Robust H∞ controller based on linear matrix inequalities for grid‑connected inverters in weak grids

Fanqing Zhou; Donghui Li; Ningyi Liang

Robust H∞ controller based on linear matrix inequalities for grid‑connected inverters in weak grids

Fanqing Zhou

Donghui Li

Ningyi Liang

Vol. 23, No. 10, pp. 1496-1506, Oct. 2023

10.1007/s43236-023-00648-6

Grid-connected inverter

Linear matrix inequalities

Robust H∞ controller

Weak grid

Abstract

The problems of grid impedance fluctuations and harmonic interference exist widely in grid-connected inverter systems in a weak grid. A robust H∞ control strategy based on linear matrix inequalities (LMIs) is proposed to solve these problems. The proposed strategy improves the adaptation of inverters to a weak grid and the quality of the grid output current. First, an LCL-type grid-connected inverter model with a resonant controller is established. A reduced-order generalized integrator ensures zero-error tracking of grid current and grid harmonics suppression in the resonant controller. The inverter model, delayed session and resonant controller model are integrated into a polytopic model that describes an uncertain system. Then, a robust H∞ controller is designed to control the integrated polytopic uncertainty model based on LMIs. A suitable optimization condition is designed for the controller gain to avoid violent oscillations of the system. Finally, a hardware-in-the-loop experiment is performed to validate the effectiveness of the suggested approach.

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Cite this article

[IEEE Style]

F. Zhou, D. Li, N. Liang, "Robust H∞ controller based on linear matrix inequalities for grid‑connected inverters in weak grids," Journal of Power Electronics, vol. 23, no. 10, pp. 1496-1506, 2023. DOI: 10.1007/s43236-023-00648-6.

[ACM Style]

Fanqing Zhou, Donghui Li, and Ningyi Liang. 2023. Robust H∞ controller based on linear matrix inequalities for grid‑connected inverters in weak grids. Journal of Power Electronics, 23, 10, (2023), 1496-1506. DOI: 10.1007/s43236-023-00648-6.