A hierarchical approach for frequency regulation in islanded inverter-based microgrids

This paper represents a hierarchical frequency regulation in an islanded inverter-based microgrid. The role of Microgrid Central Controller (MGCC) and droop controllers as the first and second hierarchical control levels in islanded microgrids is decribed. The control of voltage and frequency of an islanded inverter including Phase-locked loop (PLL), voltage controller, current controller and frequency controller is illustrated in detail. The effectiveness of proposed control strategy is demonstrated throurh a test system including three 10-kVA Voltage Source Inverters (VSIs) that is simulated in PSCAD/EMTDC software.