Working principle of permanent magnet synchronous motor

Permanent magnet synchronous motor is a DC motor, its working principle is based on the law of electromagnetic induction and the principle of electrodynamics. This motor has the advantages of high efficiency, high power density and high precision, and is suitable for applications that require high precision and high efficiency.

Permanent magnet synchronous motors use permanent magnets to provide excitation, which makes the motor structure simpler, reduces processing and assembly costs, and eliminates slip rings and brushes that are prone to problems, thereby improving the reliability of motor operation. Because no excitation current is required and there is no excitation loss, the efficiency and power density of the motor are improved.

The permanent magnet synchronous motor is composed of stator, rotor and end cover. The stator is basically the same as the ordinary induction motor, and adopts a laminated structure to reduce the iron loss of the motor during operation. The rotor can be made solid or laminated. The armature winding can be concentrated full-pitch winding, distributed short-pitch winding and unconventional winding.

The structure of a permanent magnet synchronous motor is different from that of a traditional asynchronous motor. Its rotor is equipped with a group of strong magnets, such as permanent magnets or neodymium iron boron magnets, which can generate a constant magnetic field. The stator is arranged with several groups of windings. A three-phase current is passed through the windings on the stator to generate a rotating magnetic field, which interacts with the constant magnetic field on the rotor, thereby causing the rotor to rotate.

The working principle of permanent magnet synchronous motor can be explained in two aspects:

Principle of electromagnetic induction

When the three-phase current passes through the stator winding, it generates a rotating magnetic field, which interacts with the constant magnetic field on the rotor to generate an electromotive force to drive the motor to rotate. When the motor is running, the current and magnetic field on the stator are rotating, while the magnetic field on the rotor is stationary, so the motor is also called a "synchronous motor".

Principle of magnetic field

The strong magnets on the rotor can generate a constant magnetic field. When current is passed through the stator winding, the generated rotating magnetic field interacts with the rotor magnetic field to form a torque to drive the motor to rotate. Since the rotor magnetic field is fixed, the speed is proportional to the frequency of the input current, and the torque is proportional to the magnitude of the input current.

In short, the working principle of the permanent magnet synchronous motor is to use the rotating magnetic field generated by the stator winding to interact with the constant magnetic field on the rotor to drive the motor to rotate. At the same time, the speed and torque of the permanent magnet synchronous motor can be precisely adjusted by controlling the frequency and size of the input current.