PID effect suppression and restoration system of optical storage hybrid system

Abstract

The invention discloses a PID effect suppression and restoration system of an optical storage hybrid system. The PID effect suppression and restoration system comprises a PID suppression module and a plurality of PID suppression and restoration modules, the PID suppression module is arranged at a neutral point shared by the alternating current side of the optical storage hybrid system; each PID suppression and repair module is arranged on the direct current side of each optical storage inverter; when at least one optical storage inverter performs grid-connected work, the PID suppression module performs normal work, and meanwhile, the PID suppression and repair module corresponding to the grid-connected photovoltaic inverter stops working; and for the optical storage inverter in the off-grid state, the corresponding PID suppression and repair module performs PID suppression or repair according to the working states of the photovoltaic module and the energy storage battery. The system has the beneficial effects that the cooperative work of the direct current side PID suppression and restoration module and the alternating current side PID suppression module is controlled according to the working state of the optical storage hybrid system, and the PID effect suppression or restoration of the photovoltaic module under the grid-connected and off-grid state of the optical storage inverter in the system is realized.

Description

Technical Field

[0001] The present application relates to the technical field of new energy power generation, and particularly relates to a system for suppressing and repairing the PID effect of a photovoltaic and energy storage hybrid system. Background Art

[0002] The PID effect refers to the photovoltaic potential induced attenuation effect in a photovoltaic system. When the battery components are under high voltage for a long time, there is a leakage current between the glass and the encapsulation material, and a large amount of charge accumulates on the surface of the battery cells, resulting in a poor passivation effect on the surface of the battery cells. When the PID effect is severe, the power of a battery component will decay by more than 50%, thus affecting the power output of the entire battery string.

[0003] The existing solutions for solving the PID effect of a photovoltaic system include: (1) Directly grounding or grounding through a resistor the negative pole of the inverter bus; this solution is simple, low-cost, and has a significant effect.

[0004] (2) Adopting an AC-side virtual neutral point elevation scheme, where an external DC source is used to elevate the potential of the AC-side virtual neutral point with respect to the ground, so as to elevate the potential of the center point of the bus with respect to the ground, and thus indirectly elevate the potential of the negative pole of the component with respect to the ground.

[0005] (3) Achieving PID repair by applying a positive voltage between the negative pole of the photovoltaic array and the ground.

[0006] The above technical solutions have the following defects when used: For solution (1), grounding the negative pole of the inverter bus makes the potential of the positive pole of the component with respect to the ground high. If a ground fault occurs at the positive pole of the component, it will cause a short circuit of the battery panel, and if the maintenance personnel touch the positive pole, there will be a risk of electric shock or even a fire. For solution (2), when the inverter stops working at night, the relay inside the inverter disconnects, and the elevation of the AC-side virtual neutral point 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), usually a positive bias voltage or a positive voltage is applied to promote the ions (such as sodium ions) migrated to the battery cells to move out of the battery cells, but this process can only work when the inverter stops working. At the same time, the above solutions are all for photovoltaic systems, and the suppression of the PID effect cannot be achieved when applied to a photovoltaic and energy storage hybrid system. Summary of the Invention

[0007] One of the purposes of the present application is to provide a system for suppressing and repairing the PID effect of a photovoltaic and energy storage hybrid system that can solve at least one of the defects in the above background art.

[0008] To achieve at least one of the above objectives, the technical solution adopted in this application is as follows: A PID effect suppression and repair system for a hybrid photovoltaic and energy storage system, including 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 hybrid photovoltaic and energy storage system; each of the PID suppression and repair modules is respectively arranged at the DC side of the corresponding photovoltaic and energy storage inverter in the hybrid photovoltaic and energy storage system; when at least one photovoltaic and energy storage inverter is operating in parallel, the PID suppression module operates normally, and at the same time, the corresponding PID suppression and repair module of the photovoltaic inverter in parallel stops operating; for the photovoltaic and energy storage inverter in off-grid operation, the corresponding PID suppression and repair module performs PID suppression or repair according to the operating states of the photovoltaic modules and the energy storage battery.

[0009] Preferably, for the photovoltaic and energy storage inverter in off-grid operation, if any one of the photovoltaic modules and the energy storage battery is in an operating state, the corresponding PID suppression and repair module outputs voltage compensation so that the negative voltage of the photovoltaic module is raised to zero or close to zero; if both the photovoltaic modules and the energy storage battery stop operating, the corresponding PID suppression and repair unit applies a high voltage between the negative pole of the photovoltaic string and the ground.

