Abstract:
A scalable liquid cooled power system using a number of modularized, hot-plug, hot-swap, and scalable liquid-cooled power conversion modules mounted on mating mounting assemblies. A modularized, scalable liquid coolant manifolds and liquid cooling management system provides coolant circulation through the power conversion modules. The system optionally includes a highly scalable system control and administration system, and optionally provides the facility for on-board liquid-to-air heat exchanger system, or off-board cooling using an external heat exchanger system.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims one or more inventions which were disclosed in Provisional Application No. 62/073,204, filed Oct. 31, 2014, entitled “Modular Scalable Liquid Cooled Power System”. The benefit under 35 USC §119(e) of the United States provisional application is hereby claimed, and the aforementioned application is hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention pertains to the field of cooling electronic systems. More particularly, the invention pertains to methods of cooling electronics using circulating liquid. 
         [0004]    2. Description of Related Art 
         [0005]    Electronic systems that involve a significant amount of heat generation as part of their functionality, or are deployed in an area that subjects them to environmental contamination, or are deployed in areas that require a low acoustical noise signature, oftentimes require liquid cooling. Liquid cooling also can provide the opportunity to significantly reduce overall system size and cost. 
         [0006]    Liquid cooling can be realized via several different methods. For example, heat that is dissipated into the local system environment via convection can be transferred to a localized air-to-liquid heat exchanger. Alternatively, heat from electronic components can be transferred directly to liquid coolant via conduction. 
         [0007]    When conduction cooling is employed, the general state of the art is to use assemblies that are plumbed in place to the host system&#39;s liquid coolant distribution and management system. Such assemblies are typically difficult to repair after a malfunction as they have to be disconnected from the cooling system. 
         [0008]    Condensation is a risk in liquid cooled applications where the coolant is supplied from a source that provides coolant at temperatures below the dew point. This can cause sensitive electronic parts to fail and leaves the system unserviceable. Adequate condensation mitigation techniques should be in place to prevent condensation happening in the vicinity of electronic components. 
         [0009]    Likewise, the sub-system cabinet these assemblies are contained within is highly customized, providing limited flexibility regarding system expansion or upgrade. With power conversion systems in particular, the ability for a flexible, easy-to-maintain and cost effective architecture is highly desirable. Flexibility areas include setting the amount of power available for a given application, the liquid cooling system, input power management and distribution system, output power management and distribution system, and administrative functions. 
       SUMMARY OF THE INVENTION 
       [0010]    The scalable liquid cooled power system of the invention provides a system architecture using a number of modularized, hot-plug, hot-swap, and scalable liquid-cooled power conversion modules mounted on mating mounting assemblies. A modularized, scalable liquid coolant manifolds and liquid cooling management system provides coolant circulation through the power conversion modules. The system optionally includes a highly scalable system control and administration system, and optionally provides the facility for on-board liquid-to-air heat exchanger system, or off-board cooling using an external heat exchanger system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0011]      FIG. 1  shows how the modular blocks are configured. 
           [0012]      FIG. 2  shows a detail of power connections from box I in  FIG. 1 . 
           [0013]      FIGS. 3 a -3 d    show top, front, back and side views of a blind-mate liquid cooled power module, respectively. 
           [0014]      FIG. 4  shows a rear view of an eight unit cluster of modules. 
           [0015]      FIG. 5  shows a DC power connection and distribution electrical schematic for a system of modules. 
           [0016]      FIG. 6  shows a block diagram of a coolant manifold system. 
           [0017]      FIG. 7 a    shows an overview of the arrangement of a control system. 
           [0018]      FIG. 7 b    shows the functional data flow of the system of  FIG. 7   a.    
           [0019]      FIG. 8 a    shows a front view of a coolant system. 
           [0020]      FIG. 8 b    shows a side view of a coolant system. 
           [0021]      FIG. 8 c    shows a back view of a coolant system. 
           [0022]      FIG. 9  shows a 500 kW power system. 
           [0023]      FIG. 10  is a transparent view of the system of  FIG. 9 . 
           [0024]      FIG. 11  shows a cabinet mounting assembly with a module as shown in  FIGS. 3 a   - 3   d.    
