A novel Decoupled Trigonometric Saturated droop controller for power sharing in islanded low-voltage microgrids

This paper proposes a novel droop control based on Decoupled Trigonometric Saturated (DTS) controller for stable power sharing applied to meshed parallel inverter systems in islanded microgrids. The novel DTS control scheme is introduced to improve the power-sharing accuracy with a better stability and to provide a proper dynamic decoupling of active and reactive power in the presence of different impedances. Moreover, this method not only achieves the aforementioned decoupling; but also, guarantees both voltage and frequency stability. The theoretical concept of the proposed novel droop control strategy is presented in detail. The DTS controller is applied to a common AC bus microgrid structure and a meshed parallel inverter system structure in islanded microgrids with mainly inductive or resistive line impedances. An offline time-domain simulation is conducted in MATLAB®/SimPowerSystems environment using RT-EVENTS toolbox from OPAL-RT to model the inverters. Resulting waveforms from a three-phase microgrid with four distributed generators are presented along with a comparison against the conventional droop control strategy and show the effectiveness of the proposed method in allocating both real and reactive power.