Understanding wind turbine power converter reliability under realistic wind conditions

The reliability of wind turbine power converters is crucial for analyzing wind energy project costs, and for estimating maintenance and downtime. The published literature in this field relies on evaluating the reliability effect of wind speed to estimate the converter lifetime. However, this paper demonstrates that wind turbulence intensity, which has not been widely considered in similar reliability analyses, shows a significant impact on converter lifetime. This paper uses 821 10-min wind speed time series sampled at 1 Hz on the two most commonly deployed wind turbine converter topologies: the two-level voltage source and the three-level neutral point clamped. Electromechanical and thermal modelling, combined with statistical analysis shows that mean wind speed and turbulence intensity both impact the lifetime of both converter topologies. However, the paper estimates that the three-level converter can operate 2.4 to 4.0 times longer than the two-level converter depending on the operating wind speed and turbulence intensity.