@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} }