CN210806749U - Grid-connected and grid-disconnected switching circuit for energy storage system - Google Patents
Grid-connected and grid-disconnected switching circuit for energy storage system Download PDFInfo
- Publication number
- CN210806749U CN210806749U CN201922151077.XU CN201922151077U CN210806749U CN 210806749 U CN210806749 U CN 210806749U CN 201922151077 U CN201922151077 U CN 201922151077U CN 210806749 U CN210806749 U CN 210806749U
- Authority
- CN
- China
- Prior art keywords
- grid
- circuit
- inverter
- switch
- power
- 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.)
- Active
Links
Images
Landscapes
- Inverter Devices (AREA)
Abstract
A grid-connected and off-grid switching circuit for an energy storage system comprises a first switch circuit connected between a power output end of an inverter and a power output end of a power grid, a second switch circuit connected between a power grounding end of the inverter and the power grounding end of the power grid, a third switch circuit connected between the power output end of the inverter and the power grounding end of the power grid and connected with an energy consumption load, and further comprises a first switch control circuit and a first voltage monitoring circuit. The first switch control circuit controls the disconnection or connection of the first switch circuit, the second switch circuit and the third switch circuit according to the voltage result output by the monitoring inverter of the first voltage monitoring circuit, so that the inverter is omitted from a network circuit, the on/off mode of the inverter is shared by one output port, the size of the inverter is reduced, a double-power switch is omitted, the production cost of the energy storage system is reduced, the independent control and off-network switching can be realized, the communication with the inverter is not needed, and the independent external use is realized.
Description
Technical Field
The application belongs to the technical field of power electronic equipment, and particularly relates to a grid-connected and off-grid switching circuit for an energy storage system.
Background
With the development of distributed power generation technology, a conventional centralized power generation system is being transformed to a distributed power generation system. The distributed power generation system is close to the load, the power supply reliability is high, power can be supplied to remote mountainous areas or commercial areas, and the power transmission loss is reduced. The energy problem of China is effectively relieved, and the power supply reliability is improved. The distributed power generation system mainly comprises a distributed power supply, an energy storage device, a load and a power grid, and the energy storage inverter has the function of peak clipping and valley filling, so that the distributed power generation system is widely applied to the distributed power generation system, but distributed systems such as photovoltaic power generation and wind power generation have the characteristics of randomness and intermittence, so that an energy storage link needs to be added to the system in order to maintain stable frequency, balanced power and stable voltage when the distributed power generation system operates in an isolated island mode. The grid connection/grid disconnection switching dynamic process of the energy storage power supply directly affects the power supply quality of the sensitive load, so that the grid connection/grid disconnection switching circuit for the energy storage inverter is particularly important.
At present, an extra set of relay, control circuit and sampling circuit is needed when the grid-connected and grid-disconnected integrated inverter outputs the grid-disconnected. The off-grid output circuit is controlled and detected by the inverter control chip and cannot be externally arranged, so that the size of the inverter is increased. The inverter also needs an external dual-power transfer switch, the dual-power switch is expensive, and a special wiring and a junction box are needed, so that the system cost is increased.
Disclosure of Invention
In order to solve the shortcoming and the deficiency that exist among the prior art, the utility model provides a and from net switching circuit realizes energy storage system's the state of being incorporated into the power networks or leaving the net and switch.
According to a first aspect, an embodiment provides a grid-connected and grid-disconnected switching circuit for an energy storage system, where the grid-connected and grid-disconnected switching circuit is used to be connected among an inverter, a power grid and a load device of the energy storage system, so as to control the energy storage system to switch a grid-connected or grid-disconnected state, and further output an ac power output by the inverter to the power grid or the load device;
the grid-connected and off-grid switching circuit comprises a first inverter connecting end, a second inverter connecting end, a first load connecting end, a second load connecting end, a first power grid connecting end and a second power grid connecting end; the first inverter connecting end and the second inverter connecting end are respectively connected with the power output end and the power grounding end of the inverter; the first load connecting end and the second load connecting end are used for being connected with an input power supply end and an input power supply grounding end of the load device respectively; the first power grid connection end and the second power grid connection end are used for being connected with a power grid power supply output end and a power grid power supply grounding end of the power grid respectively; the first inverter connection end is connected with the first load connection end;
the grid-connected and off-grid switching circuit further comprises a first switch control circuit, a first voltage monitoring circuit, a first switch circuit, a second switch circuit, a third switch circuit and an energy consumption load; the first switching circuit is connected to the first inverter connection end and the first grid connection end; the second switching circuit is connected to the second inverter connecting end and the second power grid connecting end; the third switch circuit and the energy consumption load are connected in series to the first inverter connecting end and the second inverter connecting end; the first voltage monitoring circuit is used for monitoring the voltage between the first inverter connecting end and the second inverter connecting end and sending a first electric signal to the first switch control circuit when the voltage is monitored;
the first switch control circuit is respectively connected with the first switch circuit, the second switch circuit and the third switch circuit and used for responding to the first electric signal and respectively sending a first switch control electric signal, a second switch control electric signal and a third switch control electric signal to the first switch circuit, the second switch circuit and the third switch circuit, and the first switch circuit, the second switch circuit and the third switch circuit are respectively used for responding to the first switch control electric signal, the second switch control electric signal and the third switch control electric signal to be switched on or switched off.
