NEWS & EVENTS
Sic-based high frequency soft-switching three-phase converters for grid-tie applications
Feb 08, 2017
Three-phase AC/DC converters are widely used in grid-tie applications, such as PV inverter systems, charging stations and data centers. However, power density is limited by using Si devices and operating at tens of kHz switching frequency. In order to improve the power density of the grid-tie three-phase converter, SiC MOSFET is used and the converter is operating at hundreds of kHz switching frequency. Soft switching is the key factor to maintain high efficiency with significantly increased switching frequency. Critical conduction mode (CRM) is the simplest way to achieve soft switching without adding physical complexity to the converter. However very limited modulation methods can be found in literature for CRM three-phase converter. Therefore in this presentation, a new modulation method is proposed for the three-phase converter which combines CRM and discontinued pulse width modulation (DPWM) to achieve soft switching and minimized switching loss. The proposed modulation is verified by simulation. Efficiency estimation and loss analysis are also provided.
