The research of radial structure HESM of magnetic shunting type

To overcome the voltage regulation difficulty of permanent-magnet synchronous machine (PMSM), a hybrid excitation synchronous machine (HESM) with the radial structure of magnetic shunting type was designed. The magnetic shunting was exploited to adjust the air-gap magnetic field of the HESM by adjusting excitation current. The paper describes the machine´s structure and principle. The concepts of the magnetic shunting point, the magnetic non-shunting point and the load balanced point were discussed. The air gap flux at magnetic shunting point and the magnetic non-shunting point were precise analyzed. The two-dimensional finite-element method (FEM) was exploited to count the positions of magnetic shunting point, the magnetic non-shunting point and the load balanced point. The theoretical analysis and experimental results show that the air gap flux of machine is lowest at magnetic shunting point and the air gap flux of machine is biggest at magnetic non-shunting point. The output voltage of machine can be kept constant by adjusting the excitation current when the power factor and the load changes.