Further, still include second voltage monitoring circuit for monitor the voltage between first electric wire netting link and the second electric wire netting link, and when the voltage of monitoring is greater than a preset voltage to first switch control circuit sends the second signal of telecommunication, first switch control circuit still is used for responding the second signal of telecommunication respectively to first switch circuit and second switch circuit send fourth switch control signal of telecommunication and fifth switch control signal of telecommunication, first switch circuit and second switch circuit are used for responding respectively fourth switch control signal of telecommunication and fifth switch control signal of telecommunication switch on or break off.
And the auxiliary power supply circuit is used for providing power supply for the grid-connected and off-grid switching circuit.
Further, the load protection circuit further comprises an overload protector which is connected between the first inverter connecting end and the first load connecting end in series and used for providing overcurrent protection.
Further, the first, second, and/or third switching circuits include relays.
According to a second aspect, an embodiment provides a grid-connected and off-grid switching circuit for an energy storage system, the grid-connected and off-grid switching circuit is used for being connected among an inverter, a power grid and a load device of the energy storage system, and controlling the energy storage system to switch a grid-connected state or an off-grid state so as to output a three-phase alternating current power supply output by the inverter to the power grid or the load device;
the grid-connected and off-grid switching circuit comprises a third inverter connecting end, a fourth inverter connecting end, a fifth inverter connecting end, a sixth inverter connecting end, a third load connecting end, a fourth load connecting end, a fifth power grid connecting end, a sixth load connecting end, a third power grid connecting end, a fourth power grid connecting end, a fifth power grid connecting end and a sixth power grid connecting end;
the third inverter connecting end, the fourth inverter connecting end, the fifth inverter connecting end and the sixth inverter connecting end are respectively connected with the A-phase power output end, the B-phase power output end, the C-phase power output end and the power ground end of the inverter;
the third load connecting end, the fourth load connecting end, the fifth power grid connecting end and the sixth load connecting end are respectively connected with an input phase A power source end, an input phase B power source end, an input phase C power source end and an input power source grounding end of the load device;
the third power grid connecting end, the fourth power grid connecting end, the fifth power grid connecting end and the sixth power grid connecting end are respectively connected with a power grid A-phase power output end, a power grid B-phase power output end, a power grid C-phase power output end and a power grid grounding end of the power grid;
the grid-connected and off-grid switching circuit comprises a first switch control circuit, a first voltage monitoring circuit, a fourth switch circuit, a fifth switch circuit, a sixth switch circuit, a seventh switch circuit, a third switch circuit and an energy consumption load;
the fourth switching circuit is connected to the third inverter connection end and the third grid connection end, the fifth switching circuit is connected to the fourth inverter connection end and the fourth grid connection end, the sixth switching circuit is connected to the fifth inverter connection end and the fifth grid connection end, and the seventh switching circuit is connected to the fifth inverter connection end and the fifth grid connection end; the third switch circuit is connected with the energy consumption load in series and is connected between the connection end of the third inverter and the connection end of the sixth inverter in series, or is connected between the connection end of the fourth inverter and the connection end of the sixth inverter in series, or is connected between the connection end of the fifth inverter and the connection end of the sixth inverter in series;
the first voltage monitoring circuit is used for monitoring the voltage of the power output end of the inverter and sending a third electric signal to the first switch control circuit when the voltage is monitored; the first switch control circuit is respectively connected with the fourth switch circuit, the fifth switch circuit, the sixth switch circuit, the seventh switch circuit and the third switch circuit, and is used for responding to the third electric signal to respectively send a fourth switch control electric signal, a fifth switch control electric signal, a sixth switch control electric signal, a seventh switch control electric signal and an eighth switch control electric signal to the fourth switch circuit, the fifth switch circuit, the sixth switch control electric signal, the seventh switch control electric signal and the eighth switch control electric signal, and the fourth switch circuit, the fifth switch circuit, the sixth switch circuit, the seventh switch circuit and the third switch circuit are respectively used for responding to the fourth switch control electric signal, the fifth switch control electric signal, the sixth switch control electric signal, the seventh switch control electric signal and the eighth switch control electric signal to be turned on or turned off.
The first switch control circuit is used for controlling the first switch control circuit to switch on and off according to the first electric signal; the first switch control circuit is further configured to send a ninth switch control electrical signal, a tenth switch control electrical signal, an eleventh switch control electrical signal and a twelfth switch control electrical signal to the fourth switch circuit, the fifth switch circuit, the sixth switch circuit and the seventh switch circuit respectively in response to the fourth electrical signal, and the fourth switch circuit, the fifth switch circuit, the sixth switch circuit and the seventh switch circuit are configured to be turned on or off in response to the ninth switch control electrical signal, the tenth switch control electrical signal, the eleventh switch control electrical signal and the twelfth switch control electrical signal respectively.
And the auxiliary power supply circuit is used for providing power supply for the grid-connected and off-grid switching circuit.
And the three overload protectors are respectively connected between the third inverter connecting end and the third load connecting end, between the fourth inverter connecting end and the fourth load connecting end and between the fifth inverter connecting end and the fifth load connecting end in series and used for providing overcurrent protection.
Further, the fourth, fifth, sixth, seventh and/or third switching circuits comprise relays.
