Feature investigation of axial flux leakage of a hybrid excitation synchronous machine

In order to reduce flux leakage in a hybrid excitation synchronous machine (HESM) with magnetic shunt rotor and optimize the design, the axial flux leakage characteristic of the HESM is investigated in this paper. The flux patterns and leakage flux distribution are analyzed by 3D-FEM. The influence of key parameters on the magnetic flux leakage characteristic is analyzed and the optimization principles are summarized. A precise 3D equivalent magnetic circuit network (3D-EMCN) is developed based on the analysis of the flux leakage characteristic and validated by the simulated and measured results of a 100-kW HESM. The difference of no-load phase back-EMF between 3D-EMCN considering leakage flux and 3D-FEM or experiments is below 8%, verifying the effectiveness of the proposed model and flux leakage analysis. Based on magnetic flux leakage characteristic and optimization principles, the structure of the HESM is optimized.