• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.109-112
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• 1996

In this paper, we composed utility interactive photovoltaic generation system of current source inverter, and controlled that low harmonic and high power factor are hold by supposing control and compensation method which is concerned with synchronous signal distortion and modulation delay. And we put parallel resonant circuit into dc link, so, magnitude of direct reactance was reduce by restraining direct current pulsation which had accumulation of pulsating power in alternating electrolytic condenser. Also we controlled that modulation factor is operated around maximum output of solar cell.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.659-662
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• 1999

As utility pollution take a growing interest, ac/dc converter optimizing utility condition has been vigorously studied in decades. In this paper three phase DCM converter is analyzed and equations for average input currents are presented. Also relationships of voltage gain & duty according to angular velocity are presented and variable frequency controller is implemented using reset integrator which is designed in detail. In result power factor and THD characteristics of 3-stage and 4-stage operation ae compared respectively.

• 전력전자학회논문지
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• 제7권2호
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• pp.171-177
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• 2002

계통연계형 태양광 발전시스템은 계절별 전력수요의 변동이 많은 경우에 첨두전력 삭감의 한 방안으로 고려된다. 본 시스템의 발전효율을 증가시킬 수 있는 방법으로는 근본적으로 태양전지 자체의 변환효율을 증가시키는 방법과 제어관점에서 일사량과 태양전지 표면온도에 따라 시시각각 변하는 태양전지의 최대출력 점에 시스템의 동작점을 추종하게 하는 최대 전력점추적 (Maximum Power point Tracking, 이하 MPPT) 기법을 들 수 있고 발전 효율을 높이기 위하여 자주 사용되어 왔다. 초기 투자비용을 줄이기 위해 후에 등장한 직류초퍼를 사용하지 않고 MPPT 기능을 구현하는 태양광 발전시스템의 경우에 MPPT 알고리즘은 기존의 방법들을 사용하였고 직류초퍼를 사용하지 않은 태양광발전시스템에 적합한 MPPT 알고리즘의 연구는 없었다. 따라서 직류초퍼를 사용하지 않은 태양광 발전시스템에 적합한 MPPT 알고리즘의 연구가 요구되며 본 논문에서는 초퍼 없는 계통연계형 태양광발전 시스템을 대상으로 기존 MPPT 알고리즘의 문제점을 밝히고 이를 해결할 수 있는 새로운 MPPT 알고리즘을 연구하였다.

• 전기학회논문지
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• 제66권7호
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• pp.1032-1038
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• 2017

Recently, regulation on carbon emissions has been strengthened according to the new climate change convention (COP21) held in Paris, and then Korea has decided to reduce CO2 emissions by 37% until 2030. As one of countermeasures, the government has energetically performed demonstration projects of island micro-grid including solar power, wind power and energy storage system. However, in order to smoothly introduce island micro-grid, it is a critical issue to carry out the economic evaluation for power utility aspect and independent power producer aspect. Therefore, this paper proposes economic evaluation algorithms of island micro-grid which are based on the present worth method, considering cost and benefit factors in the aspect of both sides. Firstly, in case of power utility this paper proposes algorithm to estimate a period of return on investment according to the introduction capacity of distributed generators replacing diesel generator. And also, in case of independent power producer, this paper proposes evaluation algorithm to estimate weighting factor of SMP and benefit rate based on break-even point related with cost and benefit. From a case study result on real island micro-grid model, it is confirmed that proposed algorithms are useful and practical for the economic evaluation of island micro-grid.

• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.90-95
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• 2015

This paper describes IEC 61727 standard of Photovoltaic (PV) systems -Characteristics of the utility interface. IEC 61727 standard tests include utility compatibility and personnel safety and equipment protection of PV inverter performance functions. Especially utility compatibility part includes test items of 1) voltage, current and frequency, 2) normal voltage operating range, 3) flicker, 4) DC injection, 5) normal frequency operating range, 6) harmonics and 7) waveform distortion, 8) power factor of PV inverter. Also personnel safety and equipment protection part includes test items 1)loss of utility voltage, 2)over/under voltage and frequency, 3)Islanding protection, 4)response to utility recovery, 5)earthing, 6)short circuit protection, 7)Isolation and switching of PV inverter. In this paper, each item of IEC 61727 standard test is studied and analyzed and finally full tested by PV inverter performance function.

• 전기학회논문지
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• 제67권3호
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• pp.479-484
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• 2018

This paper describes domestic technical standard of Photovoltaic(PV) PCS(Power Conditioning Systems)-Characteristics of the utility interface. This standard tests utility compatibility and personnel safety and equipment protection of PV inverter performance functions. Especially utility compatibility part includes test items of 1)voltage, current and frequency, 2)normal voltage operating range, 3)DC injection, 4)normal frequency operating range, 5)harmonics and 6)waveform distortion, 7)power factor of PV inverter. Therefore in this paper each test item of domestic technical standard is studied and analyzed and finally full tested by PV inverter performance function.

• 에너지공학
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• 제8권1호
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• pp.76-84
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• 1999

The demand of Small Self-generating System (SSS) including Small Cogeneration System (SCS) is constantly increasing with the need of electricity and/or thermal in office, hospital, hotel, and small factory, etc. It is especially recommended to operate SCS in the heat-following mode to maximize the efficiency of generator. In case of the heat-following mode SCS has got to be connected to distribution system so as to send surplus power to the utility or receive the short power from utility. But the interconnection of SSS with distribution system causes a few problems such as the bad power quality, and low security. If SSS is not promptly disconnected after faults occur (Islanding of SSS), it can not only damage equipment of utility and adjacent customers but also endanger life of human due to overvoltage or overcurrent. In this paper it has been deeply discussed if interconnection of engine self-generator/control system satisfies the protective requirement for SSS or not. 500 kW engine generator running in the Jodo island has been used to perform the analysis of interconnection.

• 전력전자학회논문지
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• 제8권2호
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• pp.199-210
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• 2003

본 논문에서는 계통연계형 태양광발전시스템의 고립운전방지를 위한 새로운 고리운전 검출기법을 연구한다. 이를 위하여 계통연계형 태양광발전시스템 및 고립운전시의 특성에 대하여 기술하였다. 또한 고립운전의 검출특성을 향상시키기 위한 새로운 검출기법을 제시하고 해석하였으며 검출시험을 위한 부하조건 선정을 위한 부하임피던스 곡선을 해석적으로 유포하였다 ACSL 시뮬레이션 및 실험을 통하여 제시한 고립운전 검출기법 및 해석결과를 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1050-1052
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• 2000

An investigation into power conditioners that interface with photovoltaic array and utilities has been completed. The rating for this investigation is residential system (3-5kW) that interface with a 220V single phase utility connection. As the result of this investigation. a 3kW high frequency PWM IGBT inverter feeding a high frequency isolation transformer with a sinusoidal current wave was selected. The output of the transformer rectified with a diode bridge rectifier four IGBT, used as 60Hz switched, reverse the polarity of the rectified current on every other half cycle of the utility voltage. Even though the high frequency link system used more power semiconductors, a net size, weight, and parts cost saving result compared to the other systems due to elimination of 60Hz transformer.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.100-102
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• 2008

As Utility interactive fuel cell systems are widely used, it is required for each power conditioning system(PCS) to have higher generating performance and more stable connecting characteristics. This study is focused to minimization of power losses and hence higher efficiency related to the new half bridge type 3-stage utility interactive PCS topology. The loss factor of half-bridge converter becomes only 1.2[%] under the rated load, and hence total efficiency is maintained to be higher as 91[%].