IE51606B1 - Power supply system for a plurality of electronic equipments - Google Patents

Abstract

1. A power distribution system für electronic assemblies (E), this system comprising on the one hand primary supply connected ti an AC network (SR) and including a primary source (SA) which is used for normal operation, and a primary emergency source (SB), and on the other hand a secondary supply including stabilized secondary sources (CA) which are located in said electronic assemblies, characterized in that said primary source (SA) which is used for normal operation is connected in each one of said assemblies (E) to a first group of stabilized secondary sources (CA) and that said primary emergency source (SB) is backed up by a buffer battery (B) and is connected in each one of said assemblies (E) to a second group of stabilized secondary sources (CB).

Description

The invention relates to a power supply system for a plurality of electronic equipments. It applies principally to the electronics, telecommunications and computer industries, and in particular to supplying power to automatic exchanges.

Electronic equipment, which is of ever increasing reliability, generally requires an extremely reliable power supply that is proof against any interruption.

At the same time such power supplies are being required to fit-in easily with different kinds of network for distribu10 ting primary energy, thereby making it possible to reduce the volume and complexity of the equipment in such networks, and to be constituted themselves of a small number of compact and robust components.

In particular, in the case of a power supply system including a primary source powered from a primary network, e.g. conventional 220 volt AC mains, and backed-up by a storage battery, known systems suffer from a drawback that prevents them from meeting the conditions mentioned above.

This is due to the fact that, since the battery is installed as a buffer to take over supplying power the moment there is a mains failure, the power supply system must be capable, on mains being re-established, of supplying the current necessary to recharge the battery in addition to the normal power requirements of the installation.

This requires over-dimensioned means that are complex and voluminous. Indeed, battery-charging requires a very wellregulated power supply, while the electronic units of the - 3 installation are generally powered via secondary sources such as inverters or other converters which incorporate their own regulation and therefore do not require the primary source that powers them to be regulated also. This type of installation thus includes a primary source that is regulated over its entire power range, even though such regulation is only actually required by the connection of the battery as a buffer. Such a connection needs to be regulated both for the battery charging per se. and to ensure a proper switch over from the primary source to the battery, since the switch over is normally effected by means of diodes which necessitate accurate adjustment of the potential difference between the outputs from the primary source itself and from the battery.

Preferred embodiments of the invention meet the requirements mentioned above, while avoiding the drawbacks that have just been described.

The present invention provides a power supply system for a plurality of electronic equipments, the system being constituted by a primary power supply connected to AC mains and by a secondary power supply located in said electronic equipments, said primary power supply comprising a primary source for normal operation and a primary source for back-up operation, and said secondary power supply comprising regulated secondary sources, wherein said primary source for normal operation is connected in each of said equipments to a first group of regulated secondary sources, and wherein said backup primary source is backed-up by a buffer battery and is connected in each of said equipments to a second group of regulated secondary sources.

Preferably the normal operation primary source is constituted by non-regulated rectifier circuits, does not include SI 606 - 4 its own back-up, and supplies no power in the event of a mains failure.

At the same time, the backed-up primary source preferably includes at least one regulated rectifier circuit dimen5 sioned to be capable of simultaneously providing charging current to said battery and no-load stand-by current to said second group of secondary sources.

Various applications of the invention are described with reference to the accompanying drawings which show: Figure 1, power supply to a plurality of electronic equipments via DC-DC converters; Figure 2, parallel connection of normal and emergency mode converters in a duplicated power supply; Figure 3, power supply to a plurality of electronic equipments via DC-DC and AC-DC converters; Figure 4, un-interruptable AC power supply to apparatus . via inverters; Figure 5, a variant of Figure 4, in which non-backedup power supply is taken directly from mains; Figure 6, power supply to a plurality of electronic equipments with redundant secondary sources; and Figure 7, a plurality of redundant electronic equipments powered by backed-up and by non»»baoked-up sources.

A first application of the invention concerns supplying power to a DC load from an AC mains (Figure 1). This could be a power supply system for a telephone exchange, for example.

AC mains SR powers two primary sources, a normal primary source SAI and a back-up primary source SB1, each capable of powering the entire exchange. As is explained below, in normal - 5operation the normal source SAI powers the exchange, while the back-up source SBl operates at low power. The normal source SAI does not include its own back-up, while the backup source SBl does include a battery buffer.

The source SAI comprises 1 to n filtered rectifier circuits of conventional type (RD1 to RDn), e.g. using a diode bridge followed by a capacitor/inductor filter.

The backed-up source SBl comprises 1 to i regulated rectifier circuits (RRI to RRi) backed-up by respective buffermounted batteries (Bl to Bi).

The exchange comprises 1 to k electronic equipments (El to Ek), each occupying one rack for example, and each constituting a load represented in the figure by a resistance RC.

The secondary power supply is constituted by DC-DC converters. This power supply may be duplicated or redundant.

In this application, it will be taken to be duplicated. Each electronic equipment has 1 to 3 converters CA1 to CAq used in normal operation, and 1 to 3 back-up converters CB1 to CBq, each coupled with a corresponding one of the normal converters CA.

The normal converters CA are powered by the normal source SAI, and the back-up converters CB are powered by the back-up source SBl.

The sources SAI and SBl are each capable of powering in parallel 1 to k exchange equipments El to Ek.

