GE Industrial Solutions QBVE078A0S10R4 Barracuda Series - Manual (Page 9)

GE
Data Sheet
QBVE078A0S10R4 Barracuda Series; DC-DC Converter Power Modules
45-56Vdc Input; 10.4Vdc, 78.0A, 810W Output
January 15, 2014 ©2012 General Electric Company. All rights reserved. Page 9
Feature Descriptions (continued)
Thermal Considerations
The power modules operate in a variety of thermal
environments and sufficient cooling should be provided to
help ensure reliable operation.
Thermal considerations include ambient temperature,
airflow, module power dissipation, and the need for
increased reliability. A reduction in the operating
temperature of the module will result in an increase in
reliability. The thermal data presented here is based on
physical measurements taken in a wind tunnel.
Heat-dissipating components are mounted on the top side
of the module. Heat is removed by conduction, convection
and radiation to the surrounding environment. Proper
cooling can be verified by measuring the thermal reference
temperature (TH
2
).
Figure 16. Location of the thermal reference temperature
TH
2
for base plate module.
Peak temperature occurs at the position indicated in Figure
16. For reliable operation this temperature should not
exceed TH
2
=115°C. For extremely high reliability you can
limit this temperature to a lower value. The output power of
the module should not exceed the rated power for the
module as listed in the Ordering Information table.
Heat Transfer via Convection
The thermal data presented here is based on physical
measurements taken in a wind tunnel, using automated
thermo-couple instrumentation to monitor key component
temperatures: FETs, diodes, control ICs, magnetic cores,
ceramic capacitors, opto-isolators, and module pwb
conductors, while controlling the ambient airflow rate and
temperature. For a given airflow and ambient temperature,
the module output power is increased, until one (or more) of
the components reaches its maximum derated operating
temperature, as defined in IPC-9592B. This procedure is then
repeated for a different airflow or ambient temperature until
a family of module output derating curves is obtained.
Please refer to the Application Note “Thermal
Characterization Process For Open-Frame Board-Mounted
Power Modules” for a detailed discussion of thermal aspects
including maximum device temperatures.
Figure 17. Thermal Test Setup .
Increased airflow over the module enhances the heat
transfer via convection. The thermal derating of figure 18-
25 shows the maximum output current that can be
delivered by each module in the indicated orientation
without exceeding the maximum TH
x
temperature versus
local ambient temperature (T
A
) for several air flow
conditions.