| 摘要 |
PROBLEM TO BE SOLVED: To eliminate distortion and steep change in an energizing current waveform for reduction in motor noise by dividing an energizing logic signal of three-phase motor winding into a plurality of energizing zones, and energizing the inverter circuit of a winding drive with a PWM pulse. SOLUTION: A signal having a first zone whose area is from the start of energization of a three-phase six-mode energizing logic signal to 60 degrees is in the PWM, a second zone to the next 60 degrees is in the PWM of, 100% on and a third zone is in the PWM whose on duty factor is reduced gradually to the first half of the remaining 60 degree, is added to an inverter circuit transistor group of a three-phase motor winding drive for energizing. In the first energizing zone, a state in which the U and V-phase lower arms of an inverter circuit 8 are in the PWM and the V-phase upper arm is in the solid (namely, 100%)-on mode, and the lower arm is in the PWM obtained. In the next zone, the U-phase lower arm is in the solid-on mode and the V and W- phase upper arms are in the PWM, and the upper arm is in the PWM is obtained. In the last zone, the U and V-phase lower arms are in the PWM and the W-phase upper arm is in the solid-on mode, and the lower arm is in the PWM is obtained. |