[0010] 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 hybrid photovoltaic and energy storage system further includes a communication module, which is adapted to collect the operating data of the hybrid photovoltaic and energy storage system and control the first switch and the second switch to conduct or turn off according to the collected data, and then connect the PID suppression unit and / or the PID suppression and repair unit to the hybrid photovoltaic and energy storage system.

[0011] Preferably, the communication module includes a main controller and multiple slave controllers that communicate with each other; the main controller is adapted to collect the AC side data of the hybrid photovoltaic and energy storage system, and each slave controller is adapted to collect the operating data of the corresponding photovoltaic and energy storage inverter and feedback it to the main controller; the main controller is adapted to judge the networking state of the hybrid photovoltaic and energy storage system according to the obtained data, and then send a first control signal to the first switch and / or send a second control signal for controlling each second switch to each slave controller, and the slave controller is adapted to forward the received second control signal to the corresponding second switch.

[0012] Preferably, the communication module includes a main controller and a plurality of slave controllers that communicate with each other; the main controller is adapted to collect AC-side data of the photovoltaic-storage hybrid system, and each of the slave controllers is adapted to collect the operating data of each photovoltaic-storage inverter correspondingly and feedback it to the main controller; the main controller is adapted to judge the networking state of the photovoltaic-storage hybrid system according to the acquired data, and then directly send corresponding control signals to the first switch and / or the second switch.

[0013] Preferably, 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 polls all the photovoltaic-storage inverters through the slave controllers to obtain the voltage data of the DC side and the AC side of the photovoltaic-storage hybrid system, and calculates the uplift amplitude of the midpoint potential of the AC side, and then issues a PID suppression instruction to the PID suppression module.

[0014] Preferably, when some of 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 polls all the photovoltaic-storage inverters through the slave controllers to obtain the voltage data of the DC side and the AC side of the photovoltaic-storage hybrid system, and calculates the uplift amplitude of the midpoint potential of the AC side according to the potential distribution of the grid-connected photovoltaic-storage inverters, and then issues a PID suppression instruction to the PID suppression module, so that the first switch corresponding to the PID suppression module is closed; 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 be closed, and judges the working state according to the operating data of the photovoltaic module and the energy storage battery corresponding to the off-grid photovoltaic-storage inverter; if any one of the photovoltaic module and the energy storage battery corresponding to the off-grid photovoltaic-storage inverter is in the working state, issue a PID suppression instruction to the corresponding PID suppression and repair module; if both the photovoltaic module and the energy storage battery corresponding to the off-grid photovoltaic-storage inverter stop working, issue a PID repair instruction to the corresponding PID suppression and repair module.

[0015] Preferably, 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 polls all the photovoltaic-storage inverters through the slave controllers, and controls the second switches of all the PID suppression and repair modules to be closed; at the same time, judge the working state according to the operating data of the photovoltaic modules and the energy storage batteries corresponding to all the photovoltaic-storage inverters; if any one of the photovoltaic module and the energy storage battery corresponding to the photovoltaic-storage inverter is in the working state, issue a PID suppression instruction to the corresponding PID suppression and repair module; if both the photovoltaic module and the energy storage battery corresponding to the photovoltaic-storage inverter stop working, issue a PID repair instruction to the corresponding PID suppression and repair module.

[0016] Preferably, if the negative terminal of the photovoltaic module of each photovoltaic-storage inverter is electrically connected to the negative bus of the DC side, the PID suppression and repair module is arranged at any position of the midpoint of the DC side bus of the photovoltaic-storage inverter, the negative bus of the DC side, and the negative terminal of the photovoltaic module.

[0017] Preferably, if there is no electrical connection between the negative terminal of the photovoltaic module of each photovoltaic-storage inverter and the negative bus of the DC side, the PID suppression and repair module is arranged at the negative terminal of the photovoltaic module.

[0018] Compared with the prior art, the beneficial effects of the present application are as follows: According to the working state 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 the suppression or repair of the PID effect of the photovoltaic module in the grid-connected and off-grid states of the photovoltaic-storage inverter in the system, so as to solve the problem of PID effect accumulation of the photovoltaic module in the photovoltaic-storage hybrid system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall architecture of the present application.

[0020] Figure 2 It is a schematic diagram of the specific structure of the PID suppression and repair unit and the PID suppression unit in the present application.

[0021] Figure 3 It is a schematic diagram of the architecture of one example of the communication module in the present application.

[0022] Figure 4 It is a schematic diagram of the architecture of another example of the communication module in the present application.

