• 마이크로전자및패키징학회지
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• 제15권3호
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• pp.19-25
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• 2008

본 논문에서는 고역률과 고효율로 동작하는 새로운 스텝-업 AC-DC 초퍼에 대해 제안한다. 제안한 초퍼는 전류 불연속제어로 구동되고, 스위치의 듀티율 일정제어에 의해 입력전류는 교류 입력전압의 크기에 비례된 불연속적인 정현파 형태로 주어진다. 그 결과 입력역률은 거의 단위역률로 되고, 듀티율 일정제어에 의해 제안한 초퍼는 제어기법이 간단하게 된다. 일반적으로 전류불연속 제어에 의한 초퍼의 경우, 사용된 스위치의 턴-온 동작은 영전류 스위칭으로 되는 장점이 있지만, 스위치의 턴-오프 동작은 최대 전류에서 스위칭되어 스위칭 손실을 증대시키고 스위치의 과중한 스트레스를 가져오게 된다. 이것은 AC-DC 초퍼의 효율을 저하시키는 요인이다. 본 논문에서는 부분공진기법에 의한 새로운 소프트 스위칭 회로가 설계되어 사용된 제어스위치들의 턴-온, 턴-오프 동작을 소프트 스위칭으로 만들어 초퍼의 효율을 증대시킨다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.169-170
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• 2014

본 논문에서는 높은 역률을 가지는 PFC(Power Factor Correction) 컨버터와 높은 고주파 전압을 발생시키는 단상 하프브리지 인버터를 채용한 오존발생기를 소개한다. PFC 컨버터를 채용하여 기존의 오존발생기용 전원장치에 비해 입력 역률, 전원공급체계와 보호 장치를 개선하였으며, 3kW급의 프로토타입을 구현하고 시뮬레이션 및 실험을 통하여 전원장치의 안정성 및 입력에 대한 높은 역률(0.99이상)을 확인하였다.

• 전기학회논문지
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• 제65권7호
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• pp.1311-1315
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• 2016

Induction motor requires a rotating magnetic field for rotation. Current required to generate the rotating magnetic field is immediately magnetizing current. This magnetizing current is associated with the reactive power. Induction motor is always required reactive power. If reactive power is supplied only to the power supply side, the power factor is low. Therefore, it is to compensate the power factor by connecting capacitors in parallel to the motor terminal. If the capacitor current is greater than the magnetizing current of the motor, there is a possibility that the self-excitation occurs. High voltage generated by the self-excitation leads to insulation failure on the motor. So it is necessary to calculate the power factor correction capacitor capacity the most suitable to the extent that the magnetizing current does not exceed the capacitor current. In this study, we first computed the magnetization current and the reactive power of the induction motor and then calculates a limit of the maximum power factor by comparing the magnetizing current and the capacitor current installed in order to achieve the target power factor.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권1호
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• pp.45-49
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• 2004

A method for obtaining the power energy with high quality is to keep the power factor for a load as close to unity as feasible. In this paper, we present a new method to improve the power factor for a load. The proposed method uses fuzzy control techniques in order to determine how many parallel capacitors are to be connected to the load for the correction of the power factor.

• 전기학회논문지P
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• 제62권3호
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• pp.145-150
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• 2013

A novel AC to DC PWM converters with unity input power factor are proposed to overcome the above shortcoming. The main function of these converters is to shape the input line current to force it exactly in phase with the input AC voltage. Therefore, the input power factor can be improved to near unity and the input current harmonics can be eliminated. In this paper, half-bridge converter with two active switches and two diodes are utilized for low-cost type UPS configuration. By having only two semiconductors in the current path at any time, losses can be reduced over the conventional boost topology. Also, this converter provides controllable dc-link voltage, high power factor, and low cost type converter by simple power circuits. Simulation results show that the proposed half-bridge converter/inverter control technique can be applied to single-phase low-cost type UPS systems successfully.

• 전력전자학회논문지
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• 제12권6호
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• pp.510-516
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• 2007

본 논문에서는 더 높은 에너지 효율을 요구하는 전자 기기들의 사용에 따른 고전력 밀도 AC/DC adapter를 위한 향상된 제어 방법을 제안한다. PFC (Power Factor Correction) 토폴로지는 BCM (Boundary Conduction Mode)제어 방식을 적용한 부스트 토폴로지를 기본으로 하였으며, DC/DC 토폴로지는 50% 고정 duty법과 함께 새롭게 제안된 Off-time 제어법을 적용한 하프브릿지 토폴로지를 기본으로 하였다. 이는 반도체 소자와 마그네틱 소자의 크기를 줄이는데 용이하다. 85W급 AC/DC 어뎁터(18.5V/4.6A)를 설계하여 실험한 결과 90%의 효율과 $36W/in^3$의 전력밀도가 측정되었고 무부하시 전력 손실은 0.5W를 달성하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.363-364
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• 2016

In this paper, a novel bridgeless interleaved power factor correction circuit with single current sensor is proposed. The proposed control strategy requires only one current sensor for the interleaved bridgeless PFC. By sampling the output current, all the boost indictor currents can be calculated and used to control the input current according to the input voltage. The reduced number of current sensors and associated feedback circuits helps reduce the cost of system. The problem caused by the unequal current gain between current sensors inherently does not exist in the proposed topology. Thus, current sharing between converters can be achieved more accurately and the high frequency distortion is decreased. In addition, the proposed technique can be applied to the other kinds of interleaved PFC topologies. Performance of the proposed control strategy is verified by the experimental results with 6.6kW bridgeless interleaved PFC circuit.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.355-357
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• 1996

With the wide-spread use of rectifier in electronic equipments, such problems as electronic components failures or equipment disorders have been occurred due to current harmonics. To overcome these problems, power factor correction circuits employing boost converter have been used. The switching stress of boost converter can be reduced by snubber circuit. Recently, research activities in snubber circuits have been directed to energy recovery snubber for improving the efficiency of power converter. In this study, a new passive snubber circuit which can recover trapped snubber energy without added control is proposed for boost converter The control of boost converter with proposed snubber is the same as the conventional one. In addition, the energy recovery circuit can be implemented with a few passive components. The circuit operation is confirmed through simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.247-250
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• 1997

A novel zero-voltage-switching(ZVS) isolated PWM converter for single stage power factor correction (PFC) is presented to improve the performance of the previously presented ZVT converter[5]. A simple clamp circuit in the primary side provides zero-voltage-switching condition to all semiconductor devices. This ZVS is achieved with minimum device voltage and current stresses. Operation principle, control strategy and features of the proposed converter are presented and verified by the experimental results from a 1.5 ㎾, 100 KHz laboratory prototype

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.988-991
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• 1992

A new zero voltage switching PWN converter family is presented by using a new ZVS PWN module (ZPM) with a saturable inductor which prevents diode junction capacitors and a commutation inductor from resonating. The new converters show almost all characteristics of the conventional PWN converters. A boost ZVS PWN converter is applied to a power factor correction circuit. It operates on an continuous conduction mode. Experimental results for output power of 1kW are presented.