def add_pcbs(tg):
'''Add primary and secondary side pcbs.'''
# coordinates of the PCB on the primary side
if tg.layers_primary == 1 or tg.layers_primary == 2:
coords_pcb_prim = coords_of_rectangle(
0, tg.height_dielectric + tg.height_copper + tg.height_gap,
tg.radius_pcb, tg.height_pcb_core)
elif tg.layers_primary == 4:
coords_pcb_prim = coords_of_rectangle(
0, tg.height_dielectric + tg.height_copper + tg.height_gap,
tg.radius_pcb, tg.height_pcb_core + 2 * tg.height_pcb_prepreg +
2 * tg.height_copper)
else:
print('Unknown number of layers on primary side')
femm.closefemm()
return (0, 0)
# coordinates of the PCB on the secondary side
if tg.layers_secondary == 1 or tg.layers_secondary == 2:
coords_pcb_sec = coords_of_rectangle(0,
-tg.height_copper - tg.height_gap,
tg.radius_pcb,
-tg.height_pcb_core)
elif tg.layers_secondary == 4:
coords_pcb_sec = coords_of_rectangle(
0, -tg.height_copper - tg.height_gap, tg.radius_pcb,
-tg.height_pcb_core - 2 * tg.height_pcb_prepreg -
2 * tg.height_copper)
else:
print('Unknown number of layers on secondary side')
femm.closefemm()
return (0, 0)
femm.mi_drawrectangle(*coords_pcb_prim)
femm.mi_drawrectangle(*coords_pcb_sec)
def add_pcbs(tg, label_dict):
'''Add primary and secondary side pcbs.
Args:
tg (TransformerGeometry): contains all geometry information needed
to build conductors in the problem.
label_dict (dict): stores coordinates
'''
# coordinates of the PCB on the primary side
if tg.layers_primary == 1 or tg.layers_primary == 2:
coords_pcb_prim = coords_rectangle(
0, tg.height_dielectric + tg.height_copper + tg.height_gap,
tg.radius_pcb, tg.height_pcb_core)
elif tg.layers_primary == 4:
coords_pcb_prim = coords_rectangle(
0, tg.height_dielectric + tg.height_copper + tg.height_gap,
tg.radius_pcb, tg.height_pcb_core + 2 * tg.height_pcb_prepreg +
2 * tg.height_copper)
else:
print('Unknown number of layers on primary side')
femm.closefemm()
return (0, 0)
# coordinates of the PCB on the secondary side
if tg.layers_secondary == 1 or tg.layers_secondary == 2:
coords_pcb_sec = coords_rectangle(0, -tg.height_copper - tg.height_gap,
tg.radius_pcb, -tg.height_pcb_core)
elif tg.layers_secondary == 4:
coords_pcb_sec = coords_rectangle(
0, -tg.height_copper - tg.height_gap, tg.radius_pcb,
-tg.height_pcb_core - 2 * tg.height_pcb_prepreg -
2 * tg.height_copper)
else:
print('Unknown number of layers on secondary side')
femm.closefemm()
return (0)
femm.ei_drawrectangle(*coords_pcb_prim)
femm.ei_drawrectangle(*coords_pcb_sec)
label_dict['PCB_prim'] = coords_pcb_prim
label_dict['PCB_sec'] = coords_pcb_sec
def calc_inductance(tg, currents, inductances=(None, None), **kwargs):
''' Setup of magneto-static problem in femm to calculate inductance and
resistance of planar transformer.
Args:
tg (:obj:'TransformerGeometry'): tg contains all geometry information
of the transformer.
currents (list of float): currents in the primary and secondary side
circuits on the form [I_prim, I_sec].
inductances (list of float): self-inductances of the primary and
secondary side circuits on the form [L_prim, L_sec]. Used to calculate
mutual inductance.
Returns:
(inductance, resistance): calculated self or mutual inductance and
equivalent series resistance of either primary or secondary circuit.
