Research on Synchronous Rectifier Digital Control Method of LLC Converter

Abstract

Synchronous rectification is an effective method to improve efficiency and reduce loss of LLC resonant converter. In this paper, without introducing any auxiliary detection devices, a mathematical model is established to theoretically calculate the turn-on and turn-off times of the primary side and secondary side MOS in different working regions, and according to the delay and dead zone transient requirements in the hardware circuit The digital algorithm is used in the DSP processor for real-time control of synchronous rectification, which significantly reduces the design complexity of synchronous rectification control and improves the flexibility of control. And the effectiveness of the synchronous rectification control strategy is verified by 12V/125A1.5kW LLC simulation and experiment.