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Publications (10 of 259) Show all publications
Bakas, P., Okazaki, Y., Ilves, K., Norrga, S., Harnefors, L. & Nee, H.-P. (2019). Design considerations and comparison of hybrid line-commutated and cascaded full-bridge converters with reactive-power compensation and active filtering capabilities. In: : . Paper presented at 2019 21st European Conference on Power Electronics and Applications (EPE'19 ECCE Europe).
Open this publication in new window or tab >>Design considerations and comparison of hybrid line-commutated and cascaded full-bridge converters with reactive-power compensation and active filtering capabilities
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2019 (English)Conference paper, Published paper (Other academic)
Abstract [en]

This paper compares two hybrid topologies that combine the line-commutated converter (LCC) with cascaded full-bridge (FB) converters. The latter are utilized for compensating the reactive power and filtering the current harmonics of the LCC. The method that was developed for dimensioning these hybrid topologies is presented in detail. This method is utilized for calculating the arm voltage and current waveforms, which are used to estimate other important quantities, such as conduction losses and energy variations. Finally, the studied converters are compared in terms of voltage/current ratings, semiconductor requirements, conduction losses, and energy variations.

Keywords
Converter circuit, HVDC, Multilevel converters, Thyristor.
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-262671 (URN)978-9-0758-1530-6 (ISBN)
Conference
2019 21st European Conference on Power Electronics and Applications (EPE'19 ECCE Europe)
Funder
SweGRIDS - Swedish Centre for Smart Grids and Energy Storage, SP8
Note

QC 20191018

Available from: 2019-10-17 Created: 2019-10-17 Last updated: 2019-10-18Bibliographically approved
Bakas, P., Okazaki, Y., Ilves, K., Norrga, S., Harnefors, L. & Nee, H.-P. (2019). Design considerations and comparison of hybrid line-commutated and cascaded full-bridge converters with reactive-power compensation and active filtering capabilities. In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe: . Paper presented at 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, 3-5 September 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Design considerations and comparison of hybrid line-commutated and cascaded full-bridge converters with reactive-power compensation and active filtering capabilities
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2019 (English)In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper, Published paper (Refereed)
Abstract [en]

This paper compares two hybrid topologies that combine the line-commutated converter (LCC) with cascaded full-bridge (FB) converters. The latter are utilized for compensating the reactive power and filtering the current harmonics of the LCC. The method that was developed for dimensioning these hybrid topologies is presented in detail. This method is utilized for calculating the arm voltage and current waveforms, which are used to estimate other important quantities, such as conduction losses and energy variations. Finally, the studied converters are compared in terms of voltage/current ratings, semiconductor requirements, conduction losses, and energy variations.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
Converter circuit, HVDC, Multilevel converters, Thyristor, Active filters, Power electronics, Reactive power, Thyristors, Topology, Converter circuits, Design considerations, Full bridge converters, Line commutated converter (LCC), Multilevel converter, Reactive power compensation, Voltage and current waveforms, Power converters
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-268052 (URN)10.23919/EPE.2019.8915146 (DOI)2-s2.0-85076669919 (Scopus ID)9789075815313 (ISBN)
Conference
21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, 3-5 September 2019
Note

QC 20200218

Available from: 2020-02-18 Created: 2020-02-18 Last updated: 2020-02-18Bibliographically approved
Bakas, P., Ilves, K., Norrga, S., Harnefors, L. & Nee, H.-P. (2019). Hybrid alternate-common-arm converter with director thyristors - Impact of commutation time on the active-power capability. In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe: . Paper presented at 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, 3-5 September 2019, Genova, Italy. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Hybrid alternate-common-arm converter with director thyristors - Impact of commutation time on the active-power capability
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2019 (English)In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper, Published paper (Refereed)
Abstract [en]

This paper investigates the impact of the thyristor commutation time on the peak currents and the active-power capability of the hybrid alternate-common-arm converter (HACC). This converter employs director thyristors for the alternate connection of a common arm in parallel to the main arms. The parallel connection enables current sharing among the arms, which allows the HACC to transfer higher output power without increasing the peak arm current. It is shown that the active-power capability of the HACC is doubled for a certain current-sharing factor, which, however, is altered by the thyristor commutation time. Therefore, the impact of the commutation time on the active-power capability of the HACC is investigated theoretically. Finally, this analysis is verified by simulation results.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
Converter circuit, HVDC, Multilevel converters, Thyristor, Electric connectors, Power converters, Commutation time, Converter circuits, Current-sharing, Multilevel converter, Output power, Parallel connections, Peak currents, Thyristors
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-268051 (URN)10.23919/EPE.2019.8915473 (DOI)2-s2.0-85076682012 (Scopus ID)978-9-0758-1531-3 (ISBN)978-1-7281-2361-5 (ISBN)
Conference
21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, 3-5 September 2019, Genova, Italy
Note

