A Single-phase Single-stage AC-AC Resonant Converter For Wireless Power Transfer System

Regardless of whether it is in industry or in daily life,wireless energy transmission technology(WPT),due to its convenience and forward-looking,the popularization and application of this technology will bring a lot of convenience to the society.The current wireless energy transmission technology can be classified as inductive coupled,resonant coupled and radiation field.Magnetically Coupled Resonant Wireless Power Transfer using the non-radiative energy generated has been widely used in actual applications with the advantages of middle transfer distance.However,the transmission efficiency of the magnetically coupled resonant wireless transmission system is easily affected by the parameters of the magnetic coupling mechanism.Additionally,there are mutual dependencies between magnetic coupling mechanism parameters and the operating characteristics of excitation source.Meanwhile,the development of the ac source of WPT is currently limited to the traditional inverter.The design and implementation of the primary side power converter are of great importance in Wireless Power Transfer(WPT)system based on magnetic coupling.The power converter comprised of rectifier and high frequency inverter used in conventional WPT system is comparative complicated in structure and control.In order to further observe the problems mentioned above,the work of the paper is arranged as follow:Firstly,in order to design the WPT system orderly and organized,a series-series equivalent circuit is built,and concludes the relationship between the operating frequency,system efficiency and the output power.It can guide the subsequent design of key merits.Secondly,a single-stage ac-ac resonant converter integrating bridgeless PFC rectifier with half bridge converter is proposed to improve efficiency by using only two switches,achieve high PF through parameter design,and keep the DC link voltage in a reasonable range.Furthermore,zero voltage switching(ZVS)of the power switches reduces the switching power losses.Thirdly,based on the effect of the value of the duty cycle on the operating status of the system,the time domain solution is analyzed using Laplace transform analysis,and the ranges of duty ratio is presented.Finally,an experimental prototype of rated power 60 W with the wireless power transmission distance of 15 cm is built.