[0023] Figure 5 It is a schematic diagram of the working process of the photovoltaic-storage hybrid system in the fully grid-connected state of the present application.

[0024] Figure 6 It is a schematic diagram of the overall architecture of the present application in the fully grid-connected state.

[0025] Figure 7 It is a timing diagram of the present application in the fully grid-connected state.

[0026] Figure 8 It is a schematic diagram of the working process of the photovoltaic-storage hybrid system in the hybrid state of the present application.

[0027] Figure 9 It is a schematic diagram of the overall architecture of the present application in the hybrid state.

[0028] Figure 10 It is a timing diagram of the present application in the hybrid state.

[0029] Figure 11Schematic diagram of the working process of the energy storage and photovoltaic hybrid system of this application in a fully off-grid state.

[0030] Figure 12 Schematic diagram of the overall architecture of this application in a fully off-grid state.

[0031] Figure 13 Schematic diagram of the timing sequence of this application in a fully off-grid state.

[0032] In the figure: PID suppression and repair unit 100, PID suppression unit 200, main controller 310, slave controller 320. Specific embodiments

[0033] Next, in combination with specific embodiments, this application will be further described. It should be noted that in the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions 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 can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0034] In the description of this application, it should be noted that for orientation terms, if there are terms such as "center", "horizontal", "vertical", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation and position relationship are based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0035] 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 do not necessarily need to describe a specific order or sequence.

[0036] In this application, unless otherwise clearly defined or limited, terms such as "installed", "connected", "linked", "fixed", etc. shall be understood in a broad sense. For example, it can be a connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In this application, unless otherwise clearly defined or limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over" and "on the top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "under the bottom of" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0038] The terms "comprising" and "having" and any variations thereof in the description and claims of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that comprises a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0039] One preferred embodiment of this application is as Figure 1 shown, a PID effect suppression and repair system for a photovoltaic and energy storage hybrid system, comprising a PID suppression module and multiple PID suppression and repair modules. The PID suppression module is arranged at the common neutral point on the AC side of the photovoltaic and energy storage hybrid system; each PID suppression and repair module is respectively arranged on the DC side of the corresponding photovoltaic and energy storage inverter of the photovoltaic and energy storage hybrid system. When at least one photovoltaic and energy storage inverter is working in parallel connection, the PID suppression module works normally, and at the same time, the PID suppression and repair module corresponding to the photovoltaic inverter in parallel connection stops working. For the photovoltaic and energy storage inverter in off-grid operation, the corresponding PID suppression and repair module performs PID suppression or repair according to the working states of the photovoltaic modules and the energy storage battery.

[0040] It should be known that the specific architecture of the photovoltaic and energy storage hybrid system is well-known to those skilled in the art. For the convenience of understanding, the specific architecture of the photovoltaic and energy storage hybrid system will be briefly described below. As Figure 1As shown in the figure, the hybrid photovoltaic and energy storage architecture includes multiple hybrid photovoltaic and energy storage inverters. The AC outputs of each hybrid photovoltaic and energy storage inverter are connected to the same three-phase AC power grid. Each AC output terminal of the hybrid photovoltaic and energy 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 hybrid photovoltaic and energy storage inverters share a common neutral point.

[0041] The structures of all hybrid photovoltaic and energy storage inverters are the same, and each includes a photovoltaic string, an energy 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 photovoltaic string and the DC / DC unit is connected in parallel with the branch formed by the series connection of the energy storage battery and the bidirectional DC / DC unit on the AC side of the DC / AC unit. Each hybrid photovoltaic and energy storage inverter is connected in parallel to the three-phase AC power grid through the AC side of the DC / AC unit. The AC side of the DC / AC unit of each hybrid photovoltaic and energy storage inverter is also connected to a load, so as to supply power to the load through the photovoltaic string or the energy storage battery, or even the AC power grid. Assuming the number of hybrid photovoltaic and energy storage inverters is N, each hybrid photovoltaic and energy storage inverter can be labeled as hybrid photovoltaic and energy storage inverter #1 to #N.

