Considerations on the relationship between distributed capacitance and iron loss in high-voltage transformers

This paper describes the results of an analysis on the relationship between distributed capacitance and iron loss in a high-voltage transformer applied to a push-pull current-fed converter in a high-voltage power supply. There are two operating modes in a push-pull current-fed converter; a boost mode and buck mode. In both modes, the maximum amplitude of magnetic flux density in the transformer decreases with increasing distributed capacitance. The reason for this is that the product of the transformer voltage and time decreases as the capacitance increases. Consequently, when distributed capacitance exists in a transformer, the transformer temperature rise due to iron loss is smaller than that in transformers without distributed capacitance. This indicates that the transformer temperature rise due to iron loss, which varies along with the distributed capacitance, needs not be taken into consideration in transformer thermal design even if the distributed capacitance increases in a high-voltage transformer.