Reserch On Magnetic Integrated With Class-E Converter In Wireless Power Transfer Application

In recent years,magnetic coupled resonant Wireless Power Transfer(WPT)technology has been widely used in UAV(Unmanned Aerial Vehicle)wireless charging,industrial AVG car wireless charging,smart home wireless charging and other applications.Under certain conditions,increasing the operating frequency of the system is conducive to increasing the transmission distance and coupling transmission efficiency of the system.Therefore,the switching of inverter and the loss optimization of its magnetic components are helpful to improve the transmission performance of the system in different applications,so it has high research value and application prospect.The main research contents of this paper are as follows:Firstly,this paper introduces the basic structure of magnetic coupled resonance WPT system,and analyzes the advantages and disadvantages of each part of it.The class-E inverter with finite input inductance is proposed as the high frequency inverter.Since push-pull class E inverter has two input inductors,the inductors can be coupled or uncoupled.The design criterion of soft switch for push-pull class E inverter is directly influenced by the circuit design of different input inductance.In the existing literature,the derivation criterion of soft switch of push-pull class E inverter with uncoupled input inductance is the same as that of soft switch of single-tube class E inverter with finite input inductance,while the design criterion of soft switch of push-pull class E inverter with coupled input inductance is not clear.Therefore,in this paper,for the first time,the design criterion of soft switch is derived for push-pull class E inverter with input inductance coupling,which is convenient for further optimization of push-pull class E inverter.Secondly,push-pull class E inverter with finite input inductance has small input inductance.In the case that the input inductance is uncoupled,the current flowing out of the inductance has not only dc component,but also a certain amount of ac component.At the same time,discrete inductance components increase the volume of the system.In the design of high frequency converter,magnetic integration technology,can effectively reduce the amount of magnetic components and improve the output efficiency of the high frequency converter,so this article will focus on with limited input inductance of push-pull class E inverter input inductance,respectively puts forward the input inductance coupling case and input inductance of the uncoupled case integrated design of magnetic components,and puts forward the structure of the hybrid magnetic core magnetic parts design.Finally,This paper built a magnetic coupling resonant WPT prototype working at 3 MHz.Based on the integrated inductor design scheme of two kinds of different situations.Measured the inverter switch voltage,system transmission efficiency,input inductance of the harmonic current and magnetic components of hot like figure.The experimental results show that the hybrid integrated inductance coupling of magnetic core material makes the transmission efficiency of inverter reaches 87.1%,effectively suppress the harmonic current,has good application prospect and using value.