Selection of HV SiC MOSFET Modules for MVCHB for Distribution System Applications

AHMED RAHOUMA; DAVID PORRAS FERNANDEZ; GERMÁN G. OGGIER; JUAN C. BALDA; RAMBABU ADAPA

Congreso; 2023 IEEE Energy Conversion Congress and Exposition; 2023

Distribution system applications based on power electronics, including energy storage systems and STATCOMs, are experiencing rapid growth. These applications traditionally depend on bulky line-frequency transformers to connect with medium-voltage (MV) distribution systems. Alternatively, the MV cascaded H-bridge (MV-CHB) converter offers a transformerless solution by utilizing series-connected cells. The number of cells required is inversely proportional to the dc-link voltage of each cell. Utilizing high-voltage (HV) silicon carbide (SiC) MOSFET power modules reduce the requirement for a large number of cells. With the possibility of several options forthese HV modules, an extensive comparison is essential to select the most suitable module for a particular application. Consequently, an algorithm is proposed to investigate and evaluate various 13.8 kV, 8.5 MVA MV-CHB converter designs. The comparison is based on designer-selected figures of merit (FOMs), particularly system power losses, volumetric power density, gravimetric power density, and system power complexity. To classify these MV-CHB designs, a multiattribute decision-making (MADM) method is employed, considering the relative importance of each FOM. Based on this analysis, it is determined that the 3.3 kV and 6.5 kV SiC MOSFET-based MV-CHB designs exhibit the most favorable performance according to the selected FOMs.