Optimum switching points for array reconfiguration controller

The authors present a technique for finding the irradiance levels for optimum switching of photovoltaic (PV) powered water pumping systems operating with a multistage electrical array reconfiguration controller (EARC). Depending on the starting current requirements and the irradiance levels, the EARC reconfigures a PV array to be in parallel connection at a low irradiance level and in series connection at a high irradiance level. In this way, the quality of load matching in a PV power system will be improved because at low irradiance levels the power available to the motor in parallel connection is greater than the power available in a series connection and vice versa at higher irradiance levels. Optimum switching occurs when the power output of a parallel-connected array equals the power output of a series-connected array for a given irradiance level