Research And Development On Digital Mode Portable Charger Supply For Pure Electric Vehicles

The emergence of electric vehicles can effectively solve the contradiction betweenenvironmental pollution,energy crisis and the rapid development of the automotiveindusty.Due to limitations of battery technology development,so EV mileague is limited,it isnecessary to charge the battery when SOC is low.But charging pile relatively fixedposition,ease of use greatly reduced,so it is necessary to development a low-cost,flexible andportable charger,to promote the development of electric vehicles.Because of harsh operating environment of electric vehicles,charger must has a dust-tightstructure;As nature cooling method,charger need high efficiency;in order to improving powerfactor and reducing the pollution of the grid when charging,need PFC circuit;in order toimprove the reliability,charger should have light weight,small size,high reliability,resistance tomechanical shock and vibration characteristics.This thesis is based on the technical specifications and protection class,analysis differenttopologies and control methods,select two-stage structure,APFC and DC/DC converter.Bycomparing different APFC topologies’ and control circuits’ disadvantages and advantages,APFC topology select Boost circuit and average current mode control loop,then calculatemaster device parameter.In order to get a wide range of load conditions in highefficiency,various DC/DC circuit topology are analyzed,select PSFB DC/DC topology,andTI’s UCD3138digital power controller is used for the master chip,to improve efficiency andreducing analog circuit,to reducing size.At the same time,calculate DC/DC converter’s masterdevice parameter.Integrated chips of Power Intergrations,TOP266VG,which is simple circuitstructure,small size,high efficiency,multi-channel voltage output,are used for Auxiliary power.This thesis is based on the specific paramenters of two-stage circuits,Pspice and Saberenvironment are used to simulate and optimize parameters,a prototype of2.5kw portablecharger is designed.The prototype is tested,output voltage and ripple factoe to meet the designrequirements.The thesis design of charger is feasible,a theoretical and design optimaization isprovided for designing the charger later.