Impedance Distortions Based Interturn Fault Diagnosis in PMSM Drive

Interturn fault (ITF) is a commonly occurring fault in permanent magnet synchronous machine (PMSM). The propagation of the ITF could cause damage to the entire electrical machine if it is not detected in time. In this proposed technique, second order harmonic components in dq-reference frame impedance distortions are used for ITF detection in field-oriented controlled PMSM drive. The dq-reference frame impedance distortions are obtained from the voltage distortions and current distortions by using the Luenberger observer, and also by healthy and faulty analytical models of PMSM. These dq-reference frame impedance distortions are transformed to negative-sequence reference frame. Then the magnitude of dc components obtained from negative-sequence dq-reference frame impedance distortions is defined as fault index. Further, the comparison with the dq-reference frame current residuals ITF detection technique shows the superiority of the proposed technique.