The speed regulating module adopts discrete PID algorithm.
The inputs of the module are n∗ and n . n∗ is the reference
signal (r ⋅ min) and n is the feedback signal of the rotating
speed. The output signal has negative saturated limiting value
and positive saturated limiting value. The saturated limiting
value is the maximum current value. Fig.7 is the structure of
the speed control module.