(Invited) 75 kVA 1kV DC 50 kHz Air-Cooled Inverter with 1.7 Kv SiC Mosfet and 3D-Printed Novel Modular Packaging Structure

Abstract

In recent years, some air-cooled inverters have been developed and demonstrated for grid applications using SiC power modules. All of these SiC power modules utilize the conventional single-side wire-bonding packaging structure, i.e. only one side of the power module is attached to heat sinks. The potential of silicon carbide (SiC) devices, such as high power density, high frequency and high temperature operation, have not been fully explored yet. To deal with this issue, several research efforts have focused on the development of SiC power modules with double sided-cooling capability, utilizing planar packaging structure . These power modules are able to achieve a comprehensive improvement in overall volume / size, parasitic parameters, as well as thermal impedance. However, some key aspects limit the real application of planar packaging structures. One main reason is that double-side solderable SiC devices are generally not commercially available. Other challenges include interconnection alignment issue, limited choices for die-attach material, complicated fabrication process, etc With the goal of exploring SiC device potential without complicated packaging, an all-SiC air-cooled wire-bonding power module and inverter is developed for grid applications based on 3D printing technology enabling: new packaging structure, optimized heat sink, and more-compact system integration.This paper presents the design and development of an 75 kVA, 50 kHz, 1kV air-cooled Silicon Carbide inverter using advance packaging and additive manufacturing technology. Specifically, an air-cooled power module with a new packaging structure is design, aiming at reduced thermal resistance for high temperature and high-power density operation. The detailed research work involves the design of a new packaging structure, wire-bond SiC power module design and fabrication, as well as associated power stage and control circuit design. The total volume of the power module for the prototype is 99725 mm3 a 48% volume reduction volume compared to previous work reported by the authors. The air-cooled module assembly incorporates three major parts: SiC MOSFET phase leg module with split high side and low side switches, a gate driver with cross-talk and short circuit protection functions, and 3D printed module package. In addition , the thermal performance of the inverter is also evaluated and the results show the maximum junction temperature of the bare die is 103C. Based on the air cool module, a 50-kW three phase inverter is developed and tested to further verify the superior thermal performance of the proposed packaging structure. The experimental results show that the peak efficiency is 99.1% at 1kV,50 KHz switching and 50 kW operating condition. Figure 1