Martin Marco Nell, Benedikt Groschup and Kay Hameyer
This paper aims to use a scaling approach to scale the solutions of a beforehand-simulated finite element (FE) solution of an induction machine (IM). The scaling procedure is…
Abstract
Purpose
This paper aims to use a scaling approach to scale the solutions of a beforehand-simulated finite element (FE) solution of an induction machine (IM). The scaling procedure is coupled to an analytic three-node-lumped parameter thermal network (LPTN) model enabling the possibility to adjust the machine losses in the simulation to the actual calculated temperature.
Design/methodology/approach
The proposed scaling procedure of IMs allows the possibility to scale the solutions, particularly the losses, of a beforehand-performed FE simulation owing to temperature changes and therefore enables the possibility of a very general multiphysics approach by coupling the FE simulation results of the IM to a thermal model in a very fast and efficient way. The thermal capacities and resistances of the three-node thermal network model are parameterized by analytical formulations and an optimization procedure. For the parameterization of the model, temperature measurements of the IM operated in the 30-min short-time mode are used.
Findings
This approach allows an efficient calculation of the machine temperature under consideration of temperature-dependent losses. Using the proposed scaling procedure, the time to simulate the thermal behavior of an IM in a continuous operation mode is less than 5 s. The scaling procedure of IMs enables a rapid calculation of the thermal behavior using FE simulation data.
Originality/value
The approach uses a scaling procedure for the FE solutions of IMs, which results in the possibility to weakly couple a finite element method model and a LPTN model in a very efficient way.
Details
Keywords
Jan Karthaus, Benedikt Groschup, Robin Krüger and Kay Hameyer
Due to the increasing amount of high power density high-speed electrical machines, a detailed understanding of the consequences for the machine’s operational behaviour and…
Abstract
Purpose
Due to the increasing amount of high power density high-speed electrical machines, a detailed understanding of the consequences for the machine’s operational behaviour and efficiency is necessary. Magnetic materials are prone to mechanical stress. Therefore, this paper aims to study the relation between the local mechanical stress distribution and magnetic properties such as magnetic flux density and iron losses.
Design/methodology/approach
In this paper, different approaches for equivalent mechanical stress criteria are analysed with focus on their applicability in electrical machines. Resulting machine characteristics such as magnetic flux density distribution or iron are compared.
Findings
The study shows a strong influence on the magnetic flux density distribution when considering the magneto-elastic effect for all analysed models. The influence on the iron loss is smaller due to a high amount of stress-independent eddy current loss component.
Originality/value
The understanding of the influence of mechanical stress on dimensions of electrical machines is important to obtain an accurate machine design. In this paper, the discussion on different equivalent stress approaches allows a new perspective for considering the magneto-elastic effect.
Details
Keywords
Benedikt Groschup, Silas Elfgen and Kay Hameyer
The cutting process of the electric machine laminations causes residual mechanical stress in the soft magnetic material. A local magnetic deterioration can be observed and the…
Abstract
Purpose
The cutting process of the electric machine laminations causes residual mechanical stress in the soft magnetic material. A local magnetic deterioration can be observed and the resulting local and global iron losses increase. A continuous local material model for the consideration of the changing magnetization properties has been introduced in a previous work as well as an a priori assessment of iron losses. A local iron loss calculation considering both a local magnetization and local loss parameters misses yet. The purpose of this study is to introduce a local iron loss calculation model considering both a local magnetization and local loss parameters.
Design/methodology/approach
In this paper, an approach for local iron loss simulation is developed and a comparison to the cut-edge length-dependent loss model is given. The comparison includes local loss distribution in the lamination as well as the impact on the overall motor efficiency and vehicle range in an electric vehicle driving cycle.
Findings
For an analysis of the resulting local iron loss components, both the local magnetization and iron loss parameters must be considered using physically based models. Consistently, a local iron loss model is presented in the work. The developed model can be used to gain detailed information of the local loss distribution inside the machine. The comparability of this local iron loss with the cut-edge length approach for overall system characteristics, e.g. efficiency or driving range, is shown.
Originality/value
A local iron loss simulation approach is a physical accurate model to describe the influence of cutting techniques on electric machine characteristics. A comparison with the less complicated a priori assessment gives detailed information about the necessity of the local model under consideration of the given problem.
Details
Keywords
Andrzej Demenko, Kay Hameyer, Jean-Philippe Lecointe, Ewa Napieralska-Juszczak and Wojciech Pietrowski