Please use this identifier to cite or link to this item: http://localhost/handle/Hannan/652661
Title: Grid-Current-Feedback Active Damping for LCL Resonance in Grid-Connected Voltage-Source Converters
Authors: Xiongfei Wang;Frede Blaabjerg;Poh Chiang Loh
subject: virtual impedance;Voltage source converter;non-minimum phase system;LCL filter;resonance damping
Year: 2016
Publisher: IEEE
Abstract: This paper investigates active damping of LCL-filter resonance in a grid-connected voltage-source converter with only grid-current feedback control. Basic analysis in the s-domain shows that the proposed damping technique with a negative high-pass filter along its damping path is equivalent to adding a virtual impedance across the grid-side inductance. This added impedance is more precisely represented by a series RL branch in parallel with a negative inductance. The negative inductance helps to mitigate phase lag caused by time delays found in a digitally controlled system. The mitigation of phase-lag, in turn, helps to shrink the region of nonminimum-phase behavior caused by negative virtual resistance inserted unintentionally by most digitally implemented active damping techniques. The presented high-pass-filtered active damping technique with a single grid-current feedback loop is thus a more effective technique, whose systematic design in the z-domain has been developed in this paper. For verification, experimental testing has been performed with results obtained matching the theoretical expectations closely.
URI: http://localhost/handle/Hannan/136888
http://localhost/handle/Hannan/652661
ISSN: 0885-8993
1941-0107
volume: 31
issue: 1
Appears in Collections:2016

Files in This Item:
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7058352.pdf1.69 MBAdobe PDFThumbnail
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Title: Grid-Current-Feedback Active Damping for LCL Resonance in Grid-Connected Voltage-Source Converters
Authors: Xiongfei Wang;Frede Blaabjerg;Poh Chiang Loh
subject: virtual impedance;Voltage source converter;non-minimum phase system;LCL filter;resonance damping
Year: 2016
Publisher: IEEE
Abstract: This paper investigates active damping of LCL-filter resonance in a grid-connected voltage-source converter with only grid-current feedback control. Basic analysis in the s-domain shows that the proposed damping technique with a negative high-pass filter along its damping path is equivalent to adding a virtual impedance across the grid-side inductance. This added impedance is more precisely represented by a series RL branch in parallel with a negative inductance. The negative inductance helps to mitigate phase lag caused by time delays found in a digitally controlled system. The mitigation of phase-lag, in turn, helps to shrink the region of nonminimum-phase behavior caused by negative virtual resistance inserted unintentionally by most digitally implemented active damping techniques. The presented high-pass-filtered active damping technique with a single grid-current feedback loop is thus a more effective technique, whose systematic design in the z-domain has been developed in this paper. For verification, experimental testing has been performed with results obtained matching the theoretical expectations closely.
URI: http://localhost/handle/Hannan/136888
http://localhost/handle/Hannan/652661
ISSN: 0885-8993
1941-0107
volume: 31
issue: 1
Appears in Collections:2016

Files in This Item:
File Description SizeFormat 
7058352.pdf1.69 MBAdobe PDFThumbnail
Preview File
Title: Grid-Current-Feedback Active Damping for LCL Resonance in Grid-Connected Voltage-Source Converters
Authors: Xiongfei Wang;Frede Blaabjerg;Poh Chiang Loh
subject: virtual impedance;Voltage source converter;non-minimum phase system;LCL filter;resonance damping
Year: 2016
Publisher: IEEE
Abstract: This paper investigates active damping of LCL-filter resonance in a grid-connected voltage-source converter with only grid-current feedback control. Basic analysis in the s-domain shows that the proposed damping technique with a negative high-pass filter along its damping path is equivalent to adding a virtual impedance across the grid-side inductance. This added impedance is more precisely represented by a series RL branch in parallel with a negative inductance. The negative inductance helps to mitigate phase lag caused by time delays found in a digitally controlled system. The mitigation of phase-lag, in turn, helps to shrink the region of nonminimum-phase behavior caused by negative virtual resistance inserted unintentionally by most digitally implemented active damping techniques. The presented high-pass-filtered active damping technique with a single grid-current feedback loop is thus a more effective technique, whose systematic design in the z-domain has been developed in this paper. For verification, experimental testing has been performed with results obtained matching the theoretical expectations closely.
URI: http://localhost/handle/Hannan/136888
http://localhost/handle/Hannan/652661
ISSN: 0885-8993
1941-0107
volume: 31
issue: 1
Appears in Collections:2016

Files in This Item:
File Description SizeFormat 
7058352.pdf1.69 MBAdobe PDFThumbnail
Preview File