| 摘要 |
PROBLEM TO BE SOLVED: To provide a backup device having a low cost and a small size by enabling continuous operation even when a power supply is abnormal or when a semiconductor switch fails in operation. SOLUTION: An AC-AC power converter includes a matrix converter for converting a polyphase AC voltage into a polyphase AC voltage via a virtual rectifier and a virtual inverter. The AC-AC power converter synthesizes control pulses to the virtual rectifier and the virtual inverter and imparts the synthesized pulse to the matrix converter. The AC-AC converter further includes a power supply fault detecting means 70 for detecting the fault of the polyphase AC voltage of the power supply side, a changeover switch 80, a DC power supply 83 for supplying a DC voltage to the input side of the virtual rectifier instead of the polyphase AC voltage supplied to the virtual rectifier, and a rectifier control means 40 for turning on the predetermined semiconductor switch and turning off the other semiconductor switch according to a switch-on command so that the DC voltage is present at the virtual DC link of the matrix converter 30. COPYRIGHT: (C)2004,JPO&NCIPI
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