CA2728619A1 - A renewable power control system - Google Patents
A renewable power control system Download PDFInfo
- Publication number
- CA2728619A1 CA2728619A1 CA 2728619 CA2728619A CA2728619A1 CA 2728619 A1 CA2728619 A1 CA 2728619A1 CA 2728619 CA2728619 CA 2728619 CA 2728619 A CA2728619 A CA 2728619A CA 2728619 A1 CA2728619 A1 CA 2728619A1
- Authority
- CA
- Canada
- Prior art keywords
- combiner
- control system
- renewable power
- power control
- controller
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000012423 maintenance Methods 0.000 description 3
- 230000005611 electricity Effects 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/02016—Circuit arrangements of general character for the devices
- H01L31/02019—Circuit arrangements of general character for the devices for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/02021—Circuit arrangements of general character for the devices for devices characterised by at least one potential jump barrier or surface barrier for solar cells
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
- H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B10/00—Integration of renewable energy sources in buildings
- Y02B10/10—Photovoltaic [PV]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Control Of Electrical Variables (AREA)
Abstract
A renewable power control system is disclosed. The system includes a control unit and a combiner, wherein the control unit measures the output of each power source connected to the combiner and forwards the 'combination' settings to the combiner. The combiner connects the power source in series and/or parallel depending on the settings received from the control unit. The control unit ensures the maximum power point is maintained at all times.
Description
Field of Invention This invention relates to energy conversion and more particularly to methods and apparatus for controlling power drawn from an energy combiner operable to convert energy from a physical source into electrical energy.
Background of the Invention Solar power is a clean and renewable source of energy that has mass market appeal.
Among its many uses, solar power can be used to convert the energy from the sun either directly or indirectly into electricity. The photovoltaic cell is a device for converting sunlight energy directly into electricity. When photovoltaic cells are used in this manner they are typically referred to as solar cells. A solar cell array or module is simply a group of solar cells electrically connected and packaged together.
Energy conversion devices such as photovoltaic arrays are commonly used to provide power to electrical loads. Often these loads are direct current (DC) loads such as batteries, for example. Recently, efficiencies in power conversion devices are giving rise to solar power systems that supply power to an alternating current (AC) load such as an AC power grid such as may be operated by a public utility company. Such power systems may employ a photovoltaic array and an interface for converting power in a form received from the photovoltaic array into a form operable to be received by the AC power grid. Such an interface may involve a DC to AC inverter.
Interfaces of the type described above often seek to cause maximum power to be provided to the AC power grid. The maximum power available to be provided to the AC
power grid depends upon the conditions under which the energy conversion device is operated and in the case of a photovoltaic array, these conditions include the amount of insolation and the temperature of the array, for example. A maximum power point, or voltage at which maximum power may be extracted from the array, is a desirable point at which to operate the array and conventional systems seek to find this point.
The maximum power point changes however, due to changes in insolation and due to changes in temperature of the array and thus control systems are employed to constantly seek this point.
One way of seeking the maximum power point is to periodically perturb and observe the power output of the solar cells and then adjust the combiner accordingly to cause the voltage of the solar cells to be as close as possible to the maximum power point.
Summary of the Invention Therefore, a main object of the present invention is to enable interconnection of a plurality of solar cell strings having different output voltages to a converter/inverter power supply in a simple manner, and to enable efficient use of the maximum output power of the solar cell strings.
Briefly stated, the present invention relates to a solar generation system in which a DC
voltage output from a solar cell is inter-connected, automatically, within the combiner, to ensure stable DC voltage is supplied to an converter/inverter apparatus converting the solar cell output voltage to either higher DC voltage or to AC voltage.
For example, when the solar cell strings are to be placed on the roof of a house, sometimes it is difficult to configure solar cell strings by arranging solar cell modules only that surface of the roof which faces the sun and receiving the most of the sunshine.
Solar cell modules that are positioned not on the sunny surface of the roof may be arranged on the eastward or westward surface of the roof to form the solar cell strings.
