CN221633434U

CN221633434U - Off-grid switching system

Info

Publication number: CN221633434U
Application number: CN202323543923.5U
Authority: CN
Inventors: 王江; 高伟; 李峥; 冯玉川
Original assignee: Chengdu Qingtao New Energy Technology Co ltd
Current assignee: Chengdu Qingtao New Energy Technology Co ltd
Priority date: 2023-12-25
Filing date: 2023-12-25
Publication date: 2024-08-30
Anticipated expiration: 2033-12-25

Abstract

The application relates to a parallel-to-off-grid switching system which is used for switching power supply to a load from a grid-connected end to power supply to the load from an off-grid end; the switching circuit of the switching system comprises a first input circuit and a second input circuit, wherein the output end of the first input circuit is connected with the output end of the second input circuit and then is connected with the input end of a load; the input end of the first input circuit is connected with the grid-connected end, and the input end of the second input circuit is connected with the off-grid end; the grid-connected end comprises an energy storage power supply output end and a power supply end for supplying power after the power storage power supply output end is connected in parallel, and the off-grid end comprises a power supply end for directly supplying power by the energy storage power supply. The parallel-to-off network switching system can automatically realize power connection in two different states of parallel-to-network and off-network, has a simple connection mode, does not need to carry out additional control strategies and algorithm limitations, greatly reduces switching time during parallel-to-off network switching, does not cause power interruption or power grid fluctuation due to parallel-to-off network switching, and improves stability and reliability of power supply.

Description

Off-grid switching system

Technical Field

The application relates to the technical field of power equipment, in particular to a parallel-off-grid switching system.

Background

Along with the transformation of energy structures, the proportion of new energy sources such as wind energy, solar energy and the like in an electric power system is increasing. And a grid-connected power generation mode is generally adopted among the new energy power supply systems so as to provide stable and reliable power for a power grid. However, when the grid fails or requires maintenance, it is necessary to be able to quickly and smoothly switch from grid-connected mode to off-grid mode to ensure continuous supply of important loads.

In the existing switching equipment in the off-grid switching process, due to the limitation of a control strategy and an algorithm, long switching time is required, and power supply interruption or power grid fluctuation can be caused to influence the stability and reliability of power supply. What is needed is a system for fast and smooth off-grid switching.

Disclosure of utility model

Based on this, it is necessary to provide a system for switching between off-network and on-network, which can perform switching between off-network and on-network quickly and smoothly.

The application provides a parallel-to-off-grid switching system which is used for switching power supply to a load from a grid-connected end to power supply to the load from an off-grid end;

The switching system comprises a switching device for switching the switching device,

The switching circuit comprises a first input circuit and a second input circuit, and the output end of the first input circuit is connected with the output end of the second input circuit and then is connected with the input end of the load;

The input end of the first input circuit is connected with the grid-connected end, and the input end of the second input circuit is connected with the off-grid end;

The grid-connected end comprises an energy storage power supply output end and a power supply end for supplying power after the power grid power supply output end is connected in parallel, and the off-grid end comprises a power supply end for directly supplying power by the energy storage power supply.

In one embodiment, the energy storage power supply is connected with the power grid power supply through a grid-connected circuit, the grid connection of the energy storage power supply and the power grid power supply is realized after the grid-connected circuit is conducted, and the off-grid of the energy storage power supply and the power grid power supply is realized after the grid-connected circuit is disconnected;

When the grid-connected circuit is conducted, the first input circuit is conducted;

Or when the grid-connected circuit is disconnected, the second input circuit is connected.

In one embodiment, the first input circuit comprises a first switch and the second input circuit comprises a second switch;

In a grid-connected state, the first switch is closed, and the second switch is opened, so that the grid-connected end is connected with a load;

In the off-grid state, the first switch is opened and the second switch is closed so that the off-grid end is connected with a load.

In one embodiment, the energy storage power supply includes a regulating circuit and an energy storage element, the regulating circuit is used for regulating direct current of the energy storage element into alternating current, wherein:

the input end of the adjusting circuit is connected with the output end of the energy storage element, and the output end of the adjusting circuit is used as the output end of the energy storage power supply.

