Fast Response Sliding Mode Linear Speed Control of a Magnetic Screw Motor Based on Feedforward Compensation Strategy

The dynamic performance of the magnetic screw motor (MSM) drive system is influenced by the motor structure. In particular, when the motion direction of the mover changes, the MSM will stagnate for a while. Therefore, a sliding mode linear speed controller (SMLSC) is designed for the MSM linear speed drive system to enhance the dynamic performance of the system. Considering that the regulating function of the controller is limited, a novel feedforward compensation strategy based on the transmission ratio of the MSM is proposed to further shorten the stagnation time of the mover and improve the response speed of the system without affecting the system stability. The proposed compensation strategy can obtain the desired rotor angle speed and the desired
$q$
-axis current in advance when the given linear speed changes. Then, the desired values are compensated for the given rotor speed and the given
$q$
-axis current. Furthermore, the influence of the relative motion error caused by the change in transmission ratio on the feedforward compensation strategy is analyzed. The reliability and validity of the proposed method are verified through experiment results.