JPH05161282A - Uniterruptible power supply unit - Google Patents

Abstract

PURPOSE:To continue the backup operation if AC input power fails and prevent leakage of harmonics current of a load by recognizing a sound converter and changing the operation mode thereof. CONSTITUTION:For example, if a failure is detected in a first power converter CNV1, the defective point is separated by opening the paths of electrical path opening elements SW1 to SW6 and the power source is continuously supplied to the load through a direct transmitting circuit BPS. Meanwhile, the operation mode of a second power converter CNV2 which has operated as an inverter is changed to operate as an active filter. Thereby, a current of the AC input power supply 1 is kept as the sine wave current to control a DC voltage, that is, a battery charging voltage. Moreover, when power failure occurs in the AC input power supply 1, the electrical path opening elements SW1 to SW6 opens to change again the operation mode of the second power converter CNV2 which has operated as the active filter to operate as the inverter in view of continuing supply of power to the load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, an uninterruptible power supply device having a built-in high input power factor converter, and in particular, its operation mode is divided according to an AC input state and a failure state to expand its application range. And an uninterruptible power supply which has improved reliability.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional uninterruptible power supply. A first power converter (hereinafter referred to as a converter) CNV1 including, for example, a high input power factor converter in which a reactor ACL1 and a switching element are configured in a bridge shape is connected to an AC input power supply 1, and its output terminal (DC voltage VDC Is connected to the smoothing capacitor DCC and the battery Batt. Further, a second power converter (hereinafter referred to as a converter) CNV2, which is composed of, for example, a PWM inverter in which a switching element is configured in a bridge shape, is connected, and its AC output is wound via a switch SW5 to a winding T1.
First of a three-winding transformer T1 having 1, T12, T13
Connected to the winding T11.

On the other hand, the AC input power source 1 to the switch SW6
Commercial direct transmission circuit (bypass circuit) BP configured via
S is connected to the second winding T12 of the transformer T1. Also, an AC filter capacitor ACC is connected to the third winding T13 of the transformer T1, and the output terminal O of the uninterruptible power supply is connected.
UT.

In the conventional uninterruptible power supply configured as described above, in a normal operation, the input current of the converter CNV1 is in phase with the AC input power supply 1, that is, a sinusoidal current waveform with a power factor = 1. The battery Batt is charged while the direct current voltage VDC is controlled to a predetermined value.

On the other hand, in the converter CNV2, the DC voltage VDC is input, pulse width modulation (PWM) control is performed so as to obtain a stable sine wave of the same phase as the AC input power source 1, and a leakage inductance L (not shown) of the transformer T1. No.) and an AC filter composed of an AC filter capacitor ACC to remove high frequency components by switching of the converter CNV2 to obtain a sine wave output of a commercial frequency. In addition, at the time of power failure, the converter CN is used with the battery Batt as a DC input.
V2 is operated with constant voltage and constant frequency to obtain a commercial frequency sine wave output, and uninterruptible.

By the way, if the converter CNV1 or the converter CNV2 becomes abnormal (failure), the operations of the CNV1 and CNV2 are stopped, and the switches SW5 and SW6 are closed and the commercial direct transmission circuit BPS is used. To continue load power supply.

[0007]

As described above, the converter CN is
When V1 or the converter CNV2 is out of order, the load feeding is continued through the commercial direct transmission circuit BPS, and the following problems occur. (1) When a power failure occurs, the operation of the converter CNV2 is stopped, so the load power supply is stopped.

(2) Usually, the load of the uninterruptible power supply is a non-linear load such as a computer, and the operation of the converter CNV1 is stopped. Therefore, the harmonic current on the load side directly flows out to the AC input power supply. I will end up.

The object of the present invention is to provide two converters CNV1 even if converter CNV1 or converter CNV2 fails.
1. Except for the worst case where the converter CNV2 fails at the same time, a healthy converter is identified and its operation mode is changed to continue the backup operation at the time of AC input power failure, and to discharge the harmonic current of the load. It is to provide a highly reliable uninterruptible power supply that can prevent the above.

