A Novel Voltage Event-Triggered Hierarchical Control Strategy in Low-voltage Microgrid

The paper proposes a novel voltage event-triggered P-U control strategy for improving related active power sharing accuracy in low-voltage microgrid (MG). Active power sharing inaccuracy is associated with voltages difference of distributed generation units (DGs) that is basically attributed to mismatched lines impedance. So the inaccuracy is inevitable. The proposed voltage control strategy contains primary control and three-stage secondary control. We take the traditional P-U droop control as primary control and use the event-triggered way in secondary control. Based on the voltage range in case of various loads active demands (LAD), we can design the PI control signal in secondary control and corresponding triggered condition (CTC) of each stage. By restoring DGs voltages in stage 1, synchronizing DGs voltages in stage 2 and using line voltage drop compensation in stage 3, accurate active power sharing can be maintained by adding corresponding control signal to primary control. RT-LAB (a system real-time simulation platform) simulation confirms the effectiveness of proposed voltage control strategy.