Research On Multi Mode Hybrid System Control Strategy Based On Multi Objective Trade Off Optimization

Nowadays,due to oil shortage and serious environmental pollution,and hybrid electric vehicle,which has inherited the advantages of pure electric vehicle and internal combustion engine vehicle,solves the problem of drivin g distance anxiety of pure electric vehicles and reduces the emission of vehicles,it has become an important development direction of new energy automobile.In order to improve vehicle ride comfort and vehicle economy,the control strategy based on multi-objective trade off optimization is proposed in this paper.The main work of this paper is as follows:(1)The structure and driving mode of the multi-mode hybrid electric vehicle studied in this paper are analyzed,then referring to a certain type of car of Changan,the parameters matching and numerical modeling of the key compoinents of the hybrid vehicle are established on the basis of the basic parameters and performance index of the vehicle.The simulation model of the vehicle is built on the Matlab/simulink simulation platform,which provides the basis for the verification of the following control strategy.(2)The energy management strategy based on the equivalent consumption minimum strategy(ECMS)is formulated.First,the objective cost function is constructed with the cost target of the equivalent consumption,and under different driving modes,the torque distribution and cost that minimize the objective cost function under different demand torque and demand speed are obtained through optimization.Then the MAP diagrams of the equivalent consumption cost of different driving modes are integrated,and the working areas of each mode are divided by the way of plane projection.Finally,the control strategy based on ECMS and the rule-based control strategy are compared by the simulation experiment.The result shows that the control strategy based on ECMS can improve the economy effectively.(3)According to the characteristics of different mode switching processes,the mode switching processes are divided into three categories This chapter develops a coordinated control strategy based on combination of model predictive control and traditional coordinated control.The coordinated control strategy for the combination of engine starting coordination and model predictive control is formulated for the first class mode switching process,and the second and third types of mode switching processes are coordinated in accordance with the traditional coordinated control strategy.The effectiveness of the coordinated control strategy of various mode switching processes is verified experimentally through the simulation experiment and the D2P hardware in loop experiment.(4)On the basis of the above research,a multi-objective trade-off optimization control strategy is proposed.Firstly,the torque optimization coefficient of the motor is introduced,and the optimization parameters are optimized by genetic algorithm.The single objective optimization of the motor torque optimization coefficient is carried out with the jerk of the whole vehicle as the objective function.A set of optimal motor torque optimization coefficients is obtained and verified by simulation.Then the equivalent consumption and the jerk of the whole vehicle are taken as two objective functions,the multi-objective trade-off optimization based on the Pareto principle is carried out with the motor torque optimization coefficient as the optimization parameter.A multi-objective optimization control strategy is developed and vernfied.Finally,the effectiveness of multi-objective optimization control strategy is verified through uphill conditions.