Electric Vehicle Driving System Modeling, Simulation And Hardware-in-the-loop Test

With the growth of non-renewable energy consumption and environmental pollution of the earth is becoming more and more seriously, the government departments and related researchers gradually prefer to pay more attention to the new energy vehicle than the traditional internal combustion engine vehicle. Electric vehicles based on battery powered are favored by people due to its high energy efficiency, less energy supply chain pollution, technology is mature relatively and easy in industrialization。The electric driving system is the core component of an electric vehicle, it mainly include driving motor and its control system, Power battery and its management system. The design, development and testing of electric driving system is the key to ensure the performance of electric vehicle. In order to study the electrical drive system more convenient, researchers usually adopt the simulation modeling technology to build the real establishment into virtual model in the early design. Using The Hardware-in-the-Loop(HIL) test for electronic control unit(ECU) can detect early design problems of ECU before Bench Testing and vehicle testing, it also can decrease the cost of research and development.The paper is combined with the needs of actual project, focus on the electric driving system design, modeling and simulation of electric vehicle, it also include The build of the HIL simulation platform and HIL test for motor controller. The main research contents include:①The type of electric driving system in electric vehicles is analyzed to determine the electric driving system layout. According to the parameters and Performance index of the electric vehicle, the design of electric driving system parameters matching is done. Test selection and product characteristics of the driving motor and power battery system is done to obtain the parameter and index for electric driving system modeling and simulation.②The driving motor mathematical model based on the coordinate transformation is analysised. Introduce the principle of permanent magnet synchronous motor(PMSM) vector control and the method of the PMSM driving motor vector control for electric vehicle. List and explain several kinds of battery modeling methods. A modeling method of lithium ion battery is put forward which is convenient of setting simulation parameters based on equivalent circuit model.③The simulation model of electric vehicle is constructed using MATLAB/Simulink software. Focus on the modeling method of vehicle dynamics model, driver system model, PMSM model and power battery model in the software. The dynamic performance of the electric vehicle is verified by simulation. The simulation analysis of the actual and target changes of vehicle speed, the percentage of Accelerator/brake pedal, the target and actual torque of driving motor, the actual power of driving motor, and the changing rules of power battery SOC of NEDC cycle are analyzed by simulation. Simulation results show the rationality of the driving motor and power battery design and selection, and the validity of the modeling method. It also proves that the response of the vehicle simulation model is good. Vehicle off-line simulation model can be used as the basic model of HIL simulation test.④The basic principle of HIL simulation test is introduced. A “Double-computer” real-time simulation method is proposed based on Simulink Real-Time environment. The Simulink Real-Time environment build steps is Described, including the software and hardware configuration of host and target computer, the production of target computer startup disk, communication method and communication test of “Double-computer”. According to the test signals of the motor controller, data acquisition cards and CAN communication card are selected. The writing method of S-function in simulink is introduced. Make an example of PCI-1716 card DI driver in the Simulink Real-Time environment, giving the steps of writing complete driver Program and the Packag method of driver module. The underlying hardware architecture of HIL testing system is designed, the HIL test system working mode and the signals transmission path is elaborated.⑤According to the data of monitoring requirements,the host computer interface of HIL test system is designed. the design of HIL interface of computer test system. HIL test cases are writed based on the function of motor controller system design. System level functional test of motor controller is done via the test cases. The main test items are: motor transient response speed in the electric vehicle acceleration process, motor brake energy recovery function, limit function of minimum motor speed during energy recovery braking and over-voltage protection function of motor controller. After HIL testing, each test result is detailed analysised respectively. The final conclusion is: every HIL test results comply with the design requirements of motor controller, and all HIL tests pass.