Study of anti‐windup pi controllers with different coupling–decoupling tuning gains in motor speed

Abstract

Proportional‐integral (PI) controller is still a widely used closed‐loop controller in industrial applications due to its simplicity. PI controllers experience difficulty in having both non‐overshoot with short rise time. Such unfavorable response is due to its coupled tuning‐gains and the integral windup, which eventually leads to system instability. Various anti‐windup techniques have been proposed. However, similar to the conventional PI controllers, most of these techniques have coupled proportional and integral tuning gains that affect one another. The controllers contain adaptive switching between the conventional and its designated integral control depending on the saturation state. This paper proposes a robust non‐switching anti‐windup PI controller with semi‐decoupling tuning gain. Speed control simulation and experimental testing are conducted to investigate the impact of the various tuning gain dependency. The proposed controller shows a fast response with no overshoot as compared to the conventional and other non‐switching anti‐windup PI controllers with coupling and decoupling tuning gain at certain loading conditions.

Introducing concepts of passivity‐based control in anti‐windup algorithms

“…It is well known that proportional–integral–derivative (PID) controls cover a big part of industrial applications [1, 2], with most of the developed controls designed not taking into account the constraints of the system [3]. Nowadays, the prestabilizing controller design is known as the first task when considering (the second task) anti‐windup schemes [3, 4].…”

“…Besides its "universally stabilizing properties" [18], PBC explicitly obtains the Lyapunov function of the system contributing to the understanding of the controlled process from a different point of view than classical time responses. According to FIGURE 1 PID control and actuator constraints the authors knowledge, PBC has not contributed to the windup problem yet; hence, considering the importance of PID control around the industrial world [1,2], in this work, PBC is introduced as a novel tool in AW schemes for PID controllers.…”

Stabilization of a chaotic oscillator via a class of integral controllers under input saturation

“…The saturation of a controller diminishes the anticipated closed-loop performance of the system's dynamics and, in extreme condition, may lead to closed-loop instability 29 . Now, the analysis of the saturation of control has been performed by anti-windup designs, where the applications to linear systems and PI controllers have been dominant in the open literature [30][31][32][33] . PI controllers are widely employed in a vast majority of linear and nonlinear systems, and the proportional term acts to stabilize the dynamic behavior of the system close to the required reference or set point, but high proportional gain values are needed to diminish the offset 34 , i.e., the difference in the current value of the controlled variable and the set point, making the control action very sensible.…”