Application Analysis Of Wireless Energy Transfer System About Portable Mobile Devices

In recent years,the wireless energy transfer technology has developed significantly due to its wide range of application scenarios and extremely high practical value.This paper aims to achieve the application of wireless energy transmission about portable mobile devices.Starting from the basic theory of magnetic coupling resonant wireless power transmission,the three parts of the wireless power transmission system—the transceiver coil module,RF power source,and the rectifier&voltage regulator circuit are analyzed and designed.Firstly,through the derivation of the coupled-mode theory,the paper concludes that the condition of the magnetic coupling resonance is that the operating frequency is equal to the self-resonant frequency of the transceiver coil.Through the derivation of the two-port network theory,the input and output impedancethat maximize theoutput power is obtained.The principle as well aspros & cons of various coil structures are analyzed and compared.A three-coil structure model that meets this design requirement is selected.Based on this structure,a HFSS simulation design is performed,and a transmission coil scheme using an overlapping array structure is obtained.In the entire horizontal plane at an optimal coupling distance of 5 cm,the transferring efficiency of the transceiver coil can reach 81.74%.The interference of metal stuffs to the transceiver system is briefly described,and the overcoming of the interference of the ferrite sheet on the metal interference is analyzed.In the RF power source part,the technical indicators and work categories of the power amplifier are introduced and analyzed.The class E power amplifier that meets this design requirement is selected,meanwhile the theoretical analysis and parameter calculation are performed.The power amplifier circuit is designed.The power amplifier’s input signal is provided by a 6.78 MHz crystal oscillator and the DC bias is provided by a DC buck circuit.In the design of the rectifier &voltage regulator circuit,through the introduction and analysis of the circuit principle,in the rectifier part,the bridge rectifier circuit is selected,and the Buck regulator circuit is selected in the regulator part.The output power can be used to charge mobile devices such as smart phones.Based on the above analysis and design,the PCB layout of each module was also plotted and produced.The system was tested and analyzed from the aspects of metal interference,coupling distance,and horizontal position,which proved the feasibility applying magnetic coupling resonance wireless power transmission system for portable mobile devices.At the end of the thesis,the overall work content is summarized,and the prospect of the follow-up work — adaptive power distributing,wireless energy-carrying communication and implantable receiver coil has been pointed out.