Patent ID: 8853983
Filing Date: 2014-10-07
Classification: G01D

Abstract:
1. A fractional absolute rotary position encoder, the fractional absolute rotary position encoder being arranged to be directly or indirectly mounted to a rotor of an N-pole electrical motor, where N is equal to or greater than four, the encoder comprising: a sensing device, arranged to at least partly be mounted one of directly and indirectly to the rotor and to provide a measure corresponding to a rotation of the rotor wherein the measure is in the form of a continuous signal representing an absolute position of the rotor within a pole through which the rotor is moving; a processing device, arranged to provide an absolute rotary position value from the continuous signal received by the sensing device such that the processing device can determine the position of the rotor continuously and at any location within the pole through which the rotor is moving; and wherein the absolute rotary position value repeats N times for a full turn of the rotor thus providing an absolute rotary position encoding with unique values only over an angle that corresponds to an angle between two consecutive poles of the electrical motor.