@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} } @incollection{KapellerHaumerKraletal., author = {Kapeller, Hansj{\"o}rg and Haumer, Anton and Kral, Christian and Grabner, Christian}, title = {Different Designs of Large Chipper Drives}, series = {Electronic Engineering and Computing Technology}, booktitle = {Electronic Engineering and Computing Technology}, editor = {Ao, Sio-Iong and Gelman, Len}, publisher = {Springer}, address = {Dordrecht}, isbn = {978-90-481-8775-1}, doi = {10.1007/978-90-481-8776-8_9}, pages = {93 -- 104}, abstract = {This paper presents two simulation models for two variants of a large chipper drive used in a paper mill. If a slip ring induction motor is used, the impact of a rotor circuit rheostat with respect to starting behavior and heavy duty load impulses can be examined. Furthermore a speed controlled squirrel cage induction machine will be investigated. The modeling language for both drives is Modelica. The simulation results for both drives are compared and discussed.}, language = {en} } @incollection{KralHaumerGrabner, author = {Kral, Christian and Haumer, Anton and Grabner, Christian}, title = {Determination of Consistent Induction Motor Parameters}, series = {Electronic Engineering and Computing Technology}, volume = {60}, booktitle = {Electronic Engineering and Computing Technology}, editor = {Ao, Sio-Iong and Gelman, Len}, publisher = {Springer}, address = {Dordrecht}, isbn = {978-90-481-8775-1}, doi = {10.1007/978-90-481-8776-8_7}, pages = {71 -- 80}, abstract = {From the rating plate data of an induction motor the nominal efficiency can be determined. Without detailed knowledge of equivalent circuit parameters, partial load behavior cannot be computed. Therefore, a combined calculation and estimation scheme is presented, where the consistent parameters of an equivalent circuit are elaborated, exactly matching the nominal operating point. From these parameters part load efficiencies can be determined.}, language = {en} } @incollection{KralHaumerGrabner, author = {Kral, Christian and Haumer, Anton and Grabner, Christian}, title = {Broken Rotor Bars in Squirrel Cage Induction Machines - Modeling and Simulation}, series = {Electronic Engineering and Computing Technology}, booktitle = {Electronic Engineering and Computing Technology}, editor = {Ao, Sio-Iong and Gelman, Len}, publisher = {Springer}, address = {Dordrecht}, isbn = {978-90-481-8775-1}, doi = {10.1007/978-90-481-8776-8_8}, pages = {81 -- 91}, abstract = {This paper presents a physical model of a squirrel cage induction machine with rotor topology. The machine is modeled in Modelica, an object oriented multi physical modeling system. The presented machine model is used to investigate electrical rotor asymmetries in induction machines. For the case of a single broken rotor bar a simulation model is compared with measurement results.}, language = {en} } @article{KralHaumerGrabner, author = {Kral, Christian and Haumer, Anton and Grabner, Christian}, title = {Consistent Induction Motor Parameters for the Calculation of Partial Load Efficiencies by Means of an Advanced Simulation Model}, series = {Engineering Letters}, volume = {18}, journal = {Engineering Letters}, number = {1}, address = {Hong Kong}, issn = {1816-0948}, abstract = {From the rating plate data of an induction motor the nominal efficiency can be determined. Without detailed knowledge of equivalent circuit parameters, partial load behavior cannot be computed. Therefore, a combined calculation and estimation scheme is presented, where the consistent parameters of an equivalent circuit are elaborated, exactly matching the nominal operating point. From these parameters part load efficiencies can be determined.}, language = {en} } @incollection{GrabnerGraggerKapelleretal., author = {Grabner, Christian and Gragger, Johannes V. and Kapeller, Hansj{\"o}rg and Haumer, Anton and Kral, Christian}, title = {Sensorless PM-Drive Aspects}, series = {Electronic Engineering and Computing Technology}, booktitle = {Electronic Engineering and Computing Technology}, editor = {Ao, Sio-Iong and Gelman, Len}, publisher = {Springer}, address = {Dordrecht}, isbn = {978-90-481-8775-1}, doi = {10.1007/978-90-481-8776-8_3}, pages = {25 -- 35}, abstract = {The development procedure of permanent magnet drives for sensor less operation beginning from standstill under overload conditions has to consider different design aspects coevally. First, the robust rotor position sensing by test signal enforces a design with a strongly different behavior of the spatial dq-oriented differential inductance values. Therefore, the interior rotor magnet array arrangement is from principle predestinated for the controlled sensor less mode including standstill. Fortunately, in order to reduce costs, the distinct reluctance torque capability of such interior magnet arrangement is additionally used for a significantly increased torque by applying a pre-oriented stator current space vectors within the quasi-steady control.