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Nahalparvari, MehrdadORCID iD iconorcid.org/0000-0002-1136-581x
Publikationer (10 of 30) Visa alla publikationer
Norrga, S., Jahn, I., Agbemuko, A., Li, G., Alvarez, R., Li, X., . . . Ziad El-Khatib, W. (2025). Interoperability in HVDC systems based on partially open software.
Öppna denna publikation i ny flik eller fönster >>Interoperability in HVDC systems based on partially open software
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2025 (Engelska)Rapport (Refereegranskat)
Abstract [en]

Interoperability in HVDC systems could be supported with open upper-level control and protection (C&P) software, while hardware-near C&P functions stay black-boxed and proprietary. Methodologies like model-based systems engineering and graph theory can assist in defining the boundary between open and closed software. Most likely, partially open C&P software in HVDC is not hindered by legislation, but has to be addressed in contractual agreements. Also, a new responsibility matrix for testing is proposed.

Serie
CIGRE Technical Brochure ; 961
Nyckelord
HVDC, HVDC grids, HVDC systems, Open-Source, Open Source, Multivendor, Multi-vendor, Interoperability, C&P, Control and Protection, Blackbox, Black-box, Blackboxed, Black-boxed, Partially open software, Open software
Nationell ämneskategori
Elkraftsystem och -komponenter
Identifikatorer
urn:nbn:se:kth:diva-363642 (URN)
Anmärkning

QC 20250522

Tillgänglig från: 2025-05-20 Skapad: 2025-05-20 Senast uppdaterad: 2025-05-22Bibliografiskt granskad
Arevalo-Soler, J., Nahalparvari, M., Grob, D., Prieto-Araujo, E., Norrga, S. & Gomis-Bellmunt, O. (2025). Small-Signal Stability and Hardware Validation of Dual-Port Grid-Forming Interconnecting Power Converters in Hybrid AC/DC Grids. IEEE Journal of Emerging and Selected Topics in Power Electronics, 13(1), 809-826
Öppna denna publikation i ny flik eller fönster >>Small-Signal Stability and Hardware Validation of Dual-Port Grid-Forming Interconnecting Power Converters in Hybrid AC/DC Grids
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2025 (Engelska)Ingår i: IEEE Journal of Emerging and Selected Topics in Power Electronics, ISSN 2168-6777, E-ISSN 2168-6785, Vol. 13, nr 1, s. 809-826Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Interconnecting power converters (IPCs) are the main elements enabling the interconnection of multiple high-voltage alternating current (HVac) and high-voltage direct current (HVdc) subgrids. To ensure stable operation of the resulting hybrid ac/dc systems, grid-following (GFL) and grid-forming (GFM) controls need to be carefully assigned to individual IPC terminals when using common IPC controls. In contrast, dual-port GFM control imposes a stable voltage on the ac and dc terminals and can be deployed on all IPCs regardless of the network configuration. In this work, we use hybrid ac/dc admittance models, eigenvalue sensitivities, and case studies to analyze and quantify the underlying properties of ac-GFM control, ac-GFL, and dual-port GFM control. Compared to common ac-GFM and ac-GFL controls, dual-port GFM control: 1) renders IPCs dissipative over a much wider range of frequencies and operating points; 2) significantly reduces the sensitivity of IPC small-signal dynamics to operating point changes; and 3) exhibits an improved dynamic response to severe contingencies. Finally, the results are illustrated and validated in an experimental scaled-down point-to-point HVdc system.

Ort, förlag, år, upplaga, sidor
Institute of Electrical and Electronics Engineers (IEEE), 2025
Nyckelord
Grid forming, Voltage control, Hybrid power systems, Grid following, Power system stability, HVDC transmission, Standards, AC/DC, dual port, grid following (GFL), grid forming (GFM), power converters
Nationell ämneskategori
Reglerteknik
Identifikatorer
urn:nbn:se:kth:diva-361287 (URN)10.1109/JESTPE.2024.3454992 (DOI)001432971300001 ()2-s2.0-85203496454 (Scopus ID)
Anmärkning

QC 20250317

Tillgänglig från: 2025-03-17 Skapad: 2025-03-17 Senast uppdaterad: 2025-03-17Bibliografiskt granskad
Asoodar, M., Nahalparvari, M. & Nee, H.-P. (2025). Virtual Flux-Based Modulation for Adaptive Stress Alleviation of Degraded Cells in CHB-Based MMCs. In: : . Paper presented at PCIM Europe, Nuremberg, Germany, 6-8 May 2025.
Öppna denna publikation i ny flik eller fönster >>Virtual Flux-Based Modulation for Adaptive Stress Alleviation of Degraded Cells in CHB-Based MMCs
2025 (Engelska)Konferensbidrag, Poster (med eller utan abstract) (Refereegranskat)
Nationell ämneskategori
Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:kth:diva-358841 (URN)
Konferens
PCIM Europe, Nuremberg, Germany, 6-8 May 2025
Anmärkning

