Sensorless control for high-speed linear synchronous motor based on a deadbeat predictive observer

Sensorless control technology shows promising application prospects in electromagnetic sled systems due to its advantages of high reliability and cost-effectiveness. However, electromagnetic sled systems present special operating conditions including high power, short-duration operation, reciprocating motion, time-varying parameters, and strong nonlinear disturbances, imposing higher demands on the dynamic response and robustness of observers. To address this issue, this paper proposes a deadbeat predictive back-electromotive force (back-EMF) observer. Based on the deadbeat predictive principle, the method ensures that the estimated current tracks the actual value within one control cycle, significantly improving the dynamic response and accuracy of the observer, Furthermore, an enhanced phase-locked loop (PLL) structure is designed to accurately extract the position information of the motor’s reciprocating motion. A detailed theoretical analysis of the method’s stability and parameter robustness is provided. Simulations and experiments conducted on a 4 MW electromagnetic propulsion test platform validate the effectiveness of the proposed model.