Patent ID: 11888422
Assignee: NIPPON STEEL CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 2:
3. A carrier frequency setting method for setting a carrier frequency in an inverter for driving a motor, comprising:
a loss derivation step of deriving a total loss which is a sum of a loss of the inverter and a loss of the motor when the motor is driven using the inverter while changing each of a torque generated in the motor, a rotation speed of the motor, and a carrier frequency in the inverter;
a carrier frequency derivation step of deriving a carrier frequency when the total loss is minimum as an optimum carrier frequency in each combination of a plurality of the torques and a plurality of the rotation speeds, based on the total loss derived in the loss derivation step;
a relationship derivation step of deriving a relationship between the torque of the motor and the optimum carrier frequency for each rotation speed of the motor, based on the optimum carrier frequency derived in the carrier frequency derivation step;
a relationship storage step of storing the relationship derived for each rotation speed of the motor in the relationship derivation step; and
a carrier frequency setting step of setting the carrier frequency according to a command value of the torque of the motor and a command value of the rotation speed of the motor based on the relationship after the relationship is stored in the relationship storage step, when the motor is driven,
wherein the inverter has a switching element configured using a semiconductor other than a wide band gap semiconductor, and
wherein in the relationship between the torque of the motor and the optimum carrier frequency derived for each rotation speed of the motor in the relationship derivation step, the optimum carrier frequency has a substantially constant value regardless of the torque of the motor.