Parallel pv configuration with magnetic-free switched capacitor module-level converters for partial shading conditions
Parallel pv configuration with magnetic-free switched capacitor module-level converters for partial shading conditions
In this paper, a module-level photovoltaic (PV) architecture in parallel configuration is introduced for maximum power extraction, under partial shading (PS) conditions. For the first time, a non-regulated switched capacitor (SC) nX converter is a used at the PV-side conversion stage, whose purpose is just to multiply the PV voltage by a fixed ratio and accordingly reduce the input current. All the control functions, including the maximum power point tracking, are transferred to the grid-side inverter. The voltage-multiplied PV modules (VMPVs) are connected in parallel to a common DC-bus, which offers expandability to the system and eliminates the PS issues of a typical string architecture. The advantage of the proposed approach is that the PV-side converter is relieved of bulky capacitors, filters, controllers and voltage/current sensors, allowing for a more compact and efficient conversion stage, compared to conventional per-module systems, such as microinverters. The proposed configuration was initially simulated in a 5 kW residential PV system and compared against conventional PV arrangements. For the experimental validation, a 10X Gallium Nitride (GaN) converter prototype was developed with a flat conversion efficiency of 96.3% throughout the power range. This is particularly advantageous, given the power production variability of PV generators. Subsequently, the VMPV architecture was tested on a two-module 500 WP prototype, exhibiting an excellent power extraction efficiency of over 99.7% under PS conditions and minimal DC-bus voltage variation of 3%, leading to a higher total system efficiency compared to most state-of-the-art configurations.
Gallium nitride, Magnetic-free converters, Module-level converters, Parallel architecture, Partial shading, Photovoltaic systems, Switched capacitor converters
Kampitsis, Georgios
4bba7bcf-6422-4bf9-8996-528e7da1984e
Batzelis, Efstratios
2a85086e-e403-443c-81a6-e3b4ee16ae5e
van Erp, Remco
b880a0f6-219b-4a24-b16c-75ee43b55941
Matioli, Elison
0258a34f-3d4f-45af-a2ff-a39d4656ee39
15 January 2021
Kampitsis, Georgios
4bba7bcf-6422-4bf9-8996-528e7da1984e
Batzelis, Efstratios
2a85086e-e403-443c-81a6-e3b4ee16ae5e
van Erp, Remco
b880a0f6-219b-4a24-b16c-75ee43b55941
Matioli, Elison
0258a34f-3d4f-45af-a2ff-a39d4656ee39
Kampitsis, Georgios, Batzelis, Efstratios, van Erp, Remco and Matioli, Elison
(2021)
Parallel pv configuration with magnetic-free switched capacitor module-level converters for partial shading conditions.
Energies, 14 (2), [456].
(doi:10.3390/en14020456).
Abstract
In this paper, a module-level photovoltaic (PV) architecture in parallel configuration is introduced for maximum power extraction, under partial shading (PS) conditions. For the first time, a non-regulated switched capacitor (SC) nX converter is a used at the PV-side conversion stage, whose purpose is just to multiply the PV voltage by a fixed ratio and accordingly reduce the input current. All the control functions, including the maximum power point tracking, are transferred to the grid-side inverter. The voltage-multiplied PV modules (VMPVs) are connected in parallel to a common DC-bus, which offers expandability to the system and eliminates the PS issues of a typical string architecture. The advantage of the proposed approach is that the PV-side converter is relieved of bulky capacitors, filters, controllers and voltage/current sensors, allowing for a more compact and efficient conversion stage, compared to conventional per-module systems, such as microinverters. The proposed configuration was initially simulated in a 5 kW residential PV system and compared against conventional PV arrangements. For the experimental validation, a 10X Gallium Nitride (GaN) converter prototype was developed with a flat conversion efficiency of 96.3% throughout the power range. This is particularly advantageous, given the power production variability of PV generators. Subsequently, the VMPV architecture was tested on a two-module 500 WP prototype, exhibiting an excellent power extraction efficiency of over 99.7% under PS conditions and minimal DC-bus voltage variation of 3%, leading to a higher total system efficiency compared to most state-of-the-art configurations.
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energies-14-00456-v2
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More information
Accepted/In Press date: 11 January 2021
e-pub ahead of print date: 15 January 2021
Published date: 15 January 2021
Additional Information:
Funding Information:
Funding: This research was funded by the Swiss Office of Energy, Grant No. SI501568-01, the European Research Council under the European Union’s H2020 program/ERC Grant Agreement No. 679425 and the Royal Academy of Engineering under the Engineering for Development Research Fellowship scheme, Grant No. RF\201819\18\86.
Funding Information:
This research was funded by the Swiss Office of Energy, Grant No. SI501568-01, the European Research Council under the European Union?s H2020 program/ERC Grant Agreement No. 679425 and the Royal Academy of Engineering under the Engineering for Development Research Fellowship scheme, Grant No. RF\201819\18\86.
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords:
Gallium nitride, Magnetic-free converters, Module-level converters, Parallel architecture, Partial shading, Photovoltaic systems, Switched capacitor converters
Identifiers
Local EPrints ID: 449658
URI: http://eprints.soton.ac.uk/id/eprint/449658
ISSN: 1996-1073
PURE UUID: 9b7c1797-5c2b-4825-83ca-c662bb2bad32
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Date deposited: 10 Jun 2021 16:31
Last modified: 18 Mar 2024 04:00
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Contributors
Author:
Georgios Kampitsis
Author:
Efstratios Batzelis
Author:
Remco van Erp
Author:
Elison Matioli
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