Multi-Level Converter Multiplier Effect in Propulsion System Performance

This project on multi-level converters is a collaboration between LaunchPoint EPS Inc. and Prof. Pilawa-Podgurskirsquo;s lab at UC Berkeley. Multi-level converters enable increased power density of the converter itself, and, by producing higher quality power signals, they enable dramatic improvements in EMI filter power density and also improvements in motor power density. In a compelling example of a DC-to-AC converter from Prof. Kolarrsquo;s group at ETH, moving from 2 to 3 levels reduced EMI filter weight by an astounding 89% of the converter weight. We call this system-level effect the Multi-Level Multiplier (MLM) effect and define the MLM quantitatively in the project as a measure of propulsion system improvements made possible with a multi-level converter. The innovations in this project are 1) use of the MLM to think about, choose, and optimize converters as components of propulsion systems, and 2) augment our MAAPreg; software design tool such that full propulsion systems incorporating flying capacitor multi-level (FCML) converters can be optimized. The resulting power-density advances are critical and significant to our existing customer projects and future megawatt-level projects.Our technical objective in Phase I is to demonstrate, by analysis, that FCLM converters indeed yield transformative MLMs. The objective will be attained by designing two propulsion systems comprised of combined EMI filter/converter/motor systems. One design will be based on an updated version of our standard 2-level converter models, and the other design will be based on 3-copies of our 10-level FCML converter rated at 13.46 kW, 26.7 kW/kg, 98.6% efficient to form a 3-phase motor drive.