WO2010097787A1

WO2010097787A1 - Modular ups system

Info

Publication number: WO2010097787A1
Application number: PCT/IL2009/000210
Authority: WO
Inventors: Eli Steinhorn; Joseph Goren
Original assignee: Gamatronic Electronic Industries Ltd
Current assignee: Gamatronic Electronic Industries Ltd
Priority date: 2009-02-25
Filing date: 2009-02-25
Publication date: 2010-09-02
Anticipated expiration: 2011-08-25

Abstract

A modular UPS (10) includes a rectangular frame (11) having a base portion (12), a top portion (13) and first and second opposing side portions (14, 15). A respective pair of support units (16) for each UPS module (17) is fixedly mounted to respective inner surfaces (23) of the side portions for slidably supporting the respective UPS module. A power and control module (18) is mounted on the base portion for coupling to a mains power supply and at least one heat dissipation unit (20) is mounted in association with the frame. Power and busbars (21) extend vertically on an outer surface of the side portions and are electrically connected to power feed in the power and control module for providing power to the UPS modules without obstructing the heat dissipation unit.

Description

Modular UPS system

FIELD OF THE INVENTION

The present invention relates to modular UPS systems (uninterruptible power supplies).

BACKGROUND OF THE INVENTION Data processing installations often include a large number of computers, peripherals and communications devices that host web sites, and process transactions and communications tasks. These installations are often constructed in a modular fashion, e.g., an installation may include a battery of standardized equipment racks (e.g., 19-inch racks) in which multiple computers and data communications devices, e.g., routers, hubs and the like, may be housed. Similar modular architectures may be used in telecommunications systems.

Typically, it is desirable for such installations to have high availability and reliability, such that, for example, data integrity and/or access is preserved even during disruptive events, such as power failures arising from storms, system overloads or other disturbances. Accordingly, such installations typically are powered by uninterruptible power supplies (UPSs), which can improve power quality and/or provide back up power to computing and communications equipment from an alternative source, such as a battery, generator or fuel cell, when utility power fails or is degraded.

Modular UPS systems have been proposed for such installations. For example, some manufacturers offer rack-mount UPSs that are configured to be mounted in a standard (e.g., 19-inch) equipment rack, and that are hardwired (e.g., using lugs or screw terminals) to provide power interconnections. Some modular designs may include a chassis having a subrack or similar structure configured with a backplane or connector field that mates with power modules that slide into the subrack. U.S. Pat. No. 6,967,283 to Rasmussen et al. describes a system where a plurality of equipment racks has a power input to receive power for equipment contained therein. A power distribution rack provides power to the equipment racks and includes a power distribution panel and a plurality of output power cables. A first end of an output cable is coupled to the power distribution panel and a second end of the output cable has a mating connector that pluggably mates with the power input of an equipment rack. The power cables are run from the power distribution rack to the equipment racks using power cable tracks that are located on roofs of the equipment racks.

