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According to data from the literature, intraorbital involvement in multiple myeloma is rare. Such involvement may result in exophthalmia, itself the first manifestation and presenting feature of myeloma. These lesions can respond remarkably to radiotherapy. The authors present a new case report.

The inhibitory effects of extracts from Phaseolus vulgaris and Vicia faba beans, obtained from boiled beans, on the corrosion of EN Fe37-3FN mild steel in a 0.5 M hydrochloric acid medium were meticulously investigated utilizing electrochemical techniques and Electrochemical Impedance Spectroscopy (EIS). The corrosion rate was observed to decrease by 40% upon the introduction of 20 mg/L of the Phaseolus vulgaris extract, with a notable reduction of 70% when the concentration was increased to 2 g/L and beyond. The Vicia faba extract, however, displayed a slightly inferior inhibitory performance, with corrosion rates diminishing by 20% at 20 mg/L and 60% at concentrations of 2 g/L and above. The adsorption of extract constituents onto the steel surface was found to conform to the Langmuir adsorption isotherm model, thereby facilitating the calculation of the sorption equilibrium constant and revealing that the adsorption was primarily physical in nature. These extracts, which are typically discarded by-products of bean cooking, have emerged as cost-effective, readily accessible, and environmentally benign alternatives for mitigating steel corrosion in acidic environments. [ABSTRACT FROM AUTHOR]

The contactless transmission between the conductor rotor and the permanent magnet (PM) rotor of an adjustable permanent magnet coupler (APMC) provides the device with significant tolerance for alignment errors, making the performance estimation complicated and inaccurate. The first proposal of an edge coefficient in this paper helps to describe the edge effect with better accuracy. Accurate equivalent magnetic circuit (EMC) models of the APMC are established for each region. Models of magnetic flux, magnetic resistance, and eddy current density are established by defining the equivalent dimensional parameters of the eddy current circuit. Furthermore, the concept of magnetic inductance is proposed for the first time, parameterizing eddy currents that are difficult to describe with physical models and achieving the modeling of the dynamic eddy current circuit. The magnetic resistance is subdivided into two parts corresponding to the output and slip according to the power relationship. Furthermore, eddy current loss and dynamic torque models are further derived. The method proposed in this paper enables the APMC to be modeled and calculated in a completely new way. The correctness and accuracy of the model have been fully demonstrated using finite element simulation and an experimental prototype. In addition, the limitations of the proposed method and the reasons are fully discussed and investigated. [ABSTRACT FROM AUTHOR]

In this study, a generalized torque estimation method is proposed for synchronous motors, including surface permanent magnet synchronous motors (SPMSMs), synchronous reluctance motors (SynRMs), and interior permanent magnet synchronous motors (IPMSMs) for building the analytical motor model. The average motor torque is estimated using the Lorentz force by the generated flux density in the air gap to determine the relationships among torque, flux density, and injected current. In the proposed method, the generated flux density is derived step by step by considering the effects of magnetic flux saturation, the stator slot, the rotor barrier, and permanent magnets (PMs) to ensure that the generated average torque complies with the operating condition of the motor. To verify the proposed method, the output torque of finite element analysis (FEA), Maxwell 2D, is compared to the proposed method in a SPMSM. Moreover, a phasor diagram is plotted to determine the mechanism through which torque is generated in SynRMs and IPMSMs. A SynRM and an IPMSM with ferrites PMs are analyzed using the proposed method, FEA, and the experimental results of this study indicate the effectiveness. [ABSTRACT FROM AUTHOR]

