Reliable power converters for renewables – power4re

Funding: Fraunhofer-Gesellschaft in the scope of the internal program PREPARE
Partners: Fraunhofer Institute for Integrated Systems and Device Technology IISB, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Fraunhofer Institute for Solar Energy Systems ISE, Fraunhofer Institute for Wind Energy Systems IWES (project lead), Fraunhofer Institute for Reliability and Microintegration IZM, ConverterTec (formerly Woodward Kempen), SMA Solar Technology AG, Mitsubishi Electric R&D Centre Europe
Duration: 03/2020 – 11/2023


  • Frequency converters and inverters are required to feed the electricity from wind turbines and photovoltaic systems into the power grid.
  • They are subject to challenging operating and environmental conditions and are among the system components which fail most frequently. This often results in high costs.
  • The power4re project is therefore aimed at developing new measures to increase the reliability and robustness of these essential components.
  • power4re is financed with funds amounting to €3.5 million in total in the scope of the Fraunhofer-Gesellschaft’s internal research program PREPARE.

Converters play a central role in the energy transition: they are vital power electronics components for connecting photovoltaic systems and modern wind turbines to the power grid in order to feed in energy from renewable sources at a grid-compliant voltage and frequency. The converters thus have to be extremely reliable. Yet, they are subject to particularly challenging operating and environmental conditions. For years they have been among the system components most likely to fail, often causing substantial repair costs and triggering considerable downtimes. As such, there is a great demand for long-lasting converters which are able to withstand environmental influences. They also offer high economic potential as an indispensable technological component of the energy transition.

The goal of the three-year power4re project is therefore to develop solutions for substantially improving the reliability and robustness of converters for decentralized electrical energy conversion. This project focuses on investigating in greater detail the application-specific weaknesses determined on the basis of comprehensive field data and damage analyses and their failure mechanisms. Such mechanisms are often the result of the combination of climatic and electrical loads. In addition to hardware modifications and protection concepts, the project is also exploring suitable testing procedures in order to assess them under typical application conditions as well as methods for early fault detection.

power4re is funded as part of the Fraunhofer-Gesellschaft’s internal research program PREPARE. One important aspect here is the expansion of long-term alliances between Fraunhofer institutes. In total, five Fraunhofer institutes are participating in the power4re project with Fraunhofer IWES taking the lead. The project receives support from a team of consultants, including representatives of three companies from project-relevant sectors.

Fraunhofer IWES’ focuses in the power4re project are on the opening up of machine learning methods for field-data based failure analysis, detailed measurement of the temperature and humidity conditions within wind turbine converters in the field, and the development of a condition monitoring system which is focused on the relevant failure mechanisms. The collaboration between the institutes is viewed as particularly valuable as for example the comparison of converters in wind energy and photovoltaic applications offers new opportunities for insights.