IGBT驱动电路密勒效应的应对策略分析

Strategy analysis on Miller effect of IGBT driver circuit

IGBT的门极驱动电路影响IGBT的通态压降、开关时间、开关损耗、承受短路电流能力等,决定了IGBT的静态与动态特性。针对IGBT在开通和关断时,密勒效应对驱动的影响及其应对策略进行研究和分析。分析了密勒电容引起的寄生导通效应的4种应对策略,包括改变门极电阻,增加GE间电容,采用负压驱动以及有源密勒钳位技术,并分析了驱动电路中门极电阻对IGBT性能的影响。在此基础上,进行了实验对比,给出了实验分析结果。此外还对驱动与控制板的线缆连接要求进行了测试对比。实验结果表明,门极电阻的设置直接影响IGBT的开关性能,实际应用中需要综合考虑实际需求选择合适的门极电阻值来保证IGBT最优化地开通关断,密勒效应中的密勒电容对IGBT的开关性能影响非常大,驱动与控制板的线缆连接要求越短越好。

The gate driver circuit of IGBT affects on-state voltage drop,switching time,switching loss and capability bearing short-circuit current of IGBT,which determines the static and dynamic characteristics of ICBT. The influence of Miller effect on driver during the on-and-off of IGBT and the coping strategies are researched and analyzed. The four strategies corresponding to parasitic conduction effect produced by Miller capacitance are analyzed,including changing gate resistance,increasing capacitance between GE,using negative pressure drive and active Miller clamp technology. The influence of gate resistance in driver circuit on IGBT performance is also analyzed. On this basis,the contrast experiment was carried out. The experimental analysis results are given. The requirements of cable collection between the driver and the control panel are compared. The experimental results shows that the setting of gate resistance directly affects the switching performance of IGBT,the practical demand needs to be considered to select an appropriate gate resistance value for ensuring the optimization of IGBT on-and-off in the practical application,the Miller capacitance in Miller effect has a great influence on the switching performance of IGBT,and the cable collecting the driver and the control panel should be as short as possible.