Optimal Split Capacitor DC-Link Design for Partial Load Multi-Level Inverters

A novel DC-link capacitor design methodology tailored for multi-level inverters with partial load optimization capabilities is introduced. By employing a split DC-link capacitor configuration, this approach minimizes the overall capacitance requirement while ensuring high system efficiency. Applied to a $2 \mathrm{~L} / 3 \mathrm{~L}$-capable TNPC inverter, the method achieves a $71 \%$ reduction in total capacitance and a $34 \%$ decrease in stored capacitor energy. These improvements pave the way for enhanced energy efficiency, increased power density, and lower costs in multilevel traction inverter designs for future battery electric vehicles and other high-power converter applications.