Reliable thermo-mechanical design of high voltage planar technology solutions for smart wind power modules
The developments of smart grid and green energy, in particular the use of wind generators and high voltage direct current transmission requires converters, which allow the transformation of high power at high voltage. High-power insulated-gate bipolar transistor (IGBT) modules are one key component of the hardware platform. In the project EHLMOZ a new buildup and interconnection technology based on silver sintering and electroplated copper interconnects has been developed, denoted as high voltage planar interconnect technology (HVPT). Advantages of the technology result mainly from the replacement of the bonding wires. In particular, no silicone potting is needed. Evaluations of short circuit cases have shown that the reduction of the amount of insulating material can significantly reduce explosion effects and hence, housing stability requirements. One aim of the investigations was to optimize the stress and fatigue behavior of the power stacks by simulation. Fully coupled electrical-thermo-mechanical finite element simulations were used to get realistic transient temperature loadings as well as mechanical stresses. Improved thermal performance of the HVPT could be shown. Simulation studies were made to minimize failure risks of planar structures based on damage modeling. Significant reliability improvements dependent on the materials and geometric features were achieved.