According to the embodiment, the grid-connected and off-grid switching circuit for the energy storage system comprises a first switch control circuit, a first voltage monitoring circuit, a first switch circuit, a second switch circuit, a third switch circuit and an energy consumption load. The first switch circuit is connected between the power output end of the inverter and the power output end of the power grid, the second switch circuit is connected between the power ground end of the inverter and the power ground end of the power grid, the third switch circuit and the energy-consuming load are connected between the power output end of the inverter and the power ground end of the power grid, the first voltage monitoring circuit is used for monitoring the voltage output by the inverter, the first switch control circuit controls the disconnection or the connection of the first switch circuit, the second switch circuit and the third switch circuit according to the monitoring result of the first voltage monitoring circuit, because the off-grid circuit of the inverter is omitted, the grid-connected mode and the off-grid mode of the inverter share one output port, the size of the inverter is reduced, the off-grid circuit and the double power supplies of the inverter are omitted, the production cost of the energy storage system is reduced, and the on-grid switching can, realize the external use alone.
Drawings
FIG. 1 is a circuit diagram of a grid-connected and off-grid switching circuit;
FIG. 2 is a schematic circuit diagram of an embodiment of a grid-connected and off-grid switching circuit;
fig. 3 is a schematic circuit diagram of a parallel-to-grid and off-grid switching circuit according to another embodiment.
Detailed Description
The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.
Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.
The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).
Referring to fig. 1, a circuit diagram of an on-grid and off-grid switching circuit is shown, the switching circuit is connected among an inverter, a grid and a load device of an energy storage system, and the switching circuit includes a first output port L1 and a second output port N1 for connecting with the inverter, a first wiring port L2 and a second wiring port N2 for connecting with a live wire and a neutral wire of the grid, and a first power supply port L3 and a second power supply port N3 for connecting with the load device. Further included are a first relay S1, a second relay S2, a third relay S3, a fourth relay S4, a fifth relay S5, a sixth relay S6, a seventh relay S7, and an eighth relay S8, wherein the first relay S1 and the second relay S2 are connected in series between the first output port L1 and the first wiring port L2, the third relay S3 and the fourth relay S4 are connected in series between the second output port N1 and the second wiring port N2, the fifth relay S5 and the sixth relay S6 are connected in series between the first output port L1 and the first power supply port L3, and the seventh relay S7 and the eighth relay S8 are connected in series between the second output port N1 and the second power supply port N3. The first output port L1 and the second output port N1 are used as a grid-connected output port or an off-grid output port, respectively, and are used for replacing a power supply for supplying power to a load in a normal or abnormal state of a power grid. The switching circuit further comprises an on-off circuit D which comprises a relay or a contactor respectively connected between the first wiring port L2 and the first power supply port L3, and between the second power supply port N3 and the second wiring port N2, and is used for being connected with a voltage monitoring circuit to monitor the power supply state of the power grid. In the switching circuit, each relay is connected with the relay control circuit, and in order to prevent the short circuit of the whole switching circuit caused by the fault of a single relay, the double-switch relays are adopted to be connected in series, but the mode only reduces the probability of the short circuit and cannot completely prevent the short circuit accident.
In the embodiment of the invention, the switch circuit and the energy consumption load are connected in series between the power output end and the power grounding end of the inverter, so that when the inverter enters the off-grid working mode in advance, the switch circuit is controlled to connect the energy consumption load in series between the power output end and the power grounding end of the inverter, the energy consumption load is periodically switched at the preset frequency, and the off-grid is closed when the inverter detects that the output load periodically fluctuates according to the preset frequency.
Example one
Referring to fig. 2, a schematic diagram of a circuit structure of a grid-connected and grid-disconnected switching circuit according to an embodiment is shown, and the grid-connected and grid-disconnected switching circuit 4 is used to be connected between an inverter 1, a grid 2 and a load device 3 of an energy storage system, so as to control the energy storage system to switch a grid-connected or grid-disconnected state, and further output an ac power output by the inverter 1 to the grid 2 or the load device 3. And off-grid switching circuit 4 includes first dc-to-ac converter link, second dc-to-ac converter link, first load link, second load link, first electric wire netting link and second electric wire netting link. The first inverter connecting end and the second inverter connecting end are respectively used for being connected with a power output end and a power grounding end of the inverter 1, and the first load connecting end and the second load connecting end are respectively used for being connected with an input power end and an input power grounding end of the load device 3. The first power grid connecting end and the second power grid connecting end are respectively used for being connected with a power grid power supply output end and a power grid power supply grounding end of the power grid 2, and the first inverter connecting end is connected with the first load connecting end. The grid-connected/off-grid switching circuit 4 includes a first switch control circuit 40, a first voltage monitoring circuit 44, a first switch circuit 41, a second switch circuit 42, a third switch circuit 43A, and an energy consuming load 43B. The first switch circuit 41 is connected between the first inverter connection terminal and the first grid connection terminal, the second switch circuit 42 is connected between the second inverter connection terminal and the second grid connection terminal, the third switch circuit 43A and the energy consumption load 43B are connected in series between the first inverter connection terminal and the second inverter connection terminal, and the first voltage monitoring circuit 44 is configured to monitor a voltage between the first inverter connection terminal and the second inverter connection terminal, and send a