An Improved Cascading Scheme to Achieve Wide Gain Range and Efficiency Optimization for Resonant Forward Converter

This article presents an improved cascading scheme for the resonant forward converter to widen the gain range while reducing losses and complexity by removing two filtering components. The efficiency is optimized for the second stage through the phase-shift-controlled current injection directly from the first stage. Then, the improvement is achieved by adaptively adjusting the resonant duration according to the voltage-stress-control determined
on
-time, and thus, the root-mean-square values of current in transformer windings are reduced. Based on the detailed analysis and design considerations, the experimental results validate the effectiveness of the proposed scheme.