Abstract:
Method, apparatus and system for converting or redirecting use of any inverter or uninterruptable power supply (UPS) with the help of the proposed Solar Management Unit (SMU) into a standalone or off-grid solar system of equivalent capacity solar power. The SMU simplifies the system design to utilize existing investment in an inverter and other equipment and reduces solar system installation time.

Description:
PRIORITY CLAIM 
       [0001]    This patent application claims the benefit of the U.S. provisional patent application having Ser. No. 61/595,075, filed Feb. 4, 2012; the aforementioned application being incorporated by reference in its entirety. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    Embodiments disclosed herein relate to a system, apparatus and method of converting or redirecting use of any inverter based backup power supply or uninterruptable power supply with the help of the described herein solar management unit (SMU) into a standalone (i.e., off-grid), grid tied or grid tied bidirectional solar system powered by solar power. 
       BACKGROUND 
       [0003]    A simple inverter based back up power supply system uses an inverter with a battery to supply AC power when mains (or grid) power is not available. An inverter is an electrical power device that converts direct current (DC) to alternating current (AC). Inverters are used in a wide range of applications and commonly used to supply AC power from DC sources such as batteries. Such a system  100  is shown in  FIG. 1A  and includes battery  102  and inverter  104 . Adding a solar source to this system would allow for renewable backup power. A solar power system  120  as illustrated in  FIG. 1B  shows the addition of a solar source to a battery backup system and includes the following major components: solar panel(s) or module  122 , charge controller  124 , battery  126 , and inverter  128 . A driven load may receive AC power from the solar array  122  or the battery  126  in case of failure of the main power supply. While this system  120  is greener than the system of  FIG. 1A , it still does not optimally produce power from a solar source. 
       SUMMARY OF THE INVENTION 
       [0004]    In an aspect of the disclosure herein: a method of integrating a solar panel into a backup power supply system comprising: connecting a solar management unit (SMU) to a pre-existing backup power system including a battery, inverter and AC mains power; connecting at least one solar panel to the SMU; performing an initialization process wherein the SMU detects the capacity of the battery, inverter and solar panel; and determining which of the AC mains power or solar panel will charge the battery. 
         [0005]    In another aspect of the disclosure herein: A solar management unit (SMU) comprising: a processor with a memory; a plurality of terminals located on the SMU allowing the SMU to be able to receive and provide output to an inverter and at least one battery; a solar charge controller configured to receive input from a solar panel and in communication with the processor; a first controlled switching element in is communication with the processor and directed by the processor to turn on or off AC mains power availability; and a second controlled switching element also under control of the processor and in connection with the solar charge controller to turn on or off battery charge output. 
         [0006]    In another aspect of the disclosure herein: a solar management unit (SMU) comprising: a processor with a memory, wherein the processor is configured to receive capacity condition measurements of a plurality of elements connected to said SMU; a plurality of terminals located on the SMU allowing the SMU to be able to receive and provide outputs to the plurality of elements including an inverter and at least one battery; a solar charge controller including an MPPT configured to receive input from a solar panel and in communication with the processor; a first controlled switching element in communication with the processor and directed by the processor to turn on or off AC mains power availability; a second controlled switching element also under control of the processor and in connection with the solar charge controller to turn on or off battery charge output; and wherein the processor is further configured to prioritize directing that power be provided to a load based on a predetermined sequence. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIGS. 1A and 1B  illustrate prior art UPS and solar power systems. 
           [0008]      FIG. 2A  illustrates a control system for controlling an output of a solar panel in accordance with a first embodiment. 
           [0009]      FIG. 2B  illustrates a control system for controlling an output of a solar panel in accordance with a second embodiment. 
           [0010]      FIG. 3  represents an overview block diagram of the SMU  202  which can be used for both the system as disclosed in  FIG. 2A  and  FIG. 2B . 
           [0011]      FIG. 4  shows the internal design of the SMU used when the system of  FIG. 2A  is implemented. 
           [0012]      FIG. 5  is a detailed illustration showing the internal design of the SMU when the system of  FIG. 2B  is implemented. 
           [0013]      FIG. 6  represents an alternative overview block diagram of the SMU  202 . 
