Abstract:
A method may include generating an efficiency curve for each of a plurality of power sources and operating the plurality of power sources based at least on the generated efficiency curve. Generating the efficiency curve for each power source may include coupling a test load to the power source for a period of time, measuring an output power after the period of time, determining a productivity of the power source, determining an efficiency of each power source based at least on the measured output power and the determined productivity, repeating the efficiency determination of the power source for a plurality of different test loads, and generating an efficiency curve from at least the determined efficiencies.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to system power management, and more particularly, to efficient power source usage in a redundant power source configuration. 
       BACKGROUND 
       [0002]    As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as, but not limited to, financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. 
         [0003]    With the advent of power hungry information handling systems, power management has become more important. In the past, conserving power has typically been secondary to speed and processor availability. However, due to the increased processing demands required by today&#39;s software and Internet websites, more information handling systems utilize multi-processor systems that require more power to operate than single processor computer systems. In addition, as processor designs continue to scale up in speed and density, corresponding power consumption can increase dramatically, requiring more efficient power management. 
         [0004]    While the processing demands and device consumptions are often driving factors in managing and conserving power, other factors such as network failures, blackouts, and other device, system, or mechanical failures may also be motivators in reducing and efficiently managing power consumption. Current solutions often employ a power source management, sequencing, and conservation technique to handle the inrush and steady state load demands, as well as redundancy and efficiency requirements of power sources. Demand triggered power sources have attempted to reduce power consumption by starting up additional power sources based upon the load on the system. However, the current techniques generally do not account for inrush source, choose the most efficient power source to start from a pool of available power sources, or provide for enterprise wide power conservation. 
         [0005]    Further, in multiple redundant power sources, and where the power sources are load sharing, the more power sources brought online generally causes a reduction in efficiency. For example, a power source with a rating of 600 Watts may operate at about 600 Watts (minus any loss due to a load). Alternatively, in a redundant configuration, two power sources, each with a 600 Watt rating, may both be coupled to a single load and may each have an output of about 300 Watts, thus not effectively using the power sources. 
       SUMMARY 
       [0006]    In accordance with an embodiment of the present disclosure, a method may include generating an efficiency curve for each of a plurality of power sources and operating the plurality of power sources based at least on the generated efficiency curve. Generating the efficiency curve for each power source may include coupling a test load to the power source for a period of time, measuring an output power after the period of time, determining a productivity of the power source, determining an efficiency of each power source based at least on the measured output power and the determined productivity, repeating the efficiency determination of the power source for a plurality of different test loads, and generating an efficiency curve from at least the determined efficiencies. 
         [0007]    In accordance with another embodiment of the present disclosure, a method for operating a plurality of power sources configured in a redundant configuration based at least on a generated efficiency curve is provided. An efficiency of at least one power source of the plurality of power source may be determined and a corresponding data point may be generated. The method may also include determining other efficiency and generating other data point generation for a plurality of other test loads. An efficiency curve from the generated data points may be generated and the plurality of power sources may be operated based at least on the generated efficiency curve. 
         [0008]    In accordance with a further embodiment of the present disclosure, an information handling system may include a processor, a memory communicatively coupled to the processor, display device coupled to the processor, a plurality of power sources coupled to the processor, and a controller may be provided. The controller may be communicatively coupled to the plurality of power sources. In addition, the controller may be operable to couple a test load to each of the power sources for a period of time, measure an output power after the period of time, determine a productivity of the power source, and determine an efficiency of power source based at least on the measured output power and the determined productivity. The controller may further be operable to repeat the efficiency determination of the power source for a plurality of different test loads and generate an efficiency curve from the efficiency determinations. The controller may operate the plurality of power sources based at least on the generated efficiency curve. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    A more complete understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein: 
           [0010]      FIG. 1  illustrates a block diagram of an example information handling system, in accordance with embodiments of the present disclosure; 
           [0011]      FIG. 2  illustrates a flow chart of an example method for determining the efficiency of a power source, in accordance with embodiments of the present disclosure; 
           [0012]      FIG. 3  illustrates a flow chart of an example method for determining the efficiency of one or more power sources, in accordance with embodiments of the present disclosure; and 
           [0013]      FIGS. 4 and 5  each illustrate a set of example efficiency curves, in accordance with embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Preferred embodiments and their advantages are best understood by reference to  FIGS. 1-5 , wherein like numbers are used to indicate like and corresponding parts. 
