| 摘要 |
PROBLEM TO BE SOLVED: To realize high output and size reduction of a motor of a device by restraining the ratio of a torque fluctuation to average torque within a specific rate in a torque ripple of the motor, and setting a hysteresis width and a response frequency of a torque detecting means and a frequency band of torque control to a specific value. SOLUTION: A torque ripple is caused by nonuniformity of a magnetic flux and turbulence of rectification. Among these, torque caused by turbulence of rectification is reduced to the possible minimum level, and the torque ripple caused by nonuniformity of the magnetic flux is allowed up to a controllable level (within 10% of the ratio of a torque fluctuation to average torque). A driver can feel torque pulsation not less than 0.3 N.m on a steering wheel shaft up to a frequency not more than 60 Hz. Thus, detecting hysteresis of a torque sensor is set not more than 0.3 N.m (A<=0.3 N.m), a response frequency is set not more than 20 Hz, and the torque ripple is detected to correct the influence by a control system. A frequency band of a torque control system is set not less than at least 20 Hz. |
