Design of battery charging circuit through intelligent MPPT using SPV system

In a solar photovoltaic (SPV) based hybrid renewable energy system, batteries are used as a power reservoir. SPV system provides energy under steady operating condition whereas SPV along with batteries serve as the source of energy under transient operating condition. This paper puts forward the design of a battery charging circuit through an intelligent fuzzy logic based discrete proportional-integral-derivative (FL-DPID) maximum power point tracking (MPPT) algorithm. SPV system in conjunction with FL-DPID MPPT technique driven DC-DC boost converter enhances the output voltage besides tracking maximum power point (MPP) under varying irradiance in between 400-1000 W/m(2) and a constant temperature of 25 degrees C. The output voltage of the boost converter drives the optimal PID (O-PID) controlled buck converter to behave as a battery charging circuit under non deterministic atmospheric conditions. The objective of this study is to operate the designed SPV system at MPP under varying environmental condition in order to achieve higher efficacy, minimize overall system cost and obtain apropos voltage and current for effective charging of battery thereby reducing battery losses and enhancing life cycle. A 200 W prototype of an SPV panel has been designed, simulated and investigated in the MATLAB/Simulink environment.