• Journal of Power Electronics
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• 제10권2호
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• pp.138-145
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• 2010

This paper presents a single phase multilevel inverter for using as a voltage harmonic source. First, a single phase multilevel inverter system is presented and the structural parts of the inverter are described. In order to obtain multilevel output voltage waveforms, a switching strategy based on calculating switching angles is explained and an improved formula for determining switching angles is given. Simulation and experimental results of multilevel voltage waveforms are given for 15, 31 and 127 levels. The proposed topology does not only produce output voltages with low THD values. It also produces the required harmonic components on the output voltage. For this purpose, equations for switching angles are constituted and the switching functions are obtained. These angles control the output voltage as well as provide the required specific harmonics. The proposed inverter structure is simulated for various functions with the required harmonic components. The THD values of the output voltage waves are calculated. The simulated functions are also realized by the proposed inverter structure. By using a harmonic analyzer, the harmonic spectrums, which belong to the output voltage forms, are found and the THD values are measured. Simulation and experimental results are given for the specific functions. The proposed topology produces perfectly suitable results for obtaining the specific harmonic components. Therefore, it is possible to use the structure as a voltage harmonic source in various applications.

• 전력전자학회논문지
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• 제10권1호
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• pp.78-86
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• 2005

최근 들어, 저전압·대전류 출력 특성을 갖는 연료전지를 위한 새로운 발전시스템이 주목받고 있다. 연료전지 발전시스템에서는 dc-dc 승압용 컨버터와 dc-ac 인버터가 필요하다. 그러므로 본 논문에서는 연료전지 발전시스템을 위한 ZVS 동작을 가진 dc-dc 능동 클램프 전류형 하프 브리지 컨버터를 제안하였다. 제안된 컨버터는 일반적인 dc-dc 컨버터에 비해 높은 효율과 높은 소자 이용율을 가진다. 연료전지 발전시스템은 연료전지(PEMFC)의 낮은 전압(28∼43[Vdc])을 380[Vdc]로 승압하기 위한 능동 클램프 전류형 하프 브리지 컨버터로 구성하였다. 단상 풀 브리지 인버터는 220[Vac], 60[Hz] 교류 출력을 얻기 위해 적용하였다.

• 전력전자학회논문지
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• 제24권6호
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• pp.459-462
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• 2019

This work presents methods for reducing overshoot voltages across the drain-source of silicon carbide (SiC) MOSFETs in grid-connected hybrid active neutral-point-clamped (ANPC) inverters. Compared with 3-level NPC-type inverter, the hybrid ANPC inverter can realize the high efficiency. However, SiC MOSFETs conduct its switching operation at high frequencies, which cause high overshoot voltages in such devices. These overshoot voltages should be reduced because they may damage switching devices and result in electromagnetic interference (EMI). Two major strategies are used to reduce the overshoot voltages, namely, adjusting the gate resistor and using a snubber capacitor. In this paper, advantages and disadvantages of these methods will be discussed. The effectiveness of these strategies is verified by experimental results.

• 전력전자학회논문지
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• 제16권2호
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• pp.105-113
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• 2011

태양광 발전 시스템이 대용량화됨에 따라 태양전지 어레이 구성 시 부정합(mismatch) 문제가 대두되는 가운데, 태양전지 모듈을 직접 계통에 연계하는 AC 모듈형 태양광 모듈 집적형 전력변환장치(PV-MIC)에 관한 연구가 지속되고 있다. PV-MIC는 수명 및 고효율이 가장 큰 문제이며 이 문제를 해결하기 위해서 본 논문에서는 ZVS 동작을 통하여 스위칭 손실을 저감시키고 입력전류 리플감소를 통하여 입력 커패시턴스를 저감할 수 있는 능동 클램프 전류원 하프 브릿지 컨버터를 적용한 PV-MIC를 제안하고, 이에 관한 제어분담 및 설계에 대하여 고찰한다.

• 전기학회논문지P
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• 제65권2호
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• pp.114-121
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• 2016

This paper is Instant space vector PWM(Pulse Width Modulation)power conversion devices in switching power semiconductors from my generation to losses and switching when the voltage surge and current surge of electronic noise(EMI: Electro Magnetic Interference / RFI: Radio Frequency Interference)to effectively minimize the power soft-switching power conversion circuit topologies of auxiliary resonant DC tank for the purpose of high performance realization of the electric power conversion system by the high-speed switching of a semiconductor device(AQRDCT simultaneously : an active auxiliary resonance using auxiliary Quasi-resonant DC tank)DC link snubber switch has adopted a three-phase voltage inverter. AQRDCL proposed in this paper can reduce the effective and current peak stress of the power semiconductors of the auxiliary resonant snubber circuit compared to the conventional active-resonant DC link snubber, it is not necessary to install the clamp switch of the auxiliary resonant DC link, DC the peak current and power loss of the bus line can be reduced.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.216-225
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• 2006

