Open-circuit faults diagnosis in back-to-back converters of DF wind turbine

The open-circuit fault in converters is one of the wind turbine faults, which degrades the power quality and can even cause potential secondary faults in other components. So, an effective fault diagnostic technique for wind turbine converters is needed. This study presents a new open-circuit fault diagnostic approach for back-to-back converters of doubly fed (DF) wind turbines. The proposed fault diagnostic method has fault detection and fault localisation. The fault detection is based on the absolute normalised Park's vector approach; this method can detect multiple open-circuit switch faults and guarantee immunity to false alarms when the DF induction generator operates around the synchronous speed. For fault localisation, this approach applies the normalised current average values, which can be used to identify single and double open-circuit switch faults. The simulation and experimental results indicate that the diagnostic method can not only diagnose multiple open-circuit faults, but that false alarms due to transients can be avoided.