Improved Disturbance Rejection and Noise Suppression Properties for PMSM Speed Control Systems Using Different Order Fast Finite-Time Extended State Observers

The second-order typical fast finite-time extended state observer (FFESO), third-order generalized FESO, and third-order augmented FFESO are adopted to directly estimate the motor speed and lumped disturbance, thereby enhancing the disturbance rejection and noise suppression properties of permanent magnet synchronous motor (PMSM) speed control systems. Although conventional linear extended state observer (ESO) has been proven to improve the anti-disturbance and robustness of motor speed control system, its estimation error can only converge asymptotically to an infinite region. In this brief, different speed control algorithms combining proportional control with different types of FFESOs are proposed. By introducing nonlinear terms into conventional ESO, the estimation accuracy of the proposed FFESOs can be greatly enhanced. Meanwhile, experimental results show a clearer analysis of the characteristics of FFESOs with different structures and orders.