Angular position sensor and associated method of use

An angular position sensor comprising:

• two planar excitation coils forming a substantially circular interior area;
• two planar sensing coils positioned within a minor sector of the substantially circular interior area, the minor sector having a central angle of about 120° and each of the two planar sensing coils comprising a clockwise winding portion and a counter-clockwise winding portion, wherein each of the clockwise winding portion and the counter-clockwise winding portion are positioned within one of four equal subsectors of the minor sector of the substantially circular interior area and wherein each of the four equal subsectors of the minor sector has a central angle of about 30°;
• and
• a substantially circular non-ferromagnetic coupling element positioned in overlying relation to the two planar sensing coils and separated from the two planar sensing coils by an airgap, wherein the substantially circular rotatable inductive coupling element comprises three sector apertures that are substantially evenly spaced on the circular rotatable inductive coupling element, each sector aperture having a central angle of about 30°.

A method for sensing an angular position of a rotatable inductive coupling element, the method comprising:

• establishing a magnetic coupling between two planar excitation coils and two planar sensing coils to induce a time varying voltage in the two planar sensing coils, wherein the two planar sensing coils are positioned within a minor sector of a substantially circular interior area formed by the two planar excitation coils and wherein each of the two planar sensing coils comprises a clockwise winding portion positioned opposite a counter-clockwise winding portion;
• positioning a rotatable inductive coupling element comprising three sector apertures that are substantially evenly spaced on the circular rotatable inductive coupling element in overlying relation to the two planar excitation coils and separated from the two planar excitation coils by an airgap, the position of the sector apertures of the rotatable inductive coupling element to cause a variation in a magnetic coupling between the two planar excitation coils and the winding portions of each of the two planar sensing coils responsive to rotation of the positioned rotatable inductive coupling element;
• and
• measuring a time varying voltage induced in the two planar sensing coils as a result of the variation in the magnetic coupling to determine an angular position of the rotatable inductive coupling element relative to the position of the two planar sensing coils.