Design Of 10kV/200A High Power Silicon Carbide MOSFET Hybrid Module

Currently some high-power applications of power electronics industry such as high-voltage inverter, solid state transformer and some other occasions use IGBT modules as the switching components. However, because of the low operation frequency of IGBT, the loss can’t be reduced as well as the volume of the unit, and the power density is obviously low. Silicon carbide (SiC) MOSFET as a new kind of wide band gap semiconductor device, is well known for the advantages such as high-temperature, high-frequency and high power density etc. Take advantages of SiC MOSFET in these lOkV applications, the loss and volume can be both cut and the power density can be lifted in a degree. However, due to the characteristics of SiC MOSFET structure and the level of fabricating technology, the power capacity of one single commercial SiC MOSFET device can only reach 1200V/50A. In order to utilize SiC MOSFET in middle-high power applications, it is a must to connect SiC MOSFETs in series-parallel connection. And the major challenges of series-parallel connection lie on how to assure static and dynamic voltage equalization and the driver signal consistencies; and how to solve the problems of the devices in parallel of the inconsistent in current and heat distribution between them.This paper designs and fabricates 3600V/100A sub-module with 1200V/50A SiC MOSFET dies based on the one external signal driver series topology. On the condition of that, this paper promotes a hybrid impedence balanced module structure with six sub-modules. Three sub-modules connect in series as a string, and two strings connect in parallel to make the hybrid module. The hybrid module contains thirty-six 1200V/50A SiC MOSFET dies, and it integrates driver and equalizing circuits. And the number of the driving signals can be reduced as less as six. The driving signal transmits through optical fiber, and by this way peripheral interference will be reduced. It is easy to get consistent driving signals to get ideal voltage equalization. Static blocking voltage of the module can reach 10kV, and the voltage is evenly distributed on each serial devices. Double-pulse tests are taken on the condition of 5400V/200A. Current flows through these two strings evenly. The drain-source voltages are clamped under safe value voltages. The switching-on time (drain-source voltage drop from 90% to 10%) is about 350ns, and the switching-off time (drain-source voltage rise from 10% to 90%) is about 150ns. Experiments results show that the hybrid module is easy to driven and can achieve good voltage equalization with fast switching speed.