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The purpose of this paper is to develop a system for estimating the position of the active magnetic bearing (AMB) shaft. A new approach using the static and dynamic inductances and complex analytic signal to simplify the estimation procedure. Finite element (FE) simulations are introduced as a part of the system synthesis.

The paper presents an AMB displacement estimation system. The system is created with three inductive sensors. The position is computed from refined static and dynamic inductance obtained from complex analytic signals of flux and current. FE simulation is used to relate refined inductances to the displacement and to verify the model.

This paper shows the applicability of complex analytic signal transformation on estimation systems. The use of new refined inductance is presented in contrast to the classical approach of static and dynamic inductances. The paper shows that classical approach of static and dynamic inductance is not usable for the presented estimation system.

For the practical implementation of the presented system, it is necessary to know the exact dimensions of the AMB stator and the voltage and frequency used to supply the inductance estimation system.

The paper presents a system for estimating the displacement of AMB. The paper introduces the application of complex analytic signal to the estimation of AMB displacement. The mentioned signal is used to compute the new refined inductances. The comparison to the classical approach of static and dynamic inductances is given in this paper. The paper introduces FE simulations to the estimation system synthesis.

To provide a general method for coupled simulation of electrical machines and circuits, using finite element analysis and a circuit/system simulator.

The electrical machine is modelled by dynamic inductance and electromotive force (EMF), which are determined by finite element analysis and updated in time‐stepping procedure. Calculation of these parameters is based on current perturbations that are applied on linearized field equations after determining the operating point by nonlinear analysis.

Based on the case studies, the presented method can be utilized in coupled field‐circuit simulation and the results correlate with those obtained by other known methods. The results were also validated according to experimental data.

Calculation of the EMF and the presented implementation for SIMULINK have some limitations regarding the accuracy and stability of the numerical integration. In the future, the numerical methods could be still improved and the implementations could be extended to other simulators.

Since the presented methodology is of a general type, the research provides means to include field‐circuit coupling into a variety of different simulation software.

Definitions of the circuit parameters differ from the conventional ones, as a result of which the parameter extraction can be performed in computation‐effective way. The benefits of the research are met widely, since the general‐purpose methodology is not limited to any single software.

Predictive controllers and permanent magnet synchronous motors (PMSMs) got more attention over the past decades thanks to their applicable features. This paper aims to propose and verify a method to design a predictive current controller with consideration of motor characteristics obtained from finite element analysis (FEA).

Permanent magnet motor parameters and its maps can be calculated by means of FEA. The model takes into account magnetic saturation and thermal electro-magnetic properties. For each dq current vector and each position, self and mutual inductances are calculated. Based on co-energy method and fundamentals of coordinate transformation dynamic and static, dq inductances are obtained. These are used in classical and modified dead-beat current controller equations.

To sustain good features of a controller over higher current regions, it is necessary to adapt control law of a dead-beat controller. After its modification, control quality can be superior over classical solution in high saturation regions. The transient simulations of controller and motor give accurate results.

Common predictive current controllers use nominal motor parameters in their equations. The authors proposed a modified dead-beat current controller to improve the control quality. There is no need to apply self-tuning algorithms, and implementation of the controller is not much more complicated than that of the classical controller. Designer of a control system can obtain required data from motor designer; in design process of modern machines such data are often already available. The proposed methodology increases control quality of the presented dead-beat controller.

Physical contact and traditional sensitive structure Physical contact and traditional pressure-sensitive structures typically do not operate well in harsh environments. This paper proposes a high-temperature pressure measurement system for wireless passive pressure sensors on the basis of inductively coupled LC resonant circuits.

This paper begins with a general introduction to the high-temperature pressure measurement system, which consists of a reader antenna inductively coupled to the sensor circuit, a readout unit and a heat insulation unit. The design and fabrication of the proposed measurement system are then described in detail.

A wireless passive pressure sensor without an air channel is fabricated using high-temperature co-fired ceramics (HTCC) technology and its signal is measured by the designed measurement system. The designed heat insulation unit keeps the reader antenna in a safe environment of 159.5°C when the passive sensor is located in a 900°C high-temperature zone continuously for 0.5 h. The proposed system can effectively detect the sensor’s resonance frequency variation in a high bandwidth from 1 to 100 MHz with a frequency resolution of 0.006 MHz, tested from room temperature to 500°C for 30 min.

