• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.457-461
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• 2001

Advantages of switched reluctance motor(SRM) drives make it an attractive candidate for replacing adjustable speed ac and dc drives in both industrial and consumer applications. Furthermore, a simple, low cost and robust SRM drive can be efficiently operated in the hostile environment of an automobile. Generally, the speed control of SRM has a large step change or large torque reference, the output of its PI controller is often saturated. When this happens, the integral state is not consistent with the SRM input, while may give rise to the windup phenomenon. This paper proposes anti-windup control method for SRM speed control system by hysteresis current controlled asymmetry bridge converter. The experimental results show that the speed response has much improved performance, such as a small overshoot and fast settling time at the acceleration and particulary deceleration period with braking mode.

• Journal of Power Electronics
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• 제16권4호
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• pp.1483-1493
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• 2016

Multiple parallel inverters have multiple resonant frequencies that are influenced by many factors. This often results in stability and power quality problems. This paper develops a multiple input multiple output model of grid-connected inverter systems using a closed-loop transfer function. The influence factors of the resonant characteristics are analyzed with the developed model. The analysis results show that the resonant frequency is closely related to the number, type and composition ratio of the parallel inverters. To suppress resonance, a scheme based on virtual impedance is presented, where the virtual impedance is emulated in the vicinity of the resonance frequency. The proposed scheme needs one inverter with virtual impedance control, which reduces the design complexity of the other inverter controllers. Simulation and experimental tests are carried out on two single phase converter-based setups. The results validate the correctness of the model, the analytical results and the resonant suppressing scheme.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1492-1501
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• 2015

This paper analyzes the effect of voltage sag on distribution systems due to the connection of Electric Vehicles (EVs). In order to study the impact of the voltage sag on the power system, two scenarios have been selected in this paper. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP). The numbers of EVs are predicted based on the number of vehicles in distribution system of Seoul. In addition, the number of EVs is set up using real-time traffic in Seoul to simulate Scenario I and II. The simulation results show that voltage sag can occur if the distribution system has more than 30% of the total number of vehicles.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 추계학술대회 논문집
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• pp.243-244
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• 2012

ITER 초전도자석 전원공급장치에서 고장의 종류는 단락, 단락 외 컨버터 내부고장 그리고 여러 외부요인에 의한 고장 크게 세 가지로 구분된다. 여기서 단락 외 컨버터 내부고장과 외부요인에 의한 고장은 보호시스템 및 장치의 동작으로 인해 피해가 축소된다. 하지만 단락시에는 보호시스템이 동작하더라도 단락전류가 매우 커 큰 피해를 줄 수 있다. 또한 ITER 초전도자석 전원공급장치는 운전 중 발생 가능한 부하의 단락으로부터 초전도자석 및 다른 장치 등을 보호하기 위하여 ITER에서 요구하고 있는 FSC(Fault Suppression Capability: 고장 억제 능력) 조건을 만족해야 한다. FSC 조건에서 전원공급장치는 출력에서 300 kA의 단락전류가 흐를 경우에도 80 ms(50 Hz, 4주기)동안 전기적 고장 없이 견뎌야 한다. 본 논문에서는 전원공급장치에서 발생될 수 있는 주요 단락 항목을 소개하고, 최악의 조건에서 단락전류에 의한 전원공급장치의 고장해석을 통해 FSC 요건을 만족하는 소자 선정 및 구조설계의 적합성을 검증한다.

• 마이크로전자및패키징학회지
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• 제8권2호
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• pp.43-48
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• 2001

Economical consumption of energy, longer life of lamps, higher lighting comfort and new aesthetic of illumination is subject of numerous research and development works. The halogen lamps are an example of positive solution some of above mentioned problems. The electronic transformers are more frequent used for their supply. In comparison with conventional transformers they have less weight, less volume and 60% less power losses. Their advantages are particular visible, when the hybrid technique is applied. The paper presents the results of engineering research and development works carried out in Private Institute of Electronic Engineering, in R. & D. Center for Hybrid Microelectronics and Resistors and in Technical School of Communications in Krakow, in the field of the design and exploitation tests of hybrid converters 220V AC /12V DC (electronic transformers) and electronic ballasts destined for the supply of halogen lamps 20W to 150W and fluorescent lamps respectively. To perform the converters, thick film technology and surface mount technology were used. For the protection of converter electronic circuit the thick film temperature sensor and transistors were applied. Moreover the paper presents the base application circuits of elaborated converters, their technical parameters and exploitation results. The development perspectives of such domain of hybrid circuits are also discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.982-983
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• 2015

