• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.1963-1965
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• 1998

In this paper, a new simplified configuration for a multi-level PWM inverter is proposed. The proposed inverter consists of an auxiliary circuit with one switching device, and 3 phase full-bridge inverter. The proposed inverter, in spite of reduction of the switching devices, offers characteristics similar to the NPC(Neutral - point - clamped)- PWM inverter. Also, since the reduction of the switching devices, the control strategy is simplified. And switching loss is reduced. In addition to, it is possible that reliable DC level voltage than former multi-level inverter. And load power application is same to conventional NPC-PWM inverter. The performance of the system is verified by simulation. In this paper, show the simulation result of the single phase full bridge inverter application.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.195-198
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• 2008

최근 태양광 발전시스템 등 낮은 전압을 발생하는 전원소스를 이용하여 높은 승압효과를 얻기 위한 멀티레벨 인버터에 대한 관심이 높아지고 있다. 본 논문은 FPGA 기반 멀티레벨 인버터용 스위칭 함수를 구현하고자 한다. FPGA는 프로그램 가능한 로직 디바이스로써 풀 디지털 스위칭함수를 구현하는 효율적이다. 본 논문에서는 FPGA 기반 스위칭 함수를 구현하기 위해서 마이크로프로세서로부터 출력되는 클럭과 동기신호로 독립적으로 구동이 되도록 하였다.

• 전력전자학회논문지
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• 제11권6호
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• pp.520-528
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• 2006

동일한 변압기를 사용하는 공통암 타입의 절연형 다중레벨 인버터에서 스위칭 주파수를 저감하기 위해 새로운 위상변위제어기법을 제안 하였다. 제안된 스위칭 방식은 인버터의 각 암이 기본주파수당 한번만을 스위칭을 하는 스텝 펄스파 방식을 사용하여 동일한 스위칭 주파수를 유지할 수 있다. 제안된 스위칭 방식의 타당성을 검증하기 위해 기존의 동일변압기를 이용한 멀티레벨 인버터의 스위칭 패턴과 제안된 위상변위 제어방식을 이용한 멀티레벨 인버터의 스위칭 패턴을 시뮬레이션하고 실험을 통해 비교 하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.425-429
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• 2004

A new multi-level type energy recovery sustaining driver for AC PDP(Plasma Display Panel) is proposed in this paper. The multi-level driver has been developed to reduce the voltage stress on switching elements. Comparing the proposed driver with the conventional multi-level driver, 4 switching elements, 4 diodes, and two auxiliary capacitors are eliminated in the viewpoint of circuit structure. Moreover, the voltage stress on switching elements is more reduced and the sustain period is extended. To verify the validity of the proposed energy recovery circuit, computer simulations using PSpice program are carried out.

• 전력전자학회논문지
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• 제7권2호
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• pp.111-120
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• 2002

멀티레벨 인버터 시스템은 낮은 고조파 성분과 높은 전력이 요구되는 분야에 매우 효율적인 시스템이다. 멀티레벨 인버터 시스템의 경우에 스위치 소자의 손실은 기존의 방법으로는 해석 할 수 없다. 그 이유는 각 스위치 소자의 손실이 2-레벨과는 다르게 서로 같지 않기 때문이다. 본 논문에서는 멀티레벨 인버터 시스템에 대한 전도 손실과 스위칭 손실의 간단하고 정확한 방법을 제안하였다. 제안된 방법의 타당함은 3-레벨과 4-레벨 다이오드 클램프드 인버터 시스템에 대해 증명하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.53-55
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• 2006

In this paper discusses winding methode of single phase AC-DC reversible power converter The reversible power converter driven by multi Tap winding at both side switching control. It has a advantage that simple drive of main switching device. and obtain load current of good quality without filter circuit and free from noise or isolation for lower switching frequency. In this research, study on current type converter and inverter circuit that consist for possibility of AC-DC/DC-AC multi-level reversible converter.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권4호
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• pp.195-200
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• 2005

In this paper, we proposed the electric circuit using one common arm of H-Bridge Inverters to reduce the number of switching component in multi-level inverter combined with H-Bridge Inverters and Transformers. and furthermore we suggested the new multi-level PWM inverter using PWM level to reduce THD(Total Harmonic Distortion). and we used the switching method that can be same rate of usage at each transformer. Also, we tested the proposed prototype 9-level inverter to clarify the proposed electric circuit and reasonableness of control signal for the proposed multi-level PWM inverter.

• Journal of Power Electronics
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• 제16권2호
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• pp.490-497
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• 2016

The analysis of the switch status of each unit module of a cascaded multi-level inverter reveals that the working condition of the switch of a chopper arm causes unnecessary switching under the conventional unipolar sinusoidal pulse width modulation (SPWM). With an increase in the number of cascaded multilevel inverters, the superposition of unnecessary switching gradually occurs. In this work, we propose an improved SPWM strategy to reduce switching in cascaded multilevel inverters. Specifically, we analyze the switch state of the switch tube of a chopper arm of an H-bridge unit. The redundant switch is then removed, thereby reducing the switching frequency. Unlike the conventional unipolar SPWM technique, the improved SPWM method greatly reduces switching without altering the output quality of inverters. The conventional unipolar SPWM technique and the proposed method are applied to a five-level inverter. Simulation results show the superiority of the proposed strategy. Finally, a prototype is built in the laboratory. Experimental results verify the correctness of the proposed modulation strategy.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.916-917
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• 2008

In this paper, Switching damage of switches that is used to proposed power conversion system is reduced by soft switching way. dissipation by part resonance and my resonance stress for resonance of resonance circuit are decreased. Is acted by conversion system high effectiveness. Have following characteristic. Design snubber circuit that is used by switch protection in existent hard work rate Topology by resonant circuit for sogt switching, circuit structure was simple and control system is easy. Also, Can generate free output voltage by multi level Tuesday of output that use individuation Power Cell's Phase Shift PWM, and Low-end switching frequency the harmonic is few.

• 전기학회논문지
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• 제62권9호
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• pp.1240-1248
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• 2013

This paper describes a switching-level operation analysis of BTB(Back-To-Back) converter for HVDC(high voltage DC) application based on MMC(modular multi-level converter). A switching-level operation analysis for BTB converter is very important to understand the converter operation in detail and check the voltage and current transients in each components. However, the development of switching-level simulation model for the actual size BTB Converter is very difficult because the MMC normally has more than 150 sub-modules for each arm. So, a switching level simulation model for the 11-level MMC-based BTB converter was developed with PSCAD/EMTDC software, which has 12 sub-modules for the positive arm and another 12 sub-modules for the negative arm. The DC-voltage balance algorithm, the circulating-current reduction algorithm, the harmonic reduction algorithm, and the redundancy operation algorithm were included in this simulation model. The developed simulation model can be utilized to analyze the MMC-based BTB converter for HVDC application in switching level and to develop the protection scheme for the MMC-based BTB converter for HVDC application.