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Leijon, Mats
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Publications (10 of 270) Show all publications
Savin, A., Strömstedt, E. & Leijon, M. (2019). Full-Scale Measurement of Reaction Force Caused by Level Ice Interaction on a Buoy Connected to a Wave Energy Converter. Journal of cold regions engineering, 33(2), Article ID 04019001.
Open this publication in new window or tab >>Full-Scale Measurement of Reaction Force Caused by Level Ice Interaction on a Buoy Connected to a Wave Energy Converter
2019 (English)In: Journal of cold regions engineering, ISSN 0887-381X, E-ISSN 1943-5495, Vol. 33, no 2, article id 04019001Article in journal (Refereed) Published
Abstract [en]

Wave energy is an attractive source of renewable energy. In regions with a cold climate, for example, in the Baltic Sea, a good understanding of ice loads is vital for developing a reliable and cost-effective buoy for a wave energy converter (WEC). The first full-scale attempt was made to measure the vertical reaction force on a floating buoy connected to the WEC under the ice level interaction process. The force equation for a buoy connected to the WEC during the ice level interaction process is presented. It provides essential information on forces from the floating level of ice, which is very important for the design and construction of a buoy in regions with a cold climate.

Place, publisher, year, edition, pages
ASCE-AMER SOC CIVIL ENGINEERS, 2019
Keywords
Renewable energy, Ice level interaction, Vertical reaction force, Crushing force from drifted ice
National Category
Energy Engineering
Identifiers
urn:nbn:se:uu:diva-382809 (URN)10.1061/(ASCE)CR.1943-5495.0000175 (DOI)000464574000006 ()
Funder
Swedish Energy AgencyStandUp
Available from: 2019-05-07 Created: 2019-05-07 Last updated: 2019-05-07Bibliographically approved
Parwal, A., Fregelius, M., Leijon, J., Chatzigiannakou, M. A., Svensson, O., Strömstedt, E., . . . Leijon, M. (2019). Grid Integration and a Power Quality Assessment of a Wave Energy Park. IET Smart Grid, 1-14
Open this publication in new window or tab >>Grid Integration and a Power Quality Assessment of a Wave Energy Park
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2019 (English)In: IET Smart Grid, ISSN 2515-2947, p. 1-14Article in journal (Refereed) Published
Abstract [en]

This paper presents a step towards the grid connection of a wave energy park through an electric power conversion system(EPCS)developed and installed for the wave energy harvesting in Lysekil, Sweden.TheEPCScomprises ofa rectifier,aDC-bus,andan inverterfollowedbyaharmonic filter. The higher and lowerorder harmonics injected bythe inverterin a power quality contextare investigated. The lowerorder voltage harmonics partially distort the voltage sourceinverter(VSI)outputgridcurrent.Aphase-lockedloop(PLL)basedgridphasetrackingisusedtoattenuatethelowerorder harmonicsbyreflectingthegridharmonicsintheinverteroutput.Anexpressionforthegridcurrentharmonicsasafunctionofthe gridvoltageharmonicshasbeenderived and implemented. AmathematicalmodelisderivedtoobtainatransferfunctionforthePLLand finally,PI-gainsaretunedforastablesystemoperation.Aharmonicfilterfor mitigatingthehigherorderharmonicshas beenimplemented. The total harmonic distortion (THD) is evaluated experimentally and theresults fulfill the gridcoderequirementsat various frequencies and harmonic orders.

Place, publisher, year, edition, pages
UK: , 2019
Keywords
WAVE ENERGY SMART GRID HARMONIC DISTORTION
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-389779 (URN)10.1049/iet-stg.2019.0009 (DOI)
Funder
Swedish Research Council, 2015-03126
Available from: 2019-07-25 Created: 2019-07-25 Last updated: 2019-08-19
Hultman, E. & Leijon, M. (2019). Integration of Real-World Project Tasks in a Course on Automation and Robot Engineering. In: Ashmawy, AK Schreiter, S (Ed.), Proceedings of 2019 IEEE Global Engineering Education Conference (EDUCON): . Paper presented at 10th IEEE Global Engineering Education Conference (EDUCON), APR 09-11, 2019, Dubai, U ARAB EMIRATES (pp. 107-114). IEEE
Open this publication in new window or tab >>Integration of Real-World Project Tasks in a Course on Automation and Robot Engineering
2019 (English)In: Proceedings of 2019 IEEE Global Engineering Education Conference (EDUCON) / [ed] Ashmawy, AK Schreiter, S, IEEE, 2019, p. 107-114Conference paper, Published paper (Refereed)
Abstract [en]