first electrical signal to the first switch control circuit 40 when the voltage is monitored. The first switch control circuit 40 is connected to the first switch circuit 41, the second switch circuit 42, and the third switch circuit 43A, respectively, and is configured to transmit a first switch control electrical signal, a second switch control electrical signal, and a third switch control electrical signal to the first switch circuit 41, the second switch circuit 42, and the third switch circuit 43A, respectively, in response to a first electrical signal, and the first switch circuit 41, the second switch circuit 42, and the third switch circuit 43A are configured to be turned on or off in response to the first switch control electrical signal, the second switch control electrical signal, and the third switch control electrical signal, respectively. In an embodiment, the grid-connected/off-grid switching circuit 4 further includes a second voltage monitoring circuit, configured to monitor a voltage between the first grid connection terminal and the second grid connection terminal, and send a second electrical signal to the first switch control circuit 40 when the monitored voltage is greater than a preset voltage, the first switch control circuit 40 is further configured to send a fourth switch control electrical signal, a fifth switch control electrical signal, and a sixth switch control electrical signal to the first switch circuit 41, the second switch circuit 42, and the third switch circuit 43A respectively in response to the second electrical signal, and the first switch circuit 41, the second switch circuit 42, and the third switch circuit 43A are configured to be turned on or off in response to the fourth switch control electrical signal, the fifth switch control electrical signal, and the sixth switch control electrical signal respectively. In one embodiment, the grid-connected and off-grid switching circuit 2 further includes an auxiliary power circuit 46 for providing power to the grid-connected and off-grid switching circuit. In an embodiment, the auxiliary power circuit 46 is connected to the grid 2 for obtaining power from the grid 2. In one embodiment, the grid-to-grid switching circuit 2 further comprises an overload protector 47 connected in series between the first inverter connection terminal and the first load connection terminal for providing overcurrent protection. In one embodiment, the overload protector 47 includes a fuse. In one embodiment, the grid-connected and off-grid switching circuit 2 includes a relay in the first switch circuit 41, the second switch circuit 42, and/or the third switch circuit 43A. In an embodiment, the energy consuming load 43B includes a first resistor, the first resistor is connected in series with the third switch circuit 43A and then connected between the first inverter connection terminal and the second inverter connection terminal, when the power grid 2 is powered off and the inverter 1 is in an off-grid output state, if the power grid recovers power supply, a voltage monitored by the first voltage monitoring circuit changes, the first switch control circuit 40 sends a first electric signal to the first switch control circuit 40, the first switch control circuit 40 obtains the first electric signal and confirms that the inverter 1 is in the off-grid state, the first switch control circuit 40 sends a third switch control electric signal to the third switch circuit 43A, the third switch circuit 43A responds to the third switch control electric signal to conduct, and performs preset frequency periodic switching on the first resistor, and the inverter 1 detects that the off-grid load meets the preset frequency periodic change, and disconnects the off-grid output. The voltage monitored by the first voltage monitoring circuit changes again and then sends a first electric signal to the first switch control circuit 40, after the first switch control circuit 40 acquires the first electric signal again and confirms that the inverter is closed and outputs off the grid, the third switch control electric signal is sent to the third switch circuit 43A again, the third switch circuit 43A responds to the third switch control electric signal again to be disconnected, and the first resistor does not consume energy any more. The first switch control circuit 40 sends a first switch control electric signal and a second switch control electric signal to the first switch circuit 41 and the second switch circuit 42, the first switch circuit 41 and the second switch circuit 42 are conducted, power is supplied to the load device 3 from the power grid 2, when other power parameters meet the standard, the inverter 1 enters a grid-connected power generation mode, and the off-grid mode is automatically switched without communication with the inverter 1.
In an embodiment, when the power supply of the grid 2 is normal, the inverter 1 is in a grid-connected power generation state, the first switching circuit 41 and the second switching circuit 42 are in an on state, the third switching circuit 43A is in an off state, and the inverter 2 supplies power to the load device 3 and the grid 2. When the power grid 2 is powered down, the first switch circuit 41 and the second switch circuit 42 are in the off state, the inverter 1 enters the off-grid working mode, and the inverter 1 supplies power to the load device 3. In an embodiment, in the off-grid operating mode of the inverter 1, if the power grid 2 is powered on, the voltage monitored by the first voltage monitoring circuit changes and sends a first electric signal to the first switch control circuit 40, the first switch control circuit 40 detects the off-grid output voltage of the inverter 1, and the first switch circuit 41 and the second switch circuit 42 are off, at this time, the first switch control circuit 40 controls the third switch circuit 43A to be on, the preset frequency periodic switching on and off of the first resistor is realized, the inverter 1 detects that the output load meets the preset frequency periodic fluctuation, the off-grid is turned off, until the voltage monitored by the first voltage monitoring circuit is lower than the safe voltage, it is determined that the inverter 1 exits the off-grid mode, the first switch control circuit 40 controls the first switch circuit 41 and the second switch circuit 42 to be on, so that the power grid 2 supplies power to the load device, and after the first switch circuit 41 and the second switch circuit 42 are on, the third switch circuit 4a3 is turned off, and when other power parameters meet the standards, the inverter 1 performs grid connection, and enters a grid-connected power generation mode. In addition, the second voltage monitoring circuit 45 of the off-grid switching circuit 4 is used for detecting the voltage of the power grid 2, and when the voltage of the power grid 2 is abnormal and exceeds a preset range, the first switching circuit 41 and the second switching circuit 42 are controlled to be disconnected, so that the load is protected, and danger is prevented.
