Control method and device of optical storage system and optical storage system

Abstract

The invention discloses a control method and device of an optical storage system and the optical storage system, and belongs to the field of optical storage systems. The control method of the optical storage system comprises the following steps: under the condition that the grid-connected point voltage of the grid-connected point is not in a target voltage range, determining an adjustment parameter based on the type of the grid-connected point impedance; and adjusting the inverter based on the adjustment parameter, so that the adjusted grid-connected point voltage is stabilized within the target voltage range. According to the control method of the optical storage system, the overvoltage or undervoltage threshold of grid-connected and off-grid switching triggered by the voltage of the grid-connected point can be reduced, so that the frequency of grid-connected and off-grid switching is reduced, the synergistic effect of the optical storage system and the power grid is improved, and the stability and reliability of the optical storage system are improved.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic storage systems, and in particular, relates to a control method and device for photovoltaic storage systems and a photovoltaic storage system. Background Art

[0002] In the related technology, for the photovoltaic storage system that supports on-grid and off-grid switching, when the impedance of the grid connection point is large, the grid connection point voltage will be raised or lowered when generating electricity to the grid or drawing electricity from the grid, and even the overvoltage or undervoltage threshold of the on-grid and off-grid switching will be triggered, thereby triggering the photovoltaic storage system to switch from the grid-connected state to the off-grid state, thereby disconnecting from the grid. After that, the grid connection point voltage returns to normal, and the system switches back to the grid-connected state. Then, when the photovoltaic storage system generates electricity to the grid or draws electricity from the grid, it triggers the switching to the off-grid state, and so on and so forth. As a result, the photovoltaic storage system is restricted in drawing electricity from the grid and generating electricity to the grid, which is not conducive to the synergistic effect between the photovoltaic storage system and the grid as well as the stability and reliability of the photovoltaic storage system. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the related art. To this end, the present application proposes a control method, device and photovoltaic storage system for a photovoltaic storage system, which can reduce the overvoltage or undervoltage threshold of the grid-connected point voltage triggering and off-grid switching, so as to reduce the frequency of on-grid and off-grid switching, improve the synergy between the photovoltaic storage system and the power grid, and improve the stability and reliability of the photovoltaic storage system.

[0004] In a first aspect, the present application provides a control method for a photovoltaic storage system, wherein the photovoltaic storage system comprises an inverter and an on-grid switching device, wherein the inverter is connected to a first end of the on-grid switching device; a second end of the on-grid switching device is connected to a grid connection point; impedance exists between the grid connection point and the power grid; the method comprises: When the grid connection point voltage of the grid connection point is not within the target voltage range, the adjustment parameter is determined based on the type of grid connection point impedance corresponding to the photovoltaic storage system; the target voltage range is a preset voltage range for keeping the photovoltaic storage system in a grid-connected operation state unchanged; The inverter is adjusted based on the adjustment parameters so that the adjusted grid-connected point voltage is stabilized within the target voltage range, thereby reducing the switching frequency of the grid-connected and off-grid states of the photovoltaic storage system.

[0005] According to the control method of the photovoltaic storage system of the present application, when the grid connection point voltage is not within the target voltage range, the adjustment parameters are determined based on the category of the grid connection point impedance corresponding to the photovoltaic storage system, and then the inverter is adjusted based on the adjustment parameters to stabilize the adjusted grid connection point voltage within the target voltage range. When the inverter generates electricity to the grid or draws electricity from the grid, the grid connection point voltage can be indirectly adjusted to be within the target voltage range based on adjusting the inverter, thereby reducing the overvoltage or undervoltage threshold of the grid connection point voltage triggering on-grid and off-grid switching, thereby reducing the frequency of on-grid and off-grid switching, improving the synergy between the photovoltaic storage system and the grid, and improving the stability and reliability of the photovoltaic storage system.

[0006] According to one embodiment of the present application, the target voltage range is determined based on the grid-connected and off-grid switching over-voltage and under-voltage thresholds and at least one of the categories; the grid-connected and off-grid switching over-voltage and under-voltage thresholds include the grid-connected and off-grid switching under-voltage threshold and the grid-connected and off-grid switching over-voltage threshold; the categories include resistive, inductive and capacitive.

[0007] According to an embodiment of the present application, the target voltage range is determined based on the grid-connected and off-grid switching over-voltage and under-voltage thresholds and at least one of the categories, including: In the case where the category is resistive, the first voltage threshold is determined as the maximum boundary value of the target voltage range and the first voltage threshold is less than the grid-connected and off-grid switching overvoltage threshold, and the second voltage threshold is determined as the minimum boundary value of the target voltage range and the second voltage threshold is greater than the grid-connected and off-grid switching undervoltage threshold; In the case where the category is inductive, the second voltage threshold is determined as the minimum boundary value of the target voltage range and the second voltage threshold is greater than the grid-connected and off-grid switching undervoltage threshold; When the category is capacitive, the second voltage threshold is determined as the minimum boundary value of the target voltage range and the second voltage threshold is greater than the on-grid and off-grid switching undervoltage threshold, wherein the second voltage threshold is less than the first voltage threshold.

[0008] According to an embodiment of the present application, determining the adjustment parameter based on the type of the grid connection point impedance corresponding to the photovoltaic storage system includes: In the case where the category is resistive, determining the adjustment parameter as the active power of the inverter; In the case where the category is inductive, determining the adjustment parameter as the reactive power of the inverter; When the category is capacitive, the regulating parameter is determined as the reactive power of the inverter.

[0009] According to an embodiment of the present application, adjusting the inverter based on the adjustment parameter so that the adjusted grid connection point voltage is stabilized within the target voltage range includes: When the category is resistive and the grid-connected point is in a power generation state, reducing the adjustment parameter until the adjusted grid-connected point voltage is stabilized within the target voltage range; When the category is resistive and the grid-connected point is in a power-taking state, increasing the adjustment parameter until the adjusted grid-connected point voltage is stabilized within the target voltage range; In the case where the category is inductive, increasing the adjustment parameter until the adjusted grid connection point voltage is stabilized within the target voltage range; When the category is capacitive, the adjustment parameter is reduced until the adjusted grid connection point voltage is stabilized within the target voltage range.

