Reduction of Passive Components in Quasi-2-Level Operated MMC for MVDC DAB Converter

Abstract

A modular multilevel converter (MMC) bridge utilizing Quasi-2-Level operation (Q2L) is analyzed in an isolated DC-DC converter. The operation of the DC-DC converter is assimilated to that of a Dual Active Bridge (DAB) converter. Unlike traditional MMC designs, this approach prioritizes the minimization of passive components. Specifically, it is demonstrated that dedicated arm inductors can be replaced by the inherent stray inductance of the interconnections. While this reduction in footprint is advantageous, the combination of reduced arm inductors and small submodule capacitors triggers a resonant circulating current within the DC loop. This resonance can adversely impact Zero-Voltage Switching (ZVS) typically inherent to DAB operation. A strategy is proposed to safeguard ZVS through switching frequency adaptation or passive components design optimization. The proposed analysis is validated experimentally across a switching frequency range of 5 kHz to 12.5 kHz.

José Andrés Aguilar Croston, Ampère, SuperGrid Institute; Jean-Yves Gauthier, CoSMa – Ampère; Cyril Buttay, Ampère; Maryam Saeedifard, ECE GeorgiaTech – School of Electrical and Computer Engineering – Georgia Insitute of Technology; Besar Asllani, SuperGrid Institute; Piotr Dworakowski, SuperGrid Institute

Presented at PCIM Europe; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, Jun 2026, Nuremberg, Germany.

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