{'fraction_non_alphanumeric': 0.03656307129798903, 'fraction_numerical': 0.0, 'mean_word_length': 5.11731843575419, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Grid-Current-Feedback Control for LCL-Filtered Grid Converters With Enhanced Stability

This paper proposes a second-order-generalized-integrator (SOGI)-based time-delay compensation method for extending the stable region of a dual-loop grid-current-feedback (GCF) control system. According to the analysis, stable region of the dual-loop system should be designed below a certain critical frequency, before time-delay compensation method can be applied. To always meet the requirement, relationship between single-loop converter-current-feedback and dual-loop GCF control is clarified, before a robust inner-loop gain for the dual-loop GCF scheme is determined. Enforcing this gain allows the converter to remain in its stable region, regardless of how its LCL -filter parameters and grid impedance vary. The SOGI-based delay compensation method can then be applied for widening the stable region of the dual-loop GCF scheme, as proven through s-domain Bode diagrams and z -domain root loci. These theoretical proofs are eventually validated by experimental results obtained in the laboratory.