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The purpose of this paper is to present a detailed advanced dynamical model of induction machine (IM) with unskewed rotor bars, including rotor slot harmonics.

Procedure of IM modeling using results from finite element analysis (FEA). Series of magneto-static FEA simulations are used to obtain matrix of IM inductances as a function of rotor angular position and geometry. Each element in this matrix is represented by Fourier series (FS) and incorporated in proposed dynamical model. Using or neglecting various elements in FS of inductance matrix may be useful for determining which component of the series has dominant influence on harmonic content of stator currents, torque ripple or speed variation. The usefulness of application of presented model is verified comparing with time-stepping FEA simulations.

Although the model is not suitable for usage in on-line regulation of IM drives, but the results of simulations may be used to thoroughly explain origins of higher order harmonics in stator currents of IM and help improve sensorless speed estimation algorithms and fault diagnostics.

This paper shows an approach to the modeling of IM which includes effects of non-uniform air gap and non-sinusoidal distributions of magneto-motive forces. Inductance matrix elements are complex functions of rotor position, geometry and winding distributions and it gives an opportunity for detail analysis of IM behavior in numerous applications.

Synchronous Reluctance (SynRel) motors are known to suffer from excessive torque ripples. The classical way to avoid this drawback of the motor is skewing the slots. This paper aims to provide an analytic estimation of the best skew angle to minimize the ripples in such SynRel motors with tooth windings. The approach used in this paper consists of the minimization of the spectral components of the magnetic energy that cause these oscillation torques. The method was validated by means of a multi-slice finite element model (FEM).

An analytic model, based on permeance theory, is derived to analyse the electromagnetic phenomena taking place inside of the motor. This model allows the identification of the causes underlying the torque ripple production. Based on this understanding, the most suitable skew angle can be determined. The analytic method, together with the best skew angle, is validated by means of an FEM of a SynRel machine.

A method to determine the optimum skew angle for a SynRel machine is presented. It depends on the wave-number of the magnetic waves producing the torque ripple. It is twice the one typically chosen for induction machines.

The proposed approach allows improving on the design methodology for the production of smoothly running SynRel machines.

The methodology utilized in this paper is based on the relationship between the mechanical torque and the magnetic energy stored in the motor (virtual work law). From this, the best skew angle to eliminate the magnetic energy causing torque ripple can be determined. It, therefore, proposes an effective alternative to the common use of inductance models to determine such angles.

The paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. The set of loop differential equations was developed for Kth winding transformer model where the flux linkages of each winding includes a flux common Φ to all windings as function of magneto motive force Θ of all windings. The purpose of this paper is to first determine a hysteresis nonlinearity involved in Φ(Θ) function using modified Preisach theory and second to develop new analytical formula of Preisach distribution function (PDF).

It is assumed in this paper that flux linkage characteristics Ψ(i) of each winding have nonlinear component due to the magnetization characteristic of the steel core and sum of linear components due to the self and mutual leakage fluxes. This nonlinear component of Ψ(i) characteristic can be expressed as a flux common Φ to all windings vs ampere-turns Θ of all windings. The nonlinear flux linkage characteristics Ψ(i) of the tested transformer are calculated from the set of measured terminal voltages and terminal currents. To simulate magnetic behavior of the iron core the feedback scalar Preisach model of hysteresis is proposed which gives more accurate predictions than classical model. For this hysteresis model the PDF and feedback function are needed. The intend of this paper is to find these function as an analytical formulas which are convenient for numerical simulations. For identification of the PDF and feedback function parameters of the considered iron core of tested transformer the Levenberg-Marquardt optimization algorithm was used.

The flux common to all windings is calculated by integrating the induced voltages of the appropriate windings. In this paper the PDF is proposed as a functional series including two dimensional Gauss expressions. In order to proper approximation of hysteresis nonlinearity of the tested iron core the first three terms of functional series of the PDF have been used. In the optimization algorithm only initial and descending limiting hysteresis curves Φ(Θ) were utilized. The feedback function for proposed hysteresis model is assumed as third-order polynomial. The hysteresis model has been successfully validated by comparing the calculated and measured results of Φ(Θ) hysteresis curves. This hysteresis model can be used in transient and steady state simulations of tested transformer taking into account the hysteresis phenomenon. The developed hysteresis model can be also used for analysis of the influence of remnant flux on the operation of tested transformer especially in transient states.

In this paper the feedback Preisach hysteresis model is involved in the flux common to all windings vs ampere-turns of all windings. The new PDF is proposed as functional series including two dimensional Gauss expressions. For tested transformer the three first terms of this functional series may be used for proper approximation of hysteresis nonlinearities.

This paper aims to study the relationship between leakage flux coefficient and the coreless axial magnetic field permanent magnet synchronous generator (AFPMSG) size and obtain the expressions of leakage flux coefficient.

In this paper, a magnetic circuit model of coreless AFPMSG is proposed. Four kinds of leakage permeances of permanent magnet (PM) are considered, and the expression of no-load leakage flux coefficient is obtained. Solving the integral region of leakage permeances by generator size, which improves the accuracy of the solution.

Finite element method and magnetic circuit method are used to obtain the no-load leakage flux coefficient and its variation trend charts with the change of pole arc coefficient, air gap length and PM thickness. The average errors of the two methods are 2.835%, 0.84% and 1.347%, respectively. At the same time, the results of single-phase electromotive force obtained by magnetic circuit method, three dimensional finite element method and prototype experiments are 19.36 V, 18.82 V and 19.09 V, respectively. The results show that the magnetic circuit method is correct in calculating the no-load leakage flux coefficient.

