IGBT Modules - Technologies, Driver and Application (Second Edition) - page 378

the set-up of a vibration test in which all three axis can be tested directly. To simulate
DC-bus capacitors andother components, weights have been fitted to thePCB.
This also illustrates that generally the entire system has to be considered. Not just the
module itself. According to the construction, resonances could develop whichmay lead
to destruction. Appropriate strengthening by additional mounting support is thus
exemplifies this with the excerpt of a mounting instruction for an
module. Further, the mounting instructions specify tightening torques
and stress forceswhichmay not beexceeded bothduring fitting aswell as in operation.
Fig. 10.12
Example of amounting instructionwith regard to the fixing points for load and
DC-bus terminals
10.3.2Gases and fluids
Commonly IGBT modules have a protection level of IP00
i.e. they do not offer any
protection against the penetration of solid foreign bodies (accidental contact) and/or
water. In this context "penetration" means: Access to the electrical contacts of the
module, as these are at a dangerous potential. Protection against accidental contact or
protection against penetrationby fluids is to beachieved by appropriatemeasures of the
construction, considering the requirements and standards of the final application.
However, the power semiconductors and the internal construction of the modules are
more or less protected by the housing against environmental influences. Here, of
course, the protection of hermetically sealed housings (e.g. moulded modules) is
affected best. In non-mouldedmodules the inside of themodule is encapsulated with a
gel and sometimes with an additional layer of epoxy
. However, if only
gel is used, which is standard today for the majority of industrial IGBT modules, these
modules are subject to certain restrictions with regard to environmental influences
(where they do not already corrode the case and its metallic parts). The silicone gel
used enables certain substances to cross (diffuse) and react with the copper of the
is an InfineonTechnologies protected trademark.
IP stands for Ingress Protection. The first digit details the protection degree against the penetration of solid
foreign bodies. These are grouped from 0 to 6, where 0 is unprotected and 6 is dustproof. The second digit
details the protection degree against penetration of water with detrimental effects. This is grouped from 0 to 8
(sometimes 9) where here too 0 means unprotected. The figure 8 means that permanent immersion in water is
permitted. A 9, combined with additional information, means withstanding water from all directions with increased
Due to the additional complexity in production as well as the risk of contamination of other processes it is now
commonlyendeavoured to ban epoxy from theproduction process altogether.
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