A permanent-magnet switched-flux (PMSF) apparatus comprises a plurality of permanent-magnet switched-flux (PMSF) devices, wherein each of the plurality of PMSF devices comprises a ferromagnetic outer rotor coupled to a shaft, wherein the ferromagnetic outer rotor comprises a plurality of permanent-magnets coupled to an inner surface of the ferromagnetic outer rotor, an inner stator rotatably disposed in the ferromagnetic outer rotor, wherein the inner stator comprises a stator core and multiple serrated edges forming multiple stator poles distal from the stator core, wherein the multiple stator poles are configured to interface with the plurality of permanent-magnets, and a coil disposed on the stator core between the multiple stator poles, wherein the coil is coupled to the plurality of permanent-magnets, wherein a magnetic flux of the plurality of permanent-magnets is operable to pass through the coil, and wherein the magnetic flux is configured to switch to an opposite direction in response to a rotation of the ferromagnetic outer rotor.