Nelson Sadowski

Finite element torque calculation in electrical machines while considering the movement

Different methods are presented for the calculation of torque as a function of rotation angle in an electrical machine. These methods are integrated in a calculation code by using the finite element method. The movement is taken into account by means of the moving band technique, involving quadrilateral finite elements in the airgap. The torque is calculated during the displacement of the moving part by using the following methods: Maxwell stress tensor, coenergy derivation, Coulombs virtual work, A. Arkkios method (1988), and the magnetizing current method. The results obtained by the different methods are compared with experimental data and make it possible to obtain practical information concerning the advantages and limitations of each method. >

An inverse Jiles-Atherton model to take into account hysteresis in time-stepping finite-element calculations

A modified Jiles-Atherton model presenting the magnetic induction as an independent variable is proposed in order to be directly used in time-stepping finite-element calculations applied to the magnetic vector potential formulation. This model is implemented in the field calculation procedure by introducing a differential reluctivity. The calculated results are validated by experiences performed in an Epsteins frame.

Real coded genetic algorithm for Jiles-Atherton model parameters identification

The parameters set of the Jiles-Atherton hysteresis model is identified by using a real coded genetic algorithm. The parameters identification is performed by minimizing the mean squared error between experimental and simulated magnetic field curves. The procedure is validated by comparing experimental and simulated results.

Compensation of permanent magnet motors torque ripple by means of current supply waveshapes control determined by finite element method

A method for determining the supply current waveshapes for torque ripple compensation in permanent-magnet motors without saliency and damping bars, by means of a finite-element code, is presented. First, a theoretical analysis shows that current waveshapes producing constant torque can be determined. This analysis leads to an expression for the current as a function of the motor EMF (electromotive force) and cogging torque. Several methods, based on finite-element computation of the magnetic field, for computing the cogging torque and EMF are proposed and compared. A special experimental bench for motor torque measurement is used to validate the theoretical results. >

Finite element simulation of electrical motors fed by current inverters

This paper presents a methodology for coupling electrical machines represented by a Finite Element Model and power electronic devices. The technique, based on a time-stepping procedure for the simultaneous solution of the field and the electrical circuit equations, is applied to an inverter current fed permanent magnet motor.

The inverse Jiles-Atherton model parameters identification

An optimization procedure to obtain the parameters of both the original Jiles-Atherton and the inverse Jiles-Atherton hysteresis models is presented in this paper. Doing so, minor loops can be conveniently simulated without inserting scaling methods. The comparison between experimental and calculation results validates the procedure.

A new approach for iron losses calculation in voltage fed time stepping finite elements

A methodology allowing one to include iron losses in voltage fed time stepping finite elements simulations is presented in this paper. Hysteresis, eddy currents and anomalous losses models are introduced in the 2D field formulation based on the magnetic vector potential. The influence of the losses on the behavior of an Epstein frame is given. Comparison between simulated and measured results shows the validity of the proposed methodology.

Finite elements coupled to electrical circuit equations in the simulation of switched reluctance drives: attention to mechanical behaviour

A method to model the switched reluctance motor is presented in this paper. The methodology is based on the simultaneous solution of the magnetic field, represented by the two-dimensional finite element method, with electrical circuit equations. With this model, the currents in the windings are calculated and the force distribution on the stator teeth is obtained. The mechanical response to magnetic forces is calculated by a finite element code.

Coupled field and circuit analysis considering the electromagnetic device motion

This paper deals with a simultaneous analysis of electromagnetic structures, represented by 2D finite elements, connected to their feeding circuit. As the main contribution, the electromagnetic device motion is taken into account. The proposed methodology is based on the sequential resolution of circuit, field and mechanical equations. The circuit equations are determined automatically during the simulation.

Calculation of electromagnetic-mechanic-acoustic behavior of a switched reluctance motor

This paper deals with the coupling between magnetic forces, forced vibrations and noise in a Switched Reluctance motor. The finite element method is used to obtain the magnetic forces and forced vibrations. The boundary element method is used for acoustic computations.