• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1990년도 추계학술발표회논문집
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• pp.47-52
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• 1990

This paper presents a cyclocoverter with a LC resonant circuit for a induction motor dr-ive. The cycloconverter can provide variab-le voltage and frequency three phase output while keeping the input displacement factor at 1.0. The input current wave forms are sinusoidal, and the wide output frequency ran-ge is appropriate for variable speed AC motor drives.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.518-521
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• 1989

Recently, PWM cycloconverters that are frequency conversion system have been studied for eliminating do links of conventional converter and inverter systems. A new real-time method for generating PWM patterns is proposed in this paper. This method realizes sinusoidal input and output currents, controllable input displacement factor regardless of load power factor, and maximum output voltage range. Finally, feasibility of the proposed method is confirmed by simulation and experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.140-143
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• 1988

In this study, so called high frequency cycloconverter which converts commercial so power source directly to high frequency power source is proposed. In this system, the circulating current play very important role. Its state and magnitude effects on system characteristics. This paper deals with the control method of the circulating current and side band component analysis of high frequency side current which is produced by it.

• 대한전기학회논문지
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• 제38권6호
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• pp.431-440
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• 1989

This paper proposes a new PWM cycloconverter which can step up input voltage. With input reactors ac power supply acts as current source, and with output capacitors the balanced output voltage is build-up. The converter is modeled with fourth order state equation using dq transformation and the steady state characteristics are evaluated. It is shown that the proposed converter can generate the output voltage 2-5 times greater than input voltage. The output voltage and input current have sinusoidal and smooth waveforms and the converter is capable of voltage build-up. The characteristics of the proposed converter is verified simulation and experiment.

• 전자공학회논문지S
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• 제35S권9호
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• pp.111-117
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• 1998

본 논문은 LC공진회로를 이용한 사이크로컨버터의 휴지기간 없는 극성절환 방법에 관한 것이다. 제안한 방법에 따르면 극성절환시 회로단락을 방지하기 위한 휴지기간이 요구되지 않는다. 따라서 제어지연 및 출력전류의 고조파성분이 감소하게 된다. 그리고 제안한 방법은 비순환전류형의 다른 자연전류형 사이크로컨버터에도 확장될 수 있다. 본 논문에서는 휴지기간 없는 극성절환의 스위칭 방법에 대하여 검토하였으며 제안한 방법의 유용성을 확인하기 위하여 LC공진회로를 이용한 사이크로콘버터에 적용실험을 수행하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1985년도 하계학술회의논문집
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• pp.313-314
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• 1985

• 대한전기학회논문지
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• 제36권5호
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• pp.352-359
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• 1987

The cycloconverter operating on a circulating current-free mode has many zero crossing points. If an exact zero crossing points are not detected, the three phase-unbalanced currents will flow in a motor. In this paper, the current feedback using a current reference wave is proposed to improve the problems of zero crossing detection, three phase-unbalanced voltages, currents, and torgue ripples. To prevent the saturation of the air gap flux and keep the torque constant, the constant voltage / hertz control with IR compensation is adopted. The PI-controller is designed using the linearized model of the cycloconverterinduction motor system. Alsi, Z-80A single board computer has been used to implement the proposed scheme which results in the performance improvement of cycloconterter-fed induction motor speed control system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.283-286
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• 1988

This paper describes the PWM cycloconverter which can provide step-up ac-ac direct conversion in a wide output frequency range. With input reactor and output capacitor. the input and output ports are exchanged. And sine PWM scheme is applied to the converter. To analyze the converter operation the state equations are derived using dq transformation. Simulated results show that both the output voltage and frequency can be controlled by adjusting the modulating functions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.202-204
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• 1993

Appropriate control of real and reactive power flowing in and out from system can lead to considerable benefits : network stabilization, load leveling, voltage regulation etc. This paper presents how to control real and reactive power flow between an flywheel energy storage system and a power three phase network. The system compensating real and reactive power consists of control system and cycloconverter operating in the four quadrant modes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.797-799
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• 1993

In this paper, we propose a new PWM control method of cycloconverter with a resonant circuit for induction heating. The proposed new PWM control method determines the switching duty ratio compared the integrated value of load current with the reference value of input current on sampling interval. By the Proposed method, the displacement factor becomes 1.0 and the input current waveforms become sinusoid which is nearly 1.0 in terms of the input power factor. To confirm the validity of the proposed method, the simulations and experiments are carried out.