In the embodiment of the application, a grid-connected and off-grid switching circuit for an energy storage system is disclosed, and the grid-connected and off-grid switching circuit comprises a first switch control circuit, a first voltage monitoring circuit, a first switch circuit, a second switch circuit, a third switch circuit and an energy consumption load. The first switch circuit is connected between the power output end of the inverter and the power output end of the power grid, the second switch circuit is connected between the power ground end of the inverter and the power ground end of the power grid, the third switch circuit and the energy-consuming load are connected between the power output end of the inverter and the power ground end of the power grid, the first voltage monitoring circuit is used for monitoring the voltage output by the inverter, the first switch control circuit controls the disconnection or the connection of the first switch circuit, the second switch circuit and the third switch circuit according to the monitoring result of the first voltage monitoring circuit, because the inverter off-grid circuit is saved, the inverter grid-connected mode and the inverter off-grid mode share one output port, the size of the inverter is reduced, a double-power switch is also saved, and then the production cost of the energy storage system is reduced, and the energy storage system can be independently controlled and switched off-grid without communicating with an inverter, so that the energy storage system can be externally used independently.
Example two
Referring to fig. 3, it is a schematic diagram of a circuit structure of a grid-connected and grid-disconnected switching circuit according to another embodiment, where the grid-connected and grid-disconnected switching circuit is used to be connected between an inverter 1, a grid 2 and a load device 3 of an energy storage system, and control the energy storage system to switch a grid-connected or grid-disconnected state, so as to output a three-phase ac power output by the inverter 1 to the grid 2 or the load device 3. And the off-grid switching circuit comprises a third inverter connecting end, a fourth inverter connecting end, a fifth inverter connecting end, a sixth inverter connecting end, a third load connecting end, a fourth load connecting end, a fifth power grid connecting end, a sixth load connecting end, a third power grid connecting end, a fourth power grid connecting end, a fifth power grid connecting end and a sixth power grid connecting end. And the third inverter connecting end, the fourth inverter connecting end, the fifth inverter connecting end and the sixth inverter connecting end are respectively used for being connected with the A-phase power supply output end, the B-phase power supply output end, the C-phase power supply output end and the power supply grounding end of the inverter. The third load connection end, the fourth load connection end, the fifth power grid connection end and the sixth load connection end are respectively used for being connected with an input phase A power source end, an input phase B power source end, an input phase C power source end and an input power source grounding end of the load device. The third power grid connecting end, the fourth power grid connecting end, the fifth power grid connecting end and the sixth power grid connecting end are respectively used for being connected with a power grid A phase power output end, a power grid B phase power output end, a power grid C phase power output end and a power grid grounding end of a power grid. The grid-connected and off-grid switching circuit comprises a first switch control circuit 40, a first voltage monitoring circuit 44, a second voltage monitoring circuit 45, a fourth switch circuit 41A, a fifth switch circuit 41B, a sixth switch circuit 41C, a seventh switch circuit 42A, a third switch circuit 43A and an energy consumption load 43B. A fourth switching circuit 41A is connected between the third inverter connection and the third network connection, a fifth switching circuit 41B is connected between the fourth inverter connection and the fourth network connection, a sixth switching circuit 41C is connected between the fifth inverter connection and the fifth network connection, a seventh switching circuit 42A is connected between the fifth inverter connection and the fifth network connection, a third switching circuit 43A and a consumer load 43B are connected in series and are connected between the third inverter connection and the sixth inverter connection, or between the fourth inverter connection and the sixth inverter connection, or between the fifth inverter connection and the sixth inverter connection. In one embodiment, the dissipative load 43B comprises a resistor.
The first voltage monitoring circuit 44 is configured to monitor a voltage at the power output terminal of the inverter 1 and send a third electrical signal to the first switch control circuit 40 when the voltage is monitored, and the second voltage monitoring circuit 45 is configured to monitor a voltage at the power supply output terminal of the power grid 2 and send a fourth electrical signal to the first switch control circuit when the voltage is monitored. The first switch control circuit 40 is connected to the fourth switch circuit 41A, the fifth switch circuit 41B, the sixth switch circuit 41C, the seventh switch circuit 42A, and the third switch circuit 43A, for sending a fourth, fifth, sixth, seventh and eighth switch control electrical signal to the fourth, fifth, sixth, seventh and third switch circuits 41A, 41B, 41C, 42A and 43A, respectively, in response to the third electrical signal, the fourth, fifth, sixth, seventh and eighth switch control electrical signals being for turning on or off in response to the fourth, fifth, sixth, seventh and eighth switch control electrical signals, 41A, 41B, 41C, 42A and 43A, respectively.
In one embodiment, the grid-on/off switching circuit 4 further comprises a second voltage monitoring circuit 45 for monitoring the voltage at the grid power output terminal of the grid 2 and sending a fourth electrical signal to the first switch control circuit 40 when the voltage is monitored, the first switch control circuit 40 is further configured to send a ninth switch control electrical signal, a tenth switch control electrical signal, an eleventh switch control electrical signal, a twelfth switch control electrical signal and a thirteenth switch electrical signal to the fourth switch circuit 41A, the fifth switch circuit 41B, the sixth switch circuit 41C, the seventh switch circuit 42A and the third switch circuit 43A respectively in response to the fourth electrical signal, the fifth switch circuit 41B, the sixth switch circuit 41C, the seventh switch circuit 42A and the third switch circuit 43A respectively in response to the ninth switch control electrical signal, the tenth switch electrical signal, the seventh switch electrical signal, the sixth switch electrical, The eleventh, twelfth, and thirteenth switching control electrical signals are turned on or off. In an embodiment, the grid-connected and off-grid switching circuit 4 further includes an auxiliary power circuit 46 for providing power to the grid-connected and off-grid switching circuit 2. In an embodiment, the auxiliary power circuit 46 is connected to the grid 2 for obtaining power from the grid 2. In one embodiment, the grid-connected and off-grid switching circuit 4 further includes three overload protectors, and the overload protector 47A, the overload protector 47B and the overload protector 47C are respectively connected in series between the third inverter connection terminal and the third load connection terminal, the fourth inverter connection terminal and the fourth load connection terminal, and the fifth inverter connection terminal and the fifth load connection terminal, for providing overcurrent protection. In one embodiment, overload protectors 47A, 47B and 47C comprise fuses. In one embodiment, the fourth switch circuit 41A, the fifth switch circuit 41B, the sixth switch circuit 41C, the seventh switch circuit 42A, and/or the third switch circuit 43A includes a relay.
