Direct power conversion device and method for controlling direct power conversion device

Patent metadata

Field	Value
Publication number	US-9450502-B2
Application number	US-201314434472-A
Country	US
Kind code	B2
Filing date	Oct 4, 2013
Priority date	Oct 10, 2012
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A first capacitor is provided between a first power supply line and a second power supply line. A charge/discharge circuit includes a second capacitor provided between the first power supply line and the second power supply line and a first switch connected in series to the second capacitor on the side of the first power supply line. A booster circuit boosts the rectified voltage from a diode rectifier to charge the second capacitor. A current blocking part is provided on the first power supply line or the second power supply line between the first capacitor and the second capacitor and blocks flowing of the current from the second capacitor to the first capacitor.

First claim

The invention claimed is:

1. A direct power conversion device, comprising:
a first power supply line;
a second power supply line applied with a potential lower than that of said first power supply line;
a diode rectifier which has an input side connected with a single-phase AC power supply and an output side connected with said first power supply line and said second power supply line, and performs a single-phase full-wave rectification;
a first capacitor provided between said first power supply line and said second power supply line;
a charge/discharge circuit provided between said first power supply line and said second power supply line on a side opposite to said diode rectifier with respect to said first capacitor; and
an inverter inputted with a DC voltage as a voltage between said first power supply line and said second power supply line,
wherein said charge/discharge circuit has
a buffer circuit including a second capacitor provided between said first power supply line and said second power supply line and a first switch connected in series to said second capacitor on a side of said first power supply line between said first power supply line and said second power supply line,
a booster circuit which boosts a rectified voltage from said diode rectifier to charge said second capacitor, and
a current blocking part provided on said first power supply line or said second power supply line between said first capacitor and said second capacitor and blocks flowing of a current from said second capacitor to said first capacitor.

2. The direct power conversion device according to claim 1 , wherein said current blocking part is a diode.

3. The direct power conversion device according to claim 2 , wherein
said booster circuit includes
a second diode provided with an anode and a cathode connected between said first switch and said second capacitor,
a reactor connected between said first power supply line and said anode, and
a second switch connected between said second power supply line and said anode, and
said diode is provided on said first power supply line between said buffer circuit and said booster circuit.

4. The direct power conversion device according to claim 1 , further comprising
a second reactor provided on said first power supply line or said second power supply line between said first capacitor and said diode rectifier.

5. The direct power conversion device according to claim 1 , further comprising
a second reactor provided on said input side of said diode rectifier.

6. The direct power conversion device according to claim 4 , further comprising
a damping resistor connected in parallel to said second reactor.

7. The direct power conversion device according to claim 5 , further comprising
a damping resistor connected in parallel to said second reactor.

8. A method for controlling the direct power conversion device according to claim 4 , the method comprising:
detecting a voltage of said second reactor;
generating a rectification duty as a time ratio where said diode rectifier is conducted;
correcting said rectification duty so as to be reduced more as said voltage is larger, to generate a post-correction rectification duty; and
controlling a zero-phase current of said inverter by use of a zero duty as a time ratio that is set based on said post-correction rectification duty and a discharge duty as a time ratio where said first switch is conducted.

9. The method for controlling the direct power conversion device according to claim 8 , wherein said rectification duty is corrected only in a first period when a cosine value with respect to a value twice as large as a phase angle of an AC waveform outputted by said single-phase AC power supply under grasping the AC waveform as a sine value of the phase angle.

10. A method for controlling the direct power conversion device according to claim 5 , the method comprising:
detecting a voltage of said second reactor;
generating a rectification duty as a time ratio where said diode rectifier is conducted;
correcting said rectification duty so as to be reduced more as said voltage is larger, to generate a post-correction rectification duty; and
controlling a zero-phase current of said inverter by use of a zero duty as a time ratio that is set based on said post-correction rectification duty and a discharge duty as a time ratio where said first switch is conducted.

11. The method for controlling the direct power conversion device according to claim 10 , wherein said rectification duty is corrected only in a first period when a cosine value with respect to a value twice as large as a phase angle of an AC waveform outputted by said single-phase AC power supply under grasping the AC waveform as a sine value of the phase angle.

12. A method for controlling the direct power conversion device according to claim 6 , the method comprising:
detecting a voltage of said second reactor;
generating a rectification duty as a time ratio where said diode rectifier is conducted;
correcting said rectification duty so as to be reduced more as said voltage is larger, to generate a post-correction rectification duty; and
controlling a zero-phase current of said inverter by use of a zero duty as a time ratio that is set based on said post-correction rectification duty and a discharge duty as a time ratio where said first switch is conducted.

13. The method for controlling the direct power conversion device according to claim 12 , wherein said rectification duty is corrected only in a first period when a cosine value with respect to a value twice as large as a phase angle of an AC waveform outputted by said single-phase AC power supply under grasping the AC waveform as a sine value of the phase angle.

14. A method for controlling the direct power conversion device according to claim 7 , the method comprising:
detecting a voltage of said second reactor;
generating a rectification duty as a time ratio where said diode rectifier is conducted;
correcting said rectification duty so as to be reduced more as said voltage is larger, to generate a post-correction rectification duty; and
controlling a zero-phase current of said inverter by use of a zero duty as a time ratio that is set based on said post-correction rectification duty and a discharge duty as a time ratio where said first switch is conducted.

15. The method for controlling the direct power conversion device according to claim 14 , wherein said rectification duty is corrected only in a first period when a cosine value with respect to a value twice as large as a phase angle of an AC waveform outputted by said single-phase AC power supply under grasping the AC waveform as a sine value of the phase angle.

Assignees

• Daikin Ind Ltd

Inventors

• Sakakibara Kenichi

Classifications

• H02M7/5395

  by pulse-width modulation · CPC title

• H02M7/4826

  operating from a resonant DC source, i.e. the DC input voltage varies periodically, e.g. resonant DC-link inverters · CPC title

• H02M5/458

  using semiconductor devices only · CPC title

• H02M1/15 Primary

  using active elements · CPC title

• H02M1/12 Primary

  Arrangements for reducing harmonics from AC input or output · CPC title