A PID effect suppression and repair system for a photovoltaic storage hybrid system

Abstract

The present application discloses a PID effect suppression and repair system for a photovoltaic-storage hybrid system, comprising a PID suppression module and a plurality of PID suppression and repair modules; the PID suppression module is arranged at a neutral point shared by the AC side of the photovoltaic-storage hybrid system; each PID suppression and repair module is respectively arranged on the DC side of each photovoltaic-storage inverter; when at least one photovoltaic-storage inverter is connected to the grid, the PID suppression module operates normally, while the PID suppression and repair module corresponding to the photovoltaic inverter connected to the grid stops working; for the photovoltaic-storage inverter that is off-grid, the corresponding PID suppression and repair module suppresses or repairs PID according to the working status of the photovoltaic module and the energy storage battery. The beneficial effects of the present application are as follows: according to the working status of the photovoltaic-storage hybrid system, the coordinated operation of the DC-side PID suppression and repair module and the AC-side PID suppression module is controlled to achieve PID effect suppression or repair of the photovoltaic module when the photovoltaic-storage inverter is on-grid or off-grid in the system.

Description

Technical Field

[0001] The present application relates to the field of new energy power generation technology, and in particular to a PID effect suppression and repair system for a photovoltaic and storage hybrid system. Background Art

[0002] The PID effect refers to the photovoltaic potential-induced degradation (PID) effect in photovoltaic systems. This occurs when a battery module is exposed to high voltage for a long period of time, causing leakage current between the glass and the encapsulation material. This causes a large amount of charge to accumulate on the cell surface, degrading the passivation effect. Severe PID can cause the power of a single battery module to decay by more than 50%, affecting the power output of the entire battery string.

[0003] Existing solutions to the PID effect in photovoltaic systems include:

[0004] (1) Directly ground the negative pole of the inverter busbar or connect it to grounding resistor; this solution is simple, low-cost and effective.

[0005] (2) Adopt the AC side virtual neutral point raising scheme, and raise the AC side virtual neutral point potential to ground by adding an external DC source, so as to raise the busbar center point potential to ground, thereby indirectly raising the component negative pole potential to ground.

[0006] (3) PID repair is achieved by applying positive pressure between the negative pole of the photovoltaic array and the ground.

[0007] The above technical solutions have the following defects when used: For solution (1), the grounding of the negative pole of the inverter bus causes the positive pole of the component to have a high voltage relative to the ground potential. If a grounding fault occurs in the positive pole of the component, it will cause a short circuit of the solar panel, and if the operation and maintenance personnel touch the positive pole, there will be a risk of electric shock or even fire. For solution (2), when the inverter stops working at night, the relay inside the inverter is disconnected, and the rise of the virtual neutral point on the AC side cannot change the midpoint potential of the DC input bus, so the PID compensation and repair of the component cannot be achieved. For solution (3), a forward bias voltage or positive voltage is usually applied to promote the migration of ions (such as sodium ions) to the cell, but this process can only work when the inverter stops working. At the same time, the above solutions are all for photovoltaic systems. When applied to photovoltaic storage hybrid systems, it will not be possible to suppress the PID effect. Summary of the Invention

[0008] One of the objectives of the present application is to provide a PID effect suppression and repair system for a photovoltaic storage hybrid system that can solve at least one of the defects in the above-mentioned background technology.

[0009] In order to achieve at least one of the above-mentioned purposes, the technical solution adopted in the present application is: a PID effect suppression and repair system for a photovoltaic and storage hybrid system, comprising a PID suppression module and multiple PID suppression and repair modules; the PID suppression module is arranged at the neutral point shared by the AC side of the photovoltaic and storage hybrid system; each of the PID suppression and repair modules is respectively arranged on the DC side of each photovoltaic and storage inverter corresponding to the photovoltaic and storage hybrid system; when at least one photovoltaic and storage inverter is connected to the grid, the PID suppression module performs normal operation, and at the same time, the PID suppression and repair module corresponding to the photovoltaic inverter connected to the grid stops working; for the photovoltaic and storage inverter that is off-grid, the corresponding PID suppression and repair module performs PID suppression or repair according to the working status of the photovoltaic components and the energy storage battery.

[0010] Preferably, for an off-grid photovoltaic inverter, if any one of the photovoltaic components and the energy storage battery is in working condition, the corresponding PID suppression and repair module outputs voltage compensation so that the negative pole voltage of the photovoltaic component is raised to zero or close to zero; if both the photovoltaic component and the energy storage battery stop working, the corresponding PID suppression and repair unit applies a high voltage between the negative pole of the photovoltaic string and the ground.

