Robust Control Design for Multi-Input Multi-Output Permanent Magnet Synchronous Motor Systems Under Load Torque Disturbances

This paper presents a robust control approach for permanent magnet synchronous motors. The nonlinear model of these motors includes two voltage inputs in d-q coordinates and two outputs: speed and current in the d direction. Load torque is viewed as a perturbation. To address this, we employ a combined nonlinear multi-input-multi-output control method based on an observer. The observer estimates the uncertain load torque, and the nonlinear MIMO controller designs the control input vector accordingly. The observer, developed using the sliding mode method, estimates both the load torque and its derivative, which are essential for the control system. The controller design also utilizes MIMO sliding mode control. The stability of the feedback-controlled system, comprising the MIMO controller, observer, and motor dynamics, is proven using the Lyapunov method. The proposed hybrid method offers advantages such as nonlinearity handling, robustness to uncertainties, and vector control design. These features are shown both analytically and via computer simulations.