Small-signal modeling of digitally controlled grid-connected inverters with LCL filters

Xiaotian Zhang, Joseph W. Spencer, Josep M. Guerrero

Research output: Contribution to journalJournal articleResearchpeer-review

124 Citations (Scopus)
2903 Downloads (Pure)

Abstract

When LCL filters are applied to digitally controlled grid-connected inverters, the design of controllers is usually implemented using classic average models. The accuracy of these models in s-domain is only guaranteed in low frequency range. In order to predict the dynamic behaviors, new smallsignal z-domain models are deduced for digitally controlled gridconnected inverters with converter current control scheme and converter current plus grid current control scheme. The proposed methods model the inverters including different delay effects under most possible circumstances, which allows direct design for
controllers in z-domain. The stability boundaries obtained from the root loci of the classic average models and the proposed z-domain models and the discrete state space models are compared to the simulation results, showing that the proposed z-domain models are more effective in predicting instabilities. Experimental results are presented and compared to the average models predictions and z-domain models predictions, which shows the proposed models are capable of predicting the values of control variables at the true sampling instants.
Original languageEnglish
JournalI E E E Transactions on Industrial Electronics
Volume60
Issue number9
Pages (from-to)3752-3765
Number of pages14
ISSN0278-0046
DOIs
Publication statusPublished - Sept 2013

Keywords

  • Average models, digital control, grid-connected inverters, z-domain models.

Fingerprint

Dive into the research topics of 'Small-signal modeling of digitally controlled grid-connected inverters with LCL filters'. Together they form a unique fingerprint.

Cite this