Fault-tolerant Back-to-back Converter For Direct-drive Pmsg Wind Turbines Using Direct Torque And Power Control Techniques

The main contribution of this paper consists of the development of an alternative direct torque control (DTC) and direct power control (DPC) schemes for both machine-side converter (MSC) and grid-side converter (GSC), respectively. Moreover, a reliable fault diagnostics algorithm without requiring additional sensors is also integrated, providing the information required to instantaneously trigger fault-tolerant remedial strategies. Fault-tolerance in wind turbines is considered crucial to increase their reliability and availability levels. This paper presents a fault-tolerant direct-drive permanent magnet synchronous generator (PMSG) using new direct control techniques, with the ability to handle power semiconductor open-circuit (O-C) faults in the full-scale back-to-back converter. The fault-tolerant topology consists of a five-leg converter, with a shared leg connected to a generator phase and to its corresponding grid phase, through a TRIAC. Simulation results are presented to validate the effectiveness of the proposed fault-tolerant PMSG drive.