def increase_pcb_mesh(cut_in, dz, segment_length, label_dict):
'''Decrease segment size to increase mesh along edge of PCB where the
field is high.
Args:
cut_in (float): how far along the pcb edge from the conductor where the
segment length is decreased
dz (float): copper height of conductors
segment_length (float): specifiy segment length in femm
label_dict (dict): stores label coordinates
'''
pcb_segment = []
pcb_node = []
pcb_node.append((np.array(label_dict['edge0']) + np.array(
(-cut_in * 1.5, dz / 2.))))
pcb_segment.append(pcb_node[-1] + np.array((cut_in / 2., 0)))
pcb_node.append((np.array(label_dict['edge1']) + np.array(
(cut_in * 1.5, dz / 2.))))
pcb_segment.append(pcb_node[-1] + np.array((-cut_in / 2., 0)))
pcb_node.append((np.array(label_dict['edge2']) + np.array(
(-cut_in * 1.5, -dz / 2.))))
pcb_segment.append(pcb_node[-1] + np.array((cut_in / 2., 0)))
pcb_node.append((np.array(label_dict['edge3']) + np.array(
(cut_in * 1.5, -dz / 2.))))
pcb_segment.append(pcb_node[-1] + np.array((-cut_in / 2., 0)))
for idx, node in enumerate(pcb_node):
femm.ei_addnode(*node)
label_dict['edge' + str(idx) + 'pcb'] = node
for segment in pcb_segment:
femm.ei_selectsegment(*segment)
femm.ei_setsegmentprop('<None>', segment_length, 0, 0, 0, '<None>')
femm.ei_clearselected()
def set_conductor_boundry(coords, in_conductor):
'''Set voltage potential of the four sides of a square conductor.'''
femm.ei_selectsegment(coords[0], np.average((coords[1], coords[3])))
femm.ei_selectsegment(np.average((coords[0], coords[2])), coords[1])
femm.ei_selectsegment(coords[2], np.average((coords[1], coords[3])))
femm.ei_selectsegment(np.average((coords[0], coords[2])), coords[3])
if in_conductor == 1:
femm.ei_setsegmentprop('<None>', 0, 1, 0, 0, 'high')
elif in_conductor == 0:
femm.ei_setsegmentprop('<None>', 0, 1, 0, 0, 'zero')
femm.ei_clearselected()
def __init__(self, origin_x, origin_y, width, height):
assert isinstance(self.problemType,
ProblemType), f"No problem type specified"
self.index = Rectangle.next_index
Rectangle.next_index += 1
self.origin_x = origin_x
self.origin_y = origin_y
self.width = width
self.height = height
self.prefix = Prefixes[self.problemType]
self.draw()
self.select_periphery()
if self.problemType is ProblemType.ElectroStatic:
femm.ei_setsegmentprop('<None>', 0, 1, 0, self.index, '<None>')
elif self.problemType is ProblemType.MagnetoStatic:
femm.mi_setsegmentprop('<None>', 0, 1, 0, self.index)
else:
assert False
self.clearselected()
# Create and assign a "periodic" boundary condition to
# model an unbounded problem via the Kelvin Transformation
femm.ei_addboundprop('periodic', 0, 0, 0, 0, 3)
femm.ei_selectarcsegment(0, 100)
femm.ei_selectarcsegment(110, 80)
femm.ei_setarcsegmentprop(2.5, 'periodic', 0, 0, '<none>')
femm.ei_clearselected()
# Define the ground plane in both the geometry and the exterior region
femm.ei_addboundprop('ground', 0, 0, 0, 0, 0)
femm.ei_selectsegment(0, -20)
