基于电热耦合模型和寿命预测的IGBT可靠性评估

IGBT Reliability Evaluation Based on Electro-thermal Coupling Model and Life Prediction

针对IGBT可靠性评估中结温与运行工况和工作特性紧密相关的问题,以及考虑寿命预测中受多因素的影响,基于IGBT结构及失效机理,提出基于电热耦合模型和Bayerer寿命预测模型的IGBT可靠性预测流程,并结合贵州大学城市配电网柔性互联关键设备及技术研究示范工程,以MMC和DAB换流器中IGBT模块为研究对象,建立其热网络模型并根据设备实际运行工况计算内部IGBT芯片、FWD功率损耗和瞬时结温;通过雨流算法提取温度循环获得IGBT结温统计特征,从而得到IGBT的寿命预测和可靠性评估相关参数,并与利用功率循环曲线计算的失效率进行对比,结果表明,考虑了工作运行状态并基于电热耦合模型和寿命预测模型获得的失效率更能反映IGBT的实际运行情况。

Aiming at solving the problem that junction temperature is closely related to operating conditions and operating characteristics in IGBT reliability evaluation and considering the influence of multiple factors in life prediction,this paper proposes the reliability prediction process of IGBT based on electro-thermal coupling model and Bayerer life prediction model on the basis of IGBT structure and failure mechanism.Combined with Guizhou University’s urban distribution network flexible interconnection key equipment and technology research demonstration project,with IGBT modules in MMC and DAB converters as the research object,the thermal network model is established and according to the actual operating conditions of the equipment,the power loss and instantaneous junction temperature of the internal IGBT chip and FWD are calculated.The temperature cycle is extracted by the rain-flow algorithm to obtain the statistical characteristics of the IGBT junction temperature,thereby obtaining the life prediction and reliability evaluation related parameters of the IGBT.And compared with the failure rate calculated by the power cycle curve,the results show that taking into account the operating state,the failure rate obtained based on the electro-thermal coupling model and the life prediction model and can better reflect the actual operating conditions of the IGBT.