(TD=25o
C) to 600A (TD=125o
C). Because the carrier life
time of DM increases as the chip temperature increases, the
reverse recovery current peak value is proportional to the rise
in diode chip temperature. Because of the temperature of
IGBT and the external circuit parameters unchanging, the
two commutation speeds before time tb can be considered as
the same owing to the same vce voltage variation. The
waveforms of induced voltage veE under LeE are plotted in
Fig.5. When the diode temperature increasing from 25o
C to
125o
C. The voltage veE_NP decreases from 9V to 5V.
Furthermore, the veE_NP can be chosen as an appropriate
TSEP for the P-i-N diode temperature extraction. A three
dimensions (3D) database of veE_NP with variety of diode
temperature and load current under 1600V bus voltage is
built up as shown in Fig.6. Given the bus voltage, output
load current and the measured IGBT temperature, the
corresponding diode temperature can be looked up from the
3D database with initial calibration.