| 摘要 |
PROBLEM TO BE SOLVED: To provide a refrigerator which obtains demagnetization current by more precisely calculating a temperature of a permanent magnet and can start a permanent magnet synchronous motor without occurrence of demagnetization by using a new temperature sensor without cost increase.SOLUTION: A refrigerator includes: temperature calculating means for calculating a temperature of a permanent magnet synchronous motor from winding resistance of the permanent magnet synchronous motor; and demagnetization current calculating means for calculating demagnetization current of the permanent magnet synchronous motor at the temperature from the temperature calculated by the temperature calculating means. A controller performs positioning processing for fixing a rotation angle of a magnetic pole in an arbitrary position by making a DC current lower than the demagnetization current calculated by the demagnetization current calculating means flow to the permanent magnet synchronous motor when the permanent magnet synchronous motor is started, makes an AC current lower than the demagnetization current calculated by the demagnetization current calculating means flow to the permanent magnet synchronous motor and performs synchronization starting processing for gradually increasing a frequency of the AC current. |
