@misc{KolmorgenMikulecGoettingetal., author = {Kolmorgen, Stefan and Mikulec, Dragan and Goetting, Gunther and Herranz Gracia, Mercedes and Spannhake, Stefan and Raichle, Daniel and Scheidle, Alexander and Challand, Yves and Beyer, Mario}, title = {Method and Device for Operating an Externally Excited Electric Machine (Patent)}, abstract = {Die Erfindung betrifft ein Verfahren und eine Vorrichtung zum Betrieb einer fremderregten elektrischen Maschine (1), insbesondere Synchronmaschine. Dabei werden mit Hilfe einer Sensorik eine, eine Rotortemperatur (Temp_Rotor) und/oder eine Statortemperatur charakterisierende Gr{\"o}ße bestimmt und ein Erregerstrom (l_E) und Statorstr{\"o}me (l_U, l_V, l_W) f{\"u}r die elektrische Maschine (1) durch eine Steuereinheit (3) zumindest in vorgebbaren Betriebsbereichen in Abh{\"a}ngigkeit von der die Rotortemperatur (Temp_Rotor) und/oder die Statortemperatur charakterisierenden Gr{\"o}ße festgelegt.}, language = {en} } @misc{FrankGrundmannHerranzGraciaetal., author = {Frank, Michael and Grundmann, J{\"o}rn and Herranz Gracia, Mercedes and Nick, Wolfgang}, title = {Helical Winding with Increased Field Use (Patent)}, abstract = {Es wird ein Stator (3) f{\"u}r eine elektrische Wechselstrom-Maschine (1) mit einer magnetischen Polzahl p angegeben, - wobei der Stator (3) eine zentrale Achse A aufweist, - wobei der Stator (3) eine Statorwicklung (4) mit einer Mehrzahl von Leiterwindungen (13j) aufweist, welche jeweils zumindest in einem Teilabschnitt (l) bez{\"u}glich der zentralen Achse (A) helixartig verlaufen, - wobei die einzelnen Leiterwindungen (13j) zu insgesamt n elektrischen Str{\"a}ngen (u1, u2 bis w3, w4) gruppiert sind, dadurch gekennzeichnet, dass die Anzahl n der Str{\"a}nge gr{\"o}ßer als drei ist, insbesondere ein ganzzahliges Vielfaches von drei. Weiterhin wird eine elektrische Maschine (1) mit einem derartigen Stator (3) angegeben.}, language = {en} } @misc{FilipenkoFrankGleixneretal., author = {Filipenko, Mykhaylo and Frank, Michael and Gleixner, Thomas and Grundmann, J{\"o}rn and Herranz Gracia, Mercedes}, title = {Electrical Coil Arrangement Comprising Litz Wire Conductor Segments (Patent)}, abstract = {Es wird eine elektrische Spulenanordnung (21) umfassend wenigstens eine Leiterwindung (wi; wl, w2) mit zwei Leiterzweigen (23a, 23b) beschrieben, von denen der erste Leiterzweig (23a) bez{\"u}glich der vorgegebenen Stromflussrichtung als Hinleiter und der zweite Leiterzweig (23b) bez{\"u}glich dieser Stromflussrichtung als R{\"u}ckleiter ausgebildet ist. Dabei sind die einzelnen Leiterzweige (23a, 23b) als verpresste und mit einem geh{\"a}rteten F{\"u}llmittel (40) in eine stabile Form gebrachte Litzenleiter mit einer Vielzahl von elektrisch leitf{\"a}higen Einzeldr{\"a}hten (38) ausgebildet, wobei jeder einzelne Leiterzweig (23a, 23b) als separates, vorgefertigtes Leitersegment (27) gebildet ist, welches nachtr{\"a}glich in wenigstens einem Endbereich (17) elektrisch leitend mit einem anderen, zugeordneten Leiterzweig (23b, 23a) verbunden ist. Weiterhin werden eine elektrische Maschine (1) mit einer derartigen Spulenanordnung (21) und ein Verfahren zur Herstellung einer solchen Spulenanordnung (21) beschrieben.}, language = {en} } @misc{RuizDeLarramendiHeuserHerranzGracia, author = {Ruiz De Larramendi, Miguel and Heuser, Patrick and Herranz Gracia, Mercedes}, title = {Asynchronous Machine with Optimized Distribution of Electrical Losses Between Stator and Rotor (Patent)}, abstract = {Es wird eine Asynchronmaschine (1) vorgeschlagen, wie sie insbesondere in Elektrofahrzeugen oder Hybridfahrzeugen eingesetzt werden kann. Die Asynchronmaschine (1) weist einen Rotor (5) und einen Stator (3) auf. Die Asynchronmaschine ist derart aufgebaut und angesteuert, dass sie eine Polpaarzahl p von p=3 aufweist. Aufgrund der hierdurch erreichbaren verringerten Jochs{\"a}ttigung kann das Statorjoch (9) mit einer geringeren H{\"o}he hy1 ausgebildet werden, so dass ein Verh{\"a}ltnis von Rotoraußendurchmesser D2a zu Statoraußendurchmesser D1a Werte zwischen 0,7 und 0,8 annehmen kann. Hierdurch lassen sich im Rotor (5) vergr{\"o}ßerte Rotorz{\"a}hne (19) und entsprechend vergr{\"o}ßerte Rotornuten (21) ausbilden, so dass elektrische Verluste in dem als Rotorspulenelement (23) dienenden Material in den Rotornuten (21) im Vergleich zu herk{\"o}mmlichen Asynchronmaschinen geringer sind. Die als Ausgleich in dem Stator (3) verst{\"a}rkt auftretenden elektrischen Verluste f{\"u}hren zu einer geringeren Erw{\"a}rmung des Stators (3) als dies beim Rotor (5) der Fall w{\"a}re, da sich der Stator (3) mit einfachen Mitteln k{\"u}hlen l{\"a}sst. Insgesamt kann somit mit der vorgeschlagenen Asynchronmaschine (1) ein h{\"o}heres Dauerdrehmoment erreicht werden.