Autonomous load sharing between converters and generators in microgrids

This paper presents a voltage-power /frequency-reactive power (VP/FQ) cross droop control scheme that allows multiple voltage source converters (VSCs) to operate in parallel with conventional generators in a microgrid. Each current controlled VSC in such a microgrid has its own VP/FQ cross droop 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 reactive power output, multiple VP/FQ cross droop controllers jointly regulate the microgrid voltage while sharing a common reactive load with one another and with conventional generators in the same microgrid. Similarly, by drooping the frequency reference of each controller against its real power output, multiple VP/FQ cross droop controllers jointly regulate the microgrid frequency while sharing the real load. Simulation results are provided to validate the VP/FQ cross droop control scheme.