Sometimes, the solar cell strings are configured by placing small size solar cell modules arranged in the remaining peripheral regions after the solar cell modules are placed on the main portion of the sunny surface of the roof. More specifically, sometimes the number of series-connected solar cell modules included in some solar cell strings is different from other solar cell strings. In such a case, different output voltages result from different solar cell strings.
Unless the power from different solar cell string can be fed efficiently to power conditioner, the area occupied by the substandard solar cell string would be wasted.
The combiner takes power from different solar cells, and connects them in a pattern which is controlled by the controller, to maximize the DC voltage output.
The combiner, on command from the controller, by-passes (disconnects) damaged solar cells and the maintenance crew is notified to schedule an inspection.
Therefore, according to the present invention, as the DC voltage from the substandard solar cell string is increased to the DC voltage of the standard solar cell string, interconnection to the utility power supply is possible in a simple manner, and the sum of the maximum outputs from respective solar cell strings can be used as the final maximum output power.
To implement the anti-islanding requirement, the input connecting circuit includes a trip signal generating circuit generating a trip signal when the output voltage attains to an over voltage, and a breaker opening the connection between the solar cells input connecting circuit in response to the trip signal from the trip signal generating circuit.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
Brief Description of the Drawings In drawings which illustrate by way of example only a preferred embodiment of the present invention, Figure 1 is a block diagram of one embodiment of the present invention;
Figure 2 is a graphical representation of one of the setting of the combiner;
and Figure 3 is a graphical representation of one of the alternate setting of the combiner showing a disconnected solar cell.
Detailed Description of the Invention As shown in Figure 1, in one embodiment the present invention comprises a Controller (12) connected to combiner (14) via a control bus (22). The solar lo cells (16) are connected to combiner (14) and also to controller (12) via sensor (20). Controller (12) monitors the output voltage of solar cells (16) and also the output (18) of combiner (14) via sensor (20) Upon power-up or reset, the Controller (12) sends the `reset' command to combiner (14) via the control bus (22) which opens all connections within combiner (14) to ensure the start-up output voltage (18) from combiner (14) is zero which is monitored by controller (12) to ensure the combiner (14) acted on the command.
2o After the reset command is sent to the combiner (14), the controller (12) monitors the output voltage of solar cells (16) via sensor (20) and calculates the setting for combiner (14). The new calculated setting is sent to combiner (14) via control bus (22) and the output (18) of combiner (14) is monitored by controller (12) via sensor 20, thus the setting of combiner (14) can be optimized by controller (12) on a regular bases.
As shown in Figure 2, some of the solar cells are connected in series to get maximum voltage from the string while rest of the solar cells are connected in parallel.
As shown in figure 3, a solar cell (16) can be bypassed by the controller (12) either due to maintenance command received via the network (24) or if the output voltage of the solar cell (16) is out of specification. In the example shown (figure 3), the solar cell (16) connected to input 2 of combiner (14) is bypassed due to update in settings from the controller (12).
When the output voltage of solar cell (16) is out of specification, controller (12) informs the local control station (26) and/or a remote control station (28) of the problem, thus creating a maintenance request which can scheduled without affecting the operation of the system.
Network (24) can be wired or wireless depending on the local conditions.
It should be noted that within combiner (14), `break-before-make' concept is used to prevent short-circuits or over-voltage condition at output (18), thus the combiner (14) is reset before new settings are sent via the control bus (22), to combiner (14), by controller (12).
Controller (12) can be programmed either locally or remotely using the network (24). Also, the sensor (20) readings can be monitored via the network (24) A preferred embodiment of the invention having thus been described by way of example only, it will be apparent to those skilled in the art that modifications and adaptations may be made without departing from the scope of invention, as set out in the appended claims.
Background of the Invention Solar power is a clean and renewable source of energy that has mass market appeal.
Among its many uses, solar power can be used to convert the energy from the sun either directly or indirectly into electricity. The photovoltaic cell is a device for converting sunlight energy directly into electricity. When photovoltaic cells are used in this manner they are typically referred to as solar cells. A solar cell array or module is simply a group of solar cells electrically connected and packaged together.