Electric motor development is a challenging task, as higher efficiency requirements and various interdependencies between different engineering domains must be considered. Established design approaches often lack the ability to address these interdependencies because they focus on specific domains and properties. Automated, multidisciplinary design approaches hold untapped potential for optimizing motors in terms of diverse requirements and advancing the development of more efficient and reliable motors. This paper presents a systematic literature review of the current state of research in the multidisciplinary design automation of electric motors. The literature basis comprises 1005 publications that are identified by a systematic internet search. The review of the existing approaches is based on twelve criteria that characterize the design automation task in general, such as knowledge representation or reasoning methods used, as well as criteria specific to electric motor design, such as domains considered and their coupling. The analysis reveals what current approaches are lacking: Consequent analysis and integration of domains, applicability of suggested methods, incorporation of established multidisciplinary design optimization (MDO) architectures, alongside the consideration of passive components in the motor. Aside from the introduction of twelve criteria for systematic charaterization of multidisciplinary design automation of electric motors, this article expands the state of the art by proposing an initial framework to establish process chains tackling the identified gaps in the review. [ABSTRACT FROM AUTHOR]

Featured Application: This paper proposes a new hybrid vibration isolation system that combines an electromagnetic actuator, rubber passive vibration isolator, and magnetorheological damper, and it has a high bearing capacity, high output force, low power consumption, and good impact resistance. First, the overall design scheme of the hybrid vibration isolation system is introduced. The electromagnetic actuator is simulated with electromagnetic–mechanical coupling in the time–frequency domain. A dynamic stiffness test is carried out on the rubber vibration isolator. Then, the adaptive suppression filtered-x least mean square (ASFXLMS) algorithm is proposed to adjust the update of the control weight coefficients, by introducing a suppression factor to improve the robustness of the algorithm. Finally, a hybrid vibration isolation system-based active vibration isolation experimental platform is built, and multifrequency line spectra active–passive vibration isolation experiments are carried out. The results demonstrate that the hybrid vibration isolation system has good control effects in the time–frequency domain and shows a good robustness when subjected to impact. Targeting the problems of conventional active–passive hybrid vibration isolation systems, such as low output force, poor bearing capacity, large power loss and inability to withstand strong impacts, this paper proposes an active–passive hybrid vibration isolation system combining an electromagnetic actuator, rubber passive vibration isolator and magnetorheological damper. The overall design of the hybrid vibration isolation system is first introduced. Then, a two-dimensional electromagnetic frequency-domain simulation is carried out on the electromagnetic actuator to obtain the output characteristics. A three-dimensional modeling is conducted to simulate the electromagnetic–mechanical coupling in the time–frequency domain to obtain nephograms of the magnetic flux diffusion distribution and power loss. Then, a dynamic stiffness test is carried out on the rubber vibration isolator to obtain the dynamic stiffness characteristics and the damping angle curve. At the same time, an adaptive suppression filtered-x least mean square (ASFXLMS) algorithm is proposed to adjust the update of the control weight coefficients to ensure that the current signal does not exceed the effective operating range of the actuator when the electromagnetic actuator is subjected to strong external disturbances. Finally, a hybrid vibration isolation system-based active vibration isolation experimental platform is built, and multifrequency line spectra active–passive vibration isolation experiments are carried out. The results demonstrate that the hybrid vibration isolation system has good control effects in the time–frequency domain and shows good robustness when subjected to impact. [ABSTRACT FROM AUTHOR]

Due to the high cost and the predicted shortage of rare earth elements in the near future, the task of developing energy-efficient electric machines without rare earth magnets is of great importance. This article presents a comparative analysis of optimized designs of a ferrite-assisted synchronous reluctance machine (FaSynRM) and a ferrite-assisted synchronous homopolar machine (FaSHM) in a 370-kW subway train drive. The objectives of optimizing these traction machines are to reduce their losses, maximum armature current, and torque ripple. The optimization considers the characteristics of the machines in the subway train moving cycle. The problem of the risk of irreversible demagnetization of ferrites in the FaSynRM and FaSHM is also considered. To reduce the computational burden, the Nelder-Mead method is used for the optimization. It is shown that the FaSHM demonstrates better field weakening capability, which can reduce the maximum current, power, and cost of the inverter power modules. At the same time, the FaSynRM requires less permanent magnet mass for the same torque density and is more resistant to irreversible demagnetization, which can reduce costs and improve the reliability of the electric machine. [ABSTRACT FROM AUTHOR]

