Composite Current-Constrained Control of Stand-Alone Three-Phase Inverters Under Multiple Load Conditions

• Published in: IEEE transactions on power electronics Vol. 39; no. 7; pp. 7876 - 7889
• Main Authors: Huang, Saijin, Wang, Xiangyu, Li, Guanjun, Wang, Xinming, Li, Shihua, Li, Qi
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Benchmarks; Composite control scheme; Constraining; Control systems design; Controllers; current limiting; Disturbance observers; Electric potential; Energy distribution; Harmonic analysis; harmonic suppression; Inverters; Limiting; mismatched disturbances; multiple load conditions; Overcurrent; Power harmonic filters; Power quality; Renewable energy sources; Stability analysis; three-phase inverters; Unbalance; Voltage; Voltage control; voltage regulation
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2024.3380322

With the growing penetration of renewable energy sources, distribution network protection and stability are of great importance. This article aims to propose a current limiting control scheme with antidisturbance properties to improve the reliability and power quality of stand-alone three-phase inverters under multiple load conditions (including balanced loads, unbalanced loads, and nonlinear loads). A benchmark controller is designed first to achieve voltage regulation and overcurrent protection targets under relatively ideal conditions (e.g., only subject to constant disturbances caused by parameter perturbation or linear balanced load switching). Then, considering the unbalanced and nonlinear load conditions, two composite disturbance observers are constructed to estimate the large-scale, fast-varying harmonic disturbances introduced by the multiple loads. Based on the disturbance estimates and the benchmark controller, a composite current-constrained control scheme with rigorous stability analyses is proposed. The innovative control scheme ensures good output voltage quality and strictly guarantees overcurrent protection, which is validated by the simulations and experiments. Last but not least, extended current limiting control schemes to broaden the application range and enhance the control performance are presented.