[0011] Preferably, the PID suppression module includes a PID suppression unit and a first switch, and the PID suppression and repair module includes a PID suppression and repair unit and a second switch; the PID effect suppression and repair system of the photovoltaic-storage hybrid system also includes a communication module, which is suitable for collecting working data of the photovoltaic-storage hybrid system and controlling the first switch and the second switch to be turned on or off according to the collected data, thereby connecting the PID suppression unit and / or the PID suppression and repair unit to the photovoltaic-storage hybrid system.

[0012] Preferably, the communication module includes a master controller and multiple slave controllers that communicate with each other; the master controller is suitable for collecting AC side data of the photovoltaic-storage hybrid system, and each slave controller is suitable for collecting corresponding working data of each photovoltaic-storage inverter and feeding it back to the master controller; the master controller is suitable for judging the networking status of the photovoltaic-storage hybrid system based on the acquired data, and then sending a first control signal to the first switch, and / or sending a second control signal to each slave controller to control each second switch, and the slave controller is suitable for forwarding the received second control signal to the corresponding second switch.

[0013] Preferably, the communication module includes a master controller and multiple slave controllers that communicate with each other; the master controller is suitable for collecting AC side data of the photovoltaic-storage hybrid system, and each slave controller is suitable for collecting the working data of each photovoltaic-storage inverter and feeding it back to the master controller; the master controller is suitable for judging the networking status of the photovoltaic-storage hybrid system based on the acquired data, and then directly sending corresponding control signals to the first switch and / or the second switch.

[0014] Preferably, when all the photovoltaic and storage inverters of the photovoltaic and storage hybrid system are in the grid-connected state, the specific control process of the communication module is as follows: the main controller polls all the photovoltaic and storage inverters through the slave controller to obtain the voltage data of the DC and AC sides of the photovoltaic and storage hybrid system, and calculates the rise amplitude of the midpoint potential on the AC side, and then sends a PID suppression instruction to the PID suppression module.

[0015] Preferably, when some photovoltaic and storage inverters of the photovoltaic and storage hybrid system are in a grid-connected state, the specific control process of the communication module is as follows: the main controller polls all photovoltaic and storage inverters through the slave controller to obtain the voltage data of the DC side and the AC side of the photovoltaic and storage hybrid system, and calculates the AC side midpoint potential rise amplitude according to the potential distribution of the grid-connected photovoltaic and storage inverters, and then sends a PID suppression instruction to the PID suppression module to close the first switch corresponding to the PID suppression module; at the same time, the main controller controls the second switch of the PID suppression and repair module corresponding to the off-grid photovoltaic and storage inverter to close, and judges the working status according to the obtained working data of the photovoltaic components and energy storage batteries corresponding to the off-grid photovoltaic and storage inverter; if any one of the photovoltaic components and energy storage batteries corresponding to the off-grid photovoltaic and storage inverter is in a working state, sends a PID suppression instruction to the corresponding PID suppression and repair module; if the photovoltaic components and energy storage batteries corresponding to the off-grid photovoltaic and storage inverter both stop working, sends a PID repair instruction to the corresponding PID suppression and repair module.

[0016] Preferably, when all photovoltaic and storage inverters of the photovoltaic and storage hybrid system are in an off-grid state, the specific control process of the communication module is as follows: the master controller polls all photovoltaic and storage inverters through the slave controller, and controls the second switches of all the PID suppression and repair modules to be closed; at the same time, the working status is judged according to the working data of the photovoltaic components and energy storage batteries corresponding to all the photovoltaic and storage inverters; if any one of the photovoltaic components and energy storage batteries corresponding to the photovoltaic and storage inverter is in a working state, a PID suppression instruction is sent to the corresponding PID suppression and repair module; if the photovoltaic components and energy storage batteries corresponding to the photovoltaic and storage inverter both stop working, a PID repair instruction is sent to the corresponding PID suppression and repair module.

[0017] Preferably, if the negative end of the photovoltaic module of each photovoltaic storage inverter is electrically connected to the DC side negative bus, the PID suppression and repair module is set at any position of the DC side bus midpoint of the photovoltaic storage inverter, the DC side negative bus and the negative end of the photovoltaic module.

[0018] Preferably, if there is no electrical connection between the negative terminal of the photovoltaic module of each photovoltaic storage inverter and the negative busbar on the DC side, the PID suppression and repair module is arranged at the negative terminal of the photovoltaic module.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] According to the working status of the photovoltaic and storage hybrid system, the coordinated work of the DC side PID suppression and repair module and the AC side PID suppression module is controlled to suppress or repair the PID effect of the photovoltaic modules when the photovoltaic and storage inverters are connected to or off the grid in the system, so as to solve the problem of PID effect accumulation of photovoltaic modules in the photovoltaic and storage hybrid system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall architecture of this application.

