| 摘要 |
PROBLEM TO BE SOLVED: To recover the functions as a backup power supply in a short time even after the use of backup power supply and when the quantity of solar radiation is small in a power supply system utilizing solar cells and storage batteries as backup power supplies for a commercial power source. SOLUTION: Both the output voltage of a solar cell 3 and the output voltage of a storage battery 4 are always monitored; and a switch SW provided in a battery charging circuit 9 is turned on only when both the output voltages become lower than a predetermined ON values, thereby a battery 4 is charged by a DC current input through a rectifier 2 from a commercial power source 1 and the functions as a backup power supplies are recovered in a short time. |
