The Research For Conducted Interference Of Marine Power System

With the development of electronic technology in recent years, electric equipments aremore and more used in daily life, and especially in marine power system. The systemresponse efficiency and performance index can be raised efficiently by these equipment anddevices. However, plenty of electromagnetic noise power has been transmitted during thework of these equipment and devices, which could cause coupling propagation throughvarious routes, and that is electromagnetic interference (EMI). The existing ofelectromagnetic interference could reduce the performance of the system and equipment tosome extent, lead to work breakdown or even system failure. Therefore, in marine powersystem, reducing the system EMI and inhibiting the generation and propagation are necessarymethods to keep the normal work of the system and equipment. For effectively inhibiting theEMI in marine power systems to meet the electromagnetism compatibility standard, thetheoretical analysis and prediction calculation of EMI is necessary.Firstly, the background and significance of marine power system conducted interferenceprediction research are introduced, the relevant prediction method is proposed according tothe characteristics of the conducted interference. The research status of generation mechanism,modeling method, testing method and disturbance attenuation approach of conductedinterference is analyzed.After that, an conducted interference prediction method for marine power system isproposed based on the EMC theory and the research on the main coupling method of EMI.That is, analyze and determine the main interference sources and interference couplingchannels, build the equivalent parameters circuit, then interference prediction is achieved. Atthe same time, according to the analysis of conducted interference generation mechanism, thekey components in the system that produce and propagate the interference is figured out, andthe high frequency models of them are built for the conducted interference prediction.Finally, the conducted interference is predicted with the method of building theequivalent circuit that proposed previously using the model of three-phase frequencyconversion driving system and12pulses AC/DC system respectively. The conductedinterference in each system includes common mode and differential mode interference, andthe interference source, interference coupling channels and interference characteristics ofthem is different. So, after analyzing that, the equivalent circuit model of common anddifferential conducted interference are built and frequency domain analyzed. Matlab is used for simulation to get the conducted interference at line side. The simulation result coincideswith the previous analysis, which proved the availability of the prediction method.