DC converter with improved power factor

Claim 2

The DC converter as defined in Claim 1, wherein a rectifying element is connected in series with the secondary winding of the choke coil.

Claim 3

The DC converter as defined in Claim 2, wherein another rectifying element is connected between a joint portion of the secondary winding of the choke coil and the rectifying element and a joint portion of the rectifying circuit and the smoothing capacitor.

Claim 4

The DC converter as defined in Claim 2, wherein a second rectifying element is connected between a joint portion of the rectifying element and the smoothing capacitor and a joint portion of the rectifying circuit and the secondary winding of the choke coil.

Claim 5

The DC converter as defined in Claim 3, wherein a capacitor connected between a joint portion of the rectifying circuit and the secondary winding of the choke coil and a joint portion of the rectifying circuit and the second rectifying element.

Claim 6

In a DC converter including a rectifying circuit connected with an AC power source; a smoothing capacitor connected with the output terminals of the rectifying circuit; a transformer having primary and secondary windings; and a series circuit which contains the primary winding of the transformer and a switching element, said series circuit being connected with both ends of the smoothing capacitor to generate DC output from the secondary winding of the transformer through a rectifier smoothing circuit by on and off operation of the switching element turn, the improvement comprising: a choke coil having primary and secondary windings; and a capacitor connected in series with the primary winding of the choke coil; the primary winding of the choke coil and the capacitor being connected in parallel with the primary winding of the transformer; and the secondary winding of the choke coil being connected between the rectifying circuit and the smoothing capacitor.

Claim 7

The DC converter as defined in Claim 6, wherein a rectifying element is connected in series with the secondary winding of the choke coil.

Claim 8

In a DC converter including a rectifying circuit connected with an AC power source; a smoothing capacitor connected with the output terminals of the rectifying circuit; a transformer having primary and secondary windings; and a series circuit which contains the primary winding of the transformer and a switching element, said series circuit being connected with both ends of the smoothing capacitor to generate DC output from the secondary winding of the transformer through a rectifier smoothing circuit by on and off operation of the switching element turn on and off, the improvement comprising: a choke coil having primary and secondary windings; and a rectifying element connected in series with the primary winding of the choke coil; said primary winding of the choke coil and rectifying element being connected in parallel with the primary winding of the transformer; and the secondary winding of the choke coil is connected between the rectifying circuit and the smoothing capacitor.

Claim 9

The DC converter as defined in Claim 8, wherein a second rectifying element is connected in series with the secondary winding of the choke coil.

Claim 10

In a DC converter including a rectifying circuit connected with an AC power source; a smoothing capacitor connected with the output terminals of the rectifying circuit; a transformer having primary and secondary windings; and a series circuit which contains the primary winding of the transformer and a switching element, said series circuit being connected with both ends of the smoothing capacitor to generate DC output from the secondary winding of the transformer through a rectifier smoothing circuit by on and off operation of the switching element, the improvement comprising: a choke coil having primary and secondary windings; the primary winding of the choke coil being connected in series between the secondary winding of the choke coil and the rectifier smoothing circuit; and the secondary winding of the choke coil being connected between the rectifying circuit and the smoothing capacitor.

Claim 11

The DC converter as defined in Claim 10, wherein a rectifying element is connected in series with the secondary winding of the choke coil.

Claim 12

In a DC converter including a rectifying circuit connected with an AC power source; a series circuit which contains primary and second smoothing capacitors, connected with the output terminals of the rectifying circuit; a change means connected between a joint portion in the series circuit where the primary and second smoothing capacitors are connected with each other and one end of the AC power source; a transformer having a plurality of windings; and the primary winding of the transformer and a switching element which are connected in series with both ends of the series circuit of the primary and second smoothing capacitors for taking DC output from the secondary winding of the transformer via a rectifier smoothing circuit by making the switching element turn on and off, the improvement comprising: a choke coil having primary - tertiary windings; and the primary winding of the choke coil being connected in series in a series circuit of the primary winding of the choke coil and the switching element; the secondary winding of the choke coil being connected between one of the output terminals of the rectifying circuit and the first smoothing capacitor; and the tertiary winding of the choke coil is connected between the other one of the output terminals of the rectifying circuit and the second smoothing capacitor.

