Temperature Field Analysis And Experimental Study For Permanent Magnet Coupler

Permanent magnet coupler is a non-contact transmission device with high efficiency,strong environmental adaptability and overload protection,which has been widely used in petrochemical,coal and electric power fields.The effective analysis for its temperature field is of great significance for realizing accurate temperature control,improving its service life,high efficiency and high reliability transmission,and also has important reference value for the research of high-power permanent magnet transmission technology.In this paper,a fast calculation method for eddy current loss based on equivalent magnetic circuit was proposed to realize the calculation of heat source of permanent magnet couplers.An analysis method of equivalent thermal network of permanent magnet couplers based on double feature plane was proposed to achieve accurate calculation of heat sources at key nodes The comprehensive performance test platform of permanent magnet couplers was built with 45 k W disk-type speed-regulating permanent magnet couplers as the experimental object,and the accuracy of the thermal analysis model established was verified.The specific research contents are as follows:(1)Aiming at the problem that magnetic field is highly nonlinear and heat source loss is difficult to calculate under the operation state of permanent magnet coupler,a fast calculation method for eddy current loss of permanent magnet coupler based on equivalent magnetic circuit was proposed.An electromagnetic analytical model considering air gap and magnetic flux leakage of permanent magnet was established to realize the rapid solution of eddy current loss of conductor,and the influence of slip,air gap,number of magnetic poles and other parameters on eddy current loss was investigated.The electromagnetic analysis model of the permanent magnet coupler was established by using the finite element method,and the eddy current distribution and internal magnetic field characteristics of the permanent magnet coupler were investigated,and the proposed analytical model of eddy current loss was preliminarily verified.(2)Aiming at the problem that the temperature field of permanent magnet couplers is difficult to be accurately characterized under the action of electromagnetic and temperature coupling,an analysis method of equivalent thermal network of permanent magnet couplers based on double feature plane was proposed.Based on the basic principle of heat transfer,the heat transfer modes between the structures were defined.According to the idea of concentrated parameters,the equivalent heat paths including radial and circumferential characteristic planes were established.The temperature iterative calculation was carried out,and the steady-state temperature was solved considering the magneto-thermal coupling.The finite element method was used to establish the temperature field analysis model,with which the temperature distribution was explored,and the influence of slip,air gap and heat dissipation on the temperature of permanent magnet coupler was analyzed.(3)The comprehensive performance test platform of 45 k W permanent magnet coupler was built,and the comprehensive temperature test was carried out.The output characteristics of the permanent magnet coupler were measured,and the eddy current loss model was verified.The steady state temperature measurement experiment of permanent magnet coupler was carried out based on infrared thermal imager,and the proposed equivalent thermal network model was verified.The results show that the relative error of the eddy current loss model is less than 7% when the slip ratio is less than 75% in actual working conditions.When the actual working condition slip ratio is higher than 75%,the relative error part is higher than7% and lower than 15%.The average temperature error value of each region of the equivalent thermal network model is less than 6℃,and the average error value of the conductor is less than 3℃.The effect of temperature on the transmission performance of permanent magnet coupler was analyzed by comparing the experimental data.