ACTIVE FILTER AND AC-DC CONVERSION DEVICE

• US 20170237334A1
• Filed: 09/29/2015
• Published: 08/17/2017
• Est. Priority Date: 10/15/2014
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: KAWASHIMA, Reiji, FUJITA, Takayuki
• Granted Patent: US 10,110,113 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 3/01 Arrangements for reducing harmonics or ripples
• CPC Class Codes: H02K 7/14 Structural association with mechanical loads, e.g. with hand-held machine tools or fans with fan or impeller for cooling the machine H02K9/06
• CPC Class Codes: H02M 1/084 using a control circuit common to several phases of a multi-phase system
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: H02M 7/08 arranged for operation in parallel
• CPC Class Codes: H02M 7/219 in a bridge configuration
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: H03H 11/02 Multiple-port networks
• 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

An active filter is connected in parallel to a rectifier circuit between a set of AC input lines and a pair of DC buses. The active filter includes a capacitor, a pair of current limiting elements and an inverter. One in the current limiting elements is disposed between one end of the capacitor and one in the DC buses. Other in the current limiting elements is disposed between other end of the capacitor and other in the DC buses. At least one of the current limiting elements is disposed in an orientation to be forward with respect to a DC voltage outputted by the rectifier circuit. The inverter includes: a set of AC-side terminals connected to the set of AC input lines; and a pair of DC-side terminals connected to both ends of the capacitor.

Claims

1-8. -8. (canceled)

9. An active filter connected in parallel to a rectifier circuit between a set of AC input lines and a pair of DC buses between which a load is connected, said rectifier circuit rectifying AC voltages inputted from said set of AC input lines and outputting a DC voltage to said pair of DC buses, said active filter comprising:

a first capacitor;

a pair of current limiting elements, each of which connects each of a pair of ends of said first capacitor to each of said pair of DC buses, and at least one of which is a diode disposed in an orientation to be forward with respect to said DC voltage; and

an inverter including a set of AC-side terminals connected to said set of AC input lines, a pair of DC-side terminals connected to both ends of said first capacitor, a plurality of switching elements, each of which connects each of said AC-side terminals and each of said DC-side terminals to each other, and a plurality of diodes, each of which is connected in anti-parallel to each of said switching elements.

10. The active filter according to claim 9, wherein each of said pair of current limiting elements is the diode disposed in the orientation to be forward with respect to the DC voltage.

11. The active filter according to claim 9, wherein other in said pair of current limiting elements is a resistor.

12. The active filter according to claim 9,

wherein said rectifier circuit includes a diode bridge and a low-pass filter,

said low-pass filter is provided between said diode bridge and said pair of DC buses,

said diode bridge is provided between said set of AC input lines and said low-pass filter,

said low-pass filter includes:

a first reactor provided between one in said pair of DC buses and said diode bridge;

a second reactor provided between other in said pair of DC buses and said diode bridge; and

a second capacitor provided between said pair of DC buses.

13. The active filter according to claim 9, further comprising:

a clamp circuit, which is provided between said first capacitor and said pair of current limiting elements, and includes at least one of clamping diodes reverse to said DC voltage, and a clamping capacitor connected in parallel to said first capacitor via said clamping diode more on said first capacitor side than said one in said pair of current limiting elements,

wherein said pair of current limiting elements are connected in series to said clamping capacitor between said pair of DC buses, and

said one in said pair of current limiting elements is connected to one in a pair of ends of said first capacitor via said clamping diode.

14. The active filter according to claim 13, wherein said clamp circuit further includes other clamping diode, which is connected in series to said clamping diode and said clamping capacitor between said pair of ends of said first capacitor and is reverse to said DC voltage.

15. The active filter according to claim 13, further comprising:

a third reactor and a fourth reactor, which are inductively coupled to each other at a same polarity, wherein

said third reactor is connected in series to said one in said pair of current limiting elements between said one in said pair of ends of said first capacitor and one in said DC buses,

said fourth reactor is connected in series to other in said pair of current limiting elements between other in said pair of ends of said first capacitor and other in said DC buses, and

each of said third reactor and said fourth reactor is on said first capacitor side with respect to said clamping capacitor, or on an opposite side to said first capacitor.

16. The active filter according to claim 14, further comprising:

a third reactor and a fourth reactor, which are inductively coupled to each other at a same polarity, wherein

said third reactor is connected in series to said one in said pair of current limiting elements between said one in said pair of ends of said first capacitor and one in said DC buses,

said fourth reactor is connected in series to other in said pair of current limiting elements between other in said pair of ends of said first capacitor and other in said DC buses, and

each of said third reactor and said fourth reactor is on said first capacitor side with respect to said clamping capacitor, or on an opposite side to said first capacitor.

17. An AC-DC conversion device comprising:

the active filter according to claim 9; and

said rectifier circuit.

18. An AC-DC conversion device comprising:

the active filter according to claim 10; and

said rectifier circuit.

19. An AC-DC conversion device comprising:

the active filter according to claim 11; and

said rectifier circuit.

20. An AC-DC conversion device comprising:

the active filter according to claim 12; and

said rectifier circuit.

21. An AC-DC conversion device comprising:

the active filter according to claim 13; and

said rectifier circuit.

22. An AC-DC conversion device comprising:

the active filter according to claim 14; and

said rectifier circuit.

23. An AC-DC conversion device comprising:

the active filter according to claim 15; and

said rectifier circuit.

24. An AC-DC conversion device comprising:

the active filter according to claim 16; and

said rectifier circuit.