This study focuses on implementing a wind turbine emulator based on a permanent magnet synchronous machine with excitation auxiliary windings and thoroughly investigates the space harmonics created by this innovative topology in MATLAB/Simulink. A Hybrid Generator (HG) is a robust generator that does not have slip rings or brushes in its structure. Furthermore, the flux of the hybrid generator HG may be easily adjusted as it is created by direct current excitation coils and permanent magnets. Unfortunately, the space harmonic rate in the HG is relatively high. In other words, the mechanical vibrations caused by the electromagnetic torque ripple threaten the drive train's behaviour and, ultimately, the wind turbine's lifespan. This study describes two methods for decreasing the ripple in electromagnetic torque. Both circuit architecture and robust H∞ control techniques are considered. After simulating the two approaches, a list of requirements is provided for the maximum allowable amplitude of the inductance and the flux harmonics. [ABSTRACT FROM AUTHOR]

This paper is the first that proposes an extended hybrid analytical method (HAM) based on a two-dimensional (2-D) coupling between the semi-analytical Maxwell-Fourier analysis and finite-element method (FEM) in polar coordinates. The proposed model is applied to any rotating electrical machines. The main objective of this paper is to establish the magnetic field solution in the whole machine by coupling an exact analytical model (AM), proposed for all regions having relative magnetic permeability equal to unity, with a FEM in ferromagnetic regions. The AM and FEM are coupled in both directions (r , θ) in the edge separating teeth regions and all its adjacent regions by applied boundary conditions (BCs). The developed HAM gives accurate results on the magnetic flux density distribution and the cogging torque whatever the operating conditions, the magnetic or geometric parameters. All results obtained give very satisfactory agreement with 2-D finite-element analysis (FEA). [ABSTRACT FROM AUTHOR]

Electric machines are important devices that convert electrical energy into mechanical energy and are extensively used in a wide range of applications. Recent years have seen an increase in applications where electric motors are used. The frequent use of electric motors in noise-sensitive environments increases the requirements placed on electric motors intended for these applications, especially when compared to electric motors commonly used in industrial applications. This paper provides a comprehensive review of electric motor noise. Firstly, a brief introduction to noise is given. Then, the sources of electromagnetic noise and vibration in electric machines, including mechanical, aerodynamic and electromagnetic factors, are presented. Different methods such as analytical, numerical and semi-analytical for calculating electromagnetic force, natural frequencies and noise are also analyzed. Various methods for noise reduction are presented, including skewing, stator and rotor notching and slot opening width. Finally, noise measurement standards and procedures are described. [ABSTRACT FROM AUTHOR]

This study employed Benincasa hispida peel as a raw material for the preparation of Benincasa hispida peel extract (BHPE) via hot water extraction and freeze-drying processes. The synergistic effect of BHPE and KI on the corrosion inhibition of mild steel in 1 M HCl was investigated. The compositional analysis shows that BHPE consists mainly of a mixture of sugars, characterized by a high density of hydroxyl groups and unsaturated functional groups, characteristic of highly effective corrosion inhibitors. Electrochemical experiments and surface analysis show that the composite of BHPE and KI can effectively provide protection to mild steel. Moreover, the synergistic coefficient of BHPE and KI under various concentration conditions was greater than 1, and the highest corrosion inhibition efficiency was 94.4%. In addition, the corrosion inhibition mechanism of BHPE was thoroughly investigated using quantum chemistry (QC) and molecular dynamics simulation (MDS). [ABSTRACT FROM AUTHOR]

