At present, the types of motors used in pure electric passenger cars produced in China mainly include permanent magnet synchronous motors, AC asynchronous motors, hybrid excitation synchronous motors, and brushless DC motors. This paper is divided into two parts, which introduces the market status and trend of the above various motors in the field of pure electric passenger vehicles, and the comparison of motor performance advantages.
The current status and trend of the main motor market of pure electric passenger cars
According to the statistics of China Association of Automobile Manufacturers, from January to June 2016, the production and sales of pure electric vehicles in China reached 134,000 and 126,000 respectively, an increase of 160.8% and 161.6% respectively over the same period of the previous year.
In the first half of 2016, China produced a total of about 70,000 pure electric passenger vehicles, of which the installed capacity of permanent magnet synchronous motors was about 46,000, accounting for about 65.7%; the installed capacity of AC asynchronous motors was about 23,000, accounting for about 63,000. 32.9%; the installed capacity of hybrid excitation synchronous motor is about 760, accounting for about 1.1%; the installed capacity of brushless DC motor is less, accounting for about 0.3%.
In 2015, the output of China's pure electric passenger vehicles was about 150,000, of which the output in the first half of the year was about 39,000. Hybrid excitation synchronous motors have an installed capacity of about 200 vehicles in the whole year, and the installed capacity in the first half of the year is less than 10; the installed capacity of permanent magnet synchronous motors is 68,700 in the whole year and 17,300 in the first half of the year; the annual installed capacity of AC asynchronous motors is 59,000, and the first half of the year is 13,700. Brushless DC has 22,360 vehicles in the whole year and about 7,900 in the first half of the year. The share of various types of motors in the first half of 2015 and the whole year.
By comparing we can draw the following conclusions:
1. Permanent magnet synchronous motor is the first choice motor for electric passenger cars, and the market share is gradually increasing;
2. The market share of AC asynchronous motors is relatively stable. It is one of the mainstream electric passenger car motors, and its market share has gradually decreased with the market share of permanent magnet synchronous motors and other types of motors. However, it will remain in the mainstream for a long period of time;
3. The market share of brushless DC motors is dropping sharply. It was 20.3% in the first half of 2015, and it was reduced to 14.8% in the whole year. By the first half of 2016, the market share was less than 1%. The author believes that this is a dangerous signal, reflecting that pure electric passenger car manufacturers may exclude brushless DC motors in the future;
4. Hybrid excitation synchronous motors are increasingly favored by pure electric passenger car manufacturers, and the market share is gradually increasing, from 0.03% in the first half of 2015 to 0.1% in the whole year, and then to the first half of this year. 1.1%. Through comparative analysis, the author believes that the market share of hybrid excitation synchronous motors will maintain a small and steady growth, but the timing of the explosion will take a long time. Companies with technological advantages in this area may wish to increase R&D productivity.
Analysis of several motor performance and advantages
1, hybrid excitation motor
According to the relevant academic literature, the hybrid excitation synchronous machine (HESM) integrates the advantages of easy excitation and magnetic adjustment of the electric excitation synchronous motor, high efficiency of the permanent magnet synchronous motor, and large torque/mass ratio. It overcomes the shortcomings of magnetic field adjustment of permanent magnet synchronous motor.
Compared with permanent magnet motors, hybrid excitation motors have the ability to adjust the air gap magnetic field; they have a smaller armature reactive reactance than electric excitation synchronous motors. The hybrid excitation motor can not only inherit the many characteristics of the permanent magnet motor, but also has the advantages of smooth and adjustable air gap magnetic field of the electric excitation motor. Used as an electric motor, it is suitable for energy-saving driving, and its wide speed regulation characteristics can be applied in high-demand occasions such as electric vehicles and weapon equipment servo drives.
2, permanent magnet synchronous motor
Permanent magnet synchronous motor is the most popular type of motor in the current electric passenger car market.
Related literatures show that the permanent magnet synchronous motor has the characteristics of high power efficiency, low heat generation, simple structure of the motor cooling system, small volume and low noise. The system adopts a fully enclosed structure, which is free from lubricating oil and maintenance-free, and has a large overload current and high reliability. This type of motor is beneficial to improve the dynamic performance of the vehicle. The disadvantage is that the motor structure is complicated and the cost is high.
3, AC asynchronous motor
The motor has high efficiency, high reliability, long service life and low operating cost.
4, brushless DC motor
This type of motor is small in size, high in efficiency, and low in failure rate.
The disadvantage is that it is easy to generate resonance, and a sound of squeaking occurs on an electric vehicle, and the cost is high.
