A light storage device

Abstract

The application discloses a kind of optical storage equipment, comprising: AC-DC converter and parallel off-grid conversion device;AC-DC converter is connected to the first end of direct current source, and the second end of AC-DC converter is connected with power grid through parallel off-grid control device;AC-DC converter is used to carry out AC-DC conversion between direct current source and power grid in operating state;Parallel off-grid conversion device includes: first switching device, for when closing, the connection between direct current source and power grid is turned on;Or, in the case of opening, disconnect;Digital signal processing module is used to obtain the parallel off-grid control state of optical storage equipment and the switching state of first switching device;In the case where parallel off-grid control state and the switching state of first switching device do not match, stop driving AC-DC converter;AC-DC converter enters shutdown state, and disconnects.

Description

TECHNICAL FIELD

[0001] The present application relates to, but is not limited to, the field of power grid, and in particular to a light storage device. BACKGROUND

[0002] The light storage device needs to be connected to the power grid for power storage and power supply on one hand, and needs to independently generate and store power in an off-grid state on the other hand. The light storage device is provided with a contactor or a relay and other switching devices for controlling the connection or disconnection between the light storage device and the power grid to realize grid connection and off-grid. In order to increase off-grid safety, the switching devices usually need to be redundantly configured, so that in the case of failure of one switching device, the other redundant switching device can be used to realize safe off-grid of the light storage device; however, the contactor is relatively high in cost, and redundancy will result in high cost of the light storage device. SUMMARY

[0003] The embodiments of the present application provide a light storage device which can realize safe off-grid without configuring redundant switching devices, and can reduce the cost of the light storage device.

[0004] The technical solution of the present application is implemented as follows:

[0005] The embodiments of the present application provide a light storage device, comprising:

[0006] An AC / DC converter and a grid connection and off-grid conversion device; a first end of the AC / DC converter is connected to a DC source, and a second end of the AC / DC converter is connected to a power grid through the grid connection and off-grid conversion device;

[0007] The AC / DC converter is used to perform AC / DC conversion between the DC source and the power grid in a running state.

[0008] The grid connection and off-grid conversion device comprises:

[0009] A first switching device is used to conduct the connection between the DC source and the power grid when closed, or to disconnect the connection when opened.

[0010] A digital signal processing module is used to acquire a grid connection and off-grid control state of the light storage device and a switching state of the first switching device; in the case that the grid connection and off-grid control state does not match the switching state of the first switching device, the driving of the AC / DC converter is stopped; the AC / DC converter enters a shutdown state, and the connection is disconnected.

[0011] The embodiment of the present application provides a kind of optical storage equipment, since digital signal processing module can obtain the parallel off-grid control state of optical storage equipment and the switching state of first switching device, in the case where both do not match, determine that the switching state of first switch cannot realize parallel off-grid control state, can stop driving AC-DC converter.It is said that optical storage equipment can be stopped by AC-DC converter, to disconnect the connection between DC source and power grid, realize safe off-grid.So, optical storage equipment cooperates by software and hardware, only needs to set up a switching device to realize off-grid, can reduce the cost of optical storage equipment. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 A structure schematic diagram of optical storage equipment in a related art is provided for the embodiment of the present application;

[0013] Figure 2 A structure schematic diagram of optional optical storage equipment is provided for the embodiment of the present application;

[0014] Figure 3 A structure schematic diagram of optional optical storage equipment is provided for the embodiment of the present application;

[0015] Figure 4 A structure schematic diagram of optional optical storage equipment is provided for the embodiment of the present application;

[0016] Figure 5 A structure schematic diagram of optional optical storage equipment is provided for the embodiment of the present application;

[0017] Figure 6 A structure schematic diagram of optional optical storage equipment is provided for the embodiment of the present application;

[0018] Figure 7 A structure schematic diagram of optional optical storage equipment is provided for the embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be described in further detail below in conjunction with the drawings, the described embodiments should not be regarded as limitation to the present application, all other embodiments obtained by those skilled in the art without doing creative work belong to the scope of protection of the present application.

[0020] In the following description, "some embodiments" are related to the description of a subset of all possible embodiments, but it can be understood that "some embodiments" can be the same subset or different subset of all possible embodiments, and can be combined with each other without conflict.