The system operates as follows: - Normal operation : power is supplied via a chain comprising the mains SR, the normal primary source SAI, and the normal secondary sources CA1 to CAq. The back-up secondary sources CB1 to CBq are powered-up, but no current is - 6 being drawn from them. They are thus on stand-by ready to take over from the normal secondary sources CA in the event of a failure (Figure 2).

- Mains failure : power is supplied from the batteries 5 B via the back-up secondary sources CB.

- Mains re-established : return to normal operation, except that the back-up primary source SB1 supplies recharging current to the batteries via its regulated rectifier circuits RR.

- Failure of a converter CAj : the converter CBj automatically takes over.

The system uses a regulated power supply of low power on the primary side, which is used only to maintain battery charge and to power the back-up secondary sources while they are on stand-by.

In the event of the last kind of failure mentioned, power will automatically be drawn from the battery if the power required by the converter CB exceeds the power available at the outputs of the regulated rectifier circuits RR.

Figure 3 shows a varient of the above case, likewise for providing DC power to a plurality of electronic equipments A non-backed-up primary source SA2 provides AC via one or more transformers TRp. (In this and the following figures only one electronic equipment is shown. Naturally, as in the previous case, there may be an arbitrary number of them.).

Transformers TRp may serve solely as isolators, or they may also serve to change voltage. In this case, the normal converters CAt of the secondary source are AC-DC converters.

Naturally, in order to use only a single type of con30 verter per electronic equipment, or even throughout the - 7 entire installation, it would be possible to use combined type converters in AC-DC mode for the sources that are powered by SA2, and in DC-DC mode for the back-up sources.

Figure 4 shows an application of the invention to equipments or apparatus requiring a source of uninterrupted AC, e.g. computers.

As in the case of Figure 1, the primary power supply comprises a non-backed-up DC source SA3 together with a DC source SB3 backed-up by a battery Ba. The normal source SA3 is constituted by at least one unregulated filtered rectifier circuit RDa. The back-up source SB3 includes at least one regulated rectifier circuit RRa.

The secondary source is constituted by at least one normal inverter QA powered by the normal source SA3, and at least one back-up inverter OB powered by the back-up source SB3.

The apparatus is powered by one or other of the inverters via a switch-over device C which may be static or electromagnetic. Switching is controlled by a test line t connected to the inverter QA : the switch changes over from input A to input B when the output voltage of the inverter QA drops below a first pre-set threshold. It changes back again when the voltage rises and passes a second pre-set threshold.

In a variant of this application shown in Figure 5, the primary power supply for normal operation does not include specific primary source circuits ; mains is used directly as the non-backed-up primary source, and is connected directly to an isolating and voltage-changing transformer located in the equipment EA. The transformer supplies power directly to the apparatus Ap via the switch C. The backed-up source and the back-up inverter are the same as for Figure 4. - 8 Figure 6 shows a combined system for electronic equipment including redundant units and secondary sources that are redundant, but not duplicated. In this figure the system is applied to a variant of the application shown in Figure 1.

Converters CA, CB & CC are of the DC-DC type. The electronic units of the equipment El are divided into two groups G1 & G2 of units of the same type. The group G1 has a duplicated power supply, while the group G2 has a single power supply connected to the backed-up source. For this purpose the regulated rectifier circuits of the backed-up source are more powerful than in the case of Figure 1, in order to provide the current necessary for normal operation of the converter CC.

Figure 7 shows an application of the system shown in Figure 1 to a case where a high degree of security is required for the electronic equipments. The equipment Em includes two groups of units (which may be identical or otherwise), and each group has a duplicated power supply. The security of the power supply is reinforced by the presence of an additional emergency converter CS which is powered by the source SB and which can replace any of converters CA3, CB3, CA4 or CB4 in the event of failure.

Claims (10)

1. A power supply system for a plurality of electronic equipments, the system being constituted by a primary power supply connected to AC mains and by a secondary power supply located in said electronic equipments, said primary power supply comprising a primary source for normal operation and a primary source for back-up operation, and said secondary power supply comprising regulated secondary sources, wherein said primary source for normal operation is connected in each of said equipments to a first group of regulated secondary sources, and wherein said back-up primary source is backedup by a buffer battery and is connected in each of said equipments to a second group of regulated secondary sources.

2. A power supply system according to claim 1, wherein said primary source for normal operation is constituted by non-regulated rectifier circuits.

3. A power supply system according to claim 1 or 2, wherein said primary source for normal operation does not include its own back-up, and supplies no power in the event of a mains failure.

4. A power supply system according to claim 1, wherein the backed-up primary source includes at least one regulated rectifier circuit dimensioned to be capable of simultaneously providing charging current to said battery and no-load stand by current to said second group of secondary sources.

5. A power supply system according to claim 1, wherein said primary source for normal operation is constituted by a transformer and wherein the first group of regulated secondary sources is constituted by AC-DC converters.

6. A power supply system according to any preceding claim, wherein said first and second groups of secondary sources - 10 comprise converters connected via decoupling diodes to the load to be supplied with power.

7. A power supply system according to claim 1, wherein said first and second groups of secondary sources comprise 5 inverters connected to apparatus to be supplied with AC via switch means controlled by the output voltage from the first group inverter.

8. A power supply system according to claim 1, wherein one of the electronic equipments includes units of the same type

9. 10 organized in two groups, the units of one of the groups being supplied with power in parallel by both groups of secondary sources, and wherein the units of the other group are supplied with power only via a secondary source that is connected to the backed-up primary source.

10. 15 9. A power supply system for a plurality of electronic equipments according to claim 1 substantially as herein described with reference to the accompanying drawings.