Design of soft start in self-powered circuit for IGBT power modules in series

Series-Connected insulated gate bipolar transistor (IGBT) is the important basis in the high voltage and power converter application. A long duration of the excessive inrush current occurs in self-powered circuit when IGBT power modules in series start working. A design method of soft start of self-powered circuit is presented in this paper. The rise time of voltage of the capacitance stored energy is extended, the inrush current is reduced and easing the current stress IGBT module in series and diode can withstand by this method. The simulation model of soft start is realized by Saber and experimental results are used to illustrate both correctness and defensiveness of the proposed method to reduce the inrush current, protecting IGBT module and diode in self-powered circuit.