In this contribution, a tool developed for the study of the efficiency maps of shifted inductances axes permanent magnet synchronous motors (SIAPMSMs) is presented and made available to the readers. The research builds upon a shared foundation that has already been established in previous works focused on the power capability of synchronous machines. This contribution is an extension of previous works dedicated to the power capabilities of shifted inductances axes synchronous motors where the losses were not considered. In this new contribution, the SIAPMSM models, which include the electromagnetic losses (joule and iron losses), are discussed. The mechanical losses are not included. The classical permanent magnet synchronous machines can be considered a particular case of a SIAPMSM. They will be used to validate the developed tools. The validation study is conducted by comparing the power capabilities and the efficiency maps of SIAPMSMs and classical PMSMs obtained by the newly developed modeling tool and a previously developed modeling tool. [ABSTRACT FROM AUTHOR]

A new level set method is developed for multi-material structural topology optimization. The method features in using the discontinuous Galerkin finite-element method for discretization of the level set transport equation and the distributed shape gradient. Moreover, the topological derivative is incorporated into the present algorithm as a possible way to escape from local minima through creating holes during optimization. Numerical examples are provided to verify effectiveness of the numerical algorithm. [ABSTRACT FROM AUTHOR]

Permanent magnet (PM) machines with fractional slot concentrated windings (FSCW) constitute a notably remarkable proposition for electric vehicles. Additionally, an integrated onboard battery charger (IOBC) provides another superiority as it exploits the components of the powertrain to charge the battery without any additional components. Interior permanent magnet (IPM) motor arises as a credible choice due to its high torque density, resulting from the high saliency ratio. The optimal design of an IPM motor has been extensively presented from different perspectives, but the optimal design of a motor employed for IOBC application for both propulsion and charging modes has not been studied extensively. In this paper, the design and optimization of a 12-slot/10-pole IPM motor with IOBC are studied under both propulsion and charging modes. A finite-element-based optimization with the aid of a genetic algorithm technique is proposed to obtain the optimal machine by maximizing the average torque and minimizing the torque ripple, core losses, and magnet size. [ABSTRACT FROM AUTHOR]

The use of electric motors, and particularly, Permanent Magnet Synchronous Motors, is increasing in recent years, and their vibration response is one of the most crucial aspects regarding their behaviour. Thus, the reduction in vibrations is one of the key objectives when optimizing electric motors. In an initial design state, the influence of the main design parameters on the behaviour of the machines is not always clear. For that reason, this work presents a global sensitivity analysis procedure that allows identifying the most influential design parameters and determining guidelines to optimize the design of Permanent Magnet Synchronous Motors. First, the analytical calculations employed to estimate the electromagnetic torque and the vibration response of the machine are described. Then, the sensitivity analysis procedure, based on the Monte Carlo method, is presented, and the conditions to apply the method successfully and accurately are analysed. Finally, the sensitivity analysis is performed for a particular electric motor design, and some general design guidelines are deduced, which can be extrapolated to similar machines. [ABSTRACT FROM AUTHOR]

Nowadays, research on electromagnetic devices increasingly focuses on multiphysics three‐dimensional complex systems. However, this kind of simulations require huge computational resources and consequently very high CPU time. Ristagno et al. proposed a level‐set based method allowing meshing step savings in any iterative processes (as movement modeling or optimization processes). The level‐set method lies in implicit description of moving fronts as described in the study by Osher et al. (1988). Inspired by Räisänen et al., all physical parameters (material properties, supply or armature movement) are implemented by projection of mathematical functions. In this paper, the authors proposes to study and design a new kind of mechanical commutator for DC machines thanks to this coupled method. Indeed, there is a renewed interest in DC machines because they can be suitable for small mobilities. To be noted, small mobility concerns all kind of vehicles (2 wheels–4 wheels–autonomous vehicles such as drones) that have speeds below 50 km/h. However, specifications for traction applications are difficult to achieve for such a rustic machine and requires some modifications. That is why, inspired by usual synchronous machine, the commutator has been redesigned to obtain expected theoretically signal waveform. Furthermore, numerical coupled simulations have been used to design both machine and supply simultaneously. This work has led to the manufacture of a proof of concept and preliminary results are very promising. [ABSTRACT FROM AUTHOR]

