AC asynchronous motor structure
In the field of passenger cars, the current application is mainly divided into induction (asynchronous) motors and permanent magnet (synchronous) motors. The main representative of the former is Tesla, while the latter is more mainstream, BMW and most domestic electric vehicle manufacturers. Have applied. What is the difference between the two?
The permanent magnet motor is a synchronous motor. The rotor uses permanent magnets, and the stator generates electromagnetic torque to push the magnetic field of the rotor to rotate around the axis, and the magnetic fields of the stator and the rotor are synchronized. The induction motor is an asynchronous motor, which is an AC motor in which a rotating magnetic field formed by a stator winding interacts with a magnetic field of an induced current in a rotor winding to generate an electromagnetic torque to drive the rotation of the rotor.
In the field of commercial vehicles, the use of switched reluctance motors is also very extensive, and its development prospects are also optimistic. The main advantage is that it does not require the use of permanent magnet materials, and there is no dependence on rare earths, even the common copper coils of motors are not used. The cost can be controlled to be relatively low.
Switched reluctance motors have two basic characteristics:
1. Switching, the motor must work in a continuous switching mode.
2. Magnetoresistive, it is a true reluctance motor. The stator and rotor have a variable reluctance magnetic circuit. More specifically, it is a doubly salient motor.
In terms of performance, the speed of the switched reluctance motor is very flexible, not only by changing the voltage, but also by changing the on and off angles, and having a good speed range and capability. Torque density and efficiency can also be close to the level of permanent magnet synchronous motor, stronger than induction motor.
However, the main disadvantage of switched reluctance motors is that the torque ripple is still large, and the vibration noise is larger than other motors. For passenger cars, this problem is obviously unacceptable, so it has not been used on a large scale for the time being.
