energies Article Exploring the Causes of Power-Converter Failure in Wind Turbines based on Comprehensive Field-Data and Damage Analysis Katharina Fischer 1,* , Karoline Pelka 1, Sebastian Puls 2, Max-Hermann Poech 2, Axel Mertens 3, Arne Bartschat 1, Bernd Tegtmeier 1, Christian Broer 1 and Jan Wenske 1 1 Fraunhofer Institute for Wind Energy Systems (Fraunhofer IWES), 30159 Hannover, Germany;
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[email protected] (M.-H.P.) 3 Institute for Drive Systems and Power Electronics IAL, Leibniz University Hannover, 30167 Hannover, Germany;
[email protected] * Correspondence: katharina.fi
[email protected]; Tel.: +49-471-14290-542 Received: 30 December 2018; Accepted: 11 February 2019; Published: 13 February 2019 Abstract: Power converters are among the most frequently failing components of wind turbines. Despite their massive economic impact, the actual causes and mechanisms underlying these failures have remained in the dark for many years. In view of this situation, a large consortium of three research institutes and 16 companies, including wind-turbine and component manufacturers, operators and maintenance-service providers has joined forces to identify the main causes and driving factors of the power-converter failures in wind turbines to create a basis for effective remedial measures. The present paper summarizes and discusses the results of this research initiative, which have been achieved through the evaluation of converter-specific failure and operating data of a large and diverse worldwide wind-turbine fleet, field measurements as well as post-mortem investigation of returned converter components.