Research On Implementing Multiple Transmitting Coil For Wireless Power Transfer Via Coupled Magnetic Resonance

Wireless power transfer via coupled magnetic resonance is an innovational technology with high efficiency, non-radiation and good direction. It is suitable for middle-distance wireless power transfer, and it is a hot research spot at home and abroad in recent years. Currently, research work on wireless power transfer is mainly based in single transmitting coil. With the development of wireless power transfer and the increase number of transmitting coil, it has important theoretical significance and practical value to research wireless power transfer with multiple transmitting coils.Firstly, this paper analyzes the coupled mode theory, scattering matrix theory and circuit theory of wireless power transfer via coupled magnetic resonance. The results show that the circuit theory gives more intuitive explanation for wireless power transfer system’s electrical parameters and structure, also helps to optimize the parameters design of resonators.Secondly, a theoretical model of wireless power transfer with single and multiple transmitting coils is set up, the influence of variation of coupled coefficient and load on wireless power transfer is analyzed. The calculations provides optimal coupled coefficient and load under the maximum voltage conversion and maximum efficiency conditions, and the model is validated by simulation results.Then, a phase shifting method is presented to control the receiver voltage based on wireless power transfer with multiple transmitting coils. When the coupled coefficient and load changes, the voltage of receiver can be maintained by changing the phase difference of sources. Also, as this method does not require DC/DC circuit in the receiver, the cost of system is reduced.Finally, the experimental setup of wireless power transfer is established, including high frequency inverter, resonators, rectifying circuit and voltage acquisition circuit. Also, the performance of wireless power transfer with multiple transmitting coils is tested based on phase shifting method, and experimental results verify the characteristic of the system and the phase shifting method presented...