Simulation Study On Electromagnetic Interference Characteristics Of Platform Power Supply Network

The platform power network has the characteristics of large number of devices,complex network structure,concentrated coexistence of interference and sensitive devices.Compared with single equipment,the problem of electromagnetic compatibility of platform power network is more complex and severe.The research on the electromagnetic interference characteristics of the platform power network is beneficial to the optimization design of the electromagnetic compatibility of the platform power network.Therefore,for the platform power network,this paper obtains the transmission cable,load equipment and electromagnetic interference source model in the power network through theoretical calculation and experimental measurement.The platform power network model is established in the computer simulation software Multisim and the simulation analysis is carried out.The electromagnetic interference signals of typical measuring points are obtained.The validity of the model is verified by experiments.The main research results of this paper are as follows:(1)Based on the theory of electromagnetic field,the calculation methods of electromagnetic parameters such as resistance,inductance and parasitic capacitance are studied.The analytical expressions of electromagnetic parameters are obtained when two transmission cables are parallel to each other,when the distance changes and when there are other cables between them.The accuracy of the calculation results is verified by comparing the theoretical calculation results with the experimental measurement results;(2)For the load equipment in the platform power network,the input signal method is adopted to measure the impedance of the load equipment online.LabVIEW program is programmed to control signal acquisition and data calculation.The correction method of amplitude error and phase shift caused by the isolation measures in the experiment is studied.The on-line impedance characteristics of load equipment are obtained by experimental measurement and data processing.(3)Aiming at the EMI sources in the platform power supply network,the voltage source model is established,and the parameters of the model is measured.The amplitude and internal resistance of voltage source EMI source at several frequencies are obtained.The models of EMI sources in the form of voltage sources at different frequencies are established.The impedance parameter model of the platform power network is established;(4)The platform power network model including cable,load equipment and interference source is established.The EMI signal distribution in the platform power network is analyzed by simulation.The characteristics of the electromagnetic interference signal distribution in the platform power network are obtained.By comparing the simulation results with the measuredEMI signals,the effectiveness of this model is verified.The performance of low-pass Butterworth filter is studied by using this model.It is found that the performance of the filter is related to the impedance distribution at both ends.