Power converter, and inverter device including the power converter

Patent metadata

Field	Value
Publication number	US-9397582-B2
Application number	US-201514638758-A
Country	US
Kind code	B2
Filing date	Mar 4, 2015
Priority date	Oct 2, 2012
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

In a power converter, in a period in which the polarities of output voltage and output current of a power converter differ, a pulse train voltage corresponding to a PWM signal is output by a first switching element and a second switching element being turned off, one element of a first switch element and a second switch element being turned on, and the other element being turned on and off based on an inverted signal of a PWM signal pulse width modulated in accordance with an output voltage command.

First claim

What is claimed is:

1. A power converter, comprising:
first and second switching elements, to each of which a diode is connected in anti-parallel, connected in series to either end of a direct current power supply; and
a bidirectional switch, configured by first and second switch elements being connected in anti-series or anti-parallel, of which one end is connected to a connection point of the first and second switching elements, wherein,
in an operating mode wherein alternating current voltage is output using positive voltage of the direct current power supply input via the first switching element, negative voltage of the direct current power supply input via the second switching element, and voltage input via the bidirectional switch, a period in which polarities of output voltage and output current differ is such that, by the first and second switching elements being turned off, one switch element of the bidirectional switch being turned on in accordance with the polarities of the output voltage and output current, and the other switch element of the bidirectional switch being turned on and off based on an inverted signal of a signal pulse width modulated in accordance with an output voltage command, alternating current voltage obtained by synthesizing voltage input into the other end of the bidirectional switch and a pulse train voltage, which is voltage generated in accordance with the pulse width modulated signal whose amplitude corresponds to the positive voltage or negative voltage of the direct current power supply, is output.

2. The power converter according to claim 1 , wherein the other end of the bidirectional switch is connected to an intermediate potential point of the direct current power supply.

3. An inverter device including the power converter according to claim 2 .

4. The power converter according to claim 1 , wherein the other end of the bidirectional switch is connected to a first end of an alternating current power supply of which a second end is connected to an intermediate potential point of the direct current power supply, and
the sizes of the positive voltage and negative voltage of the direct current power supply, which have the intermediate potential point as a reference, are set to be greater than the amplitude value of the voltage of the alternating current power supply.

5. An inverter device including the power converter according to claim 4 .

6. The power converter according to claim 1 , wherein,
in the operating mode,
the second switching element and second switch element are turned off, the first switching element is turned on and off based on a first signal pulse width modulated in accordance with an output voltage command, and the first switch element is turned on and off based on a signal wherein an idle period is added to an inverted signal of the first signal, in a period in which the polarities of the output voltage and output current are both positive,
the first switching element and first switch element are turned off, the second switching element is turned on and off based on a second signal pulse width modulated in accordance with an output voltage command, and the first switch element is turned on and off based on a signal wherein an idle period is added to an inverted signal of the second signal, in a period in which the polarities of the output voltage and output current are both negative,
the first and second switching elements are turned off, the second switch element is turned on, and the second switch element is turned on and off based on an inverted signal of the first signal, in a period in which the output voltage is of positive polarity and the output current is of negative polarity, and
the first and second switching elements are turned off, the second switch element is turned on, and the first switch element is turned on and off based on an inverted signal of the second signal, in a period in which the output voltage is of negative polarity and the output current is of positive polarity.

7. An inverter device including the power converter according to claim 6 .

8. An inverter device including the power converter according to claim 1 .

9. The power converter according to claim 1 , comprising a control circuit configured to determine whether the polarities of the output voltage and output current differ, and, upon determining that the polarities of the output voltage and output current differ:
control the first and second switching elements to an off-state;
control the one switch element of the bidirectional switch to an on-state in accordance with the polarities of the output voltage and output current; and
turn the other switch element of the bidirectional switch on and off based on the inverted signal of the signal pulse width modulated in accordance with the output voltage command.

10. A power converter, comprising:
first and second switching elements, to each of which a diode is connected in anti-parallel, connected in series to either end of a direct current power supply;
a first bidirectional switch, configured by first and second switch elements being connected in anti-series or anti-parallel, connected between a connection point of the first and second switching elements and the other end of an alternating current power supply of which one end is connected to an intermediate potential point of the direct current power supply; and
a second bidirectional switch, configured by third and fourth switch elements being connected in anti-series or anti-parallel, connected between a connection point of the first and second switching elements and the intermediate potential point of the direct current power supply, wherein
the sizes of the positive voltage and negative voltage of the direct current power supply, which have the intermediate potential point as a reference, are set to be greater than the amplitude value of the voltage of the alternating current power supply, and
in a first operating mode wherein alternating current voltage is output using positive voltage of the direct current power supply input via the first switching element, negative voltage of the direct current power supply input via the second switching element, and intermediate voltage of the direct current power supply input via the second bidirectional switch, a period in which polarities of output voltage and output current differ is such that,
by the first and second switching elements and first bidirectional switch being turned off, one switch element of the second bidirectional switch being turned on in accordance with the polarities of the output voltage and output current, and the other switch element of the second bidirectional switch being turned on and off based on an inverted signal of a signal pulse width modulated in accordance with an output voltage command, alternating current voltage obtained by synthesizing the intermediate voltage of the direct current power supply and a pulse train voltage, which is voltage generated in accordance with the pulse width modulated signal whose amplitude corresponds to the positive voltage or negative voltage of the direct current power supply, is output.

11. The power converter according to claim 10 , wherein,
in the first operating mode,
the second switching element and first bidirectional switch are turned off, the third switch element is turned on, the first switching element is turned on and off based on a first signal pulse width modulated in accordance with an output voltage command, and the fourth switch element is turned on and off based on a signal wherein an idle period is added to an inverted signal of the first signal, in a period in which the polarities of the output voltage and output current are

Assignees

• Fuji Electric Co Ltd

Inventors

• Wang Qichen
• Fujita Satoru

Classifications

• H02M1/12

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

• H02M1/42

  Circuits or arrangements for compensating for or adjusting power factor in converters or inverters · CPC title

• H02M7/487

  Neutral point clamped inverters · CPC title

• H02M1/10

  Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from AC or DC · CPC title

• H02M7/49

  Combination of the output voltage waveforms of a plurality of converters · CPC title