TY - CHAP A1 - Herranz Gracia, Mercedes A1 - Hameyer, Kay T1 - Influence of the magnetic anisotropy on electrical machines T2 - XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ISEF N2 - 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. Y1 - 2007 UR - http://bib.iem.rwth-aachen.de/IEMpublications/AltesBib/2008MHGInfluence.pdf ER - TY - CHAP A1 - Herranz Gracia, Mercedes A1 - Lange, E. A1 - Hameyer, Kay T1 - Numerical Calculation of Iron Losses in Electrical Machines with a modified Post-Processing Formula T2 - 16th International Conference on the Computation of Electromagnetic Fields, COMPUMAG Y1 - 2007 UR - http://bib.iem.rwth-aachen.de/IEMpublications/AltesBib/2007MHGModified.pdf ER - TY - CHAP A1 - Herranz Gracia, Mercedes A1 - Hameyer, Kay T1 - Study of Temperature Rise Problems of Stepper Motors under High Duty Cycle T2 - 42nd International Symposium on Electrical Machines, SME Y1 - 2006 ER - TY - JOUR A1 - Schlensok, Christoph A1 - van der Giet, Michael A1 - Herranz Gracia, Mercedes A1 - van Riesen, Dirk A1 - Hameyer, Kay T1 - Structure-Dynamic Analysis of an Induction Machine Depending on Stator-Housing Coupling JF - IEEE Transactions on Industry Applications N2 - 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. KW - asynchronous machines KW - finite element analysis KW - vibrationselectric machinery KW - induction machine KW - spiral-steel springs KW - stator-housing coupling KW - structure-dynamic analysis Y1 - 2008 U6 - https://doi.org/10.1109/TIA.2008.921440 SN - 0093-9994 VL - 44 IS - 3 SP - 753 EP - 759 ER - TY - JOUR A1 - Schlensok, Christoph A1 - Herranz Gracia, Mercedes A1 - Hameyer, Kay T1 - Combined Numerical and Analytical Method for Geometry Optimization of a PM Motor JF - IEEE Transactions on Magnetics N2 - 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 Y1 - 2006 UR - http://bib.iem.rwth-aachen.de/IEMpublications/AltesBib/2006CSCombined.pdf U6 - https://doi.org/10.1109/TMAG.2006.871379 VL - 42 IS - 4 SP - 1211 EP - 1214 PB - IEEE ER - TY - JOUR A1 - Jacobs, Sigrid A1 - Hectors, Dietrich A1 - Henrotte, François A1 - Hafner, Martin A1 - Herranz Gracia, Mercedes A1 - Hameyer, Kay A1 - Goes, Patrick T1 - Magnetic material optimization for hybrid vehicle PMSM drives JF - World Electric Vehicle Journal N2 - 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. Y1 - 2009 U6 - https://doi.org/10.3390/wevj3040875 SN - 2032-6653 VL - 3 IS - 4 SP - 875 EP - 883 ER - TY - JOUR A1 - Coenen, Isabel A1 - Herranz Gracia, Mercedes A1 - Hameyer, Kay T1 - Influence and evaluation of non-ideal manufacturing process on the cogging torque of a permanent magnet excited synchronous machine JF - COMPEL-The international journal for computation and mathematics in electrical and electronic engineering N2 - 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. Y1 - 2011 U6 - https://doi.org/10.1108/03321641111110843 VL - 30 IS - 3 ER - TY - JOUR A1 - Steffen, Jonas A1 - Lengsfeld, Sebastian A1 - Jung, Marco A1 - Ponick, Bernd A1 - Herranz Gracia, Mercedes A1 - Spagnolo, Aristide A1 - Klöpzig, Markus A1 - Schleicher, Klaus A1 - Schäfer, Klaus T1 - Design of a Medium Voltage Generator with DC-Cascade for High Power Wind Energy Conversion Systems JF - Energies N2 - 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. Y1 - 2021 U6 - https://doi.org/10.3390/en14113106 SN - 1996-1073 VL - 14 IS - 11 ER - TY - JOUR A1 - Filipenko, Mykhaylo A1 - Kühn, Lars A1 - Gleixner, Thomas A1 - Thummet, Martin A1 - Lessmann, Marc A1 - Möller, Dirk A1 - Böhm, Matthias A1 - Schröter, Andreas A1 - Häse, Kerstin A1 - Grundmann, Jörn A1 - Herranz Gracia, Mercedes T1 - Concept design of a high power superconducting generator for future hybrid-electric aircraft JF - Superconductor Science and Technology N2 - 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. Y1 - 2020 U6 - https://doi.org/10.1088/1361-6668/ab695a VL - 33 IS - 5 SP - 054002 EP - 054002 ER - TY - CHAP A1 - Schlensok, Christoph A1 - Herranz Gracia, Mercedes A1 - Hameyer, Kay T1 - Structure-Dynamic Simulation of an Induction Maschine with Eccentrically Positioned Squirrel-Cage Rotor T2 - XIII International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ISEF Y1 - 2005 UR - https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7414475 ER -