QC 20250513

Tillgänglig från: 2025-01-21 Skapad: 2025-01-21 Senast uppdaterad: 2025-05-13Bibliografiskt granskad
Asoodar, M., Nahalparvari, M., Schneider, S., Shafikhani, I., Ingeström, G. & Nee, H.-P. (2024). A Novel ON-State Resistance Estimation Technique for Online Condition Monitoring of Semiconductor Devices Under Noisy Conditions. IEEE Open Journal of Instrumentation and Measurement, 3, Article ID 3500113.
Öppna denna publikation i ny flik eller fönster >>A Novel ON-State Resistance Estimation Technique for Online Condition Monitoring of Semiconductor Devices Under Noisy Conditions
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2024 (Engelska)Ingår i: IEEE Open Journal of Instrumentation and Measurement, ISSN 2768-7236, Vol. 3, artikel-id 3500113Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

This article presents a novel method for accurate online extraction of semiconductor ON-state resistance in the presence of measurement noise. In this method, the ON-state resistance value is extracted from the measured ON-state voltage of the semiconductors and the measured load current. The extracted ON-state resistance can be used for online condition monitoring of semiconductors. The proposed method is based on the extraction of selective harmonic content. The estimated values are further enhanced through an integral action that increases the signal-to-noise ratio, making the proposed method suitable in the presence of noisy measurements. The efficacy of the proposed method is verified through simulations in the MATLAB/Simulink environment, and experimentally. The estimated ON-state resistance values from the online setup are compared to offline measurements from an industrial curve tracer, where an overall estimation error of less than 1% is observed. The proposed solution maintains its estimation accuracy under variable load conditions and for different temperatures of the device under test.

Ort, förlag, år, upplaga, sidor
Institute of Electrical and Electronics Engineers (IEEE), 2024
Nyckelord
Semiconductor device measurement, Voltage measurement, Electrical resistance measurement, Temperature measurement, Resistance, Current measurement, Estimation, Condition monitoring, health monitoring, online estimation, ON-state resistance, reliability, semiconductor devices, state of health
Nationell ämneskategori
Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:kth:diva-350046 (URN)10.1109/OJIM.2024.3379414 (DOI)001252441500001 ()2-s2.0-85205405560 (Scopus ID)
Anmärkning

QC 20240705

Tillgänglig från: 2024-07-05 Skapad: 2024-07-05 Senast uppdaterad: 2025-01-22Bibliografiskt granskad
Asoodar, M., Nahalparvari, M. & Nee, H.-P. (2024). A Sensorless Active Snubber Circuit for Series Connection of Semiconductor Devices in Modular Multilevel Converters. In: 2024 IEEE 9th Southern Power Electronics Conference (SPEC): . Paper presented at 2024 IEEE 9th Southern Power Electronics Conference (SPEC), Brisbane, QLD, Australia, December 2-5, 2024. Institute of Electrical and Electronics Engineers (IEEE)
Öppna denna publikation i ny flik eller fönster >>A Sensorless Active Snubber Circuit for Series Connection of Semiconductor Devices in Modular Multilevel Converters
2024 (Engelska)Ingår i: 2024 IEEE 9th Southern Power Electronics Conference (SPEC), Institute of Electrical and Electronics Engineers (IEEE) , 2024Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

Commercially available semiconductor devices have a limited range of operating voltages. This operating voltage can be increased through series connection of the devices. In this paper, a novel active snubber circuit (ASC) is proposed that protects series-connected semiconductor devices from overvoltages during operation. The unique advantage of the proposed solution is that it does not use additional sensors or an external controller for voltage protection. That is, each ASC is equipped with sufficient components to protect its respective device. The proposed solution is mainly developed for cascaded H-bridge (CHB) and modular multilevel converters (MMCs) intended for flexible alternating current transmission systems (FACTS) and high-voltage direct current (HVDC) applications, which typically operate at low switching frequencies. Suitable extensions of the proposed design are provided for increased current capability and for possible fault-ride-through functionality. The efficacy of the proposed solution is verified by simulations in the MATLAB/Simulink environment.