[0022] Figure 2 This is a schematic diagram of the specific structures of the PID suppression and repair unit and the PID suppression unit in this application.

[0023] Figure 3 This is a schematic diagram of the architecture of one example of the communication module in this application.

[0024] Figure 4 This is a schematic diagram of the architecture of another example of the communication module in this application.

[0025] Figure 5 This is a schematic diagram of the working process of the photovoltaic storage hybrid system of this application in a fully grid-connected state.

[0026] Figure 6 This is a schematic diagram of the overall architecture of this application in a fully grid-connected state.

[0027] Figure 7 This is a timing diagram of the present application in a fully grid-connected state.

[0028] Figure 8 This is a schematic diagram of the working process of the photovoltaic storage hybrid system of this application in a hybrid state.

[0029] Figure 9 This is a schematic diagram of the overall architecture of this application in a hybrid state.

[0030] Figure 10 This is a timing diagram of the present application in a mixed state.

[0031] Figure 11This is a schematic diagram of the workflow of the photovoltaic storage hybrid system of this application in a fully off-grid state.

[0032] Figure 12 This is a schematic diagram of the overall architecture of this application in a completely off-grid state.

[0033] Figure 13 This is a timing diagram of the present application in a completely off-grid state.

[0034] In the figure: PID suppression and repair unit 100, PID suppression unit 200, main controller 310, slave controller 320. DETAILED DESCRIPTION

[0035] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, in the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like are intended to mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0036] In the description of this application, it should be noted that for directional words, such as the terms "center", "horizontal", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and so on, indicating the orientation and position relationship are based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of this application.

[0037] It should be noted that the terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0038] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0039] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0040] The terms "comprises" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units expressly listed, but may include other steps or units not expressly listed or inherent to such process, method, product or apparatus.

[0041] One of the preferred embodiments of this application is as follows: Figure 1 As shown, a PID effect suppression and repair system for a photovoltaic and energy storage hybrid system includes a PID suppression module and multiple PID suppression and repair modules. The PID suppression module is set at the neutral point shared by the AC side of the photovoltaic and energy storage hybrid system; each PID suppression and repair module is respectively set on the DC side of each photovoltaic and energy storage inverter corresponding to the photovoltaic and energy storage hybrid system. When at least one photovoltaic and energy storage inverter is connected to the grid, the PID suppression module operates normally, and at the same time, the PID suppression and repair module corresponding to the photovoltaic inverter connected to the grid stops working. For the photovoltaic and energy storage inverter that is off-grid, the corresponding PID suppression and repair module performs PID suppression or repair according to the working status of the photovoltaic components and energy storage batteries.

[0042] It should be noted that the specific architecture of the photovoltaic storage hybrid system is well known to those skilled in the art. For ease of understanding, the specific architecture of the photovoltaic storage hybrid system will be briefly described below. Figure 1As shown in the figure, the photovoltaic-storage hybrid architecture includes multiple photovoltaic-storage inverters, and the AC output of each photovoltaic-storage inverter is connected to the same three-phase AC grid. The AC output end of each photovoltaic-storage inverter has its own neutral point, but these neutral points are physically connected together after passing through the grid-connected relay switch to form a common neutral point, that is, all photovoltaic-storage inverters share a common neutral point.

[0043] Each PV-storage inverter has the same structure, consisting of a PV string, a storage battery, a DC / DC unit, a bidirectional DC / DC unit, and a DC / AC unit. The branch formed by the series connection of the PV string and the DC / DC unit, and the branch formed by the series connection of the energy storage battery and the bidirectional DC / DC unit, are connected in parallel to the AC side of the DC / AC unit. Each PV-storage inverter is connected in parallel to the three-phase AC grid via the AC side of the DC / AC unit. The AC side of the DC / AC unit of each PV-storage inverter is also connected to the load, allowing power to be supplied to the load via the PV string, the storage battery, or even the AC grid. Assuming there are N PV-storage inverters, each PV-storage inverter can be labeled PV-storage inverter #1 through #N.

[0044] It is important to note that when the solution for suppressing the PID effect of the photovoltaic system in the background technology is applied to the above-mentioned photovoltaic-storage hybrid system; if all photovoltaic-storage inverters in the photovoltaic-storage hybrid system are in a grid-connected state, the AC-side PID suppression module can be used to suppress the PID effect; if there is an off-grid photovoltaic-storage inverter in the photovoltaic-storage hybrid system, the AC-side PID suppression module alone cannot suppress the PID effect of the off-grid photovoltaic-storage inverter. Specifically, when the photovoltaic-storage inverter is off-grid, the photovoltaic module has no energy output, but the energy storage battery can still provide energy to the photovoltaic-storage inverter. At this time, the negative pole of the photovoltaic module continues to have a negative voltage relative to the ground; since the PID suppression module on the AC side in the off-grid state cannot directly suppress the PID of the photovoltaic module, the PID effect of the photovoltaic module will continue to accumulate.

