To enable the development of more electric aircraft, drivetrain inverters must achieve extreme power density and efficiency while maintaining a low distortion output current. The flying capacitor multilevel converter (FCML), has demonstrated impressive performance in these applications. In this work, an optimal combination of capacitors is utilized for each flying capacitance, which allows for greater than 50 % reduction in size compared to the conventional approach. A novel layout of the converter is introduced, which enables the use of these uniquely sized flying capacitors within a minimal box volume. Based on this approach, an 800 V, 10.4 kW, 14-level FCML prototype is constructed, which achieves 175 kW/kg gravimetric power density, 6.2 kW/in^3 (380 kW/L) volumetric power density and 98.3 % peak overall efficiency.