The modern engineering profession requires classical technical skills combined with creativity and a high proficiency in cooperation and sustainable development. Research indicates that the engineering education should adapt better to this. This paper introduces a teaching approach where open-ended project tasks are fully integrated into a complete course, in a context relating to the students' future working life. The teaching approach was implemented in a course on automation and robot engineering. Extensive written student course evaluations, the students' examination results and the teachers' experience were used for evaluation and compared with the previous classical course. Both the students and the teachers greatly appreciated the course. It was strongly indicated that the students' theoretical knowledge and understanding of the subject had benefited, both with regards to the technical depth and to the non-technical engineering skills. It is likely that the presented teaching approach can be used also in other engineering courses.

Place, publisher, year, edition, pages
IEEE, 2019
Series
IEEE Global Engineering Education Conference, ISSN 2165-9567
Keywords
engineering education, project organized learning, course construction, active learning, robotics
National Category
Learning Pedagogical Work
Identifiers
urn:nbn:se:uu:diva-390347 (URN)10.1109/EDUCON.2019.8725198 (DOI)000475690400019 ()978-1-5386-9506-7 (ISBN)
Conference
10th IEEE Global Engineering Education Conference (EDUCON), APR 09-11, 2019, Dubai, U ARAB EMIRATES
Available from: 2019-08-08 Created: 2019-08-08 Last updated: 2019-08-08Bibliographically approved
Lindblad, L., Kamf, T., Risberg, A. & Leijon, M. (2019). Portable Data Acquisition System for Offshore Applications. IEEE Journal of Oceanic Engineering, 44(3), 719-727
Open this publication in new window or tab >>Portable Data Acquisition System for Offshore Applications
2019 (English)In: IEEE Journal of Oceanic Engineering, ISSN 0364-9059, E-ISSN 1558-1691, Vol. 44, no 3, p. 719-727Article in journal (Refereed) Published
Abstract [en]

In the development of ocean energy technologies, full-scale sea trials have proven technically challenging and expensive. As a contribution to the development of flexible, reliable, and affordable measurement systems for such sea trials, this paper presents and evaluates a portable data acquisition system. The system offers a cheap and flexible option for when and where signal infrastructure at site is not available. It is battery powered and consists of a sensor system and a logger unit. The sensor system is placed inside the object of study, which for this application is a wave power generator standing on the seafloor. The logger unit, which contains a logger with integrated data storage and a battery, is placed outside the object of study in a submersible and retrievable vessel. Sensor output is carried with 4-20-mA current signals between the sensor system and the logger, which makes the system directly compatible with a wide range of industrial sensors. For the specific setup implemented in this paper, the sensor system was used to measure voltage and current inside the generator. Beyond this, the system is designed to be adaptable for a wider range of sensors, with 16 individual signals and a sampling frequency up to 1 kHz. The custom logger is programmable and offers many options to apply different logging schedules and to limit the sensor system power supply accordingly. Evaluations show that the implemented system offers 5-22 weeks of 1-kHz and 16-bmonitoring of 16 signals, depending on a chosen logging schedule. Suggestions are also given for how to raise the operation time up to 50 weeks. The system has been tested offshore for the collection of power production data from two wave energy converters, with good results.

Keywords
Data Acquisition, Ocean Energy, Wave Power, Logger, Offshore Measurments
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-329827 (URN)10.1109/JOE.2018.2840398 (DOI)000476752900016 ()
Funder
StandUp
Available from: 2017-09-21 Created: 2017-09-21 Last updated: 2019-08-27Bibliographically approved
Parwal, A., Fregelius, M., Cardosa Silva, D., Potapenko, T., Hjalmarsson, J., Kelly, J., . . . Leijon, M. (2019). Virtual Synchronous Generator Based Current Synchronous Detection Scheme for a Virtual Inertia Emulation in SmartGrids. Energy and Power Engineering, 11(3), 99-131
Open this publication in new window or tab >>Virtual Synchronous Generator Based Current Synchronous Detection Scheme for a Virtual Inertia Emulation in SmartGrids
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2019 (English)In: Energy and Power Engineering, ISSN 1949-243X, E-ISSN 1947-3818, Vol. 11, no 3, p. 99-131Article in journal (Refereed) Published
Abstract [en]

