Due　to　the　lack　of　mechanical　bearing　support　for　the　dual-winding　bearingless　flux-switching　permanent　magnet　machine　(BFSPMM),　it　is　necessary　to　constantly　detect　the　radial　position　information　of　the　rotor　through　the　sensor,　which　has　some　disadvantages　such　as　high　cost　and　complex　installation　process.　In　this　article,　a　novel　rotor　radial　position　observation　method　is　proposed　to　overcome　the　above　shortcomings.　First,　the　working　principle　of　motor　rotation　and　suspension　is　analyzed,　and　the　characteristics　of　back　EMF　and　permanent　magnet　flux　linkage　with　rotor　eccentricity　in　suspension　winding　are　discussed.　Second,　according　to　the　magnetic　field　modulation　theory,　the　relation　between　the　coupled　permanent　magnet　flux　linkage　in　the　suspension　coils　and　the　eccentric　displacement　of　the　rotor　is　derived,　and　the　mathematical　model　of　rotor　radial　position　observation　is　established.　Then,　the　coupling　permanent　magnet　flux　linkage　of　suspension　winding　is　extracted　through　the　voltage　model　method,　and　the　error　of　rotor　radial　position　observation　is　indirectly　compensated.　Finally,　the　experiment　verifies　that　the　proposed　method　can　effectively　detect　the　rotor　radial　position　information.