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    As shown in dashed lines in the block diagram of  FIG. 1 , the Modular Scalable liquid-cooled power system is built around the following major functional blocks:
   I. Input power connection and input power internal distribution system   II. Modular—blind mate, hot plug power conversion modules configured as blocks. In general, the scalable liquid cooled power system is set to support modular power converters in blocks of up to eight (8) modules  13   a  . . .  13   n,  although other cluster sizes are possible.   III. Output power connection and output power internal distribution system   IV. Liquid coolant system   V. Control and administration system   VI. Optional liquid-to-air heat exchanger system   
 
         [0032]      FIG. 1  presents how these blocks are configured for the system. 
         [0033]    Block No. I, the Input Power Connection and Distribution System, comprises an input power connection point  2 , which accepts the input power connection  1  of a size and amperage appropriate to the power being delivered. This power connection is then broken into separate feeds  14   a,    14   b,    14   c  . . .  14   n,  by the Input Power Internal Distribution System  5 . The individual feeds  14   a,    14   b,    14   c  . . .  14   n  each feed one of the individual power modules  13   a,    13   b,    13   c  . . .  13   n.    
         [0034]      FIG. 2  shows a detail of block I. This arrangement provides for practical sizing of AC input conductors  1 , allowing for extreme versatility of the main AC input feeder, where this can be cables or bus bars. Intermediate cables  21  are sized to provide cordage that is manageable from the weight, bend radius and cost aspects. Other controllers may be linked in through connections  22 . 
         [0035]    Block No. II comprises a plurality of Modular—blind mate, hot plug power conversion modules  13   a,    13   b,    13   c  . . .  13   n,  configured as blocks. The power conversion modules  13   a - 13   n  are liquid cooled through coolant from the coolant connection distribution and management system  16  by supply line  8  and coolant return line  9 . Input power is supplied to each module  13   a - 13   n  by individual feeds  14   a - 14   n,  and output power produced by the modules  13   a - 13   n  is supplied to output power internal distribution system  10  in functional block III, discussed below, through individual outputs  15   a,    15   b,    15   c  . . .  15   n.  The modules  13   a - 13   n  are connected to a control bus  7  from system controller  4 , as will be discussed in greater detail below. 
         [0036]      FIGS. 3 a  to 3 d    present top, side, front and back views of a typical module  30 , which can be used interchangeably as any of the modules  13   a - 13   n  shown in  FIG. 1 . As shown in  FIGS. 3 a  and 3 c   , the back panel  38  of the case of each module  30  has blind-mate connectors for power input  34 , power output  31  and control  35 . The module  30  also has connectors for coolant input  32  and coolant output  33  on the back panel  38 , through which coolant can circulate. The front panel  39  of the module  30  can be fitted with handles  36  and fixing screws  37 , as is conventional in rack-mount electronics. 
         [0037]      FIG. 11  shows a cabinet mounting assembly  40  for use with the module  30  detailed in  FIGS. 3 a   - 3   c,  with a module  30  partially inserted into the assembly  40 . The mounting assembly  40  has a shelf portion  49  for supporting the module  30 . Threaded connectors  47  are provided into which the fixing screws  37  on the front panel  39  of the module  30  can be screwed to secure the module  30  in the mounting assembly  40  after the module  30  has been fully inserted into the mounting assembly  40 . 
         [0038]    A back plane  48  of the mounting assembly  40  has blind-mate connectors  41 - 45  which match the blind-mate connectors  31 - 35  on the back panel  38  of the module  30 . Through this arrangement, when the module  30  is fully seated in the mounting assembly  40  by being slid completely to the rear, the connectors  31 - 35  on module  30  make secure connection to connectors  41 - 45  on mounting assembly  40 . 
         [0039]    In this way, coolant from the coolant connection distribution and management system  16  is supplied to module  30  through coolant supply line  8  to liquid coolant input connector  42  on the mounting assembly  40  and then through liquid coolant input connector  32  to module  30 . Returned coolant from module  30  exits through liquid coolant output connector  33  into liquid coolant output connector  43 , and then back to the coolant connection distribution and management system  16  through coolant return line  9 . 
