Abstract: A novel lead-acid battery charge control strategy and maximum power point tracking algorithm for photovoltaic system are presented. A method of single polarity SPWM modulation for inverter is implemented. Experimental results show that the output power of photovoltaic array is fully utilized, the time of overcharging is significantly reduced, and charging efficiency is improved and battery lifetime prolonged due to higher-level state of the charge operation. Compared with the traditional modulation, the lowest harmonic frequency is improved under the same condition. Furthermore, design of the output filter becomes easier.

Key words: charge control, maximum power point tracking(MPPT), photovoltaic system