Research On Modular Charging Technology For Electric Vehicle

Under the background of deepened global energy crisis,global warming and air pollution,the green development concept of energy conservation and emissions reduction and low-carbon environmental protection have already won the hearts and minds of the people.With today's rapid development of auto industry,compared to the traditional fuel vehicles,the development and promotion of electric vehicles is the most direct support for energy saving and emission reduction.In the process of application and promotion of EV,first of all,we need to improve the matched charging infrastructure services,which is the guarantee of the EV energy supply.In recent years,the researches on high-efficiency,secure,quickly charging technology of electric cars have become one of the focuses of many researchers.This paper puts forward a design scheme of Modular DC charging pile power module.It can realize high power DC/DC conversion,and the output voltage is adjustable.This power module meet the demand of the electric vehicle charging equipment standard.The scheme using single transform structure with DC/DC output can realize constant current and constant voltage output,and meet the technical requirements of battery charging in stages.At the same time,The scheme has the characteristics of modular parallel current sharing,which can meet the needs of capacity expansion and redundancy design,and effectively improve the power level and reliability of the system.Considering the charging pile output power level,and the application of soft switch technology,this design scheme selects ZVS phase-shift full bridge circuit as the main circuit topology of DC charging pile module.This paper introduces the working principle of the ZVS phase shifting full bridge converter,and then analyzes the conditions of realizing ZVS soft switch,deputy side duty cycle loss of the transformer,rectifier diode reverse spike voltage and other key problems and solutions.Finally,this paper analyzes the application of modular technology.The single bus double-loop control of current sharing method for the design of the current sharing program is determined under comparing the various current sharing measures in parallel.The paper also introduces the selection basis of main components of the system the calculation method of parameter design,including the design of magnetic components,semiconductor devices,the selections of capacitance and resistance and so on.According to the scheme proposed in this paper,the prototype of the single module with 7.5kW rated power and 300V?500V continuously adjustable output voltage is designed and tested.The design scheme is analyzed and verified systematically.At first,through Saber software simulation,the rationality of the scheme is verified preliminarily,and then the experimental prototype of two digital control is debugged.Finally,through the analysis of experimental data and the key wave form,the practical feasibility of the design is verified.The design of power module for Dc charging pile in this paper,with features of large output power,high efficiency and continuously adjustable output voltage,has a flexible digital control charging strategy and at the same time adopts modular technology to make charging system with scalable and redundant reserve characteristics,which proved that the scheme has good engineering and practical value.