Abstract:
An apparatus and method relates to managing and controlling a photovoltaic system, especially for the safety, maintenance, alert of theft, and connection failure of the system. It is more specially for cases during the night time when the panel is not generating electricity. The present disclosure provides: an AC panel, an inverter; a communication circuit in a panel inverter to send and receive signals, a control circuit, a communicator and a power line communication method between communicator and panel inverters. The communicator detects an identification of each panel to identify the panels and collect data from each panel. The communicator is connected to the Internet through a web gateway. The apparatus also has a web based managing system to collect data from the communicator, as well as transmit signals to the communicator.

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATIONS 
       [0001]    The instant patent application converts and claims priority to U.S. Provisional Patent Application No. 61/336,200 filed on Jan. 19, 2010 to Luo et al., entitled “A Method of Managing a Photovoltaic System” which is herein incorporated by reference in its entirety. The instant patent application also converts and claims priority to U.S. Provisional Patent Application No. 61/279,130 filed on Oct. 15, 2009 to Luo, entitled “Detecting Fault in Solar Panel and Inverter” which is herein incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present disclosure relates to a method of managing and controlling a photovoltaic system. More particularly, the present disclosure includes a controller to control the panels especially for safety, maintenance, security and failure of the system. 
       BACKGROUND OF THE RELATED ART 
       [0003]    Producing power from solar energy involves installing multiple solar panels and transforming the sun&#39;s rays into electricity. Over time, the solar panels and inverters tend to become faulty due to various factors. For example, shading, snow or dust cause fault of the panels&#39; productivity. A faulty inverter may also impair a solar array&#39;s power and productivity. As result, a solar panel and inverter requires constant monitoring and maintenance to ensure normal operation. Also, the solar panel may be stolen and removed from operation. 
         [0004]    In general, detecting and correcting a fault of a solar panel and inverter in a solar array can be a very complicated. This particularly occurs when the array has large amount of solar panels. It is even more complicated to locate and identify the type of fault without a physical inspection, which is very costly. There are solutions of detecting fault of array by comparing operation profile with stored reference profile. However, the operation profile is strongly depending on many conditions, such as time, season and climate, which can affect the detection. Due to the complexity of these numerous conditions, the need of reference profiles and the need of generating reference profiles, as well as the comparison with parameters with reference profiles, this process can be very complicated and the result could be inaccurate. 
         [0005]    Accordingly, there exists a need for a method and apparatus to conveniently, quickly, and accurately manage a solar panel and solar array from a remote location and that prevents theft of components of a system. 
       SUMMARY OF THE INVENTION 
       [0006]    It is the object of the present disclosure to find a low cost monitoring and control method for photovoltaic system with panel inverters, more specifically for safety control, theft and failure detection. It is more specially for cases during the night time when the panel is not generating electricity. 
         [0007]    The disclosure relies on the several factors: 
         [0008]    1. Each panel has an inverter, which is named panel inverter here. 
         [0009]    2. Panel inverter is attached to panel so tight that any separation will damage the panel. E.g. panel inverter is attached to the back surface of the panel by adhesive; inverter is attached to panel frame by rivets. The combination of panel and panel inverter is named AC panel. 
         [0010]    3. There are 2 output AC cables for each AC panel, but connected inside of inverter. Each AC cable has multiple wires inside. The wires are connected together inside inverter. The output of power conversion circuit is connected to the output wires. 
         [0011]    4. There is communication circuit inside panel inverter, which is connected to output cables to send and receive signals. Communication circuit also send signal to control circuit. 
         [0012]    5. In a photovoltaic system, the outputs of panel inverters are connected in series and then to AC power line, electric panel, and AC outlet. 
         [0013]    6. A communicator is plugged into AC outlet. 
         [0014]    7. Data is transferred between communicator and panel inverters through a power line communication method. 
         [0015]    8. The communicator detects ID of each panel to identify them and collect data from each panel. 
         [0016]    9. The communicator is connected to internet through web gateway. Web based managing system collect data from communicator, as well as send signal to the communicator. 
         [0017]    10. The communicator can send signal through power line to all panel inverters to communication circuit and then control circuit. 
         [0018]    When there is a need to maintain solar system, user can input command in the web system, the system will send a command to data communicator, which will send a signal to panel inverter control circuit to stop the operation of the inverter. As result, even though solar panel is still generating DC power, there is no AC current/voltage output from the inverter. It is safe for people to approach or maintain the system. 
