Adaptive Voltage Compensation and Recovery Strategy for Improving Power Sharing in Island Microgrids

In microgrids with different voltage levels, the difference in line parameters leads to the fact that the output power of the inverter cannot be divided accurately. The traditional droop control cannot solve this problem well. To this end, this paper proposes adaptive voltage compensation and recovery strategy to power sharing control for multi-voltage level microgrid. Firstly, by introducing virtual impedance, the total impedance of inverter system at high/low voltage levels is inductive/resistive. Secondly, by comparing and analyzing the influence of virtual impedance parameters on the total output impedance of the system, the appropriate control parameters are selected. Then, an adaptive voltage compensation module is introduced in the improved droop control, so as to eliminate the deviation between the system output voltages and achieve accurate equalization of reactive/active power. On the other hand, a voltage recovery mechanism is introduced to prevent the inverter output voltage from exceeding the rated range. Finally, the effectiveness of the proposed strategy is verified by experiments.