Abstract:
Insulate gate bipolar transistors (IGBTs) are widely used in electric vehicles,
railway locomotive and new generation aircrafts, due to the IGBTs have
advantages in small conduction resistance and small drive current. Hence, the
reliability of IGBTs directly affect the reliability and performance of these vehicle
systems. In recent years, a series of research works about IGBT reliability,
failure mode and ageing analysis have been carried out widely, and a suitable
prognostics method for IGBT and an efficient algorithm for predicting the IGBT
Remaining Useful Life (RUL) become increasingly important.
In recent years, despite the research works on IGBT reliability, failure mode and
effect analysis are carried out widely, the prognostics and prediction of the IGBT
remaining useful life are still the bottleneck in the research work to develop
IGBT health management system.
In this thesis, a framework and algorithm of IGBT prognostics and RUL
prediction were developed. The research was based on the IGBT accelerated
ageing experiments. The IGBT ageing data were processed and analysed, and
the mechanism of the IGBT degeneration was studied. Additionally, the IGBT
degradation models were built to simulate the IGBT degeneration process
which were utilised to develop the prognostics algorithm for predicting the IGBT
RUL.
Gamma distribution model, Exponential distribution model, Poisson distribution
model and the combining distribution model were established, and Monte Carlo
simulation was utilised in the algorithm to compute the IGBT remaining useful
life. The collector emitter voltage (VCE) was used as precursor parameter in
prognosis to predict the RUL. Seven IGBTs were experimented in this
prognostics research.
The RUL prediction results were analysed and compared, and the prognostics
algorithm was developed and summarised. The accuracy of the RUL prediction
was presented, and the root mean square error was utilised to analyse and
compare the efficiency and applicability of different models. The study of the
IGBT prognostics and algorithm development were summarised and
demonstrated.
