Comprehensive Analysis of the Development of Electric Motor Drive Motor and Its Controller in China

1, the type of drive motor and its development drive motor is a key component of electric vehicles, directly affecting the power and economy of the vehicle. The drive motor mainly includes a DC motor and an AC motor. At present, electric motors widely use AC motors, mainly including: asynchronous motors, switched reluctance motors and permanent magnet motors (including brushless DC motors and permanent magnet synchronous motors).

The development trend of automotive motors is as follows:

(1) Permanent magnetization of the motor body: The permanent magnet motor has the advantages of high torque density, high power density, high efficiency, and high reliability. China has the world's most abundant rare earth resources, so high-performance permanent magnet motor is an important development direction of China's vehicle drive motor;

(2) Digitalization of motor control: the emergence of dedicated chips and digital signal processors has promoted the digitization of motor controllers, improved the control accuracy of motor systems, and effectively reduced the system volume;

(3) Motor system integration: Integration of electromechanical integration (motor and engine integration or motor and gearbox integration) and controller helps to reduce the weight and volume of the drive system, which can effectively reduce system manufacturing costs.

2. Foreign development According to foreign data, in recent years, electric buses developed by the United States and Europe have adopted AC asynchronous motors. In order to reduce the weight of the car, most of the motor casings are made of cast aluminum. The constant power range of the motor is wide, and the maximum speed can reach 2 to 2.5 times of the base speed.

Most of the electric vehicles that Japan has introduced in recent years use permanent magnet synchronous motors. The product power level covers 3~123kW, the motor constant power range is wide, and the maximum speed can reach 5 times of the base speed. The overview of electric vehicle drive motors developed in Japan in recent years is shown in Table 3.

3. China's development status:

(1) AC asynchronous motor drive system China has established a development platform with independent intellectual property asynchronous motor drive system, forming a development, manufacturing, testing and service system for small batch production; product performance basically meets the needs of the entire vehicle, high-power asynchronous The motor system has been widely used in various types of electric buses; the product reliability has been initially verified through demonstration operation and small-scale market application.

(2) The switched reluctance motor drive system has formed optimized design and independent research and development capabilities. Through reasonable design of motor structure and improved control technology, the product performance basically meets the needs of the whole vehicle; some companies have an annual production capacity of 2,000 sets, capable of To meet the needs of small batches of supporting equipment, some of the products have been equipped with demonstration vehicles for a long time, with good results.

(3) Brushless DC motor drive system Domestic enterprises have effectively improved the performance of brushless DC motor products by reasonably designing and improving control technology, and basically meet the needs of electric vehicles; they have initially possessed mechatronics design capabilities.

(4) Permanent magnet synchronous motor drive system has formed certain R&D and production capacity, and developed different series of products, which can be applied to all kinds of electric vehicles; some technical indicators of the products are close to the international advanced level, but the overall level is still certain with foreign countries. Gap; basically has the integrated design capability of permanent magnet synchronous motor; most companies are still in small-scale trial production, and a few companies have invested in the establishment of a dedicated production line for automotive drive motor systems.

(5) Permanent magnet motor materials The main materials of permanent magnet motors are NdFeB magnets and silicon steel. Some companies have mastered the overall magnetization technology of magnetizing the rotor magnets of the motor. The maximum working temperature of NdFeB permanent magnets developed in China can reach 280 °C, but the technical level is still far from Germany and Japan. Silicon steel is an important magnetic material for manufacturing motor cores. Its cost accounts for about 20% of the motor body. Its thickness has a great influence on iron consumption. Japan has produced 0.27mm silicon steel sheets for automotive motors. China has only developed 0.35. Mm silicon steel sheet.

(6) Key components of motor controller The position/speed sensor used in motor controller is mostly rotary transformer. At present, imported products are basically used. Some companies in China already have R&D production capacity of rotary transformer, but there is still a gap between product accuracy and reliability. . IGBTs are basically imported and expensive, and domestic automotive IGBTs are still in the research stage.

