Grid Interfacing of Multi-megawatt Photovoltaic System under Normal and Partial Shading Conditions

Weather conditions have several impact on the photovoltaic (PV) system power generation. Interfacing PV system to the grid is done by using power electronic devices and frequent switching results in various disturbances and power losses. With PV grid integration, many grid requirements have been provided to guide the interconnection procedures. These regulations only address issues associated with the performance of power electronic devices, however, do not address control issues in grid interfacing system. Control in grid connected PV system such as maximum power point tracking (MPPT), grid current and dc link voltage control have been given significant attention. In this paper, MPPT, grid current and dc link voltage control are reviewed. A new 0.8Voc model MPPT technique for active power optimization is proposed for grid interfacing of multi-megawatt PV system. The results show that an optimum active power can be injected into the grid. The design principles and theoretical analysis are presented while the feasibility is validated by simulation in grid interfacing multi-megawatt PV system.