<i>In Situ</i> Insulated Gate Bipolar Transistor Junction Temperature Estimation Method via a Bond Wire Degradation Independent Parameter Turn-OFF <i>V</i> <sub>ce</sub> Overshoot
Yanyong Yang, Pinjia Zhang
Abstract
Fast and accurate online monitoring of junction temperature of insulated gate bipolar transistor (IGBT) chips is of great significance for overtemperature protection and thermal stress optimization of IGBTs. However, existing IGBT junction temperature estimation methods have drawbacks of dependence on bond wire degradation, low resolution, nonlinearity, and difficulty in online implementation. In this article, a novel <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> IGBT junction temperature estimation method via turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> collector voltage overshoot is proposed, which is independent on bond wire degradation. Based on theoretical analysis, the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> collector voltage overshoot is approximately linear to the junction temperature. The peak value of the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> collector voltage can be extracted during operation. Experiments are conducted to verify the technique proposed. A linear relationship between collector voltage overshoot and IGBT junction temperature is revealed, which illustrates the validity of the proposed method. Besides, the operation parameters (bus voltage, load current, and temperature) are considered, and the calibration on operation parameter variations is discussed. At last, the proposed method is compared with a traditional IGBT junction temperature estimation method based on the <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> -state voltage drop. The advantages of the proposed method lie in its independence on bond wire degradation and high resolution for online temperature estimation.