Energy conversion devices such as photovoltaic arrays are commonly used to provide power to electrical loads. Often these loads are direct current (DC) loads such as batteries, for example. Recently, efficiencies in power conversion devices are giving rise to solar power systems that supply power to an alternating current (AC) load such as an AC power grid such as may be operated by a public utility company. Such power systems may employ a photovoltaic array and an interface for converting power in a form received from the photovoltaic array into a form operable to be received by the AC power grid. Such an interface may involve a DC to AC inverter.
Interfaces of the type described above often seek to cause maximum power to be provided to the AC power grid. The maximum power available to be provided to the AC
power grid depends upon the conditions under which the energy conversion device is operated and in the case of a photovoltaic array, these conditions include the amount of insolation and the temperature of the array, for example. A maximum power point, or voltage at which maximum power may be extracted from the array, is a desirable point at which to operate the array and conventional systems seek to find this point.
The maximum power point changes however, due to changes in insolation and due to changes in temperature of the array and thus control systems are employed to constantly seek this point.
One way of seeking the maximum power point is to periodically perturb and observe the power output of the solar cells and then adjust the combiner accordingly to cause the voltage of the solar cells to be as close as possible to the maximum power point.
Summary of the Invention Therefore, a main object of the present invention is to enable interconnection of a plurality of solar cell strings having different output voltages to a converter/inverter power supply in a simple manner, and to enable efficient use of the maximum output power of the solar cell strings.
Briefly stated, the present invention relates to a solar generation system in which a DC
voltage output from a solar cell is inter-connected, automatically, within the combiner, to ensure stable DC voltage is supplied to an converter/inverter apparatus converting the solar cell output voltage to either higher DC voltage or to AC voltage.
For example, when the solar cell strings are to be placed on the roof of a house, sometimes it is difficult to configure solar cell strings by arranging solar cell modules only that surface of the roof which faces the sun and receiving the most of the sunshine.
Solar cell modules that are positioned not on the sunny surface of the roof may be arranged on the eastward or westward surface of the roof to form the solar cell strings.
Sometimes, the solar cell strings are configured by placing small size solar cell modules arranged in the remaining peripheral regions after the solar cell modules are placed on the main portion of the sunny surface of the roof. More specifically, sometimes the number of series-connected solar cell modules included in some solar cell strings is different from other solar cell strings. In such a case, different output voltages result from different solar cell strings.
Unless the power from different solar cell string can be fed efficiently to power conditioner, the area occupied by the substandard solar cell string would be wasted.
The combiner takes power from different solar cells, and connects them in a pattern which is controlled by the controller, to maximize the DC voltage output.
The combiner, on command from the controller, by-passes (disconnects) damaged solar cells and the maintenance crew is notified to schedule an inspection.
Therefore, according to the present invention, as the DC voltage from the substandard solar cell string is increased to the DC voltage of the standard solar cell string, interconnection to the utility power supply is possible in a simple manner, and the sum of the maximum outputs from respective solar cell strings can be used as the final maximum output power.
To implement the anti-islanding requirement, the input connecting circuit includes a trip signal generating circuit generating a trip signal when the output voltage attains to an over voltage, and a breaker opening the connection between the solar cells input connecting circuit in response to the trip signal from the trip signal generating circuit.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
Brief Description of the Drawings In drawings which illustrate by way of example only a preferred embodiment of the present invention, Figure 1 is a block diagram of one embodiment of the present invention;
Figure 2 is a graphical representation of one of the setting of the combiner;
and Figure 3 is a graphical representation of one of the alternate setting of the combiner showing a disconnected solar cell.
Detailed Description of the Invention As shown in Figure 1, in one embodiment the present invention comprises a Controller (12) connected to combiner (14) via a control bus (22). The solar lo cells (16) are connected to combiner (14) and also to controller (12) via sensor (20). Controller (12) monitors the output voltage of solar cells (16) and also the output (18) of combiner (14) via sensor (20) Upon power-up or reset, the Controller (12) sends the `reset' command to combiner (14) via the control bus (22) which opens all connections within combiner (14) to ensure the start-up output voltage (18) from combiner (14) is zero which is monitored by controller (12) to ensure the combiner (14) acted on the command.
