Phase-Shift Modulated Hybrid <i>SCLLC</i> Topology at Fixed-Frequency for Wide Voltage Range Without Extra Components

In the application of an intermediate bus converter, the traditional frequency-modulated <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> suffers from low regulation efficiency, bulky magnetic components, and high electromagnetic interference (EMI). In this work, a hybrid <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SCLLC</i> topology is proposed by integrating a switched-capacitor (SC) converter with the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter. Thanks to the additional power delivery path provided by SC, partial power can be delivered directly to the load without passing through the transformer, thereby improving efficiency. In the proposed integrated topology, the stacked bridge and resonant tank in the SC and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> are multiplexed without adding any components. Besides, a fixed-frequency phase-shift modulation strategy is employed for voltage regulation, which is beneficial to reduce the size of the magnetic components and limit EMI. Moreover, zero-voltage switching is well-realized for all primary switches in a wide range. Finally, an experimental prototype with a 40–60 V input and 12 V/200 W output demonstrates a peak efficiency of 97.5%, validating the proposed topology. At 60 V input, owing to the higher SC power ratio, the system achieves an efficiency over 95% across the full load range (2 A–16 A).