Patent Publication Number: US-2011050218-A1

Title: non-contact magnetic current sensing and distribution system for determining individual power readings from a plurality of power sources

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §120 to U.S. Provisional Application Ser. No. 61/275,322, entitled “System and Method for Non-Contact Magnetic Current Sensing, Calibration, Telemetry and Distribution of Individual Power Readings from Singular or Multiple Electrical Generation Circuits” filed on Aug. 25, 2009 and owned by Amptech, Inc. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to electrical measurement and more particularly to a non-contact magnetic current sensing and power monitoring system for measuring power readings from individual power sources. 
     BACKGROUND OF THE INVENTION 
     Various systems for monitoring power monitoring and providing electrical distribution are known in the electrical power arts. In many power applications, a distribution board or panel board is a component used in an electrical supply system that divides an electrical power feed into subsidiary circuits. A protective fuse or circuit breaker is often used for each circuit that is contained in a common enclosure. In some cases, a main switch or residual-current device (RCD) can also be incorporated in the system for controlling over voltages and currents. 
     In power applications, conventional methods of sensing current often uses a series dropping resistor where a voltage is measured across the resistance and used in combination with ohm&#39;s law to determine current flow. One drawback of this approach is that it requires physical connection to determine current. Moreover, some nominal power loss also occurs due to the resistance placed in series with the circuit. Still other more sophisticated methods use magnetic Hall current sensing that requires that a current sensed wire be placed inside a magnetic sensor core. This type of physical connection is difficult to install and service making it undesirable for field applications. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. 
         FIG. 1  is a top view illustrating the layout of components used in connection with an embodiment of the present invention. 
         FIG. 2  is a top view illustrating the electrical current flow direction of the components used in an embodiment of the present invention. 
         FIG. 3  is a top view illustrating the printed circuit board outline illustrating sensor position of the current invention. 
         FIG. 4  is a block diagram illustrating a wireless system configuration using the non-contact magnetic current sensing and distribution system according to another embodiment of the invention. 
     
    
    
     Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and apparatus components related to a non-contact magnetic current sensing and distribution system. Accordingly, the apparatus components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
     In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. 
     It will be appreciated that embodiments of the invention described herein may be comprised of one or more conventional processors and unique stored program instructions that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of a non-contact magnetic current and distribution system described herein. The non-processor circuits may include, but are not limited to, a radio receiver, a radio transmitter, signal drivers, clock circuits, power source circuits, and user input devices. As such, these functions may be interpreted as steps of a method to perform a non-contact magnetic current and distribution system. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic. Of course, a combination of the two approaches could be used. Thus, methods and means for these functions have been described herein. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation. 
       FIG. 1  is a top view illustrating the position and layout of components used in connection with the non-contact magnetic current sensing and distribution system according to an embodiment of the present invention. The system  100  includes an outer waterproof enclosure  101  where an inner panel  103  is fastened to an inside perimeter of the waterproof enclosure  101 . This arrangement allows the inner panel  103  to be easily separated from the waterproof enclosure  101  if replacement or service is needed without removing the waterproof enclosure  101  from a wall or other rigid structure. A plurality of multiple electrical inputs each include a plurality of input fuse holders  104 , 105  that are positioned in two parallel columns at a top section of the inner panel  103 . These holders  104 ,  105  are connected to power generation sources such as solar cells, batteries, generators or other power generating devices and are arranged in a manner so that they resemble teeth in a hair comb. This arrangement of input power input strings connect to fuse holders  104 ,  105  that work to form a conductive bank or “comb”  107 . The electrical comb  107  includes a center conductive member  109  that is used as an electrical bus for connecting to other electrical circuits at its lower end. Thus, the comb  107  electrically connects to each fuse holder  104 ,  105  to a single output lug  111  located at the lower portion of the center conductive member  109 . Further, located in a lower portion of the inner panel  103 , a return connection block  113  includes an output lug  115  and is used for providing a return circuit connection. An electrical isolator  117  is also mounted to the connection block  113  for both electrically insulating and isolating the return connection block  113  from inner panel  103 . 
     Located adjacent to the return connection block  113 , a ground connection block  119  is used for providing an earth ground through ground lug  121  to the inner panel  103  and electrical components therein. An insulator  127  provides isolation as well as a physical barrier between the comb  107 , the electrical isolator  117  and ground connection block  119 . An insulator  127  also operates to minimize inadvertent contact between the single output lug  111 , output log  115  and ground lug  121 . As described herein, an electronic module  123  is powered solely from the power sources and connects with the single conductive comb  107  for measuring each individual circuit current, the string voltage, ambient temperature and humidity. This data can then be transmitted to a web-enabled coordinator and/or computer system for processing and subsequent analysis. Further, a module fuse located in fuse holder  125  protects the electronic module  123  from current overload. 
       FIG. 2  is diagram illustrating the direction of electrical current flow for the components as shown in  FIG. 1 . The current flow diagram  200  shows a first input current path  201  and second input current path  203  that enter each fuse holder  104 ,  105  respectively. The wired connection enters a electrical fuse (not shown) located in each fuse holder  104 ,  105  and exits the fuse holder  104 ,  105  into the comb  107 . All single current generation inputs are combined into a single high current conductor  205  that carries the sum of each individual currents at output lug  123 . As will be evident to those skilled in the art, the comb geometry consists of parallel current paths  201 ,  203  for each fused input circuit. Each single current path  201 ,  203  produces a magnetic field perpendicular to the current path. The total magnetic field strength is directly proportional to the amount of current flowing in each of the input conductors. 
     As described herein, an electronic module (not shown) using one or more Hall sensing devices (not shown) is used for accurately measuring each of the individual magnetic fields produced by the current flowing through each input conductor. In use, the electronic module can be powered solely from the power generation sources without the use of power from electrical mains. The Hall sensing devices are proximity devices and are located adjacent to the input conductors without the need for each conductor to pass through a current sensor or making a direct electrical connection. Thus, these non-contact current measurements can be more easily determined yet still allowing the module to be removed for later replacement or servicing. The current return path  207  uses a conventional multiple connection block  113  with an integrated high current lug  115  that is electrically isolated from the inner panel  103 . In use, the earth ground path also includes a conventional multiple connection block  119  with an integrated high current lug  121  that is electrically connected to the inner panel  103  and an earth ground (not shown). 
       FIG. 3  is a top view of the printed circuit board illustrating the configuration of the sensor module used in  FIG. 1 . The printed circuit board  300  uses the electronic module  123  that is mechanically fastened to the topside of the comb  107  with fastener  301 . Multiple Hall sensing elements  302 ,  303  are proximity devices that are positioned adjacent to the current carrying conductive circuits. Printed circuit board  305  is used with the Hall sensing elements  302 ,  303  so that the printed circuit board  305  electrically connects Hall sensing elements  302 ,  303  to other electronic elements such as a microprocessor, transceiver and/or power supply components (not shown). One Hall sensor  307  may also be configured to measure the total current through the output lug  111  as shown in  FIG. 1 . The entire circuit can then be hermetically sealed for protecting the electronic module  123  from harsh weather conditions or airborne contaminants. 
     Finally,  FIG. 4  is a block diagram illustrating a wireless communications system configured using the non-contact magnetic current sensing and distribution system as shown in  FIGS. 1-3 . The wireless system configuration  400  utilizes a microprocessor  409  along with control software for determining the magnetic from each of the magnetic field sensors  303 . Thus the current information from the individual power generation sources  415  that is supplied through the conductive comb  107  can be readily conveyed for analysis using a wireless transceiver  411 . Moreover, simplified field calibration can more easily be performed using this data without the use of the additional field instrumentation. 
     In operation, a power supply  401  efficiently converts a small portion of the unregulated power from the fuse inputs on the conductive comb  107  to a regulated voltage capable of powering the voltage and temperature sensors  403  as well as other electronics in the non-contact magnetic current sensing and distribution system  100 . A wireless transceiver  411  provides a radio frequency (RF) wireless link for providing two-way RF data communication from the electronic module  123  via the wireless link to a web enabled remote coordinator  417 . The microprocessor  409  monitors the transceiver  411  and receives data from the magnetic sensors  303 . The microprocessor  409  provides functions such as applying calibration settings  407 , calculating current readings from the magnetic sensors  303  and measuring string voltage for each power generation source. Also, the microprocessor can also determine the temperature of the sensor module as well as temperature sensors  403  and can transmit these values to a web based coordinator  417  via the transceiver  411 . Optionally, the software can also facilitate a simplified push button field calibration  405  without the use of additional instrumentation. The web enabled coordinator  417  can send a data request code to one or more of the transceiver modules for interrogating its operational status. Upon receipt of a valid request, the microprocessor  409  measures individual sensor current, string voltage of the power sources from the conductive comb  107  and the module temperature and transmits this data back to coordinator  417  for global retrieval of information and data over the Internet and/or world wide web  419 . Multiple modules may be accessed with all data being capable of being stored or archived  421  for future use. 
     Thus, the present invention is a system to monitor and report via telemetry single or multiple electrical current and voltage readings flowing from a source to a load. This invention is especially suited, but not limited to alternative energy measurement, metrology and management. This invention embodies an electrical distribution box employing non-contact current measurement of multiple circuits with wireless two way data telemetry link to a web enabled coordinator. Multiple electronic modules can be accessed with all data available from each to the coordinator. 
     In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.