Imbalanced voltage sharing during the turn-off transient is a challenge for series-connected silicon carbide (SiC) MOSFET application. This article first discusses the influence of the gate-drain discharge deviation on the voltage imbalance ratio, and its primary causes are also presented and verified by LTspice simulation. Accordingly, a novel active gate drive, which aims to compensate the discharge difference between devices connected in series, is proposed and analyzed. By only using the original output of the driving IC, the proposed gate drive is realized by implementing an auxiliary circuit on the existing commercial gate drive. Therefore, unlike other active gate drives for balancing control, no extra isolations for power/signal are needed, and the number of the devices in series is unlimited. The auxiliary circuit includes three sub-circuits as a high-bandwidth current sink for regulating switching performance, a relative low-frequency but reliable sampling and control circuit for closed-loop control, and a trigger combining the former and the latter. The operational principle and the design guideline for each part are presented in detail. Experimental results validate the performance of the proposed gate drive and its voltage balancing control algorithm.

中文翻译：

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具有栅极-漏极放电补偿的有源栅极驱动，用于串联 SiC MOSFET 中的电压平衡

关断瞬态期间的不平衡电压共享是串联碳化硅 (SiC) MOSFET 应用的一个挑战。本文首先讨论了栅漏放电偏差对电压不平衡率的影响，并通过LTspice仿真提出并验证了其主要原因。因此，提出并分析了一种新颖的有源栅极驱动器，旨在补偿串联连接的器件之间的放电差异。通过仅使用驱动 IC 的原始输出，通过在现有商用栅极驱动器上实施辅助电路来实现所提出的栅极驱动器。因此，与其他用于平衡控制的有源栅极驱动器不同，不需要额外的电源/信号隔离，并且串联的器件数量不受限制。辅助电路包括三个子电路，分别是用于调节开关性能的高带宽电流吸收器、用于闭环控制的相对低频但可靠的采样和控制电路以及将前者和后者相结合的触发器。详细介绍了每个部分的操作原理和设计指南。实验结果验证了所提出的栅极驱动及其电压平衡控制算法的性能。