• Journal of Power Electronics
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• 제6권4호
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• pp.356-365
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• 2006

This paper presents an improved three-phase PFC power rectifier with a three-phase diode rectifier cascaded four-switch boost converter. Its operating principle contains the operating principle of two conventional three-phase PFC power rectifiers: one switch boost converter type and a two switch boost converter type. The operating characteristics of the four switch boost converter type three-phase PFC power rectifier are evaluated from a practical point of view, being compared with one switch boost converter type and two switch boost converter topologies.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권6호
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• pp.396-401
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• 2004

Single phase induction motor(SPIM) is one of the most widely used type of low power AC motors in the world, especially for domestic or commercial applications where a three phase power supply is not available. Single phase induction motors have no starting torque their own. So there are several ways of starting single phase induction motors. The most common type is the starting capacitor installed in series with the auxiliary winding to increase the starting torque. In the conventional systems, this function is conducted by a centrifugal switch. But the mechanical centrifugal switch has many problems such as switch malfunction. This paper presents the auxiliary winding control using digital universal starting switch to overcome these shortcomings of centrifugal switch.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.663-667
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• 1998

This paper describes for reducing harmonic distortion on CO2 welding machine with nonlinear load characteristic using single-switch three-phase AC/DC converter. The low-order harmonic component amplitude of the phase current of single-switch three-phase discontinuous mode is calculated. Experimental results show that CO2 welding machine with single-switch three-phase AC/DC converter is effectively controlled with power factor correction for phase current during welding time.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.905-915
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• 2015

Two PWM techniques using space vector pulse-width modulation (SVPWM) are proposed for a two-phase permanent magnet synchronous motor (PMSM) driven by a two-phase eight-switch inverter. A two-phase motor with two symmetric stator windings is usually driven by a two-phase four-, six-, or eight-switch inverter. Compared with a four- and six-switch inverter, a two-phase eight-switch inverter can achieve larger power output. For two-phase motor drives, the SVPWM technique achieves more efficient DC bus voltage utilization and less harmonic distortion of the output voltage. For a two-phase PMSM fed by a two-phase eight-switch inverter under a normal SVPWM scheme, each of the eight PWM trigger signals for the inverter have to be changed twice in a cycle, causing a higher PWM frequency. Based on the normal SVPWM scheme, two effective SVPWM schemes are investigated in order to reduce the PWM frequency by rearranging four comparison values, while achieving the same function as the normal PWM scheme. A detailed explanation of the normal and two proposed SVPWM schemes is illustrated in the paper. The experimental results demonstrate that the proposed schemes achieve a better steady performance with lower switching losses compared with the normal scheme.

• 전기학회논문지P
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• 제60권1호
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• pp.48-52
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• 2011

Over the years, traditionally, six-switch three-phase inverters have been widely utilized for variable speed alternating current motor drives. Recently, some efforts have been made on the application of four-switch three phase inverter for uninterruptible power supply and variable speed drives. This is due to some advantages of the four-switch three phase inverter over the conventional six-switch three-phase inverters such as reduced price due to reduction in number of switches, reduced switching losses, reduced number of interface circuits to supply logic signals for the switches, simpler control algorithms to generate logic signals, less chances of destroying the switches due to lesser interaction among switches, and less real-time computational burden. However such as slow di/dt and speed limitation, are the inherent characteristics and main drawbacks of the four-switch configuration. Those problems can be overcome in conjugation with Voltage-doublers which has additional advantage, such as unity power factor correction.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.267-270
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• 2002

Fractional horse power single phase induction motors have no starting torque their own. So there are several ways of starting single phase induction motors. The most common type is the starting capacitor installed in series with the auxiliary winding to increase the starting torque. Also, the auxiliary winding is disconnected once the speed of the motor reaches 70 to 80 [%] of the rated speed. In the conventional systems, this function is conducted by a centrifugal switch. But the mechanical centrifugal switch has many problems such as switch malfunction. This paper presents the new methods of electronic starting switch by inductor to overcome these shortcomings of centrifugal switch.

• 전기전자학회논문지
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• 제14권3호
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• pp.232-235
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• 2010

기존의 수동 스위치를 사용한 스위치-라인 타입 위상변화기의 수동 스위치를 스위칭 증폭기로 대체한 60GHz CMOS 능동위상변화기를 소개하였다. 능동스위치 위상변화기는 능동스위치 블록과 수동 딜레이 네트워크 블록 구성되며, 기존의 vector-sum 위상변화기와 비교해 간단한 회로 구성이 가능하다. 능동스위치 블록은 On-Off state에 따라 다르게 요구되는 입출력 저항을 고려하여 설계하였고, 수동 딜레이 네트워크 블록은 회로의 크기를 최소화하기 위하여 일반적인 microstrip line 대신 lumped 인덕터와 커패시터를 사용하여 구성하였다. TSMC 65nm CMOS 공정을 이용하여 1-bit 위상변화기를 제작 및 측정하였으며, 그 결과 65GHz에서 평균 -4.0dB 의 삽입손실과 120도의 위상차를 얻었다.

• 한국전자통신학회논문지
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• 제10권3호
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• pp.365-373
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• 2015

기존 6스위치 3상 인버터(SSTPI)의 한 상을 스위치 대신 커패시터로 대체한 4스위치 3상 인버터(FSTPI)에서 양 커패시터 전압의 불평형에 의한 출력전압의 오차를 보상하는 것은 FSTPI의 성능을 결정하는 중요한 요소이다. 본 논문에서는 DC 오프셋 전류 주입에 의하여 FSTPI의 커패시터 전압 불평형을 보상하는 새로운 방법과 FSTPI에 적용할 수 있는 간략화된 SVPWM 방법을 제안한다. 제안된 방법은 컴퓨터 시뮬레이션을 통해 타당성을 검증하였다.

• 한국전자통신학회논문지
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• 제11권3호
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• pp.283-292
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• 2016

6스위치 3상 인버터(SSTPI)의 한 상을 스위치 대신 커패시터로 대체한 4스위치 3상 인버터(FSTPI)에서 커패시터 전압의 불평형으로 인한 출력 전압의 오차를 보상하는 방법과 전압 제어 방법은 FSTPI의 성능을 결정짓는 중요한 요소이다. 본 논문에서는 DC 오프셋 전류 주입 통한 FSTPI의 커패시터 전압의 불평형을 보상하는 새로운 방법과 FSTPI의 새로운 전압 제어 방법인 간략화 된 SVPWM을 제안한다. 제안된 방법은 FSTPI로 SPMSM를 구동하는 시뮬레이션과 실험을 통해 그 타당성을 검증하였다.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.1107-1115
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• 2013

A new PWM technique for a two-phase BLDC motor fed by a two-phase eight-switch inverter is proposed in this paper. It is well known that a two-phase eight-switch inverter can significantly improve power output compared with a two-phase six-switch inverter in a two-phase motor drive. To drive the two-phase BLDC motor simply and effectively, two normal PWM strategies are investigated to manage speed regulation. However, under the conditions of low speed and light load, especially during the braking process, the current in a short time of one period is near zero, which is a discontinuous waveform every half period. To solve it, a novel PWM technique is investigated to improve the operational performance of normal technique. Using the new PWM scheme, the current continues every half period and the braking performance is improved. The effectiveness of the proposed PWM method is verified through the experiments.