@inproceedings{ZengerKennerVolbertetal., author = {Zenger, Gerhard and Kenner, Susanne and Volbert, Klaus and Waas, Thomas and Kucera, Markus}, title = {Acquiring energy data from a medium-voltage grid for future smart grid solutions: A practical smart grid application example realized by use of cellular communication networks of the 2nd and 3rd generation}, series = {Proceedings of the 11th Workshop on Intelligent Solutions in Embedded Systems (WISES), 10-11 Sept. 2013, Pilsen, Czech Republic}, booktitle = {Proceedings of the 11th Workshop on Intelligent Solutions in Embedded Systems (WISES), 10-11 Sept. 2013, Pilsen, Czech Republic}, publisher = {IEEE}, isbn = {978-3-00-042899-9}, pages = {1 -- 8}, abstract = {In this paper we present a practical example of the use of Cellular Communication standards like GPRS and UMTS in a Smart Grid Application. For a more detailed view we demonstrate a possible implementation of Cellular Communication Technologies in a data acquisition application for the collection of energy indicators in a medium-voltage grid. Furthermore, we show a technical overview of relevant and common mobile communication standards available in Germany. The included theoretical examples, Smart Grid scenarios, presented data and results are based on a research project for intelligent power regulation in medium-voltage grids performed in Regensburg (Germany). It is a joint project' of the University of Applied Sciences Regensburg together with a local energy provider and a manufacturer for distribution network systems.}, language = {en} } @inproceedings{MiedlBraun, author = {Miedl, Christian and Braun, J{\"u}rgen}, title = {Powertrain and electric system design of a 800-volt all-electric car}, series = {European Conference on Nanoelectronics and Embedded Systems for Electric Mobility, eMotion in Smart Cities, 24.-28. September, 2012, Bologna, Italy}, booktitle = {European Conference on Nanoelectronics and Embedded Systems for Electric Mobility, eMotion in Smart Cities, 24.-28. September, 2012, Bologna, Italy}, language = {en} } @article{HaumerKralVukovicetal., author = {Haumer, Anton and Kral, Christian and Vukovic, Vladimir and David, Alexander and Hettfleisch, Christian and Huzsvar, Attila}, title = {A Parametrization Scheme for High Performance Thermal Models of Electric Machines using Modelica}, series = {IFAC Proceedings Volumes}, volume = {45}, journal = {IFAC Proceedings Volumes}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1474-6670}, doi = {10.3182/20120215-3-AT-3016.00187}, pages = {1058 -- 1062}, abstract = {Thermal models offer great advantages for enhancement of design, protection and control of electric machines. Detailed thermal models take a great number of time constants into account and provide accurate prediction of the temperatures. However, to parameterize such models detailed geometric data are needed. Whenever such detailed information is not available, or the performance of the detailed models is not satisfying, simplified thermal models as described in this paper are advantageous. The calculation of parameters is described in detail, in order to achieve best accordance with temperatures obtained from measurements or from simulations with detailed thermal models. Thermal resistances are calculated from end temperatures of a test run with constant load (and known losses). Thermal capacitances are obtained using optimization to minimize deviation of simulated and measured temperatures during the whole test run. The thermal model of an asynchronous induction machine with squirrel cage is coupled with an electrical model of the drive. For validation, simulation results of an optimally parameterized simplified model are compared with temperatures obtained by simulation of a detailed thermal model, which in turn has been validated against measurement results, both for continuous duty S1 and intermittent duty S6 (6 minutes no-load followed by 4 minutes of 140\% nominal load). The deviations are not more than 4 K which is quite satisfying.