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Horie K.,Doshisha University | Takahashi Y.,Doshisha University | Fujiwara K.,Doshisha University | Ishihara Y.,Doshisha University | And 3 more authors.
IEEJ Transactions on Power and Energy | Year: 2014

This paper investigates the influence of MPPT control method in the PCS on the occurrence of reverse voltage in PV modules. When the power of modules in part of a PV array declines, a situation arises in which those modules must be replaced with modules of different rated value. In such a case, the difference in the characteristics of existing modules and replacement modules may cause the occurrence of reverse voltage by MPPT control of the PCS in the replacement modules, which may cause heat and ignition. Although protection devices are connected to protect the modules from the occurrence of reverse voltage, they may not work. Therefore, it is indispensable to clarify the range of safe combinations of modules of different rated value. First, an MPPT control algorithm of three kinds of PCSs is implemented. To validate the developed control algorithm the simulated operating voltage is compared with measured one. Second, in order to clarify the conditions under which reverse voltage is likely to occur, the influence of the MPPT operation, open circuit voltage and short circuit current of PV modules and the pattern of connection of existing and replacement modules in a PV array on the occurrence of reverse voltage is investigated. © 2014 The Institute of Electrical Engineers of Japan.


Eguchi Y.,Japan Electrical Safety and Environment Technology Laboratories | Ramu G.,Sunpower Inc | Lokanath S.V.,First Solar | Yamamichi M.,Japan National Institute of Advanced Industrial Science and Technology | And 4 more authors.
2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014 | Year: 2014

As the PV industry has grown, there is much concern in the markets about whether low photovoltaic (PV) module prices are leading to inferior products being introduced into the market. For protection of consumers, and also industries it is necessary to establish and standardize the suitable evaluation method of long-term reliability of PV modules. A quality management system for PV module production is one of the key elements to secure the long-term reliability of PV modules. This paper describes the requirements for quality management systems for PV module manufacturers to produce PV modules which secure the consistency of the design, production and product warranty. © 2014 IEEE.


Igarashi H.,Japan Electrical Safety and Environment Technology Laboratories | Igarashi H.,Tokyo University of Agriculture and Technology | Sato T.,Japan Electrical Safety and Environment Technology Laboratories | Miyamoto K.,Tokyo University of Agriculture and Technology | Kurokawa K.,Tokyo University of Agriculture and Technology
Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi) | Year: 2010

Photovoltaic generation systems must have protection devices and islanding detection devices if they are connected to utility lines of the electric power company. This is regulated in national technological requirement guidelines and the electric equipment technology standards. Islanding detection devices are installed to detect blackouts due to events such as ground faults and short circuits in utility lines. When an islanding detection device detects a power blackout, the photovoltaic generation system must be stopped immediately. It is known that islanding detection devices cannot detect islanding if induction motors are present among the loads. We investigated the influence of induction motors on islanding detection devices and found that when the frequency decreases after a utility line failure, induction motors change over to generator mode, thus compensating the active power imbalance and suppressing voltage variation. In addition, if the postfault frequency is adjusted by PLL control so as to maintain a fixed power factor, induction motors suppress this frequency change, thus extending islanding operation. It is clear from the above results that induction motors are more likely to produce islanding phenomena than static loads. © 2010 Wiley Periodicals, Inc.


Hayashi K.,Doshisha University | Takahashi Y.,Doshisha University | Fujiwara K.,Doshisha University | Ishihara Y.,Doshisha University | And 2 more authors.
IEEJ Transactions on Power and Energy | Year: 2013

In this paper, based on the data of field exposure test, which was initiated by Japan Electrical Safety & Environment Technology Laboratories (JET), we investigate the degradation characteristics of crystalline silicon PV modules by using its equivalent circuit model for the purpose of the lifetime extension in the development of PV modules. Specifically, we observe the degradation of bus bar electrode and solar cell by capturing electro luminescence images and infrared images of the surface of PV modules when forward voltage is applied. Although this observation enables us to determine which part of the PV module deteriorates, it is impossible to quantitatively evaluate how much each deteriorated component has an influence on power degradation. Accordingly, using the equivalent circuit model of the PV module, we calculate the equivalent circuit parameters from the measured I-V characteristics of the PV modules in the field exposure test by the least squares method. We adopt the photocurrent, series resistance, shunt resistance and diode factor as unknown parameters in the equivalent circuit model. Based on the change of the circuit parameters, we evaluate the influence of the deterioration of each component on decline of output power quantitatively. © 2013 The Institute of Electrical Engineers of Japan.

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