• 조명전기설비학회논문지
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• 제14권6호
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• pp.12-17
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• 2000

IN induction heating system the high frequency operation allows a rapid response to current fluctuation in the inverter and result in improved welding quality. To work induction heating of nonferrous metals, a welding power supply is need high working frequency and high power. This paper is shown design technique for increasing working frequency in induction heating for welding coppers. A series-parallel resonate inverter consists of H-type bridges, each of whose arms is composed of a combination of two parallel IGBTs. Inverter operating with the fixed frequency is controlled by pulse width modulation (PWM). As switching adapted the Zero-Voltage Switching technique to reduce switching losses the system is high efficiency. The propose inverter has feature which is high efficiency for very wide load variations with a narrow range of duty cycle ratio control and load short circuit capability. Detailed experimental results obtained from a 48[V] output, 500[W] experimental inverter are presented to verify the concept.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1991년도 추계학술발표회논문집
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• pp.75-79
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• 1991

In this study, a new sinusoidal PWM inverter suitable for use with power MOSFETs is described. The output waveforms in the proposed OWM inverter are investigated both theoretically and experimentally. A modulating signal for the three-phase PWM inverter is obtained by adding 3nth harmonics to the conventional three-phase sine wave. By using the new modulating signal, the amplitude of the fundamental component is increased about 15 percent more than that of a conventional sine wave inverter and the commutation number of the inverter is decreased to two-thirds of a conventional one.

• 조명전기설비학회논문지
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• 제22권7호
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• pp.28-36
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• 2008

This paper presents a novel prototype of zero current switching pulse frequency modulation (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-fed 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.

• 대한전기학회논문지
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• 제36권12호
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• pp.856-867
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• 1987

Microprocessor control of power-electronic equipment offers the possibility of improvements in manufacture, realizability, maintenance and servicing, and increased control flexibility. In this paper, simple microprocessor control with a view to approximating the polynomial equations which govern the commutation angles was consisdered. The theoretical analysis of this principle which govern the commutaton of power switches in order to cancel any predetermined harmonics and vary the fundamental rms voltage of the inverter output is described. Also the spectrum and harmonics were analyzed by HP-1000 computer. Practical aspect of the realization of a voltage controller based on a microprocessor and a suitable system for variable frequency inverter were also presented. The experimental test has been carried out on a Z-80 microcomputer and a single phase transistor inverter. The various results show the feasibility of obtainintg practically a single phase and a three phase inverter waveforms, which are highly desirable in most inverter applications.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권8호
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• pp.475-481
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• 2002

In this paper the new converter topology using single-Phase full bridge inverter for the switched reluctance motor drives is proposed. The proposed SRM drives are supplied by the AC pulse voltage source, while the conventional drives are supplied by the DC voltage source. Speed of the SRM is controlled by adjusting the frequency and the multitude of output current of inverter. The SRM using the proposed converter reduces the switching loss and the machine core loss, and has ability to pre-regulate the input voltage. The total number of power switches become fewer than another topology as a number of stator poles becomes more. Power circuit of an inverter is simpler and its volume is smaller because the module device involving several switches is used as an inverter.

• 전기학회논문지
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• 제58권12호
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• pp.2359-2369
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• 2009

The study on the multi-level inverter has been increasingly progressing to reduce the switching loss and improve the THD of output current in photovoltaic inverter. Recently, the main topics of multi-level inverter are to reduce the number of devices maintaining the power quality. Therefore, the novel topology was proposed for these problem which is composed of the isolated H-bridge multi-level inverter using the three phase low frequency transformer. The proposed multi-level inverter may not be need for a independent DC power, diode and capacitor. Specially, It has a advantage in generating high voltage source. The proposed approach is verified through simulation and experiment.

• 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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• 제13권1호
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• pp.22-32
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• 2008

본 논문에서는 전철 구동용 견인 전동기의 구동을 위한 과변조 영역에서의 NPC형 3-레벨 인버터의 출력전압 선형화 기법을 제안한다. 과변조 영역은 Modulation Index: MI에 따라서 2가지 모드로 나누었으며 과변조영역 I에서는 퓨리에 시리즈를 통한 기본파성분의 크기로 유도된 reference angle을 사용하였다. 과변조영역 II에서는 과변조영역 I과 같은 방법으로 holding angle을 구하여 사용하였다. 이 두 가지 과변조기법을 통하여 PWM 인버터 출력전압을 1펄스 모드까지 선형적으로 획득할 수 있다.

• Journal of Power Electronics
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• 제10권2호
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• pp.146-154
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• 2010

In this paper two dual output current-type inverters are proposed. These inverters have been called a current source nines-witch inverter and a current-type z-source nine-switch inverter by the authors. The proposed inverters have two independent current source outputs. Compared to two independent current source inverters, the proposed converters are implemented with fewer semiconductor switches. Space vector modulation (SVM) is proposed for these converters. Simulation results show the validity and performance of the proposed inverters.

• 전력전자학회논문지
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• 제11권6호
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• pp.489-493
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• 2006

이 논문의 목표는 최적의 효율을 갖는 PLS 구동 인버터 회로를 설계하는 것이다. 일반적으로 펄스로 구동되는 PLS가 높은 광변환 효율을 갖는다고 알려져 있다. 낮은 듀티비의 펄스를 만들 수 있는 회로로는 E급 공진형 인버터와 세미브리지 인버터가 있다. 이 논문에서는 위의 두 회로의 손실을 분석한다. 손실분석을 확인하기 위해서 220V 380W 입력소비전력을 갖는 인버터 회로를 제작하고 시험하였다. 실험결과를 통해서 높은 효율의 PLS 시스템을 확인했다.