DE102007050455B4 - Uninterruptible power supply - Google Patents

Abstract

Uninterruptible power supply comprising:
a plurality of battery cells connected in series,
- means for tapping a first voltage from a first number of cells associated with a first rectifier or via a first load rail;
- means for tapping a second voltage from a second number of cells, the number of which is less than that of the first number of cells communicating with a second rectifier, or via a second load rail;
- A switching element (K1), which switches when falling below a predetermined voltage threshold by discharging the first number of cells, the first number of cells to the second, or via the second load rail, characterized in that the first number of cells is designed in that nominally 60V can be tapped and tapped at the second number of nominally 48V cells, the switching element being driven by a threshold switch.

Description

The invention relates to an uninterruptible power supply, which is used in particular for telecommunications equipment.

Field of the invention

Telecommunications systems are often secured by emergency power supplies or uninterruptible power supplies (UGV). These ensure that even in the event of a power failure, operation is secured for a certain period of time, or a safe shutdown of the system becomes possible.

In the publication DE 196 48 339 A1 a new electricity supply system, in particular for telecommunications equipment, which consists of a distribution board ( 2 ), Rectifiers ( 3 . 3 ' ), a DC / battery distributor ( 4 ) and optionally from a counter cell module ( 5 ), which are connected via control lines with a sequence control circuit ( 6 The article by Venekamp Hans Peter: "Telephone Power System Circuitry" explains the concept of power supplies to telecommunications equipment, the use of DC / DC converters in combination with rectifiers to standardize the power supply to all installations and the Basic battery introduced as a common battery for all consumers.

The GB 1 559 782 A discloses a power supply having a particular cell structure.

For the uninterrupted supply of telecommunication equipment with DC voltage (60V), a rectifier (60V) and a battery (60V) are required. If a new technology with 48V and an existing technology with 60V is to be supplied at one location, a new rectifier system and a new 48V battery must be set up for the 48V technology. The rectifier system can be adjusted by the current modular design relatively well to the initial / expansion needs. This is already much more difficult with the battery, since size, number and age have to be matched. A high fluctuation rate with small payback rates is very likely. Furthermore, it can also easily lead to space problems (production area).

Overview of the invention

Object of the present invention is to use the existing 60V battery for the 48V consumers with or to increase the battery capacity, the common performance (48V and 60V) in a battery (voltage) as the basis.

This object is achieved by an invention having the features of the independent claim. Advantageous embodiments and further developments are the subject of the dependent claims.

It is built to supply the 48V consumers a 48V rectifier system. The battery line (s) of the 48V system is connected via a decoupling diode to a tap between the 22nd and 23rd cell of the 60V battery. The 48V system operates in "no battery" mode and usually has nothing to do with battery charging. In every operating state, the 48V system is decoupled from the 60V section. The charge of the battery is preferably from the 60V rectifier group.

At the beginning of a power failure, the consumer rail will supply approximately 42-48V depending on the battery's discharge load. After a short time, a contactor switches the voltage, which has now fallen to just below 60V (30th cell), to the 48V consumer bus without interruption.

The tap valve should be designed redundantly according to the availability requirement of the UGV. After mains return, the contactor disconnects the 48V load bus again from the 30th cell of the 60V battery. The 48V rectifiers take over the supply of consumers again. Since the connection to the tap on the 22nd cell always remains (only decoupled via diodes), there is no interruption in the supply of the telecommunication devices. Only the permitted voltage limits are exhausted.

As part of an operational test, the voltage curves were measured on the 48V rail. From this is the in 5 illustrated modified "Umschalteinrichtung / field for a combined 48V / 60V UGV system" has been developed. In order to comply with the voltage limits required by ETSI-EN 300 132-2, an additional 3 reduction diodes are required on the 30th cell. In exceptional cases, local conditions may require one to two additional reduction diodes.

A voltage monitoring relay detects a power failure by dropping the battery voltage. _Depending on the voltage, the 48V rail is now switched to the 30th cell _without interruption (U _{batt (30 cells)} = 59.5V). The _switch- back after mains return is also voltage-dependent → U _{batt (30 cells)} = 60.0 ... 60.5V).

This retrofit has created a new circuit variant that allows the connection of 60V and 48V consumers to one battery.

With this concept, it is cost-neutral in which timeframe the communication technology is switched from 60V to 48V. In any case, the energy is provided from a battery. Apart from the normal extra demand, the energy requirement swings from the 60V to the 48V side. Furthermore, there is no need for additional production space for batteries. Initial and follow-up investment of a 48V battery is eliminated. In case of a technical change (supply from 60V to 48V or vice versa) no constant adjustment of the battery sizes is required (60V battery smaller, 48V battery larger)

Depending on the shift of the load, the clocked rectifiers (after voltage switching) can be converted from the 60V group to the 48V group in newer systems of the same manufacturer.

The total battery capacity (total 60V and 48V) is lower per site due to reserves of grading sizes of two on one battery group (only one construction-related reserve).

The full energy content of the 60V battery can also be used for 48V consumers. Battery replacement due to the higher power requirements of the 48V devices thus accounts for the same power consumption voltage transient solutions that bring additional power losses, eliminated.

It can already be seen today that the future for telecommunication equipment is 48V. The first 48V systems are or are already set up as secondary systems in some operating points.

Since the changeover is not sudden, but creeping, it can be said that in the next 10 Years (or even earlier) in all operating points 48V is needed, either in addition to the expiring 60V or even only 48V. Should a complete changeover be completed within a few years (or even shorter), the double-use 60V battery can be easily converted into a 48V battery by dismantling six cells (economic use is required) and the "6048 switching device" can be used again be used.

