共查询到20条相似文献,搜索用时 15 毫秒
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《IEEE transactions on magnetics》2008,44(10):2299-2309
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《IEEE transactions on magnetics》2008,44(9):2195-2203
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The paper presents a simplified analytical method to design a small two-pole slotless brushless dc motor. Using only a few approximations, the motor analytical model is formulated to generate a system of equations. The system can be solved analytically, producing a motor design for given specifications. The method is used to design a motor with the specifications 150 W, 10 000 rpm, and 18 V 相似文献
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Minimizing Thrust Fluctuation in Moving-Magnet Permanent-Magnet Brushless Linear DC Motors 总被引:1,自引:0,他引:1
We present the results of our research on the factors that cause thrust fluctuation in moving-magnet-type permanent-magnet brushless DC linear motors (PMBLDCLM). We combined Fourier transforms and finite-element models to obtain the power spectra of three components of the detent force. We developed a method of optimizing magnet width to minimize the detent force on the basis of harmonic analysis. To verify this method, we designed several motor models with different magnet widths and analyzed them by finite-element methods. The calculations and experimental results prove that thrust fluctuation of the motor can be effectively reduced with our method 相似文献
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《IEEE transactions on magnetics》2009,45(12):5383-5387
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《IEEE transactions on magnetics》2009,45(4):2023-2031
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《IEEE transactions on magnetics》2008,44(8):2074-2081
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We have studied a few simple demagnetization models, which are quick and easy to implement in finite-element calculations, and compared them with measured recoil behavior of Nd-Fe-B magnet material, also using a hysteresis model for comparison. The models are used to estimate post-demagnetization performance of an overloaded surface magnet synchronous machine. Two of the simple models, the sloped linear model and the exponent function model, give the most accurate results without significantly increasing the computation time. 相似文献
11.
A Quantitative Comparative Analysis of a Novel Flux-Modulated Permanent-Magnet Motor for Low-Speed Drive 总被引:1,自引:0,他引:1
A novel low-speed flux-modulated (FM) permanent-magnet (PM) motor that breaks the traditional design rule, which stipulates that the number of stator pole pairs and the number of rotor pole pairs must be the same, is proposed. The FM motor has a special physical structure with iron segments in the air gap to modulate the magnetic field. In the design, the free space between adjacent stationary iron segments also acts as ventilating ducts to help improving the heat dissipation and ventilation of the motor. Its cogging torque is very small. In this paper, a rule for comparing the power density of electric motors is proposed. The performance of the FM motor is compared with those of a magnetic-geared PM motor, a traditional PM motor, and a fractional-slot PM motor by using magnetic field finite-element analysis. 相似文献
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Using Modular Poles for Shape Optimization of Flux Density Distribution in Permanent-Magnet Machines
《IEEE transactions on magnetics》2008,44(8):2009-2015
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《IEEE transactions on magnetics》2008,44(10):2317-2323
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We present strength and fatigue characteristics of materials suitable for high-speed motor rotors used in centrifugal compressors. We established that laser shock peening efficiently produces deep compressive stresses and significantly decreases the fatigue crack growth rate in titanium alloys. For titanium alloys of all types considered, the microstructure of the heat-affected zone after laser treatment significantly differs from the microstructure of the original alloy. Grain coarsening occurs both in unalloyed titanium and in near-alpha, alpha–beta, near-beta, and metastable alloys. For practical applications, titanium alloys require additional heat treatment. In particular, aging and mechanical treatment are used for increasing strength characteristics. 相似文献
15.
Application of Schwarz-Christoffel Mapping to Permanent-Magnet Linear Motor Analysis 总被引:1,自引:0,他引:1
Several well-known analytical techniques exist for the force profile analysis of permanent-magnet linear synchronous motors. These techniques, however, make significant simplifications in order to obtain the magnetic field distribution in the air gap. From the field distribution, the force profile can be found. These widely used techniques provide a reasonable approximation for force profile analysis, but fail to give really accurate results in the sense of the exact shape of the force profile caused by effects that due to simplification are not fully included. To obtain the exact shape for the force profile in these cases, the computationally expensive finite-element method (FEM) is often applied. In this paper, an elegant semianalytical approach is presented to acquire the force profile. First, the magnetic field distribution in the air gap is determined by means of Schwarz-Christoffel (SC) mapping. The SC mapping allows a slotted structure of the machine to be mapped to a geometrically simpler domain for which analytic solutions are available. Subsequently, the field solution in the slotted structure can be determined by applying the mapping function to the field distribution in the simplified domain. From the resulting field distribution, the force profile is calculated by means of the Maxwell stress tensor. The results are compared with those from the commonly used equivalent magnetic circuit modeling and 2-D FEM software to demonstrate the accuracy which can be reached by application of the SC method. 相似文献
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《IEEE transactions on magnetics》2009,45(8):3145-3150
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《IEEE transactions on magnetics》2008,44(10):2324-2331
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We develop an analytical expression for predicting electromotive force (EMF) waveforms resulting from permanent magnets (PMs) in electrical machines. The expressions for the flux linkage are based on a volume integral over the magnet volume, rather than the usual surface integral over the coil. The proposed method consists of applying a virtual current in the coil of the machine and calculating the magnetic field generated inside the PM volume. The EMF waveform is obtained by taking the derivative of the flux linkage with respect to time. We present analytical expressions of the EMF for various PM shapes and Halbach magnetization patterns. We tested a total of four configurations of PMs, and the experimental waveforms confirmed the validity of the expressions obtained theoretically. 相似文献
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Finite-Element Analysis of the Magnetic Field and Electromechanical Parameters Calculation for a Slotted Permanent-Magnet Tubular Linear Motor 总被引:2,自引:0,他引:2
We have calculated magnetic field distribution and integral parameters for the slotted, five-phase, permanent-magnet tubular linear motor (PMTLM). We used a finite element (FE) model for the field analysis. We carried out the field analysis for different values of the exciting current and for variable mover position. To obtain experimentally the field distribution and its integral parameters, we developed and tested a physical model of the motor. We compared the calculation results with the measured ones and found a good conformity. 相似文献
20.
We present an analytical solution for the magnetic field, induced eddy currents, and the corresponding losses generated in the rotor of a slotless permanent-magnet (PM) motor. The field excitation is a current sheet placed at the stator interior surface. The solution is based on an analytical solution of the diffusion equation using double Fourier series and in the complex domain. The first and the second Fourier series correspond to the time and space harmonics, respectively. We have analyzed the effect of each time harmonic in detail, and verified the results with FEM software. 相似文献