A Disturbance Rejection Control Strategy for Droop-Controlled Inverter Based on Super-Twisting Algorithm

In distributed generation systems, multiple inverters paralleled operation is essential for the power requirement of local loads. To achieve the reasonable power distribution among the inverters, droop control is an effective method for the paralleled operation systems without the control interconnection. In general, the multi-loop control structure is usually utilized to regulate the drooped voltage across local loads. However, by using the traditional multi-loop controller, such as proportional-integral and proportional-resonant controllers, the dynamic process of load variation or mode transfer is slow, even the voltage overshoot or drop may occur. To address the above issues, a compact control structure-based super-twisting algorithm has been proposed in this paper. Benefitting from the designed sliding mode controllers, the dynamic response, the load disturbance rejection, and reference tracking performance can be improved. In addition, the robustness to parameters mismatch can also be achieved by using the proposed control method. The comparative simulation and experimental results validate the correctness and feasibility of the proposed method.