Research On The Packaging Technology For Integrated Power Electronics Module

Power electronics system integration is a hybrid and complex work, Which involves several subjects such as material, mechanics, chemistry, informatics and so on. It can realize high power density, high efficiency, high reliability and low cost for power electronics system, and it is an important development orientation of power electronics technology.The package technology, which impacts on electrical, EMI and thermal characteristic of the module, is an important part of power electronics system integration. Packaging is considered as a central driver in future power electronics technology. In power electronics integrated system, the discrete parts are replaced by Integrated Power Electronics Modules (IPEMs). This dissertation will focus on the package technology of IPEM.The key technologies of Power electronics packaging such as thin-film & thick-film technology, structure and interconnecting technology, substrate technology are introduced and the existing three-dimensional packaging technologies for IPEM including thin-film power overlay technology, metal posts interconnecting technology, flip chip technology, dimple array interconnect technique and pressure pack technology are analyzed and compared in detail.An active IPEM is constructed by integrating common switching cell which consistently repeats itself in different converters with gate driver and so on. The Flip Chip technology (FCT), which is widely used in IC packaging, is introduced into the fabrication of three-dimensional packaged IPEM to construct Flip Chip IPEM (FC-IPEM). A FC-IPEM consisting of two ball grid array (BGA) packaged MOSFETs and the corresponding gate driver & protection circuits are fabricated. In FC-IPEM, the traditional wire-bond interconnection is eliminated and planar structure is replaced by three-dimensional structure. To increase the lifetime of solder joints, the method of solder paste pre-overlaying on PCB solder pads is proposed. Meantime, process parameters are controlled to ensure the assembly quality. The parasitic parameters are extracted for building the parasitic parameter model of the FC-IPEM using an impedance analyzer. A method of paralleling external capacitor is proposed to improve measurement precision of structural capacitance. The methods to improve the Electro-magnetic Compatibility (EMC) performance are proposed by analysising Electro-magnetic Interference (EMI) transfer path. A synchronous rectifier Buck converter using FC-IPEM is built to test the electrical performance. The excellent electrical performance of FC-IPEM is proved by the experimental results. One-dimensional thermal resistance network of the FC-IPEM is built, from which the main thermal resistance resource can be concluded. Temperature distribution simulation results of the FC-IPEM using FLOTHERM are included and the design strategies that optimize the thermal performance of the module are given. The package realizes three-dimensional heat dissipation and has better thermal management.Adopting modular power supplies to construct a secondary distributed power system can improve the reliability and quality of the high voltage DC electrical system of airplane. Phase-shifted zero-voltage-switching (ZVS) pulse-width modulation full-bridge converter is employed as the main circuit because of ZVS achievement for the switches, simple circuit and control. The surface mounting devices are used due to the difficulty of obtaining the two-side solderable chips. A 28V/36A prototype aviation modular power supply using three-dimensional stacked-layer structure is built. Non-interleaved structure is adopted in the transformer winding arrangement to obtain the larger leakage inductance. The power dissipations of the transformer and filter are analyzed to obtain the optimal design of the windings. In modular power supply, Al-based insulated metal substrate of high thermal conductivity is used. Meanwhile, planar transformer technology allows the modular power supply to be low-profile. The parasitic parameter model of the modular power supply is built and the optimization strategies of improving the EMC performance are proposed. The electrical experimental results are given. Finally, the temperature distribution simulation result using FLOTHERM is included. The package technologies of the aviation modular power supply can be extend to the design of the medium to high power supplies for communication and computer applications.