Research On Control Strategy And Method For Typical Mode Switching Process Of Hybrid Vehicle

With the problem of global oil resources shortage and climate environmental pollution getting more and more serious,developing new low fuel consumption and low-emission vehicles has turned into the theme of automobile industry from now on.The HEV(Hybrid Electric Vehicle)has been one of the effective means to relieve the shortage of energy sources and deterioration of the environment with the advantage of its flexible structure and easy implementation.HEV is equipped with an engine propulsion and a motor propulsion,the vehicle will work in different modes based on different working conditions,also the mode can change from one to the other.For the existence of power coupling between engine and motor,the dynamic coordinated control problem is solved well or not,which will seriously affect the durability,comfort and power of the hybrid vehicle.Therefore,it is very important to study the control problem for mode-switching of the hybrid electric vehicle.Taking the single-shaft parallel hybrid electric vehicle as object of our study,the main researches in this paper are as follows:(1)Analysis of the structure for single-shaft hybrid system,several typical working modes are introduced briefly and the mode-switching processes are divided into many types,the performance indicators of control for mode-switching process are introduced.(2)To take the electric to the engine driving mode-switching process as emphasis,put forward corresponding control strategies and methods,and the vehicle dynamic model of each stage are established.In the view of impact and slippery power are contradictory,to find the optimal law and make the target function optimal by using quadratic optimal control theory and method.According to the fuzzy relationship between the driving intention and the weight matrix of quadratic optimal control,the dynamic adjustment of matrix is researched based on fuzzy reasoning.(3)In the Matlab/Simulink environment,the hybrid vehicle model is built,control strategies and methods are simulated and analyzed.Simulation results show that the friction of the clutch is reduced and the fastness of mode-switching is improved by control strategies proposed in this paper,furthermore the impact of torque during power coupling is dropped.According to the driving intention,the method of adjusting weight matrix dynamically based on the fuzzy reasoning is correct and feasible.(4)The hardware-in-the-loop(HIL)simulation system based on xPC target is built,then the hardware and software platform of the test system are completed and debugged.To realize the control strategies and methods by using real controller,and the control algorithm is tested and verified.The operation of control algorithm meets the design intention and real-time requirements because the results of HIL simulation is as same as the computer simulation.