Analysis of multistage flyback photovoltaic conversion system

An electrolytic capacitor used as a decoupling reservoir which restrict the lifetime of photovoltaic (PV) micro inverters‥ The project focuses on selection of the minimum decoupling capacitor value for the proper operation of discontinuous conduction mode fly back PV micro inverter by considering the total harmonic distortion (THD) and PV power utilization ratio. A decoupling capacitor selection method for single-stage and two-stage fly back inverters is proposed. For two stage inverters, the control method of the dc-dc converter determines the stage where the decoupling function takes place. Thus, the PV side decoupling capacitor should be dimensioned according to the PV power utilization ratio, and the inverter side decoupling capacitor should be selected according to the desired THD limitation. The corresponding voltage ripple limits for THD and PV power utilization.