• Journal of Power Electronics
• /
• 제16권2호
• /
• pp.631-642
• /
• 2016

Usually, the output characteristics of a photovoltaic (PV) array are significantly affected by non-uniform irradiance which is caused by ambient obstacles, clouds, orientations, tilts, etc. Some local maximum power points (LMPP) in the current-voltage (I-V) curves of a PV array can result in power losses of the array. However, the output power at the global maximum power point (GMPP) is different in different interconnection schemes in a PV array. Therefore, based on the theoretical analysis and mathematical derivation of different topological structures of a PV array, this paper investigated the output characteristics of dual series PV arrays with different interconnections. The proposed mathematical models were also validated by experimental results. Finally, this paper also concluded that in terms of performance, the total cross tied (TCT) interconnection was not always the optimal structure, especially in a dual series PV array. When one of the PV modules was severely mismatched, the TCT worked worse than the series parallel (SP) structure. This research can provide guidance for switching the interconnection to gain the greatest energy yield in a changeable- structure PV system.

• 신재생에너지
• /
• 제1권2호
• /
• pp.11-18
• /
• 2005

A modular photovoltaic PCS with high-frequency isolation is proposed. The proposed system consists of a SEPIC converter and a full-bridge inverter Using the power slope versus voltage of the PV array, the MPPT controller is proposed that produces a smooth transition to the maximum power point. The dc current of the PV array is estimated without using a dc current sensor The disturbance of the line voltage is detected using a fast sensing technique. Experimental results obtained on a 500W prototype show high performance such as almost unity power factor, $90\%$ power efficiency, $3.6\%$ THD.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
• /
• pp.326-328
• /
• 1996

The 10kW or 1MW model of a photovoltaic array written in PSPICE is presented in this paper. A problem with this large scale centralized photovoltaic system is the decrease of power due to the resistance of cable connecting individual subarray with inverter. In this paper, we analyzed the relationship between the resistance of cable and subarray output power of 1MW photovoltaic system by the PSPICE modeling. As a result of simulation, we can proved that photovoltaic array output power is limitted by the resistance of cable.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2004년도 학술대회 논문집
• /
• pp.255-258
• /
• 2004

The SAR(Solar Array Regulator) of KOMPSAT(Korea Multi Purpose SATellite)-1, 2 regulates a photovoltaic power according to the duty ratio commands of the ECU. But the ECU has so many other jobs that it can not calculate the solar array condition immediately. It means the SAR cannot always generate the maximum power of a photovoltaic. Nowadays, the commercial photovoltaic systems are using a controller operated by digital processing. But the usage for satellite is not adaptable. It is not easy to find the processor of the space grade and the price is expensive. So in this paper, the simple analog MPPT(Maximum Power Point Tracking) algorithm is proposed for the small satellite in LEO. This algorithm does not need any calculation of power by multiplication of voltage and current md a measurement of the solar array temperature. It is consist of only two sample and hold circuits, two comparators, a flip-flop, and an integrator. The proposed MPPT algorithm is verified by the simulation and experimental.

• Journal of international Conference on Electrical Machines and Systems
• /
• 제2권1호
• /
• pp.65-68
• /
• 2013

A photovoltaic array exhibits several local and single global maximum power points under partial shading conditions. To track the global maximum power point precisely, a novel global maximum power point tracking scheme is proposed in this paper. In the proposed scheme, robustness of the tracking performance has been improved by enhancing searching profile. In addition, the paper addresses the tracking failure condition, and provides the experimental verification with several simulation and experimental results.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.987-992
• /
• 1998

Solar cell has an optimum operating point to extract maximum power. To control operating point of the solar cell, a fuzzy controller has already been proposed by our research group. However, several parameters are determined by trial and error. To overcome this problem, this paper adopts Fuzzy Neural Network (FNN) for maximum power point tracking control for photovoltaic array. The FNN can be trained to perfect fuzzy rules and to find an optimum membership functions on-line.

