The collector current model of the IGBT based on the gate charge

Abstract

In this study, a dynamic and static collector current (I_C) model of the IGBT based on the gate charge is proposed. The gate charge could be easily obtained by measuring the voltage across the gate mirror circuit capacitance, and the transconductance obtained from the I_C–V_GE curve is mainly used. This model does not need the device structure parameters such as doping concentration, length, and thickness, thus is low cost and highly convenient. First, the gate charge is derived by integrating the currents of the variable capacitors C_GE and C_GC during the turn-on and turn-off transients, and an analytical relationship between the dynamic I_C and Q_G is researched. Second, a static collector current I_C is established, and the gate charge is obtained through current integration during the period of the Miller capacitance plateau. The influence of the temperature on the static transconductance is studied, and the accuracy of the static current model is improved. Finally, the performance of the model is optimized with various voltages, temperatures, and currents. The experimental results reveal that the proposed model achieves a collector current error of less than 5.6 % under various operating conditions, which verifies the accuracy of the proposed model.