• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.177-181
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• 2004

In this paper design of speed controller for AC servo system by rapid design system(RG-01D) using DSP of Realgain company is introduced. 'AC Servo-Designer' system, including CEMTool/SIMTool S/W, RG-DSPIO board, AC servo driver and AUTOTool program, is used in this research. Because 'AC Servo-Designer' system can use SIMTool blocks to design and implement various controller in short time, speed controller for AC servo system is easily designed and implemented according to control objectives.

• 한국산학기술학회논문지
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• 제6권6호
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• pp.453-456
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• 2005

본 논문에서는 리얼게인사의 DSP를 사용하는 고속설계시스템에 의한 AC 서보 시스템의 속도관측기 및 속도제어기의 설계에 대하여 소개한다. CEMTool/SIMTool 소프트웨어 프로그램과 RG-DSPIO 제어보드, AC 서보 드라이버와 AUTOTool 프로그램으로 구성되어 있는 "AC Servo-Designer" 시스템이 본 연구에서 사용되었다. "AC Servo-Designer" 시스템은 SIMTool 블록들을 사용함으로써 짧은 시간동안에 다양한 형태의 제어기를 설계 및 구현할 수 있도록 해 주는 장점이 있기 때문에 AC 서보 시스템의 속도 관측기 및 속도제어기를 제어 목적에 따라서 쉽게 설계하고 구현할 수 있다.

• Journal of Power Electronics
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• 제12권1호
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• pp.157-163
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• 2012

Internet Data Centers (IDCs), which are essential facilities in the modern IT industry, typically have scores of MW of concentrated electric loads. The provision of an Uninterruptible Power Supply (UPS) is necessary for the power feed system of IDCs owing to the need for stable power. Thus, conventional IDC AC power feed systems have three cascaded power conversion stages, (AC-DC), (DC-AC), and (AC-DC), resulting in a very low conversion efficiency. In comparison, DC power feed systems require only a single power conversion stage (AC-DC) to supply AC main power to DC server loads, resulting in comparatively high conversion efficiency and reliability [4-11]. This paper compares the efficiencies of a 220V AC power feed system with those of a 300V DC power feed system under equal load conditions, as established by the Mok-Dong IDC of Korea Telecom Co. Ltd. (KT). Experimental results show that the total operation efficiency of the 300V DC power feed system is approximately 15% higher than that of the 220V AC power feed system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.184-186
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• 2003

In this paper, speed and Position control of AC servo system using SIMTool of Realgain company is introduced. "AC Servo-Designer"system, including CEMTool/SIMTool S/W, RG-DSPIO board, AC servo driver and AUTOTool program, is used in this research. "AC Servo-Designer"system can use SIMTool blocks to Because design and implement various controller in short time, speed and position controller of AC servo system are easily designer and implemented according to control objectives.

• Journal of Electrochemical Science and Technology
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• 제2권3호
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• pp.152-156
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• 2011

A hybrid supercapacitor is fabricated using a composite material from $LiMn_2O_4$ (LMO) and activated carbon (AC) as the positive electrode and AC as the negative electrode to form the (LMO + AC)/AC system. Volume ratio (positive : negative) of electrodes is controlled to investigate of the power and energy balance. The (LMO + AC)/AC system shows better performances than the LMO/AC system. Especially, electrochemical impedance spectra, rate charge.discharge and cycle performance testing show that the (LMO + AC)/AC system have an outstanding electrochemical performance at volume ratios of (LMO + AC)/AC = 1 : 1.7 and 1 : 2. Electric double layer capacitor (EDLC) capacitance between AC of the positive electrode and AC of the negative electrode improves power density without loss of capacitance. Stable capacitance is achieved by lowering the positive electrode resistance and balancing the energy and power densities between the positive and negative electrodes by the addition of AC to the positive electrode at high current density.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.430-434
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• 2002

최근 전력품질 개선을 위한 Custom Power 기기 가운데 PWM AC-AC 컨버터를 이용한 전압 안정화 기기에 대한 연구가 활발하다. 본 논문에서는 PWM Buck-Boost AC-AC컨버터를 이용한 전압 전압안정학기가 제안되고, 회로 DQ 변환기법을 사용하여 그 정상상태 특성을 해석하고 전압이득과 역률에 대한 해석적인 식을 밝힌다. 그럼으로써 각종 회로 파라미터가 전압이득과 역률에 미치는 영향을 분석하여 설계시 기준이 되도록 하였다. 실험을 통하여 해석된 내용이 서로 일치함을 보인다.

