SDRE-Based Near Optimal Control System Design for PM Synchronous Motor

Abstract

This paper presents a nonlinear optimal speed controller based on a state-dependent Riccati equation (SDRE) for permanent magnet synchronous motor (PMSM). An SDREbased near optimal load torque observer is also proposed to provide the load torque information for the controller. In both designs, the stability is analytically proven and Taylor series method is used to find an approximate solution because the SDRE cannot be directly solved. The SDRE-based optimal controller and observer can ensure better control performance such as no overshoot and fast transient response in speed tracking than the linear conventional controllers such as LQ regulator and PI controller even under the variations of the model parameters and load torque. The proposed SDRE-based control strategy is implemented on a PMSM testbed using TMS320F28335 DSP. The simulation and experimental results are given to prove the feasibility of the proposed control scheme