A Comparative Analysis of Half-Bridge LLC Resonant Converters Using Si and SiC MOSFETs

With the expansion of renewable energy sources worldwide, the need for developing more economical and more efficient converters that can operate on a high frequency with minimal switching and conduction losses has been increased. In power electronic converters, achieving high efficiency is one of the most challenging targets to achieve. The utilization of wideband switches can achieve this goal but add additional cost to the system. LLC resonant converters are widely used in different applications of renewable energy systems, i.e., PV, wind, hydro and geothermal, etc. This type of converter has more benefits than the other converters such as high electrical isolation, high power density, low EMI, and high efficiency. In this paper, a comparison between silicon carbide (SiC) MOSFET and silicon (Si) MOSFET switches was made, by considering a 3KW half-bridge LLC converter with a wide range of input voltage. The switching losses and conduction losses were analyzed through mathematical calculations, and their authenticity was validated with the help of software simulations in PSIM. The results show that silicon carbide (SiC) MOSFETs can work more efficiently, as compared with silicon (Si) MOSFETs in high-frequency power applications. However, in low-voltage and low-power applications, Si MOSFETs are still preferable due to their low-cost advantage.