CN218633354U - Grid-connected and off-grid switching device and grid-connected and off-grid switching system - Google Patents
Grid-connected and off-grid switching device and grid-connected and off-grid switching system Download PDFInfo
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- CN218633354U CN218633354U CN202223212523.1U CN202223212523U CN218633354U CN 218633354 U CN218633354 U CN 218633354U CN 202223212523 U CN202223212523 U CN 202223212523U CN 218633354 U CN218633354 U CN 218633354U
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Abstract
The application provides a grid-connected and off-grid switching device and a grid-connected and off-grid switching system, which comprise a first alternating current contactor and a second alternating current contactor, wherein the first alternating current contactor comprises a first coil and a first main contact switch, the first main contact switch is arranged between a load interface and an emergency load of an inverter, the first coil is arranged between the load interface and the first main contact switch, and the first coil is connected with the load interface and the first main contact switch in parallel; the second alternating current contactor comprises a second coil and a second main contact switch, the second main contact switch is arranged between a grid-connected point and an emergency load of a power grid, and the second coil is connected with an alternating current interface and the grid-connected point of the inverter in parallel. The power supply of the emergency load can be guaranteed to a certain extent, the control is performed without an extra control circuit, the inverter is not required to participate in and switch control or feed back some control signals from the off-grid, and the control method and the control device are simple to operate, low in development cost and high in fault tolerance rate.
Description
Technical Field
The present application relates to the field of power supply technologies, and in particular, to a grid-connected and grid-disconnected switching device and a grid-connected and grid-disconnected switching system.
Background
At present, an energy storage inverter with a grid-connected and off-grid switching function is in a grid-connected state and supplies power to an emergency load when a power grid is normal, and the energy storage inverter can be switched to an off-grid state after the power grid fails and continues to supply power to the emergency load; however, the existing on-grid and off-grid switching schemes often have the following disadvantages: firstly, if the power grid normally supplies power but the energy storage inverter has a fault, the power can not be supplied to the emergency load, and the normal use of the emergency load is difficult to ensure; secondly, the existing grid-connected and off-grid switching scheme usually adopts a control circuit to control the switching of a relay or a contactor, and an energy storage inverter is required to participate in grid-connected and off-grid switching control or feed back most control signals, so that the operation is complex, the development cost is high, and the fault tolerance rate of the system is low.
SUMMERY OF THE UTILITY MODEL
The present application is directed to solving at least one of the problems in the prior art. Therefore, the grid-connected and off-grid switching device and the grid-connected and off-grid switching system can guarantee the power supply of the emergency load to a certain extent, do not need an additional control circuit to control, do not need an inverter to participate in grid-connected and off-grid switching control or feed back some control signals, and are simple to operate, low in development cost and high in fault tolerance rate.
In a first aspect, an embodiment of the present application provides a grid-connected and off-grid switching apparatus, including: the first alternating current contactor comprises a first coil and a first main contact switch, the first main contact switch is arranged between a load interface and an emergency load of the inverter, the first coil is arranged between the load interface and the first main contact switch, and the first coil is connected with the load interface and the first main contact switch in parallel; the second alternating current contactor comprises a second coil and a second main contact switch, the second main contact switch is arranged between a grid-connected point of a power grid and an emergency load, and the second coil is connected with an alternating current interface of the inverter and the grid-connected point in parallel.
According to some embodiments of the present application, the operating state of the grid-connected and off-grid switching device includes at least one of: supplying power to the emergency load through the power grid when the first coil is de-energized and the first main contact switch is open, the second coil is energized and the second main contact switch is closed; and under the conditions that the first coil is electrified, the first main contact switch is closed, the second coil is not electrified, and the second main contact switch is opened, supplying power to the emergency load through the load interface of the inverter.
According to some embodiments of the present application, the first main contact switch and the second main contact switch are both normally open contact switches.
