Optimal Derating Strategy of Power Electronics Converter for Maximum Wind Energy Production with Lifetime Information of Power Devices

One of the most important causes of failure in wind power systems is due to the failures of the power converter and due to one of its most critical components, the power semiconductor devices. This paper proposes a novel derating strategy for the wind turbine system based on the reliability performance of the converter and the total energy production throughout its entire lifetime. An advanced reliability design tool is first established and demonstrated, in which the wind power system together with the thermal cycling of the power semiconductor devices are modeled and characterized under a typical wind turbine system mission profile. Based on the reliability design tools, the expected lifetime of the converter for a given mission profile can be quantified under different output power levels, and an optimization algorithm can be applied to extract the starting point and the amount of converter power derating which is necessary in order to obtain the target lifetime requirement with a maximum energy production capability. A nonlinear optimization algorithm has been implemented and various case studies of lifetime requirements have been analyzed. Finally, an optimized derating strategy for the wind turbine system has been designed and its impact has been highlighted.