Survey and Experimental Evaluation of Voltage Clamping Components for Solid State Circuit Breakers

Abstract

The voltage clamping components or circuits are indispensable for both solid state circuit breakers (SSCBs) and hybrid circuit breakers (HCBs) to protect the solid state switch from over-voltage damage and absorb the remnant energy in the system loop inductances. To help the designers better select the suitable voltage clamping components or circuits for SSCBs or HCBs, this paper surveys and compares various voltage clamping components (e.g. metal oxide varistors, transient voltage suppression diodes, capacitor based snubber circuits, etc.) in terms of operating voltage ranges, surge current capability, energy absorbing capability, cost, etc. A voltage clamping component with lower peak clamping voltage is preferred for SSCBs, as the SSCB can operate at a higher DC bus voltage for a certain voltage rating (e.g. 1200V) solid state switch. The voltage clamping performances are also experimentally evaluated by measuring the ratio of peak clamping voltage and the maximum operating voltage (Vpk/Vop). Finally, the advantages and limitations of different voltage clamping components are discussed and summarized to facilitate the SSCB design.