Evaluation of 1.7 kV SiC MOSFETs for a Regenerative Cascaded H-Bridge Multilevel Converter Cell

High fidelity AC grid emulators allow early testing and qualification of various equipment under conditions close to those expected in reality. Realizing this at medium voltage high power level is associated with certain challenges, some of which are discussed in this paper. Medium voltage grid emulator based on the well-known four-quadrant Robicon topology is considered as platform for realization of the AC grid emulator. To achieve high resolution AC waveform with sufficiently high control bandwidth, SiC based cell design is compared with pure Si and Hybrid (Si+SiC) designs. Using SiC devices for the output H-bridge stage allows significantly higher switching frequencies, improving achievable control bandwidth and improving fidelity of emulator output voltage.