98 lines
2.5 KiB
Mathematica
98 lines
2.5 KiB
Mathematica
|
%load all the FEMM functions. the folder with all the M files for FEMM should have already been added to path
|
|||
|
|
addpath('c:\\femm42\\mfiles');
|
|||
|
|
openfemm;
|
|||
|
|
|
|||
|
|
function make_round_turn(x, y, radius, material, circuit)
|
|||
|
|
x1 = x - radius;
|
|||
|
|
x2 = x + radius;
|
|||
|
|
y1 = y;
|
|||
|
|
y2 = y;
|
|||
|
|
|
|||
|
|
mi_drawarc(x1, y1, x2, y2, 180, 10);
|
|||
|
|
mi_addarc(x2, y2, x1, y1, 180, 10);
|
|||
|
|
|
|||
|
|
mi_addblocklabel(x,y);
|
|||
|
|
mi_selectlabel(x,y);
|
|||
|
|
%comment out first for automeshing
|
|||
|
|
mi_setblockprop(material, 1, 0, circuit, 0, 0, 1);
|
|||
|
|
%mi_setblockprop(material, 0, 10E-3, circuit, 0, 0, 1);
|
|||
|
|
mi_clearselected;
|
|||
|
|
|
|||
|
|
endfunction
|
|||
|
|
|
|||
|
|
% materials
|
|||
|
|
copper_conductivity = 58.0;
|
|||
|
|
|
|||
|
|
%parameters
|
|||
|
|
r_wire = 0.5; % radius of wire
|
|||
|
|
freq = 0;
|
|||
|
|
probe_offset = 0.1; % distance from probe tip to wire
|
|||
|
|
|
|||
|
|
%constants
|
|||
|
|
i_wire = 1;
|
|||
|
|
sensor_offset = 1.6; %offset of from sensor to end of probe tip
|
|||
|
|
probe_sensitivity_H = 0.8; %volts/gauss
|
|||
|
|
probe_sensitivity_L = 0.2;
|
|||
|
|
probe_max_G = 6.0; % max field strength for sensor saturation
|
|||
|
|
|
|||
|
|
|
|||
|
|
%create new document
|
|||
|
|
% "0 for a magnetics problem, 1 for an electrostatics problem, 2 for a heat flow problem, or 3 for a current flow problem"
|
|||
|
|
newdocument(0);
|
|||
|
|
|
|||
|
|
% Define the problem type. Magnetostatic; Units of mm; Axisymmetric;
|
|||
|
|
% Precision of 10^(-8) for the linear solver; a placeholder of 0 for
|
|||
|
|
% the depth dimension, and an angle constraint of 30 degrees
|
|||
|
|
|
|||
|
|
%(freq,units,type,precision,depth,minangle,(acsolver))
|
|||
|
|
mi_probdef(freq, 'millimeters', 'planar', 1.e-8, 100, 30);
|
|||
|
|
|
|||
|
|
%define materials and circuits
|
|||
|
|
|
|||
|
|
mi_addmaterial('Air', 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0);
|
|||
|
|
mi_addmaterial('Copper', 1, 1, 0, 0, copper_conductivity, 0, 0, 1, 0, 0, 0);
|
|||
|
|
|
|||
|
|
mi_addcircprop('iwire', i_wire, 1);
|
|||
|
|
|
|||
|
|
%air
|
|||
|
|
mi_addblocklabel(0, -5);
|
|||
|
|
mi_selectlabel(0,-5);
|
|||
|
|
% (’blockname’, automesh, meshsize, ’incircuit’, magdir, group, turns)
|
|||
|
|
mi_setblockprop('Air', 1, 0, '<None>', 0, 0, 0);
|
|||
|
|
mi_clearselected
|
|||
|
|
|
|||
|
|
% wire
|
|||
|
|
make_round_turn(0,0,r_wire,'Copper', 'iwire');
|
|||
|
|
|
|||
|
|
%boundary condition
|
|||
|
|
mi_makeABC(5, 25, 0,0, 0);
|
|||
|
|
mi_saveas('wire.fem');
|
|||
|
|
|
|||
|
|
% mesh
|
|||
|
|
smartmesh(1);
|
|||
|
|
mi_createmesh();
|
|||
|
|
|
|||
|
|
|
|||
|
|
%run simulation
|
|||
|
|
mi_analyze();
|
|||
|
|
mi_loadsolution();
|
|||
|
|
|
|||
|
|
%obtain B field
|
|||
|
|
|
|||
|
|
measuredB = abs(mo_getb(0,(r_wire + probe_offset + sensor_offset))(1));
|
|||
|
|
measuredG = measuredB ./ 1E-4; % convert tesla to gauss
|
|||
|
|
current_sensitivity_H = measuredG * probe_sensitivity_H;
|
|||
|
|
current_sensitivity_L = measuredG * probe_sensitivity_L;
|
|||
|
|
|
|||
|
|
probe_max_current = probe_max_G ./ measuredG;
|
|||
|
|
disp("Field Strength:");
|
|||
|
|
disp(measuredG);
|
|||
|
|
disp("Sensitivity High Gain:");
|
|||
|
|
disp(current_sensitivity_H);
|
|||
|
|
disp("Sensitivity Low Gain:");
|
|||
|
|
disp(current_sensitivity_L);
|
|||
|
|
disp("Max Current:");
|
|||
|
|
disp(probe_max_current);
|
|||
|
|
|
|||
|
|
|