• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2254-2261
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• 2018

This paper analyzes stability of current control in respect of four cases of battery energy storage system (BESS) in a stand-alone microgrid. The stand-alone microgrid is composed of BESS, diesel generator and controllable loads, where all of them have a rated power of 50kW. The four cases are considered as following: 1) BESS with a stiff grid 2) BESS with the diesel generator 3) BESS with passive damping + diesel generator 4) BESS with active damping + diesel generator, and their stabilities are analyzed in the frequency domain and discrete time domain. The comparative analysis for four cases are verified through simulation and experiments through demonstration site of the stand-alone microgrid, where the DC link is connected to a 115kW battery bank composed of 48 lead-acid batteries (400AH/12V). Experimental results show a good agreement with the analysis.

• 전기학회논문지
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• 제58권3호
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• pp.523-530
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• 2009

This paper presents a study on a small scale single-phase UPFC preliminary researches on power quality compensating schemes of electrical railway. As the UPFC is very complicated power-electronic system consisting of grid-connected transformers, four single phase inverters interconnected with dc-link capacitors and various electrical apparatuses, multiple controllers and control algorithms are needed, and entire UPFC has been modelled in the form of block diagrams and simulated by using Simulink. The main purpose of the compensating system is to manage reactive and active powers with the four single phase inverters, so, the control effort has been focused on the power flow control and has been realized through the hysteresis current control of the single phase inverters. And transport-delayed PLL with additional delay-time compensating term has been used to synchronize a grid voltage and the simulation results have shown that the compensating term could improve PLL performance under some frequency variation of the voltage.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.959-962
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• 2004

A strategy for a torque ripple reduction drive of single-phase SRM with high power factor is proposed. The drive for switched reluctance motor (SRM) is presented to achieve sinusoidal, near unity power factor input current with low torque ripple. The proposed SRM drive has no additional active switch. And a single-stage approach, which combines a DC link capacitor used as do source and a drive used for driving the motor into one power stage, has a simple structure and low cost. The characteristics and validity of the proposed circuit is discussed in depth through the experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.670-672
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• 2004

In this paper, single phase boost converter with low current harmonic components and high power factor are proposed. A single-phase half-bridge rectifier based on a neutral point switch clamped scheme is proposed to draw a nearly unity power factor and regulate the DC link voltage. Three power switches are employed in the proposed rectifier. This rectifier is controlled to generate a bipolar or unipolar PWM voltage waveform on the AC side. The proposed converter is implemented by a digital signal processor.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.308-311
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• 2004

A novel single-stage power factor corrected (PFC) drive for switched reluctance motor (SRM) is presented to achieve sinusoidal, near unity power factor input current. The proposed PFC SRM drive has no additional active switch. And a single-stage approach, which combines a DC link capacitor used as do source and a drive used for driving the motor into one power stage, has a simple structure and low cost. The characteristics and validity of the proposed circuit will be discussed in depth through the experimental results.

• Journal of Power Electronics
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• 제9권3호
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• pp.418-429
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• 2009

In this paper an optimal damped input filter is designed based on a Genetic Algorithm (GA) for an electrolytic capacitor-less AC-AC converter. Sufficient passive damping and minimum losses in passive damping elements, minimization of the filter output impedance at the filter cut-off frequency, minimization of the DC-link voltage and input current fluctuations, and minimization of the filter costs are the main objectives in the multi-objective optimization of the input filter. The proposed filter has been validated experimentally using an induction motor drive system employing an electrolytic capacitor-less AC-AC converter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1110-1112
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• 2001

This paper presents a high frequency electronic ballast with high efficiency and high power factor. The proposed ballast have driven by the half bridge inverter which is linked diode rectifier without DC link capacitor. Minimized elements of circuit configurations can make the efficiency of the ballast increase. High input power factor which is up to 0.96 can be achieved and the crest factor of lamp current waveforms is controlled with below 1.75 by using a novel control scheme which has PFM and PWM methods simultaneously. In this paper, the circuit configurations of the proposed ballast and the control schemes are described. The usefulness of the proposed ballast is confirmed with the simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1085-1087
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• 2001

This paper deals with single-phase unified power quality conditioner, which aims at the integration of series-active and shunt-active tilter. The series filter is used to compensate for the voltage distortions and the shunt filter is used to provide reactive power and counteract the harmonic current injected by the load. Also, the voltage of the DC link capacitor is controlled to a desired value by the shunt active filter. In order to verify the performance of the proposed conditioner, computer simulations using MATLAB/SIMULINK were demonstrated. The results confirm that the proposed conditioner shows excellent performance to eliminate the harmonics and voltage flickers generated at the singe-phase nonlinear load.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.187-188
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• 2014

본 논문에서는 3-레벨 NPC(Neutral Point Clamped) 인버터에서 상단 커패시터 전압과 하단 커패시터의 전압의 불균형 시 나타나는 출력 상전류 왜곡에 대한 보상기법에 대하여 제안한다. 스위칭 기법은 SVPWM(Space Vector Pulse Width Modulation)을 사용하였고 상단 커패시터 전압과 하단 커패시터 전압의 불균형이 DC-Link 전압의 0% 15% 35%일 때의 보상 전과 보상 후를 비교 분석 하여 시뮬레이션으로 출력 상전류 보상기법을 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 추계학술대회 논문집
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• pp.213-214
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• 2012

속도 범위가 넓은 고속 PMSM의 정현파 구동용 인버터에서 전동기 전류 리플과 인버터 스위칭 손실을 저감시키는 방법으로서, 중저속에서 직류 링크전압을 감소시키는 방법을 제안한다. 직류 링크전압 조절용 컨버터를 이용하며, 직류 링크 전압과 전동기 속도 사이의 관계를 설정하고 이를 제어 알고리듬에 반영한다. 제안된 기법에 의한 전류 리플 저감효과를 시뮬레이션으로 확인한다.