Die Current Balancing of a Press-Pack SiC MOSFET

The SiC MOSFET die is more sensitive to stray inductance than IGBT device. One of the key layout point for the SiC MOSFET module is that the stray inductance for each die should be kept consistent to realize the current balance. In this paper, a press-pack SiC MOSFET module with consistent stray inductance for each die is designed to realize balanced current sharing between the paralleled die. To experimentally detect the current distribution in the press-pack module, Rogowski coils based on printed circuit board are embedded to measure the current waveforms. How to design the PCB based Rogowski coils is investigated. Then its effective of the die current detection is verified with embedded Rogowski coils. It is shown that the press-pack design can ensure a balanced dynamic current sharing between the paralleled dies.

I. Introduction

Press-pack module is more reliable than wire-bonded power modules. Therefore, press-pack SCR module and IGBT modules have been used in HVDC and high-speed trains' traction applications. Since SiC MOSFET has many distinguish advantages such as high switching frequency, better thermal performance and high voltage ability than that of the silicon device, it has large potential in high power and high voltage applications in smart grid and railway etc. It is natural to explore press-pack SiC module to further increase the performance of SiC module.