A Modified LLC-AHB Converter to Achieve Wide Voltage Gain

In this paper, a modified LLC-asymmetric half bridge flyback converter (AHB) that can realize a wide range of voltage gain is proposed. This type of topology utilizes the idea of topology morphing to realize the mode transition between LLC mode and AHB mode by adding bidirectional switches. The optimal design of resonant tank is realized while avoiding the extra resonant inductor of LLC mode, which solves the problem of conventional LLC-AHB converter that the efficiency of LLC mode decreases due to the small LLC magnetizing inductor and the over-resonance due to the small <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{L}_{\mathbf{n}}$</tex> (ratio of magnetizing inductance to resonant inductance). The considerations, optimal design of this topology are discussed in this paper. Finally, the performance of the proposed topology is confirmed by simulation results.