| 摘要 |
PROBLEM TO BE SOLVED: To provide a UPS system capable of exactly detecting failure in a bypass switch.SOLUTION: The UPS system turns off an input switch S1 when a power failure occurs (time t1) to stop a converter 6 and hence an inverter 11 converts DC power of a battery 8 into AC power. When a bypass switch 5 is not off even with a control signal CNT at "L" level and the converter 6 that has once stopped is operated (time t2), an output current I1 of the inverter 11 runs into the converter 6 through the bypass switch 5, so that the electric current I1 increases. When the electric current I1 increases, the bypass switch 5 is determined to be abnormal. |