• 한국태양에너지학회 논문집
• /
• 제31권5호
• /
• pp.134-139
• /
• 2011

Since large and small scale photovoltaic(PV) systems have been commercialized in many countries, it is necessary to assess the effects of PV systems on the electric power system. For this, the development of accurate simulation model of PV arrays is very important. PSCAD/EMTDC, a widely used simulation tool for analyzing the transient behavior of electrical apparatus and networks, does not have a standard model of a PV array. Therefore in order to simulate the PV array, users have to develop their own simulation model. However, the block-diagram-based model is very complicated, and it is hard to modify the model parameters. In this study, we develop the user-defined model of a PV array by using the Design Editor, which is provided by PSCAD program. The mathematical model of a PV array and the method to determine the parameters of nonlinear I-V equation are implemented in a Fortran code. The graphical user interface provides the users with easy and simple way to modify the PV array parameters and simulation conditions. In order to help the users, this model also provides the parameters of 10 commercial PV arrays.

• 한국태양에너지학회 논문집
• /
• 제39권6호
• /
• pp.15-25
• /
• 2019

As the installation of photovoltaic systems increases, fire accidents of PV system grow every year. Most of PV system fires have been reported to be caused by electrical components. The majority of fire accidents occurred in combiner box, which is presumed to be short-circuit accidents due to dustproof and waterproof failures or heat deterioration of blocking diode. For this reason, the blocking diode installation became optional by revised PV combiner regulation. In this paper, according to the revised regulation, reverse current that generated by voltage mismatch was measured and analyzed in PV array without a blocking diode. The factors that cause voltage mismatch in array are assumed to be shaded PV module and short circuit failure of bypass diode. As the result of experiment, there is no reverse current to flow under shading condition in module, but reverse current flows on the failure of bypass diode in module. According to the module's I-V characteristic curve analysis, open voltage was slightly reduced due to operation of bypass diode in shading. However, it showed that open circuit voltage has decreased significantly in the failure of bypass diode. This indicates that the difference in open voltage reduction of voltage mismatch factor causes reverse current to flow.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2005년도 춘계학술대회
• /
• pp.132-135
• /
• 2005

A modular photovoltaic PCS with high-frequency isolation is proposed. The proposed system consists of a SEPIC converter and a full-bridge inverter. Using the power slope versus voltage of the PV array, the MPPT controller is proposed that produces a smooth transition to the maximum power point. The disturbance of the line voltage is detected using a fast sensing technique. Experimental results obtained on a 500W prototype show high performance such as almost unity power factor, $90\%$ power efficiency, $3.6\%$ THD.

• 한국태양에너지학회 논문집
• /
• 제36권4호
• /
• pp.57-65
• /
• 2016

Domestic photovoltaic system for roof-top is installed towards the south at an angle of 20 to 35 degrees and the shape of PV array is divided into two kinds; a plane shape and a curved shape. This paper aims to understand an actual condition of PV facility and strengths and weaknesses of support structure production and installation and to consider the best PV surface shape by analyzing theoretical logics of these two surface shapes and architectural perspective-based realistic case studies. This study targeted 98 facilities including common houses, public institutions and education institutions. In common houses, all of 59 PV facilities have a plane surface. In public institutions, 7 of 15 PV facilities have a curved array surface and 8 PV facilities have a plane surface. In education institutions, also, 14 of 24 PV facilities have a plane array surface and 10 PV facilities have a curved surface. Most of 98 facilities have a flat roof supporting shape. However, it was found that the curved shape wasn't positive for PV generation due to the change of radial density and it was at least 10 % more expensive to produce its structure. Also, domestic general large single-plate PV facilities have problems of harmony with buildings and wind load. Therefore, it is considered that for fixed-type roof-top PV, a plane PV array shape is good for optimum generation and economic efficiency and a parallel array structure on the roof surface is favorable to wind load and snow load without being a hindrance to the building facade.