         [0040]    One of the power input lines  14   a - 14   n  would be connected to power input connector  41  on the mounting assembly, which would supply power to module  30  through mating power input connector  31 . Power output from module  30  would be supplied to power output connector  34 , which would mate with power output connector  44  on the mounting assembly  40 , which in turn would be connected to one of the power output lines  15   a - 15   n.    
         [0041]    Finally, control signals from system controller  4  would be supplied on control line  7  to control connector  45  on the mounting assembly  40 , which mates with control connector  35  on the module  30 . 
         [0042]    It will be understood that the specific connectors and connections shown in the figure are for illustrative purposes, and alternative or additional connectors may be provided, and the connectors arranged in different arrangements, within the teachings of the invention. 
         [0043]      FIG. 4  shows a rear view of an 8-unit cluster of mounting assemblies  40   a - 40   h.  Each of the mounting assemblies  40   a - 40   h  has a coolant input connector  42  and coolant output connector  43 . All of the coolant input connectors  42  are fed by coolant supply manifold  8  running along the back of the cluster, and all of the coolant output connectors  43  feed into coolant return manifold  9 . Each of the mounting assemblies  40   a - 40   h  has its power output connectors  44 , with the positive DC+ connected to bus  53  and the negative DC− connected to bus  54 . The power input connectors  41  on each mounting assembly  40   a - 40   h  can be connected in parallel, or individual lines  14   a - 14   h  provided as in  FIG. 1 . Finally, each mounting assembly  40   a - 40   h  has its control input  45  available for connection to the system controller  4 . If desired, the control inputs  45  can be daisy chained together or connected in parallel to a communications bus, as is known to the art. 
         [0044]    Block No. III comprises the output power connection point  11  and output power internal distribution system  11 . Power from the individual power conversion modules  13   a - 13   n  is supplied to the output power internal distribution system  11  through lines  15   a - 15   n.  The combined power of the power conversion modules  13   a - 13   n  is supplied to the output power connection point  11 , which then supplies output power  12  to external components as needed. 
         [0045]      FIG. 5  provides a schematic depiction of block III, in an example embodiment with eight modules. In this example, the output power lines  15   a - 15   h  from the modules each comprise a positive (DC+) and negative (DC−) wire. The DC+ wires from lines  15   a - 15   h  are combined in power collection system  10  into a single line  51 , which supplies DC+ bus  53  in the system DC connection point  11 , and this bus  53  provides positive voltage to the system power output  12 . Similarly, The DC− wires from lines  15   a - 15   h  are combined in power collection system  10  into a single line  52 , which supplies DC− bus  54  in the system DC connection point  11 , and this bus  53  provides negative voltage to the system power output  12 . 
         [0046]    Block No. IV is the Liquid coolant system, in which the Coolant Connection, Distribution and Management System  16  supplies coolant to coolant supply manifold  8 , and accepts the warmed coolant back through coolant return manifold  9 . The Coolant Connection, Distribution and Management system  16  can be monitored and controlled by the system controller  4  through a Cooling System Control Interface  6 . 
         [0047]    As depicted in  FIG. 6 , coolant supply manifold  8  is preferably built up of modular scalable manifolds  65   a  and  65   b  that can be assembled together to form the manifold  8 . Similarly, coolant return manifold  9  is preferably built up of modular scalable manifolds  66   a  and  66   b  that can be assembled together to form the manifold  9 . Also shown in  FIG. 6  are optional flow control solenoid  63 , controlled by line  64  from the cooling system control interface  6 , and optional pressure sensor  61  which sends pressure data by line  62  to the cooling system control interface  6 . The cooling system control interface  6  is controlled by or reports back to the system controller described in Block No. V, below. 
         [0048]    Block No. V, the Control and administration system, consists of an electronic power system control module  4  that communicates over module control line  7  to the power converter modules  13   a - 13   n.  The module control line  7  is preferably a serial digital communication bus operating a communications protocol known to the art, such as the Controller Area Network (CAN) BUS protocol. 
         [0049]      FIG. 7 a    provides detail of the control system of Block V. As depicted in  FIG. 7 , the power system controller  4  acts as a portal for communication with the external host  70  through the external system control interface  3 . The external host  70  can be connected to the system control interface  3  via one or more or a combination of serial digital, parallel digital, or analog signal connections  71 . The connections may be wired or wireless, and might be connected through a local area network (LAN) or wide area network (WAN), or through a global network such as the Internet or private networks. The controller also administers the power conversion modules via a series connected serial digital bus, such as the aforementioned CAN bus. 
