• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.3
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• pp.211-219
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• 2009

In this paper, a detailed analysis of zero current or zero voltage switching boost converter using a single switch is described. The proposed topology is capable of decreasing switching loss of IGBT device using soft switching technique. As a results, it can be reduced size and weight of passive elements. Based on the mode analysis, practical design considerations are presented. We confirm the converter topology, principle of operation and simulation results obtained from the PSIM software. The performance of the proposed converter is verified by with 1kW(400V, 2.5A) prototype circuit operated at 30kHz.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.4
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• pp.383-390
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• 2014

This paper deals with novel soft-switching method for a bidirectional DC-DC converter in battery charging and discharging system. The proposed soft-switching method provides ZVS and ZCS at turn-on, and ZVS at turn-off of the switch in both charging and discharging operation modes. The soft switching condition can be obtained in wide load range, and provide low switching loss as well as low voltage spike at turn-off of the switch. Proposed method is analyzed in charging and discharging mode. Simulation and experimental results validate the usefulness of the proposed soft-switching method.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1563-1576
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• 2017

This paper presents a novel switching pattern current control (SP-CC) scheme, which is applied in three-phase voltage-source converters (VSCs). This scheme can select the optimal output switching pattern (SP) by referring the basic principle of space vector modulation (SVM). Moreover, SP-CC is a method without a carrier wave. Thus, the implementation process is concise and easy. When compared with the conventional hysteresis current control (C-HCC) and the space vector-based hysteresis current control (SV-HCC), the SP-CC has the performances of faster dynamic response of C-HCC and less switching number (SN) of SV-HCC. In addition, it has less harmonic contents in the three-phase current, along with a lower switching loss and a higher efficiency. Moreover, the hysteresis bandwidth and Clarke conversion are not required in the SP-CC. The effectiveness of the presented SP-CC is verified by simulation and experimental test results. In addition, the advantages of the SP-CC, when compared with the C-HCC and SV-HCC, are verified as well.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.3
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• pp.365-371
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• 2019

Recently, the demonstration and research on the power transmission using high voltage DC such as HVDC(High Voltage DC), Smart Grid, DC transmission and distribution have been actively conducted. In order to control the power converter in high-voltage DC power transmission system, SMPS(Switching Modulation Power Supply) for power converter control using high-voltage DC input is essential. However, the demand for high-pressure SMPS is still low, so the development is not enough. In the low-output SMPS using the high-voltage input, it is difficult to achieve high efficiency due to the switching transient loss especially at light load. In this paper, we propose a new switching scheme for high power SMPS control for low output power. The proposed method can provide better efficiency increase effect in the light load region compared to the existing PWM method. To verify the feasibility of the proposed method, a 40 W SMPS for HVDC MMC(Modulation Multi-level Converter) was designed and verified by simulation.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.668-672
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• 2001

The utility interactive sinewave modulated inverter for the solar photovoltaic (PV) power conversion and conditioning with a new high frequency pulse modulated link is presented for domestic residential applications. As compared with the conventional full-bridge hard switching PWM inverter with a high frequency AC link, the simplest single-ended quasi-resonant soft switching sinewave modulated inverter with a duty cycle pulse control is implemented, resulting in size and weight reduction and low-cost. This paper presents a prototype circuit of the single-ended zero voltage soft switching sinewave inverter for solar power conditioner and its operating principle. In addition, this paper proposes a control system to deliver high quality output current. Major design of each component and the power loss analysis under actual power processing is also discussed from an experimental point of view. A newly developed interactive sinewave power processor which has $92.5\%$ efficiencty at 4kW output is demonstrated. It is designed 540mm-300mm-125mm in size, and 20kg in weight.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.542-545
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• 2002

This paper deals with the optimization inverter design and minimization Conduced EMI noise by customizing IPM(Intelligent Power Module). Generally, In case of IPM, we realized that the trade-off relation between switching loss and spike voltage. Higher gate resistor causes tile lower spike voltage and the higher turn-off switching loss. But we know that the life cycle of inverter and the susceptibility of noise, so we optimized the gate resistor. Proposed method is that optimized the gate resistor suitable for the inverter and motor. The simulation and experimental results show that the spike voltage and Conduced EMI noise can be reduced without the additional circuit.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.140-142
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• 2005

SMPS의 손실에는 switching loss, conduction loss, core loss가 있다. 최근 SMPS에서는 switching loss를 줄여 효율을 높이고자 반도체 스위치 2개를 사용하는 공진형 구조가 증가하고 있다하지만 공진형 구조는 반도체 스위치에서 소비되는 conduction loss로 의해 기존의 컨버터에 비해 무부하시 전력 소모가 크다. 그러나 최근 시장은 무부하시 소비되는 대기전력의 규제가 이슈가 되고 있다. 본 논문에서는 active clamped flyback converter에서 무부하시 반도체 스위치의 conduction loss의 감소를 위해 Clamp 회로의 보조 스위치는 동작시키지 않고, flyback converter로만 동작하도록 설계하여 무부하시에는 기존의 flyback converter의 동작과 같이 도통 손실이 급속히 줄도록 하였다. 또한 스위칭 손실을 줄이기 위해 주 스위치의 동작 주파수를 감소시켜 SMPS의 무부하시의 소모를 감소시켰다. 70W급 SMPS의 제작과 실험을 통해 위의 방법을 증명하고자 한다.

• Journal of Power Electronics
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• v.16 no.1
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• pp.388-397
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• 2016

An error-compensated pulse width modulator (ECPWM) is proposed to improve the baseband harmonic performance and the switching loss of voltage source inverters (VSIs). Selecting between harmonic distortion and switching loss is a design tradeoff in the conventional space vector pulse width modulation. In this work, an accumulated difference in produced and desired phase voltages is considered to adjust the reference signal. This mechanism can compensate for the voltage error in the previous carrier period. With error compensation every half-carrier period, the proposed ECPWM allows one-half reduction in carrier frequency without scarifying baseband harmonic distortion. The proposed modulator is applied to a three-phase VSI with R-L load and a motor-speed-control system for experiments. The measured efficiency and operating temperature of switches confirm the effectiveness of the proposed scheme.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.126-128
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• 2007

This paper presents a new soft switching dc-to-dc converter that employs IM transformer. Detailed analysis and design considerations of the proposed circuits are presented. By applying the proposed magnetic integration procedure, new integrated magnetic circuits featuring low loss, simple structure are then developed to overcome the limitations of prior art. Consequently, the power loss and the size of the integrated magnetic device are greatly reduced. The operation and performance of the proposed converter are demonstrated with an experimental converter that delivers a 5V/5A output from a 48V input at the maximum efficiency of 90 %.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.3
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• pp.19-25
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• 2008

In this paper, author proposes a novel step-up AC-DC chopper operated with power factor correction(PFC) and with high efficiency. The proposed chopper behaves with discontinuous current control(DCC) of input current. The input current waveform in the proposed chopper is got to be a discontinuous sinusoid form in proportion to magnitude of ac input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity and the control method is simple. In the general DCC chopper, the switching devices are turned-on with the zero current switching, but turn-off of the switching devices is switched at current maximum value. To achieve a soft switching of the switching rum-off, the proposed chopper is used a new partial resonant circuit. The result is that the switching loss is very low and the efficiency of chopper is high.