Abstract:
A system and method of isolating an uninterruptible power supply system is disclosed that comprises bypassing an inverter section of the power supply to couple primary power to a load bus; and, thereafter, isolating the power supply by simultaneously uncoupling the power supply from the load bus and coupling the primary power to the load bus.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation application of and claims benefit of and priority to U.S. patent application Ser. No. 12/984,924 filed on Jan. 5, 2011, which is a continuation application of and claims benefit of and priority to U.S. patent application Ser. No. 11/955,368 filed on Dec. 12, 2007, which is a non-provisional application of and claims benefit of and priority to U.S. Provisional Patent Application Ser. No. 60/942,404 filed on Jun. 6, 2007. The entire contents of all of which are incorporated herein by specific reference. U.S. patent application Ser. No. 11/955,368 issued as U.S. Pat. No. 7,888,816 on Feb. 15, 2011. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       REFERENCE TO APPENDIX 
       [0003]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    The inventions disclosed and taught herein relate generally to uninterruptible power supplies; and, more specifically, relate to paralleled, multi-moduled uninterruptible power supplies. 
         [0006]    2. Description of the Related Art 
         [0007]    Uninterruptible power supplies (UPSs) are employed in an ever-increasing variety of situations where a constant source of power is desired. A typical UPS includes a rectifier section that converts alternating current energy (“AC”) into direct current energy (“DC”). The rectifier section is configured to be coupled to an AC power source, such as a public utility. An inverter section is coupled to the rectifier section and converts DC energy into AC energy, and thereby provides AC energy at an output of the UPS. The UPS may further include, or be coupled to, a backup source of power, such as a battery bank that can feed either AC or DC energy to the UPS when the primary power source is off-line or when the rectifier/inverter sections are disabled. 
         [0008]    UPSs also typically include a bypass circuit to bypass the rectifier/inverter sections and couple the primary AC power source directly to the output bus of the UPS. The bypass circuit, which may be a static switch, can be used, for example, to provide an economy mode of operation and/or to provide power to the load when either or both of the rectifier or inverter sections are damaged or inoperative. 
         [0009]    It is known that UPS bypass circuits may create problems in applications using multiple 
         [0010]    UPSs in parallel to feed a common load, such as a load bus. For example, if the UPS bypass circuit is closed, energy may be backfed from the common load bus through the closed bypass circuit onto the primary power source or into the UPS&#39; power module. 
         [0011]    U.S. Patent Application Publication No. 2005/0288826 purports to disclose a method and apparatus for UPS bypass monitoring and control in which the “status of a bypass source of parallel-connected UPSs is determined from a load share when a loading of the parallel-connected UPSs meets a predetermined criterion. Status of a bypass source of the parallel-connected UPSs is determined from a bypass source voltage when the loading of the parallel-connected UPS s fails to meet the predetermined criterion. The loading may include an aggregate loading, and failure of a bypass source of a UPS may be identified responsive to detecting that a load share of the UPS is less than a predetermined proportion of the aggregate loading. Alternatively, failure of the bypass source may be identified by detecting that a bypass voltage fails to meet a predetermined criterion. Bypass circuits of the UPSs may be controlled responsive to a load share and/or a bypass source voltage.” 
         [0012]    U.S. Patent Application Publication No. 2006/0221523 purports to disclose “a method for controlling an uninterruptible power supply (UPS) for servicing a load. The UPS has a bypass feed path operable in parallel with an inverter feed path, the bypass feed path being engagable with the load via a first switch, and the inverter feed path and being engagable with the load via a second switch. The method includes: generating a paralleling detection signal indicative of the bypass feed path operating to service the load in parallel with the inverter feed path; and, in response to the presence of the paralleling detection signal, modifying a control signal to an inverter such as to drive toward equalization the bypass current and the inverter current. As a result, and in response to the two paths operating to service the load in parallel, the method tends to cancel circulation current generated between the bypass feed path and the inverter feed path. 
