Abstract
This paper proposes a Second-Order-Generalized- Integrator (SOGI)-based time delay compensation method for extending the stable region of 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 dualloop 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 SOGIbased 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.
Original language | English |
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Journal | I E E E Transactions on Power Electronics |
Volume | 32 |
Issue number | 4 |
Pages (from-to) | 3216 - 3228 |
Number of pages | 13 |
ISSN | 0885-8993 |
DOIs | |
Publication status | Published - Apr 2017 |
Keywords
- Stability
- Current control
- Active damping
- LCL-filter
- Voltage-source converter