Coordinated Torque Control Of Power Sources For Driving-Mode-Switch Of Full Hybrid Vehicle

In order to solve the problems of energy crisis and environmental pollution, energysaving、environmental protection become the theme of the future car, it accelerate thedevelopment of new energy vehicles. However, because it is difficult to makesubstantive progress in batteries and other key technologies of battery in a short time,hybrid electric vehicle play its unique advantages during quite a long time.Hybrid electric vehicle exists variety of operating modes, what highlightsincreasingly is the control problem during mode-switch process in the process ofvehicle running. If the control isn’t reasonable, it can cause transmission produce a lotof torque fluctuation, which causes a larger pulse on the whole vehicle, and the outputtorque of system doesn’t meet demand torque of driver, which affects the driving andride performance. Thus, this paper study on the dynamic problem of a kind of fullhybrid vehicle with planetary gear mechanism as dynamic coupling mechanism indriving-mode-switch process, of which power source torque coordination controlstrategy is established to improve ride performance, then research on simulationanalysis for corresponding control strategy verifies its effectiveness. Main work iscarried out as following:①Structural characteristics of full hybrid vehicle with planetary gear mechanismas dynamic coupling mechanism is analyzed, and the parameter of key systemcomponents is given, then the dynamic model of power source and the criticaltransmission components are established.②Based on the way of BP neural network optimized by genetic algorithms,engine torque estimation model is established according to the engine test data. It laythe foundation for the development of mode-switch control strategy.③Dynamic model of power coupling mechanism is established; based on it, thestatus of engine, motor, wet multi-plate clutch and the dynamic models of dynamiccoupling mechanism are analyzed at each operating mode. Next, the status’s changingof engine, motor, wet multi-plate clutch and dynamic coupling mechanism are analyzedduring driving-mode-switch process which is classified into three categories-typicalaccording to the wet multi-plate clutch changing state for making correspondingmode-switch control strategy.④Torque predisrtibution strategy at each mode is studied, including total demanded torque, the mode-switching conditions, engine and the motor target torque;Base on the way that the motor compensates engine torque fluctuation on the basis of anaccurate estimate of engine output torque and the fuzzy control of wet multi-plate clutchtorque, power source torque coordination control strategy of driving-mode-switchprocess is made.⑤Based on Matlab/Simulink, full hybrid vehicle forward simulation model isbuilt. By means of simulation analysis of given work situation and total work situation,the effectiveness of power source torque coordination control strategy is verified in theprocess of driving mode-switch.