LADRC-MPC strategy for three-level UPQC

Given the complexity of the unified power quality conditioner (UPQC) system and the difficulty in its control, a single control strategy is no longer sufficient to address various faults in the power grid system. Consequently, a hybrid control strategy combining linear active disturbance rejection control (LADRC) and model predictive control (MPC) is employed in this paper. The LADRC strategy is used in the voltage outer loop control to enhance the system′s rapid response and disturbance rejection capabilities, providing a accurate reference current signal for the current inner loop. In the current inner loop, the current MPC strategy further improves tracking performance and system robustness. The partitioning of the space voltage vector in model prediction is optimized to reduce the controller′s computational load, thereby improving computation speed while ensuring the quality of the output current. Finally, the system is modeled and simulated on the MATLAB/Simulink simulation platform. The results validate that the LADRC-MPC control strategy effectively compensates for comprehensive power quality issues such as grid voltage sags/surges, current distortion, and harmonic pollution caused by load imbalance. It also enhances the voltage support capability of the grid.