一种改进的并联IGBT模块瞬态电热模型

在大功率系统中,为了扩大电路的功率等级,开关器件往往会并联使用。为了保证绝缘栅双极型晶体管(IGBT)模块工作在安全范围,需要建立并联器件的瞬态电热模型。首先,重点分析了结温变化对损耗产生的影响,通过建立不同开关阶段等效电路分析推导电压、电流变化规律。同时,通过搭建测试电路得出受温度影响的参数与温度之间的定量关系。其次,在考虑并联器件之间的散热路径耦合基础上,提出并分析了一种改进的IGBT并联热阻抗模型。最后,基于损耗模型和热阻抗模型建立IGBT并联电热模型。搭建实验平台比较不同模块安装距离对瞬态结温的影响。与传统模型比较,计算结果与实验测试结果吻合,验证了改进的电热模型的准确性。

An Improved Transient Electro-Thermal Model for Paralleled IGBT Modules

In high power systems, the switching devices are usually utilized in parallel in order to scale up the power rate of circuits. A transient electro-thermal model of paralleled modules needs to be established to keep insulated gate bipolar transistor (IGBT) modules operating in the safe area. Firstly, the influence on losses by junction temperature is analyzed in detail. The variations of voltage and current are derived by building equivalent circuits in different switching periods. Meanwhile, the quantitative relationship between temperature-sensitive parameters and junction temperature is determined by building test platform. Furthermore, considering the coupling thermal path between paralleled modules, an improved thermal model for paralleled modules is proposed and analyzed. Finally, an electro-thermal model is built based on loss analysis and thermal model. The experimental platform was built to analyze the influence of distance between the modules on the transient junction temperature in paralleled modules. Compared with traditional models, the calculation results agree well with the experimental results, which validates the proposed model.