(1) High power factor and high efficiency;

(2) Simple structure and reliable operation;

(3) Small size, light weight and small loss.

Compared with other kinds of motors

(1) Compared with DC motor, there is no commutator and brush of DC motor;

(2) Compared with induction motor, it has high efficiency, high power factor, large moment inertia ratio, less stator current and resistance loss, measurable rotor parameters and good control performance due to no reactive excitation current;

(3) Compared with the common synchronous motor, it omits the excitation device, simplifies the structure, improves the efficiency, and can achieve the high performance (such as ultra-high efficiency, ultra-high speed, ultra-high response speed) that the traditional electric excitation motor can not match;

(4) Compared with switched reluctance motor (SR), it does not have the problem of large torque ripple at low speed, and has already realized stable operation at low speed, so it is suitable for fast and high precision control occasions.

(5) Compared with BLDCM, it is more competitive in high precision servo drive.


The basic structure of PMSM is composed of stator and rotor.

The stator of PMSM is similar to the traditional motor, but its slot number is often different from the traditional motor after strict calculation.

Permanent magnet synchronous servo motor has a unique rotor structure, which is equipped with permanent magnet poles.

According to the different installation methods of permanent magnet, it can be divided into convex type, embedded type (or surface type, built-in type) and other different rotor structures.

Permanent magnet synchronous motor (PMSM) is a kind of AC permanent magnet servo motor.

In the field of medium and small capacity high-precision transmission, permanent magnet synchronous servo motor is widely used to generate magnetic field by adding permanent magnet on the rotor. Due to the inherent characteristics of permanent magnetic materials, it can establish a strong permanent magnetic field in the surrounding space without additional energy. This can not only simplify the motor structure, but also save energy.