A comprehensive evaluation of SiC devices in traction applications

With the increasing attentions on electric vehicle (EV), hybrid electric vehicle (HEV) and Plug-in hybrid electric vehicle (PHEV), the significance of power electronics in traction power converter increased through the last decades. Having dominated for years, silicon is now reaching its material limits. As an alternative, wide band gap device such as silicon carbide (SiC) device received more attention. Market of SiC devices has been growing for years and major manufacture are now willing to participate in the SiC business. Physical properties gives SiC advantages over Si, such as high breakdown voltage, low drift region resistance, high temperature operation. For traction inverters, power loss in switches are discussed. It has been demonstrated that SiC devices have lower power losses than Si IGBT which also helps with the sizing and design of the heatsink. In DC-DC converters, the advantage of high switching frequency of SiC devices would have a hugh impact on the overall system for reducing the power loss, size of passive components and total weight. However, high cost, low productivity and reliability under harsh environment are problems facing by SiC devices currently and they are expected to be solved in the future.