Optimized Control Research On Coordinated Charging And Discharging Of Hybrid Energy Storage EVs

EV has the advantages of zero emission,high efficiency,simple structure and so on,so it has been developed rapidly in recent years.But the car has two major shortcomings,on one hand,the battery of EV has the disadvantages of low response accuracy,short service life and short mileage.on the other hand,when electric vehicles are connected to the grid,the problems of short time tension and long time low efficiency of distribution facilities will arise.Therefore,the design of the control strategy of the electric vehicle battery and the problem of ordered charging and discharging for electric vehicles are particularly important.In this paper,the control strategy of hybrid energy storage battery for EV is designed,and the problem of ordered charging and discharging for hybrid energy storage vehicle group under the control strategy is studied.The specific work is as follows:First,a schematic diagram of a hybrid energy storage electric vehicle charging and changing system is given.On the one hand,by analyzing the power and energy curve,mathematical model and architecture mode of the energy storage components,a model of the hybrid energy storage battery is established,in which the lead acid battery and the super capacitor series converter and then parallel connected to the DC bus.On the other hand,the disordered charging load of electric private cars and the load of electric taxis are modeled and simulated,and the strategy of stagger peak optimization is determined through the analysis of simulation results.Then,the optimal frequency division control strategy is put forward The first power allocation can achieve that the hybrid energy storage system responds to the lower change rate load,the super capacitor system responds to the higher change rate load.On the basis of first power allocation,the DC bus,ultracapacitor and lead-acid battery respond to three kinds of frequencies: high,medium and low res pectively in the second power allocation based on frequency division control.The correctness and practicability of the control strategy are verified by simulation and experiment.Finally,a residential charging model considering electric taxi stagger peak is established.In this model,the basic load of residential area,uncoordinated charging load of electric private car and electric taxi load are simulated based on the Monte Carlo probability model firstly.Then,the grid method and the quick sort algori thm are used to simulate the charging load curves of EVs under coordinated charging mode,and the simulation results are fitted and put into the Model of stagger peak optimization.The superiority of the control strategy is verified by an example.