Power converter and its control method and air conditioner

• US 8,269,370 B2
• Filed: 04/12/2007
• Issued: 09/18/2012
• Est. Priority Date: 04/19/2006
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Haga, Hitoshi
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Fauth, Justen
• Application Number:
  US12/226,434
• Publication Number:
  US 20090102285A1
• Time in Patent Office: 1,986 Days
• Field of Search: 307/25, 307/11
• US Class Current: 307/25
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 5/458 using semiconductor devices only

Abstract

A controller (10) includes subtracters (101, 105), a command value corrector (103), and a control block (102). The subtracter (101) obtains a deviation (Δv0) of an output voltage (v0) applied from a switching power-supply circuit (61) to a second load (Cdc+Load) with respect to its command value (v0*). The control block (102) performs PI control on the basis of the deviation (Δv0) to generate a command value (idc*) for a current (idc) flowing in a coil (Ldc). The command value corrector (103) corrects the command value (idc*) such that high-frequency components of a current (iL) flowing in a first power-supply line (21), with respect to the fundamental frequency of an input current (iu1, iv1, iw1), are consumed in the switching power-supply circuit (61). The subtracter (105) obtains a deviation (Δidc) between the corrected command value (idc*) and the current (idc). Commands (r1, r2) for switches are generated on the basis of the deviation (Δidc).

Claims

1. A power converter comprising:

a rectifier circuit that rectifies an input current from an alternating-current power supply and outputs a direct-current voltage between a first power-supply line and a second power-supply line, so as to apply said direct-current voltage to a first load;

a capacitor connected between said first power-supply line and said second power-supply line; and

a switching power-supply circuit connected between said first power-supply line and said second power-supply line, said switching power-supply circuit performing a switching operation with a duty based on a first current flowing in said first power-supply line, to supply power to a second load from a high-frequency component of said first current with respect to a fundamental frequency of said input current, wherein

said switching power-supply circuit is connected to said second load on an output side thereof, and

said switching power-supply circuit is connected to a third power-supply line and a fourth power-supply line each of which branching from said first power-supply line and said second power-supply line on the input side thereof.

2. The power converter according to claim 1, wherein said switching power-supply circuit comprises a switch that performs said switching operation according to a command value that is obtained on the basis of:

a deviation of an output voltage applied to said second load from said switching power-supply circuit with respect to its command value; and

said first current.

3. The power converter according to claim 2, wherein said switch performs said switching operation according to a second command value that is obtained on the basis of:

said command value and a second current flowing in said second load.

4. The power converter according to claim 2,

wherein said first load comprises a main load and an inverter that receives a voltage across both ends of said capacitor and outputs an alternating current to said main load, and

said duty is determined by a comparison between said command value and a carrier for said inverter.

5. The power converter according to claim 1,

wherein said second load is a motor, and

said switching power-supply circuit comprises a switch that performs said switching operation according to a command value that is obtained on the basis of:

a deviation of a rotating speed of said motor with respect to its command value; and

said first current.

6. The power converter according to claim 1, wherein said switching power-supply circuit comprises a switch that performs said switching operation according to a command value that is obtained on the basis of:

said first current and a second current flowing in said second load.

7. The power converter according to claim 1,

wherein said first load comprises a main load and an inverter that receives a voltage across both ends of said capacitor and outputs an alternating current to said main load.

8. The power converter according to claim 1, wherein said switching power-supply circuit subtracts a correction value obtained by multiplying said first current and the predetermined value from a command value to said switching operation to correct said command value, and performs said switching operation based on corrected said command value.

9. A power converter comprising:

a rectifier circuit that rectifies an input current from an alternating-current power supply and outputs a direct-current voltage between a first power-supply line and a second power-supply line, so as to apply said direct-current voltage to a first load;

a capacitor connected between said first power-supply line and said second power-supply line;

a reactor constituting a serial resonant circuit together with said capacitor; and

a switching power-supply circuit connected between said first power-supply line and said second power-supply line, said switching power-supply circuit performing a switching operation with a duty based on a first voltage applied to said reactor, to supply power to a second load from a high-frequency component of a first current flowing in said first power-supply line with respect to a fundamental frequency of said input current, wherein

said switching power-supply circuit is connected to said second load on an output side thereof, and

said switching power-supply circuit is connected to a third power-supply line and a fourth power-supply line each of which branching from said first power-supply line and said second power-supply line on the input side thereof.

10. The power converter according to claim 9, wherein said switching power-supply circuit comprises a switch that performs said switching operation according to a command value that is obtained on the basis of:

a deviation of an output voltage applied to said second load from said switching power-supply circuit with respect to its command value; and

said first voltage.

11. The power converter according to claim 9,

wherein said second load is a motor, and

said switching power-supply circuit comprises a switch that performs said switching operation according to a command value that is obtained on the basis of:

a deviation of a rotating speed of said motor with respect to its command value; and

said first voltage.

12. The power converter according to claim 9, wherein said switching power-supply circuit comprises a switch that performs said switching operation according to a command value that is obtained on the basis of:

said first voltage and a second current flowing in said second load.

