Design And Thermal Stress Simulation Of 3300V/400A SiC Hybrid Module

As an important compenent of many decices, power electronic devices play an important role in improving energy efficiency, IGBT module becomes an important switch device. In view of shortage of traditional full silicon power module, hybrid module uses SiC diode as its freewheeling diode rather than traditional Si FRD, which can effectively reduce power consumption and enhance switching speed. With increase of voltage level and current capacity,poor heat dissipation, high thermal stress and uneven distribution have been a pressing problem to be solved. Therefore, finite element method is used to design and analyze thermal stress of 3300V/400A SiC hybrid module. The main research works and conclusions are as follows:1. The design of hybrid module is complished. The layout design of 3300V/400A SiC hybrid module's DBC board is completed by using eight 3300V/50A Si-IGBT and eight 3300V/50A SiC-JBS chips. The analysis and preliminary design of vertical(chip/DBC/substrate)structure's DBC,substrate,and solder are finished.2. Thermal analysis of hybrid module is achieved. The material and thickness of each layer of hybrid module's longitudinal structure are optimized preliminarily. In view of thermal failure problems in many modules, the three dimensional model of hybrid module is established, and the thermal field is simulated. The factors affecting thermal field distribution of hybrid module,such as material and thickness of substrate, lining plate, solder layer, are studied. Then the influence rules are summarized. After optimization, 8mm thickness of Cu material as substrate,2.5mm thickness of SiC material as lining plate, 0.1mm thickness of nano silver paste as lining solder layer and chip solder layer are used. The heat dissipation capability of hybrid module is increased by 35.1%,3. Thermal stress analysis of hybrid module is finished. The material and thickness of each layer of hybrid module's longitudinal structure are optimized further. Based on thermal analysis,thermal stress coupling analysis of hybrid module is carried out. Thermal stress analysis can simulate distribution of thermal stress field accurately. By integrating temperature field and stress field analysis, the optimal design of hybrid module is determined: 5mm thickness of AlSiC material as substrate, 1mm thickness of AIN material as lining plate, 0.1mm thickness of nano silver paste as lining solder and chip solder. And thermal stress of the optimized hybrid module can be reduced by 18.1%.