This paper presents a new circuit topology of DC busline switch and snubbing capacitor-assisted full-bridge soft-switching PWM inverter type DC-DC power converter with a high frequency link for low voltage large current applications as DC feeding systems, telecommunication power plants, automotive DC bus converters, plasma generator, electro plating plants, fuel cell interfaced power conditioner and arc welding power supplies. The proposed power converter circuit is based upon a voltage source-fed H type full-bridge high frequency PWM inverter with a high frequency transformer link. The conventional type high frequency inverter circuit is modified by adding a single power semiconductor switching device in series with DC rail and snubbing lossless capacitor in parallel with the inverter bridge legs. All the active power switches in the full-bridge inverter arms and DC busline can achieve ZVS/ZVT turn-off and ZCS turn-on commutation operation. Therefore, the total switching losses at turn-off and turn-on switching transitions of these power semiconductor devices can be reduced even in the high switching frequency bands ranging from 20 kHz to 100 kHz. The switching frequency of this DC-DC power converter using IGBT power modules is selected to be 60 kHz. It is proved experimentally by the power loss analysis that the more the switching frequency increases, the more the proposed DC-DC converter can achieve high performance, lighter in weight, lower power losses and miniaturization in size as compared to the conventional hard switching one. The principle of operation, operation modes, practical and inherent effectiveness of this novel DC-DC power converter topology is proved for a low voltage and large current DC-DC power supplies of arc welder applications in industry.

• 대한전자공학회논문지SD
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• 제37권1호
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• pp.19-28
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• 2000

고장에 대한 강인성, 높은 출력 전류 특성 및 모듈화의 용이성 때문에 병렬 인버터 시스템은 그활용도가 점차 높아지고 있다. 이러한 병렬 인버터 시스템에서 전체 시스템 전력균형 제어는 주로 주파수 드롭과 전압 드룹 제어 또는 유효전력 과 무효전력 제어를 통하여 이루어지고 있다. 그러나 이러한 제어방법들은 시스템 변수 변동 및 부하변동에 따라 늦은제어 응답특성을 가지는 단점을 가지고 있다. 이러한 단점을 해결하기위해, 본논문에서는 병렬 인버터 시스템의 각모듈 출력전력을 균등화 시키는 새로운 제어기를 제안하였다. 제안한 제어기는 하드웨어 구현의 용이성, 피크전류 차단 기능들의 특성을 가진다. 또한 본논문에서는 제안한 제어기의 설계 절차를 기술하였으며, 여러 부하조건 및 시스템 파라미터 변동조건에 따라 순시전력균형제어기 동작 특성의 효용성을 컴퓨터 시뮬레이션 및 실험을 통하여 확인 하였다.

• 전기학회논문지
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• 제58권1호
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• pp.77-85
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• 2009

With the advent of power semiconductor switching devices, power electronics relating to high frequency electromagnetic eddy current based induction heating technology have become more suitable and acceptable. This paper presents high-frequency induction heating cooking appliance circuit based on the zero current switching-PWM single ended push-pull(ZCS-PWM SEPP) resonant inverter added AC-DC converter. This inverter uses pulse-width-modulation(PWM) control method with active auxiliary quasi-resonant lossless inductor snubbers and a switched capacitor. To improved the transient performance, the PI controller is applied for this system. For the systematic parameter optimization of the PI controller, the gradient-based optimization algorithm is applied. The performance of optimized parameters is evaluated using simulation and experimental test. These results show that the proposed systematic optimal tuning method improve the transient performances of this system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.463-465
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• 2005

This paper proposes a regeneration inverter system, which can regenerate the excessive power form the DC bus line to the AC source for traction systems. The proposed regeneration inverter system for DC traction can reduce harmonics which is a characteristic of the AC current source. The simulation was composed as a prototype model[3.7kW]. Finally, it is shown that the inverter can successfully operate in regeneration mode.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1065-1067
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• 2000

This paper describes performance analysis of ARCP Inverter, which can offer zero voltage switching at nominal voltage stress. The system consists of a voltage-source inverter with sort-switching module. Each main switch is connected in parallel with resonant capacitor and two auxiliary switches are placed in series with a resonant reactor for soft-switching capability. The described ARCP inverter could be effectively applied for active power filter reactive power compensator, and UPS.