NanoLam Technology for efficient DC Link Capacitors

Authors

M. Breuer, T. Schorn, S. Schmitt, K. Grimm - Rheinmetall AG

Summary

DC Link Capacitors are a crucial component of modern inverters for AC motors. Increasingly, emphasis is being directed to optimizations in energy density, higher operating temperatures, and low parasitic inductance, while exhibiting good self-healing properties. Moreover, flexibility in design, and a competitive cost structure are required.

NanoLam™ Technology is a novel approach for an in-situ process that leverages the use of sub-micron thermoset dielectric systems allowing for ultra-compact form factors while exhibiting excellent electrical and heat transfer properties when compared to conventional DC link capacitor technologies. This paper explains the production process and the gained design opportunities.

The relations for capacitance as a function of occupied volume, heat dissipation due to the internal ohmic losses, as well as energy release by heat conductivity are derived. It is further demonstrated why and how some of the trade offs can be addressed by the tailored NanoLam™ approach.

Finally, key performance figures are compared to state- of - the-art capacitors and design recommendations are shared to take full advantage of the NanoLam™ technology.

Rheinmetall PolyCharge GmbH - a joint venture between Rheinmetall AG and PolyCharge America established 2021 - will serve the European market with bespoke DC link capacitors.