Based　on　the　analysis　of　compressor　load　behaviors,　a　new　three-phase　startup　strategy　for　permanent　magnet　synchronous　motor　(PMSM)　compressor　is　presented,　which　includes　parking,　open-loop　startup　and　closed-loop　operation.　When　the　speed　loop　closes,　an　improved　method　of　flux　estimation　for　PMSM　compressor　sensorless　control　is　proposed,　which　accomplishes　parking,　efficient　speed　estimation　and　disturbance　eliminating,　it　is　caused　by　integrating　element　of　back　electromotive　force　(BEMF).　A　laboratory　prototype　has　been　fabricated　using　this　strategy　and　system　analysis,　measured　experimental　results　are　presented.　©　2010　Crown　Copyright.