Double-Stage Gate Drive Circuit for Parallel Connected IGBT Modules

In more and more pulsed power applications solid state modulators are applied. There, often IGBT modules must be connected in parallel due to their limited power handling capability. For balancing the currents in the IGBTs a control method adapting the gate signal of the single IGBTs has been presented in a previous paper. Besides the current balancing also the fall and rise times of the voltages/currents are crucial as they significantly influence the pulse shape and the modulator efficiency. For reducing the rise time of the pulse without increasing the maximal over-voltage of the IGBT a double-stage gate driver for parallel connected IGBTs is presented in this paper. In this gate driver also protection circuits for avoiding over-voltages as well as over-currents are included and an improved current balancing method is incorporated. Finally, measurement results revealing the dependency of the rise time/turn off losses on the design parameters of the gate drive are presented.