13. The power converter according to claim 9, wherein said switching power-supply circuit subtracts a correction value obtained by multiplying said first voltage and the predetermined value from a command value to said switching operation to correct said command value, and performs said switching operation according to corrected said command value.

14. An air conditioner comprising:

a power converter that comprises a rectifier circuit that rectifies an input current from an alternating-current power supply and outputs a direct-current voltage between a first power-supply line and a second power-supply line, so as to apply said direct-current voltage to a first load;

a capacitor connected between said first power-supply line and said second power-supply line; and

a switching power-supply circuit connected between said first power-supply line and said second power-supply line, said switching power-supply circuit performing a switching operation with a duty based on a first current flowing in said first power-supply line, to supply power to a second load from a high-frequency component of said first current with respect to a fundamental frequency of said input current, said first load comprising a main load and an inverter that receives a voltage across both ends of said capacitor and outputs an alternating current to said main load;

a motor for a refrigerant compressor, said motor forming said main load; and

an air-cooling fan that forms said second load,

said air conditioner performing air conditioning by operating said fan to remove latent heat of a refrigerant compressed by said refrigerant compressor, and

said switching power-supply circuit is connected to a third power-supply line and a fourth power-supply line each of which branching from said first power-supply line and said second power-supply line on the input side thereof.

15. A power converter controlling method for controlling a power converter, said power converter comprising:

a rectifier circuit that rectifies an input current from an alternating-current power supply and outputs a direct-current voltage between a first power-supply line and a second power-supply line, so as to apply said direct-current voltage to a first load;

a capacitor connected between said first power-supply line and said second power-supply line; and

a switching power-supply circuit connected between said first power-supply line and said second power-supply line,

said power converter controlling method causing said switching power-supply circuit to perform a switching operation with a duty based on a first current flowing in said first power-supply line, to supply power to a second load from a high-frequency component of said first current with respect to a fundamental frequency of said input current, wherein

said switching power-supply circuit is connected to said second load on an output side thereof, and

said switching power-supply circuit is connected to a third power-supply line and a fourth power-supply line each of which branching from said first power-supply line and said second power-supply line on the input side thereof.

16. The power converter controlling method according to claim 15, which causes said switching power-supply circuit to perform said switching operation according to a command value that is obtained on the basis of:

a deviation of an output voltage applied to said second load from said switching power-supply circuit with respect to its command value; and

said first current.

17. The power converter controlling method according to claim 16, which causes said switching power-supply circuit to perform said switching operation according to a second command value that is obtained on the basis of:

said command value and a second current flowing in said second load.

18. The power converter controlling method according to claim 16,

wherein said first load comprises a main load and an inverter that receives a voltage across both ends of said capacitor and outputs an alternating current to said main load, and

said duty is determined by a comparison between said command value and a carrier for said inverter.

19. The power converter controlling method according to claim 15,

wherein said second load is a motor, and

said power converter controlling method causes said switching power-supply circuit to perform said switching operation according to a command value that is obtained on the basis of:

a deviation of a rotating speed of said motor with respect to its command value; and

said first current.

20. The power converter controlling method according to claim 15, which causes said switching power-supply circuit to perform said switching operation according to a command value that is obtained on the basis of:

said first current and a second current flowing in said second load.

21. The power converter controlling method according to claim 15, which causes said switching power-supply circuit to perform said switching operation according to a command value that is obtained by subtracting a correction value obtained by multiplying said first current and the predetermined value from a command value to said switching operation.

22. A power converter controlling method for controlling a power converter, said power converter comprising:

a rectifier circuit that rectifies an input current from an alternating-current power supply and outputs a direct-current voltage between a first power-supply line and a second power-supply line, so as to apply said direct-current voltage to a first load;

a capacitor connected between said first power-supply line and said second power-supply line;

a reactor constituting a serial resonant circuit together with said capacitor; and

a switching power-supply circuit connected between said first power-supply line and said second power-supply line,

said power converter controlling method causing said switching power-supply circuit to perform a switching operation with a duty based on a first voltage applied to said reactor, to supply power to a second load from a high-frequency component of a first current flowing in said first power-supply line with respect to a fundamental frequency of said input current, wherein

said switching power-supply circuit is connected to said second load on an output side thereof, and

said switching power-supply circuit is connected to a third power-supply line and a fourth power-supply line each of which branching from said first power-supply line and said second power-supply line on the input side thereof.

23. The power converter controlling method according to claim 22, which causes said switching power-supply circuit to perform said switching operation according to a command value that is obtained on the basis of:

a deviation of an output voltage applied to said second load from said switching power-supply circuit with respect to its command value; and

said first voltage.

24. The power converter controlling method according to claim 22,

wherein said second load is a motor, and

said power converter controlling method causes said switching power-supply circuit to perform said switching operation according to a command value that is obtained on the basis of:

a deviation of a rotating speed of said motor with respect to its command value; and

said first voltage.

25. The power converter controlling method according to claim 22, which causes said switching power-supply circuit to perform said switching operation according to a command value that is obtained on the basis of:

said first voltage and a second current flowing in said second load.

26. The power converter controlling method according to claim 22, which causes said switching power-supply circuit to perform said switching operation according to a command value that is obtained by subtracting a correction value obtained by multiplying said first voltage and the predetermined value from a command value to said switching operation.