采用全阶状态观测器的IGBT模块结温预测

Predicting junction temperature of IGBT module based on full-order state observer

摘要:

为解决控制器功率器件过温失效问题,需要对IGBT的PN结温度进行实时精确估计。 设计全阶状态观测器对IGBT的结温进行实时估计,并综合考虑电、热参数的相互影响,采用闭环控制实现结温的估计修正；根据双脉冲测试原理搭建IGBT动态特性离线测试平台,研究导通电流、母线电压、结温对IGBT损耗的影响,采用线性插值法推导IGBT损耗的数学模型；根据热-电比拟理论建立热网络模型,搭建热阻测试平台获得温度与瞬态热阻变化曲线；基于IGBT热网络模型推导各温度节点的状态方程,针对开环估计方法估计精度差的问题,设计全阶状态观测器,利用观测器输出壳温和实测的壳温之间的误差对结温估计值进行实时修正。 搭建基于Matlab\\Simulink的仿真平台,验证了IGBT结温估计的有效性和准确性；搭建结温预测实验平台,采用热敏参数法对结温状态观测器进行验证。 仿真和实验结果表明,估计的结温能够很好地跟踪实际值,验证了提出方法的准确性。

Abstract:

To accurately estimate the junction temperature and solve the over-temperature problem, a junction temperature state observer is designed to predict the junction temperature of IGBT in real time considering the mutual influence of electrical and thermal parameters. First, the effects of conduction current, bus voltage and junction temperature on IGBT loss are studied on the offline test platform of IGBT. The mathematical model of IGBT loss was derived by linear interpolation method. Second, a thermal network model is built up based on the IGBT transient thermal resistance test platform. Last, the state equations of each temperature node are derived and a full-order state observer is designed to compensate the drawback of open-loop state equation. The error between output shell temperature and the measured shell temperature is corrected in real time on full-order junction temperature observer. To verify the effectiveness of the designed method, simulations carried out on Matlab\\Simulink and experiment setup are established. The simulation and experimental results show that the predicted junction temperature can track the target value, and the designed method is validated.