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so far we've seen how to perform an
electro thermal analysis of an isolated
half bridge inverter by coupling answers
q3d extractor and an SAS ice pack
we also modified the design of the
inverter to increase its reliability in
this video we'll use the improved design
and create a triple IGBT power module
then we'll add a liquid cooling system
to dissipate the heat from the design
and run an electro thermal simulation
we'll duplicate our half bridge inverter
and create a triple inverter module and
q3d extractor first bring up the options
window
where this option is checked the
boundary and excitation z' in the design
are also duplicated along with the
geometry
press o to make sure we're in the object
selection mode then press ctrl-a to
highlight the entire geometry on the
draw ribbon click the command duplicate
a long line place the cursor near the
leftover text of the geometry when the
cursor changes to a square click to get
the first point will duplicate along the
z-axis
in the coordinate fields below enter the
translation distance for the duplicated
objects so type 0 in the DX field press
tab and type 0 in the dy field then
press tab and type the desired distance
in the DZ field press ENTER now in this
dialogue enter the total number of
objects this is a three-phase AC power
inverter so I'll make three copies
so here's the triple IGBT power inverter
module you can see the net assignments
are retained for all three inverters
open the solve setup window I'll define
the DC resistance only solution
open the Edit sources window set the
sources on the DC plus and the phase
terminals to 100 amps
copy this design will now paste this
design into a new ice pack session
now I'll create a liquid cooling system
to dissipate the heat from the design
you can create this object easily with
the primitives and modeler commands on
the draw tab from the material
assignment this is a water-based cooling
system enclosed by aluminum we linked
the e/m power losses from Q 3d extractor
to ice pack again the metal objects and
alloys like solder are the main sources
of Joule heat so we'll include them in
the thermal simulation this time we'll
select our triple IGBT power module and
Q 3d extractor as the source design
to model the airflow across the device
I've assigned opening boundary
conditions on the cabinet faces the
ambient temperature is 20 degrees
centigrade the inlet type is set to
velocity along the X direction at 1
meter per second the flow specification
is set to pressure for this boundary
to model the circulation of water
through the cooling system hell assigned
additional boundary conditions I'll
define an opening to the water inlet
port I set the inlet type to velocity
and I've specified the X velocity to be
negative 0,25 meters per second
I'll now define the boundary condition
for this port I've set the inlet pipe
flow specification to pressure and left
it at its ambient value so this port
will take up all the flow from the other
one
I've also defined to solve setup as
shown here
run the simulation now the current
density plot and the temperatures for
the triple-a GT t power module are shown
side-by-side
these temperatures for the power module
seemed reasonable the temperatures are
highest for the wire bonds potential
wire bond failures could decrease the
reliability of the IGBT power module the
mismatch in the coefficients of thermal
expansion for the aluminum nitride
aluminum and silicon materials in this
design could still cause reliability
issues the good news is that you've
reformed thermal induced information and
stress analysis of this power module and
ANSYS mechanical as shown here thanks
for watching
you
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