Research On The Transmitter Power Supply In Dynamic Wireless Power Transmission For Electric Vehicles Based On Three-phase Coupling Structure

The dynamic wireless power transmission technology can realize the real-time supplement of electric energy during the driving process,thus increasing the mileage of the electric vehicle,reducing the configuration of the power battery,and overcoming the disadvantages caused by the traditional wired charging method.So it has important research value and is currently developing to High-power,long-distance,long-range directions continuously.Compared with a single phase system,The three-phase dynamic wireless power transmission technology has a large power level,a long transmission distance,and no fluctuation in the received power,which is bound to become one of the focuses of future research.However,there are also many problems that need to be solved,such as the complex mathematical model,difficulty in compensating the resonance,and the increase in control difficulty.Based on the above background,this paper studied the transmitter power supply in dynamic wireless power transmission for electric vehicles based on three-phase coupling structure.Based on the coupling mechanism of the three-phase I-type track DD receiving coil,a dynamic wireless power transmission system topology was proposed,a circuit model of the system was established,the impedance characteristics of the system were studied,and the decoupling of the three-phase transmitting coil was completed.The power characteristics and capacitance voltage constraints of the system were obtained.The expressions of voltage and current,resonant capacitance and input/output power of each part were derived.The correctness of the system topology and model establishment was verified by simulation.So it laid the foundation for system design and research on control method.Due to the influence of non-ideal factors,the received power during dynamic movement may fluctuate.It is possible to ensure that the received power is constant by adjusting the current of the track.This paper studied the method of adjusting the current of the track,improved the traditional square wave inverter method,analyzed the pulse density modulation(PDM)and duty cycle modulation.Two methods of duty cycle modulation,symmetry control and asymmetry control were studied theoretically.Theoretical waveforms of key nodes and commutation process descriptions were obtained.The advantages and disadvantages of the two methods were compared.It was proved that the asymmetric control method of the duty cycle could regulate the track current without increasing its switching frequency,which was verified through simulation.In order to apply the theoretical guidance of this paper,a set of three-phase dynamic wireless power supply system parameter design method was proposed,and this system was used as an example to complete the parameter design.A dynamic wireless power transmission three-phase power source was developed.Topological design,parameter calculation and device selection were performed for three-phase rectifier circuit and three-phase inverter circuit.A three-phase dynamic wireless power transmission system experiment platform was established.The system resonance matching was completed.The voltage and current waveforms of each node of the system were obtained.The correctness of the system topology,model establishment,control method and system parameter design method was verified by experiments.The research results of this paper provide a theoretical basis and practical solution for the practical application of three-phase dynamic wireless power transmission technology for electric vehicles.