Sensorless Control with Sliding-Mode Observer for Superconducting Linear Motors

In the application of the ultra-high-speed low-vacuum tube maglev transportation system, the superconducting linear motors are utilized for propulsion. The cross-inductive wire which is used to obtain position and speed information needs to be installed along the line. The cost of the hardware and maintenance is expensive. These limitations greatly promote the sensorless control of the superconducting linear motors, especially in high speed region. In this paper, one sensorless control strategy based on sliding-mode observer is proposed for superconducting linear motors, which achieves good performance in medium to high speed region and maintains stable during transient procedure. The control strategy under power supply fed at two ends is also discussed. The effectiveness of the proposed method is demonstrated by simulation studies.