Design of a Novel SiC MOSFET Structure for EV Inverter Efficiency Improvement

Abstract

Inverters for electric vehicle motor drive systems are essential in converting the battery's direct current into alternating current. Si(Silicon) IGBT that is commonly used in inverter modules have large Vce,sat and turn-off time due to p+ drain and tail current. Therefore, inverter modules consist of Si IGBT with relatively low efficiency. If we can use MOSFETs instead of IGBT in inverter modules, it is possible to achieve high efficiency because of short turn-off time and high operating frequency. Yet also has a problem; Si MOSFETs has large on-resistance compared to Si IGBTs. In this study, SiC(Silicon Carbide) was used to make MOSFETs instead of Si. Futhermore, an accumulation channel concept is adapted to a SiC trench MOSFET, namely Trench ACCUFET. Compared with conventional SiC trench MOSFETs, the novel SiC trench ACCUFET structure has not only lower on-resistance but also high breakdown voltage as shown by the simulation results. We fabricated the Trench ACCUFET for verification, and described improvements that is to be made.

The South Korean Silicon-Carbide Semiconductor Industry: An Emerging Powerhouse [Expert View]

“…As with some other countries, the Similarly, Hyundai Motor Company, one of the world's topfive manufactur ers of vehicles, has published its SiC power electronics work and developed intellectual property (IP), as shown in Figure 2. Two technical papers were presented at the 2015 Electric Vehicle Symposium that discussed a trench gate SiC MOSFET with an accumu lationchannel structure and an advanced junction barrier Schottky diode [7], [8]. Given the large automo tive application volumes, Hyundai is likely continuing to execute on inter nal SiC power semiconductor R&D programs for electric vehicle inverters.…”