[0042] It should be noted that when applying the solution for suppressing the PID effect in the photovoltaic system in the background art to the above hybrid photovoltaic and energy storage system; if all the hybrid photovoltaic and energy storage inverters in the hybrid photovoltaic and energy storage system are in the grid-connected state, an AC-side PID suppression module can be used to suppress the PID effect; if there are off-grid hybrid photovoltaic and energy storage inverters in the hybrid photovoltaic and energy storage system, the AC-side PID suppression module alone cannot suppress the PID effect of the off-grid hybrid photovoltaic and energy storage inverters. Specifically, when the hybrid photovoltaic and energy storage inverter is in the off-grid state, the photovoltaic module has no energy output, but the energy storage battery can still provide energy for the hybrid photovoltaic and energy storage inverter. At this time, the negative electrode of the photovoltaic module is continuously at a negative voltage with respect to the ground; since the PID suppression module on the AC side cannot directly suppress the PID of the photovoltaic module in the off-grid state, the PID effect of the photovoltaic module will continue to accumulate at this time.

[0043] In the technical solution of the present application, by connecting a PID suppression module at the position of the common neutral point on the AC side of the hybrid photovoltaic and energy storage system, and at the same time connecting a PID suppression and repair module to the DC side of each hybrid photovoltaic and energy storage inverter; thus, when at least one hybrid photovoltaic and energy storage inverter in the hybrid photovoltaic and energy storage system is in the grid-connected state, the PID suppression module can be used to suppress the PID effect of the grid-connected hybrid photovoltaic and energy storage inverter; for the off-grid hybrid photovoltaic and energy storage inverter, the PID suppression and repair module can be used to suppress or repair the PID effect in combination with the working states of the photovoltaic module and the energy storage battery. Compared with the traditional method, the present application controls the coordinated work of the DC-side PID suppression and repair module and the AC-side PID suppression module according to the working state of the hybrid photovoltaic and energy storage system, and realizes the suppression or repair of the PID effect of the photovoltaic module in the grid-connected and off-grid states of the hybrid photovoltaic and energy storage inverter in the system, so as to solve the problem of PID effect accumulation of the photovoltaic module in the hybrid photovoltaic and energy storage system.

[0044] In this embodiment, for an off-grid PV energy storage inverter, if any one of the PV modules and the energy storage battery is in a working state, the corresponding PID suppression and repair module outputs voltage compensation to raise the negative voltage of the PV module to zero or close to zero, thereby suppressing the PID effect of the PV module. If both the PV module and the energy storage battery stop working, the corresponding PID suppression and repair unit applies a high voltage between the negative pole of the PV string and the ground, thereby performing PID repair on the PV module.

[0045] It can be understood that when any one of the PV module and the energy storage battery is in a working state, taking the energy storage battery being in a working state while the PV module stops working as an example; at this time, the energy storage battery will output energy, enabling the PV energy storage inverter to remain in a working state, which causes the negative voltage of the PV module with respect to the ground to continuously be a negative voltage, and further leads to the accumulation of the PID effect in the PV module. Since PID repair can only be performed when the PV energy storage inverter is shut down, voltage compensation is output through the PID suppression and repair module at this time to raise the negative voltage of the PV module with respect to the ground. When both the PV module and the energy storage battery are shut down, at this time the PV energy storage inverter is in a shutdown state, that is, the PID effect in the PV module no longer accumulates. Then, in this state, the PID suppression and repair module can perform PID repair on the PV module to restore the performance of the PV module.

[0046] In this embodiment, as Figure 1 shown, the PID suppression module includes a PID suppression unit 200 and a first switch S PID-AC , and the PID suppression unit 200 is connected between the neutral point shared by the AC side of the PV energy storage hybrid system and the ground through the first switch S PID-AC . When there is a grid-connected PV energy storage inverter in the PV energy storage hybrid system, the access of the PID suppression unit 200 can be achieved by closing the first switch S PID-AC , thereby realizing the PID suppression of the grid-connected PV energy storage inverter.

[0047] The PID suppression and repair module includes a PID suppression and repair unit 100 and a second switch S PID , and the PID suppression and repair unit 100 is connected between the DC side of the PV energy storage inverter and the ground through the second switch S PID ; since the number of PID suppression and repair modules corresponds to the number of PV energy storage inverters, the second switches S PID corresponding to each PID suppression and repair module can be respectively marked as S PID1 to S PIDN . When there is an off-grid PV energy storage inverter in the PV energy storage hybrid system, the second switch S PIDClosing it connects the PID suppression unit 200 to the off-grid photovoltaic energy storage inverter; then, PID suppression or PID repair can be performed according to the operating states of the photovoltaic modules and energy storage batteries in the off-grid photovoltaic energy storage inverter.

[0048] It can be understood that both the PID suppression unit and the PID suppression and repair unit adopt PID effect devices. There are various specific structures of the PID effect devices. For the convenience of understanding, several specific examples will be described in detail below.

