Добірка наукової літератури з теми "Winding-On-Teeth"

This paper presents a two-dimensional (2D) exact subdomain technique in polar coordinates considering the iron relative permeability in 6/4 switched reluctance machines (SRM) supplied by sinusoidal waveform of current (aka, variable flux reluctance machines). In non-periodic regions (e.g., rotor and/or stator slots/teeth), magnetostatic Maxwell’s equations are solved considering non-homogeneous Neumann boundary conditions (BCs). The general solutions of magnetic vector potential in all subdomains are obtained by applying the interface conditions (ICs) in both directions (i.e., r- and θ-edges ICs). The global saturation effect is taken into account, with a constant magnetic permeability corresponding to the linear zone of the nonlinear B(H) curve. In this investigation, the magnetic flux density distribution inside the electrical machine, the static/dynamic electromagnetic torques, the magnetic flux linkage, the self-/mutual inductances, the magnetic pressures, and the unbalanced magnetic forces (UMFs) have been calculated for 6/4 SRM with two various non-overlapping (or concentrated) windings. One of the case studies is a M1 with a non-overlapping all teeth wound winding (double-layer winding with left and right layer) and the other is a M2 with a non-overlapping alternate teeth wound winding (single-layer winding). It is important to note that the developed semi-analytical model based on the 2D exact subdomain technique is also valid for any number of slot/pole combinations and for non-overlapping teeth wound windings with a single/double layer. Finally, the semi-analytical results have been performed for different values of iron core relative permeability (viz., 100 and 800), and compared with those obtained by the 2D finite-element method (FEM). The comparisons with FEM show good results for the proposed approach.

In this research, we focus on development of a new configuration of magneto-rheological fluid (MRF) based clutch (MRC) featuring a tooth-shaped disc with multiple teeth acting as multiple magnetic poles of the clutch. The tooth-shaped disc is placed in a clutch housing composed of the left housing and the right housing. The inner face the housing also has tooth shaped features mating with the teeth of the disc through the working MRF. Excitation coils are placed directly on stationary winding cores placed on both side of the clutch housing. An air gap of 0.3 mm is left between the housing and the winding cores to ensure the housing can freely rotate against the winding cores. After the introductory part, configuration of the MRC is introduced and the transmitted torque of the MRC is derived. An optimization process to minimize the overall volume of the proposed clutch, which can generate a required maximum braking torque, is then conducted. The optimal results show that the overall volume of the proposed MRC is significantly reduced compared to a referenced conventional MRC (0.159 m3 vs. 0.295 m3). A prototype of the proposed MRC is fabricated for experimental works and good agreement between the experimental results and simulated ones is archived.

The paper considers valve motors with toothed windings with pole numbers 2, 4, 6, 8, the main dimensions of which correspond to the 6DVM 300 valve motor manufactured by JSC “Cheboksary electrical apparatus plant”. This approach allows us to evaluate the effect of the number of stator teeth on the electromagnetic moment and its harmonic composition. The three adjacent coils of the toothed windings in question belong to three different phases. The paper analyzes the MMF of the windings and magnets of the rotor. The distribution of magnetic induction in the gap, the EMF of the stator winding and the electromagnetic moment are found based on the method of the specific magnetic conductivity of the gap. It is shown that the MMF curve of the stator winding consists of two multipolar rectangles of unequal height and width. Due to the non-sinusoidal distribution of magnetic field sources and the jagged inhomogeneity of the air gap, the curves of the phase EMF of the stator winding are also significantly non-sinusoidal. It is found that with an increase in the number of poles (from 2 to 8 poles) of the stator winding, the maximum induction in the air gap decreases from level 1 to 0.75 Tl, the average value of the electromagnetic moment increases from 120 to 160 Nm, the amplitude of the phase EMF remains unchanged, and the maximum (height of the rectangle) of the MMF of the stator winding is reduced from 2000 to 500 A.