}, language = {en} } @inproceedings{BogomolovKralHaumeretal., author = {Bogomolov, Maxim and Kral, Christian and Haumer, Anton and Lomonova, Elena}, title = {Modeling of permanent magnet synchronous machine with fractional slot windings}, series = {Proceedings IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society ; Ecole de Technologie Superieure de Montreal, Universite du Quebec Montreal, Canada 25 - 28 October, 2012}, booktitle = {Proceedings IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society ; Ecole de Technologie Superieure de Montreal, Universite du Quebec Montreal, Canada 25 - 28 October, 2012}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-4673-2421-2}, issn = {1553-572X}, doi = {10.1109/IECON.2012.6388912}, pages = {1894 -- 1899}, abstract = {This paper focuses on simulation of permanent magnet synchronous machine (PMSM) with fractional-slot windings (FSW) in Modelica. Modeling of the electrical machines with object-oriented approach is shortly described, and a new Modelica library for simulation of electrical machines is introduced. The results of simulation of PMSMs with fractional slot windings are presented and explained. Special attention is paid to the higher harmonics and subharmonics produced by the winding and their influence on machine operation.}, language = {en} } @inproceedings{HaumerKral, author = {Haumer, Anton and Kral, Christian}, title = {Motor Management of Permanent Magnet Synchronous Machines}, series = {Proceedings of the 9th International MODELICA Conference; September 3-5; 2012; Munich; Germany}, booktitle = {Proceedings of the 9th International MODELICA Conference; September 3-5; 2012; Munich; Germany}, editor = {Otter, Martin and Zimmer, Dirk}, publisher = {Link{\"o}ping University Electronic Press}, isbn = {978-91-7519-826-2}, issn = {1650-3686}, doi = {10.3384/ecp12076159}, pages = {159 -- 166}, abstract = {Two state-of-the-art machine designs are mainly used in recent electric and hybrid electric vehicles: asynchronous induction machines with squirrel cage which are robust but need a current component to excite the magnetic field; and permanent magnet synchronous machines which rely on somehow more sensible parts but the magnets are able to excite a magnetic field without current. However; if speed gets high enough to reach the field weakening range; for both machine the field oriented control has to prescribe a field current sufficient to reduce the field not to exceed the voltage limits of the stator circuit. Especially for the permanent magnet synchronous machine this paper investigates whether it is possible to determine an optimal field current for every operation point to minimize either total current consumption or losses.}, language = {en} } @inproceedings{KralHaumerBogomolovetal., author = {Kral, Christian and Haumer, Anton and Bogomolov, Maxim and Lomonova, Elena}, title = {Harmonic wave model of a permanent magnet synchronous machine for modeling partial demagnetization under short circuit conditions}, series = {2012 XXth International Conference on Electrical Machines (ICEM 2012) ; Marseille, France, 2 - 5 September 2012}, booktitle = {2012 XXth International Conference on Electrical Machines (ICEM 2012) ; Marseille, France, 2 - 5 September 2012}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-4673-0142-8}, doi = {10.1109/ICElMach.2012.6349880}, pages = {295 -- 301}, abstract = {This paper proposes a multi domain physical model of permanent magnet synchronous machines, considering electrical, magnetic, thermal and mechanical effects. For each component of the model, the main wave as well as lower and higher harmonic wave components of the magnetic flux and the magnetic potential difference may be considered. The permanent magnets are modeled as discrete azimuthal segments in order to consider possible partial demagnetization effects. For each magnet segment a linearized temperature dependent B-H curve is considered. The main advantage of the presented model is that time transient operational behavior of a permanent magnet synchronous machine can be considered under various electrical, magnetic, thermal and mechanical conditions. The electromagnetic condition of surface magnet machine is compared with finite element analysis.}, language = {en} } @inproceedings{KralHaumerLee, author = {Kral, Christian and Haumer, Anton and Lee, Sang Bin}, title = {Robust thermal model for the estimation of rotor cage and stator winding temperatures of induction machines}, series = {2012 XXth International Conference on Electrical Machines ; Marseille, France, 02.- 05.09.2012}, booktitle = {2012 XXth International Conference on Electrical Machines ; Marseille, France, 02.