           [0014]      FIG. 7  illustrates a method of operation of a typical system utilizing the SMU of this detailed description. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0015]    The embodiments described herein relate to a system, apparatus and method of converting or redirecting use of any inverter based backup power supply system or uninterruptable power supply (UPS) system with the help of a described solar management unit (SMU) into a standalone (i.e., off-grid), grid tied or grid tied bidirectional solar system powered by solar power. There is a significant installed base in the market of inverters as well as UPS systems for backup using a diesel generator or battery storage as a second source. One disadvantage of diesel generators is that they lead to polluting of the environment. The SMU described herein allows for an inexpensive way to convert an inverter based backup supply systems or UPS systems to work as a solar power system while using an existing inverter and battery (or batteries). 
         [0016]    One of the issues when using solar power as a source is the temperature levels at the solar panels. A solar panel&#39;s operating point (voltage and current) may be determined by an electronic circuit called a maximum power point tracker (“MPPT”). As the temperature increases, the MPPT drifts to produce a lower energy output. The V oc , or open circuit voltage, reduces significantly and I sc , or short circuit current, increases marginally. As a result, the battery behavior in the solar source system is also impacted by the operating temperature. Currently, MPPT based solar systems do not provide for temperature compensation. Thus, when solar panel temperature increases and the V oc  drops, and the panel works at new maximum power point voltage (V MPP ) and maximum power point current (I MPP ) values. A solar system circuit including an SMU as described herein will compensate for the change in the temperature and provide correction for reducing solar panel stress. 
         [0017]    For example, in a first embodiment shown in  FIG. 2A  shows what was originally just a UPS system with an inverter connected to a battery and to AC mains power converted to a solar power system with the addition of a solar panel  226  and an SMU  202 . In operation of this solar power system  200 , the load is normally connected to mains power and solar power is used to charge the batteries. When mains power fails, the system switches so that the load is driven by a battery (or batteries) through the inverter. There are a plurality of internal SMU configurations which may be used in accordance with the preferred embodiments described herein that are differentiated by architectures, internal circuits, power ratings and priorities of various power sources. The configuration of the SMU  202  can also be based on various internal solar charge controllers such as a MPPT, MPPT with maximum current point tracking (MPCT), pulse width modulation (PWM), or other types of charge controllers. As discussed above, an MPPT charge controller is designed to maximize harvest and storage of harvested power with very high conversion efficiencies of over 99% but does not properly account for temperature changes. The addition of an MPCT charge controller to an MPPT ensures that the highest possible current is transferred to the battery. Examples of such charge controllers are discussed in detail in commonly owned U.S. patent applications Ser. No. 12/643,266, filed on Jun. 24, 2010, and Ser. No. 13/095,766, filed on Oct. 27, 2011, which are both hereby incorporated by reference in their entirety. 
         [0018]    In the solar power source system of  FIG. 2A , the SMU  202  is connected to mains electricity  204  which is a general purpose AC electric power supply (also known as “AC mains” or the grid). The SMU  202  is designed to accept any type of power supply input from AC mains  204  as long it does not exceed predetermined voltages and currents. AC mains  204  power is routed through AC line  206  to a terminal on SMU  202 . AC mains power may then be connected or disconnected from the load  220  via a controlled switching element and relay (referenced as  202   d  in  FIGS. 3 to 6 ) located in the SMU  202  through AC line  208  to an inverter  210 . The SMU  202  may be designed to connect to any type of inverter  210  which accepts the standard power supply in the country of use. The system  200  can operate with an on the grid or off the grid inverter  210 . 
         [0019]    The battery terminals  202   a  of the SMU  202  may be connected via DC line  212  to the battery terminals  214   a  of a battery  214  (or, alternatively, a bank of a plurality of batteries). The original DC connection  216  in place before the addition of the SMU  202  and the solar array  226  to the system between the inverter  210  and the battery  214  may remain unchanged. Therefore, the AC mains power may be used to charge the battery  214  from mains power (as discussed below) through line  216  and the battery  214  can provide power to the load  220  through the inverter  210 . The solar panel (or, alternatively, a string of solar panels)  226  is connected via DC line  228  to the photo-n voltaic inputs  202   c  of the SMU  202 . Control and switching circuitry in the SMU  202  (as discussed in detail below) is used to relay the solar power from the panel  226  to charge the battery  214  through DC line  212 . An advantage of the present embodiment is that the SMU  202  can be connected to crystalline or thin film panels based on any technology. Also, the SMU  202  can also be connected to other power sources besides (or in place of) the solar panels  226  such as a diesel generator or a wind turbine (not shown). 
