def draw_guard_ring(distance, gap, radius, polarity, label_name, label_dict):
'''Draw circular shape of guard ring in the problem and add a label.
Args:
distance (float): distance in r-plane from edge of PCB to edge of
guard ring
gap (float): distance in z-plane from edge of PCB to edge of guard ring
radius (float): radius of the guard ring conductor
polarity (int): attach the gaurd ring to high side or low side.
Polarity higher than zero sets the guard ring to the upper side of the
dielectric. Else the guard ring is set to lower side.
label_name (str): name of this conductor that is stored in the label
dictionary
label_dict (dict): stores label coordinates
'''
max_angle = 1 # arc_section angle, affects finess of mesh.
# high or low side?
if polarity > 0:
origin = label_dict['PCB_prim']
origin = np.array((origin[2], origin[1]))
point1 = origin + np.array((radius + distance, gap))
point2 = point1 + np.array((0, 2 * radius))
in_conductor = 'high'
else:
origin = label_dict['PCB_sec']
origin = np.array((origin[2], origin[1]))
point1 = origin + np.array((radius + distance, -gap))
point2 = point1 + np.array((0, -2 * radius))
in_conductor = 'zero'
label_dict[label_name + 'surface'] = point1
# ei_drawarc(x1,y1,x2,y2,angle,maxseg)
# From manual: Adds nodes at (x1,y1) and (x2,y2) and adds an arc of the
# specified angle and discretization connecting the nodes.
femm.ei_drawarc(point1[0], point1[1], point2[0], point2[1], 180, max_angle)
femm.ei_addarc(point2[0], point2[1], point1[0], point1[1], 180, max_angle)
# Add label and block property to guard ring
label_coord = np.average((point1, point2), axis=0)
femm.ei_addblocklabel(*label_coord)
femm.ei_selectlabel(*label_coord)
femm.ei_setblockprop('<No Mesh>', 1, 0, 'guards')
femm.ei_clearselected()
label_dict[label_name] = label_coord
# Set boundry based on coordinates
# ei_setarcsegmentprop(maxsegdeg, ’propname’, hide, group, ’inconductor’)
# From manual: Set the selected arc segments to:
# Meshed with elements that span at most maxsegdeg degrees per element
# Boundary property ’propname’
# hide: 0 = not hidden in post-processor, 1 == hidden in post processor
# A member of group number group
# A member of the conductor specified by the string ’inconductor’. If the
# segment is not part of a conductor, this parameter can be specified
# as ’<None>’.
femm.ei_selectarcsegment(label_coord[0] - radius, label_coord[1])
femm.ei_selectarcsegment(label_coord[0] + radius, label_coord[1])
femm.ei_setarcsegmentprop(max_angle, 'None', 0, 'None', in_conductor)
femm.ei_clearselected()
def set_conductor_label(coords, label_name, label_dict):
'''Set a block label inside a square conductor and set label properties.'''
label_coord = (np.average(
(coords[0], coords[2])), np.average((coords[1], coords[3])))
femm.ei_addblocklabel(*label_coord)
femm.ei_selectlabel(*label_coord)
# No mesh is needed inside conductors
femm.ei_setblockprop('<No Mesh>', 1, 0, 0)
femm.ei_clearselected()
label_dict[label_name] = label_coord
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)
femm.ei_addblocklabel(110, 95)
femm.ei_selectlabel(0, -10)
femm.ei_setblockprop('dielectric', 0, 1, 0)
femm.ei_clearselected()
femm.ei_selectlabel(0, 50)
femm.ei_selectlabel(110, 95)
femm.ei_setblockprop('air', 0, 1, 0)
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 add_block_labels(tg, label_dict):
'''Add block labels to pcbs, air, isolation disc, isolation gel/liquid.'''
# Add block labels
# ei seteditmode(editmode)
# From manual: Sets the current editmode to:
# – "nodes" - nodes
# – "segments" - line segments
# – "arcsegments" - arc segments
# – "blocks" - block labels
# – "group" - selected group
femm.ei_seteditmode('blocks')
# ei addblocklabel(x,y)
# From manual: Add a new block label at (x,y)
# labels for the PCBs
coords = [2, tg.height_dielectric + tg.height_pcb_core / 2.]
femm.ei_addblocklabel(*coords)
label_dict['pcb_prim_label'] = coords
coords = [2, -tg.height_pcb_core / 2.]
femm.ei_addblocklabel(*coords)
label_dict['pcb_sec_label'] = coords
# label for the surrounding air
coords = [2, tg.height_dielectric * 2 + tg.height_gel]
femm.ei_addblocklabel(*coords)
label_dict['air'] = coords
# label for the dilectric gel or liquid surrounding the transformer
coords = [tg.radius_pcb + 2, tg.height_dielectric + tg.height_gel / 2.]
femm.ei_addblocklabel(*coords)
label_dict['gel'] = coords
# label for the isolation disc
coords = [2, tg.height_dielectric / 2.]
femm.ei_addblocklabel(*coords)
label_dict['isolant'] = coords
# Set material type for all blocks
# ei setblockprop("blockname", automesh, meshsize, group) Set the selected
# block labels to have the properties: Block property "blockname".
# automesh: 0 = mesher defers to mesh size constraint defined in meshsize,
# 1 = mesher automatically chooses the mesh density. meshsize: size
# constraint on the mesh in the block marked by this label. A member of
# group number group
femm.ei_selectlabel(*label_dict['pcb_prim_label'])
femm.ei_selectlabel(*label_dict['pcb_sec_label'])
femm.ei_setblockprop('fr4', 1, 0, 'None')
femm.ei_clearselected()
femm.ei_selectlabel(*label_dict['air'])
femm.ei_setblockprop('air', 1, 0, 'None')
femm.ei_clearselected()
femm.ei_selectlabel(*label_dict['gel'])
femm.ei_setblockprop('midel', 1, 0, 'None')
femm.ei_clearselected()
femm.ei_selectlabel(*label_dict['isolant'])
femm.ei_setblockprop(tg.material_dielectric.lower(), 1, 0, 'None')
femm.ei_clearselected()