| 摘要 |
PROBLEM TO BE SOLVED: To restart an inverter without exceeding the withstand voltage of a switching element. SOLUTION: When an induced voltage of a synchronous motor 6 is estimated, based on a detected value Nm of a motor rotating speed and a detected value Tm of motor coil temperature, a motor rotating speed Nm is detected during the closing of a key switch 11, and the estimated value of a motor induced voltage has exceeded the withstand voltage of a switching element of a power conversion circuit 4, then the drive of a synchronous motor 6 by a power conversion circuit 4 is prohibited. By doing this, the drive of the synchronous motor during the rotation can be restarted by a power conversion circuit without raising the withstand voltage of the switching element of the power conversion circuit and without exceeding the switching withstand voltage. |
