Optimal design method for series LCLC resonant converter based on analytical solutions for voltage gain resonant peaks

Series LCLC resonant tank (SS topology), LLC resonant tank, and series-parallel LCLC resonant tank (SP topology) are commonly used for wireless power transfer applications. However, conventional resonant tank design methods are exceedingly tedious and/or complex and are mostly based on a trial-and-error approach. This is due to the complexity in resonant characteristics of the SS topology. As a result, in the literature no design method has been proposed that allows rapid calculation of resonant tank parameters. In this paper, such a design method is introduced: a rapid parameter calculation method for designing the SS topology having identical magnetic core geometry on primary and secondary sides with arbitrary turns ratio. Deriving the proposed design equations requires determining various resonant frequencies of interest of the SS topology. Interpretation of the meaning of these frequencies and discussion of their importance for resonant tank design are included. Also, it is shown that some of these frequencies have important roles for the LLC and SP topologies as well. The accuracy of proposed design equations is evaluated in both simulation and experiment.