Mixed-pole hybrid-excitation machine

This paper presents the concept of a novel hybrid-excitation machine. This machine is of the parallel excitation type and has rotor poles in which both PMs and wound-excitation co-exist to produce the total no load magnetomotive force; for this reason it is named mixed-pole hybrid-excitation machine. Due to its parallel excitation nature, the machine has excellent flux linkage regulation properties and its use is therefore envisaged for applications that require wide constant power speed ranges. A very useful property that stems from this particular topology is that the designer is able to select the relative contributions of PM and wound-excitation flux by simply designing the relative portions of the PM part and wound-excitation part of the rotor poles. Although both radial flux and axial flux versions can be designed, this paper concentrates on the latter type. A proof-of-concept prototype is designed for a 600-6000 rpm constant power speed range and the machine's performances are analysed with finite element simulations.