Hardware simulation of semi-decoupled tuning gain anti-windup PI controllers for motor speed application

Abstract

Proportional-integral (PI) controller is still a widely used closed-loop controller in industrial application due to its simplicity and its ability to produce good performance. PI controllers can eliminate errors or disturbance in a system but are subjected to oscillation in their response, large overshoot, and prolonged settling time due to the coupled tuning-gains. Such unfavorable responses is due to what is known as the windup phenomenon, which can lead to system instability. Windup occur when a control system operates in a non-linear region when the controller output exceeded the limit of the system actuator. The system is unable to accurately determine the error within the system and supply necessary corrections within the control when the system enters into this saturated state. Windup can cause physical degradation leading to damages to the system that can lead to system malfunction. Various anti-windup techniques have been proposed as a means to overcome windup. Most of these techniques have coupled tuning gain similar to conventional PI controllers. A robust controller with decoupled tuning gain was proposed. The way this controller response to perturbation was found to produce minimal overshoot. This research explore the theoretical development and study of anti-windup PI controllers with semi- decoupled tuning gain (SDTG) capable of minimizing the effect of windup phenomenon. Scilab/Scicoslab version 4.4.1 was used to perform hardware simulation for the performance comparison of speed control between the proposed SDTG controller and the conventional PI controller. This research contributes to the body of knowledge by proposing a potential alternative controller in the industrial motor application with zero overshoot, fast rise and settling time as compared to the conventional PI controller.