Sensorless Adaptive PI Control of High-Power Propulsion PMSM Based on Sliding-mode Extremum Seeking Algorithm

This paper proposes a multivariable-sliding-mode extremum-seeking (MSES)-based adaptive PI method for sensorless speed control of high-power propulsion permanent magnet synchronous motor (PMSM) applications. Unlike the offline-tuning PI controllers, the proposed controller incorporates adaptive tuning laws that dynamically adjust the control gains in real-time using the gradient descent method. Using a speed feedback error term and a suitable sliding surface, the MSES tunes the PI gains during operation with a low computational load. Real-time tuning of the PI gains can reduce the system sensitivity against the variation of both the motor parameters and the load torque disturbances, and therefore, a satisfying tracking performance can be achieved. This method is easy to implement on a medium-performance micro controller unit (MCU). In order to verify the performance of the proposed control method, a simulation study is conducted using MATLAB/Simulink software, which shows that the proposed method has relatively high accuracy as well as satisfactory performance in terms of robustness against load torque perturbation and independence of parametric variations.