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The phase-domain synchronous machine model has advantages compared to the d/q model, as no transformation of currents is necessary at each time step in a network analysis. The purpose of this paper is to enhance the phase-domain model to calculate the current distribution of the damper bars, including the saturation.

The new enhanced phase-domain model of the synchronous machine has been modelled using Matlab-Simulink. The parameters of the model have been calculated by using FEA software.

It is shown that the simulation results of the new model show very good accordance to the reference model during a three-phase short circuit.

The enhanced model includes the calculation of the currents in the damper bar and is able to include the harmonics of the inductances.

Operation of synchronous machines in the power range of several 10 MW with variable speed up to 7,000 rpm using a current converter is, thanks to the development of power switches, possible and economically reasonable today. However, current harmonics, produced by converter, generate additional losses, especially eddy current losses on the rotor surface are produced by the converter, which strongly depend on the rotor permeability. The purpose of this paper is to show that an accurate machine modeling is required, in order to consider the nonlinearity of electromagnetic processes inside.

This paper concentrates on the determination of the rotor surface losses in a three‐phase turbogenerator feeding a current converter. Saturation of rotor steel is taken into account using a transient finite element method model of the machine, coupled with a converter model.

A detailed analysis of the damper currents and losses in a turbogenerator operating with a frequency converter is presented. The effectivenes of damper winding modifications, concerning the eddy current loss reduction in the rotor surface, is depicted.

The introduced modelling technique presents an accurate electromagnetic modelling of an I‐converter‐fed synchronous generator with massiv poles, which is fed by a current converter and so has to sustain additional eddy current losses in the rotor surface. In this way, the amount and distribution of these losses are evaluated more accurately which allows a more efficient design of the damper winding as well as machine cooling system.

Some researchers have made contributions to the analysis of current converter‐fed synchronous machine, regarding terminal behaviour of the machine. This paper focuses on eddy current losses on the rotor surface, considering the time and space dependent saturation aspect in the machine, particularly in the rotor.

Magnetic slot wedges are usually installed in open slot high-voltage induction machines. They reduce the no load losses and the magnetization current. Additionally, the leakage inductance increases. However, machines and the slot wedges are getting frequently damaged with a decreasing maintenance interval. The usage of magnetic slot wedges leads to unknown effects. It is possible, that direct magnetic forces or indirect forces, caused by the deformation of the stator or stator teeth during operation, results in the damage of the slots wedges. The purpose of this paper is to fully understand the influence of the magnetic slot wedges and the intrinsic effects.

A finite element model of the affected machine is verified with current and torque values from the data sheet of the affected machine. Three types of forces, which are working on the slot wedges, are considered and compared.

There are direct forces working on the slot wedges. The origin of this forces and a coherence between this forces and the slot number relationship, between stator and rotor slots is shown as well as reasons for the damage to the slot wedges.

There are investigations about the influence of the behaviour of an induction machine by magnetic slot wedges. This investigations consider the influence on the network models of such machines. The paper at hand deals with the intrinsic effects caused by the slot wedges and its consequences.

The purpose of this paper is to find a simple structure of motion controller for permanent magnet direct drive. Application of sliding mode controller theory and equivalent disturbance estimator creates proper non‐linear characteristics, which ensures controller robustness against friction.

The position and speed controller is based on robust design methodology introduced by a sliding mode technique. The paper proposes a combination of sliding mode controller and proportional integral (PI) equivalent disturbance estimator. The friction model is Coulomb friction with a large static friction effect. The double boundary layer is used to compensate the effect of stiction. The synthesis is performed using simulation techniques and subsequently the behaviour of a laboratory speed control system is validated in the experimental setup. The control algorithms of the system are performed by a microprocessor floating point DSP control system.

The proposed sliding mode controller structure with equivalent disturbance estimator guarantees expected robustness against friction. Experimental results show that the control approach can decrease the tracking error, enhance the system's robustness and attenuate high‐frequency chattering in the control signal.

The proposed controller was tested on a single machine under well‐defined conditions. Further investigations are required before any industrial applications.

The proposed controller synthesis and its results may be very helpful in robotic systems where non‐linear friction is a characteristic for many industrial robots and manipulators.

The method of sliding mode controller synthesis was proposed and validated by simulation and experimental investigations.

The purpose of this paper is to describe a systematic investigation of the currents, torques and other electromagnetic quantities in a machine after different short circuits by the means of coupled numerical field and network calculation. The behaviour of a synchronous machine after a stator‐winding fault still is a little known issue. Nevertheless, the occurrence of winding faults can damage the stator winding of the machine severely and may also destroy the whole stator core. Therefore, there exists a strong need for reliable calculation methods for the evaluation of these faults, e.g. the reconstruction of the details of an accident.

The paper discusses an analytical approach which calculates all possible winding connections when absence of nonlinear material behaviour is assumed and nonlinearity is only considered by adjusting the inductances after solving the differential equations. In the following, a more accurate method is given by the numerical field calculation, considering a two‐dimensional time variant permeability distribution on the cross‐section of an electrical machine.

