POWER CONVERTER

PROBLEM TO BE SOLVED: To provide an uninterruptible power source device which can be applied to a three-phase three-wire system and a three-phase four-wire system dispensing with an insulating transformer, in which the device can be constituted compactly, lightly and inexpensively by lowering necessary DC voltage to lower the withstand voltage of the components used in the device. SOLUTION: The power converter comprises a converter circuit 23 with its input terminal connected to a three-phase AC power supply 21, a DC circuit consisting of capacitors 29a 29b and a battery 30, and an inverter circuit 26 with its output terminal connected to a three-phase load device 22 in which the converter input terminal and the inverter output terminal for each phase are connected via a switch 42 to constitute a by-pass circuit. Furthermore, the converter input terminal 49b and the inverter output terminal 50b of a v-phase of a grounding phase are directly connected with a jumper wire 43. COPYRIGHT: (C)2005,JPO&NCIPI