| The mid-range magnetic resonant coupling wireless power transfer(MRC-WPT)technology uses alternating magnetic field as the medium of energy transmission,and can provide power to the receiver having the same resonant frequency in the effective coupling region,while other frequency-mismatched objects are hardly affected.It has the characteristics of omnidirectionality and selectivity.The existence of effective coupling region makes the setting of receiver more flexible and makes multi-load power 1 supply possible.Therefore,based on the mid-range MRC-WPT system,this thesis studies the effective coupling region and the load power supply in the region.First of all,the mathematical model of mid-range MRC-WPT system is established step by step from the coupled mode form of resonant coil by using the coupled mode theory.The transmission characteristics of the system are analyzed from the energy point of view,and the role of two key parameters in energy transmission is obtained:the magnitude of the coil quality factor determines the speed of energy decay and the coupling coefficient determines the speed of energy exchange between the two couplers.In addition,the key parameters such as transmission power and efficiency are obtained,which play an important role in the performance analysis and optimization design of the system.Next,in order to improve the flexibility of impedance matching in mid-range MRC-WPT system,the γ matching feed mode in microwave technology is applied to the coupling coil,and the coil with impedance matching function is designed.The relationships between the resonant frequency and the length,turn number,radius and turn spacing of the designed coil are analyzed,and the design method of the coupling coil is mastered.The experimental results show that the coupling coil with γ matching feed mode can match the internal resistance of the power supply,and has good application in the mid-range MRC-WPT system.Then,the effective coupling region is defined and its distribution in the first quadrant is explored from the perspective of mutual inductance.Based on the coupling coil with γ matching feed mode,the CMOSOL simulation model is established to simulate the energy transmission in the effective coupling region,and the effective coupling region is modified from the power point of view.At the same time,the reasonable range of the receiving coil setting is given.The simulation results show that the effective coupling point is related to the input impedance of the transmitting coil,and the effective coupling point can be improved by using the y matching feed mode of the designed coil.Finally,the effective coupling region is validated by the experiment platform of mid-range MRC-WPT system.The experimental results are in good agreement with the simulation results.In addition,the experiment of powering double loads in the effective coupling region is carried out,and its setting method has been preliminarily explored.The study of effective coupling region in this thesis has certain guiding significance for powering multi-load of mid-range MRC-WPT system. |
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