         [0050]    The controller  4  also acts to control the liquid coolant system through either a control link  6  to the coolant connection, distribution and management system  16 , through control of flow valves  63  connected to the power module distribution and collection manifolds described in  FIG. 6 . The controller  4  can also collect information regarding coolant system pressure through the same link  6  from the pressure sensor  61  depicted in  FIG. 6 . Optionally, the controller  4  can monitor and/or control an optional heat exchanger through heat exchanger control interface  5 . 
         [0051]      FIG. 7 b    shows a functional data flow diagram for the power system controller  4 . The external system control interface  3  may be connected to an Ethernet Jack  72 , which routes data to and from an Ethernet transceiver  73 . The Ethernet transceiver  73  communicates bidirectionally with a microcontroller  74 , so that commands can be received from, and data sent to, the external system controller  70 . 
         [0052]    To send commands to, and receive data from, the power conversion modules  13   a,    13   b  . . .  13   n,  the microprocessor communicates bidirectionally with a CAN transceiver  75 . The CAN transceiver  75  is connected to a CAN BUS jack  76 , into which the control bus  7  is plugged. All of the power conversion modules  13   a - 13   n  are connected to the control bus  7  through a CAN BUS jack  77 , through which a CAN transceiver  78  sends and receives data from the bus  7 . The CAN transceiver  78  is bidirectionally connected to a microprocessor  79  in the power conversion module  13   a - 13   n,  which controls the module and measures various parameters as known to the art. 
         [0053]    Block No. VI is an Optional liquid-to-air heat exchanger system. This system provides a means of dissipating heat that is generated by the power conversion process from the coolant connection distribution and management system  16 . Depending on system climatic requirements, this heat exchanger can be configured to utilize passive convection/radiation or active refrigeration. 
         [0054]      FIGS. 8 a -8 c    depicts an example of a heat exchanger sized to accommodate a power system that produces 500 kW of DC power and operates in an ambient temperature of up to 50° C. 
         [0055]    The heat exchanger  80  in  FIGS. 8 a -8 c    is coupled to the coolant connection, distribution and management system  16 . The heat exchanger  80  preferably has an on board coolant reservoir  85  and pump  86 . The pump  86  pumps coolant from the reservoir  85  to the to the coolant connection, distribution and management system  16 , which distributes it through the coolant supply manifold  8  as described above. 
         [0056]    Coolant which was heated by the power conversion modules  13   a - 13   n  is returned via coolant return manifold  9  to the coolant connection, distribution and management system  16 , which sends the coolant externally to the heat exchanger  80  to discharge heat in the coolant into the ambient environment. 
         [0057]    The heat exchanger  80  uses two liquid-to-air heat exchangers  81  and  82  operating in series to dissipate the heat. Operation of these heat exchangers  81  and  82  is optimized through the use of forced air cooling, here shown as a fan  83  powered by motor  84 , in which air is drawn through the heat exchangers  81  and  82 , cooling the coolant, and then is exhausted through the top of the external heat exchanger  80 . After passing through the two heat exchangers  81  and  82 , the coolant is returned to the reservoir  85 , from which pump  86  will pump it back to the power system to complete the coolant system circuit. Alternatively, the coolant from the heat exchangers  81  and  82  could go directly to pump  86 , instead of to the reservoir  85 , and the reservoir  85  would be used to maintain the level of the coolant supply as needed. This allows the external heat exchanger  80  to provide for the coolant flow needs of the power system. 
         [0058]    When taken all together, the scalable liquid cooled power system can be configured to serve needs as low as 15 kW (or lower), or as high as 500 kW in a single 19″ standard NEMA cabinet. 
         [0059]      FIG. 9  presents a sample implementation for a 500 kW system.  FIG. 10  shows the elements shown in  FIG. 9  with a transparent view. 
         [0060]    In the example of  FIGS. 9 and 10 , there are two cabinets: a rack  90  for the power conversion modules  91 , which is preferably a 19″ standard NEMA cabinet, and an external heat exchanger  92  as described above in the discussion of  FIG. 8 . 
         [0061]    Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.