Analysis of the Operational Modes of the Phase Modulated LLC Resonant Converter

This paper presents the steady state analysis of the full bridge LLC resonant converter. Six switching stages are found due to the odd symmetry. Once the information about state variables are at hand, state plane trajectory can be constructed for each state. In this paper a detailed analysis has been presented for phase modulated LLC resonant converter to predict the resonant voltage and current waveforms of the operational modes. For these operational modes, two dimensional state plane trajectories are also observed. A design guideline has been proposed to assess which modes are practically useful and will have the highest efficiency.