[0021] In the following description, the terms "first", "second", "third", etc. are merely used to distinguish similar objects, and do not represent a specific order or sequence of the objects. It is understood that the "first", "second", "third", etc. can be interchanged in a specific order or sequence as allowed, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0022] Unless otherwise defined, 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 in this application is for the purpose of describing embodiments of this application only, and is not intended to be limiting of this application.

[0023] Unless otherwise defined, 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 in this application is for the purpose of describing embodiments of this application only, and is not intended to be limiting of this application.

[0024] To facilitate understanding of the present application, before the embodiments of the present application are described, the application background in the embodiments of the present application is described.

[0025] Figure 1 The structure of a light storage device in the related art is shown as follows, Figure 1 As shown in the figure, the light storage device 101 includes an AC / DC converter 12, a main switching device K11 and an auxiliary switching device K12. The first end of the AC / DC converter 12 is connected with a DC source 102, and the second end of the AC / DC converter 12 is connected with a power grid 103 through the switching devices K11 and K12. A load access point is arranged between the main switching device K11 and the AC / DC converter 12, for accessing a load, to realize power supply of the light storage device 101 to the load. Since the main switching device K11 and the auxiliary switching device K12 are connected in series, in the case that the main switching device K11 fails and cannot be disconnected, the auxiliary switching device K12 can be used to realize off-grid, to ensure off-grid safety, wherein the main switching device K11 and the auxiliary switching device K12 are respectively controlled by a corresponding digital signal processor (DSP) to control the switching state. However, for a light storage device with large power, the main switching device K11 and the auxiliary switching device K12 need to use contactors, and the cost of the contactors is high, resulting in high cost of the light storage device.

[0026] To solve the above problems, the embodiments of the present application provide a light storage device, which can realize safe off-grid of the light storage device without auxiliary switching devices, and can reduce the cost. Figure 2 A structure schematic diagram of a light storage device provided by the embodiments of the present application is shown in the figure, Figure 2As shown, the light storage device can include: an AC / DC converter 22 and an on / off grid conversion device 23; a first end of the AC / DC converter 22 is connected with the DC power source 10, and a second end of the AC / DC converter 22 is connected with the power grid 30 through the on / off grid conversion device 23; the AC / DC converter 22 is used to perform AC / DC conversion between the DC power source 10 and the power grid 30 in a running state; the on / off grid conversion device 23 includes: a first switching device K21, which is used to connect the DC power source 10 and the power grid when closed, or disconnect the connection when opened; a digital signal processing module 232, which is used to obtain an on / off grid control state of the light storage device and a switching state of the first switching device K21; in a case where the on / off grid control state does not match the switching state of the first switching device K21, stop driving the AC / DC converter 22; the AC / DC converter 22 enters a shutdown state and disconnects the connection.

[0027] In the embodiment of the present application, the AC / DC converter 22 is driven by the digital signal processing module 232 to send a driving signal, so that the AC / DC converter is in a running state. In the running state of the AC / DC converter 22, if the first switching device K21 is closed, the DC power source 10 is connected with the power grid 30 through the AC / DC converter 22, and grid connection is realized; if the first switching device K21 is opened, the DC power source 10 can supply power to the load through the AC / DC converter 22.

[0028] In the embodiment of the present application, the digital signal processing module 232 can obtain an on / off grid control state. The on / off grid control state is used to represent the working state of the light storage device and the switching state between different working states; the working state of the light storage device includes grid connection and off-grid.

[0029] In the embodiment of the present application, the working state of the light storage device 20 can be indicated by an on / off grid control signal, so that the digital signal processing module 232 can determine the on / off grid control state according to the on / off grid control signal. For example, the light storage device 20 is in grid connection, and the received on / off grid control signal indicates that the light storage device is switched to off-grid, so that the digital signal processing module 232 can determine that the on / off grid control state is grid connection to off-grid. After the light storage device 20 is switched to off-grid, if no other on / off grid control signal is received, the off-grid state can be maintained.

[0030] In the embodiment of the present application, the different working states of the light storage device 20 need to match the switching state of the first switching device K21 to be realized; the switching state of the first switching device K21 includes closing and opening. For example, the light storage device 20 is off-grid or on standby, corresponding to the first switching device K21 being opened; or the light storage device 20 is on-grid, corresponding to the first switching device K21 being closed. However, in the case that the first switching device K21 cannot be normally closed or opened, it will cause the light storage device to fail to be off-grid or on-grid, that is, it cannot realize the partial off-grid or on-grid control state. The unachievable off-grid or on-grid control state does not match the switching state of the first switching device K21. For example, the first switching device K21 is implemented as a control relay, and in the case that the control relay contact is short-circuited, the first switching device K21 can only remain in the closed state and cannot be normally opened. At this time, if the off-grid or on-grid control state of the light storage device 20 is off-grid, it does not match the switching state of the first switching device K21.

