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Finite Elements in Electromagnetics 2. Static fields. Oszkár Bíró IGTE, TU Graz Kopernikusgasse 24Graz, Austria email: biro@igte.tu-graz.ac.at. Overview. Maxwell‘s equations for static fields Static current field Electrostatic field Magnetostatic field.
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Finite Elements in Electromagnetics2. Static fields Oszkár Bíró IGTE, TU Graz Kopernikusgasse 24Graz, Austria email: biro@igte.tu-graz.ac.at
Overview • Maxwell‘s equations for static fields • Static current field • Electrostatic field • Magnetostatic field
on n+1 electrodes GE =GE0+GE1+GE2+ ...+ GEi+ ...+ GEn on the interface GJto the nonconducting region Static current field (1) n voltages between the electrodes are given: or or n currents through the electrodes are given: i = 1, 2, ..., n
Static current field (2) Symmetry GE0 may be a symmetry plane A part of GJ may be a symmetry plane
Static current field (3) Interface conditions Tangential E is continuous Normal J is continuous
Static current field (4) Network parameters (n>0) n=1: U1 is prescribed and or I1 is prescribed and n>1: or i = 1, 2, ..., n i = 1, 2, ..., n
Static current field (5) Scalar potential V
Static current field (6) Boundary value problem for the scalar potential V
Static current field (7) Operator for the scalar potential V
Static current field (8) Finite element Galerkin equations for V i = 1, 2, ..., n
Static current field (9) Current vector potential T
Static current field (10) Boundary value problem for the vector potential T
Static current field (11) Operator for the vector potential T
Static current field (12) Finite element Galerkin equations forT i = 1, 2, ..., n
Electrostatic field (1) n voltages between the electrodes are given: or n charges on the electrodes are given: i = 1, 2, ..., n on n+1 electrodes GE =GE0+GE1+GE2+ ...+ GEi+ ...+ GEn on the boundary GD
Electrostatic field (2) Symmetry GE0 may be a symmetry plane A part of GD (s=0) may be a symmetry plane
Electrostatic field (3) Interface conditions Tangential E is continuous Special case s=0: Normal D is continuous
Electrostatic field (4) Network parameters (n>0) n=1: U1 is prescribed and or Q1 is prescribed and n>1: or i = 1, 2, ..., n i = 1, 2, ..., n
Electrostatic field (5) Scalar potential V
Electrostatic field (6) Boundary value problem for the scalar potential V
Electrostatic field (7) Operator for the scalar potential V
Electrostatic field (8) Finite element Galerkin equations for V i = 1, 2, ..., n
Magnetostatic field (1) n magnetic voltages between magnetic walls are given: or or n fluxes through the magnetic walls are given: i = 1, 2, ..., n on n+1 magn. walls GE =GE0+GE1+GE2+ ...+ GEi+ ...+ GEn on the boundary GB
Magnetostatic field (2) Symmetry GH0 (K=0) may be a symmetry plane A part of GB (b=0) may be a symmetry plane
Magnetostatic field (3) Interface conditions Special case K=0: Tangential H is continuous Normal B is continuous
Magnetostatic field (4) Network parameters (n>0), J=0 n=1: Um1 is prescribed and or Y1 is prescribed and n>1: or i = 1, 2, ..., n i = 1, 2, ..., n
Magnetostatic field (5) Network parameter (n=0), b=0, K=0, J0 Inductance:
Magnetostatic field (6) Scalar potential F, differential equation
Magnetostatic field (7) Scalar potential F, boundary conditions
Magnetostatic field (8) Boundary value problem for the scalar potential F Full analogy with the electrostatic field
Magnetostatic field (9) Finite element Galerkin equations for F i = 1, 2, ..., n
Magnetostatic field (10) In order to avoid cancellation errors in computing T0 should be represented by means of edge elements: since and hence T0 and gradF(n) are in the same function space
Magnetostatic field (11) Magnetic vector potential A
Magnetostatic field (12) Boundary value problem for the vector potential A
Magnetostatic current field (13) Operator for the vector potential A
Magnetostatic field (14) Finite element Galerkin equations for A i = 1, 2, ..., n
Introduce T0 as Magnetostatic field (15) Consistence of the right hand side of the Galerkin equations