In this embodiment, when the power grid is powered off and the inverter is in an off-grid output state, if the power grid recovers power supply, if the first switch control circuit determines that the inverter is in the off-grid state by acquiring the voltage value of the output end of the inverter monitored by the first voltage monitoring circuit, the first switch controller controls the third switch circuit to periodically switch the resistance in the energy consuming load at the preset frequency, and the inverter detects that the off-grid load periodically changes according to the preset frequency and disconnects the off-grid output. If the first switch control circuit confirms that the inverter is closed and outputs off the grid by acquiring the voltage value of the output end of the inverter monitored by the first voltage monitoring circuit, the first switch controller controls the third switch circuit to be disconnected, then controls the fourth switch circuit, the fifth switch circuit, the sixth switch circuit and the seventh switch circuit to be connected, the power grid supplies power to the load device, when other power parameters meet the standard, the inverter enters a grid-connected power generation mode, and the grid-disconnected mode automatically switches the process and the grid-disconnected switching circuit does not need to communicate with the inverter. The auxiliary power supply circuit takes power from the power supply output end of the power grid to provide a control power supply required by the grid-connected and off-grid switching circuit 4. The operation of the first voltage monitoring circuit is the same as that of the first embodiment.
In an embodiment, when the power supply of the power grid is normal, the inverter is in a grid-connected power generation state, at this time, the fourth switching circuit, the fifth switching circuit, the sixth switching circuit and the seventh switching circuit are in a conducting state, the third switching circuit is in a disconnecting state, and the inverter supplies power to the load device and the power grid. When the power grid is powered off, the fourth switching circuit, the fifth switching circuit, the sixth switching circuit and the seventh switching circuit are in a disconnected state, the inverter enters an off-grid working mode, and the inverter supplies power to the load device at the moment. In an off-grid working mode of the inverter, if the power grid is powered on, the first voltage monitoring circuit monitors the output voltage of the inverter, the first switch control circuit confirms that the off-grid output voltage of the inverter and the fourth switch circuit, the fifth switch circuit, the sixth switch circuit and the seventh switch circuit are disconnected, at the moment, the first switch control circuit controls the third switch circuit to carry out preset frequency periodic switching on and off on the resistor, the inverter detects that the output load meets preset frequency periodic fluctuation, the off-grid is closed until the first voltage monitoring circuit monitors that the output voltage of the inverter is lower than the safety voltage, the inverter is confirmed to exit the off-grid mode, the first switch control circuit controls the fourth switch circuit, the fifth switch circuit, the sixth switch circuit and the seventh switch circuit to be connected so that the power grid supplies power to the load device, and after the fourth switch circuit, the fifth switch circuit, the sixth switch circuit and the seventh switch circuit are connected, and the third switch circuit is disconnected, and when other power parameters meet the standard, the inverter is connected to the grid, and the grid-connected power generation mode is entered. In addition, the grid-connected switching circuit is provided with a second voltage monitoring circuit, the grid voltage is detected, and the fourth switching circuit, the fifth switching circuit, the sixth switching circuit and the seventh switching circuit can be disconnected when the grid voltage is abnormal and exceeds the range, so that a load device is protected, and danger is prevented.
The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.
Claims (10)
1. The grid-connected and grid-disconnected switching circuit is used for being connected among an inverter, a power grid and a load device of an energy storage system, and is used for controlling the energy storage system to switch a grid-connected state or a grid-disconnected state so as to output an alternating current power supply output by the inverter to the power grid or the load device;
the grid-connected and off-grid switching circuit comprises a first inverter connecting end, a second inverter connecting end, a first load connecting end, a second load connecting end, a first power grid connecting end and a second power grid connecting end; the first inverter connecting end and the second inverter connecting end are respectively used for being connected with a power output end and a power grounding end of the inverter; the first load connecting end and the second load connecting end are respectively used for being connected with an input power supply end and an input power supply grounding end of the load device; the first power grid connection end and the second power grid connection end are respectively used for being connected with a power grid power supply output end and a power grid power supply grounding end of the power grid; the first inverter connection end is connected with the first load connection end;
the grid-connected and off-grid switching circuit further comprises a first switch control circuit, a first voltage monitoring circuit, a first switch circuit, a second switch circuit, a third switch circuit and an energy consumption load; the first switching circuit is connected between the first inverter connection and a first network connection; the second switching circuit is connected between the second inverter connection and a second grid connection; the third switch circuit is connected in series with the energy consumption load and then connected between the first inverter connecting end and the second inverter connecting end; the first voltage monitoring circuit is used for monitoring the voltage between the first inverter connecting end and the second inverter connecting end and sending a first electric signal to the first switch control circuit when the voltage is monitored;
the first switch control circuit is respectively connected with the first switch circuit, the second switch circuit and the third switch circuit and used for responding to the first electric signal and respectively sending a first switch control electric signal, a second switch control electric signal and a third switch control electric signal to the first switch circuit, the second switch circuit and the third switch circuit, and the first switch circuit, the second switch circuit and the third switch circuit are respectively used for responding to the first switch control electric signal, the second switch control electric signal and the third switch control electric signal to be switched on or switched off.
