Self-Supplied Isolated Gate Driver for SiC Power MOSFETs Based on Bi-Level Modulation Scheme

The present work proposes a solution for implementing an isolated gate driver for SiC power MOSFETs. The isolation capability, gate switching and power transfer to the isolated side features are accomplished by using a unique magnetic transformer. To avoid core saturation, the original PWM control signal is modulated with a high frequency square-waveform. The on and off times are modulated with two different amplitude signals, what eventually allows for a full range duty ratio operation, including continuous turn-on and off operation. The reconstruction of the original PWM signal at the secondary side of the driver is also based on simple circuitry. As a consequence, the driver based on the proposed scheme results in a very compact solution. This enables the integration of the driver in the power cell, therefore increasing the achievable power density of the final converter. The basic operation of the driver si shown, and the main results on a SiC MOSFET based prototype are presented, thus demonstrating the feasibility of the driver.