According to some embodiments of the present application, the grid-connected and off-grid switching device further comprises at least one of:
the first alternating current contactor further comprises a first auxiliary contact switch, the first auxiliary contact switch is connected with the second coil in series, and the first auxiliary contact switch is a normally closed contact switch;
the second ac contactor further includes a second auxiliary contact switch connected in series with the first coil, and the second auxiliary contact switch is a normally closed contact switch.
According to some embodiments of the application, the one end of the second main contact switch connected to the grid-connected point is also for connecting to a non-emergency load.
In a second aspect, an embodiment of the present application provides a grid-connected and off-grid switching system, which includes an inverter and the grid-connected and off-grid switching device of the first aspect, wherein the inverter is provided with an ac interface and a load interface, the ac interface is connected in parallel with the second coil and is connected to a grid-connected point of a power grid, and the load interface is connected in parallel with the first coil and is connected to an emergency load through the first main contact switch.
According to some embodiments of the present application, the grid-connected and off-grid switching system further comprises a detection device, the detection device is connected to the inverter and the grid, and the detection device is configured to detect a power supply state of the grid.
According to some embodiments of the application, the detection device comprises at least one of: current transformer, electric energy meter.
According to some embodiments of the application, the inverter is provided with a first relay for controlling the ac interface to be turned on or off.
According to some embodiments of the application, the inverter is provided with a second relay for controlling the load interface to be switched on or off.
According to the technical scheme of the embodiment of the application, the following technical effects are included but not limited: the embodiment of the application comprises a first alternating current contactor and a second alternating current contactor, wherein the first alternating current contactor comprises a first coil and a first main contact switch, the first main contact switch is arranged between a load interface and an emergency load of an inverter, the first coil is arranged between the load interface and the first main contact switch, and the first coil is connected with the load interface and the first main contact switch in parallel; the second alternating current contactor comprises a second coil and a second main contact switch, the second main contact switch is arranged between a grid-connected point of a power grid and the emergency load, and the second coil is connected with an alternating current interface of the inverter and the grid-connected point in parallel. Firstly, when the power grid normally supplies power, the second coil can be powered on through the grid-connected point and triggers the second main contact switch to be closed, so that the power grid can directly supply power to the emergency load through the second main contact switch without indirectly supplying power to the emergency load through the inverter, and therefore, even if the inverter fails, the power supply of the emergency load cannot be influenced, and the power supply of the emergency load can be ensured to a certain extent; in addition, the grid-connected and off-grid switching of the inverter can be realized through the loss of power of the coil and the opening and closing of the main contact switch, an additional control circuit is not needed for control, the inverter is not needed to participate in grid-connected and off-grid switching control or feed back some control signals, and the method and the device are simple to operate, low in development cost and high in fault tolerance rate.
Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the example serve to explain the principles of the invention.
Fig. 1 is a schematic structural diagram of a system architecture platform for performing a grid-to-grid handover method according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of an on-grid and off-grid switching system according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a grid-connected and off-grid switching system according to another embodiment of the present application;
fig. 4 is an overall flowchart of an on-grid and off-grid handover method according to an embodiment of the present application.
Detailed Description
Reference will now be made in detail to the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.
In the description of the present application, it is to be understood that the positional descriptions, such as the directions of up, down, front, rear, left, right, etc., referred to herein are based on the directions or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and thus, should not be construed as limiting the present application.
In the description of the present application, the meaning of a plurality is one or more, the meaning of a plurality is two or more, and larger, smaller, larger, etc. are understood as excluding the present number, and larger, smaller, inner, etc. are understood as including the present number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present application, unless otherwise expressly limited, terms such as set, mounted, connected and the like should be construed broadly, and those skilled in the art can reasonably determine the specific meaning of the terms in the present application by combining the detailed contents of the technical solutions.
Under some conditions, the energy storage inverter with the grid-connected and off-grid switching function is in a grid-connected state and supplies power to the emergency load when the power grid is normal, and the energy storage inverter can be switched to an off-grid state after the power grid fails and continues to supply power to the emergency load; however, the existing on-grid and off-grid switching schemes often have the following disadvantages: firstly, if the power grid normally supplies power but the energy storage inverter has a fault, the power can not be supplied to the emergency load, and the normal use of the emergency load is difficult to ensure; secondly, the existing grid-connected and off-grid switching scheme often adopts a control circuit to control the switching of a relay or a contactor, and an energy storage inverter is required to participate in grid-connected and off-grid switching control or feed back most of control signals, so that the operation is complex, the development cost is high, and the fault tolerance rate of the system is low.
