Power Conversion with Current Sensing Coupled through Saturating Element

A current-modulating power converter comprising:

• a link reactance which includes an inductor and a capacitor in parallel;
• multiple switches operable to connect said inductor of said link reactance, with reversible polarity, to any selected one of multiple external connections;
• and
• control circuitry, connected through a saturable sense inductor to sense zero-crossings of current through said inductor of said link reactance;
• wherein said sense inductor is small enough to remain in saturation during more than 95% of the time, when the converter is operating at full power;
• and wherein said control circuitry controls operation of said switches in at least partial dependence on the output of said saturable sense inductor.

A method for power conversion, comprising:

• driving power, from at least one input connection, into a link inductor, to thereby flow current through said link inductor in a first direction with increasing magnitude;
• extracting power, from said link inductor to at least one output connection, while continuing the flow of current through said link inductor in said first direction, with decreasing magnitude;
• monitoring current flow through said link inductor using a saturable sense inductor, which saturates more than ten times as quickly as said link inductor;
• and
• when sense wire on said sense inductor provides a pulse showing that current on said link inductor has passed through zero, then driving power, from at least one input connection, into said link inductor, to thereby flow current through said link inductor in a second direction with increasing magnitude;
• and thereafter
• extracting power, from said link inductor to at least one output connection, while continuing the flow of current through said link inductor in said second direction, with decreasing magnitude.