| Wireless Power Transmission technology has been paid more attention both in research and commerce field.The existing wireless charging products based on the Qi standard can only achieve short-distance and fixed-point power transfer,and are not suitable for multi-dimension-free wireless power transfer applications.Based on the magnetically coupled resonant WPT technology,this paper discussed the design of compensation network,high frequency inverter and the magnetic coupling system of the WPT system.And a new solution for the Multidimensional-freedom WPT system is proposed.First of all,the resonant compensation network has an important influence on the key performance such as efficiency and gain of the WPT system.In this paper,the structure and parameter design method of the existing resonant compensation network were summarized and unified based on the transformer T network model of the magnetic coupling system.The structure and parameters design method of any constant voltage/constant current output compensation network based on the leakage inductance compensation are proposed and analyzed.The LCC/S compensation network was detail analyzed based on which the current of transmitter coil is load free and compensation parameters of the receiver coil is mutual inductance free.And the advantages were summed up,such as the inverter current can be effectively reduced,constant voltage source output,the voltage gain is high and the compensation network is easy to be adjusted,etc.A Kf design method is proposed,which takes the influence of the frequency,coupling coefficient and transfer efficiency of the WPT system into consideration.It reveals the common of the resonant WPT systems at different frequencies,by which the performance of the system can be improved.Secondly,as the main power transfer component of the WPT system,the magnetic field can be controlled by the current of the transmitter coil.Changing the amplitude,frequency and phase of the current of transmitter coil,the magnetic field can be controlled.Based on electromagnetic FEA simulation,the magnetic field distribution characteristics of two-dimensional quadrature coils can be got.It showed that the two orthogonal transmitting coils can generate the symertric magnetic field along the central axis of the quadrature coil when passing through the current with the same freqneycy,same phase and same magnitude.Based on which the phase shift control and micro-frequency-shift control scheme are proposed.They are especially suitable for a multi-demision-free WPT system.Thirdly,the design of high-frequency rectifier bridge circuit was introduced.Then in order to cooperate with the proposed magnetic coupling system scheme,a wide load modulation E-class power amplifier is proposed as an excitation source for the WPT system.The simulation analysis and compar:ison of the difference between the wide load modulation E class amplifier and the traditional standard Class E amplifier were done.The wide load modulation E class power amplifier can achieve soft-switch from the rated load to no-load.And the stability of the system can be improved.Simulation results verified the theoretical analysis to be correct and useful.Finally,the prototype experiwments verified adjustable constant voltage and constant current compensation network based on the leakage inductance compensation and its frequency shift characteristic and winding resistance influence to be correct.Then a wide load modulation class E power amplifier prototype was designed and manufactured to achieve ZVS from the load 11? to no-load range.The efficiency is about 88.5%under rated conditions.The WPT system based on wide load modulation class E power amplifier,LCC/S compensation network and two orthogonal transmitting coils was constructed,which verified the conclusions that transmission coil through the same current transmission has dead zone and micro-shift frequency scheme can improve the freedom of WPT system. |
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