In order to solve the optimization problem of the disk magnetic coupler, the two optimization schemes, the orthogonal test and multiobjective genetic algorithm, were used to optimize the disk magnetic coupler to maximize the magnetic torque while reducing the eddy current loss, and then the correctness of the optimization results was verified by electromagnetic simulation experiments. The eddy current loss and magnetic torque of the optimized disk magnetic coupler were normalized by using the comprehensive evaluation function. After orthogonal test and multiobjective genetic algorithm optimization, the comprehensive evaluation value of the disk magnetic coupler increased by 2.43 times and 3.30 times, respectively, and the optimization effect of multiobjective genetic algorithm is more significant. The relative errors between theoretical and simulated values of the maximum magnetic torque and eddy current loss by multiobjective genetic algorithm are 2.22%–4.72% and 1.13%–6.41%, respectively, suggesting that the optimization method is feasible. The research results show that the multiobjective genetic algorithm optimization can significantly improve the performance of magnetic disk coupler, which can provide theoretical and technical basis for the design of disk magnetic coupler. [ABSTRACT FROM AUTHOR]

In this paper, a variable reluctance generator with segmental stator utilizing an assisted DC field for variable speed applications is proposed. In this work, analytical design, magnetic field analysis, and Parametric Sensitivity Analysis of the proposed machine are presented. The stator of suggested configuration, in addition to the distributed phase windings, is included the distributed assisted dc field coils, which are responsible for producing an adjustable magnetic flux in the generator. The segmental stator, the controllability of magnetic flux and generated voltage are the prominent features of the presented generator. Maintenance-free and easy accessibility of each stator segment due to utilizing the segmental stator, and high reliability due to the absence of brush and winding on the rotor is other features of the proposed machine. Finally, the Field Analysis using the finite element method is performed to verify the analytical design and sensitivity analysis. The results obtained from the FE analysis confirm the analytical design and the controllability of magnetic flux and generated voltage for the proposed configuration. [ABSTRACT FROM AUTHOR]

This paper presents coupled electromagnetic (EM)–thermal modelling of the steady-state dynamic performances, such as torque speed curve and the efficiency map, for surface-mounted permanent magnet machines. One important feature of such a model is that it considers the demagnetization caused by magnet temperature rise at different rotor speeds. EM-only simulations, which often assume that the machines operate under constant temperature, have been widely used in the literature. However, the interaction between EM and thermal performances could lead to very different dynamic performance prediction. This is because the material properties, e.g., magnet remanence, coercivity, and copper resistivity are temperature-dependent. The temperature rise within electrical machines reduces torque/power density, PM eddy current losses, and iron losses but increases copper loss. Therefore, the coupled EM–thermal modelling is essential to determine accurate temperature variation and to obtain accurate EM performances of electrical machines. In this paper, the coupled EM–thermal modelling is implemented for both modular and non-modular machines to reveal the advantages of the modular machine under different operating conditions. The results show that the modular machine generally has better dynamic performance than the non-modular machine because the introduced flux gaps in alternate stator teeth can boost both EM and thermal performance. [ABSTRACT FROM AUTHOR]

In order to accurately analyze the temperature distribution of a high-speed magnetic suspension amorphous motor, a multi-physical coupling method, including flow field, electromagnetic field and temperature field, is proposed. The electromagnetic loss obtained by electromagnetic analysis is directly mapped to the temperature field and input to the boundary conditions of the flow field for several coupled iterations. This paper compares the thermal analysis results of two different temperature rise calculation methods, analyzes the temperature distribution of magnetic suspension amorphous motor under different working conditions, and discusses the simulation results and the measured results. The error between the multi-field coupling simulation results and the experimental results is less than 10 °C, and the error of the traditional temperature rise analysis method is 30 °C, which verifies the superiority of the proposed coupling analysis method in improving the calculation accuracy of motor temperature rise, and has important significance for the accurate prediction of motor temperature rise in the design stage. [ABSTRACT FROM AUTHOR]

