Single Phase Induction Motor Speed Regulation Using a PID Controller for Rotary Forcespinning Apparatus

Rotary forcespinning (RFS) is a simple method of fabricating fibers with a high production rate and low production cost. It can modify fibers morphology by varying polymer concentration, the solution flow rate, and the speed of induction motor. The change in the motor speed affects fibers diameter distribution. Therefore, it is necessary to implement a PID (proportional-integral-derivative) controller to maintain the stability of the speed during fibers production. A dimmer circuit to control the AC voltage supplied to the induction motor and a rotary encoder with a signal conditioner to measure the motor speed were used to regulate the motor speed. By applying the second Ziegler-Nichols tuning method, the PID controller constants, which are Kp, Ti, and Td, were obtained; Their values were 0.001242, 5, and 1.25, respectively. From the control system responses for the set points in the range of 16,000 to 28,000 rpm, it was shown that the control system has a fast response. In addition, a maximum overshoot of 345 rpm at the set point of 24,000 rpm and a maximum steady-state error of 335 rpm at the set point of 28,000 rpm were also obtained by the control system. Under a disturbance of 5 s given to the control system, the speed could be restored back to its original state within 34 s. Therefore, the speed regulation system was regarded as a good control system.