Thermal Analysis of a Integrated Power
Electronics Module
MANE 6980
Nicholas Palumbo
12/05/2012
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IGBT
In order to determine losses of the integrated power electronics module, the design engineer
needs to determine which semiconductor device the module will make use of.
The main heat losses associated with this analysis are due to switching and conduction losses of the
IGBT.
Integrated power modules are used to power three phase AC motor drives. The figure below better
depicts the internal of the power electronics module. Switch 1,2,3,4,5, and 6 are in parallel.
The IGBT chosen for this application is the Powerex CM1800HCB-34N single IGBTMOD HVIGBT
Module, rated for 1800 Amperes and 1700 Volts.
The IGBT module consists of one IGBT transistor in a reverse-connected super-fast recovery freewheel diode.
The figure to the right depicts the model chosen for this analysis.
IGBT Module
IGBT Circuit Diagram
Semiconductor Losses
• IGBT power losses are divided into three groups:
conduction losses, switching losses and blocking losses
(which are normally disregarded).
• Conduction losses deal with a series connection of DC
voltage source of the on-state zero current of the
collector-emitter voltage and resistance.
• Switching losses deal with turn-on energy losses in the
IGBT taking into account the switch-on energy and the
switch-on energy caused by the reverse-recovery of the
free-wheeling diode; switching losses in the IGBT are
the product of switching energies and the switching
frequency.
IGBT Losses
IPEM Power Losses
6500
Losses of Transistor & Diode
6000
5500
Losses (Watts)
487.69 W
522.65 W
605.62 W
5000
4500
Losses
(.25 Derating)
4000
1972.00 W
3500
0.00
500.00
1000.00
1500.00
2000.00
Diode Recovery Losses
Transistor Conduction Losses
Diode Conduction Losses
Transistor Switching Losses
3000
2500
500
1000
1500
2000
Switching Frequency (Hz)
2500
3000
Cold Plate Physical Design
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Cold plate designs include two main categories based on piping configurations:
1. Series Piping
2. Parallel Piping
For this analysis three separate cold plate designs will be looked at to determine the best
configuration. Below are the three cold plate designs.
Option 1:
Series
Option 2:
Parallel
Option 3:
Parallel-Series
Pressure Drop Calculations
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Pressure drop calculations were completed for all cold plate designs.
The importance of a pressure drop calculation is based on the overall fluid system characteristics.
Pressure drop calculations were completed for each cold plate design. Graphs below are
representing pressure drop vs. cold plate piping distance.
Option 1: Series
Option 2: Parallel
4.96 PSI
2.67 PSI
Option 3:
Parallel-Series
7.6PSI
ANSYS Pressure Drops
• ANSYS pressure drops were completed for
cold plate option one and two.
Thermal Resistance Network
Thermal Resistance Circuit for Cold Plate Option One
Cold Plate Resistance
Breakdown
Thermal Resistance Circuit for Cold Plate Option Two
Temperature Profile of Cold Plates
110.00
105.00
100.00
95.00
90.00
85.00
80.00
75.00
70.00
65.00
60.00
55.00
50.00
45.00
40.00
35.00
30.00
Delta T w/
Thermal
Grease
Delta T w/
Sil Pad
0
0.005
0.01
0.015
0.02
Temperature Difference of Cold Plate Option
100.00
Two
0.025
Distance Along Cold Plate (m)
Temperature (oC)
Temperature (oC)
Temperature Difference of Cold Plate
Option One
95.00
90.00
85.00
80.00
75.00
70.00
65.00
60.00
55.00
50.00
45.00
40.00
35.00
30.00
Delta T w/
Thermal
Grease
0
0.005
0.01
0.015
0.02
Distance Along Cold Plate (m)
0.025
ANSYS Meshing of Cold Plate Option
One
ANSYS Thermal Results of Cold Plate
Option One
Meshing of Cold Plate Option Two
ANSYS Thermal Results of Cold Plate
Option Two
ANSYS Thermal Results of a Modified
Version of Cold Plate Option Two
Conclusion
Cold Plate
Cold Plate
Cold Plate
Option One
Option Two
4.96
2.67
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IGBT Operating Temperature (oC)
100.45
95.38
94.38
Heat Transfer Coefficient (W/m2K)
19509
12301
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Thermal Grease Temperature Change (oC)
1.16
1.16
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Sil Pad Temperature Change (oC)
11.26
11.26
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Al Plate Temperature Change (oC)
8.62
7.66
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Solder Interface Temperature Change (oC)
1.62
2.76
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7.04
3.69
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4.7
1.48
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5.17
1.63
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Moderate
High
Elevated High
Condition
Pressure Drop (psi)
Corrosion Resistant Steel Pipe Temperature
Change
(oC)
De-ionized Water Convective Temperature
Change (oC)
De-ionized Water Convective Temperature
Change w/ Fouling
(oC)
Construction Difficulty
Option Two
Modified