Analysis and design optimization of photovoltaic water pumping systems

Three photovoltaic (PV) water-pumping systems were analyzed to develop techniques for optimizing system efficiencies. Centrifugal pumps driven by DC motors were operated from PV arrays with the same maximum power rating: one direct-coupled to a fixed array; another direct-coupled to a passive sun tracking array; and a third with a fixed array and operating with a maximum power point tracker (MPPT). Performance was monitored and compared for different head profiles and array series-parallel configurations. Tracking arrays can improve performance of direct-coupled systems over fixed arrays more than the insolation enhancement. Systems incorporating a MPPT perform optimally for a variety of array configurations.