Ana Julia Escalada

Axial-Flux-Machine Modeling With the Combination of FEM-2-D and Analytical Tools

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.

Thermal test procedure and analytical model calibration method for electrical machines

In this paper a thermal test procedure and a calibration method for lumped parameter models are presented. Analytical models provide fast thermal simulations in comparison with finite element methods (FEM) and computed fluid dynamics (CFD) simulations. Motor-CAD is a useful and easy configurable tool to simulate motor models, but the quantity of construction parameters makes difficult the calibration process of a model. This paper provides a thermal test process to test machines to calibrate analytical models. And the procedure to estimate temperatures and calculate their uncertainties is exposed. Also a calibration method is proposed to identify critical parameters on analytical models that determine thermal behaviour of the machine. Specific thermal test are designed in order to calibrate these critical parameters like the base in the test bench. Finally the calibration process is validated with 3 different but similar machines. The same analytic model with only construction differences satisfies experimental thermal tests of 3 machines.

Extended DQ model of a Permanent Magnet Synchronous Machine by including magnetic saturation and torque ripple effects

Nowadays the comfort in passenger transport system is very relevant. One source of noise and vibration is the torque ripple. Torque ripple can be generated by an inappropriate machine control tuning and by the inherent torque ripple of the machine. In permanent magnet machines, the inherent torque ripple is composed by three components: electromagnetic torque, reluctant torque, caused by the winding magnetic field, and reluctant torque caused by the permanent magnet magnetic field, commonly known as cogging torque. In order to assess the torque ripple at each working point, the electromagnetic analysis using a Finite Element Method (FEM) is a very accurate solution. In a dynamic simulation the high computational load is the main drawback of the FEM analysis. To overcome this problem, in this paper the use of a mixed approach is proposed, in which the parameters of a dynamic vector model are previously adjusted using FEM characterization. The aim of this strategy is to do just one complex FEM simulation, so later a quicker dynamic model can be used. In this article, an adjusted dynamic vector model of a Permanent Magnet Synchronous Machine (PMSM) is presented. The inputs of the model are the phase voltages and the rotor position. The outputs are the currents, the flux linkages and the total electromagnetic torque, including all the parasitic components of the torque ripple. The advantages of this model are the reduction of simulation time and the possibility to integrate it in a more general dynamic simulation platform.

Analytical model to calculate radial forces in permanent-magnet synchronous machines

In permanent-magnet synchronous machines (PMSMs) electromagnetic forces are identified as the principal source of vibrations and noises. In this article, first of all the sources of magnetic forces in PMSMs are analyzed. Then, an analytical method for the calculation of radial forces on the base of the stator tooth created by electromagnetic sources in PMSMs is presented. Finally finite element method (FEM) is used to corroborate analytical results.

Matlab-Simulink Coupling to Finite Element Software for Design and Analysis of Electrical Machines

© 2012 Almandoz et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Matlab-Simulink Coupling to Finite Element Software for Design and Analysis of Electrical Machines

Equivalent Circuit of a Linear Induction Motor with Variable Parameters

Nowadays linear induction motors (LIM) are used in many industrial applications. The simulation of electrical machine is essential to optimise the design processes and control systems. There is a need of mathematical models of LIMs capable of predicting their performance. In this paper, the experimental characterization of a LIM prototype is presented, which is based on an equivalent circuit with variable parameters

Methodology to study demagnetization risk in permanent magnet machines by Finite Element Method

Nowadays the majority of applications are demanding more and more compact, cost effective and robust solutions for their electric drives. In this context permanent magnet synchronous machines are considered as a good candidate due to their high torque density. This torque density is obtained thanks to high power rare earth magnets with both high remanence and high coercive force. However, the magnets cost has a relevant impact in the final cost of the electrical machine and the uncertainty shown by the rare earth market in the last years has originated high variations in the price of them. Due to that, it is essential to reduce this impact in order to accomplish cost effective drive solutions. Some key points to face this problem are the reduction of the magnets volume or the using of magnets with worse thermal properties (magnets with few dysprosium and with low coercive force). In both cases special attention must be paid on the demagnetization risk of the magnets. To carry out that analysis, in this article a finite element method simulation analysis process for demagnetization of permanent magnets is presented. The developed method has been validated experimentally in a test bench. Good agreement is shown between simulations and experimental results.

Analytical model to calculate magnetic flux density in permanent magnet synchronous machines with static eccentricity

In this article a general analytical model for the analysis of permanent magnet synchronous machines with static eccentricity is presented. The model is a continuation of [1] and it is based on Fourier time-space series formulated in 2-D coordinates. The results of the model are corroborated by simulations of finite element method over two different machines. The results of the model show a good agreement with the results obtained from simulations.

Numerical 2D methodology for synchronous reluctance motor rotor design

In this work a design methodology for synchronous reluctance motors (SynRM) is presented. The methodology is focused on maximizing the average torque but also takes into account the torque ripple. The presented methodology parameterizes the rotor in function of certain design variables which define the arrangement of the iron segments and flux barriers. The change in one of these design variables involves a change in the rotor geometry, resulting in a new machine design. The methodology is based in the systematically change of the design variables. The machine electromagnetic behavior and the performance of the motor is evaluated with finite elements models (FEM).

Radial fan simulations by computational fluid dynamics and experimental validation

Fans are commonly used to refrigerate electrical machines when air forced cooling is required. They are rather simple solutions that can considerably improve the thermal performance of electrical machines, so the fan analysis could become an important point during the thermal design of electrical machines. This paper presents an analysis by computational fluid dynamics (CFD) simulations with the goal of characterizing radial fans, used in electrical machines. Different boundary conditions and parameters that affect to CFD results are evaluated in order to get an efficient way to simulate radial fans. The main objective is to obtain the flow-pressure characteristic curve of fans and airflow velocities by CFD simulations. Finally CFD simulation results of 2 fans are experimentally validated. One of them has been analysed in a fan testing wind tunnel. And the second one has been analysed in an auto-ventilated machine.