         [0020]    The SMU  202  described herein may include various functionalities and features driven by hardware and internal software programs which may be configured depending on the end application. Such control circuitry hardware may include an internal processor coupled to a memory, an integrated circuit or a microcontroller (as shown by reference numeral  202   x ) or any combination thereof. A decision tree for prioritization of energy storage as well as energy use can be programmed into a microcontroller  202   x  to implement priority options. There are at least 4 priority options or sequences that may be programmed into the control circuitry of the SMU  202  which sequence the use of solar, battery and grid for optimal power production. In one embodiment, a prioritization sequence to drive the load  220  may be starting with high priority to low priority: 
         [0021]    a. Solar→Battery→Grid 
         [0022]    b. Solar→Grid→Battery 
         [0023]    c. Grid→Solar→Battery 
         [0024]    d. Grid→Battery→Solar 
         [0025]    The SMU  202  allows for use of all possible decision sequences for charging and discharging the battery  214  and for driving load  220  priorities. Factoring into the decision on the priority options may be whether the environment switch is set as urban or rural. Also, in an alternative embodiment, sensors (not shown) may be connected to the SMU  202  that can determine the weather such as temperature and sunshine to help determine which priority option should be chosen. Also, weather criteria may be input either from the monitoring system  224  or some other control system which is remotely located. Environment mode switch (or button)  202   d  allows the SMU  202  to operate efficiently in both urban and rural environments. When the environment mode is set to urban mode, the SMU  202  is ideal for a city location where AC mains power dependency is very high. When the environment mode is set to rural mode, the SMU  202  is better suited for locations where interruption in AC mains power is quite common. In an alternative embodiment, instead of a switch (or button)  202   d  the environment mode may be changed through the monitoring system  224  which allows the mode to be controlled remotely. 
         [0026]    In a typical operation, the SMU  202  will charge the battery  214  from the solar panels  226  as a top priority though it can be directed to charge other power sources also. When the battery voltage of the battery  214  drops below a specified level which is programmed into the microcontroller  202   x  of the SMU  202 , the battery  214  may also be charged from AC mains  204  using a mains charger  210   b  located in the inverter  210  through line  216 . When battery charge level reaches a predetermined or preprogrammed level in a microcontroller  202   x,  the AC mains  204  charging will be cut off. The load  220  will be primarily driven by the inverter  210  through AC line  218  using power stored in the battery  214  or solar power from the solar panel  226  if it is available. Another option is to drive the load  220  directly by power from AC mains  204 . In this case the battery  214  will be charged by solar energy and on predetermined conditions programmed in the microcontroller  202   x,  the battery  214  will start charging using power from AC mains  204 . An advantage of the embodiments disclosed in this detailed description is that the SMU  202  can be connected to any battery or storage element which can store electrical energy and can transfer electrical energy to the load when in demand by the load controlled by any type of charge control system (i.e., MPPT, PWM, etc.). 
         [0027]    The system  200  also may include a monitoring system  224  which can be connected through a communication line  222  to direct operation of the SMU  202 . Alternatively, the monitoring system  224  can be monitored from a remote location (“remote monitoring system”). This could be subscription based Software as a Service (SAAS) implemented in a dedicated portal to manage and monitor the system  200  or a plurality of systems. For this, the remote monitoring system may be equipped with a general packet radio service (GPRS) cellular communication device (e.g., a Solcom GPRS module) to collect and transmit the data remotely. 
         [0028]    Upon being added to a new system, the SMU  202  will perform initial characterization or testing of the system. When the SMU  202  is installed and turned on, during setup the SMU  202  is programmed to identify battery  214  capacity, inverter  210  capacity and solar power capacity from the solar panel  226 . The SMU  202  will also start to collect data on the load pattern from the load  220  and will do so on a continuous basis. The data will be analyzed by the microcontroller  202   x  within the SMU  202  and will be used to optimize the source of power used to drive the load  220  and charge the battery  214 . The SMU  202  is further configured to track battery  214  status and make decisions based on an internal software program in the microcontroller  202   x.  AC mains  204  will start charging the battery  214  when the battery voltage will drop below a minimum battery charge level referred as V bmin  and AC mains  204  charging will stop charging the battery  214  when maximum battery charge level referred as Vbmax is reached. SMU  210  will detect V bmin  and V bmax  of the inverter  210 . The SMU  202  will use these parameters to set up new AC main  204  charging on and off conditions. The microcontroller  202   x  will also make decisions such as: whether the load  220  should be driven by solar or battery power; whether the power source for charging the battery  214  should come from solar or mains power supply; when AC mains  204  power supply should start charging batteries  214 ; when AC mains  204  power supply should stop charging the battery  214 ; when AC mains  204  power supply should start driving the load  220 ; and when AC mains  204  supply should stop driving load  220 . Also, the SMU  202  is further designed to measure power generation from solar panel  226 ; measure power used from AC mains  204  power supply; and send indications or results to a display or communication interface on the monitoring system  224 . 
