Advanced derating strategy for extended lifetime of power electronics in wind power applications

It is well known that one of the main causes of failure in wind power applications is due to the power converter and its semiconductor devices. Consequently, the main objective of this paper consists of analyzing the impact of converter derating on the lifetime of the power devices by means of advanced reliability models and tools. The wind power system together with the thermal cycling in the power semiconductor devices has been modeled and the dynamic behavior of the system has been analyzed under certain mission profiles. Based on the thermal loading of the devices, the lifetime estimation is carried out, and by computing the total accumulated damage, the optimal point in which the converter derating should occur can be determined. Finally, by using the reliability tools, the converter derating strategy is modeled and analyzed and the obtained results are compared with the normal operation case, by means of quantified lifetime estimation.