[0010] According to an embodiment of the present application, after adjusting the inverter based on the adjustment parameter so that the adjusted grid connection point voltage is stabilized within the target voltage range, the method further includes: Obtaining the target active power of the grid-connected point at at least one collection moment; When the category is inductive and the absolute value of the target active power determined based on the target active power at the at least one acquisition moment shows a decreasing trend, reducing the adjustment parameter to control the grid connection point voltage to increase until the adjustment parameter is reduced to 0; When the category is capacitive and the absolute value of the target active power determined based on the target active power at at least one acquisition moment shows a decreasing trend, the adjustment parameter is increased to control the grid connection point voltage to increase until the adjustment parameter is reduced to 0.

[0011] According to an embodiment of the present application, before adjusting the inverter based on the adjustment parameter, the method further includes: Obtaining the target active power of the grid-connected point at multiple collection moments; When it is determined based on the target active powers at the multiple acquisition moments that the absolute value of the target active power shows an increasing trend and the grid connection point voltage is not within the target voltage range, an adjustment parameter is determined based on the category.

[0012] In a second aspect, the present application provides a control device for a photovoltaic storage system, the photovoltaic storage system comprising an inverter and an on-grid switching device, the inverter being connected to a first end of the on-grid switching device; the second end of the on-grid switching device being connected to a grid connection point; there being an impedance between the grid connection point and the power grid; the device comprising: A first processing module, when the grid connection point voltage of the grid connection point is not within a target voltage range, determines an adjustment parameter based on the type of impedance of the grid connection point; the target voltage range is a preset voltage range for keeping the photovoltaic storage system in a grid-connected operation state unchanged; The second processing module is used to adjust the inverter based on the adjustment parameters so that the adjusted grid-connected point voltage is stabilized within the target voltage range, thereby reducing the switching frequency of the grid-connected and off-grid states of the photovoltaic storage system.

[0013] According to the control device of the photovoltaic storage system of the present application, when the grid connection point voltage is not within the target voltage range, the adjustment parameters are determined based on the type of grid connection point impedance, and then the inverter is adjusted based on the adjustment parameters to stabilize the adjusted grid connection point voltage within the target voltage range. When the photovoltaic storage system generates electricity to the power grid or draws electricity from the power grid, the grid connection point voltage can be indirectly adjusted to be within the target voltage range based on adjusting the inverter, thereby reducing the overvoltage or undervoltage threshold of the grid connection point voltage triggering on-grid and off-grid switching, thereby reducing the frequency of on-grid and off-grid switching, improving the synergy between the photovoltaic storage system and the power grid, and improving the stability and reliability of the photovoltaic storage system.

[0014] In a third aspect, the present application provides a photovoltaic storage system, comprising: An inverter connected to a first end of the on-grid and off-grid switching device; A grid-connected and off-grid switching device, wherein the second end of the grid-connected and off-grid switching device is connected to the grid connection point; A photovoltaic module, wherein the photovoltaic module is connected to the inverter; An energy storage module, wherein the energy storage module is connected to the inverter; The photovoltaic storage system operates based on the control method of the photovoltaic storage system as described in the first aspect.

[0015] In a fourth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the control method of the optical storage system as described in the first aspect above.

[0016] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the control method of the photovoltaic storage system as described in the first aspect above.

[0017] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects: By determining the adjustment parameters based on the grid connection point impedance category when the grid connection point voltage is not within the target voltage range, and then adjusting the inverter based on the adjustment parameters, so that the adjusted grid connection point voltage is stabilized within the target voltage range, it is possible to indirectly adjust the grid connection point voltage to be within the target voltage range based on adjusting the inverter when the grid connection point generates electricity to the grid or draws electricity from the grid, thereby reducing the overvoltage or undervoltage threshold of the grid connection point voltage triggering on-grid and off-grid switching, thereby reducing the frequency of on-grid and off-grid switching, improving the synergy between the photovoltaic storage system and the grid, and improving the stability and reliability of the photovoltaic storage system.

[0018] Furthermore, by determining the adjustment parameter as the active power of the inverter when the category is resistive, and determining the adjustment parameter as the reactive power of the inverter when the category is inductive or capacitive, the reliability of the adjustment parameter can be improved, thereby improving the effectiveness of subsequent adjustment of the inverter based on the adjustment parameter.

[0019] Furthermore, by respectively reducing the adjustment parameter when the grid connection point impedance category is resistive and the grid connection point is in a power-drawing state, and increasing the adjustment parameter when the grid connection point impedance category is resistive and the grid connection point is in a power generation state; increasing the adjustment parameter when the grid connection point impedance category is inductive; and reducing and adjusting the adjustment parameter when the grid connection point impedance category is capacitive, so as to adjust the grid connection point voltage until the adjusted grid connection point voltage is stabilized within the target voltage range, it is possible to implement a variety of adjustment parameter adjustment methods based on the grid connection point impedance category, improve the flexibility and pertinence of the adjustment method, thereby improving the accuracy and reliability of the adjustment result, and further improving the synergy between the photovoltaic storage system and the power grid as well as the stability and reliability of the photovoltaic storage system.

