ZVT PWM converters with magnetically coupled auxiliary voltage source: a unified comparative theoretical-experimental analysis

This paper proposes a generalized circuit diagram for ZVT PWM converters with magnetically coupled auxiliary voltage source. This generalized circuit is analyzed, its operation modes are derived and the general operation constraints are defined. By means of this general topology, published ZVT PWIM converters with magnetically coupled auxiliary voltage source can be systematized and better evaluated. Based on the approach presented, the turns ratio N is determined for each topology analyzed, guaranteeing a more realistic soft-switching boundary. In addition, a comparative analysis is presented of the volume of the magnetic ferrite cores and of the current ratings through the transformer windings. A comparative analysis of efficiency is presented together with experimental results, obtained from 1 kW - 100 kHz laboratory prototypes, which confirm the value of the proposal and theoretical analysis.