[0031] In the embodiment of the present application, in the case that the off-grid or on-grid control state and the switching state of the first switching device K21 do not match, the digital signal processing module 232 can stop driving the AC converter 22, so that the AC-DC converter 22 enters a shutdown state. In the case that the AC-DC converter 22 is shut down, the connection between the DC power source 10 and the power grid 30 is disconnected, realizing off-grid.

[0032] In the embodiment of the present application, the AC-DC converter 22 is internally provided with a power electronic switching device. The power electronic switching device is closed under the driving of the digital signal processing module 232, so that the AC-DC converter 22 normally operates; the power electronic switching device will be opened in the case that it is not driven by the digital signal processing module 232, so that the AC-DC converter 22 is shut down, thereby disconnecting the current path between the DC power source 10 and the power grid 30, realizing off-grid.

[0033] It can be understood that since the digital signal processing module 232 can acquire the off-grid or on-grid control state of the light storage device 20 and the switching state of the first switching device K21, in the case that the two do not match, it is determined that the switching state of the first switching device K21 cannot realize the off-grid or on-grid control state, and the driving of the AC-DC converter 22 can be stopped. That is, the light storage device 20 can be shut down by the DC converter, disconnecting the connection between the DC power source 10 and the power grid 30, realizing safe off-grid. In this way, the light storage device 20 only needs to be provided with one switching device to realize off-grid, which can reduce the cost of the light storage device.

[0034] In some embodiments of the present application, the off-grid control state can include at least one of the following: grid-connected, grid-connected to off-grid, off-grid, off-grid to grid-connected, standby to off-grid, and standby to grid-connected. The optical storage device is in a standby state after starting up. In the standby state, the first switching device K21 is open. The optical storage device can receive an off-grid control signal and respond to the off-grid control signal to achieve the off-grid control state indicated by the off-grid control signal. For example, in the standby state, the optical storage device 20 needs to switch to grid-connected, and the first switching device K21 can be controlled to be closed.

[0035] In some embodiments of the present application, the mismatch includes: the switching state of the first switching device K21 is closed, and the off-grid control state includes any one of the following: grid-connected to off-grid, off-grid to grid-connected, standby to off-grid, and standby to grid-connected.

[0036] In an embodiment of the present application, the switching state of the first switching device K21 is closed, and the AC / DC converter 22 is connected to the power grid 30, so that the optical storage device 20 can be in grid-connected. If the AC / DC converter 22 is in a state of no work (including a shutdown state) at this time, even if the first switching device K21 is closed, it does not belong to grid-connected. When the off-grid control state is any one of grid-connected to off-grid, off-grid to grid-connected, standby to off-grid, and standby to grid-connected, the first switching device K21 needs to be able to achieve the state of being open.

[0037] For example, when the first switching device K21 is implemented as a control relay, in the case of a stuck fault of the control relay, the first switching device K21 will maintain a closed state, continuously connecting the AC / DC converter 22 and the power grid 30, and the optical storage device 20 will only be in grid-connected when the AC / DC converter 22 is in a running state. At this time, the digital signal processing module 232 can normally drive the AC / DC converter 22, thereby realizing normal power supply to the load. If the digital signal processing module 232 receives an off-grid control signal indicating that the optical storage device switches to off-grid, it can stop driving the AC / DC converter 22 to achieve off-grid.

[0038] In some embodiments of the present application, the mismatch includes: the switching state of the first switching device K21 is open, and the off-grid control state includes any one of the following: grid-connected, grid-connected to off-grid, off-grid to grid-connected, and standby to grid-connected.

[0039] In an embodiment of the present application, in an embodiment of the present application, the switching state of the first switching device K21 is open, and the AC / DC converter 22 is disconnected from the power grid 30, so that the optical storage device 20 can be in off-grid. At this time, grid-connected and other off-grid control states related to grid-connected, including grid-connected to off-grid, off-grid to grid-connected, and standby to off-grid, cannot be achieved through the first switching device K21.

