# US 12,113,431 B2 · Flying capacitor three-level converter and flying capacitor three-level buck-boost converter

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- Number: US 12,113,431 B2
- Document ID: US12113431B2
- Status: Granted
- Kind: B2
- Application number: 17/822,439
- Filed: 2022-08-26
- Published: 2023-03-09
- Granted: 2024-10-08
- Earliest claimed: 2021-09-07
- Assignees: Delta Electronics (Shanghai) Co., Ltd.
- Applicants: Delta Electronics (Shanghai) CO., LTD
- Inventors: Guoqiao Shen; Jinfa Zhang
- Web page: https://patentgrep.com/patent/US12113431B2

## CPC

- H02M 1/0095: {Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck}
- H02M 1/327: {against abnormal temperatures}
- H02M 3/003: {Constructional details, e.g. physical layout, assembly, wiring or busbar connections}
- H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps}
- H02M 3/158: including plural semiconductor devices as final control devices for a single load
- H02M 3/1582: {Buck-boost converters (H02M3/1584 takes precedence)}
- H02M 3/1584: {with a plurality of power processing stages connected in parallel}
- H02M 7/4837: {Flying capacitor converters}
- H05K 7/20909: {Forced ventilation, e.g. on heat dissipaters coupled to components}
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

Disclosed is a flying capacitor three-level converter, including a plurality of circuit units, wherein each of the plurality of circuit units includes: an input capacitor; a bridge arm, electrically connected with the input capacitor in parallel, wherein the bridge arm includes a first switch, a second switch, a third switch and a fourth switch electrically and sequentially connected in series; and a flying capacitor unit, wherein the flying capacitor unit includes a first capacitor and a second capacitor, and the first capacitor and the second capacitor are electrically connected in parallel and electrically connected with a series branch in parallel, and the series branch includes the second switch and the third switch; wherein the input capacitor, the first switch, the first capacitor and the fourth switch form a first switching loop, and the second capacitor, the second switch and the third switch form a second switching loop.

## Claims

### Claim 1

A flying capacitor three-level converter, comprising:
a plurality of circuit units, wherein each of the plurality of circuit units comprises:
an input capacitor;
a bridge arm, electrically connected with the input capacitor in parallel, wherein the bridge arm comprises a first switch, a second switch, a third switch and a fourth switch electrically and sequentially connected in series; and
a flying capacitor unit, wherein the flying capacitor unit comprises a first capacitor and a second capacitor, and the first capacitor and the second capacitor are electrically connected in parallel and electrically connected with a series branch in parallel, and the series branch comprises the second switch and the third switch;
wherein the input capacitor, the first switch, the first capacitor and the fourth switch form a first switching loop, and the second capacitor, the second switch and the third switch form a second switching loop;
wherein the converter further comprises a first heat dissipation unit and a second heat dissipation unit;
wherein the first switches and the fourth switches in all the first switching loops are arranged on the first heat dissipation unit;
wherein the second switches and the third switches in all the second switching loops are arranged on the second heat dissipation unit.

### Claim 2 (depends on 1)

The converter according to claim 1, wherein the first heat dissipation unit and the second heat dissipation unit have a same or similar heat dissipation condition.

### Claim 3 (depends on 1)

The converter according to claim 1, wherein the input capacitor and the first capacitor are located at a first side or a second side of the first heat dissipation unit, and the second side is corresponding to the first side with respect to the first heat dissipation unit; and
the second capacitor is located at a first side or a second side of the second heat dissipation unit, and the second side is corresponding to the first side with respect to the second heat dissipation unit.

### Claim 4 (depends on 1)

The converter according to claim 1, wherein the input capacitor and the first capacitor are arranged closer to the corresponding first switch and fourth switch than other power components; and
the second capacitor is arranged closer to the corresponding second switch and third switch than other power components.

### Claim 5 (depends on 1)

The converter according to claim 1, wherein a capacitance value of the first capacitor is different from a capacitance value of the second capacitor.

### Claim 6 (depends on 1)

The converter according to claim 1, wherein a distance between the first capacitor and the second capacitor is a preset distance.

