An Improved Active Damping Method for Enhancing Robustness of LCL-Type, Grid-Tied Inverters under Weak Grid Conditions
The conventional proportional-gain-feedback link can only obtain the smallest effective damping region (EDR) due to the control delay among all the active damping methods regarding the capacitor current feedback. The digitally controlled system tends to be unstable when the system resonant frequency...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-09-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/23/19/8203 |
| _version_ | 1797575138945794048 |
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| author | Shanwen Ke Yuren Li |
| author_facet | Shanwen Ke Yuren Li |
| author_sort | Shanwen Ke |
| collection | DOAJ |
| description | The conventional proportional-gain-feedback link can only obtain the smallest effective damping region (EDR) due to the control delay among all the active damping methods regarding the capacitor current feedback. The digitally controlled system tends to be unstable when the system resonant frequency reaches the critical frequency caused by the grid impedance variation. To weaken the adverse effect on the system caused by the control delay, phase-lead feedback links are applied along the feedback path to provide phase compensation. By taking the simplicity and reliability of the feedback links into account, this paper proposes an alternative to an ideal differentiator, which consists of the Tustin discrete form of ‘<i>s</i>’ and a digital low-pass filter. This proposed method has an identical phase frequency characteristic as an ideal differentiator but a better magnitude frequency characteristic, and its EDR can reach [0, <i>f</i><sub>s</sub>/3]. The system stability analysis is conducted under different resonant frequencies, and under the condition of a weak grid, the co-design approach of the active damper and digital controller is presented. Finally, the experimental results are shown to verify the proposed method. |
| first_indexed | 2024-03-10T21:34:17Z |
| format | Article |
| id | doaj.art-36bf69bcd5f44a7caaac08a3a71f0ba0 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T21:34:17Z |
| publishDate | 2023-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-36bf69bcd5f44a7caaac08a3a71f0ba02023-11-19T15:04:13ZengMDPI AGSensors1424-82202023-09-012319820310.3390/s23198203An Improved Active Damping Method for Enhancing Robustness of LCL-Type, Grid-Tied Inverters under Weak Grid ConditionsShanwen Ke0Yuren Li1School of Automation, Northwestern Polytechnical University, Xi’an 710129, ChinaSchool of Automation, Northwestern Polytechnical University, Xi’an 710129, ChinaThe conventional proportional-gain-feedback link can only obtain the smallest effective damping region (EDR) due to the control delay among all the active damping methods regarding the capacitor current feedback. The digitally controlled system tends to be unstable when the system resonant frequency reaches the critical frequency caused by the grid impedance variation. To weaken the adverse effect on the system caused by the control delay, phase-lead feedback links are applied along the feedback path to provide phase compensation. By taking the simplicity and reliability of the feedback links into account, this paper proposes an alternative to an ideal differentiator, which consists of the Tustin discrete form of ‘<i>s</i>’ and a digital low-pass filter. This proposed method has an identical phase frequency characteristic as an ideal differentiator but a better magnitude frequency characteristic, and its EDR can reach [0, <i>f</i><sub>s</sub>/3]. The system stability analysis is conducted under different resonant frequencies, and under the condition of a weak grid, the co-design approach of the active damper and digital controller is presented. Finally, the experimental results are shown to verify the proposed method.https://www.mdpi.com/1424-8220/23/19/8203LCL filterideal differentiatordigital low-pass filterdigital controlactive damping |
| spellingShingle | Shanwen Ke Yuren Li An Improved Active Damping Method for Enhancing Robustness of LCL-Type, Grid-Tied Inverters under Weak Grid Conditions Sensors LCL filter ideal differentiator digital low-pass filter digital control active damping |
| title | An Improved Active Damping Method for Enhancing Robustness of LCL-Type, Grid-Tied Inverters under Weak Grid Conditions |
| title_full | An Improved Active Damping Method for Enhancing Robustness of LCL-Type, Grid-Tied Inverters under Weak Grid Conditions |
| title_fullStr | An Improved Active Damping Method for Enhancing Robustness of LCL-Type, Grid-Tied Inverters under Weak Grid Conditions |
| title_full_unstemmed | An Improved Active Damping Method for Enhancing Robustness of LCL-Type, Grid-Tied Inverters under Weak Grid Conditions |
| title_short | An Improved Active Damping Method for Enhancing Robustness of LCL-Type, Grid-Tied Inverters under Weak Grid Conditions |
| title_sort | improved active damping method for enhancing robustness of lcl type grid tied inverters under weak grid conditions |
| topic | LCL filter ideal differentiator digital low-pass filter digital control active damping |
| url | https://www.mdpi.com/1424-8220/23/19/8203 |
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