| Non-contact power transfer is an epoch-making energy supply mechanism which can avoid troubles caused by messy cables in traditional plug-in charging systems.The conventional wireless power transfer system can only transmit the power in a signal direction.With increasing demands of realizing the power transmission for multiple devices in different positions,the omnidirectional wireless power transfer technology has attracted more attention and has been widely studied.The omnidirectional wireless power transfer system is able to transmit the power to the receiver at arbitrary positions,which generally consists of an orthogonal transmitter and a single-coil receiver.However,the uncertainty of the spatial position and attitude of the appliances can still result in the misalignment in the system,which will greatly affect the transmission performance.Due to the orthogonal relationship between the transmitting and receiving coils in some specific regions,the corresponding mutual inductance tends to disappear,namely incomplete coupled effect,which will cause the deterioration of the transmission performance.Besides,the selfrotation of the receiver can lead to the angular misalignment between the transmitter and receiver.The transmission performance will also have an obvious decrease when there exists a large angular misalignment in the system.Therefore,it is also sensitive to the angular misalignment.In this paper,a quadrature-shaped receiver design is proposed in order to optimize the performance of omnidirectional wireless power transfer in 3-dimensional space.Firstly,the key parameters are the length and width of the central crossed structure,which are obtained by theoretical derivations.Their optimization analysis is also carried out by simulation,which demonstrates that the transmission power can be effectively improved with the increase of either length or width while the system efficiency tends to decrease.Then,its compensation of the incomplete coupled effect is revealed by using the equivalent circuit.Besides,the electromagnetic theory is utilized to clarify how it restrains the angular misalignment sensitivity.Finally,the simulated and experimental results are both carried out,which illustrates the proposed design can obviously improve the transmission power at incomplete coupled positions.The comparative results also verify that the quadrature-shaped pickup can effectively stabilize the performance when there exists angular misalignment along three directions.Therefore,the proposed pickup topology is able to optimize the system performance in3-dimensional space,which provides the theoretical basis and technical solution for the in-depth study and development of omnidirectional wireless power transfer technologies. |
