The Characteristics Of Current Distribution On Paralleled Chips Inside Press-Pack IGBT Modules And The Method Of Current Balance

The press-pack IGBT module is a new type of high power electronic device. Compared with traditional soldered IGBT modules, the press-pack IGBT module have so many advantages,like high reliability, easy to connect in series, excellent heat dissipation and special "short-circuit failure mode", that it is widely used in HVDC Light, offshore wind turbines and train traction application. Currently, many scholars have done researches on traditional IGBT modules. But there are few scholars who have studied the parasitic parameters of a press-pack IGBT module and few thesises published. In view of developing and designing the press-pack IGBT module, the current balance between paralleled chips is very important to reliability and stability of IGBT module. In this thesis, equivalent circuit model of press-pack IGBT module is studied; parasitic parameters and the method of parameter extraction is also studied.The influence of the major parasitic parameters on the characteristics of current balance inside the press-pack IGBT module and the method of current balance have been studied.Firstly, the basic principle and semiconductor structure of IGBT is introduced. Based on package technology of IGBT, the common package methods of high power device are introduced, including IGBT modules and press-pack IGBTs. The structure, principle and the disadvantages and advantages of two package methods are introduced.Secondly, for the press-pack IGBT module of Westcode, the structure of the IGBT module is analyzed. And the equivalent circuit model of press-pack IGBT module is set up, with parasitic parameters and behavioral models of IGBT and FRD dies. By use of ANSYS Q3D Extractor 12.0, the parasitic parameters of the press-pack IGBT are extracted.Thirdly, based on the extraction results of parasitic parameters, simulation circuit is made under the software environment of Saber, and the influence of parasitic parameters on the current distribution between paralleled chips is analyzed. And the results are verified by the experiment.Finally, by the simulation and experiment of the current distribution inside the press-pack IGBT module, the optimization and improvement to layout of press-pack IGBT module is proposed. By use of symmetric layout, the symmetric parameters between paralleled chips inside the press-pack IGBT module is realized and the results of the simulation show that the current balance between paralleled chips is well satisfied. The research result can be used in the development and design of the press-pack IGBT module.