Commutation Angle Self-Calibrating Technique for Brushless DC Motor Drives with Defective Hall-effect Position Sensors

In this study, a current monitoring approach is proposed for Hall-effect position sensor-based Brushless DC motor drives to detect and mitigate the inherited defect of the misaligned position sensors. Considering a single sensor approach, DC-link current monitoring and frequency-domain analysis are exploited for the unbalanced system operation diagnosis and commutation signal reconstruction with a minimum error. Thus, both relative and absolute misalignment errors are investigated. The second harmonic component of the DC-link current frequency spectrum is evaluated as a potential fault signature of the unbalanced system operation due to single, double, and triple defective configurations of the position sensors. In addition, the Goertzel algorithm is exploited for the implementation of the harmonic analysis in a narrow frequency band, while a filtering stage, based on wavelet decomposition, is proposed for the initial characterization of reference sensor. Finally, DC-link current third harmonic component is proposed for the absolute error estimation.