| In recent years,Wireless Power Transfer(WPT)technology has become a hotspot because of its strong environmental adaptability,operational safety and other advantages.Dynamic Wireless Power Transfer(DWPT)technology is a promising project in electric vehicle charging,rail transit power supply and other related research fields.DWPT technology can effectively improve the cruising range of electric vehicles,reduce the capacity of on-board battery packs and reduce the cost of electric vehicles.Solving power supply accident caused by pantograph-catenary fault in rail transit.Dynamic Inductive Power Transfer(IPT)technology transmits energy through the electromagnetic field between the transmitter coils and pick-up coils.The stability of the system which aims at reducing power fluctuation is the key technical index of dynamic IPT system,which is directly related to whether the load device can work normally.The traditional method of using control circuits to improve the output stability of the system is difficult to implement and the reliability of the system is poor.Therefore,it is particularly important to study a dynamic IPT system with simple structure and stable output.Firstly,the principle of dynamic IPT technology is analyzed.Considering the system efficiency,loss and other factors,this paper adopts sectional track mode.By comparing and analyzing the traditional dynamic IPT system,a three-phase transmitter coils track coupling mechanism is proposed.Secondly,through the analysis of the asymmetric load of the threephase circuit,the advantages and disadvantages of the three-phase three-wire system and the four-wire system are compared.The electromagnetic coupling mechanism model of threephase dynamic IPT system is established.Thirdly,the influencing factors of the induced voltage of the pick-up coil are analyzed theoretically.A method of overlapping the transmitter coils is proposed to reduce the fluctuation of induced voltage.Maxwell finite element simulation software is used to optimize the overlapping degree.Finally,with the detailed derivation of the three-phase dynamic IPT system model,the expression of the system output voltage is obtained.The experimental results show that the dynamic IPT system with threephase power supply can effectively transfer energy.The proposed optimization method of overlapping transmitter coils can effectively reduce the fluctuation of system output voltage.Furthermore,the dynamic IPT system based on double pick-up coils is modeled and optimized.The electromagnetic coupling mechanism of double pick-up coils is taken as the research object to analyse the magnitude of induced voltage on different pick-up coils and its influencing factors.The effects of different connection modes between the pick-up coils on the system output are compared and analyzed.On this basis,the length of the pick-up coils is optimized to reduce the fluctuation of the system output.The dynamic IPT system model based on double pick-up coils is analyzed in detail and the output voltage of the system is derived.The experimental results show that the optimal design of the pick-up coils length can effectively reduce the fluctuation of the system output voltage and improve the system output stability. |
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