Claim 13

The DC converter as defined in Claim 12, wherein a first rectifying element is connected in series with the secondary winding of the choke coil; and a second rectifying element is connected in series with the tertiary winding of the choke coil.

Claim 14

The DC converter as defined in Claim 13, wherein a third rectifying element is connected between a joint portion of the secondary winding of the choke coil and the first rectifying element and a joint portion of the first and second smoothing capacitors, and a fourth rectifying element connected between a joint portion of the first and second smoothing capacitors and a joint portion of the tertiary winding of the choke coil and the second rectifying element.

Claim 15

The DC converter as defined in Claim 14, wherein a capacitor is connected between a joint portion of the rectifying circuit and the secondary winding of the choke coil and a joint portion of the rectifying circuit and the tertiary winding of the choke coil.

Claim 16

The DC converter as defined in Claim 14, wherein a first capacitor is connected between a joint portion of the rectifying circuit and the secondary winding of the choke coil and the change means; and a second capacitor is connected between the change means and a joint portion of the rectifying circuit and the tertiary winding of the choke coil.

Claim 17

In a DC converter including a rectifying circuit connected with an AC power source; a smoothing capacitor connected with the output terminals of the rectifying circuit; a first series circuit which contains first and second switching elements, said first series circuit being connected with both ends of the smoothing capacitor; a second series circuit which contains first and second half-bridge capacitors, said second series circuit being connected in parallel with the first series circuit; a transformer having primary and secondary windings; the primary winding of the transformer being connected between a joint portion in the series circuit of the first and second switching elements and a joint portion of the first and second half-bridge capacitors to generate DC output from the secondary winding of the transformer through a rectifier smoothing circuit by on and off operation of the first and second switching elements, the improvement comprising: first and second choke coils having primary and secondary windings respectively; and the primary winding of the first choke coil being connected in series with the first switching element; the primary winding of the second choke coil being connected in series with the second switching element; the secondary winding of the first choke coil being connected between the rectifying circuit and the smoothing capacitor; and the secondary winding of the second choke coil being connected in parallel with the secondary winding of the first choke coil.

Claim 18

The DC converter as defined in Claim 17, wherein a first rectifying element is connected in series with the secondary winding of the first choke coil; and a second rectifying element is connected in series with the secondary winding of the second choke coil.

Claim 19

In a DC converter including a rectifying circuit connected with an AC power source; a smoothing capacitor connected with the output terminals of the rectifying circuit; a transformer having primary and secondary windings; a first series circuit which contains the first primary winding of the transformer and the first switching element, said first series circuit being connected with both ends of the smoothing capacitor; a second series circuit which contains the second primary winding of the transformer and the second switching element, said second series circuit being connected with both ends of the smoothing capacitor to generate DC output from the secondary winding of the transformer through a rectifier smoothing circuit by on and off operation of the switching element, the improvement comprising: first and second choke coils having primary and secondary windings respectively; and the primary winding of the first choke coil reconnected in series with the first primary winding of the transformer and the first switching element; the primary winding of the second choke oil being connected in series with the second primary winding of the transformer and the second switching element; the secondary winding of the first choke coil being connected between the rectifying circuit and the smoothing capacitor; and the secondary winding of the second choke coil being connected in parallel with the secondary winding of the first choke coil.

Claim 20

The DC converter as defined in Claim 19, wherein a first rectifying element is connected in series with the secondary winding of the first choke coil; and a second rectifying element is connected in series with the secondary winding of the second choke coil.