}, language = {en} } @misc{FrankGrundmannHerranzGraciaetal., author = {Frank, Michael and Grundmann, J{\"o}rn and Herranz Gracia, Mercedes and Nick, Wolfgang}, title = {Helical Winding with More Homogeneous Field Utilisation (Patent)}, abstract = {Helixartige Wicklung mit homogenerer Feldausnutzung Es wird ein Stator (3) f{\"u}r eine elektrische Wechselstrom- Maschine (1) mit einer magnetischen Polzahl p angegeben, - wobei der Stator (3) eine zentrale Achse A aufweist, - wobei der Stator (3) eine Statorwicklung (4) mit einer Mehrzahl von Leiterwindungen (13j) aufweist, - wobei die einzelnen Leiterwindungen (13j) zu insgesamt n elektrischen Str{\"a}ngen (u, v, w) gruppiert sind, - wobei die Leiterwindungen (13j) eines Stranges jeweils wenigstens einen ersten (23a) und einen zweiten Leiterzweig (23b) aufweisen, - wobei diese Leiterzweige (23a, 23b) auf dem {\"u}berwiegenden Teil (1) ihrer L{\"a}nge helixartig um die zentrale Achse (A) angeordnet sind - und wobei diese helixartig angeordneten Leiterzweige (23a, 23b) jeweils eine Gangh{\"o}he h aufweisen, die gr{\"o}ßer ist als das Produkt der axialen L{\"a}nge 1 der helixartigen Leiterzweige (13j) und der Polzahl p. Weiterhin wird eine elektrische Maschine (1) mit einem derartigen Stator (3) angegeben.}, language = {en} } @misc{KelleterRuizDeLarramendiAlexanderetal., author = {Kelleter, Arndt and Ruiz De Larramendi, Miguel and Alexander, Marcus and Herranz Gracia, Mercedes and Heuser, Patrick}, title = {Electric Machine (Patent)}, abstract = {Die Erfindung betrifft eine elektrische Asynchronmaschine (1), insbesondere Induktionsmaschine, umfassend: - einen zylindrischen Stator (2) mit an einem Statorjoch (21) angeordneten Statorz{\"a}hnen (22), wobei ein Verh{\"a}ltnis einer Jochh{\"o}he (hy1) des Statorjochs (21) in radialer Richtung zu einer Nuth{\"o}he (hn1) der Statornuten (23) in radialer Richtung zwischen 1,75 und 2,5 betr{\"a}gt; - einen zylindrischen L{\"a}ufer (4) mit an einem L{\"a}uferjoch angeordneten L{\"a}uferpolen (42), die durch Kurzschlusswicklungen in einem L{\"a}uferk{\"o}rper (41) definiert sind, wobei ein Verh{\"a}ltnis der Jochh{\"o}he des L{\"a}uferk{\"o}rpers (41) in radialer Richtung zur Nuth{\"o}he der L{\"a}ufernuten in radialer Richtung zwischen 2 und 2,75 betr{\"a}gt.}, language = {en} } @inproceedings{SchlensokBrakensiekLessmannetal., author = {Schlensok, Christoph and Brakensiek, D. and Leßmann, M. and Herranz Gracia, Mercedes and Hameyer, Kay and Henneberger, G.}, title = {Simulation of permanent-magnet electrical machines and levitation systems using FEM}, series = {22nd CAD-FEM User's Meeting}, booktitle = {22nd CAD-FEM User's Meeting}, language = {en} } @inproceedings{HerranzGraciaHameyer, author = {Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Multi-objective optimization of an induction machine using design of experiments}, series = {13th Biennial IEEE Conference on Electromagnetic Field Computation, CEFC}, booktitle = {13th Biennial IEEE Conference on Electromagnetic Field Computation, CEFC}, pages = {327 -- 327}, abstract = {The evaluation of the electromagnetic, structural and acoustic behavior of an induction machine is computationaly expensive. Optimization algorithms are therefore not applicable. This papers demonstrates that the methodology of design of experiments (Taguchi method) has been successfully applied for the multi-objective optimization of such multiphysics devices. A significant improvement of the machine performances can be achieved with this approach after only a few evaluations of the coupled FE model}, language = {en} } @inproceedings{HafnerHenrotteHerranzGraciaetal., author = {Hafner, Martin and Henrotte, Francois and Herranz Gracia, Mercedes and Hameyer, Kay}, title = {An energy-based harmonic constitutive law for magnetic cores with hysteresis}, series = {16th International Conference on the Computation of Electromagnetic Fields}, booktitle = {16th International Conference on the Computation of Electromagnetic Fields}, abstract = {In this paper a phenomenogical energy-based harmonic ferromagnetic material model is presented which considers time-dependent hysteresis losses as a part of the material characteristic. The model is based on the effective reluctivity concept and can be applied to simulate hysteresis losses of electromechanic devices. The hysteresis losses of a C-Core are simulated and compared to the results of an iron loss estimation by loss curves.