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A. Deihimi
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ABSTRACT: In the magnetic equivalent circuit (MEC) method, a set of lumped permeance elements is used to model the nonlinear magnetic field in electromagnetic devices. The accuracy of the method depends on the geometric shape and size of flux tubes associated with permeance elements as well as the number of elements, particularly for modeling highly saturated regions. Although it is possible to suggest nearly correct graphical shape of tubes in these regions, the actual cross section of such flux tubes is difficult to determine. This paper examines the problem and presents a technique, here called flux ratio criterion (FRC), which is helpful to determine the cross section of each flux tube in highly saturated regions during the solution process of nonlinear equations of the magnetic circuit The proposed technique is used to predict the static characteristics and dynamic performance of a switched reluctance machine (SRM). The results are compared to those obtained from measurement, conventional MEC and FE methods. As a conclusion, the most accurate results are achieved by proper choice of number of elements discretizing the flux into several flux tubes as well as connecting adequate number of elements of proper cross sections in series in highly saturated regions.
Optimization of Electrical and Electronic Equipment, 2008. OPTIM 2008. 11th International Conference on; 06/2008
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A. Deihimi
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ABSTRACT: Design of Switched Reluctance Machines (SRMs) for high-performance drive applications depends inherently on characteristics of other drive components. Such a dependency complicates the design problem, and increases the search-space dimensions. The control strategy which chiefly dictates converter topology and control unit commanding approach has the greatest effect on SRM operation. This paper presents novel SRM synthesis algorithms based on the current PWM control strategy, and shows how to use them in SRM design optimization. Furthermore, as drives in most of applications may operate normally at a large number of operating points, it will be addressed how to optimize the SRM design in terms of overall drive performance at all the operating points.
Optimization of Electrical and Electronic Equipment, 2008. OPTIM 2008. 11th International Conference on; 06/2008
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ABSTRACT: Solving the thin-wire electric field integral equation (EFIE) by the multiresolution wavelet expansion method involves a time-consuming double numerical integration for each nonzero element of the moment matrix which in turn can outweigh the advantages of achieving a sparse matrix. To speed up the matrix fill process in wavelet-based moment method codes, first, the triangular scaling functions of a nonorthogonal piecewise liner wavelet at the finest spatial resolution are appropriately replaced by sinusoidal dipoles for which mutual impedances are available in closed-form analytical expressions. The fast wavelet bases transform is then exploited to effectively transfer the resultant matrix equation to multiresolution wavelet domain. Numerical results obtained by the compactly supported semi-orthogonal linear B-spline wavelet demonstrate dramatic reduction of the overall solution time without any degradation in the accuracy of the final solution
IEEE Transactions on Magnetics 05/2006; · 1.36 Impact Factor
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ABSTRACT: The design optimization of industrial motor drives with restricted regard to a nominal operating point has never satisfied engineering concerns over optimal drive performance at other operating points. This is especially the case, where the drive operation is not concentrated on a few operating points. Therefore, drives as well as drive components, such as machine, electronic converter and control system, have to be designed to present an optimal performance at all considered operating points. This paper describes a design optimization methodology for turn-off snubber circuits used in switched reluctance (SR) drives. The goal of the optimization process is to minimize the switching losses of the electronic converter at all operating points corresponding to an enclosed region in the torque-speed plane. The paper shows the better converter efficiency in the presence of the optimal turn-off snubber. Moreover, a converter loss evaluation procedure is proposed. The accuracy of this procedure is verified by comparison of the predicted results with those obtained from the Simplorer package and experiments. Because separately measuring of the converter switching losses for a running drive is not practical, the effectiveness of the design optimization methodology is then investigated based on the proposed loss evaluation procedure.
Power Electronics Specialists Conference, 2004. PESC 04. 2004 IEEE 35th Annual; 07/2004
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ABSTRACT: This paper presents a general nonlinear magnetic equivalent circuit model of a switched reluctance machine (SRM) that includes
all possible flux paths in 2-D view of the machine, taking into account mutual coupling between phases and multiphase excitation.
The model can be used to predict the performance of the machine with short or full pitched winding in static and dynamic regimes.
Therefore, it is a simple analysing tool for finding the best configuration of SRM in computer-aided design and optimal design.
A novel technique is employed to model the lumped elements of stator and rotor poles, and a new representation of the rotor
core is introduced. Also, a general numerical matrix procedure is developed to calculate the total machine torque, and an
approximate analytic alternative is presented. Inclusion of the rotor skew in the new model is described, and the accuracy
of the model is verified by comparison of the simulation results with those obtained by the finite element method and measurements.
Electrical Engineering 01/2002; 84(3):143-158. · 0.40 Impact Factor
