Research on High Efficiency Hybrid Control Scheme of CLLC Resonant Converter

Bidirectional CLLC resonant converters have the characteristics of high frequency and high efficiency, and are widely used in new energy systems and electric vehicles, followed by the generation of various control strategies. In this paper, a detailed loss comparison analysis of various control strategies is carried out, and the advantages of each control strategy are synthesized, and a new hybrid control method combined with pulse frequency modulation (PFM), primary side pulse phase shift modulation (PSPSM) and secondary side pulse width modulation (SSPWM) is obtained. The hybrid control strategy realizes zero voltage turn-on of all MOSFETs, thereby achieving high efficiency over a wide load range and voltage gain range, and the soft conversion between three control strategies is introduced. Finally, a prototype with a high-voltage side of 400V, a low-voltage side of 40-60V, and a rated power of 500W is built. The experimental results verified the superiority of the hybrid control.