The thesis focuses on design and analysis techniques (rather than on feedback control techniques) oriented towards LLC resonant power converters with the objective of improving the state-of-the-art and better understanding advantages and limitations. Then, a different design approach based on the exact analysis of the converter evolution and capable of taking into account the effect of parasitic resistances at both the primary and secondary side of the transformer is proposed. In particular, the sequence of on-off states of all switching devices characterising the operation at resonance (in CCM) is extracted; this allows to solve step-wise the differential equations describing circuital evolution of the converter (including lossy elements, not considered in any of the known design approach in the state-of-the-art) in the MATLAB environment.