The design and dimensioning, based on standard sizes of contactors and diodes, must be discussed with the manufacturers of rectifier systems. The concept is 200A for small and medium-sized operating points in a wall-mounted housing and 1000A (cascadable) for large operating points in the cabinet.

Since the non-procurement costs of the 48V battery are eliminated in the first step by the procurement costs of this new facility, the actual saving begins only with the first necessary extension / replacement of the 48V battery by additional demand applications. The whole thing is particularly saving when changing the technology supply from 60V to 48V. The required overall performance of the operation remains the same or decreases due to new technology. The required battery power is available and is taken from the one battery depending on the required need of both power supply types.

With this flexible design of the UGV, complete retrofitting of telecommunications equipment can be considerably extended in terms of time.

list of figures

• 1 den funktionellen Aufbau einer 48/60V UGV Anlage, einer Gleichrichterbaugruppe für 60V und einer Gleichrichtergruppe für 48V, sowie einem Schalter, der entsprechend umschaltet;
• 2 den Verlauf der Entladespannung einer Bleibatteriezelle;
• 3 die Spannungsgrenzen auf der 48V Schiene;
• 4 die Spannungskurven bei Netzausfall ;
• 5 einen detaillierten Schaltungsaufbau.

In the following the figures are described to which the following detailed description refers. It shows:

• 1 the functional design of a 48 / 60V UGV system, a rectifier assembly for 60V and a rectifier group for 48V, as well as a switch that switches accordingly;
• 2 the course of the discharge voltage of a lead-acid battery cell;
• 3 the voltage limits on the 48V rail;
• 4 the voltage curves in case of power failure;
• 5 a detailed circuit structure.

Detailed description of the invention:

Of the 1 Refer to a rectifier assembly for 60V operation with the associated 60V battery ( 30 Cells) is used and which derives its voltage from the 30th cell. On the rectifier group for the 48V voltage, the 22nd cell of the battery is switched on via a decoupling. It is understood that the selection is not limited to the 22 or 30 cell. Depending on the voltage supplied by the batteries and the areas in which the rectifiers operate, other layouts may be chosen for the connections. However, the division into 22 and 30 cells is possible in many telecommunication systems. However, a limitation on this is not intended.

Furthermore, the circuit has a switch (or contactor), which switches when falling below a predetermined voltage (in the preferred embodiment of 1.9 V / cell) to also switch the residual voltage of the 30 cells to the 48V power rail. The 5 shows the circuit of the contactor in a greater degree of detail. The contactor ( K1 ) is controlled by a threshold switch / relay which switches the contactor when the voltage falls below a predefined threshold.

The fuses protect the diodes and other components located behind the fuses. The diodes are used for decoupling and also have a reduction function in order to comply with the voltage limits required by ETSI-EN 300 132-2 (V1-V5). These diode cascades thus serve to remain in the voltage range or working range of the rectifier. The 5 further shows that the batteries can also be connected in parallel to achieve a higher performance. These are the diodes V1 and V2 provided, which are additionally secured by fuses. The diodes usually generate a voltage drop of 0.8V to 1V.

The 3 shows the calculation of the upper and lower voltage limits. Where the 22 Cells are multiplied by the lower voltage U _min = 22 * 1.91V, and then the drop of 1.5V of the diode is taken into account. The further calculations are self-explanatory.

The 4 shows the voltage during a power failure and a later return of the network. It can be seen clearly that the voltage of the 48V range rises significantly below the voltage of about 59V, since the contactor is then switched to switch the residual voltage of the 30-cell battery to the 48V range.

After e.g. approx. 5 minutes, the mains voltage supply is restored, which causes the contactor to switch back to voltage-controlled. The charge of the battery is introduced from the 60V rectifier group.

Claims (11)

An uninterruptible power supply comprising: - a plurality of battery cells connected in series, - means for tapping a first voltage from a first number of cells in communication with a first rectifier or via a first load rail; - means for tapping a second voltage from a second number of cells, the number of which is less than that of the first number of cells communicating with a second rectifier, or via a second load rail; - A switching element (K1), which switches when falling below a predetermined voltage threshold by discharging the first number of cells, the first number of cells to the second, or via the second load rail, characterized in that the first number of cells is designed in that nominally 60V can be tapped and tapped at the second number of nominally 48V cells, the switching element being driven by a threshold switch. Uninterruptible power supply according to the preceding claim, wherein the rectifier / consumer rails have a different working range, and the predetermined voltage threshold determines the falling below the working range of the first load rail. Uninterruptible power supply after Claim 1 wherein the output of the first rectifier is nominally 60V and that of the second rectifier is nominally 48V. Uninterruptible power supply according to the preceding claim, wherein the working range of the first rectifier / first load rail is in the range of about 50-72 volts and the working range of the second rectifier is in the range of about 40.5-57 volts. Uninterruptible power supply according to the preceding claim, wherein the switching element is designed so that the switching takes place when falling below about 60V. Uninterruptible power supply according to one of the preceding two claims, wherein at least one diode for reducing the voltage between the cells and the rectifier is arranged in order to maintain the working range of the load voltages. Uninterruptible power supply after Claim 1 , wherein the threshold switch turns on when falling below about 59.5 volts, so that the designed as a contactor switching element switches, and off at about 60V, so that the contactor is opened. The uninterruptible power supply of any of the preceding claims, wherein the first number of cells is 30 and the second number of cells is 22. Uninterruptible power supply according to one of the preceding claims, wherein additional cells are also arranged in parallel, so that a parallel tap takes place. Uninterruptible power supply according to one of the preceding claims, wherein fuses are arranged between the rectifier / load bars and the cells. Uninterruptible power supply according to one of the preceding claims, wherein means are provided to charge all cells.

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