[0045] In the technical solution of the present application, a PID suppression module is connected to the common neutral point position on the AC side of the photovoltaic-storage hybrid system, and a PID suppression and repair module is connected to the DC side of each photovoltaic-storage inverter. Thus, when there is at least one photovoltaic-storage inverter in the photovoltaic-storage hybrid system connected to the grid, the PID suppression module can be used to suppress the PID effect of the grid-connected photovoltaic-storage inverter. For off-grid photovoltaic-storage inverters, the PID suppression and repair module can be used to suppress or repair the PID effect in combination with the working status of photovoltaic modules and energy storage batteries. Compared with the traditional method, the present application controls the coordinated operation of the DC-side PID suppression and repair module and the AC-side PID suppression module according to the working status of the photovoltaic-storage hybrid system, so as to suppress or repair the PID effect of the photovoltaic modules when the photovoltaic-storage inverter is connected to or off-grid in the system, so as to solve the problem of PID effect accumulation of photovoltaic modules in the photovoltaic-storage hybrid system.

[0046] In this embodiment, for an off-grid solar-storage inverter, if either the PV panel or the energy storage battery is in operation, the corresponding PID suppression and repair module outputs voltage compensation to raise the voltage at the negative electrode of the PV panel to zero or near zero, thereby suppressing the PID effect of the PV panel. If both the PV panel and the energy storage battery are inoperative, the corresponding PID suppression and repair unit applies a high voltage between the negative electrode of the PV string and ground, thereby repairing the PID effect of the PV panel.

[0047] It is understandable that when either the photovoltaic module or the energy storage battery is in working condition, for example, the energy storage battery is in working condition and the photovoltaic module stops working; at this time, the energy storage battery will output energy to keep the photovoltaic inverter in working condition, which makes the negative pole of the photovoltaic module to the ground voltage continue to be negative, which will lead to the accumulation of PID effect in the photovoltaic module. Since PID repair can only be performed when the photovoltaic inverter is shut down, the output voltage compensation of the PID suppression and repair module is used to raise the negative pole of the photovoltaic module to the ground voltage. When both the photovoltaic module and the energy storage battery are shut down, the photovoltaic inverter is in a shutdown state, that is, the photovoltaic module no longer accumulates PID effects. In this state, the PID suppression and repair module can be used to perform PID repair on the photovoltaic module, thereby restoring the performance of the photovoltaic module.

[0048] In this embodiment, Figure 1 As shown, the PID suppression module includes a PID suppression unit 200 and a first switch S PID-AC PID suppression unit 200 is switched on by the first switch S PID-AC Connected between the neutral point shared by the AC side of the photovoltaic storage hybrid system and the ground. When there is a photovoltaic storage inverter connected to the grid in the photovoltaic storage hybrid system, the first switch S PID-AC The PID suppression unit 200 is connected by closing, thereby achieving PID suppression of the grid-connected photovoltaic storage inverter.

[0049] The PID suppression and repair module includes a PID suppression and repair unit 100 and a second switch S PID PID suppression and repair unit 100 is connected to the PID control circuit 101 by the second switch S PID Connected between the DC side of the photovoltaic storage inverter and the ground; since the number of PID suppression and repair modules corresponds to the number of photovoltaic storage inverters, the second switch S corresponding to each PID suppression and repair module PID Can be marked as S PID1 To S PIDN When there is an off-grid solar-storage inverter in the solar-storage hybrid system, the second switch S PIDThe PID suppression unit 200 is connected to the off-grid photovoltaic storage inverter by closing; then PID suppression or PID repair can be performed according to the working status of the photovoltaic components and energy storage batteries in the off-grid photovoltaic storage inverter.

[0050] It is understandable that both the PID suppression unit and the PID suppression and repair unit adopt a PID effect device. There are many specific structures of the PID effect device. For easy understanding, a detailed description will be given below through several specific examples.

[0051] Specifically, example 1: Figure 2 As shown in (1), the PID effect device includes a fuse.

[0052] Example 2: To ensure the stable operation of the fuse, Figure 2 As shown in (2), the PID effect device includes a fuse and a fixed resistor connected in series.

[0053] Example 3: If Figure 2 As shown in (3), the PID effect device includes a switch and a diode connected in series. The diode is connected and disconnected by controlling the closing and opening of the switch, thereby suppressing the PID effect.

