Rohm has revealed that it is developing 1.2kV 400A/600A rated full SiC power modules (BSM600D12P3G001, BSM400D12P3G002) that target inverters and converters in solar power conditioners, UPS and power supplies for industrial equipments.

The BSM600D12P3G001 achieves a rated current of 600A by utilising a new package featuring an original internal structure and optimised heat radiation design, enabling support for higher power applications such as large-scale power supplies for industrial equipment. According to Rohm, switching loss is reduced by 64% (at a chip temperature of 150°C) compared with IGBT modules at the same rated current, improving energy savings considerably.

And along with reducing the size of peripheral components through high-frequency operation, the effects of reducing switching loss are greater when driving at high frequencies, contributing to the miniaturisation of cooling and other systems. For example, from preliminary calculations based on loss simulation in cooling systems, adopting SiC modules can reduce the size of water-cooled heat sinks by up to 88% compared with equivalently rated IGBT modules.

Suppressing effects of surge voltage

To maximise the high-speed switching characteristics of SiC, particularly in products with large current ratings such as power modules, it is necessary to develop a new package that suppresses the effects of surge voltage during switching. These Rohm modules utilise a new package design that expands the company's SiC module lineup to cover the key current range from 100A to 600A to meet the growing demand in the IGBT market.

Increasing the current rating of power modules also increases the surge voltage during switching, making it necessary to minimise inductance within the package. However, optimising the internal placement of the SiC device along with terminal configuration and pattern layout allows Rohm to reduce internal inductance by 23% vs conventional products, the company noted. Rohm's new G Type package suppresses surge voltage by 27% at the same loss compared with standard packages, enabling the development of 400A and 600A modules. This new package decreases switching loss by 24% under the same surge voltage drive conditions, Rohm said.

Achieving a rated current of 600A entails not only reducing internal inductance but heat generation as well. By improving the flatness of the base plate section that significantly contributes to the heat dissipation of the module, Rohm claims it was able to decrease the thermal resistance between the cooling mechanism and the customer's base plate by 57%.

Samples and OEM quantities will be available on June 2017.