}, language = {en} } @inproceedings{SchlensokvanderGietHerranzGraciaetal., author = {Schlensok, Christoph and van der Giet, Michael and Herranz Gracia, Mercedes and van Riesen, Dirk and Hameyer, Kay}, title = {Structure-Dynamic Analysis of an Induction Machine depending on Stator-Housing Coupling}, series = {6th International Machine and Drives Conference, IEMDC}, booktitle = {6th International Machine and Drives Conference, IEMDC}, publisher = {IEEE}, doi = {10.1109/IEMDC.2007.383657}, abstract = {The estimation and calculation of the acoustic sound of electric machinery is of high interest. Various approaches have been presented relying either on analytical or on numerical models. In general, the analytical models are based on the electromagnetic-field theory and the results are compared to measurements. Numerical models allow for the separation of different exciting forces stemming from various effects. In the studied case of an induction motor with squirrel-cage rotor three effects are taken into account in the analytical model: the fundamental field, saturation, and eccentricity. The numerical analysis is applied for the analysis of acoustic sound of an electric machine. Nevertheless, the numerical results have to be verified. Hence, they are compared to the physically based analytical results. The radiated noise depends directly on the surface's deformation of the machine. Therefore, the analysis is focused on the structure-dynamic vibrations. The combined analysis presented here, allows for the reduction of vibrations and noise optimizing the coupling of stator and housing. Here, an induction machine (IM) with squirrel-cage rotor is studied. Its housing is mounted with six spiral-steel springs to the stator. With the presented method the impact of different numbers of springs is analyzed.}, language = {en} } @inproceedings{HerranzGraciaHameyer, author = {Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Influence of the magnetic anisotropy on electrical machines}, series = {XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ISEF}, booktitle = {XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ISEF}, abstract = {Non grain-oriented electrical steel has an inherent anisotropy, which is normally neglected in the calculation of electrical machines. Moreover, the magnetic anisotropy is usually measured in small material samples. Due to the cutting effect, the magnetic anisotropy in the machine is not the same as in the sample. In this paper, the magnetic anisotropy is considered as a global problem. A method to measure it is presented and its influence on the electromagnetic and acoustic behavior is considered through the example of an induction motor.}, language = {en} } @inproceedings{HerranzGraciaLangeHameyer, author = {Herranz Gracia, Mercedes and Lange, E. and Hameyer, Kay}, title = {Numerical Calculation of Iron Losses in Electrical Machines with a modified Post-Processing Formula}, series = {16th International Conference on the Computation of Electromagnetic Fields, COMPUMAG}, booktitle = {16th International Conference on the Computation of Electromagnetic Fields, COMPUMAG}, language = {en} } @inproceedings{HerranzGraciaHameyer, author = {Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Study of Temperature Rise Problems of Stepper Motors under High Duty Cycle}, series = {42nd International Symposium on Electrical Machines, SME}, booktitle = {42nd International Symposium on Electrical Machines, SME}, language = {en} } @article{SchlensokvanderGietHerranzGraciaetal., author = {Schlensok, Christoph and van der Giet, Michael and Herranz Gracia, Mercedes and van