본 논문은 CIGRE 492 보고서를 따른 것으로 최근 해외 선도 기업 및 미국, 유럽, 중국 등에서 도입하고 있는 LCC-HVDC, VSC-HVDC와 기존 송전시스템인 HVAC의 기술 및 경제적 효율성을 비교분석하였다. 분석 방법은 동일한 조건을 설정하여 각 시스템에 모의 적용하였으며, (1) HVAC와 VSC-HVDC와의 비교 (2) LCC-HVDC와 VSC-HVDC와의 비교를 진행하였다. 그 결과 시간 흐름에 따라 AC보다 DC에서의 경제적 효율성을 확인하였고, 또한 HVDC의 전류형과 전압형의 비용 분석에서는 오차범위, 추가적 편익 등을 고려할 시 전압형의 경제성에 대한 긍정적 측면을 확인할 수 있었다. 본 연구에서는 일반적인 PWM 방식을 택하였으나, 추후 연구에서는 최근 선도 기술이라 평가받는 MMC 방식의 전압형 HVDC를 적용하여 연구하고자 한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.437-442
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• 2001

계통연계형 태양광 발전 시스템은 태양 에너지를 전기 에너지로 변환하는 태양 전지부와 발생 전력을 계통에 연계하는 진력변환장치로 크게 나눌 수 있다. 또한 전력변환부는 승압용 컨버터부와 DC전력을 AC로 변환하는 인버터부로 구성된다. 종래 인버터의 주회로 방식은 저주파 트랜스나 고주파 트랜스를 사용하는 방식이 채러되었으나, 최근 이러한 방식에 비해 소형 경량화가 기대되는 트랜스리스 방식이 많이 연구되고 있다. 본 논문의 승압부는 2상 부스트 컨버터를 이용하여 입력 전류와 출력 전압의 리플을 줄여, 각 전력 소자의 전압 스트레스를 줄이고, 입력 리액터를 소형화한다. 그리고, 인버터 부의 출력 고조파 성분을 저감하기 위해 정현파 PWM에서 얻어진 스위칭 시간을 기본값으로 하여 푸리에 급수로 유도한 PWM 스위칭 시간을 채택하였고, PSpice를 이용하여 변환기의 동작을 시뮬레이션하여 그 유효성을 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.238-243
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• 2003

The solar cells should be operated at the maximum power point because its output characteristics are greatly fluctuated on the variation of insolation, temperature and load. The output power of solar cell is DC, therefore it is necessary to install an inverter among electric power converts. The inverter have to supply a sinusoidal current and voltage to the load and the interactive utility line. In the paper, the proposes a photovoltaic system designed with a step up chopper and single phase PWM voltage source inverter. Synchronous signal and control signal was processed by microprocessor for stable modulation. The step up chopper operates in continuous mode by adjusting the duty ratio so that the photovoltaic system tracks the maximum power point of solar cell without any influence on the variation of insolation and temperature because solar cell has typical dropping character. The single phase PWM voltage source inverter consists of complex type of electric power converter to compensate for the defect, that is, solar cell cannot be developed continuously by connecting with the source of electric power, from 10 to $20\%$. The single phase PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. The inverter supplies an ac power with high factor and low level of harmonics to the load and the utility power system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.648-653
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• 1998

The conventional three-phase rectifier with bulky LC output filter has been widely used in the industry because of its distinctive advantages over the active power factor correction rectifier such as simple circuit, high reliability, and low cost. Over than 0.9 power factor can be achieved, which is acceptable in most of industry applications. This rectifier, however, is not easy to use for high power density applications since the LC filter is bulky and heavy. To solve this problem, a new simple rectifier is presented in this paper. By eliminating the bulky LC filter from the conventional diode rectifier without losing most of the advantages of the conventional rectifier, very high power density power conversion with high power factor can be achieved. Operation principle and design considerations are illustrated and verified by Pspice simulation and experimental results from a prototype of 3.3 kW rectifier followed by 100KHz zero voltage switching full bridge PWM converter

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 Proceedings of 6th International Joint Symposium on Microeletronics and Packaging
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• pp.57-65
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• 2001

Economical consumption of energy, longer life of lamps, higher lighting comfort and new aesthetic of illumination is subject of numerous research and development works. The halogen lamps are an example of positive solution some of above mentioned problems. The electronic transformers are more frequent used for their supply. In comparison with conventional transformers they have less weight, less volume and 60% less power tosses. Their advantages are particular visible, when the hybrid technique is applied. The paper presents the results of engineering research and development works carried out ill Private Institute of Electronic Engineering, in R. & D. Center for Hybrid Microelectronics and Resistors and in Technical School of Communications in Krakow, in the field of the design and exploitation tests of hybrid converters 220V AC /12V DC (electronic transformers) and electronic ballasts destined for the supply of halogen lamps 20W to 150W and fluorescent lamps respectively. To perform the converters, thick film technology and surface mount technology were used. For the protection of converter electronic circuit the thick film temperature sensor and transistors were applied. Moreover the paper presents the base application circuits of elaborated converters, their technical parameters and exploitation results. The development perspectives of hybrid domain of hybrid circuits are also discussed.