Modular Three-level T-type Power Electronics Building Block for Aircraft Electric-Propulsion Drives

The power electronics drives for electric propulsion in more-electric aircraft need to highly efficient and power-dense. Moreover, a modular approach to the drive’s construction ensures reduced costs, reliability, and ease of maintenance. In this paper, the design and development of a modular power electronics building block (PEBB) in a dc-ac three-level t-type single phase-leg topology is presented. The designed PEBB is capable of 100-kW power processing and suitable for 1-kV dc-link. A hybrid switch consisting of a silicon IGBT and silicon carbide MOSFET was used as the switching device in the PEBB. The hybrid switch enables high switching frequencies at high-power than the conventional silicon IGBT. A model-based design tool facilitated the topology and semiconductor selection for high conversion efficiency and lightweight. Due to the unavailability of commercial three-level t-type power modules, a PCB- and off-the-shelf discrete semiconductor-based high-power switch was designed for the neutral point clamping. A non-trivial design of an aluminum-based multilayer laminated busbar, a key element in the PEBB, was the primary focus of the work. The busbar had symmetrical low-inductance commutation loops, and the value was in the range of 28 - 29 nH. The block’s specific-power and volumetric power density were estimated to be 27.7 kW/kg and 308.61 W/in3, respectively. Finally, the block’s continuous operation was demonstrated at 48 kVA, and the efficiency of the block was 98.2%.