Abstract:
A modular power distribution system comprises a chassis; and a backplane including a power input, and a plurality of module connection locations. A plurality of modules are mounted in the chassis, each module mounted to one of the module connection locations. Each module includes: (i) an OR-ing diode; (ii) a circuit protection device; (iii) a microprocessor controlling the circuit protection device; and (iv) a power output connection location. A circuit option switch is located on each module for setting the current limits for each module. A control module is provided connected to the backplane.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims benefit of U.S. Provisional Patent Application Ser. Nos. 60/760,598, filed Jan. 20, 2006, and 60/762,915, filed Jan. 27, 2006, which applications are hereby incorporated by reference in their entirety. 

   FIELD OF THE INVENTION 
   The present invention relates to a power distribution panel with circuit element modules. 
   BACKGROUND OF THE INVENTION 
   Electrical circuit panels such as power distribution panels typically include a number of different circuit elements such as fuse holders and fuses, circuit breakers, input and output connectors and alarm signal LED&#39;s. For safety and other reasons, the electrical circuits of power distribution panels are enclosed within a housing structure. Therefore, the circuit elements listed above have typically been inserted into holes that have been pre-cut or pre-punched into the housing structure, usually on a front or back panel of the housing structure. 
   These prior circuit panels are fixed and once the holes are formed in the housing, the type and arrangement of the components is limited. In order to manufacture different fixed circuit panels of the prior systems, a circuit panel manufacturer would punch out different patterns of holes in the front or back panels of the housing structure in order to accommodate different arrangements of circuit elements. Significant retooling time and costs are involved for offering different fixed panels. Assembly of the circuit elements is also difficult when the elements are inserted through holes. One solution is described and shown in U.S. Pat. No. 6,456,203. 
   In addition, such panels are hardwired between the input and output connections, and the fuse and/or breaker locations. In some panels, redundant power connections are provided, controlled by an OR-ing diode including a heat sink. These features can take up significant space within the panel. 
   There is a continued need for improved power distribution panels. 
   SUMMARY OF THE INVENTION 
   A modular power distribution system comprises a chassis; and a backplane including a power input, and a plurality of module connection locations. A plurality of modules are mounted in the chassis, each module mounted to one of the module connection locations. Each module includes: (i) an OR-ing diode; (ii) a circuit protection device; (iii) a microprocessor controlling the circuit protection device; and (iv) a power output connection location. A circuit option switch is located on each module for setting the current limits for each module. A system control module is provided connected to the backplane. 
   A modular power distribution system comprises a chassis having an open front and an interior; and a backplane positioned opposite to the open front, and including a power input, and a plurality of module connection locations. A plurality of modules are mounted in the interior of the chassis, each module mounted to one of the module connection locations. Each module includes: (i) a rear connector; (ii) a main body; (iii) a circuit protection device; (iv) a front panel; and (v) a power output connection location on the front panel. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic side view of one embodiment of a power distribution panel, with a module partially inserted into the chassis. 
       FIG. 2  is a schematic side view of another embodiment of a power distribution panel, with a module partially inserted into the chassis. 
       FIG. 3  is a schematic top view of the power distribution panel of  FIG. 1 . 
       FIG. 4  is a schematic top view of an alternative embodiment of a power distribution panel. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1 and 2 , power distribution systems  10 ,  110  are shown. Power distribution systems  10 ,  110  are modular designs including a chassis  12  and removable circuit modules  14 ,  114 . Each circuit module  14 ,  114  includes an electronic breaker  16 ,  116  for circuit protection, and a port assembly  18 ,  118  for output power distribution. 
   Chassis  12  includes a top  34  and a bottom  36 . A backplane  38 , such as a printed circuit board, provides the interconnection between modules  14 ,  114  and power input connector  26 . Preferably, a second (redundant) power input connector  27  is provided (see  FIG. 3 ). 
   Modules  14 ,  114  are received in chassis  12  through a front opening  20 . Modules  14 ,  114  can be removed through front opening  20  as desired to repair, replace or service the modules. Modules  14 ,  114  can be latched or otherwise attached to chassis  12 , as desired. 
   Modules  14 ,  114  are similar in many respects for distributing and monitoring the power in systems  10 ,  110 . Modules  14 ,  114  each include a printed circuit board  42  with circuitry for linking the input power to the output power. Modules  14 ,  114  differ in the arrangements for the power outputs at port assemblies  18 ,  118 . Module  10  includes a single power output connector  72 , such as a high power connector including a DB9-2W2 connector; whereas module  110  includes a plurality of separate power output connectors  172 , such as lower power connectors including screw terminals. 
   The electronic breakers  16 ,  116  are part of active circuit modules  14 ,  114  to replace discrete fuses and circuit breaker used in prior art power distribution panels. The end user adds, removes, or upgrades ports in the power distribution system as required by adding or removing circuit modules  14 ,  114 . 