         [0029]    In another system setup as illustrated in  FIG. 2B , system  250  is altered so that the load  220  is driven by solar power from the solar panel  226  directly through DC line  230  and when solar power is not present or the load  220  is higher than the solar power that is available, the SMU  202  will direct the system  250  to switch to battery  214 . Battery  214  will provide power through DC line  212  to the SMU  202  and through DC line  230  to the inverter  210  and then through AC line  218  to the load  220 . Battery  214  charging is turned on or off depending on the status of the battery  214  and a program stored in the microcontroller  202   x  of the SMU  202 . The battery  214  may either be charged from the solar array  226  or from AC mains power which travels through SMU  202  to the inverter  210 , is then converted to DC power and travels through DC line  230  back through the SMU  202  and on to the battery  214 . The SMU  202  architecture is such that the connection  216  running from the battery terminals  210   a  of the inverter  210  may be disconnected from the battery  214  and reconnected as the connection  230  to the terminals  202   b  of the SMU  202 . As a result the controlled battery terminal  202   a  is provided as output of the SMU  202  which will then connect to the battery  214  input terminals  214   a.    
         [0030]    The interface of the SMU  202  is designed so that the inverters, batteries and connection diagrams are simple so as to make it easy to install the SMU  202  and make appropriate wiring changes as required to complete the system installation. As previously discussed, the SMU  202  is specifically designed to be versatile and capable of converting all types of inverters or UPS systems into solar power systems. 
         [0031]      FIG. 3  represents an overview block diagram of the SMU  202  which can be inserted into both the system disclosed in  FIG. 2A  and the system disclosed in  FIG. 2B . SMU  202  includes a controlled switching element (or relay) module  202   d,  an internal SMU system module  202   e  and priority logic and switching elements module  202   f.  SMU  202  further includes a microcontroller  202   x  communicatively coupled to each of the controlled switching element module  202   d,  SMU system module  202   e  and priority logic and switching elements module  202   f.  An AC input including AC input terminal  1   202   g  provides power from AC mains  204  to SMU  202 . The microcontroller  202   x  is programmed to direct controlled switching element  202   d  through communication line  202   k  to connect the AC power to AC main out terminal  202   j  to either 1) send AC power to the inverter  210  when the load  220  is operating off AC main power or 2) charge the battery  214 . The microcontroller  202   x  may turn power from AC mains  204  on or off. SMU system module  202   e  is comprised of a solar charge controller such as MPPT, PWM (or other types of controllers) and controlling circuitry (e.g., microcontroller  202   x ). Detailed architecture and operation of internal SMU system module  202   e  will be further discussed in connection with  FIGS. 4 and 5 . Internal SMU system module  202   e  is capable of receiving power input from the solar panels  226  through terminal  202   c.  Internal SMU system module  202   e  will connect the solar power through terminal  202   m  to the priority logic and switching elements module  202   f.    
         [0032]    The microcontroller  202   x  is further programmed to direct priority logic and switching elements  202   f  through communication line  2021 . The priority logic and switching elements module  202   f  is configured to provide the battery charge  202   h  from solar panel  226  through terminal  202   a  to charge the battery  214 . In the case of  FIG. 2B , when power is required by the load  220  from battery  214 , the power is passed through connection  212  to terminal  202   a  (as shown in  FIGS. 2A and 3 ) connected by priority logic and switching element module  202   f  to terminal  202   b  and then through line  230  to the inverter  210  and then to the load  220 . Also, in the case of  FIG. 2B , when the battery  214  needs to be charged by AC mains power, power is routed from AC mains  204  through SMU  202  and inverter  210  and back to the SMU  202  as DC power to be received at terminal  202   b.  Therefore, the SMU  202  allows the load  220  to be driven by battery power (converted to AC power using the inverter  210 ) or solar power controlled by solar charge controller or AC mains power directly. 
         [0033]    Details of the plurality of internal connections and method of operation of the SMU  202  are disclosed in  FIGS. 4 and 5 . 
         [0034]      FIG. 4  shows the internal connections of the SMU  202  used when the system of  FIG. 2A  is in operation. As discussed with reference to  FIG. 3 , the controlled switching element  202  under the control of the microcontroller  202   x  determines whether AC main power is turned on or off, provided to the battery  214  and/or provided to the load  220 . The solar charge controller  202   p  located in the internal SMU module  202   e  may be (as previously addressed) an MPPT charge controller, PWM charge controller and any other charge controller depending on the type specified for the SMU  202  in terms of watt peak rating of the solar panel  226 . 
