分立型功率MOSFET结温估计的非线性热网络模型和参数辨识方法  

Nonlinear Thermal Network Model and Parameter Identification Method for Junction Temperature Estimation of Discrete Power MOSFET

作　　者：万萌[1] 应展烽[1] 张伟 Wan Meng;Ying Zhanfeng;Zhang Wei(School of Energy and Power Engineering Nanjing University of Science and Technology Nanjing 210094 China)

机构地区：[1]南京理工大学能源与动力工程学院

出　　处：《电工技术学报》2019年第12期2477-2488,共12页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金青年基金(51607091);智能电网保护和运行控制国家重点实验室开放基金课题(SGNR0000GZJS1705881)资助项目

摘　　要：分立型功率MOSFET是一类重要的电力电子器件,结温估计对于其安全运行具有重要意义。传统结温估计模型将功率器件壳温测量值作为解算的边界条件,对温度传感器安装可靠性要求较高,故当其应用于体积小巧的分立型功率MOSFET时,所得结温估计结果容易因传感器脱落而不可靠。为此,该文提出针对分立型功率MOSFET结温估计的非线性热网络模型。该模型利用较易测量的功率器件环境温度作为边界条件,计及非线性热对流和热辐射作用,有效描述器件与环境之间的换热过程。为克服模型热参数难以获取问题,提出模型参数的辨识方法,证明了辨识目标函数的凸函数特性。利用原对偶内点法,获得参数辨识的全局最优解,有效确定模型热参数。相关实验表明,所提模型能够在壳温测量不可靠时,提高分立型功率MOSFET结温工程估计的可靠性。Discrete power MOSFET is an important kind of power electronic device and its safe operation is heavily dependent on the junction temperature estimation.Traditional junction temperature estimation model has high requirement for reliability of case-temperature sensor installation,since the measured case temperature of power device is used as the boundary condition of junction temperature estimation.Therefore,the estimated junction temperature of traditional model could be unreliable,when the temperature sensor falls off from the discrete power MOSFET whose package size is relatively small.To address this,a nonlinear thermal network model for junction estimation of discrete power MOSFET was proposed in this paper.In the proposed model,the ambient temperature of power MOSFET,which can be measured more reliably,was used as the boundary condition of junction temperature estimation.The nonlinear heat convection and heat radiation were taken account into the proposed model to describe the heat transfer between the power MOSFET and ambient space.In order to determine the thermal parameters in the proposed model,a parameter identification method was presented.The objective function in this identification method was mathematically proved to be a convex function and the prime-dual interior point method was employed to obtain the globally optimal solution of objective function.Several experiments indicate that the proposed model can improve the reliability of discrete power MOSFET junction temperature estimation when case temperature measurement is not reliable.

关 键 词：分立型功率器件 结温估计 非线性热网络模型 参数辨识 原对偶内点法 

分 类 号：TM46[电气工程—电器]