Pumped 2-Phase Cooling as an Enabler for a Modular, Medium- Voltage, Solid-State Circuit Breaker

The design approach and development of a 12kVDC, 2000A two-pole bidirectional circuit breaker capable of interrupting 80 kA available fault current in less than 0.5ms (time to current zero) is described. The extremely fast total interruption time of a DC current all but dictated a purely solid-state approach. Strict requirements for efficiency (≥ 99.8%) and power-density (≥ 25kW/L) were driven by intentions for future shipboard power systems. A pumped 2-phase cooling approach provided tight isothermality control and voltage isolation which enabled these advances in efficiency and power-density.