         [0013]    U.S. Patent Application Publication No. 2003/0184160 purports to disclose a parallel operation method for an uninterruptible power supply apparatus, “the method being also capable of conducting a parallel non-redundancy operation of uninterruptible power supply apparatuses and having a bypass circuit incorporated therein without using an additional common circuit. In the parallel operation method for uninterruptible power supply apparatus of operating in parallel a plurality of uninterruptible power supply apparatuses, each having two operational modes including a bypass feeding mode and an inverter feeding mode, an off instruction for the AC switch is produced in the respective uninterruptible power supply apparatuses which are operated is in parallel. The off instruction is produced based on a detection result showing coincidence of a pattern of (pattern coincidence detecting circuits 1002, 2002) the bypass feeding signal which is active during the bypass feeding state and a pattern of a ready signal which becomes active when the inverter feeding is ready for conducting.” 
         [0014]    The inventions disclosed and taught herein are directed to an improved method and apparatus for bypassing the rectifier/inverter sections of a UPS and/or the entire UPS system for purposes of performing maintenance on the UPS or discrete components of the UPS. 
       BRIEF SUMMARY OF THE INVENTION 
       [0015]    In one aspect of the invention, a method of isolating an uninterruptible power supply system is provided that comprises bypassing an inverter section of the power supply to couple primary power to a load bus; and, thereafter, isolating the power supply by simultaneously uncoupling the power supply from the load bus and coupling the primary power to the load bus. 
         [0016]    A further aspect of the invention comprises, an uninterruptible power supply system having an uninterruptible power supply comprising a power module coupled to a first power source and an internal bypass circuit coupled to a second power source, both of the power module and the internal bypass selectively couplable to a load bus; a system bypass circuit coupled to either the first or second power source and selectively couplable to the load bus; and means for sequencing the system bypass circuit so that the system bypass circuit is coupled to the load only after the internal bypass is coupled to the load bus. 
         [0017]    Other and further aspects of the invention, including various embodiments, will become apparent upon reading the following detailed disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0018]      FIG. 1  illustrates certain functional and structural aspects of an UPS suitable for use with the present invention. 
           [0019]      FIG. 2  illustrates paralleled UPS s utilizing a maintenance bypass according the present invention. 
           [0020]      FIG. 3  illustrates the systems of  FIG. 2  in which the UPS s have been set to internal bypass. 
           [0021]      FIG. 4  illustrates the system of  FIG. 2  in which the system has been set to maintenance bypass. 
           [0022]      FIGS. 5   a  and  5   b  illustrate a UPS for use with the present invention having an automatic internal bypass feature. 
           [0023]      FIG. 6  illustrates a UPS system having a maintenance bypass with an automatic internal bypass feature. 
       
    
    
     DETAILED DESCRIPTION  
       [0024]    The Figures described above and the written description of specific structures and functions below are not presented to limit the scope of what I have invented or the scope of the appended claims. Rather, the Figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation-specific decisions to achieve the developer&#39;s ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation, location and from time to time. While a developer&#39;s efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of skill in this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. 
         [0025]    Particular embodiments of the invention may be described below with reference to block diagrams and/or operational illustrations of methods. It will be understood that each block of the block diagrams and/or operational illustrations, and combinations of blocks in the block diagrams and/or operational illustrations, can be implemented by analog and/or digital hardware, and/or computer program instructions. Such computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, ASIC, and/or other programmable data processing system. The executed instructions may create structures and functions for implementing the actions specified in the block diagrams and/or operational illustrations. In some alternate implementations, the functions/actions/structures noted in the figures may occur out of the order noted in the block diagrams and/or operational illustrations. For example, two operations shown as occurring in succession, in fact, may be executed substantially concurrently or the operations may be executed in the reverse order, depending upon the functionality/acts/structure involved. 
         [0026]    Computer programs for use with or by the embodiments disclosed herein may be written in an object-oriented programming language, conventional procedural programming language, or lower-level code, such as assembly language and/or microcode. The program may be executed entirely on a single processor and/or across multiple processors, as a stand-alone software package or as part of another software package. 
