Electric Drive Axle Design And Test For The Pure Electric Vehicle

Along with the energy crisis and environmental protection consciousness enhancement, especially because of the national wide range haze weather in the second half of 2014, people are made to pay more attention to pure electric vehicles. Traditional automakers at home and abroad tend to post product higher, which makes it difficult to spread in the mass consumer groups, while small miniature pure electric vehicles and pure electric environmental vehicles with compact structure, light in quality and low cost advantages, as supplements for high-end pure electric vehicles, will have great potential for development. The electric drive axle is the core component of this kind of pure electric vehicles, including electric drive axle machine structure and drive control system. The key point of this paper is to study how to guarantee the enough strength of electric drive axle structure and good control performance of its drive control system while meeting the design performance requirements.After determining the basic performance parameters of the design object, the paper is designed from two aspects of mechanical structure of electric drive axle and drive controller system.Based on the analysis of the motor and the drive axle arrangement, the electric drive axle is designed, mainly including half shaft, main reducer, differential and bridge shell parts, etc. According to three kinds of typical working condition analysis, the basic parameters of the parts are determined by theoretical calculation; electric drive axle virtual prototype is established in CATIA; all parts’strength and fatigue are examined by finite element analysis method.Design of drive control system begins with the mathematical model of permanent magnet brushless dc motor. According to the mathematical model of the motor and by using the Matlab/Simulink toolbox, speed loop and current loop of the double closed loop PI control system model are set up. At the same time, the simulation waveform is concluded, which provides main basis for the drive control system hardware and software design. In addition, the control system hardware design is carried on and the paper analyzes the module of the power supply and testing, the module of photoelectric isolation and power driver, the module of current limiting current signal detection and feedback, the module of Hall signal testing, etc. what’s more this paper elaborated the drive software of the control system implementation scheme, and gives the main program flow chart and part of subprogram flow chart.To test and verify the accuracy of theoretical analysis and the feasibility of the scheme, and to complete the electric drive axle manufacturing prototype and drive controller, the drive controller test bench is set up in laboratory based on NI data acquisition system. Motor function waveform is collected and analyzed, such as torque and rotational speed waveform, and the waveform is analyzed, with the control performance reaching the design.