In one embodiment, the adjusting circuit includes a spike absorbing circuit, an inverter circuit, a filter circuit, and a protection circuit, wherein:

The peak absorption circuit is connected with the energy storage part and is used for receiving the direct current provided by the energy storage part and outputting peaks of the direct current to be absorbed so as to obtain smooth direct current;

The inverter circuit is connected with the peak absorption circuit and used for converting the smoothed direct current into alternating current;

the filtering circuit is connected with the inverter circuit and used for filtering the alternating current points to obtain filtered alternating current;

And the protection circuit is respectively connected with the filter circuit and the switching circuit and is used for carrying out reverse connection protection on alternating current.

In one embodiment, the peak absorbing circuit comprises a first diode, a first resistor and a third switch, wherein the anode of the first diode is connected with the first ends of the energy storage power supply and the third switch respectively, the cathode of the first diode is connected with the first end of the first resistor, and the second end of the first resistor is connected with the second ends of the inverter circuit and the third switch respectively.

In one embodiment, the inverter circuit comprises a full-bridge power module, the full-bridge power module comprises a first combined switch, a second capacitor and a second resistor which are connected in parallel, the first combined switch and the second combined switch comprise switching units which are sequentially connected in series, and each switching unit comprises a switching tube and a diode which is connected in anti-parallel with the switching tube.

In one embodiment, the filter circuit is an LC filter circuit.

In one embodiment, the protection circuit includes a first rectifying diode and a second rectifying diode, a first end of the first rectifying diode is connected to a second end of the filter circuit and the second rectifying diode, and a second end of the first rectifying diode is connected to a first end of the grid-connected circuit and the second rectifying diode.

In one embodiment, the grid-connected circuit comprises a lightning protection circuit, an isolation circuit, a metering circuit and a grid-connected switch, wherein:

the lightning protection circuit is connected with the output end of the energy storage power supply and used for carrying out lightning protection on the energy storage power supply;

The isolation circuit is connected with the lightning protection circuit and the metering circuit and is used for isolating the energy storage power supply from the power grid power supply;

The metering circuit is used for being connected with the power circuit and metering the electric quantity output after the energy storage power supply is connected with the power circuit;

the grid-connected switch is connected in series in the grid-connected circuit, and the grid-connected switch is closed or opened to realize grid connection or grid disconnection of the energy storage power supply and the power grid power supply.

The grid-connected and off-grid switching system is used for switching power supply from a grid-connected end to a load to an off-grid end to supply power to the load, and comprises a switching circuit, wherein the switching circuit comprises a first input circuit and a second input circuit, and the output end of the first input circuit is connected with the output end of the second input circuit and then is connected with the input end of the load; the input end of the first input circuit is connected with the grid-connected end, and the input end of the second input circuit is connected with the off-grid end; the grid-connected end comprises an energy storage power supply output end and a power supply end for supplying power after the power grid power supply output end is connected in parallel, and the off-grid end comprises a power supply end for directly supplying power by the energy storage power supply. The parallel-to-off network switching system can automatically realize power connection in two different states of parallel-to-network and off-network, has a simple connection mode, does not need to carry out additional control strategies and algorithm limitations, greatly reduces switching time during parallel-to-off network switching, does not cause power interruption or power grid fluctuation due to parallel-to-off network switching, and improves stability and reliability of power supply.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a schematic diagram of a circuit module of an off-grid switching system according to an embodiment;

FIG. 2 is a schematic circuit block diagram of an off-grid switching system according to another embodiment;

FIG. 3 is a schematic circuit block diagram of an off-grid switching system according to another embodiment;

fig. 4 is a circuit diagram of an off-network switching system according to an embodiment.

Reference numerals illustrate:

100. A power supply circuit; 101. a grid-connected end; 102. off-grid end; 110. a power grid power supply; 120. an energy storage power supply; 200. a switching circuit; 210. a first switch; 220. a second switch; 230. an adjusting circuit; 231. an energy storage member; 2302. a spike absorbing circuit; 2304. an inverter circuit; 2306. a filter circuit; 2308. a protection circuit; 240. a grid-connected circuit; 2402. a metering circuit; 2404. an isolation circuit; 2406. a lightning protection circuit; 2407. a grid-connected switch; 300. and a control circuit.

Detailed Description

In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. Embodiments of the application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the application. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.

It is understood that "at least one" means one or more and "a plurality" means two or more. "at least part of an element" means part or all of the element.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.

In the increasingly developed new energy and in combination with the environmental protection requirement, the popularization of clean energy application, the proportion of new energy such as wind energy, solar energy and the like in an electric power system is higher and higher. The new energy power supply is mainly provided with two connection modes of grid connection and off-grid at present, in short, grid connection means that a power supply generated by a new energy system is directly connected with an electric load and is not connected with a power grid, correspondingly, the off-grid indicates that the power supply generated by the new energy system is also connected with the power grid, and is connected with the electric load after comprehensive dispatching.

