Modeling and Analysis of Superconducting Machine's Hybrid Damping and Shielding System

Damping and shielding system (DSS) is one of the key structures in the superconducting machines, which is used to provide damping for the machine to reduce the influence of the prime mover torque and electromagnetic torque fluctuation on the operation, and to shield harmonic magnetic field of the armature side to reduce the ac loss generated in the superconducting field winding. The method based on the traditional electromagnetic DSS will affect the damping performance when ensuring the shielding effect. At the same time, the size of the support structure needs to be increased in order to cope with the large failure torque, which would further increase the effective air gap of the machine, thus affecting the increase in power density. This paper proposes a superconducting machine hybrid damping and shielding system that combines mechanical damping and electromagnetic damping shielding system, which can provide sufficient damping for the machine on the one hand, and ensure good shielding performance on the other hand. The shielding performance analysis model of the DSS, the seventh-order state equation and Simulink analysis model of the machine when the mechanical damping is considered are established, and the transient fault response of the machine before and after the mechanical damping is compared. The result shows that the hybrid DSS can provide better shielding and damping effect for the superconducting machine.