• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.1030-1035
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• 1998

This paper describes a new dc-ac inverter system, which for achieving sinusoidal ac waveform make use of parallel loaded frequency resonant inverter consisting of full bridge. Each one of the pair of switches in the inverter is driven to synchronous output frequency and the other is driven to PWM signal with resonant frequency proportional to magnitude of sine wave. Since current through switches is always zero at its turn-on in proposed inverter, low stress and low switching loss is achieved. The theoretical analysis is proved through the experimental test.

• 전력전자학회논문지
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• 제19권2호
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• pp.157-163
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• 2014

This paper proposes a two-stage step-down buck and a tapped-inductor boost cascaded converter for high efficiency photovoltaic micro-inverter applications. The proposed inverter is a new structure to inject a rectified sinusoidal current into a low-frequency switching inverter for single-phase grid with unity power factor. To build a rectified-waveform of the output current. the converter employs both of a high efficiency step-up and a step-down converter in cascade. In step-down mode, tapped inductor(TI) boost converter stops and the buck converter operates alone. In boost mode, the TI converter operates with the halt of buck operation. The converter provides a rectified current to low frequency inverter, then the inverter converts the current into a unity power-factor sinusoidal waveform. By applying a TI, the converter can decrease the turn-on ratios of the main switch in TI boost converter even with an extreme step-up operation. The performance validation of the proposed design is confirmed by an experimental results of a 120W hardware prototype.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.746-748
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• 1993

To overcome the problem of the diode reverse recovery in high switching frequency inverter, a new gate drive scheme is proposed for IGBT in this paper. Using this circuit, the reverse recovery current can be controlled and faster switching time can be achieved for hard switching inverter. The over-current protection method, which is suitable for the proposed gate driver, is also presented. The operation of the proposed circuit is investigated and its usefulness is verified through the experimental results.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권11호
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• pp.628-634
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• 2002

A capacitor-charging power supply using high frequency inverter technology is strongly recommended for the charging section of the pulsed power supplies. A high frequency inverter swiching makes the overall system size small. The command-charging feature can guarantee the higher reliability of switching function. The protection circuit can be easily included in the system and the good regulation of charging voltage can be acieved by the feedback system. Several modules can be stacked to supply required output power and a failed module can be easily replaced. A 50-kV, 35-kW capacitor charging power supply is developed. In this paper the detailed design and test results of a prototype unit are presented.

• 조명전기설비학회논문지
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• 제22권6호
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• pp.26-33
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• 2008

본 연구에서는 일반적으로 용접기의 전원장치로 사용되어지는 풀-브리지 회로에 1개의 스위치와 1개의 무손실스너버 부분 공진 커패시터로 구성된 간단한 액티브 보조 부분 공진 스너버를 추가한 새로운 풀-브리지 소프트 스위칭 PWM DC-DC 컨버터를 제안하였다. 제안한 풀-브리지 소프트 스위칭 DC-DC 컨버터 회로는 각 액티브 스위치에 인가된 전압이 DC 버스 라인 전압의 1/2로 되기 때문에 AC 400(V)계 상용전원 라인에 적용할 경우에도 600(V)내압의 스위칭 소자(IGBT)가 적용 가능하며, 기존 회로의 DC버스 라인 스위치에 발생되는 도통 손실을 저감하여 고주파 변압기의 1차측의 전류가 2차측보다 작아지는 저 전압, 대전류 직류 출력을 얻어 수 있었다. 그리고 모든 영역에서 ZCS/ZVS 동작함으로써 저전압, 대전류 직류 출력의 스위칭 전원 장치에 있어 고주파, 고효율, 고출력을 실현할 수 있다. 이러한 모든 사항은 시뮬레이션과 실험 결과로부터 도출하였으며, 제안한 회로의 단점을 보완할 경우에는 차세대형 TIG MIG MAG 아크 용접기용 전원으로 용이할 것으로 판단된다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.173-178
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• 2000

The time sharing type high frequency inverter using serial-parallel resonant to give VVVF function in the inverter used as power source of induction heating at high frequency is presented in this paper. This proposed inverter can reduce distribution of the switching current because of using the current of serial resonant circuit to the input current of the parallel one. The analysis of the proposed circuit is generally described by using the normalized parameters. Also, according to the calculated characteristics value, a method of the circuit design and operating characteristics of the inverter is proposed. In addition, this paper proves the validity of theoretical analysis through Simulation. This proposed inverter show that it can be practically used in future as power source system for induction heating application, DC-DC converter etc.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.419-422
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• 2008

This paper presents a novel prototype of ZCS-PFM high frequency series resonant Inverter using IGBT power module for electromagnetic induction eddy current-heated roller in copy and printing machines. The operating principle and unique features of this voltage source half bridge inverter with two additional soft commutation inductor snubber are presented Including the transformer modeling of induction heated rolling drum. This soft switching inverter can achieve stable zero current soft commutation under a discontinuous and continuous resonant load current for a widely specified power regulation processing. The experimental results and computer-aided analysis of this inverter are discussed from a practical point of view.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.707-710
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• 2005

This paper presents a 3kW grid-connection photovoltaic power generation system and its topology. Photovoltaic system must provide the sinusoidal output voltage wave for unity power factor High frequency switching converters are becoming more popular because of several benefits which are essential in power conversion system. This paper introduces a high speed digital controller using TMS320F2812 DSP chip which can be used for high frequency switching converters. The experimental results of the proposed PWM Inverter demonstrates its high performance with unity input power factor having very low distorsion in input current waveforms and good dynamic characteristics at full load.

• 전력전자학회논문지
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• 제13권1호
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• pp.9-14
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• 2008

멀티레벨 인버터 시스템에 낮은 스위칭 주파수가 사용되면, 이들 멀티레벨 인버터 시스템은 큰 값의 저 주파수 고조파 성분을 발생한다. 일반적으로 이러한 문제를 해결하기 위해 LC필터가 인버터 시스템의 출력단에 사용되었다. 그러나 LC필터를 사용한 경우 제동저항의 사용에 의한 전압강하가 발생하고, 제동저항의 전력손실로 인해 시스템의 효율이 감소하는 문제를 야기하게 된다. 본 논문에서는 낮은 스위칭 주파수를 갖는 3상 NPC 3레벨 인버터를 위한 출력 필터 설계방법을 제안하였다. 그리고 제안된 필터 시스템의 효율을 분석하였고, 제안된 시스템의 효과는 시뮬레이션과 실험결과를 통하여 입증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.403-405
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• 2007

This paper presents the over-modulation strategy and indirect vector control drive of NPC type PWM inverter. NPC inverter has three level phase voltage output.It can perform in high voltage through assembling switching components. It has less harmonics and surge voltage stress at motor terminals than the 2 level inverter in same switching frequency through 3 level voltage. The conventional railway vehicle has used the vector control to MI=0.907 and the slip-frequency control from MI=0.907 to six-step mode. The slip-frequency control has bad motive power and slow torque control response. But vector control has good motive power and can instant torque control. In this paper, output voltage is controlled linearly from linear region to six-step mode by using over-modulation strategy. And NPC inverter is used.