The different levels of magneto-mechanical coupling in energy conversion machines and devices

This paper reviews the methods for coupling the magnetic and mechanical problems in magnetic materials and their application to electrical machines. The reviewed methods include both the material models and the computing methods as well as the methods for computing the magnetic forces. The paper shows that there are different levels of coupling the magnetic system with the mechanical one and that the use of a method or another depends on the application and the level of accuracy aimed at. The paper also clarifies some terms and concepts related to the coupling terminology such as strong, weak, local, global, direct and indirect coupling and put these terms in a coherent context. Most of the examples are related to the two dimensional analysis but some three dimensional ones are also shown

Air-gap force distribution and vibration pattern of Induction motors under dynamic eccentricity

[EN] A method for determining the signatures of dynamic eccentricity in the airgap force distribution and vibration pattern of induction machine is presented. The radial electromagnetic force distribution along the airgap, which is the main source of vibration, is calculated and developed into a double Fourier series in space and time. Finite element simulations of faulty and healthy machines are performed. They show that the electromagnetic force distribution is a sensible parameter to the changes in the machine condition. The computations show the existence of low frequency and low order force distributions, which can be used as identifiable signatures of the motor condition by measuring the corresponding low order vibration components. These findings are supported by vibration measurements and modal testing. The low frequency components offer an alternative way to the monitoring of slot passing frequencies, bringing new components that allow to discriminate between dynamic eccentricity and rotor mechanical unbalance. The method also revealed a non linear relationship between loading, stress waves and vibration during dynamic eccentricity.Jover Rodríguez, PV.; Belahcen, A.; Arkkio, A.; Laiho, A.; Antonino-Daviu, J. (2008). Air-gap force distribution and vibration pattern of Induction motors under dynamic eccentricity. Electrical Engineering. 90(3):209-218. doi:10.1007/s00202-007-0066-2S209218903Rao JS (2000). Vibratory condition monitoring of machines. CRC Pr. Llc., Boca RatonTavner P, Penman J (1987) Condition monitoring of electrical machines. Research Studies Press, Letchworth, pp 203–205Pöyhönen S, Negrea M, Jover P, Arkkio A and Hyötyniemi H (2003). Numerical magnetic field analysis and signal processing for fault diagnostic of electrical machines. COMPEL Int J Comput Math Elect Eng 22(4): 969–981Finley W, Hodowanec M, Holter W (2000) An analytical approach to solving motor vibration problems. IEEE Trans Industry Appl 363(5)Cameron JR, Thomson WT, Eng C, Dow AB (1986) Vibration and current monitoring for detecting airgap eccentricity in large induction motors. IEE Proc Inst Elect Eng 133(Pt. B, No. 3)Smith AC, Dorrell DG (1996) Calculation and measurements of unbalance magnetic pull in cage induction motors with eccentric rotors. Part 1: Analytical model. IEE Proc Elect Power Appl 143(3)Dorrell DG, Smith AC (1996) Calculation and measurements of unbalance magnetic pull in cage induction motors with eccentric rotors. Part 2: Experimental investigation. IEE Proc Elect Power Appl 143(3)Dorrell DG, Thomson WT and Roach S (1997). Analysis of airgap flux, current, and vibration signals as a function of a combination of static and dynamic eccentricity in 3-phase induction motors. IEEE Trans Indus Appl 33: 24–34Verma SP, Balan A (1994) Determination of radial forces in relation to noise and vibrations problems of squirrel cage induction motors. IEEE Trans Energy Convers 9(2)Vandevelde L, Melkebeek AA (2001) Numerical analysis of vibrations of squirrel-cage induction motors based on magnetic equivalent circuits and structural finite element models. In: Industry Application Conference, 2001. Thirsty-six IAS Annual Meeting. Conference records of the 2001 IEEE, vol 4, September/October 2001, pp 2288–2295Belahcen A, Arkkio A, Klinge P, Linjama J, Voutilainen V, Westerlund J (1999) Radial forces calculation in a synchronous generator for noise analysis. In: Proceeding of the Third Chinese International Conference on Electrical Machines, August 29–31, 1999, Xi’an, China, pp 199–122Jover Rodríguez P, Belahcen A, Arkkio A (2007) Signatures of electrical faults in force distribution and vibration pattern of induction motors. IEE Proc Elect Power Appl (in press)Arkkio A (1987) Analysis of induction motor based on numerical solution of the magnetic field and circuits equations. Acta Polytechn. Scand Electri Eng Serie 59:97. Available at  Ewings DG (2000). MODAL TESTING: theory, practice and application, 2nd edn. Research studies press Ltd., BaldockDeBertoli MJ, Salon SJ, Burow DW, Slavik CJ (1993) Effects of rotor eccentricity and parallel windings on induction machine behaviour: a study using finite element analysis. IEEE Trans Magnet 29(2)Arkkio A, Antila M, Pokki K, Lanto E (2000) Electromagnetic force in a whirling cage rotor. IEE Proc Elect Power Appl 147(5

