串联IGBT的一种复合均压方法

针对IGBT串联应用时的集射极电压均衡问题,提出并研究了一种门极平衡核与无源RCD缓冲电路相结合的复合均压方案。分析了门极平衡核的均压原理,借助门极驱动等效电路模型,导出了门极平衡核的参数设计方法。在IGBT门极与发射极之间引入瞬态电压抑制器,有效减缓了平衡核变压器的漏感与IGBT输入电容引发的门极信号振荡幅度,同时有效保护了IGBT门极过电压。建立了复合均压方案的仿真与实验系统,实验结果表明,复合均压方案对由于IGBT特性参数差异和门极驱动信号不同步而引起的IGBT集射极电压不均问题具有显著的平衡效果。

A Hybrid Voltage-Balancing Method for IGBTs Connected in Series

Aiming at the collector-emitter voltage-balancing issue for IGBTs in series connection,a new hybrid voltage-balancing method by combining the gate-balancing core(GBC) circuit with a optimized passive snubber circuit is presented.The operation principle of GBC is analyzed and GBC parameter design method is proposed with the help of IGBT gate driving equivalent circuit.A transient voltage suppressor is connected across the IGBT gate and emitter,so as to effectively mitigate the gate signal oscillation caused by GBC leakage inductance and IGBT input capacitance,as well as to protect the gate from over-voltage.A simulation and experimental system for the hybrid voltage-balancing scheme is implemented,and the results show that this hybrid scheme achieves excellent voltage-balancing effect for the causes of characteristics imbalance and gate signal timing imbalance of series IGBTs