| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an uninterruptible power supply device that can feed power to a load from an AC power supply normally, and when power is interrupted or a voltage of the power supply is lowered, can uninterruptedly switch to power feeding by a power converter without detecting power interruption, is high in efficiency, small in size and low in cost. <P>SOLUTION: The uninterruptible power supply device comprises: a first bidirectional switch 11 connected between the AC power supply 1 and the load 5; a second bidirectional switch 12 connected between an inverter 3 that outputs AC power and the load 5; a detection means 10 that detects voltage polarity when the AC power supply is normal; and a means for turning on and off the first and the second bidirectional switches 11, 12 in accordance with the detected voltage polarity. Each bidirectional switch 11, 12 comprises at least two semiconductor switching elements that can independently control currents in both directions at input and output sides, and sets an output voltage of the inverter 3 lower than a normal voltage of the AC power supply 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