         [0035]      FIG. 5  is a detailed illustration showing the internal connections of the SMU  202  when the system of  FIG. 2B  is implemented. The controlled switching element  202  is again under the control of the microcontroller  202   x  which determines whether AC main power is turned on or off, provided to the battery  214  and/or provided to the load  220 . As in  FIG. 4 , the solar charge controller  202   e  receives the DC charge from the solar input terminal  202   c  and provides a battery charge  202   h  to the controlled switching element  202   f  and then to the battery  214  through line  212 . 
         [0036]      FIG. 6  represents an alternative overview block diagram of the SMU  202 . The SMU  202  is scalable and capable of having multiple power sources as inputs and multiple power sources as output. The SMU  202  can be used for a plurality (“n”) of AC and/or DC input sources and can provide output as any number (“n”) of AC and/or DC outputs including multiple battery charging capabilities of different battery types. A plurality of AC inputs including AC input terminal  1   202   g,  AC input terminal  2   202   h  through AC input “n”  202   i  provide power from AC mains  204  and other sources to SMU  202 . In addition to the battery input,  202   a,  controlled switching element  202   f  also has DC source terminal  1  ( 202   b ) and DC source terminal  2  ( 202   q ) which can provide DC power from alternative power sources such as additional solar panels, wind or diesel. Controlled switching element  202   f  also has DC source terminal  1  ( 202   p ) and DC source terminal  2  ( 202   q ) which can provide DC power from alternative power sources such as additional solar panels, wind or diesel. SMU  202  can also take additional sources of AC power or DC power as input and a control mechanism is provided to switch the input AC mains to other alternative AC sources. In addition, battery  214  charging can be done from the incoming power from other DC power sources and an appropriate control mechanism is provided. 
         [0037]      FIG. 7  illustrates a method  700  of operating a solar power system with the SMU  202  in it. In a first step, the SMU  202  is connected along with a solar panel  226  into an existing inverter based backup power supply system or UPS system. Optionally, a mode of operation (either urban or rural) is selected  704  depending on the designated environment of the solar power system. The next step is to initialize  706  the system by identifying the battery  214  capacity, inverter  210  capacity and solar panel  226  power capacity. The SMU  202  will next start to collect measurements on the load pattern from the load  220  and will do so on a continuous basis (step  708 ). In step  710 , the SMU  202  receives information on operating conditions of the system including, but not limited to, temperature on the panel, whether the panel is receiving less than ideal sunshine due to clouds or darkness, whether the AC mains power is available, and/or whether the battery needs to be charged. In step  712 , the SMU  202  will determine whether to charge the battery from the solar panel  226 , from AC mains  204  or from both. In step  714  the SMU  202  will decide based on the system operating conditions of the system and the priority sequence programmed into the microcontroller  202   x  whether to provide power to the load  220  from AC mains  204 , the battery  214  or the solar panel  226 . 
         [0038]    Devices that are described as in “communication” with each other or “coupled” to each other need not be in continuous communication with each other or in direct physical contact, unless expressly specified otherwise. On the contrary, such devices need only transmit to each other as necessary or desirable, and may actually refrain from exchanging data most of the time. For example, devices that are in communication with or coupled with each other may communicate directly or indirectly through one or more intermediaries. 
         [0039]    Although process (or method) steps may be described or claimed in a particular sequential order, such processes may be configured to work in different orders. In other words, any sequence or order of steps that may be explicitly described or claimed does not necessarily indicate a requirement that the steps be performed in that order unless specifically indicated. Further, some steps may be performed simultaneously despite being described or implied as occurring non-simultaneously (e.g., because one step is described after the other step) unless specifically indicated. Moreover, the illustration of a process by its depiction in a drawing does not imply that the illustrated process is exclusive of other variations and modifications thereto, does not imply that the illustrated process or any of its steps are necessary to the embodiment(s), and does not imply that the illustrated process is preferred. 
         [0040]    Although illustrative embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments. As such, many modifications and variations will be apparent to practitioners skilled in this art. Accordingly, it is intended that the scope of the invention be defined by the following claims and their equivalents. Furthermore, it is contemplated that a particular feature described either individually or as part of an embodiment can be combined with other individually described features, or parts of other embodiments, even if the other features and embodiments make no mentioned of the particular feature. This, the absence of describing combinations should not preclude the inventor from claiming rights to such combinations.