Based on the above situation, the embodiment of the application provides a grid-connected and off-grid switching device and a grid-connected and off-grid switching system, which not only can ensure the power supply of an emergency load to a certain extent, but also do not need an additional control circuit for control, and do not need an inverter to participate in grid-connected and off-grid switching control or feed back some control signals, and the grid-connected and off-grid switching device is simple in operation, low in development cost and high in fault tolerance rate.
The embodiments of the present application will be further explained with reference to the drawings.
As shown in fig. 1, fig. 1 is a schematic diagram of a system architecture platform for performing an on-grid and off-grid handover method according to an embodiment of the present application.
The system architecture platform 100 of the present embodiment includes one or more processors 110 and a memory 120, and fig. 1 illustrates one processor 110 and one memory 120 as an example.
The processor 110 and the memory 120 may be connected by a bus or other means, such as the bus connection shown in FIG. 1.
The memory 120, which is a non-transitory computer readable storage medium, may be used to store non-transitory software programs as well as non-transitory computer executable programs. Further, the memory 120 may include high speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, memory 120 optionally includes memory 120 located remotely from processor 110, which may be connected to system architecture platform 100 via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
Those skilled in the art will appreciate that the device architecture illustrated in FIG. 1 does not constitute a limitation on system architecture platform 100, and may include more or fewer components than shown, or some components in combination, or a different arrangement of components.
In the system architecture platform 100 shown in fig. 1, the processor 110 may be configured to call the on-grid and off-grid switching program stored in the memory 120, so as to implement the on-grid and off-grid switching method.
Based on the hardware structure of the system architecture platform, various embodiments of the grid-connected and off-grid switching device and the grid-connected and off-grid switching system are provided.
As shown in fig. 2, fig. 2 is a schematic structural diagram of an on-grid and off-grid switching system according to an embodiment of the present application. The grid-connected and off-grid switching device can be shown in a dashed box a in fig. 2, and is used for implementing the grid-connected and off-grid state switching of the inverter 400.
In an embodiment, the first ac contactor includes, but is not limited to, a first coil 210 and a first main contact switch 220, wherein one end of the first main contact switch 220 is used for connecting to a load interface of the inverter 400, the other end of the first main contact switch 220 is used for connecting to an emergency load 510, in addition, the first coil 210 is disposed between the load interface and the first main contact switch 220, and the first coil 210 is connected in parallel with the load interface and the first main contact switch 220.
In an embodiment, the second AC contactor includes, but is not limited to, a second coil 310 and a second main contact switch 320, wherein one end of the second main contact switch 320 is used for connecting to a grid connection point of a power grid, and the other end of the second main contact switch 320 is used for connecting to an emergency load 510, and in addition, the second coil 310 is disposed between an AC interface and the grid connection point and connected in parallel with an AC (Alternating Current) interface and the grid connection point of the inverter 400.
It is understood that, regarding the above-mentioned first main contact switch 220 and the second main contact switch 320, both may be normally open contact switches, specifically, in case the first coil 210 is in a power loss state, the first main contact switch 220 is in a normally open state; in the event that the second coil 310 is de-energized, the second main contact switch 320 is in a normally open state.
The first ac contactor and the second ac contactor described above operate according to the following principles: when the coil of the alternating current contactor is electrified, the coil current can generate a magnetic field, then the generated magnetic field can enable the static iron core to generate electromagnetic attraction to attract the movable iron core and drive the alternating current contactor to act, the normally closed contact is opened, the normally open contact is closed, and the normally closed contact and the normally open contact are linked.
In one embodiment, the terminal of the second main contact switch 320 connected to the grid-connected point is also used for connecting to the non-emergency load 520, and the non-emergency load 520 and the emergency load 510 are coupled through the second main contact switch 320.
