The first choice for car companies' power systems-permanent magnet synchronous motors

2021-11-03 13:23:09 jact_elec

The first choice for car companies' power systems-permanent magnet synchronous motors

Generally, to understand the power performance of a car model, we must first know what kind of engine the car is equipped with, because the engine is the heart of the entire car. So for an electric car, its heart is the drive motor. When we look at the information related to the power system of most electric vehicles, there is a term that appears very frequently, that is, the permanent magnet synchronous motor.

Is it now that new energy passenger cars only use permanent magnet synchronous motors? In fact, some mid-to-high-end pure electric vehicles will choose to use AC asynchronous motors, such as Tesla and Weilai.

In addition, Audi e-tron and Mercedes-Benz EQC also install two AC asynchronous motors on the front and rear axles.

Compared with the permanent magnet synchronous motors used in domestic mainstream electric vehicles, will the asynchronous motors used in the more expensive mid-to-high-end electric vehicles be more advanced?

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What is the difference between the two types, which is better?

The working principle of the motor is that the energized coil will receive force in the changing magnetic field, and through the interaction of the two magnetic fields, the electromagnetic torque is converted into kinetic energy to drive the car. Here, the different ways of generating the magnetic field form the AC asynchronous motor and the permanent magnet synchronous motor.

The biggest advantage of permanent magnet synchronous motors is that they have very high power density and torque density, and lower energy consumption. Under the same weight and volume, the permanent magnet synchronous motor can output higher power and torque.

In the same way, under the same power and torque, the use of permanent magnet synchronous motors can obtain the smallest weight and volume, leaving enough space and quality for another extremely important component "power battery". The disadvantage is that the price of permanent magnet materials required by the motor remains high, which increases the manufacturing cost of the motor and even the entire vehicle.

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The advantages and disadvantages of AC asynchronous motors are just opposite to those of permanent magnet synchronous motors. The advantage of the former is that the motor does not require expensive permanent magnet materials, so the cost is lower, and the process is simple, reliable in operation, easy to maintain, and can be used in complex working environments.

Medium work, also has a relatively strong ability to adapt to large changes in the surrounding operating temperature. The disadvantage is that under the same power and torque, the volume and weight of the asynchronous motor are much larger than that of the permanent magnet synchronous motor, and the energy consumption is relatively higher.

The difference between the two types of motors, permanent magnet synchronous motors and AC asynchronous motors, is quite similar to the naturally aspirated engines and turbocharged engines of traditional fuel vehicles.

Each has its own advantages and disadvantages. However, judging from the current development momentum, permanent magnet synchronous motors are likely to become the first choice for more car companies' power systems in the future.