JPH05122873A - Uninterruptible power source - Google Patents

Abstract

PURPOSE:To connect an arbitrary energy storage unit of a plurality of energy storage units to any uninterruptible power source by connecting the plurality of energy storage units to a common DC bus through a circuit having first, second semiconductor switches connected in anti-parallel with each other. CONSTITUTION:When a defect occurs in an uninterruptible power source (OPS) 1A, breakers 21A, 24A, 25A are opened. Here, if an energy storage unit 3A is normal, a DC switch 26A is closed, then a DC switch 26B of a UPS 1B is closed, and a first semiconductor switch 28B is closed to connect the unit 3A to the UPS 1B. Accordingly, charging energy from the UPS 1B is supplied to a storage unit 3B, and supplied to the unit 3A in a circuit of the switch 26B, the switch 28B, a DC common bus 27, a diode 29A and the switch 26A. When AC inputs 101A, 101B, 101C are interrupted, switches 28A, 26C are closed to supply energy of the unit 3A to the UPSes 1B, 1C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply unit in which uninterruptible power supply units each having an energy storage unit such as a storage battery are connected in parallel.

[0002]

2. Description of the Related Art An uninterruptible power supply (hereinafter simply referred to as UPS) is used as a power supply for a critical load such as a computer that is not allowed to have a momentary power failure, and its basic configuration is shown in FIG.
Is shown in. In FIG. 3, the AC input 101 is converted to DC by the forward converter 22 via the circuit breaker 21, and is converted back to AC by the inverse converter 23, and the AC output 102 is obtained through the circuit breaker 24. Meanwhile,
The forward converter 22 serves to store DC energy in the energy storage unit 3 via the circuit breaker 25. Here, the energy storage unit 3 is generally a storage battery. Here, when the AC input 101 fails, the DC power of the energy storage unit 3 is supplied to the inverse converter 23, and the AC output 102 of the UPS 1 can be continuously supplied. The above is the basic UPS configuration and operation.

FIG. 4 is a block diagram showing a conventional example in which two or more UPS units are operated in parallel, and the number of parallel operation units is three. In FIG. 4, the three UPS 1A, 1B, 1C are
The individual operations are the same as described with reference to FIG.

In FIG. 4, the purpose of operating the three UPS's 1A, 1B, 1C in parallel is to maintain the AC output 102 in the remaining two even if one of the three fails. Therefore, it is generally called 2outof3 parallel redundant operation.

[0005]

In FIG. 4, it is assumed that the inverse converter 23A has a failure, for example. At this time, the AC output 102 is continuously supplied from the two UPS1B and UPS1C, and the circuit breakers 21A, 24A and 25A are tripped.

In this state, that is, when a power failure occurs in the AC inputs 101A, 101B, 101C when the UPS 1A is out of order, the two UPSs 1B, 1C receive DC power from their respective energy storage units 3B, 3C, Continue driving.

By the way, the energy storage unit 3 of the UPS 1A
Since A is irrelevant to the UPS1A disorder, he is in a situation where he cannot perform his duties while having sufficient energy.
In addition, there is a situation in which direct current energy cannot be stored in the normal energy storage unit 3A. Particularly, as the UPS 1A, 1B, 1C has a larger capacity, the energy storage units 3A, 3B, 3
Since the scale of C also becomes large, there is a disadvantage that it is uneconomical if the whole UPS 1A becomes useless when a failure occurs in a part of UPS 1A.

In FIG. 5, the energy storage unit 3 is commonly provided for the three power converters 2A, 2B and 2C.
The drawback of this FIG. 5 is that the energy storage unit 3 is always shared, and therefore, when a failure occurs in the energy storage unit 3, or when the energy storage unit 3 is maintained or inspected or parts are replaced, AC input is performed. This is a system having a drawback that the AC output 102 of the UPS system 11 cannot be maintained when a failure (power failure) occurs in 101A, 101B, 101C.

The present invention has been made to solve the above-mentioned drawbacks, and by connecting the arbitrary energy storage unit to any uninterruptible power supply unit, the DC energy of the energy storage unit 3 can be reduced. It is an object of the present invention to provide an uninterruptible power supply capable of supplying power to any UPS and capable of storing energy in any energy storage unit 3.

