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Samadaei, E., Kaviani, M. & Bertilsson, K. (2019). A 13-levels Module (K-Type) with two DC sources for Multilevel Inverters. IEEE transactions on industrial electronics (1982. Print), 66(7), 5186-5196
Open this publication in new window or tab >>A 13-levels Module (K-Type) with two DC sources for Multilevel Inverters
2019 (English)In: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, Vol. 66, no 7, p. 5186-5196Article in journal (Refereed) Published
Abstract [en]

This paper presents a new reconfiguration module for asymmetrical multilevel inverters in which the capacitors are used as the DC links to creates the levels for staircase waveforms. This configuration of multilevel converter makes a reduction in DC sources. On the other hand, it is possible to generate 13 levels with lower DC sources. The proposed module of multilevel inverter generates 13 levels with two unequal DC sources (2VDC and 1VDC). It also involves two chargeable capacitors and 14 semiconductor switches. The capacitors are self-charging without any extra circuit. The lower number of components makes it desirable to use in wide range of applications. The module is schematized as two back-to-back T-type inverters and some other switches around it. Also, it can be connected as cascade modular which lead to a modular topology with more voltage levels at higher voltages. The proposed module makes the inherent creation of the negative voltage levels without any additional circuit (such as H-bridge circuit). Nearest level control switching modulation (NLC) scheme is applied to achieve high quality sinusoidal output voltage. Simulations are executed in MATLAB/Simulink and a prototype is implemented in the power electronics laboratory which the simulation and experimental results show a good performance.

Keywords
Asymmetric, capacitors, multilevel inverter, nearest level control switching, power electronics, self-charging
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-34710 (URN)10.1109/TIE.2018.2868325 (DOI)000460663300021 ()2-s2.0-85053154849 (Scopus ID)
Available from: 2018-10-12 Created: 2018-10-12 Last updated: 2019-10-16Bibliographically approved
Vijeh, M., Rezanejad, M., Samadaei, E. & Bertilsson, K. (2019). A General Review of Multilevel Inverters Based on Main Submodules: Structural Point of View. IEEE transactions on power electronics, 34(10), 9479-9502
Open this publication in new window or tab >>A General Review of Multilevel Inverters Based on Main Submodules: Structural Point of View
2019 (English)In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 34, no 10, p. 9479-9502Article in journal (Refereed) Published
Abstract [en]

Multilevel inverters (MLIs) are being used in wide range of power electronics applications. These converters that are attracted a lot of attentions during recent years have different topologies with similar basic concept. This paper presents five main submodules (SMs) that are used as the basic structures of MLIs. The paper reviews the common multilevel inverter topologies with the structural point of view. The topologies are divided to main SMs to show conventional MLIs configuration and future topologies that can be created from the main SMs. The comparative study on topologies is investigated with details. The MLIs are categorized and investigated with due attention to some indexes such as the number of components, the ability to create inherent negative voltage, working in regeneration mode and using single DC source.

Keywords
Asymmetric, multilevel inverter (MLI), power electronics, symmetric
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-35505 (URN)10.1109/TPEL.2018.2890649 (DOI)000474581900014 ()2-s2.0-85063804140 (Scopus ID)
Available from: 2019-01-23 Created: 2019-01-23 Last updated: 2019-10-16Bibliographically approved
Alishah, R. S., Hasani, M. Y., Hosseini, S. H., Bertilsson, K. & Babalou, M. (2019). Analysis and Design of a New Extendable Sepic Converter with High Voltage Gain and Reduced Components for Photovoltaic Applications. In: 2019 10th International Power Electronics, Drive Systems and Technologies Conference (PEDSTC): . Paper presented at 10th Annual International Power Electronics, Drive Systems and Technologies Conference (PEDSTC2019) (pp. 492-497). IEEE, Article ID 8697249.
Open this publication in new window or tab >>Analysis and Design of a New Extendable Sepic Converter with High Voltage Gain and Reduced Components for Photovoltaic Applications
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2019 (English)In: 2019 10th International Power Electronics, Drive Systems and Technologies Conference (PEDSTC), IEEE, 2019, p. 492-497, article id 8697249Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents a high step-up DC-DC converter which is appropriate for Photovoltaic systems. This topology has been combined from an extended switched-capacitor and a common SEPIC converter. Low components and high-voltage-gain are the main benefits of the introduced topology. Low rate current ripple, easy control and continuous input current are other advantages of the presented structure. Integrating the switched-capacitor with the SEPIC converter leads to increase the output voltage with variable conversion ratio which can be used for a wide range of loads. The switched-capacitor converter provides a constant dc output voltage while the SEPIC converter extracts maximum power of PV panels because it operates under control of duty cycle. Continuous input current is highly suitable for PV applications. The operating principles and steady-state analysis of the suggested topology are discussed in detail. In order to assess the effectiveness of the presented topology, it has been simulated on PSCAD/EMTDC software.