[0010]

In order to achieve the above object, the present invention provides a direct transfer circuit capable of supplying AC power from an AC input power source to a load, and converting the AC power into DC power or a harmonic wave. A first power converter operable as an active filter for removing components, and an active unit electrically connected to the first power converter for converting the DC power into AC power and removing harmonic components. A second power converter that is operable as a filter and supplies AC power to the load, and is connected between the second power converter and the first power converter, and includes the first and second power converters. An uninterruptible power supply including a battery that is charged when the power converter is normal, and a converter mode control circuit that selectively controls an operation mode of each of the first and second power converters, and the alternating current Input power and Serial first between the power converter, the first
Between the second power converter and the second power converter, and between the second power converter and the load, a plurality of circuit-opening elements that are arranged in the direct circuit and can open the corresponding circuit, and the AC input power supply. An AC input monitoring circuit that monitors a power failure state, a converter abnormality detection circuit that detects an abnormality in each of the first and second converters, and outputs a signal according to the detection signal, the AC input monitoring circuit, and Based on the output signal from the converter abnormality detection circuit, the open circuit command is output to any one of the circuit open circuit elements, and the converter mode control circuit on the healthy side of the first and second power converters. And a switch control circuit that outputs an operation command to the.

[0011]

According to the present invention, when an abnormality is detected in the first power converter, the operation is stopped, the circuit-opening element is opened to disconnect the abnormal portion, and the load power is supplied via the direct feed circuit. continue. On the other hand, by changing the operation mode of the second power converter that was operating as an inverter and operating it as an active filter, the harmonic current on the load side is absorbed and the current of the AC input power source is kept sinusoidal, The DC voltage, that is, the battery charging voltage is controlled.

Further, when a power failure occurs in the AC input power supply, the power supply circuit opening element provided between the AC input power supply and the first power converter is opened to operate the second power which is operated as an active filter. By changing the operation mode of the converter again and operating it as an inverter, the DC power of the battery is converted into stable AC power with a constant voltage and a constant frequency, and the load power supply is continued.

When an abnormality is detected in the second power converter, the operation is stopped and the circuit-opening element is opened to disconnect the abnormal portion, and the load power supply is continued via the direct transfer circuit. On the other hand, by changing the operation mode of the first power converter that was operating as a converter and operating it as an active filter, the harmonic current on the load side is absorbed and the AC input power supply current is kept sinusoidal, The voltage, that is, the battery charging voltage is controlled.

Further, when a power failure occurs in the AC input power supply, the first power which is operating as an active filter is opened by opening the circuit opening element disposed between the AC input power supply and the first power converter. By changing the operation mode of the converter again and operating it as an inverter, the DC power of the battery is converted into stable AC power with a constant voltage and a constant frequency, and the load power supply is continued.

From the above, even if the first power converter or the second power converter fails, a sound power converter is identified except for the worst case in which two power converters simultaneously fail. However, since the operation mode can be changed, the backup operation at the time of AC input power failure can be continued and the outflow of the harmonic current of the load can be prevented, resulting in high reliability.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a basic configuration diagram showing a first embodiment of the present invention. The main circuit configuration of the uninterruptible power supply system of this embodiment is as follows. A first converter that is composed of, for example, a high input power factor converter in which a first switch SW1 is connected to an AC input power source 1, a series circuit including a second switch SW2 and a reactor ACL1 and a switching element is configured in a bridge shape. CNV1 and the third switch S
W3, smoothing capacitor DCC, battery Batt, and fourth
DC switch VDC including switch SW4, second converter CNV2 including, for example, a PWM inverter in which switching elements are configured in a bridge shape, and fifth switch S
W5 is connected to the first winding T11 of the transformer T1 having three windings T11, T12, T13, and further connected to the first switch SW1 via the sixth switch SW6.
Of the transformer T1 and an AC filter capacitor ACC is connected to the third winding T13 of the transformer T1 to serve as an output terminal.

