Mitsubishi Electric SiC Inverter Has The Power
The silicon carbide inverter is suited to automotive and industrial applications
Mitsubishi Electric Corporation has developed a prototype forced-air-cooled three-phase 400V output inverter with all SiC power modules. The inverter has a power density of 50kVA per litre.
The inverter is expected to contribute to smaller and lighter power-electronics equipment in automotive and industrial applications, among others.
The module, which is rated at 1,200V/300A, incorporates a SiC MOSFET (metal oxide semiconductor field effect transistor) and SiC SBD (Schottky barrier diode).
To increase power density, electric current density must be increased by lower electric resistance. So Mitsubishi Electric developed low-resistance wiring by using direct lead bonding to connect power semiconductor chips directly to the main terminals, eliminating the use of conventional high-resistance aluminium lead wires.
To achieve high current density, low-loss (low-resistance) power chips also had to be used, but this required the application of high-speed protection circuits to prevent a large destructive current during short circuits.
The company applied a SiC-MOSFET with a built-in current sensor function to its all-SiC power module and used a high-speed short-circuit-protection circuit, making it possible to use a low-resistance SiC-MOSFET even at a high current density.
By doing this, the company successfully achieved a power density of 50kVA per litre by an inverter operation with an output of 156kVA.
While silicon has traditionally been used for power semiconductor devices, in recent years SiC has come to be widely considered as one of the most promising next-generation materials. It has a breakdown electric field that is about 10 times higher than silicon and reduces power loss, meaning there is less CO2 emission.
What's more, the amount of cooling equipment in applications can be reduced, making the overall downsizing and lightening of electronic components for auto