• Journal of the Korean Mathematical Society
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• v.34 no.4
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• pp.825-839
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• 1997

The permanent function on certain faces of the polytope of doubly stochastic matrices are studied. These faces are shown to be barycentric, and the minimum values of permanent are determined.

• Honam Mathematical Journal
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• v.35 no.2
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• pp.211-223
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• 2013

We consider permanent function on the faces of the polytope of certain doubly stochastic matrices, whose nonzero entries coincide with those of fully indecomposable square (0, 1)-matrices containing identity submatrix. We determine the minimum permanents and minimizing matrices on the given faces of the polytope using the contraction method.

• The Pure and Applied Mathematics
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• v.14 no.3
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• pp.197-201
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• 2007

In this paper, when n = 6, we will determine the minimum permanent and minimizing matrices on the face of ${\Omega}_{n}$ which contains exactly two square zero-submatrices.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.4
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• pp.146-150
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• 2001

Comparison on the performances between the Halbach array type permanent magnet linear synchronous motor (HA-PMLSM) and the convensional array type permanent magnet linear synchronous motor (CA-PMLSM) was made with finite element analysis (FEA) and experiment. The HA-PMLSM is seen to be superior to the CA-PMLSM. Optimum ratio of magnet length to slot pitch of the HA-PMLSM which reduces the detent force was determined. Also, Comparison of forces of the HA-PMLSM and the CA-PMLSM with minimum detent force is presented.

• Journal of Power Electronics
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• v.14 no.1
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• pp.92-104
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• 2014

To insure stable operation and eliminate twice torque ripple, a topology for a six phase permanent magnet synchronous generator (SP-PMSG) with a neutral point connected together was analyzed in this paper. By adopting an extended transformation matrix, the mathematic model of the space vector control was established. The voltage and torque equations were deduced while considering the third harmonic flux and inductance. In addition, the suppression third harmonic method and the closed loop control strategy were proposed. A comparison analysis indicates that the cooper loss minimum method and the current magnitude minimum method can meet different application requirements. The voltage compensation amount for each of the methods was deduced which also takes into account the third harmonic effect. A simulation and experimental result comparison validates the consistency through theoretical derivation. It can be seen that all of the two control strategies can meet the requirements of post-fault.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2217-2220
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• 1997

To achieve the high performance speed control of synchronous permanent magnet motor, the influence of iron loss can not be negleced as the increase of driving frequency with high speed operation. This paper proposes a maximum efficiency control algorithm for permanent magnet synchonous motors by controlling the d-axis component of the armature current at any speed and torque. The objective of the optimum efficiency controller is to seek a combination of d-q axis current components which provide minimum input power (minimum losses) at a certain operating point by adding a small amout of perturbation to the d-axis current reference.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.272-283
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• 2017

In this paper, an improved predictive functional control (PFC) scheme for permanent magnet synchronous motor (PMSM) control system is proposed, on account of the standard PFC method cannot provides a satisfying disturbance rejection performance in the case of strong disturbances. The PFC-based method is first introduced in the control design of speed loop, since the good tracking and robustness properties of the PFC heavily depend on the accuracy of the internal model of the plant. However, in orthodox design of prediction model based control method, disturbances are not considered in the prediction model as well as the control design. A minimum-order observer (MOO) is introduced to estimate the disturbances, which structure is simple and can be realized at a low computational load. This paper adopted the MOO to observe the load torque, and the observations are then fed back into PFC model to rebuild it when considering the influence of perturbation. Therefore, an improved PFC strategy with torque compensation, called the PFC+MOO method, is presented. The validity of the proposed method was tested via simulation and experiments. Excellent results were obtained with respect to the speed trajectory tracking, stability, and disturbance rejection.

• Journal of the Korean Mathematical Society
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• v.32 no.2
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• pp.195-210
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• 1995

Let $\Omega_n$ denote the set of all $n \times n$ doubly stochatic matrices. Then it is well known that $\Omega_n$ forms convex polytope of dimension $(n-1)^2$ with n! extreme points in the $n^2$-dimensional Euclidean space.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1055-1056
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• 2011

This paper deals with optimum design criteria for maximum torque density & minimum current density of a single phase line-start permanent-magnet motor (LSPMM) using RSM (Response Surface Methodology) & FEM (Finite Element Method). The focus of this paper is to find a design solution through the comparison of torque density and minimum current density resulting from rotor shape variations. And then, a central composite design (CCD) mixed resolution is introduced, and analysis of variance (ANOVA) is conducted to determine the significance of the fitted regression model.

• Journal of the Korean Mathematical Society
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• v.36 no.5
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• pp.1009-1020
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• 1999

The minimum permanent and the set of minimizing matrices over the face of the polytope n of all doubly stochastic matrices of order n determined by any staircase matrix was determined in [4] in terms of some parameter called frame. A staircase matrix can be described very simply as a Ferrers matrix by its row sum vector. In this paper, some simple exposition of the permanent minimization problem over the faces determined by Ferrers matrices of the polytope of n are presented in terms of row sum vectors along with simple proofs.