In an embodiment, the working states of the grid-connected and off-grid switching devices include, but are not limited to, the following two types:
the first working state: corresponding to the state of supplying power to the emergency load 510 on the power grid, in the first operating state, the load interface of the inverter 400 is disconnected, so that the first coil 210 loses power, and the first main contact switch 220 is in the disconnected state because the first coil 210 loses power; meanwhile, the second coil 310 is powered through the grid-connected point, so as to pull in the second main contact switch 320 to close the second main contact switch 320, and thus the power grid can directly supply power to the emergency load 510 through the second main contact switch 320.
In the first operating state, the ac interface of the inverter 400 is in a conducting state to implement grid connection processing, and at this time, the load interface of the inverter 400 is in a disconnecting state.
The second working state: corresponding to the state that the inverter 400 supplies power to the emergency load 510, in the second operating state, the ac interface of the inverter 400 is disconnected, so that the second coil 310 loses power, and the second main contact switch 320 is in the disconnected state because the second coil 310 loses power; meanwhile, the load interface of the inverter 400 is turned on, and the first coil 210 is powered through the load interface, so as to pull in the first main contact switch 220 to close the first main contact switch 220, thereby enabling the inverter 400 to perform power supply processing on the emergency load 510 through the first main contact switch 220.
In the second operating state, the ac interface of the inverter 400 is in the off state to ensure that the second coil 310 cannot receive power from the ac interface, and the off-grid processing of the inverter 400 is simultaneously implemented, at this time, the load interface of the inverter 400 is in the on state, so that the inverter 400 can sequentially perform power supply processing on the emergency load 510 through the load interface and the first main contact switch 220.
In addition, as shown in fig. 3, fig. 3 is a schematic structural diagram of a grid-connected and off-grid switching system according to another embodiment of the present application.
In one embodiment, the first ac contactor further includes, but is not limited to, a first auxiliary contact switch 230, wherein one end of the first auxiliary contact switch 230 is connected to the second coil 310, and the other end of the first auxiliary contact switch 230 is connected to the ac interface and the grid-connected point.
It is to be understood that, with regard to the above-mentioned first auxiliary contact switch 230, specifically, a normally closed contact switch, specifically, in the case where the first coil 210 is in a power loss state, the first auxiliary contact switch 230 is in a normally closed state.
In one embodiment, the second ac contactor further includes, but is not limited to, a second auxiliary contact switch 330, wherein one end of the second auxiliary contact switch 330 is connected to the first coil 210, and the other end of the second auxiliary contact switch 330 is connected to the load interface and the first main contact switch 220.
It is to be understood that, with regard to the above-described second auxiliary contact switch 330, specifically, a normally closed contact switch, specifically, in the case where the second coil 310 is in a power loss state, the second auxiliary contact switch 330 is in a normally closed state.
It should be noted that, because the first auxiliary contact switch 230 and the second auxiliary contact switch 330 are additionally provided, the first ac contactor and the second ac contactor are interlocked, so that it is ensured that the load interface is in an open circuit state when the power grid is powered on, and the load interface only supplies power to the emergency load 510 after the power grid is powered off, thereby ensuring the power supply duration and the power supply reliability of the emergency load 510.
According to the technical scheme of the grid-connected and off-grid switching device of the embodiment of the application, firstly, when the power grid normally supplies power, the second coil 310 can be powered through a grid-connected point and triggers the second main contact switch 320 to be closed, so that the power grid can directly supply power to the emergency load 510 through the second main contact switch 320 without indirectly supplying power to the emergency load 510 through the inverter 400, and therefore, even if the inverter 400 fails, the power supply of the emergency load 510 cannot be influenced, and the power supply of the emergency load 510 can be ensured to a certain extent; in addition, the grid-connected and off-grid switching of the inverter 400 can be realized through the loss of power of the coil and the opening and closing of the main contact switch, an additional control circuit is not needed for control, the inverter 400 is not needed to participate in grid-connected and off-grid switching control or feed back some control signals, and the grid-connected and off-grid switching control system is simple in operation, low in development cost and high in fault tolerance rate.
