Prediction Of Stranded Wire Electromagnetic Interference Noise Based On Multi-conductor Transmission Line Theory

Multi-conductor transmission lines,as the main channel for transmitting energy and signals,are becoming more and more dense with the high integration of modern electrical and electronic equipment and the increasing demand of systems for the transmission of massive data signals,leading to complex electromagnetic interference problems.Poor electromagnetic interference conditions can even endanger the stable operation of the system and cause some system functions to fail.Therefore,the electromagnetic interference problem of cables is a component of electromagnetic compatibility that cannot be ignored.Exploring the generation and transmission mechanism of cable electromagnetic interference noise,and predicting the magnitude of electromagnetic interference noise and the actual degree of harm,has important theoretical and engineering significance for the efficient operation of electrical equipment.At present,most of the research on cable electromagnetic interference is concentrated on uniform multi-conductor transmission lines,while the cables in practical problems are mainly non-uniform multi-conductor transmission lines.As one of the representatives of non-uniform transmission lines,twisted wires are widely used in various power equipment due to their extremely high anti-interference ability,which makes it difficult to predict the electromagnetic interference noise of cables in actual engineering.As one of the representatives of non-uniform transmission lines,twisted wires are widely used in various power equipment due to their extremely high antiinterference ability,which makes it difficult to predict the electromagnetic interference noise of cables in actual engineering.Based on the above considerations,this paper,based on the theory of multi-conductor transmission lines,carries out the research on the electromagnetic interference noise prediction of twisted wires,which mainly consists of the following research contents:(1)Based on the multi-conductor transmission line theory,the crosstalk prediction model and the field-body coupling transmission line model are established respectively.Derive the multi-conductor transmission line equations in the two cases and the solution process based on the chain parameter algorithm.Establish cable electrostatic field model and magnetic field model,use finite element software ANSYS to obtain electromagnetic parameters,and provide data support for electromagnetic interference noise prediction.(2)Build a multi-stranded wire model based on the solid geometry method.Through model analysis,matrix transformation and the introduction of backpropagation neural network optimized by the beetle antennae search algorithm based on chaotic disturbance mechanism(CDBAS-BPNN)to construct the stranded wire parasitic parameter extraction network.On this basis,the chain parameter algorithm is combined to solve the noise voltage and noise current.(3)A qualitative analysis of several important factors affecting the electromagnetic parameters of the cable is made through ANSYS simulation software.The CST simulation software is used to model and simulate the external electromagnetic field excitation,and predict the influence of electromagnetic interference on the load of the transmission line port by factors such as the incident direction of the plane wave and the height of the transmission line to the ground.The method of predicting the crosstalk of twisted wires and the electromagnetic interference noise proposed in this paper is verified by CST simulation.(4)A verification experiment for the prediction of stranded wire electromagnetic interference noise is carried out.Combined with a semi-anechoic chamber,a vector network analyzer ZVL3 is used to sweep frequency to extract the cable S parameters to propose cable crosstalk.The current probe BCP-512 and EMI receiver ESCI7 are used to measure the electromagnetic interference value of the transmission line under the external excitation field.Through the comparison of actual measurement data,the applicability of the method proposed in this article is verified.