Research On EMC Evaluation Method Of System-level Based On Variable Weight Theory

The electromagnetic compatibility(EMC)evaluation of system-level is based on the EMC ebaluation between the devices within the system-level during the development phase.In order to forecast the EMC performance of the system in the function design stage,this paper deeply studies and realizes the EMC evaluation of the system-level based on the variable weight theory,and emphasizes on improving the method of determining the weight of indicators,which is universal and can be applied to other platform system evaluation of EMC.Firstly,by analyzing the types and characteristics of system-level EMC indicators,the network hierarchical structure is selected as the evaluation index system of system-level EMC.After analyzing the construction principles and steps of the index system and selecting the EMC index of the system-level,the evaluation index system of system-level EMC is constructed.The normalization methods of different index types in the EMC index of system-level are discussed,such as the proportion change method,interval number algorithm and triangular fuzzy number method.Next,according to the research of ANP method and entropy method,a decision approach based on preference is proposed to avoid the inconsistent judgment matrix of ANP method.Because the entropy method can not determine the index weights of interval numbers,which can be calculated by converting the judgment matrix to degree of separation matrix.A mathematical model for constructing ANP-entropy combination weighting is established,which makes the two weighting methods compatible.It analyzes the application of penalty variable weight,ncentive variable weight and mixed variable weight in variable weight theory to EMC evaluation of system-level.The formula for the transformation from constant weight to variable weight is determined by constructing the equilibrium function.Then,the advantages and disadvantages of FCE method and TOPSIS method are compared,and the TOPSIS method is selected as the evaluation method of the system-level EMC.The TOPSIS method is used to determine the weight of the index,and only the regular weight is taken into account.The TOPSIS method is improved based on the variable weight theory.Taking the four design schemes of HF radio as example,the evaluation results of the TOPSIS method are evaluated by ANP method,entropy method,ANP-entropy method and variable weight theory.Contrast evaluation conclusions,the method of EMC evaluation of system-level based on variable weight theory is validated.Finally,according to the evaluation method of system-level EMC proposed in this paper,evaluation software for EMC of complex system-level is developed.The software can be used to evaluate and analyze the complex system-level EMC in the design phase.