Rotor eddy loss in high-speed permanent magnet synchronous generators

Analytical and transient finite element analysis (FEA) methods are used to calculate on-load rotor eddy current power loss in permanent magnet machines taking into account the effect of the reaction of eddy currents. The effect of the phase advance angle between the back electromotive force, and the phase current on rotor eddy current power loss is investigated. Both magnet flux tooth ripple and magnetomotive force harmonics are considered in the analytical calculation of rotor loss; the harmonics of the magnet tooth ripple flux and armature reaction flux are added vectorially. Good agreement between analytical and FEA results is observed when the stator laminations are assumed to have a linear BH curve. However, a significant discrepancy is observed between the analytical and FEA solutions when a non-linear BH curve is used.