Failure behaviour of power converters in wind turbines

Frequent failures of power converters in wind turbines lead to turbine downtimes and cause considerable maintenance cost. In order to increase the power-converter reliability, the understanding of failure causes and mechanisms has to be enhanced. This paper presents results of a statistical analysis of comprehensive field-failure data based on a dataset covering more than 2900 wind turbines. The analysis aims at comparing the converter reliability of turbines with different generator-converter concepts and at determining the temporal failure behaviour of the converter core component phase module. The converter reliability in turbines with electrically-excited synchronous generator is found to be higher than in turbines with doubly-fed induction generator or squirrel-cage induction genera tor. The results indicate an early-failure behaviour of the phase-module component.