短路故障下直流固态断路器缓冲电路的设计

在低压直流微电网发生短路故障时，直流固态断路器(Solid-state circuit breaker, SSCB)可以快速有效地将故障区域隔离，然而它自身的安全可靠性依赖于缓冲电路。由于SSCB上的缓冲电路的侧重点是过电压抑制能力和故障能量的快速吸收，而不是减少缓冲电路的损耗，所以不能直接使用适用于变换器器件的传统缓冲电路设计方法。因此，提出一种拥有过电压抑制能力的SSCB缓冲电路的设计方法。针对放电阻止型RCD缓冲电路进行保护动作后缓冲机理分析，选定三种性能指标并给出详细的参数设计步骤，然后选定工况计算出合适的缓冲参数。最后通过实验验证了上述分析结果的正确性和放电阻止型缓冲电路的有效性。

Design of snubber circuit for DC solid-state circuit breaker in short-circuit fault

Under a short-circuit fault in low-voltage DC microgrid, the Solid-State Circuit Breaker (SSCB) can isolate the faulted area quickly and effectively, while its own safety and reliability depends on the snubber circuit. For the design of the snubber, however, traditional method suited for snubber of converter device cannot be directly applied, because the snubber for circuit breaker puts more stress on its overvoltage suppression and rapid absorption of fault energy instead of snubber loss reduction. Therefore, this paper proposes a design method for SSCB snubber circuit with overvoltage suppression ability. The snubber mechanism of discharge-suppressing type RCD snubber circuit after protection action is analyzed. Three performance indicators are selected and a detailed procedure for parameter design is proposed, then suitable snubber parameters are calculated after selecting working condition. Experiments are conducted finally to verify the correctness of the above analysis results and effectiveness of the discharge-suppressing type RCD snubber circuit. This work is supported by Science and Technology Support Program of Hubei Province (No. 2015BAA109).