Study On Control Strategy Of TCS For Hybrid Electric Vehicle

Nowadays, energy conservation and environmental protection are the principal theme of automobile industry. Hybrid Electric Vehicle is the most promising among electric cars and will replace traditional fuel cars gradually. As a result, the security of Hybrid Electric Vehicle absorbs an increasing attention from people. Traction control system can improve dynamic performance and lateral stability of the vehicle by preventing driving-wheels from excessive slip. Compared with traditional cars, hybrid vehicles increase the torque adjustment because of its equipped with multi-power source which include motor and engine. So the research on control strategy of Traction control system for hybrid vehicle is of great significance.A single shaft ISG mild parallel hybrid electric vehicle is studied on in this dissertation, according to the idea of “Modeling-Design Control Strategy-Simulation” to research control strategy of Traction control system, and the rapid control prototype simulation test for the control strategy based on dSPACE real-time system was implemented. The main work is summarized as following.According to the composition and structure of the hybrid and TCS research needs, the Engine model, ISG motor model, tire model using magic formula were built based on experimental data, and power train model, seven-DOF vehicle dynamics model were developed based on physical logic on the platform of Matlab/Simulink. These models provide the simulation and verification foundation for the control strategy.Then, target driving torque control strategies and allocation strategies for the TCS of Hybrid Electric Vehicle is studied. The target driving torque was made based on sliding mode control algorithm and which determine the optimal driving moment based on vehicle speed, slip rate of driving-wheels and other variable of the car when it runs. The driving torque allocation strategy is based on fuzzy control algorithm and according to the characteristics of ISG motor response to torque is fast and accurate to distribute the torque of engine and motor with the aim of engine optimal.Based on the environment of Matlab/Simulink, offline simulation analysis was implemented on four kinds of typical road conditions to validate the effectiveness of the control algorithm and strategy, including low-mu road, the split road, mu-jumped road and checkerboard-mu road. The results shows that the control strategy of TCS has better control effect,can effectively prevent driving-wheels from slipping excessively and the driving stability, power performance and fuel economy are also improved.The rapid control prototype simulation test is done based on dSPACE real-time system. The real-time simulation results and offline simulation results are basically identical, which validate the effect of TCS control strategy further.