A Robust Finite-Time Control Strategy for a Three-Phase Inverter With LC Filter Under Uncertain Disturbances

The three-phase inverter is one of the critical components in microgrids and distributed generation systems. The design of a high-performance control system for three-phase inverters is profoundly challenged by abrupt load variations and uncertainties in system parameters. To achieve fast and accurate voltage tracking under parameter uncertainties and load disturbances, this paper proposes a practical robust control scheme combining finite-time disturbance observer and finite-time control (FTC) techniques. In contrast to conventional control schemes employing load current observers, the extended finite-time disturbance observer is designed to achieve rapid finite-time estimation of lumped disturbances caused by load variations and parameter uncertainties. Meanwhile, a robust FTC scheme is proposed, which employs a continuous nonsingular terminal form to eliminate chattering and achieve tracking of the reference voltage within a finite time. The finite-time stability of the entire closed-loop system is proven based on Lyapunov theory. Compared with traditional methods, the proposed method has a faster dynamic response and a better performance in the suppression of disturbances, while requiring no additional sensors to increase costs. Finally, simulations and experiments are performed on a three-phase inverter hardware test platform with the StarSim rapid control prototype. The effectiveness of the proposed control strategy is verified with the experimental results.