TY - CHAP A1 - Zenger, Gerhard A1 - Kenner, Susanne A1 - Volbert, Klaus A1 - Waas, Thomas A1 - Kucera, Markus T1 - 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 T2 - Proceedings of the 11th Workshop on Intelligent Solutions in Embedded Systems (WISES), 10-11 Sept. 2013, Pilsen, Czech Republic N2 - 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. KW - Mobile communication KW - Medium voltage KW - Standards KW - Smart grids KW - Feeds KW - Ground penetrating radar Y1 - 2013 UR - https://ieeexplore.ieee.org/document/6664954 SN - 978-3-00-042899-9 SP - 1 EP - 8 PB - IEEE ER - TY - CHAP A1 - Miedl, Christian A1 - Braun, Jürgen T1 - Powertrain and electric system design of a 800-volt all-electric car T2 - European Conference on Nanoelectronics and Embedded Systems for Electric Mobility, eMotion in Smart Cities, 24.-28. September, 2012, Bologna, Italy Y1 - 2012 ER - TY - JOUR A1 - Haumer, Anton A1 - Kral, Christian A1 - Vukovic, Vladimir A1 - David, Alexander A1 - Hettfleisch, Christian A1 - Huzsvar, Attila T1 - A Parametrization Scheme for High Performance Thermal Models of Electric Machines using Modelica JF - IFAC Proceedings Volumes N2 - 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. KW - Electric machines KW - Induction machines KW - Thermal models KW - Model reduction KW - Parameter identification KW - Parameter optimization Y1 - 2012 U6 - https://doi.org/10.3182/20120215-3-AT-3016.00187 SN - 1474-6670 VL - 45 IS - 2 SP - 1058 EP - 1062 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Bogomolov, Maxim A1 - Kral, Christian A1 - Haumer, Anton A1 - Lomonova, Elena T1 - Modeling of permanent magnet synchronous machine with fractional slot windings T2 - 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 N2 - 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. KW - Concentrated KW - fractional slot KW - harmonics KW - Modelica KW - permanent magnet KW - subharmonics KW - synchronous machines KW - Torque KW - windings Y1 - 2012 SN - 978-1-4673-2421-2 SN - 978-1-4673-2419-9 SN - 978-1-4673-2420-5 U6 - https://doi.org/10.1109/IECON.2012.6388912 SN - 1553-572X SP - 1894 EP - 1899 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Haumer, Anton A1 - Kral, Christian ED - Otter, Martin ED - Zimmer, Dirk T1 - Motor Management of Permanent Magnet Synchronous Machines T2 - Proceedings of the 9th International MODELICA Conference; September 3-5; 2012; Munich; Germany N2 - 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. KW - Field Oriented Control KW - Optimization of Field Current KW - permanent magnet synchronous machine Y1 - 2012 SN - 978-91-7519-826-2 U6 - https://doi.org/10.3384/ecp12076159 SN - 1650-3686 SN - 1650-3740 SP - 159 EP - 166 PB - Linköping University Electronic Press ER - TY - CHAP A1 - Kral, Christian A1 - Haumer, Anton A1 - Bogomolov, Maxim A1 - Lomonova, Elena T1 - Harmonic wave model of a permanent magnet synchronous machine for modeling partial demagnetization under short circuit conditions T2 - 2012 XXth International Conference on Electrical Machines (ICEM 2012) ; Marseille, France, 2 - 5 September 2012 N2 - 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. KW - demagnetization KW - harmonic analysis KW - magnetic fields KW - magnetic flux KW - magnetic potential difference KW - permanent magnet synchronous machine KW - reluctance KW - segmentation KW - temperature Y1 - 2012 SN - 978-1-4673-0142-8 U6 - https://doi.org/10.1109/ICElMach.2012.6349880 SP - 295 EP - 301 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Kral, Christian A1 - Haumer, Anton A1 - Lee, Sang Bin T1 - Robust thermal model for the estimation of rotor cage and stator winding temperatures of induction machines T2 - 2012 XXth International Conference on Electrical Machines ; Marseille, France, 02.- 05.09.2012 N2 - 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. KW - asynchronous machines KW - Cooling KW - dynamic load KW - equivalent circuits KW - lumped element thermal equivalent circuit model KW - Rotors KW - squirrel cage induction machine KW - stators KW - temperature estimation Y1 - 2012 SN - 978-1-4673-0142-8 SN - 978-1-4673-0143-5 SN - 978-1-4673-0141-1 U6 - https://doi.org/10.1109/ICElMach.2012.6350127 SP - 1810 EP - 1816 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Kral, Christian A1 - Haumer, Anton A1 - Lee, Sang Bin T1 - Innovative thermal model for the estimation of permanent magnet and stator winding temperatures T2 - 2012 IEEE Energy Conversion Congress and Exposition (ECCE 2012) ; Raleigh, NC, USA 15.09.-20.09.2012 N2 - 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. KW - Cooling KW - dynamic load KW - lumped element thermal equivalent circuit model KW - permanent magnet machines KW - permanent magnet synchronous machine KW - stators KW - synchronous machines KW - temperature estimation KW - temperature sensors KW - variable speed Y1 - 2012 SN - 978-1-4673-0803-8 SN - 978-1-4673-0802-1 SN - 978-1-4673-0801-4 U6 - https://doi.org/10.1109/ECCE.2012.6342386 SN - 2329-3721 SN - 2329-3748 SP - 2704 EP - 2711 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Brückl, Oliver A1 - Krpal, Ondrej A1 - Riepl, Markus T1 - Influence of wind and solar energy on the frequency of switching operations of On-Load Tap-Changers (OLTC) BT - Electric Power Engineering T2 - Proceedings of the 13th International Scientific Conference Electric Power Engineering 2012, EPE 2012; Vol. 2 Y1 - 2012 SP - 719 EP - 722 PB - EPE CY - Brno, Czech Republic ER - TY - CHAP A1 - Nonn, Aida A1 - Kalwa, Christoph T1 - Simulation of ductile crack propagation in high-strength pipeline steel using damage models T2 - 9th International Pipeline Conference 2012 (IPC 2012), Calgary, Canada N2 - 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. Y1 - 2012 U6 - https://doi.org/10.1115/IPC2012-90653 ER -