Disturbance suppression for PMSM by a non‐linear composite controller based on two‐channel strategy

A non‐linear adaptive backstepping controller based on linear extend state observer (NABESO) is designed to track speed of PMSM. This study proposes a two‐channel strategy which is applied for the online elimination of the influence of unknown load torque and parameters disturbances. According to the strategy, an adaptive controller is designed to eliminate the load torque and parameters disturbance of the first channel, and a linear extended state observer is chosen in a feedforward method to observe the internal time‐varying parameters disturbance of the second channel as well as compensating the disturbances from the first channel. The proposed strategy can not only achieve online estimation of the load disturbance, but also suppress disturbances caused by the changes of all parameters, and to some extent, the negative transient response can also be avoided by abandoning traditional cascade control mode. Besides the functional advantages, the proposed controller is of pertinence and flexibility in parameters selection. Finally, the simulation and experimental results both display that the proposed strategy can effectively suppress the impact of internal and external disturbance on the PMSM control performance.