2. The grid-connected and off-grid switching circuit according to claim 1, further comprising a second voltage monitoring circuit for monitoring a voltage between the first grid connection terminal and the second grid connection terminal and sending a second electrical signal to the first switch control circuit when the monitored voltage is greater than a preset voltage, the first switch control circuit further being configured to send a fourth switch control electrical signal and a fifth switch control electrical signal to the first switch circuit and the second switch circuit, respectively, in response to the second electrical signal, the first switch circuit and the second switch circuit being configured to be turned on or off in response to the fourth switch control electrical signal and the fifth switch control electrical signal, respectively.
3. The on-grid and off-grid switching circuit as claimed in claim 2, further comprising an auxiliary power circuit for providing power to the on-grid and off-grid switching circuit.
4. The grid-connected to off-grid switching circuit of claim 1, further comprising an overload protector connected in series between the first inverter connection terminal and the first load connection terminal for providing overcurrent protection.
5. The grid-connected and off-grid switching circuit of claim 1, wherein the first, second, and/or third switching circuits comprise relays.
6. The grid-connected and grid-disconnected switching circuit is used for being connected among an inverter, a power grid and a load device of an energy storage system, controlling the energy storage system to switch a grid-connected state or a grid-disconnected state, and outputting a three-phase alternating current power supply output by the inverter to the power grid or the load device;
the grid-connected and off-grid switching circuit comprises a third inverter connecting end, a fourth inverter connecting end, a fifth inverter connecting end, a sixth inverter connecting end, a third load connecting end, a fourth load connecting end, a fifth power grid connecting end, a sixth load connecting end, a third power grid connecting end, a fourth power grid connecting end, a fifth power grid connecting end and a sixth power grid connecting end;
the third inverter connecting end, the fourth inverter connecting end, the fifth inverter connecting end and the sixth inverter connecting end are respectively used for being connected with an A-phase power supply output end, a B-phase power supply output end, a C-phase power supply output end and a power supply grounding end of the inverter;
the third load connecting end, the fourth load connecting end, the fifth power grid connecting end and the sixth load connecting end are respectively used for being connected with an input phase A power source end, an input phase B power source end, an input phase C power source end and an input power source grounding end of the load device;
the third power grid connecting end, the fourth power grid connecting end, the fifth power grid connecting end and the sixth power grid connecting end are respectively used for being connected with a power grid A phase power output end, a power grid B phase power output end, a power grid C phase power output end and a power grid grounding end of the power grid;
the grid-connected and off-grid switching circuit comprises a first switch control circuit, a first voltage monitoring circuit, a fourth switch circuit, a fifth switch circuit, a sixth switch circuit, a seventh switch circuit, a third switch circuit and an energy consumption load;
the fourth switching circuit is connected between the third inverter connection and the third grid connection, the fifth switching circuit is connected between the fourth inverter connection and the fourth grid connection, the sixth switching circuit is connected between the fifth inverter connection and the fifth grid connection, and the seventh switching circuit is connected between the fifth inverter connection and the fifth grid connection; the third switch circuit is connected in series with the energy consumption load and then connected between the connection end of the third inverter and the connection end of the sixth inverter, or connected between the connection end of the fourth inverter and the connection end of the sixth inverter, or connected between the connection end of the fifth inverter and the connection end of the sixth inverter;
the first voltage monitoring circuit is used for monitoring the voltage of the power output end of the inverter and sending a third electric signal to the first switch control circuit when the voltage is monitored; the first switch control circuit is respectively connected with the fourth switch circuit, the fifth switch circuit, the sixth switch circuit, the seventh switch circuit and the third switch circuit, and is used for responding to the third electric signal to respectively send a fourth switch control electric signal, a fifth switch control electric signal, a sixth switch control electric signal, a seventh switch control electric signal and an eighth switch control electric signal to the fourth switch circuit, the fifth switch circuit, the sixth switch control electric signal, the seventh switch control electric signal and the eighth switch control electric signal, and the fourth switch circuit, the fifth switch circuit, the sixth switch circuit, the seventh switch circuit and the third switch circuit are respectively used for responding to the fourth switch control electric signal, the fifth switch control electric signal, the sixth switch control electric signal, the seventh switch control electric signal and the eighth switch control electric signal to be turned on or turned off.
7. The grid-connected and off-grid switching circuit of claim 6, further comprising a second voltage monitoring circuit for monitoring a voltage at a grid power output of the power grid and sending a fourth electrical signal to the first switch control circuit when the voltage is monitored; the first switch control circuit is further configured to send a ninth switch control electrical signal, a tenth switch control electrical signal, an eleventh switch control electrical signal and a twelfth switch control electrical signal to the fourth switch circuit, the fifth switch circuit, the sixth switch circuit and the seventh switch circuit respectively in response to the fourth electrical signal, and the fourth switch circuit, the fifth switch circuit, the sixth switch circuit and the seventh switch circuit are configured to be turned on or off in response to the ninth switch control electrical signal, the tenth switch control electrical signal, the eleventh switch control electrical signal and the twelfth switch control electrical signal respectively.
