Design Of Electric Car Bidirectional DC-DC Converter

With the rapid development of human society,more and more people pay more attention to the phenomenon of not only energy saving but also environmental protection.With the increasing pollution of traditional fuel vehicles,the development of new energy has become more and more concerned among the society.The driving operation of new energy electric vehicles is the use of electricity instead of gasoline,it is not only satisfied energy conservation and environmental protection but also meet the requirement of high energy efficiency,which means it can be a good solution to the problems faced by traditional fuel vehicles.With the new energy electric vehicles have attracted more and more attention,the researchers focus more on research and development,the country increase the intensity of its development,so that the electric vehicles accounting for more and more important role in Chinese energy development strategy.The connection between electric vehicles and dispersed network has unique advantage,however,has challenge that can’t be ignored either,which not also embodied in large scale access network,but also embodied in network load converting as distributed energy storage things.The technology of electric vehicles is still not perfect,nowadays there are many technology that still need breakthroughs and improvements.This paper mostly talk about the important electric vehicle charging-discharging ways and bi-directional DC-DC converter.In the first place,this paper introduces the working principle and performance advantage of bi-directional DC-DC converter.The advantages and disadvantages of several topologies are compared,and their respective application scopes have been discussed.In this article,choose the isolation of the full bridge structure of the bi-directional DC-DC converter.What’s more,the bi-directional DC-DC converter has two control modes,the second chapter discuss phase-shifting control in some detail.It conducted the procedure of the SPS control and the DPS control.By comparing the efficiency of the system,choose dual phase-shifting control as the method of the bi-directional DC-DC converter.Taking advantage of the average model of derail cycle in order to built mathematical pattern of converter.Considering the phenomenon of inherent power backflow in the bi-directional DC-DC converter,the loss of the switching devices and the magnetic elements is increased,and the overall efficiency of the system is reduced that affect the operation of the economy.On account of the bi-directional DC-DC converter have power circumfluence appearance.What’s more,we can see that it due to the DPS control best control method to decrease power circumfluence.Through the analysis of the expression of the backflow power after the unitary,the contour curve of transmission power is compared with the internal and external shift.Making sure dual phase-shifting control can eliminates the backflow power effectively.Moreover,using the simulation software PS CAD is used to simulate the optimal control strategy,it can be found that the comparison of single and dual phase shifting optimization strategies by simulation that it is verified that the dual phase shifting optimal control strategy has a smaller power backflow,high efficiency of the system and the small current stress.Finally,the hardware circuit and the software of bidirectional DC-DC converter system was designed,build the experimental prototype.According to the selection of parameters,we have designed the sampling circuit,drive circuit of IGBT and relay,protection circuit and so on.The software section describes the main program of the system,the initialization program,and the interrupt subroutines optimized based on the dual-shift relative reflow power.At last,carry on a prototype testing in order to verify the practicability of the design proposal.