This paper presents the switching cell design for medium voltage (MV) flying capacitor (FCC) with emerging 10 kV SiC MOSFET using a 5-level FCC for the 13.8 kV MV grid as an example. The flying capacitors and decoupling capacitors design to achieve compact size, loop inductance reduction, high voltage insulation, and good scalability are discussed. The flying capacitor switching cell double pulse test (FCC-DPT) concept is proposed for switching evaluation. With detailed switching loop characterization and analysis, the switching speed of this 10 kV 20 A SiC MOSFET discrete device is pushed to exceed 100 V/ns. Hardware of the 5L-FCC phase-leg is built and experimental results up to 23 kV dc voltage are demonstrated.
