Active Gate Driver for Dynamic Current Balancing of Parallel-Connected SiC MOSFETs

Abstract

In high-power applications, parallel connection of discrete silicon carbide (SiC) MOSFETs is necessary to increase the current rating. However, the unbalanced dynamic current during switching transient may cause unequal power loss and thermal distribution, which is a great challenge in parallel applications. In this paper, a dynamic current balancing method based on a new active gate driver (AGD) is proposed to improve the current sharing. The principle of the AGD is based on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">di/dt</i> feedback control and voltage controlled current source to adjust gate drive current of SiC MOSFETs. Therefore, the switching trajectory of the paralleled devices can be changed to achieve current balance. In addition, by using master-slave control strategy, the proposed AGD can be easily used for multiple paralleled devices. The double pulse tests are conducted to verify the effectiveness of the proposed AGD. For two paralleled devices, the turn-on and turn-off switching energy imbalances are reduced from 13.4% and 56.0% (12.1% and 52.9%) to 8.8% and 15.3% (8.0% and 8.8%) by the current source (current sink) circuit. For six paralleled devices, the degrees of turn-on and turn-off switching energy imbalances can be reduced from 21.8% and 16.1% to 11.8% and 7.8% by the proposed AGD. <fn fn-type="other" id="fn3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This work was supported by Key-Area Research and Development Program of Guangdong Province under Grant 2021B0101310004, and the research program sponsored by Eaton. (<i>Corresponding author</i>: <i>Junming Zhang</i>) Y. He, X. Wang, S. Shao, and J. Zhang are with the College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China (e-mail: ; ; ; ). </fn>