Expensive and bulky equipment (impedance analyzers or network analyzers) restrict the use of the readout method outside the laboratory environment. This paper shows that a novel readout circuit can replace the laboratory equipment to demodulate the measured pressure by extracting the various sensors’ resonant frequency. The proposed measurement system realizes automatic and continuous pressure monitoring in a high-temperature environment with a coupled distance of 2.5 cm. The research finding is meaningful for the measurement of passive pressure sensors under a wide temperature range.

A three‐axes synchronous torque motor with permanent magnet excitation and solid stator and rotor yoke is used to adjust an air borne telescope and to eliminate oscillations. Hence the motor is part of a complex mechanical system and has to be included in the structural analysis. For this reason the attempt is made to simulate the nonlinear behavior of the motor by a dynamic model considering the eddy current fields and the magnetization characteristic of the iron.

The purpose of this paper is to investigate the influence of time steps, integration methods, and saturation modeling on the accuracy of the synchronous machine model. This model is compared with the PSCAD built‐in synchronous machine model in order to compare the accuracy of one of the most used synchronous machine models in a commercially available software versus a well‐documented and widely accepted state‐space synchronous machine model.

In the paper, a synchronous condenser with the saturation phenomenon is modeled using state‐space equations in the rotating dq‐reference frame and is implemented both in Matlab/Simulink and PSCAD. Integration methods of up to the fifth order are implemented for increased accuracy. The saturation modeling includes modeling of the saturation in both d‐ and q‐axis. A steady‐state and dynamic performance comparison towards the built‐in PSCAD synchronous machine model is performed. The saturation modeling does not include the saturation of the leakage fluxes.

When the forward Euler method is used, in order to obtain less than 5 percent error, the time step should not exceed 5 μs. The third‐order Runge‐Kutta method is the preferred choice and it provides desired accuracy when the time step is equal or smaller than 1,000 μs. The built‐in PSCAD model satisfies the error criteria for time steps smaller than 300 μs. A small discrepancy of 2 percent is found during the steady‐state test.

The paper presents the performance of the higher order integration methods in an EMTP‐type software environment where the trapezoidal integration method is most often used. It provides a good guide for building an owner‐defined model. A comparison of a dynamic performance between the publicly documented state‐space and a synchronous machine models commonly used for power system transient studies is presented.

When magnetic saturation in ac machines is evolved, the theory of main flux saturation in d-q axes remains the best. Because of its simplicity, it is the most used in either motoring or generating mode for synchronous or asynchronous machines. Although, it is considered as a global way of introducing the iron saturation, compared to other methods, today, its fidelity has no contest in predicting complex ac machine operations. For this purpose, the aims of this paper consists of modeling these machines whatever the state-space variables values are taking into account the magnetic saturation. Two unified procedures are proposed. The first one deals with a common approach to establishing a complete and detailed model synthesis in d-q axes. The second also presents a unified approach to introducing magnetic saturation of the iron core in the characteristic equations. The analysis takes the salient pole synchronous machine as a general case of study. Then the approaches are extended to undamped and smooth air gap synchronous machines as well as induction machines. The paper aims to discuss these issues.

The present paper, which is a first part of a work under study dealing with a unified method to derive multiple models of saturated ac machines, is intended to the description of an alternative method and its application for induction and synchronous machines. It mainly consists of the following parts: first, after writing the stator and rotor space vector d-q equations, the number of possible models is immediately discussed. By considering the currents and fluxes as state-space variables, 14 models are obtained for AC induction machine (IM and SM). They are classified into three families, current (three), flux (three) and mixed models (eight). Second, in order to easily introduce the magnetic saturation in the 14 developed models, a method is presented. It consists of just elaborating the model with the winding currents as state variables, then deriving all the other models from it. Third, to emphasize the influence of the presence of magnetic saturation, in each model, each inductance along the d and q axes is written with a fundamental expression which exists with or without saturation and an additional one due purely to saturation. Hence the additional terms can be studied and quantified in an easy way or simply removed when linear case is assumed. Fourth, adopting such strategy to write the different coefficients of the models had led to the definition of common saturation factors. In turn, the definition of common saturation factors had allowed the definition of different groups of models within each family. Fifth, an alternative to evaluate the static and dynamic saturation coefficients is also proposed. It is shown that by proper fitting of the experimental magnetizing curve, all saturation coefficients can be written only in terms of which is simply the magnitudes ratio of the magnetizing flux and current. Sixth, although the theory of the main flux saturation is now admitted, an investigation was carried out on a self-excited induction generator and the build-up of voltage and current phases of a standalone alternator, to prove the equivalence between the all developed models.

