A Proportional Resonator-based control scheme to suppress AC components in circulating current of Modulator Multilevel Converter

The Modular Multilevel Converter (MMC) is an emerging topology in the line of multilevel converters for high and medium voltage applications. This paper proposes the control technique to tackle the pressing issue of ac component in circulating current. By an additional minor loop having Proportional Resonator controller for suppresing ac components in circulating current to zero. With PR control it is also now possible to introduce the output current control. This paper also presents application of antiwind up control with PR to avoid problems like windup or rollover arise in working under saturation or sustained error input. This control can be applied to single phase also as opposed to methods discussed previously. Simulation results are been provided for 3 phase grid connected system, using circulating current control and tracking of output current to be given as feedback signal.