Research On Electromagnetic Interference Modeling And Noise Suppression Methods Of Ship High-power Inverter Power Supplies

With the widespread application of electrical and power electronic components in ship systems,a great deal of Electromagnetic Interference(EMI)noises are generated,and affect the normal operation of ship power supply and distribution systems of sensitive equipment.As a carrier of electric power exchange between DC and AC power supply,high power inverter is an important source of electromagnetic interference noise in ship power supply and distribution system.In view of the above problems,this thesis gives an insight of the electromagnetic interference modeling of high power inverting power supply and noise suppression,the main contends are as follows:1.Based on the classification of EMI,the mechanism of conducted EMI noise generation in inverter circuit is analyzed.The circuit simulation model of ship high power inverting power supply is established in Simulink simulation environment.With the analysis of CM and DM conducted EMI noise,the input and output voltage noise of the inverter with IGBT as the power switching device are extracted,double closed loop control parameters of internal current loop and external voltage loop are modified to suppress conducted EMI noise.In addition,the extracted output AC voltage noise is separated and it is found that the conducted noise of the circuit is dominated by the CM noise.The impedance of the noise source is extracted by using the scattering parameter method.An EMI filter is designed to suppress conducted EMI noise.2.The mechanism of radiated EMI noise generation in inverter circuit is analyzed.Base on the analysis of the common mode and differential mode EMI noise,the method using fast Fourier transform is proposed to seperate CM and DM radiated EMI noise.The effectiveness of radiated EMI noise separation method is verified by experiment.In addition,the causes of typical radiation noise are analyzed,and a radiation noise model caused by impedance mismatch is established.3.Under the CST simulation environment,the inverter cabinet is modeled,and the effect of cabinet electromagnetic shielding under different cabinet models is also analyzed.The simulation results show that the shield efficiency of the back-hole opening cabinet is better than that of the bottom opening by 4.15dB.After position of opening is optimized,the simulation of different opening shapes is compared.The result indicates that the shielding effectiveness of the hexagonal opening is better than that of the circular opening and the square opening.After the model is optimized to be a regular hexagonal hole,the simulation results show that the addition of the shielding layer can optimize the shielding effectiveness of the cabinet by 7.63dB,which greatly improves the electromagnetic characteristics of the cabinet.4.The ship high-power inverter EMI experiment and noise suppression experiment are carried out.The conducted EMI noise is suppressed by adding filters to isolate the noise source.After the inverter power cabinet opening location,opening shape,shielding material selection are optimized,the purpose of suppressing radiation EMI noise of inverter cabinet is achieved.The EMI standard test of CE102,RE101 and RE 102 based on GJB151B are carried out on the optimized ship inverter cabinet.The correctness and effectiveness of the noise suppression method are verified.