Unified design for ZVT PWM converters with resonant auxiliary circuit

Operation modes of zero-voltage transition (ZVT) PWM converters with resonant auxiliary circuit (RAC) are identified and analysed by means of a common topology. A novel state-plane approach is used to determine the soft-switching boundary for this sort of converter. A unified design criterion, based on the analytical definition of the soft-switching boundary, is described in detail. By means of the proposed criterion the time spent on repetitive numerical simulation of a given topology to define its design guidelines based on a set of particular features can be significantly reduced. The theoretical analysis is confirmed by means of experimental results obtained from ZVT-PWM boost converters, which operate at 1 kW, 100 kHz.