The special structure of the coreless AFPMSG is considered in the presented equivalent magnetic circuit and equations, and the equations in this paper can be applied for leakage flux evaluating purposes and initial parameter selection of the coreless AFPMSG.

Velomobiles or bicycles cars are human-powered vehicles, enclosed for improving aerodynamic performance and protection from weather and collisions. The purpose of this paper is to design and develop a three-wheeled velomobile equipped with a hybrid human-electric propulsion system.

The mechanical layout has been developed in order to improve safety, a CAD code has been used for the design and the dynamic performances have been studied by means of specific multi-body codes. The electric propulsion system has been designed both with analytical and FEM methods.

A special three-wheeled tilting vehicle layout equipped with a four-bar linkage connection has been developed. A particular synchronous reluctance machine has been developed, which is very suitable for human-electric hybrid propulsion. A MATLAB code for integrated mechanical and electrical analysis has been developed.

A new kind of light vehicle has been conceived. A new synchronous reluctance machine with high efficiency has been developed. A performance analysis in electric, human and hybrid working modes has been presented, which takes into account the specific features of both the electric motor and the pedaling legs. A prototype of the vehicle has been built.

Finite‐element simulations of induction machines with squirrel‐cage rotor require transient solution algorithms. For this reason a transient 2D solver is utilized which takes rotational movement of the rotor into account. Its formulation and the time‐step algorithm are given. Two different kinds of eccentricity of the rotor and their combination are defined and studied. The three motor variants are computed and the torque, the net force, and the surface‐force density are compared in time and frequency domain.

This paper aims to propose a novel multiple transient modeling scheme for the 12-pulse phase-shifting reactor (PSR) rectifier to enhance the efficiency of full-cycle design evaluation.

The detailed time-domain method is adopted to model the rectifier at the behavioral layer. The diode bridges/transformer model at the architecture layer is established by using the switch function and Park transformation. The frequency domain model at the functional layer is derived with the time-varying Fourier decomposition and frequency-shifting. At the component layer, the magneto-thermal characteristics of the rectifier are analyzed with field-circuit and magnetic-thermal coupling methods. A computer-aided design program integrating multiple modeling is also developed for industrial product design.

The function layer modeling is preferred in the initial design stage, making up for the lack of modeling accuracy at the architectural layer and the lack of modeling rapidity at the behavioral layer. The component modeling is irreplaceable for the detailed evaluation in the latter design stage. The multiple modeling scheme based on the four-layer modeling helps the designers achieve high-quality products with a short development cycle.

The singular transient modeling cannot cover the needs of different stages in the full-cycle design evaluation. This paper fills this gap with a novel multiple modeling scheme. Meanwhile, the proposed multiple modeling scheme and developed computer-aided design program provide a great convenience for full cycle design evaluation of the 12-pulse PSR rectifier.

The purpose of this paper is to propose a method to estimate the magnetic saturation and end effect of linear switched reluctance machines (LSRMs) with fully pitched winding configuration used in the wave energy conversion.

The magnetic saturation and strong coupling make it very difficult to derive a comprehensive mathematical model for the behavior of the LSRMs. Meanwhile, the various end effects could not be comprehensively considered in the two‐dimensional model which is widely studied. Therefore, the magnetic equivalent circuit model including the three‐dimensional (3‐D) effects is presented in this paper and 3‐D finite element analysis (FEA) is used to validate the mathematical model.

The results from 3‐D FEA are in good agreement with the numerical simulation, which validates the accuracy of the magnetic equivalent circuit modeling method.

This technique helps one to know the influence exerted by the magnet saturation and end effect of LSRMs and provides a powerful computer‐aided analysis tool. Meanwhile, this modeling method supplies accurate values for the following study of reliable control algorithm.

The paper presents a magnetic equivalent method to estimate the magnetic saturation and end effect of LSRMs with fully pitched winding configuration used in the wave energy conversion.

An overview is given on design features, numerical modelling and testing of a novel electromagnetic actuator to achieve a controllable stiffness to be used as a device for parametric stiffness excitation.

In principle, the actuator consists of a current driven coil placed between two permanent magnets. Repellent forces are generated between the coil and the magnets, centering the coil between the two magnets. The 2D finite element analyses are carried out to predict the forces generated by this arrangement depending on coil current and coil position. Force measurements are also made using the actual device.

Actuator forces as predicted by the finite element analyses are in excellent agreement with the measured data, confirming the validity of the numerical model. Stiffness of the actuator is defined as the increase of force per unit of coil displacement. Actuator stiffness depends linearly on the coil current but in a nonlinear manner on the coil displacement. The performance of the actuator is sufficient to demonstrate the effect of a so‐called parametric anti‐resonance on a test stand.

Although the performance of the actuator is satisfactory, there is potential for further improvement of the actuator design.

This paper reports for the first time on an electromechanical device to create a time‐periodic stiffness variation to be used for research in the field of parametrically excited mechanical systems. The device is used to prove experimentally an effect to suppress mechanical vibrations which has been studied so far only in theoretical studies.

The aim of the paper is to explain and clarify the pre-processing for a finite element based wound rotor induction machine model.

The paper presents two algorithms. The first one speeds up the FE-simulations by changing the input parameter permutation scheme only. The second algorithm speeds up the quint-cubic spline parameter calculation by utilizing the continuity conditions between adjacent segments.

The paper provides comparisons of the calculation cost to show the advantages of the presented algorithms.

The algorithms explained in this paper allow a practical application of the finite element based model approach for a wound rotor induction machine. Therefore, this work completes the development of the finite element based wound rotor induction machine model.