负载波动下IGBT损坏分析及驱动电路优化设计

通过对变频控制系统的4种常用驱动电路的工作特点进行分析,并从维修的角度总结了这些驱动电路的工作可靠性,结论是可靠性比较高的变频器的驱动电路能有效地隔离输出级对控制级的影响并能有效地吸收栅极的各种干扰信号。对IGBT建立了工作模型进行分析,认为当电机负载波动时,冲击电压会在IGBT栅极产生振荡电压信号,该电压信号能使本该截止的IGBT导通,结果造成上下桥的IGBT直通,导致IGBT损坏;提出优化的IGBT驱动电路结构,设计了一种可靠的驱动电路方案,通过实际使用证明,该驱动电路具有结构简单、运行可靠等优点。

Analysis of IGBT damage under load fluctuation and optimal design of driving circuit

Based on the characteristic analysis of four driving circuits widely used in frequency conversion systems,their reliability is summarized from the viewpoint of maintenance,and the conclusion is that the driving circuit of more reliable converter effectively isolates the influence of output signal on control signal and absorbs the disturbing signals at the grid of IGBT. The IGBT model is built and analyzed. The impact voltage caused by load fluctuation may produce vibrating voltage signal at the grid of IGBT,which makes the closed IGBT open and the current directly through the top and bottom bridge legs damages the IGBTs connected. An optimal design of IGBT driving circuit is presented and practice shows it is simple and reliable.