Steady state analysis of the phase-controlled LCC-type series-parallel resonant converter operating above resonance

This paper presents a new analysis providing further insight into the steady state characteristics of the phase-controlled LCC-type series-parallel resonant converter operating above resonance. An analytical expression is obtained for the converter voltage transfer function in terms of phase angle. The effect of varying the phase angle on ZVS and ZCS of the inverter switches is studied and, accordingly, converter modes of operation are classified and illustrated. Mode boundaries are analytically derived and graphically represented to ease the determination of converter operating mode at any loading, frequency and phase angle combination. Finally, maximum power transfer criterion is obtained and plotted for the converter. The analysis presented is helpful with converter design and determination of the suitable operating conditions.