Energy-based and non-energy-based control strategies for modular multilevel converters with embedded energy storage

This paper deals with a high voltage direct current (HVDC) system based on modular multilevel converter (MMC) with embedded energy storage capacity. The dynamic behavior of energy-based (EBC) and non-energy-based (NEBC) controls is analyzed and compared for balanced and unbalanced energy storage distribution. EMTP simulations results show an equivalent performance for both controls when energy storage is balanced. While the NEBC control highlights limitations for unbalanced energy storage management, the EBC shows satisfactory overall performance.