Research On Adaptive Energy Management Control Strategy For Hybrid System Based On Efficiency Optimization

In this paper,based on a uniaxial parallel hybrid system with ISG motor,we analysis system efficiency of hybrid electric vehicles with kinetics at each drive operating mode of the system,in order to improve fuel economy,the work area to basic mode switching system rules are achieved and taking into account the impact of cars driving cycle to energy management control strategy,LVQ condition is used to identify the vehicle driving conditions and the parameters of the control strategy is adjusted,so that vehicle fuel economy in different conditions can be enhance.At the same time,this thesis studies the problem of dynamic torque coordination during mode-switching process;adopting motor torque compensation method,and meeting the power demand of the driver,we reduce the fluctuations of output torque from the input axis of transmission and improve drivability.In order to improve vehicle fuel economy and drivability,the main researches work is as follows:(1)For the selected hybrid system components,this thesis analyses the system efficiency of uniaxial parallel hybrid drive system within the working mode of the engine alone,a single drive motor,driving charge,based on the total efficiency formula and the range of each variable values,we can obtain the working mode shift schedule in acceleration-speed plane,which lay a foundation for adaptive control strategy.(2)the control algorithm of dynamic torque coordination is established for a hybrid system under the drive mode,and coordinated torque control method is designed under driving-mode,which including torque management strategy,the control method of power source,fuzzy control of clutch engagement,and analyzes the control method of torque coordination for typical mode-switching process,and this thesis show a flow chart of the control algorithm.(3)Transforming the working-mode schedule of Chapter II to the flat of required torque and speed of hybrid electric vehicles,and establishing fuzzy controller which membership functions is variable,it can adjust boundary curve of hybrid electric vehicles working-area.Taking fuel economy as the goal,this thesis take advantage of particle swarm optimization to adjust the parameter of membership function so that the most optimal control parameters of six driving cycles.(4)the engine dynamic characteristic was studied,and the engine throttle calculation model and engine dynamic torque output model are built;the dynamic characteristics of ISG-motor is analyzed,and ISG-motor torque output dynamic model is established;Battery model and the control logical of AMT transmission are built,and a vehicle simulation model is established.(5)Under in the conditions of fixed state-switch conditions and consecutive state-switch conditions,By comparing the simulation results of dynamic torque coordination control with no dynamic torque coordination control strategy,it verifies the correctness and feasibility of the proposed control strategy.The result show that the methods of Torque dynamic coordination could reduce the torque fluctuation during working-model switch,decrease jerk,and the same time fulfill driver's torque require.then,taking a Random resultant driving cycle which contains urban cycle,suburban cycle and highway cycle as testing cycle,the simulation analysis of adaptive control strategy is taken,and the show that the energy control strategy in this thesis improve the fuel economy by 7.8% comparing rule-based control strategy.