The number of models based on the state-space variables choice, of a saturated ac machine, is reviewed. A simple method consisting of elaborating just the winding currents model, with magnetic saturation and deriving all the other models from it, is presented. In this study special interest was particularly focussed on either novel models or existing models cited in the literature but cannot be obtained by other approaches. In all cases, if the differential equations of the machine are formulated in terms of a set of variables other than the winding currents, a noticeable reduction in the size of equations may be obtained and consequently less time computing. The approach seems to be able to derive any possible model whatever the state-space variables and the type of the ac machine and hence can be classified as a general approach.

The experiments of synchronous and induction machine transients prove the validity of the method.

By suitable choice of state-space characteristic vectors among the fluxes and the currents, a synthesis of AC machine models in d-q axes is established. To introduce magnetic saturation in each model, an approach-based uniquely on the elaboration of the winding currents model is exposed and applied. In addition, the analysis gives a detailed classification of all found models taking into account the state variables nature as well as the cross-coupling coefficient considered as a saturation factor. The study is completed with a simple alternative to evaluate all saturation factors by just calculating the static magnetizing inductance.

The purpose of this paper is to study the performance and efficiency of two different permanent magnet (PM) machine rotor configurations under magnetic core saturation conditions.

Since the accuracy of conventional analytical methods is limited under saturation conditions, a finite element model of the machine is built; which is used to predict the various losses over its operating range such as eddy current, hysteresis, copper and magnet losses. Using this model, the efficiency map of the machine is derived which is used to investigate its efficiency corresponding to a heavy vehicle drive cycle. The performance of two different rotor designs are studied and the efficiency of each design is compared under the considered drive cycle.

It has also been proved that the performance advantage due to reluctance torque in the v-shaped interior PM (IPM) machine is offset by its core steel saturation at higher current/torque levels. The magnitude of iron losses in the IPM is higher than that in the surface PM (SPM) machine, however, the magnet loss in the SPM is higher than in the IPM.

An investigation of the performance of the IPM design in comparison with the SPM∼design under magnetic saturation conditions is not known to the authors. Hence, in this paper, it will be determined if the assumed performance advantage of the IPM over the SPM still holds true under these conditions.

This paper presents a Newton‐Raphson algorithm for determining the Fourier spectrum of two‐periodic solutions for dynamic systems described by nonlinear ordinary differential equations. Assuming that two basic frequencies are known, the coefficients of a double Fourier series result from this algorithm. An application to the analysis of electromagnetic phenomena in electromechanical converters is described. In an example, of the steady‐state performances of current in a simple converter, the algorithm is tested with very good results.

The aim of the paper is to present the approximation methods of the magnetizing characteristics of the salient pole synchronous machines with the fundamental MMF harmonics.

The energy based approach is used to formulate a set of the functions approximating the magnetic flux linkages versus an equivalent magnetizing current in the circuit model of the synchronous machine. The estimation of the approximation functions parameters is based on the results of the field calculations.

The identification of the approximation functions is effective and significantly simpler on the basis of the magnetic field co‐energy function, than on the basis of the magnetic flux linkages.

The magnetic field co‐energy function determined by FEM is sufficient for simplified calculations of the magnetic parameters occurring in the circuit models of the electrical machines with nonlinear core.

The paper provides guidance for the circuit modelling of the multi‐pole generators and motors under conditions of magnetic saturation.

A paper has succeeded in determining the internal magnetic characteristics of the synchronous machine with a salient pole rotor.