[0049] Specifically, Example 1: As shown in (1) of Figure 2 the PID effect device includes a fuse.

[0050] Example 2: To ensure the stable operation of the fuse, as shown in (2) of Figure 2 the PID effect device includes a series-connected fuse and a fixed-value resistor.

[0051] Example 3: As shown in (3) of Figure 2 the PID effect device includes a series-connected switch and a diode. By controlling the closing and opening of the switch, the access and disconnection of the diode are realized, thereby suppressing the PID effect.

[0052] Example 4: As shown in (4) of Figure 2 the PID effect device includes a series-connected switch and a power supply. By controlling the closing and opening of the switch, the access and disconnection of the power supply are realized, and the PID effect is suppressed or repaired based on the output voltage of the power supply.

[0053] Example 5: To avoid reverse current in the power supply, as shown in (5) of Figure 2 the PID effect device includes a series-connected switch, a diode, and a power supply.

[0054] It should be noted that for the PID suppression and repair unit on the DC side, the above Example 4 or Example 5 can be directly used to suppress or repair the PID effect; of course, it can also be the combined use of 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 obtained by converting the power taken from the power grid through an AC-DC circuit. For the PID suppression unit on the AC side, since it needs to boost the voltage to suppress the PID effect, only the above Example 4 or Example 5 can be selected to suppress the PID effect; correspondingly, its power supply can be an independent power supply or obtained by taking power from the power grid.

[0055] In this embodiment, the specific installation position of the PID suppression and repair module mainly depends on the connection relationship between the photovoltaic module and the DC side busbar. As shown in Figure 1As shown, in a PV energy storage inverter, if there is an electrical connection between the negative terminal of the PV module and the negative DC bus, then the PID suppression and repair modules corresponding to each PV energy storage inverter can be set at any position among the midpoint of the DC bus, the negative DC bus, and the negative terminal of the PV module of the PV energy storage inverter. If there is no electrical connection between the negative terminal of the PV module and the negative DC bus of each PV energy storage inverter, then the PID suppression and repair module can only be set at the negative terminal of the PV module. For ease of understanding, this application will describe the following content by taking the case where the PV module is electrically connected to the negative DC bus and the PID suppression and repair module is connected to the negative DC bus as an example.

[0056] In this embodiment, the operation of the PID suppression module and the PID suppression and repair module can be controlled through a communication module. The communication module can collect the operation data of the PV energy storage hybrid system and control the first switch S PID-AC and the second switch S PID to conduct or turn off, so as to connect the PID suppression unit 200 and / or the PID suppression and repair unit 100 to the PV energy storage hybrid system to achieve the suppression or repair of the PID effect. There are various specific structures of the communication module for realizing communication control. For ease of understanding, the following will describe in detail through a specific structure.

[0057] Specifically, as Figure 3 shown, the communication module includes a main controller 310 and N slave controllers 320 corresponding to the number of PV energy storage inverters that communicate with each other. The main controller 310 can collect the AC side data of the PV energy storage hybrid system, and each slave controller 320 can correspondingly collect the operation data of each PV energy storage inverter and feedback it to the main controller 310. The main controller 310 can judge the networking status of the PV energy storage hybrid system according to the acquired data, and then send corresponding control signals to the first switch S PID-AC and / or the second switch S PID .

[0058] It can be understood that the main controller 310 and the slave controllers 320 are connected through a communication bus. There are various types of communication buses, such as local area network buses and RS485 buses, etc. In this embodiment, the RS485 bus is preferably adopted. There are mainly two specific control methods for the main controller 310 to control the first switch S PID-AC and the second switch S PID ; the first one is as Figure 3 shown, the main controller 310 can directly send the first control signal to the first switch S PID-AC , and at the same time, the main controller 310 can send the second control signal for controlling the second switch S PID to the slave controllers 320 through the communication bus, and then the slave controllers 320 can forward the received second control signal to the corresponding second switch SPID The second case is as follows Figure 4 shown. The main controller 310 can directly send the corresponding first control signal and second control signal to the first switch S PID-AC and the second switch S PID respectively. The above two control methods can both meet the requirements of this application, and those skilled in the art can select according to actual needs. For the convenience of subsequent content description, the first control method above is preferably adopted in this embodiment.

