Hall-effect sensor fault identification in brushless DC motor drives using wavelets

In this study, a diagnostic method to identify potential faults of Hall-effect sensors in brushless DC (BLDC) motor drives is proposed. The wavelet signal theory is evaluated as an alternative diagnostic method, able to identify either a breakdown or a misplacement of a position sensor. The proposed method combines the required noise insensitivity with the measurement of a single signal. Since the DC-link current of the inverter input is highly affected by erroneous position sensing and usually measured in BLDC drives, it was chosen as the only necessary informational signal. Consequently, the wavelet signal theory was assessed as the first stage of a fault tolerant control system (FTCS) and its effectiveness to identify both types of position sensor faults was experimentally verified.