On the utilisation of the transformer parasitic capacitances as a resonant component in high voltage converters operating above resonance with variable frequency

The authors present a variable frequency resonant converter with an output inductor filter operating above resonance where the resonant circuit is constituted only of the transformer leakage inductance and the secondary parasitic capacitance referred to the primary side. First, they present the HV transformer equivalent circuit which is simplified and integrated in a series-parallel resonant converter. In the second place, the limits imposed by the behaviour of the transformer at high frequencies are discussed and included in the converter operation characteristics. Experimental validations are presented