Mathematical modelling and stability analysis for grid-connected cascaded H-bridge converter
When power converters are employed to connect the renewable power resources to the grid, the grid inductance can typically be quite significant because wind farms and solar power stations are located far away from the converters. The non-negligible grid inductance interacts with the Phase Locked Loo...
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| Format: | Thesis (University of Nottingham only) |
| Language: | English |
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2018
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| Online Access: | https://eprints.nottingham.ac.uk/55751/ |
| _version_ | 1848799208626192384 |
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| author | Bai, Xiaoyi |
| author_facet | Bai, Xiaoyi |
| author_sort | Bai, Xiaoyi |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | When power converters are employed to connect the renewable power resources to the grid, the grid inductance can typically be quite significant because wind farms and solar power stations are located far away from the converters. The non-negligible grid inductance interacts with the Phase Locked Loop (PLL) which is assisting the grid side current controller with the phase angle of grid voltage and furthermore interacts with the DC-link voltage controller. It is known that the inductance of the grid side transmission line would distort the input voltage of PLL at the point of common coupling and this interference can even lead to the instability of the converter operation. However, the accurate prediction of the stability thresholds of the PLL configuration related to the grid inductance was missing which requires advanced modelling techniques.
The key technique is a new mathematical approach to calculating the spectra, which is more sophisticated and more flexible than existing methods. The Harmonic Balance Technique is powerful for modelling the steady state of the periodic waveform and is already a sophisticated technique in other fields but occasionally adopted on power electronics. This study aims to adopt this modelling approach to obtain a detailed description of the operation of the converter steady state thus the stability of its steady state can be investigated.
The stability analysis is conducted for the periodic steady state employing the Floquet theorem. The stability analysis indicates that for a single-phase grid-connected cascaded H-bridge rectifier, the interactions between control loops and PLL can be affected by grid side inductance, and their interactions can even lead to instability of the system. Notably, the instability boundaries are predicted for PLL bandwidth about three different grid strengths. These thresholds have been verified with both simulation and experimental results. |
| first_indexed | 2025-11-14T20:32:01Z |
| format | Thesis (University of Nottingham only) |
| id | nottingham-55751 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T20:32:01Z |
| publishDate | 2018 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-557512025-02-28T14:20:02Z https://eprints.nottingham.ac.uk/55751/ Mathematical modelling and stability analysis for grid-connected cascaded H-bridge converter Bai, Xiaoyi When power converters are employed to connect the renewable power resources to the grid, the grid inductance can typically be quite significant because wind farms and solar power stations are located far away from the converters. The non-negligible grid inductance interacts with the Phase Locked Loop (PLL) which is assisting the grid side current controller with the phase angle of grid voltage and furthermore interacts with the DC-link voltage controller. It is known that the inductance of the grid side transmission line would distort the input voltage of PLL at the point of common coupling and this interference can even lead to the instability of the converter operation. However, the accurate prediction of the stability thresholds of the PLL configuration related to the grid inductance was missing which requires advanced modelling techniques. The key technique is a new mathematical approach to calculating the spectra, which is more sophisticated and more flexible than existing methods. The Harmonic Balance Technique is powerful for modelling the steady state of the periodic waveform and is already a sophisticated technique in other fields but occasionally adopted on power electronics. This study aims to adopt this modelling approach to obtain a detailed description of the operation of the converter steady state thus the stability of its steady state can be investigated. The stability analysis is conducted for the periodic steady state employing the Floquet theorem. The stability analysis indicates that for a single-phase grid-connected cascaded H-bridge rectifier, the interactions between control loops and PLL can be affected by grid side inductance, and their interactions can even lead to instability of the system. Notably, the instability boundaries are predicted for PLL bandwidth about three different grid strengths. These thresholds have been verified with both simulation and experimental results. 2018-07-18 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/55751/1/PhDThesis16122018.pdf Bai, Xiaoyi (2018) Mathematical modelling and stability analysis for grid-connected cascaded H-bridge converter. PhD thesis, University of Nottingham. mathematical modelling; grid inductance; cascaded H-bridge converters |
| spellingShingle | mathematical modelling; grid inductance; cascaded H-bridge converters Bai, Xiaoyi Mathematical modelling and stability analysis for grid-connected cascaded H-bridge converter |
| title | Mathematical modelling and stability analysis for grid-connected cascaded H-bridge converter |
| title_full | Mathematical modelling and stability analysis for grid-connected cascaded H-bridge converter |
| title_fullStr | Mathematical modelling and stability analysis for grid-connected cascaded H-bridge converter |
| title_full_unstemmed | Mathematical modelling and stability analysis for grid-connected cascaded H-bridge converter |
| title_short | Mathematical modelling and stability analysis for grid-connected cascaded H-bridge converter |
| title_sort | mathematical modelling and stability analysis for grid-connected cascaded h-bridge converter |
| topic | mathematical modelling; grid inductance; cascaded H-bridge converters |
| url | https://eprints.nottingham.ac.uk/55751/ |