The control circuit of the uninterruptible power supply of this embodiment is
It is configured as follows. AC input monitoring circuit 10 for monitoring the state of AC input power supply 1, converter abnormality detection circuit 11 for detecting abnormality of first and second converters CNV1, CNV2, AC input monitoring circuit 10 and converter abnormality A switch control circuit 12 for controlling opening / closing of the first to sixth switches SW1 to SW6 based on an output signal from the detection circuit 11, and a converter mode control circuit 13 for controlling operation modes of the converters CNV1 and CNV2. , The control circuit 14 of the first converter CNV1 and the second converter CNV1.
It is composed of two control circuits 15. The control circuit 14 controls the control circuit unit 2 as an operation mode of the high input power factor converter.
0, a control circuit section 21 as an active filter operation mode, and a control circuit section 22 as a CVCF inverter operation mode. The control circuit 15 is a CVC
The control circuit unit 30 has an F inverter operation mode and the control circuit unit 31 has an active filter operation mode.

Normally, the switches SW1 to SW5 are closed, the converter CNV1 is operated as a high input power factor converter, and its input current is in phase with the AC input power source 1, that is, a sinusoidal current waveform of power factor = 1. The battery BATT is charged while being controlled so that the DC voltage VDC becomes a predetermined value.

On the other hand, the second converter CNV2 is operated as a PWM inverter, and the pulse width modulation (PWM) control is performed so that a DC voltage VDC is input and a stable sine wave in phase with the AC input power source is obtained. In this case, a converter CNV2, that is, a high frequency component due to switching of a PWM inverter is removed by an AC filter composed of a leakage inductance L of a transformer and an AC filter capacitor ACC to obtain a commercial frequency sine wave output. Also, during a power outage,
PWM inverter C with battery Batt as DC input
The NV2 is operated at a constant voltage frequency (CVCF) to obtain a sine wave output at a commercial frequency, thereby making it uninterruptible.

When an abnormality is detected in the high input power factor converter which is the converter CNV1, its operation is stopped and the switches SW1 and SW2 are opened to disconnect the abnormal portion from the uninterruptible power supply, and SW6
Closed the switch of the commercial direct transmission circuit (bypass circuit) B
The load power supply is continued via PS.

On the other hand, by changing the operation mode of the second converter CNV2 that was operating as a PWM inverter and operating it as an active filter, the harmonic current on the load side is absorbed and the AC input current is kept sinusoidal. At the same time, the DC voltage, that is, the charging voltage of the battery Batt is controlled.

Further, when a power failure occurs, the switch SW1 or SW6 is opened, and the operation mode of the converter CNV2, which was operating as an active filter, is changed again to PW.
By operating as an M inverter, the battery B
The DC power of att is converted into stable AC power of constant voltage and constant frequency to continue load power supply.

In this case, in addition to operating the converter CNV2 as a simple active filter, AC voltage adjustment (parallel processing technology) during operation of the commercial direct transmission circuit BPS is possible.

Further, the PWM which is the second converter CNV2
When an abnormality is detected in the inverter, the operation is stopped and the switches SW4 and SW5 are opened to disconnect the abnormal portion from the uninterruptible power supply and the switch SW.
6 is closed to continue load power supply via the commercial direct transmission circuit BPS.

On the other hand, by changing the operation mode of the converter CNV1 that was operating as a high input power factor converter and operating it as an active filter, the harmonic current on the load side is absorbed and the AC input power supply current is made sinusoidal. While maintaining, the DC voltage, that is, the charging voltage of the battery Batt is controlled.

Further, when a power failure occurs, the switch SW1 is opened, the operation mode of the converter CNV1 that was operating as an active filter is changed again, and the converter CNV1 is operated as a PWM inverter, so that the DC power of the battery Batt is kept at a constant voltage. Converts to constant frequency stable AC power and continues load power supply. The two converters CNV1 and CNV2
If both of them become defective at the same time, the load power supply is continued through the commercial direct transmission circuit BPS as in the conventional case.

