Research On WPT System With Dual Resonant Frequency Switching And Information Transmission Technology Of Shared Channel

With the development of wireless power transmission technologies,more and more products have entered our lives.With the safety and flexibility of this power transmission mode,it has brought convenience to our lives.However,in practical applications,there are still some problems that need to be solved.The transmission of electrical energy often requires accompanying inf ormatio n transmission.In order not to add extra transmitting and receiving coils for constructing the information transmission channel,a shared channel type wireless energy and information synchronous transmission system is constructed in this paper.The system includes three parts,namely: dual resonance point switching wireless power transmission technology,half-duplex communication technology and coupling coefficient identification method.In wireless power transmission,a pair of transmitting and receiving coils rely on the principle of electromagnetic induction to realize power transmission that is not dependent on conductors.These two coils are called the magnetic coupling mechanism of the power transmission system.In order to reduce the fluctuati on range of power and efficiency,this paper proposes a theoretical method that uses multiple resonant frequencies to alternately perfor m power transmission.The high-frequency communication technology is introduced without affecting the stability of power transmission,and a coupling coefficient identification method is proposed to obtain the working state of the system.In the paper,the design principle of synchronous transmission technology of electric energy and information is firstly explained,and the system is divided into wireless power transmission part and information transmission part for theoretical analysis.In the construction of the power transmission system,the multi-resonant compensation structure is expanded and analyzed.The double-sided LCC compensation topology is used as an example to design a wireless power transmission system with multiple resonant frequencies.And two of the resonance frequencies are alternately used for power transmission within different coupling coefficient ranges.This paper presents the design methods of three types of wireless power transmission systems: constant current type,constant voltage type and hybrid type.At the same time,a complementary gain wireless power transmission mode is given as a follow-up design reference.Since the resonant frequency matching of the constant voltage output system is more complex and representative,this paper uses the constant pressure type as the experimental system for verification.According to the physical definition,the coupling coefficient of a couple of coil varies continuously from 0 to 1.In the experimental verification system constructed in this paper,when the coupling coefficient varies from 0.2 to 0.6,the minimu m transmission power is about 25% of the maximum transmission power,and the system transmission efficiency does not change by more than 3%.A single resonant frequency power transmission system only has the transmission characteristics of one resonant frequency in the system herein.Therefore,the dual-resonance-frequency-switching power transmission system described herein can reduce power and efficiency fluctuations to less than half of the existing design methods compared to a single-resonance-frequency power transmission syste m using the same pair of coils.This paper selects a shared channel half-duplex communication method for information transmission,and presents a parameter design method suitable for this dual-resonance frequency switching wireless power transmission system.According to the parameter design method given in this paper,the information transmission circuit and the power transmission circuit parameter design are independent.At the same time,according to the constraints on some parameters of the communication system,it can realize that the synchronous transmission of the power and the communication do not interfere with each other.Experiments show that the introduction of the communication system does not affect the power and efficiency of the power transmission.The half-duplex communication rate can reach 15 kbps.In the design of communication system,this paper further realizes the coupling coefficient identification function between system coupling mechanisms.According to the parameter design method given in the paper,the de tected voltage can be changed monotonically and approximately linearly with the coupling coefficient.Experiments show that this identification method can achieve the accurate acquisition of the coupling coefficient between the coupling mechanisms of the system without turning on the power transmission.