Reduced-inductance modular multilevel converter for high voltage direct current systems: A control-driven approach to lower magnetic material utilization and increase power density

Principal investigator: Brandon Grainger

Co-PI: YuAnn Li

University: University of Pittsburgh

Industry partner: Innomotics, LLC

This project advances modular multilevel converter technology for high-voltage direct current and high-powered drive applications by replacing bulky arm inductors with a control-oriented design that significantly reduces magnetic material. Current MMC systems depend on large inductors to suppress circulating current, leading to excessive copper usage, heavy system mass, increased cost, and substantial installation footprint. We propose a reduced-inductance MMC architecture where circulating-current stabilization is achieved through modulation-based control rather than hardware scaling. This approach reduces inductance volume, lowers parasitic resistance, and improves overall efficiency.

The work will design, simulate, and experimentally validate a Phase-A MMC with substantially reduced inductance using real-time control hardware, a 400-volt/30-ampere supply, sensing instrumentation, and benchmark grid inductors for comparison. Expected results include smaller inductors, reduced material demand, and higher efficiency operation. The outcome directly benefits Pennsylvania HVDC and drive manufacturers, including ABB, General Electric, Eaton, HICO, Innomotics, and Mitsubishi Electric.