Study Of Wireless Power And Information Transmission Technology Based On The Trapezoidal Current Waveform

Wireless power transmission technology has been regarded as one of the hottest research directions in modern power transmission fields.There have been many commercial applications using this technology in various fields,which shows its broad application prospects.However,in some special cases,wireless information is also needed to realize communication between transmitters and receivers.Therefore,a novel method based on trapezoidal current excitation which can realize wireless power and information transmission(WPIT)is proposed in this paper.The fundamental component of the trapezoidal current waveform is employed to transfer power,and its third-order harmonic component is selected to transfer information.First of all,based on the mutual inductance model,the basic composition,circuit principles and formulas of traditional wireless power transmission system are introduced.Reflected impedance is the main bond between primary circuit and secondary circuit.The research of it can help match the circuit parameters to improve the efficiency of power transmission.Then,a new solution to realize WPIT is proposed.Fourier decomposition method is conducted to establish the equivalent circuit model of the proposed system.By defining the triangularization rate of the trapezoidal current,quantitative analysis can be gotten to show the relationship of fundamental and harmonic components to different shapes of trapezoidal currents.Compared to the triangular current with the same peak current,the trapezoidal current waveforms can supply higher power.By changing the triangularization rate of the trapezoidal current,a dynamic control method of harmonic components for communication is achieved.The characteristics of the voltage envelope of the communication coil are analyzed.The selecting rules of the operating points are given based on the concrete calculation.Finally,hardware experiments platform is designed based on the equivalent circuit model and modem strategy to verify the correctness of the theoretical analysis.Experimental results show that the proposed method can effectively control harmonic components to reduce EMI noises,and the impact of communication function on the efficiency of wireless power transfer is extremely weak.Besides,the quasi-decoupling control between load conditions,communication function and communication speed can be achieved.