New SiC MOSFETs enhance efficiency in challenging applications

Toshiba Electronics Europe GmbH has developed a new 2200V rated SiC MOSFET with embedded SBD for use in 1500VDC applications such as PV inverters, EV chargers, high-frequency DC-DC converters and energy storage systems. The new device simplifies inverter designs and increases power density, decreasing size and weight.

Conventional three-level inverters display low switching losses as the off-state voltage across switching devices is half the line voltage. In comparison, two-level inverters offer fewer switching modules, making them simpler, smaller, and lighter. However, they need semiconductor devices with higher breakdown voltage, as the applied voltage is the line voltage. Fulfilling this challenge is essential as a two-level inverter based upon the new device accomplished higher frequency operation and lower power loss than a conventional three-level Si IGBT inverter.

The new dual SiC MOSFET module (MG250YD2YMS3) provides a VDSS rating of 2200V and can support a continuous drain current (ID) of 250A, with 500A in pulsed operation (IDP). Isolation (Visol) is rated at 4000Vrms, and the device can function at channel temperatures (Tch) as high as 150C.

It provides low conduction loss with a typical drain-source on-voltage (VDS(on)sense) of 0.7V. Switching losses are minimised with typical turn-on and turn-off losses of 14mJ and 11mJ, respectively, meaning that the necessity for thermal management is less, resulting in smaller inverters.

Within the module, the impurity concentration and thickness of the drift layer have been optimised to keep the same relationship between the on-resistance (RDS(ON)) and the breakdown voltage as existing products. This also strengthens immunity to cosmic rays, a key necessity for PV systems. Also, embedding SBDs with clamped parasitic PN junctions between the p-base regions and the n-drift layer provides reliability in reverse conduction conditions.

Switching energy loss for the developed all-SiC module is much lower than equivalent silicon modules. In comparison, the new SiC module attains double the frequency of a conventional Si IGBT and 37% lower loss when comparing a two-level SiC inverter against a three-level Si inverter.