Abstract Electric vehicles (EVs) need a wide speed and torque range for their reliable operation and working. Switched reluctance motors (SRMs) offer several advantages like high life cycle, meager cost, simple construction, robustness, good speed characteristics, and fault-tolerance, making it a suitable motor drive for EV application. The selection of independent variables like dimensions, winding turns, make materials, the number of slots, and the shape of rotor and stator teeth is a cumbersome task as SRM performance is mainly dependent on these parameters. This paper describes the methodology for selecting these independent variables by evaluating the SRM performance for different shapes of rotor and stator teeth, with the different stator and rotor materials, by taking all the design constraints like winding resistance, turns, and the number of slots. The EV drive performance is evaluated for the chosen independent variables and analyzed using JMAG software for determining the efficiency, Torque, and speed responses for comparison and analysis to get the optimal design constraints of the independent variables of SRM.

Subdividing stator winding is a way to lower the DC link voltage value in electric drives and reduce the stress on motor insulation. Coupled windings sharing the same stator teeth are modelled in order to evaluate the link between voltages disparities and current ripple. This paper provides an assessment of current ripple rise in the subdivided windings compared to ordinary topologies through the use of a basic inductive model. A method for PWM-Induced current ripple and high-frequency loss estimation based on admittance measurements is developed and experimentally validated. The use of this subdivided structure does not induce more than a 10% rise of the PWM-induced current ripple compared to a standard winding structure.

Purpose This paper aims to develop models and simulations focused on the prediction of electromagnetic forces acting on the stator core of a synchronous machine. It contributes to the study of stator core vibrations. Design/methodology/approach An analytical model based on the rotating fields’ theory including the damper winding contribution was developed. Such model allows the comprehension of airgap magnetic field distribution and the consequent pressure distribution. Focus was given to the pressure sub-harmonics due to the usual fractional winding configuration of low speed machines. A comparative numerical model was also developed and applied to an example laboratory machine. Partial validation measurements were performed. Findings The paper provides the predicted electromagnetic forces and the relative influences of damper winding and teeth tangential forces on each pressure harmonic. It is shown by how much such effects can influence the amplitude of pressure sub-harmonics from a fractional stator winding. Research limitations/implications The performed validation measurements were based on the airgap field distribution, but the resulting core vibration at load was not measured. Therefore, researchers are encouraged to perform additional tests for improved validation. Practical implications The obtained models and results are of great importance for the design phase of new generators and for the diagnosis process of existing machines with core vibration problems. Originality/value As a contribution of this paper, the magnitude of indirect effect of tangential forces and the effect of damper winding are comparatively quantified for each pressure harmonic. The given approach contributes to the relative evaluation of these effects especially on the sub-harmonics from the fractional stator winding.

The effective optimization methods are needed to reduce the thrust ripple for the tubular flux-switching permanent magnet linear motor (TFSPMLM), which is significant for reducing the vibration, and improving the reliability. The auxiliary teeth and core bridge are set and analyzed for the bipolar and single-polar winding structures. On this basis, this paper focused on a new method of the secondary pole pitch fine-tuning which can overcomes the disadvantages of increasing the volume, decreasing the average thrust, adding the cost, and so on. The influences of tuning the secondary pole pitch on the average thrust and the thrust ripple for the different winding structure motors are calculated and analyzed. The conclusion can provide reference for the application of the method of tuning secondary pole pitch to the TFSPMLM for different background demands.

Purpose The purpose of this paper is to present an improved winding function theory (IWFT) for performance analysis of surface mounted permanent magnet (SMPM) motors, which can precisely and simultaneously consider the impacts of stator slotting, the winding distribution, the magnetic flux density within PMs because of the armature reaction, the PM magnetization angle and the magnetic saturation,. Design/methodology/approach To obtain this improved analytical model, the conformal mappings (CMs) are introduced to calculate the relative complex permeance of slotted air-gap, which is used to obtain the function of slotted air-gap length. The equivalent magnetizing current model is used to extract the equivalent winding function for each PM pole. For retaining the basic assumption of WFT, the magnetic saturation is also considered by a proper increase in the air-gap length in the front of the stator teeth. Findings A new hybrid analytical model (HAM) based on WFT is presented in this paper, which can simultaneously and accurately consider the effects of slotting, the magnetic saturation, the variation of PM operating point and the winding distribution. In fact, IWFT removes all the drawbacks of the conventional WFT. Moreover, IWFT is more user-friendly and faster than other analytical and numerical techniques. Practical implications The obtained HAM can be used for design, optimization and fault diagnosis in electric machines. Originality/value This paper presents a new HAM for accurate modeling the SMPM motors, which includes different considerations of electromagnetic modeling. This new HAM can also be used for modeling the other electric motors.