QC 20200217

Available from: 2020-02-17 Created: 2020-02-17 Last updated: 2020-02-17Bibliographically approved
Bakas, P., Ilves, K., Norrga, S., Harnefors, L. & Nee, H.-P. (2019). Hybrid alternate-common-arm converter with director thyristors: Impact of commutation time on the active-power capability. In: Proc. 2019 21st European Conference on Power Electronics and Applications (EPE'19 ECCE Europe), IEEE and EPE Association, Genova, Italy, Sep. 2-6, 2019: . Paper presented at 2019 21st European Conference on Power Electronics and Applications (EPE'19 ECCE Europe), Genova, Italy, Sep. 2-6, 2019. Genova, Italy: IEEE and EPE Association
Open this publication in new window or tab >>Hybrid alternate-common-arm converter with director thyristors: Impact of commutation time on the active-power capability
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2019 (English)In: Proc. 2019 21st European Conference on Power Electronics and Applications (EPE'19 ECCE Europe), IEEE and EPE Association, Genova, Italy, Sep. 2-6, 2019, Genova, Italy: IEEE and EPE Association , 2019Conference paper, Published paper (Other academic)
Abstract [en]

This paper investigates the impact of the thyristor commutation time on the peak currents and the active power capability of the hybrid alternate-common-arm converter (HACC). This converter employs director thyristors for the alternate connection of a common arm in parallel to the main arms. The parallel connection enables current sharing among the arms, which allows the HACC to transfer higher output power without increasing the peak arm current. It is shown that the active-power capability of the HACC is doubled for a certain current-sharing factor, which, however, is altered by the thyristor commutation time. Therefore, the impact of the commutation time on the active-power capability of the HACC is investigated theoretically. Finally, this analysis is verified by simulation results.

Place, publisher, year, edition, pages
Genova, Italy: IEEE and EPE Association, 2019
Keywords
Converter circuit, HVDC, Multilevel converters, Thyristor.
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-262670 (URN)978-9-0758-1530-6 (ISBN)
Conference
2019 21st European Conference on Power Electronics and Applications (EPE'19 ECCE Europe), Genova, Italy, Sep. 2-6, 2019
Funder
SweGRIDS - Swedish Centre for Smart Grids and Energy Storage, SP8
Note

QC 20191018

Available from: 2019-10-17 Created: 2019-10-17 Last updated: 2019-10-21Bibliographically approved
Sadik, D.-P., Ranstad, P. & Nee, H.-P. (2019). Impact of blanking time on switching losses in a SiC MOSFET-based converter using capacitive snubbers. In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe: . Paper presented at 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe; Genova; Italy; 3 September 2019 through 5 September 2019. Institute of Electrical and Electronics Engineers (IEEE), Article ID 8915564.
Open this publication in new window or tab >>Impact of blanking time on switching losses in a SiC MOSFET-based converter using capacitive snubbers
2019 (English)In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, Institute of Electrical and Electronics Engineers (IEEE), 2019, article id 8915564Conference paper, Published paper (Refereed)
Abstract [en]

Wide Bandgap power semiconductors such as SiC MOSFETs, have enabled compact and highly efficient power converters operated at higher frequencies. In converters using SiC MOSFETs and capacitive snubbers, the blanking times may have a significant impact on switching losses. The power losses induced by unnecessary long blanking times have been quantified experimentally. It was found that, at 100 kHz, an adaptive blanking time can reduce the losses by more than 20 %. As those losses are directly proportional to the switching frequency, an adaptive blanking time is essential when designing for high operation frequencies. Doing so, higher operation frequencies are possible while maintaining a high efficiency.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-266875 (URN)10.23919/EPE.2019.8915564 (DOI)2-s2.0-85076714022 (Scopus ID)9789075815313 (ISBN)
Conference
21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe; Genova; Italy; 3 September 2019 through 5 September 2019
Note

QC 20200124

Available from: 2020-01-24 Created: 2020-01-24 Last updated: 2020-01-24Bibliographically approved
Heinig, S., Jacobs, K., Ilves, K., Bessegato, L., Bakas, P., Norrga, S. & Nee, H.-P. (2019). Implications of Capacitor Voltage Imbalance on the Operation of the Semi-Full-Bridge Submodule. IEEE transactions on power electronics, 34(10), 9520-9535, Article ID 8598807.
Open this publication in new window or tab >>Implications of Capacitor Voltage Imbalance on the Operation of the Semi-Full-Bridge Submodule
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2019 (English)In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 34, no 10, p. 9520-9535, article id 8598807Article in journal (Refereed) Published
Abstract [en]

