Decoupled droop control of inverters

This article first reviews the droop control method for inverters participating in low voltage microgrids, discussing static and dynamic response. Then the paper proposes a droop controller that brings independent actuation of frequency over active power and voltage over reactive power. The method is based on the application of a matrix filter that decouples dynamic actuation and reduces the multivariable system to two independent single input-single output systems. The results of static, dynamic and robustness analysis are given, with a discussion of simulation results. An advantage of this method is that the control loop can be stabilized and tuned by specifics gain parameters that are independent of the droop coefficients and of the coupling impedance of the inverter with the grid. It thus offers maximum freedom and flexibility for adjusting the static and dynamic behavior of droop control.