Averaging-based energy balancing controller for modular multilevel converters

Abstract Modular multilevel converters (MMC) play an important role in the energy transition. A cascaded controller using feedback of one-period averages is presented for balancing the energies between the branches of an MMC. For this purpose, a higher-order averaged model of the MMC including the inner current control loop is developed. The stability of the controller is analyzed based on the original non-averaged model, and its performance is validated on a prototype system.