Future meshed high-voltage direct current grids require modular multilevel converters with extended functionality. One of the most interesting new submodule topologies is the semi-full-bridge because it enables efficient handling of DC-side short circuits while having reduced power losses compared to an implementation with full-bridge submodules. However, the semi-full-bridge submodule requires the parallel connection of capacitors during normal operation which can cause a high redistribution current in case the voltages of the two submodule capacitors are not equal. The maximum voltage difference and resulting redistribution current have been studied analytically, by means of simulations and in a full-scale standalone submodule laboratory setup. The most critical parameter is the capacitance mismatch between the two capacitors. The experimental results from the full-scale prototype show that the redistribution current peaks at 500A if the voltage difference is 10V before paralleling and increases to 2500A if the difference is 40V. However, neglecting very unlikely cases, the maximum voltage difference predicted by simulations is not higher than 20-30V for the considered case. Among other measures, a balancing controller is proposed which reduces the voltage difference safely if a certain maximum value is surpassed. The operating principle of the controller is described in detail and verified experimentally on a down-scaled submodule within a modular multilevel converter prototype. It can be concluded that excessively high redistribution currents can be prevented. Consequently, they are no obstacle for using the semi-full-bridge submodule in future HVDC converters.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
Keywords
AC-DC power conversion, HVDC converters, HVDC transmission, Power transmission, Fault tolerance, Power system faults
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-240824 (URN)10.1109/TPEL.2018.2890622 (DOI)000474581900016 ()2-s2.0-85068640873 (Scopus ID)
Funder
SweGRIDS - Swedish Centre for Smart Grids and Energy Storage, CPC4
Note

QC 20190107

Available from: 2019-01-03 Created: 2019-01-03 Last updated: 2019-07-31Bibliographically approved
Jacobs, K., Heinig, S., Ciftci, B., Norrga, S. & Nee, H.-P. (2019). Low Loss Submodule Cluster for ModularMultilevel Converters Suitable for Implementationwith SiC MOSFETs. In: Proceedings IEEE Energy Conversion Congress and Exposition 2019: . Paper presented at IEEE Energy Conversion Congress and Exposition - IEEE-ECCE 2019, Baltimore, MD, Sept. 29 – Oct. 3, 2019. IEEE
Open this publication in new window or tab >>Low Loss Submodule Cluster for ModularMultilevel Converters Suitable for Implementationwith SiC MOSFETs
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2019 (English)In: Proceedings IEEE Energy Conversion Congress and Exposition 2019, IEEE, 2019Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, a novel submodule cluster topologyfor modular multilevel converters is proposed. The cluster iscomposed of an arbitrary amount of submodule segments. Dependingon the amount of capacitors in the cluster, the converterconduction losses can be reduced significantly. The topologyenables electronic protection against explosion, thus, reducingthe requirements for submodule bypass equipment. Implicationsfor the converter operation and functionality are investigated anda wireless control scheme is proposed.

Place, publisher, year, edition, pages
IEEE, 2019
Series
IEEE Energy Conversion Congress and Exposition, E-ISSN 2329-3748
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-266791 (URN)10.1109/ECCE.2019.8913183 (DOI)2-s2.0-85076778956 (Scopus ID)978-1-7281-0395-2 (ISBN)978-1-7281-0396-9 (ISBN)
Conference
IEEE Energy Conversion Congress and Exposition - IEEE-ECCE 2019, Baltimore, MD, Sept. 29 – Oct. 3, 2019
Note

QC 20200122

Available from: 2020-01-22 Created: 2020-01-22 Last updated: 2020-01-22Bibliographically approved
Ciftci, B., Gross, J., Norrga, S. & Nee, H.-P. (2019). Simple Distributed Control for Modular Multilevel Converters. In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe: . Paper presented at 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe; Genova, Italy; SEP 03-05, 2019. Brussels: European Power Electronics and Drives Association, Article ID 8915488.
Open this publication in new window or tab >>Simple Distributed Control for Modular Multilevel Converters
2019 (English)In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, Brussels: European Power Electronics and Drives Association, 2019, , p. 10article id 8915488Conference paper, Published paper (Refereed)
Abstract [en]

The central control of MMC becomes demanding in computation power and communication bandwidth as the number of submodules increase. Distributed control methods can overcome these bottlenecks. In this paper, a simple distributed control method together with synchronization of modulation carriers in the submodules is presented. The proposal is implemented on a lab-scale MMC with asynchronous-serial communication on a star network between the central and local controllers. It is shown that the proposed control method works satisfactorily in the steady state. The method can be applied as is to MMCs with any number of submodules per arm.

