PID controller with feedforward low pass filters for permanent magnet stepper motors

In this paper, PID controller with feedforward low pass Alters (FLPFs) is developed to guarantee desired currents for a permanent magnet stepper motor (PMSM). The proposed method consist of position controller and FLPFs. The position controller consists of a PID controller, a commutation scheme, and a Lyapunov based controller. To generate the desired torque, the PID controller is incorporated. Commutation scheme is developed to generate the desired currents. Lyapunov based controller is used to guarantee the desired currents. The FLPFs are developed to filter out high frequency noises of measured state and compensate for the phase lag caused by the conventional LPFs. Using the Lyapunov theory, we prove that globally asymptotical stability of currents errors is ensured by the proposed method. Experimental results validate the effectiveness of the proposed method.