Dual Active Compensation for Voltage Source Rectifiers Under Very Weak Grid Conditions
DC subgrids consisting of modern active loads (ALs) and local dc distributed generation (DG) units are normally interfaced with the main ac grid by utilizing bidirectional voltage source converters (VSCs). Under the very weak grid (VWG) conditions, the integration of voltage-oriented controlled (VOC...
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| Format: | Article |
| Language: | English |
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IEEE
2021-01-01
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| Series: | IEEE Access |
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| Online Access: | https://ieeexplore.ieee.org/document/9628101/ |
| _version_ | 1818402338421866496 |
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| author | Saeed Rezaee Amr Radwan Mehrdad Moallem Jiacheng Wang |
| author_facet | Saeed Rezaee Amr Radwan Mehrdad Moallem Jiacheng Wang |
| author_sort | Saeed Rezaee |
| collection | DOAJ |
| description | DC subgrids consisting of modern active loads (ALs) and local dc distributed generation (DG) units are normally interfaced with the main ac grid by utilizing bidirectional voltage source converters (VSCs). Under the very weak grid (VWG) conditions, the integration of voltage-oriented controlled (VOC) VSCs in the inversion mode becomes very challenging and therefore undamped oscillations in the power and angle responses are yielded. Most of the existing works address this issue for VSCs in the inversion mode of operation. However, integration of VSCs in the rectification mode with the consideration of the outer loop controllers into the VWGs has not been reported. To fill up this gap, a state-space model of the bidirectional VSC-to-weak grid (VSC-WG) system is developed in this work with an emphasis on the rectification mode of operation. A modal-sensitivity analysis is then utilized to evaluate small-signal stability of the system, identify the dominant modes, and investigate the system states that have a major influence on these modes. The results reveal two pairs of unstable complex modes that are correlated with the dynamic interaction between the VOC-based VSCs and the VWG impedance. It is also shown that the stability margin of VSCs in the rectification mode is less than that of the inversion mode under the same VWG conditions. To enhance the integration of the VSCs in the rectification mode, a dual-active compensation (DAC) scheme is proposed to mitigate the instabilities under VWG conditions. Several time-domain simulation results are presented to verify the validity of the small-signal model and demonstrate the effectiveness of the DAC scheme under the VWG conditions. Finally, hardware-in-the-loop (HIL) real-time experimental results are presented to validate the simulation results. |
| first_indexed | 2024-12-14T08:06:47Z |
| format | Article |
| id | doaj.art-4ce26aad35974e6491412280d653b44f |
| institution | Directory Open Access Journal |
| issn | 2169-3536 |
| language | English |
| last_indexed | 2024-12-14T08:06:47Z |
| publishDate | 2021-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Access |
| spelling | doaj.art-4ce26aad35974e6491412280d653b44f2022-12-21T23:10:10ZengIEEEIEEE Access2169-35362021-01-01916044616046010.1109/ACCESS.2021.31314819628101Dual Active Compensation for Voltage Source Rectifiers Under Very Weak Grid ConditionsSaeed Rezaee0https://orcid.org/0000-0002-0388-1718Amr Radwan1https://orcid.org/0000-0001-5988-0987Mehrdad Moallem2https://orcid.org/0000-0003-4700-7026Jiacheng Wang3https://orcid.org/0000-0002-9395-7252School of Mechatronic Systems Engineering, Simon Fraser University, Surrey, BC, CanadaDepartment of Engineering and Design, Western Washington University, Bellingham, WA, USASchool of Mechatronic Systems Engineering, Simon Fraser University, Surrey, BC, CanadaSchool of Mechatronic Systems Engineering, Simon Fraser University, Surrey, BC, CanadaDC subgrids consisting of modern active loads (ALs) and local dc distributed generation (DG) units are normally interfaced with the main ac grid by utilizing bidirectional voltage source converters (VSCs). Under the very weak grid (VWG) conditions, the integration of voltage-oriented controlled (VOC) VSCs in the inversion mode becomes very challenging and therefore undamped oscillations in the power and angle responses are yielded. Most of the existing works address this issue for VSCs in the inversion mode of operation. However, integration of VSCs in the rectification mode with the consideration of the outer loop controllers into the VWGs has not been reported. To fill up this gap, a state-space model of the bidirectional VSC-to-weak grid (VSC-WG) system is developed in this work with an emphasis on the rectification mode of operation. A modal-sensitivity analysis is then utilized to evaluate small-signal stability of the system, identify the dominant modes, and investigate the system states that have a major influence on these modes. The results reveal two pairs of unstable complex modes that are correlated with the dynamic interaction between the VOC-based VSCs and the VWG impedance. It is also shown that the stability margin of VSCs in the rectification mode is less than that of the inversion mode under the same VWG conditions. To enhance the integration of the VSCs in the rectification mode, a dual-active compensation (DAC) scheme is proposed to mitigate the instabilities under VWG conditions. Several time-domain simulation results are presented to verify the validity of the small-signal model and demonstrate the effectiveness of the DAC scheme under the VWG conditions. Finally, hardware-in-the-loop (HIL) real-time experimental results are presented to validate the simulation results.https://ieeexplore.ieee.org/document/9628101/Dual active compensation (DAC)dynamic interactionrectification modeshort circuit ratio (SCR)small-signal stabilityvoltage source converter (VSC) |
| spellingShingle | Saeed Rezaee Amr Radwan Mehrdad Moallem Jiacheng Wang Dual Active Compensation for Voltage Source Rectifiers Under Very Weak Grid Conditions IEEE Access Dual active compensation (DAC) dynamic interaction rectification mode short circuit ratio (SCR) small-signal stability voltage source converter (VSC) |
| title | Dual Active Compensation for Voltage Source Rectifiers Under Very Weak Grid Conditions |
| title_full | Dual Active Compensation for Voltage Source Rectifiers Under Very Weak Grid Conditions |
| title_fullStr | Dual Active Compensation for Voltage Source Rectifiers Under Very Weak Grid Conditions |
| title_full_unstemmed | Dual Active Compensation for Voltage Source Rectifiers Under Very Weak Grid Conditions |
| title_short | Dual Active Compensation for Voltage Source Rectifiers Under Very Weak Grid Conditions |
| title_sort | dual active compensation for voltage source rectifiers under very weak grid conditions |
| topic | Dual active compensation (DAC) dynamic interaction rectification mode short circuit ratio (SCR) small-signal stability voltage source converter (VSC) |
| url | https://ieeexplore.ieee.org/document/9628101/ |
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