La machine à induction est considérée comme l'une des machines électriques les plus utilisées dans les applications industrielles en raison de sa structure ferme, de sa robustesse, de sa simplicité, de son coût raisonnable, de sa longue durée de vie et de sa grande fiabilité. La machine à induction multiphasée, en particulier une machine à six phases, est une solution judicieuse pour augmenter la fiabilité par rapport à une machine à induction triphasée pour des applications telles que les véhicules électriques. L'augmentation du nombre de phases sur la machine peut entraîner une baisse de capacité en cas de perte d'une ou plusieurs phases. En outre, la configuration multiphasée offre d'autres avantages, tels qu'une capacité de gestion de puissance élevée en divisant la puissance requise entre les phases, des pulsations de couple réduites, des pertes de cuivre de stator réduites et des courants harmoniques de rotor réduits. Une autre solution pour améliorer les performances de la machine à induction consiste à utiliser un enroulement concentré car il présente de nombreux avantages tels que l'extrémité des spires plus courte sans chevauchement, une capacité de tolérance de panne plus élevée et une procédure de fabrication plus facile. Cependant, le principal inconvénient du bobinage concentré est la densité de flux d’entrefer de faible qualité. Compte tenu de l'inconvénient mentionné ci-dessus, l'application d'un enroulement concentré sur des moteurs à induction détériore considérablement leurs performances, ce qui rend inefficaces les avantages du bobinage concentré. Dans ce travail de recherche, l'objectif principal est d'améliorer les performances des moteurs asynchrones à six phases à enroulements concentrés. À cette fin, un nouveau schéma d'enroulement concentré réalisable, à savoir un enroulement pseudo-concentré, est proposé en utilisant une analyse de la fonction d'enroulement, qui a un harmonique fondamental plus élevé de la densité de flux d'entrefer par rapport aux enroulements concentrés conventionnels. L'utilisation de l'enroulement pseudo-concentré au lieu de l'enroulement conventionnel améliore considérablement les paramètres de performance du moteur à induction à six phases tels que la puissance de sortie, le rendement et le facteur de puissance. Pour améliorer encore les performances du moteur, un nouveau moteur à induction à six phases optimal équipé de l'enroulement pseudo-concentré est conçu et fabriqué en tenant compte des caractéristiques d'enroulement telles que l'extrémité d'enroulement plus courte et l'harmonique fondamental inférieur de la densité de flux d'entrefer par rapport à la distribution de l’enroulement conventionnel. Les résultats de performance du moteur montrent que le moteur à induction à six phases équipé de l'enroulement pseudo-concentré peut avoir des paramètres de performance élevés même par rapport au moteur équipé de l'enroulement distribué. Compte tenu des faits précités, il semble que l'utilisation d'un moteur à induction équipé du bobinage pseudo-concentré puisse être une solution appropriée pour une application de véhicule électrique. Pour en savoir plus, un moteur à induction à six phases à rotor extérieur équipé du bobinage pseudo-concentré est conçu et optimisé pour les véhicules électriques légers de faible puissance. Comme prévu, le moteur à induction à six phases à rotor externe optimal fabriqué fournit des performances acceptables pour une application dans la roue
Electrical Machine is an important research area in electrical engineering with numerous industrial applications. Induction machine is considered as one of the most employed electrical machines in industrial applications because of its firm structure, robustness, simplicity, reasonable cost, long lifetime, and high reliability. Multiphase induction machine, especially the six-phase one, is a sensible solution to increasing reliability compared to a three-phase induction machine for applications such as an electric vehicle. Increasing the number of phases on the machine can result in the ride through capability in case of loss of one or more phases. Furthermore, the multiphase configuration provides other advantages, such as high power-handling capability by dividing the required power between phases, reduced torque pulsations, reduced stator copper losses, and reduced rotor harmonic currents. Another solution in the way of improving induction machine performance is using concentrated winding because it has many advantages such as shorter non-overlapping end turns, higher fault-tolerant capability, and easier manufacturing procedure. The main drawback of concentrated winding, however, is its low-quality air gap flux density, which usually limits the winding application to permanent magnet synchronous machines. Considering the aforementioned drawback, applying concentrated winding to induction motors deteriorates their performances significantly, which renders the concentrated winding advantages ineffective. In this research work, the main goal is to improve the performance of the six-phase induction motors with concentrated windings. For this purpose, a new feasible concentrated winding layout, namely pseudo-concentrated winding, is proposed using winding function analysis, which has a higher fundamental harmonic of the air gap flux density compared to the conventional concentrated windings. Using the pseudo-concentrated winding instead of the conventional one enhances the performance parameters of the six-phase induction motor such as output power, efficiency, and power factor significantly. To enhance the motor performance, even more, a new optimum six-phase induction motor equipped with the pseudo-concentrated winding is designed and fabricated considering the winding features such as shorter end winding and lower fundamental harmonic of air gap flux density compared to the conventional distributed winding. The performance results of the motor show that the six-phase induction motor equipped with the pseudo-concentrated winding could have high-performance parameters even compared to the motor equipped with the distributed winding. Considering the aforementioned facts, it seems that using an induction motor equipped with the pseudo-concentrated winding can be an appropriate solution for electric vehicle application. To investigate more, an outer rotor six-phase induction motor equipped with the pseudo-concentrated winding is designed and optimized for light-duty low-power electric vehicles. As expected, the fabricated optimum outer rotor six-phase induction motor provides acceptable performance for the in-wheel application. In this research work, a novel pseudo-concentrated winding is introduced with better magnetic characteristics compared to the conventional concentrated windings, which allows applying it to the induction motors without having a noticeable performance drop compared to the distributed winding. The pseudo-concentrated winding has a lower air gap flux density amplitude compared to the distributed winding; therefore, for using this winding layout in induction motor application, a new stator lamination should be designed considering the magnetic characteristics of the pseudo-concentrated winding to achieve acceptable performance parameters