[0010]

In order to achieve the above object, the present invention uses a forward converter for converting an alternating current supplied from a commercial alternating current power source into a direct current, and a direct current output of the forward converter as an input, A plurality of uninterruptible power supply devices, which are composed of an inverse converter that converts direct current into alternating current, and an energy storage unit that supplies direct current power to the inverse converter through a circuit breaker when the commercial power supply fails, are operated in parallel. In the uninterruptible power supply device, the plurality of energy storage units are connected to a common DC bus through a circuit composed of a first semiconductor switch and a second semiconductor switch which are respectively connected in antiparallel. Is.

[0011]

With the above configuration, if a certain uninterruptible power supply unit fails, the energy storage unit of the uninterruptible power supply unit is normal, and the AC input is normal, the failure unit is not damaged. The second semiconductor switch of the power failure power supply is turned on, and the first semiconductor switch of one of the sound generators is turned on. As a result, in the energy storage unit of the faulty machine, the normal machine forward converter 22 → the healthy machine circuit breaker 25 → the first machine switch 28 of the healthy machine → the DC common bus 27 → the second machine of the faulty machine.
Direct current energy can be stored (charged) through the semiconductor switch 29 of FIG. Further, when the AC input is interrupted while the energy storage unit of the faulty machine is normal, the first semiconductor switch of the uninterruptible power supply of the faulty machine is turned on, and the second semiconductor switch of each sound machine is turned on. When turned on, from the energy storage unit 3 of the faulty machine → first semiconductor switch 28 of the faulty machine → DC common bus 27 → second semiconductor switch 29 of each healthy machine → breaker 25 of each healthy machine
DC energy can be supplied (discharged) to each of the inverse converters 23 of the sound machine via the.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 in which the same parts as those in FIGS. The basic operation of the embodiment of FIG. 1 as an uninterruptible power supply is the same as the conventional operation of FIG. That is, the AC inputs 101A, 101B,
While 101C is normally supplied, circuit breakers 21A, 2
1B, 21C, forward converters 22A, 22B, 22C, inverse converters 23A, 23B, 23C, circuit breakers 24A, 24B,
Parallel operation is performed to obtain the AC output 102 through 24C. In addition, the electric power through the forward conversion units 22A, 22B, 22C also stores DC energy in the energy storage units 3A, 3B, 3C. When the AC inputs 101A, 101B, 101C lose power, DC power is supplied from the energy storage units 3A, 3B, 3C to the inverse converters 23A, 23B, 23C, and the AC output 102 is supplied uninterrupted. In the above process, the DC switches 26A, 26B and 26C are in the OFF state, and the DC common bus 27 has no voltage.

If a failure occurs in the UPS 1A, the circuit breakers 21A, 24A and 25A are opened. next,
If the energy storage unit 3A is healthy, the DC switch 26A
Is turned on, and the UPS machine for charging the energy storage unit 3A is selected. Here, as an example, NO. It is assumed that 2UPS1B is selected. After turning on the DC switch 26A, N
O. 2UPS 1B and energy storage unit 3A are connected to each other. The 2UPS 1B DC switch 26B is turned on, and then the first semiconductor switch 28B is turned on. As a result, the NO. The charging energy from 2UPS1B is N
O. The power is supplied to the energy storage unit 3B for 2UPS 1B and the direct current switch 26B → the first semiconductor switch 28B →
DC common bus 27 → diode 29A → DC switch 2
It is also supplied to the energy storage unit 3A via 6A.

In this state, the AC input 101
When power failure occurs in A, 101B, and 101C, the energy of the energy storage unit 3A is set to NO. By turning on the first semiconductor switch 28A and the DC switch 26C.
2UP1B and NO. Supplied for 3UPS 1C.

FIG. 2 is a block diagram showing another embodiment of the present invention. The difference from FIG. 1 is that the DC switches 26A, 26B, 2
6C is omitted, and the first semiconductor switches 28A, 28B,
And 28C in antiparallel to the second semiconductor switch 2
9a, 29b, 29c are connected.