As shown in fig. 2 and fig. 3, the grid-connected and off-grid switching system of the embodiment of the present application includes, but is not limited to, an inverter 400 and the grid-connected and off-grid switching device of any of the above embodiments, the inverter 400 is provided with an ac interface and a load interface, wherein the ac interface is connected in parallel with the second coil 310, and the ac interface is connected to a grid-connected point of a power grid; in addition, a load interface is connected in parallel with the first coil 210, and the load interface is connected to the emergency load 510 through the first main contact switch 220.
It is to be understood that, regarding the inverter 400 described above, the inverter 400 may be a light storage inverter, and may be another type of inverter 400, and the embodiment of the present application does not specifically limit the type of the inverter 400.
In an embodiment, the grid-connected and off-grid switching system of the embodiment of the present application further includes, but is not limited to, a detection device, wherein one end of the detection device is connected to the power grid, and the other end of the detection device is connected to the inverter 400, and the detection device is capable of detecting the current power supply state of the power grid, for example, the detection device is capable of detecting whether the power grid is currently powered or not.
It should be noted that the inverter 400 according to the embodiment of the present application is further provided with a detection interface (not shown in the drawings), and the detection interface is connected to the detection device.
It should be noted that, the detection device may be the electric energy meter 610, the current transformer 620, or another type of detection device, and the embodiment of the present application does not specifically limit the type of the detection device. When the detection device is the electric energy meter 610, the inverter 400 can detect the current power supply state of the power grid through the electric energy meter 610; when the detecting device is the current transformer 620, the inverter 400 can detect the current power supply state of the power grid through the current transformer 620.
In one embodiment, in order to control the ac interface, the inverter 400 is further provided with a first relay (not shown), wherein the first relay can control the ac interface to be turned on or off. Specifically, when the first relay is closed, the alternating current interface is switched on in response; when the first relay is opened, the AC interface responds to the opening.
In one embodiment, in order to control the load interface, the inverter 400 is further provided with a second relay (not shown), wherein the second relay can control the load interface to be switched on or off. Specifically, when the second relay is closed, the load interface is turned on in response; when the second relay is opened, the load interface will respond to the opening.
The first relay and the second relay described above operate according to the following principles: when the relay works, the electromagnet is electrified to suck the armature down for contact, and the working circuit is closed. When the electromagnet is powered off, the electromagnet loses magnetism, and the spring pulls the armature up to cut off the working circuit.
According to the technical scheme of the grid-connected and off-grid switching system of the embodiment of the application, firstly, when the power grid normally supplies power, the second coil 310 can be powered on through a grid-connected point and triggers the second main contact switch 320 to be closed, so that the power grid can directly supply power to the emergency load 510 through the second main contact switch 320 without indirectly supplying power to the emergency load 510 through the inverter 400, and therefore, even if the inverter 400 fails, the power supply of the emergency load 510 cannot be influenced, and the power supply of the emergency load 510 can be guaranteed to a certain extent; in addition, the grid-connected and off-grid switching of the inverter 400 can be realized through the loss of power of the coil and the opening and closing of the main contact switch, an additional control circuit is not needed for control, the inverter 400 is not needed to participate in grid-connected and off-grid switching control or feed back some control signals, and the method and the device are simple to operate, low in development cost and high in fault tolerance rate.
It should be noted that, since the grid-connected and off-grid switching system according to the embodiment of the present application includes the grid-connected and off-grid switching device according to the above embodiment, specific implementation manners and technical effects of the grid-connected and off-grid switching system according to the embodiment of the present application may refer to specific implementation manners and technical effects of the grid-connected and off-grid switching device according to any one of the above embodiments.