         [0019]    When there is a theft, as the panel inverter is attached to panel solidly with anti-theft method, they have to disconnect the panel inverter from the cables. Since the AC cables are connected in series to form the power line, the disconnection breaks the power line. As each panel and inverter communicate with communicator power line, the break will terminate the data communication from all panels beyond it. The managing system will detect and localize the open, send signal to alarm, show alert message, or send alert to any mobile devices. 
         [0020]    This feature works the same way when there is failure in cable connection, which is one of most popular failure modes. 
         [0021]    According to a first aspect of the present disclosure, there is provided a method of detecting a parameter in a solar panel array. The method comprises providing a first signal from a first solar panel to a remote entity with the first solar panel being connected to a second solar panel and providing a second signal from the second solar panel to the remote entity. The method infers that at least one solar panel has been removed from the array when at least one of the first or second signal is interrupted to the remote entity. 
         [0022]    In yet another aspect of the present disclosure there is provided an apparatus for detecting a parameter of a solar panel array comprising a first solar panel providing a first signal from the first solar panel to a remote entity. The first solar panel is connected to a second solar panel. The second solar panel provides a second signal from the second solar panel to the remote entity. The apparatus also has a device connected to the first and the second solar panel. The device infers that at least one solar panel has been removed from the array when at least one of the first or second signal is interrupted to the device. 
         [0023]    In another embodiment of the present disclosure, there is provided a method of safely shutting down operation of a solar panel array comprising providing a first solar panel connected to a first inverter. The first inverter comprises at least one of a control circuit, a power conversion circuit, a monitoring circuit and a communication circuit. The method provides a second solar panel connected to a second inverter with the second inverter comprising at least one of the control circuit, the power conversion circuit, the monitoring circuit and the communication circuit. The method provides a managing system connected to the first and the second solar panels. The method controls at least one component of the first or the second inverter to shut down operation of the solar panel array. 
         [0024]    According to yet another embodiment of the present disclosure there is provided a safety device comprising a first solar panel being connected to a first inverter with the first inverter comprising at least one of a control circuit, a power conversion circuit, a monitoring circuit and a communication circuit. The device also has a second solar panel connected to a second inverter with the second inverter comprising at least one of the control circuit, the power conversion circuit, the monitoring circuit and the communication circuit. The device also has a managing system connected to the first and the second solar panels. The managing system controls at least one component of the first or the second inverter to shut down operation of the solar panel array. 
         [0025]    According to another aspect of the present disclosure, there is provided an inverter comprising: a control circuit, a power conversion circuit, a monitoring circuit and a communication circuit, the communication circuit providing a signal to a remote entity, wherein the remote entity infers a condition when the signal is interrupted. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0026]    The foregoing and other objects, features and advantages of the disclosure will be apparent from the following more particular description of preferred embodiments of the disclosure, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout different views. The drawings are not meant to limit the disclosure to particular mechanisms for carrying out the disclosure in practice, but rather, are illustrative of certain ways of performing the disclosure. Others will be readily apparent to those skilled in the art. 
           [0027]      FIG. 1A  shows an illustration of a photovoltaic DC panel  100 ; 
           [0028]      FIG. 1B  shows an illustration of a photovoltaic panel inverter  100 ′; 
           [0029]      FIG. 1C  shows an illustration of a photovoltaic AC panel  100 ″, comprising of DC panel  100  and panel inverter  100 ′; 
           [0030]      FIG. 2  is a block diagram of a photovoltaic panel inverter; 
           [0031]      FIG. 3  shows an illustration of a photovoltaic system, comprising AC panel, AC cable, electric panel, AC outlet, power line, communicator, web gateway and managing system; 
           [0032]      FIG. 4  shows an illustration of a safety feature of the photovoltaic system; 
           [0033]      FIG. 5  shows an illustration of the data communication flow of the photovoltaic system when the panel inverters send data to the web managing system; and 
           [0034]      FIG. 6  shows an illustration of feature to monitoring the theft or open failure of cable connections. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0035]    The present disclosure provides a method of detecting a parameter in a solar panel array  3011 ,  3012 , and  3013  ( FIG. 4 ). The method comprises providing a first signal from a first solar panel  3011  to a remote entity  310  with the first solar panel  3011  being connected to a second solar panel  3012  and providing a second signal from the second solar panel  3012  to the remote entity  310 . The method infers that at least one solar panel  3011  or  3012  has been removed from the array when at least one of the first or second signal is interrupted to the remote entity  310  as shown in  FIG. 4  and as will be discussed herein. The remote entity  310  can control an alarm or the like or otherwise control the array or can control components that control components of the array to perform various advantageous functions. Also in another embodiment, the remote entity  310  can perform an emergency shut down procedure when needed. 
