Perhaps for historical reasons, the electric vehicle driving motor used by Tesla Company has always been a three-phase induction motor, that is, an asynchronous motor, which is an AC motor. Because the rotating magnetic field formed by the stator winding interacts with the magnetic field of the induced current in the rotor winding, electromagnetic torque is generated to drive the rotor to rotate.
Not only because of the historical situation, Tesla has made a breakthrough in asynchronous motor technology, and Tesla has invented and applied for many patents. In the past, the biggest defect of asynchronous motor was that the rotor speed was difficult to control, but with the development of modern semiconductor control technology, this problem has been solved.
Asynchronous motor has its own advantages, which can tolerate large changes in working temperature, and the output torque of induction motor can be adjusted in a wide range, with good efficiency and low cost in a high-speed range. However, asynchronous induction motor consumes more energy because of unilateral excitation, which requires more current to produce unit torque. Moreover, the power factor lags behind, the high efficiency area is narrow, and the stator has reactive excitation current, so the power is low (especially in the constant torque area), which further restricts the automobile performance.