Renewable energy sources, such as photovoltaicwind turbines, and wave power converters, use power converters to connect to the grid which causes a loss in rotational inertia. The attempt to meet the increasing energy demand means that the interest for the integration of renewable energy sources in the existing power system is growing, but such integration poses challenges to the operating stability. Power converters play a major role in the evolution of power system towards SmartGrids, by regulating as virtual synchronous ge-nerators. The concept of virtual synchronous generators requires an energy storage system with power converters to emulate virtual inertia similar to the dynamics of traditional synchronous generators. In this paper, a dynamic droop control for the estimation of fundamental reference sources is imple-mented in the control loop of the converter, including active and reactive power components acting as a mechanical input to the virtual synchronous generator and the virtual excitation controller. An inertia coefficient and a droop coefficient are implemented in the control loop. The proposed con-troller uses a current synchronous detection scheme to emulate a virtual iner-tia from the virtual synchronous generators. In this study, a wave energy converter as the power source is used and a power management of virtual synchronous generators to control the frequency deviation and the terminal voltage is implemented. The dynamic control scheme based on a current synchronous detection scheme is presented in detail with a power manage-ment control. Finally, we carried out numerical simulations and verified the scheme through the experimental results in a microgrid structure.

Place, publisher, year, edition, pages
Scientific Research Publishing, 2019
Keywords
Dynamic Droop Control, Energy Storage, Virtual Inertia, Virtual Synchronous Generator
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-379215 (URN)10.4236/epe.2019.113007 (DOI)
Funder
Swedish Research Council, 2015-03126StandUp
Available from: 2019-03-13 Created: 2019-03-13 Last updated: 2019-08-19Bibliographically approved
Hultman, E. & Leijon, M. (2018). An updated cable feeder tool design for robotized stator cable winding. Mechatronics (Oxford), 49, 197-210
Open this publication in new window or tab >>An updated cable feeder tool design for robotized stator cable winding
2018 (English)In: Mechatronics (Oxford), ISSN 0957-4158, E-ISSN 1873-4006, Vol. 49, p. 197-210Article in journal (Refereed) Published
Abstract [en]

We have previously suggested a method for robotized stator winding of cable wound electric machines and demonstrated the method successfully in full-scale experiments. The cable feeder tool used to handle the cable during the complete winding process is an essential component of this robot cell. To take the robot winding method to the next level, into an industrial product, require further developments regarding durability, independency, flexibility and implementability. In this paper, we present an updated cable feeder tool design. This tool is designed to be used in a robot cell for cable winding of the third-generation design of the Uppsala University Wave Energy Converter generator stator. In this work, three cable feeder tool prototypes have been constructed, experimentally evaluated and validated for the intended application. Key performance parameters are presented and discussed, including suggestions for further developments. We completed a durable, compact, high performance tool design, with fully integrated control into industrial robot controllers. The experimental results presented in this article are very promising and hence, the updated cable feeder tool design represents another important step towards an industrial solution for robotized stator cable winding.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Robotics Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-334553 (URN)10.1016/j.mechatronics.2018.01.006 (DOI)000425199700018 ()
Available from: 2017-11-23 Created: 2017-11-23 Last updated: 2019-06-28Bibliographically approved
Parwal, A., Fregelius, M., Temiz, I., Göteman, M., Oliveira, J. G., Boström, C. & Leijon, M. (2018). Energy management for a grid-connected wave energy park through a hybrid energy storage system. Applied Energy, 231, 399-411
Open this publication in new window or tab >>Energy management for a grid-connected wave energy park through a hybrid energy storage system
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2018 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 231, p. 399-411Article in journal (Refereed) Published
Abstract [en]

The concern for climate change and energy consumption has increased the demand for renewable energy production considerably. Marine energy sources attract attention because of their high energy density. Wave energy is an attractive renewable energy source with large potential. Due to the nature of the ocean waves, a linear wave energy converter generates intermittent power. It is therefore crucial to regularize the power before connecting to the grid. Energy storage systems present effective ways to minimize the power fluctuations and deliver a steady power to the grid. In this paper, we present an energy management control system with a dynamic rate limiter. The method is applied to control a hybrid energy storage system, combining battery and supercapacitor, with a fully active topology controlled by the power converters. The results show that the method is able to control the charging and discharging states of the battery and the supercapacitor, and minimize the power fluctuation to the grid. The algorithm ensures low losses by shifting the required power and the stored power smoothly over the energy storage system.