         [0036]      FIG. 1  shows an illustration of a photovoltaic DC panel  100 , comprising of panel  101  with plurality of solar cells, DC cables  102 , and connectors  103 . The panel  101  of the solar cells is electrically connected to DC cables  102  and connectors  103  as shown. It should be appreciated that the panel  101  may comprise at least one solar cell, two solar cells or more than two solar cells and various configurations are possible and within the scope of the present disclosure. 
         [0037]      FIG. 1B  shows an illustration of a photovoltaic panel inverter  100 ′, comprising of input DC cables  106 , input cables DC connectors  105 , inverter  104 , output AC cables  107 , and AC cable connectors  108 . Preferably, the DC input cable connectors  105  are connected to the input DC cables  106 , which are connected to the inverter  104 . Inverter  104  is connected to output DC cables  107 , which are connected to the AC cable connector  108 . It should be appreciated that the configuration of the inverter panel  100 ′ is not limiting and the present panel  100 ′ may include a different configuration than shown herein. 
         [0038]      FIG. 1C  shows an illustration of a photovoltaic AC panel  100 ″, comprising of DC panel  100  and panel inverter  104 . The connectors  103  of DC panel  100  of  FIG. 1A  and input connectors  105  of  FIG. 1B  of panel inverter  104  are connected together as shown in  FIG. 1C .  FIG. 1C  shows the panel  101  being connected to DC cables  102 , which are connected to connectors  103 , which are connected to DC input cable connectors  105 . DC input cable connectors  105  are connected to input DC cables  106 , which are connected to the panel inverter  104 , which are connected to the output DC cables  108  and which are then connected to AC cable connector  108 . It should be appreciated that the configuration of the DC panel  100 ″ is not limiting and the present panel  100 ″ may include a different configuration than shown herein. 
         [0039]      FIG. 2  is a block diagram of a photovoltaic panel inverter  104  shown in  FIGS. 1B and 1C . Inverter  104  is connected to input DC cable  106 . The inverter  104  includes, but not limited to: a power conversion circuit  201 , a control circuit  202 , a monitoring circuit  203 , and a communication circuit  204 . 
         [0040]    The power conversion circuit  201  converts DC current from input DC cable  102  shown in  FIG. 1C  into AC current at output  206 . The power conversion circuit  201  is connected to terminal  210  through an output  206 . The monitoring circuit  203  monitors signals at a DC input through an input  205 . The monitoring circuit  203  monitors signals such as current, and voltage via input  205 . The monitoring circuit  203  monitors signals at an AC output through an output  207 , such as current, voltage, frequency, etc. The monitoring circuit  203  sends data to the communication circuit  204 . The communication circuit  204  is connected to a terminal  210  through a communication path  209  (wired path or wireless path via an RF element). The terminal  210  is connected to the output cables  107  of inverter  104 . The communication circuit  204  communicates data out of inverter  104  though the path  209 , the terminal  210 , and the output cables  107 . 
         [0041]      FIG. 3  shows an illustration of a photovoltaic system, comprising AC panel  301 , AC cable  303 , the electric panel  304 , an AC outlet  305 , a power line  306 , a communicator  307 , a web gateway  309  and a managing system  310 . Preferably, the AC panel  301  is connected to the AC cable  303 . AC cable  303  is connected to the electric panel  304 , which is connected to the power line  306 . Power line  306  is connected to the AC outlet  305 , which is connected to a line  308 . Line  308  is connected to the communicator  307 . Communicator  307  includes a bidirectional communication path to the web gateway  309 , which also has a bidirectional communication path to the managing system  310 . 
         [0042]    A plurality of AC panels  3011 ,  3012 ,  3013  . . .  301 N are connected in series by connecting the AC cable connectors  108  to form a string generally represented by reference numeral  302 . Preferably, AC panel  3011  is connected to AC panel  3012  and so on. Due to the connection method of the AC cable  107  shown in  FIG. 2  and the power conversion circuit output  206  shown in  FIG. 2 , for the string  302  of AC panels  301  (shown in  FIG. 3 ), the power conversion circuit outputs  206  ( FIG. 2 ) are connected into the AC cable  303  ( FIG. 3 ) in parallel. 
