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Chair for Power Electronics and
Electromagnetic Compatibility
At Chemnitz University of Technology,
the Chair of Power Electronics and Elec-
tromagnetic Compatibility is responsible
for the education and research regard-
ing power devices, thermal-mechanical
problems of power electronic systems,
power circuits and electromagnetic com-
patibility.
Reliability and Ruggedness of Power
Devices
Ruggedness: Power devices must with-
stand overload conditions, they have to
be rugged. Short circuit capability of high
voltage IGBTs (SC I, SC II) is measured. A
further point is the surge current capa-
bility of Si and SiC diodes. The reverse
recovery behavior is of special interest.
Switching behavior and ruggedness of
high power diodes are investigated.
Experimental analysis goes along with
numerical device simulations. Detailed
analysis of the electro-thermal process-
es in devices leads to design suggestions
for improved ruggedness. Additionally,
the group offers failure analysis, includ-
ing opening of the power module for a
profound analysis and the preparation of
failure reports including evaluation. The
group cooperates with Fraunhofer ENAS
and can use optimal analysis tools, if nec-
essary.
Reliability: Power devices are tested for
their reliability and durability on eight
self-built power cycling stations, between
100A and 400A, up to 2000A are in con-
struction. Power cycling is the most im-
portant for life expectation of the devic-
es. Research work is focused on detailed
models for the failure mechanisms. Ther-
mal-mechanical simulations are applied
to illustrate local mechanical stresses and
strains in the device resulting from the
mismatch in the thermal expansion of the
material layers.
Additional reliability test stations are hot
reverse test (up to 2500V DC and 200°C)
and high-humidity high temperature
reverse bias test.
The group is involved in various nation-
al and international projects with glob-
al players from semiconductor indus-
try, with automotive industry regarding
electric and hybrid electric vehicles, in
large offshore wind power, in inverters
for solar plants. The research in different
projects is supported by industry part-
ners, SINTEF Norway, the EU, BMWi and
BMBF, DFG and ESF/SAB.
Chemnitz University of Technology
Simulation of current filaments in a high-voltage diode
Destruction of a power diode by a current filament
Bond wire lift-off created by power cycling
