Modelling of a ZVS resonant DC-DC converter for operation with freewheeling period

This study concerns an indirect DC-DC series resonant converter. The first parameter for controlling this type of converter is the operating frequency. When a phase shift β is introduced between the controls of the two legs, we get a second parameter for controlling the conversion. Using the state plane, the recurrence equation of state variables have been determined and used for computing the steady state conditions. This has allowed the curves giving the normalized output power versus the regulating parameters (frequency and phase shift) and also the steady state output characteristic to be drawn. The analysis performed includes a small signal modelling based on the linearisation of the behavior around the steady state working point