Patent Application
20130207473
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.
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
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.
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.
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.
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).
One of the issues when using solar power as a source is the temperature levels at the solar panels. A solar panel'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 Voc, or open circuit voltage, reduces significantly and Isc, 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 Voc drops, and the panel works at new maximum power point voltage (VMPP) and maximum power point current (IMPP) 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.
For example, in a first embodiment shown in
In the solar power source system of
The battery terminals 202a of the SMU 202 may be connected via DC line 212 to the battery terminals 214a 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 202c 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).
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 202x) or any combination thereof. A decision tree for prioritization of energy storage as well as energy use can be programmed into a microcontroller 202x 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:
a. Solar→Battery→Grid
b. Solar→Grid→Battery
c. Grid→Solar→Battery
d. Grid→Battery→Solar
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) 202d 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) 202d the environment mode may be changed through the monitoring system 224 which allows the mode to be controlled remotely.
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 202x of the SMU 202, the battery 214 may also be charged from AC mains 204 using a mains charger 210b located in the inverter 210 through line 216. When battery charge level reaches a predetermined or preprogrammed level in a microcontroller 202x, 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 202x, 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.).
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.
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 202x 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 202x. AC mains 204 will start charging the battery 214 when the battery voltage will drop below a minimum battery charge level referred as Vbmin 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 Vbmin and Vbmax 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 202x 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.
In another system setup as illustrated in
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.
The microcontroller 202x is further programmed to direct priority logic and switching elements 202f through communication line 2021. The priority logic and switching elements module 202f is configured to provide the battery charge 202h from solar panel 226 through terminal 202a to charge the battery 214. In the case of
Details of the plurality of internal connections and method of operation of the SMU 202 are disclosed in
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.
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.
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.
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.
| Number | Date | Country | |
|---|---|---|---|
| 61595075 | Feb 2012 | US |
