Digital capacitor charge balance control strategy of bidirectional DC/DC converter in DC microgrid

DC microgrids (MGs) have many potential advantages compared with AC microgrids, which have attracted more and more attention in recent years. However, DC bus voltage control of these systems can be an important issue undergoing the power surplus or deficit. An energy buffer in the DC MG powered by the bidirectional DC/DC converter with energy storage systems (ESS) such as super capacitor were investigated. In this paper, a novel hybrid control algorithm based on capacitor charge balance control (CBC) for the bidirectional DC/DC converter to achieve near-optimal dynamic performance is presented. A hybrid control strategy is proposed in order to make the DC MG recover from a sudden bus current step change with the smallest voltage deviation in the shortest settling time. And a set of equations are developed to design the proposed hybrid controller. The effectiveness and the fast transient performance of the proposed hybrid approach has been verified by PSIM simulation results.