| Electric vehicle has been rising in recent years because of their environmental protection,stability and intelligence,but their energy replenishment methods and efficiency are slightly unsatisfactory.There are some disadvantages such as low efficiency and electric shock in plug-in charging,so it is possible to apply wireless charging technology to electric vehicles.In this thesis,a multi-physical field coupling simulation model is established for the medium-large power wireless charging system under the electric vehicle scene.The characteristics of electromagnetic distribution and electromagnetic shielding technology in its working state are studied.The optimal design of transmission efficiency and shielding effect is realized by orthogonal optimization method.At first the thesis reviews the current research status of the wireless charging system and its shielding technology,compares and analyzes the existing problems on the electromagnetic compatibility research of the wireless charging systems,and clarifies the research purpose and significance of this thesis.Secondly,the two components of compensation network and magnetic coupling mechanism in wireless charging system are researched.The advantages and disadvantages of mainstream compensation network and coil structure of magnetic coupling resonant wireless charging system are compared and analyzed.The resonant circuit and magnetic coupling mechanism suitable for wireless charging of electric vehicles are selected.Then the electromagnetic environment of the wireless charging system was researched,and the electromagnetic shielding phenomenon,parameter calculation and electromagnetic security problems were analyzed.Based on this study and compare different electromagnetic shielding strategies,the reactive resonance ring shielding strategy is proposed,and deduced the action mechanism of this method in detail.Moreover,the resonance mechanism of the LCC-LCC compensation topology was studied,the corresponding impedance matching and electric steam were completed,meanwhile the magnetic field distribution and transmission characteristics of the model were analyzed.The effectiveness of passive shielding and resonance ring shielding was verified.The shielding requirement completes the optimized design of the shielding module in terms of structure and parameters.At the same time,this thesis adopted orthogonal optimization method to constrain the resonance frequency and load power,and takes the transmission efficiency and shielding effectiveness as the optimization goals,and optimizes the design of the shielded wireless charging system,a complex system with multiple coupling,nonlinearity and multiple factors.,Obtained the influence trend and weight of the key factors in the system on the test indicators.Compared with the optimization before the system efficiency increased by 2% and the shielding effect increased by 59.62%.Finally,this thesis adopted the orthogonal optimization method to optimize the design of the wireless charging system with shielding device which is a multi-coupling,non-linear,multi-factor complex system.The influence trend and weight of the key factors in the system are obtained.Compared with the system before optimization,the system efficiency is increased by 2% and the shielding effect is increased by 59.62%. |
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