Control and performance of modular multilevel converters currents using resonant controller

Recently, Modular Multilevel Converters (MMCs) have received an increasing attention since this topology of converters is a viable solution for high-voltage and high-power applications. However, many research results concerning the control problems of modular multilevel converters have been proposed in the literature which the main control problems are to control the grid and differential currents as energy stored in each sub-modules. This paper deals with the modeling and the control of modular multilevel converters. Since the voltage fluctuations between the arms of each phase introduce circulating currents containing a second harmonic component, which distorts the arm currents and may increase the ripple on capacitor voltages, a control approach based on resonant controller is proposed to eliminate the circulating currents. The effectiveness of the proposed control method is illustrated by numerical simulations and compared with a classical approach commonly used in the literature.