With the advent of hybrid electric vehicles (HEVs) and electric vehicles (EVs) come an increasing need for power electronics. In this regard there is great anticipation for the practical application of SiC (silicon carbide)*1 technology, which features less loss during power conversion and superior characteristics than conventional Si (silicon) products. Our new module was developed by combining ROHM's SiC device technology with Honda R&D's high power module technology. It represents the world's first high-power module fully driven by SiC devices. Functionally, the inverter module incorporates a converter circuit (1-phase) and an inverter circuit (3-phase) in a single package for greater compactness.

Utilized to reduce total loss, SiC inverters contribute to increased miniaturization of cooling equipment and greater thermal management design flexibility due to significantly less heat generation. As a result, SiC inverters enable a fourfold increase in drive frequency over conventional technology when used in step-up converter applications, promising significant improvements in output volume and density by making peripheral components smaller and more lightweight. In addition, the superior high-temperature stability of SiC facilitates failsafe design in on-board applications. ROHM offers SiC SBDs (Schottky Barrier Diodes*2), with a chip size of 5.14 × 5.14mm, and 4.8 × 2.4mm MOSFETs. SiC devices have been shown to dramatically reduce switching loss, to approximately 1/7th that of Si-IBGT*3 devices (Photo 2).

Switching loss even in power modules has been reduced to approximately 1/4th or less than that of conventional Si devices (Fig. 1).

By applying these newly developed SiC high-power modules to HEVs and EVs one can expect significant improvements in efficiency with considerable reductions in both size and weight. As the technology progresses ROHM believes that even greater advancements in performance will be possible through refinements made to the structure of power modules that will enable them to take full advantage of the standalone performance of SiC-MOSFETs, as well as through greater miniaturization. ROHM will continue to expand its lineup of SiC devices to include switching power supplies, industrial equipment and other practical devices for power conversion that are expected to become essential in the field of power electronics (Fig. 2).