AC-DC converter for wide range output voltage and high switching frequency
View Patent ↗An electrical circuit includes an input for an AC input voltage coupled to a first inductive element with first and second outputs coupled to respective first and second nodes, and a four-quadrant (4-Q) switch coupled between the first and second nodes. A capacitor is coupled between the first node and a third node, a second inductive element is coupled between the third node and the second node, and a first bidirectional device and a first diode are coupled in series between a positive output node and a negative output node. A first output of the second inductive element is coupled between the first bidirectional device and the first diode. A second bidirectional device and a second diode are coupled in series between the positive output node and the negative output node. A second output of the second inductive element is coupled between the second bidirectional device and the second diode.
1. An electrical circuit comprising:
an input operable to receive an AC input voltage;
a first inductive element coupled to the input and having first and second outputs connected to respective first and second nodes;
a four-quadrant (4-Q) switch connected between the first and second nodes;
a capacitor connected between the first node and a third node;
a second inductive element connected between the third node and the second node;
a first bidirectional device and a first diode connected in series between a positive output node and a negative output node, wherein a first terminal of the second inductive element is connected to a first conductor between the first bidirectional device and the first diode; and
a second bidirectional device and a second diode connected in series between the positive output node and the negative output node, wherein a second terminal of the second inductive element is connected to a second conductor between the second bidirectional device and the second diode.
2. The electrical circuit of claim 1 further comprising a control circuit configured to:
sense the AC input voltage; and
control the 4-Q switch, the first bidirectional device, and the second bidirectional device such that an input current substantially follows a waveform of the AC input voltage, while regulating the dc voltage at the output terminals.
3. The electrical circuit of claim 1 wherein at least one of the first bidirectional device or the second bidirectional device comprises a field-effect transistor (FET) in series with a diode.
4. The electrical circuit of claim 3 wherein either or both of the FET or the diode comprises at least one of silicon carbide (SiC) or gallium nitride (GaN).
5. The electrical circuit of claim 1 wherein the 4-Q switch comprises:
a first FET connected between the first node and a fourth node;
a second FET connected between the second node and the fourth node;
a third diode connected between the first node and the fourth node; and
a fourth diode connected between the second node and the fourth node;
wherein an input of the first FET and an input of the second FET are configured to operate the 4-Q switch.
6. The electrical circuit of claim 1 wherein the 4-Q switch comprises:
a third diode and a fourth diode connected to the first node;
a fifth diode and a sixth diode connected to the second node; and
a FET connected between:
a node connecting the third diode with the fifth diode, and
a node connecting the fourth diode with the sixth diode;
wherein an input of the FET is configured to operate the 4-Q switch.
7. The electrical circuit of claim 1 wherein:
the second inductive element comprises an inductor connected to each of the second and third nodes.
8. The electrical circuit of claim 1 wherein:
the second inductive element comprises a coupled inductor having:
a first winding connected between the second node and the third node; and
a second winding connected between a fourth node and a fifth node;
wherein:
the fourth node is connected to the first conductor, and
the fifth node is connected to the second conductor.
9. A method of manufacturing an electrical circuit, the method comprising:
providing a first inductive element operable to receive an AC input voltage and having first and second outputs comprising respective first and second nodes;
connecting a four-quadrant (4-Q) switch between the first and second nodes;
connecting a capacitor between the first node and a third node;
connecting a second inductive element between the third node and the second node;
connecting a first bidirectional device and a first diode in series between a positive output node and a negative output node;
connecting a first terminal of the second inductive element to a first conductor between the first bidirectional device and the first diode;
connecting a second bidirectional device and a second diode in series between the positive output node and the negative output node; and
connecting a second terminal of the second inductive element to a first conductor between the second bidirectional device and the second diode.
10. The method of claim 9 further comprising connecting a control circuit to the first inductive element, the 4-Q switch, the first bidirectional device, and the second bidirectional device such that the control circuit is operable to:
sense the AC input voltage; and
control the 4-Q switch, the first bidirectional device, and the second bidirectional device such that an input current substantially follows a waveform of the AC input voltage.
11. The method of claim 9 wherein at least one of the first bidirectional device or the second bidirectional device comprises a field-effect transistor (FET) in series with a diode.
12. The method of claim 11 wherein either or both of the FET or the diode comprises at least one of silicon carbide (SiC) or gallium nitride (GaN).
13. The method of claim 9 wherein the 4-Q switch comprises:
a first FET connected between the first node and a fourth node;
a second FET connected between the second node and the fourth node;
a third diode connected between the first node and the fourth node; and
a fourth diode connected between the second node and the fourth node;
wherein an input of the first FET and an input of the second FET are configured to operate the 4-Q switch.
14. The method of claim 9 wherein the 4-Q switch comprises:
a third diode and a fourth diode connected to the first node;
a fifth diode and a sixth diode connected to the second node; and
a FET coupled between:
a node connecting the third diode with the fifth diode, and
a node connecting the fourth diode with the sixth diode;
wherein an input of the FET is configured to operate the 4-Q switch.
15. The method of claim 9 wherein connecting the second inductive element comprises connecting an inductor between the third node and the second node.
16. The method of claim 9 wherein connecting the second inductive element between the third node and the second node comprises:
connecting a first winding of a coupled inductor between the second node and the third node; and
connecting a second winding of the coupled inductor between a fourth node and a fifth node;
such that:
the fourth node is connected to the first conductor, and
the fifth node is connected to the second conductor.