Implementation of an Interleaved Bidirectional CLLC Resonant Full-Bridge DC-DC Converter Based on 48-Volt Bus

Abstract

In recent years, with the rapid development of science and technology, the requirements for power electronic power supply are becoming increasingly stringent. It is more and more common to use higher voltage in the design of renewable energy and battery energy storage and release power supply. Compared with the traditional 12V power distribution, 48V distribution has lower transmission loss, which improves the efficiency. The purpose of this paper is to implement an interleaved bidirectional CLLC resonant full bridge converter for a 48V bus. The proposed topology adopts symmetrical inverter and rectifier circuit, which is more suitable for bidirectional operation. Both upper and lower bidirectional converters are connected in parallel, and the phase shift between switch closing is 90° The output voltage of the converter is regulated by pulse frequency modulation control. The converter has the following characteristics: (1) All power switches have soft switching characteristics in two-way power transmission. (2) Both reducing output current ripple and increasing output power of the converter by using interleaving technology with the output current 90° out of phase. (3) The problem of unbalanced load distribution, resulted from the difference of resonance tank parameters, is improved by using asynchronous pulse width modulation (APWM). (4) Improve the uneven current on the secondary side of the traditional LLC using APWM control.