Design and characterization of a concentrated winding based two-phase brushless exciter for aircraft wound-rotor synchronous starter/generator

The paper proposes an alternative method to design two-phase exciter based on the existing single-phase exciter to solve the excitation problem for the main generator when the aircraft starter/generator starts up. Compared with distributed winding, concentrated winding has been adopted for the exciter's field winding for the advantages of shorter end-windings and available space for air duct in the stator which really meet the demand of aircraft machines on volume and heat dissipation. Initially a reconfiguration of the existing single-phase exciter into a two-phase exciter has been carried out to assess the potential of the existing exciter. The relationship between the number of the field winding's turns of single-phase exciter and two-phase exciter has been analyzed, on the basis of which electromagnetic design has been accomplished using FEA. Simulation results verify the reasonability of the analysis and confirm that the two-phase exciter is capable of generating the required current both in the start and generation modes. Finally, the characterization of the two-phase exciter has been studied to supply excitation control with theoretical support.