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Design of grid-voltage feedforward to increase impedance of grid-connected three-phase inverters with LCL-filter

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Details

Original languageEnglish
Title of host publicationThe 2016 8th International Power Electronics and Motion Control Conference - ECCE Asia (IPEMC 2016-ECCE Asia)
PublisherIEEE
Pages2675-2682
Number of pages8
ISBN (Print)978-1-5090-1210-7
DOIs
Publication statusPublished - 23 May 2016
Publication typeA4 Article in a conference publication
EventINTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE -
Duration: 1 Jan 1900 → …

Conference

ConferenceINTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE
Period1/01/00 → …

Abstract

Grid-connected three-phase inverters are increasingly used to interface renewable energy sources to distribution networks. From the perspective of power quality the output impedance of the inverter should be as large as possible since inverters are usually operated under output-current control mode. Feedforward from grid voltages has been demonstrated to improve power quality which is an indicator for better impedance behavior. However, the effect of feedforward has not been verified by accurate impedance measurements in the literature. This paper demonstrates the effect of grid voltage feedforward on the output impedance of a three-phase inverter with LCL-filter and proposes an accurate small-signal model to predict the shape of inverter output impedance in the dq-domain. The model can be used in impedance shaping and for evaluating instability caused by impedance-based interactions. Moreover, the ideal feedforward transfer functions are derived and it is shown that the proposed method has the potential to increase the inverter output impedance significantly at the LCL-filter resonant frequency.

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