• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1209-1211
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• 2001

Generally, the current controller is located inner the whole controller, so the characteristic of the current controller is important in controlling performance of the upper controller. A current control loop in motor control is designed so that it is 10 times faster than the speed control loop of the upper controller. Thus, the current controller with complex control algorithm is not proper. In this paper, the improved current controller using a conventional digital PI controller and feedforward controller for the brushless BC motor is designed.

• 한국시뮬레이션학회논문지
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• 제19권3호
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• pp.71-79
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• 2010

디지털 계측제어계통을 발전소에 적용하기 전에 시험 및 검증하기 위하여 500MW급 표준화력발전소 시뮬레이터 모델을 개발하고 터빈 제어시스템과 연계하였다. 선택된 디지털 계측제어계통의 성능시험 시, 해당되는 시뮬레이터 모델은 조정할 수 없는 발전소 디지털 계측제어계통과 교체된다. 시뮬레이터 모델 및 제어시스템의 입출력은 연계장치에 있는 LabView 프로그램을 사용하여 연결되었다. 본 논문에서는 시뮬레이터 모델 및 디지털 계측제어계통을 연계하는 방법론에 대하여 기술하고, 정상운전, 과도상태 및 고장인가 시 수행된 검증시험 결과를 제시하였다. 시뮬레이터 모델을 사용한 디지털 계측제어계통의 종합검증을 통하여 시뮬레이터가 디지털 제어시스템을 발전소에 적용하기 위한 시험장치로 사용될 수 있는 방법론을 개발하였다.

• 조명전기설비학회논문지
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• 제22권11호
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• pp.30-35
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• 2008

An analog type turbine control system in a nuclear power plant in Korea was replaced by a digital type control system successfully. The turbine simulator was used to verify and validate the perfection of newly developed digital control system prior to its actual installation. In this paper, the newly developed turbine speed control system, ie. governor will be introduced together with how to simulate entire control loop. After that, we will compare the comparison of simulation result in laboratory with pre startup simulation result. Eventually the performance of actual operation result was testified.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.129-130
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• 2010

For the high power demand and N+1 redundancy, this paper presents the digital load share (LS) controller design and the implementation of paralleled phase-shifted full-bridge converters (PSFBC) used in distributed power systems. By adopting the digital control strategy, separately used ICs for PSFBC and LS control functions in analog systems can be merged into a cost-effective digital controller. To compensate and stabilize both PSFBC and LS loops with the direct digital design approaches, small-signal model of the system is derived in discrete-time domain. The steady-state and dynamic load sharing performances are also investigated. Experimental results from two 1.2 kW paralleled PSFBC modules are shown to verify the proposed work.

• 전력전자학회논문지
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• 제25권1호
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• pp.54-60
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• 2020

A digital current control scheme using virtual d-q transformation for a boost single-phase power factor correction (PFC) converter is proposed. The use of virtual d-q transformation in single-phase power converters is known to improve current control performance. However, the conventional virtual d-q transformation-based digital current control scheme cannot be directly applied to the boost single-phase PFC converter because the current and average voltage waveforms of the inductor used in the converter are not sinusoidal. To cope with this problem, this study proposes a virtual sinusoidal signal generation method that converts the current and average voltage waveform of the inductor into a sinusoidal waveform synchronized with the grid. Simulation and experimental results are provided to show that the virtual d-q transformation-based digital current control is successfully applied to the boost single-phase PFC converter with the aid of the proposed virtual sinusoidal signal generation method.

