Calibration and Measurement of <i>V</i> _ce-<i>T_j </i> Correlation With Temperature Distribution of IGBT and Interconnections

Online junction temperature (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_j</i>) estimation for power semiconductor device insulated gate bipolar transistor is of great importance for reliability assessment and enhancement. Typically, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_j</i> can be online calculated using the pre-calibrated correlation with <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small>-state collector-emitter voltages (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ce</sub>) at loading current. However, the uneven temperature distribution inside the device during calibration is different from the conditions during operation. Uneven thermal distribution inside the device and self-heating of chips will cause significant estimation error by using the pre-calibrated <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_j</i> - <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ce</sub> correlation, as the voltage drop on interconnections will be different. In this article, a novel calibration method of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_j</i> - <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ce</sub> relationship under pulsewdith modulation operation of device is proposed. By varying the switching frequency with fixed heatsink temperature, adjustable self-heating conditions and temperature distributions inside the device can be recreated. Moreover, a group of new relationships between junction temperature, heatsink temperature and temperature of interconnections inside device are revealed. By using the discovered relationship, the influence of uneven temperature distribution on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ce</sub> can be compensated in a noninvasive way, which can achieve higher accuracy in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_j</i> estimation compared to the conventional method.