First results of transient time‐stepping calculations of short circuits with special respect on winding currents and radial forces on the rotor are presented.

The approach presented in this paper can be applied in the field of R&D for the dimension of electrical machines and its protection system as well as for the investigation of possible sources of an occurred machine failure.

The bulk of publications that contribute to the topic of inner winding faults are comprised of derivations of analytical models with the assumption of linear material behaviour. The paper puts strong emphasis on the consideration of the nonlinearity.

Nowadays many parameter studies for the design and optimization of electromagnetic devices are carried out by means of 2D and 3D nonlinear finite element (FE) models. Through optimization algorithms selecting one design as optimal with respect to the chosen cost function, the user does not gain any intuitive clue of the interrelations existing between design parameters, although numerous computations have been performed across the whole parameter space of the system. The purpose of this paper is to visualize a complex nonlinear FE solution system, which is parameterized through a number of control variables, in virtual reality (VR).

This paper presents a visualization approach for n‐dimensional parameter spaces of FE solutions in VR and the corresponding interpolation methods for enabling navigation through it.

The solution of an arbitrary electromagnetic FE problem is categorized with respect to possible changes, due to chosen design parameters, within the solution itself and variations in the underlying mesh in order to find appropriate interpolation methods for the visualization of each type of parameter space.

The implementation is based on modifying the popular Visualization Toolkit (VTK).

The paper presents different solution approaches for the visualization of an interpolation between arbitrary different meshes, but the problem remains unsolved and requires further research.

The purpose of this paper is to elaborate a mathematical model of dynamic operation of the permanent magnet brushless DC (BLDC) motor with outer rotor and investigate the influence of magnets width on the dynamic parameters.

The mathematical model of the devices includes: the equation of the electromagnetic field, the electric circuit equations and equation of mechanical motion. In elaborated algorithm, all these equations are coupled – therefore they are solved simultaneously. The numerical implementation is based on finite element method and step‐by‐step algorithm. The non‐linear‐coupled field‐circuit equations have been solved by using the Newton‐Raphson algorithm. The computer code for dynamics simulation of the machine has been developed.

The elaborated algorithm and the computer code have been applied for the 2D simulation of BLDC motor dynamics. The algorithm has a good convergence and its usefulness was proved. Various results of the analysis are presented and discussed.

The presented approach and computer code can be successfully applied to the design and optimization of different structure of the BLDC motors.

The purpose of this paper is to present a modification of the Park variable transformation for a three‐phase wye‐connected winding without neutral wire. A new physical interpretation of the winding equivalent circuit is proposed.

An equivalent circuit representing reluctance motor stator winding is rearranged to enable easier physical interpretation of obtained voltage equation. The Park transformation and constraints resulting from Kirchhof's laws are then applied to obtain a two‐axis mathematical model of the motor.

A new physical two‐phase interpretation of the voltage equation for a three‐phase wye‐connected winding without neutral wire is proposed. A novel two‐axis transformation is formulated for all variables. Compared to the Park transformation, which is the same for all variables, in the proposed transformation its matrices for currents and voltages/flux linkages are different, yet strongly interconnected.

The proposed transformation is formulated for a specific type of winding connection scheme. Therefore, it is limited in its application.

From the practical point of view, the proposed transformation could be very useful as it applies to the most popular stator winding connection scheme. Its main advantages are fewer number of trigonometric parameters in the matrices and measurability of all currents and voltages present in its voltage equations. It could be of special importance for electric machines with non‐sinusoidal field distribution (e.g. Brushless DC).

The paper presents a new type of variable transformation for three‐phase electric machines with wye‐connected windings without neutral wire. Proposed transformation combines different transformations for currents and voltages/flux linkages.

The aim of the paper is to present the methodology of obtaining an approximate equivalent circuit composed of lumped parameters which describes an electromagnetic state of induction machines (IMs) with solid secondary. Higher space harmonic field components are taken into account. The proposed method of machine model constructing is useful for solving electrodynamics states of solid secondary IMs, as well linear machines.

A determination of equivalent circuit parameters of a polyharmonic machine is divided into two steps. In the first step, frequency plots of the spectral inductances are derived – for each of the space harmonic components – from an electromagnetic field distribution calculated by means of the finite element method. In the second step, each of the spectral inductances are represented by the operational inductances which corresponds to the equivalent circuit composed of parallel connected the magnetizing inductance and branches consisting of resistance and inductance connected in series.

The proposed method allows the construction of the approximate equivalent circuit with lumped parameters which enables to solve electrodynamic states of solid secondary IMs, as well linear machines. The machine model has been derived with consideration of the higher space harmonic field components.

Saturation effects of a magnetic circuit and an unbalance of phase currents have not been taken into account.

The paper shows the method of constructing a machine field‐circuit model. Lumped parameters of the model have been derived using frequency characteristics of the stator spectral inductance with consideration of the higher space harmonic field components.