• Journal of Power Electronics
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• 제3권4호
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• pp.249-258
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• 2003

This paper presents a high-efficient and cost effective three-phase AC/DC-DC/AC power conversion system with a single two-switch type active Auxiliary Resonant DC Link (ARDCL) snubber circuit, which can minimize the total power dissipation. The active ARDCL snubber circuit is proposed in this paper and its unique features are described. Its operation principle in steady-state is discussed for the three phase AC/DC-DC/AC converter, which is composed of PWM rectifier as power factor correction (PFC) converter, sinewave PWM inverter. In the presented power converter system not only three-phase AC/DC PWM rectifier but also three-phase DC/AC inverter can achieve the stable ZVS commutation for all the power semiconductor devices. It is proved that the proposed three-phase AC/DC-DC/AC converter system is more effective and acceptable than the previous from the cost viewpoint and high efficient consideration. In addition, the proposed two-switch type active auxiliary ARDCL snubber circuit can reduce the peak value of the resonant inductor injection current in order to maximize total system actual efficiency by using the improved DSP based control scheme. Moreover the proposed active auxiliary two-switch ARDCL snubber circuit has the merit so that there is no need to use any sensing devices to detect the voltage and current in the ARDCL sunbber circuit for realizing soft-switching operation. This three-phase AC/DC-DC/AC converter system developed for UPS can achieve the 1.8% higher efficiency and 20dB lower conduction noise than those of the conventional three-phase hard-switching PWM AC/DC-DC/AC converter system. It is proved that actual efficiency of the proposed three-phase AC/DC-DC/AC converter system operating under a condition of soft switching is 88.7% under 10kw output power.

• 조명전기설비학회논문지
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• 제18권1호
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• pp.67-72
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• 2004

AC 서보 시스템은 고 정밀도가 요구되는 공장 자동화 시스템(FA)에 적용 되어왔고 시스템의 성능에 직접적인 관계가 있다. 최근 전력용 소자와 AC 서보 제어를 위한 여러 기능이 내장된 DSP의 발전은 AC서보 기술에 큰 전환점을 주게되었다. 본 연구에서는 가장 최근 출시되었고, 150MIPS의 빠른 연산 속도와 AC서보 시스템을 위한 여러 회로들이 내장된 DSP인 TMX320F2812를 이용하여 3상 PMSM 기반의 AC서보 시스템을 구현하였다. 또한 SVPWM과 디지털 PI제어기를 적용하여 모터의 효율 및 제어 특성을 향상시키었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.749-753
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• 2003

본 논문에서는 Custom Power의 전력품질의 향상을 위하여 PWM Buck-Boost AC-AC 컨버터를 사용, 항상 일정한 출력전압을 얻는 시스템을 보이고 제어를 위한 동적 모델링 및 제어기 설계의 일례를 보였다. 그 결과, 시스템 상태방정식을 유도하였고 전달함수를 구였으며 일정한 동작점 하에서 출력전압을 기준전압으로 regulation 제어하기 위한 제어기에 대하여 다루었다. 끝으로, 실험을 통하여 제안된 모델링과 시스템 설계가 타당함을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.109-117
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• 2015

This paper proposes the comparison results of various optimal power flow algorithms (OPF) to calculate the locational marginal prices (LMP) of the unreduced full scale Korean transmission system. Five different types of optimal power flow models are employed: Full AC OPF, Cubic AC OPF, Quadratic AC OPF, Linear AC OPF and DC OPF. As the results, full AC OPF and cubic AC OPF model provides LMP calculation results very similar to each other while the calculation time of cubic AC OPF model is faster than that of the Full AC OPF. Other simplified OPF models, quadratic AC OPF, linear AC OPF and DC OPF offer erroneous results even though the calculation times are much faster than the Full AC OPF and the Cubic AC OPF. Given the condition that the OPF models sometimes fail to find the optimal solution due to the severe complexity of the Korean transmission power system, the Full AC OPF should be used as the primary OPF model while the Cubic AC OPF can be a promising backup OPF model for the LMP calculations and/or real-time operation.