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    Silicon carbide on the road to automotive electrification

    By Majeed Ahmad | January 2, 2017

     

    Higher voltages and currents increase power density while reducing switching losses. Image courtesy of Infineon Technologies.

    The automotive industry has long been focusing on the higher efficiency of the combustion engine and electrification of the drivetrain in hybrid and fully electric vehicles to meet CO2 emission goals. Now we finally see a tipping point with a greater availability of silicon carbide (SiC) chips that offer extremely low power losses and higher temperature resistance.

    Power semiconductors based on SiC materials offer greater efficiency than silicon-based diodes, IGBTs and MOSFETs because of inherently faster switching, which in turn, allows SiC devices to operate at higher frequencies while producing lower power losses.

    Another key factor in the inclination of car OEMs and Tier 1 automotive suppliers toward SiC materials is lower internal resistance and robust intrinsic-body chips that subsequently lead to significant savings in cost, size and weight of power subsystems.

    SiC chips are now promising tangible energy efficiency benefits in all three electrical blocks of hybrid and electric drivetrains:

    1. Main inverter: SiC chips offer dramatic improvements in the main inverter design for hybrid and electric vehicles with longer battery life and smaller and lighter power unit that also lead to lower cooling requirements.

    2. Battery chargers: SiC components are being employed in both onboard chargers and portable chargers, where they sustain much higher current, voltage, and temperature. Moreover, a more efficient power conversion leads to lighter designs and lower cooling requirements.

    3. DC-DC converters: SiC diodes and MOSFETs offer higher conversion efficiency because high-frequency transistors reduce the need for bigger size inductors. Furthermore, reverse recovery current is negligible in SiC chips.

    Chipmakers Infineon, Rohm, and STMicro are expected to launch more SiC chips in 2017 to accelerate automotive electrification.