Power conversion device with a plurality of series circuits

• US 9,917,534 B2
• Filed: 08/26/2016
• Issued: 03/13/2018
• Est. Priority Date: 03/30/2009
• Status: Active Grant

• Current Assignee: Hitachi Industrial Products, Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Inoue, Shigenori, Katoh, Shuji, Narushima, Jun, Kato, Tetsuya
• Primary Examiner(s): Ahmed, Yusef
• Application Number:
  US15/248,142
• Publication Number:
  US 20160365807A1
• Time in Patent Office: 564 Days
• CPC Class Codes: H01F 27/42 Circuits specially adapted for the purpose of modifying, or compensating for, electric characteristics of transformers, reactors, or choke coils circuits for controlling transformers, reactors or choke coils, for the purpose of obtaining a desired output H02P13/00; impedance networks H03H
• CPC Class Codes: H02J 3/1857 wherein such bridge converter is a multilevel converter
• CPC Class Codes: H02J 3/36 Arrangements for transfer of electric power between ac networks via a high-tension dc link
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• CPC Class Codes: H02M 7/219 in a bridge configuration
• CPC Class Codes: H02M 7/4835 comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
• CPC Class Codes: H02M 7/5388 with asymmetrical configuration of switches
• CPC Class Codes: H02M 7/797 using semiconductor devices only
• CPC Class Codes: Y02E 40/20 Active power filtering [APF]
• CPC Class Codes: Y02E 60/60 Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

Abstract

A power conversion device is provided which includes a plurality of series circuits each formed of a voltage source and a controlled current source. At least two of said series circuits formed of the voltage source and the controlled current source are connected in parallel. Further, parallel connection points of the series circuits connected in parallel form output terminals.

Claims

1. A power conversion device comprising:

three series circuits each comprised of a plurality of unit converters and windings connected in series to one another,

wherein respective ends on one side of the three series circuits are connected to form a one-side terminal and respective ends on the other side of the three series circuits are connected to form an other-side terminal,

each of the plurality of unit converters includes a capacitor and a switching device adapted to output an electric power from the capacitor or to input an electric power to the capacitor,

power conversion is performed between an electric power appearing between the one-side terminal and the other-side terminal, and an electric power to be input to or output from the three series circuits lying between the one-side terminal and the other-side terminal, and

one winding of the plurality of windings is magnetically coupled to any other one winding of the plurality of windings so as to cancel electromotive force generated in the one winding without generating a magnetic flux, and wherein a zero-phase DC current is configured to flow in the one winding when the power conversion device transmits and receives electric power to or from a power system.

2. The power conversion device of claim 1, wherein each of the plurality of unit converters comprises a full bridge converter.

3. The power conversion device of claim 1, wherein each of the plurality of unit converters comprises a bi-directional chopper converter.

4. The power conversion device of claim 1, wherein each of the plurality of windings are configured so that a magnetomotive force caused by the zero-phase DC current becomes zero.

5. A power conversion device comprising:

three series circuits each comprised of a plurality of unit converters and a winding on one side of a transformer connected in series to one another,

wherein the three series circuits are connected in parallel to one another between a one-side terminal and an other-side terminal,

respective ends on one side of the three series circuits are connected to form the one-side terminal and respective ends on the other side of the three series circuits are connected to form the other-side terminal,

each of the plurality of unit converters includes a capacitor and a switching device adapted to output an electric power from the capacitor or to input an electric power to the capacitor,

power conversion is performed between an electric power appearing between the one-side terminal and the other-side terminal, and an electric power to be input to or output from the three series circuits lying between the one-side terminal and the other-side terminal, and

the plurality of unit converters, connected in series, output a voltage so as to allow a voltage of each of the three series circuits to approximate to a direct current, and wherein each of the windings are configured so that a magnetomotive force caused by a zero-phase current becomes zero.

6. The power conversion device of claim 5, wherein each of the plurality of unit converters comprises a full bridge converter.

7. The power conversion device of claim 5, wherein each of the plurality of unit converters comprises a bi-directional chopper converter.

8. A power conversion device comprising:

three series circuits each comprised of a first plurality of unit converters, first windings, second windings and a second plurality of unit converters connected in series to one another,

wherein the three series circuits are connected in parallel to one another between DC terminals,

each of the first and second plurality of unit converters includes a capacitor and is configured to input an electric power to or to output an electric power from the capacitor through a switching device, and

any one winding of the first or second windings is magnetically coupled to any other one winding of the first or second windings so as to cancel an electromotive force generated in any one winding of the first or second windings without generating a magnetic flux, and wherein a zero-phase DC current is configured to flow in any one winding of the first or second windings when the power conversion device transmits and receives electric power.

9. The power conversion device of claim 8, wherein each of the first and second plurality of unit converters comprises a full bridge converter.

10. The power conversion device of claim 8, wherein each of the first and second plurality of unit converters comprises a bi-directional chopper converter.

11. The power conversion device of claim 8, wherein each of the first and second windings are configured so that a magnetomotive force caused by the zero-phase DC current becomes zero.

12. A method of performing a power conversion comprising:

providing a power conversion device including;

three series circuits each comprised of a plurality of unit converters and windings connected in series to one another,

wherein respective ends on one side of the three series circuits are connected to form a one-side terminal and respective ends on the other side of the three series circuits are connected to form an other-side terminal,

each of the plurality of unit converters includes a capacitor and a switching device adapted to output an electric power from the capacitor or to input an electric power to the capacitor, and

one winding of the plurality of windings is magnetically coupled to any other one winding of the plurality of windings so as to cancel electromotive force generated in the one winding without generating a magnetic flux, and wherein a zero-phase DC current is configured to flow in the one winding when the power conversion device transmits and receives electric power; and

receiving an electric power between the one-side terminal and the other side-terminal;

wherein power conversion is performed between the electric power appearing between the one-side terminal and the other-side terminal, and an electric power to be input to or output from the three series circuits lying between the one-side terminal and the other-side terminal.