A new approach for current sensor fault diagnosis in PMSG drives for wind energy conversion systems

Fault diagnosis is a mandatory feature in fault tolerant systems, since it provides the information necessary for the fault isolation and system reconfiguration. Recently, permanent magnet synchronous generator (PMSG) drives have achieved prominence in wind energy conversion systems (WECS), due to their reliability and availability. Therefore, in this paper a new approach is proposed for current sensor fault diagnosis in PMSG drives for WECS. As opposed to the conventional state observer-based methods for current sensor faults, which require a system model and the respective parameters, the proposed diagnostic method uses the measured phase currents only. Thus, its main merits are simplicity and reliability in the diagnosis, making it suitable for real-time implementation and to trigger remedial procedures. Additionally, current sensor and open-circuit faults can be distinguished and the affected phase is effectively identified in both cases. The proposed diagnostic technique is applied to the two power converters of a conventional back-to-back topology, and its performance is analyzed by means of several experimental results.