| With the increasing popularity of electric vehicles,the way of changing electricity has become a research hotspot.Nowadays,the vast majority of electric vehicle charging is to transmit energy through transmission lines.This wired charging method is not suitable for some special occasions.Therefore,WPT(wireless power transfer)technology of electric vehicle radio energy transmission came into being.Among them,the research of magnetic coupling resonance electric vehicle wireless charging systems is more popular.However,the WPT technology has just started.Although it has the advantages of safety and convenience,the system transmission efficiency needs to be further studied for the practical application of industrial products.Magnetic coupling resonance electric wireless charging system is vulnerable to external interference,which leads to the low transmission efficiency of the system for many reasons.On the one hand,as the key component of energy transmission,the design of magnetic coupling coil is the most important;On the other hand,because of its resonant working principle,how to ensure that the system is always in the resonant state is the focus of whether the system can transmit energy efficiently;The focus must be the hot spot of research.Therefore,this paper mainly carries out the research on relevant aspects based on the above two aspects:Firstly,when the WPT system works normally,in order to improve the transmission efficiency of the WPT system in the resonant state,the simplified circuit modeling of the WPT system is selected first.The expression of system transmission efficiency is obtained.It is analyzed mathematically that the goal of improving system transmission efficiency is to improve the coupling coefficient of magnetic coupling coil.With the help of Maxwell magnetic field analysis software in finite element analysis software ANSYS,this paper analyzes the influence of some main parameters of magnetic coupling coil on system energy efficiency,and then summarizes the idea of optimal design of magnetic coupling mechanism.Secondly,combined with the above optimization ideas,the magnetic coupling coil structure is optimized through the finite element analysis software ANSYS Maxwell.A new combined anti offset coil structure is designed,which takes into account the advantages of anti longitudinal and transverse offset;Combined with Simplorer software,the coil design is simulated and verified to meet the requirements of system transmission efficiency,which can be used as a reference for the design of wireless charging coil of electric vehicle in the future.Then,considering that the wireless charging system of electric vehicle always works at high frequency,when the inductance of the transmitting coil at the energy generation end of the wireless charging system changes slightly,the resonant frequency of the wireless charging system changes,and the system is in a non resonant state,which will reduce the transmission efficiency of the system.In order to improve the transmission efficiency of the system,it is very necessary to ensure that the system,especially the coil at the energy transmitting end,works in the resonant state in real time.Then,the frequency tracker is built in Matlab / Simulink circuit analysis software and verified by simulation.Finally,the paper designs a wireless charging system for electric vehicle,gives the design index of the system,and calculates and designs the main circuit parameters.In order to more truly simulate the electric vehicle wireless charging system,the simulation model of the electric vehicle wireless charging system is built in Simplorer,and the joint simulation is carried out combined with the coil model designed and calculated in Maxwell and the MATLAB / Simulink frequency stability control circuit to further verify the rationality of the coil design and the practicability of the frequency tracker. |
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