Performance improvement of the droop control for single-phase inverters

The droop control uses the local average values of the active and reactive power components for sharing the load power demand among inverters in parallel. In this paper, a method that uses a virtual quadrature reference frame to calculate the average power components injected by single-phase inverters is presented. This method improves the dynamic response of the power sharing control, as well as, completely eliminates the double frequency oscillation over the voltage and frequency synthesized by the inverter in steady state. Moreover, it is able to deal with nonlinear loads since the harmonic components that appears in the instantaneous power are filtered. The method is compared with the classical method, which is based on low pass filters, through simulation carried out in Matlab/Simulink and experimental results.