Patent ID: 6020737
Filing Date: 2000-02-01
Classification: G01B,G01D,H02K

Abstract:
A resolver for measuring and detection of angular positions and revolutions of a shaft, using an induced magnetic field between a stator having stator windings and a rotor for determining position of said shaft and together forming part of the resolver, said stator windings comprising an induction coil and at least one measurement coil, the rotor being provided with circumferential permanent magnetic North pole and South pole surfaces which interact with the stator windings to induce voltage, the pole surfaces being designed in such a manner that a magnetic flux develops induced voltages for identifying each angular position of the rotor, wherein a soft magnetic material configuration disposed between the North pole and South pole surfaces for defining a specific magnetic flux distribution pattern is positioned on the rotor, and said soft magnetic material consists of one of the following materials: RSi 24, RNi 8 or RNi 5, a compensation coil provided to compensate a stray magnetic field resulting from the induction coil and/or from the measurement coil which would reduce the accuracy of determining the resolver shaft position, said compensation coil being located at the measurement coil to maximally couple magnetic flux, and means to determine and adjust current through the compensation coil.