[0054] Example 4: Figure 2 As shown in (4), the PID effect device includes a switch and a power supply connected in series. The power supply is connected and disconnected by controlling the closing and closing of the switch, and the PID effect is suppressed or repaired based on the output voltage of the power supply.

[0055] Example 5: To avoid reverse current of power supply, Figure 2 As shown in (5), the PID effect device includes a switch, a diode and a power supply connected in series.

[0056] It should be known that for the PID suppression and repair unit on the DC side, the above-mentioned Example 4 or Example 5 can be directly used to suppress or repair the PID effect; of course, it can also be used together with any one of Examples 1 to 3 and Example 4 or Example 5. When Example 4 or Example 5 is applied to the PID suppression and repair unit, its power supply can be an independent voltage source, or it can be obtained by taking power from the power grid and converting it through an AC-DC circuit. For the PID suppression unit on the AC side, since it needs to perform voltage boosting to achieve the suppression of the PID effect, only the above-mentioned Example 4 or Example 5 can be selected to suppress the PID effect; accordingly, its power supply can be an independent power supply, or it can be obtained by taking power from the power grid.

[0057] In this embodiment, the specific installation location of the PID suppression and repair module mainly depends on the connection relationship between the photovoltaic module and the DC bus. Figure 1As shown, if in the photovoltaic storage inverter, the negative end of the photovoltaic module is electrically connected to the negative bus on the DC side, then if the PID suppression and repair module corresponding to each photovoltaic storage inverter can be set at the midpoint of the DC side bus of the photovoltaic storage inverter, the DC side negative bus and any position of the negative end of the photovoltaic module. If the negative end of the photovoltaic module of each photovoltaic storage inverter is not electrically connected to the negative bus on the DC side, then the PID suppression and repair module can only be set at the negative end of the photovoltaic module. For ease of understanding, this application will take the example of the photovoltaic module being electrically connected to the negative bus on the DC side, and the PID suppression and repair module being connected to the negative bus on the DC side as an example to describe the subsequent content.

[0058] In this embodiment, the operation of the PID suppression module and the PID suppression and repair module can be controlled by the communication module. The communication module can collect the working data of the photovoltaic storage hybrid system and control the first switch S according to the collected data. PID-AC and the second switch S PID The PID suppression unit 200 and / or the PID suppression and repair unit 100 are connected to the photovoltaic storage hybrid system to suppress or repair the PID effect. There are many specific structures for the communication module that implements communication control. For ease of understanding, the following will be described in detail using a specific structure.

[0059] Specifically, such as Figure 3 As shown, the communication module includes a master controller 310 and N slave controllers 320 corresponding to the number of photovoltaic and energy storage inverters. The master controller 310 can collect the AC side data of the photovoltaic and energy storage hybrid system, and each slave controller 320 can collect the working data of each photovoltaic and energy storage inverter and feed it back to the master controller 310. The master controller 310 can determine the network status of the photovoltaic and energy storage hybrid system based on the acquired data, and then send a signal to the first switch S PID-AC and / or the second switch S PID Send corresponding control signals.

[0060] It is understood that the master controller 310 and the slave controller 320 are connected via a communication bus. There are many types of communication buses, such as a LAN bus and an RS485 bus. In this embodiment, the RS485 bus is preferably used. PID-AC and the second switch S PID There are two main control methods; the first one is Figure 3 As shown, the main controller 310 can directly switch S PID-AC Send the first control signal, and the main controller 310 can be used to control the second switch S PID The second control signal is sent to the slave controller 320 via the communication bus, and the slave controller 320 can forward the received second control signal to the corresponding second switch SPID The second type is Figure 4 As shown, the main controller 310 can directly switch S PID-AC and the second switch S PID The corresponding first control signal and second control signal are respectively sent. Both of the above-mentioned two control modes can meet the needs of this application, and those skilled in the art can make their own choices based on actual needs. In order to facilitate the description of the subsequent content, this embodiment preferably adopts the above-mentioned first control mode.

[0061] It should be noted that main controller 310, as the master node of the RS485 bus, is responsible for collecting and receiving various data, including the AC midpoint potential of the hybrid solar-storage system, the negative terminal-to-ground voltage of the photovoltaic module (PV), the PV output voltage, and the operating status of the energy storage battery. Based on this received data, main controller 310 determines the operating status of all solar-storage inverters, outputs control signals to the corresponding PID suppression module and PID suppression and repair module, and calculates the corresponding control parameters.