         [0015]    For purposes of this disclosure, an information handling system may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and/or a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components. 
         [0016]      FIG. 1  illustrates a block diagram of an example information handling system  100 , in accordance with an embodiment of the present disclosure. As shown in  FIG. 1 , information handling system  100  may include a processor  102 , memory  104 , a network port  106 , a display  108 , and a plurality of redundant power sources  110 . Processor  102  may comprise any system, device, or apparatus operable to interpret and/or execute program instructions and/or process data, and may include, without limitation, a microprocessor, microcontroller, digital signal processor (DSP), application specific integrated circuit (ASIC), or any other digital or analog circuitry configured to interpret and/or execute program instructions and/or process data. In some embodiments, processor  102  may interpret and/or execute program instructions and/or process data stored in memory  104  and/or another component of information handling system  100  and may output results, graphical user interfaces (GUIs), websites, and the like via display  108  or over network port  106 . 
         [0017]    Memory  104  may be coupled to processor  102  and may comprise any system, device, or apparatus operable to retain program instructions or data for a period of time. Memory  104  may be random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), a PCMCIA card, flash memory, or any suitable selection and/or array of volatile or non-volatile memory that retains data after power to information handling system  100  is turned off. 
         [0018]    Display  108  may comprise any display device suitable for creating graphic images and/or alphanumeric characters recognizable to a user, and may include, for example, a liquid crystal display (LCD) or a cathode ray tube (CRT). 
         [0019]    Network port  106  may be any suitable system, apparatus, or device operable to serve as an interface between information handling system  100  and a network. Network port  106  may enable information handling system  100  to communicate over a network using any suitable transmission protocol and/or standard, including without limitation all transmission protocols and/or standards known in the art. 
         [0020]    Power sources  110  may include any device, system, or apparatus operable to supply power or electrical energy to one or more components of information handling system  100 . For example, power sources  110  may include any system, device, and/or apparatus operable to supply direct current (DC) electrical power to one or more components of information handling system  100 . In some embodiments, a DC power source may comprise a battery. In the same or alternative embodiments, a DC power source may comprise an AC/DC adapter that may convert 120- or 240-volt (or any other suitable voltage) alternating current supplied by a utility company to a regulated lower voltage DC power source. In addition, an AC/DC adapter may also charge a battery while supplying power to information handling system  100 . 
         [0021]    In addition or alternatively, power sources  110  may include any system, device, and/or apparatus operable to supply AC electrical power directly to one or more components of an information handling system. In some embodiments, the AC power source may subsequently be converted into a DC power source (e.g., using an AC/DC converter). 
         [0022]    In some embodiments, power sources  110  may include one or more uninterruptible power sources and/or switch mode power sources either internal and/or coupled externally to information handling system  100 . In some embodiments, power sources  110  may be assembled in a redundant configuration (e.g., one or more power sources may be configured to share a load current such that failure of a single power source may not substantially affect the load current) within, for example, a multi-source chassis that may be coupled to information handling system  100 . Alternatively, power sources  110  may include an array of power sources, e.g., an array of programmable DC power sources. 
         [0023]    A controller  112  may be coupled to the plurality of power sources  110 . Controller  112  may include any hardware, firmware, and/or software for determining the productivity of individual power sources  110  as well as the productivity of various combinations of power sources  110  (e.g., in a load sharing configuration). For example, controller  112  may read each power source&#39;s field replaceable unit (FRU) or nameplate to determine the power rating of each power source  110 . Controller  112  may also test power sources  110  to determine the input and/or output capabilities of one, some, or all of power sources  110  for supplying power to various loads. This may allow controller  112  to apply power sources  110  to components of information handling system  100  efficiently (e.g., to efficiently provide power to the various components or loads associated with information handling system  100 ). This process is described in more detail below. 