Riesen, Dirk and Hameyer, Kay}, title = {Structure-Dynamic Analysis of an Induction Machine Depending on Stator-Housing Coupling}, series = {IEEE Transactions on Industry Applications}, volume = {44}, journal = {IEEE Transactions on Industry Applications}, number = {3}, issn = {0093-9994}, doi = {10.1109/TIA.2008.921440}, pages = {753 -- 759}, abstract = {The estimation and the calculation of the acoustic sound of electric machinery are of particular interest nowadays. Various approaches have been presented, relying either on analytical or on numerical models. The analytical models presented here are based on the electromagnetic-field theory. Numerical models are applied to derive the exciting forces stemming from various sources and effects. The numerical results have to be verified. Hence, they are compared with the physically based analytical results. The radiated noise depends directly on the surface deformation of the machine. Therefore, the analysis is focused on the structure-dynamic vibration. The combined analysis presented here allows for the reduction of vibration and noise, optimizing the coupling of the machine's stator and housing. The studied induction machine's housing is mounted with six spiral-steel springs to the stator. With the presented method, the impact of different numbers of springs is analyzed exemplarily.}, language = {en} } @article{SchlensokHerranzGraciaHameyer, author = {Schlensok, Christoph and Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Combined Numerical and Analytical Method for Geometry Optimization of a PM Motor}, series = {IEEE Transactions on Magnetics}, volume = {42}, journal = {IEEE Transactions on Magnetics}, number = {4}, publisher = {IEEE}, doi = {10.1109/TMAG.2006.871379}, pages = {1211 -- 1214}, abstract = {For the reduction of the cogging torque of permanent-magnet synchronous machines several approaches are known. But cogging torque predictions for arbitrary types of machines using the same approach are still troublesome and imprecise. Therefore, a fast optimization process is developed and presented in this paper. Here, the combination of both numerical and analytical simulation results in such a fast method}, language = {en} } @article{JacobsHectorsHenrotteetal., author = {Jacobs, Sigrid and Hectors, Dietrich and Henrotte, Fran{\c{c}}ois and Hafner, Martin and Herranz Gracia, Mercedes and Hameyer, Kay and Goes, Patrick}, title = {Magnetic material optimization for hybrid vehicle PMSM drives}, series = {World Electric Vehicle Journal}, volume = {3}, journal = {World Electric Vehicle Journal}, number = {4}, issn = {2032-6653}, doi = {10.3390/wevj3040875}, pages = {875 -- 883}, abstract = {The motivation of this analysis is the need of high efficiency and high power density permanent magnet synchronous motor (PMSM) drives for use in electrical vehicle power trains. It is clear that the chosen electrical steel for the lamination stack plays an important role, but proper quantification is missing. The purpose of this paper is to formalize the problem of selecting the optimal steel grade for the construction of PMSM's. This question is important to steel producers, not only for helping customers selecting the most appropriate existing grade for their application, but also for defining the strategic orientation of the further R\&D of enhanced electrical steel grades. The notion of steel efficiency is defined and, after describing the FE implementation of iron loss models, a methodology for material optimisation is proposed.}, language = {en} } @article{CoenenHerranzGraciaHameyer, author = {Coenen, Isabel and Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Influence and evaluation of non-ideal manufacturing process on the cogging torque of a permanent magnet excited synchronous machine}, series = {COMPEL-The international journal for computation and mathematics in electrical and electronic engineering}, volume = {30}, journal = {COMPEL-The international journal for computation and mathematics in electrical and electronic engineering}, number = {3}, doi = {10.1108/03321641111110843}, abstract = {Purpose - The purpose of this paper is to describe how a minimisation of cogging torque is performed with respect to the non-ideal manufacturing process, aiming at a