• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.100-102
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• 2007

In this paper, a modified multi-level convert for low cost high speed switched reluctance (SR) drive is proposed The proposed multi-level converter has reduced number of power switches and diodes than that of a conventional asymmetric converter for SRM, and lower voltage rating of the dump capacitor comparing with energy efficient c-dump converter. It can supply five operating modes that is boosted, DC-link, zero, negative bias and negative boosted voltage. The proposed multi-level converter has fast excitation and demagnetization modes of phase current, so dynamic response can be achieved. The proposed multi-level converter is verified by computer simulation and experimental results.

• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.1009-1012
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• 1995

This paper presents an example of the development of motor drives for machine tools. Machine tools need motor drives with high control precision and performance. We developed a motor drive system that meets these requirements. The converter, the one component of drive system, adopts modular structure and high DC-link voltage. The drive which consists rest part of drive system is developed based on TMS320C32 DSP and state-of-the-art circuit technology. In this paper each developed parts are described in terms of its structure, specification and features.

• 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.

• 조명전기설비학회논문지
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• 제26권12호
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• pp.62-67
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• 2012

In this paper general purpose voltage source inverter drives are equipped with an under-voltage protection mechanism, causing the system to shut down within a few milliseconds after a power interruption in the main input sources. When a power interruption occurs finish, if the system is a large inertia restarting the load a long time is required. This paper suggests modifications in the control algorithm in order to improve the sag ride-through performance of ac inverter. The new proposed strategy recommends maintaining the DC-link voltage constant at the nominal value during a sag control algorithm, experimental results are presented.

• 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.

• 전력전자학회논문지
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• 제10권5호
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• pp.494-500
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• 2005

본 논문에서는 플라이휠에너지를 이용한 다이나믹 UPS 시스템에서 유도기를 이용하여 플라이휠의 에너지를 저장 및 재생하는 시스템 제어 기법을 제시하였다. 유도발전기의 슬립주파수 제어와 벡터제어 기법의 특성을 비교하고, 또한 벡터제어 기법을 사용 시 전동 모드에서 발전 모드로의 전환할 때 직류링크 커패시터 전압의 과도 특성을 개선하는 기법을 개발하였다. 32비트 DSP를 사용한 실험을 통하여 이 기법의 성능을 확인하였다.

• 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.