| With the rapid development of new energy industry,the wireless charging market continues expanding and the application of wireless charging becomes more and more extensive.The technology of MCR-WPT(magnetically coupled resonant wireless charging)has became more and more mature with the research results of many scholars,but the weak anti-offset ability of wireless charging system has been restricting the rapid development of wireless charging.In this paper,the offset characteristics of the wireless charging system are studied from three aspects: circuit,coil,and magnetic shield.The specific research contents are as follows:1)The influence of self-induction and mutual inductance changes on wireless charging circuits under coil offset is studied.Firstly,the circuit theoretical model and simulation model of LCC-S circuit compensation topology is established.Theoretical analysis shows that the efficiency and transmission power of the circuit system is affected by the coil offset;Simulation modeling builds a real model and analyzes the influence of the coil system offset on the system efficiency,transmission power,and inverter working state through parameter scanning.Finally,the influence of the coil system offset on the circuit system is obtained,which provides guidance for the coil system to optimize the anti-offset parameters.2)The influence of coil geometry parameters on the ability to resist offset is studied.In order to design a coil system with stronger anti-offset capability,it is necessary to study and analyze the influence of its geometric parameters on the offset capability.Firstly,a theoretical model is established,and the factors affecting mutual inductance are obtained by using the formula.Then the simulation software is used to model the single-turn coil and analyze the influence of coil shape and coil size on the anti-offset characteristics.Combined with the simulation results,it is pointed out how to design a coil with stronger resistance to offset.3)The influence of magnetic shielding structure on the coil system is studied.One of the prerequisites for strong anti-deflection capability is a strong coupling between coils.Magnetic shielding structures can enhance the coupling between coils.Firstly,a theoretical model is established to analyze the influence of magnetic shielding structure on the coil system.Then the influence of magnetic shielding structure on the coupling of the coil system is studied by using simulation software.Then through the offset test,it is pointed out that when the coupling is too close,the self-inductance of the coil will also change,and a region division method is adopted to distinguish self-inductance change and non-inductance change under the offset condition.4)This paper presents a switched multilayer multiple transmitting coil system.Aiming at the problem of the coupling area limitation of the anti-offset structure of the large transmitting coil and the small receiving coil,a switching coupling structure of the transmitting coil is proposed.The advantages of the new structure are compared through simulation analysis,and a mutual inductance detection method between coils is proposed to determine the number of transmitting coil with the maximum mutual inductance.5)Build an experimental platform.After the physical production of each module is completed,the DC power supply instrument is used as the power supply,the electronic load instrument is used as the load,and the power analyzer is used as the experimental record to build the overall experimental platform.According to the measured results,the minimum output power in the coupling area is greater than 70 W,the transmission efficiency is always greater than 80%,and the ratio of the maximum power and the difference between the minimum power and the maximum power in the coupling area is about 30%.The coupling area reaches 3/8 of the total area of the transmitting side,which is higher than 1/4 of the traditional anti-offset structure of a large transmitting coil and small receiving coil. |
PDF Full Text Request