robust design of the studied machine, focusing on magnetisation faults and the use of different qualities of the permanent magnet material. Design/methodology/approach - The applied methodology is a combination of design of experiments and finite element analysis to minimise the cogging torque of the estimated machine. Different qualities of the permanent magnet material are investigated by a stochastic analysis. Findings - A robust design of the machine is achieved, which is verified by a stochastic analysis. Furthermore, this analysis shows the strong influence of the magnet quality on the cogging torque. Practical implications - This paper provides a method for a machine design which is robust against non-ideal manufacturing and an approach to prove the use of a bad quality for a possible reduction of the fabrication costs. Originality/value - This paper gives a close insight on how to investigate non-ideal manufacturing and in particular its influence on the cogging torque.}, language = {en} } @article{SteffenLengsfeldJungetal., author = {Steffen, Jonas and Lengsfeld, Sebastian and Jung, Marco and Ponick, Bernd and Herranz Gracia, Mercedes and Spagnolo, Aristide and Kl{\"o}pzig, Markus and Schleicher, Klaus and Sch{\"a}fer, Klaus}, title = {Design of a Medium Voltage Generator with DC-Cascade for High Power Wind Energy Conversion Systems}, series = {Energies}, volume = {14}, journal = {Energies}, number = {11}, issn = {1996-1073}, doi = {10.3390/en14113106}, abstract = {This paper shows a new concept to generate medium voltage (MV) in wind power application to avoid an additional transformer. Therefore, the generator must be redesigned with additional constraints and a new topology for the power rectifier system by using multiple low voltage (LV) power rectifiers connected in series and parallel to increase the DC output voltage. The combination of parallel and series connection of rectifiers is further introduced as DC-cascade. With the resulting DC-cascade, medium output voltage is achieved with low voltage rectifiers and without a bulky transformer. This approach to form a DC-cascade reduces the effort required to achieve medium DC voltage with a simple rectifier system. In this context, a suitable DC-cascade control was presented and verified with a laboratory test setup. A gearless synchronous generator, which is highly segmented so that each segment can be connected to its own power rectifier, is investigated. Due to the mixed AC and DC voltage given by the DC-cascade structure, it becomes more demanding to the design of the generator insulation, which influences the copper fill factor and the design of the cooling system. A design strategy for the overall generator design is carried out considering the new boundary conditions.}, language = {en} } @article{FilipenkoKuehnGleixneretal., author = {Filipenko, Mykhaylo and K{\"u}hn, Lars and Gleixner, Thomas and Thummet, Martin and Lessmann, Marc and M{\"o}ller, Dirk and B{\"o}hm, Matthias and Schr{\"o}ter, Andreas and H{\"a}se, Kerstin and Grundmann, J{\"o}rn and Herranz Gracia, Mercedes}, title = {Concept design of a high power superconducting generator for future hybrid-electric aircraft}, series = {Superconductor Science and Technology}, volume = {33}, journal = {Superconductor Science and Technology}, number = {5}, doi = {10.1088/1361-6668/ab695a}, pages = {054002 -- 054002}, abstract = {he reduction of emission is a key goals for the aviation industry. One enabling technology to achieve this goal, could be the transition from conventional gas turbines to hybrid-electric drive trains. However, the requirements concerning weight and efficiency that come from applications like short range aircraft are significantly higher than what state-of-the-art technology can offer. A key technology that potentially allows to achieve the necessary power and volume densities for rotating electric machines is superconductivity. In this paper we present the concept of a high power density generator that matches the speed of typical airborne turbines in its power class. The design is based on studies that cover topology selection and further electromagnetic, HTS, thermal, structural and cryogenics aspects. All domains were analyzed by means of analytical sizing and 2D/3D FEA modeling. With the help of our digital twin that is a synthesis of these models, we can demonstrate for the first time that under realistic assumptions on material properties gravimetric power densities beyond 20 kW kg-1 can be achieved.