Performance Evaluation of Three-Phase, Two-Level Medium Voltage Power Stack Based on 10 kV SiC MOSFETs

The performance of a 50 kVA three-phase, two-level medium voltage power stack based on 10 kV SiC MOSFETs has been evaluated under varying load conditions, i.e. voltage- and current-levels, coolant temperatures, and switching frequencies. A calorimetric measurement method is applied to estimate the power stack losses and its equivalent power stack efficiency. Experimental results from an inductive load test setup show an equivalent power stack efficiency of 98.8% ± 0.56‰ at 6 kV DC-link voltage, 10 kHz switching frequency, and 40◦C coolant temperature with a maximum MOSFET junction temperature of less than 115◦C and thermal resistance of 0.38 K/W.