| 摘要 |
PURPOSE:To reduce the drift to zero by digitally constructing a voltage control generator in a controller for an induction motor. CONSTITUTION:A speed detection pulse of a speed detector 5 is applied to a PLLD comprising a phase difference detection circuit 23, a low pass filter 24, a voltage control generator 25 and a divider 22. The output of the generator 25 is applied to a change-over circuit C through a synchronization circuit 26. On the other hand, the output of an absolute value converter 11 is applied to a voltage control generator 30, the output of which is applied to a change-over circuit C through a synchronization circuit 31. In addition, the output of a slide amplifier 8 is applied to a zero cross comparator 33, the output of which is applied to the change-over circuit. The output of a change-over circuit 36 is applied to an up/down counter 26. When the output of the amplifier 8 is negative, the output of the synchronization circuit 31 is up-counted while being down-counted when it is positive. |
