A "Predictive" Synchronous Rectifier Control for High-Frequency Series Resonant Converters

A predictive synchronous rectifier (SR) sensing and control method is proposed in this paper using a Rogowski coil with a passive integrator and an adaptive SR turn-off scheme in order to optimize series resonant (SRes) converter efficiency. Unlike other SR sensing methods used in SRes converters, the SR sensing method proposed here has high bandwidth, can be operated at high operational frequency and doesn’t have SR voltage level limitations. Therefore, this method is suitable for optimizing the efficiency of a high-frequency, high-power-density SRes converter. This paper discusses the operation principles and experimental results of the method on a 6.6-kW capacitor-inductor-inductor-inductor-capacitor (CLLLC) series resonant dual active bridge converter.