femm.ei_selectsegment(110, -20)
femm.ei_selectsegment(-110, -20)
femm.ei_selectsegment(110, 100)
femm.ei_setsegmentprop('ground', 0, 1, 0, 0, '<none>')
femm.ei_clearselected()
# Add block labels for each strip and mark them with "No Mesh"
for k in range(0, 4):
femm.ei_addblocklabel(-36 + k * 24, 1)
for k in range(0, 4):
femm.ei_selectlabel(-36 + k * 24, 1)
femm.ei_setblockprop('<No Mesh>', 0, 1, 0)
femm.ei_clearselected()
# Add and assign the block labels for the air and dielectric regions
femm.ei_addmaterial('air', 1, 1, 0)
femm.ei_addmaterial('dielectric', 4, 4, 0)
femm.ei_addblocklabel(0, -10)
femm.ei_addblocklabel(0, 50)
def analyseCapacitor(flexPercent):
# Create a new electrostatics problem
femm.newdocument(1)
# Draw the geometry
femm.ei_probdef('centimeters', 'axi', 10**(-8), 30)
femm.ei_drawrectangle(0, -SPACE, RADIUS,
-DISTANCE) # bottom plate and dielectric
# femm.ei_drawline(0,0,RADIUS,0) # top plate
for i in range(0, NODECOUNT):
femm.ei_drawline(i * dr, getPlateZ(flexPercent, i * dr), (i + 1) * dr,
getPlateZ(flexPercent, (i + 1) * dr))
femm.ei_drawarc(0, -RADIUS * 5, 0, RADIUS * 5, 180, 2.5) # arc boundary
femm.ei_drawline(0, -RADIUS * 5, 0, RADIUS * 5) # line boundary
# Create and assign a "fixed voltage" boundary condition to curve
femm.ei_addboundprop('Fixed Voltage', 0.5, 0, 0, 0, 0)
femm.ei_selectarcsegment(0, -RADIUS * 5)
femm.ei_setarcsegmentprop(2.5, 'Fixed Voltage', 0, 0, '<none>')
femm.ei_clearselected()
# Add and assign the block labels for the air and dielectric regions
femm.ei_addmaterial('air', 1, 1, 0)
femm.ei_addmaterial('dielectric', 3, 3, 0)
femm.ei_addblocklabel(10, 10)
femm.ei_selectlabel(10, 10)
femm.ei_setblockprop('air', 0, 1, 0)
femm.ei_clearselected()
femm.ei_addblocklabel(RADIUS / 2, -DISTANCE + DI_WIDTH / 2)
femm.ei_selectlabel(RADIUS / 2, -DISTANCE + DI_WIDTH / 2)
femm.ei_setblockprop('dielectric', 0, 1, 0)
femm.ei_clearselected()
# Add a "Conductor Property" for each of the plates
femm.ei_addconductorprop('anode', 1, 0, 1)
femm.ei_addconductorprop('cathode', 0, 0, 1)
# Assign the anode properties to all sides of the first strip
# femm.ei_selectsegment(RADIUS/2,0)
for i in range(0, NODECOUNT):
femm.ei_selectsegment((i + 0.5) * dr,
getPlateZ(flexPercent, (i + 0.5) * dr))
femm.ei_setsegmentprop('<None>', 0.25, 0, 0, 0, 'anode')
femm.ei_clearselected()
# Assign the cathode properties to all sides of the fourth strip
femm.ei_selectsegment(RADIUS / 2, -DISTANCE)
femm.ei_setsegmentprop('<None>', 0.25, 0, 0, 0, 'cathode')
femm.ei_clearselected()
femm.ei_zoomnatural()
# Save the geometry to disk so we can analyze it
femm.ei_saveas('capacitors/capacitorflex' + str(flexPercent) + '.fee')
femm.ei_analyze()
femm.ei_loadsolution()
femm.eo_selectblock(10, 10)
energy = femm.eo_blockintegral(0)[0]
return energy
def draw_guard_trench(tg, trench, label_name, label_dict):
'''Draw a trench on the outside of turn closest to the dielectric.