         [0024]      FIG. 2  illustrates a method for efficiently utilizing a redundant power source configuration, in accordance with an embodiment of the present disclosure. At step  201 , controller  112  may select and/or characterize at least one power source  110 . Controller  112  may be in direct or indirect communication with each of the power sources  110  and may be able to power on or off each power source  110  during the selection step. In some embodiments, controller  112  may select each power source  110  in a serial manner for testing. Controller  112  may select one or more than one power source  110  for testing. 
         [0025]    At step  202 , controller  112  may determine the productivity of the selected power source(s)  110 . For example, controller  112  may read the replaceable unit (FRU) or nameplate of the power source(s)  110  to determine the rated output power of selected power source(s)  110 . 
         [0026]    At step  203 , controller  112  may couple a load to the selected power source  110  and power on the selected power source(s)  110 . One, some, or all the components of system  100  may be used as a test load. Alternatively, controller  112  may couple other test loads known in the art to the selected power source(s)  110 . In one embodiment, after coupling the test load to the selected power source(s)  110 , controller  112  may turn on the power source(s)  110 , wait for the power source(s)  110  to stabilize, and record sample input and/or output power taken from the power source(s)  110 . To ensure the test load is stabilized while coupled to the power source(s), some or all components of information handling system  100  may be placed in a reset state or in a memory test state such that the power load is stable. The stable load may allow controller  112  to sample the power source(s) over a period of time, which may provide a more accurate output power readout as compared to a test load that varies over the period of time. 
         [0027]    At step  204 , a data point representing the power efficiency of the selected power source  110  coupled to the test load may be determined and plotted on a graph. The power efficiency data point may be based on at least the productivity of the selected power source (from step  202 ) and the recorded output power (step  203 ) for the test load. For example, the power efficiency may be a ratio of the output power recorded for a given load to the rated power output for the selected power source  110 . 
         [0028]    At step  205 , a determination is made whether to test the selected power source(s)  110  using one or more other test loads. If so, controller  112  may couple one or more other test loads to the selected power source(s)  110  and repeat steps  203  and  204  to determine one or more additional power efficiency data points for the selected power source  110 . Alternatively, as discussed below with reference to the method of  FIG. 3 , controller  112  may combine the selected power source(s)  110  with one or more additional power sources  110  and test the combined power sources  110  using one or more test loads (e.g., using a shared load configuration). 
         [0029]    Steps  203  and  204  may be repeated any number of times, using any selected test loads and additional power sources  110  in order to generate additional data points. The data points may be plotted to generate an efficiency curve for the selected power source(s)  110 , e.g., as discussed below with reference to  FIG. 4  or  5 . 
         [0030]    At step  207 , once an efficiency curve (or efficiency curves) have been generated for the selected power source(s)  110 , controller  112  may utilize the efficiency curve(s) (along with a redundancy policy associated with system  100 ) to manage the power efficiency of system  100 . It is noted that for each system, the efficiency with respect to the percentage of output power may vary. 
         [0031]    For example, controller  112  may review the efficiency curves for each power source  110 , or any combination of the power sources  110 , to determine which power source  110  or power sources  110  may be efficient to power one, some or all of the components of information handling system  100 . 
         [0032]      FIG. 3  illustrates a flowchart for testing multiple power sources  110  at step  203  of the method shown in  FIG. 2 , according to embodiments of the present disclosure. At step  306 , controller  112  may power on one or more additional power sources  110  (i.e., in addition to the original selected power source(s)  110 ) and couple the additional power source(s)  110  with power source(s)  110  selected at step  201  of the method of  FIG. 2 . The multiple powered power sources  110  may then be coupled to a test load. 
