Direct power AC/DC converter

An apparatus, comprising:

• a transformer comprising a first primary winding magnetically coupled to a secondary winding;
• a first series resonant impedance comprising a first resonant inductor, a first resonant capacitor, and the first primary winding connected in series;
• a first switching network connected between a first AC power node and a second AC power node, the first switching network comprising a first bi-directional switch connected in series with a second bi-directional switch, wherein the first series resonant impedance is connected in parallel with the second bi-directional switch;
• a rectifier switch connected between a first end of the secondary winding and a first DC node;
• and a bus capacitor connected in parallel with a second switching network, wherein a second end of the secondary winding is connected to a second DC node, and wherein the first bi-directional switch comprises a first switching device connected in series with a second switching device wherein a source of the first switching device is connected to a source of the second switching device, and wherein the second bi-directional switch comprises a third switching device connected in series with a fourth switching device wherein a source of the third switching device is connected to a source of the fourth switching device, and wherein a predetermined voltage threshold to activate the first switching network is greater than a DC output voltage times the turn ratio between the first primary winding and the secondary winding.

An apparatus, comprising:

• a transformer comprising a first primary winding magnetically coupled to a secondary winding;
• a first series resonant impedance comprising a first resonant inductor, a first resonant capacitor, and the first primary winding connected in series;
• a first switching network connected between a first AC power node and a second AC power node, the first switching network comprising a first bi-directional switch connected in series with a second bi-directional switch, wherein the first series resonant impedance is connected in parallel with the second bi-directional switch;
• and
• a rectifier switch connected between a first end of the secondary winding and a first DC node,
• an AC voltage connected across the first AC power node and the second AC power node,
• wherein a second end of the secondary winding is connected to a second DC node, and
• wherein the first bi-directional switch comprises a first switching device connected in series with a second switching device wherein a source of the first switching device is connected to a source of the second switching device,
• wherein the second bi-directional switch comprises a third switching device connected in series with a fourth switching device wherein a source of the third switching device is connected to a source of the fourth switching device,
• wherein, when a magnitude of the AC voltage is greater than a predetermined voltage threshold, a fifth switching device and a sixth switching device are turned off and the first bidirectional switch and the second bidirectional switch are operated to transfer power from the AC voltage to the first DC node and the second DC node, and
• when the magnitude of the AC voltage is not greater than the predetermined voltage threshold, the first bidirectional switch and the second bidirectional switch are turned off, and the fifth switching device and the sixth switching device are operated to transfer power from the AC voltage to the first DC node and the second DC node.