This paper investigates limitations of passive voltage clamping based dc solid-state circuit breakers (SSCBs). There are two major contributions of this paper. First, it presents a unique quantifying study of limitations in metal oxide varistor (MOV) clamping based SSCBs in terms of gate voltage distortions and power shock. Second, it provides a comprehensive quantifying investigation of limitations in MOV and resistor-capacitor-diode (MOV-RCD) clamping based SSCBs regarding the power shock and response speed. For MOV based SSCBs, both gate voltage distortions and power shock during turn-off are extremely high, causing switch degradation/failure. For MOV-RCD clamping based SSCBs, a snubber capacitor is added to reduce d v /d t and power shock. However, this capacitor brings two main limitations: a) inevitable high transient power/energy shock at high-current interruption and b) low turn-off speed caused by high-inertia capacitor charging at low-current interruption. Two prototypes are implemented to illustrate limitations: a discrete SiC MOSFET-based 500 V/20 A SSCB, and a SiC MOSFET module-based 800V/100A SSCB. Experiments validate that the transient power shock can reach 256 kW at a 1.2 kA fault current interruption, which affects system reliability. Moreover, the response speed at a 100 A case (7.8 μs) can be 14 times slower than the 1 kA case (0.56 μs) due to the snubber capacitor charging process, which leads to inconsistent control and coordination of SSCBs.

中文翻译：

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基于无源电压钳位的固态直流断路器的局限性研究

本文研究了基于无源电压钳位的直流固态断路器 (SSCB) 的局限性。本文有两个主要贡献。首先，它对基于金属氧化物压敏电阻 (MOV) 钳位的 SSCB 在栅极电压失真和电源冲击方面的局限性进行了独特的量化研究。其次，它对基于 MOV 和电阻-电容-二极管 (MOV-RCD) 钳位的 SSCB 在电源冲击和响应速度方面的限制进行了全面的量化调查。对于基于 MOV 的 SSCB，关断期间的栅极电压失真和电源冲击都非常高，从而导致开关退化/故障。对于基于 MOV-RCD 钳位的 SSCB，添加了一个缓冲电容器以降低 d v /d t 和电源冲击。然而，这种电容器带来了两个主要限制：a) 在大电流中断时不可避免的高瞬态功率/能量冲击和 b) 在低电流中断时由高惯量电容器充电引起的低关断速度。实施了两个原型来说明限制：基于分立 SiC MOSFET 的 500 V/20 A SSCB 和基于 SiC MOSFET 模块的 800V/100A SSCB。实验验证，在 1.2 kA 故障电流中断时，瞬态电源冲击可达 256 kW，影响系统可靠性。此外，由于缓冲电容器充电过程，100 A 情况下（7.8 μs）的响应速度可能比 1 kA 情况下（0.56 μs）慢 14 倍，这导致 SSCB 的控制和协调不一致。