A　sensorless　control　method　based　on　novel　extended　electromotive　force　models　considering　parameter　variation　is　proposed　for　the　interior　permanent　magnet　synchronous　motor(IPMSM).　Based　on　the　variation　of　inductance　parameters,　the　function　relation　between　inductance　parameters　and　stator　current　is　introduced　into　the　dynamic　equation　of　motor,　and　the　motor　model　considering　parameter　variation　is　derived.　The　extended　EMF　in　the　rotating　reference　frame　is　estimated　by　a　least-order　observer,　and　the　estimation　position　error　is　obtained　from　the　extended　EMF.　The　proposed　system　is　very　simple　and　easy　to　design.　The　simulation　results　of　the　traditional　control　algorithm　and　the　proposed　control　algorithm　are　compared.　Verify　the　feasibility,　reliability　and　convergence　of　the　proposed　control　strategy.　©　2020　IEEE.