Coordinated Power Mutual Support Control for Multiport Hybrid AC/DC Microgrids

Ensuring the frequency and voltage stability of multi sub-grids are urgent for the hybrid microgrid’s stable operation. In this article, a model predictive control (MPC) based cross-grid power coordinated control strategy is proposed. First, according to the topology of multiport hybrid microgrid, the conventional ac–dc coupling characteristics are analyzed, and a different coupling analysis method considering energy conservation and capacity difference is introduced. Then, the regulation demands when multi sub-grids encounter net power changes are analyzed in detail, based on which the designing principles of the proposed strategy are elaborated. Further, the state space models of ac and dc sub-grids are built separately based on their respective physical characteristics, derived from which the hybrid microgrid model is obtained and serves for the control scheme design. Subsequently, a novel mutual support power control strategy based on MPC is proposed, of which the implementation procedure is elaborated, the key parameters are discussed, and the stability is theoretically analyzed. The proposed strategy can achieve good performance of frequency and voltage regulations with less cross-grid power transmission. The performance of the proposed control strategy is validated by the hardware-in-loop (HIL) experiments based on RT-LAB platform.