[0020] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a flow chart of a control method of a photovoltaic storage system provided in an embodiment of the present application; Figure 2 This is one of the result schematic diagrams of the control method of the photovoltaic storage system provided in the embodiment of the present application; Figure 3 This is the second result schematic diagram of the control method of the photovoltaic storage system provided in the embodiment of the present application; Figure 4 This is the third result schematic diagram of the control method of the photovoltaic storage system provided in the embodiment of the present application; Figure 5 This is the fourth result schematic diagram of the control method of the photovoltaic storage system provided in the embodiment of the present application; Figure 6 This is the fifth result schematic diagram of the control method of the photovoltaic storage system provided in the embodiment of the present application; Figure 7 This is the sixth result schematic diagram of the control method of the photovoltaic storage system provided in the embodiment of the present application; Figure 8 This is the seventh result schematic diagram of the control method of the photovoltaic storage system provided in the embodiment of the present application; Fig. 9 It is one of the structural schematic diagrams of the optical storage system provided in the embodiment of the present application; Fig.10 This is the second structural schematic diagram of the optical storage system provided in the embodiment of the present application; Fig.11 This is the third structural diagram of the optical storage system provided in the embodiment of the present application; Fig.12 is a schematic diagram of the structure of a control device for a photovoltaic storage system provided in an embodiment of the present application; Fig.13 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0023] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0024] In conjunction with the accompanying drawings, the control method of the optical storage system, the control device of the optical storage system, the optical storage system and the readable storage medium provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0025] The control method of the optical storage system may be applied to a terminal, and may be specifically executed by hardware or software in the terminal.

[0026] The control method of the photovoltaic storage system provided in the embodiment of the present application can be executed by the photovoltaic storage system or a functional module or functional entity in the photovoltaic storage system that can implement the control method of the photovoltaic storage system. The control method of the photovoltaic storage system provided in the embodiment of the present application is described below using the photovoltaic storage system as an example of the execution subject.

[0027] like Figure 1 As shown, the control method of the photovoltaic storage system includes: step 110 and step 120.

[0028] The photovoltaic storage system may include a photovoltaic module and an energy storage module.

[0029] Among them, photovoltaic modules can be used to achieve photovoltaic power generation based on photovoltaic arrays.

[0030] The energy storage module can be used to store the electricity generated by photovoltaic power generation.

[0031] The photovoltaic storage system also includes an inverter and an on-grid and off-grid switching device.

[0032] An inverter is a device that converts direct current into alternating current and can be used in photovoltaic storage systems.

[0033] The on-grid switching device is a device that connects or disconnects the system from the grid point.

[0034] In actual implementation, the inverter can convert the direct current generated by the solar panels of the photovoltaic storage system into alternating current to power the load or the grid.

[0035] The load may be electrical equipment in a household or commercial facility.

[0036] The inverter and the load are connected to the first end of the on-grid and off-grid switching device.

[0037] The second end of the on-grid and off-grid switching device is connected to the grid connection point.

[0038] There is impedance between the grid connection point and the power grid.

[0039] Among them, the grid connection point can be the connection point for power conversion between the photovoltaic storage system and the power grid.

[0040] In the actual implementation process, when the grid connection point between the photovoltaic storage system and the power grid remains connected, the photovoltaic storage system is in a grid-connected operation state, that is, a grid-connected state; when the grid connection point between the photovoltaic storage system and the power grid remains disconnected, the photovoltaic storage system is in an off-grid operation state, that is, an off-grid state.

[0041] Among them, when connected to the grid, the photovoltaic storage system can transmit excess photovoltaic power generation to the power grid; or, it can also obtain electricity from the power grid when photovoltaic power generation is insufficient.

[0042] When off-grid, the photovoltaic storage system is an independent power supply system that can supply power to energy storage modules and loads based on its own photovoltaic modules.

[0043] In the actual implementation process, for the photovoltaic storage system that supports switching between grid-connected and off-grid states, when the grid is normal, it is in the grid-connected state. When a grid abnormality is identified (such as grid power failure or grid overvoltage or undervoltage, etc.), it switches to the off-grid state. When the grid is normal, it switches back to the grid-connected state.

[0044] For scenarios where the impedance of the grid connection point is large, such as when the transmission cable is too long, resulting in resistance between the grid and the photovoltaic storage system and a large equivalent impedance, the voltage at the grid connection point will decrease when the photovoltaic storage system draws power from the grid, and will increase when generating power to the grid, which may trigger the undervoltage or overvoltage threshold for switching between on-grid and off-grid states, and then trigger the switching from the on-grid state to the off-grid state, thereby disconnecting the photovoltaic storage system from the grid.

[0045] After being disconnected from the grid, the photovoltaic storage system no longer draws electricity from the grid connection point or generates electricity to the grid connection point, and the voltage at the grid connection point returns to normal. When it is identified that the grid voltage is normal, the photovoltaic storage system switches from the off-grid state to the grid connection state. If the grid voltage is abnormal when drawing electricity from the grid or generating electricity, it switches to the off-grid state again.

[0046] Step 110: When the grid connection point voltage of the grid connection point is not within the target voltage range, determining the adjustment parameter based on the type of the grid connection point impedance corresponding to the photovoltaic storage system; In this step, the target voltage range is a preset voltage range used to keep the photovoltaic energy storage system in a grid-connected operating state.

[0047] In actual implementation, the target voltage range may be preset and determined based on an overvoltage threshold (grid-to-grid switching overvoltage threshold) or an undervoltage threshold (grid-to-grid switching undervoltage threshold) that triggers switching between on-grid and off-grid states.

[0048] Among them, the overvoltage threshold is the grid connection point voltage threshold that triggers the photovoltaic energy storage system to switch from grid-connected to off-grid state when the grid connection point voltage is too high.

[0049] The undervoltage threshold is the grid connection point voltage threshold that triggers the PV storage system to switch from grid-connected to off-grid state when the grid connection point voltage is too low.

[0050] In some embodiments, the target voltage range may be determined as a grid connection point voltage range with a voltage value greater than an undervoltage threshold as the minimum boundary voltage and a voltage value less than an overvoltage threshold as the maximum boundary voltage.

[0051] like Fig. 9 , Fig.10 and Fig.11 As shown, the grid connection point impedance can be an equivalent resistance, equivalent inductance or equivalent capacitance abstracted from the transmission cable.

[0052] In actual implementation, too long transmission cables will result in large impedance between the power grid and the photovoltaic storage system.

[0053] The types of grid connection point impedance can include resistive, inductive and capacitive.

[0054] Among them, the impedance of resistive impedance is constant. In the actual implementation process, resistive impedance converts electrical energy into thermal energy; the impedance of inductive impedance and capacitive impedance changes with frequency. In the actual implementation process, inductive impedance and capacitive impedance alternately store and release energy in the AC circuit.

