Design Of Wireless Charging System With Resonance And Informationg Transfer

Wireless charging technology uses the principle of electromagnetic induction to achieve energy transformation,which has the characteristics of no contact,no wear components and easy to use.Therefore,wireless charging technology has a wide application prospect in electronic products,electric vehicles,medical equipment and other fields.At present,though there are many companies have launched their wireless charging products.These products also have some shortcomings,like short transmission distance,low transmission efficiency,no information feedback,poor versatility,high prices and so on.Aiming at the above problems,this paper has a deep research on the wireless charging transmission and the information feedback.The specific content is as follows:Firstly,this paper makes some theoretical analysis on the energy transfer and information transfer of electromagnetic resonance.In the aspect of energy transfer,this paper analyzes the influence of system frequency,coupling factor,quality factor and coil radius on the transmission efficiency;In the aspect of information transfer,this paper analyses the concrete method of using modulation technology to realize the information feedback.The above analysis provides a basis for improving the transmission efficiency of the system and achieving the information transfer.Secondly,the simulation model of wireless charging system with information transfer based on different inverter circuit has been built on the MATLAB/Simulink platform.The correctness and feasibility of the designed system are verified by the simulation results,which laid the foundation for software and hardware design of the system.Thirdly,the software and hardware of the resonant wireless charging system have been designed in this paper.Hardware design include a power supply circuit,an inverter circuit(full bridge and half bridge),coupling coil,the high-frequency rectification circuit,lithium battery charging circuit,modulation and demodulation circuit.Software design include the operating frequency of system(PWM),voltage and current protection,information feedback with ModBus protocol and other related software.Finally,the built wireless charging system has been tested and the experimental results have been summarized and analyzed in this paper.The experimental results show that the transmission distance of traditional electromagnetic induction type is about one centimeter and the transmission efficiency can only reach 60%;The transmission distance of electromagnetic resonance can be increased to three to five centimeter and the transmission efficiency is about 55%～74%.The transmission distance and transmission efficiency are obviously increased.At the same time,the information feedback is realized by using the modulation and demodulation technology and the information after demodulation is complete and stable.