- 05.09.2012}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-4673-0142-8}, doi = {10.1109/ICElMach.2012.6350127}, pages = {1810 -- 1816}, abstract = {In this paper a new model for the estimation of the stator winding and rotor cage temperatures of induction machines is presented. This model can be used in series applications of machines operated under dynamic load conditions where stator and rotor temperature shall be monitored. The proposed model relies on a simplified lumped element thermal equivalent circuit model where the stator core temperature serves as input quantity. The great advantage of this model is that it covers ambient and cooling conditions inherently. This leads to great simplicity and robustness. The parametrization and validation of the model through experimental data is presented. Advantages, drawbacks and possible implementations are discussed.}, language = {en} } @inproceedings{KralHaumerLee, author = {Kral, Christian and Haumer, Anton and Lee, Sang Bin}, title = {Innovative thermal model for the estimation of permanent magnet and stator winding temperatures}, series = {2012 IEEE Energy Conversion Congress and Exposition (ECCE 2012) ; Raleigh, NC, USA 15.09.-20.09.2012}, booktitle = {2012 IEEE Energy Conversion Congress and Exposition (ECCE 2012) ; Raleigh, NC, USA 15.09.-20.09.2012}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-4673-0803-8}, issn = {2329-3721}, doi = {10.1109/ECCE.2012.6342386}, pages = {2704 -- 2711}, abstract = {In this paper an innovative thermal model for the determination of the temperatures of the permanent magnets and stator windings is presented. This model relies on one temperature sensor located in the stator core of the machine. The estimated stator winding and permanent magnet temperatures are determined by a simplified thermal lumped element network model with only two time constants. Due to the structure of the model and the measured stator core temperature the proposed thermal model is very robust. Distortion of the cooling circuit are inherently sensed such that the model can be used for the online prediction of temperatures. Experimental results based on an interior permanent magnet synchronous machine are presented to validate the presented model.}, language = {en} } @inproceedings{BruecklKrpalRiepl, author = {Br{\"u}ckl, Oliver and Krpal, Ondrej and Riepl, Markus}, title = {Influence of wind and solar energy on the frequency of switching operations of On-Load Tap-Changers (OLTC)}, series = {Proceedings of the 13th International Scientific Conference Electric Power Engineering 2012, EPE 2012; Vol. 2}, booktitle = {Proceedings of the 13th International Scientific Conference Electric Power Engineering 2012, EPE 2012; Vol. 2}, publisher = {EPE}, address = {Brno, Czech Republic}, organization = {Brno University of Technology / Faculty of Electrical Engineering and Communication Department of Electrical Power Engineering and Centre for Research and Utilization of Renewable Energy}, pages = {719 -- 722}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Simulation of ductile crack propagation in high-strength pipeline steel using damage models}, series = {9th International Pipeline Conference 2012 (IPC 2012), Calgary, Canada}, booktitle = {9th International Pipeline Conference 2012 (IPC 2012), Calgary, Canada}, doi = {10.1115/IPC2012-90653}, pages = {7}, abstract = {The performance of engineering design of high-strength steel pipelines has revealed the necessity to revise current design procedures. Therefore, an improved and detailed comprehension of fracture mechanisms and development of failure prediction tools are required in order to derive new design criteria. In last decades the most successful failure prediction tools for steel structures subjected to various type of loading can be encountered in the field of damage mechanics. This paper aims to describe ductile fracture behavior of high-strength steel pipelines by applying three different damage models, Gurson-Tvergaard-Needelman (GTN), Fracture Locus Curve (FLC) and Cohesive Zone (CZ). These models are evaluated regarding their capability to estimate ductile crack propagation in laboratory specimens and linepipe components without adjusting the calibrated parameters. It can be shown that appropriate parameter sets can be identified to reproduce load-deformation and fracture resistance curves accurately. The strain rate effect on the fracture behavior is examined by dynamic tests on the BDWT specimens. Finally, the shortcomings of the applied models are pointed out with the reference to possible extensions and modifications.}, language = {en} }