As shown in fig. 1, the off-grid switching system of an embodiment is configured to switch between a grid-connected terminal 101 to supply power to a load and an off-grid terminal 102 to supply power to the load; the switching system comprises a switching circuit 200, wherein the switching circuit 200 comprises a first input circuit and a second input circuit, and the output end of the first input circuit is connected with the output end of the second input circuit and then is connected with the input end of a load; the input end of the first input circuit is connected with the grid-connected end 101, and the input end of the second input circuit is connected with the off-grid end 102; the grid-connected end 101 includes a power supply end for supplying power after the output end of the energy storage power supply 120 and the output end of the grid power supply 110 are connected in parallel, and the off-grid end 102 includes a power supply end for directly supplying power to the energy storage power supply 120. The energy storage power supply 120 and the grid power supply 110 form a power supply circuit 100.

The switching system, the power circuit 100 includes a grid power supply 110 and an energy storage power supply 120; the switching circuit 200 is respectively connected with the power supply circuit 100 and the load, and the switching circuit 200 is used for connecting the power grid 110 and the energy storage 120 with the load in the case of grid connection and is used for switching and connecting the energy storage 120 with the load in the case of off-grid connection.

As shown in fig. 1, when the off-grid switching system works, the system is further provided with a control circuit 300, the control circuit 300 may be a processing chip or a signal processing circuit, when the power supply 110 of the power grid needs to be overhauled or adjusted, the power supply circuit 100 sends an off-grid control signal to the control circuit 300, which indicates that the connection between the power supply 110 of the power grid and the energy storage power supply 120 needs to be disconnected, and the energy storage power supply 120 is used for supplying power alone, and the control circuit 300 controls the switching circuit 200 to adjust the connection between the grid-connected end 101 and the load according to the off-grid control signal, so as to switch the off-grid end 102 and the load; correspondingly, when the power required by the load is large or the energy storage power supply 120 is insufficient for energy supply, a grid-connected control signal is sent to the control circuit 300, which indicates that the grid power supply 110 and the energy storage power supply 120 need to be combined together to supply power to the load, and the control circuit 300 controls the switching circuit 200 to adjust the connection between the grid-connected terminal 101 and the load according to the grid-connected control signal, so as to switch to connect the grid power supply 110 and the energy storage power supply 120 to the load after grid connection.

The grid-connected and off-grid switching system of the embodiment can automatically realize power connection in two different states of grid connection and off-grid connection, is simple in connection mode, and is provided with the switching circuit 200 between the power circuit 100 and a load, so that the off-grid power supply switching can be quickly performed through the switching circuit 200 according to the off-grid or on-grid requirements, the limitation of an additional control strategy and an algorithm is not needed, the switching time during the off-grid switching is reduced, the power supply interruption or the power grid fluctuation caused by the off-grid switching is avoided, and the stability and the reliability of the power supply are improved.

In one embodiment, as shown in fig. 1, the switching circuit 200 includes a first switch 210 and a second switch 220, a first end of the first switch 210 is connected to both the grid power supply 110 and the energy storage power supply 120, and a second end of the first switch 210 is used to connect to a load; a first end of the second switch 220 is connected to the energy storage power source 120, and a second end of the second switch 220 is used for being connected to a load; wherein the first switch 210 and the second switch 220 have opposite operating states.

As shown in the figure, the switching circuit 200 realizes switching control by means of switches, and since the present embodiment switches the connection between the power supply circuit 100 and the load in two different control modes, the corresponding switching circuit 200 includes two switches to be controlled respectively. The first switch 210 is connected with the grid power supply 110 and the energy storage power supply 120 after being connected, and is used for realizing connection control in a grid-connected mode; the second switch 220 is connected to the energy storage power source 120, and is used for implementing connection control in the off-grid mode. Since the first switch 210 and the second switch 220 correspond to different modes, respectively, the first switch 210 and the second switch 220 exhibit opposite operating states. Further, in a specific embodiment, the switching system is specifically configured to: in the grid-connected state, the first switch 210 is closed and the second switch 220 is opened, so that the grid power supply 110 and the energy storage power supply 120 are connected with the load; in an off-grid state, the first switch 210 is opened and the second switch 220 is closed to connect the stored energy power source 120 to the load.

