DIRECT AC POWER CONVERTING APPARATUS

• US 20100246217A1
• Filed: 10/06/2008
• Published: 09/30/2010
• Est. Priority Date: 10/09/2007
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Sakakibara, Kenichi
• Granted Patent: US 8,310,848 B2
• Time in Patent Office: Days
• US Class Current: 363/37
• CPC Class Codes: H02M 1/126 using passive filters
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements

Abstract

A control section controls a current-source converter simultaneously with or prior to conduction of a power supply switch to connect a clamp capacitor and capacitors between a first input line on which a resistor is provided and any one of second and third input lines in parallel with each other. Accordingly, current is transmitted to the clamp capacitor via the resistor when the power supply switch is brought into conduction, which prevents inrush current from flowing to the clamp capacitor. In addition, for example, the capacitors are not charged prior to the clamp capacitor, whereby it is possible to prevent the inrush current from flowing from the capacitors to the clamp capacitor when they are connected in parallel with each other.

Claims

1. A direct AC power converting apparatus, comprising:

first to N-th input lines connected to an N-phase AC power supply;

a power supply switch selecting conduction/nonconduction of said first to N-th input lines;

a positive-side DC power supply line and a negative-side DC power supply line;

a current-source power converter including a plurality of switch devices, converting an AC voltage input from said first to N-th input lines into a square-wave-shape voltage having two potentials by selection operations of said plurality of switch devices to supply said voltage to said positive-side DC power supply line and said negative-side DC power supply line;

a plurality of input capacitors each provided between ones of said first to N-th input lines and functioning as a voltage source;

a first diode connected between said positive-side DC power supply line and said negative-side DC power supply line;

a capacitor connected, between said positive-side DC power supply line and said negative-side DC power supply line, in series with said first diode;

a first resistor provided on said first input line;

a voltage-source power converter converting said DC voltage having two potentials between said positive-side DC power supply line and said negative-side DC power supply line into a square-wave-shape AC voltage and outputting to an inductive multi-phase load; and

a control section controlling the selection operations of said plurality of switch devices and said power supply switch, and controlling the selection operations of said switch devices simultaneously with or prior to conduction of said power supply switch to connect said capacitor and said input capacitor provided between said first input line and said second input line in parallel with each other.

2. The direct AC power converting apparatus according to claim 1, further comprising:

a reactor connected in series with said first resistor on said first input line.

3. The direct AC power converting apparatus according to claim 1, further comprising:

a reactor connected in parallel with said first resistor.

4. The direct AC power converting apparatus according to claim 1, further comprising:

second to N-th resistors provided on said second to N-th input lines, respectively.

5. The direct AC power converting apparatus according to claim 4, further comprising:

first to N-th reactors connected in series with said first to N-th resistors on said first to N-th input lines, respectively.

6. The direct AC power converting apparatus according to claim 4, further comprising:

first to N-th reactors connected in parallel with said first to N-th resistors, respectively.

7. The direct AC power converting apparatus according to claim 1, wherein said positive-side DC power supply line is applied with a potential higher than that of said negative-side DC power supply line, and said first diode is provided on said second output line side with respect to said capacitor,

the direct AC power converting apparatus further comprising:

a second capacitor connected in series with said capacitor between said positive-side DC power supply line and said negative-side DC power supply line, and connected between said first diode and said second output line;

a second diode having an anode connected between said first diode and said second capacitor and a cathode connected to said positive-side DC power supply line; and

a fourth diode having an anode connected to said negative-side DC power supply line and a cathode connected between said second diode and said capacitor.

8. The direct AC power converting apparatus according to claim 2, wherein said positive-side DC power supply line is applied with a potential higher than that of said negative-side DC power supply line, and said first diode is provided on said second output line side with respect to said capacitor,

the direct AC power converting apparatus further comprising:

a second capacitor connected in series with said capacitor between said positive-side DC power supply line and said negative-side DC power supply line, and connected between said first diode and said second output line;

a second diode having an anode connected between said first diode and said second capacitor and a cathode connected to said positive-side DC power supply line; and

a fourth diode having an anode connected to said negative-side DC power supply line and a cathode connected between said second diode and said capacitor.

9. The direct AC power converting apparatus according to claim 3, wherein said positive-side DC power supply line is applied with a potential higher than that of said negative-side DC power supply line, and said first diode is provided on said second output line side with respect to said capacitor,

the direct AC power converting apparatus further comprising:

a second capacitor connected in series with said capacitor between said positive-side DC power supply line and said negative-side DC power supply line, and connected between said first diode and said second output line;

a second diode having an anode connected between said first diode and said second capacitor and a cathode connected to said positive-side DC power supply line; and

a fourth diode having an anode connected to said negative-side DC power supply line and a cathode connected between said second diode and said capacitor.

10. The direct AC power converting apparatus according to claim 4, wherein said positive-side DC power supply line is applied with a potential higher than that of said negative-side DC power supply line, and said first diode is provided on said second output line side with respect to said capacitor,

the direct AC power converting apparatus further comprising:

a second capacitor connected in series with said capacitor between said positive-side DC power supply line and said negative-side DC power supply line, and connected between said first diode and said second output line;

a second diode having an anode connected between said first diode and said second capacitor and a cathode connected to said positive-side DC power supply line; and

a fourth diode having an anode connected to said negative-side DC power supply line and a cathode connected between said second diode and said capacitor.

11. The direct AC power converting apparatus according to claim 5, wherein said positive-side DC power supply line is applied with a potential higher than that of said negative-side DC power supply line, and said first diode is provided on said second output line side with respect to said capacitor,

the direct AC power converting apparatus further comprising:

a second capacitor connected in series with said capacitor between said positive-side DC power supply line and said negative-side DC power supply line, and connected between said first diode and said second output line;

a second diode having an anode connected between said first diode and said second capacitor and a cathode connected to said positive-side DC power supply line; and

a fourth diode having an anode connected to said negative-side DC power supply line and a cathode connected between said second diode and said capacitor.

12. The direct AC power converting apparatus according to claim 6, wherein said positive-side DC power supply line is applied with a potential higher than that of said negative-side DC power supply line, and said first diode is provided on said second output line side with respect to said capacitor,

the direct AC power converting apparatus further comprising:

a second capacitor connected in series with said capacitor between said positive-side DC power supply line and said negative-side DC power supply line, and connected between said first diode and said second output line;

a second diode having an anode connected between said first diode and said second capacitor and a cathode connected to said positive-side DC power supply line; and

a fourth diode having an anode connected to said negative-side DC power supply line and a cathode connected between said second diode and said capacitor.