A New Transformer-Less Single-Phase Photovoltaic Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic Systems
Photovoltaic (PV) energy systems have found diverse applications in fulfilling the increasing energy demand worldwide. Transformer-less PV inverters convert the DC energy from PV systems to AC energy and deliver it to the grid through a non-isolated connection. This paper proposes a new transformer-...
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MDPI AG
2022-11-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/15/22/8398 |
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| author | Mohua Biswas Shuvra Prokash Biswas Md. Rabiul Islam Md. Ashib Rahman Kashem M. Muttaqi S. M. Muyeen |
| author_facet | Mohua Biswas Shuvra Prokash Biswas Md. Rabiul Islam Md. Ashib Rahman Kashem M. Muttaqi S. M. Muyeen |
| author_sort | Mohua Biswas |
| collection | DOAJ |
| description | Photovoltaic (PV) energy systems have found diverse applications in fulfilling the increasing energy demand worldwide. Transformer-less PV inverters convert the DC energy from PV systems to AC energy and deliver it to the grid through a non-isolated connection. This paper proposes a new transformer-less grid-connected PV inverter. A closed-loop control scheme is presented for the proposed transformer-less inverter to connect it with the power grid. The proposed transformer-less inverter reduces extra leakage current and holds the common-mode voltage at a constant point. To eliminate extra leakage current, as well as achieve constant common-mode voltage, a midpoint clamping method is utilized to operate the inverter. The proposed transformer-less inverter is formed of seven insulated gate bipolar transistors (IGBTs) employing a unipolar sinusoidal pulse width modulation (SPWM) technique for switching purposes. An LCL filter is employed to reshape the two-level inverter output voltage and current to obtain closer sinusoidal waveforms. The output voltage and current total harmonic distortion (THD) of the proposed transformer-less inverter were found to be 1.25% and 0.94%, respectively, in the grid-connected mode. The leakage current elimination mechanism with the proposed transformer-less inverter is deeply analyzed in this paper. The performances of the proposed transformer-less inverter were evaluated with MATLAB/Simulink simulation and validated in a laboratory scale experiment. |
| first_indexed | 2024-03-09T18:22:43Z |
| format | Article |
| id | doaj.art-ae51da0d587b4770aa4f8c3bfc239e02 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-09T18:22:43Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-ae51da0d587b4770aa4f8c3bfc239e022023-11-24T08:12:28ZengMDPI AGEnergies1996-10732022-11-011522839810.3390/en15228398A New Transformer-Less Single-Phase Photovoltaic Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic SystemsMohua Biswas0Shuvra Prokash Biswas1Md. Rabiul Islam2Md. Ashib Rahman3Kashem M. Muttaqi4S. M. Muyeen5Department of Electronics & Telecommunication Engineering, Rajshahi University of Engineering & Technology, Rajshahi 6204, BangladeshDepartment of Electronics & Telecommunication Engineering, Rajshahi University of Engineering & Technology, Rajshahi 6204, BangladeshSchool of Electrical, Computer and Telecommunications Engineering, University of Wollongong, Wollongong, NSW 2522, AustraliaSchool of Electrical, Computer and Telecommunications Engineering, University of Wollongong, Wollongong, NSW 2522, AustraliaSchool of Electrical, Computer and Telecommunications Engineering, University of Wollongong, Wollongong, NSW 2522, AustraliaDepartment of Electrical Engineering, Qatar University, Doha 2713, QatarPhotovoltaic (PV) energy systems have found diverse applications in fulfilling the increasing energy demand worldwide. Transformer-less PV inverters convert the DC energy from PV systems to AC energy and deliver it to the grid through a non-isolated connection. This paper proposes a new transformer-less grid-connected PV inverter. A closed-loop control scheme is presented for the proposed transformer-less inverter to connect it with the power grid. The proposed transformer-less inverter reduces extra leakage current and holds the common-mode voltage at a constant point. To eliminate extra leakage current, as well as achieve constant common-mode voltage, a midpoint clamping method is utilized to operate the inverter. The proposed transformer-less inverter is formed of seven insulated gate bipolar transistors (IGBTs) employing a unipolar sinusoidal pulse width modulation (SPWM) technique for switching purposes. An LCL filter is employed to reshape the two-level inverter output voltage and current to obtain closer sinusoidal waveforms. The output voltage and current total harmonic distortion (THD) of the proposed transformer-less inverter were found to be 1.25% and 0.94%, respectively, in the grid-connected mode. The leakage current elimination mechanism with the proposed transformer-less inverter is deeply analyzed in this paper. The performances of the proposed transformer-less inverter were evaluated with MATLAB/Simulink simulation and validated in a laboratory scale experiment.https://www.mdpi.com/1996-1073/15/22/8398photovoltaic energytransformer-less invertergrid-connected inverterleakage currentcommon-mode voltageunipolar sinusoidal pulse width modulation |
| spellingShingle | Mohua Biswas Shuvra Prokash Biswas Md. Rabiul Islam Md. Ashib Rahman Kashem M. Muttaqi S. M. Muyeen A New Transformer-Less Single-Phase Photovoltaic Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic Systems Energies photovoltaic energy transformer-less inverter grid-connected inverter leakage current common-mode voltage unipolar sinusoidal pulse width modulation |
| title | A New Transformer-Less Single-Phase Photovoltaic Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic Systems |
| title_full | A New Transformer-Less Single-Phase Photovoltaic Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic Systems |
| title_fullStr | A New Transformer-Less Single-Phase Photovoltaic Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic Systems |
| title_full_unstemmed | A New Transformer-Less Single-Phase Photovoltaic Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic Systems |
| title_short | A New Transformer-Less Single-Phase Photovoltaic Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic Systems |
| title_sort | new transformer less single phase photovoltaic inverter to improve the performance of grid connected solar photovoltaic systems |
| topic | photovoltaic energy transformer-less inverter grid-connected inverter leakage current common-mode voltage unipolar sinusoidal pulse width modulation |
| url | https://www.mdpi.com/1996-1073/15/22/8398 |
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