Research On High Frequency Wireless Power Transmission Technology Based On Intermediate Coil

The use of wireless power transmission technology can meet people's needs for portability and mobility,and it can make electronic devices have greater security and adaptability when used,so it is more and more accepted by people.In the field of power electronics technology,when the switching frequency is increased to megahertz,the volume of the inductor and capacitor is greatly reduced,so it is conducive to achieving the goals of miniaturization,integration and high power density of the switching power supply.Raising the frequency of switching power supplies brings many advantages,so the development of high frequency has broad development prospects.Under this background,this subject carried out research on the high-frequency wireless power transmission technology based on the relay coil.In order to obtain the accurate parameter design of Class E inverter,this paper uses the parameter analysis method of numerical analysis on the basis of theoretical derivation,which ensures that the switch tube can achieve the zero voltage conduction(ZVS)characteristic,reduce the loss,and improve the design speed and accuracy.At the same time,this paper analyzes and numerically calculates the working process of Class E resonant rectifier,and obtains the expressions of voltage and current of diode and equivalent input impedance of rectifier,which are used for the design of rectifier parameters.This paper builds a high-frequency wireless power transmission system based on Class E inverter and rectifier,and the experimental test results verify the rationality of the design method.In order to explain the energy changes that occur in the transmission process of the wireless coupling part,this study models and analyzes the circuit of the magnetic coupling transmission part of the wireless transmission system,and explains the transmission mechanism.According to the theoretical analysis,the equivalent models of two coils,single intermediate coil and matrix intermediate coil are established,and the design method of intermediate coil parameters is proposed.A prototype is designed and built to verify the theoretical analysis.Compared with enameled wire and litz wire,in the system with a frequency of up to megahertz,the planar PCB coil has a higher quality factor,so the loss generated is lower.In this paper,a planar PCB coil with a high quality factor is designed.On the basis of theoretical analysis,combined with finite element simulation to optimize the design,a PCB coil with high accuracy and high quality factor is designed to reduce losses and effectively improve system performance.In order to improve the load disturbance and improve the performance of Class E inverter,a T-type matching network is proposed for the output of the inverter to improve the stability of the system.The designed structure can effectively improve system performance.In order to improve load disturbance and improve the performance of Class E inverter,a T-type matching network is proposed for the output of the inverter to improve the stability of the system.This subject designs and builds an experimental prototype of a high-frequency wireless power transmission system based on a intermediate coil with a rated input of 15 V,a rated output of 5V/10 W,and an operating frequency of 6.78 MHz.The experimental test results are in accordance with the expected indicators.Under the rated load of the system,the working efficiency is higher than 70%.After comparison,the efficiency of the system with intermediate coils is higher than that without intermediate coils,and the offset resistance has been improved,which is consistent with theoretical analysis and simulation.