Uninterruptible power supply device

Patent metadata

Field	Value
Publication number	US-10756567-B2
Application number	US-201515772163-A
Country	US
Kind code	B2
Filing date	Nov 27, 2015
Priority date	Nov 27, 2015
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

When an abnormality occurs in a first voltage detector (4a), a control circuit (7) in an uninterruptible power supply device controls an inverter (3) in synchronization with an output signal (VI2D) from a second voltage detector (4b) to match a phase of a two-phase AC voltage (VO1, VO2) output from the inverter (3) with a phase of a two-phase AC voltage (VI1, VI2) supplied from a commercial AC power supply (51), and then turns on a semiconductor switch pair (S9, S10) and a bypass switch pair (S7, S8). Accordingly, even when an abnormality occurs in the first voltage detector (4a), the two-phase AC voltage can be supplied to a load (53) without instantaneous interruption.

First claim

The invention claimed is:

1. An uninterruptible power supply device of a two-phase three-wire type, the uninterruptible power supply device comprising:
a converter configured to convert a two-phase AC voltage supplied from a commercial AC power supply into a DC voltage;
an inverter configured to convert the DC voltage generated by the converter or a DC voltage supplied from a power storage device into a two-phase AC voltage, and supply the two-phase AC voltage to a load;
a bypass switch pair having one terminal pair receiving the two-phase AC voltage from the commercial AC power supply and the other terminal pair connected to the load;
a semiconductor switch pair connected in parallel to the bypass switch pair;
a first voltage detector and a second voltage detector each configured to detect an instantaneous value of the two-phase AC voltage from the commercial AC power supply, and generate an output signal indicating a detected value;
an abnormality detector configured to determine whether the first voltage detector normally functions or not, and generate an output signal indicating a determination result; and
a control circuit configured to control the uninterruptible power supply device based on the output signals from the first voltage detector and the second voltage detector and the output signal from the abnormality detector,
i) when the first voltage detector normally functions, the control circuit being configured to:
turn off the bypass switch pair and the semiconductor switch pair; and
control the converter and the inverter in synchronization with the output signal from the first voltage detector,

ii) when an abnormality occurs in the first voltage detector, the control circuit being configured to:
stop an operation of the converter;
control the inverter in synchronization with the output signal from the second voltage detector to convert the DC voltage from the power storage device into a two-phase AC voltage, and to match a phase of the two-phase AC voltage with a phase of the two-phase AC voltage from the commercial AC power supply;
turn on the bypass switch pair and the semiconductor switch pair when a voltage across terminals of the power storage device decreases and reaches a predetermined voltage; and
turn off the semiconductor switch pair after a lapse of a predetermined time period.

2. The uninterruptible power supply device according to claim 1 , wherein
a phase of the output signal from the first voltage detector and a phase of the output signal from the second voltage detector are shifted from each other by a predetermined angle, and
when an abnormality occurs in the first voltage detector, the control circuit is configured to:
generate a monitor signal that is obtained as a result of shifting the phase of the output signal from the second voltage detector by the predetermined angle; and
control the inverter in synchronization with the generated monitor signal to convert the DC voltage from the power storage device into a two-phase AC voltage, and to match a phase of the two-phase AC voltage with the phase of the two-phase AC voltage from the commercial AC power supply.

3. The uninterruptible power supply device according to claim 1 , wherein
when a difference between an effective value of the output signal from the first voltage detector and an effective value of the output signal from the second voltage detector exceeds a predetermined threshold value, the abnormality detector is configured to determine that an abnormality occurs in the first voltage detector.

4. The uninterruptible power supply device according to claim 1 , wherein
based on the output signal from the second voltage detector, the control circuit is configured to determine whether supply of the two-phase AC voltage from the commercial AC power supply is stopped or not, and
when the control circuit determines that supply of the two-phase AC voltage from the commercial AC power supply is stopped, the control circuit is configured to stop the operation of the converter while continuing an operation of the inverter, and convert the DC voltage from the power storage device into a two-phase AC voltage.

5. An uninterruptible power supply device of a two-phase three-wire type, the uninterruptible power supply device comprising:
a converter configured to convert a two-phase AC voltage supplied from a commercial AC power supply into a DC voltage;
an inverter configured to convert the DC voltage generated by the converter or a DC voltage supplied from a power storage device into a two-phase AC voltage, and supply the two-phase AC voltage to a load;
a bypass switch pair having one terminal pair receiving the two-phase AC voltage from the commercial AC power supply and the other terminal pair connected to the load;
a semiconductor switch pair connected in parallel to the bypass switch pair;
a first voltage detector and a second voltage detector each configured to detect an instantaneous value of an AC voltage in one phase of the two-phase AC voltage from the commercial AC power supply, and generate an output signal indicating a detected value;
a third voltage detector configured to detect an instantaneous value of an AC voltage in the other phase of the two-phase AC voltage from the commercial AC power supply, and generate an output signal indicating a detected value; and
an abnormality detector configured to determine whether the first voltage detector normally functions or not, and generate an output signal indicating a determination result; and
a control circuit configured to control the uninterruptible power supply device based on the output signals from the first voltage detector, the second voltage detector and the third voltage detector and the output signal from the abnormality detector,
i) when the first voltage detector normally functions, the control circuit being configured to:
turn off the bypass switch pair and the semiconductor switch pair; and
control the converter and the inverter in synchronization with the output signal from the first voltage detector,

ii) when an abnormality occurs in the first voltage detector, the control circuit being configured to:
stop an operation of the converter;
control the inverter in synchronization with the output signal from the second voltage detector to convert the DC voltage from the power storage device into a two-phase AC voltage, and to match a phase of the two-phase AC voltage with a phase of the two-phase AC voltage from the commercial AC power supply,
turn on the bypass switch pair and the semiconductor switch pair when a voltage across terminals of the power storage device decreases and reaches a predetermined voltage; and
turn off the semiconductor switch pair after a lapse of a predetermined time period.

6. The uninterruptible power supply device according to claim 5 , wherein
when a difference between an effective value of the output signal from the first voltage detector and an effective value of the output signal from the third voltage detector exceeds a predetermined threshold value, the abnormality detector is configured to determine that an abnormality occurs in the first voltage detector.

7. The uninterruptible power supply device according to claim 5 , wherein
based on the output signal from the third voltage detector, the control circuit is configured to determine whether supply of the two-phase AC voltage from the commercial AC power supply is stopped or not, and
when the control circuit determines that supply of the two-phase AC voltage from the commercial AC power supply is stopped, the control circuit is configured to stop the operation of the converter while continuing an operation of the inverter, and converts the DC voltage from the power storage device into a two-phase

Assignees

• Toshiba Mitsubishi Elec Ind

Inventors

• Masunaga Hiroshi
• Yamanishi Akihiro

Classifications

• G06F1/263

  Arrangements for using multiple switchable power supplies, e.g. battery and AC (G06F1/30 takes precedence) · CPC title

• H02J9/062 Primary

  for AC powered loads · CPC title

• H02J7/00

  Circuit arrangements for charging or discharging batteries or for supplying loads from batteries · CPC title

• G06F1/30

  Means for acting in the event of power-supply failure or interruption, e.g. power-supply fluctuations (for resetting only G06F1/24) · CPC title

• H02M3/44

  by combination of static with dynamic converters; by combination of dynamo-electric with other dynamic or static converters · CPC title