Place, publisher, year, edition, pages
IEEE, 2019
Keywords
SEPIC converter, Switched-capacitor, High dc output voltage, Photovoltaic applications
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-35503 (URN)10.1109/PEDSTC.2019.8697249 (DOI)000469800900085 ()2-s2.0-85065477474 (Scopus ID)978-1-5386-9254-7 (ISBN)
Conference
10th Annual International Power Electronics, Drive Systems and Technologies Conference (PEDSTC2019)
Available from: 2019-01-23 Created: 2019-01-23 Last updated: 2019-07-09Bibliographically approved
Akram, S., Alam, F. M., Bertilsson, K. & Sidén, J. (2019). Capacitive and optical sensing for automatic detection and characterization of cleaning sponges in fiber optic microduct installations. In: Proceedings - 2019 8th International Workshop on Advances in Sensors and Interfaces, IWASI 2019: . Paper presented at 8th International Workshop on Advances in Sensors and Interfaces, IWASI 2019, Otranto, Italy, 13 June 2019 through 14 June 2019 (pp. 274-278). IEEE, Article ID 8791315.
Open this publication in new window or tab >>Capacitive and optical sensing for automatic detection and characterization of cleaning sponges in fiber optic microduct installations
2019 (English)In: Proceedings - 2019 8th International Workshop on Advances in Sensors and Interfaces, IWASI 2019, IEEE, 2019, p. 274-278, article id 8791315Conference paper, Published paper (Refereed)
Abstract [en]

Optical fiber duct installation requires blowing of cleaning sponges for dirt and moisture removal before blowing the fiber cables. The traditional method requires one operator that blows the sponge and one operator in the receiving end that manually evaluate the sponges until a dry sponge is received. The proposed system eliminates the need of a second operator by introducing a solution for automatic sponge detection and characterization of moisture in sponges at the receiving end. An optical sensor is used for detection and a capacitive sensor is developed to measure the sponge's wetness. Sensor data is automatically transmitted back to the operator at the feeding end via a mobile phone. The system is characterized to work with sponges ranging from saturated with wetness to what is deemed as dry. 

Place, publisher, year, edition, pages
IEEE, 2019
Keywords
Capacitive sensor, Optical fiber cable blowing, Optical Fiber Duct, Optical Sensor
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-37305 (URN)10.1109/IWASI.2019.8791315 (DOI)2-s2.0-85071433558 (Scopus ID)978-1-7281-0557-4 (ISBN)
Conference
8th International Workshop on Advances in Sensors and Interfaces, IWASI 2019, Otranto, Italy, 13 June 2019 through 14 June 2019
Available from: 2019-09-24 Created: 2019-09-24 Last updated: 2019-09-24Bibliographically approved
Das, M. & Bertilsson, K. (2019). GaN Based Converters for Battery Charging Application of Electric Vehicle. In: IECON2019: . Paper presented at IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society.
Open this publication in new window or tab >>GaN Based Converters for Battery Charging Application of Electric Vehicle
2019 (English)In: IECON2019, 2019Conference paper, Published paper (Refereed)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-37563 (URN)
Conference
IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society
Available from: 2019-10-22 Created: 2019-10-22 Last updated: 2019-10-22
Barg, S. & Bertilsson, K. (2019). Multi‑objective Pareto and GAs nonlinear optimization approach for fyback transformer. Electrical engineering (Berlin. Print), 101(3), 995-1006
Open this publication in new window or tab >>Multi‑objective Pareto and GAs nonlinear optimization approach for fyback transformer
2019 (English)In: Electrical engineering (Berlin. Print), ISSN 0948-7921, E-ISSN 1432-0487, Vol. 101, no 3, p. 995-1006Article in journal (Refereed) Published
Abstract [en]

