A generalized power control approach in ABC frame for modular multilevel converters based on Lagrange multipliers

This work presents a generalized and versatile control approach for Modular Multilevel Converters using Lagrange Multipliers in the ABC frame. The methodology is capable of analytically obtaining desired operative conditions by calculating the differential current references previously established by the constraints in the optimization formulation, whilst obtaining the result with minimum I) differential current oscillations (Δi_diffk), or II) capacitive phase energy oscillations (Δw_Σk). Furthermore, the energy distribution inside the MMC; i.e., the capacitive phase average energy sum (w_Σk) and difference (w_Δk), is being regulated by means of the constraint definitions.