[0059] It should be known that the main controller 310, as the main node of the RS485 bus, is responsible for collecting and receiving various data, including the midpoint potential of the AC side of the photovoltaic and energy storage hybrid system, the negative terminal to ground voltage of the photovoltaic module PV, the output voltage of the photovoltaic module PV, and the working state of the energy storage battery, etc. The main controller 310 can judge the operating state of all photovoltaic and energy storage inverters based on the received data, thereby outputting control signals for the corresponding PID suppression module and the PID suppression and repair module, and calculating the corresponding regulation parameters.

[0060] The slave controller 320 serves as a slave node of the RS485 bus. Each slave controller 320 shares data such as the negative terminal to ground voltage of the photovoltaic module PV, the output voltage of the photovoltaic module PV, the working state of the energy storage battery, and the grid-connected and off-grid states of the photovoltaic and energy storage inverter collected through the RS485 bus to the main controller 310. The slave controller 320 can receive the control instructions from the main controller 310 and feedback them to the PID suppression and repair module, and at the same time calculate the regulation parameters of the PID suppression and repair module.

[0061] For the convenience of understanding, the following will describe in detail the specific process of the communication module controlling the PID suppression module and the PID suppression and repair module in combination with the working state of the photovoltaic and energy storage inverter.

[0062] As Figure 5 shown, when all the photovoltaic and energy storage inverters of the photovoltaic and energy 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 and energy storage inverters through the slave controller 320 to obtain the voltage data of the DC side and AC side of the photovoltaic and energy storage hybrid system. Among them, the DC side voltage data includes data such as the output voltage of the photovoltaic module and the negative terminal to ground voltage, and the AC side voltage data mainly includes the midpoint potential of the AC side. Then the main controller 310 calculates the elevation amplitude of the midpoint potential of the AC side based on the obtained voltage data, and then issues a PID suppression instruction as a control signal to the PID suppression module. Then the first switch S PID-AC corresponding to the PID suppression module closes, and then the PID suppression unit 200 performs voltage adjustment and feedbacks the execution result.

[0063] It should be noted that during the control process of the communication module when all the photovoltaic energy storage inverters are in the grid-connected state, as Figure 6 shown, the second switches S corresponding to all the PID suppression and repair modules PID1 to S PIDN are all in the off state. For the convenience of understanding, the control process of the communication module can be described by the timing diagram as Figure 7 shown. During the time period from t1 to t2, each slave controller 320 transmits the collected data to the master controller 310 through the RS485 bus. The master controller 310 replies to the slave controller 320 at time t2 within the set time to confirm receiving the data. Subsequently, the master controller 310 calculates the voltage boost amplitude and generates and issues the control signal during the time period from t3 to t4 according to the received data. Finally, at time t4, the PID suppression module on the AC side closes the corresponding first switch S PID-AC to suppress the PID effect of the photovoltaic modules of all the photovoltaic energy storage inverters by boosting the neutral point voltage on the AC side.

[0064] As Figure 8 shown, when some of the photovoltaic energy storage inverters in the photovoltaic energy storage hybrid system are in the grid-connected state, the specific control process of the communication module is as follows: The master controller 310 polls all the photovoltaic energy storage inverters through the slave controller 320 to obtain the voltage data on the DC side and the AC side of the photovoltaic energy storage hybrid system; among them, the DC side voltage data includes the output voltage of the photovoltaic modules and the negative pole-to-ground voltage and other data, and the AC side voltage data mainly includes the midpoint potential on the AC side. Then the master controller 310 calculates the boost amplitude of the midpoint potential on the AC side according to the potential distribution of the grid-connected photovoltaic energy storage inverters, and then issues a PID suppression instruction to the PID suppression module to make the corresponding first switch S of the PID suppression module PID-AC close. Subsequently, the PID suppression unit 200 performs voltage adjustment and feeds back the execution result.

[0065] Meanwhile, the master controller 310 controls the second switch S of the PID suppression and repair module corresponding to the off-grid photovoltaic energy storage inverter PIDClose it, and judge the working state according to the working data of the photovoltaic modules and energy storage batteries corresponding to the off-grid PV energy storage inverter. If any one of the photovoltaic modules and energy storage batteries corresponding to the off-grid PV energy storage inverter is in the working state, send a PID suppression instruction to the corresponding PID suppression and repair module, so that the PID suppression and repair unit raises the negative pole-to-ground voltage of the photovoltaic module to 0 or close to 0, thereby suppressing the PID effect of the photovoltaic module. If both the photovoltaic module and the energy storage battery corresponding to the off-grid PV energy 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 applies a high voltage to the negative terminal of the photovoltaic module, thereby repairing the accumulated PID effect of the photovoltaic module.

