Communication Functions for a Gate Driver Under High Voltage and High dv/dt

Abstract

The control of mosfet or IGBT transistors is carried out by a dedicated circuit called "driver", which is located as close as possible to the power module. It transmits switch-on and switch-off orders coming from the control unit and ensures the integrity of the component through safety functions. It also provides a galvanic isolation essential to guarantee the effective functioning of the system and the users' safety. Switching times of SiC mosfet are faster than Si IGBT, and SiC mosfet can also work under a greater dc voltage than Si mosfet. This involves the presence of higher dv/dt in the converter. In this paper, a communication function is studied to be integrated into the new generations of drivers for SiC MOSFET. The interest of the implementation of a communication system in a driver is presented. Currently available solutions on the market to provide isolation to communication channels are debated. The theoretical development of a solution called "CAN-ISO" is detailed and experimental results under a high peak voltage of 2 kV and a high dv/dt equal to 125 kV/μs are presented.