IGBT驱动策略与仿真研究

发布时间：2018-01-04 03:03

本文关键词：IGBT驱动策略与仿真研究　出处：《华中科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着IGBT功率等级的不断提高,IGBT驱动策略面临着新的挑战,如高耐压值与开关速度间的矛盾、开通速度较慢与更早地检测短路状态间的矛盾、更大的电流下降速率带来更高的关断电压尖峰等。因此,研究能够优化IGBT开关过程、提升短路保护性能的IGBT驱动策略具有重要的意义。在本文中,对IGBT的工作机理及工作特性进行了介绍,使用双极传输理论对Hefner数学模型进行了详细推导,并将关断暂态模型中的耗尽层电容作为时间的函数,作出了修正。基于分析和推导结论,研究了包括闭环变电阻开关、dic/dt与集电极电压联合检测短路、基于变门极电压软关断的IGBT驱动保护策略。基于Saber建立IGBT仿真模型,对模型进行了静态特性仿真以及双脉冲测试仿真。利用该模型搭建了IGBT驱动仿真平台,对闭环、开环及不变电阻的开关策略进行了仿真对比;在不同短路情况下进行了短路检测策略仿真;在不同短路情况下进行了硬关断、软关断短路保护策略仿真对比。通过对建立的IGBT模型进行静态、动态特性仿真并将结果与数据手册及同类模型对比,验证了所建模型具有较高的准确性。利用该模型进行了驱动保护策略仿真,仿真结果表明:闭环变电阻开关策略具有自动确定变电阻时刻、加快IGBT开关速度并减小功耗的优势;dic/dt与集电极电压联合检测短路策略能够对各种短路状况进行全面检测,并在dic/dt很大的情况下使检测短路的时刻提前;基于变门极电压的软关断策略可以大大降低短路关断电压尖峰并且不需要等待集电极电压稳定。
[Abstract]:With the continuous improvement of IGBT power level, the driving strategy of IGBT is facing new challenges, such as the contradiction between high voltage value and switching speed, the contradiction between lower turn-on speed and earlier detection of short-circuit state. Therefore, it is of great significance to study the IGBT drive strategy which can optimize the switching process of IGBT and improve the performance of short-circuit protection. The working mechanism and characteristics of IGBT are introduced, and the mathematical model of Hefner is deduced in detail by using the bipolar transmission theory. The depletion layer capacitance in the turn-off transient model is modified as a function of time. Based on the analysis and derivation, the closed-loop variable-resistance switch is studied. Dic/dt is combined with collector voltage to detect short circuit, and IGBT driver protection strategy based on variable gate voltage soft turn-off. IGBT simulation model is established based on Saber. The static characteristic simulation and double-pulse test simulation of the model are carried out. The IGBT driving simulation platform is built using the model, and the closed loop, open loop and invariant resistance switching strategies are simulated and compared. The short-circuit detection strategy is simulated under different short-circuit conditions. Through the static and dynamic simulation of the established IGBT model, the results are compared with the data manual and similar models. The simulation results show that the closed-loop variable-resistance switching strategy can automatically determine the variable-resistance time. The advantages of accelerating IGBT switching speed and reducing power consumption; Combined detection strategy of dic/dt and collector voltage can detect all kinds of short circuit and make the detection of short circuit ahead of time when dic/dt is very large. The soft turn-off strategy based on variable gate voltage can greatly reduce the peak of short-circuit turn-off voltage and do not need to wait for collector voltage stability.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN322.8

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