The PMSM (Permanent Magnet Synchronous Motor) is being studied a lot in traction motors for high efficiency and high performance. Usually, magnets containing rare earth elements are used. However, since rare earth elements are not suitable for future industries due to their limited reserves, many studies on magnets excluding rare earth elements are being conducted. Magnets excluding rare earth elements have a low coercive force and are vulnerable to irreversible demagnetization, so their design must be robust. Additionally, the design used for reducing the cogging torque, which is a major variable of traction motors, is also important. Therefore, in this study, a design process for reducing irreversible demagnetization and cogging torque is proposed. There are three methods for this process. The first one is the application of the tapering structure, and the second one is the tapering skew structure. The third one is the application of an asymmetric air hole. As a result of these methods, the target irreversible demagnetization ratio was satisfied and the cogging torque was reduced. This was proven through FEA (Finite Element Analysis) and verified by comparing and analyzing the experimental results and simulation results of actual manufacturing. [ABSTRACT FROM AUTHOR]

This paper presents a topology for the brushless operation of a wound-rotor synchronous machine based on the subharmonic excitation technique by using two sets of multi-pole windings on the armature as well as on the rotor. The armature windings consist of a four-pole three-phase main winding and a two-pole single-phase additional winding, responsible for the generation of fundamental and subharmonic components of magnetomotive force (MMF), respectively. The rotor contains four-pole field winding and two-pole excitation winding. From the generated air gap MMF, the additional winding is responsible for induction in excitation winding, which feeds DC to the field winding through a rotating rectifier without the need of brushes. Then, the interaction of the magnetic field from the main and the field windings produces torque. The proposed topology is analyzed using 2D finite element analysis (FEM). From the analysis, the generation of the subharmonic component of MMF is verified, which helps in achieving the brushless operation of the wound-rotor synchronous machine. Furthermore, the performance of the proposed brushless multi-pole topology is compared with the existing dual three-phase winding multi-pole topology in terms of current due to induction, output torque, torque ripples, and efficiency. [ABSTRACT FROM AUTHOR]

The development of the financial industry directly affects the sustainable competitiveness of a city and even an economic region, and the development of urban finance helps to enhance the sustainable competitiveness of a city. This paper firstly reviews the relevant theories of sustainable urban competitiveness and explains the impact mechanism of financial development on sustainable urban competitiveness in developing regions. It then draws on the data of 17 prefecture-level cities in Central China from 2006 to 2020. It uses quantitative research methods, such as principal component analysis and regression analysis, to analyse and study the factors of financial development that influence sustainable urban competitiveness, thus realising the research purpose of enhancing sustainable urban competitiveness. After an in-depth analysis, the paper draws the following conclusions: (1) financial development is conducive to improving the sustainable competitiveness of a city in developing regions; and (2) the local government should focus not only on expanding the scale of financial development, but also on the quality of financial development, adjusting the financial structure, improving financial efficiency, and actively promoting the opening of financial markets and innovation of financial products. [ABSTRACT FROM AUTHOR]

Featured Application: Stand-alone wind power generator. In this paper, a novel mechanical flux-weakening design of a spoke-type permanent magnet generator for a stand-alone power supply is proposed. By controlling the position of the adjustable modulator ring mechanically, the total induced voltage, i.e., the amplitude of the back EMF vector sum can be effectively adjusted accordingly by the modulation effect. Consequently, the variable-speed constant-amplitude voltage control (VSCAVC) with a large speed range can be achieved. Compared to the electrical flux-weakening method, the mechanical flux-weakening method is easier to operate without the risk of PM demagnetization. The analytical model is presented, and the operation principles are illustrated. To analyze the performance of different combinations of stator/rotor pole pairs, four cases are optimized and analyzed using the finite element method for comparison. The characteristics of VSCAVC are analyzed. [ABSTRACT FROM AUTHOR]