• 전력전자학회논문지
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• 제9권3호
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• pp.275-284
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• 2004

본 논문은 동적전압보상기(DVR)의 제어를 위한 우수한 성능의 디지털제어기를 제시하고 제어이득(Control Gain)의 설정에 관하여 논한다. DVR계통의 전력회로를 분석하여 DVR의 운전한계를 찾고 그에 따른 제어목표 및 제어기 구조를 제시한다. 디지털 제어기는 인버터의 PWM 스위칭과 함께 제어시스템의 시간지연을 야기한다. 이러한 시간 지연은 제어시스템의 전달함수를 1차수 높게 하여 제어시스템을 더한층 복잡하고 불안정하게 한다. 본 논문은 제어기의 시간지연을 고려하여 제안된 제어기의 이득을 설정하는 방법을 제시하고 인버터의 스위칭 주파수와 관련하여 출력측 필터요소의 설계지침을 제시한다. 제안된 설계방법에 의하여 전디지털화(Full Digital Control) 된 DVR 시스템을 제작하여 이론을 검증한다.

• Journal of Power Electronics
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• 제18권1호
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• pp.160-170
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• 2018

For high power photovoltaic (PV) grid-connected converters, high order filters such as multi-tuned filters and Traps+RC filters with outstanding filtering performance have been widely researched. In this paper, the optimization of a multi-tuned filter with a low damping resistance and research on its corresponding control scheme have been combined to improve the performance of the proposed filter. Based on the characteristics of the switching harmonics produced by PWM, the proposed filter is optimized to further improve its filtering performance. When compared with the more common Traps+RC filter, the advantages of the proposed filter with low damping resistances in attenuating the major switching harmonics have been demonstrated. In addition, a simpler topology and reduced power loss can be achieved. On the other hand, to make the implementation of the proposed filter possible, on the base of the unique frequency response characteristic of the proposed filter, a digital single-loop control scheme has been proposed. This scheme is a simple and effective means to suppress the resonance peak caused by a lack of damping. Therefore, a smaller volume, better efficiency of the proposed filter, and easy implementation of the corresponding control scheme can be realized. Finally, the superiority of the proposed filter topology and control scheme is verified in experiments.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.1011-1015
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• 2005

Fully digital controlled 20-bit magnet power supplies have been developed and successfully tested for closed orbit correction of PLS(Pohang Light Source). The new digital power supply has used fiber optics for 25kHz switching of IGBT drivers, and implemented DSP, ADC, Interlock, DCCT cards in a compact 3U-sized 19" chassis. Input/Output low-pass filters suppress harmonics of 60Hz line frequency and switching frequency noise effectively. Overall performance of the power supplies have been demonstrated as +/- 2ppm short-term stability(<1 min), and +/- 10ppm long-term stability(<36 hours). All the existing 12-bit 70 power supplies for vertical correction magnets will be replaced with new digital power supplies during 2005 summer shutdown period. In this paper, we will describe the hardware structure and control method of the digital power supply and the experimental results will be shown.

• 시스템엔지니어링학술지
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• 제5권1호
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• pp.33-41
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• 2009

The analog or partly digital typed interface of main control room in nuclear power plant (NPP) is gradually being replaced to the totally digitalized interface suitable for the digital environment. SKN 3,4 Nuclear Power Plant is currently developed in such a way to employ advanced displays and controls such as computerized procedure system(CPS), large display panel(LDP), and Soft control. According to the developed design process, the main control room (MCR) of the SKN3,4 was aesthetically designed based on a design concept of the health and sustainability and technically evaluated with human factors guidelines, which somehow lack of the confidence on the evaluation for the rapidly changing digital environment. The suitable review guideline for the digitalized interface and the environment was developed such as the guideline for CPS with information displays on VDU. For the guideline development, tremendous guidelines and technical papers related to evaluation issues of digital environment has been collected, analyzed and transformed to electric database forms and then built on database management system, called Design Review Supporting System to retrieve the appropriate issues for the practical usage of evaluators-in-field.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.575-580
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• 1998

A power meter is an instrument for measuring in watts the power flowing in a electric equipment. Since the value which a conventional power meter measures is analog, the power meter is hard to determine a phase difference between the voltage and current for a inductive load. The phase difference causes a loss of electric power and a increase of power-line load. In this paper, we propose a digital power meter using TI's DSP(Digital Singnal Processor) TMS320C5x, which is employed to calculate the phase difference and more accurate power consumption.