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ABSTRACT: This letter proposes a two-stage approach to the open problem of establishing state-space formulation of 2D frequency transformation for 2D digital filters. In the first stage, formulation of generating a 2D state-space representation that is not in the standard form of a Roesser model will be derived, while in the second stage, the desired state-space formulation to generate a 2D Roesser state-space representation will be established based on the results obtained in the first stage by utilizing certain linear transformation. Moreover, it will be seen that the proposed formulation includes the formulation of 1D frequency transformation for 2D digital filters given by Koshita and Kawamata as a special case, and thus can be viewed as a natural generalization of their result. Numerical examples are given to illustrate the effectiveness of the proposed formulation.
IEEE Signal Processing Letters 01/2008; · 1.39 Impact Factor
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ABSTRACT: In this paper, a state-space formulation of 2D frequency transformation for 2D digital filters was derived. The obtained state-space formulation includes the well-known formulations of 1D frequency transformation for either 1D filters or 2D filters as special cases, and thus can be viewed as a natural generalization of these existing results to the general 2D case. A non-trivial example is given to illustrate the effectiveness of the proposed formulation.
Multidimensional (nD) Systems, 2007 International Workshop on; 07/2007
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ABSTRACT: A stepping motor has a concentrated stator winding and is usually driven by a pulse-shaped excitation voltage. Therefore, torque pulsation exists during rotation in principle. Meanwhile, various Vernier motors with low pulsation are being developed. For the HB-type Vernier motor, the authors derived a voltage equation and a torque formula by substituting magnetized sections with equivalent coils for analysis. This paper describes the analytical technique and compares the theoretical value of the pull-out torque with the measured value from the viewpoint of validation of the analytical technique. Using this analysis, a voltage equation and a torque formula similar to those for a general synchronous machine were obtained. To validate the analytical technique, the authors fabricated a test motor and measured its pull-out torque. It was confirmed that the calculated pull-out torque values matched the measured values quite well. Therefore, the pull-out torque can be calculated accurately by just acquiring the synchronous reactance and induced electromotive force. In a laboratory, even if only the synchronous reactance and induced electromotive force are acquired by the finite element method, the pull-out torque can still be calculated easily at high speeds and applied to the optimum design.
Electric Machines & Drives Conference, 2007. IEMDC '07. IEEE International; 06/2007
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ABSTRACT: Unlike the ID case, it is not always possible to find a minimal state-space realization for a general 2D filter/system except for some particular categories. In the article, the possibility of minimal Roesser model realization for a class of 2D filters, which does not belong to the clarified categories, is explored. A constructive realization procedure is first proposed, which can be viewed as a kind of generalization of the well-known 1D realization approaches. Based on the proposed procedure, minimal realization is constructed for the 2D filters with unit coefficients. Then, a sufficient existence condition for the minimal realization of the considered class of 2D filters with arbitrary coefficients is derived, and the corresponding minimal realization is obtained. Illustrative examples are presented to show the details and effectiveness of the proposed approach.
Electrical Machines and Systems, 2005. ICEMS 2005. Proceedings of the Eighth International Conference on; 10/2005
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ABSTRACT: This paper discusses the difficult problem of synthesis of stable stabilizing compensators for linear multidimensional (nD) single-input single-output (SISO) systems by exploiting existing results on stability tests. Firstly, we give an analytic expression for the class of stable stabilizing compensators when the plant is restricted to be a first-order 2D system and the compensator is a constant. We then briefly discuss how to generalize this result to other low order nD systems with low order stable stabilizing compensators. Two examples are illustrated.
Control and Automation, 2005. ICCA '05. International Conference on; 07/2005
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ABSTRACT: The purpose of this paper is to establish a new constructive procedure for realization of 2D systems by Fornasini-Marchesini second (F-MII) local state-space model which can further reduce the order of the resultant realization to about half of that obtained by the procedure given recently by the authors. Nontrivial illustrative examples are given.
Control, Automation, Robotics and Vision Conference, 2004. ICARCV 2004 8th; 01/2005
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ABSTRACT: The purpose of this paper is to develop an analytic way for designing optimal PI-controllers for interval plant family, in the sense that the coefficient intervals of the plant is maximized. It will be shown that the optimization problem can be formulated in terms of an eigenvalue minimization problem of matrix pairs of the form (H(h 0 , g 0 ), H(δ 1,κ , δ 2,κ )) where κ = 1,2,3,4 and Poth H(h 0 ,g 0 ) and H(δ 1,κ ,δ 2,κ ) are frequency independent Hurwitz-like matrices.
Control and Automation, 2003. ICCA '03. Proceedings. 4th International Conference on; 07/2003
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ABSTRACT: This paper considers the stability analysis problem of nD discrete-time systems. It is shown that the problems of stability test and stability margin computation for an nD system described by Roesser model can be recast into μ analysis problems in a unified way, thus can be solved effectively by using the commercially available software package.
Control and Automation, 2003. ICCA '03. Proceedings. 4th International Conference on; 07/2003
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ABSTRACT: The operating characteristics of parametric transformers and dc-ac converters with an orthogonal core depend heavily on the core shape. Accordingly, to obtain the optimal design for such devices, the quantitative relationship between the orthogonal core shape and the operating characteristics of the application device are determined. In this paper, the application characteristics are discussed analytically in terms of the orthogonal core shape, with reference to a magnetic circuit model of the core.
IEEE Translation Journal on Magnetics in Japan 02/1994;
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ABSTRACT: The running characteristics of the split-phase capacitor motor in
which a triac is connected in series with the motor circuit to control
the applied voltage in accordance with the load conditions are studied.