Brushless synchronous homopolar machines (SHM) have long been used as highly reliable motors and generators with an excitation winding on the stator. However, a significant disadvantage that limits their use in traction applications is the reduced specific torque due to the incomplete use of the rotor surface. One possible way to improve the torque density of SHMs is to add inexpensive ferrite magnets in the rotor slots. This paper presents the results of optimizing the performances of an SHM with ferrite magnets for a subway train, considering the timing diagram of train movement. A comparison of its characteristics with an SHM without permanent magnets is also presented. When using the SHM with ferrite magnets, a significant reduction in the dimensions and weight of the motor, as well as power loss, is shown. [ABSTRACT FROM AUTHOR]

This paper presents an evaluation of the current technologies and future requirements of electrical machine in automotive. First, a comparative of ten different electrical machines based on the market available electrical vehicles and hybrid electrical vehicles is made. The aim of the comparison is to evaluate the different electrical machine topologies, structure, operation conditions, and performance. The future design requirements of electrical machine in automotive are presented and several state-of-art electrical machine design techniques have been explored and studied by employing them in the compared ten machines. The conclusion of this work shows that permanent magnet topologies have the highest performance among the different electrical machine topologies and have the potential to meet the future requirements. In addition, aggressive cooling methods, i.e., spray, dripping, semi- or fully flooded, are needed to allow electrical machines to operate with the required power density target. Finally, the design to recycle concept shows the potential to be implemented in future electrical machines with little or no sacrifice of the performance. [ABSTRACT FROM AUTHOR]

One of the pronounced features of the multi-phase machines compared to the conventional three-phases machine is their high-fault capability. This merit is quite important as it contributes to minimising the number of interruptions in industrial operations. This paper introduces two new Space Vector Pulse Width Modulation Techniques (SVPWM) to be used with the Field Oriented Control (FOC) strategy under two phases failure of the five-phase motor drives. The first SVPWM technique can be used if the failure happens to the adjacent phases while the second one is used in the cases that the failure happens to non-adjacent phases. The proposed modulation techniques consider the modifications of the remaining healthy stator currents of the five-phase motor under the failure of the two adjacent phases and non-adjacent phases to maintain the torque producing Magneto Motive Force (MMF) and hence maintain the speed. This will enhance the reliability of the whole drive system. Simulation results illustrate the capability of proposed new SVPWM techniques to maintain the torque ripple less than 3.6% and 3.4% post the failure in adjacent phase and non-adjacent phases respectively. [ABSTRACT FROM AUTHOR]

Multiphase electric machines are increasingly used in various industries and for electromobility. Complex systems have been developed for the control and powering of multiphase machines, which require verification. The quality of control and the power supply of electric machines is usually evaluated by analyzing various electrical parameters. On the other hand, taking into account the fact that a motor is an electrical-mechanical object, its full diagnostics should also include the analysis of vibration signals to verify the operation of the motor as a mechanical device. In this paper, a sensorless control algorithm was studied and applied to a 5-phase induction motor. Various scenarios were considered; in particular, the operation of the studied motor in the absence of one or two phases and in the case of the introduction of the third harmonic to increase the torque was analyzed. In the scenarios considered, the motor was connected to another machine and operated with no load as well as with a preset load. The results obtained were analyzed in the time and frequency domain and were related to the standards used. [ABSTRACT FROM AUTHOR]

Nanocrystalline powders from the Permalloy family, Ni75Fe25, Ni79Fe16Mo5, and Ni77Fe14Cu5Mo4, were obtained by mechanical alloying starting from elemental powders. All compositions were milled for up to 24 h in a high-energy planetary ball mill. The powders were single phase and nanocrystalline as determined by X-ray diffraction studies, with larger flatted particle sizes for Ni75Fe25 (about 400 μm) and Ni77Fe14Cu5Mo4 (about 470 μm), and smaller particle sizes for Ni79Fe16Mo5 (about 170 μm). The homogeneity of the samples was verified by energy-dispersive X-ray spectroscopy (EDX). Soft magnetic composites were obtained by adding 3% of Araldite to the powders, followed by compaction at 700 MPa, and then polymerization. A very good powder covering by the polymer layer was proven by EDX elementals maps. The influence of composition change on the electrical resistivity of the compacts was studied. Hysteresis measurements in static and dynamic fields of up to 10 kHz were recorded, showing the influence of composition and particle size on the compact properties. [ABSTRACT FROM AUTHOR]

