First, the characteristics of permanent magnet synchronous motor Permanent magnet synchronous motor simple structure, small size, light weight, low loss, high efficiency, DC motor, compared with DC motor, it does have the disadvantages of DC motor commutator brush. Compared with asynchronous motor, because it does need reactive excitation current, it has high efficiency, high power factor, large torque inertia ratio, reduced stator current stator resistance loss, the rotor parameters can be measured the control performance is good. However, compared with asynchronous motors, it also has disadvantages such as high cost difficulty in starting. Compared with the ordinary synchronous motor, it saves the excitation device, simplifies the structure improves the efficiency. PMSM vector control system can achieve high precision, high dynamic performance, wide range of speed control positioning control, so the PMSM vector control system has attracted extensive attention scholars at home abroad.

China is a country rich in permanent magnet materials, especially rare earth permanent magnet materials Ndfeb resources are very rich in our country, rare earth ore reserves are about 4 times the sum of other countries in the world, known as the "rare earth kingdom". The scientific research level of rare earth permanent magnet materials rare earth permanent magnet motors has reached the international advanced level. Therefore, for our country, permanent magnet synchronous motor has a good application prospect. The geometry of the rotor magnetic steel of the permanent magnet synchronous motor is different, so that the distribution of the rotor magnetic field in space can be divided into sine wave trapezoidal wave. Therefore, when the rotor rotates, the back electromotive force waveform generated on the stator also has two kinds: one is sine wave; The other is trapezoidal wave. In this way, the two synchronous motors are different in principle, model control method. In order to distinguish the AC speed regulation system of permanent magnet synchronous motor composed of them, the speed regulation system composed of sine wave permanent magnet synchronous motor is called sinusoidal permanent magnet synchronous motor (PMSM) speed regulation system.