Electric power steering apparatus, and method for detecting abnormality of angle detector thereof

摘要

An electric power steering apparatus which comprises: an angle detector 25 for outputting a sine wave signal and a cosine wave signal corresponding to a rotor position of a brushless DC motor 6; and a torque detector 3 for detecting a steering torque applied to a steering member 1, and which drives the brushless DC motor 6 to assist steering based upon the sine wave signal and the cosine wave signal which were outputted from the angle detector 25 and the steering torque detected by the torque detector 3. A sine wave signal and a cosine wave signal are squared and added to each other, and whether or not abnormality has occurred in the angle detector 25 is detected by whether the addition result falls within a predetermined range. It is possible to detect abnormality in the angle detector at an early stage.