Comparative Experimental Evaluation of Zero-Voltage Switching Si Inverters and Hard-Switching Si and SiC Inverters

Several efforts have been put in the reduction of the power losses of DC-AC converters by investigating soft-switching topologies, which have been reported to boost efficiencies of silicon inverters up to 99%. However, the auxiliary circuits of the switches significantly impact on the circuit complexity. Conversely, the use of wide-bandgap devices offers an alternative for the reduction of the losses, while keeping the simple structure of a traditional inverter. This paper aims to experimentally evaluate the performance of four prototypes in terms of efficiency and costs. Two zero-voltage switching inverters, differing only in the power switches, and two comparable hardswitching inverters, mounting both silicon and silicon carbide devices, have been built and compared. Overall, the softswitching inverters allow improving the efficiency at high output current in comparison to hard-switching Si inverters, but their efficiency is comparable to that of SiC inverters or even lower at low output currents. The economic analysis has shown that the cost of the power stage of the soft-switching inverters and the hard-switching SiC inverter is about 2.5 and 1.5 times that of the hard-switching inverter based on Si IGBTs, respectively.