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Publications (10 of 254) 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., 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
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
Ciftci, B., Gross, J., Norrga, S. & Nee, H.-P. (2019). Simple Distributed Control for Modular Multilevel Converters. In: : . Paper presented at 21st European Conference on Power Electronics and Applications. Brussels: European Power Electronics and Drives Association
Open this publication in new window or tab >>Simple Distributed Control for Modular Multilevel Converters
2019 (English)Conference 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)978-9-0758-1530-6 (ISBN)
Conference
21st European Conference on Power Electronics and Applications
Note

QC 20190916

Available from: 2019-09-07 Created: 2019-09-07 Last updated: 2019-09-16Bibliographically 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
Nikouie, M., Zhang, H., Wallmark, O. & Nee, H.-P. (2018). A highly integrated electric drive system for tomorrow's EVs and HEVs. In: Proceedings - 2017 IEEE Southern Power Electronics Conference, SPEC 2017: . Paper presented at 2017 IEEE Southern Power Electronics Conference, SPEC 2017, Hotel Enjoy Puerto VarasPuerto Varas, Chile, 4 December 2017 through 7 December 2017 (pp. 1-5). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>A highly integrated electric drive system for tomorrow's EVs and HEVs
2018 (English)In: Proceedings - 2017 IEEE Southern Power Electronics Conference, SPEC 2017, Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1-5Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents an ultra-compact integrated electric drive prototype. The prototype illustrates the integration of a fractional slot concentrated winding (FSCW) electric motor, a stacked polyphase bridges (SPB) converter, the control boards, and the water cooling plates into a common housing. This integrated prototype offers a high potential of compactness and cost reduction for electric and hybrid electric vehicles.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-238250 (URN)10.1109/SPEC.2017.8333555 (DOI)2-s2.0-85049217902 (Scopus ID)9781509064250 (ISBN)
Conference
2017 IEEE Southern Power Electronics Conference, SPEC 2017, Hotel Enjoy Puerto VarasPuerto Varas, Chile, 4 December 2017 through 7 December 2017
Note

QC 20181120

Available from: 2018-11-20 Created: 2018-11-20 Last updated: 2019-04-11Bibliographically approved
Ciftci, B., Gross, J., Norrga, S., Kildehöj, L. & Nee, H.-P. (2018). A Proposal for Wireless Control of Submodules in Modular Multilevel Converters. In: : . Paper presented at 20th European Conference on Power Electronics and Applications.
Open this publication in new window or tab >>A Proposal for Wireless Control of Submodules in Modular Multilevel Converters
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2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

The modular multilevel converter is one of the most preferred converters for high-power conversion applications. Wireless control of the submodules can contribute to its evolution by lowering the material and labor costs of cabling and by increasing the availability of the converter. However, wireless control leads to many challenges for the control and modulation of the converter as well as for proper low-latency high-reliability communication. This paper investigates the tolerable asynchronism between phase-shifted carriers used in modulation from a wireless control point of view and proposes a control method along with communication protocol for wireless control. The functionality of the proposed method is validated by computer simulations in steady state.

Keywords
Modular multilevel converter, Wireless control
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-239736 (URN)000450299300223 ()2-s2.0-85057065852 (Scopus ID)9789075815290 (ISBN)
Conference
20th European Conference on Power Electronics and Applications
Note

QC 20181203

Available from: 2018-12-02 Created: 2018-12-02 Last updated: 2018-12-10Bibliographically approved
Velander, E., Kruse, L. (., Wiik, T. (., Wiberg, A., Colmenares, J. & Nee, H.-P. (2018). An IGBT Turn-ON Concept Offering Low Losses Under Motor Drive dv/dt Constraints Based on Diode Current Adaption. IEEE transactions on power electronics, 33(2), 1143-1153
Open this publication in new window or tab >>An IGBT Turn-ON Concept Offering Low Losses Under Motor Drive dv/dt Constraints Based on Diode Current Adaption
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2018 (English)In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 33, no 2, p. 1143-1153Article in journal (Refereed) Published
Abstract [en]

In this paper, a new low-loss turn-ON concept for the silicon insulated-gate bipolar transistor (Si-IGBT) in combination with silicon p-i-n diode is presented. The concept is tailored for two-level motor converters in the 100 kW to 1 MW range under the constraint that the output voltages slopes are limited in order to protect the motor windings. Moreover, analyses of the IGBT turn-ON and diode reverse recovery voltage slopes are presented concluding that the diode reverse recovery is the worst case. The concept includes a low-cost measurement of the free-wheeling diode current and temperature by the gate driver without necessity of acquiring this information from the converter control board. By using this concept, the output dv/dt at the diode turn-OFF can be kept approximately constant regardless of the commutated current and junction temperature. Hence, the switching losses could be decreased for the currents and temperatures where the voltage slopes are lower when using a conventional gate driver optimized for the worst case. Moreover, results are shown for one such power semiconductor, showing a total switching loss reduction of up to 28% in comparison with a gate driver without current and temperature measurement. Finally, this concept is particularly suitable for high power semiconductor modules in half-bridge configuration which are recently proposed by several suppliers.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
motor drives, insulated gate bipolar transistors, power semiconductor devices
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-217925 (URN)10.1109/TPEL.2017.2688474 (DOI)000414414600025 ()2-s2.0-85034081872 (Scopus ID)
Note

