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US 5,349,514 AGranted
Reduced-resonant-current zero-voltage-switched forward converter using saturable inductor
AssigneeOrigin Electric Company, Limited
InventorsShuichi Ushiki, Ryoji Saito
Life of this patent
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Abstract
A resonant forward converter comprises a saturable inductor connected in series to a primary winding of a transformer and a switching device. The saturable inductor has a predetermined value of inductance in a light current region and a small value of inductance at a predetermined integral voltage due to magnetic saturation.
Claims10
A zero-voltage-switched forward converter, comprising:
- a DC power supply;
- a transformer having a primary winding connected in series to said DC power supply and a secondary winding magnetically coupled with said primary winding;
- a switching device connected in series to said primary winding of said transformer;
- a first resonant capacitance connected in parallel to said switching device;
- a saturable inductor inserted in series in said primary winding of said transformer and said switching device, said saturable inductor having a predetermined value of inductance in a light current region and a small value of inductance at a predetermined integral voltage due to magnetic saturation, said saturable inductor having a non-saturated inductance which accumulates magnetic energy to discharge said first resonant capacitance up to zero voltage for zero voltage turning-on of said switching device;
- a rectifier diode connected in series to said secondary winding of said transformer;
- a free wheeling diode interposed between one end of said secondary winding of said transformer and one end of said rectifier diode;
- choke input smoothing circuit means, connected in parallel to said free wheeling diode, for smoothing current passing through said secondary winding of said transformer;
- and
- control circuit means for providing a control signal to said switching device to control a conduction thereof.
7 more elements
A zero-voltage-switched forward converter, comprising:
- a DC power supply;
- a transformer having a primary winding connected in series to said DC power supply and a secondary winding magnetically coupled with said primary winding;
- a switching device connected in series to said primary winding of said transformer;
- a resonant capacitance connected in parallel to said switching device;
- a saturable inductor connected in series to said primary winding of said transformer and said switching device, said saturable inductor having a predetermined value of inductance in a light current region and a small value of inductance at a predetermined integral voltage due to magnetic saturation, said saturable inductor including a first winding wound on a core with a rectangular hysteresis, a second winding magnetically coupled with said first winding, and a linear inductor connected in parallel to said second winding;
- a rectifier diode connected in series to said secondary winding of said transformer;
- a free wheeling diode interposed between one end of said secondary winding of said transformer and one end of said rectifier diode.
- an output filter connected in parallel to said free wheeling diode;
- and
- a control circuit means for providing a control signal to said switching device to control a conduction thereof.
7 more elements
A zero-voltage-switched forward converter, comprising:
- a DC power supply;
- a transformer having a primary winding connected in series to said DC power supply and a secondary winding magnetically coupled with said primary winding;
- a switching device connected in series to said primary winding of said transformer;
- a resonant capacitance connected in parallel to said switching device;
- a saturable inductor connected in series to said primary winding of said transformer and said switching device, said saturable inductor having a predetermined value of inductance in a light current region and a small value of inductance at a predetermined integral voltage due to magnetic saturation, said saturable inductor including a first winding wound on a core with a rectangular hysteresis, a second winding magnetically coupled with said first winding, and a third winding connected in parallel to said second winding and failing to be magnetically coupled with said first winding;
- a rectifier diode connected in series to said secondary winding of said transformer;
- a free wheeling diode interposed between one end of said secondary winding of said transformer and one end of said rectifier diode;
- an output filter connected in parallel to said free wheeling diode;
- and
- a control circuit means for providing a control signal to said switching device to control a conduction thereof.
7 more elements
Dependencies are inferred from the claim text.