[0040] Exemplarily, in the case that the first switching device K21 is implemented as a control relay and the control relay has a contact open fault, the first switching device K21 will maintain the open state, and the light storage device 20 will only be in off-grid. At this time, the digital signal processing module 232 can normally drive the AC / DC converter 22, so as to realize normal power supply to the load. If the digital signal processing module 232 receives a grid-connected control signal indicating that the light storage device switches to grid-connected, the driving of the AC / DC converter 22 can be stopped.

[0041] Based on Figure 2 , Figure 3 The structure of the light storage device is shown in FIG. 1. As shown in FIG. 1, the light storage device can further include a switching control circuit 233; the digital signal processing module 232 is further configured to control the switching control circuit 233 to be turned on or turned off according to the grid-connected control state indicated by the grid-connected control signal; when the switching control circuit 233 is turned on, the first switching device is closed; and when the switching control circuit 233 is turned off, the first switching device is opened. Figure 3

[0042] In the embodiment of the present application, the digital signal processing module 232 can control the switching control circuit 233 to be turned on or turned off, control the first switching device K21 to be closed by turning on the switching control circuit 233, or control the first switching device K21 to be opened by turning off the switching control circuit 233. In the case that the light storage device 20 is in grid-connected, and the grid-connected control signal indicates that the light storage device is off-grid, the digital signal processing module 232 can respond to the grid-connected control signal, control the switching control circuit 233 to be turned off, and make the first switching device K21 be opened. In the case that the light storage device 20 is in off-grid, and the grid-connected control signal indicates that the light storage device is grid-connected, the digital signal processing module 232 can respond to the grid-connected control signal, control the switching control circuit 233 to be turned on, and make the first switching device K21 be closed.

[0043] It can be understood that the digital signal processing module 232 can normally drive the AC / DC converter 22 to ensure normal power supply to the load in the case that the switching state matches the grid-connected control state, stop driving the AC / DC converter 22 in the case that the switching state does not match the grid-connected control state, so as to make the light storage device 20 be in a shutdown protection state, and send an alarm information to prompt a maintenance personnel to maintain the fault condition. In this way, the control functions are collected in the digital signal processing module 232, and the configuration of the light storage device 20 can be simplified.

[0044] ​In this embodiment, the switch control circuit 233 includes a coil, a battery, and a switching device connected in series. When the switching device is closed, the switch control circuit 233 is turned on, the battery supplies power, and current flows through the coil, causing the first switching device K21 to be attracted. When the switching device is turned off, the switch control circuit 233 is turned off, no current flows through the coil, and the first switching device K21 is turned off. Correspondingly, the digital signal processing module 232 can be implemented as a DSP, which controls the switching device in the switch control circuit 233 to turn on and off, thereby realizing the on and off state of the switch control circuit 233.

[0045] based on Figure 3 , Figure 4 The structure of a photoelectric storage device is shown, such as Figure 4 As shown, the digital signal processing module 232 includes two digital circuit processors, DSP1 and DSP2; the switch control circuit 233 includes two second switching devices K22 and K23 connected in series; when both second switching devices K22 and K23 are closed, the switch control circuit 233 is turned on; when either K22 or K23 is open, the switch control circuit 233 is turned off. Specifically, DSP1 controls K22 to close when the grid connection control signal indicates that the switch control circuit 233 is on; or, controls K22 to open when the grid connection control signal indicates that the switch control circuit 233 is off. DSP2 controls K23 to close when the grid connection control signal indicates that the switch control circuit 233 is on; or, controls K23 to open when the grid connection control signal indicates that the switch control circuit 233 is off.

[0046] In this embodiment, both DSP1 and DSP2 in the digital signal processing module 232 can receive the grid connection / disconnection control signal and control the switching control circuit 233 to turn on and off according to the grid connection / disconnection control state indicated by the signal. When the switching control circuit 233 needs to be on, DSP1 instructs K22 to close, and DSP2 instructs K23 to close simultaneously. With both K22 and K23 closed, the switching control circuit 233 is on, the battery P supplies power, and current flows through the coil LL. When the switching control circuit 233 needs to be off, DSP1 instructs K22 to open, and DSP2 instructs K23 to open simultaneously.

