aid of a transformer leakage inductive component and consequently the total switching power losses can be effectively reduced. So that, a high switching frequency operation of IGBTs in the voltage source full bridge inverter can be actually designed more than about 20 kHz. It is confirmed that the more the switching frequency of full-bridge soft switching inverter increases, the more soft switching PWM dc-dc converter with a high frequency transformer link has remarkable advantages for its power conversion efficiency and power density implementations as compared with the conventional hard switching PWM inverter type dc-dc power converter. The effectiveness of these new dc-dc power converter topologies can be proved to be more suitable for low voltage and large current dc-dc power supply as arc welding equipment from a practical point of view.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.219-225
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• 2014

This paper describes an IC for Power Factor Correction. It can use electrical appliances which convert power from AC to DC. The power factor can be influenced not only phase difference of voltage and current but also sudden change of current waveform. This circuit enables current wave supplied to load by close to sinusoidal and minimum phase difference of voltage and current waveform. A self oscillated 10[kHz]~100[kHz] pulse signal converted to PWM waveform and it chops rectified full wave AC power which flows to load device. The multiplier and zero current detector circuit, UVLO, OVP, BGR circuits were designed. This IC has been designed and whole chip simulation use 0.5[um] double poly, double metal 20[V] CMOS process.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1437-1443
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• 2004

In this paper, AC electric vehicle propulsion system(Converter/Inverter) using high power semiconductor, IPM(Intelligent Power module) is proposed. 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the VVVF inverter control is used a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region. The proposed propulsion system is verified by experimental results with a 1,350kW converter and 1.100kVA inverter with four 210kW traction motors.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.67-75
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• 2011

The development of electric vehicle power electronics system control, composed of DC-AC inverters and DC-DC converters, attract much research interest in the modern industry. A DC-AC inverter supplies the high-power motor torques of the propulsion system and utility loads of electric vehicles, whereas a DC-DC converter supplies the conventional low-power and low-voltage loads. However, the need for high-power bidirectional DC-DC converters in future electric vehicles has led to the development of many new topologies of DC-DC converters. The nonlinear control of power converters is an active research area in the field of power electronics. This paper focuses on the use of the fuzzy sliding mode strategy as a control strategy for buck-boost DC-DC converter power supplies in electric vehicles. The proposed fuzzy controller specifies changes in control signals based on the surface and knowledge on surface changes to satisfy the sliding mode stability and attraction conditions. The performance of the proposed fuzzy sliding controller is compared to that of the classical sliding mode controller. The satisfactory simulation results show the efficiency of the proposed control law, which reduces the chattering phenomenon. Moreover, the obtained results prove the robustness of the proposed control law against variations in load resistance and input voltage in the studied converter.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.486-487
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• 2011

In this paper, a configurable DC distributiong system is being proposed considering national power systems conditions and a comparative analysis of the transient response of the contingencies is performed with the conventional AC systems. DC systems are evaluated as a promising next-generation distribution system that provides reliable operation through high efficiency of energy use and converter control. This paper discusses about the required elements for the national DC distribution system and has analysed the fault characteristics of the AC and DC distribution systems using PSCAD/EMTDC. According to the simulation results, the DC system has improved response, due to the DC/DC converter's charging/discharging characteristics, in terms of voltage and power system characteristics when compared to AC systems.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.379-381
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• 1995

Many new electronic products are required to have a near unity power factor and a distortion free input current waveform. In this paper, a high performance single phase PWM AC/DC converter with input power factor correction is proposed. This proposed control strategy has many advantages which include one semiconduction switch, simplified control circuit, high performance features and continuous input current. The experimental results are included to verify the validity of this approach.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.524-525
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• 2012

본 논문은 단상 양방향 PWM 컨버터와 공진형 컨버터를 이용한 AC-DC 전력변환 장치를 제안한다. 공진형 컨버터는 변압기의 누설인덕턴스와 정류부의 커패시터를 이용하여 ZCS, ZVS를 얻는다. 제안된 컨버터 설계를 설명하며 시뮬레이션 결과와 실험 결과를 제시한다.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1325-1335
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• 2018

This paper presents a discontinuous pulse width modulation (DPWM) method to reduce switching losses in an indirect matrix converter (IMC) drive. The IMC has a number of power semiconductor switches. In other words, it consists of a rectifier stage and an inverter stage for AC/AC power conversion, which are composed of 12 and 6 switching devices, respectively. Therefore, the switching devices of the IMC suffer from high switching losses in the IMC drives. Various topologies to reduce switching losses have been studied by eliminating a number of switches from the rectifier stage. In this study, in contrast to prior research, a DPWM method is presented to reduce the switching losses of the inverter stage. The effectiveness of the proposed method to reduce switching losses in IMC drives is verified by simulations and experimental results.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.126-128
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• 1993

Rectifiers of power conversion system are widely used condenser at input to be cheap and to be simple construction. But this method is produced harmonics of pulse at peak value of input AC voltage. The main circuit which make input current of a sinusoidal wave and improve power-factor is almost taken step-up converter. This paper is able to obtain high power-factor and efficiency because the input current is made sinusoidal wave in single phase alternating current(AC) source. Also the proposed converter is able to minimize switching loss by ZVCS(zero voltage switching and zero current switching).