3. China's development status
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 whole vehicle, high-power asynchronous motor system has Widely used in all types of electric buses; product reliability has been initially verified through demonstration operations and small-scale market applications.
The switched reluctance motor drive system has formed an optimized design and independent research and development capabilities. Through reasonable design of the motor structure and improved control technology, the product performance basically meets the needs of the entire vehicle; some companies have an annual production capacity of 2,000 sets, which can meet small batches. Supporting demand, some products have been equipped with demonstration vehicles for a long time, with good results.
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.
The 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 still has a certain gap with foreign countries; It 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.
The main materials of permanent magnet motor of permanent magnet motor material are NdFeB magnet 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. Only 0.35 has been developed in China. Mm silicon steel sheet.
The key components of the motor controller The position/speed sensor of the motor controller is mostly a rotary transformer. At present, imported products are basically used. Some companies in China already have the R&D production capacity of the rotary transformer, but there is still a gap between the accuracy and reliability of the product. 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
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.
The level of electromechanical integration of motor motors in China is quite different from that in foreign countries. The controller has low integration and relatively large volume and weight.
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.
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