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

Claim 5:
6. A carrier frequency setting device for setting a carrier frequency of an inverter for driving a motor,
wherein the carrier frequency setting device,
as a relationship between a torque of the motor and an optimum carrier frequency which is the carrier frequency when a total loss, which is a sum of a loss of the inverter and a loss of the motor when the motor is driven by using the inverter, is minimum,
derives, for each rotation speed of the motor, a relationship which has a portion in which the optimum carrier frequency increases as the torque of the motor increases in a range in which the torque of the motor is equal to or more than a torque of the motor corresponding to the carrier frequency at which the optimum carrier frequency is a lowest value, and a portion in which the optimum carrier frequency decreases as the torque of the motor increases in a range in which the torque of the motor is equal to or less than the torque of the motor corresponding to the carrier frequency at which the optimum carrier frequency is the lowest value, when the inverter has a switching element configured using a wide band gap semiconductor,
derives, for each rotation speed of the motor, a relationship in which the optimum carrier frequency has a substantially constant value regardless of the torque of the motor, when the inverter has the switching element configured by using a semiconductor other than the wide band gap semiconductor, and
sets the carrier frequency of the inverter based on the relationship between the torque of the motor and the optimum carrier frequency.