# US 2010/0165688 A1 · Cascaded flying capacitor modular high voltage inverters

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- Number: US 2010/0165688 A1
- Document ID: US20100165688A1
- Status: Published application
- Kind: A1
- Application number: 12/347,185
- Filed: 2008-12-31
- Published: 2010-07-01
- Earliest claimed: 2008-12-31
- Assignees: Drs Power & Control Technolgies, Inc.
- Inventors: Ashish R. Bendre; Slobodan Krstic
- Web page: https://patentgrep.com/patent/US20100165688A1

## CPC

- H02M 7/49: Combination of the output voltage waveforms of a plurality of converters
- H02M 7/4837: {Flying capacitor converters}
- 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)

## Abstract

A high voltage inverter is provided which includes a plurality of k-level flying capacitor H bridge modules, k being greater than 2, each having a positive dc terminal, a negative dc terminal, and two ac terminals, a connecting unit for connecting said ac terminals of said plurality of k-level flying capacitor H bridge modules in series to form a cascading set of modules, and a dc source connected to an ac source and having a transformer, a rectifier rectifying an output voltage of said transformer, and a capacitor connected between the positive and negative dc terminals.

## Claims

### Claim 1

A high voltage inverter comprising:
a plurality of k-level flying capacitor H bridge modules, k being greater than 2, each having:
a positive dc terminal, a negative dc terminal, and two ac terminals;
a connecting unit for connecting said ac terminals of said plurality of k-level flying capacitor H bridge modules in series to form a cascading set of modules; and
a dc source connected to an ac source and having a transformer, a rectifier rectifying an output voltage of said transformer, and a capacitor connected between the positive and negative dc terminals.

### Claim 2 (depends on 1)

A high voltage inverter according to claim 1, wherein when k is equal to three, each of the k-level flying capacitor modules is a three-level flying capacitor module and includes:
first and second poles, each containing four switching devices and a flying capacitor,
a first pair of said four switching devices is connected between said positive dc terminal and the first of said ac output terminals,
a second pair of said four switching devices is connected between the first of said ac output terminals and said negative dc terminal, and
a first connection of said flying capacitor is between said first pair of switching devices, and a second connection is between said second pair of switching devices.

### Claim 3 (depends on 1)

A high voltage inverter according to claim 1, wherein when k is equal to four, each of the k-level flying capacitor modules is a four-level flying capacitor module and includes:
first and second poles, each containing six switching devices each and two flying capacitors,
a first set of three of said six switching devices is connected between said positive dc terminal and the first of said ac output terminals,
a second set of three of said six switching devices is connected between the first of said ac output terminals and said negative dc terminal,
a first connection of the first of said two flying capacitors is between the first and second switching devices in said first set of three switching devices, and a second connection of the first of said two flying capacitors is between the second and third switching devices in said second set of three switches, and
a first connection of the second of said two flying capacitors is between the second and third switching devices in said first set of three switching devices, and a second connection of the second of said two flying capacitors is between the first and second switching devices of said second set of three switching devices.

### Claim 4 (depends on 1)

A high voltage inverter according to claim 1, wherein said rectifier is a three-phase passive rectifier having three ac input connections and two dc output connections and a zig-zag implementation of said transformer.

### Claim 5 (depends on 1)

A high voltage inverter according to claim 1, wherein said rectifier includes a plurality of three phase two level active rectifiers, each having three ac input connections and two dc output connections and a mechanism to stack said three phase two level active rectifiers using a series connection of said dc terminals.

### Claim 6 (depends on 5)

A high voltage inverter according to claim 5, wherein each of said three level three phase flying capacitor modules includes:
first, second and third poles, each containing four switching devices and a flying capacitor,
a first pair of said four switching devices is connected between said positive dc terminal and the first of said ac output terminals,
a second pair of said four switching devices is connected between the first of said ac output terminals and said negative dc terminal, and
a first connection of said flying capacitor is between said first pair of switches, and a second connection is between said second pair of switches.

### Claim 7 (depends on 5)

A high voltage inverter according to claim 5, wherein each of said three level three phase flying capacitor modules includes:
first, second and third poles, each containing six switching devices each and two flying capacitors,
a first set of three of said six switching devices is connected between said positive dc terminal and the first of said ac output terminals,
a second set of three of said six switching devices is connected between the first of said ac output terminals and said negative dc terminal,
a first connection of the first of said two flying capacitors is between the first and second switching devices in said first set of three switching devices, and a second connection of the first of said two flying capacitors is between the second and third switching devices in said second set of three switches, and
a first connection of the second of said two flying capacitors is between the second and third switching devices in said first set of three switching devices, and a second connection of the second of said two flying capacitors is between the first and second switching devices of said second set of three switching devices.