| 摘要 |
PURPOSE:To reduce torque pulsation and noises by a method wherein either a first PAM waveform or second square PAM waveform is selected out of memory for the control of a motor according to if the motor is in low-frequency operation or in high-frequency operation. CONSTITUTION:For a low-frequency operation, a switching signal producing a pulse waveform including less quantities of higher harmonics is supplied to an inverter 6 via a digital output circuit 14 and gate pulse amplifier 10, which reduces torque pulsation. For a high-frequency operation, a processor 17 reads a square wave-forming switching pattern out of a memory 18 and, according to the cycle determined by a timer 16, outputs the received pattern to the inverter 6 via a digital output circuit 11, gate pulse amplifier 10, and the inverter 6 is switched by the square wave-forming switching pattern. With the unit being designed as such, noises otherewise to accompany high-frequency switching are prevented. |