         [0027]    Lastly, the use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like are used in the written description for clarity in specific reference to the Figures and are not intended to limit the scope of the invention or the appended claims. 
         [0028]    The inventions disclosed and taught herein comprise systems and methods of controlling one or more UPSs by providing a system bypass circuit in addition to any internal bypass associated with each UPS. Closing the system bypass circuit allows the one or more UPSs to be serviced or otherwise taken off line. The systems and methods may comprise placing each UPS into internal bypass prior to placing the UPS system into system bypass. Further, the systems and methods may comprise automatic bypassing and/or restricted bypassing as desired, such as by forcing one or more of the UPSs to go into internal bypass when one or more covers are removed. Additionally or alternately, engaging the system bypass feature may require that one or more of the individual UPS s is placed in internal bypass first. While there are an infinite number of embodiments that utilize one ore more of these inventions, a few specific embodiments are discussed below. 
         [0029]      FIG. 1  illustrates a conventional UPS  10  comprising a power module having a rectifier section  20  and an inverter section  30 . It will be understood that a primary power source (not shown), such as line utility, may supply the UPS at primary input  12 . The Primary AC power is rectified to DC power, which is communicated, such as by a DC bus  22 , to the inverter section  30 , where the DC power is inverted to a form of AC power. Not shown in  FIG. 1  is a back up power source, such as one or more batteries, that can feed the inverter section  30  when the primary power source is offline. Also illustrated in  FIG. 1  is internal bypass  14 , which, as the name implies, bypasses the power module  20 ,  30  of the UPS. The internal bypass  14  is structured to communicate AC power, such as from the primary power source (or a secondary power source), to power output  16  of the UPS. Also illustrated in  FIG. 1  is switch  40  that allows the power output to source from power module  20 ,  30  (as shown in  FIG. 1 ) or from the internal bypass  14 . It will be understood the switch  40  may comprise a mechanical switch, such as a breaker, an electronic switch such as an SCR, or any number of other devices adapted to transfer power as described herein. 
         [0030]    Turning now to  FIG. 2 , a first embodiment of an uninterruptible power supply system  100  utilizing aspects of the present invention is illustrated. A first UPS  10   a  is shown and another UPS  10   n  is shown to represent a plurality of paralleled UPSs  10   a  through  10   n.  For purposes of this disclosure, UPSs  10   a  through  10   n  are illustrated to be identical, but it will be appreciated that non-identical UPSs can be paralleled with the present invention as well. This embodiment of the UPS system  100  shows power input  12   a  through  12   n  drawing power from a primary power source  50  and the bypass circuits  14   a  through  14   n  drawing power from a bypass power source  52 . In certain embodiments and/or applications, the primary power source  50  and bypass power source  52  may comprise the same source, such as a line utility. Illustrated in  FIG. 2  is system or maintenance bypass  60  that connects a power source, such as primary power  50  or bypass power  52  to the load bus  70 . The system bypass  60  comprises a switch  62 , shown in the opened condition. The UPS system  100  also comprises load bus switches  64   a  through  64   n,  which are shown in the closed condition. Although the bypass switch  62 , and the load bus switches  64   a  through  64   n  are illustrated as separate switches, it will be appreciated that a single multi-pole switch, whether mechanical or electronic or a combination thereof, may be used as well. The system of  FIG. 2  is shown in the normal operating mode of the UPS system in which power from the primary source  50  is passed through the power modules  20   a - n,    30   a - n  through the load bus switches  64   a  though  64   n  and on to the load bus  70 . Bypass switch  62  as well as the internal bypass circuits  14   a  through  14   n  are in the opened condition. 
         [0031]      FIG. 3  illustrates the UPS system  100  in internal bypass mode. As can be seen, UPS switches  40   a  through  40   n  have been activated such that the power modules of the paralleled UPS have been bypassed. Power from the bypass power source  52  (which may be the same as primary power source  50 ) is passed through to the load bus  70  via load bus switches  64   a  through  64   n.  Activation of the UPS switches  40   a  through  40   n  may be accomplished by any known means, including wired or wireless activation or mechanical activation, remotely or directly. 