}, language = {en} } @inproceedings{SchlensokHerranzGraciaHameyer, author = {Schlensok, Christoph and Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Structure-Dynamic Simulation of an Induction Maschine with Eccentrically Positioned Squirrel-Cage Rotor}, series = {XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ISEF}, booktitle = {XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ISEF}, language = {en} } @inproceedings{SchlensokHerranzGraciaHameyer, author = {Schlensok, Christoph and Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Combined Numerical and Analytical Method for a Geometry Optimization of a PM Motor}, series = {16th International Conference on the Computation of Electromagnetic Fields, COMPUMAG}, booktitle = {16th International Conference on the Computation of Electromagnetic Fields, COMPUMAG}, language = {en} } @inproceedings{HerranzGraciaHameyer, author = {Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Comparison of 2D Simulation and analytical calculation of the short-circuit behaviour of a permanent-magnet synchronous machine}, series = {XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ISEF}, booktitle = {XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ISEF}, language = {en} } @inproceedings{vanderGietRotheHerranzGraciaetal., author = {van der Giet, Michael and Rothe, R. and Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Analysis of noise exciting magnetic force waves by means of numerical simulation and a space vector definition}, series = {XVIII International Conference on Electrical Machines, ICEM}, booktitle = {XVIII International Conference on Electrical Machines, ICEM}, language = {en} } @inproceedings{HerranzGraciaHameyer, author = {Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Effect of non-sinusoidal currents on the acoustic noise excitation of induction motors}, series = {13th IGTE Symposium}, booktitle = {13th IGTE Symposium}, language = {en} } @inproceedings{HerranzGraciaHameyer, author = {Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Comparision of numerical methods for the prediction of cogging torque in 2D and 3D}, series = {13th IGTE Symposium}, booktitle = {13th IGTE Symposium}, language = {en} } @inproceedings{JonasLengsfeldJungetal., author = {Jonas, Steffen and Lengsfeld, Sebastian and Jung, Marco and Ponick, Bernd and Herranz Gracia, Mercedes and Spagnolo, Aristide and Schleicher, Klaus, and Sch{\"a}fer, Klaus}, title = {Design of a Medium Voltage Generator and Power Converter for High Power Wind Energy Conversion Systems}, series = {2020 55th International Universities Power Engineering Conference (UPEC)}, booktitle = {2020 55th International Universities Power Engineering Conference (UPEC)}, doi = {10.1109/UPEC49904.2020.9209886}, pages = {1 -- 5}, language = {en} } @article{HerranzGraciaHameyer, author = {Herranz Gracia, Mercedes and Hameyer, Kay}, title = {Influence of the magnetic anisotropy on electrical machines}, series = {Advanced Computer Techniques in Applied Electromagnetics - Studies in Applied Electromagnetics and Mechanics}, volume = {30}, journal = {Advanced Computer Techniques in Applied Electromagnetics - Studies in Applied Electromagnetics and Mechanics}, doi = {10.3233/978-1-58603-895-3-39}, pages = {39 -- 46}, abstract = {Non grain-oriented electrical steel has an inherent anisotropy, which is normally neglected in the calculation of electrical machines. Moreover, the magnetic anisotropy is usually measured in small material samples. Due to the cutting effect, the magnetic anisotropy in the machine is not the same as in the sample. In this paper, the magnetic anisotropy is considered as a global problem. A method to measure it is presented and its influence on the electromagnetic and acoustic behavior is considered through the example of an induction motor.