Patent ID: 8942952
Filing Date: 2015-01-27
Classification: G01D

Abstract:
1. A rotation angle detection apparatus, comprising: a magnet that rotates as a rotor rotates, and that has multiple magnetic poles arranged in a circumferential direction of the magnet; a first magnetic sensor that outputs, as the magnet rotates, a sinusoidal signal on which a third harmonic component is superimposed; a second magnetic sensor that outputs, as the magnet rotates, a sinusoidal signal on which a third harmonic component is superimposed and of which a phase is different from a phase of the sinusoidal signal output from the first magnetic sensor; a third harmonic component removing unit that corrects the sinusoidal signals output from the first magnetic sensor and the second magnetic sensor so as to remove the third harmonic components from the sinusoidal signals; and a rotation angle calculating unit that calculates a rotation angle of the rotor based on the sinusoidal signals corrected by the third harmonic component removing unit, wherein the third harmonic component removing unit comprises: a unit that calculates a post-correction signal V a unit that calculates a post-correction signal V wherein K is a third harmonic component gain that is larger than zero but smaller than 1 (0<K<1), V