### Claim 7 (depends on 1)

The converter according to claim 1, wherein all the bridge arms are electrically connected in parallel.

### Claim 8

A flying capacitor three-level buck-boost converter, comprising one or more circuit units, wherein each circuit unit of the one or more circuit units comprises a first flying capacitor unit, a second flying capacitor unit, an input capacitor, an output capacitor, an inductor, a first bridge arm and a second bridge arm;
the input capacitor is electrically connected in parallel with the first bridge arm, and the output capacitor is electrically connected in parallel with the second bridge arm;
the first bridge arm comprises a first switch, a second switch, a third switch, and a fourth switch, wherein the first switch, the second switch, the third switch and the fourth switch are sequentially connected in series;
the second bridge arm comprises a fifth switch, a sixth switch, a seventh switch, and an eighth switch, wherein the fifth switch, the sixth switch, the seventh switch and the eighth switch are sequentially connected in series;
the first flying capacitor unit comprises a first capacitor and a second capacitor, wherein the first capacitor and the second capacitor are electrically connected in parallel and are electrically connected in parallel with a first series branch, and the first series branch comprises the second switch and the third switch in the first bridge arm;
the input capacitor, the first switch, the first capacitor and the fourth switch form a first switching loop;
the second switch, the third switch and the second capacitor form a second switching loop;
the second flying capacitor unit comprises a third capacitor and a fourth capacitor, wherein the third capacitor and the fourth capacitor are electrically connected in parallel and are electrically connected in parallel with a second series branch, and the second series branch comprises the sixth switch and the seventh switch in the second bridge arm;
the output capacitor, the fifth switch, the third capacitor and the eighth switch form a third switching loop;
the sixth switch, the seventh switch and the fourth capacitor form a fourth switching loop; and
the inductor is coupled between a junction node of the second switch and the third switch in the first bridge arm and a junction node of the sixth switch and the seventh switch in the second bridge arm;
wherein the converter further comprises a first heat dissipation unit and a second heat dissipation unit;
wherein the first switches and the fourth switches in all the first switching loops are arranged on the first heat dissipation unit;
wherein the second switches and the third switches in all the second switching loops are arranged on the second heat dissipation unit;
wherein the fifth switches and the eighth switches in all the third switching loops are arranged on the first heat dissipation unit; and
wherein the sixth switches and the seventh switches in all the fourth switching loops are arranged on the second heat dissipation unit.

### Claim 9 (depends on 8)

The converter according to claim 8, wherein the first heat dissipation unit and the second heat dissipation unit have a same or similar heat dissipation condition.

### Claim 10 (depends on 8)

The converter according to claim 8, wherein
the input capacitor and the first capacitor in the first switching loop are located at a first side or a second side of the first heat dissipation unit, and the second side is corresponding to the first side with respect to the first heat dissipation unit;
the second capacitor in the second switching loop is located at a first side or a second side of the second heat dissipation unit, and the second side is corresponding to the first side with respect to the second heat dissipation unit;
the output capacitor and the third capacitor in the third switching loop are located at the first side or the second side of the first heat dissipation unit; and
the fourth capacitor in the fourth switch loop is located at the first side or the second side of the second heat dissipation unit.

### Claim 11 (depends on 8)

The converter according to claim 8, wherein
the input capacitor and the first capacitor are arranged closer to the corresponding first switch and fourth switch than other power components;
the second capacitor is arranged closer to the corresponding second switch and third switch than other power components;
the output capacitor and the third capacitor are arranged closer to the corresponding fifth switch and eighth switch than other power components; and
the fourth capacitor is arranged closer to the corresponding sixth switch and seventh switch than other power components.

### Claim 12 (depends on 8)

The converter according to claim 8, wherein the converter comprises at least two circuit units, and all the first bridge arms of the at least two circuit units are electrically connected in parallel, and all the second bridge arms of the at least two circuit units are electrically connected in parallel.

