| Magnetic Coupling Resonant Wireless Power Transfer(MCR-WPT)technology has the advantages of remoteness,safety,and convenience,and has a wide range of applications in new energy vehicles,health care,and mineral mining.With the continuous development of the consumer electronics field,the charging adaptation of each product is becoming more and more cumbersome and can only be charged by a single one.The demand for wireless power supply for multiple loads is also becoming more and more urgent.The key to multi-load MCR-WPT system design lies in reasonable coil design.At present,the research on multiload system is in its infancy,and there is no systematic multi-load coil design scheme yet.In addition,in the dual-load MCR-WPT system,there is a lack of systematic research on the structure of the receiving and transmitting coils,the determination of the coil inductance range,and the calculation of the coil inductance.This paper proposes a systematic design theory for dual-load MCR-WPT system coils.The main research contents are as follows:Firstly,the MCR-WPT theory is systematically analyzed,and four kinds of resonant compensation network structures,Sseries-Series(SS),Series-Parallel(SP),Parallel-Series(SS)and Parallel-Parallel(PP),are analyzed and simulated.Therefore,it is determined that the dual-load MCR-WPT system studied in this paper adopts the SS type resonant compensation network.In addition,electromagnetic analysis is carried out for three coil structures of circlecircle,rectangle-rectangle and rectangle-circle.Using Ansys Maxwell software to analyze and compare the magnetic field distribution strength of each coil structure and the transmission characteristics when the coils are offset,it is determined that the multi-load coil in this paper adopts a rectangular-rectangular coil structure.Secondly,the coil modeling of a dual load MCR-WPT system with rectangular coil structure is carried out.For the dual-load MCR-WPT system with rectangular coil structure,a method to determine the coil inductance range is proposed.The characteristics of this method are: 1)keep the two receiving coils the same;2)limit the inductance of the receiving coil to between 0.5 and 1 times the inductance between the transmitting coils;3)according to the circuit equation relationship between coil inductance and system power,efficiency and loop current,determine the range of coil inductance and lay the foundation for subsequent coil design.In order to determine the appropriate coil size within the inductance range,the coil inductance is calculated by the Finite Element Method(FEM)and the Greenhouse method,and the characteristic relationship between the coil inductance and the size and the number of turns is established.Finally,in order to solve the problems of time-consuming calculation of coil inductance by FEM,poor generalization ability and large error of calculation of coil inductance by greenhouse method,a calculation method of coil inductance based on Back Propagation(BP)neural network and FEM is proposed.The coil inductance can be obtained quickly and accurately,and the characteristic relationship between the coil inductance and the size and the number of turns can be constructed.According to the size relationship between the transmitting coil and the receiving coil,the inductance and size of the receiving and transmitting coils that meet the design requirements are obtained,and the design method of the dual-load MCR-WPT system coil that can quickly select the inductance and size is realized.Through the simulation analysis and experimental verification,the validity of the coil design method of the dual-load MCR-WPT system is proved. |
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