Hybrid excited flux-switching permanent magnet machines

Hybrid excited machines are of interest due to the potential of combining the high power density of PM machines with the flux-adjusting capability of wound field excitation. This paper reviews currently documented hybrid excited machines and compares the flux control performance and torque density of alternative hybrid flux-switching PM machines by means of finite element analysis. The iron loss of the most promising design is calculated and shown to be much reduced from a conventional FSPM machine and it is shown that at high speed the iron losses can be reduced further by applying negative current to the field coil.