Improved Adaptive Speed Observer of Permanent Magnet Linear Synchronous Motor With Transient Characteristics

To ensure accurate closed-loop control of the transient motor system, the eddy current position sensors are generally adopted for obtaining motor operation signals. However, the transient operating characteristics of the motor will degrade the accuracy and reliability of position sensors and even worse result in abnormal operation. To address these issues, one improved adaptive speed observer with high accuracy is proposed in this work, thus ensuring the safe and stable operation of the dual three-phase permanent magnet linear synchronous motor (DTP-PMLSM) under the aperiodic transient operation. In this improved observer, an observation model is constructed that considers the effect of stochastic noise, and the expectation of the observation error is derived. In addition, the minimization of the expectation is achieved via a linear quadratic regulator (LQR), which can get higher observation accuracy with a simplified method. Moreover, a speed adaptive law is designed, which can dynamically adjust to changes in the system. Comprehensive simulations and experiments based on a 4-kW prototype have fully demonstrated the effectiveness and the superiority of the improved observer.