At present, electric vehicles are in high-speed development, and as the core driving force of electric vehicles, electric vehicle motors are also widely concerned. But few people really know electric vehicle motor. Qingdao AIP Intelligent Instrument Co., Ltd. collects various documents and shares the knowledge of electric vehicle motor. Let's learn the heart of high-tech cars!

Importance of electric vehicle motor

Electric control system is the brain of electric vehicle, which commands the operation of electronic components of electric vehicle. Vehicle energy system is the core technology of electric control system. It is a link connecting battery, battery pack and vehicle system, including battery management technology, vehicle charging technology, DC technology and energy system bus technology. Therefore, vehicle energy system technology has become an important direction of industrial application technology research, and also an important sign of industrial development. At present, this technology has become an important bottleneck restricting the connection and development of the electric vehicle industry chain.

Electric vehicle motor classification

Now, the main motors used in electric vehicles are DC motor, AC induction motor, permanent magnet motor and switched reluctance motor.

1. Electric vehicle DC motor

Advantages: Large starting acceleration, good electromagnetic torque control characteristics, convenient speed regulation, simple control device, low cost.

Disadvantages: Equipped a mechanical commutator, when running at high speed and large load, there is spark on the surface of the commutator, so it should not be too high motor speed. Compared with other drive systems, it is at a disadvantage and has been gradually eliminated.

2. Electric vehicle AC induction motor

The stator of AC induction motor is used to generate magnetic field, the motor is composed of stator core, stator winding, outer shell of core and bearing supporting rotor shaft. AC motor has the advantages of low price, easy to maintain and small size, but the control of AC motor is complex. It has become the first choice of AC drive electric vehicles.

3. Electric vehicle AC induction motor

Permanent magnet is used to produce air gap flux in permanent magnet motor, which replaces the field coil in DC motor and the exciter in stator of induction motor. Permanent magnet synchronous motor (PMSM) has the advantages of high efficiency, high moment of inertia ratio, high energy density, especially its low speed and large torque, which can meet the requirements of vehicles driving on complex and changeable roads. It is a high-performance and low-carbon environmental protection motor with the emergence of rare earth permanent magnet materials, which is expected to compete with AC induction motor for market. Especially in the small and medium power range, it has been widely used.

4. Electric vehicle switched reluctance motor

The stator and rotor of SRM (switched reluctance motor) are double salient structures made of common silicon steel sheets.

Advantages: Simple and reliable, wide adjustable speed range, high efficiency, flexible control, low cost.

Disadvantages: Large torque fluctuation, large noise, need position detector, nonlinear characteristics, limited application.

The power performance of the electric vehicle has a direct relationship with the power of the electric vehicle. The greater the power, the better the acceleration performance and the maximum climbing ability of the electric vehicle, and the better the quality. At the same time, the volume of the motor will increase, but the motor cannot work under high efficiency for a long time, which will reduce the capacity utilization rate of the electric vehicle and the driving mileage of the vehicle.

Generally speaking, the rated power of the motor should meet the requirements of the maximum speed of our car, and the peak power of the motor should meet the requirements of the maximum gradient and acceleration performance of the car. 

How to test electric vehicle motor

The test of new energy vehicle motor is particularly important, which is directly related to the running state of the vehicle. Only the motor that meets the relevant functional items test can be competent for such a difficult task. AIP will tell you how to test.

1. Test of motor drive system

The motor drive system is the core part of the electric vehicle, which converts the DC bus voltage from the battery into AC and drives the motor with AC.

2. Test of battery charging system

The battery charging system is to convert the alternating current in the charging devices such as the external charging pile and charging station into the direct current to charge the battery in the pure electric vehicle and store the electric energy in the battery. The main function of the DC load power supply system is to convert the stable high-voltage of the DC bus output from the battery in the electric vehicle into the low-voltage output to supply the low-voltage DC load in the vehicle.

3. Test of DC voltage stabilizing system

Due to the frequent charging and discharging, the voltage at both ends of the battery is a floating voltage within a certain range. It is necessary to stabilize the voltage within this range in a stable DC bus voltage for direct application or other voltage conversion.