High fundamental frequency conversion units for high power applications

Abstract

Wide-bandgap devices, made from materials such as silicon carbide and gallium nitride, enable the development of high fundamental frequency conversion units for high-power applications. This is due to wide-bandgap devices possessing superior material characteristics when compared to traditional silicon devices. This work examines three different silicon carbide products in a modelled 1 MW three-phase two level inverter system using PLECS. The three silicon carbide half-bridge power modules from Wolfspeed, Hitachi Energy (ABB), and Rohm are tested at switching frequencies from 10 kHz to 40 kHz. The junction temperatures as well as the conduction, switching, and total losses were observed from these simulations. Each of the devices were able to support an efficiency above 99% when switching at a frequency of 20 kHz. While the Wolfspeed and Hitachi Energy (ABB) products had better efficiencies at 10 kHz, the Rohm device outperformed them at the higher switching frequencies due to having lower switching losses. The low switching losses of the Rohm device enables the switches to safely reach switching frequencies above 40 kHz while the other products are unable to. This theoretical approach shows that silicon carbide-based wide band-gap products can safely attain high switching frequencies in high-power applications.