다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Journal of Non-Newtonian Fluid Mechanics

In this paper, a model-reference-based online identification method is proposed to estimate permanent-magnet synchronous machine (PMSM) parameters during transients and in steady state. It is shown that all parameters are not identifiable in steady state and a selection has to be made according to the user's objectives. Then, large signal convergence of the estimated parameters is analyzed using the second method of Lyapunov and the singular perturbations theory. It is illustrated that this method may be applied with a decoupling control technique that improves convergence dynamics and overall system stability. This method is compared with an extended Kalman filter (EKF)-based online identification approach, and it is shown that, in spite of its implementation complexity with respect to the proposed method, EKF does not give better results than the proposed method. It is also shown that the use of a simple PMSM model makes estimated parameters sensitive to those supposed to be known whatever the estimator is (both the proposed method and EKF). The simulation results as well as the experimental ones, implemented on a nonsalient pole PMSM, illustrate the validity of the analytic approach and confirm the same conclusions.

Online Identification of PMSM Parameters: Parameter Identifiability and Estimator Comparative Study

Review for order reduction based on proper orthogonal decomposition and outlooks of applications in mechanical systems

This paper presents the potential application of soft magnetic composite (SMC) material in low speed, directly driven, axial-flux permanent magnet (PM) wind generators. Comparative design studies are conducted on PM wind generators of different configurations with both lamination cores and SMC core. Finite element analysis is used to enhance the design precision, from which analytical formulas are modified. Through careful design an axial-flux PM wind generator with slotted SMC core is built and tested, demonstrating the advantages of better performance, reduced size and weight, low part count and low cost.

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Axial-flux PM wind generator with a soft magnetic composite core

In the domain of numerical computation, model order reduction approaches are more and more frequently applied in mechanics and have shown their efficiency in terms of reduction of computation time and memory storage requirements. One of these approaches, the proper orthogonal decomposition (POD), can be very efficient in solving linear problems but encounters limitations in the non-linear (NL) case. In this paper, the discrete empirical interpolation method coupled with the POD method is presented. This is an interesting alternative to reduce large-scale systems deriving from the discretization of NL magnetostatic problems coupled with an external electrical circuit.

/pdf/model-order-reduction-of-non-linear-magnetostatic-problems-579prmhrsy.pdf

Model Order Reduction of Non-Linear Magnetostatic Problems Based on POD and DEI Methods

A method for coupling magnetostatic and magnetodynamic finite element formulations with lumped reluctances is developed. Two dual h and b-conform formulations are extended to define the necessary magnetic relations between the magnetic fluxes and the magnetomotive forces. Adequate surface scalar potentials are defined and adequate boundary terms in the weak formulations are used. The magnetic relations can then be included in a reluctance network, in which the coupling of finite element regions and lumped regions aims at higher computational efficiency. The methods are developed in three dimensions, using a coupling of nodal and edge finite element approximations for the unknowns, and can easily be particularized in two dimensions.

Dual finite element formulations for lumped reluctances coupling

The proper orthogonal decomposition combined with the discrete empirical interpolation method is investigated in order to reduce a finite-element model of a multiple-input non-linear device. The non-linear reduced problem is solved using the Newton–Raphson method. The transient state of a three-phase transformer with a variable load is studied with the proposed reduction method for different supply voltage conditions.

/pdf/model-order-reduction-of-multiple-input-non-linear-systems-3fpufe1457.pdf

Model-Order Reduction of Multiple-Input Non-Linear Systems Based on POD and DEI Methods

In order to reduce the computation time and the memory resources required to solve an electromagnetic field problem, model order reduction approaches can be applied to reduce the size of the linear equation system obtained after discretisation. In the literature, the POD is widely used in engineering. In this paper, we propose to apply the POD in the case of a finite element problem accounting for the movement. The efficiency of this method is evaluated by considering an electrical motor and by comparing with the full model in terms of computational time and accuracy. Copyright © 2014 John Wiley & Sons, Ltd.

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Model order reduction applied to the numerical study of electrical motor based on POD method taking into account rotation movement

In order to reduce the computation time of a quasi-static problem solved by the finite element method, methods of model order reduction can be applied In this context, two approaches, the proper orthogonal decomposition and the proper generalized decomposition, are applied to the vector poten-tial formulation used to solve the quasi-static problem The developed methods are compared on an academic example

/pdf/model-order-reduction-of-quasi-static-problems-based-on-pod-3hvyomxjj9.pdf

Thomas Henneron

Papers

Model Order Reduction of Non-Linear Magnetostatic Problems Based on POD and DEI Methods

Dual finite element formulations for lumped reluctances coupling

Model-Order Reduction of Multiple-Input Non-Linear Systems Based on POD and DEI Methods

Model order reduction applied to the numerical study of electrical motor based on POD method taking into account rotation movement

Model order reduction of quasi-static problems based on POD and PGD approaches