New energy vehicle drive motor technology

As one of the core three-electric systems of new energy vehicles, the motor is the core component of the vehicle just like the engine of a fuel vehicle. The component with the highest production cost of a new energy vehicle is the power battery, accounting for about 30%, while the motor accounts for 10%. At present, many manufacturers are producing and developing new energy vehicle motors. In this field, China's technology is still relatively advanced. Compared with fuel vehicle engines, it has more advantages, and there are many fewer technical barriers.

New energy vehicle drive motors are developing towards the goals of small size, light weight, high efficiency, better torque characteristics, long service life, high reliability, low noise and low price.

Comparison of the advantages and disadvantages of various new energy motors

At present, the classification of motors mainly includes four types: DC, AC induction, permanent magnet synchronous and switched reluctance. Permanent magnet synchronous motor is the mainstream type of motor due to its better performance. The price of the AC asynchronous motor is moderate, but the performance is slightly inferior, and it is used by some manufacturers in the United States and China. The main advantage of the switched reluctance motor lies in its lower price, but at the same time there are technical problems of noise and vibration. If these problems can be solved, the switched reluctance motor will have a large market.

At present, the drive motors suitable for new energy vehicles mainly include permanent magnet synchronous, AC asynchronous and switched reluctance. Because of their different characteristics, each has its application occasions.

The permanent magnet synchronous motor is small in size, light in weight, high in power density, high in reliability, high in speed regulation accuracy, and fast in response; but its maximum power is low and its cost is high. Since the permanent magnet synchronous motor has the highest power density, its working efficiency can reach up to 97%, and it can output the maximum power and acceleration for the vehicle. Therefore, it is mainly used in new energy passenger vehicles that require the highest energy volume ratio.

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 widely used in new energy buses.

Switched reluctance motors are low in price, simple and reliable in circuit, and wide in speed regulation range; however, they have large vibration and noise, complex control system, and will generate a large pulse current to the DC power supply, and are used in large passenger cars.

Motor development technology trends

In general, permanent magnet synchronous motors have distinct advantages over induction motors. However, the current cruising range of pure electric vehicles is bound to be an extremely important indicator, and the high efficiency of permanent magnet synchronous motors can better improve the cruising range. Moreover, the successful development of NdFeB permanent magnets with high heat resistance and high magnetic properties and the further development and improvement of power electronic components have further improved the development of rare earth permanent magnet synchronous motors. But as far as the current development trend is concerned, the permanent magnet synchronous motor seems to have a better prospect.

With the rapid development of new energy vehicle drive technology, many new structures or new concept motors have been put into research. Among them, the new permanent magnet brushless motor is one of the most promising motors at present, including hybrid excitation type, hub type, double stator type, memory type and magnetic gear compound type. In addition, amorphous motors have also begun to enter the field of new energy vehicles. As a new generation of high-performance motors, their own advantages will definitely play a huge role in promoting the development of the new energy vehicle industry.