• 전력전자학회논문지
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• 제8권6호
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• pp.478-487
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• 2003

본 논문에서는 고압 대용량 전동기 구동용 멀티레벨 인버터의 종류 및 특징을 간략히 살펴보고, 특히 입출력 전력품질이 우수하고 전압별 시리즈화가 용이한 H-브릿지 멀티레벨 인버터의 구조적 특징 및 장점을 기술하였다. 연구 개발된 3,300V lMVA 용량의 Cascaded H-브릿지 멀티레벨 인버터의 구체적인 전력회로 구조 및 설계방법, 제어기 구성 그리고 PWM 기법을 제시하였다. 또한, 실용량의 시험을 통해 H-브릿지 멀티레벨 인버터는 출력 전압 Step이 여러 단계이고 dv/dt가 적으며 입력단 THD를 크게 낮출 수 있어 성능 면에서도 여타 방식보다 우수함을 입증하였다. 또한 생산적인 측면에서도 저압 소자를 사용하여 설계하므로 기존의 생산/시험 기술과 설비를 이용할 수 있어 매우 경제적이며 Power Cell 단위 결합 구조이므로 신뢰성 측면이나 보수/유지 측면에서도 유리하다는 결론을 얻었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.562-564
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• 2008

This paper deals with the three phase high voltage power-grid connection topology using multi-level inverter. Due to the multi-level inverter, these are improved effect of fluctuating voltage, problem of EMC and switching loss using suitable switching patterns of device, above all thing, it is easy to realize the system because of using lower voltage rating switch. This topology can be applicable to power-grid connection of wind system, there is a good point about economical efficiency. The simulation results are presented to verify the validity of the proposed topology.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.294-296
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• 2000

Energy recovery in the regenerative region is very important when SRM(Switched Reluctance Motor) is used in traction drive. This is because that to reduce energy loss during mechanical braking and/or to have a high efficiency drive during braking. To control excitation voltage in motor operation and regenerative voltage in the generator operation in the SRM, multi-level voltage control is effective. This paper suggests multi-level inverter which is useful for motoring and regenerative operation in SRM.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.326-332
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• 2018

In this paper, the design process and the control method of the power conversion system (PCS) that consists of a bidirectional DC-DC converter and a 3-level T-type inverter for an energy storage system is presented. Especially the design method of the output LCL filter for a 3-lvel T-type inverter without complex mathematical process are proposed. The validity of the control method and design process in this paper are verified through simulation and experimental analysis.

• 전력전자학회논문지
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• 제10권1호
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• pp.95-101
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• 2005

본 연구에서는 H-Bridge 인버터와 변압기 조합에 의한 다중레벨 인버터로 구성함에 있어 스위칭 소자수를 저감하기 위해 각 H-Bridge 인버터의 한 암을 공통으로 사용할 수 있는 전력회로를 제안한다. 또한 각 인버터에 연결된 변압기의 이용률을 동일하게 할 수 있는 스위칭 방식의 제안으로 각 변압기의 용량을 동일하게 하였다. 제안된 전력회로 및 제어신호의 타당성을 입증하기 위해 프로토 타입 인버터에 대하여 실험을 행하였다

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권5호
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• pp.231-237
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• 2005

Many conventional multi-level inverters have detected switching faults by using the over voltage and current. However, fault detection of the switching elements is very difficult because the voltage and current due to each switching fault decrease more than the normal operation. Moreover, the dc-link unbalancing voltage causes a serious problem in the safety and reliability of system when the 3-level inverter faults occur Therefore, this paper proposes the simple fault diagnose method and the neutral-point-voltage control method that can protect the 3-level inverter system from the unbalancing voltage of the do-link capacitors when the faults of switching elements occur in the 3-level inverter that is very efficient in ac motor drives of the high voltage and high power applications. Through experiment results, the validity of the proposed method is demonstrated.

• Journal of Power Electronics
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• 제16권1호
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• pp.133-141
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• 2016

This paper focuses on the development of a Five-Level Flying-Capacitor Dual Buck Inverter (FLFCDBI) based on the main circuit of dual buck inverters. This topology has been described as not having any shoot-through problems, no body-diode reverse recovery problems and the half-cycle work mode found in the traditional Multi-Level Flying-Capacitor Inverter (MLFCI). It has been shown that the flying-capacitor voltages of this inverter can be regulated by the redundant state selection within one pole. The voltage balance of the flying-capacitors can be achieved by charging or discharging in the positive (negative) half cycles by choosing the proper logical algorithms. This system has a simple structure but demonstrates improved performance and reliability. The validity of this inverter is conformed through computer-aided simulation and experimental investigations.

• 전력전자학회논문지
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• 제8권6호
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• pp.469-477
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• 2003

본 논문은 플라잉 커패시터 멀티-레벨 인버터의 가장 큰 문제점인 플라잉 커패시터 전압 불균형의 새로운 해결방법으로 캐리어 로테이션(Carrier-Rotation) PWM 기법을 제안한다. 제안된 기법은 모든 스위치가 한번의 스위칭동작을 하는 동안 플라잉 커패시터의 충전과 방전에 관계된 레그 전압 리던던시(redundancy)를 같은 비율로 사용하여 플라잉 커패시터 전압을 일정하게 유지하며, 전압의 변동폭이 최소가 되도록 제어한다 이 방법은 각 캐리어의 배치가 모두 통상이므로 출력 전압의 고조파 성분이 저감되며, 또한 모든 스위치의 스위칭 주파수가 같으므로 스위치 이용률이 개선되는 특성을 갖는다. 제안된 기법을 플라잉 커패시터 3-레벨 인버터에 적용하여 상세히 분석하고, 3-레벨 이상에 적용할 수 있도록 일반화한다. 제안된 기법의 타당성은 실험 결과로 검증된다.

• Journal of Power Electronics
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• 제15권6호
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• pp.1508-1516
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• 2015

A single phase H-bridge inverter is employed in conventional Inductive Power Transfer (IPT) systems as the primary side power supply. These systems may not be suitable for some high power applications, due to the constraints of the power electronic devices and the cost. A high-frequency cascaded multi-level inverter employed in IPT systems, which is suitable for high power applications, is presented in this paper. The Phase Shift Pulse Width Modulation (PS-PWM) method is proposed to realize power regulation and selective harmonic elimination. Explicit solutions against phase shift angle and pulse width are given according to the constraints of the selective harmonic elimination equation and the required voltage to avoid solving non-linear transcendental equations. The validity of the proposed control approach is verified by the experimental results obtained with a 2kW prototype system. This approach is expected to be useful for high power IPT applications, and the output power of each H-bridge unit is identical by the proposed approach.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.620-624
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• 2004

Th is paper presents a systematical approach to study carrier based PWM techniques (CPWM) in diode-clamped and cascade multilevel inverters by using the proposed multi-modulating pattern method. This method is based on the vector correlation between CPWM and space vector PWM (SVPWM) and applicable to both multilevel inverter topologies. The CPWM technique can be described in a general mathematical equation, and obtain the same outputs similarly as of corresponding SVPWM. Control of the fundamental voltage, vector redundancies and phase redundancies in multilevel inverter can be formulated separately in the CPWM equation. The deduced CPWM can obtain a full vector redundancy control, and fully utilize phase redundancy in a cascade inverter. In the paper, CPWM equations and corresponding algorithm for generating multi-modulating signals will be performed, in which SVPWM attributes will be presented by corresponding controllable factors.