Frequency and Voltage Restoration for Droop Controlled AC Microgrids

Voltage source inverters in islanded microgrids grant active and reactive power sharing. Droop control is widely used due to its simplicity and lack of need for communication. Loads in droop-based microgrids drive the system frequency and voltage up and down. In this paper, a modified droop control to restore the frequency and voltage for an islanded microgrid is presented. Two new terms are introduced to the droop control to eliminate the frequency and voltage mismatches caused by the loads. Also, power sharing between multiple inverters feeding various loads is studied. To ensure precise active and reactive power sharing between the inverters, tuned droop control is analyzed and implemented. MATLAB/Simulink is used to demonstrate the effectiveness of the proposed technique for a microgrid model.