| 摘要 |
PURPOSE:To enable continuation of operation of an AC motor by providing a control circuit for controlling the output current of alive converter to generate a current at normal time when one of the converters provided at respective phases of the motor malfunctions. CONSTITUTION:A cyclo converter 1 for driving a synchronous motor 2 compares the signal from a speed detector 4 with the output from a speed instructing circuit 5, and the output from a position detector 7 is applied to multipliers 8-10 for control. There is provided a control circuit 11 having switches 21-26 and adders 27-29 between the multipliers 8-10 and current deviation amplifiers 15-17. When one of the respective phased of the converter 1 malfunctions, the defective phase is separated, and a current instruction signal of the defective phase is applied thereto together with the original current instructing signal. Accordingly, the armature winding of the defective phase generates the electromotive force equal to the electromotive force induced at normal time in the alive phases to thus continue the operation of the motor with safety. |
