Enhancing Turn-Off Performance in IGCT-Based High Power Applications—Part I: Anomalous High Current Turn-Off Mode and Safe Operating Area Expansion at Ultra-Low Voltage

Integrated gate commutated thyristors (IGCTs) are renowned for their low <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small>-state voltage and high surge current capability, but their limited ability to turn <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> current has historically limited their application. This article investigates an anomalous high current turn-<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> mode in IGCTs under ultralow voltage conditions. Through comprehensive theoretical analysis and simulation, it is demonstrated that IGCTs can achieve turn-<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> capabilities several times their rated current at ultralow voltage, defying the traditional requirement for strict gate commutation conditions. This discovery significantly expands the safe operating area (SOA) of IGCTs, offering a new perspective on optimizing their use in high-power applications. The findings presented here establish a foundation for the companion paper, which explores hybrid switch designs that further enhance IGCT turn-<sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> performance by leveraging this phenomenon.