[0055] The adjustment parameters are parameters used to adjust the inverter.

[0056] The adjustment parameters may include active power or reactive power of the inverter.

[0057] Reactive power is the power generated in an AC circuit due to the phase difference between current and voltage caused by the presence of inductance or capacitance elements.

[0058] It is understandable that when the grid connection point voltage of the grid connection point is not within the target voltage range, the types of grid connection point impedance corresponding to the photovoltaic storage system are different, and the determined adjustment parameters are different.

[0059] The specific method for determining the target voltage range will be described in the following embodiments, and will not be elaborated in this application.

[0060] Step 120: adjust the inverter based on the adjustment parameters so that the adjusted grid-connected point voltage is stabilized within the target voltage range, thereby reducing the switching frequency of the grid-connected and off-grid states of the photovoltaic storage system.

[0061] In this step, the adjusted grid connection point voltage is stabilized within the target voltage range, which can be understood as making the grid connection point voltage smaller than the maximum boundary voltage of the target voltage range and larger than the minimum boundary voltage of the target voltage range.

[0062] In the actual implementation process, the adjusted grid connection point voltage can be stabilized within the target voltage range by being stabilized at the maximum boundary voltage, or at a voltage value close to the maximum boundary voltage but less than the maximum boundary voltage; or it can be stabilized at the minimum boundary voltage, or at a voltage value close to the minimum boundary voltage but greater than the minimum boundary voltage.

[0063] It can be understood that the inverter can be adjusted based on the adjustment parameters determined by the grid connection point impedance category to adjust the grid connection point voltage, so that the adjusted grid connection point voltage is stable within the target voltage range, even if the grid connection point voltage is lower than the maximum boundary voltage of the target voltage range and higher than the minimum boundary voltage of the target voltage range, so that the grid connection point voltage does not trigger the overvoltage or undervoltage threshold for the photovoltaic storage system to switch from the grid-connected state to the off-grid state, thereby reducing the switching frequency of the photovoltaic storage system from the grid-connected state to the off-grid state.

[0064] During the research and development process, the inventors discovered that for a photovoltaic storage system that supports on-grid and off-grid switching, when the impedance of the grid connection point is large, the grid connection point voltage will be raised or lowered when generating electricity to the grid or drawing electricity from the grid, and even the overvoltage or undervoltage threshold of the on-grid and off-grid switching will be triggered, thereby triggering the photovoltaic storage system to switch from the grid-connected state to the off-grid state, thereby disconnecting from the grid. Then, when the grid connection point voltage returns to normal and the grid voltage is normal, it switches back to the grid-connected state, and then triggers the switching to the off-grid state when the photovoltaic storage system generates electricity to the grid or draws electricity from the grid, and so on and so forth. As a result, the photovoltaic storage system is restricted in drawing electricity from the grid and generating electricity to the grid, which is not conducive to the synergistic effect between the photovoltaic storage system and the grid as well as the stability and reliability of the photovoltaic storage system.

[0065] In the present application, when the grid connection point voltage is not within the target voltage range, the adjustment parameters are determined based on the category of the grid connection point impedance corresponding to the photovoltaic storage system, and then the inverter is adjusted based on the adjustment parameters corresponding to each grid connection point impedance category, so that the adjusted grid connection point voltage is stabilized within the target voltage range, that is, the grid connection point voltage is less than the maximum boundary voltage of the target voltage range and greater than the minimum boundary voltage of the target voltage range. When the inverter generates electricity to the grid or draws electricity from the grid, the grid connection point voltage can be indirectly adjusted to be within the target voltage range based on adjusting the inverter, thereby reducing the overvoltage or undervoltage threshold of the grid connection point voltage triggering the on-grid switching, thereby reducing the frequency of on-grid switching, improving the synergy between the photovoltaic storage system and the grid, and improving the stability and reliability of the photovoltaic storage system.

[0066] According to the control method of the photovoltaic storage system provided in the embodiment of the present application, when the grid connection point voltage at the grid connection point is not within the target voltage range, the adjustment parameters are determined based on the category of the grid connection point impedance corresponding to the photovoltaic storage system, and the inverter is adjusted based on the adjustment parameters to stabilize the adjusted grid connection point voltage within the target voltage range. When the grid connection point generates electricity to the power grid or draws electricity from the power grid, the grid connection point voltage can be indirectly adjusted to be within the target voltage range based on adjusting the inverter, thereby reducing the overvoltage or undervoltage threshold of the grid connection point voltage triggering on-grid and off-grid switching, thereby reducing the frequency of on-grid and off-grid switching, improving the synergy between the photovoltaic storage system and the power grid, and improving the stability and reliability of the photovoltaic storage system.

[0067] The following describes how to determine and apply the adjustment parameters.

[0068] In some embodiments, determining the adjustment parameter based on the type of the grid connection point impedance corresponding to the photovoltaic energy storage system may include: In the case where the category is resistive, the regulation parameter is determined as the active power of the inverter; In the case where the category is inductive, the regulation parameter is determined as the reactive power of the inverter; In the case of the capacitive category, the control variable is determined as the reactive power of the inverter.

[0069] In this embodiment, the active power of the inverter may include the output active power or the absorbed active power of the inverter, wherein the sign of the output active power is positive and the sign of the absorbed active power is negative, that is, the output active power is a positive value and the absorbed active power is a negative value.

[0070] The reactive power of the inverter may include the output reactive power or the absorbed reactive power of the inverter, wherein the sign of the output reactive power is positive and the sign of the absorbed reactive power is negative, that is, the output reactive power is a positive value and the absorbed reactive power is a negative value.

[0071] It can be understood that an increase in the active power of the inverter may include: an increase in the absolute value of the inverter's output active power or a decrease in the absolute value of the absorbed active power; a decrease in the active power of the inverter may include: an increase in the absolute value of the inverter's output active power or an increase in the absolute value of the absorbed active power; an increase or decrease in the reactive power of the inverter is the same as above.

