| HEV is a model of market prospecting vehicle which is developed in the currentsituation.It will ease the current environmental crisis and the energy crisis.Heavy current willimpact the life of the vehicle power when the car is starting,speeding up and braking, so thestudy of vehicle power has been the key and difficult point at the moment.The articlecombines the battery and the ultracapacitor equipped with DC-DC power converter to formcomposite power supply with active control function,which makes a good use ofultracapacitor’s high power density and high efficiency.And also,it will decrease the impactof the large current, enhance the dynamic property of the car, and improve the working lifeof the system.The article proceedes with the Faw foreign cooperation projects “Research on the keytechnology of composite power supply of HEV”.It will scheme out reasonable scheme forthe composite power supply by working out the energy demand and power demand.Andalso,the article draws up the control strategy for the composite power supply,and optimizesthe composite parameters by NSGA-II.In the end, the author checks the Simulation resultsand experimental results.The paper mainly includes the following respects:1. The simulation platform. Choose a reasonable composite power configurations by thestudy of the vehicle’s configurations, performance and parameter.Design the programaccording to the composite power energy needs and power needs.And then exploit advisoragain by the design requirements and calculated results, set up the vehicle operation of thesimulation platform,and preparate for the next simulation experiment.2. Study on the composite power control strategies.Considering the related articles andthe actual situation of the project team, the author select threshold control strategy for thecomplex logic power control strategy to carry on the design,and get a control strategy thatunder filtering thought and capacitance real-time keep strategy. After the simulation in thesimulation platform,the advantage of the control strategy has been proved which is givingfull play to the super capacitor cut peak and valley role, reducing the current for the impactof the battery, improving battery’s life and efficiency,and improving the operation efficiencyand fuel economy.3. Application of genetic control elite strategy of composite power control algorithm ofthe parameters of the strategy for multi-objective optimization.Under the restriction of thedynamic performance and fuel economy,the article uses the method of hybrid geneticvariation to lower peak current, improve vehicle’s fuel economy and compound the power ofthe parameters of the control strategy for multi-objective optimization design.4. Simulation validation with putting the optimized parameters into simulation system.The result shows that: based on the dynamic performance, fuel efficiency isimproved by5.26%, maximum charge current reduces37.6%, maximum discharge currentreduces13.7%,and we have completed the design goal.Test the result through the physicalmodel of composite power supply system,and prove the feasibility and superiority throughthe experiment under the working condition. The experiment proves that super capacitancegives full play to the role of cutting the peak and valley current in system, eases the bigcurrent of the battery,and protects the battery effectively.This will make estimating the socvalue easily.And also, the energy of the composite system will loss lesser and the efficiencyof system will be improved.This paper applicates logic threshold method to composite power control strategy,andoptimizes parameters with genetic algorithm control strategy.In study of the hybrid cars asthe research object, work out a composite power and composite power control strategymeetting the constraint condition;Verify the superiority and the feasibility of the supercapacitance in the hybrid supply system;It will provide matching parameters reference fordifferent type of performance of composite power control strategy. |
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