• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1124-1136
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• 2017

Direct Power Control technique has become popular in the grid connected Voltage Source Converter (VSC) applications due to its simplicity, direct voltage vector selection and improved dynamic performance. In this paper, a direct method to determine the effect of voltage vector on the instantaneous active and reactive power variations is developed. An alternative Look Up Table is proposed which minimizes the commutations in the converter and results in minimum reactive power variation. The application of suggested table is established for Shunt Active Power Filter (SAPF) application. The Predictive Direct Power Control method, which minimizes apparent power variation, is further investigated to reduce commutations in converters. Both the methods are validated using 2 kVA laboratory prototype of Shunt Active Power Filters (SAPF).

• 조명전기설비학회논문지
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• 제28권1호
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• pp.36-44
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• 2014

The conventional central photo voltaic inverters have several problems. First, shadow problem in each solar panel, and high DC voltage problem from each panel because of concentration to one central inverter. Therefore, module integrated inverter is proposed to solve these problems. The inverter should be small and cost effective. The cost and size in the inverter depend on the inductor. So the switching frequency should be increased to reduce the inductor and total size, but there is a problem in efficiency because of the losses in turn-on and turn-off. In the paper, the critical conduction mode(CRM) switching method is adopted to reduce the switching loss and interleaving method is proposed to increase the efficiency in Flyback converter. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype system rated at 200W.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.276-277
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• 2010

This paper describes the control of a utility-connected doublefed induction machine (DFIM) for wind power generation systems (WPGS). Real and reactive powers (PQ) at the stator side of DFIM are strictly controlled to supply the power to the grid without any problems. In this paper the control is realized using Fuzzy PI controller based on the stator-flux orientation control.

• Journal of Power Electronics
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• 제17권4호
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• pp.1071-1087
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• 2017

This paper introduces a DC/AC converter, which can be connected in parallel with a diode rectifier for regenerative applications. The DC/AC converter is supposed to transmit regenerative energy to the power grid when a motor is braking. Isolation transformers are not needed in the topology, which can reduce the size and cost. An analysis of the zero-order current existing in the system is carried out. In addition, algorithms to minimize the zero-order current, control the power factor and keep the DC bus voltage stable are discussed. A 55kW industrial prototype is built to verify the proposed analysis and control strategies.

• Journal of Power Electronics
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• 제18권4호
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• pp.997-1006
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• 2018

This paper proposes a transformerless photovoltaic (PV) power converter system based on the DC/AC boost inverter, which can solve the leakage current and second-order ripple power issues in single-phase grid-connected PV inverters. In the proposed topology, the leakage current can be decreased remarkably since most of the common-mode currents flow through the output capacitor, by-passing parasitic capacitors, and grounding resistors. In addition, the inherent ripple power component in the single-phase grid inverter can be suppressed without adding any extra components. Therefore, bulky electrolytic capacitors can be replaced by small film capacitors. The effectiveness of the proposed topology has been verified by simulation and experimental results for a 1-kW PV PCS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.317-319
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• 2005

In this paper, control algorithm for torque ripple compensation in DFIG wind power generation system is proposed. A simple PI controller is designed for the negative sequence voltage cancellation using negative sequence currents in the grid-side converter. As a result, the stator voltage contains only the positive sequence components and the torque pulsation of the generator is effectively compensated. Propose algorithm is confirmed with PSCAD simulation model.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.677-681
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• 2005

This Paper presents a 6 pulse shift operation control mode of current-source-inverter to make improvement of efficiency and to reduce the frequency of inverter switching for photovoltaic generation system using PWM current-source-inverter. This system is connected solar cell energy directly without using a storage cell. The proposed circuit can maintain maximum voltage of photovoltaic generation of take advantage of six Buck-Boost converter and a full-bridge inverter determines the polarity of AC output. That is controlled by using digital signal processor TMS320F2812 for operation about a 6 pulse shift operation control of current-source-inverter, and it is verified through the experimental results.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.408-421
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• 2008

In this paper, the parallel operation for a FC generation system is introduced and designed in order to increase the capacity for the distributed generation of a proton exchange membrane fuel cell (PEMFC) system. The equipment is the type that is used by parallel operated PEMFC generation systems which have two PEMFC systems, two dc/dc boost converters with shared dc link, and a grid-connected dc/ac inverter for embedded generation. The system requirement for the purpose of parallel operated generation using PEMFC system is also described. Aspects related to the mechanical (MBOP) and electrical (EBOP) component, size, and system complexity of the distributed generation system, it is explained in order to design an optimal distributed generation system using PEMFC. The optimal controller design for the parallel operation of the converter is suggested and informative simulations and experimental results are provided.

• 전기전자학회논문지
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• 제23권3호
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• pp.1003-1014
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• 2019

본 논문에서는 PV 시스템에서 사용되는 회로들을 쉽게 해석할 수 있도록 모델링하였다. 시뮬레이션 툴은 직관적인 전기회로 시뮬레이션이 가능한 PSPICE를 이용하였다. 모델링한 라이브러리를 이용하여 태양전지의 사용에서 간과하기 쉬운 온도와 공간방사의 영향에 대해서도 시뮬레이션을 수행하였다. 이와 더불어 태양광 발전 시스템의 완전한 동작을 위해 DC-DC 벅-부스트 컨버터와 MPPT 제어 시스템에 대한 완전한 동작 시스템에 대해 모델링하고 시뮬레이션을 수행하여 양호한 동작을 확인할 수 있었다. 또한 시뮬레이션의 동작을 입증하기 위하여 시뮬레이션에서와 동일한 조건의 실제 시스템을 구성하여 실험을 수행 하였으며 실험의 결과와 시뮬레이션의 결과가 동일한 동작을 수행하는 것을 확인할 수 있었다. 또한, 단상 3[kW] 계통연계형 태양광 전력변환기를 제안하였다.

• 전력전자학회논문지
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• 제11권3호
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• pp.193-200
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• 2006

본 논문에서는 효율을 개선하고 인버터 스위칭 주파수를 줄이기 위하여 벅-부스트 형식을 기반의 PWM 전류형 인버터를 내장한 6-pulse-shift 컨버터 구조를 제안한다. 이는 에너지 저장장치 없이 태양광 시스템과 전력계통 사이를 연계하는 시스템으로 사용할 수 있다. 제안된 회로는 초퍼로 동작하는 6개의 전류형 벅-부스트 컨버터와 교류 출력의 극성을 결정하는 한 개의 전파 브리지 인버터로 구성된다. 따라서 제안된 인버터는 스위칭 손실을 줄이고 단위 역률운전을 구현하는 장점을 갖는다. 본 논문에서 이론적인 배경을 논하고 TMS320F2812를 사용하여 구현된 인버터 시작품에 대한 입출력 특성을 실험적으로 입증하였다.