Use of hybrid active/inactive method to regulate power sharing between parallel ICs in hybrid AC-DC microgrid in the islanding mode

In this paper, using a hybrid control method including an active control method (circular chain) and an inactive control method (droop control), the contribution of each interlinking converter (IC) to the power transmitted between AC and DC subnetworks in islanded mode is determined. The values of real power in AC and DC sub-grids correspond to the frequency of AC sub-grid and the voltage of the DC sub-grid, respectively. Therefore, using this data and defining a droop relation, the value of initial power transmitted between AC and DC subnetworks is determined. Then, the active control system modifies the transmitted power considering the data received from the previous converter. The use of power parameter in the active control method decreases the bandwidth of transmission lines between the converters. On the other hand, two-stage control for determining the value of transmitted power retains the stability of the system in case of a disruption in transmission lines. However, the circular chain control system presented in this paper will continue to operate in case of disruption in the link between two adjacent ICs. The results of simulation in MATLAB confirm the credibility of the mentioned arguments.