Single-winding　bearingless　flux　switching　permanent　magnet　motor　(BFSPMM),　characterized　by　its　frictionless　operation,　maintenance-free　nature,　and　high　efficiency,　holds　the　potential　to　fundamentally　address　the　issues　of　bearing　erosion　and　failure　in　marine　propulsion　motors　caused　by　harsh　oceanic　environments.　However,　the　torque　and　suspension　forces　are　strongly　coupled,　and　the　radial　forces　are　complex　and　variable,　resulting　in　significant　rotor　displacement　ripples　that　severely　impact　the　performance　of　electric　drive　systems.　Herein,　a　suspension　internal　model　control　strategy　with　active　ripple　suppression　is　proposed.　Firstly,　based　on　the　magnetic　field　modulation　theory,　the　mechanism　of　unbalanced　magnetic　pull　is　analyzed　in　detail,　and　the　corresponding　expressions　are　established.　Then,　a　rotor　dynamic　model　is　derived　from　the　differential　equations　of　a　whirl　for　the　suspended　rotor,　which　facilitates　the　construction　of　the　BFSPMM　internal　model.　A　linear　extended　state　observer　is　employed　to　obtain　smoother　displacement　error　signals,　differential　signals,　and　account　for　unmodeled　dynamics.　Subsequently,　an　inverse　system　model　for　the　controllable　suspension　force　is　derived,　and　the　internal　model　controller　is　formulated　and　analyzed　in　an　innovative　PD-based　structure.　This　approach　not　only　enhances　the　controller＇s　performance　but　also　simplifies　the　tuning　process,　requiring　only　two　parameters　to　be　adjusted.　Finally,　the　performance　of　the　proposed　method　is　analyzed　theoretically,　and　its　effectiveness　is　validated　through　experimental　verification.　©　1986-2012　IEEE.