[0066] It should be known that during the control process in which the communication module is based on the grid-connected state of some PV energy storage inverters, as Figure 9 shown, the second switch S of the PID suppression and repair module corresponding to the off-grid PV energy storage inverter PID is closed, and the second switches S of the PID suppression and repair modules corresponding to the remaining grid-connected PV energy storage inverters PID are disconnected. For example, it can be set that the first to m PV energy storage inverters operate off-grid, then the PID suppression and repair units 100 on the DC sides of the first to m PV energy storage inverters are enabled; the PID suppression and repair units 100 on the DC sides of the (m + 1)-th to N-th continuously grid-connected PV energy storage inverters remain shut down. The PID suppression module on the AC side continuously suppresses the PID effect through the closing of the first switch S PID-AC .

[0067] For easy understanding, the control process of the communication module can be described by a timing diagram as Figure 10 shown. During the time period from t1 to t4, the working processes of the main controller 310 and the slave controller 320 are basically the same as the foregoing content, and the difference is that the control signals generated by the main controller 310 respectively control the first switch S PID-AC and some of the second switches S PID . Finally, at the moment t4, the PID suppression module on the AC side closes the corresponding first switch S PID-AC according to the received high-level first control signal, thereby suppressing the PID effect of the photovoltaic modules of all PV energy storage inverters by raising the neutral point voltage on the AC side. At the same time, at the moment t4, the PID suppression and repair module on the DC side of the off-grid PV energy storage inverter closes the corresponding second switches S PID1 to S PIDm according to the received high-level second control signal.

[0068] As Figure 11As shown, when all the photovoltaic energy storage inverters in the photovoltaic energy 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 the photovoltaic energy storage inverters through the slave controller 320, and controls the second switch S of all the PID suppression and repair modules PID to close; at the same time, it judges the working state according to the working data of the photovoltaic modules and energy storage batteries corresponding to all the photovoltaic energy storage inverters, and calculates the DC side voltage boost amplitude. If any one of the photovoltaic module and energy storage battery corresponding to the photovoltaic energy storage inverter is in the working state, a PID suppression instruction is sent to the corresponding PID suppression and repair module, so that the PID suppression and repair unit boosts and compensates the negative electrode to ground voltage of the photovoltaic module to 0 or close to 0, thereby suppressing the PID effect of the photovoltaic module. If both the photovoltaic module and energy storage battery corresponding to the photovoltaic energy storage 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.

[0069] It should be known that in the control process where the communication module is based on all the photovoltaic energy storage inverters being in the off-grid state, as Figure 12 shown, the second switches S corresponding to all the PID suppression and repair modules PID1 to S PIDN are all in the closed state, and the first switch S corresponding to the PID suppression module PID-AC is in the open state. For easy understanding, the control process of the communication module can be described by the timing diagram as Figure 13 shown. During the time period from t1 to t4, the working processes of the main controller 310 and the slave controller 320 are basically the same as the foregoing content. The difference is that the control signal generated by the main controller 310 only controls the second switch S PID . Finally, all the PID suppression and repair modules close the corresponding second switch S PID at the moment t4 according to the received high-level control signal, so as to perform PID suppression or repair according to the working states of the photovoltaic modules and energy storage batteries corresponding to each photovoltaic energy storage inverter.

[0070] The above describes the basic principle, main features and advantages of the present application. Those skilled in the art of this industry should understand that the present application is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present application. Without departing from the spirit and scope of the present application, the present application will have various changes and improvements, and these changes and improvements all fall within the scope of the present application claimed. 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 and energy storage hybrid system, characterized in that, Including: PID suppression module; The PID suppression module is arranged at the neutral point shared by the AC side of the photovoltaic-storage hybrid system; And Multiple PID suppression and repair modules; Each of the PID suppression and repair modules is respectively arranged at the DC side of the corresponding photovoltaic-storage inverter of the photovoltaic-storage hybrid system; When at least one photovoltaic-storage inverter is operating in grid connection, the PID suppression module operates normally, and at the same time, the PID suppression and repair module corresponding to the grid-connected photovoltaic inverter stops operating; For the off-grid photovoltaic-storage inverter, the corresponding PID suppression and repair module performs PID suppression or repair according to the operating states of the photovoltaic modules and the energy storage battery.

