4th China International Youth Conference on Electrical Engineering (CIYCEE 2023)

Abstract -- This paper presents a proposed three-level bidirectional CLLLC topology and analyzes its operating mode and gain characteristics. This topology operates in a three-level mode, significantly reducing the harmonic component of the input voltage. Consequently, it enhances the accuracy of the widely used fundamental harmonic approximation (FHA) analysis method in engineering, improves the efficiency of the bidirectional CLLLC converter, and expands its working range. Additionally, this paper proposes a three-level bidirectional CLLLC synchronous rectification strategy to accurately track the turn-on time of the synchronous rectifier with respect to the actual current flow time. As a result, the operational efficiency of the converter can be further enhanced. The feasibility of the proposed topology was verified using Matlab/Simulink. Furthermore, an experimental prototype was developed based on the proposed design scheme to validate the benefits of the multilevel CLLLC topology and its control scheme presented in this paper.

bi-directional CLLLC converter,multilevel,FHA,synchronous rectification