Variational equality in electromagnetic engineering of ship electrical equipments

摘要

This paper is the achievement in the numerical analysis of the electromagnetic fields which is the fundamental theory and basic method in Electromagnetic Engineering of ship electrical equipments. The numerical analysis of the electromagnetic fields in ship electrical equipments aims at building up their normal distribution of the electromagnetic fields. It is of great importance to improving upon their designing functiong and operating. Electromagnetic Engineering of ship electrical equipments deals with a wide range of disciplines. We can graft the finite element method in mechanics into Electromagnetic Engineering. Then the nonlinear partial differential equation of the electromagnetic field is replaced by a variational Problem. The finite element method used here is based on variational method. Consists of finding a function that minimizes a certain specified energy functional over the entire region in the equipment so as to gear the variational equation (i.e. Euler equation) to that nonlinear partial differential equation. Normally, there is the magnetic saturation in the ferrous--core material of ship electrical equipments. Therefore this paper reports on the formulation of nonlinear energy functional of saturable magnetic field. and we shall prove the propositiion that the correct solution of nonllinear Poisson equation is always on an equality with minimizing the nonlinear energy functional in the saturable magnetic field.