Sensor and open-phase fault detection and isolation for three-phase AC drives

This paper deals with an on-line fault detection and isolation method for three-phase AC drives. The method is based on the detection of the stator current positive- and negative-sequence fundamental components expressed in the stationary αβ reference frame. These components allow calculating two fault indices used for the detection and isolation of an open-phase fault and a sensor fault, i.e. a disconnected sensor. The decision criterion is based on the CUSUM algorithm. The method includes a phase locked-loop performing the frequency adaptation needed to achieve fault detection on a wide speed range and even during speed transient. An experimental validation of the proposed method showing its effectiveness is carried out.