A hybrid excitation machine with AC flux control winding

The air-gap flux in hybrid excitation machine (HEM) can be adjusted flexibly by introducing the auxiliary electric field windings. At present, almost all HEMs employ DC field current to control the flux linked with armature windings, where the bidirectional flux control capability of this structure is not symmetric. In this paper, the reasons of asymmetric problem in HEMs are analyzed, a novel flux control method and the corresponding topology are presented. Three-dimensional finite element analysis (FEA) verifies the flux control capability of this structure.