In an embodiment, the current power supply state of the power grid is detected by a detection device so as to judge whether the current power supply state of the power grid is a normal power supply state or an abnormal power failure state; when the power grid normally supplies power, the load interface of the inverter is disconnected, so that the first coil loses power, and the first main contact switch is in a disconnected state due to the fact that the first coil loses power; meanwhile, the second coil can be electrified through a grid connection point, so that the second main contact switch is attracted to be closed, and the power grid can directly supply power to the emergency load through the second main contact switch. When the power grid is abnormally powered off, the alternating current interface of the inverter is disconnected, so that the second coil loses power, and the second main contact switch is in a disconnected state due to the fact that the second coil loses power; meanwhile, a load interface of the inverter can be conducted, the first coil can be electrified through the load interface, and therefore the first main contact switch is attracted to be closed, and the inverter can supply power to the emergency load through the first main contact switch.
In an embodiment, when the power grid normally supplies power, the ac interface is disconnected through the first relay, and the load interface is disconnected through the second relay in the embodiment of the present application, specifically, since signals of the power grid and the inverter are not synchronized yet, the ac interface needs to be disconnected through the first relay first, and then the ac interface is closed again after the voltage phase and the frequency of the power grid are detected and phase-locked; in addition, because the inverter does not need to supply power to the emergency load through the load interface, the load interface can be disconnected through the second relay in the embodiment of the application, so that the safety and the reliability are ensured.
When the power supply state is the power supply state, the second auxiliary contact switch is turned off in addition to the actuation of the second main contact switch after the second coil is powered through the grid-connected point.
It should be noted that, when the power supply state is the power-off state, after the first coil is powered on, the first auxiliary contact switch is also turned off in addition to the attraction of the first main contact switch.
In one embodiment, when the power grid normally supplies power, after the second coil gets power through the grid-connected point and attracts the second main contact switch, the embodiment of the application also detects the voltage phase and the frequency of the power grid, performs phase-locking processing based on the detected voltage phase and frequency, and finally conducts the alternating current interface through attracting by the first relay, thereby realizing grid-connected processing of the inverter.
The first relay described above operates in the following manner: when the relay works, the electromagnet is electrified to suck the armature down for contact, and the working circuit is closed. When the electromagnet is powered off, the electromagnet loses magnetism, and the spring pulls the armature up to cut off the working circuit.
In an embodiment, when the power grid is abnormally powered off, the current output state of the alternating current interface is detected firstly, if the alternating current interface does not output current, the inverter is indicated to operate normally, then the alternating current interface is disconnected, so that the second coil loses power and cannot attract the second main contact switch, and at the moment, the second main contact switch is in the disconnected state.
In an embodiment, when a power grid is abnormally powered off, the embodiment of the present application may first detect a current output state of an ac interface, and if the ac interface has a current output, it indicates that an inverter is abnormally operated, and at this time, the embodiment of the present application may disconnect the ac interface and perform alarm processing.
It can be understood that, regarding the above alarm processing mode, the alarm may be performed by sounding through a speaker, the alarm may also be performed by flashing an illumination lamp or lighting a red light, or the alarm may also be performed through a remote communication mode, and the alarm processing mode in the embodiment of the present application is not particularly limited.
In an embodiment, when the power grid is abnormally powered off and after the load interface is turned on through the second relay, the current output state of the load interface is detected first, if the current output exists at the load interface, the inverter is indicated to operate normally, and at the moment, the inverter supplies power to the emergency load through the load interface, that is, the inverter is indicated to be in an off-grid output state; if the load interface has no current output, the inverter is indicated to be abnormal in operation, the inverter cannot supply power for the emergency load, and the load interface is disconnected and alarm processing is performed in the embodiment of the application.
Based on the above embodiments of the grid-connected and off-grid switching method, the following respectively proposes the overall embodiments of the grid-connected and off-grid switching method of the present application.
As shown in fig. 4, fig. 4 is an overall flowchart of a grid-connected and off-grid handover method according to an embodiment of the present application.
