An Advanced Closed-Loop Control to Improve the Performance of Hybrid Stepper Motors

This paper presents an effective closed-loop control approach for a stepper motor. The proposed approach consists of motor parameter identification, closed-loop current control, closed-loop position control, and damping control. The presented implementation achieves accurate position, high torque, and smooth speed. By using an improved proportional-integral current control algorithm, this approach not only guarantees the current tracking performance but also increases the bandwidth during the speed response. The advanced position controller achieves both high torque and the synchronous condition of the motor after a loss of synchronism occurs. In addition, this method applies an effective speed damping method to remove resonance at low speed and reduce vibration at high speed. All the proposed algorithms were implemented on an industrial test-bench. The experimental results demonstrate the validity of the proposed approach for practical applications.