| With the rapid development of information technology,the electromagnetic field environment on ships is becoming more and more complex,which appears in the wider coverage band and higher power density.In addition to the strong magnetic field radiated by the power cable,the electromagnetic interference source on the ship includes the radiation field of the high-power phased array antenna and the instantaneous electromagnetic pulse emitted by the electromagnetic weapon.Under the excitation of high-frequency electromagnetic field,the wire inside the electric detonator is equivalent to the radio frequency cable,and the space field transmits electromagnetic energy to the key parts of the electric detonator through cable coupling,which causes interference.In addition,in addition to the low-frequency magnetic fields of power cables and high-frequency electromagnetic fields emitted by antennas and electromagnetic weapons,stealth materials widely used on ship platforms,such as coated absorbing materials and frequency selective surfaces(FSS),may excite high-order harmonics by power electromagnetic wave irradiation.When the frequency band of excitation source is rich,broadband noise may be caused,causing secondary interference to the cable and the electric blast device.This paper focuses on the above several electromagnetic compatibility issues,the main work includes the following aspects:(1)The method of calculating the magnitude of the low-frequency magnetic field radiated by the braided power cable is described in detail.Firstly,the 12-pulse rectifier and pulse width modulation(PWM)inverter are realized by electromagnetic transient simulation software PSCAD,and the actual current waveform transmitted by the power grid is analyzed.Then,based on the time domain finite element method,the near-end magnetic field and shielding performance of the power cable under different shielding conditions are estimated.Finally,the accuracy of the low-frequency magnetic field simulation model and calculation method of the power cable is verified by experimental tests.(2)Based on the equivalent circuit principle,the calculation method of maximum coupling power of bridge wire electric detonator under arbitrary frequency plane wave illumination is realized.The specific idea is to regard the feeding lead as a dipole antenna.The internal line and terminal of the electric tube are equivalent to the transmission line and the lumped element respectively.The method can evaluate the radio frequency safety performance of the bridge wire type electric blasting device in a high power electromagnetic wave environment.(3)Research on nonlinear characteristics of microwave segments for passive materials and active structures is studied.The nonlinear effect of passive materials is analyzed by simulation experiments.The extraction of nonlinear polarization coefficient of active metamaterials is realized based on nonlinear optics theory and experiment.For the passive structure,the effects of incident field strength,propagation distance,nonlinear polarizability and loss on the intensity of higher harmonics are studied.For the active structure,the diode-controlled switching FSS broadband absorber and reflector samples are processed.The second harmonic is observed by high-power electromagnetic wave irradiation experiment.The test data verified the validity of the derivation formula.The parameter extraction method can determine the nonlinear polarization characteristics of the active metamaterial and predict the high-order harmonic intensity that the metamaterial may excite under high-power electromagnetic wave illumination. |
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