As shown in the previous example, the first switch 210 and the second switch 220 exhibit opposite operating states, that is, the second switch 220 needs to be kept in an open state when the first switch 210 is closed, and the first switch 210 needs to be protected in an open state when the second switch 220 is closed. Specifically, in the grid-connected state, the first switch 210 is closed to connect the grid power supply 110 and the energy storage power supply 120 to the load, and at this time, the second switch 220 is kept in an open state; in the off-grid state, the energy storage power source 120 is connected to the load by closing the second switch 220, while the first switch 210 remains in the off-state.

Illustratively, the first switch 210 and the second switch 220 each employ an electromagnetic relay switch, except that the first switch 210 is a normally closed switch and the second switch 220 is a normally open switch; that is, in the grid-connected state, the first switch 210 is in a conducting state, the second switch 220 is in a disconnected state, and in the off-grid condition, the first switch 210 is in a disconnected state, and the second switch 220 is in a conducting state; the first switch 210 and the second switch 220 each comprise a control coil and a knife switch, the control coil and the grid-connected terminal 101 provide working voltages; when the grid-connected terminal 101 is powered off, the knife of the first switch 210 opens the knife of the second switch 220 to be closed, so that the switching between grid connection and grid disconnection is realized.

As shown in fig. 2, in one embodiment, the energy storage power supply 120 is connected to the power grid 110 through a grid-connected circuit 240, the grid-connected circuit 240 is turned on to achieve grid connection between the energy storage power supply 120 and the power grid 110, and the grid-connected circuit 240 is turned off to achieve off-grid connection between the energy storage power supply 120 and the power grid 110; when the grid-connected circuit 240 is turned on, the first input circuit is turned on; or, when the grid-connected circuit 240 is off, the second input circuit is on.

As shown in fig. 2, in one embodiment, the stored energy power source 120 includes a regulating circuit 230 and a stored energy element 231, wherein: the adjusting circuit 230 is configured to adjust the dc power of the energy storage element 231 to ac power, and specifically, an input end of the adjusting circuit 230 is connected to an output end of the energy storage element 231, and an output end of the adjusting circuit 230 is used as an output end of the energy storage power source 120.

For example, the adjusting circuit 230 may be used to adjust the dc power output by the energy storage element 231, such as amplitude adjustment, ac/dc conversion, smoothing adjustment, etc., and the dc power output by the energy storage element 231 may be adjusted and converted by the adjusting circuit 230 for better grid connection with the grid power source 110 or for providing to a load.

In an exemplary embodiment, as shown in fig. 3, the adjusting circuit 230 includes a spike absorbing circuit 2302, an inverter circuit 2304, a filter circuit 2306 and a protection circuit 2308, where the spike absorbing circuit 2302 is connected to the energy storage element 231 and is configured to receive the direct current provided by the energy storage element 231 and absorb an output spike of the direct current to obtain a smoothed direct current; the inverter circuit 2304 is connected to the spike absorbing circuit 2302, and is configured to convert the smoothed direct current into alternating current; the filter circuit 2306 is connected to the inverter circuit 2304, and is configured to filter the alternating current to obtain a filtered alternating current; the protection circuit 2308 is connected to the filter circuit 2306 and the switching circuit 200, respectively, for reverse connection protection of the ac power.

The peak absorbing circuit 2302 is configured to absorb the transient peak and output a dc with a stable state. The energy storage member 231 outputs a generally direct current, which is converted when transmitted to a load, and the inverter circuit 2304 converts the direct current into an alternating current. The filter circuit 2306 is configured to filter the inverted ac power to remove an interference signal. The protection circuit 2308 performs reverse connection protection for the switching circuit 200, preventing the circuit from being damaged due to reverse connection of the power supply.

During operation, the dc power output by the energy storage element 231 is absorbed by the peak absorbing circuit 2302, smoothed, then inverted by the inverter circuit 2304, converted into ac power, filtered by the filter circuit 2306, and connected to the load by the switching circuit 200, and meanwhile, the adjusting circuit 230 is also protected against reverse connection by the protection circuit 2308, so as to realize the protection of charge and discharge.

It will be appreciated that the regulation circuit 230 may take other forms, not limited to the forms already mentioned in the above embodiments, as long as it can perform the function of regulating the output dc power of the energy storage member 231.

