Search

A general and precise method to model rotary machines based on transient magnetic field computation using finite-element method (FEM) is presented. The merits of the proposed method are that the nonlinear iteration on the rotor position can be avoided. Formulas to predict the rotor position and speed of the machine are deduced based on Taylor's expansion. A curvilinear element is used on the two sides of the sliding surface to reduce the numerical noises arising from mesh rotation. The proposed methods for dealing with matching boundary conditions and periodic boundary conditions are very general, accurate and flexible. Typical numerical experiment shows that the numerical error of the local magnetic potentials on the motion sliding surface is only one twentieth of that of traditional interpolation method. [ABSTRACT FROM PUBLISHER]

A general and simple method to couple arbitrarily connected circuits and multislice magnetic fields in the time stepping finite element analysis of electromechanical devices and electrical machines is presented in detail. The merits of the proposed method are that the sparsity of the finite element equations is improved, the formulations to be described wilt allow unequal division of the axial length of the motor in the multi-slice model, the stranded windings (with negligible eddy current) and solid conductors (with eddy current) in the field domain can be connected arbitrarily with the external circuits, and the coefficient matrix of the system is symmetrical and the nonlinear power electronic elements can be easily maneuvered in the formulations. As illustrating examples, the proposed approach is used to simulate the operations of a brushless d.c. motor and a hard disk drive spindle motor. [ABSTRACT FROM AUTHOR]