Design and optimization of high-frequency inductive components is a complex task because of the huge number of variables to manipulate, the strong interdependence and the interaction between variables, the nonlinear variation of some design variables as well as the problem nonlinearity. This paper proposes a multi-objective design methodology of a 200-W flyback transformer in continuous conduction mode using genetic algorithms and Pareto optimality concept. The objective is to minimize loss, volume and cost of the transformer. Design variables such as the duty cycle, the winding configuration and the core shape, which have great effects on the former objectives but were neglected in previous works, are considered in this paper. The optimization is performed in discrete research space at different switching frequencies. In total, 24 magnetic materials, 6 core shapes and 2 winding configurations are considered in the database. Accurate volume and cost models are also developed to deal with the optimization in the discrete research space. The bi-objective (loss–volume) and tri-objective (loss–volume–cost) optimization results are presented, and the variations of the design variables are analyzed for the case of 60 kHz. An example of a design (30 kHz) is experimentally verified. The registered efficiency is 88% at full load.

Place, publisher, year, edition, pages
Germany: Springer Berlin/Heidelberg, 2019
Keywords
Genetic algorithms, NSGAII, Pareto front, Flyback converter, Transformer, Core loss, Winding loss
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-37384 (URN)10.1007/s00202-019-00836-3 (DOI)2-s2.0-85074033042 (Scopus ID)
Projects
WIRIC
Available from: 2019-09-26 Created: 2019-09-26 Last updated: 2019-11-15Bibliographically approved
Bakar, M. A., Alam, F. M., Barg, S. & Bertilsson, K. (Eds.). (2019). Reconfigurable three state dc-dc power converter for the wide output range applications. Paper presented at IEEE Institute of Industrial Electronics, Proceedings of IECON2019, 14-17 Oct, 2019, Lisbon. Lisbon: IEEE conference proceedings
Open this publication in new window or tab >>Reconfigurable three state dc-dc power converter for the wide output range applications
2019 (English)Conference proceedings (editor) (Refereed)
Abstract [en]

Improving the dc voltage gain of power converters has been the primary focus of the current and past research in the area of power electronics. This work presents another solution to widen the range of the output voltage. It proposes three reconfigurable steps for the output voltage. The range of the output voltage varies up to four times the base level. These configurations together vary the output voltage from 15 to 96 volts. A soft switched dc-dc power converter is built with the traditional topology of phase shifted full bridge converter along with improved characteristics. For better management of the transformer loss, a configuration of four transformers has been employed. The proportional gate drive approach is implemented to obtain four similar isolated blocks of the output voltage. This makes it possible to either configure these blocks all in series, parallel or in series/ parallel combination of two. The concept is verified in a low-profile prototype. The hardware is characterized up to the load power of 1kW for the input voltage of 400Vdc. The converter reports better efficiency over the complete range of output voltage.

Place, publisher, year, edition, pages
Lisbon: IEEE conference proceedings, 2019. p. 6
Keywords
DC-DC power converters, State of the art power converters, Low profile converters
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-37602 (URN)
Conference
IEEE Institute of Industrial Electronics, Proceedings of IECON2019, 14-17 Oct, 2019, Lisbon
Available from: 2019-11-01 Created: 2019-11-01 Last updated: 2019-11-01
Bakar, M. A., Alam, F. M., Barg, S., Moumita, D. & Bertilsson, K. (2019). Reconfigurable three state dc-dc power converter forthe wide output range applications. In: IECON2019: . Paper presented at 45th Proceedings of inductrial electronics, Libson, Portugal. Lisbon: IEEE
Open this publication in new window or tab >>Reconfigurable three state dc-dc power converter forthe wide output range applications
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2019 (English)In: IECON2019, Lisbon: IEEE, 2019Conference paper, Published paper (Refereed)
Abstract [en]

Improving the dc voltage gain of power convertershas been the primary focus of the current and past research in thearea of power electronics. This work presents another solution towiden the range of the output voltage. It proposes threereconfigurable steps for the output voltage. The range of theoutput voltage varies up to four times the base level. Theseconfigurations together vary the output voltage from 15 to 96 volts.A soft switched dc-dc power converter is built with the traditionaltopology of phase shifted full bridge converter along withimproved characteristics. For better management of thetransformer loss, a configuration of four transformers has beenemployed. The proportional gate drive approach is implementedto obtain four similar isolated blocks of the output voltage. Thismakes it possible to either configure these blocks all in series,parallel or in series/ parallel combination of two. The concept isverified in a low-profile prototype. The hardware is characterizedup to the load power of 1kW for the input voltage of 400Vdc. Theconverter reports better efficiency over the complete range ofoutput voltage.

