高压大功率晶闸管反向恢复物理过程建模与计算

Simulative modeling and calculation of reverse recovery physical processof high voltage and high power thyristor

为了从微观物理角度阐释大功率晶闸管反向恢复过程的内在机理,基于载流子运输方程和物理模型,结合晶闸管结构参数及边界初始条件,利用仿真软件SILVACO建立了晶闸管二维物理仿真模型.将该仿真模型与外电路拓扑结合,搭建了晶闸管反向恢复特性的器件电路混合模型,并对晶闸管模型的电压阻断特性和反向恢复电流特性进行数值模拟,验证了模型的有效性.仿真研究了工频电流条件下晶闸管内部载流子浓度和复合率的变化规律,结果表明在工频电流正向衰减阶段,基区俄歇复合率接近SRH复合率;在反向恢复过程中,SRH复合占主导地位.

In order to explain the intrinsic mechanism of reverse recovery process of high power thyristor,a 2D physical simulation model for thyristor was set up by using the simulation software SILVACO based on carrier transport equation and physical model,in combination with structure parameters and initial boundary conditions of thyristor.A device-circuit hybrid model for reverse recovery process of thyristor was built by combining the as-proposed simulation model with the external circuit topology.The voltage blocking and reverse recovery current characteristics of thyristor model were simulated to verify the effectiveness of as-proposed model.The variation law of carrier concentration and recombination rate in thyristor under power frequency current was simulated and studied.The results show that the Auger recombination rate of base region is close to that of shockley-read-hall(SRH)recombination rate in the forward attenuation stage of power frequency current,and the SRH recombination plays a leading role during the reverse recovery process.