How to choose new energy vehicle drive motor?

What are the characteristics requirements for drive motors of new energy electric vehicles?

Different from traditional industrial drive motors, the drive motors of new energy electric vehicles usually require frequent starting/stopping, acceleration and deceleration, high torque at low speed/climbing, low torque at high speed, and a wide speed range. The requirements of electric vehicles for drive motors can be summarized as follows: In order to make full use of the limited vehicle space, reduce vehicle mass, and reduce energy consumption during operation, the volume and mass of the drive motor should be reduced as much as possible. The drive motor can use an aluminum alloy casing, and various control devices and cooling systems are also required to be as lightweight and compact as possible.

1. High power density and lightweight. 

Using high voltage as much as possible within the allowable range can reduce the size of the drive motor and the size of the controller, wires and other equipment, especially the cost of the inverter.

2. Efficient operation at full speed and long cruising range on a single charge. 

Especially when the vehicle starts and stops frequently or operates at variable speeds, the drive motor should have high efficiency.

3. Large torque at low speed and wide speed regulation at high speed. 

Even without a transmission, the drive motor itself should be able to meet the required torque characteristics to obtain power under various operating conditions such as starting, acceleration, driving, deceleration, and braking. and torque requirements. The drive motor should have an automatic speed adjustment function, which can reduce the driver's operating intensity, improve driving comfort, and achieve the same control response as traditional internal combustion engine vehicles. Compared with low-speed motors, the volume and mass of high-speed drive motors are smaller, which is beneficial to reducing the quality of vehicle equipment and improving comfort.

4. High reliability. 

The drive motor should have high reliability under any operating conditions to ensure the driving safety of the vehicle.

5. Safety performance. 

The working voltage of high-voltage components such as power battery packs and drive motors can reach more than 300V, which puts forward higher requirements for the safety of electrical systems and control systems. New energy vehicle drive motors must comply with relevant requirements. Safety performance standards and regulations for vehicle electrical controls.

6. Low cost and low noise. 

In order to reduce the use cost of new energy vehicles, the service life of the drive motor should be consistent with the vehicle to truly achieve the goal of energy conservation and environmental protection. At the same time, the drive motor is also required to have good temperature and moisture resistance, low operating noise, simple structure, low cost, suitable for mass production, and easy use and maintenance.

How to choose new energy vehicle drive motor?

The key to selecting a drive motor for new energy vehicles is the mechanical characteristics of the motor. So far, the drive motors used in electric vehicles mainly include: DC motors, AC asynchronous motors, permanent magnet synchronous motors, DC brushless motors and switched magnet motors. Mechanical characteristics can be represented by torque speed characteristics and power speed characteristic curves, and can be used as a reference for selecting motors.

When selecting a drive motor for a new energy vehicle, you can provide the various performance parameters required to the motor manufacturer as a basis for motor design. In fact, in most cases, new energy vehicle manufacturers select off-the-shelf electric motors based on the technical performance parameters provided by the electric motor manufacturer. There are many types of motors available for electric vehicles, with a wide power range. New energy vehicles have relatively high requirements for the drive motor's speed range, reliability, and ability to work in harsh environments.

1. Selection of rated voltage. 

The selection of motor voltage is mainly designed based on the requirements of the overall parameters of the vehicle. Only after the vehicle's dead weight, battery and other related parameters are determined can the motor's voltage, speed and other parameters be determined. That is, when the vehicle's dead weight is determined, The number of batteries is determined, and the voltage level of the motor is also determined. But the overall requirement is: to increase the voltage level as much as possible, so that the motor can make the power of the motor smaller and the current of the motor smaller while meeting the driving requirements, so that the battery capacity selection, installation space, installation method, etc. It's easier to handle.

2. Selection of rated speed 

According to the speed and power performance requirements of electric vehicles, drive motors with different speeds need to be selected.

(1) Low-speed motor 

The speed of the low-speed motor is 3000 ~ 6000r/min. The low-speed motor in the expanded constant power area has high rated torque, large rotor current, large size and mass of the motor, and the corresponding converter and controller The size is also larger, and the losses of various electrical appliances are larger, but the speed ratio of the reducer is smaller. Generally, low-speed motors have large rotational inertia and slow response, making them unsuitable for electric vehicles.

(2) Medium-speed motor 

The speed of a medium-speed motor is 6000 ~10000r/min, and its various parameters are between low-speed motors and high-speed motors.

(3) High-speed motor 

The speed of the high-speed motor is 10000~15000r/min, the expanded constant power zone is wide, the size and mass are small, the size of the corresponding converter and controller is also small, and the inherent losses of various electrical appliances are small . However, the speed ratio of the reducer is greatly increased, and a planetary gear transmission mechanism is usually required. The use of high-speed motors is mainly limited by the performance of electromagnetic materials and the load-bearing capacity of high-speed bearings. Generally, high-speed motors have small rotational inertia, start quickly, and stop quickly. Electric vehicles often use high-speed motors as drive motors.

Ningbo Nide Machinery Equipment Co., Ltd., was established 2010, committing to provide customers with highly automated, intelligent, and flexible production solutions, and focusing on the production line of stator, rotor and final assembly of various motors.

After years of development, NIDE has gradually accumulated a certain influence and brand effect at home and abroad. At present, the products cover the professional manufacture of new energy motor stator and rotor, hairpin motor, automatic aluminum casting rotor line, brushless motor/ BLDC motor, universal motor, wheel hub motor, etc., which are used in new energy vehicles, household appliances, industrial motors, water pump motors, servo motors, etc. The company integrates research and development, production and sales, and wholeheartedly serves customers at home and abroad, delivering value and achieving a win-win situation.