Investigation of six-phase surface permanent magnet machine with typical slot/pole combinations for integrated onboard chargers through methodical design optimization

This article presents an analytical magnetic equivalent circuit (MEC) modeling approach for a six-phase surface-mounted permanent magnet (SPM) machine equipped with fractional slot concentrated winding (FSCW) for integrated onboard chargers. For the sake of comparison, the selected asymmetrical six-phase slot/pole combinations with the same design specifications and constraints are first designed based on the parametric MEC model and then optimized using a multiobjective genetic algorithm (MOGA). The commercial BMW i3 design specifications are adopted in this article. The main focus of this study is to achieve optimal design of the SPM machine considering both the propulsion and charging performances. Thus, a comparative study of the optimization cost functions, including the peak-to-peak torque ripple and core losses under both motoring and charging modes and electromagnetic forces (EMFs) under charging, is conducted. In addition, the demagnetization capability in the charging mode and the overall cost of the employed machines are optimized. Since the average propulsion torque is crucial in electric vehicle (EV) applications, it is maintained through the design optimization process. Furthermore, finite element (FE) simulations have been carried out to verify the results obtained from the analytical MEC model. Eventually, the effectiveness of the proposed design optimization process is corroborated by experimental tests on a 2-kW prototype system

Coupled wave-equation and eddy-current model for modelling and measuring propagating stress-waves

The coupling of the propagating stress wave with the eddy current model is presented. The applied stress produces magnetization in the sample that can be measured outside the sample by measuring the resulting magnetic flux density. The stress and flux density measurements are made on a mechanically excited steel bar. The problem is modelled with the finite element method for both the propagating wave and the eddy current. Three aspects are considered: eddy current model using magnetization from the measurements, coupled wave and eddy current models, and coupled different dimensions in the wave model. The measured stress can be reproduced from the measured flux density by modelling. The coupled models work both for stress and flux couplings as well as for the different dimensionality couplings

A High-Performance Open-Source Finite Element Analysis Library for Magnetics in MATLAB

| openaire: EC/FP7/339380/EU//ALEMTwo-dimensional finite element analysis is a widely used tool in the design, analysis, and optimization of electrical machines and magnetic components. Although the core components of the method are relatively mature, numerous special applications are still being developed. This paper introduces an open-source library for finite element analysis in Matlab, tailored especially for electrical machines. The library is highly portable, and has a good performance. Furthermore, it provides all the basic functionality typically needed for magnetic analysis. As such, it can be used as a starting point for more advanced work.Peer reviewe

Carbon Fiber Homogenization for Modelling Sleeve of High-Speed Electrical Machines

Publisher Copyright: © 2022 IEEE.At present, carbon fiber has become widespread and used in electromechanical technologies in the development of processing technologies. However, when modeling carbon fiber, difficulties arise-often, the mechanical parameters of separately carbon fiber and epoxy resin are known, and only for a specific layer thickness. Also, carbon fiber is used as a composite material, and, therefore, there is a need to determine the optimal sequence of sheet orientation for use in electrical machines. With the help of the COMSOL Multiphysics software package, the possibility of determining the homogenized properties of carbon fiber bonded with epoxy resin was investigated, and the issue of determining the optimal sequence of sheets from the point of view of minimizing mechanical stresses was also considered. The application of a carbon fiber sleeve for a high-speed synchronous reluctance electrical machine has been considered. The mechanical analysis results indicate this technology's applicability in the field of high-speed electromechanics.Peer reviewe

Optimization of a High-Speed Synchronous Reluctance Machine's Rotor Topology

Publisher Copyright: © 2021 IEEE.Currently, due to the growing use of renewable energy technologies and hydrogen energy technologies, highspeed electric machines are of particular interest. High-speed electric machines have proven themselves well in compressor units and can improve the overall efficiency of the entire unit by eliminating the gearbox. However, the design and operation of these electric machines are accompanied by several difficulties, such as the resulting increased centrifugal forces, leading to increased mechanical stresses in the structure of the rotor. In this paper, a high-speed synchronous reluctance motor is considered as the object under study. The aim is to investigate the possibility of reducing mechanical stresses in the rotor steel by optimizing its topology while maintaining the output electromagnetic power.Peer reviewe