Analysis of the Coupling Relationship of IGBT Turn on Transient Process Based on Transport Coefficient

The transient behavior of the IGBT turn on process is jointly determined with the parameters of the driving circuit and the main circuit. Analyzing the coupling relationship between the driving circuit and the main circuit has guiding significance for studying the influence of circuit parameters on the transient process and conducting IGBT state monitoring research. Based on the analysis of the nonlinear characteristics of power devices and their coupling with circuit parameters, the correlation between the main circuit and driving circuit equations is established through transport coefficient and a transient process analysis model is established. The difference between device voltage and chip voltage is analyzed, and the effects of circuit parameters on the transient process are analyzed. The current rise process is mainly influenced by the driving parameters, testing voltage, and parasitic parameters. The testing voltage affects the transport coefficient, which in turn affects the rate of current increase. The reverse recovery process is mainly affected by the driving parameters, load current, and parasitic parameters. The load current affects the speed of the reverse recovery voltage rise during the carrier extraction process. Parasitic inductance has an inhibitory effect on the current rise rate during the turn on and reverse recovery process. The driving parameters affect the rise rate of reverse recovery current, so the reverse recovery process is a common behavior of IGBT and freewheeling diode.