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Abstract:The maximum power point of PV (photovoltaic) generation moves depending on weather conditions and load. Therefore, it is significant to make sure that the panels can work at the maximum power point under MPPT (maximum power point tracking) control. However, it has the problems of low efficiency and unstable operation when panels are covered by the partial shadow. The result is that the output power may be substantially decreased. To overcome this issue, the authors propose a new plug-in operation point correction system. This system is put between PV panels and PCS (power conditioning system) in the existing PV generation system. In this paper, the experimental results describe that the output electric energy increases approximately 1.4 times as compared with the conventional system when the proposed correction system is inserted.

Currently, the production and installation quantity of photovoltaic modules has been increasing rapidly. Meanwhile, the failure cases are also increasing. Accordingly, many failures are results of the Hot-Spot phenomenon. This is a phenomenon in which the entire or part of the defective cell becomes hot when shadow occurs on the cell for a long period. In severe cases, the phenomenon causes breaking of the cell and a fire. While there are many Hot-Spot inspection methods, such as using infrared cameras, the inspection instruments of these methods are expensive, and these methods also require a lot of time and effort during the inspection. Previously, the authors proposed a Hot-Spot detection system included into PCS. In this paper, we proposed plug-in type Hot-Spot detection system, and report about effectiveness of the system.