Control and power management of converter fed microgrids

This paper presents a voltage-power droop/frequency-reactive power boost (VPD/FQB) control scheme that allows multiple voltage source converters (VSCs) to operate in parallel in a VSC fed microgrid. Each current controlled VSC in such a microgrid has its own VPD/FQB controller that sets its current references to regulate the voltage and frequency of a common microgrid bus. By drooping the voltage reference of each controller against its real power output, multiple VPD/FQB controllers jointly regulate the microgrid voltage while sharing a common load power in proportion to a predetermined ratio. Similarly, by boosting the frequency reference of each controller against its reactive power output, multiple VPD/FQB controllers jointly regulate the microgrid frequency while sharing the reactive load in proportion to a predetermined ratio. The proposed control scheme can also operate in grid connected mode. Experimental results are provided to validate the VPD/FQB control scheme. Index Terms--dq-frame current control, frequency boost, instantaneous synchronization, load sharing, microgrid control, voltage droop, voltage source converter.