Ferrite magnetic wedges are inserted into the slot openings on the motor
stator. The wedging effect on the motor characteristics is studied. When
the ferrite wedges are inserted into the slot openings, the flux density
pulsation in the air gap is decreased greatly to decrease the inner
power losses, resulting in the improvement of motor efficiency and
characteristics
IEEE Transactions on Magnetics 12/1993; · 1.36 Impact Factor
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ABSTRACT: One method for calculating flux-MMF relationship of an orthogonal
core is described. The calculation is based on a three-dimensional
magnetic circuit model of the orthogonal core. The model is derived by
dividing the orthogonal core, inclusive of the surrounding region, into
elements comprising a three-dimensional magnetic circuit. Using this
model, the flux-MMF relationship of the orthogonal core with arbitrary
dimensions can be calculated from the B-H characteristic of the core
material. The calculation method presented is useful for optimum design
of devices using an orthogonal core
IEEE Transactions on Magnetics 12/1993; · 1.36 Impact Factor
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ABSTRACT: Orthogonal-cores have various potential applications, for instance in parametric transformers and dc-ac converters. The operating characteristics of the devices can be calculated on the basis of the measured relationship of flux to MMF of the orthogonal -core. To achieve optimal design of the applied device, the relationship of flux to MMF must be determined; however, this involves solving a three dimensional nonlinear problem. In this paper, we calculate the flux-MMF relationship based on a magnetic circuit model for the orthogonal-core. The computed results agree well with experiment. The method of this study is shown to be valid for calculation of characteristics and useful for optimal design of application devices.
IEEE Translation Journal on Magnetics in Japan 04/1993;
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ABSTRACT: The flux density distribution in the air gap on revolving electric
machines is distorted by the presence of slots and teeth to produce
rotor pole face eddy current and stator tooth pulsation losses,
resulting in the reduction of motor efficiency. When the asymmetric
voltage controlled by switching devices such as a triac is applied to
the motor, the voltage and current also pulsate to increase power
losses. In the present study, ferrite magnetic wedges have been inserted
into the stator slot openings of the capacitor motor and some
experiments under the triac control have been carried out. It is found
that the pulsation of the flux density distribution in the air gap is
decreased by wedging the ferrite materials to increase the apparent
magnetic permeability. This resulted in decreasing the motor power
losses and improving the motor running characteristics
IEEE Transactions on Magnetics 10/1992; · 1.36 Impact Factor
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ABSTRACT: This paper describes an analysis of the behavior of orthogonal-core type push-pull parametric transformers, taking the iron loss of the orthogonal-cores and the copper loss of the windings into consideration. The analysis was performed for the magnetic circuit of the orthogonal-core under magnetic saturation and with hysteresis. To improve the accuracy of calculations, the saturation characteristic was approximated by a series which includes terms of up to 21st order in the flux, and the hysteresis curve by a series including terms of up to 5th order in the exciting voltage. The calculated results show good agreement with experimental data. The analytical method presented here is useful for optimizing the design of push-pull parametric transformers.
IEEE Translation Journal on Magnetics in Japan 05/1992;
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ABSTRACT: With the development of condenser materials, single-phase capacitor motors for domestic use have been made smaller, and the utility for it has been raised in these days. For saving electric energy consumed in motors, the authors have carried out experimental discussions on the capacitor motor. In short, with wedging of soft ferrite materials into the motor slots, the characteristics in locked, no-loaded and loaded motor have been investigated. Owing to ferrite magnetic wedges, Carter's coefficient estimated by the finite element method was reduced, and iron loss of the motor decreased. As the result, efficiency of the motor was improved about 6 % or above.
IEEE Transactions on Magnetics 10/1986; · 1.36 Impact Factor
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ABSTRACT: It is well known that the harmonic torques in squirrel cage induction motors are caused by the space harmonic waves in air-gap flux distribution. The soft ferrite magnetic wedges inserted into the stator slot openings reduce the ripple of air-gap permeance. Therefore, this wedges reduce the magnitude of harmonic torques. A trial was performed on prevention of harmonic torques in squirrel cage induction motors, by inserting a soft ferrite magnetic wedges into its stator slot openings. Results obtained were as follows; (1) The soft ferrite magnetic wedges made it possible to decrease by about 40% the 17th and 19th asynchronous torques. (2) The magnitude of 17th and 19th asynchronous torque on the induction motor with the soft ferrite magnetic wedges and the unskewed rotor is approximately equivalent to that on the induction motor with the rotor skewed through 0.4 stator slot pitch. (3) The soft ferrite magnetic wedges were incapable of decreasing the 5th asynchronous and synchronous torque. The authors suggest that the utilization of soft ferrite magnetic wedges will become important to prevent the harmonic torques in induction motors.
IEEE Transactions on Magnetics 12/1982; · 1.36 Impact Factor
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ABSTRACT: To save electric power to be consumed in small induction motors, its efficiency improvement is required. As one of methods to improve the efficiency of small induction motors, magnetic materials have been wedged into the stator slots of the induction motors. Experiments have been performed on fabricated induction motors with soft ferrite wedged into stator slots. As the results, the decreasing of starting torques for the induction motors was found to be only 3 %. The efficiency of the ferrite wedged induction motors was improved by about 4 % at the rated output and 11 % at a quarter output, as compared with that without the soft ferrite.
IEEE Transactions on Magnetics 12/1982; · 1.36 Impact Factor
