Research On The Electromagnetic Compatibility Technology For Marine Electronic Equipment

With increasing development of ship automation today, ship electronic equipment's catalogue, quantity and operating speed have been promoted constantly. At the same time, the electromagnetic environment in vessel has been worse than before. To ensure the safe navigation, ship electronic equipment should satisfy the requirements of electromagnetic compatibility. China has a high occupancy in shipbuilding field, but Chinese ship electronic equipment has a low occupancy in international ship market. As a core technology during the research and development course of ship electronic equipment, electromagnetic compatibility technology will affect the performance, cost and time to market of the product directly. Traditional R&D process followed a pattern of design-prototype production-test. If the test has not been passed, remedial measures even re-design would be needed, taking long period and expensive cost.EMC performance can be simulated and predicted using computer simulation technology early in the design course of the system. It helps to identify the key factor which impacting electromagnetic compatibility, and to provide direction and improvement target for the design engineer. As a result, a lot of design risk will be nipped in the bud, the R&D cycle will be greatly shortened and costs will be saved. The dissertation is supported by the research project "the research and development of the voyage data recorder". To bring the system-level EMC prediction for ship electronic equipment, electromagnetic field theory is employed. The systematic researches were done based on 3-D electromagnetic field simulation software. Main research methods and conclusions are listed below:(1) The theory basis of the EMC simulation about ship electronic equipment was studied. On the basis of comparing and analyzing numerical algorithms for solving the Maxwell equation, the TLM algorithm has been selected as the simulation and analysis numerical algorithm of the EMC for ship electric equipment.(2) Several common key problems about EMC was underlined and solved in this dissertation, which bring a series of conclusion for practical engineering. With 3-D electromagnetic field simulation software, conducted electromagnetic disturbance caused by common mode and different mode noise has been simulated and analyzed, based on which corresponding filtering strategy can be introduced. By simulating the electromagnetic radiation field of electronic equipment's heatsink, surface current of the heatsink was obtained. According to the surface current, the optimized ground connecting strategy of the heatsink was carried out. Also, by simulating the electromagnetic shielding effectiveness towards cases with hole or slot, shielding effectiveness of case with different shape, size and number of the hole or slot was studied, and the optimized hole or slot strategy of cases was obtained.(3) The suppression technique of a specific band of electromagnetic disturbance on the ship electronic equipment was studied, and several measures for inhibition of VHF-band electromagnetic harassment were obtained. By means of the 3-D electromagnetic field simulation software, the harmonic frequency shift technology of the cavity resonator was studied and obtained. Started from the shielding and absorbing, the suppression technology of electromagnetic interference was studied, the basic coupling rules between the excitation source and the box hole was received, and the optimization strategy of the absorbing material placement was obtained. On this basis, the electromagnetic interference suppression technology research of the ship VHF communications band was carried out, the box size, power line length and gap length in the formation of interference in the VHF band was analyzed, and the corresponding suppression measures was draw.(4) Using simulation technology to the EMC design of real ship electronic equipment, the VDR with independent intellectual property rights has been designed according the electromagnetic compatibility design requirements. Near field models of the VDR boards were set up, and the VDR system-level simulation model were established by importing the simulation results into the 3-D electromagnetic field simulation software as excitation source. Based on the simulation model, a wide range of EMC design VDR were compared and the optimal design was obtained. At last, the VDR passed all environment tests including EMC at a time, and obtained type approval by CCS, ABS, LR, PRS, RMRS, DNV and so on. Performance of the VDR has reached the international advanced level.