2o After the reset command is sent to the combiner (14), the controller (12) monitors the output voltage of solar cells (16) via sensor (20) and calculates the setting for combiner (14). The new calculated setting is sent to combiner (14) via control bus (22) and the output (18) of combiner (14) is monitored by controller (12) via sensor 20, thus the setting of combiner (14) can be optimized by controller (12) on a regular bases.
As shown in Figure 2, some of the solar cells are connected in series to get maximum voltage from the string while rest of the solar cells are connected in parallel.
As shown in figure 3, a solar cell (16) can be bypassed by the controller (12) either due to maintenance command received via the network (24) or if the output voltage of the solar cell (16) is out of specification. In the example shown (figure 3), the solar cell (16) connected to input 2 of combiner (14) is bypassed due to update in settings from the controller (12).
When the output voltage of solar cell (16) is out of specification, controller (12) informs the local control station (26) and/or a remote control station (28) of the problem, thus creating a maintenance request which can scheduled without affecting the operation of the system.
Network (24) can be wired or wireless depending on the local conditions.
It should be noted that within combiner (14), `break-before-make' concept is used to prevent short-circuits or over-voltage condition at output (18), thus the combiner (14) is reset before new settings are sent via the control bus (22), to combiner (14), by controller (12).
Controller (12) can be programmed either locally or remotely using the network (24). Also, the sensor (20) readings can be monitored via the network (24) A preferred embodiment of the invention having thus been described by way of example only, it will be apparent to those skilled in the art that modifications and adaptations may be made without departing from the scope of invention, as set out in the appended claims.
Claims (9)
1. A renewable power control system, comprising: a control unit having an input, an output and a control terminal for tracking and controlling the system; a combiner for connecting unstable low voltage DC power sources into maximum voltage DC
power.
power.
2. The renewable power control system as claimed in claim 1, wherein the combiner is connected to a renewable power source to receive the low voltage DC power.
3. The renewable power control system as claimed in claim 2, wherein the renewable power source is a solar panel.
4. The renewable power control system as claimed in claim 2 wherein said power source comprises one or more solar panel.
5. The renewable power control system as claimed in claim 2 wherein the controller sets the combiner to connect the solar panel in parallel or serial string.
6. The renewable power control system as claimed in claim 5, wherein the combiner is connected to the DC bus and controlled by the control unit.
7. The renewable power control system as claimed in claim 1, wherein the controller is networked to local control station.
8. The renewable power control system as claimed in claim 1, wherein the controller is networked to remote control station.
9. The renewable power control system as claimed in claim 1, wherein the controller is programmable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2728619 CA2728619A1 (en) | 2011-01-18 | 2011-01-18 | A renewable power control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2728619 CA2728619A1 (en) | 2011-01-18 | 2011-01-18 | A renewable power control system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2728619A1 true CA2728619A1 (en) | 2012-07-18 |
Family
ID=46514918
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2728619 Abandoned CA2728619A1 (en) | 2011-01-18 | 2011-01-18 | A renewable power control system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2728619A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103137730A (en) * | 2013-02-01 | 2013-06-05 | 常州亿晶光电科技有限公司 | Method and structure for avoiding or reducing crystalline silicon photovoltaic assembly potential induction damping |
| EP3070570A4 (en) * | 2013-11-14 | 2017-08-09 | Sion Electric Co., Ltd | Power source device |
-
2011
- 2011-01-18 CA CA 2728619 patent/CA2728619A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103137730A (en) * | 2013-02-01 | 2013-06-05 | 常州亿晶光电科技有限公司 | Method and structure for avoiding or reducing crystalline silicon photovoltaic assembly potential induction damping |
| CN103137730B (en) * | 2013-02-01 | 2015-05-20 | 常州亿晶光电科技有限公司 | Method and structure for avoiding or reducing crystalline silicon photovoltaic assembly potential induction damping |
| EP3070570A4 (en) * | 2013-11-14 | 2017-08-09 | Sion Electric Co., Ltd | Power source device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |
Effective date: 20140120 |