# Numerical Analysis of Electrical Machines

EELAB has a many years' experience in developing numerical tools for analysing electrical machines and drives. Both dedicated software for dealing particular problems, such as magnetic forces and torque ripples in induction machines, and more general software for modelling electrical machines, based on the finite element method, have been developed.

Besides in-house developed software, also (free and commercial) software is used for the numerical analysis of electrical machines and devices.

The finite element simulations are used e.g. for the integrated modelling of complete electrical drives and for the optimized design of electrical machines.

## Examples

### 2D finite element software for the dynamic simulation of electrical machines

At EELAB a finite element package has been developed for the simulation of electrical machines including the following features:- static and dynamic simulations (both time stepping and frequency domain analysis)
- two-dimensional FE models
- material and lamination models for including hysteresis and eddy current losses
- multi-slice model for skewed machines
- FE machine model coupled with an electrical circuit (converter) and kinematic equations (of the load)
- computation of losses, torque ripples, etc.

### Radial magnetic forces and torque ripples in induction machines

Radial forces are an important source of vibrations and noise in electrical machines. A software package for computing radial forces and torque ripples in induction machines has been developed. The computation method takes into account the various effects which determine the spectrum of the vibrations and noise: eccentricity, saturation, harmonics of the applied voltage, mmf harmonics, etc.## Relevant publications

- K. Geldhof, T. Vyncke, F. De Belie, L. Vandevelde, J. Melkebeek, R. Boel

*Embedded Runge-Kutta Methods for the Integration of a Current Control Loop in a SRM Dynamic Finite Element Model'*

IET Science, Measurement and Technology, Vol. 1, No. 1, January 2007, pp. 17-20 - F. Bokose, L. Vandevelde, J. Melkebeek

*'Prediction of core losses in switched reluctance motors using finite element method and rainflow algorithm'*

in Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, A. Krawczyk, S. Wiak and X. M. López-Fernández (Eds.), IOS Press, 2006, ISBN 1-58603-627-0, pp. 281-289 - J. Gyselinck, L. Vandevelde, J. Melkebeek

*'Multi-Slice FE Modeling of Electrical Machines with Skewed Slots - The Skew Discretization Error'*

IEEE Transactions on Magnetics, Vol. 37, No. 5, Sept. 2001, pp. 3233-3237 - J. Gyselinck, L. Vandevelde, D. Makaveev, J. Melkebeek

*'Calculation of No-Load Losses in an Induction Motor Using an Inverse Vector Preisach Model and an Eddy Current Loss Model'*

IEEE Transactions on Magnetics, Vol. 36, No. 4, July 2000, pp. 856-860 - L. Vandevelde, C. Rasmussen, J. Melkebeek

*'Radial forces and torque ripples in split-phase induction motors'*

Proceedings of the 17^{th}International Conference on Electrical Machines (ICEM 2006), Chania, Crete Island, Greece, 2-5 September 2006, paper PSA3-1