Control of fuzzy logic based PV-battery hybrid system for stand-alone DC applications

The paper presents a hybrid system comprising of photovoltaic (PV) and battery with fuzzy logic control (FLC) to meet the demands of isolated off grid DC loads. Perturb and Observe (P&O) method is used to achieve the maximum power point tracking (MPPT) by controlling the duty cycle of a dc-dc boost converter. Fuzzy logic controller regulates the power flow of the battery by means of a bidirectional buck-boost converter. The complete energy management system has been validated in MATLAB/SIMUINK with variable solar irradiation profile. The simulation results show that the system with fuzzy logic control prolongs the battery lifespan by reducing the battery peak current up to 0.22% and also significantly decreases the settling time and peak overshoot of the DC load voltage up to 16.23% and 14.62% as compared to the system with conventional PID control.