Ort, förlag, år, upplaga, sidor
Institute of Electrical and Electronics Engineers (IEEE), 2024
Nyckelord
Active snubber, flexible ac transmission systems, high voltage direct current, modular multilevel converter, series connection
Nationell ämneskategori
Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:kth:diva-358840 (URN)10.1109/SPEC62217.2024.10893142 (DOI)001445813800055 ()2-s2.0-105001121161 (Scopus ID)
Konferens
2024 IEEE 9th Southern Power Electronics Conference (SPEC), Brisbane, QLD, Australia, December 2-5, 2024
Anmärkning

Part of ISBN

979-8-3503-5115-6

QC 20250415

Tillgänglig från: 2025-01-21 Skapad: 2025-01-21 Senast uppdaterad: 2025-05-27Bibliografiskt granskad
Asoodar, M., Nahalparvari, M., Nee, H.-P. & Shafikhani, I. (2024). A Time-Skew Resilient Online Condition Monitoring Technique for Power MOSFETs Based on ON-State Resistance Estimation. In: : . Paper presented at 2024 IEEE 9th Southern Power Electronics Conference (SPEC), Brisbane, QLD, Australia, Dec. 2-5, 2024.
Öppna denna publikation i ny flik eller fönster >>A Time-Skew Resilient Online Condition Monitoring Technique for Power MOSFETs Based on ON-State Resistance Estimation
2024 (Engelska)Konferensbidrag, Muntlig presentation med publicerat abstract (Refereegranskat)
Nationell ämneskategori
Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:kth:diva-358838 (URN)
Konferens
2024 IEEE 9th Southern Power Electronics Conference (SPEC), Brisbane, QLD, Australia, Dec. 2-5, 2024
Anmärkning

QC 20250218

Tillgänglig från: 2025-01-21 Skapad: 2025-01-21 Senast uppdaterad: 2025-02-18Bibliografiskt granskad
Asoodar, M., Nahalparvari, M., Nee, H.-P. & Shafikhani, I. (2024). A Time-Skew Resilient Online Condition Monitoring Technique for Power MOSFETs Based on ON-State Resistance Estimation. In: Proceedings 9th IEEE Southern Power Electronics Conference, SPEC 2024: . Paper presented at 9th IEEE Southern Power Electronics Conference, SPEC 2024, Brisbane, Australia, Dec 2 2024 - Dec 5 2024. Institute of Electrical and Electronics Engineers (IEEE)
Öppna denna publikation i ny flik eller fönster >>A Time-Skew Resilient Online Condition Monitoring Technique for Power MOSFETs Based on ON-State Resistance Estimation
2024 (Engelska)Ingår i: Proceedings 9th IEEE Southern Power Electronics Conference, SPEC 2024, Institute of Electrical and Electronics Engineers (IEEE) , 2024Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

This article presents a unique method of extracting the ON-state resistance of metal-oxide-semiconductor field-effect transistors (MOSFETs) used in power electronic systems. The proposed method uses ON-state voltage measurements of the device-under-test as well as the load current. Contrary to prior-art solutions, the proposed method does not require estimating the device currents, but rather directly uses the load current measurements. This reduces the computational effort for estimation without reducing the estimation accuracy. Moreover, it is shown that unlike time-based estimation techniques such as the recursive least-squares estimation method, the proposed solution does not require ON-state voltage and current measurements to be accurately synchronized. The extracted ON-state resistance can be used for online condition monitoring of semiconductors, as well as for estimating the junction temperature. The efficacy of the proposed method is verified experimentally under constant and variable load conditions. Moreover, the extracted resistance values from the online setup are compared to offline measurements from an industrial curve tracer, where an overall estimation error of less than 1% is observed.

Ort, förlag, år, upplaga, sidor
Institute of Electrical and Electronics Engineers (IEEE), 2024
Nyckelord
Condition monitoring, health monitoring, on-state resistance, online estimation, reliability, semiconductor devices, state of health
Nationell ämneskategori
Annan elektroteknik och elektronik Signalbehandling
Identifikatorer
urn:nbn:se:kth:diva-362226 (URN)10.1109/SPEC62217.2024.10893107 (DOI)001445813800048 ()2-s2.0-105001107560 (Scopus ID)
Konferens
9th IEEE Southern Power Electronics Conference, SPEC 2024, Brisbane, Australia, Dec 2 2024 - Dec 5 2024
Anmärkning