[0062] The slave controllers 320 act as slave nodes on the RS485 bus. Each slave controller 320 shares collected data with the master controller 310 via the RS485 bus, including the negative terminal voltage to ground of the photovoltaic module (PV), the output voltage of the PV module, the operating status of the energy storage battery, and the grid-connected and off-grid status of the photovoltaic storage inverter. The slave controllers 320 receive control commands from the master controller 310 and feed them back to the PID suppression and repair module, simultaneously calculating the control parameters for the PID suppression and repair module.

[0063] For ease of understanding, the specific process of the communication module controlling the PID suppression module and the PID suppression and repair module will be described in detail below in combination with the working status of the solar-storage inverter.

[0064] like Figure 5 As shown, when all the photovoltaic storage inverters of the photovoltaic storage hybrid system are in the grid-connected state, the specific control process of the communication module is as follows: the main controller 310 polls all the photovoltaic storage inverters from the controller 320 to obtain the voltage data of the DC side and AC side of the photovoltaic storage hybrid system. Among them, the DC side voltage data includes the output voltage of the photovoltaic module and the negative pole to ground voltage data, and the AC side voltage data mainly includes the AC side midpoint potential. Then the main controller 310 calculates the AC side midpoint potential rise amplitude based on the obtained voltage data, and then sends the PID suppression instruction as a control signal to the PID suppression module, then the first switch S corresponding to the PID suppression module PID-AC The PID suppression unit 200 performs voltage regulation and feeds back the result of the regulation.

[0065] It should be noted that in the control process of the communication module based on all the photovoltaic storage inverters being in the grid-connected state, Figure 6 As shown, the second switch S corresponding to all PID suppression and repair modules PID1 To S PIDN are all in the disconnected state. For ease of understanding, Figure 7 The timing diagram shown describes the control process of the communication module. During the time period from t1 to t2, each slave controller 320 transmits the collected data to the master controller 310 via the RS485 bus. The master controller 310 replies to the slave controller 320 within the set time at time t2 to confirm receipt of the data. Then, based on the received data, the master controller 310 calculates the voltage rise amplitude and generates and issues the control signal during the time period from t3 to t4. Finally, the PID suppression module on the AC side switches the corresponding first switch S to the 0 state according to the received high-level control signal at time t4. PID-AC It is closed, thereby suppressing the PID effect of the photovoltaic components of all photovoltaic storage inverters by raising the neutral point voltage on the AC side.

[0066] like Figure 8 As shown, when some of the photovoltaic and energy storage hybrid system's photovoltaic and energy storage inverters are in the grid-connected state, the specific control process of the communication module is as follows: the main controller 310 polls all photovoltaic and energy storage inverters from the controller 320 to obtain the voltage data of the DC and AC sides of the photovoltaic and energy storage hybrid system; wherein, the DC side voltage data includes data such as the output voltage of the photovoltaic module and the negative pole-to-ground voltage, and the AC side voltage data mainly includes the AC side midpoint potential. Then, the main controller 310 calculates the AC side midpoint potential rise amplitude based on the potential distribution of the grid-connected photovoltaic and energy storage inverters, and then sends a PID suppression instruction to the PID suppression module, so that the first switch S corresponding to the PID suppression module PID-AC The PID suppression unit 200 performs voltage regulation and feeds back the result of the regulation.

[0067] At the same time, the main controller 310 controls the second switch S of the PID suppression and repair module corresponding to the off-grid solar storage inverter PIDThe system is closed and the working status is determined based on the working data of the photovoltaic modules and energy storage batteries corresponding to the off-grid photovoltaic inverter. If any of the photovoltaic modules and energy storage batteries corresponding to the off-grid photovoltaic inverter are in working status, a PID suppression instruction is sent to the corresponding PID suppression and repair module, so that the PID suppression and repair unit raises the voltage of the negative pole of the photovoltaic module to 0 or close to 0, thereby suppressing the PID effect of the photovoltaic module. If both the photovoltaic modules and energy storage batteries corresponding to the off-grid photovoltaic inverter stop working, a PID repair instruction is sent to the corresponding PID suppression and repair module, so that the PID suppression and repair unit applies a high voltage to the negative terminal of the photovoltaic module, thereby repairing the accumulated PID effect of the photovoltaic module.

[0068] It should be noted that in the control process of the communication module based on the partial photovoltaic storage inverter being in the grid-connected state, such as Figure 9 As shown, the second switch S of the PID suppression and repair module corresponding to the off-grid solar storage inverter PID Close the second switch S of the PID suppression and repair module corresponding to the other grid-connected photovoltaic storage inverters. PID For example, if the 1st to mth photovoltaic storage inverters are operated off-grid, the PID suppression and repair units 100 on the DC side of the 1st to mth photovoltaic storage inverters are enabled; the PID suppression and repair units 100 on the DC side of the m+1st to Nth photovoltaic storage inverters that are continuously connected to the grid remain shut down. The PID suppression module on the AC side is activated by the first switch S PID-AC The closure of the switch can continuously suppress the PID effect.

