In this simulation, microgrid consists of three VSCs which are connected to different loads. Each VSC consists of a droop controller along with outer voltage controller and inner current controller.
Droop originates from the principle of power balance in synchronous generators. An imbalance between the input mechanical power and the output electric power causes a change in the rotor speed and electrical frequency. Similarly, variation in output reactive power results in voltage magnitude deviation.
Such a characteristic can be artificially created for electronically interfaced inverter-based AC microgrid. In droop control, the relationships between real power and frequency and reactive power and voltage are as follows: