A Complete Step-by-Step Optimal Design for <i>LLC</i> Resonant Converter

Abstract

LLC resonant converters have been widely used in many different industrial applications. Analysis and design methodologies have great effect on the converter performance. Accordingly, a complete step-by-step optimal design methodology based on time-domain analysis has been proposed for an LLC resonant converter in this article. The proposed design methodology is implemented under the worst operation condition, and the following considerations are included to obtain the suitable design area: operation mode; voltage stress for resonant capacitor; zero voltage switching operation for primary switches; and resonant tank root-mean-square current. Then, by finding all possible design candidates and comparing them based on the power loss model, the optimized design candidate can be found. Compared with the existing design methodologies, the proposed one has the advantages of high accuracy and small computation requirement, which makes it application in industry possible. Finally, a 192-W experimental prototype was built to validate the effectiveness of the proposed design methodology. In addition, a MATLAB graphical user interference program was built based on the proposed design methodology to visualize and facilitate the design process for engineers.