High Precision On-line Offset Correction for Motor Angle Sensors

Abstract

In this paper, an angle detecting system is proposed that calculates the offset correction values for the sine and cosine signals of angle sensors. The offset correction values are calculated not from the offset errors of the sine and cosine signals but from the 1f angle error (the fundamental frequency component of the sine and cosine signals) of the angle signals. Therefore, the system can correct the 1f angle error even when the sine and cosine signals contain the double-frequency components of the sine and cosine signals, as well as the DC offset errors. Moreover, it is possible to use low-cost microcomputers with low computing speed, because the offset correction values are DC quantities.