Hybrid Modular Multilevel Converter for Variable DC Link Voltage Operation

Modular Multilevel Converter (MMC) secured its place in applications where high reliability, efficiency and effortless voltage/power scalability are of paramount importance. Without compromising these benefits, this paper proposes a novel control appropriate design approach for Hybrid-MMC topology, comprising mix Full-Bridge HalfBridge submodules converter branches, as grid-side stage back-to-back MMC, enabling operation at variable DC link voltage arbitrary power factor. In the midst transition to Renewable Energy Sources-dominated systems, opens door use retrofit large Pumped Hydro Storage Plants speed operation, existing machines would not tolerate common-mode stress imposed by fixed-DC-link-voltage operated machine-side MMC stage. way, highly flexible grid-scale energy storage hydro capacities is enabled. additional layers have been developed verified through set test scenarios. Sizing typical operating points compared equally-rated Full-Bridge-based MMC. Improvements over solutions include unity-power-factor entire attainable range equal loading upper lower phase-leg branches regardless poin.