Component-level Reliability Assessment of a Direct-drive PMSG Wind Power Converter Considering Long-term and short-term thermal cycles

The lifespan of a wind power system is highly influenced by the reliable operation of its power converter. This paper investigates the failure rate and annual consumed damage for a 2 MW direct-drive permanent magnet synchronous generator (PMSG) based power converter in a wind power generation system. The reliability assessment mainly focuses on the component level, namely, diodes and IGBTs, in the machine-side converter (MSC). Annual damages and power cycles for semiconductors are calculated separately under long-term thermal cycles (several minutes to several hours) and short-term thermal cycles (dozens to hundreds of milli-second). A comparison result between different thermal cycles are given and discussed in detail. To ensure an effective lifetime evaluation of the entire converter system, a Monte Carlo method is used to generate the lifetime distributions and entire unreliability functions for power semiconductors. Final B 10 and B 1 lifetimes can be easily observed from the cumulative distribution functions (CDFs).