In an embodiment, an overall process of the grid-connected and off-grid switching method in the embodiment of the present application includes, but is not limited to, the following steps:
step one, after an inverter is incorporated into a power grid, detecting whether the power grid is electrified or not through a communication or CT interface of an electric energy meter;
step two, if the power grid is electrified, an AC interface and a load interface relay which are arranged in the inverter are disconnected, and the step three is carried out; if the power grid is dead, entering a sixth step;
step three, keeping the auxiliary contact of the alternating current contactor KM1 normally closed, electrifying a coil of the alternating current contactor KM2, attracting the main contact KM2, and disconnecting the main contact KM 1;
step four, the power grid supplies power to the non-emergency load and the emergency load;
step five, detecting the voltage phase and frequency of the power grid by the AC interface of the inverter, locking the phase, attracting the relay of the AC interface to be connected to the power grid, and returning to the step one;
step six, the inverter self-checks whether the AC interface has current output, if so, the inverter judges that the operation is abnormal, and disconnects the relay of the AC interface and gives an alarm; if no current is output, entering the seventh step;
step seven, the AC interface relay of the inverter is disconnected, the KM2 coil loses power, and the KM2 main contact is disconnected;
step eight, closing a load interface relay, electrifying a coil of an alternating current contactor KM1, and closing a main contact of KM 1;
step nine, whether the current output exists at the self-checking load interface of the inverter or not is judged, and if the current output exists at the self-checking load interface of the inverter, the inverter is judged to be output in an off-grid mode; if no current is output, the operation is judged to be abnormal, and the relay of the inverter load interface is disconnected and an alarm is given.
Specifically, the embodiment of the application has the following technical effects: firstly, the grid-connected and off-grid switching of the inverter can be realized by adopting the logic cooperation of the alternating current contactor, the inverter is not required to participate in grid-connected and off-grid switching control or feed back some control signals, the fault tolerance rate of equipment is improved, the control difficulty of the equipment is reduced, and the development cost is reduced. Secondly, after the inverter is damaged, the power supply of the emergency load can also be ensured. And finally, the alternating current contactor KM1 and the alternating current contactor KM2 are interlocked, so that the load interface is in an open circuit state when the power grid is electrified, and the load interface only supplies power to the emergency load after the power grid is electrified, so that the power supply duration and the power supply reliability of the emergency load are ensured.
Based on the above system architecture platform, the grid-connected and off-grid switching device and the grid-connected and off-grid switching system, the following respectively provide various embodiments of the controller and the power supply system of the present application.
In addition, an embodiment of the present application provides a controller including: a processor, a memory, and a computer program stored on the memory and executable on the processor.
The processor and memory may be connected by a bus or other means.
It should be noted that the controller in this embodiment may include a processor and a memory as in the embodiment shown in fig. 1, both belong to the same application concept, and therefore both have the same implementation principle and beneficial effect, and are not described in detail herein.
The non-transitory software programs and instructions required to implement the grid-connected and off-grid switching method of the above embodiments are stored in the memory, and when executed by the processor, the grid-connected and off-grid switching method of the above embodiments is performed.
According to the technical scheme of the controller, firstly, when the power grid normally supplies power, the second coil can be electrified through the grid-connected point and triggers the second main contact switch to be closed, so that the power grid can directly supply power to the emergency load through the second main contact switch without indirectly supplying power to the emergency load through the inverter, and therefore, even if the inverter fails, the power supply of the emergency load cannot be influenced, and the power supply of the emergency load can be guaranteed to a certain extent; in addition, the grid-connected and off-grid switching of the inverter can be realized through the loss of power of the coil and the opening and closing of the main contact switch, an additional control circuit is not needed for control, the inverter is not needed to participate in grid-connected and off-grid switching control or feed back some control signals, and the grid-connected and off-grid switching control system is simple in operation, low in development cost and high in fault tolerance rate.
It is to be noted that, since the controller according to the embodiment of the present application is capable of executing the grid-connected and off-grid switching method according to the above embodiment, reference may be made to the specific implementation and technical effects of the grid-connected and off-grid switching method according to any one of the above embodiments.
In addition, an embodiment of the present application provides a power supply system, which includes the grid-connected and off-grid switching system of any one of the above embodiments.