2. The PID effect suppression and repair system of the optical storage hybrid system according to claim 1, characterized in that, For the off-grid photovoltaic-storage inverter, if any one of the photovoltaic modules and the energy storage battery is in an operating state, the corresponding PID suppression and repair module outputs voltage compensation so that the negative voltage of the photovoltaic module is lifted to zero or close to zero; If both the photovoltaic module and the energy storage battery stop operating, the corresponding PID suppression and repair unit applies a high voltage between the negative pole of the photovoltaic string and the ground.

3. The PID effect suppression and repair system of the photovoltaic and energy storage hybrid system according to claim 2, wherein 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 further includes a communication module, which is adapted to collect the operating data of the photovoltaic-storage hybrid system and control the first switch and the second switch to conduct or turn off according to the collected data, so as to connect the PID suppression unit and / or the PID suppression and repair unit to the photovoltaic-storage hybrid system.

4. The PID effect suppression and repair system for the optical storage hybrid system according to claim 3, characterized in that, The communication module includes a main controller and multiple slave controllers that communicate with each other; The main controller is adapted to collect the AC side data of the photovoltaic-storage hybrid system, and each of the slave controllers is adapted to collect the operating data of the corresponding photovoltaic-storage inverter and feedback it to the main controller; The main controller is adapted to judge the grid connection state of the photovoltaic-storage hybrid system according to the obtained data, and then send a first control signal to the first switch and / or send a second control signal for controlling each of the second switches to each of the slave controllers, and the slave controllers are adapted to forward the received second control signal to the corresponding second switch.

5. The PID effect suppression and repair system of the optical storage hybrid system according to claim 3, characterized in that, The communication module includes a main controller and multiple slave controllers that communicate with each other; The main controller is adapted to collect the AC side data of the photovoltaic-storage hybrid system, and each of the slave controllers is adapted to collect the operating data of the corresponding photovoltaic-storage inverter and feedback it to the main controller; The main controller is adapted to judge the grid connection state of the photovoltaic-storage hybrid system according to the obtained data, and then send corresponding control signals to the first switch and / or the second switch.

6. The PID effect suppression and repair system for the optical storage hybrid system according to claim 4, wherein 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 polls all the photovoltaic-storage inverters through the slave controllers, obtains the voltage data of the DC side and the AC side of the photovoltaic-storage hybrid system, calculates the lifting amplitude of the midpoint potential of the AC side, and then directly issues a PID suppression instruction to the PID suppression module.

7. The PID effect suppression and repair system for the optical storage hybrid system according to claim 4, characterized in that When some of the photovoltaic energy storage inverters in the photovoltaic energy 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 grid-connected photovoltaic energy storage inverters through the slave controller, obtains the voltage data of the DC side and the AC side of the photovoltaic energy storage hybrid system, calculates the uplift amplitude of the midpoint potential of the AC side according to the potential distribution of the grid-connected photovoltaic energy storage inverters, and then issues a PID suppression instruction to the PID suppression module, so that the first switch corresponding to the PID suppression module is closed; At the same time, the main controller controls the second switch of the PID suppression and repair module corresponding to the off-grid photovoltaic energy storage inverter to be closed, and judges the working state according to the working data of the photovoltaic module and the energy storage battery corresponding to the off-grid photovoltaic energy storage inverter; If any one of the photovoltaic module and the energy storage battery corresponding to the off-grid photovoltaic energy storage inverter is in the working state, a PID suppression instruction is issued to the corresponding PID suppression and repair module; If both the photovoltaic module and the energy storage battery corresponding to the off-grid photovoltaic energy storage inverter stop working, a PID repair instruction is issued to the corresponding PID suppression and repair module.

8. The PID effect suppression and repair system for the optical storage hybrid system according to claim 4, characterized in that, When all the photovoltaic energy storage inverters in the photovoltaic energy storage hybrid system are in the off-grid state, the specific control process of the communication module is as follows: The main controller polls all the photovoltaic energy 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, judge the working state according to the working data of the photovoltaic modules and the energy storage batteries corresponding to all the photovoltaic energy storage inverters; If any one of the photovoltaic module and the energy storage battery corresponding to the photovoltaic energy storage inverter is in the working state, a PID suppression instruction is issued to the corresponding PID suppression and repair module; If both the photovoltaic module and the energy storage battery corresponding to the photovoltaic energy storage inverter stop working, a PID repair instruction is issued to the corresponding PID suppression and repair module.

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

10. The PID effect suppression and repair system for the optical storage hybrid system according to any one of claims 1-8, characterized in that If the negative terminal of the photovoltaic module of each photovoltaic energy storage inverter is not electrically connected to the negative bus of the DC side, the PID suppression and repair module is set at the negative terminal of the photovoltaic module.

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