SiC MOSFETs adopted in inverter brick and now in mass production

ROHM and Schaeffler have begun mass production of a new high-voltage inverter brick equipped with ROHM’s SiC MOSFET bare chips as part of their strategic partnership. The inverter brick is intended for a major Chinese car manufacturer.

The Schaeffler inverter subassembly is the vital power device building block (brick) to control the electric drive via logic signals. This is where the high-frequency current pulses are produced that set the vehicle’s electric motor in motion. The performance characteristics of the inverter brick now being made are impressive: Schaeffler increased the output of the brick by increasing the maximum possible battery voltage to much more than the usual 800V, and with RMS currents of up to 650A, which turns the sub-module into a compact power pack.

“Through our strategic approach of incorporating scalability and modularity into our e-mobility solutions – from individual components to a highly integrated electric axle – we developed the readily integrated inverter brick. Based on our generic platform development, it took us just one year to bring this optimal product for the popular X-in-1 architectures to volume production readiness,” says Thomas Stierle, CEO of the E-Mobility Division at Schaeffler.

As a core component of an inverter, the brick has to fulfil strict demands. The characteristics of the sub-module are indicative of the factors behind the current sales success and start of volume production: ROHM’s SiC power semiconductors enable the frame-mounted sub-module with high power density to be compact, efficient, and readily integrated into various inverters through its modular and scalable design. The sub-module incorporates the power module for PWM of the current pulses, the DC link capacitor, a DC link and a cooler. Moreover, the brick features a DC boost function, allowing a vehicle with an 800V architecture to be charged at a 400V charging station at a charging speed of 800V.

“We are glad about the launch of volume production for Schaeffler’s inverter brick with our 4th generation SiC MOSFET,” says Dr Kazuhide Ino, member of the board and managing executive officer at ROHM. “With our SiC technology, we are making a substantial contribution to increasing the efficiency and performance of electric cars. Working with Schaeffler as our partner, we are thus fostering innovation and sustainability in the automotive industry,” Dr. Ino adds.

The strategic partnership between Schaeffler (originally initiated under Vitesco Technologies) and ROHM has been in place since 2020, serving to secure capacity for energy-efficient SiC power semiconductors.