An effective encoder fault detection in PMSM drives at different speed ranges

Incremental encoder is widely used as a rotor speed and/or position sensor for electric machines control. It gives the exact rotor speed and/or position for electric motors closed-loop operating. However, a faulty sensor may lead to the loss of motor control. In this paper, an improved detection of encoder information loss fault in Permanent Magnet Synchronous Motor (PMSM) drives is presented. The information loss fault detection has been performed at different speed ranges, from very low-speeds to high-speeds. For this purpose, two detection approaches have been used. The first approach is based on Luenberger observer, and the second approach is the Discrete Wavelet Transform - based MultiResolution Analysis (DWT-MRA). Basing on the obtained results, discussion and analysis are given in order to highlight the effectiveness of the proposed methods for incremental encoder faults detection in PMSM drives.