Marital unhappiness is a persistent theme of the Holmes stories, from the first (A Study in Scarlet) to several of the last (‘The Adventure of the Retired Colourman’ and ‘The Adventure of the Veiled Lodger’, both published in 1927). A Study in Scarlet begins as a detective story but its backstory is, as we have seen, a melodrama of forced marriage and domestic tyranny. ‘A Case of Identity’ concerns a courtship that is an elaborate deception, and the story opens with a digression on the ‘Dundas separation case’. This is reported in a newspaper as a ‘husband’s cruelty to his wife’, prompting Watson to claim that he knows the details without even reading the article: ‘There is, of course, the other woman, the drink, the push, the blow, the bruise, the sympathetic sister or landlady. The crudest of writers could invent nothing more crude.’ However, Holmes has investigated the case and reveals that it is actually more unusual: ‘The husband was a teetotaller, there was no other woman, and the conduct complained of was that he had drifted into the habit of winding up every meal by taking out his false teeth and hurling them at his wife’ (Adventures, 31).

Measurements of the dynamic and acoustic behavior of a commercial electric motor stator are presented. An Allis-Chalmers motor stator core, before and after winding and potting, was excited with drives on the teeth in tangential (circumferential and axial) and radial directions. The vibration response was decomposed into its circumferential harmonics and modes of vibration. The core was mounted in a sturdy, asymmetric housing, and showed significant harmonic character. The high circumferential order ring modes of the bare stator are limited to frequencies below those of the fundamental modes of the stator teeth. When the teeth are wound and potted, however, the ring modes resemble those of contiguous cylindrical shells, increasing in frequency with mode order. Also, the vibration response of the stator decreases significantly when it is wound and potted, particularly for drives tangential to the teeth. In spite of the reductions, drives tangential to the teeth still cause vibration comparable to, and sometimes higher than, that induced by radial tooth drives.