• International Journal of Precision Engineering and Manufacturing-Green Technology
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• 제5권5호
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• pp.623-630
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• 2018

The renewable energy systems have been in the spotlight as an alternative for environmental issues. Therefore, the governmental policies are being implemented to spread of promote power generation system using renewable energy in various countries around the world. In addition, Korea has also developed a policy called the power trading contract which can profit from electricity produced from renewable power generation system through Korea Electric Power Corporation (KEPCO) and Korea Power Exchange (KPX). As a result, the power trading contracts can trade power after self-consuming in-house by using small-scale renewable power system for residential customers as well as electricity retailers. The power trading contracts applicable as a small-scale power system have a 'Net metering (NM)' and a 'Power Purchase Agreement (PPA)', and these two types of power trading contracts trade surplus power, but payment method of each power trading is different. The microgrid proposed in this paper is based on grid connected microgrid using Photovoltaic (PV) system and Energy Storage System (ESS), that supplied power to residential demand, we evaluate the operation cost of microgrid by power demand in each power trading contracts and propose the appropriate power trading contracts according to electricity demand.

• 한국방사선학회논문지
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• 제5권3호
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• pp.127-134
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• 2011

본 논문에서는 온도와 습도 및 냉 난방을 조절하여 건물 내의 쾌적한 환경을 제공하기 위한 승압쵸퍼와 PWM 전압형 인버터로 구성된 태양광 발전 시스템을 제안하였다. 이 시스템은 안정된 변조를 위해 원칩 마이크로프로세서를 사용하여 동기신호와 제어신호로 처리하였다. PWM 전압형 인버터와 위상의 동기를 위하여 계통전압을 검출하여 계통전압과 인버터 출력을 동상 운전하므로 잉여전력을 연계할 수 있게 하였으며, 건물이나 병원 등 특정 건물의 온도 및 습도센서에 적용하여 양호한 동특성을 얻을 수 있었다. 또한 시스템에 적용한 결과 고역률과 저고조파 출력을 유지함으로써 부하와 계통에 전력이 안정하게 공급될 수 있도록 제어하여 좋은 결과를 얻을 수 있었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.117-120
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• 2004

As the maximum power operating point (MPOP) of photovoltaic (PV) power generation systems changes with varying atmospheric conditions such as solar radiation and temperature, an important consideration in the design of efficient PV system is to track the MPOP correctly. Although the efficiency of these Maximum Power Point Tracking algorithms is usually high, it drops noticeably in case of rapidly changing atmospheric conditions. This paper describes common MPPT control algorithm: Constant Voltage Control, Perturbation and Observation(P&O), Incremental Conductance (IncCnd) and proposes a new MPPT algorithm based on P&O algorithm. The conception and control principles of the proposed MPPT method are explained in detail and its validity of the proposed method is verified through several simulated results. As it doesn't use digital signal processor, this MPPT method has the merits of both a cost efficiency and a simple control circuit design. Therefore, it is considered that the proposed MPPT method is proper to low power, low cost PV applications.

• 한국전자통신학회논문지
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• 제17권2호
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• pp.299-308
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• 2022

최근 에너지전환정책은 소규모 태양광발전기 수량을 증가시키고 있다. 계통운영자는 이러한 소규모 태양광 발전량을 정확하게 예측하기가 어렵고 급전계획을 방해할 수도 있으며, 결과적으로 비용상승이 초래될 것이다. 이러한 문제를 해결하는 방법으로 소규모 태양광발전소에서 생산되는 발전량, 전압제어에 대하여 불확실성을 줄이고 예비전력을 공급하는 소규모 태양광발전소의 집합체로서 가상발전소가 떠오르고 있다. 본 연구에서는 가상발전소 클라우드 요금산정을 위하여 순현재가치법과 수익성지수법을 사용하며, 두 종류의 비용평가법 계산결과가 상세하게 설명된다. 계산결과로부터 수익성지수가 1.22로 산정되어 수익성을 확보한 것으로 나타났으며, 순현재가치가 수익성을 충분히 만족시키기 때문에 중개사업자 관점에서 매력적이다.

• 전력전자학회논문지
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• 제26권5호
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• pp.342-348
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• 2021

The PV module of solar power systems requires maximum power point tracking (MPPT) technique because the power-voltage and current-voltage characteristics vary depending on the surrounding environment. In addition, the 120 Hz ripple voltage on the DC-Link is caused by the imbalance of the system voltage and current. The effect of this 120 Hz ripple voltage reduces the efficiency of the power generation system by increasing the output current distortion rate. Increasing the capacity of DC-Link can reduce the 120 Hz ripple voltage, but this method is inefficient in price and size. We propose a technique that detects 120 Hz ripple voltage and reduces the effect of ripple voltage without increasing the DC-Link capacity through a controller. The proposed technique was verified through simulations and experiments using a 1 kW single-phase solar power system. In addition, the proposed technique's feasibility was demonstrated by reducing the distortion rate of the output current.

