| 摘要 |
PURPOSE:To stop operation at abnormal operation securely, by a method wherein when abnormal operation occurs, AC power source is interrupted and ON- signal is supplied to a switching element thereby the element 3 is turned on. CONSTITUTION:A power converter is constituted by a converter 3, a DC reactor 4 and an inverter 5, and supplies power to an induction motor 7 as load. A control device thereof is constituted by a DC current detector 8, a comparator 8, one-chip microcomputers 10-11 for control, a DC current abnormal state detector 16 and the like. The microcomputer 10 is constituted by a ROM 103, a RAM 104, an ALU 105, an event setting register 107, a time setting register 108, a holding register 109, an associative memory 110, a timer 111, an execution controller 113 and the like. The abnormal state detector 16 detects abnormal state and outputs the operation stop signal to the control device and turns off a circuit breaker 2, and turns on all switching elements 31-36, 51-56. In this constitution, generation of high voltage due to the reactor 4 can be prevented.
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