Steady-State Integral Proportional Integral Controller for PI Motor Speed Controllers

Abstract

The output of the controller is said to exceed the input limits of the plant being controlled when a control system operates in a non-linear region. This process is called the windup phenomenon. The windup phenomenon is not preferable in the control system because it leads to performance degradation, such as overshoot and system instability. Many anti-windup strategies involve switching, where the integral component differently operates between the linear and the non-linear states. The range of state for the non-overshoot performance is better illustrated by the boundary integral error plane than the proportional-integral (PI) plane in windup inspection. This study proposes a PI controller with a separate closed-loop integral controller and reference value set with respect to the input command and external torque. The PI controller is compared with existing conventional proportional integral, conditional integration, tracking back calculation, and integral state prediction schemes by using ScicosLab simulations. The controller is also experimentally verified on a direct current motor under no-load and loading conditions. The proposed controller shows a promising potential with its ability to eliminate overshoot with short settling time using the decoupling mode in both conditions.

Integration of Derivative Control on SIPIC in Motor Speed Control

“…SIPIC has shown the tuning gain decoupling effect which results in better motor speed control performance as compared to the conventional PI and anti‐windup PI controllers . Unlike the current anti‐windup PI methods, SIPIC does not require switching between two different integral control operations, and hence free from any instability related to switching . SIPIC controlled system is stable regardless of the k p and k i values.…”

“…This constrains the choice of tuning parameter to attain desired control performance. In the year 2015, a new anti‐windup PI controller with k p and k i decoupling feature, the Steady‐State Integral Proportional‐Integral Controller (SIPIC) was developed from a control template . SIPIC utilises the steady state integral seeking approach and is able to reduce the dependency among tuning parameters.…”

“…By formulating the required control design parameter in the control template, the tuning parameters are separated into distinct poles in the dynamic equation model of the system . SIPIC has shown better motor speed control performance as compared to the conventional anti‐windup controllers .…”

Evaluation of SIPIC01 and SIPIC02 on Motor Speed Control

“…According to the characteristic of the term in the general Equation (1) stated in section 3, Hoo et al proposed a structure of the controller as shown in Equation (3) where A 1 can be any constant [8], [9].…”

“…The error equation of SIPIC01 (7) can be derived through the substitution of Equation (5) into Equation (6). Equation (8) corresponds to the damping ratio of SIPIC01, which is formed from the denominator of Equation (7) by comparing with the general characteristic equation, 2 + 2 + 2 , where and are the damping ratio and natural frequency respectively.…”