| Contactless traction power supply system is a kind of equipment that use radio energy transmission technology to transfer electric energy from traction substation to rail transit vehicle.The operating principle of the contactless traction power supply system has the advantages of non-direct contact,no abrasion,and low maintenance cost compared with the traditional methods with the third rail or catenary.Therefore it has much potential to the application in the electrified railway,especially the high-speed and magnetic suspension railway.As an important index of contactless traction power supply system,excessive electromagnetic radiation not only affects the normal operation of the equipment around th e system,affecting the safety of driving,but also has effect on the health of personnel in the rail transit environment.As the core part of contactless traction power supply system to realize wireless transmission of electric energy,electromagnetic cou pling mechanism is directly related to the power transmission efficiency and external electromagnetic radiation level of the system.In order to ensure the transmission efficiency of electric energy,and to reduce the electromagnetic radiation of the syste m,this paper has taken analysis on the optimal design of the electromagnetic coupling mechanism of the contactless traction power supply system.This paper firstly introduces the economic value and related technical background of contactless traction power supply technology.Combined with the purpose of this study,this paper focuses on collecting and analyzing electromagnetic safety standards,from which it summarizes the electromagnetic radiation level evaluation standard of the system,providing suitable standard and basis for subsequent optimization effect of quantitative comparison.Secondly,this paper introduces the source and generation mechanism of the electromagnetic radiation from the system connected to Maxwell equations.In addition,it compares and analyzes the electromagnetic radiation level from each component of the contactless traction power supply system,making the conclusion that the main reason of the electromagnetic radiation is the magnetic leakage of the electromagnetic coupling mechanism.Then,the transmission efficiency model of the electromagnetic coupling mechanism based on LCLS compensation has been derived in this paper utilizing the uncompensated electromagnetic coupling mechanism mutual inductance model.To reduce the electromagnetic radiation of the electromagnetic coupling mechanism when the parasitic resistance of the fixed coil,the mutual inductance between the primary and secondary sides of the system needs to be increased as much as possible.It is important to determine the turns,shape of the coil and the permeability of the surrounding magnetic medium to reduce the electromagnetic radiation of the electromagnetic coupling mechanism in theory.Maxwell simulation platform is used to conduct finite element simulation analysis of the electromagnetic coupling mechanism.The effects of different coil structures,different core shapes and different shielding materials on the mutual inductance of the primary and secondary sides has been obtained as well.Moreover,based on the mutual inductance model and software simulation,a shape coil of “日” style with segmented guide rail power supply is proposed in this paper,and the electromagnetic radiation and mutual inductance in different combinations have been compared and analyzed.A magnetic core scheme using circular amorphous alloy is also presented,and the comparative analyses of the influence of core thickness and installation position on mutual inductance have been carried out.A shielding scheme based on aluminum plate is proposed,while the edge effect of shielding material and the influence of thickness and installation position of shielding material on mutual inductance and electromagnetic radiation are studied and analyzed.In addition,combined with the cost in the engineering practice,the turns of the primary side coil with the largest coil laying amount is reduced by 73%,and the material cost is reduced by about 70%.Meanwhile,the electromagnetic radiation of the electromagnetic coupling mechanism still meets the sta ndard requirements.Finally,according to the optimized model of the electromagnetic coupling mechanism,in order to verify the effectiveness of the optimization measures of the electromagnetic coupling mechanism,a contactless traction power supply system experimental platform is built in this paper to measure the electromagnetic radiation in the surrounding space.The experimental results are basically consistent with the simulation analysis,which verifies the correctness of theoretical analysis and the simulation analysis. |
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