Research on Inrush Overcurrent Detection Based on IGCT Internal Resistance Characteristic

The inrush current of IGCT can be up to 30kA, which has a better inrush current tolerance than IGBT, so it has important applications in the fields of pulsed high magnetic field and pulsed power. The inrush current of IGCT is dozens of times higher than the steady state current, and it is difficult for the commonly used current sensors to measure these two kinds of current. For this reason, this paper proposes to use the internal resistance of IGCT as a sampling resistor to realize its current detection. First of all, this paper analyzes the characteristic of the IGCT device, and establishes the on-state equivalent model of the IGCT, as well as analyzes the change characteristic of the internal resistance of the IGCT. On this basis, the value of the internal resistance is determined, so as to obtain the linear relationship between the IGCT current and its voltage. Secondly, the voltage measurement circuit is designed in this paper, which can independently measure the IGCT turnon voltage and turn-off voltage. The detection of IGCT current can be realized by using this voltage measurement circuit. Finally, this paper and tests the IGCT voltage measurement circuit and analyzes the test results.