Aging Status Monitoring Method Of IGBT Module Based On EMI Signal

In recent years,with the rapid development of power electronics technology,power electronic devices are widely used in new energy vehicles,HVDC,aerospace,rail transit and other fields due to their excellent performance.As the core device of power electronic devices,power devices are the key to realize the power conversion of power electronic devices.Due to the harsh working environment of power electronic devices,the high reliability of power devices plays an important role in the safe and stable operation of the system.Insulated gate bipolar transistor(Insulated Gate Bipolar Transistor,IGBT)has become the most widely used power semiconductor device because of its high switching speed,high power density and low switching loss.Electromagnetic interference is inevitable in high-speed off power devices,but because it also belongs to the working process of power devices,it will couple the internal aging information of power devices.The same temperature-sensitive electrical parameters and other signals can also be used to monitor the aging of power devices.In this paper,the Buck converter composed of IGBT module is taken as the research object.by studying the relationship between the health state of IGBT module and electromagnetic interference signal,the relationship between solder layer hole and bonding wire fault of IGBT module and common mode conducted interference and radiated interference is established,and the complete monitoring of package aging of IGBT module through electromagnetic interference signal is realized.Specifically,the main research contents are as follows:1.Firstly,the package structure and aging form of IGBT module and the basic principle of EMI noise generation in Buck circuit are introduced,and the aging cause of package form and the influence mechanism of package aging on EMI noise are analyzed.This paper probes into the transmission path of differential mode interference current and common mode interference current in Buck circuit,and shows that the amplitude of common mode interference current is closely related to the void degree of module solder layer,and the important influence of the number of bond wire fracture on the amplitude of differential mode interference current,and expounds the influence of chip junction temperature on common mode conducted interference and how the change of differential mode interference current affects the amplitude of external radiation signal after bond wire breaking.2.An on-line monitoring method for void aging of solder layer in IGBT module based on the spectrum amplitude of common mode conducted interference signal is proposed.First of all,the influence of the void in the solder layer on the parasitic capacitance of the module is analyzed,which shows that the change of the parasitic capacitance of the module will affect the amplitude of the common mode interference current.Secondly,the influence of temperature change on common mode interference is explored,which shows that the amplitude of common mode interference is not affected by temperature in low frequency band.Finally,the void degree of solder layer of IGBT module is monitored by the amplitude of common mode interference current in low frequency band.3.An on-line monitoring method for the aging degree of IGBT module bonding wire based on radiation interference signal is proposed.Firstly,the influence of IGBT module bond wire fracture on parasitic inductance is analyzed,and it is concluded that the parasitic inductance increases with the increase of the number of bond wires breakage.Secondly,the influence of module parasitic inductance on differential mode interference current is studied,and the IGBT module is equivalent to magnetic dipole.Finally,the radiation interference signal amplitude of the near-field probe capture module is used to monitor the number of bond wires shedding.