US 2007/0217178 discloses a modular uninterruptible power supply (UPS) system includes a plurality of UPS system component modules, each configured to be arranged in at least one equipment rack, each of the UPS system component modules having at least one flexible power cable extending therefrom and having a pluggable first connector at an end thereof. The system also includes a modular power interconnect assembly configured to be attached to at least one equipment rack, the modular power interconnect assembly including a housing, a plurality of bus bars positioned within the housing, and a plurality of second connectors positioned at a face of the housing, electrically connected to the plurality of bus bars and configured to pluggably mate with the first connectors to provide electrical interconnection among the plurality of UPS system component modules. The modules disclosed in US20070217178 are mounted in side-by-side relationship such that the higher the power rating of the UPS, the more modules are required with the consequent increase in floor area required to accommodate the UPS. Since floor space is expensive in terms of real estate, this represents a significant drawback of such a modular approach. It is also known to increase the power rating of a modular UPS by mounting modules one on top of the other. For example, Gamatronic of Jerusalem, Israel produce several on-line double-conversion modular UPS units, wherein modules each rated at 10 KVA are mounted one on top of the other in order to produce a UPS of required power rating. This approach has the advantage that floor area is conserved. However, the height of the rack depends on the number of modules, which in turn depends on the power rating. American Power Conversion Corp. (APC) also provides a modular UPS having modules that are built into a rack of depth of 1.1m and of width approximately equal to 60cm. In any modular rack system, it is necessary to provide a duct that allows power cables to be trunked from one module to another. Conventionally, the ' ducts are provided at the back of the modules, so as to be out of sight. However, this can block air flow which is typically directed from the front of the rack to the back in order to cool the modules and prevent their over-heating. This militates against the use of rear ducting where high power modules are used, since the higher the power rating the more heat they need to dissipate. Moreover, of course, the duct also occupies floor area at the back of the rack. Furthermore, the manner in which the power cables are connected to the UPS modules affects the manner in which UPS modules are added to the stack or interchanged. In the Gamatronic device to which reference has been made, UPS modules are plugged via suitable flexible connectors. This requires that after a UPS module is inserted, the power connection be made manually. Although UPS modules can be inserted when the system is live, i.e. hot-swapped, the need to connect the UPS module manually requires a separate action to in addition to insertion of the UPS module into the rack. Moreover, power cables that are rated at high current capacity are bulky and difficult to bend and maneuver. The previous generation of the Gamatronic modular UPS system allows for connection of up to ten UPS modules each rated at 10 KVA thus having a maximum rating of 100KVA. Assuming a 400V 3 -phase supply, this would imply that phase current is in the order of 250A. Current rating of a cable depends on temperature and cross-sectional area of the cable and the number of strands in the cable, when a multi-strand cable is employed as in flexible cables. According to ISO 10133 and ISO 13297 the required cross-sectional area of cable for withstanding 400 A at 60⁰C is in the order of 180 mm², such that its diameter is over 7.5 mm. If power is increased by a factor of three, then for the same voltage, the current capacity must also be increased by a factor of three and so, too, must the cross-sectional area of the cable. This makes the use of flexible cables increasingly unwieldy as power rating increases since it is very difficult to maneuver a cable over 2cm in diameter.

It would therefore be of benefit to provide a modular UPS system, each of whose modules is rated at a higher power rating than currently available modules, but which avoids the need to provide trunking at the rear of the rack thus allowing an unobstructed path for air-cooling.

It would also be of benefit if the modules were adapted for "hot swapping" thus allowing modules to be added and/or exchanged without the need to shut down power - A - to the system and without the need to effect the power connection manually after insertion of a UPS module.

Moreover, it would be desirable to effect the connection of UPS modules to the power source other than by flexible cables.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an improved modular UPS that addresses the above-mentioned considerations.

This object is realized in accordance with the invention by a modular UPS comprising: a rectangular frame having a base portion, a top portion and first and second side portions on opposite sides of the base portion; a respective pair of support units for each UPS module fixedly mounted to respective inner surfaces of the first and second side portions for slidably supporting the respective UPS module; a power and control module mounted on the base portion for coupling to a mains power supply, at least one heat dissipation unit mounted in association with the frame, and a plurality of power busbars extending vertically on an outer surface of one of said side portions and electrically connected to power feed lines in the power and control module for providing power to the UPS modules without obstructing the heat dissipation units.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a modular UPS having a plurality of UPS modules according to an embodiment of the invention;

Fig. 2 is an enlarged front elevation of a UPS module shown in Fig. 1 showing a detail of an air cooling unit; Fig. 3 is a perspective view showing a detail of a rectangular frame within which

UPS modules may be stacked; Fig. 4 is a perspective view showing a detail of a power and control module from which busbars are fed to UPS modules;

Figs. 5 and 6 are perspective views showing details of internal connections in the power and control module; Fig. 7 is a perspective view showing details of the UPS module; and

Figs. 8 and 9 show details of locking mechanism for securing a UPS module.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring to Figs. 1, 2 and 3, there is shown a modular UPS 10 comprising a rectangular frame 11 having a base portion 12, a top portion 13 and first and second side portions 14 and 15, respectively, on opposite sides of the base portion 12. On inner surfaces of the first and second side portions 14 and 15 there are fixedly mounted respective pairs of support units 16 for slidably supporting a respective UPS module 17. A power and control module 18 is mounted on the base portion 12 for coupling to a mains power supply. Each UPS module 17 includes and a number of cooling fans 20 (constituting a heat dissipation unit) for dissipating heat. In an actual embodiment reduced to practice, each UPS module was rated at 25 KVA and five air cooling fans were provided: three toward the front of the UPS module and two toward the rear. Power and control signals are trunked to the UPS modules 17 at the sides of the rectangular frame 11 so as to provide unobstructed access to the cooling fans 20. This represents a significant improvement over hitherto-proposed modular UPS systems which employ rear trunking.