• 플랜트 저널
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• 제17권4호
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• pp.41-52
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• 2021

본 연구에서는 태양광발전 출력 및 모듈온도 값을 기상청 데이터를 이용하여 예측해보고 실측 데이터와 날씨, 일사량, 주변온도, 풍속별로 비교 분석해보았다. 날씨별 예측정확도는 눈이 오거나, 새벽에 해무가 끼는 날의 데이터를 가장 많이 보유한 맑은날의 데이터의 예측정확도가 가장 낮았다. 일사량에 따른 모듈온도와 발전량의 예측정확도는 일사량이 커질수록 정확도가 떨어졌으며, 주변 온도에 따른 예측정확도는 모듈온도는 주변 온도가 커질수록, 발전량은 주변온도가 낮을수록 예측정확도가 떨어졌다. 풍속은 모듈온도와 발전량 모두 풍속이 높아질수록 예측정확도가 감소하였지만, 풍속이 영향 다른 기상조건에 의한 영향보다 미미하여 그 상관관계를 정의하기가 어려웠다.

• 전기학회논문지P
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• 제65권3호
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• pp.219-223
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• 2016

DC microgrid system is attracted attention in the world, because DC distribution system is more energy efficient than AC distribution system. To analyse the contribution effects of distributed generation(DG) in LVDC distribution system through modeling the Rectifier, DC/DC converter, Energy Storage System(ESS) and Photovoltaic(PV). using PSCAD/EMTDC. This paper analyses fault response characteristics in LVDC distribution system according to the interconnection and islanding operation of DG. Based on research results on the paper, direction for development of fault current reduction method for LVDC distribution system is suggested.

• Current Photovoltaic Research
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• 제11권1호
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• pp.27-33
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• 2023

In this paper, a machine learning model by using a regression algorithm is proposed to estimate the power generation performance of the BIPV system. The physical model formula for estimating the generation performance and the proposed model were compared and analyzed. For the physical model formula, simple efficiency model, temperature correction model, and regressive physics model for changing an irradiance were used. As a result, when comparing the regressive physics model for changing an irradiance and the proposed model with the actual generation measured data, the respective RMSE values are 0.1497 kW, 0.0451 kW and the accuracy values are 86.44%, and 96.56%. Therefore, the proposed model implemented in this experiment can be useful in estimating power generation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.953-956
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• 2003

Digital environment that is represented to internet is displacing business way of industry and business achievement way with the fast speed being giving great change on life whole, improve existence business process utilizing internet and Web connection technology, information superhighway to tradition industrialist manufacture and e-transformation's propulsion that wish to maximize productivity and administration efficiency Is spread vigorously. In this paper, we wish to accomplish generation equipment's heighten stability and believability through remote monitoring and control of PV system. This paper describes the design of the monitoring system for sensing the monitoring data and indirect controlling of the PV system. Most of the conventional monitoring system depend on the special hardware and software. Basic design goal of monitoring system is to provide the convenience for the user and the portability for the system. In order for the system to fulfill its requirements, it was designed using Labview GUI facility based on the Windows 2000 environment of IBM PC compatible and Add-on card based on the TCP/IP protocol. Advantage of the monitoring system are a personnel expenses curtailment effect, free of the place restriction and unmanned system of the generation plants, etc..

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.724-729
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• 1998

In general, a single-phase current-fed PWM inverter using IGBTs has some unique advantages for small scale distributed utility-interactive power supply system as compared with voltage-fed PWM inverter. In particular, this is more suitable and acceptable for a non-isolated type utility-interactive power conditioner, which is going to be widely used for residential solar photovoltaic (PV) power generation system in Japan. However, this current-fed PWM inverter has a significant disadvantage. The output current of this inverter includes large harmonic contents when the inductance of smoothing reactor in its DC side is not large enough to eliminate its current ripple components of this inverter. In order to overcome this problem, a new conceptual pulse area modulation scheme for this inverter is introduced in difference with conventional PWM strategy. This paper presents a new effective control implementation of this PV power conditioner which is able to reduce the harmonic component in the output current produced by the single-phase current-fed PWM inverter even when the ripple current in the smoothing DC reactor is relatively large. The operating principle of the proposed control strategy introdued for this inverter system is described, and its simulation results are evaluated and discussed herein.