A new three-phase dual-rotor middle-stator brushless flux switching generator (FSG) for 400 Hz diesel-driven aircraft ground power units. For the proposed machine, both field and armature windings are hosted in the stator in such a way that not only fulfils brushless structure, but also realizes the flux switching function. Moreover, both windings have non-overlapping concentrated windings to shorten the end-windings and reduce the copper losses. In the meantime, the rotor has only slots without any active parts.