MATRIX CONVERTOR, POWER GENERATION SYSTEM, AND METHOD FOR CONTROLLING POWER FACTOR

• US 20160006345A1
• Filed: 07/03/2015
• Published: 01/07/2016
• Est. Priority Date: 07/04/2014
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Yaskawa Denki
• Original Assignee: Kabushiki Kaisha Yaskawa Denki
• Inventors: YOSHINAGA, Wataru, TANAKA, Takashi, INOMATA, Kentaro, TAKEDA, Kotaro, NAKA, Takuya
• Granted Patent: US 9,923,456 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02M 1/126 using passive filters
• CPC Class Codes: H02M 1/42 Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 5/297 for conversion of frequency
• CPC Class Codes: H02P 21/22 Current control, e.g. using a current control loop
• CPC Class Codes: H02P 23/26 Power factor control [PFC]
• CPC Class Codes: H02P 27/16 using ac to ac converters without intermediate conversion to dc H02P27/05 takes precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A matrix convertor includes a power convertor and a controller. The power convertor is disposed between a power system and a rotating electric machine, and includes a plurality of bidirectional switches. The controller is configured to control an exciting current flowing from the power convertor to the rotating electric machine so as to control a power factor on a side of the power system.

Claims

1. A matrix convertor comprising:

a power convertor disposed between a power system and a rotating electric machine and comprising a plurality of bidirectional switches; and

a controller configured to control an exciting current flowing from the power convertor to the rotating electric machine so as to control a power factor on a side of the power system.

2. The matrix convertor according to claim 1, wherein the controller comprises

a detector configured to detect at least one of reactive power and a reactive current supplied from the matrix convertor to the power system, and

a current command generator configured to generate an exciting current command based on at least one of the reactive power and the reactive current detected by the detector.

3. The matrix convertor according to claim 2,

wherein the controller comprises

a power factor command generator configured to generate a power factor command for the power system to make at least one of the reactive current and the reactive power have a predetermined value, and

a limiter configured to limit the power factor command within a predetermined range, and

wherein the current command generator is configured to generate the exciting current command based on a difference between the power factor command and an output of the limiter.

4. The matrix convertor according to claim 2, wherein the current command generator is configured to generate the exciting current command based on at least one of the reactive power and the reactive current when a rotation speed of the rotating electric machine is equal to or lower than a predetermined value.

5. A power generation system comprising a power generator comprising a rotating electric machine, the rotating electric machine comprising:

a power convertor disposed between a power system and a rotating electric machine and comprising a plurality of bidirectional switches; and

a controller configured to control an exciting current flowing from the power convertor to the rotating electric machine so as to control a power factor on a side of the power system.

6. A method for controlling a power factor, the method comprising:

detecting a reactive current or reactive power supplied from a matrix convertor to a power system, the matrix convertor comprising a power convertor disposed between the power system and a rotating electric machine, the power convertor comprising a plurality of bidirectional switches; and

controlling an exciting current flowing from the power convertor to the rotating electric machine so as to control a power factor on a side of the power system based on at least one of the reactive current and the reactive power.

7. The method according to claim 6, wherein the controlling step comprises

generating an exciting current command based on at least one of the detected reactive power and the detected reactive current, and

controlling the power convertor based on the exciting current command.

8. The method according to claim 7, further comprising:

generating a power factor command for the power system to make at least one of the reactive current and the reactive power have a predetermined value; and

limiting the power factor command within a predetermined range,

wherein the exciting current command generating step comprises generating the exciting current command based on a difference between a first value and a second value of the power factor command, the first value being a value before the power factor command is limited, the second value being a value after the power factor command has been limited.

9. A matrix convertor comprising:

a power convertor disposed between a power system and a rotating electric machine and comprising a plurality of bidirectional switches; and

means for controlling an exciting current flowing from the power convertor to the rotating electric machine so as to control a power factor on a side of the power system.