At present, almost all hybrid excitation machines (HEMs) apply DC field current to control the air-gap flux. However, the DC field control mode results in a problem that the capability of field-weakening is not equal to
that of field-strengthening. This paper briefly explains the mechanism of asymmetric bidirectional field control capability in present HEMs, proposes a consequent pole hybrid excitation synchronous (CPHES) machine with AC field control mode to solve the asymmetric problem. The structure and principles of CPHES machine are presented. Additionally, the equivalent magnetic circuit model of CPHES machine is derived to reduce the computational complexity of analyzing CPHES structure by using three-dimensional finite element analysis (3DFEA). The proposed equivalent model and 3D-FEA are compared, the results verify the proposed model is basically consistent with the 3D-FEA, and the proposed model is able to reduce the computational complexity greatly.