Rotor-current and position estimator for doubly-fed induction generators - application to sensor-fault detection

A combined encoder and rotor-current-sensor fault detection and isolation algorithm for doubly-fed induction machines is presented. A rotor-position and current estimator based on air-gap power vector computation is used for residual generation. A cumulative-sum function permits detecting and isolating the investigated faults. The algorithm is experimentally tested on a 3 kW generator in steady and transient regimes. Sensor outages as well as current-sensor gain drifts and offsets are investigated. Transients do not significantly affect the algorithm, which also allows for a very short detection time for the most critical faults.