QC 20250414

Tillgänglig från: 2025-04-09 Skapad: 2025-04-09 Senast uppdaterad: 2025-06-12Bibliografiskt granskad
Nahalparvari, M., Asoodar, M., Norrga, S. & Nee, H.-P. (2024). AC-Side Impedance-Based Stability Assessment in Grid-Forming Modular Multilevel Converters. IEEE Access, 12, 23514-23528
Öppna denna publikation i ny flik eller fönster >>AC-Side Impedance-Based Stability Assessment in Grid-Forming Modular Multilevel Converters
2024 (Engelska)Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 12, s. 23514-23528Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Grid-forming converters can emulate the behavior of a synchronous generator through frequency droop control. The stability of grid-forming modular multilevel converters can be studied via the impedance-based stability criterion. This paper presents an ac-side impedance model of a grid-forming modular multilevel converter which includes a complete grid-forming control structure. The impact of different control schemes and parameters on the closed-loop output impedance of the converter is thoroughly analyzed and the learnings have been used in mitigating undesired control interactions with the grid. The results are verified through simulations in time- and frequency-domains along with experiments on a down-scaled laboratory prototype.

Ort, förlag, år, upplaga, sidor
Institute of Electrical and Electronics Engineers (IEEE), 2024
Nyckelord
Control interaction, frequency-domain analysis, grid-forming control, harmonic linearization, impedance modeling, modular multilevel converter (MMC), stability
Nationell ämneskategori
Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:kth:diva-343989 (URN)10.1109/ACCESS.2024.3365053 (DOI)001164026200001 ()2-s2.0-85185546685 (Scopus ID)
Anmärkning

QC 20240301

Tillgänglig från: 2024-02-28 Skapad: 2024-02-28 Senast uppdaterad: 2024-11-19Bibliografiskt granskad
Asoodar, M. & Nahalparvari, M. (2024). An Active Voltage Balancing Technique for Series Connection of Semiconductor Devices in Modular Multilevel Converters. In: 2024 Energy Conversion Congress & Expo Europe (ECCE Europe): . Paper presented at 2024 Energy Conversion Congress & Expo Europe (ECCE Europe). Institute of Electrical and Electronics Engineers (IEEE)
Öppna denna publikation i ny flik eller fönster >>An Active Voltage Balancing Technique for Series Connection of Semiconductor Devices in Modular Multilevel Converters
2024 (Engelska)Ingår i: 2024 Energy Conversion Congress & Expo Europe (ECCE Europe), Institute of Electrical and Electronics Engineers (IEEE) , 2024Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

Series connection of semiconductor devices facilitates the development of higher-voltage submodules in modular multilevel converters (MMCs) using commercially available lower-voltage semiconductor devices. However, if left uncontrolled, series-connected semiconductors may experience unequal voltage sharing after each switching event. This unequal distribution lead to semiconductor damage and system failure. This paper proposes a novel method for the series connection of semiconductor devices. The proposed solution utilizes an active snubber circuit (ASC) and a unique control system that ensure controlled voltage sharing among the semiconductors. The solution is mainly intended for MMCs operating at low switching frequencies. The efficacy of the proposed solution is verified through simulations in the MATLAB/Simulink environment.

Ort, förlag, år, upplaga, sidor
Institute of Electrical and Electronics Engineers (IEEE), 2024
Nationell ämneskategori
Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:kth:diva-358811 (URN)10.1109/ECCEEurope62508.2024.10752059 (DOI)2-s2.0-85211803231 (Scopus ID)
Konferens
2024 Energy Conversion Congress & Expo Europe (ECCE Europe)
Anmärkning

Part of ISBN 979-8-3503-6444-6

QC 20250121

Tillgänglig från: 2025-01-21 Skapad: 2025-01-21 Senast uppdaterad: 2025-02-25Bibliografiskt granskad
Asoodar, M., Nahalparvari, M., Danielsson, C. & Nee, H.-P. (2024). Current-Independent Online Condition Monitoring of DC-Link Capacitors in Cascaded H-bridge and Modular Multilevel Converters. In: : . Paper presented at 2024 IEEE 9th Southern Power Electronics Conference (SPEC), Brisbane, QLD, Australia, Dec. 2-5, 2024.
Öppna denna publikation i ny flik eller fönster >>Current-Independent Online Condition Monitoring of DC-Link Capacitors in Cascaded H-bridge and Modular Multilevel Converters
2024 (Engelska)Konferensbidrag, Muntlig presentation med publicerat abstract (Refereegranskat)
Nationell ämneskategori
Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:kth:diva-358839 (URN)
Konferens
2024 IEEE 9th Southern Power Electronics Conference (SPEC), Brisbane, QLD, Australia, Dec. 2-5, 2024
Anmärkning

QC 20250218

Tillgänglig från: 2025-01-21 Skapad: 2025-01-21 Senast uppdaterad: 2025-02-18Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-1136-581x

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