干式变频变压器磁热力的计算与分析OA

The output transformer in the traction power supply system of maglev train usually operates at different frequencies.For assuring the operational reliability of this kind of transformer and analyzing the influence of fre-quency variation on its performance parameters,in this paper the magnetic-thermal-maehcnical properties of a dry-type variable frequency transformer under three operating conditions is studied.First,on the basis of measuring the magnetic characteristics of core materials at three frequencies,the magnetic field distribution,loss and short-circuit impedance under each working condition are calculated and compared by using the field-circuit coupling method.Then,the temperature distribution and hot spot temperature rise with or without harmonic influence are calculated respectively based on the finite volume method.Finally,the short-circuit performance is simulated and studied.The results show that the frequency variation has a significant effect on the core magnetic density,winding and silicon steel sheet loss and short-circuit impedance,the magnetic-thermmal-mechanical properties under the three operat-ing conditions meet the design requirements of the product and provide a reference for the development and design of dry-type variable frequency transformer in the future.