Permanent magnet synchronous motor (PMSM) has the advantages of simple structure, small size, high efficiency and high power factor. The permanent magnet synchronous motor has gained achievements in medium and low voltage motors in metallurgy industry (iron making plant and sintering plant, etc.), ceramics industry (ball mill), rubber industry (internal mixer), oil industry (oil pumping unit), textile industry (double twister, spinning frame), etc., and gradually accumulated design and operation experience.

According to the permanent magnet structure, it is classified as surface permanent magnet synchronous motor (SPMSM) and built-in permanent magnet synchronous motor (IPMSM). According to the induced EMF waveform of stator winding, it is classified into sine wave permanent magnet synchronous motor and brushless permanent magnet DC motor. With the application market of motor products gradually shifting to the high-end market, the development of the high-end market will also put forward higher requirements for the performance of motor products.

Permanent magnet synchronous motor also has the advantages of high starting torque, short starting time and high overload capacity. It can reduce the installed capacity of equipment driven motor according to actual shaft power, save energy and reduce investment in fixed assets. The permanent magnet synchronous motor is easy to control, the speed is constant, does not change with the load fluctuation and voltage fluctuation, and only depends on the frequency. The operation is stable and reliable. Due to strict synchronization of rotating speed and good dynamic response performance, it is suitable for frequency conversion control.