Optimization Of Energy Management Strategy For Extended Range Electric Vehicle Based On Dynamic Programming Algorithm

With the ever-increasing energy and environmental problems and the support of relevant national policies,new energy vehicles have been vigorously developed.Range-extended electric vehicles have the advantages of long cruising range and pure electric drive.They can be used as a transitional option from traditional fuel vehicles to pure electric vehicles.They have two energy sources: power battery and range extender.Energy management strategies directly determine the performance of the vehicle.This paper takes the extended-range electric vehicle as the research object,aims at the specific driving cycle and the end state of the vehicle,uses a dynamic programming algorithm to solve its energy distribution,and designs a regular energy management strategy based on the global optimization results.Based on experimental data modeling and physical modeling as supplementary method,a model composed of driver model,vehicle controller model,vehicle longitudinal dynamics model,power battery model,range extender model and drive motor model was built.Vehicle simulation model.The simulation platform built is verified based on the road test data of the real vehicle.The simulation results show that the vehicle simulation platform built has good simulation accuracy,which can provide support for the subsequent research on the vehicle energy management strategy.Take the sum of the energy consumption of the range extender and the ohmic loss of the battery as the objective function,and limit the end value of the battery SOC,select the state variable as the power battery SOC,and the decision variable as the output power of the range extender.Under the WLTC test cycle Use dynamic programming algorithm to solve.The simulation shows that compared with the multipoint power following control strategy,the comprehensive fuel economy of the dynamic programming algorithm is improved by 9.05%.From the calculation results of dynamic programming,through statistical analysis and curve fitting methods,the rules of range extender start and stop and output power are extracted respectively,and the rule parameter values are determined by the grid search method to design a regular energy management strategy,and join the power hysteresis link to avoid frequent changes in the operating point of the range extender.The simulation shows that the changes of the vehicle state parameters such as SOC under the two strategies are basically the same.Compared with the multi-point power follower control strategy,the comprehensive fuel economy of the designed regularization strategy is improved by 5.00%,which shows that the designed strategy can be close to dynamic The control effect of the plan.