Limited by low availability, high price, and poor switching performance of high-voltage power devices, connecting low-voltage devices in series to block much higher voltages is always an option. However, severe voltage unbalance during turn-off transient remains to be solved. Most of the existing methods designed for low-speed silicon (Si) insulated gate bipolar transistor (IGBT) cannot be directly transplanted to the series-connected silicon carbide (SiC) MOSFETs with high switching speed. To maximum the switching performance of SiC MOSFETs, an elegant implementation of adjusting driving signal time delay method is proposed. In addition, a simplified model during drain-source voltage rising transient is discussed to basically reveal features and problems of the series-connected SiC MOSFETs. The factors affecting the appropriate time delay are discussed as well, especially the influence of the load current. The simplified model and the implementation are both verified by experiments. Indeed, the proposed active voltage balancing control works well and has no penalty of sacrificing switching performance of SiC MOSFETs.

中文翻译：

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基于调整驱动信号时延的串联SiC MOSFET有源电压平衡控制

受高压功率设备的低可用性，高价格和差的开关性能的限制，始终可以选择串联连接低压设备以阻止更高的电压。但是，关断瞬态期间严重的电压不平衡仍有待解决。设计用于低速硅（Si）绝缘栅双极晶体管（IGBT）的大多数现有方法无法直接移植到具有高开关速度的串联连接的碳化硅（SiC）MOSFET。为了最大化SiC MOSFET的开关性能，提出了一种调整驱动信号时延方法的理想实现。此外，讨论了漏极-源极电压上升瞬变期间的简化模型，以基本揭示串联SiC MOSFET的特性和问题。还讨论了影响适当时间延迟的因素，尤其是负载电流的影响。简化模型和实现均通过实验验证。实际上，提出的有源电压平衡控制效果很好，并且不会牺牲SiC MOSFET的开关性能。