Power source quality management system and air conditioner

Patent metadata

Field	Value
Publication number	US-11374487-B2
Application number	US-201816614861-A
Country	US
Kind code	B2
Filing date	May 30, 2018
Priority date	May 30, 2017
Publication date	Jun 28, 2022
Grant date	Jun 28, 2022

Abstract

A controller performs a first control for controlling the power source power factor or a power source harmonic of the harmonic current such that an input power factor of at least one of a plurality of connection devices changes in a direction preceding the power source power factor in a case where the power source power factor changes in a lagging direction, and performs a second control for controlling the power source power factor or the power source harmonic such that the input power factor of at least one of the connection devices changes in a direction lagging behind the power source power factor in a case where the power source power factor changes in a leading direction.

First claim

The invention claimed is:

1. A power source quality management system, comprising:
a load device that is connected to a power source and supplied with a power source electric power from the power source;
a plurality of connection devices, each including a harmonic generation device that is parallelly connected to the load device with respect to the power source and supplied with the power source electric power from the power source, and a current source whose output is parallelly connected to the harmonic generation device with respect to the power source; and
a controller configured to control a harmonic current flowing in a receiving channel from the power source to the load device and the harmonic generation devices or to control a power source power factor of the power source,
the controller being configured to:
perform a first control for controlling the power source power factor or a power source harmonic of the harmonic current such that an input power factor of at least one of the connection devices changes in a direction preceding the power source power factor in a case where the power source power factor changes in a lagging direction, and
perform a second control for controlling the power source power factor or the power source harmonic such that the input power factor of at least one of the connection devices changes in a direction lagging behind the power source power factor in a case where the power source power factor changes in the leading direction.

2. The power source quality management system of claim 1 , wherein
each of the current sources is able to generate a compensation current for performing at least one of reduction in harmonic current and improvement in a fundamental power factor of a corresponding one of the harmonic generation devices and the load device,
a calculation unit is further included, wherein, at a time of the first control and the second control performed by the controller, to make a sum of the harmonic current generated in the plurality of the harmonic generation devices and in the load device distributed among and compensated by the current sources and make a compensation amount of each of the current sources meet the condition of less than a maximum output capacity of each of the current sources, the calculation unit calculates an amount of the compensation current corresponding to the compensation amount to be generated by the corresponding one of the current sources, and
the controller performs, based on a calculation result of the calculation unit ( 90 ), the first control and the second control.

3. The power source quality management system of claim 2 , wherein
the calculation unit
calculates a first compensation amount, based on which each of the current sources compensates the harmonic current generated in part of the harmonic generation devices and the load device,
calculates a surplus amount for each of the current sources, the surplus amount being a difference between the maximum output capacity and the first compensation amount, and
calculates the compensation current of each of the current sources in accordance with the surplus amount.

4. The power source quality management system of claim 3 , wherein
the calculation unit calculates the compensation current of each of the current sources such that a second compensation amount increases as the surplus amount increases, the second compensation amount being used for making a sum of the harmonic current generated in a rest of the harmonic generation devices and the load device except for the part of the harmonic generation devices and the load device distributed and compensated.

5. The power source quality management system of claim 4 , wherein
the maximum output capacity is a maximum compensation current value indicating a maximum value of a current that can be generated by each of the current sources, and
the calculation unit calculates the surplus amount through subtraction of a current value of a first compensation corresponding to the first compensation amount from the maximum compensation current value.

6. The power source quality management system of claim 4 , wherein
the maximum output capacity is a maximum compensation electric power value indicating a maximum value of electric power that can be generated by each of the current sources, and
the calculation unit calculates the surplus amount through subtraction of an electric power value of a first compensation corresponding to the first compensation amount from the maximum compensation electric power value.

7. The power source quality management system of claim 2 , wherein
the power source is an AC power source, and
at least one of the harmonic generation devices is a power converter that is supplied with electric power from the power source.

8. An active filter device included in the power source quality management system of claim 2 , the active filter device being connected to the power source, the load device, and the harmonic generation device, comprising:
the current source; and
the controller in which the calculation unit is integrated.

9. An air conditioner, comprising the air-conditioning device of claim 8 .

10. The power source quality management system of claim 1 , wherein,
the plurality of connection devices are respectively included in air conditioners, and
the controller performs, in the first control and the second control, based on the harmonic current or the power source power factor, change of the input power factor or an input harmonic of the first air conditioner that is a part of the air conditioners to reduce the harmonic current or to make improvement through increase or decrease of the power source power factor, then changes an input power factor or an input harmonic of the second air conditioner that is a rest of the air conditioners except for the first air conditioner, to perform a power source quality improvement control for controlling the power source power factor or the power source harmonic.

11. The power source quality management system of claim 10 , further comprising
a target setting unit configured to set a target value of the harmonic current or of the power source power factor, wherein
the controller changes, in the power source quality improvement control, the harmonic current or the power source power factor to be close to the target value.

12. The power source quality management system of claim 11 , wherein
the target value is set to fall within a range of 0.9950 to 1.0049.

13. The power source quality management system of claim 10 , wherein
each of the air conditioners includes a power converter that is the harmonic generation device, and an active filter device that includes the current source and is connected to the power converter.

14. The power source quality management system of claim 13 , wherein
the controller stops, in the power source quality improvement control of the second control, an operation of the active filter device included in the first air conditioner.

15. The power source quality management system of claim 14 , wherein
the controller stops, in the power source quality improvement control of the second control, an operation of the active filter device included in the second air conditioner when the power source power factor after the stop of the active filter device included in the first air conditioner still changes in a leading direction.

16. The power source quality management system of claim 13 , wherein
the controller is integrated in the active filter device included in the first air conditioner.

17. The po

Assignees

• Daikin Ind Ltd

Inventors

• Kono Masaki
• Kawashima Reiji
• Fujita Takayuki

Classifications

• H02J3/1892

  the arrangements being an integral part of the loads or of their control circuits · CPC title

• H02M5/22

  using discharge tubes with control electrode or semiconductor devices with control electrode · CPC title

• F24F11/46

  Improving electric energy efficiency or saving · CPC title

• H02M1/4208 Primary

  Arrangements for improving power factor of AC input · CPC title

• H02M1/44

  Circuits or arrangements for compensating for electromagnetic interference in converters or inverters · CPC title