A Switched Mid-Point Modular Multilevel Converter for HVDC Applications

The modular multilevel converter (MMC) has emerged as the industry standard for voltage source converters (VSC) based high direct-current (HVDC) applications since its benefits of scalability, modularity, efficiency and better output quality outweigh drawback large energy storage. However, with a growing number offshore HVDC installations, volume footprint converter, which are largely influenced by storage, becoming increasingly critical. This led to rising interest in alternative topologies that reduce storage while maintaining MMC. paper introduces switched mid-point (SMPC), is able generate desired AC-side waveforms significantly less (around 50%) than DC-side free from any distortion requires additional filtering. Reduced associated reduction achieved at expense requiring more switches slightly lower when compared Like many other MMC-style circuits, except operating ‘sweet-spot’, active control balance needed, technique on second harmonic injection proposed. operation proposed scheme verified simulations medium-voltage setup experimentally low-voltage lab-scale prototype.