Medium-frequency transformer (MFT) is the core component of high voltage and large capacity DC converter

but high frequency and high power density can aggravate vibration noise of transformer. In order to accurately simulate the core’s vibration characteristics of MFT

a three-dimensional transient magnetic-structural field coupling analysis and calculation model of MFT is set up and the core’s vibration acceleration and displacement under no-load condition by using finite element method is calculated. The mechanical material parameters of nanocrystalline iron core are calculated and assigned in combination with the characteristics of the laminated structure of nanocrystalline rolled iron core and in accordance with the transversely isotropic. Both simulation model and true model of shell-type and core-type MFTs with different core topologies are set up

and the influence of air gap structure and core topology on the vibration of MFT is systematically studied by simulation and experiment. It is proved through the comparison of theoretical calculation and experimental results that the Maxwell force on the air gap surface of the core is the main cause of vibration

and the maximum Maxwell force density of the shell-type MFT (25 257 N/m

2

) is larger than that of the core-type MFT (20 936 N/m

2

). The maximum acceleration of shell-type (40 m/s

2

) is larger than that of core-type (30 m/s

2

)

and the numerical simulation error is within 10%.