[0072] It should be noted that the increase or decrease of absorbed active power in the following embodiments refers to the increase or decrease of the absolute value of absorbed active power, and the increase or decrease of absorbed active power refers to the increase or decrease of the absolute value of absorbed active power, and the same applies to absorbed reactive power.

[0073] It can be understood that when the grid-connected point impedance corresponding to the photovoltaic storage system is resistive, the adjustment parameter can be determined as the active power of the inverter, so that the adjusted grid-connected point voltage can be stabilized within the target voltage range based on the active power of the inverter; when the grid-connected point impedance corresponding to the photovoltaic storage system is inductive or capacitive, the adjustment parameter can be determined as the reactive power of the inverter, so that the adjusted grid-connected point voltage can be stabilized within the target voltage range.

[0074] In the actual implementation process, the output active power of the inverter can be defined as positive, and the absorbed active power can be defined as negative; the active power direction of the grid connection point is defined as generating power to the grid as positive, and taking power from the grid as negative; the load uses electricity, and the load power is always positive; then the relationship between the inverter active power, the load active power, and the grid connection point active power is:

[0075] in, is the inverter active power, is the load active power, is the active power of the grid-connected point.

[0076] It can be understood that based on the relationship between the inverter active power, the load active power and the grid connection point active power, when the grid connection point impedance is a resistive resistor, the inverter active power is equal to the sum of the load active power and the grid connection point active power. The grid connection point active power can be adjusted by adjusting the inverter active power, thereby adjusting the grid connection point voltage.

[0077] In some embodiments, the relationship between the grid connection point power and the grid connection point voltage can be derived based on the grid voltage, the grid connection point current, and the equivalent resistance voltage, etc., to obtain the correlation between the grid connection point power and the grid connection point voltage when the grid connection point impedance is resistive. The derivation process is as follows: Assume the grid voltage is:

[0078] in, is the grid voltage, is the grid voltage amplitude, is positive, is the angular frequency, For time.

[0079] Assume the grid-connected current is:

[0080] in, is the grid-connected current, is the grid-connected point current amplitude, It can be positive or negative. A positive value means that the system generates electricity to the grid, and a negative value means that the system draws electricity from the grid. is the angular frequency, For time.

[0081] The voltage on the equivalent resistance of the grid-connected point impedance is:

[0082] in, is the equivalent resistance voltage, is the equivalent resistance of the grid connection point, is the grid-connected point current.

[0083] The grid connection point voltage is the grid voltage plus the equivalent resistance voltage:

[0084] in, is the grid voltage, is the grid voltage, is the equivalent resistance voltage.

[0085] Right now:

[0086] in, is the grid voltage, is the grid voltage amplitude, is the grid-connected point current amplitude, is the equivalent resistance of the grid connection point, is the angular frequency, For time.

[0087] The voltage amplitude at the grid connection point is:

[0088] in, is the voltage amplitude at the grid connection point, is the grid voltage amplitude, is the grid-connected point current amplitude, is the equivalent resistance of the grid connection point.

[0089] The relationship between the grid-connected point current and the grid-connected point active power is:

[0090] in, is the grid-connected point current amplitude, is the voltage amplitude at the grid connection point, is the active power of the grid-connected point.

[0091] Substituting the relation between the grid-connected point current and the grid-connected point active power into the grid-connected point voltage amplitude formula, we get:

[0092] in, is the voltage amplitude at the grid connection point, is the active power of the grid connection point, is the grid voltage amplitude, is the equivalent resistance of the grid connection point.

[0093] Then the relationship between the grid-connected point active power and the grid-connected point voltage is:

[0094] in, is the voltage amplitude at the grid connection point, is the grid voltage amplitude, is the active power at the grid connection point, and R is the equivalent resistance.

[0095] It can be understood that the grid connection point voltage is related to the grid voltage, the grid connection point equivalent resistance and the grid connection point active power. Under normal circumstances, the grid voltage and the grid connection point equivalent resistance are basically fixed, and the grid connection point voltage is only positively correlated with the grid connection point active power. The grid connection point active power can be adjusted by adjusting the inverter active power, and then the grid connection point voltage can be adjusted, so that the adjusted grid connection point voltage is stable within the target voltage range.

[0096] When the grid connection point impedance is inductive, there is an equivalent inductance, a phase difference exists between the current and the voltage on the equivalent inductance, and reactive power exists in the circuit.

[0097] In the actual implementation process, since the inverter provides a current source for the grid connection point, the reactive power of the grid connection point can be adjusted by adjusting the reactive power of the inverter, thereby adjusting the voltage of the grid connection point.

[0098] In some embodiments, the relationship between the grid point power and the grid point voltage can be derived based on the grid voltage, the grid point current, and the equivalent inductor voltage, and the correlation between the grid point power and the grid point voltage can be obtained when the grid point impedance is inductive. The derivation process is as follows: Assume the grid voltage is:

[0099] in, is the grid voltage, is the grid voltage amplitude, is positive, is the angular frequency, For time.

[0100] When there is power interaction at the grid connection point, since the grid connection point impedance is inductive, the grid connection point voltage amplitude and phase may be offset from the grid voltage. Therefore, the grid connection point voltage is assumed to be:

[0101] in, is the grid voltage, is the voltage amplitude at the grid connection point, is the angular frequency, For time, The initial phase.

[0102] Assuming that the grid-connected point current and grid-connected point voltage are in phase, they are:

[0103] in, is the grid-connected current, is the grid-connected point current amplitude, It can be positive or negative. A positive value means that the system generates electricity to the grid, and a negative value means that the system draws electricity from the grid. is the angular frequency, For time, The initial phase.

[0104] The voltage across the equivalent inductor is:

[0105] in, is the equivalent inductor voltage, L is the equivalent inductance, is the grid-connected point current amplitude, is the angular frequency, For time, The initial phase.

[0106] The grid voltage is the grid connection point voltage plus the equivalent inductor voltage:

[0107] in, is the grid voltage, is the grid voltage, is the equivalent inductor voltage.

