Assessing the Impact of SiC MOSFETs on Converter Interfaces for Distributed Energy Resources

Distributed energy resources (DERs) are becoming integral components of electric power distribution systems. In most cases, an isolated dc-dc converter forms part of the interface required to connect the DER output to the distribution system. Operation of the converter at high switching frequencies results in size reduction of passive components at the expense of increased switching losses. However, silicon carbide (SiC) power devices have the potential of operating at high switching frequencies without significant loss penalty because of their fast switching times and ability to work at high temperatures when compared to similar Si devices. SiC diodes have already displayed the ability to offer more ideal diode behavior than Si diodes. Engineering samples of SiC MOSFETs are depicting lower switching losses and conduction losses over Si MOSFETs. This display is making SiC devices attractive for dc-dc converters used to connect DERs to the distribution system. This paper particularly deals with the design of a 300-W 100-kHz dc-dc full-bridge converter using zero-voltage zero-current switching for comparison of SiC MOSFETs and diodes against Si MOSFETs and diodes.