A Novel Wide Gain Range LLC Resonant Converter With Multiple Operating Modes

Abstract This paper proposes a novel LLC resonant converter featuring two completely identical resonant circuits. By adjusting the control strategy of primary‐side switches, the two resonant circuits can operate independently or in series, allowing the entire resonant converter to function equivalently in half‐bridge or full‐bridge LLC resonant converters. The proposed converter exhibits three distinct operating modes, and all modes maintain identical resonant frequency while achieving a wide output voltage regulation range (0.5 to 4 times) within a narrow frequency variation range (70 to 130 kHz). Furthermore, zero voltage switching (ZVS) of primary side switches is consistently ensured across all operating modes. Compared with the conventional LLC resonant converter, the proposed topology extends the output voltage regulation range without requiring additional switches or complex control strategies. Experimental results validate the effectiveness and practicality of the proposed converter, demonstrating an operational efficiency of no less than 96% across various operating modes.