working principle
The starting and operation of a permanent magnet synchronous motor are formed by the interaction of the magnetic fields generated by the stator winding, rotor squirrel cage winding, and permanent magnet. When the motor is stationary, a three-phase symmetrical current is applied to the stator winding, generating a stator rotating magnetic field. The stator rotating magnetic field generates a current in the cage winding relative to the rotor rotation, forming a rotor rotating magnetic field. The asynchronous torque generated by the interaction between the stator rotating magnetic field and the rotor rotating magnetic field accelerates the rotor from stationary to rotating. During this process, the rotor permanent magnetic field and the stator rotating magnetic field have different rotational speeds, resulting in alternating torque. When the rotor accelerates to a speed close to the synchronous speed, the speed of the rotor permanent magnetic field and the stator rotating magnetic field are almost equal. The speed of the stator rotating magnetic field is slightly higher than that of the rotor permanent magnetic field, and their interaction generates torque to pull the rotor into synchronous operation. In synchronous operation, no current is generated in the rotor winding. At this time, only the permanent magnet on the rotor generates a magnetic field, which interacts with the rotating magnetic field of the stator to generate driving torque. From this, it can be seen that permanent magnet synchronous motors are started by the asynchronous torque of the rotor winding. After the start-up is completed, the rotor winding no longer functions, and the magnetic field generated by the permanent magnet and stator winding interacts to generate driving torque
Motor drawings