Research On Energy Control Strategy Of Pure Electric Vehicle Composite Power Supply

In recent years,with the increase in the number of traditional fuel vehicles,the global fossil energy consumption and carbon dioxide emissions have increased year by year,and pure electric vehicles have attracted widespread attention due to their energy-saving and emission-reduction advantages,and the market scale is increasing.However,the pure electric vehicle single-power vehicle on-board energy storage system still has shortcomings such as low energy density,fast capacity decline and poor low temperature performance,and the composite power supply can maximize the integration of super capacitors and power batteries through reasonable structure and efficient energy control strategies,and improve the overall performance and service life of on-board energy.The integration of on-board energy improves the overall performance and service life of the vehicle.Therefore,this paper designs a new type of high-voltage composite power supply with series-parallel adjustable and operating voltage of 400-600 V,and conducts related research on composite power supply structure design,simulation parameter matching,control strategy analysis and model simulation verification,including the following contents:First,after comprehensively analyzing the advantages and disadvantages of passive,power battery active,super capacitor active and fully active composite power supply structures,the super capacitor active composite power supply structure is selected as the basis,adding a two-contact ideal switch and a one-way boost DC/DC converter,design a new composite power structure,and describe its 5 different working modes,and analyze the characteristics of power battery,super capacitor and DC/DC converter.Then,in order to carry out the simulation verification of the composite power supply,the parameters of the drive motor are matched according to the maximum speed,acceleration and climbing performance requirements of pure electric vehicles;the parameters of the battery pack are matched according to the NEDC driving range requirements and motor power requirements;the parameters of the super capacitor group are matched according to the single maximum braking regenerative energy under UDDS operating conditions.Then,in order to reasonably allocate the output power of super capacitors and power batteries,a composite power control strategy combining logic threshold control and fuzzy control is designed,and the logic control rules of the vehicle are analyzed at the same time,and fuzzy control rules and membership functions are set based on experience.Then,the membership functions parameters of the fuzzy controller are encoded.On the basis of the non-interface simulation of the vehicle model,the minimum energy loss per unit mileage and the peak current of the power battery are the optimization goals,and apply the Sparrow Search Algorithm(SSA)to optimize the membership function,and analyze the optimization results.Finally,the secondary development of ADVISOR is carried out,and Matlab/Simulink models of power batteries,super capacitors,DC/DC converters and controllers are established to form a new hybrid power supply pure electric vehicle model,and simulation experiments are carried out to verify the results.Compared with the traditional structure composite power supply and the single-power supply,the energy loss of the new structure composite power supply is reduced,and the new structure composite power supply optimized by the SSA algorithm has less loss than before optimization.In addition,the new structure composite power supply performs better in reducing peak current than the traditional structure composite power supply,the super capacitor utilization rate and energy recovery efficiency are higher,and the driving endurance is stronger.