| 摘要 |
PROBLEM TO BE SOLVED: To establish, with respect to a UPS system in which a single controller controls a plurality of UPS unit bodies, overcurrent protection of each unit body and improvement of reliability of the whole system.SOLUTION: A UPS unit body 2G comprises: a current detector 222 for detecting output current from an inverter 202; an overcurrent protection circuit 232 for cutting off gate pulse output to the inverter 202 to stop operation of the inverter 202, when the current detector's current detection value has exceeded a second overcurrent detection level; and contactors 203, 211 for performing parallel-off on the inverter 202. A controller 270 comprises: an overcurrent detection circuit 273 for stopping operation of all inverters 202 for a fixed period when a total value Iof current detection values has exceeded a first overcurrent detection level lower than the second overcurrent detection level; an off delay circuit 274; and a logical circuit 275; etc.SELECTED DRAWING: Figure 2 |
