Research On Dynamic Wireless Charging System For Electric Vehicles Based On Misalignment Tolerance

The rapid development of electric vehicles has led to a significant increase in ownership,yet existing charging methods cannot fundamentally address the problem of mileage anxiety.Dynamic wireless charging technology for electric vehicles offers a new way of thinking to solve the mileage anxiety problem.This technology enables charging while walking and can effectively reduce the battery capacity and improve the range of electric vehicles.However,there are various coil structures and compensation topologies that need to be evaluated for dynamic wireless charging.Moreover,the dynamic wireless charging process requires a large number of switching actions,which leads to frequent power dips.To address these problems,this paper takes magnetically coupled resonant dynamic wireless charging technology as the research object,based on the anti-divergence characteristics from the compensation network,coupling mechanism,switching strategy and other aspects,the main research content is as follows:1.A mathematical model of magnetically coupled resonant wireless energy transmission with LCC-LCC high-order compensation network is established and its transmission characteristics are simulated.The simulation shows that it has constant current characteristics and can ensure that the transmitter will not be short-circuited under large misalignment or noload.The simulations show that the LCC-LCC is suitable for use in dynamic wireless charging systems as it has minimal efficacy fluctuations in the presence of offsets.2.In order to determine the suitable coil structure for dynamic wireless charging,typical coil offsets were classified and compared using COMSOL finite element simulations.The simulation results show that both circular and rectangular coils are insensitive to tilt offset and that horizontal offset is the main influence.Although the mutual inductance of the rectangular coil is not as high as that of the circular coil,the mutual inductance fluctuates less in the case of horizontal offset,which means that it has better resistance to offset.3.The switching process of a collective dynamic wireless charging system is modelled and simulated using an electromagnetic transient programming algorithm.The results indicate that a hard switching strategy can lead to a dangerous surge in system voltage at the moment of switching,while a soft switching strategy can effectively reduce system shocks and protect system safety.The simulation shows that the dual coil power supply strategy can effectively reduce the mutual inductance and power fluctuation during the switching process and improve the stability of the system.The results show that in order to ensure the maximum transmission performance,the voltage phase of the primary side should always be consistent when the coil is switched,and the switching area is obtained to reduce the output voltage fluctuation.4.A dynamic wireless charging experimental platform is established based on the LCCLCC topology with rectangular coils.Based on the experimental platform,the constant current characteristics of the LCC-LCC topology are verified,experiments are conducted for the case of variable load and variable offset of the system,and the effectiveness of the proposed dual coil power supply strategy is verified.