Aiming　at　the　problem　of　speed　fluctuation　of　permanent　magnet　synchronous　motor　(PMSM)　caused　by　periodic　load　change　during　the　operation　of　scroll　air　compressor,　a　sensorless　control　method　based　on　linear　active　disturbance　rejection　control　(LADRC)　and　high-order　sliding　mode　observer　(HSMO)　is　proposed.　The　HSMO　is　utilized　to　observe　the　rotor　position　information.　To　mitigate　the　impact　of　load　disturbances　on　the　observation　effectiveness　of　the　HSMO,　the　LADRC　for　speed　loop　is　designed.　The　simulation　results　demonstrated　that　the　HSMO　can　accurately　observe　the　rotor　position　information　under　the　load　fluctuations.　Additionally,　compared　with　the　PI　controller,　the　range　of　speed　fluctuations　was　reduced　by　1.06%　through　LADRC,　thereby　significantly　enhancing　the　stability　of　scroll　air　compressor　operation.　　©　2024　IEEE.