| The noise generated by the printed circuit board(PCB)of the charging pile will not only affect the work of the device itself,but also cause interference to the surrounding environment.Therefore,the electromagnetic compatibility(EMC)must be studied and optimized for the electric vehicle charging pile.This thesis used the finite element simulation analysis software Ansoft HFSS to establish the overall model including the chassis,the internal circuit of the chassis,and the PCB shielding box.Combined with Hyper Lynx and SIwave for EMC collaborative simulation design,the circuit-level electromagnetic interference was reduced by means of termination and decoupling.A shielding finger structure specially designed for the PCB shielding box of the charging pile was proposed and compared with an ideal electromagnetic shielding material,and the difference in shielding effectiveness between the two was analyzed.At the same time,metamaterial was researched,and metamaterial structure arrays were applied to PCB shielding box to further reduce electromagnetic radiation.The simulation results verified the proposed EMC optimization method.The shielding finger structure can replace the ideal electromagnetic shielding material and has a good shielding effect.The resulting comprehensive shielding design reduced the noise level by 16.4d B.The main work of the thesis is as follows:(1)Based on board-level EMC simulation tools ANSYS SIwave,Hyper Lynx,and system-level EMC simulation tool HFSS,an EMC design process suitable for this topic was designed and implemented,including board-level simulation,chassis model establishment and excitation source extraction,system-level simulation,and electromagnetic shielding design.(2)The PCB board-level EMC design of the electric vehicle charging pile was studied.In the electromagnetic simulation software SIwave and Hyper Lynx,the PCB was analyzed for inter-board resonance analysis,near-field radiation scanning,port current and radiation spectrum analysis,decoupling and termination experiments,and EMC processing was performed from the radiation source.The processed PCB simulation parameters were then extracted for subsequent collaborative simulation analysis.(3)The commonly used collaborative simulation design process was studied,and an EMC collaborative simulation process suitable for the research object of this thesis was proposed to systematically design the EMC of electric vehicle charging pile.Through theoretical analysis and simulation verification of several factors that affect the electromagnetic shielding effect of the chassis,the establishment of a charging pile model was guided.(4)The electromagnetic shielding design of the electric vehicle charging pile chassis system was mainly studied.A shielding finger structure designed specifically for the PCB shielding box of a charging pile was proposed.The effectiveness of the structure was analyzed and verified by comparison with the reference,and it can be a good substitute for ideal electromagnetic shielding material.Finally,by comparing and analyzing the relationship between the factors of the metamaterial array and the shielding effectiveness,the metamaterial structure was applied to the shielding box to complete the final comprehensive shielding design. |
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