The Research And Design Of Power Modele For DC Charging Pile

In order to solve the energy crisis in recent years,the electric vehicles and the DC charging piles have acquired rapid development.As the power supply module of DC charging pile is the core of DC charging pile,it is necessary to resreach and design a power module of DC charging pile with Strong anti-interference ability,high efficiency,high power factor,low harmonic,soft switching technology and so on.Two-stage structure is adopted for power supply module of DC charging pile,the former stageadopts the three-phase VIENNA rectifier with staggered parallel,and the one cycle control technology is adopted to meet the requirement of high power factor in industrial applications.After using the automatic balancing function of the output capacitance of the DC bus of the former stage rectifier,a series of two full bridge LLC resonant converters are connected in series for reducing the voltage stress of the power device.By using this scheme,the output power and the output voltage range of the whole power supply module can be improved obviously.Firstly,the basic working principle of three-phase VIENNA rectifier is analyzed in detail,and its core control equation in one cycle is deduced.The large signal mean value model,the small signal model and the current loop small signal model are established,and the key parameter design method of the voltage regulator is given。At the same time,a simulation model is built in MATLAB / SIMULINK.It is verified that the three-phase VIENNA rectifier with one-cycle control can achieve high power factor.Secondly,the working principle of the full bridge LLC resonant converter is analyzed fully,t through fundamental analysis to derive an equivalent circuit model of the converter,the steady state circuit was analyzed,and integrated resonator design parameters.Then,according to the theoretical analysis and design of full bridge LLC resonant cavity parameters,the validity of the analysis of full bridge LLC converter and the availability of parameter design are verified by simulation.Finally,a power supply prototype was designed according to the design of the DC charging pile power module.It can be seen from the experimental results that the single cycle controlled interleaved three-phase VIENNA rectifier has good dynamic performance and stable performance.At the same time,it is verified that the power switch of full bridge LLC resonant converter can realize ZVS turning on and off in the whole range,reducing the circuit loss and improving the whole machine efficiency.