IGBTs and current sensors fault diagnosis in direct-drive PSMG wind turbine systems using adaptive thresholds

Condition monitoring and fault diagnosis are considered key features in order to increase the reliability and availability levels of wind turbine systems. Accordingly, this paper proposes a single fault diagnostic algorithm for multiple IGBTs open-circuit faults and current sensor faults in direct-driven wind turbines, based on permanent magnet synchronous generators with full-scale back-to-back converters. The proposed method is based on the currents residual generation and on a new adaptive threshold approach. This threshold is calculated from the measured currents and their corresponding reference signals that are already available from the main control system. The proposed diagnostic technique is applied to both generator-side and grid-side converters of a conventional back-to-back topology. Several simulations are presented, showing the algorithm reliability against false alarms under both multiple IGBTs and current sensor faults in the back-to-back converter.