Dual Error Correction Extended State Observer-Based ADRC for PMSM Speed Control

In the speed control system based on linear ESO, poles and zeros exhibit inherent coupling characteristics. The conventional pole placement method typically neglects the impact of zero placement on observer performance, thereby diminishing the contribution of zeros to disturbance suppression and restricts the potential for further performance improvement. To overcome this limitation, this paper proposes a novel ESO structure by simultaneously incorporating measured position and speed states. Specifically, the ESO error correction term is optimized as a weighted sum of the position and speed estimation errors, which introduces an additional degree of freedom for the independent configuration of zeros and poles. The proposed method expands the tuning flexibility of linear ESO, reveals the influence of zero placement on the dynamic and steady-state performance as well as the stability margins and enhances the disturbance suppression performance through the independent zeros configuration. Finally, comparative experimental results confirm that the proposed dual-error-correction ESO-based speed controller exhibits superior disturbance rejection performance compared with the conventional methods under the same pole placement conditions.