Place, publisher, year, edition, pages
Lisbon: IEEE, 2019
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-37646 (URN)
Conference
45th Proceedings of inductrial electronics, Libson, Portugal
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2019-11-08
Bakar, M. A., Alam, F. M. & Bertilsson, K. (2016). A phase shifted full bridge converter with novel control over the leakage inductance. In: 2016 18TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'16 ECCE EUROPE): . Paper presented at 18th European Conference on Power Electronics and Applications (EPE), SEP 05-09, 2016, GERMANY. Institute of Electrical and Electronics Engineers (IEEE), Article ID 7695545.
Open this publication in new window or tab >>A phase shifted full bridge converter with novel control over the leakage inductance
2016 (English)In: 2016 18TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'16 ECCE EUROPE), Institute of Electrical and Electronics Engineers (IEEE), 2016, article id 7695545Conference paper, Published paper (Refereed)
Abstract [en]

The electronics industry is progressing towards the high density board solutions due to the requirement of compact and intelligent electronic systems. In order to meet the industry demands, the power system is required to be of high power density. This article proposes one of the solution to improve the power density for the medium power applications. In phase shifted full bridge converter, the intrinsic leakage inductance of the main transformer is not high enough to obtain the zero voltage switching of the power switches for the entire operating conditions. An additional shim inductor is usually connected in series with the primary winding of the main transformer to increase the collective leakage inductance. This additional shim inductor degrades the power density of the converter. This paper proposes a method to embed and control the resonance inductance inside the main transformer. In addition to the increased inter-winding spacing, this paper proposes a practical approach to integrate the ferrite rods inside the main transformer for further increase in the leakage inductance. A power transformer is constructed and investigated by using the modelled equations to estimate the leakage inductance. A prototype phase shifted full bridge converter is also developed to investigate the performance of the proposed transformer. The converter is designed for the switching frequency of 400kHz, and tested up to 600watts output power at the input voltage of 200Vdc. The performance of the proposed converter is also compared with the converter of using an external inductor. The investigations show that, in addition to the improved power density, the converter with the proposed transformer is more efficient than the converter with the traditional transformer.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2016
Series
European Conference on Power Electronics and Applications, ISSN 2325-0313
Keywords
ZVS converter, Transformer, Device modelling, High power density systems, Efficiency
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-29392 (URN)10.1109/EPE.2016.7695545 (DOI)000386637300294 ()2-s2.0-84996605370 (Scopus ID)STC (Local ID)STC (Archive number)STC (OAI)
Conference
18th European Conference on Power Electronics and Applications (EPE), SEP 05-09, 2016, GERMANY
Available from: 2016-12-02 Created: 2016-12-02 Last updated: 2017-06-29Bibliographically approved
Saleem, J., Majid, A., Malik, A. W., Bertilsson, K. & Carlberg, T. (2016). An efficient method of spot welding Aluminium alloys with induction preheating. Journal of Electrical Systems, 12(4), 817-825
Open this publication in new window or tab >>An efficient method of spot welding Aluminium alloys with induction preheating
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2016 (English)In: Journal of Electrical Systems, ISSN 1112-5209, Vol. 12, no 4, p. 817-825Article in journal (Refereed) Published
Abstract [en]

Steel has been the material of choice for automobile manufacturers. In the recent years material such as aluminium and its alloys are taking over the market because of their light weight. The use of aluminium, in automobile manufacturing can result in overall fuel efficiency. Spot welding aluminium alloys require higher electric power and less welding time as compared to steel. Welding guns that can produce an electric current which is approximately 2 to 3 times higher, as compared to steel are required for spot welding aluminium. An efficient method of spot welding Aluminium alloys with the preheating process has been proposed in this paper. Preheating Aluminium sheet before spot welding reduces the thermal and electrical resistance which brings down the electric current requirement to spot weld Aluminium structures. Both spot welding and induction preheating process have been modelled in this paper. The test results of the preheating process have also been verified with practical heating trials. The preheating is performed on-the-fly in advance to spot welding process. The results show that spot welding Al 6082 after preheating up to 200 degrees C, the output current requirements to make the spot weld are reduced by 22%..

Keywords
Finite element method, pre heating, resistance spot welding, induction heating, aluminium welding
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-30095 (URN)000391139200013 ()2-s2.0-85010727858 (Scopus ID)
Available from: 2017-02-10 Created: 2017-02-10 Last updated: 2017-08-08Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-0208-9112

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