[0108] Right now:

[0109] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, L is the equivalent inductance, is the grid-connected point current amplitude, is the angular frequency, For time, The initial phase.

[0110] The relationship between the grid-connected point current and the grid-connected point active power is:

[0111] in, is the grid-connected point current amplitude, is the voltage amplitude at the grid connection point, is the active power of the grid-connected point.

[0112] Substituting the above formula that the grid voltage is the grid connection point voltage plus the equivalent inductance voltage, we get:

[0113] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, is the active power at the grid connection point, L is the equivalent inductance, is the angular frequency, For time, The initial phase.

[0114] Then the relationship between the grid-connected point active power and the grid-connected point voltage is:

[0115] in, is the voltage amplitude at the grid connection point, is the grid voltage amplitude, is the active power of the grid connection point, is the angular frequency, and L is the equivalent inductance.

[0116] It can be understood that the grid connection point voltage is related to the grid connection point active power, and no matter whether the photovoltaic storage system generates electricity to the grid or draws electricity from the grid (no matter whether ig or Ppcc is positive or negative), the grid connection point voltage is reduced. When it is lower than the set grid-connected and off-grid switching undervoltage threshold UswtMin, the grid-connected and off-grid switching switch will be disconnected, and the photovoltaic storage system will be disconnected from the grid and enter the off-grid state; therefore, when the equivalent impedance is inductive, the grid connection point voltage can be adjusted by controlling the reactive power of the grid connection point.

[0117] In some embodiments, the expressions of the grid connection point voltage and the active power and reactive power can be derived first, and the correlation between the grid connection point voltage and the active power and reactive power can be obtained when the grid connection point impedance is inductive reactance. The specific derivation process is as follows: The current corresponding to the active power at the grid connection point is:

[0118] in, is the current corresponding to the active power at the grid connection point, is the current amplitude corresponding to the active power at the grid connection point, is the angular frequency, For time, The initial phase.

[0119] The current phase corresponding to the active power at the grid connection point is consistent with the grid voltage phase, and the amplitude of the current corresponding to the active power is:

[0120] in, is the current amplitude corresponding to the active power at the grid connection point, is the active power of the grid connection point, is the voltage amplitude at the grid connection point.

[0121] Assume that the reactive power of the grid-connected point is , the reactive current corresponding to the reactive power of the grid connection point is:

[0122] in, is the reactive current corresponding to the reactive power at the grid connection point, is the amplitude of reactive current corresponding to the reactive power at the grid connection point, is the angular frequency, For time, The initial phase.

[0123] The current phase corresponding to the reactive power at the grid connection point is 90 degrees different from the grid voltage phase. The amplitude of the current corresponding to the reactive power is:

[0124] in, is the amplitude of reactive current corresponding to the reactive power at the grid connection point, is the reactive power at the grid connection point, is the voltage amplitude at the grid connection point.

[0125] The equivalent inductor voltage is:

[0126] in, is the equivalent inductor voltage, is the current amplitude corresponding to the active power at the grid connection point, is the amplitude of reactive current corresponding to the reactive power at the grid connection point, L is the equivalent inductance, is the angular frequency, For time, The initial phase.

[0127] The grid voltage is the grid connection point voltage plus the equivalent inductor voltage:

[0128] in, is the grid voltage, Grid connection voltage, Equivalent inductor voltage.

[0129] Right now:

[0130] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, is the current amplitude corresponding to the active power at the grid connection point, is the amplitude of reactive current corresponding to the reactive power at the grid connection point, L is the equivalent inductance, is the angular frequency, For time, The initial phase.

[0131] Substituting the expressions of the grid-connected point reactive power and the corresponding current and the grid-connected point active power and the corresponding current, we can get:

[0132] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, is the active power of the grid connection point, is the reactive power at the grid connection point, L is the equivalent inductance, is the angular frequency, For time, The initial phase.

[0133] Then the expressions of grid connection point voltage, grid connection point active power and reactive power are as follows:

[0134] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, is the active power of the grid connection point, is the reactive power at the grid connection point, L is the equivalent inductance, is the angular frequency.

[0135] In the actual implementation process, the grid voltage, angular frequency and equivalent inductance of the grid connection point are basically stable and can be considered as fixed values.

[0136] It is understandable that the grid connection point voltage is positively correlated with the grid connection point reactive power. The grid connection point reactive power can be adjusted by adjusting the inverter reactive power, thereby adjusting the grid connection point voltage, so that the adjusted grid connection point voltage is stabilized within the target voltage range.

[0137] In some embodiments, the relationship between the grid connection point power and the grid connection point voltage can be derived based on the grid voltage, the grid connection point current, and the equivalent capacitor voltage, and the correlation between the grid connection point power and the grid connection point voltage can be obtained when the grid connection point impedance is capacitive. The derivation process is as follows: Assume the grid voltage is:

[0138] in, is the grid voltage, is the grid voltage amplitude, is positive, is the angular frequency, For time.

[0139] When there is power interaction at the grid connection point, since the grid connection point impedance is capacitive, the grid connection point voltage amplitude and phase may be offset from the grid voltage. Therefore, the grid connection point voltage is assumed to be:

[0140] in, is the grid voltage, is the voltage amplitude at the grid connection point, is the angular frequency, For time, The initial phase.

[0141] Assuming that the grid-connected point current and grid-connected point voltage are in phase, they are:

[0142] in, is the grid-connected current, is the grid-connected point current amplitude, It can be positive or negative. A positive value means that the system generates electricity to the grid, and a negative value means that the system draws electricity from the grid. is the angular frequency, For time, The initial phase.

[0143] The voltage on the equivalent capacitor is:

[0144] in, is the equivalent capacitor voltage, C is the equivalent capacitor, is the grid-connected point current amplitude, is the angular frequency, For time, The initial phase.

[0145] The grid voltage is the grid connection point voltage plus the equivalent inductor voltage:

[0146] in, is the grid voltage, is the grid voltage, is the equivalent capacitor voltage.

