Reaction of grid-connected converters to unbalanced grid voltages with focus on modular multilevel converters

The topology and the resulting properties of power-electronic converters influence mitigation concepts for undesirable power oscillations in the connected assets. Power theory in general provides an answer for the optimal way to operate under aspects of efficient energy transmission. However, practical aspects and design considerations (including size and cost) as well as grid-code specifications also influence the chosen technical solution. With this background, control objectives have to be related to the technical options available and the demands given by e.g. grid codes.