Research On Energy Flow Analysis Of Pure Electric Vehicle

The rapid development of automotive industry has brought serious environmental and energy problems.As an important measure to alleviate this problem,the pure electric vehicle industry has ushered in an important development opportunity.As an effective way to understand vehicle energy utilization and optimize vehicle economic performance,energy flow analysis is still less applied in the field of pure electric vehicles.At present,there are many studies on vehicle energy consumption and single component performance,but few comprehensive studies on vehicle and components.In view of the above problems,this paper presents the energy flow analysis of pure electric vehicles.The purpose is to have a more comprehensive understanding of the energy utilization of pure electric vehicles through energy flow analysis,and to provide a basis for vehicle design and optimization.In this paper,an A00-class pure electric vehicle is taken as the research object.According to the energy flow theory and the relevant test standards of electric vehicles,the energy flow test scheme of pure electric vehicle is designed.The signal acquisition methods for the operation and charging state of pure electric vehicles are respectively formulated to realize the electrical signal acquisition and monitoring of main components such as chargers,power batteries and drive motors.According to the purpose of the test,ECE,NEDC,WLTC and60km/h constant speed cycle were determined as test cycles,and test items were established.The chassis dynamometer was used to test the vehicle under different working conditions under different conditions.Based on the test results,the energy flow analysis of the driving and charging states and the operating point analysis of key components such as the power battery,the drive motor,and the DC/DC converter are performed.The results show that the overall performance of the pure electric vehicle is good,but there are some shortcomings.The test vehicle has good power matching effect.The working efficiency of battery system and motor controller is more than 90% while the working efficiency of DC/DC converter is more than 80%,which can meet the economic requirements;the working efficiency of the driving motor can reach more than 90% under the driving state,while the working efficiency under the braking state is not high,less than 70%;the energy consumption of low-speed operation of transmission system is high,which is 24%.Under the charging condition,the overall efficiency of the charging system is higher,all above 90%,which meets the performance requirements of common vehicles of the same level.According to the analysis results,some optimization suggestions are put forward from the aspects of improving the low-speed working efficiency of mechanical transmission mechanism and optimizing the operation MAP of motor as generator,so as to further improve the energy utilization of pure electric vehicles.