An information/power fusion coordinated control framework for bipolar DC microgrids

In this paper, an information/power fusion coordinated secondary control strategy based on power line communication is proposed to realize the full-domain current balancing and bus voltage regulation of bipolar DC microgrid. Firstly, the information/power coordinated control strategy with AC signals is designed to realize the secondary control objective by using the AC signal frequency information superimposed on the DC voltage to transmit the unified voltage feedback signal. On this basis, to address the drawbacks of insufficient system stability margin and poor dynamic characteristics when the common voltage estimate is directly used as the feedback signal, an improved feedback structure combining the estimated voltage information and the local voltage information is proposed to enhance the robustness of the system toward the communication delay. In addition, the effects of controller parameters and control strategies on the system dynamics are investigated by establishing a small-signal model of the system. Finally, a bipolar DC microgrid experimental platform is established for validation, and the results show that the proposed control strategy can realize the control objectives under complex operating conditions.