| 摘要 |
PURPOSE:To stably control for an object to be controlled in which a load torque is largely varied in a transient period for shifting from the start to a constant speed operation of a DC motor by providing an interval timer for updating the operating amount of a PWM. CONSTITUTION:An interval timer for updating the operating amount of a PWM is provided to set a PWM period. Here, the set value of the interval timer is made longer than the target value of a PWM pulse period and sufficiently smaller than the mechanical time constant of a DC motor, and the PWM period is set to a non-audible range. When the DC motor is started, the operating amount (conducting time) of the PWM is gradually increased at each interval timer. When the PWM pulse period arrives at a period slightly longer than a target value, it is switched to a PI control. In the first PI calculation, the value obtained by removing an integration gain from the operating amount of the PWM at the present time is set in a PWM register. |