In order to solve the excitation problem of elevator traction permanent magnet synchronous motors (PMSMs), a new high-order sliding mode flux observer based on a hybrid reaching rate is proposed under the background of industrial engineering to detect loss of excitation faults in real time. Firstly, a new high-order sliding mode flux observer is designed to solve the problem of the traditional sliding mode observer not being able to accurately detect the loss of excitation fault when the load resistance changes. Then, based on the sliding mode variable structure equivalent control principle, a PMSM flux estimation formula is established. The sinusoidal input function replaces the traditional symbolic process, and a mixed approach law is designed to replace the constant speed approach rate. The adaptive adjustment of the boundary layer of the sinusoidal input function is realized through a fuzzy control system, which effectively suppresses the chattering problem caused by the sliding mode variable structure and improves the observation accuracy of rotor position. The stability of the system is verified by Lyapunov's second method. MATLAB/Simulink is used to build the simulation model of the PMSM control system with the new sliding mode observer, and the simulation results are compared with those of a traditional sliding mode observer. The results show that compared with the conventional observer, the new sliding mode observer can track the rotor position quickly, and the system has better anti-interference abilities and stability. Finally, the feasibility and effectiveness of this method are verified via simulations and experiments. [ABSTRACT FROM AUTHOR]

The need of compact machines increased in recent years due to increases in raw materials' price. Hence, many studies are currently being conducted on high-speed challenges to propose an optimal design methodology. AC losses in windings are often not included in the optimization process and are treated in post-processing by choosing a suitable conductor's diameter to mitigate skin and proximity effects. This paper presents an optimization and design methodology for high-speed electric machines considering these losses, using models with an interesting trade-off between computation time and accuracy, which is helpful for large-scale optimization, in which more than 9,600,000 machines are evaluated. Optimizations are conducted on 100 kW high-speed one-layer V-shaped interior permanent magnet synchronous machines, widely used in vehicles thanks to their high power density, based on the specifications of the Peugeot e208, for different values of pole pairs and maximum speed. The influence of lamination thickness, fill factor, and maximum current density on the optimal design is also investigated. This paper concludes the utility of increasing speed to achieve high power density and proposes best alternatives regarding automotive constraints. Results show that the number of pole pairs is not always a key parameter in obtaining the lowest volume, especially at high speed. [ABSTRACT FROM AUTHOR]

In this paper, a new hybrid excitation drive motor (HEDM) was proposed to solve the problem of an uncontrollable magnetic field of a permanent magnet motor. The rotor part of the motor was composed of a combined magnetic pole permanent magnet rotor and a brushless electric claw rotor, in which the combined magnetic pole permanent magnet rotor has a parallel magnetic circuit structure. According to the characteristics of the parallel rotor structure, the equivalent magnetic circuit model was established, and the no-load leakage flux coefficient of the claw pole rotor was calculated. The Taguchi method was used for objective optimization of the permanent magnet rotor structure. The distortion rate of no-load back electromotive force (EMF) was taken as the first optimization goal; the cogging torque and the average torque were taken as the second optimization goal; and the torque fluctuation coefficient was a constraint condition. The optimal parameter matching under the mixed horizontal matrix was obtained. The parameters of the claw pole were optimized by using the method of uniform variables, and the dimension parameters of the motor were obtained. Finite element analysis and prototype tests were carried out for the optimized motor structure. The rationality and feasibility of the new HEDM as a vehicle motor were verified, which provided a possibility for the application of the new energy vehicle drive motor field. [ABSTRACT FROM AUTHOR]