4. The main problems in China's drive motor and its controller

(1) The research and development capabilities of motor raw materials and controller core components are weak, relying on imports, such as silicon steel sheets, motor high-speed bearings, position/speed sensors, IGBT modules, etc. The high cost of imported products affects the industrialization of motor systems.

(2) The level of electromechanical integration of China's automotive motors is quite different from that of foreign countries. The controller has low integration and relatively large volume and weight.

(3) China's automotive motor system is still in its infancy, the manufacturing process is backward, and there is no automated production line, resulting in poor product reliability and consistency. The scale of industrialization is small and the cost is high.

(4) At present, the standards for electric vehicle drive motor systems introduced by the state are few and not perfect. For example, different types of motor systems use the same test standard, lacking reliability and durability evaluation methods.

Comprehensive Analysis of the Development of Electric Motor Drive Motor and Its Controller in China

Vehicle controller

1. Foreign development The development of vehicle controllers includes software and hardware design. The core software is generally developed by the OEM, and the hardware and the underlying driver software can be selected by the auto parts manufacturer.

(1) Foreign vehicle controller technology tends to be mature Most foreign auto companies have accumulated sufficient in the field of electric vehicles, with high maturity of control strategies and good fuel economy. The controller products have proved their reliability through market inspection.

(2) Automotive electronic components companies are actively developing R&D and manufacturing of complete vehicle controllers.

Various automotive electronic components giants, such as Delphi, China, and Bosch Group, have developed and produced vehicle controllers. Some car design companies also provide complete vehicle controller technology solutions for automakers, such as AVL, FEV, RICARDO, etc. There are also many successful cases in the field of electric vehicle controllers.

(3) The standardization of controllers with standardized controllers has attracted the attention of relevant companies. The global automotive manufacturer, component suppliers and electronics, semiconductor and software systems companies have jointly established the Automotive Open Systems Architecture Alliance to form the AUTOSAR (Automotive Open System Architecture) standard, simplifying the development process and making the ECU software reusable. Is a trend in controller development.

2. China's development status "863" plan China's vehicle controllers are mainly based on universities, such as Tsinghua University, Tongji University, Beijing Institute of Technology, etc., have initially mastered the software and hardware development of vehicle controllers. ability. The product features are relatively complete, basically meet the needs of electric vehicles, and have been applied to sample cars and small batch products. Some vehicle companies cooperate with foreign companies, such as FEV and RICARDO. Through joint development, we will absorb relevant foreign technologies and experiences and enhance our independent development capabilities. At present, all manufacturers basically master the development technology of vehicle controllers, but the technology accumulation is limited and the level is uneven.

China's controller hardware level has a certain gap with foreign countries, and the industrialization capacity is relatively insufficient. Most companies are more inclined to choose foreign vehicle controller hardware suppliers when they introduce mass-produced electric vehicle products. In addition, the controller's basic hardware, development tools, etc. basically rely on imports.

Generally speaking, there is still a big gap between the technical level and industrialization capability of controller products and foreign countries.

3. The main problems of the whole vehicle controller in China:

(1) Most of the application software stays in the function implementation, and the software diagnostic function, the vehicle safety control strategy, and the monitoring function are all to be optimized and improved.

(2) China's electric vehicles are in the stage of R&D and demonstration operation of prototype vehicles, and the basic database is imperfect, which affects the design level of vehicle controllers.

(3) Some enterprises can introduce relevant equipment and software according to the V-type development process (a software and product development tool), and generally use the general development tools for secondary development; the existing tools are biased towards the pre-development, lacking for manufacturing And after-sales service tools are not conducive to the industrialization of products.

(4) Domestic enterprises can complete the hardware structure design of the vehicle controller. However, due to the weak integration of China's chip, the manufacturing capability is poor, and there is still much room for improvement in reliability and stability.

(5) At present, the definitions of controller interfaces and network communication protocols of various vehicle enterprises are different from each other, resulting in poor versatility and reusability between controllers, which is not conducive to the industrialization and scale of controllers.