[0047] In this embodiment, when either K22 or K23 experiences a short circuit fault, the other can, under the control of the corresponding DSP, enable the switching control circuit 233 to be turned on and off, thereby controlling the switching state of the first switching device K21 and realizing the grid connection / disconnection control state of the optical storage device 20.

[0048] In the embodiment of the present application, when K22 or K23 has an open circuit fault, the switch control circuit 233 cannot be turned on, and the first switch device K21 cannot be closed.

[0049] In the embodiment of the present application, the DSP1 and the DSP2 can send an IO control signal to the corresponding second switch device. When the IO control signal is high, the second switch device is closed; when the IO control signal is low, the second switch device is opened. In the case that the IO control signal of any one of the DSP1 and the DSP2 remains high and cannot output low, the corresponding second switch device cannot be opened; the other DSP can control the corresponding second switch device to be turned on and off, so as to control the switch control circuit 233 to be turned on and off, thereby controlling the switching state of the first switch device K21 and realizing the grid-connected and off-grid control state of the optical storage device 20.

[0050] It can be understood that, by setting the redundant switch device for the switch control circuit 233 and the redundant DSP for the digital signal processing module 232, the combination of the DSP-second switch device and the corresponding redundant combination can reduce the risk of grid-connected and off-grid abnormality caused by the failure of one combination.

[0051] In some embodiments of the present application, the DSP1 and the DSP2 are further configured to stop sending a driving signal to the AC / DC converter 22 in the case that the grid-connected and off-grid control state does not match the first switching state; the driving signal is used to drive the AC / DC converter 22 to be in a running state; the AC / DC converter 22 is further configured to enter the running state in the case that the driving signal from any one of the DSPs is received.

[0052] In the embodiment of the present application, the DSP1 and the DSP2 can both send a driving signal to the AC / DC converter 22 based on the communication function to drive the AC / DC converter 22 to run. In the case that at least one DSP sends the driving signal to the AC / DC converter 22, the AC / DC converter 22 can be in the running state. Therefore, in the case that any one of the DSPs fails to send the driving signal to the AC / DC converter 22, the AC / DC converter 22 can still run normally under the action of the driving signal of the other DSP. In this way, the safety of the running of the AC / DC converter 22 can be improved.

[0053] In some embodiments of the present application, the DSP drives the AC / DC converter 22 and controls the corresponding second switch device through the communication function; the communication connection is established between the DSPs; any one of the two DSPs determines that the communication function of the other DSP is abnormal in the case that the other DSP's communication information is not received within a preset feedback time period; and the driving signal is stopped from being sent.

[0054] In the embodiment of the present application, the communication connection is established between the DSP1 and the DSP2, and the communication information can be fed back once every preset feedback time interval between the DSP1 and the DSP2. The preset feedback time interval can be set according to actual needs, and the embodiment of the present application does not limit it. Here, the communication information can include the detected on-grid control state and the first switch state, and can also include whether the control function and the communication function of the DSP itself are normal or not. For this, the embodiment of the present application does not limit it, and it can be set according to actual needs.

[0055] In the embodiment of the present application, in the case that any one of the DSPs does not receive the communication information of the other DSP within the preset feedback time interval, it is determined that the communication function of the other DSP is abnormal. When the communication function of the DSP is normal, the DSP can send the driving signal to the AC / DC converter 22 and send the IO control signal to the corresponding second switch device; when the communication function of the DSP is abnormal, the DSP cannot control the switch control circuit 233, which can cause abnormal on-grid and off-grid. At this time, the DSP with normal communication function can stop sending the driving signal to the AC / DC converter 22. Since the communication function of the other DSP is abnormal, the driving signal cannot be sent to the AC / DC converter 22, and the AC / DC converter 22 will not receive the driving signal, and then enters the shutdown state, realizing off-grid.

[0056] It can be understood that through the feedback of the communication information between the two DSPs, in the case that the communication function of one DSP is abnormal, the other DSP can learn it in time and control the light storage equipment to off-grid, improving the safety of the operation of the light storage equipment.

[0057] In some embodiments of the present application, one of the DSP1 and the DSP2 is a master DSP, and the other is a secondary DSP. The master DSP sends the driving signal to the AC / DC converter 22, and the secondary DSP does not send the driving signal to the AC / DC converter 22. In the case that the communication function of the secondary DSP is abnormal, the master DSP can stop sending the driving signal to the AC / DC converter 22. In this way, in the case that the communication function of any one of the DSPs is abnormal, the master DSP will not send the driving signal, so that the AC / DC converter 22 is shut down, realizing off-grid.

