Design Of High Frequency Power For Magnetic Coupled Resonance Wireless Power Transfer System

Magnetic coupled resonance wireless power transfer(MCR-WPT)has the advantages of long transfer distance and high transfer efficiency.Since it was proposed,it has quickly become a research hotspot in the field of wireless power transfer technology.At present,domestic and foreign scholars have conducted studies on the working principle,circuit transmission structure,transmission coil design,the relationship between the intermediate coil and the efficiency,and obtained a lot of research results.However,there are few researches on the high frequency inverter which has important influence on the transmission characteristics and transmission efficiency of MCR-WPT system.To realize the efficient long-distance transmission of the MCR-WPT system,the high frequency inverter of the system is required to provide high frequency high quality AC power.However,the influence of the circuit parasitic elements at high frequency cannot be ignored,which brings challenges to the research and the design of the high frequency power.Based on SiC MOSFET,this thesis studies and designs the high frequency inverter of MCR-WPT system.First,compared the transmission characteristics of the two-coil transmission structure and the four-coil transmission structure of the MCR-WPT system,and combined with the practical application,the two-coil transmission structure was selected as the starting point of the design of the high frequency inverter in this thesis,and the ss-type resonant topology circuit model of the two-coil transmission structure was further established.On this basis,the efficiency and transmission power formulas of the MCR-WPT system are derived,the factors affecting the efficiency and transmission power of the system are analyzed,and the influence of parasitic parameters in the inverter circuit on the system efficiency is further revealed.Secondly,completed the design of high frequency inverter of MCR-WPT system.Aiming at the problem that the influence of parasitic parameters in the inverter circuit under high frequency operating conditions cannot be ignored,the influence of parasitic parameters on the inverter circuit under high frequency operating conditions and the causes of high frequency oscillation are analyzed in detail.The influences of device packaging and the printed circuit board(PCB)layout on circuit parasitic elements are studied.An optimized inverter PCB layout design that aims to reduce the parasitic elements and to provide a stable and high-quality AC power for the wireless power transfer system is presented.Finally,the experimental platform of MCR-WPT system was built.The dynamic process problems in the preliminary test were analyzed and solved.And experiment in the building of MCR-WPT system platform,under the working conditions of 900 kHz compared to the conventional PCB layout and the optimized inverter circuit PCB layout working performance,and FFT analysis is made on the measured data.Experiment and FFT analysis results show that the presented optimized inverter circuit PCB layout design not only reduces the parasitic inductance in the circuit,and reduces the electromagnetic interference noise,improve the inverter stability.Furthermore,a mobile phone wireless charging system based on the principle of magnetic coupled resonance is designed and built.