Studay On Electro-heat Parameters Time Series And Its Relevan With Failure Of IGBT Power Module

The exploitation of new energy resources has become a hot issue in technology field at present,and the use of power modules in it become more and more widely,however,the low reliability of power modules constrained the development of new energy power systems.Due to the volatility of the wind,solar,tide,power fluctuation produces heat that makes a big impact on the power modules continuously,which expedites the failing process and reduces its reliability.Therefore,find and build a model which can predict power module residual life(residual life of power module)accurately is the foundation of stable and sustained operation in new energy power generation system.Presently few relative research is carried out on the recession and reliability which caused by thermal shock,research has been going on in this paper around the prediction of IGBT power modules which are widely used in electric equipment.The main work is as follows:(1)The major types of IGBT's failures and damage mechanism have been studied and summarized.The three major failure types are shown below: Fatigue damage cumulative failure which is caused by thermal shock;electric failure which is caused by too harsh conditions;failure for other environmental conditions,such as Cosmic rays.Built upon this basic,the gradually changes between different internal materials and different structures has been accurately elaborated,which are caused by thermal shock.Analyze the different influences of internal material properties and electric parameters between power cycles and temperature cycles.(2)Thermal resistance is an important parameter to evaluate the thermal performance of the device.The major thermal resistance measuring methods of IGBT include thermal sensitive parameters method,infrared scanning method and thermocouple method.In thermal sensitive parameter method so many error factors introduced in the measurement process,so we can hardly obtained accurate junction temperature and thermal résistance;infrared scanning method will cause damage and the price of device is very expensive,the user requirements are high;thermocouples method need to open the package and will bring greater measurement error.Design structures using fiber optic sensors measured the thermal resistance of the junction temperature measurement system that can reduce measurement errors introduced during the middle and small footprint can be more accurate measurements of IGBT thermal resistance.(3)With the accelerated lifetime test platform,we can obtain the depredated and lifetime data of IGBT which work in different temperatures experimental conditions.Then life prediction model based on temperature cycles was constructed and it has higher prediction accuracy than the existing models.Using time series method analyze the depredated data of saturation voltage,then compared the forecasting accuracy of various methods,and proposed more accurate weighted moving average method.Then analyze thermal degradation data of IGBT with multinomial models theory and built the optimum heat resistance degradation model.This paper analyses the failure mechanism of IGBT power module in detail and design a system which is used to measure the thermal resistance of IGBT.Then construct a life prediction model based on temperature cycles.It is a foundation for the on-line prediction of key power modules in new energy power generation systems.