Fig. 4 shows the manner in which rear trunking is avoided. Thus, power busbars 21 are electrically and mechanically connected to power feed lines 22 in the power and control module 18 and extend vertically on respective outer surfaces 23 of the first and second side portions 14 and 15 for providing power to the UPS modules 17. It will be appreciated that while, in such an arrangement, the power busbars 21 are divided between opposing side portions, depending on the dimensions of the side portions and of the power busbars 21, which are determined by the power rating of the UPS modules 17, it may be possible to route the power busbars 21 on a single side portion. In either case, routing the power connections via one or both side portions avoids the need for rear ducting, which would obstruct the air cooling fans 20. Figs. 5 and 6 are perspective views showing details of the power and control module 18. The power and control module 18 comprises three 3-phase contactors 24, 25 and 26 which operate as a static switch for changing the output connection between the UPS and the main line. In this regard, it should be noted that UPS systems are used in one of two ways: either to provide a constant clean and regulated AC voltage with backup battery supply for a limited time in the event of an interruption in the main AC line; or to provide the main AC line supply in the event of a failure in the UPS. In either case, the switchover between UPS and the main AC line is achieved by means of the static switch. The functionality of these contactors is known per se and is not itself a feature of the invention.

However, what is very much a feature of the invention is the manner in which the busbars 21 are connected to the contactors. First, busbars are used owing to the high power rating (250 KVA) of the UPS system 10 and, as noted above, obviates the need to use high-current cables which would prove unwieldy. Secondly, in order to make the power and control module 18 more compact, busbars are used also inside the power and control module 18 since, unlike high-current cables, busbars can be bent to any desired shape. This enables the connections to the contactors to be bent for allowing precise positioning relative to the contactors in order to allow connection thereto and also with respect to the output connections and to the busbars 21 The power busbars 21 are connected to contacts in a first connector 27 at a rear surface of the support units 16 and engage complementary second contacts in a second connector 28 (shown in Fig. 7) at a side of the UPS modules when the UPS module is fully inserted into the support unit 16 and become disconnected therefrom when the UPS module is removed. This allows "hot swap" insertion and removal of one or more UPS modules without requiring interruption of power and more importantly without requiring separate, manual connection of the power to the UPS module 17 after insertion into the rack.

With reference to Figs. 7, 8 and 9 the manner in which a UPS module 17 is supported so as to allow coupling and decoupling of the first and second connectors 27 and 28, will now be explained. The first and second support units 16 mounted on respective inner surfaces of the first and second side portions 14 and 15 serve as opposing first connector assemblies each for slidably supporting a complementary second connector assembly 30 fixed to a respective side of the UPS module 17. As best seen in Fig. 3, the support units 16 include a side wall supporting the first connector 27 (constituting a plurality of contacts) for engaging the second connector 28 (constituting complementary contacts) at a corresponding side surface of the UPS module. A slot 35 within the side surface of the UPS module serves as an integral guide assembly for slidably supporting a pair of lugs 36 protruding from a corresponding side of the UPS module. The guide assembly includes an integral releasable locking mechanism 37 that closes when the UPS module is fully inserted so as to prevent unintended disconnection thereof. The locking mechanism 37 includes a spring-loaded cam 38 that springs into place between the two lugs 36, thereby retaining the UPS module 17 within the support units 16 on either side. To release the UPS module 17, the cam 38 of each support unit 16 is moved out of place by means of a respective lever 39 against the spring bias, whereupon the UPS module 17 may be extracted from the support units 16.

As shown in Fig. 7, the UPS module 17 may include monitoring contacts 40 electrically connected to control terminals in the UPS module and accessible from a front of the modular UPS for connecting a display device 41 thereto.

