Uncertainty Compensation and Suppression of PMSM based on Extended State Observer

Xing Ren

Abstract: To address the issue of uncertainty factors such as parameter changes, load disturbances, unmodeled dynamics, and friction affecting the position tracking accuracy of PMSM servo systems, most existing advanced control methods only design disturbance suppression control laws for the speed loop in order to ensure the disturbance suppression capability of the closed-loop system. In order to further improve the disturbance suppression capability of the system, this paper proposes a control scheme that adopts disturbance suppression control law not only for the speed loop but also for the q-axis current loop. Considering the dynamic characteristics of q-axis current, the coupling between rotor speed and d-axis current, as well as the back electromotive force, are considered as concentrated disturbances in the q-axis current loop, and are estimated by introducing an extended state observer (ESO). It regards the aggregate disturbance of the system as a new system state, including the internal dynamics and external disturbances of the system. It can estimate both the state and the concentrated disturbance. Therefore, a composite control law consisting of proportional feedback and disturbance feedforward compensation was designed to control the q-axis current.

Submission Number: 198