PMSM Speed Control Using an Enhanced State Feedback Controller and Linear Quadratic Regulator for Effective Drive System
Crescent Onyebuchi Omeje *
Department of Electrical/Electronic Engineering, University of Port Harcourt, Choba, Port Harcourt, Nigeria.
Chizindu Stanley Esobinenwu
Department of Electrical/Electronic Engineering, University of Port Harcourt, Choba, Port Harcourt, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
This paper introduced an effective method for regulating and controlling the speed of PMSMs (permanent magnet synchronous motors) by linearizing the non-linear and time-varying equations that model the PMSM dynamics. This method was achieved by utilizing an improved state feedback controller along with a linear quadratic regulator (LQR) to determine an optimal performance index. In order to assess external load torque disturbances in the system, a disturbance observer (DO) method was employed. Additionally, a sliding mode observer was utilized in conjunction with the disturbance observer to control motor speed. Simulations were conducted to compare the state feedback controller with a conventional PI- controller. The results showed that the state feedback controller achieved a robust as well as improved speed and torque dynamic performance with a reduced steady-state error percentage of 24.17% and 23.51%, as compared to 38.0% and 38.37% obtained using a PI-controller. The derived state feedback matrix (K), based on Ackerman’s rule, demonstrated that the entire system is controllable and that the performance index is marginally stable. All simulations were achieved in MATLAB/SIMULINK 2021 version.
Keywords: Permanent magnet synchronous motor, mathematical modeling, Linear Quadratic Regulator (LQR), Disturbance Observer (DO), Sliding-Mode-Observer (SMO), PI-controller, State-Feedback Controller (SFC), simulation