Study On Integrated Powertrain Control Strategy For An Electric Bus

The pure electric bus,which is welcomed by more and more Chinese urban residents,has many advantages such as no pollution,low noise,simple structure and national policy support and so on.With the growing demand for vehicle functions,cars with more and more distributed electronic control units(ECUs)lead to problems such as communication delay,poor stability,and difficulty in coordinated control of the vehicle’s electronic control system,which in turn affects the safety of the entire vehicle.However the integration of ECU can effectively solve the above problems.According to the school-enterprise cooperation project,through comparing the research status with development trend of the control strategy and integrated control of the electric vehicle powertrain,the feasibility study of integrated control for pure electric cars’ electronic control system is carried out and verified by experiments based on the existing dSPACE and TTC.Firstly,this article takes a pure electric bus as an example to analyze the problems of the traditional distributed architecture electronic control system.The feasibility of integration analysis from two levels of software and hardware is made and the integrated solution of BMS and VCU is determined on the basis of laboratory’s existing foundation,which establish the entire vehicle electrical architecture and redefine the entire vehicle function.As for the change of the electronic control system architecture before and after the integration,the impact of controller integration on the electronic control system is compared and analyzed from four aspects and the results show that the integration can reduce the signal transmission and control time of the electronic control system,reduce the load of power CAN,and accelerate the response time of battery fault,but the real-time prediction of the SOC is hardly changed.The vehicle model is divided in light of the integrated vehicle electronic control system under integrated control,and the integrated control strategy is formulated according to the characteristics of the drive motor and the power battery.The modularization modeling of the control strategy is completed using MATLAB/Simulink.In order to study the operation of the integrated control strategy in the controller,the 7 modules of the integrated control strategy are mapped into 6 tasks in accordance with the independence of the function.Through the study of the typical scheduling algorithm,the schedulable for periodic tasks is established.The execution time of a single task is measured and then the schedulability of the task set is theoretically analyzed and verified by dSPACE.For the sake to verify the correctness of the integrated control strategy,the complete vehicle dynamics and powertrain key component model are built.Combined with the actual needs of the project,CodeSys software development tools is used to achieve integrated controller development on the TTC60 controller,and the effectiveness and rationality of the integrated control strategy is verified from the three aspects as off-line simulation,HIL testing and vehicle testing.Based on the research of integrated control and modeling,this paper establishes a simulation and verification technology platform for the whole vehicle and its control system and develops an integrated control algorithm.Through the system simulation and HIL and vehicle test,the practicability and effectiveness of the system integration design are analyzed and compared,so as to provide some guidance for the integrated development of the electronic control system.