The working principle of AC permanent magnet synchronous motor
The self-controlled AC-DC voltage motor control mode adopted by the system is composed of a rectifier bridge, a three-phase inverter circuit, a control circuit, a three-phase AC permanent magnet motor and a position sensor, and its structural principle is shown in FIG. 2 . In Fig. 2, after the 50HZ mains is rectified, the three-phase inverter supplies power to the three-phase winding of the motor, and the rotating magnetic field synthesized by the three-phase symmetrical current interacts with the magnetic field generated by the permanent magnet of the rotor to generate torque. Drag the rotor synchronously, and read the position of the rotor magnet through the position sensor, change the electrical signal to control the inverter power device switch, adjust the current frequency and phase, and maintain the stable positional relationship between the stator and rotor magnetic potential to produce a constant The torque, the amount of current in the stator winding is determined by the load. The frequency and phase of the three-phase current in the stator winding change with the change of the rotor position, so that the three-phase current is combined into a rotating magnetic field synchronized with the rotor, and the commutation of the three-phase current is realized by the switching change of the inverter circuit composed of the power electronic device. Instead of a mechanical commutator.
The sinusoidal permanent magnet synchronous motor is a self-controlled motor, except that the stator back electromotive force and current waveform of the motor are both sinusoidal and remain in phase, which can obtain the same torque characteristics as the AC motor, and realize the constant torque speed regulation characteristics. . The position servo system realizes the position servo function by a sine wave permanent magnet synchronous motor.
