Takagi–Sugeno–Kang Fuzzy Controller-based Single-Stage Grid-Connected PV System

Abstract

Grid-connected solar power plants are widely established in many places worldwide. Photovoltaic (PV)-based grid connected solar plants are attracting recently due to improvement in controlling of power converters. Single-stage grid-connected systems can reduce the number of converters connected in power plants which result in reducing the cost of the system. However, DC to DC converters are generally used in PV systems to enhance the operation of maximum power point for best utilization. The inverters also can be used to extract maximum power from PV systems through new controlling techniques in power electronics devises. Therefore, an extra DC to DC converter is not required to make PV at its maximum power point condition. However, this technology can be used for small-scale solar power plants since all PV arrays in solar power plant cannot receive the same irradiance. Takagi–Sugeno–Kang (TSK) fuzzy controller has significant priority than proportional plus integral controllers when rapid changes are there in input. Hence, TSK-based single-stage controller is developed in this paper for grid-connected 1MW solar plant. Generally distribution system is connected with unbalanced loads, hence these unbalanced loads will create forcefully unbalanced currents in electrical grid. Unbalanced grid currents further create many problems to other loads. Therefore, the proposed controller is designed to help making grid currents balanced during unbalanced local loads. Further, the inverter can compensate reactive power demanded by local loads to minimize reactive power supplied by grid. Extensive results are presented and evaluated through hardware-in-loop on the platform of OPAL-RT to enhance the performance of the proposed controller for 1MW grid connected solar plant.