An Optimization Method to Reducing the Internal Circulating Current for eMACP-MMC

The integration of distributed energy resources (DERs) and dc loads with significant power fluctuations presents critical challenges to conventional distribution networks (DNs), threatening power quality and reliability. Soft normally open points (SNOPs), based on power electronic devices, have emerged as an effective solution by replacing traditional tie switches, enabling precise control of active and reactive power, and improving feeder voltage regulation. Back-to-back modular multilevel converters (BTB-MMCs) have been widely adopted as SNOPs due to their modularity and scalability. However, the need for multiple full-power-rated converters results in high costs and large footprints, limiting widespread adoption. To address this, an enhanced modular multilevel converter with multiple ac ports (eMACP-MMC) which is more economic and lightweight has been proposed, though their operation introduces circulating currents, increasing losses and stress. This paper presents an optimization method to minimize circulating currents by leveraging the system's redundant degrees of freedom, enhancing efficiency and performance.