This paper describes in detail the magnetization process of a synchronous motor, constructed with High Temperature Superconducting (HTS) elements on the rotor. The Pulse Field Magnetization (PFM) method is considered to magnetize the HTS rotor as a four-pole trapped flux magnet. A 2D model is built for the magnetization process. During the machine operation, intolerable torque ripples occur, which are mainly caused by the irregular field distribution from the magnetized HTS rotor. In order to suppress the large torque ripples, an iterative learning control method is used in addition to the traditional field-oriented control method.
Jiang, Y., Pei, R., Xian, W., Hong, Z., Yuan, W., Marchant, R., & Coombs, T. A. (2009). Magnetization process of an HTS motor and the torque ripple suppression. IEEE Transactions on Applied Superconductivity, 19(3), 1644-1647. https://doi.org/10.1109/tasc.2009.2018417