Patent ID: 8040704
Filing Date: 2011-10-18
Classification: H02M,Y02B

Abstract:
1. An isolated lossless switching DC-to-DC converter for providing power from a DC voltage source connected between an input terminal and a common input terminal to a DC load connected between an output terminal and a common output terminal, said converter comprising: an isolation transformer with primary and secondary windings, and first and second output inductors' windings, placed on a two-loop magnetic cores structure to form an Integrated Magnetics, and each winding having one dot-marked end and another unmarked end whereby any AC voltage applied to said primary winding of said isolation transformer induces AC voltages in said secondary winding of said isolation transformer and said first and second output inductor windings so that all four AC voltages are in phase at dot-marked ends of said first output inductor winding, said second output inductor winding and said primary and secondary windings of said isolation transformer; said first output inductor winding connected at a dot-marked end thereof to said secondary winding of said isolation transformer at a dot-marked end thereof, and connected at an unmarked end thereof to said output terminal; said second output inductor winding connected at a dot-marked end thereof to said output terminal, and connected at an unmarked end thereof to said secondary winding of said isolation transformer at an unmarked end thereof; said primary winding of said isolation transformer connected at an unmarked end thereof to said common input terminal; an input switch with one end connected to said input terminal and another end connected to said dot-marked end of said primary winding of said isolation transformer; a branch comprised of a complementary input switch and an auxiliary capacitor connected in series, wherein one end of said branch is connected to said dot-marked end of said primary winding of said isolation transformer and another end of said branch is connected to said unmarked end of said primary winding of said isolation transformer; an output switch with one end connected to said common output terminal and another end connected to said unmarked end of said secondary winding of said isolation transformer; a complementary output switch with one end connected to said common output terminal and another end connected to said dot-marked end of said secondary winding of said isolation transformer; switching means for keeping said input switch ON for a duration of time interval DT whereby large circulating current in said secondary transformer winding and said first and said second output inductors windings is eliminated within full range of said operating duty ratio D, and whereby ripple currents in said first and said second output inductors windings and rms current in said secondary transformer winding are substantially reduced at any operating duty ratio D.