Args:
tg (:obj:'TransformerGeometry'): contains all geometry information
trench (:obj:'GuardTrench'): trench guard geometry
label_name (str): label that identifies the guard in the dict
label_dict (dict): stores label coordinates
'''
conductor_height = tg.height_copper
conductor_width = tg.width_copper
max_angle = 2
elementsize = 0.05
if trench.inner:
sign = -1
turns = 1
else:
sign = 1
turns = tg.turns_primary
# find starting point
if trench.polarity:
node0 = (np.array(label_dict['prim' + str(turns - 1)]) + np.array(
(conductor_width[0] * sign, conductor_height)) / 2.0 + np.array(
(trench.distance * sign, 0)))
in_conductor = 'high'
pm = 1 # polarity multiplier
else:
node0 = (np.array(label_dict['sec' + str(turns - 1)]) + np.array(
(conductor_width[1] * sign, -conductor_height)) / 2.0 + np.array(
(trench.distance * sign, 0)))
in_conductor = 'zero'
pm = -1 # polarity multiplier
# draw four/five points and lines between points 1 to last to 0
nodes = [(0, 0), (trench.width * sign, 0),
(trench.width * sign, trench.depth * pm), (0, trench.depth * pm)]
if trench.drill_angle > 90:
alpha = (1.0 - trench.drill_angle / 180.) * pi
depth_added = trench.width / (2.0 * np.tan(alpha))
nodes.insert(-1, (trench.width / 2.0 * sign,
(trench.depth + depth_added) * pm))
nodes = [node0 + np.array(n) for n in nodes]
for idx, n in enumerate(nodes):
femm.ei_addnode(*n)
label_dict[label_name + 'node' + str(idx)] = n
ind = range(1, len(nodes)) + [
0,
]
segment_gen = (np.concatenate((nodes[ind[idx]], nodes[ind[idx + 1]]))
for idx in range(len(nodes) - 1))
for n in segment_gen:
femm.ei_addsegment(*n)
femm.ei_selectsegment(*(np.mean((n[:2], n[2:]), axis=0)))
femm.ei_setsegmentprop('None', elementsize, 0, 0, 'None', in_conductor)
femm.ei_clearselected()
# remove existing segment of the PCB
femm.ei_selectsegment(*(np.mean((nodes[0:2]), axis=0)))
femm.ei_deleteselectedsegments()
# draw circular top
if (pm == 1 and sign == 1) or (pm == -1 and sign == -1):
femm.ei_addarc(nodes[0][0], nodes[0][1], nodes[1][0], nodes[1][1],
trench.outer_angle, max_angle)
else:
femm.ei_addarc(nodes[1][0], nodes[1][1], nodes[0][0], nodes[0][1],
trench.outer_angle, max_angle)
# set conductor properties on the boundries
femm.ei_selectarcsegment(*(np.mean((nodes[0:2]), axis=0)))
femm.ei_setarcsegmentprop(max_angle, 'None', 0, 'None', in_conductor)
# add label and set material
label_dict[label_name] = (nodes[0] + np.array(
(trench.width / 2. * sign, trench.depth * pm / 2.)))
femm.ei_addblocklabel(*label_dict[label_name])
femm.ei_selectlabel(*label_dict[label_name])
femm.ei_setblockprop(trench.material, 1, 0, 'None')
femm.ei_clearselected()
def trapezoidal_conductor_edges(tg, label_dict):
'''Make the edges of conductors trapezoidal for those that are critical to
the peak field calculations. These conductors will be the ones closest to
the dielectric material, and both inner and outer conductor corners.
Args:
tg (:obj:'TransformerGeometry'): contains all geometry information
needed to build conductors in the problem.
label_dict (dict): stores label coordinates
'''
# Define parameters of the rounding
turns = tg.turns_primary
conductor_height = tg.height_copper
conductor_width = tg.width_copper
cut_in_length = 2 * conductor_height # percentage of conductor height
corner_radius = 1.7 * conductor_height
ledge_height = 0.005
ledge_radius = 0.004
segment_length = 0.004
angle_max = 1
# Make trapezaoidal corners on primary side corners and add new labels for
# the new points. Sequence: -> find corner to be moved -> set segment props
# -> make ledge -> move corner to make trapezoid -> add nodes for edge and
# edge corner -> repeat for all corners -> set all segment props -> round
# all edges -> set all arcsegment props -> set segment props along pcb for
# all trapezoidal conductor edges.
# Primary inner corner
inner_corner = (np.array(label_dict['prim0']) + np.array(
(-conductor_width / 2., -conductor_height / 2.)))
femm.ei_selectsegment(*(inner_corner +
np.array((0, conductor_height / 2.))))
femm.ei_setsegmentprop('<None>', segment_length, 0, 0, 0, 'high')
label_dict['ledge0corner'] = (inner_corner + np.array(
(0, conductor_height - ledge_height)))
femm.ei_addnode(*label_dict['ledge0corner'])
femm.ei_selectnode(*inner_corner)
femm.ei_movetranslate(cut_in_length, 0)
label_dict['edge0'] = (np.array(label_dict['prim0']) + np.array(
((-conductor_width + cut_in_length) / 2., 0)))
label_dict['edge0corner'] = inner_corner + np.array((cut_in_length, 0))
# Primary outer corner
outer_corner = (np.array(label_dict['prim' + str(turns - 1)]) + np.array(
(conductor_width / 2., -conductor_height / 2.)))