         [0032]      FIG. 4  illustrates the UPS system  100  in system bypass mode. As can be seen, UPS switches  40   a  through  40   n  have been activated such that the power modules of the paralleled UPS have been bypassed. Thereafter, system switch  62  and load bus switches  64   a  through  64   n  are closed and opened, respectively, simultaneously or substantially simultaneously so that power on the load bus  70  is substantially uninterrupted. In this condition, power from the bypass power source  52  (which may be the same as primary power source  50 ) is passed through to the load bus  70  via bypass switch  62  thereby bypassing all of the paralleled UPSs, including their power modules  20   a - n,    30   a - n.  Activation of the system switch  62  and the load bus switches  64   a  through  64   n  may be accomplished by any known means, including wired or wireless activation or mechanical activation, remotely or directly. 
         [0033]    It will be appreciated that once the UPS system illustrated in  FIG. 4  is placed in system bypass mode, one or more bypassed UPSs may be removed or otherwise serviced. It will also be appreciated that by requiring each targeted UPS, such as UPSs  10   a  through  10   n,  to be placed into internal bypass prior to engaging the system bypass  12 , potentially damaging or harmful back feed is thereby prevented or minimized. 
         [0034]      FIGS. 5   a  and  5   b  illustrate aspects of a preferred UPS for use with the present inventions. UPS  80  comprises a power module  82  (comprising a rectifier section and an inverter section), an internal bypass  84  and a UPS switch  86 , as discussed previously. In addition, UPS  80  comprises one or more contacts or switches  88 , such as mechanical micro-switches, adjacent selected covers or panels  90 . The switch  88  communicates with UPS switch  86  so that a change in state of switch  88  causes a change in state of UPS switch  86 . For example, a switch  88  may be placed adjacent a primary access panel  92 , such that removal of the panel by, for example, a service technician, causes a change in state of switch  88 , such as from opened to closed or vice versa. This change in state is communicated, preferably electronically, to UPS switch  86 , which causes switch  86  to change state correspondingly. In a preferred embodiment of UPS  80 , removing the panel  92  causes the UPS switch to place the UPS  80  into bypass mode, as illustrated in  FIG. 5   b.    
         [0035]      FIG. 6  illustrates a preferred UPS system  200  comprising a plurality of paralleled UPSs  80  (only one shown for clarity) such as described above with respect to  FIG. 5 .  FIG. 6  also illustrates system bypass  100  comprising a switch  102 , such as described previously. The system bypass switch  102  may preferably comprise a mechanical breaker switch having multiple poles corresponding to the number of paralleled UPSs. In this configuration, the system switch  102  also comprises load bus switches  102   a  through  102   n  (not shown). It will be appreciated that the system switch  102  may be adapted such that when switch  102  is open, the load bus switches  102   a - n  are closed, and vice versa. Also shown in  FIG. 6  is system switch interlock  104 , which may comprise a bar, panel, or other physical structure that impedes or prevents actuation of system switch  102 . The system bypass is also disclosed to comprise an interlock switch  106 , such as mechanical micro-switch. When the interlock  104  is moved or removed, the switch  106  changes state and causes the UPS switches  86   a  through  86   n  (not shown) to enter the internal bypass condition. Thereafter, actuation of the system bypass switch  102  cause the UPS to go into system bypass without producing damaging backfeed on the UPS power modules. 
         [0036]    Other and further embodiments utilizing one or more aspects of the inventions described above can be devised without departing from the spirit of my invention. For example, a suitable programmed controller can stage the internal bypass functions followed by the system bypass function. Further, the various methods and embodiments of the present invention can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice-versa. 
         [0037]    The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions. 
         [0038]    The inventions have been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by me, but rather, in conformity with the patent laws, I intend to fully protect all such modifications and improvements that come within the scope or range of equivalent of the following claims.