Patent ID: 7723942
Filing Date: 2010-05-25
Classification: H02K,H02P

Abstract:
1. An integrated motor and position sensor comprising: a motor comprising a rotor assembly including a cylindrical portion having an axis, the cylindrical portion having a plurality of peripherally-spaced and alternately magnetized regions, a stator assembly coaxial with the rotor assembly and having a plurality of projecting stator poles projecting toward the rotor assembly, arranged substantially coaxial with the rotor assembly, and energizing coils for electrically energizing the stator poles to produce driving magnetic flux to alter a relative position between the rotor assembly and the stator assembly; and a plurality of sensing coils placed to intercept magnetic flux between a plurality of the stator poles and the rotor assembly, wherein at least one magnetic stator pole is distributed among multiple adjacent physical stator pole pieces with the energizing coils producing magnetic flux that is in phase through each of the associated physical stator pole pieces, at least one set of the sensing coils is positioned to differentially sense at least a portion of the magnetic flux from a plurality of the stator pole pieces associated with at least one magnetic stator pole, and the sensing coils responsive to variations in both the driving magnetic flux and to the relative position of the rotor assembly with respect to the stator assembly.