| Development of wireless power transfer technologies has intensified in recent years,and it is also becoming an important direction of future scientific research.This thesis analizes and designs the entire wireless power transfer system which is based on magnetic resonant coupling.The main topics include the designs and analyses of the transmitting and receiving coils,RF power sources,rectifier and voltage regulators.More specifically,this thesis first develops circuit parameters of the transmitter and receiver by using the coupled mode theory.A four-coil structure is presented and its advntanges are analyzed and demonstrated.HFSS is used to simulate and design the transmitting and receiving coils.The array configuration of the transmitting coils presented.Secndly,this thesis analyzes and compares the characteristics of various classes of power amplifier.The working principle of Class E power amplifier is described and its circuit parameters are optimized.A class E power amplifier is designed with Agilent ADS sat the operating frequency of 13.56 MHz.The simultaed power output is 20 W and the simulated efficiency is about 83.5%.In addtion,a 13.56 MHz frequency source is designed with a crystal oscillator and a buffer amplifier.Thirdly,this thesis proposes a bridge rectifier and a voltage stabilization circuit with a Buck voltage regulator.It can be used for charging mobile phones.Fourthly,prototypes are developed and tested.The scattering parematers of the coils are measured at the optimal power transmisstion distance with the RF power source output adjusted to 10 W.Furthermore,effects of vrious parameters,such the power transfer distance,coil orientations,obstacles in the ppower transfer path and the load,on the power transfer performacnes are studied and presented.In the end,this paper presents the future work including the adaptive power source and communications between the wireless power transmitter and receiver. |
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