Research on LADRC Based Microgrid Quasi-synchronization Smooth Grid-Connection Method

Abstract

The prerequisite for ensuring the safe and reliable operation of the microgrid is to realize the smooth and fast switching of microgrid between grid-connection and islanding operation. Considering these factors, this paper proposes a kind of smooth grid-connection method of microgrid based on Linear Active Disturbance Rejection Control (LADRC). The voltage and current dual-loop control strategy is adopted. The voltage outer loop is designed as LADRC controller. Comparing with PI controller, it can significantly improve the tracking and disturbance rejection performance. The current inner loop is designed as traditional proportion controller, which can ensure the dynamic ability. Meanwhile, this paper also discusses non-phase-locked loop method of three-phase grid-connected inverter, which is trying to find a novel way on dq0 transformation of three-phase grid voltage. The simulation results show the correctness of the theoretical analysis and the effectiveness of the proposed control strategy.