Multi-Level Converters

A Key Technology for Efficient and Cost-Effective Power Electronic Systems

© Fraunhofer IISB
Basic Switching cell (3,3 kV / 1500 A) of a modular multi-level converter.

The disadvantages of high-blocking voltage semiconductors can be overcome using multi-level converters. The latter are key in efficient and cost-effective power electronic systems in high- and medium-voltage applications. They also provide better EMC performance for smaller size and less cost. Specially adapted joining technologies are used to increase the lifetime of these multilevel systems.

New application-specific power module concepts allow the integration of protection mechanisms to improve the converter behavior and availability in case of system or device failure. One drawback of such multi-level topology concepts is the increased number of semiconductor switches that have to be controlled. Especially in small- and medium-power systems, the effort required to control the simultaneous switching is a significant factor in total system cost. These technology developments are just individual examples of the Fraunhofer IISB development of optimized control and communication systems as key elements in cost-efficient multi-level systems.


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