Torque ripple reduction based on current control for a flux switching permanent magnet machine

It is often noted in the literature that flux switching permanent magnet machines (FSPMs) exhibit “torque ripple”. We derive a detailed torque model of a 50 kW proof-of-concept FSPM and use this model to calculate reference trajectories for the current which lead to a ripple-free torque. Since these current trajectories contain higher frequencies we were concerned that structure-borne vibrations might be affected unfavourably as a side-effect. However, the concern turned out to be unjustified; instead of an increase, a minor decrease of vibrations was measured on the 50 kW FSPM.