Series connection of devices is an effective way to achieve higher blocking voltage. SiC MOSFETs exhibit narrow short-circuit withstand time and generally much lower short-circuit robustness than silicon IGBTs. This puts a critical concern on their utilization, further stressing the importance of reliable protection. A complete short-circuit protection should be implemented to improve the reliability. In this article, a systematic short-circuit analysis methodology is proposed. Following this methodology, all the possible fault scenarios can be derived. Besides the traditional short-circuit scenarios, some unique short-circuit faults, such as a single device short- or open- circuit, have been found in series-connected SiC MOSFETs. These unique faults may not cause overcurrent, which means the traditional overcurrent-based protection is not applicable. This article proposes a method combining drain-source voltage logic signal and gate signal to comprehensively detect both classic short-circuit scenarios and unique fault scenarios. Another different point in series-connected devices is that the soft turn-off should be synchronized for each serial device to prevent excessive voltage unbalancing. The proposed short-circuit protection scheme is evaluated under each short-circuit scenario. The experimental results demonstrate that the proposed protection scheme can successfully protect the serial devices from further destruction within 500 ns for all short-circuit scenarios.

中文翻译：

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串联 SiC MOSFET 的综合短路保护方案


器件串联是实现更高阻断电压的有效途径。 SiC MOSFET 的短路耐受时间较窄，并且通常比硅 IGBT 的短路鲁棒性低得多。这使得它们的使用受到严重关注，进一步强调了可靠保护的重要性。应实施完善的短路保护以提高可靠性。在本文中，提出了一种系统的短路分析方法。按照这种方法，可以得出所有可能的故障场景。除了传统的短路情况外，串联SiC MOSFET中还发现了一些独特的短路故障，例如单个器件短路或开路。这些独特的故障可能不会导致过流，这意味着传统的基于过流的保护不适用。本文提出了一种结合漏源电压逻辑信号和栅极信号的方法，以全面检测经典短路场景和独特故障场景。串联设备的另一个不同点是每个串联设备的软关断应该同步，以防止电压过度不平衡。所提出的短路保护方案在每种短路情况下进行评估。实验结果表明，所提出的保护方案可以在所有短路情况下在 500 ns 内成功保护串行设备免遭进一步破坏。