With this configuration, for example, if a failure occurs in the UPS 1A, the circuit breakers 21A, 24A and 25A are opened as described above. Next, if the energy storage unit 3A is healthy, the second semiconductor switch 2
9a is turned on, and the UPS machine for charging the energy storage unit 3A is selected. Here, as an example, NO. 2 UPS 1B
Shall be selected. After turning on the second semiconductor switch 29a, NO. 2 UPS 1B and energy storage unit 3A
NO. The first semiconductor switch 28B of 2UPS1B is turned on. As a result, the NO. 2 UPS
The charging energy from 1B is NO. The power is supplied to the energy storage unit 3B for the 2UPS 1B and the first semiconductor switch 28B → the DC common bus 27 → the second semiconductor switch 2
It is also supplied to the energy storage unit 3A via 9a.

In this state, the AC input 101
When the power of A, 101B, and 101C is cut off, the energy of the energy storage unit 3A is set to NO. By turning on the first semiconductor switch 28A and the second semiconductor switch 29c. 2UP1B and NO. The same effect as that of the embodiment of FIG. 1 can be obtained by being supplied to 3UPS 1C. In FIG. 1, the first semiconductor switch 28A,
Although 28B and 28C are composed of thyristors, this switch can be composed of mechanical switches as another embodiment.

Further, the first semiconductor switches 28A, 28
B and 28C and diodes 29A and 29B connected in anti-parallel,
The circuit composed of 29C may be configured by a reverse conducting thyristor.

[0019]

As described above, according to the uninterruptible power supply system of the present invention, while maintaining the independence of the UPS which operates the energy storage section of the UPS individually and performs the parallel redundant operation at all times, In the event of a UPS failure, disconnect the energy storage unit,
When the AC input is normal, charge from another healthy UPS,
Further, when the AC input fails, DC energy can be supplied to a healthy UPS, so that the utilization rate can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

FIG. 3 is a configuration diagram for explaining a basic operation of the uninterruptible power supply.

FIG. 4 is a configuration diagram of a conventional uninterruptible power supply device.

FIG. 5 is another configuration diagram of a conventional uninterruptible power supply device.

[Explanation of symbols]

1, 1A, 1B, 1C ... UPS 2, 2A, 2B, 2C ... Power converters 3, 3A, 3B, 3C ... Energy storage units 21, 21A, 21B, 21C ... Circuit breakers 22, 22A, 22B, 22C. Forward converter 23, 23A, 23B, 23C ... Inverse converter 24, 24A, 24B, 24C ... Circuit breaker 25, 25A, 25B, 25C ... Circuit breaker 26A, 26B, 26C ... DC switch 27 ... DC common bus 28A, 28B , 28C ... First semiconductor switches 29A, 29B, 29C ... Diodes 29a, 29b, 29c ... Second semiconductor switches 101, 101A, 101B, 101C ... AC input 102 ... AC output

Claims (4)

[Claims] 1. A forward converter for converting an alternating current supplied from a commercial alternating current power source into a direct current, an inverse converter for converting a direct current into an alternating current by using a direct current output of the forward converter as an input, and a power failure of the commercial power source. In the uninterruptible power supply system in which a plurality of uninterruptible power supply units each including an energy storage unit that supplies DC power to the inverse converter via a circuit breaker are operated in parallel, each of the plurality of energy storage units is anti-parallel. An uninterruptible power supply device characterized in that it is connected to a common DC bus through a circuit composed of a connected first semiconductor switch and a second semiconductor switch. 2. The uninterruptible power supply according to claim 1, wherein the first semiconductor switch is a mechanical switch. 3. The second semiconductor switch includes a diode connected in antiparallel to the first semiconductor switch,
The uninterruptible power supply according to claim 1, wherein the uninterruptible power supply is configured by a mechanical switch connected in series to the anti-parallel circuit. 4. The second semiconductor switch includes a diode connected in antiparallel to the first semiconductor switch,
The uninterruptible power supply according to claim 1, wherein the uninterruptible power supply is configured by a mechanical switch connected in series to the anti-parallel circuit.