ROTATION ANGLE DETECTION DEVICE

摘要

A rotation angle detection device is provided which can detect a mechanical angle of a motor having any number of pole pairs. An electrical angle detected by an AMR sensor is multiplied by ½. In the mechanical angle region of 180° to 360° where the output of the AMR sensor does not match the output of a GMR sensor, there is an offset difference of 180° between the electrical angle of the AMR sensor and the electrical angle of the GMR sensor. In this case, an offset value of 180° is added to the electrical angle of the AMR sensor. Adding the offset value in this region makes the output of the AMR sensor match the output of the GMR sensor. The AMR sensor is thus corrected. A calculated angle of the AMR sensor which is obtained by the correction is detected according to a change in mechanical angle.

主权项

1. A rotation angle detection device, comprising:
a first sensor which generates a first electrical signal according to a rotation angle of an object to be detected and whose shaft angle multiplier N is an integer, the shaft angle multiplier N representing that the electrical signal changes by N periods for one period of the rotation angle; a second sensor which generates a second electrical signal according to the rotation angle of the object to be detected and whose shaft angle multiplier n is an integer smaller than the shaft angle multiplier N of the first sensor; and an arithmetic unit that calculates the rotation angle from the first and second electrical signals, wherein the arithmetic unit calculates a first calculated angle from the first electrical signal, and calculates from the second electrical signal a second calculated angle that corresponds one-to-one to the rotation angle in a range of 0° to 360° that is a full rotation of the object to be detected, and when a difference between the first calculated angle multiplied by n/N and the second calculated angle reaches a set value that is set based on a product of n/N and 360°, the arithmetic unit calculates a correction angle by making offset correction of adding an offset value corresponding to the set value to the first calculated angle multiplied by n/N, and calculates the rotation angle based on the correction angle.