Performance improvement of photovoltaic power generation systems using on-off control methods

The purpose of this work is to investigate the output power improvement of photovoltaic power generation systems using ON-OFF control methods. In the photovoltaic power generation system, the disturbance of the solar illuminance between the solar cells causes the imbalance of the internal resistance in each solar cell, and lowers the performance of the MPPT operation of the total photovoltaic power generation system. To overcome this problem, the authors investigate the feasibility of ON-OFF control methods in order to improve the MPPT operation. In the ON-OFF control methods, the solar cell module, which has a higher internal resistance due to a lower solar illuminance, can be disconnected in order to avoid the decrease in the total output power of the photovoltaic power generation system. Moreover, the disconnected solar cell module by the ON-OFF control method can be connected in parallel in order to extract the higher output power from the total photovoltaic power generation system. The authors demonstrated the validity of the ON-OFF control method using a small experimental model of a domestic photovoltaic power generation system.