For the sake of completeness, it is to be noted that control connections are also routed from the power and control module 18 to each of the UPS modules 17. To this end, there is provided in each UPS module 17 a multicore socket 43 for accommodating a complementary plug (not shown) in a similar manner to the connection of peripherals to a computer motherboard.

It will be appreciated that modifications may be made without departing from the scope of the invention as claimed. For example, while typically the heat dissipation unit is constituted by air-cooling fans within each UPS module, an essential feature of the invention is the fact that by routing the power busbars at the sides of the modular UPS system, they do not obstruct the heat dissipation unit. To this end, the benefit of the invention will be realized regardless of the exact nature and disposition of the heat dissipation unit. Other modifications will likewise be apparent to those versed in the art.

Claims

CLAIMS:

1. A modular UPS (10) comprising: a rectangular frame (11) having a base portion (12), a top portion (13) and first and second side portions (14, 15) on opposite sides of the base portion; a respective pair of support units (16) for each UPS module (17) fixedly mounted to respective inner surfaces (23) of the first and second side portions for slidably supporting the respective UPS module; a power and control module (18) mounted on the base portion for coupling to a mains power supply, at least one heat dissipation unit (20) mounted in association with the frame, and a plurality of power busbars (21) extending vertically on an outer surface of at least one of said side portions and electrically connected to power feed lines in the power and control module for providing power to the UPS modules without obstructing the heat dissipation units.

2. The modular UPS according to claim 1, wherein the power busbars are located on both the first side portion and the second side portion.

3. The modular UPS according to claim 1 or 2, wherein the power busbars are connected to first terminals (27) at a rear surface of the support units for engaging complementary second terminals (28) at a side of the UPS modules.

4. The modular UPS according to claim 3, wherein the first terminals become electrically connected to the second terminals of a UPS module when the UPS module is fully inserted into the support unit and become disconnected therefrom when the UPS module is removed thus allowing insertion and removal of one or more UPS modules without requiring interruption of power.

5. The modular UPS according to claim 4, wherein each of the support units (16) includes a first connector (27) mounted on an inner surface of the support unit for engaging a complementary second connector (28) fixed to a respective side of the UPS module.

6. The modular UPS according to claim 5, wherein each support unit (16) includes: a side wall supporting the first connector (27) at a rear surface thereof, and a guide assembly (35) integral with said side wall for slidably supporting the UPS module.

7. The modular UPS according to claim 6, wherein the guide assembly is a slot (35) for accommodating therein one or more lugs (36) protruding from a corresponding side of the UPS module.

8. The modular UPS according to claim 6 or 7, wherein the guide assembly includes an integral releasable locking mechanism (37) that closes when the UPS module is fully inserted so as to prevent unintended disconnection thereof.

9. The modular UPS according to claim 8, wherein the locking mechanism (37) includes a spring-loaded cam (38) that springs into place between a pair of lugs (36) fitted to a side of the UPS module (17).

10. The modular UPS according to any one of claims 1 to 9, wherein at least some of the UPS modules include monitoring contacts (40) electrically connected to control terminals in the UPS module and accessible from a front of the modular UPS for connecting a display device thereto in order to allow external monitoring and control of the modular UPS.

11. The modular UPS according to any one of claims 1 to 10, wherein the heat dissipation unit includes a plurality of fans (20) mounted within each UPS module (17).

12. A UPS module (17) for use with the modular UPS (10) according to any one of claims 1 to 11, the UPS module (17) including on opposite sides thereof respective connector assemblies (30) slidably supported within one of the support units (16) in the UPS module (17) and having contacts (28) for engaging complementary contacts (27) in the support unit (16).

13. The UPS module (17) according to claim 12, further including an integral releasable locking mechanism (37) that is adapted to close when the UPS module is fully inserted into the support unit (16).

14. The UPS module (17) according to claim 13, wherein the locking mechanism (37) includes a pair of lugs (36) for retaining a spring-loaded cam (38) within the support unit (16).

15. The UPS module (17) according to claim 14, wherein the lugs (36) are configured for engaging a slot (35) in a side wall of the respective support unit (16).

16. The UPS module (17) according to any one of claims 12 or 15, including a multicore socket (43) for connecting thereto control lines via a complementary plug.