| Faced with increasingly serious air pollution and fossil energy shortages,electric vehicles with zero-emission characteristics during driving have been favored by governments around the world.At present,electric vehicle replenishment is mainly through wired charging through charging piles in parking lots.With the deepening of the field of electromagnetic waves and the theoretical research of electronic technology,it has gradually become possible to apply Wireless Power Transfer(WPT)technology to the charging of electric vehicles.Through the mutual conversion of electricity and magnetism,it can avoid the problems of wear,aging,corrosion and tip discharge of traditional wired charging connection cables,and it’s more suitable for safe and intelligent charging in extremely harsh environments such as humid environments,rain and snow.This article mainly studies the circuit applied to the WPT charging system of electric vehicles.The parameter design of the experimental system is carried out on the basis of the completion of modeling and simulation research.The main research contents are as follows:(1)Investigated the main methods and research status of WPT technology realization,analyzed the demand of electric vehicle wireless charging,and summarized the current research hotspots in the field of electric vehicle WPT.(2)Taking the resonant system including the compensation capacitor and the transmitting and receiving coil as the main research object,the mathematical model of the resonant system in the magnetic coupled resonant wireless power transmission(Magnetic Coupled Resonant WPT,MCR-WPT)system is established through the theory of magnetic coupling.And based on the loss model of the inverter and rectifier,a complete mathematical model of the MCRWPT system is established.Based on the complete mathematical model of the system,the effects of five parameters including the coupling coefficient between coils,load resistance,input DC voltage,resonance frequency and driving frequency on the overall efficiency of the system,the efficiency of the resonance system and the output power are studied in detail.(3)Aiming at the compensation circuit structure of the system,the circuit structure of Double LCC(DLCC)compensation is analyzed in detail,and a mathematical model is established.The parameter optimization design method of DLCC compensation circuit is proposed.In the case of using the same coil and load,the efficiency of the WPT system using the DLCC compensation circuit is higher than that of the WPT system using the Series-Series(SS)compensation circuit.And built a system simulation model to verify the design method.(4)The working mode of the inverter in the system is analyzed,and a control method of accurately adjusting the driving frequency to realize soft switching is proposed,so that the soft turn-on or soft turn-off of the inverter can be realized without changing the hardware structure and parameters of the system.An electric vehicle magnetic coupling resonance WPT experimental platform with a maximum input power of 6kW is designed.The system influencing factors and the parameter optimization design method of the DLCC compensation circuit are verified through experiments,and the system’s anti-coil lateral deviation ability is studied.The WPT system with DLCC compensation circuit was tested with an input power of6 kW,and the experimental results showed that the highest efficiency reached 93.6%. |
PDF Full Text Request