'''
etiquettes_dict = {} # Dictionary to store coordinates of nodes
# initialitiation of the magneto-static problem
boundary_radius = 2 * tg.radius_dielectric
initial_setup(boundary_radius, currents, **kwargs)
# draw geometry and add block labels
add_conductors(tg, etiquettes_dict)
add_pcbs(tg)
add_isolation(tg)
add_block_labels(tg, etiquettes_dict)
# mi zoomnatural()
# From manual: zooms to a “natural” view with sensible extents.
femm.mi_zoomnatural()
# Saving geometry file
femm.mi_saveas('inductance_transformer.fem')
# Meshing and analysis
# From manual: Note that it is not necessary to run mesh before performing
# an analysis, as mi_analyze() will make sure the mesh is up to date before
# running an analysis.
# mi analyze(flag)
# From manual: runs fkern to solve the problem. The flag parameter controls
# whether the fkern window is visible or minimized. For a visible window,
# either specify no value for flag or specify 0. For a minimized window,
# flag should be set to 1.
femm.mi_analyze(1)
# Post-processing
femm.mi_loadsolution()
# mo_seteditmode(mode)
# From manual: Sets themode of the postprocessor to point, contour, or area
# mode. Valid entries for mode are "point", "contour", and "area".
femm.mo_seteditmode('area')
# mo_blockintegral(type)
# From manual: Calculate a block integral for the selected blocks
# Type Definition
# 0 A · J
# 1 A
# 2 Magnetic field energy
# 3 Hysteresis and/or lamination losses
# 4 Resistive losses
# 5 Block cross-section area
# 6 Total losses
# 7 Total current
# 8 Integral of Bx (or Br) over block
# 9 Integral of By (or rBz) over block
# 10 Block volume
# ...
# mo_getcircuitproperties("circuit")
# From manual: Used primarily to obtain impedance information associated
# with circuit properties. Properties are returned for the circuit property
# named "circuit". Three values are returned by the function. In order,
# these results are:
# – current Current carried by the circuit
# – volts Voltage drop across the circuit
# – flux_re Circuit’s flux linkage
# mo_groupselectblock(n)
# From manual: Selects all the blocks that are labeled by block labels
# that are members of group n. If no number is specified (i.e.
# mo_groupselectblock() ), all blocks are selected.
# Calculate the inductance of the circuit with non-zero current. If both
# currents are given, we calculate the mutual inductance.
L1, L2 = inductances
if (currents[0] > 0) and (currents[1] == 0):
circ = femm.mo_getcircuitproperties('phase_prim')
resistance = circ[1].real
inductance = abs(circ[2] / circ[0])
elif (currents[0] == 0) and (currents[1] > 0):
circ = femm.mo_getcircuitproperties('phase_sec')
resistance = circ[1].real
inductance = abs(circ[2] / circ[0])
else:
femm.mo_groupselectblock()
# axisymmetric problem, integral is multiplied by 2
Wm = femm.mo_blockintegral(2) * 2
inductance = ((Wm - 0.5 *
(L1 * currents[1]**2 + L2 * currents[0]**2)) /
(currents[0] * currents[1]))
resistance = 0
femm.mo_clearblock()
if kwargs.get('close') is True:
femm.closefemm()
return (inductance, resistance)
femm.ei_zoomnatural()
# Save the geometry to disk so we can analyze it
femm.ei_saveas('strips.fee')
# Create a placeholder matrix which we will fill with capacitance values
c = []
for k in range(0, 4):
femm.ei_modifyconductorprop('v0', 1, 1 if (k == 0) else 0)
femm.ei_modifyconductorprop('v1', 1, 1 if (k == 1) else 0)
femm.ei_modifyconductorprop('v2', 1, 1 if (k == 2) else 0)
femm.ei_modifyconductorprop('v3', 1, 1 if (k == 3) else 0)
femm.ei_analyze()
femm.ei_loadsolution()
c.append([
femm.eo_getconductorproperties('v0')[1],
femm.eo_getconductorproperties('v1')[1],
femm.eo_getconductorproperties('v2')[1],
femm.eo_getconductorproperties('v3')[1]
])
femm.closefemm()
print('The capacitance matrix (pF/m):')
for j in range(0, 4):
for k in range(0, 4):
c[j][k] *= 10**12
print(c[j])
def calc_field_distribution(tg, voltage_high=1, view=None, **kwargs):
''' Setup of electro-static problem in femm to calculate capacitance
between primary and secondary side of planar transformer. Additionally,
electric field can be investigated
Args:
tg (:obj:'TransformerGeometry'): tg contains all geometry information
needed to solve the problem.
voltage_high (float): Voltage potential of the primary side.
view (:obj:'View'): Save images of edges and guards.
