Electromagnetic design of hybrid excitation synchronous machine with asymmetrically stagger permanent magnet

The structure characteristics and field control principle of a novel hybrid excitation synchronous machine with asymmetrically stagger permanent magnet (ASHESM) are introduced. The theory and method of electromagnetic design for ASHESM are investigated in detail. 3-D finite element analysis (PEA) is used to analyze no-load magnetic field distributions and air-gap flux per pole of the prototype for different field currents. A 1-kW 8-poles prototype is manufactured to verify the design method. The experiment for the field control capability of the ASHESM is carried out, which results coincide well with those of FEA. The experimental and FEA results indicate that the flux of this type of machine can be easily adjusted in a wide range with a relatively small field current and the machine shows higher efficiency.