}, language = {en} } @inproceedings{HaumerKral, author = {Haumer, Anton and Kral, Christian}, title = {Enhancements of Electric Machine Models: The EMachines Library}, series = {Proceedings of the 11th International Modelica Conference, Versailles, France, September 21-23, 2015}, volume = {118}, booktitle = {Proceedings of the 11th International Modelica Conference, Versailles, France, September 21-23, 2015}, publisher = {Link{\"o}ping University Electronic Press}, doi = {10.3384/ecp15118509}, pages = {509 -- 515}, abstract = {Transient models of multi phase electric machines are already implemented in the Modelica Standard Library (MSL). However, advanced effects like saturation and skin effect are not taken into account. As an extension to the MSL models, the new EMachines library is presented. This package will be released as a supplemental library to the commercial EDrives library. The particular focus of this paper is on the deep bar effect of induction machines. A comparison of simulation results demonstrates the influence of the skin effect on the operational behavior of the machines. At the end of this publication further developments of the EMachines library will be outlined.}, language = {en} } @inproceedings{BrkicCeranElmoghazyetal., author = {Brkic, Jovan and Ceran, Muaz and Elmoghazy, Mohamed and Kavlak, Ramazan and Haumer, Anton and Kral, Christian}, title = {Open Source PhotoVoltaics Library for Systemic Investigations}, series = {Proceedings of the 13th International Modelica Conference, March 4-6, 2019, Regensburg, Germany}, booktitle = {Proceedings of the 13th International Modelica Conference, March 4-6, 2019, Regensburg, Germany}, publisher = {Link{\"o}ing University Electronic Press}, doi = {10.3384/ecp1915741}, pages = {41 -- 50}, abstract = {For the planning of photovoltaic power plants standard software tools are used. Most of these software tools use statistical solar data to determine the overall energy harvest of a photovoltaic plant over one year. The calculations rely on stationary location and ideal boundary conditions, e.g., constant ambient temperature. Even though, for example, shadowing may be considered by standard software, the investigation of untypical configurations and problems cannot be performed by such software, as most configurations cannot be changed by the user. The presented PhotoVoltaics library was developed with the intention to provide a flexible framework for standard and non-standard problems. Particularly, the PhotoVoltaics library can be coupled with other Modelica libraries to perform systemic investigations. An application library, PhotoVoltaics_TGM, is provided as add-on, where measured data of two photovoltaic pants of the TGM in Vienna can be compared with simulation results. This add-on library serves as validation of the PhotoVoltaics library.}, language = {en} } @inproceedings{EberhartChungHaumeretal., author = {Eberhart, Philip and Chung, Tek Shan and Haumer, Anton and Kral, Christian}, title = {Open Source Library for the Simulation of Wind Power Plants}, series = {Proceedings of the 11th International Modelica Conference, Versailles, France, September 21-23, 2015}, booktitle = {Proceedings of the 11th International Modelica Conference, Versailles, France, September 21-23, 2015}, address = {Link{\"o}ping}, doi = {10.3384/ecp15118929}, pages = {929 -- 936}, abstract = {This paper presents the new open source Modelica libraryWindPowerPlants. For the economic assessment of either a wind power plant or an entire wind park, the accurate prediction of the energy output is essential. Such prediction is usually performed by means of calculations based on statistical wind data. The proposed WindPowerPlants library is capable of assessing the energy output both for statistical and real wind data based on time domain simulations. In the presented version of the library wind turbine models are modeled with pitch control. The generator models have variable speed and an optional connector to the mains. The entire library is based on power balance conditions and losses are fully neglected. Yet, the library can be extended towards more detailed models considering different types of losses. The structure and components of the library are presented. Simulations examples are shown and compared with reference data. The applicability of the proposed WindPowerPlants library is demonstrated and possible enhancements are discussed.}, language = {en} } @article{KralHaumerLee, author = {Kral, Christian and Haumer, Anton and Lee, Sang Bin}, title = {A Practical Thermal Model for the Estimation of Permanent Magnet and Stator Winding Temperatures}, series = {IEEE Transactions on Power Electronics}, volume = {29}, journal = {IEEE Transactions on Power Electronics}, number = {1}, publisher = {IEEE}, issn = {1941-0107}, doi = {10.1109/TPEL.2013.2253128}, pages = {455 -- 464}, abstract = {A thermal model for the determination of the temperatures of interior permanent magnets and stator windings is presented in this paper. The innovation of the model relies on one temperature sensor being located in the stator core of the machine. Such sensor is simple to implement in many applications such as traction or EV, where reliability is critical. The estimated stator winding and permanent magnet temperatures are determined by a simplified thermal lumped element network model with only two time constants. It is shown that the proposed thermal model is very robust due to the structure of the model and the measured stator core temperature. The distortion of the temperature estimates caused by the cooling circuit is inherently accounted for such that the model can be used for robust online prediction of temperatures. Experimental results based on a forced water-cooled interior permanent magnet synchronous machine setup are presented to validate the effectiveness of the presented model.}, language = {en} }