[0058] Based on the above embodiment, Table 1 shows the processing mode of the DSP when various fault conditions occur under different on-grid and off-grid control states. Among them,

[0059] The on-grid and off-grid control state includes: on-grid 1, on-grid to off-grid 2, off-grid 3, off-grid to on-grid 4, standby to off-grid 5, and standby to on-grid 6.

[0060] The fault conditions include: G1, the first switch device contact is stuck, that is, the first switch device is always closed. G2, the contact of a DSP-controlled second switch device is short-circuited (that is, always closed); the other DSP-controlled second switch device is normal. G3, the IO control signal of a DSP is always high, that is, the second switch device controlled by the DSP is always closed; the second switch device controlled by the other DSP is normal. G4, the contact of a DSP-controlled second switch device is open (that is, always open); the contact of the second switch device controlled by the other DSP is normal. G5, the DSP runs away, for example, DSP1 does not receive the communication information fed back by DSP2 within a preset feedback time period.

[0061] Table 1

[0062]

[0063] In Table 1, "N" indicates that the DSP sends a driving signal to the AC-DC converter 22 to normally drive the AC-DC converter 22.

[0064] In some embodiments, the digital signal processing module 232 can feed back the mismatching condition in a case where it is determined that the off-grid control state and the switching state of the first switch device K21 do not match, so that the user can learn about the occurrence of the mismatching condition in a timely manner, and then quickly find the fault condition, solve the fault, and restore the normal operation of the optical storage device 20.

[0065] Based on Figure 4 , Figure 5 As shown in FIG. 1, the optical storage device 20 can further include a switching state detection module 234 connected to the first switch device K21. Figure 5 The switching state detection module 234 is configured to detect the switching state of the first switch device K21 and feed back the switching state to the digital signal processing module 232.

[0066] In the embodiments of the present application, the switching state detection module 234 is connected to DSP1 and also connected to DSP2. In this way, DSP1 and DSP2 can both obtain the switching state fed back by the switching state detection module 234, and the switching states obtained by DSP1 and DSP2 are the same.

[0067] Based on Figure 5 , Figure 6 As shown in FIG. 1, the optical storage device 20 can further include a switching state detection module 234 connected to the first switch device K21. Figure 6 The switching state detection module 234 is configured to detect the switching state of the first switch device K21 and feed back the switching state to the digital signal processing module 232.

[0068] In the embodiment of the present application, when the direct current source 10 and the power grid 30 are turned on, the instantaneous conduction current may be too large to cause impact on the devices in the optical storage device, and further cause voltage fluctuation of the power grid 30 and the like. Therefore, the direct current slow start control circuit 24 is arranged in the direct current source 10 and the AC-DC converter 22, so that the direct current slow start is realized, the influence of the instantaneous current being too large is reduced, and the working safety of the optical storage device 20 is improved.

[0069] In some embodiments, the direct current slow start control circuit 24 can include a series resistance, and the instantaneous conduction current is reduced by the series resistance. In some embodiments, the direct current slow start control circuit 24 can use the voltage chopping control method to perform chopping control on the voltage during conduction. For the implementation of the direct current slow start control circuit 24, it can be set according to actual needs, and the embodiment of the present application is not limited.

[0070] Based on Figure 6 , Figure 7 The structure of an optical storage device is shown, as shown in Figure 7 The direct current slow start control circuit 24 can include a third switching device K24, a resistance R and a fourth switching device K25. The series circuit of the resistance R and the fourth switching device K25 is connected in parallel with the third switching device K24.

[0071] In the embodiment of the present application, at the initial stage of the direct current source 10 and the power grid 30 being turned on, the fourth switching device K25 can be first controlled to be closed, and the resistance R is connected in series in the circuit, so that the conduction current can be reduced, and the instantaneous conduction current being too large is avoided. After a preset conduction time period, the fourth switching device K25 is controlled to be opened and the third switching device K24 is controlled to be closed. The preset conduction time period can be set according to actual needs, and the embodiment of the present application is not limited. The direct current slow start is realized by the series resistance R, and the cost is low.

[0072] In some embodiments, the first switching device K21, the second switching devices K22 and K23, the third switching device K24 and the fourth switching device K25 are all mechanical switching devices.