Claim 21

In a DC converter including a rectifying circuit connected with an AC power source; a smoothing capacitor connected with the output terminals of the rectifying circuit; a first series circuit which contains first and second switching elements, said first series circuit being connected with both ends of the smoothing capacitor; a second series circuit which contains first and second current resonance capacitors, said second series circuit being connected in parallel with the said first series circuit; a transformer having primary and secondary windings; the primary winding of the transformer connected between a joint portion of the first and second switching elements and a joint portion of the first and second current resonance capacitors; and first and second voltage resonance capacitors which are respectively connected in parallel with the first and second switching elements to generate DC output from the secondary winding of the transformer through a rectifier smoothing circuit by on and off operation of the first and second switching elements, the improvement comprising: first and second choke coils having primary and secondary windings respectively; a first rectifying element being connected in series with the primary winding of the first choke coil toward a direction that allows a current to flow in the first direction; and a second rectifying element connected in series with the primary winding of the second choke coil toward a direction that allows a current to flow in the second direction; and a third series circuit containing the primary winding of the first choke coil and the first rectifying element, said third series circuit being connected in series with the primary winding of the transformer; a fourth series circuit containing the primary winding of the second choke coil and the second rectifying element, said fourth series circuit being connected in parallel with the third series circuit; the secondary winding of the first choke coil being connected between the rectifying circuit and the smoothing capacitor; and the secondary winding of the second choke coil being connected in parallel with the secondary winding of the first choke coil.

Claim 22

The DC converter as defined in Claim 21, wherein a third rectifying element is connected in series with the secondary winding of the first choke coil; and a fourth rectifying element is connected in series with the secondary winding of the second choke coil.

Claim 23

In a DC converter including a rectifying circuit connected with an AC power source; a smoothing capacitor connected with the output terminals of the rectifying circuit; first and second switching elements connected in series with both ends of the smoothing capacitor; a transformer having primary and secondary windings; and a current resonance capacitor connected in series with the primary winding of the transformer which is connected with each of the first and second switching elements to generate DC output from the secondary winding of the transformer through a rectifier smoothing circuit by on and off operation of the first and second switching elements, the improvement comprising: a coil having primary and secondary windings; and the primary winding of the choke coil being connected in series in a circuit of the first and second switching elements; and the secondary winding of the choke coil being connected between the rectifying circuit and the smoothing capacitor.

Claim 24

The DC converter as defined in Claim 23, wherein first and second voltage resonance capacitors are respectively connected in parallel with the first and second switching elements.

Claim 25

The DC converter as defined in Claim 23 or 24, wherein a rectifying element is connected in series with the secondary winding of the choke coil.

Claim 26

The DC converter as defined in Claim 25, wherein another rectifying element is connected between a joint portion of the secondary winding of the choke coil and the rectifying element and a joint portion of the rectifying circuit and the smoothing capacitor.

Claim 27

In a DC converter including a rectifying circuit connected with an AC power source; a series circuit which contains first and second smoothing capacitors, said series circuit being connected with the output terminals of the rectifying circuit; a change means connected between a joint portion of the first and second smoothing capacitors and one end of the AC power source; first and second switching elements connected in series with both ends of the series circuit of the first and second smoothing capacitors; a transformer having primary and secondary windings; and a current resonance capacitor connected in series with the primary winding of the transformer and connected with each of the first and second switching elements to generate DC output from the secondary winding of the transformer through a rectifier smoothing circuit by on and off operation of the first and second switching elements, the improvement comprising: a choke coil having first to tertiary windings; and the primary winding of the choke coil being connected in series in a circuit of the first and second switching elements; and the secondary winding of the choke coil being connected between one of the output terminals of the rectifying circuit and the first smoothing capacitor; and the tertiary winding of the choke coil being connected between the other one of the output terminals of the rectifying circuit and the second smoothing capacitor.

Claim 28

The DC converter as defined in Claim 27, wherein first and second voltage resonance capacitors are respectively connected in parallel with the first and second switching elements.

Claim 29

The DC converter as defined in Claim 27 or 28, wherein a first rectifying element is connected in series with the secondary winding of the choke coil; and a second rectifying element is connected in series with the tertiary winding of the choke coil.

Claim 30

The DC converter as defined in Claim 29, wherein a third rectifying element is connected between a joint portion of the secondary winding of the choke coil and the first rectifying element and a joint portion of the first and second smoothing capacitors; and a fourth rectifying element is connected between a joint portion of the first and second smoothing capacitors and a joint portion of the tertiary winding of the choke coil and the second rectifying element.