Soft switching DC-to-DC converter with coupled inductors

摘要

A DC-to-DC converter topology is provided having switching devices that are switched under zero voltage switching conditions to minimize switching losses. The converter of the present invention includes two input side converter bridges, each based on a two switch forward converter topology. The input side converter bridges may be connected in series for high input voltage levels and in parallel for low voltage levels. The switching devices of each input side converter bridge are coupled together by coupling inductors. The turning-off of a switching device in one bridge causes part of the energy stored in the corresponding coupled inductor to discharge an output capacitance of an incoming switching device in the other bridge, causing an anti-parallel connected diode to conduct. The incoming switch can thus be turned on under zero voltage switching conditions. Zero voltage switching can be achieved over a wide load range by properly sizing the coupled inductors. The converter switching devices are preferably provided switching signals from a peak current control controller that controls the duty cycle of the converter to regulate the peak of the output currents to control the output power delivered to a load.