| 摘要 |
PROBLEM TO BE SOLVED: To provide a power conversion device which can continue to operate without a system stopped in the case of a temporary factor when performing redundancy switching due to DC overvoltage failure.SOLUTION: A power conversion device comprises: two power converters 1A, 1B which obtain AC voltage by converting AC voltage into DC by a converter and giving it to an inverter; and a control unit 3 which selects one of th converters, monitors operation, and controls speed of an AC motor 2 with a rotation speed detector 4 according to a speed command given. The control unit 3 is provided with failure detection means 35 which determines whether each power converter has failure by DC overvoltage or otherwise and detects failure. When the failure detection means 35 detects failure by a factor other than DC overvoltage while one of power converters is being operated, operation control of the power converter is switched to the other; and when DC overvoltage failure is detected, as long as a speed command is speed feedback detected by the rotation speed detector 4 or larger, operation control of the power converter is switched to the other. |