8. The on-grid and off-grid switching circuit as claimed in claim 7, further comprising an auxiliary power circuit for providing power to said on-grid and off-grid switching circuit.
9. The grid-connected to grid-disconnected switching circuit according to claim 6, further comprising three overload protectors connected in series between said third inverter connection terminal and third load connection terminal, said fourth inverter connection terminal and fourth load connection terminal, and said fifth inverter connection terminal and fifth load connection terminal, respectively, for providing overcurrent protection.
10. The grid-connected and off-grid switching circuit of claim 6, wherein the fourth, fifth, sixth, seventh, and/or third switching circuit comprises a relay.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922151077.XU CN210806749U (en) | 2019-12-04 | 2019-12-04 | Grid-connected and grid-disconnected switching circuit for energy storage system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922151077.XU CN210806749U (en) | 2019-12-04 | 2019-12-04 | Grid-connected and grid-disconnected switching circuit for energy storage system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210806749U true CN210806749U (en) | 2020-06-19 |
Family
ID=71248952
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922151077.XU Active CN210806749U (en) | 2019-12-04 | 2019-12-04 | Grid-connected and grid-disconnected switching circuit for energy storage system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210806749U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112039068A (en) * | 2020-09-04 | 2020-12-04 | 深圳市尚科新能源有限公司 | Photovoltaic water lifting system |
| CN112952819A (en) * | 2021-03-19 | 2021-06-11 | 江苏固德威电源科技股份有限公司 | Split-phase output fast switching circuit and control method for restraining surge current adopted by same |
-
2019
- 2019-12-04 CN CN201922151077.XU patent/CN210806749U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112039068A (en) * | 2020-09-04 | 2020-12-04 | 深圳市尚科新能源有限公司 | Photovoltaic water lifting system |
| CN112952819A (en) * | 2021-03-19 | 2021-06-11 | 江苏固德威电源科技股份有限公司 | Split-phase output fast switching circuit and control method for restraining surge current adopted by same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108233346B (en) | Multi-terminal coordinated control protection system of flexible direct-current power grid | |
| US9018801B2 (en) | Photovoltaic system for feeding three-phase current into a power grid | |
| CN101673964B (en) | Modular UPS integrated power distribution system | |
| CN210806749U (en) | Grid-connected and grid-disconnected switching circuit for energy storage system | |
| WO2017127278A1 (en) | Interconnect and metering for renewables, storage and additional loads with electronically controlled disconnect capability for increased functionality | |
| CN112398175A (en) | Medium-voltage photovoltaic grid-connected inverter system and photovoltaic power generation system | |
| CN103560512A (en) | High-reliability closed loop wiring method of medium voltage distribution network | |
| CA3059572A1 (en) | Dc-dc converters having bullet terminals | |
| CN203481822U (en) | Closed loop power supply model of medium voltage 10 kilovolt power distribution network | |
| CN213754084U (en) | Dual-power supply system adopting power supplies with different grounding modes | |
| CN210780097U (en) | Low-voltage power distribution system | |
| CN110504670B (en) | Power supply system and power supply method of direct-current power distribution network | |
| KR20170042070A (en) | Apparatus and method for preventing disaster caused by short-circuit in electric power systems | |
| CN205992744U (en) | A kind of 220 kilovolts of booster stations systems | |
| CN213906376U (en) | Differentiated standby power control structure | |
| CN216720910U (en) | Direct-current power supply circuit | |
| CN214505432U (en) | Fusing and switch combined intelligent fuse | |
| CN220586243U (en) | Direct current short circuit breaking combiner box | |
| CN217983231U (en) | Cloud distribution intelligent circuit breaker | |
| CN113726000B (en) | Power supply device and power supply method thereof | |
| CN114069569B (en) | Method for reducing electric quantity loss of distribution box in fault state | |
| CN211930316U (en) | DC cabinet of wind-solar hybrid power generation system | |
| CN218940767U (en) | Power supply switching system and power supply | |
| RU2755660C1 (en) | Four-pin multicontact switching system with independent control of three power contact groups | |
| CN211376559U (en) | Circuit breaker |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20210128 Address after: 518101 2 / F and 3 / F, building 4, xibianling Jiayu Company Industrial Zone, Shangwu village, Shiyan street, Bao'an District, Shenzhen City, Guangdong Province Patentee after: SHENZHEN GROWATT NEW ENERGY Co.,Ltd. Address before: 518000 Guangdong Province Shenzhen Baoan District Shiyan Street Longteng community Guanghui road 28 Jiayu Industrial Zone office building a, first floor East, third floor, factory building B Patentee before: GROWATT NEW ENERGY TECHNOLOGY Co.,Ltd. |
|
| TR01 | Transfer of patent right | ||
| CP03 | Change of name, title or address |
Address after: 518101 floor a401, 4-13, building a, Sino German European Industrial Demonstration Park, Hangcheng Avenue, guxing community, Xixiang street, Bao'an District, Shenzhen, Guangdong Patentee after: Shenzhen Growatt New Energy Technology Co.,Ltd. Address before: 518101 2 / F and 3 / F, building 4, xibianling Jiayu Company Industrial Zone, Shangwu village, Shiyan street, Bao'an District, Shenzhen City, Guangdong Province Patentee before: SHENZHEN GROWATT NEW ENERGY Co.,Ltd. |
|
| CP03 | Change of name, title or address |