Keywords
Wave energy converter, Hybrid energy storage system, Energy management control system, Dynamic rate limiter, State of charge
National Category
Energy Systems
Identifiers
urn:nbn:se:uu:diva-361207 (URN)10.1016/j.apenergy.2018.09.146 (DOI)000452345400030 ()
Funder
StandUpSwedish Research Council, 2015-03126Carl Tryggers foundation
Available from: 2018-09-21 Created: 2018-09-21 Last updated: 2019-08-19Bibliographically approved
Parwal, A., Fregelius, M., Leijon, J., Chatzigiannakou, M., Svensson, O., Temiz, I., . . . Leijon, M. (2018). Experimental Test of Grid Connected VSC to Improve the Power Quality in a Wave Power System. In: 2018 5TH INTERNATIONAL CONFERENCE ON ELECTRIC POWER AND ENERGY CONVERSION SYSTEMS (EPECS).: . Paper presented at 5th International Conference on Electric Power and Energy Conversion Systems (EPECS), APR 23-25, 2018, Kitakyushu, JAPAN..
Open this publication in new window or tab >>Experimental Test of Grid Connected VSC to Improve the Power Quality in a Wave Power System
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2018 (English)In: 2018 5TH INTERNATIONAL CONFERENCE ON ELECTRIC POWER AND ENERGY CONVERSION SYSTEMS (EPECS)., 2018Conference paper, Published paper (Refereed)
Abstract [en]

This paper provides an overview of electric power conversion system installed at the Lysekil research site, located at the west coast of Sweden. The electric power conversion system consists of rectifiers, rectifying the power from the wave energy converters, a DC-link and a grid-tied inverter. The paper focuses on the performance of the inverter and the filter and presents experimental results obtained during the grid integration.

Series
International Conference on Electric Power and Energy Conversion Systems, ISSN 2325-2677
Keywords
wave energy converter (WEC), wave energy havesting, grid integration, LCL filter response
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-373349 (URN)10.1109/EPECS.2018.8443488 (DOI)000450072100010 ()978-1-5386-6457-5 (ISBN)
Conference
5th International Conference on Electric Power and Energy Conversion Systems (EPECS), APR 23-25, 2018, Kitakyushu, JAPAN.
Funder
Swedish Research Council, 2015-03126Swedish Energy AgencyStandUp
Available from: 2019-01-15 Created: 2019-01-15 Last updated: 2019-01-22Bibliographically approved
Parwal, A., Fregelius, M., Leijon, J., Chatzigiannakou, M. A., Svensson, O., Temiz, I., . . . Leijon, M. (2018). Experimental Test of Grid Connected VSC to Improve the Power Quality in a Wave Power System. In: : . Paper presented at Fifth International Conference on Electric Power and Energy Conversion Systems (EPECS 2018), Kitakyushu, Japan : April 23-25, 2018.
Open this publication in new window or tab >>Experimental Test of Grid Connected VSC to Improve the Power Quality in a Wave Power System
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2018 (English)Conference paper, Published paper (Refereed)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Meteorology and Atmospheric Sciences
Identifiers
urn:nbn:se:uu:diva-361208 (URN)
Conference
Fifth International Conference on Electric Power and Energy Conversion Systems (EPECS 2018), Kitakyushu, Japan : April 23-25, 2018
Available from: 2018-09-21 Created: 2018-09-21 Last updated: 2019-08-19Bibliographically approved
Potapenko, T., Temiz, I. & Leijon, M. (2018). Optimization of Resistive Load for a Wave Energy Converter with a Linear Generator Power Take Off. In: The 4th Asian Wave and Tidal Energy Conference in Taiper, Taiwan, September 9-13, 2018.: . Paper presented at 4th AWTEC2018, 9-13 September, 2018, Taipei, Taiwan.
Open this publication in new window or tab >>Optimization of Resistive Load for a Wave Energy Converter with a Linear Generator Power Take Off
2018 (English)In: The 4th Asian Wave and Tidal Energy Conference in Taiper, Taiwan, September 9-13, 2018., 2018Conference paper, Oral presentation with published abstract (Refereed)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-362233 (URN)
Conference
4th AWTEC2018, 9-13 September, 2018, Taipei, Taiwan
Available from: 2018-10-02 Created: 2018-10-02 Last updated: 2019-01-09Bibliographically approved
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