Reliability comparison of fault-tolerant 3L-NPC based converter topologies for application in wind turbine systems

Fault-tolerant operation could be an efficient way to increase the reliability of the power electronic converter. Although different fault-tolerant topologies have been proposed in the past, there are only few investigations clarifying the benefit for particular applications. This paper aims to answer this question in regard to wind turbine system application using three-level neutral-point-clamped back-to-back converters. Therefore related fault-tolerant converter topologies are studied, compared and evaluated with focus on reliability and cost issues.