As shown in fig. 4, in an exemplary embodiment, the spike absorbing circuit 2302 includes a first diode, a first resistor and a third switch, an anode of the first diode is connected to first ends of the energy storage power source 120 and the third switch, respectively, a cathode of the first diode is connected to a first end of the first resistor, and a second end of the first resistor is connected to second ends of the inverter circuit 2304 and the third switch, respectively.

It will be appreciated that the spike absorbing circuit 2302 may take other forms, not limited to those already mentioned in the above embodiments, as long as it is capable of achieving the function of absorbing spikes of the power signal output.

In another embodiment, as shown in fig. 4, the inverter circuit 2304 includes a full-bridge power module including a first combination switch, a second capacitor and a second resistor connected in parallel, each of the first combination switch and the second combination switch including a switching unit connected in series in turn, each of the switching units including a switching tube and a diode connected in anti-parallel with the switching tube.

Taking fig. 4 as an example, the inverter circuit 2304 converts a dc signal to obtain an ac signal. The inverter circuit 2304 includes a power module for converting a dc electrical signal into an ac electrical signal by controlling on and off of the switching tube, and outputting the ac electrical signal to a load. The ac power signal output from the inverter circuit 2304 includes a three-phase output signal.

It is to be understood that the inverter circuit 2304 may take other forms, not limited to the forms already mentioned in the above embodiments, as long as it can achieve the function of converting a direct-current power signal into an alternating-current power signal.

In another embodiment, as shown in FIG. 4, the filter circuit 2306 is an LC filter circuit.

The filter circuit 2306 of the present embodiment is an LC filter circuit, and other types of filter circuits may be designed in practical applications. Because the output alternating current signals comprise three-phase output signals, an inductor and a capacitor are connected in parallel to each phase of output alternating current signals so as to realize the filtering processing of the alternating current signals and obtain the filtered alternating current signals.

It will be appreciated that the filter circuit 2306 may take other forms, not limited to those already mentioned in the above embodiments, as long as it can perform the function of filtering the converted ac signal.

In another embodiment, as shown in fig. 4, the protection circuit 2308 includes a first rectifying diode and a second rectifying diode, wherein a first end of the first rectifying diode is connected to the second ends of the filtering circuit 2306 and the second rectifying diode, respectively, and a second end of the first rectifying diode is connected to the first ends of the grid-connected circuit 240 and the second rectifying diode, respectively.

The protection circuit 2308 of the present embodiment includes a rectifier diode connected between the positive and negative poles of the power supply, which allows only current to flow from the positive pole to the negative pole, preventing reverse current from passing. The protection circuit 2308 can effectively protect the switching circuit 200, prevent damage caused by reverse connection of a power supply of the circuit, and prevent reverse current from passing through a rectifier diode when reverse connection occurs, so that the safety and stability of the circuit are ensured.

It will be appreciated that the protection circuit 2308 may take other forms, not limited to the forms already mentioned in the above embodiments, as long as it can achieve the anti-reverse connection function of the switching circuit 200.

Still taking fig. 2 and fig. 4 as an example, in an exemplary embodiment, the energy storage power supply 120 is connected to the power grid 110 through the grid-connected circuit 240, the grid-connected circuit 240 is turned on to implement grid connection between the energy storage power supply 120 and the power grid 110, and the grid-connected circuit 240 is turned off to implement off-grid connection between the energy storage power supply 120 and the power grid 110; when the grid-connected circuit 240 is turned on, the first input circuit is turned on; or, when the grid-connected circuit 240 is off, the second input circuit is on. The grid-connected circuit 240 comprises a lightning protection circuit 2406, an isolation circuit 2404, a metering circuit 2402 and a grid-connected switch 2407, wherein the lightning protection circuit 2406 is used for being connected with the power circuit 100 to carry out lightning protection on the power circuit 100; the isolation circuit 2404 is connected with the lightning protection circuit 2406 and the metering circuit 2402, and is used for isolating power signals; the meter circuit 2402 is connected to the power supply circuit 100, and meters the power signal.

Illustratively, the lightning protection circuit 2406 may be a lightning protection device connected by a circuit breaker, where the lightning protection circuit 2406 is used to prevent the strong current and voltage generated by lightning from damaging the switching device or the power supply system, causing a safety accident, and providing protection for personal safety and power equipment. The isolation circuit 2404 may be a circuit breaker for breaking the connection of the circuit when needed, improving the safety and stability of the circuit. The metering circuit 2402 may be a metering ammeter and a corresponding circuit breaker, and the metering circuit 2402 is configured to meter the electric energy output by the power circuit 100, so as to further analyze according to the data of the metering circuit 2402.

