| 摘要 |
PROBLEM TO BE SOLVED: To stop a motor in a short period of time at the time of a system failure while preventing a failure of a short-circuit switch connected between DC power supply lines. SOLUTION: A control circuit 24 opens relay contacts 2a (2R, 2S and 2T) and outputs OFF command signals to IGBTs Q1-Q3 and on-signals to IGBTs Q4-Q6, when detecting an error signal Fo from a drive circuit 23. Simultaneously, the on-command signal is outputted to a MOSFET Q7 of a regeneration circuit 11. Then, the on-command signal is outputted to the MOSFET Q8 when a DC voltage VDC detected by a voltage detection circuit 27 drops to a prescribed threshold voltage (60 V, for example) determined according to a withstand capacity of the MOSFET Q8 or lower. COPYRIGHT: (C)2007,JPO&INPIT
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