The permanent magnet synchronous motor has the characteristics of simple structure, small volume, light weight, low loss and high efficiency. Compared with DC motor, it has no disadvantages such as commutator and brush of DC motor. Compared with the induction motor, because it does not require reactive excitation current, high efficiency, high power factor and torque inertia ratio, reducing the consumption of stator current and stator resistance, rotor parameters can be measured, and the control performance is good; but it is also compared with the induction motor, the disadvantages of high cost, difficult to start etc.. Compared with the common synchronous motor, it saves the excitation device, simplifies the structure and improves the efficiency. Permanent magnet synchronous motor vector control system can achieve high accuracy, high dynamic performance and wide range of speed control or location control. Therefore, permanent magnet synchronous motor vector control system has attracted wide attention of scholars at home and abroad. China is a country rich in permanent magnet materials, especially rare earth permanent magnet materials, NdFeB resources are very rich in China. The storage capacity of rare earth ore is about 4 times the total sum of other countries in the world. It is known as "Rare Earth Kingdom". The scientific research level of rare earth permanent magnetic material and rare earth permanent magnet motor has reached the international advanced level. Therefore, for our country, permanent magnet synchronous motor has a good application prospect.