Development of a PM linear motor for driving HTS maglev vehicle

The phenomenon that a permanent magnet (PM) over a high temperature superconductor (HTS) bulk can produce strong levitation force with self-stabilizing feature has attracted strong interest of application in maglev transportation systems, in which a linear motion drive is an obvious advantage. This paper presents the development of a PM linear synchronous motor drive for a small-scale prototype vehicle which is levitated by PM-HTS bulks. Magnetic field finite element analyses are conducted to compute accurately the key motor parameters such as winding flux, back electromotive force (emf), inductance and cogging force. The steady state characteristic of the motor is predicted by using the classic phasor voltage equation, which can provide a reasonable result if the fundamental components of the applied voltage, back emf and current are dominant. A Matlab/Simulink-based model, capable of considering the dependence of key parameters on the mover position, is built to predict effectively the motor´s dynamic performance under a brushless DC (BLDC) control scheme. The simulated results show that the developed linear motor can drive the HTS maglev vehicle prototype at the desired speed.