| Inductive power transfer(IPT)technology has attracted widely attention all over the world,due to the advantages of safety,convenience,etc.However,the low coupling coefficient of the electromagnetic coupling mechanism has become a major bottleneck which restricted the transmission efficiency in the development of IPT technology.In order to increase the transmission distance and improve the efficiency and transmission power of the IPT system,the circuit model of the IPT system is built and the spatial characteristics of the electromagnetic coupling mechanism is studied.In addition,as for the typical planar coil and the traditional helix coil,the influence of mutual inductance and coupling coefficient of the electromagnetic coupling mechanism on the system efficiency and transmission power is established.As for planar coils,firstly,this thesis calculated the self-inductance and mutual inductance of the circular Archimedean spiral coil without any shielding to find the key parameters affecting the coil inductance.In addition,keeping the inductance parameters constant,the offset sensitivity of the three types of coil pitch with different coil sizes are proposed,and the finite element analysis software is used to compare and analyze the magnetic field distribution characteristics.Secondly,a square planar spiral magnetically coupled coil structure with a center tap is designed for the requirements of different output power levels based on the design of the magnetic coupling coil inductance parameters.The inductance parameters of the coil structure are changed by switching the taps of the coupling coil,so as to achieve a variety of output power level switching.For the traditional helix coil with compatibility,the magnetic circuit of the electromagnetic coupling mechanism was studied based on the bilateral symmetric coil.Combining with the simulation results,the influence of self-inductance of the coil with two windings,mutual inductance and coupling coefficient of the electromagnetic coupling mechanism with structural characteristics were analyzed.This thesis proposes an improved bilateral asymmetric magnetic coupling coil based on the structural characteristics of the bilateral symmetric coils.This structure can not only extend the compatibility of bilateral symmetric coil,but also avoid the zero-induction when the primary and secondary coils are aligned,which improves the corresponding mutual inductance and coupling coefficient,increases the transmission efficiency of the system.In addition,the two surfaces of the improved coil are analogous to the typical planar coils.The offset characteristics of the modified coil and the two planar coils are compared in an electromagnetic mechanism with the metal shield.At last,as for planar coils,this thesis made circular planar spiral coils with different spacing distance to verify the rationality of the simulation study.Then,the experiment platform of the IPT system was set up,two power levels of 500 W and 1.1kW were worked by switching the taps of the coils,which verified the validity and feasibility of the design.Finally,for the traditional helix coil,the experimental results were performed based on the experimental platform of the IPT system by making the improved coil and the bilateral symmetric coil structure.In addition,the offset experiment using the improved coil and the analog plane coil verified the effectiveness and advancement of the improved bilateral asymmetric coil. |
PDF Full Text Request