10 kV SiC Power MOSFETs and JBS Diodes: Enabling Revolutionary Module and Power Conversion Technologies

Abstract

The majority carrier domain of power semiconductor devices has been extended to 10 kV with the advent of SiC MOSFETs and Schottky diodes. Twenty-four MOSFETs and twelve JBS diodes have been assembled in a 10 kV half H-bridge power module to increase the current handling capability to 120 A per switch without compromising the die-level characteristics. For the first time, a custom designed system (13.8 kV to 465/√3 V solid state power substation) has been successfully demonstrated with these state of the art SiC modules up to 855 kVA operation and 97% efficiency. Soft-switching at 20 kHz, the SiC enabled SSPS represents a 70% reduction in weight and 50% reduction in size when compared to a 60 Hz conventional, analog transformer.

Design and development of a high-density, high-speed 10 kV SiC MOSFET module

“…These field plates shift the peak electric field from the air to the PCB, which has a higher breakdown field strength. The power density of the designed module is 7.0 W/mm 3 , which is 67 % greater than that of Wolfspeed's 3 rd -generation 10 kV, 240 A SiC MOSFET module [6]. …”

“…The module has a power-loop inductance of approximately 16 nH [6], which is a notable improvement compared to the 1 st -generation 10 kV, 120 A SiC MOSFET/JBS diode module [2], [3]. However, the power density of this latest 10 kV module (approximately 4.2 W/mm 3 [6]) can still be improved.…”

“…One notable difference between the two devices is that the 1 st -generation SiC MOSFET degraded during body diode conduction [4]. Consequently, in the first 10 kV, 120 A power module, antiparallel 10 kV SiC junction barrier Schottky (JBS) diodes were used to conduct reverse current [3]. Further, in order to ensure that the body diode did not conduct before the JBS diode, low-voltage Si Schottky diodes were placed in series with the SiC MOSFETs [3].…”

“…The 1 st -generation 10 kV SiC MOSFETs were packaged in a module that was based on a standard 140 mm × 190 mm footprint typically used for slower, lower-voltage Si IGBTs [2], [3]. Given the improved performance of the 3 rd -generation 10 kV SiC MOSFETs [1], new packaging technologies are needed in order to realize their full potential.…”

“…Consequently, in the first 10 kV, 120 A power module, antiparallel 10 kV SiC junction barrier Schottky (JBS) diodes were used to conduct reverse current [3]. Further, in order to ensure that the body diode did not conduct before the JBS diode, low-voltage Si Schottky diodes were placed in series with the SiC MOSFETs [3]. However, the 3 rd -generation SiC MOSFET does not suffer from this type of degradation, and can therefore be safely operated in the third quadrant [5].…”