JPH0236738A - Uninterruptible power system - Google Patents

Abstract

PURPOSE:To facilitate maintenance and to improve the reliability by connecting a DC motor generator to a DC output where a rectifier and a battery are connected in parallel and connecting the output of a static power converter to the output of the DC motor generator. CONSTITUTION:A rectifier 2 and a battery 3 receiving power from a commercial power source 1 are connected in parallel and a DC motor generator 6 is connected to the DC output thereof. A static power converter 10 comprising a rectifier 7, a constant frequency voltage power source comprising an inverter, and a rectifier 9 is connected to the commercial power source 1. These two systems are connected in parallel through anti-counterflow rectifiers 11, 12. DC power is fed to the most important DC load 13 through the anti-counterflow rectifier 13. In order to supply power to an AC load which is important next to the DC load 13, an AC generator 17 and a switchgear 18 are coupled directly with a DC motor 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an uninterruptible power supply device for supplying direct current to loads in various factories without momentary interruption.

[Conventional technology]

For example, in a flat glass manufacturing factory, if the rotational speed of the electric motor that drives the conveyor rolls used to pull out sheet glass from a glass melting kiln changes, the sheet glass may break, and even momentary power outages can cause problems such as sheet glass wrapping around the rolls. In the worst case scenario, there is a risk that the operation of the kiln may have to be stopped, so an uninterruptible power supply with no instantaneous power interruption and less voltage fluctuation is required.

Conventionally, such uninterruptible power supplies include those in which a DC motor generator and a battery are connected in parallel, and those in which a static power converter and a battery are connected in parallel.

[Problem that the invention seeks to solve]

However, in the case of the former type of conventional uninterruptible power supply, when the motor generator is one set, when replacing the bearing,
Production had to be stopped when brushes were replaced or when they broke down. If two motor generators are installed, this problem will not occur, but since both are DC rotating machines, maintenance costs and man-hours will double, and if they are connected directly in parallel, the output of the generator will decrease. Since there are slight differences in the voltage, which causes voltage fluctuations, a static device such as a voltage regulator is required.

The latter has drawbacks such as being vulnerable to disturbances such as surges and making it difficult to diagnose the deterioration tendency of individual elements compared to rotating machines.

The present invention has been made in view of these points, and an object of the present invention is to provide an uninterruptible power supply device that is easy to maintain and has high reliability.

[Means to solve the problem]

The present invention is an uninterruptible power supply system in which a DC motor generator is connected to the DC output of a rectifier and a battery connected in parallel that receive commercial power as input, and the commercial power is exchanged to DC using a static power exchanger with a rectifying function. and is characterized in that it is connected in parallel to the output side of the DC motor generator via a backflow prevention rectifier.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of the present invention. In one system, a rectifier 2 and a battery 3, which receive a commercial power source 1 as input, are connected in parallel, and a DC motor 4 and a battery 3 are connected in parallel on the DC output side. A DC motor generator 6 consisting of a DC generator 5 directly connected to the DC motor generator 4 is connected.

The other system has commercial power supply 1, rectifier 7, and inverter 8.
A static power converter 10 is connected, which is composed of a constant frequency constant voltage power supply (CVCF) such as a constant frequency constant voltage power supply (CVCF), and a rectifier 9 which has a voltage adjustment function and is made of, for example, Cyrisk.

The uninterruptible power supply of the present invention is a system in which these two systems are connected in parallel via a backflow prevention rectifier 11.12, which supplies DC power to the most important DC load 13-1.3. In the other system, the battery 3 is connected to the output side of the rectifier 7, and in order to keep the voltage of the DC TX source constant, this voltage is fed back to make the deviation from the set value zero. A control circuit 14 that generates such a signal is provided to control the gate of the thyristor as the rectifier 9.

In addition, in preparation for a prolonged power outage of the commercial power supply, emergency power generation equipment 15 such as a diesel generator is installed.

On the other hand, in order to supply power to the AC loads 16--16, which are the second most important after the DC loads 13--13, an AC generator 17 and a switching switch 18 directly connected to the DC motor 4 are provided.

Next, the operation of this embodiment will be explained.

(Normal Time) In one system, a DC motor 4 is driven by a DC voltage inputted from a commercial power supply 1 and rectified by a rectifier 2, and a DC generator 5 directly connected to the DC motor 4 generates a DC voltage.

In the other system, the commercial type Ml is converted to DC voltage by a rectifier 7, converted to AC voltage by an inverter 8, and converted again to DC voltage by a rectifier 9.

The voltages of the two systems are adjusted by a rectifier 9, and DC power is supplied to the DC loads 13 through rectifiers 11 and 12 for backflow prevention, with each of them bearing approximately 50% of the load. .

