Modeling and Analysis of a High-Voltage DC-DC Converter with Vin/3-Voltage Stress on the Primary´s Switches

The modeling, design, and analysis of a previously developed high-voltage dc-dc converter is presented in this paper. The key feature of this converter is that the voltage stress on the switches in the converter is only one-third of the input voltage. Moreover, all switches in the converter are zero-voltage-switched and the output circuit is a current tripler, so that the output current capacity and the power capacity of the converter are increased. In this paper, the relationship between the zero voltage switching (ZVS) condition and the load current will be formulated. A detailed dc analysis will be carried out to calculate the effective duty-cycle. Small-signal ac models of the power stage including the control-to-output and input-to-output transfer functions will also be derived. A 4.8kW, 1000V/48V dc-dc converter prototype has been built and tested for confirming the theoretical predictions.