[0073] It should be noted that the descriptions of the various embodiments above tend to emphasize the differences between them, while their similarities or commonalities can be referred to interchangeably. In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple modules or components can be combined, or integrated into another system, or some features can be ignored or not executed. Furthermore, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces; the indirect coupling or communication connection between devices or modules can be electrical, mechanical, or other forms.

[0074] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and scope of this application are included within the scope of protection of this application.

Claims

1. A light storage device, characterized by, The application relates to a photovoltaic storage device, which comprises the following components: an AC-DC converter and an on-grid / off-grid conversion device; a first end of the AC-DC converter is connected with a DC power source, and a second end of the AC-DC converter is connected with a power grid through the on-grid / off-grid conversion device; the AC-DC converter is used for performing AC-DC conversion between the DC power source and the power grid in a running state; the on-grid / off-grid conversion device comprises: a first switch device, which is used for conducting the connection between the DC power source and the power grid when the first switch device is closed, or disconnecting the connection when the first switch device is opened; a digital signal processing module, which is used for acquiring an on-grid / off-grid control state of the photovoltaic storage device and a switch state of the first switch device, and stopping driving the AC-DC converter in the case that the on-grid / off-grid control state does not match the switch state of the first switch device; the AC-DC converter enters a shutdown state and disconnects the connection; the on-grid / off-grid conversion device further comprises a switch control circuit; the digital signal processing module is further used for controlling the switch control circuit to be conducted or disconnected according to an on-grid / off-grid control state indicated by an on-grid / off-grid control signal; the first switch device is closed when the switch control circuit is conducted; and the first switch device is opened when the switch control circuit is disconnected; the switch control circuit comprises a coil, a battery and a switch device which are connected in series; the switch control circuit is conducted, the battery supplies power, and current is passed through the coil to attract the first switch device when the switch device is closed; and the switch control circuit is disconnected, and no current is passed through the coil to disconnect the first switch device when the switch device is opened; the digital signal processing module comprises two digital circuit processors (DSPs); the switch control circuit comprises two second switch devices which are connected in series; the switch control circuit is conducted when both the second switch devices are closed; and the switch control circuit is disconnected when any one of the second switch devices is opened; the DSP is used for controlling a corresponding second switch device to be closed in the case that the on-grid / off-grid control signal indicates that the switch control circuit is conducted, or controlling the corresponding second switch device to be opened in the case that the on-grid / off-grid control signal indicates that the switch control circuit is disconnected.

2. The optical storage device of claim 1, wherein The on-grid / off-grid control state comprises at least one of the following states: on-grid, on-grid-to-off-grid, off-grid, off-grid-to-on-grid, standby-to-off-grid and standby-to-on-grid.

3. The optical storage device of claim 2, wherein, The mismatch comprises: the switch state of the first switch device is closed, and the on-grid / off-grid control state comprises any one of the following states: on-grid-to-off-grid, off-grid-to-on-grid, standby-to-off-grid and standby-to-on-grid.

4. The optical storage device of claim 2, wherein, The mismatch comprises: the switch state of the first switch device is opened, and the on-grid / off-grid control state comprises any one of the following states: on-grid, on-grid-to-off-grid, off-grid-to-on-grid and standby-to-on-grid.

5. The photovoltaic storage device according to claim 1, wherein the DSP is further used for stopping sending a driving signal to the AC-DC converter in the case that the on-grid / off-grid control state does not match the switch state of the first switch device; the driving signal is used for driving the AC-DC converter to be in the running state. The AC / DC converter is also configured to enter the shutdown state when the driving signal is not received.

6. The optical storage device of claim 5, wherein, The DSP drives the AC / DC converter and controls the corresponding second switching device through a communication function, and communication connections are established between the DSPs. Any one of the two DSPs is also configured to determine that the other DSP has a communication function failure when the other DSP does not send communication information within a preset feedback time period, and stop sending the driving signal.

7. The optical storage device of any of claims 1-4, wherein, The on-off grid conversion device further comprises: A switching state detection module is configured to detect a switching state of the first switching device and feed back the switching state to the digital signal processing module.

8. The optical storage device of any of claims 1-4, wherein, The optical storage device further comprises a DC slow start control circuit connected in series between the DC source and the AC / DC converter. The DC slow start control circuit is configured to control conduction between the DC source and the AC / DC converter to achieve DC slow start.

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