[0069] For ease of understanding, we can Figure 10 The timing diagram shown in FIG1 describes the control process of the communication module. In the time period from t1 to t4, the working process of the master controller 310 and the slave controller 320 is basically the same as the above content, the difference is that the control signal generated by the master controller 310 controls the first switch S PID-AC and part of the second switch S PID Finally, the PID suppression module on the AC side switches the corresponding first switch S to ON at time t4 according to the received high-level first control signal. PID-AC At the same time, the PID suppression and repair module on the DC side of the off-grid photovoltaic storage inverter switches the corresponding second switch S to the PID control module according to the received high-level second control signal at time t4. PID1 To S PIDm Close.

[0070] like Figure 11As shown in the figure, when all the photovoltaic storage inverters of the photovoltaic storage hybrid system are in the off-grid state, the specific control process of the communication module is as follows: the main controller 310 polls all photovoltaic storage inverters through the slave controller 320 and controls the second switch S of all PID suppression and repair modules. PID Close; at the same time, determine the working status based on the working data of the photovoltaic modules and energy storage batteries corresponding to all photovoltaic storage inverters, and calculate the DC side voltage increase amplitude. If any of the photovoltaic modules and energy storage batteries corresponding to the photovoltaic storage inverter is in working state, send a PID suppression instruction to the corresponding PID suppression and repair module, so that the PID suppression and repair unit will raise the voltage of the negative pole of the photovoltaic module to 0 or close to 0, thereby suppressing the PID effect of the photovoltaic module. If both the photovoltaic modules and energy storage batteries corresponding to the photovoltaic storage inverter stop working, send a PID repair instruction to the corresponding PID suppression and repair module, so that the PID suppression and repair unit will apply a high voltage to the negative terminal of the photovoltaic module, thereby repairing the accumulated PID effect of the photovoltaic module.

[0071] It should be noted that in the control process of the communication module based on all the photovoltaic storage inverters being in the off-grid state, Figure 12 As shown, the second switch S corresponding to all PID suppression and repair modules PID1 To S PIDN Both are in the closed state, and the first switch S corresponding to the PID suppression module PID-AC In disconnected state. For ease of understanding, you can Figure 13 The timing diagram shown in FIG1 describes the control process of the communication module. During the time period from t1 to t4, the operation process of the master controller 310 and the slave controller 320 is basically the same as the above content, the difference is that the control signal generated by the master controller 310 only controls the second switch S PID Finally, all the PID suppression and repair modules turn on the corresponding second switch S according to the received high-level control signal at time t4. PID Close the circuit to suppress or repair PID according to the working status of the photovoltaic components and energy storage batteries corresponding to each photovoltaic inverter.

[0072] The above describes the basic principles, main features, and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-described embodiments. The above-described embodiments and the specification merely illustrate the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. These changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A PID effect suppression and repair system for a photovoltaic storage hybrid system, characterized in that: include: PID suppression module; The PID suppression module is arranged at the neutral point shared by the AC side of the photovoltaic and energy storage hybrid system; as well as Multiple PID suppression and repair modules; Each of the PID suppression and repair modules is respectively arranged on the DC side of each photovoltaic storage inverter corresponding to the photovoltaic storage hybrid system; When at least one photovoltaic storage inverter is connected to the grid, the PID suppression module operates normally, and the PID suppression and repair module corresponding to the photovoltaic inverter connected to the grid stops working; For off-grid photovoltaic inverters, the corresponding PID suppression and repair module performs PID suppression or repair according to the working status of photovoltaic modules and energy storage batteries; For an off-grid photovoltaic inverter, if any one of the photovoltaic module and the energy storage battery is in working condition, the corresponding PID suppression and repair module outputs voltage compensation so that the negative electrode voltage of the photovoltaic module is raised to zero or close to zero; If both the photovoltaic components and the energy storage battery stop working, the corresponding PID suppression and repair unit applies a high voltage between the negative pole of the photovoltaic string and the ground.

2. The PID effect suppression and repair system of the photovoltaic storage hybrid system according to claim 1, characterized in that: The PID suppression module includes a PID suppression unit and a first switch, and the PID suppression and repair module includes a PID suppression and repair unit and a second switch; The PID effect suppression and repair system of the photovoltaic-storage hybrid system also includes a communication module, which is suitable for collecting working data of the photovoltaic-storage hybrid system and controlling the first switch and the second switch to be turned on or off according to the collected data, thereby connecting the PID suppression unit and / or the PID suppression and repair unit to the photovoltaic-storage hybrid system.

