Brushless rotary position transducer

摘要

A brushless resolver has first and second ring-shaped magnetic pole elements spaced from each other along a common axis. An excitation coil is wound axially between the two pole elements. First and second output coils are wound through the first and second pole elements and spaced radially from each other. A rotor is within the pole elements and has a shaft extending along the axis. First and second magnetic coupling elements are spaced along the shaft each of which being coplanar with a different one of the pole elements. Each coupling element providing 180 degrees of magnetic coupling with respect to the corresponding pole element. A high frequency signal applied to the excitations coil is transformer coupled to the output signals. The degree of coupling varies with the position of the coupling elements. The demodulated signal from each of the output coils has a triangular shaped waveform which may be directly differentiated to produce the angular velocity of the rotor shaft.