Michael Wolff

Michael Wolff M.Sc.


Fraunhoferstr. 4
64283 Darmstadt

Office: S3|21 205

More information

Research topic

Today, failures of power semiconductor and its package are one of the sources of drive system break down. With the increase of renewable energy sources the importance of power semiconductors increase further and therefore the demand for reliability or predictive maintenance.

Especially in applications with a high expectations towards reliability, such as offshore wind power, knowledge about the state of a system helps to optimize maintenance effort and therefore potentially decreases its cost. Furthermore, the monitoring of the degradation process gives insight of the semiconductors ageing behavior depending on its operation condition. This potentially provides information to improve the operation conditions for a longer semiconductor lifetime.

So far many approaches to get information about the state of health of a power semiconductor focus on thermal sensitive electrical parameters (TSEPs). These parameters change with increasing chip temperature, caused by ageing of the semiconductor or its packaging.

The Approach of this Project

The approach of this project does not focus on the thermal drift due to ageing but on a proposed change in the spatial magnetic field distribution around the chip due to changes in the current distribution of the chip and the packaging. The placement of magnetic field sensors at dedicated locations close to the semiconductor allows the measurement of these changes. In theory, this will enable a new approach for the on-line monitoring of power semiconductors without interrupting its regular operation for data acquisition.

The project is a proof of concept for the proposed method considering the state of the art. Thereby especially the ageing of the solder connection and IGBTs are in the focus.

Main targets of the Project:

- Development of an IGBT FEM-model to estimate the changes in the magnetic flux distribution due to ageing of the chip-solder connection.

- Development of a prototype measurement setup to determine the changes of the magnetic flux distribution

- Development of a rule for systematic correlation for the change of the spacial magnetic field distribution and the ageing of semiconductors

go to list