(During a power outage) In the event of a power outage of the commercial power supply 1, one system from the battery 3 is connected to the battery 3 - DC motor generator 6 -> backflow prevention rectifier 1.
In route 1, the other system is a route from battery 3 to inverter 8 to rectifier 9 to backflow prevention rectifier 12, and each electric circuit is formed without momentary interruption, and the DC load can continue to operate.

Generally, commercial power outages are extremely short and batteries can provide sufficient power, but if the battery capacity is exceeded, for example 30
In the event of a power outage lasting longer than 1 minute, backup will be provided by the emergency power generation facility 15.

(During equipment failure or repair) When replacing the bearings of the motor generator, replacing the brush, or when the rectifier 2 breaks down, disconnect it from the electrical circuit using the front and rear switches (not shown) and perform restoration or repair work. At the same time, power is supplied to the DC load 13 through the path of commercial power supply 1 → static power converter 10 → backflow prevention rectifier 12.

Even if there is a power outage in this state, power is supplied to the DC loads 13 through the path of battery 3 -> inverter 8 = rectifier 9 - backflow prevention rectifier 12 without any interruption.

In addition, if a part of the static power converter breaks down due to lightning surges, element deterioration, etc., disconnect it from the electrical circuit using switches before and after the faulty part (not shown), perform restoration or repair work, and Electric power is supplied to the load 13 - 13 through a path of commercial power supply 1 -> rectifier 2 - DC motor generator 6 - backflow prevention rectifier 11 .

Even if there is a power outage in this state, the DC load 13-13 is connected to the battery 3 - DC motor generator 6 - backflow prevention rectifier 11.
electricity is supplied without interruption.

(AC load) On the other hand, AC load 16 has the second highest importance after DC load.
-16, AC power is normally supplied through a path of commercial power supply 1 - rectifier 2 - DC motor 4 - AC generator 17 -> switching switch 18 .

During a power outage, battery 3 - DC motor 4 = AC generator 1
Power is supplied without momentary interruption through the route 7→switch switch 18.

If the output voltage of the AC generator 17 becomes zero or decreases when the DC motor 4, AC generator, etc. breaks down or is repaired, the drop in output voltage is detected by an undefined voltage relay (not shown) and the switch is opened/closed. Switch the power supply 18 to commercial power supply 1.
Electric power is supplied through the path of - rectifier 7 - inverter 8 → switching switch 18.

In this case, a slight momentary power outage occurs, but the duration is, for example, 10
The influence on the AC load 16-16 can be suppressed as much as possible by setting it to 0 m5ec or less.

Although the present invention has been described above using preferred embodiments, the present invention is not limited to these embodiments, and various applications are possible.

Even if the power converter has only the rectifier 9 having a voltage regulator function, it has the effect of increasing reliability and making maintenance easy, but as in the embodiment, it has the rectifier 7 and the inverter 8. When combined with CVCF, battery 3
This is even more preferable because it enables backup and supply to an AC load.

The load distribution between the DC output of the DC motor generator 6 and the DC output of the rectifier 9 can be arbitrarily done by adjusting the field of the DC generator or by changing the respective output voltages in the control circuit 14. As in the example, it is preferable to keep the output voltages approximately the same and share the load by 50% because voltage fluctuations can be minimized when the load is shared by only one system due to equipment failure or the like.

Regarding AC loads, if all important loads are driven by DC, the alternating current generator 17 becomes unnecessary because normal AC loads can be connected directly to the commercial power source.

[Effects of the Invention] As explained above, the uninterruptible power supply of the present invention not only secures direct current power without instantaneous power outage in case of commercial power outage, failure of various equipment, or repairs, but also provides protection against lightning, lightning, etc. DC motor generators compensate for the drawbacks of static power converters when it comes to disturbances such as surges caused by circuit opening and closing, and in terms of maintenance, scheduled maintenance such as brush replacement and bearing replacement can be performed periodically. Since it is a single set, it has the advantage of reducing costs and man-hours, and can be effectively employed in various applications other than plate glass manufacturing, such as steel manufacturing and paper manufacturing.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of the present invention. 1-11 Commercial power t* 2-m-Rectifier 3--Bassoterie-6--DC motor generator 10--Static power converter 11.12-11 Backflow prevention rectifier

Claims (1)

[Claims] A DC motor-generator is connected to the DC output of a rectifier and a battery connected in parallel with the commercial power input, and the commercial power is converted to DC by a static power converter, and a reverse current is supplied to the output side of the DC motor-generator. An uninterruptible power supply characterized by being connected in parallel via a preventive rectifier.