         [0043]    One end of the AC cable  303  of the string is connected into the electric panel  304  through the AC cable  303 , and the AC outlets  305  through power line  306 . At the other end of the string, the cable connector is covered by a cap  311  as protection and insulation. 
         [0044]    Turning now again to  FIG. 3 , a communicator  307  is shown. Communicator  307  is shown plugged into the AC outlet  305  through the power cord  308 . By a power line communication method, the communicator  307  communicates with the AC panel  301  through the power cord  308 , the electric panel  304 , the AC outlet  305 , the power line  306 , and the AC cables  107  shown in  FIG. 2 . The communicator  307  is also connected to the web gateway  307  by an Ethernet connection, Wi-Fi, Wi-Max, Bluetooth™, or via other wireless, or similar methods known in the art. Through the web gateway  309 , a web based managing system  310  collects the system information from the communicator  307  and perform storage, analysis, presenting, graphing, and other functions. Managing system  310  also sends a signal to communicator  307  and then to the AC panels  3011 ,  3012 , etc. 
         [0045]      FIG. 4  shows an illustration of a safety feature of the photovoltaic system. When user wants to maintain or wants to quickly shutdown the system for an emergency the AC panel will still generate AC voltage and current, which causes risks to the person approaching the system. This occurs even if grid connection is shut off by electric panel  304 , and if there is sun on the panel, then the AC panel will still generate AC voltage and current, which causes risks to the person approaching the system. The present disclosure introduces a safety feature to shutdown panels, which is advantageous. 
         [0046]    A command is input from managing system  310 . The signal  401  is transferred through the web gateway  309 , the communicator  307 , the power cord  308 , the AC outlet  305 , and the power line  306 . The signal  401  shown by arrow will then traverse to the electric panel  304 , the AC cable  303 , and the panel AC cables  107  shown in  FIG. 2  into AC panel  301 . The communication circuit  204  in the panel inverter  104  ( FIG. 2 ) receives the signal through the path  209  ( FIG. 2 ) and sends a signal through the path  208  ( FIG. 2 ) to the control circuit  202  ( FIG. 2 ) to shut down the power conversion circuit  201  ( FIG. 2 ) and then the output  206  ( FIG. 2 ) of the AC panel  301  ( FIG. 4 ). This feature eliminates the danger of exposure to a high voltage AC for maintenance person, users, servicers, police, and fireman, etc. It should be appreciated that in an alternative embodiment, the communication circuit  204  may receive the signal via a different wireless or wired method than shown herein. For example, using a transceiver or the like the managing system  310  of  FIG. 4  may directly communicate with the communication circuit  204  of  FIG. 2  or some of the elements shown may be eliminated and connected differently. 
         [0047]      FIG. 5  shows an illustration of the data communication flow of the photovoltaic system when the panel inverter(s)  104  ( FIG. 2 ) send data to the web managing system  310  ( FIG. 5 ). It should be appreciated that the number of inverters  104  sending data can be one inverter  104  or more than one inverter  104  and various configurations are possible and within the scope of the present disclosure. The monitoring circuit  203  ( FIG. 2 ) in panel inverter  104  ( FIG. 2 ) collects data, such as current, voltage, frequency, temperature, etc, and sends the signal to communication circuit  204  ( FIG. 2 ) in the inverter  104  ( FIG. 2 ). The communication circuit  204  ( FIG. 2 ) sends the data  501  ( FIG. 5 ) through the AC panel cables  107  ( FIG. 2 ) into the string AC cable  303  ( FIG. 5 ) and then into electric panel  304  ( FIG. 5 ). The signal shown by arrow is then communicated through the power line  306  ( FIG. 5 ) into the AC outlet  305  ( FIG. 5 ). The data then passed into the communicator  307  ( FIG. 5 ) through the power cord  308  ( FIG. 5 ). The communicator  307  ( FIG. 5 ) sends the data to the web gateway  309  ( FIG. 5 ), and then into the internet based managing system  310  ( FIG. 5 ). 