   Each circuit module  14 ,  114  can be used as a  1 A,  2 A,  10 A, etc. breaker by setting current limit options switches  22 . For example, 2 position DIP switches could be used. Prior art panels with discrete fuses and breakers have a single trip value. Control logic  24  including microcontroller  28  monitors the output current via current sensors  30 ,  130 . If the output current exceeds the limits set by option switches  22 , microcontroller  28  will turn-off (“trip”) a breaker device  32 , which is preferably a solid-state device. The current limit set by the option switches  22  can also be overridden via a software interface from a remote terminal through a control module  40  (see  FIGS. 3 and 4 ). Microprocessor  28  is networked to an external processor through control module  40 . If a breaker device  32  is tripped due to the detection of an over current condition, microcontroller  28  will periodically re-enable breaker device  32  to see if the fault still exists. This can eliminate a service visit if the over current was caused by a momentary transient condition. 
   Microcontroller  28  provides control over breaker device  32 . This eliminates disconnects caused by source or load transients. Microcontroller  28  can also set a breaker trip point based on load monitoring over time. Microcontroller  28  is also equipped with a history file that records various conditions local to the individual circuit modules  14 ,  114 . This information is accessible via the control module  40 . 
   Microprocessor  28  can include a load dependent trip control algorithm. This option allows microprocessor  28  to set the breaker trip point for a given load based on a learning algorithm. Microprocessor  28  monitors outgoing current over time (can be a user selectable time period). Microprocessor  28  is configured to calculate a margin of error, then use the new value to create a trip value for each circuit module  14 ,  114 . For example, one circuit module  14  is used in a 30 amp circuit. However, typically the circuit only draws a 27 amp load. Mircroprocessor  28  recognizes the 27 amp load by monitoring the current load over time, then adds a margin of error (e.g., 1%-5%) to create a load dependent trip value. Therefore, the circuit will trip before 30 amps is ever drawn. Such a system prevents over fusing, and damaged equipment. 
   Low voltage disconnect (LVD) is localized to the circuit modules  14 ,  114 . Under voltage conditions are monitored by microcontroller  28  with an under voltage sensor  46 . If the voltage drops below the recommended level, microcontroller  28  will turn breaker device  32  off to disconnect the load. The same process will occur if an over voltage condition occurs. Over voltage conditions are monitored by microcontroller  28  with an over voltage sensor  48 . 
   To support redundant (dual feed) applications, the OR-ing diodes  54  are localized to the individual circuit modules  14 ,  114 . Prior art power distribution panels that used OR-ing diodes placed them in the input circuits which required very large diodes and heat sinks and created a single point of failure for the system. The arrangement of systems  10 ,  110  allows the heat dissipated by the OR-ing diodes  54  to be evenly distributed in chassis  12  preventing a localized hot spot. The noted arrangement also reduces the size of the diodes and their respective heat sinks, and eliminates the single point of failure common in prior art power distribution panels. Circuit modules  14 ,  114  can also include a temperature sensor  50  for monitoring high temperature conditions. 
   An LED indicator  62  on each circuit module  14 ,  114  provides a visual status of input and output voltage, output current, temperature, over/under voltage conditions, and breaker trip. A local reset switch  68  is also provided to reset the breaker device  32  after a trip condition has occurred. 
   In circuit module  14 , all input and output to the electronic breaker  16  is via a high current connector  18  to prevent accidental contact by service personnel. Circuit module  14  includes a front connector  72 , and a rear connector  76 . Front connector  72  connects to cable connector  82  and cable  86  for the output power. Rear connector  76  connects to chassis backplane connector  84  for input power to module  14 . The high power connector also prevents polarity reversals. 
   Front connectors  172  of circuit module  114  each connect to a power output connector  182  and cable  186 . Power output connector  182  may be a lug for screw connection to front connector  172 . 
   Systems  10 ,  110  eliminate internal wiring normally required in prior art power distribution panels. All power and signaling is confined to PCB traces, planes, and bus bars, which improves reliability and reduces assembly cost. Chassis  12  is a passive component that can be reconfigured for a variety of applications. Systems  10 ,  110  also reduce the number of connections and thermal loss associated with each connection. 
   All circuit modules  14 ,  114  in chassis  12  communicate with control module  40 . Control module  40  provides access to systems  10 ,  110  via a laptop serial or network connection for status and alarm information. Control module  40  also provides the external alarms signals common in Telco application. Access to control module  40  is through a front connector  56 , or through a rear connector  58  on a back of backplane  38 . 
   Chassis  12  in  FIG. 3  has rear input power connectors  26 ,  27 , and front accessible circuit modules  14 . A modified chassis  112  in system  10 ′ as shown in  FIG. 4  includes front accessible input power connectors  126 ,  127 . 
   Circuit modules  14 ,  114  and control module  40  can be provided with front face plates  86  to protect the interior circuit features. Ventilation holes  88  can be added through front face plates  86 , to allow for airflow through systems  10 ,  10 ′,  110  for cooling of system components. 
   The above noted panels include modular arrangements for the individual or groupings of circuits. Additional modules can be added as additional circuits are added to the system. By utilizing localized OR-ing, smaller diodes and smaller heat sinks can be used. Additional advantages arise from the localized components associated with each module. In particular, with a localized low voltage disconnect elements, there is no need for a large low voltage disconnect contactors associated with a dedicated panel. Local LED indicators show indicators for each module allowing for improved diagnostics.