Improved droop control based on multi-stage lead-lag compensation

The droop control and virtual synchronous generator control are currently the two most popular inverter control strategies, but both of these control strategies cannot be satisfied at the same time: (1) Frequency stability in stand-alone (SA) mode. (2) In the grid-connected (GC) mode, the output active power quickly follows the input power command. (3) Anti-interference ability of inverter output frequency in gridconnected mode. In response to these deficiencies, this paper proposes an improved droop control based on multi-stage leadlag compensation. This control strategy adds a lag link to the frequency output link of the traditional droop control to provide virtual inertia for the system; multi-stage lead lag compensation is added to the active power output section to improve the dynamic characteristics in the grid-connected mode. In the GC state, the improved droop control effectively reduces the power impact when the power command changes, and accelerates the power response speed. Enhanced the anti-interference ability of output frequency. In SA state, improved droop control can provide sufficient inertia and damping characteristics. Finally, the simulation results verify the effectiveness of the proposed improved droop control.