| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an uninterruptible power supply system capable of decreasing loss, achieving device miniaturization and reducing cost by removing a resistor through which a current flows constantly. <P>SOLUTION: In a dual conversion feed type uninterruptible power supply system, a series circuit of a relay contact 4 and the resistor 5 for discharge is connected at both ends of the relay contact 2, and the relay contact 4 is turned on when an AC power supply 1 is recovered and DC intermediate capacitors 6 and 7 are charged by a backup power supply 15 to step up a voltage. In the uninterruptible power supply system, a first discharge path containing a capacitor 7, the relay contact 4, the resistor 5 for discharge, an IGBT for a semiconductor switch 9 in a parallel converter and the AC power supply 1 and a second discharge path containing the capacitor 6, the relay contact 4, the resistor 5 for discharge, the IGBT for the semiconductor switch 8 in the parallel converter and the AC power supply 1 are formed respectively in response to the positive or negative voltage of the AC power supply 1. <P>COPYRIGHT: (C)2010,JPO&INPIT |
