Large-signal transient analysis of forward converter withactive-clamp reset

摘要

The forward converter with the active-clamp reset offers manynadvantages over the forward converters with other transformer-resetnmethods. However, during the line and load transients, the maximumnmagnetizing current of the transformer and the peak voltage of thenprimary switch are strongly affected by the active-clamp circuitndynamics. As a result, the design of a forward converter with thenactive-clamp reset cannot be optimized based only on its DCncharacteristics. Due to the nonlinearity of the circuit, it is veryndifficult to derive the closed-form equations for the transient responsenof the active-clamp circuit. In this paper, an average-state-trajectorynapproach is proposed to analyze the transient behavior so that thentrends of the maximum magnetizing current of the transformer and thenpeak voltage of the primary switch can be easily predicted undernworst-case conditions and parameter variations