3. The PID effect suppression and repair system of the photovoltaic storage hybrid system according to claim 2, characterized in that: The communication module includes a master controller and a plurality of slave controllers that communicate with each other; The master controller is adapted to collect AC side data of the photovoltaic-storage hybrid system, and each slave controller is adapted to correspondingly collect operating data of each photovoltaic-storage inverter and feed it back to the master controller; The master controller is suitable for judging the networking status of the photovoltaic-storage hybrid system based on the acquired data, and then sending a first control signal to the first switch, and / or sending a second control signal to each of the slave controllers to control each of the second switches. The slave controller is suitable for forwarding the received second control signal to the corresponding second switch.

4. The PID effect suppression and repair system of the photovoltaic storage hybrid system according to claim 2, characterized in that: The communication module includes a master controller and a plurality of slave controllers that communicate with each other; The master controller is adapted to collect AC side data of the photovoltaic-storage hybrid system, and each slave controller is adapted to correspondingly collect operating data of each photovoltaic-storage inverter and feed it back to the master controller; The main controller is adapted to determine the networking status of the photovoltaic-storage hybrid system based on the acquired data, and then send a corresponding control signal to the first switch and / or the second switch.

5. The PID effect suppression and repair system of the photovoltaic storage hybrid system according to claim 3, characterized in that: When all the photovoltaic and energy storage hybrid system's photovoltaic and energy storage inverters are in the grid-connected state, the specific control process of the communication module is as follows: The master controller polls all the photovoltaic and storage inverters through the slave controller to obtain the voltage data of the DC and AC sides of the photovoltaic and storage hybrid system, and calculates the amplitude of the AC side midpoint potential rise, and then directly sends a PID suppression instruction to the PID suppression module.

6. The PID effect suppression and repair system of the photovoltaic storage hybrid system according to claim 3, characterized in that: When some of the photovoltaic and energy storage hybrid system's photovoltaic and energy storage inverters are in the grid-connected state, the specific control process of the communication module is as follows: The master controller polls all grid-connected photovoltaic and storage inverters through the slave controller to obtain voltage data on the DC and AC sides of the photovoltaic and storage hybrid system, and calculates the AC side midpoint potential rise amplitude according to the potential distribution of the grid-connected photovoltaic and storage inverters, and then sends a PID suppression instruction to the PID suppression module to close the first switch corresponding to the PID suppression module; At the same time, the main controller controls the second switch of the PID suppression and repair module corresponding to the off-grid photovoltaic storage inverter to close, and determines the working status according to the obtained working data of the photovoltaic components and energy storage batteries corresponding to the off-grid photovoltaic storage inverter; If any one of the photovoltaic components and energy storage batteries corresponding to the off-grid photovoltaic inverter is in working condition, a PID suppression instruction is issued to the corresponding PID suppression and repair module; If the photovoltaic components and energy storage batteries corresponding to the off-grid photovoltaic inverter stop working, a PID repair instruction is sent to the corresponding PID suppression and repair module.

7. The PID effect suppression and repair system of the photovoltaic storage hybrid system according to claim 3, characterized in that: When all the photovoltaic and energy storage hybrid system's photovoltaic and energy storage inverters are in an off-grid state, the specific control process of the communication module is as follows: The master controller polls all the solar-storage inverters through the slave controller, and controls the second switches of all the PID suppression and repair modules to be closed; At the same time, the working status is determined based on the working data of the photovoltaic modules and energy storage batteries corresponding to all the photovoltaic storage inverters; If any one of the photovoltaic components and energy storage batteries corresponding to the photovoltaic inverter is in working state, a PID suppression instruction is sent to the corresponding PID suppression and repair module; If the photovoltaic components and energy storage batteries corresponding to the photovoltaic inverter stop working, a PID repair instruction is sent to the corresponding PID suppression and repair module.

8. The PID effect suppression and repair system of the photovoltaic storage hybrid system according to any one of claims 1 to 7, characterized in that: If the negative end of the photovoltaic module of each photovoltaic storage inverter is electrically connected to the DC side negative bus, the PID suppression and repair module is set at any position of the DC side bus midpoint of the photovoltaic storage inverter, the DC side negative bus and the negative end of the photovoltaic module.

9. The PID effect suppression and repair system of the photovoltaic storage hybrid system according to any one of claims 1 to 7, characterized in that: If there is no electrical connection between the negative end of the photovoltaic module of each photovoltaic storage inverter and the negative busbar on the DC side, the PID suppression and repair module is arranged at the negative end of the photovoltaic module.

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