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This paper aims to clarify the relationship between stator tooth shape and DC voltage fluctuation of a double salient hybrid excitation generator (DSHEG). It analyzes the asymmetrical characteristics of the magnetic circuit and inductance between each phase. The study aims to reduce voltage fluctuation by using a stator shape optimization scheme, which helps reducing inductance difference.

This paper opted for a method combined with theoretical analysis, simulation and experimental verification. The stator tooth optimization scheme is given based on theoretical asymmetrical analysis and Taguchi method. A series of two-dimensional finite element analysis simulation of different conditions are conducted. Two prototypes with different stator tooth shape are made and experiments are carried out.

The paper provides empirical insights into how the stator tooth shape influences the asymmetry of inductance and DC voltage fluctuation. Compensation adjustments to the stator tooth shape can narrow the inductance differences of each phase. It suggests that “LTL” shaped DSHEG has lower voltage ripple than “III” shaped DSHEG without sacrificing output power.

Because of the chosen research approach, the gap between magnets and stator and end effect are not considered. Errors exist between simulation and experimental results.

The paper includes implications for other “C” shaped tooth optimization. Study on phase asymmetry of the special machine can further improve quality testing and simplify control strategy.

This paper analyzes the asymmetry of DSHEG and proposes an optimized stator tooth shape to reduce DC voltage fluctuation.

The automotive industry extensively uses switched reluctance motors (SRM) because of their excellent performance. The main purpose of this article is to investigate the design of a particular type of SRM called doubly salient outer rotor switched reluctance motor (DSORSRM) for electric vehicle application in this paper.

Different configurations of DSORSRM motor such as long flux path SRM, reduced flux path mutually coupled SRM and short flux path SRM (SF-SRM) are considered for investigation. The best configuration based on average torque is selected for further investigation by conducting an electromagnetic analysis. Also, in the proposed design, laminating material with low iron loss and superior performance characteristics is selected by doing electromagnetic analysis for SRM with M19, M660-50D, M-19 and M800-100A non-oriented laminating core material. Because vibrations are produced in DSORSRM devices as a result of changing induction, a mechanical analysis was performed to estimate the natural frequencies of vibration and the amplitudes that may lead to acoustic noises.

SF-SRM configuration with three-phase, 12/10, 250 W, 48 V, 1,000 rpm is selected with the impact in the elimination of flux reversals and also has various salient features such as singly excited, no rotor windings, no permanent magnet, pure in construction and high starting torque. Still, this SRM suffers from vibration owing to changing induction. In lamination material selection, M19 is chosen as optimized material to obtain vibration reduction. Vibration analysis was performed for the optimized 12/10 SF-SRM with M19 lamination material, and the corresponding modes for the machine to operate with reduced vibration are analyzed. The current and speed characteristics of the prototype model for the DSORSRM motor are obtained and validated with finite element analysis (FEA) results.

The performed FEA result shows that the proposed DSORSRM with short flux path configuration produces a high average torque of 1.915 N m. The M19 lamination material gives a minimum iron loss of 9.056 W. The modal frequencies are estimated and validated with numerical equations.

Method of unaligned permeance determination for a doubly‐salient rectilinear airgap with infinite slot depth is used in order to cover a wider range of gap geometry. The results are arranged in a more convenient form than is available in the literature. A set of new correction factor curves for finite slot depth and taper are then obtained. These data can directly give the unaligned permeance of a rectilinear slotted geometry for given airgap proportions (t/λ and λ/g, where λ is the tooth pitch, t is the tooth width and g is the airgap length). A wide and useful range of airgap proportions are covered, the aim having been to encompass all geometries likely to be of practical importance.

Effect of slot depth on the evaluation of permeance in the aligned position for identically slotted rectilinear tooth geometry can be carried out using conformal transformations. Consequent increase of permeance is related to the airgap proportion ratios; tooth‐width to tooth‐pitch, t/λ; tooth‐pitch to airgap dimension, λ/g; and slot‐depth to slot‐d/s; through two intermediate parameters. Efficient search routine is used to find a suitable combination of these two parameters corresponding to given proportions of tooth and slot. For λ/g larger than 80 and d/s between 0.3 and 1, the effect of slot depth is negligible, but for λ/g equal to or less than 80 a family of permeance correction factor curves is obtained which may be used to correct for finite slot depth in permeance calculations based on infinitely deep slots. This effect is important in stepping and switched reluctance motors, particularly those with multiple teeth per stator pole.

Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines; reluctance motors; PM motors; transformers and reactors; and special problems and applications. Debates all of these in great detail and itemizes each with greater in‐depth discussion of the various technical applications and areas. Concludes that the recommendations made should be adhered to.

This paper briefly describes an approach to determine the optimum magnetic circuit parameters to minimize low speed torque ripple for switched reluctance (SR) motors. For prediction of the torque ripple, normalized data obtained from field solution and a neural network approach is used. Comparison of experimental results with computations illustrates the accuracy of the method. The optimization method is briefly described and some results are presented.

The purpose of this paper is to suggest a procedure which makes it possible to reduce the radial vibrations of doubly salient switched reluctance motors (SRMs).

An analytical method for the SRM radial vibration determination is first described. It is then extended to the active vibration reduction. An auxiliary winding equips the stator. The paper explains how the corresponding currents have to be adjusted to achieve a simple and robust control, with a special emphasis about the compatibility of the main and auxiliary supplies and about the reduction control principle. At last, an example of drastic noise reduction is presented.

The proposed method makes possible to define the theoretical vibration spectrum of SRM and thus it gives the major components to be reduced. The feasibility of automating the principle of active reduction is shown. The process of active reduction shows that a vibration component can be diminished by over 90 percent.

The active reduction is applied for reducing one component of the vibration spectrum. Future developments will focus on the simultaneous reduction of several components of vibration spectrum.

The method offers an automated process to reduce considerably the component of highest amplitude in the vibration spectrum.

The purpose of the paper is to model, analyze and control a new flux‐controllable stator‐permanent‐magnet brushless (PMBL) motor with skewed rotor.

A new flux‐controllable stator‐PMBL motor with skewed rotor is presented. The key of the proposed motor is to incorporate both direct current field windings and permanent magnets in the stator. By using a 2D multi‐slice finite element model, the electromagnetic performances such as flux linkage, self‐inductance and back‐EMF are obtained. To minimize the torque ripple, a vector control strategy is applied to the stator‐PMBL motor drive for the first time.

Some encouraging experimental results such as lower torque ripple and faster speed transients are achieved. It is shown that the three‐phase flux‐controllable stator‐PMBL motor, when properly designed and controlled, is an interesting candidate for traction drive systems especially for electrical vehicle operation.

The control method can also contribute the other type of stator‐PMBL machines to realize the low torque ripple.

The tractive force between two slightly overlapped steel teeth exhibits a remarkably linear relationship with m.m.f. over a considerable range of variables. This occurs despite complex and varying patterns of field at the tooth surfaces, with local flux densities approaching 3 Tesla. A theoretical explanation is not readily available. Results of a computational investigation are reported and analytical approaches considered.

The purpose of this paper is to propose a new outer‐rotor permanent‐magnet flux‐switching machine (ORPMFSM) for electric vehicle (EV) in‐wheel propulsion. The paper documents both the design procedure and performance investigation of this novel machine.

The topology and preliminary sizing equations of the ORPMFSM are introduced. The rotor poles are optimized, whilst the machine losses are particularly investigated, using 2‐D finite element analysis (FEA).

An ORPMFSM, with 12 stator poles and 22 rotor poles, is most suitable for the proposed EV application. The analytical sizing equations are quite efficient with a sufficient accuracy for the preliminary design. The optimal rotor pole width from the FEA results is nearly 1.3 times the original value which was proposed in early literatures. The efficiency of the proposed machine under rated load is slightly low, as a result of significant eddy current losses in the permanent magnets. The losses can be effectively suppressed with the technique of magnet segmenting. The predicted outstanding performance implies that by adopting magnet segmentation the proposed machine is a leading contender for EV direct drives.

The outer‐rotor structure of PMFSM was not addressed in early literatures. This paper provides designers with the technical background and an alternative candidate for the EV propulsion.