[0147] Right now:

[0148] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, C is the equivalent capacitance, is the grid-connected point current amplitude, is the angular frequency, For time, The initial phase.

[0149] The relationship between the grid-connected point current and the grid-connected point active power is:

[0150] in, is the grid-connected point current amplitude, is the voltage amplitude at the grid connection point, is the active power of the grid-connected point.

[0151] Substituting the above formula that the grid voltage is the grid connection point voltage plus the equivalent inductance voltage, we get:

[0152] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, is the active power at the grid connection point, C is the equivalent capacitance, is the angular frequency, For time, The initial phase.

[0153] Then the relationship between the grid-connected point active power and the grid-connected point voltage is:

[0154] in, is the voltage amplitude at the grid connection point, is the grid voltage amplitude, is the active power of the grid connection point, is the angular frequency, and C is the equivalent capacitance.

[0155] It can be understood that the grid connection point voltage is related to the grid connection point active power, and no matter whether the photovoltaic storage system generates electricity to the grid or draws electricity from the grid (no matter whether ig or Ppcc is positive or negative), the grid connection point voltage is reduced. When it is lower than the set grid-connected and off-grid switching undervoltage threshold UswtMin, the grid-connected and off-grid switching switch will be disconnected, and the photovoltaic storage system will be disconnected from the grid and enter the off-grid state; therefore, when the equivalent impedance is capacitive, the grid connection point voltage can be adjusted by controlling the reactive power of the grid connection point.

[0156] In some embodiments, the expressions of the grid connection point voltage and the active power and reactive power can be derived first to obtain the correlation between the grid connection point voltage and the active power and reactive power when the equivalent impedance is capacitive. The specific derivation process is as follows: The current corresponding to the active power at the grid connection point is:

[0157] in, is the current corresponding to the active power at the grid connection point, is the current amplitude corresponding to the active power at the grid connection point, is the angular frequency, For time, The initial phase.

[0158] The current phase corresponding to the active power at the grid connection point is consistent with the grid voltage phase, and the amplitude of the current corresponding to the active power is:

[0159] in, is the current amplitude corresponding to the active power at the grid connection point, is the active power of the grid connection point, is the voltage amplitude at the grid connection point.

[0160] Assume that the reactive power of the grid-connected point is , the reactive current corresponding to the reactive power of the grid connection point is:

[0161] in, is the reactive current corresponding to the reactive power at the grid connection point, is the amplitude of reactive current corresponding to the reactive power at the grid connection point, is the angular frequency, For time, The initial phase.

[0162] The current phase corresponding to the reactive power at the grid connection point is 90 degrees different from the grid voltage phase. The amplitude of the current corresponding to the reactive power is:

[0163] in, is the amplitude of reactive current corresponding to the reactive power at the grid connection point, is the reactive power at the grid connection point, is the voltage amplitude at the grid connection point.

[0164] The equivalent capacitor voltage is:

[0165] in, is the equivalent capacitor voltage, is the current amplitude corresponding to the active power at the grid connection point, is the amplitude of reactive current corresponding to the reactive power at the grid connection point, C is the equivalent capacitance, is the angular frequency, For time, The initial phase.

[0166] The grid voltage is the grid connection point voltage plus the equivalent capacitor voltage:

[0167] in, is the grid voltage, Grid connection voltage, Equivalent capacitor voltage.

[0168] Right now:

[0169] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, is the current amplitude corresponding to the active power at the grid connection point, is the amplitude of reactive current corresponding to the reactive power at the grid connection point, C is the equivalent capacitance, is the angular frequency, For time, The initial phase.

[0170] Substituting the expressions of the grid-connected point reactive power and the corresponding current and the grid-connected point active power and the corresponding current, we can get:

[0171] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, is the active power of the grid connection point, is the reactive power at the grid connection point, C is the equivalent capacitance, is the angular frequency, For time, The initial phase.

[0172] Then the expressions of grid connection point voltage, grid connection point active power and reactive power are:

[0173] in, is the grid voltage amplitude, is the voltage amplitude at the grid connection point, is the active power of the grid connection point, is the reactive power at the grid connection point, C is the equivalent inductance, is the angular frequency.

[0174] In the actual implementation process, the grid voltage, angular frequency and equivalent capacitance of the grid connection point are basically stable and can be considered as fixed values.

[0175] It is understandable that the grid connection point voltage is negatively correlated with the grid connection point reactive power. The grid connection point reactive power can be adjusted by adjusting the inverter reactive power, thereby adjusting the grid connection point voltage, so that the adjusted grid connection point voltage is stable within the target voltage range.

[0176] According to the control method of the photovoltaic storage system provided in the embodiment of the present application, the reliability of the adjustment parameter can be improved by determining the adjustment parameter as the active power of the inverter when the category is resistive, and determining the adjustment parameter as the reactive power of the inverter when the category is inductive or capacitive, so as to improve the effectiveness of subsequent adjustment of the inverter based on the adjustment parameter.

[0177] In some embodiments, adjusting the inverter based on the adjustment parameter so that the adjusted grid connection point voltage is stable within the target voltage range may include: When the type is resistive and the grid-connected point is in a power generation state, the adjustment parameter is reduced until the adjusted grid-connected point voltage is stabilized within the target voltage range; When the type is resistive and the grid connection point is in the power-taking state, increase the adjustment parameter until the adjusted grid connection point voltage is stable within the target voltage range; When the category is inductive, increase the adjustment parameter until the adjusted grid connection point voltage is stable within the target voltage range.

[0178] In the case of capacitive type, the adjustment parameter is reduced until the adjusted grid connection point voltage is stabilized within the target voltage range.

[0179] In this embodiment, the grid connection point is in a power generation state, that is, the photovoltaic storage system generates electricity for the power grid.

[0180] The grid-connected point is in the power-drawing state, that is, the photovoltaic storage system draws power from the grid.

