Research of photovoltaic charging system with maximum power point tracking

According to the output characteristics of photovoltaic (PV) array and battery charging characteristics, designed a PV charging system with maximum power point tracking (MPPT). This paper proposes a MPPT strategy based on DC/DC converter output current, which adopts variable step of duty cycle to implement MPPT of PV array. This perturbation and observation (P&O) method simplified the structure of the system, improved the speed and accuracy of tracking. In battery charging management, this paper adopts optimal charging strategy, charging controller combined MPPT charging and variable intermittent current charging increases the charge speed, raises the state of charge. Uses an efficient and reliable rules to determine the end of charging, avoids the over charging of battery and extends the lifetime of battery.