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A 2D direct-drive, low cost, easy to manufacture machine based on switched reluctance principle for industrial applications is proposed. This motor consists of the following major components: 1) aluminum base; 2) six laminated silicon-steel slots with coils; 3) two pairs of supporting mechanical slides holding the moving platforms; and 4) optical encoders to detect and feedback its position information.
This paper proposes a novel structured PM type stepping motor with claw-poles and analyze the magnetic characteristics using 3-D FEA taking into account the magnetization distribution of PM in magnetizing yoke. The simulation and experimental results show the proposed model has a good structure for the miniaturization. In addition, the design and manufacture of a novel structured PM type stepping...
This study investigates the dynamic characteristics of synchronous reluctance motor (SynRM), with segmental rotor structure, using finite element method in which the moving mesh technique is considered. The focus of this paper is the sensorless vector control parameters estimation of SynRM under saturation and iron loss. Extensive experimental work has been conducted to verify the accuracy of proposed...
This paper presents the results of a finite element (FE) analysis carried out to study the effects of rotor pole arc variation and rotor pole tapering on the performance of the DSPM motor.
This paper proposes a simple method to take into account the influence of end-effect on flux-linkage and back-emf in both flux-switching permanent magnet (FSPM) and doubly-salient permanent magnet (DSPM) machines on the base of 3-D finite element analysis (FEA). A leakage factor kend is defined to scale the grade of the influence of end-effect on PM machines.
Switched reluctance motor (SRM) has simple structure with a winding only on the stator and not on the rotor. The costs are lower than other motors due to its simple construction. It is easy to implement a high speed drive system and both the torque and efficiency of the unit volume are highly superior to all others. The simplest excitation strategy for the SRM is generally described by three excitation...
Recently, high-speed centrifugal turbo-compressors have been under intensive research and development. Since, compared to conventional compressors, high-speed centrifugal compressors have numerous qualities such as simple structure, light weight, small size, and high efficiency, etc. In order to maintain the mechanical integrity of a high-speed permanent magnet (PM) machine rotor intended for high-speed...
One of the main challenges in magnetic recording is to obtain a sufficient high thermal stability and at the same time a good writeability of the media. Recently, composite media and exchange spring media were proposed in order to shift the problem of writeability to higher areal densities. A similar concept can be applied to a recently proposed recording media called percolation media. In this paper,...
Driven by customer's demand, small sized mobile phones are realized due to latest development in electronics. For acoustic parts such as microspeakers and dynamic receivers, however, size reduction is relatively difficult due to their mechanical characteristics. An integrated device (microspeaker and dynamic receiver within one structure) has been developed to realize efficient size reduction. In...
This paper presents the effect of the non-uniform air-gap on the various characteristics of a 6/4 doubly salient permanent magnet motor (DSPM). Three important cases among the air-gap non-uniformities namely: (i) relative eccentricity between stator and rotor axes; and (ii) concentricity error on one-half and both halves of the rotor (elliptical rotor) have been analyzed for a 6/4-DSPM using the 2D...
In this paper, finite element modelling is used to simulate the perpendicular magnetic recording process with micromagnetic considerations. The simulation consists of a full-sized shielded-type head with current coil, a voronoi granular media and soft magnetic underlayer.
Incorporating magnetic materials into integrated-circuit inductors is an active area of research, offering higher inductance devices with smaller area. However, eddy current and spin dynamic losses in magnetic materials can hurt their performance. Here we analyze magnetic toroids as one candidate for IC inductors, utilizing a commercially available 3D electromagnetic FEM solver (Ansoft HFSS) that...
This paper presents a new semi-analytical method for computational electromagnetics. Today, the usual electromagnetic field simulation codes are mainly based on the finite element method (FEM). FEM uses the piecewise low order polynomials to approximate different kind of solution functions. The particular nature of a given problem is not considered, which greatly enhances the method's applicability...
This paper presents the effect of the non-uniform air-gap on the various characteristics of a 6/4 doubly salient permanent magnet motor (DSPM). Three important cases among the air-gap non-uniformities namely (i) relative eccentricity between stator and rotor axes, (ii) concentricity error on one-half and both halves of the rotor (elliptical rotor) have been analyzed for a 6/4-DSPM using the 2-D finite...
There has been intense research effort to increase the magnetoresistance (MR) of current-perpendicular-to-plane (CPP) spin valve, so as to maintain the high rates of areal density growth of magnetic media platters of the hard disk towards 1 Tbit/in2 and beyond. It has been proposed recently that MR can be increased with the insertion of ferromagnetic or half-metalic layers into the basic CPP spin-valve...
The finite element-analytical method (FEAM) is newly proposed and implemented for analysis of practical machines with free rotation. A new analytical solution of the airgap region will be derived, which can naturally couple with the FEM equations of both the stator and rotor regions. The proposed FEAM will be verified by comparing with both FEM and experimental results based on practical PM brushless...
In this paper, a method for predicting the electromagnetic vibration of PM brushless motors is presented. It calculates the electromagnetic force on individual stator teeth by the Maxwell stress method, based on 2-D finite element analysis of the electromagnetic field. The resulting radial force contour is then used in an analytical shell model to predict the stator vibration. The method has been...
A magnetic circuit model is developed for surface-mounted permanent magnet synchronous motors and simple analytical expressions of the average flux densities within the air gap and the parameters, such as open circuit EMF is derived. To verify the accuracy of the proposed model, 2D finite element analysis (FEA) is conducted for the model motor.
A generalized design procedure for a 70 W, 350 rpm axial-flux permanent magnet brushless DC (PM BLDC) motor having stator sandwiched between two permanent magnet rotors is presented. Based on the expressions for the torque and back emf, the output equation for an axial-flux PM BLDC motor, is derived. The optimized ratio of outer diameter to the inner diameter is used to derive the sizing equation...
The rotation of radial positioned magnets over a thin aluminum sheet or ladder guideway induces currents in the guideway that can simultaneously create thrust and lift forces. The uses of a flat split-guideway topology can also generate guidance forces when offset from the center. The magnetic rotor that creates these forces has been termed an electrodynamic wheel (EDW) and maybe useful for realizing...
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