Illustratively, as shown in FIG. 4, the grid tie switch 2407 includes QF1 and/or an output control switch QE2; it will be appreciated that the grid-connected switch 2407 may take other forms, not limited to the forms already mentioned in the above embodiments, and that the grid-connected switch 2407 is connected in series in the grid-connected circuit 240, and the specific position of the series connection is not limited; as long as the functions of realizing grid connection or off-grid of the energy storage power supply 120 and the power grid power supply 110 can be achieved.

It will be appreciated that the grid-tie circuit 240 may take other forms, not limited to the forms already mentioned in the above embodiments, as long as it is capable of achieving the protection function of the power circuit 100.

The grid-connected and off-grid switching system provided by the application has the advantages that the volume is small, the structure is simple, the grid-connected mode can be automatically switched to the off-grid mode when the power grid fails or needs to be maintained, the continuous power supply to the load is ensured, and the risk of power supply interruption caused by the power grid failure is reduced. In addition, the present application performs rapid and smooth switching of the power supply in the power supply circuit 100, further improving the stability and reliability of power supply.

In the description of the present specification, reference to the term "some embodiments," "other embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be assessed as that of the appended claims.

Claims

1. The parallel-to-off network switching system is characterized in that the parallel-to-on network switching system is used for switching power supply to a load from a grid-connected end to power supply to the load from a grid-off end;

the switching system comprises a switching unit which is connected with the switching unit,

2. The switching system according to claim 1, wherein the energy storage power supply is connected to the grid power supply through a grid-connected circuit, the grid-connected circuit is turned on to realize grid connection between the energy storage power supply and the grid power supply, and the grid-connected circuit is turned off to realize off-grid connection between the energy storage power supply and the grid power supply;

3. The switching system of claim 2, wherein the first input circuit comprises a first switch and the second input circuit comprises a second switch;

in a grid-connected state, closing the first switch and opening the second switch so as to connect the grid-connected end with the load;

And in the off-grid state, opening the first switch and closing the second switch so as to connect the off-grid end with the load.

4. The switching system of claim 2, wherein the stored energy power source comprises a regulating circuit and a stored energy element, the regulating circuit configured to regulate a direct current of the stored energy element to an alternating current, wherein:

5. The switching system of claim 4, wherein the regulation circuit comprises a spike absorbing circuit, an inverter circuit, a filter circuit, and a protection circuit, wherein:

The peak absorbing circuit is connected with the energy storage piece and is used for receiving the direct current provided by the energy storage piece and absorbing the output peak of the direct current to obtain smooth direct current;

the inverter circuit is connected with the peak absorbing circuit and is used for converting the smoothed direct current into alternating current;

The filtering circuit is connected with the inverter circuit and is used for filtering the alternating current to obtain filtered alternating current;

And the protection circuit is respectively connected with the filter circuit and the switching circuit and is used for carrying out reverse connection protection on the alternating current.

6. The switching system of claim 5, wherein the spike absorbing circuit comprises a first diode, a first resistor and a third switch, wherein an anode of the first diode is connected to the energy storage power supply and a first end of the third switch, respectively, a cathode of the first diode is connected to the first end of the first resistor, and a second end of the first resistor is connected to the inverter circuit and a second end of the third switch, respectively.

7. The switching system of claim 5, wherein the inverter circuit comprises a full-bridge power module comprising a first combination switch, a second capacitor, and a second resistor connected in parallel, the first combination switch and the second combination switch each comprising a switching unit in series in sequence, each switching unit comprising a switching tube and a diode antiparallel with the switching tube.

8. The switching system of claim 5, wherein the filter circuit is an LC filter circuit.

9. The switching system of claim 5, wherein the protection circuit comprises a first rectifying diode and a second rectifying diode, a first end of the first rectifying diode being connected to the filter circuit and a second end of the second rectifying diode, respectively, and a second end of the first rectifying diode being connected to the grid-tie circuit and a first end of the second rectifying diode, respectively.

10. The switching system of claim 2, wherein the grid-tie circuit comprises a lightning protection circuit, an isolation circuit, a metering circuit, and a grid-tie switch, wherein:

The metering circuit is used for being connected with the power supply circuit and metering the electric quantity output after the energy storage power supply is connected with the power supply;