Design Criteria for Transformers in High Voltage Output, High Frequency Power Converter Applications

Abstract

SummaryWhen a dc high voltage needs to be obtained from low voltage inputs (main voltage), the necessary power converter needs a high value for its transformation ratio; consequently, a large number of turns is often necessary for secondary windings and some parasitics appear (large leakage inductance and large capacitance). Thus, it is usual to design a resonant converter to include both inductance and capacitance in the power topology. However, as the parasitics are used to obtain the resonance, their value (and their spreads) are critical. The present paper proposes several criteria in order to establish an adequate method for constructing the transformer, and a new topology for transformers and a model for parasitic capacitances are also presented taking into account high voltage and high frequency problems and limitations of materials.