Research On Large Coupling Ranges Of Wireless Power Transfer System Based On Reconfigurable Resonant Tanks

Wireless charging technology based on wireless power transfer technology(WPT)is a revolutionary automated charging technology.Electric vehicle wireless power transfer technology can be perfectly combined with autonomous driving technology,and it is an important basic technology to promote the popularization of electric vehicles and achieve the goal of "carbon neutrality".In this paper,the following researches are carried out on a wide-coupling range fixed-frequency wireless charging system with reconfigurable resonant topology:This article first proposes a concept of reconfigurable resonator based on split coil structure and introduces its basic working mode.The proposed reconfigurable resonator can integrate the characteristics of two-coil,three-coil,and four-coil WPT systems into one WPT system through switching and connection of operating modes,so that the WPT system with fixed frequency can output the required rated power in a very large coupling range.On this basis,this paper proposes a single-side reconfigurable topology of three-coil WPT system,do the actual circuit design for it,and analyzes all the working modes one by one,and theoretically deduce the connection conditions and parameter design methods of each mode.Through simulation and experiment,it is verified that the three-coil WPT system with single-side reconfigurable topology can meet the output power requirements of wide coupling range at a fixed operating frequency.Based on the proposed reconfigurable topology concept,this paper further proposes a double-sided reconfigurable topology of four-coil WPT system;through the switching of two single-pole double-throw switches,the system has “one-to-one mode”,“two-to-one mode”,“One-to-two mode” and “Two-to-two mode”.Theoretically derived the coupling range of the output rated power of the four operating modes under the limitation of the volt-ampere capacity.By simulating the system through the Ansys,the coupling range covered by the four operating modes can be well connected to each other,which greatly expands the total coupling range covered by the system.On the 3.3k W experimental platform of an electric vehicle,the rated power can basically be transferred between 40 mm and 215 mm at a single-side reconfigurable topology of three-coil WPT system,which is far beyond the coupling range of 175 mm to 215 mm under the traditional two-coil structure,and the efficiency is basically above94%.A double-sided reconfigurable topology of four-coil WPT system,which can transmit rated power in the range of 95mm-215 mm air gap,and the transmission efficiency of the overall coupling range is basically above 92%.Compared with the previous scheme,this scheme reduces a large number of additional compensation components and switches,and has higher engineering application feasibility.