The rapid progresses of astronomical and astrophysical researches call for high-resolution large astronomical optical telescopes to track the remote celestial bodies. It goes without saying that the mount drive control is the key technique which affects the telescope’s resolution and speed mostly. However, the ultra-lower speed and the giant

moment of inertia make the mount drive of the telescope very difficult to be controlled. In this paper, a permanent-magnet synchronous motor (PMSM) with saliency is suggested for the mount driving. As to the motor, a method is presented to drive the motor directly, which based on Space Vector Modulation of Vector-control (SVM-VC) and injecting high frequency (HF) signals to the stator windings. Conventional PMSM control methods like direct torque or friction control have many disadvantages at low or zero speed, such as the current and torque ripple which impair the drive performance. Unlike conventional methods, we can extract the rotor position information from the corresponding high frequency current response when HF signals are injected to the salient motor. The cost is heavily reduced for that the motor has no sensor or shaft. The main advantage of the proposed method is that the friction torque and the current ripple are very small. Simulation results show that the machine with saliency can work stable and the mount drive can realize nice tracking performance at ultra-lower speed.