### Claim 13

A flying capacitor multilevel converter, comprising:
N circuit units, wherein each circuit unit of the N circuit units comprises m flying capacitor units, an input capacitor and a bridge arm, wherein Nis a positive integer greater than 1, and m is a positive integer greater than or equal to 2;
wherein the bridge arm comprises 2×(m+1) switches, and the 2×(m+1) switches are sequentially connected in series;
wherein each of the m flying capacitor units comprises a first capacitor and a second capacitor, and the first capacitor is electrically connected in parallel with the second capacitor;
wherein a first flying capacitor unit of the m flying capacitor units is electrically connected in parallel at both ends of a series branch which is defined by a second switch to the (2m+1)th switch, and the input capacitor, a first switch, the first capacitor of the first flying capacitor unit and the 2×(m+1)th switch form a first switching loop;
wherein the second capacitor of the first flying capacitor unit, the second switch, the first capacitor of a second flying capacitor unit of the m flying capacitor units and the (2m+1)th switch form a second switching loop;
wherein a kth flying capacitor unit of the m flying capacitor units is electrically connected in parallel at both ends of a series branch which is defined by the (k+1)th switch to the (2m+2−k)th switch, wherein k is a natural number from 2 to m;
wherein the second capacitor of the (k−1)th flying capacitor unit of the m flying capacitor units, a kth switch, the first capacitor of the kth flying capacitor unit and the (2m+3−k)th switch form a kth switching loop;
wherein the second capacitor of a mth flying capacitor unit of the m flying capacitor units, a (m+1)th switch and a (m+2)th switch form a (m+1)th switching loop;
wherein the converter further comprises (m+1) heat dissipation units;
wherein the first switches and the (2×(m+1))th switches in all the first switching loops are arranged on the first heat dissipation unit;
wherein the second switches and the (2m+1)th switches in all the second switching loops are arranged on the second heat dissipation unit;
wherein the kth switches and the (2m+3−k)th switches in all the kth switching loops are arranged on the kth heat dissipation unit;
wherein the (m+1)th switches and the (m+2)th switches in all the (m+1)th switching loops are arranged on the (m+1)th heat dissipation unit.

### Claim 14 (depends on 13)

The converter according to claim 13, wherein the (m+1) heat dissipation units have a same or similar heat dissipation condition.

### Claim 15 (depends on 13)

The converter according to claim 13,
wherein the input capacitor and the first capacitor of the first flying capacitor unit in the first switching loop are located at a first side or a second side of the first heat dissipation unit, and the second side is opposite to the first side with respect to the first heat dissipation unit;
wherein the second capacitor of the first flying capacitor unit and the first capacitor of the second flying capacitor unit in the second switching loop are located at a first side or a second side of the second heat dissipation unit, and the second side is opposite to the first side with respect to the second heat dissipation unit;
wherein the second capacitor of the (k−1)th flying capacitor unit and the first capacitor of the kth flying capacitor unit in the kth switching loop are located at a first side or a second side of the kth heat dissipation unit, and the second side is opposite to the first side with respect to the kth heat dissipation unit;
wherein the second capacitor of the mth flying capacitor unit in the (m+1)th switching loop is located at a first side or a second side of the (m+1)th heat dissipation unit, and the second side is opposite to the first side with respect to the (m+1)th heat dissipation unit.

### Claim 16 (depends on 13)

The converter according to claim 13,
wherein the input capacitor and the first capacitor of the first flying capacitor unit are arranged closer to the corresponding first switch and (2×(m+1))th switch than other power components;
wherein the second capacitor of the first flying capacitor unit and the first capacitor of the second flying capacitor unit are arranged closer to the corresponding second switch and (2m+1)th switch than other power components;
wherein the second capacitor of the (k−1)th flying capacitor unit and the first capacitor of the kth flying capacitor unit are arranged closer to the corresponding kth switch and (2m+3−k)th switch than other power components;
wherein the second capacitor of the mth flying capacitor unit is arranged closer to the corresponding (m+1)th switch and (m+2)th switch than other power components.

### Claim 17 (depends on 13)

The converter according to claim 13,
wherein a capacitance value of the first capacitor is different from a capacitance value of the second capacitor with respect to each of the m flying capacitor units.

### Claim 18 (depends on 13)

The converter according to claim 13, wherein all the bridge arms are electrically connected in parallel.