Place, publisher, year, edition, pages
Brussels: European Power Electronics and Drives Association, 2019. p. 10
Keywords
Multilevel converters, Digital control, Field Programmable Gate Array (FPGA), Communication for Power Electronics
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-257886 (URN)10.23919/EPE.2019.8915488 (DOI)000515073403063 ()2-s2.0-85076681154 (Scopus ID)978-9-0758-1530-6 (ISBN)
Conference
21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe; Genova, Italy; SEP 03-05, 2019
Note

QC 20190916

Available from: 2019-09-07 Created: 2019-09-07 Last updated: 2020-03-24Bibliographically approved
Zhang, H., Wang, X., Harnefors, L., Gong, H., Hasler, J.-P. -. & Nee, H.-P. (2019). SISO Transfer Functions for Stability Analysis of Grid-Connected Voltage-Source Converters. IEEE transactions on industry applications, 55(3), 2931-2941, Article ID 8640057.
Open this publication in new window or tab >>SISO Transfer Functions for Stability Analysis of Grid-Connected Voltage-Source Converters
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2019 (English)In: IEEE transactions on industry applications, ISSN 0093-9994, E-ISSN 1939-9367, Vol. 55, no 3, p. 2931-2941, article id 8640057Article in journal (Refereed) Published
Abstract [en]

Converter-grid interaction is of great interest in a weak-grid condition. This paper presents a single-input-single-output (SISO) open-loop transfer function for the stability analysis of grid-connected voltage-source converters. Differing from the conventional input impedance method and the eigenvalue analysis, an alternative multi-input-multi-output closed-loop system is developed in the paper and it eventually yields an SISO open-loop transfer function. This enables the application of a single Nyquist curve for analyzing the overall system stability. The model is validated against time-domain simulations as well as experimental results showing excellent accuracy for predicting the system stability.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
Multi-input-multi-output (MIMO), Nyquist stability criterion, single-input-single-output (SISO), voltage-source converter (VSC), weak grid, Closed loop systems, Eigenvalues and eigenfunctions, MIMO systems, Stability criteria, System stability, Telecommunication repeaters, Time domain analysis, Multi input multi output, Single input single output, Voltage source converters, Transfer functions
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-252523 (URN)10.1109/TIA.2019.2898978 (DOI)000466033700073 ()2-s2.0-85064988163 (Scopus ID)
Note

QC 20190613

Available from: 2019-06-13 Created: 2019-06-13 Last updated: 2019-06-13Bibliographically approved
Lindahl, M., Velander, E., Blomberg, A. & Nee, H.-P. (2019). Threshold for induction motor terminal transient peak voltage with fast switching inverters. In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe: . Paper presented at 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, 3 September 2019 through 5 September 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Threshold for induction motor terminal transient peak voltage with fast switching inverters
2019 (English)In: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper, Published paper (Refereed)
Abstract [en]

Concerns have been raised that motor voltages might be very high if the fast switching characteristics of silicon carbide (SiC) are to be utilized. For this reason, the magnitude of the terminal voltage of an induction motor is investigated when fed from a fast switching SiC inverter through a long cable. It is found that the main insulation demand for the SiC case is only increased by 5 % compared to the silicon insulated-gate bipolar transistor (IGBT) case. This indicates that additional filters may not be necessary in applications with long cables where silicon IGBTs are replaced by fast switching SiC power semiconductors.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
Adjustable speed drive, Asynchronous motor, Induction motor, Industrial application, Insulation, Rail vehicle, Silicon Carbide (SiC, Switching speed, Traction application, Cables, Electric inverters, Industrial applications, Insulated gate bipolar transistors (IGBT), Semiconducting silicon compounds, Silicon carbide, Switching, Transients, Variable speed drives, Wide band gap semiconductors, Additional filters, Adjustable speed drives, Power semiconductors, Rail vehicles, Silicon carbides (SiC), Terminal voltages, Traction applications, Induction motors
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-268050 (URN)10.23919/EPE.2019.8914765 (DOI)2-s2.0-85076711545 (Scopus ID)9789075815313 (ISBN)
Conference
21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe, 3 September 2019 through 5 September 2019
Note

QC 20200316

Available from: 2020-03-16 Created: 2020-03-16 Last updated: 2020-03-16Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1755-1365

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