femm.ei_selectsegment(*(outer_corner +
np.array((0, conductor_height / 2.))))
femm.ei_setsegmentprop('<None>', segment_length, 0, 0, 0, 'high')
label_dict['ledge1corner'] = (outer_corner + np.array(
(0, conductor_height - ledge_height)))
femm.ei_addnode(*label_dict['ledge1corner'])
femm.ei_selectnode(*outer_corner)
femm.ei_movetranslate(-cut_in_length, 0)
label_dict['edge1'] = (np.array(label_dict['prim' + str(turns - 1)]) +
np.array(
((conductor_width - cut_in_length) / 2., 0)))
label_dict['edge1corner'] = outer_corner + np.array((-cut_in_length, 0))
# Secondary inner corner
turns = tg.turns_secondary
inner_corner = (np.array(label_dict['sec0']) + np.array(
(-conductor_width / 2., conductor_height / 2.)))
femm.ei_selectsegment(*(inner_corner +
np.array((0, -conductor_height / 2.))))
femm.ei_setsegmentprop('<None>', segment_length, 0, 0, 0, 'zero')
label_dict['ledge2corner'] = (inner_corner + np.array(
(0, ledge_height - conductor_height)))
femm.ei_addnode(*label_dict['ledge2corner'])
femm.ei_selectnode(*inner_corner)
femm.ei_movetranslate(cut_in_length, 0)
label_dict['edge2'] = (np.array(label_dict['sec0']) + np.array(
((-conductor_width + cut_in_length) / 2., 0)))
label_dict['edge2corner'] = inner_corner + np.array((cut_in_length, 0))
# Secondary outer corner
outer_corner = (np.array(label_dict['sec' + str(turns - 1)]) + np.array(
(conductor_width / 2., conductor_height / 2.)))
femm.ei_selectsegment(*(outer_corner +
np.array((0, -conductor_height / 2.))))
femm.ei_setsegmentprop('<None>', segment_length, 0, 0, 0, 'zero')
label_dict['ledge3corner'] = (outer_corner + np.array(
(0, ledge_height - conductor_height)))
femm.ei_addnode(*label_dict['ledge3corner'])
femm.ei_selectnode(*outer_corner)
femm.ei_movetranslate(-cut_in_length, 0)
label_dict['edge3'] = (np.array(label_dict['sec' + str(turns - 1)]) +
np.array(
((conductor_width - cut_in_length) / 2., 0)))
label_dict['edge3corner'] = outer_corner + np.array((-cut_in_length, 0))
# Set segment size for diagonal line to decrease mesh sizing
femm.ei_selectsegment(*label_dict['edge0'])
femm.ei_selectsegment(*label_dict['edge1'])
femm.ei_setsegmentprop('<None>', segment_length, 0, 0, 0, 'high')
femm.ei_clearselected()
femm.ei_selectsegment(*label_dict['edge2'])
femm.ei_selectsegment(*label_dict['edge3'])
femm.ei_setsegmentprop('<None>', segment_length, 0, 0, 0, 'zero')
femm.ei_clearselected()
# Round new edge on primary and secondary and set arcangle
for idx in range(4):
node = label_dict['edge' + str(idx) + 'corner']
femm.ei_createradius(node[0], node[1], corner_radius)
node = label_dict['ledge' + str(idx) + 'corner']
femm.ei_createradius(node[0], node[1], ledge_radius)
# Set arcsegment properties
segments = [
str(x) + str(y) + 'corner' for x in ['edge', 'ledge'] for y in range(2)
]
for s in segments:
femm.ei_selectarcsegment(*label_dict[s])
femm.ei_setarcsegmentprop(angle_max, '<None>', 0, 0, 'high')
femm.ei_clearselected()
segments = [
str(x) + str(y) + 'corner' for x in ['edge', 'ledge']
for y in range(2, 4)
]
for s in segments:
femm.ei_selectarcsegment(*label_dict[s])
femm.ei_setarcsegmentprop(angle_max, '<None>', 0, 0, 'zero')
femm.ei_clearselected()
# Set segment size to decrease mesh size along edge of PCB where the field
# is high
increase_pcb_mesh(cut_in_length, conductor_height, segment_length,
label_dict)
def assign_conductor(self, conductor):
assert self.problemType is ProblemType.ElectroStatic
self.select_periphery()
femm.ei_setsegmentprop('<None>', 0, 1, 0, 0, conductor)
self.clearselected()