Development status and trend of new energy vehicles
Electric vehicles are not suitable for long-distance transportation, and the future is mainly based on urban traffic. From the perspective of industrialization, the first to do is the passenger car. From the perspective of technology and market share, Yutong Bus is a model. Followed by a small car, it is estimated that there will be some competitive cars coming out during the year. From the perspective of China's automobile industry competitiveness, there are three areas that are more suitable for the development of new energy vehicles: 1) commercial vehicles, represented by passenger cars, the largest scale of production and sales of passenger cars; 2) small cars, China's own brand cars are concentrated in A or A0 level; 3) Special vehicle. Such as sanitation, official vehicles and so on.
Electric vehicle classification: New energy vehicles include pure electric vehicles, fuel cell vehicles, plug-in hybrid vehicles and extended-range electric vehicles. Non-plug-in type is classified as energy-saving cars. The plug-in hybrid car is different from the extended-range electric car. The plug-in hybrid car is mainly fuel-based and supplemented by electric power. The pure electric mode runs 20-60 km; the extended-range electric car runs 50-80 km in pure electric mode. Mainly to electricity, supplemented by fuel.
China's long-term strategy is to develop pure electric vehicles. Now energy security issues, environmental protection issues, and the transformation and upgrading of the automobile industry are all more urgent than before. The government's attitude toward promoting new energy vehicles is now stronger than in 2010.
From the aspect of fuel consumption regulations. Our country's fuel consumption standards stipulate that by 2020, the average fuel consumption of passenger car enterprises should reach 5.0L per 100 kilometers. It is impossible to achieve the standard of energy saving and new energy vehicles.
Poor vehicle working conditions, more constraints on the drive motor system
The car is a very special product, especially for a family car. Its space is large, the motor needs high density, miniaturization and light weight. The electric car drive motor needs high efficiency and high adaptability.
Wide speed regulation of low speed and high torque and high speed and constant power: high torque is required when starting and driving the vehicle, and constant power output can be performed at high speed; the base speed and maximum speed of the motor are very different, requiring a wide speed regulation range.
The reliability, durability and adaptability of the driving motor are poor. Due to the vibration of the vehicle and the high temperature environment of the engine room, the motor runs under the harsh environment of large vibration, large impact, dust and large temperature and humidity changes. The motor for the vehicle must adapt to the requirements of environmental conditions to make the motor reliable, stable and safe.
Low noise and low cost: The cost of the motor is one of the important factors that determine whether the electric vehicle can be industrialized.
Main types of motors and their applications in vehicles
The motor is divided into a DC motor and an AC motor. Now DC motors are mainly used in some low-speed electric vehicles. The asynchronous motor in the AC motor is mainly used as the traction motor of the electric passenger car, and the permanent magnet synchronous motor is the mainstream route of the drive motor of the new energy vehicle.
The working condition of the vehicle is very bad, so the requirements for the vehicle drive motor are very high, which leads to the three technical development trends of the motor system for the vehicle: integration, permanent magnetization and digitization.
Motor and engine assembly, motor and gearbox assembly. Hybrid and plug-in hybrid passenger cars, motors and gearboxes are fully integrated; the requirements for this bus are not the same, the passenger car requirements are lower than the car.
Permanent magnetization: The permanent magnet motor has high power density and torque density, and has the advantages of high efficiency, high power factor, high reliability and easy maintenance.
The vector control drive control system achieves a wide range of speed regulation.
Digitization: The digitization of control systems is an inevitable trend in the development of electric drive technology. The controller aspect mainly refers to the power electronics assembly. The integration of controllers is getting higher and higher. The difference between us and foreign countries is mainly volume. In China, IGBT modules are generally used for integration.
Current status and progress of domestic drive motor research and development and industrialization
1. Comparison of technical level and foreign level
The technical index of the drive motor has been almost the same as the international level. The power density of the motor can reach 2.68KW/KG, and the high-efficiency area of the motor system is further widened. The highest efficiency of the system is over 94%.
Technical challenges: There are still deficiencies in reliability and environmental adaptability assessments. The DC/AC and DC/DC power electronics assemblies are bulky.
The key power electronic components still need to be imported, and the cost accounts for nearly half of the controllers. At present, enterprises have begun to develop and try them out. The upstream industrial chain has not yet been fully formed, and the quality has not yet fully met the needs of the automotive industry.
2. The gap between the industrialization level and the foreign level
There are still some gaps in industrialization and foreign advanced levels. For example, the Prius, its annual production and sales scale is very large, and our degree of industrialization is different from them.
The professional process and manufacturing process technology for industrialization needs to be improved; special processing equipment and test equipment: most of the key production equipment and instruments in the field of drive motors are mainly imported, and domestic equipment manufacturers are mainly involved in the low-end market. Motor production line construction and quality management system.
3. According to the needs of the industry, the key areas need to be strengthened.
1) Common key technologies for common modularization, reducing the research and development costs of the industry.
2) Strengthen electromechanical coupling design and integrated integration to improve vehicle adaptability.
3) Strengthen key common technology research and establish effective technical indicators and evaluation systems.
4) Strengthen research and application of reliability, durability and environmental adaptability technologies.
5) Develop key equipment in conjunction with major national projects.