As described above, according to this embodiment, the following effects can be obtained. In the case of a UPS failure, the load power supply is continued via the commercial direct transmission circuit BPS. However, according to the present invention, as long as the two converters CNV1 and CNV2 do not malfunction at the same time,

(1) When a power failure occurs, either sound converter CNV1 or CNV2 can be operated as CVCF as a PWM inverter, and battery backup can be performed to continue load power supply.

(2) Normally, the load of the uninterruptible power supply is a non-linear load such as a computer. However, by operating either converter CNV1 or CNV2 which is sound as an active filter, the harmonic current on the load side is reduced. It is possible to prevent the AC input power source 1 from flowing out as it is. Therefore, in the first embodiment, a highly reliable uninterruptible power supply device can be obtained.

FIG. 2 is a basic configuration diagram showing a second embodiment of the present invention. In FIG. 2, the switch SW in FIG.
2, SW3, SW4, SW5, fuse FU1, FU
2, FU3, FU4. This is a simplification of the disconnection from the uninterruptible power supply unit in the abnormal state of the two converters CNV1 and CNV2, especially when the switching element of the converter is short-circuited and broken.

In the above-described first embodiment, the switches SW1, SW2, SW3 and SW are used as an example of the electric circuit opening element.
4, SW5 and SW6 have been described as an example, but it goes without saying that at least a part thereof may be replaced with a semiconductor switch, a fuse, or the like.

[0032]

According to the present invention, a sound transducer is identified except for the worst case where two transducers simultaneously fail.
By changing the operation mode, it is possible to provide a highly reliable uninterruptible power supply having a function of continuing the backup operation at the time of AC input power failure and preventing the outflow of the harmonic current of the load.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing a first embodiment of an uninterruptible power supply according to the present invention.

FIG. 2 is a basic configuration diagram showing a second embodiment of the uninterruptible power supply device according to the present invention.

FIG. 3 is a basic configuration diagram showing an example of a conventional uninterruptible power supply device.

[Explanation of symbols]

1 ... AC input power supply, SW1 to SW6 ... Switch, ACL
1 ... Reactor, CNV1, CNV2 ... Power converter, B
att ... battery, DCC ... smoothing capacitor, ACC ...
AC filter capacitor, T1 ... 3-winding transformer, 10
... AC input monitoring circuit, 11 ... Converter abnormality detection circuit, 12
... switch control circuit, 13 ... converter mode control circuit, 1
4 ... Control circuit of power converter CNV1, 15 ... Control circuit of power converter CNV2, 20 ... Control circuit part of high input power factor converter 21, 31, ... Control circuit part of active filter, 22, 30 ... CVCF inverter Control circuit section.

Claims (1)

[Claims] 1. A direct-transfer circuit capable of supplying AC power from an AC input power source to a load, and a first power converter operable as an active filter for converting the AC power into DC power and for removing harmonic components. And an electric filter electrically connected to the first power converter, capable of operating as an active filter for converting the DC power into AC power or removing harmonic components, and supplying AC power to the load. A second power converter; and a battery connected between the second power converter and the first power converter, the battery being charged when the first and second power converters are normal. In the uninterruptible power supply, a converter mode control circuit that selectively controls the operation mode of each of the first and second power converters, between the AC input power supply and the first power converter, and 1st and 2nd power Between the second power converter and the load, between the second power converter and the load, and monitor a power failure state of the AC input power supply, and a plurality of circuit-opening elements that are capable of opening the corresponding circuits. AC input monitoring circuit, converter abnormality detection circuit that detects an abnormality in each of the first and second converters, and outputs a signal corresponding to the detection signal, the AC input monitoring circuit, and converter abnormality detection circuit Based on the output signal from the electric circuit, outputs an opening command to any one of the electric circuit opening elements, and an operation command to the converter mode control circuit on the sound side of the first and second power converters. An uninterruptible power supply including a switch control circuit that outputs a.