Input voltage control of SEPIC for maximum power point tracking

The SEPIC (Single Ended Primary Inductor Converter) topology is an excellent choice for a maximum power point tracking (MPPT) converter in small solar energy systems. To achieve MPPT, the input voltage of the SEPIC, corresponding to the photovoltaic (PV) module's output voltage, must be regulated. In this paper, a model is derived with the voltage on the input capacitor as the plant output. The model is used to design a closed-loop controller to regulate the PV module voltage to match the output of an MPPT algorithm. Simulation and experimental validation are given.