Model predictive control for distributed microgrid system with unbalanced loads

Abstract

The negative sequence (NS) current and voltage unbalance in microgrids will cause the error action of protection device, power loss and equipment damage due to unbalanced loads. To compensate the NS current and limit the voltage unbalance, a novel parallel distributed model predictive control (DMPC) strategy is introduced by communicating between neighboring distributed energy resources (DERs). The paper also presents a NS current sharing strategy to decrease the voltage unbalance and offer reference signals for DMPC according to the maximum NS current of DERs. Through this control structure, it is assured that the NS current is picked up by all DERs within the limit and the voltage unbalance is reduced. The simulation results show DERs share the NS current properly and the voltage unbalance is below 2%, which demonstrate the effectiveness of the control structure.