| The dynamic wireless charging system of electric vehicles studied in this paper uses magnetic inductive coupling power transmission technology to provide real-time power supply for electric vehicles in the process of moving.Using this technology,electric vehicles need not parking to charge and the number of batteries carried can be reduced.In this way,the safety and the convenience of endurance mileage and power supply were improved.However,due to the lack of physical connections and the offset between the transmitter and the receiver during the charging process,the transmission efficiency of the dynamic wireless charging system of the electric vehicle is not high.From the two aspects of the resonant compensation structure and the coupling structure,this paper focused on the method of improving the transmission efficiency and the anti offset characteristics of the dynamic wireless charging system of the electric vehicle,aimed at the stability of the output power.Firstly,the system parameters affecting the transmission efficiency were studied,and the mutual inductance calculation model related to core property,core thickness,coil turn number and coil diameter was established,which layed a theoretical foundation for the next research.Secondly,aiming at the problem of large leakage inductance in the system,a bilateral LCCL resonant compensation structure was designed.Matlab was used to simulate the dynamic wireless charging system of electric vehicle using the resonant compensation structure.The simulation results showed that the transmitter could keep the stable excitation state,the equivalent impedance of the receiver met the pure composition.Thus,a bilateral LCCL resonant compensation structure could enhance the transmission efficiency of the traditional type dynamic wireless charging system.Then,in view of the poor anti offset characteristics of the existing electric vehicle dynamic wireless charging system,a double pole double cross half encircled rectangular coupling structure was designed.The simulation analysis of ANSYS Maxwell proved that this structure improved the coupling effect,anti offset ability and electromagnetic compatibility of the traditional type coupling mechanism.Finally,an electric vehicle dynamic wireless charging experimental system with a frequency of 30 k Hz,an exciting current of 40 A and a transmission distance of 150 mm was built.The experimental results showed that when the phase difference of the excitation sourceadded to the two coil of the transmitter was 180 degrees,the flux density distribution on both sides of the coil was the most concentrated;When the load changed from 10 to 40,the fluctuation range of output power was stable within 10%;The output power of the receiver could reach 4.6k W,and the coupling efficiency of the system was about 60%,which achieved the design index of the dynamic wireless charging system of the electric vehicle. |
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