Achieving ZVS in a two quadrant converter using a simplified auxiliary circuit with novel control

This paper proposes a new soft-switching scheme as well as a novel control approach for a two quadrant converter. The auxiliary engine utilizes a simple architecture consisting of pair of switches, an inductor and several diodes to provide the necessary characteristic. We propose a simple two-quadrant current feedback scheme that adjusts the auxiliary switch on-times appropriately to minimize conduction losses, thus achieving ZVS in both quadrants from maximum negative to maximum positive load. Dead-time is fixed but conduction time of the auxiliary switches occurring within the dead-time is variable with load. A brief survey of various conventional techniques is also presented. PSIM simulations for the proposed model as well as a unique MathCAD analysis of the various states along with empirical data are provided.