Electromagnetic Analysis of a HTS Linear-Rotary Permanent Magnet Actuator

In this paper, a novel linear-rotary permanent magnet actuator (LRPMA) is proposed with high-temperature superconducting (HTS) field winding imbedded in the stator. In order to show the merits of the HTS LRPMA, a same structure without HTS field windings and one with permanent magnet mounted on the surface of the mover with same magnetization direction are taken as the comparison. The electromagnetic characteristic and harmonic analysis of the three topologies are analyzed using finite element method, including flux density, back electromotive force, cogging torque and cogging force, torque, and thrust. The air-gap flux density can be easily controlled by adjusting dc current in the HTS field winding. Compared with the other two structures, the torque density of the proposed LRPMA can be easily increased. The computed results show that the performance of the HTS LRPMA, such as the torque density, can be greatly improved.