Application-Oriented Review of the LLC-Based Resonant Converters

The LLC resonant converter is a widely utilized power electronics converter, due to its numerous industrial and domestic applications. This converter offers some advantages such as soft-switching operation of all switches, high efficiency, high power density, low voltage stress, minimal electromagnetic interference (EMI) noise, input/output isolation, wide input/output voltage range, and reliable and good performance under the wide load variation ranges, as well as good light-load operation. However, this converter has certain limitations, which can be addressed to enhance its operation and efficiency. This paper provides an in-depth review and comparison of various LLC-based resonant converter configurations, focusing on their operational principles, mathematical analysis, control methods, and some practical applications including electric vehicle chargers, TV power supplies, LED drivers, photovoltaic cells, HVDC production, fuel cells, and wireless power transfer applications. By examining the strengths and weaknesses of the different LLC resonant converter designs, this study aims to contribute to the ongoing research efforts in improving the performance and efficiency of this important power electronics converter.