What are the performance requirements for electric vehicle motors

In this era of increasing traffic flow, the main function of electric vehicle motors is to generate driving torque. As a power source for electric vehicles, what are the performance requirements of electric vehicle motors? Let’s take a look with the editor.

The car needs high torque at low speed or climbing, and low torque at high speed. The main requirements that the electric vehicle motor should meet can be summarized into the following 10 aspects:

1. High voltage

Within the allowable range, using a high voltage as much as possible can reduce the size of the motor and the size of the wire and other equipment, especially the cost of the inverter. The working voltage is increased from 274 V of THS to 500 V of THS B; under the condition of unchanged size, the maximum power is increased from 33 kW to 50 kW, and the maximum torque is increased from 350 N"m to 400ON"m. It can be seen that the application of high-voltage systems is extremely beneficial to the improvement of vehicle power performance

2. High speed

The speed of the induction motor used in electric vehicles can reach 8 000-12 000 r/min. The high-speed motor is small in size and light in weight, which is conducive to reducing the quality of equipment for loading.

3. Light weight and small size

The quality of the motor can be reduced by using an aluminum alloy casing, etc., and the materials of various control devices and cooling systems should also be made of light materials as much as possible. The electric vehicle drive motor requires high specific power (output power per unit mass of the motor) and high efficiency in a wide range of speed and torque to reduce vehicle weight and extend driving range; while industrial drives Electric motors are usually combined with power, efficiency and cost to optimize efficiency around the rated operating point

4. The motor should have a large starting torque and a wide range of speed regulation performance to meet the power and torque required for starting, accelerating, driving, decelerating, braking, etc. The electric motor should have an automatic speed regulation function to reduce the driver's manipulation intensity, improve the driving comfort, and be able to achieve the same control response as the accelerator pedal of an internal combustion engine vehicle

5. The electric vehicle drive motor needs to have an overload of 4 to 5 times to meet the requirements of short-term acceleration and maximum gradeability, while the industrial drive motor only requires 2 times of overload.

6. Electric vehicle drive motors should have high controllability, steady-state accuracy, and dynamic performance to meet the coordinated operation of multiple motors, while industrial drive motors are only required to meet a specific performance

7. The motor should have high efficiency, low loss, and can recover braking energy when the vehicle decelerates

8. The safety of the electrical system and the safety of the control system shall meet the relevant standards and regulations. The working voltage of various power battery packs and motors of electric vehicles can reach more than 300 V, so high-voltage protection equipment must be equipped to ensure safety

9. Able to work reliably under harsh conditions. The motor should have high reliability, temperature and moisture resistance, and low noise during operation, and can work for a long time in harsh environments

10. Simple structure. Suitable for mass production, easy to use and maintain. Cheap price, etc.