         [0048]      FIG. 6  shows an illustration of the feature to monitor the theft or to monitor the failure or otherwise removal of one component of the system. The component preferably can be a solar panel  101  as shown in  FIG. 1A  or can be any component of the system and is not limited to the solar panel  101 . As an example, when the AC cable connection between the AC panel  3012  and the AC panel  3013  is broken as shown as break  601  due to theft or due to a part failure, the data communication flow of the photovoltaic system stops at the panel  3012  and the AC panel  3013  does not communicate along the break  601 . As the managing system  310  ( FIG. 6 ) monitors the data from each individual AC panel  3011 ,  3012 ,  3013 , and  301   n  ( FIG. 6 ), when the managing system  310  ( FIG. 6 ) only receives data as shown by arrow  5011  managing system  310  ( FIG. 6 ) from the AC panel  3011  and data as shown by arrow  5012  from the AC panel  3012 , and when the managing system  310  does not receive data that it usually would receive from elements  3013  and  3013   n  in the form of arrows  5013 - to  501 N not shown, the managing system  310  infers that there is a break between the AC panel  3012  and the AC panel  3013  ( FIG. 6 ). The managing system  310  ( FIG. 6 ) will turn on an alarm, or show an alert message, or even send an alarm to mobile devices. The managing system  310  ( FIG. 6 ) preferably provides some audible alarm to indicate the removal of the component. This managing system  310  ( FIG. 6 ) feature works even when the panels  3011  through  301 N are not generating electricity, such as during night time hours or even when the panels  3011  through  301 N covered. 
         [0049]    In a less preferable embodiment of the present disclosure, the solar panels may not provide a continuous signal to the managing system  310 . In this less preferable embodiment, a signal from a solar panel inverter  104  may only be provided when a solar panel next to the removed solar panel is removed to the managing system  310 . In this instance, the managing system  310  would infer that the adjacent solar panel has been removed upon receiving the signal. 
         [0050]    Referring again to  FIGS. 1-6  certain aspects of the system and components thereof may be implemented on a computer system. The computer system preferably includes the generic components of most general purpose computers. The computer system comprises an interconnection mechanism such as a bus or circuitry which couples an input device such as a keyboard. The system also has a processor (such as a microprocessor having an arithmetic logic unit, a register and a control unit). The computer also includes a storage device or memory (such as a computer disk for a main memory and secondary storage) and an output device such as a monitor or screen. The computer also has a network connection for connecting to the Internet. Various embodiments of the disclosure will be described in conjunction with the components of computer systems. A typical example of a computer system is an IBM® Personal Computer, an APPLE® MAC® computer, or a compatible computer. 
         [0051]    Generally, in operation, the computer system operable with that method shown in  FIGS. 1-6  is controlled by an operating system. Typical examples of operating systems are MS-DOS and Windows95 from Microsoft Corporation, or Solaris and SunOS from Sun Microsystems, Inc., or the Apple OSX from Apple Corporation. As the computer system operates, input such as input search data, database record data, programs and commands, received from users or other processing systems, are stored on storage device. Certain commands cause the processor to retrieve and execute the stored programs. The programs executing on the processor may obtain more data from the same or a different input device, such as a network connection. The programs may also access data in a database for example, and commands and other input data may cause the processor to index, search and perform other operations on the database in relation to other input data. Data may be generated which is sent to the output device for display to the user or for transmission to another computer system or device. Typical examples of the computer system are personal computers and workstations, hand-held computers, dedicated computers designed for a specific purpose, and large main frame computers suited for use many users. The present disclosure is not limited to being implemented on any specific type of computer system or data processing device. 
         [0052]    It is noted that the present disclosure may also be implemented in hardware or circuitry which embodies the logic and processing disclosed herein, or alternatively, the present disclosure may be implemented in software in the form of a computer program stored on a computer readable medium such as a storage device. In the later case, the present disclosure in the form of computer program logic and executable instructions is read and executed by the processor and instructs the computer system to perform the functionality disclosed as the disclosure herein. If the present disclosure is embodied as a computer program, the computer program logic is not limited to being implemented in any specific programming language. For example, commonly used programming languages such as C, C++, JAVA as well as others may be used to implement the logic and functionality of the present disclosure. Furthermore, the subject matter of the present disclosure is not limited to currently existing computer processing devices or programming languages, but rather, is meant to be able to be implemented in many different types of environments in both hardware and software. 
         [0053]    Furthermore, combinations of embodiments of the disclosure may be divided into specific functions and implemented on different individual computer processing devices and systems which may be interconnected to communicate and interact with each other. Dividing up the functionality of the disclosure between several different computers is meant to be covered within the scope of the disclosure. 
         [0054]    While this disclosure has been particularly shown and described with references to a preferred embodiment thereof, it will be understood by those skilled in the art that is made therein without departing from the spirit and scope of the disclosure as defined by the following claims.