A Current-Fed Dual-Half-Bridge-Based Composite Converter With Improved Light-Load Efficiency Through a Multi-Variable Optimization

• Published in: IEEE transactions on transportation electrification Vol. 8; no. 2; pp. 3008 - 3020
• Main Authors: Lin, Nan, Zhao, Zhe, Diao, Fei, Zhao, Yue, Balda, Juan Carlos
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01-06-2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Composite converter; Conversion ratio; Converters; current-fed dual-half-bridge (CF-DHB); Efficiency; efficiency improvement; Electric bridges; Electric vehicles; Electronic devices; Hybrid electric vehicles; Inductors; light load; Modules; multi-variable optimization; Optimization; Silicon carbide; Stress; Switches; Topology; Voltage; Zero voltage switching
• ISSN: 2332-7782; 2577-4212; 2332-7782
• DOI: 10.1109/TTE.2021.3126726

Due to its frequent occurrence in the electric vehicle (EV) and hybrid electric vehicle (HEV) applications, light-load efficiency of the dc-dc converter is critical. Different from the conventional boost converter, in this work, a novel composite converter is proposed and investigated to achieve significantly improved light-load efficiency. The proposed converter consists of a current-fed dual-half-bridge (CF-DHB) converter module and a boost converter module, which can be controlled and optimized independently. The interconnection of the two modules leads to advantages, such as lower voltage stress across the power device and a wide conversion ratio. In this article, a multi-variable efficiency optimization method is proposed utilizing the topology advantages of the proposed converter to address the light-load efficiency issue. Based on the loss model, the power sharing between the two converter modules and the switching frequency of the boost converter module are optimized at light load. A 30-kW silicon carbide (SiC)-based composite dc-dc converter prototype is built to validate the proposed multi-variable efficiency optimization method in the light-load operating conditions. Extensive experimental results are presented to demonstrate the noticeable efficiency improvement brought by the proposed method.