Turn-Off Strategies of IGBTs with Desaturation Bias Voltage to Fully Closed-Loop Control

This paper proposes a fully closed-loop control strategy for the turn-off process of insulated gate bipolar transistors (IGBTs) based on desaturation bias voltage, aiming to solve the problem of limited bandwidth in traditional closed-loop schemes. This strategy, by introducing a desaturation bias voltage, enables the IGBT to smoothly migrate from the saturation region to the active region with a wider dynamic response bandwidth before turn-off, achieving precise control over the turn-off process. The verification of the double-pulse test circuit based on a 1.2 kV/120 A IGBT module shows that compared with the traditional square wave bias scheme, the proposed hybrid wave scheme effectively reduces the desaturation loss.