| 摘要 |
PURPOSE:To improve the speed controlling accuracy of low speed by increasing the sampling period inversely proportional to the detected value when the speed detected value is less than the specified value, and exponentially reducing the proportional constant of the proportional integration in correlation to the increase in the sampling period. CONSTITUTION:A DC motor 1 is driven by a thyristor converter 2 and controlled in response to a speed control signal 104. The speed of the motor 1 is detected by a speed detector 4, and inputted to a microprocessor 7 through a sampler 5, and compared with speed instruction value NR101. It is also supplied through a sampler 21 to a sampling period setter 22, which outputs a signal inversely proportional to the speed detected value from a sampling period to a sampling period signal generator 11 when the detected speed is less than the specified value, and simultaneously outputs the altered sampling period signal to a speed controller 20. The controller 20 exponentially reduces the proportional constant of the proportional integration in correlation to the increase in the sampling period. Thus, the speed controlling accuracy at the low speed time can be improved. |
