Maximilian Bleicher, M. Sc.

Research Staff Profile

• Research Topic - Measurement and Mitigation of High-Frequency Effects
  What is your research topic and what is it about?

  My research focuses on high-frequency effects in electric drives, in particular bearing currents and ways of reducing them. These effects occur mainly in inverter-fed drive systems, which are now widely used in energy technology, electric mobility, and industrial applications. One focus of my work is the high-frequency-compliant measurement of real drive systems in the laboratory. The aim is to capture electrical stresses as realistically as possible without unintentionally distorting the system through the measurement setup itself.

  Another focus of my research is shaft-grounding systems. These provide a low-impedance connection between the motor shaft and the stator housing (ground), thereby reducing the voltage across the bearing. Although they are among the most widely used mitigation measures, their high-frequency behaviour is still not sufficiently understood. To be effective in practice, they therefore need to be properly understood and applied under the right conditions. I investigate how these systems behave under high-frequency conditions, when they work well, and where their limitations lie.

  Why is your topic relevant?

  For a long time, electric machines were operated directly from the grid. Under those conditions, the parasitic high-frequency effects that are relevant today played virtually no role. Only with the widespread adoption of inverter-fed operation and fast-switching semiconductors in the 2010s have these effects come into focus. They can damage machine components such as bearings and, in the worst case, reduce the reliability and service life of the overall system.

  At the same time, these effects are difficult to capture experimentally. Conventional measurement methods often do not reflect the actual behaviour of the system, but rather a distorted picture caused by the measurement setup itself. Assessing high-frequency effects reliably and applying mitigation measures effectively therefore requires high-frequency-appropriate measurement methods, a deep understanding of the system, and realistic investigations.

  This also makes the topic highly relevant for industry: when unexpected high-frequency effects occur in real applications, they are often difficult to address without a sound understanding of the underlying system behaviour. Precisely because the field is still relatively young and many aspects remain insufficiently explored, it offers exciting research questions with direct practical relevance.