Abstract:

To address output-current imbalance in a two-phase interleaved parallel LLC resonant converter,a phase-shift-based current-sharing strategy is proposed.Firstly,an analytical expression of the voltage gain under phase-shift modulation is derived,theoretically confirming the feasibility of achieving current sharing.Secondly,to reduce the volume of magnetic components and improve power density,an integrated magnetics design is developed for the converter.Finally,a 1 kW/48 V prototype is built and comparative experiments are conducted between discrete magnetics and integrated magnetics implementations.Experimental results demonstrate that the proposed phase-shift current-sharing control together with the integrated magnetics scheme can limit the current imbalance between the two phases to within 5%.Compared with the discrete magnetics solution,the magnetic-component volume is reduced by 7.1% and the converter efficiency is improved by 0.7%,validating the rationality and feasibility of the theoretical analysis and design.

Key words: interleaved parallel LLC, phase-shift control, magnetic components, integrated magnetics