基于输运系数的IGBT开通瞬态过程耦合规律分析

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

驱动回路和主回路参数共同决定了IGBT开通瞬态过程行为,分析驱动回路和主回路的耦合规律对于研究电路参数对瞬态过程的影响,以及开展IGBT状态监测研究具有指导意义。从功率器件非线性特征及其与电路参数耦合规律分析的基础上,通过输运系数建立主回路和驱动回路方程的关联并建立开通瞬态过程分析模型,比较器件电压与芯片电压的差异,分析电路参数变化对瞬态过程的影响。开通电流上升过程主要受驱动参数、测试电压和寄生参数的影响,测试电压影响输运系数进而影响电流上升速率。反向恢复过程主要受驱动参数、负载电流和寄生参数的影响,负载电流影响载流子抽取过程反向恢复电压上升速度。寄生电感对开通电流上升过程和反向恢复过程电流上升速度有抑制作用。驱动参数影响反向恢复电流上升速度,因此反向恢复过程是IGBT和续流二极管的共同行为。

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.