To quickly and stably execute the maximum power control of a solar battery by reducing the maximum level of a reference operating voltage variation when the reference operating voltage is increasing and output power from the solar battery is increasing.
In a maximum power control circuit 23, a current of instructed level is outputted so as to make the operating point voltage of the solar battery 10 an open voltage, the current of instructed level is varied in a prescribed sampling cycle and the reference operating voltage is increased by a prescribed variation range. The voltage variation range is calculated to obtain a desired reference operating voltage based on a difference between the output power sampled at this time and the output power sampled at a previous time, that is the variation range of the output power of the solar battery 10. In this case, with the maximum value of the variation range of the reference operating voltage when the reference operating voltage is decreasing and the output power from the solar battery 10 is increasing. The maximum level of the reference operating voltage range, when the reference operating voltage is increasing and the output power from the solar battery 10 is increasing, is reduced.
KOSHIN HIROAKI
YOSHITAKE AKIRA
MUKAI CHUKICHI
ONO HIROYUKI
Next Patent: MAXIMUM POWER CONTROL METHOD FOR SOLAR BATTERY