In this paper, a detailed methodology for the design and characterization of cooling systems oriented to electrical machines is presented. Different kinds of tools such as lumped-parameter models and computational fluid dynamics (CFD) simulations are combined all together in order to achieve accurate designs with reduced time consumptions. It is well known that CFD simulations can be very arduous and they can take too much time. In order to work out these drawbacks, in this work, several procedures to analyze electrical machines by CFD simulations are described in detail. For instance, it is described how to simulate fans or how to design a cooling system using CFD simulations. Finally, the proposed design methodology has been implemented in a real case study, designing the air cooling system for a permanent-magnet synchronous machine. Then, a prototype has been built in order to validate the methodology and the different design tools. The experimental results have a very good agreement with the expected ones.

This paper deals with the development of analysis tools for axial-flux permanent-magnet machines. Normally, the study of this kind of machine involves three-dimensional (3-D) finite element method (FEM) (FEM-3-D) due to the 3-D nature of the magnetic problem. As it is widely known, the FEM-3-D software could take too much time, and both definition and solving processes of the problem may be very arduous. In this paper, a novel analysis procedure for axial-flux synchronous machines is proposed. This method consists in the combination of 2-D FEM simulations with analytical models based on the Fourier-series theory. The obtained results prove that the proposed method could be a very interesting option in terms of time and accuracy.

This document reviews the current state of the art in the linear machine technology. First, the recent advancements in linear induction, switched reluctance and permanent magnet machines are presented. The ladder slit secondary configuration is identified as an interesting configuration for linear induction machines. In the case of switched reluctance machines, the mutually-coupled configuration has been found to equate the thrust capability of conventional permanent magnet machines. The capabilities of the so called linear primary permanent magnet, viz. switched-flux, flux-reversal, doubly-salient and vernier machines are presented afterwards. A guide of different options to enhance several characteristics of linear machines is also listed. A qualitative comparison of the capabilities of linear primary permanent magnet machines is given later, where linear vernier and switched-flux machines are identified as the most interesting configurations for long stroke applications. In order to demonstrate the validity of the presented comparison, three machines are selected from the literature, and their capabilities are compared under the same conditions to a conventional linear permanent magnet machine. It is found that the flux-reversal machines suffer from a very poor power factor, whereas the thrust capability of both vernier and switchedflux machines is confirmed. However, the overload capability of these machines is found to be substantially lower than the one from the conventional machine. Finally, some different research topics are identified and suggested for each type of machine.

The design of Synchronous Reluctance Motor (SynRM) has a lot of variables. There are some difficulties to design proper rotor-flux barrier geometry. It is necessary obtain an optimized geometry to get the satisfactory results of torque ripple, average torque, etc. SynRM is a new motor topology but in electrical railway applications is not working yet. The mature topology in this application is Induction Motor (IM). The main contribution of this paper is to compare both motors and obtain an answer about if we can use SynRM in electrical railway applications replacing IM and whose are advantages and disadvantages of this topology in the application. To compare both topologies we select a traction IM and its performances to design a SynRM that get the same ones. The comparison has been carried out on finite-elements analysis (electromagnetic and thermal analysis) of SynRM.

Nowadays, many applications are demanding more and more compact, cost effective and robust electric drives. By using rare earth magnets, it is possible to achieve electrical machines with rather high torque volume ratio, accomplishing this way the compactness requirement. Nevertheless, rare earth permanent magnets are very sensitive to the temperature, so that the risk of being partially demagnetized arises as their working temperature increases. In addition, as it has been seen during the last years, the market of rare earth metals is quite volatile. The price of magnets could rise suddenly, leading to a significant impact on the cost, and so in the competitiveness of Permanent Magnet Machines. Due to this fact, it is essential to reduce the dependency on rare earth market in order to accomplish cost effective drive solutions. Some key points to face this problem can be to reduce the magnet volume, or to use magnets with worse thermal properties (magnets with less dysprosium). Nevertheless, in both cases, the adopted solution would lead to an increase in the risk of demagnetization, affecting to the robustness of the machine. In this paper, a methodology based on Finite Element Analysis and experimental test is proposed to evaluate the demagnetization risk in Permanent Magnet Machines. By applying this methodology, it is possible to accomplish competitive machine designs, achieving a good trade-off between cost and robustness. The proposed methodology has been applied in a practical case, for the optimization of 10 industrial motors, achieving good results.