Dual-function gate driver for a power module with SiC junction field transistors

Driving a high-power module which is populated with several parallel-connected silicon carbide junction field-effect transistor chips must be done appropriately. Parasitic elements may give rise to oscillations during turn-on and turn-off. Fast and oscillation-free switching performance is desired in order to achieve a high efficiency. The key-issue in order to fulfill these two requirements is the design of a sophisticated gate driver. This paper proposes a dual-function gate-drive unit which is able to switch the module with an acceptable speed without letting the current and voltage suffer from significant oscillations. It is experimentally shown that turn-on and turn-off switching times of approximately 140 ns and 165 ns respectively can be reached, while the magnitude of the current oscillations is kept at an acceptable level. Moreover, using the proposed gate driver an efficiency of approximately 99.6% is expected for a three-phase converter rated at 125 kVA and having a switching frequency of 2 kHz.