Returns:
capacitance (float): calculated capacitance between primary and
secondary side of planar transformer.
'''
etiquettes_dict = {} # Dictionary to store coordinates of nodes
# initialitiation of the electro-static problem
boundary_radius = 2 * tg.radius_dielectric
initial_setup(boundary_radius, voltage_high, **kwargs)
# draw conductors on primary and secondary sides
add_conductors(tg, etiquettes_dict)
add_pcbs(tg, etiquettes_dict)
add_isolation(tg)
add_block_labels(tg, etiquettes_dict)
round_conductor_edges(tg, etiquettes_dict, kwargs.get('segment_angle'))
# if tg.edge_type == 'Round':
# round_conductor_edges(tg, etiquettes_dict)
# elif tg.edge_type == 'Trapezoidal':
# trapezoidal_conductor_edges(tg, etiquettes_dict)
if tg.tracks:
modify_tracks(tg, etiquettes_dict, kwargs.get('segment_angle'))
if tg.guard:
add_guard(tg, tg.guard, etiquettes_dict)
# mi zoomnatural()
# From manual: zooms to a “natural” view with sensible extents.
femm.ei_zoomnatural()
# Save geometry file
femm.ei_saveas('field_calculations.fee')
# Meshing and analysis
# From manual: Note that it is not necessary to run mesh before performing
# an analysis, as mi_analyze() will make sure the mesh is up to date before
# running an analysis.
# mi analyze(flag)
# From manual: runs fkern to solve the problem. The flag parameter controls
# whether the fkern window is visible or minimized. For a visible window,
# either specify no value for flag or specify 0. For a minimized window,
# flag should be set to 1.
femm.ei_analyze(1)
# Post-processor
femm.ei_loadsolution()
# eo_showdensityplot(legend,gscale,type,upper D,lower D)
# From manual: Shows the flux density plot with options:
# legend Set to 0 to hide the plot legend or 1 to show the plot legend.
# gscale Set to 0 for a colour density plot or 1 for a grey scale density
# plot.
# type Sets the type of density plot. A value of 0 plots voltage, 1 plots
# the magnitude of D, and 2 plots the magnitude of E
# upper D Sets the upper display limit for the density plot.
# lower D Sets the lower display limit for the density plot.
if 'plot_field_max' in kwargs:
femm.eo_showdensityplot(1, 0, 2, kwargs['plot_field_max'] * 20 / 19, 0)
# Save field lines along outer point of the PCB conductors. If the
# conductors have trapezoidal shape, it is difficult to estimate where the
# peak field will be. Hence, the contour lines are not saved.
# if not edge_trapezoid:
# save_field_contour(ep_cuivre, etiquettes_dict, guard=guard)
if view:
set_view(view, tg.guard, etiquettes_dict)
# eo_getconductorproperties("conductor")
# From manual: Properties are returned for the conductor property named
# ”conductor”. Two values are returned: The voltage of the specified
# conductor, and the charge carried on the specified conductor.
# Calculate the capacitance
circuit_properties = femm.eo_getconductorproperties('zero')
charge = -circuit_properties[1] # get charge on secondary side conductors
capacitance = charge / voltage_high
if kwargs.get('close') is True:
femm.closefemm()
return capacitance
femm.mi_clearselected()
femm.mi_zoomnatural() # to check geometry while debuging
femm.mi_saveas('ring.fem')
# meshing
# automaticaly done by the analysis function
# analysis
femm.mi_analyze()
# result data export
femm.mi_loadsolution()
# plot the flux density along z axis
zee = []
bee = []
for n in range(-0, 30):
b = femm.mo_getb(0, n)
zee.append(n)
bee.append(b[1])
plt.plot(zee, bee)
plt.ylabel('Flux Density, Tesla')
plt.xlabel('Distance along the z-axis, mm')
plt.title('Plot of flux density along the axis')
plt.grid()
plt.show()
femm.closefemm() # close the instance of femm
def closeSimulation(self):
femm.closefemm()
def closeFemm(filename='test.fem'):
femm.mi_saveas(filename)
femm.closefemm()
def fermeture_simulation(self):
"""Fermeture de FEMM"""
femm.closefemm()