Variable Gate Resistance Drive Circuit Based on di/dt Feedback for IGBT

Abstract

To overcome the rigid control of the classical drive method which used fixed resistance to drive IGBT, a variable gate resistance drive method was proposed. This method detected the change rate of collector current through the parasitic inductor of the IGBT module, and the closed-loop feedback was used to control this rate of change. All the expressions between voltage overshoot , overcurrent and di/dt were derived. Based on these expressions, the di/dt feedback control was designed. The feedback circuit selected gate resistances with different resistance values to drive IGBT in various stages of the turn-on and off process. According to the simulation analysis, both switching time and loss were reduced ultimately. The current peak and overvoltage were controlled effectively, and the switching performance was improved.