In this paper, a hybrid excitation synchronous machine (HESM) with brushless structure and controllable magnetic flux is proposed for ship propulsion, in which the field winding will be placed outside of the stator to provide an axial magnetic field travelling through a double-magnetic-bridge (DMB). In the proposed HESM, the rotor permanent magnet will provide the main flux while the field winding will provide a variable auxiliary flux, which can meet the ship propulsion system’s requirements in both large startup torque and wide speed range operation. The electromagnetic performance of the proposed HESM is evaluated by both the magnetic equivalent circuit (MEC) method and three-dimensional (3D) finite element analysis (FEA), which exhibits good capability in the control of magnetic flux. Besides, the temperature field analysis also shows that the temperature rise in the main parts of the proposed HESM will be within an acceptable range.

Hybrid excitation synchronous machine; magnetic bridge; magnetic flux regulation capability; 3-D FEA;