Power cycling lifetime estimation of IGBT power modules based on chip temperature modeling
Ikonen, Mika (2012-12-11)
Väitöskirja
Ikonen, Mika
11.12.2012
Lappeenranta University of Technology
Acta Universitatis Lappeenrantaensis
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-265-355-0
https://urn.fi/URN:ISBN:978-952-265-355-0
Tiivistelmä
In this doctoral thesis, methods to estimate the expected power cycling life of power
semiconductor modules based on chip temperature modeling are developed. Frequency
converters operate under dynamic loads in most electric drives. The varying
loads cause thermal expansion and contraction, which stresses the internal boundaries
between the material layers in the power module. Eventually, the stress wears
out the semiconductor modules. The wear-out cannot be detected by traditional
temperature or current measurements inside the frequency converter. Therefore, it
is important to develop a method to predict the end of the converter lifetime.
The thesis concentrates on power-cycling-related failures of insulated gate bipolar
transistors. Two types of power modules are discussed: a direct bonded copper
(DBC) sandwich structure with and without a baseplate. Most common failure
mechanisms are reviewed, and methods to improve the power cycling lifetime of the
power modules are presented. Power cycling curves are determined for a module with
a lead-free solder by accelerated power cycling tests. A lifetime model is selected and
the parameters are updated based on the power cycling test results. According to
the measurements, the factor of improvement in the power cycling lifetime of modern
IGBT power modules is greater than 10 during the last decade. Also, it is noticed
that a 10 C increase in the chip temperature cycle amplitude decreases the lifetime
by 40%.
A thermal model for the chip temperature estimation is developed. The model is
based on power loss estimation of the chip from the output current of the frequency
converter. The model is verified with a purpose-built test equipment, which allows simultaneous measurement and simulation of the chip temperature with an arbitrary
load waveform. The measurement system is shown to be convenient for studying the
thermal behavior of the chip. It is found that the thermal model has a 5 C accuracy
in the temperature estimation.
The temperature cycles that the power semiconductor chip has experienced are
counted by the rainflow algorithm. The counted cycles are compared with the experimentally
verified power cycling curves to estimate the life consumption based on the
mission profile of the drive. The methods are validated by the lifetime estimation of
a power module in a direct-driven wind turbine. The estimated lifetime of the IGBT
power module in a direct-driven wind turbine is 15 000 years, if the turbine is located
in south-eastern Finland.
semiconductor modules based on chip temperature modeling are developed. Frequency
converters operate under dynamic loads in most electric drives. The varying
loads cause thermal expansion and contraction, which stresses the internal boundaries
between the material layers in the power module. Eventually, the stress wears
out the semiconductor modules. The wear-out cannot be detected by traditional
temperature or current measurements inside the frequency converter. Therefore, it
is important to develop a method to predict the end of the converter lifetime.
The thesis concentrates on power-cycling-related failures of insulated gate bipolar
transistors. Two types of power modules are discussed: a direct bonded copper
(DBC) sandwich structure with and without a baseplate. Most common failure
mechanisms are reviewed, and methods to improve the power cycling lifetime of the
power modules are presented. Power cycling curves are determined for a module with
a lead-free solder by accelerated power cycling tests. A lifetime model is selected and
the parameters are updated based on the power cycling test results. According to
the measurements, the factor of improvement in the power cycling lifetime of modern
IGBT power modules is greater than 10 during the last decade. Also, it is noticed
that a 10 C increase in the chip temperature cycle amplitude decreases the lifetime
by 40%.
A thermal model for the chip temperature estimation is developed. The model is
based on power loss estimation of the chip from the output current of the frequency
converter. The model is verified with a purpose-built test equipment, which allows simultaneous measurement and simulation of the chip temperature with an arbitrary
load waveform. The measurement system is shown to be convenient for studying the
thermal behavior of the chip. It is found that the thermal model has a 5 C accuracy
in the temperature estimation.
The temperature cycles that the power semiconductor chip has experienced are
counted by the rainflow algorithm. The counted cycles are compared with the experimentally
verified power cycling curves to estimate the life consumption based on the
mission profile of the drive. The methods are validated by the lifetime estimation of
a power module in a direct-driven wind turbine. The estimated lifetime of the IGBT
power module in a direct-driven wind turbine is 15 000 years, if the turbine is located
in south-eastern Finland.
Kokoelmat
- Väitöskirjat [1037]