| 摘要 |
PROBLEM TO BE SOLVED: To provide a control device for a vehicular electric motor, which has improved reliability and furthermore enables the failure thereof caused by a surge voltage to be suppressed without incurring cost increase due to accuracy improvement or speeding-up.SOLUTION: The control device for the vehicular electric motor includes: drive circuits 1 and 2 each for controlling drive of an electric motor M; and cut-off means 3U, 3V and 3W which are disposed on drive lines 14U, 14V and 14W and include semiconductor switches and diodes D7-D9 connected in parallel with current passages of the semiconductor switches. When cutting off current supply from the drive circuits to the electric motor, the semiconductor switches are turned off when a current in a direction parallel with a forward direction of the diodes flows in the semiconductor switches. When a forward current flows in the diodes, there is no sudden current change and a high surge voltage is not generated even if the semiconductor switches are turned off, so that failures of the semiconductor switches can be suppressed. |
