Modeling Of Control System And Study On Control Strategy For The Pure Electric Passenger Cars Based On Modelica

Pure electric vehicles will become the focus of the research and development of the automobile in the future. The development of control strategy is the key technology of pure electric vehicles, and play a very important role in improving the dynamic performance, economy, security and reliability of electric vehicles. Efficient development mode and modeling techniques contribute to the study of control strategy which is help ful to enhance the performance of vehicle. In this paper, the following several researches are carried out:First of all, this paper analyzes the vehicle structure,control function and the control scheme of pure electric vehicles. And then a kind of vehicle control system is put forward based on the signal bus to solve complex data exchange between different types of electronic systems.Secondly, this study divides and elaborates the operation mode based on the kinematics analysis of the pure electric vehicle. Specifically speaking, the model of the driver intention expression is established based on the classical control theory. In order to make a research on the starting mode control strategy based on the pure SOC, the acceleration signal and the brake signal are studied by analyzing the process of starting kinematics in detail. A series of drive control strategy for operation modes, including general acceleration, uniform and deceleration, are also carried out. To analyze the operation mode and the switching mode, the characteristics of the Modelica language is used, and a vehicle state switch control strategy is proposed based on StateGraph to complete visual modeling of vehicle's operation modes switch.What's more, the regenerative braking strategy and the stability control strategy are also discussed on the basis on StateGraph.(a) The working principle and influencing factors of the regenerative braking system are analyzed. The regenerative braking control strategy is studied by taking account of the impact factors of motor and batteries.(b) Based on the logic threshold control method, ABS and TCS control strategy with the wheel slip ratio and angular acceleration are researched.(c) Based on the analyzing of the ESP control system, a braking control logic with the yaw rate and the lateral velocity is proposed.Finally, the vehicle controller models are established in Mworks which is a modeling and simulation platform based on Modelica language. And the vehicle simulation platform is built according to the signal bus control system scheme. In order to verify the performance of different control strategies, a variety of working conditions are designed and a simulation method is analyzed for pure electric passenger cars(ECUV). The effectiveness and the superiority of the control strategy are also verified according to the contrast analysis of the simulation results.