Differences between mainstream new energy vehicle drive motors
The driving motors of new energy vehicles mainly include three types: permanent magnet synchronous, alternating current asynchronous and switched magnetic resistance. Due to their different characteristics, each has its own application.
Rare earth permanent magnet synchronous motor
According to the principle, the volume can be small, the quality is light, the power density is high, the reliability is high, the speed regulation precision is high, and the response speed is fast. Due to the high power density of the permanent magnet synchronous motor, the working efficiency is up to 97%, which can The vehicle outputs the maximum power and acceleration, which is mainly used in new energy passenger cars with the highest energy-volume ratio requirements.
The disadvantage is that the maximum power is lower and the cost is higher. AC asynchronous motors are low in price and reliable in operation; however, their low power density, complex control, and small speed range are inherent limitations. The price advantage makes it more widely used in new energy buses.
Induction (asynchronous) motor
Can endure large changes in working temperature. On the contrary, a large temperature change will damage the permanent magnet motor. The output torque of the induction motor can be neglected in a wide range. It does not need a heat-dissipating mechanism and is light in weight. It is similar in size to watermelon and weighs 52 kilograms. The speed range can reach 0-12000 rpm, so there is no need to install extra gears. Therefore, the weight of its body has a great advantage in new energy vehicles.
The disadvantage is that the rotor rotation speed is difficult to control, the energy consumption is large, the power factor is lagging, the structure is complex, and the induction (asynchronous) motor is used, and the control system has high technical requirements and high manufacturing cost.
Switched reluctance motor
The price is low, the circuit is simple and reliable, and the speed regulation range is wide; but the vibration, the hum, the control system is complicated, and the DC power source generates a large pulse current. For large passenger cars, BYD electric cars.
Among them, Japanese and Korean cars currently use permanent magnet motors, the speed range and efficiency are relatively high, but the use of expensive system permanent magnet material NdFeB is required; European and American cars use AC induction motors, mainly for rare earths. The lack of resources and the reduction of motor cost are mainly due to the small speed range and low efficiency, which requires higher performance governors to match performance.