}, language = {en} } @article{HafnerHenrotteHerranzGraciaetal., author = {Hafner, Martin and Henrotte, Francois and Herranz Gracia, Mercedes and Hameyer, Kay}, title = {An Energy-Based Harmonic Constitutive Law for Magnetic Cores With Hysteresis}, series = {IEEE Transactions on Magnetics}, volume = {44}, journal = {IEEE Transactions on Magnetics}, number = {6}, publisher = {IEEE}, doi = {10.1109/TMAG.2007.916141}, pages = {922 -- 925}, abstract = {In this paper, a phenomenological energy-based material model for ferromagnetic materials under harmonic conditions is presented. The model is based on the concept of a complex effective permeability and an accurate representation of energy is adopted as identification criteria. The material model is implemented in a time-harmonic finite element model, which allows to solve for the loss characteristics of electromagnetic devices. Identification is based on measured hysteresis loops and no additional fitting parameters are required. Hysteresis losses in a ferromagnetic C-core and a ferromagnetic torus are simulated and compared to the results obtained by means of tabulated loss characteristics.}, language = {en} } @inproceedings{MuellerHeilmannHerranzGraciaetal., author = {M{\"u}ller, Marcel and Heilmann, Marcel and Herranz Gracia, Mercedes and Kempkes, Joachim and H{\"a}fner, Martin and Becher, Manuel}, title = {Consideration of the influence of manufacturing tolerances in the design process of electrical machines using the example of a permanent magnet synchronous machine}, editor = {Forschungsvereinigung Antriebstechnik e.V.,}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-47594}, pages = {8}, abstract = {The production process of electrical machines is subject to manufacturing and material tolerances. These tolerances have an influence on both, the mean torque and the torque ripple. Consequently, they exert an active influence on the speed-torque map (operating points), as well as the equivalent circuit diagram parameters for a permanent magnet synchronous machine, and the operational behavior (efficiency, noise development) of the electrical machine. In addition to striving lower costs, there is a growing emphasis on achieving higher energy efficiency. Thus, an accurate prediction of machine parameters is still essential during the early development process, despite manufacturing-related deviations. In this study, the prediction of machine parameters is demonstrated using the example of a PMSM.}, language = {en} } @inproceedings{SchulerHerranzGraciaKempkesetal., author = {Schuler, Max and Herranz Gracia, Mercedes and Kempkes, Joachim and Heilmann, Marcel}, title = {PyEMMO - a Python based software for the finite element modelling of electrical machines in ONELAB}, series = {15. International conference on electric vehicle drives and e-mobility}, booktitle = {15. International conference on electric vehicle drives and e-mobility}, editor = {Forschungsvereinigung Antriebstechnik e.V.,}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-55489}, pages = {179-184}, abstract = {Multi-objective optimizations are almost essential in the design process of electrical machines due to constantly increasing requirements for efficiency and power density. In this context, open-source simulation software offers the possibility to parallelize calculations free of license costs and thus to achieve a reduced calculation time. This paper presents the software project PyEMMO (Python Electrical Machine Modeling in ONELAB) for the finite element simulation of electrical machines in the open source program ONELAB. The object-oriented program structure and the objectives of the project are the main focus. Furthermore, the latest features are discussed, which include the geometry definition via a toolbox system, the simulation data interface based on the JSON file format and the calculation of iron losses.}, language = {de} } @inproceedings{HeilmannSteckelSchuleretal., author = {Heilmann, Marcel Norbert and Steckel, Richard and Schuler, Max and Keller, Daniel and Gracia, Mercedes Herranz and Kempkes, Joachim}, title = {Improved Calculation of the Force Density in the Air Gap of a Squirrel Cage Induction Machine for NVH Simulation}, series = {2024 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM)}, booktitle = {2024 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM)}, publisher = {IEEE}, doi = {10.1109/SPEEDAM61530.2024.10609211}, pages = {812 -- 818}, language = {en} }