According to the technical scheme of the power supply system, firstly, when the power grid normally supplies power, the second coil can be electrified through the grid-connected point and triggers the second main contact switch to be closed, so that the power grid can directly supply power to the emergency load through the second main contact switch without indirectly supplying power to the emergency load through the inverter, and therefore, even if the inverter fails, the power supply of the emergency load cannot be influenced, and the power supply of the emergency load can be guaranteed to a certain extent; in addition, the grid-connected and off-grid switching of the inverter can be realized through the loss of power of the coil and the opening and closing of the main contact switch, an additional control circuit is not needed for control, the inverter is not needed to participate in grid-connected and off-grid switching control or feed back some control signals, and the method and the device are simple to operate, low in development cost and high in fault tolerance rate.
It should be noted that, since the power supply system according to the embodiment of the present application includes the grid-connected and off-grid switching system according to the above-mentioned embodiment, and the grid-connected and off-grid switching system includes the grid-connected and off-grid switching device according to the above-mentioned embodiment, reference may be made to the specific implementation and technical effects of the grid-connected and off-grid switching device according to any one of the above-mentioned embodiments.
While the preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and such equivalent modifications or substitutions are included in the scope of the present invention defined by the claims.
Claims (10)
1. An on-grid and off-grid switching device, comprising:
the first alternating current contactor comprises a first coil and a first main contact switch, the first main contact switch is arranged between a load interface and an emergency load of the inverter, the first coil is arranged between the load interface and the first main contact switch, and the first coil is connected with the load interface and the first main contact switch in parallel;
the second alternating current contactor comprises a second coil and a second main contact switch, the second main contact switch is arranged between a grid-connected point of a power grid and an emergency load, and the second coil is connected with an alternating current interface of the inverter and the grid-connected point in parallel.
2. The grid-connected and off-grid switching device according to claim 1, wherein the operating state of the grid-connected and off-grid switching device comprises at least one of:
supplying power to the emergency load through the power grid when the first coil is de-energized and the first main contact switch is open, the second coil is energized and the second main contact switch is closed;
and under the conditions that the first coil is electrified, the first main contact switch is closed, the second coil is not electrified, and the second main contact switch is opened, supplying power to the emergency load through the load interface of the inverter.
3. The grid-connected switching device of claim 2, wherein the first main contact switch and the second main contact switch are both normally open contact switches.
4. The grid-connected and off-grid switching device according to claim 1, further comprising at least one of:
the first alternating current contactor further comprises a first auxiliary contact switch, the first auxiliary contact switch is connected with the second coil in series, and the first auxiliary contact switch is a normally closed contact switch;
the second ac contactor further includes a second auxiliary contact switch, which is connected in series with the first coil, and the second auxiliary contact switch is a normally closed contact switch.
5. The grid-connected and off-grid switching device according to claim 1, wherein the end of the second main contact switch connected to the grid-connected point is further configured to be connected to a non-emergency load.
6. A grid-connected and off-grid switching system, characterized by comprising an inverter and the grid-connected and off-grid switching device of any one of claims 1 to 5, the inverter being provided with an AC interface connected in parallel with the second coil and to a grid-connected point of a power grid and a load interface connected in parallel with the first coil and to an emergency load through the first main contact switch.
7. The grid-connected and off-grid switching system according to claim 6, further comprising a detection device connected to the inverter and the grid, the detection device being configured to detect a power supply status of the grid.
8. The grid-connected and off-grid switching system according to claim 7, wherein the detecting means comprises at least one of: current transformer, electric energy meter.
9. The grid-connected and off-grid switching system according to claim 6, wherein the inverter is provided with a first relay for controlling the AC interface to be turned on or off.
10. The grid-connected and off-grid switching system according to claim 6, wherein the inverter is provided with a second relay, and the second relay is used for controlling the load interface to be switched on or switched off.
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| CN202223212523.1U CN218633354U (en) | 2022-11-30 | 2022-11-30 | Grid-connected and off-grid switching device and grid-connected and off-grid switching system |
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| CN202223212523.1U CN218633354U (en) | 2022-11-30 | 2022-11-30 | Grid-connected and off-grid switching device and grid-connected and off-grid switching system |
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