Abstract: A first torque calculation unit 114 calculates torque TQ_DC currently generated by a motor 106 based on a DC current DC1. A second torque calculation unit 115 calculates torque TQ_UVW currently generated by the motor 106 based on U-phase, V-phase, and W-phase currents. A torque limit calculation unit 116 calculates a torque limit TQ_LMT1 using a torque limit characteristic map measured in advance based on a current limit DC_LMT1. A torque limit correction unit 117 compares first torque TQ_DC with second torque TQ_UVW to calculate a torque variation degree KP1. Then, the torque limit TQ_LMT1 is corrected using the variation degree KP1 to calculate a torque limit TQ_LMT2. As a result, even if required torque reaches the torque limit, the DC current does not exceed the current limit, and the output of the motor can be fully utilized by approaching the current limit.

Abstract: A first torque calculation unit 114 calculates torque TQ_DC currently generated by a motor 106 based on a DC current DC1. A second torque calculation unit 115 calculates torque TQ_UVW currently generated by the motor 106 based on U-phase, V-phase, and W-phase currents. A torque limit calculation unit 116 calculates a torque limit TQ_LMT1 using a torque limit characteristic map measured in advance based on a current limit DC_LMT1. A torque limit correction unit 117 compares first torque TQ_DC with second torque TQ_UVW to calculate a torque variation degree KP1. Then, the torque limit TQ_LMT1 is corrected using the variation degree KP1 to calculate a torque limit TQ_LMT2. As a result, even if required torque reaches the torque limit, the DC current does not exceed the current limit, and the output of the motor can be fully utilized by approaching the current limit.