QC 20171121

Available from: 2017-11-21 Created: 2017-11-21 Last updated: 2017-11-21Bibliographically approved
Velander, E., Bohlin, G., Sandberg, A., Wiik, T., Botling, F., Lindahl, M., . . . Nee, H.-P. (2018). An Ultralow Loss Inductorless dv/dt Filter Concept for Medium-Power Voltage Source Motor Drive Converters With SiC Devices. IEEE transactions on power electronics, 33(7), 6072-6081
Open this publication in new window or tab >>An Ultralow Loss Inductorless dv/dt Filter Concept for Medium-Power Voltage Source Motor Drive Converters With SiC Devices
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2018 (English)In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 33, no 7, p. 6072-6081Article in journal (Refereed) Published
Abstract [en]

In this paper, a novel dv/dt filter is presented targeted for 100-kW to 1-MW voltage source converters using silicon carbide (SiC) power devices. This concept uses the stray inductance between the power device and the converter output as a filter component in combination with an additional small RC-link. Hence, a lossy, bulky, and costly filter inductor is avoided and the resulting output dv/dt is limited to 5-10 kV/mu s independent of the output current and switching speed of the SiC devices. As a consequence, loads with dv/dt constraints, e.g., motor drives can be fed from SiC devices enabling full utilization of their high switching speed. Moreover, a filter-model is proposed for the selection of filter component values for a certain dv/dt requirement. Finally, results are shown using a 300-A 1700-V SiC metal-oxide-semiconductor field-effect transistor (MOSFET). These results show that the converter output dv/dt can be limited to 7.5 kV/mu s even though values up to 47 kV/mu s weremeasured across the SiC MOSFET module. Hence, the total switching losses, including the filter losses, are verified to be three times lower compared to when the MOSFET dv/dt was slowed down by adjusting the gate driver.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
AC motor drives, dv/dt control methods, electromagnetic interference (EMI), filters, power semiconductor devices, SiC MOSFET
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-226180 (URN)10.1109/TPEL.2017.2739839 (DOI)000428645100047 ()2-s2.0-85028466153 (Scopus ID)
Note

QC 20180516

Available from: 2018-05-16 Created: 2018-05-16 Last updated: 2019-09-10Bibliographically approved
Jacobs, K., Nee, H.-P. & Norrga, S. (2018). Dissipation Loop for Shoot-Through Faults in HVDC Converter Cells. In: 2018 INTERNATIONAL POWER ELECTRONICS CONFERENCE (IPEC-NIIGATA 2018 -ECCE ASIA): . Paper presented at 8th International Power Electronics Conference (IPEC-Niigata ECCE Asia) Location: Niigata, JAPAN (pp. 3292-3298). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Dissipation Loop for Shoot-Through Faults in HVDC Converter Cells
2018 (English)In: 2018 INTERNATIONAL POWER ELECTRONICS CONFERENCE (IPEC-NIIGATA 2018 -ECCE ASIA), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 3292-3298Conference paper, Published paper (Refereed)
Abstract [en]

Converter cells for HVDC applications store large amounts of energy. This energy might be dissipated in a very short time in case of a shoot-through fault. Measures to avoid shoot-through or handle the extreme currents during a fault and prevent damage from neighboring components are essential to ensure a continued operation of the converter. With future high-voltage silicon carbide semiconductors, cell voltages can be increased leading to higher stored energy per cell. In cells with thyristor-based semiconductors, e.g. IGCTs, a di/dt reactor may have to be employed. This paper presents a method to handle the dissipated energy during shoot-through which makes use of the inherently needed di/dt reactor. The majority of the stored energy in the cell can be dissipated in a dedicated discharge loop formed by the reactor and an antiparallel bypass thyristor. After diverting the fault current into the dissipation loop, there is no current through any other component of the cell.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Series
International Conference on Power Electronics, ISSN 2150-6078
National Category
Energy Systems
Research subject
Electrical Engineering; Energy Technology
Identifiers
urn:nbn:se:kth:diva-239555 (URN)10.23919/IPEC.2018.8507546 (DOI)000449328903038 ()2-s2.0-85057320911 (Scopus ID)978-4-88686-405-5 (ISBN)
Conference
8th International Power Electronics Conference (IPEC-Niigata ECCE Asia) Location: Niigata, JAPAN
Funder
SweGRIDS - Swedish Centre for Smart Grids and Energy Storage
Note

QC 20181127

Available from: 2018-11-26 Created: 2018-11-26 Last updated: 2019-01-30Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1755-1365

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