| In order to solve the environmental problems brought by traditional energy,the development of new energy and its related power industry has become the most important part of China’s future development plan.With the increasing proportion of new energy,higher requirements are put forward for the reliability of new energy production and application.The power converter device with IGBT module as the core is an indispensable key equipment in the production and application of new energy.Its reliability will directly affect the stable operation of the whole system.In the fault statistics of power converter,the fault caused by IGBT module failure accounts for 31%,which is the most vulnerable link in the power converter.Therefore,improving the operation reliability of IGBT module,carrying out the research on the device failure mechanism with IGBT module as the core,and realizing the accurate monitoring and evaluation of module status are of great significance to ensure the operation stability of the equipment and even the whole system.Bonding wire failure is one of the main causes of IGBT module failure,and the module failure caused by its failure accounts for 70%.Therefore,taking the bonding wire of IGBT module as the research object,starting from the basic structure of IGBT module,this paper studies the problem of bonding wire lift-off position ignored in the failure mechanism of the bonding wire,and deeply analyzes the influence of bonding wire lift-off position on the electro-thermal characteristics of IGBT module through theoretical analysis,simulation modeling and experiment;Secondly,the specific collector current characteristics of IGBT module are deeply studied,the relationship between the number of bonding wires failed and the specific collector current amplitude is analyzed,and a bonding wire condition monitoring method based on the specific collector current drift characteristics is proposed.The specific research contents of this paper are as follows.(1)The on-state power loss model of IGBT is established,and the influence of the lift-off position of the bonding wire on the on-state power loss of the module is analyzed.First of all,the mechanism of bonding wire failure of IGBT module is explored in detail by means of theoretical analysis.Then,taking the FF450R17ME4 module produced by Infineon as the research object,the equivalent circuit is established according to the actual packaging circuit structure of the module,and the on-state power loss model of the upper bridge circuit of the module is built.Based on the established on-state power loss model,the instantaneous on-state power loss changes of the bridge circuit on the module at different lift-off positions of the bonding wires when one to three wires lift-off are calculated one by one.Finally,the viewpoint that the difference of the bonding wire lift-off position has an impact on the operation of the module is put forward.(2)The finite element simulation model and experimental platform are established to deeply study the influence of bonding wire lift-off position on the electro-thermal characteristics of the module.According to the actual geometric size of FF450R17ME4 module,the electro-thermal coupling model of IGBT module is built in COMSOL,and the electro-thermal characteristics of IGBT module under the different bonding wire lift-off positions are simulated and analyzed.It is found that the influence degree of the difference of the lift-off position increases with the increase of the number of the lifted-off bonding wires,and the junction temperature of the module under the centralized distribution of the lift-off position is higher,which is not conducive to the operation of the module.Then,an experimental platform based on IR camera is built to verify the accuracy of the simulation results.And the research conclusion provides a theoretical reference for the optimization of module packaging technology.(3)A condition monitoring method of IGBT module bonding wire based on the drift characteristics of the specific collector current is proposed.According to the conduction characteristics of IGBT chip,the theoretical basis that the conduction voltage drop of IGBT module is not affected by junction temperature under specific collector current is analyzed in detail.And then,the viewpoint of the drift characteristics of the specific collector current is put forward.Then,an experimental platform was built to measure the quantitative relationship between the specific collector current amplitude of the single chip branch of FF450R17ME4 module and the number of the lifted-off bonding wires,and verify the drift characteristics of the specific collector current.Finally,a method for monitoring the state of IGBT module bonding wire based on the drift characteristics is proposed,which provides a new method and idea for realizing the accurate monitoring and evaluation of IGBT module bonding wire state. |
PDF Full Text Request