         [0033]    At step  310 , controller  112  may determine if the powered power sources  110  (i.e., the power source(s) selected at step  201  and the additional power source(s) powered at step  306 ) are collectively capable or sufficient to power the test load. If the output power of the powered sources are sufficient, at step  312 , controller  112  may record the output power of power sources  110  and plot a data point, e.g., as described above regarding steps  203  and  204  of  FIG. 2 . 
         [0034]    However, as shown in  FIG. 3 , if the output power of the powered power sources  110  is not sufficient to power the test load, the method may return to step  306  and controller  112  may turn on additional power sources  110 . In addition or alternatively, controller  112  may power off at least one of the powered sources  110  to test the efficiency of the selected power sources  110  from step  201  and any remaining powered sources from step  306 . For example, in embodiments where more than one power source  110  is powered on, controller  112  may power on a new power source  110  and turn off a prior powered power source  110 . 
         [0035]    The processes described above regarding  FIGS. 2 and 3  may be repeated any number of times in order to generate multiple data points, and thus efficiency curves, for individual power sources  110  and/or various combination of multiple power sources  110 . One of ordinary skill in the art may recognize the more data points plotted for a particular efficiency curve, the more accurate or useful the curve. 
         [0036]      FIG. 4  illustrates example efficiency curves for a plurality of power sources  110 , in accordance to embodiments of the present disclosure. In particular,  450  may represent a first power source of power sources  110 , efficiency curve  452  may represent the efficiency of a second power source of power sources  110 , and efficiency curve  454  may represent the efficiency of the combination of the first and second power sources. Data point  220  represents an example data point, which may be generated at step  204  in  FIG. 2 , for example. 
         [0037]    To illustrate with an example, if the load from information handling system  100  requires about 40% of the output power supplied by power sources  110 , controller  112  may look to efficiency curve  450 ,  452 , and  454  to determine which power sources are needed. At 40%, the first power source  110  with efficiency curve  450  may provide the most efficiency as compared to second power source  110  and the combination of the first and second power sources  110 . By utilizing the efficiency curve, only the necessary power source(s)  110  needed for a load may be powered and applied to the various components of information handling system  100 . 
         [0038]      FIG. 5  illustrates another set of example efficiency curves, in accordance with embodiments of the present disclosure. Efficiency curve  550  may represent a first 900 Watt power source (Power Source A), efficiency curve  552  may represent the efficiency of a second 900 Watt power source (Power Source B), and efficiency curve  554  may represent a third 900 Watt power source (Power Source C). 
         [0039]    To illustrate with an example, if one or more components of information handling system  100  require less than about 450 Watts, Power Source A may preferably be used for powering such component(s). Referring to efficiency curve  550  of  FIG. 5 , at the wattages below 450 (line  556 ), Power Source A is more efficient than Power Source B or Power Source C. 
         [0040]    Likewise, if one or more components of information handling system  100  require between 450 and 750 Watts, Power Source B may preferably be used for powering such component(s). Referring to efficiency curve  552 , between 450 Watts (line  556 ) and 750 Watts (line  558 ), Power Source B is more efficient than Power Source A or Power Source C. 
         [0041]    For any load greater than about 750 watts (line  558 ), the efficiency of Power Sources A, B, and C are about the same, and thus any of the power sources may be used. 
         [0042]    In a redundant configuration where, for example, two power sources may be provided redundantly, a combination of curves  550 ,  552 , and/or  554  may be evaluated by controller  112 . For example, between about 0 to 625 Watts (line  560 ), efficiency curves  550 ,  552 , and  554  indicate that Power Sources A and B are a more efficient combination than Power Sources A and C or Power Sources B and C (particularly due to the relative inefficiency of Power Source C below 625 Watts). 
         [0043]    By utilizing efficiency curves generated as described herein, controller  112  may apply the appropriate power source(s)  110  (either in a non-redundant or redundant configuration) to one, some, or all components of information handling system  100  in order to increase or maximize the power efficiency of system  100 . 
         [0044]    Although the present disclosure has been described in detail, it should be understood that various changes, substitutions, and alterations can be made hereto without departing from the spirit and the scope of the invention as defined by the appended claims.