[0181] It can be understood that when the grid connection point impedance is resistive, the active power of the inverter can be reduced or increased based on the power generation or power extraction status of the grid connection point, thereby adjusting the grid connection point voltage so that the grid connection point voltage is stabilized within the target voltage range; when the grid connection point impedance is inductive, the reactive power of the inverter can be increased to adjust the grid connection point voltage so that the grid connection point voltage is stabilized within the target voltage range; when the grid connection point impedance is capacitive, the reactive power of the inverter can be reduced to adjust the grid connection point voltage so that the grid connection point voltage is stabilized within the target voltage range.

[0182] Among them, when the grid connection point impedance is resistive, reducing the adjustment parameter, that is, reducing the active power of the inverter, may include increasing the absorbed active power of the inverter or reducing the output active power of the inverter; increasing the adjustment parameter, that is, increasing the active power of the inverter, may include reducing the absorbed active power of the inverter or increasing the output active power of the inverter.

[0183] When the grid-connected point impedance is inductive or capacitive, reducing the adjustment parameter, i.e. reducing the reactive power of the inverter, may include increasing the absorbed reactive power of the inverter or reducing the output reactive power of the inverter; increasing the adjustment parameter, i.e. increasing the reactive power of the inverter, may include reducing the absorbed reactive power of the inverter or increasing the output reactive power of the inverter.

[0184] In the actual implementation process, when the impedance of the grid connection point is resistive, when the photovoltaic storage system generates electricity to the grid, that is, when the grid connection point is in the power generation state, the active power of the inverter increases, the grid connection point voltage increases, and when the grid connection point voltage is higher than the set grid-connected and off-grid switching overvoltage threshold, the grid-connected and off-grid switching switch will be disconnected, and the photovoltaic storage system will be disconnected from the grid and enter the off-grid state.

[0185] It can be understood that when the photovoltaic storage system generates electricity for the power grid, when the grid connection point voltage rises to the maximum boundary voltage of the target voltage range or is less than the maximum boundary voltage and has a small difference with the maximum boundary voltage, the active power of the inverter can be reduced to control the grid connection point voltage to be stable at the maximum boundary voltage, or to be stable at a voltage value less than the maximum boundary voltage and has a small difference with the maximum boundary voltage, thereby avoiding the disconnection of the grid-connected and off-grid switching switch.

[0186] For example, Figure 2As shown in the figure, when the impedance of the grid connection point is resistive and the photovoltaic storage system generates electricity to the grid, at time t1, the active power of the inverter increases (the output active power of the inverter increases), the grid connection point power increases, and the grid connection point voltage increases; at time t2, the grid connection point voltage reaches the maximum boundary voltage UrefMax of the set target voltage range, then the active power of the inverter is reduced (the output active power of the inverter is reduced), and the further increase of the grid connection point voltage is limited, so that the grid connection point voltage is stabilized at UrefMax; at time t3, the active power of the inverter decreases, and the grid connection point voltage decreases accordingly.

[0187] When the photovoltaic storage system draws power from the grid, that is, the grid connection point is in the power-drawing state, the active power of the inverter decreases (the absorbed active power of the inverter increases), the grid connection point voltage decreases, and when the grid connection point voltage is lower than the set grid-connected and off-grid switching undervoltage threshold, the grid-connected and off-grid switching switch will be disconnected, and the photovoltaic storage system will be disconnected from the grid and enter the off-grid state.

[0188] It can be understood that, when the photovoltaic storage system draws electricity from the grid, when the grid-connected point voltage is reduced to the minimum boundary voltage of the target voltage range or to a voltage greater than the minimum boundary voltage and with a small difference from the minimum boundary voltage, the grid-connected point voltage can be controlled to be stable at the minimum boundary voltage, or to a voltage value greater than the minimum boundary voltage and with a small difference from the minimum boundary voltage, by increasing the inverter active power (i.e., reducing the inverter's absorbed active power or increasing the inverter's output active power) to avoid disconnection of the grid-connected and off-grid switching switch.

[0189] For example, Figure 3 As shown in the figure, when the impedance of the grid connection point is resistive and the photovoltaic storage system draws power from the grid, at time t1, the active power of the inverter decreases (the absorbed active power of the inverter increases), the grid connection point power decreases, and the grid connection point voltage decreases; at time t2, the grid connection point voltage reaches the minimum boundary voltage UrefMin of the set target voltage range, then the active power of the inverter is increased (the absorbed active power of the inverter is reduced), and the further decrease of the grid connection point voltage is limited, so that the grid connection point voltage is stabilized at UrefMin; at time t3, the active power of the inverter increases, and the grid connection point voltage increases.

[0190] When the photovoltaic storage system draws power from the grid, the voltage at the grid connection point decreases when the load active power increases, and when the voltage at the grid connection point is lower than the set grid-connected and off-grid switching undervoltage threshold, the grid-connected and off-grid switching switch will be disconnected, and the photovoltaic storage system will be disconnected from the grid and enter an off-grid state.

[0191] It can be understood that when the load power increases and the grid-connected point voltage is reduced to the minimum boundary voltage of the target voltage range or to a voltage greater than the minimum boundary voltage and with a small difference from the minimum boundary voltage, the active power of the inverter can be increased to control the grid-connected point voltage to be stable at the minimum boundary voltage, or to a voltage value greater than the minimum boundary voltage and with a small difference from the minimum boundary voltage, thereby avoiding the disconnection of the grid-connected and off-grid switching switch.

[0192] For example, Figure 4 As shown in the figure, when the impedance of the grid connection point is resistive and the photovoltaic storage system draws power from the grid, at time t1, the load power increases, the active power of the grid connection point decreases (the absorbed active power increases), resulting in a decrease in the voltage at the grid connection point; at time t2, the grid connection point voltage reaches the minimum boundary voltage UrefMin of the set target voltage range, then the active power of the inverter is increased to limit the further decrease of the grid connection point voltage, so that the grid connection point voltage is stabilized at UrefMin; at time t3, the load power decreases, the grid connection point voltage increases, and the active power of the synchronous control inverter decreases.

[0193] When the impedance of the grid connection point is inductive, when the photovoltaic storage system generates electricity to the grid or draws electricity from the grid, the grid connection point voltage decreases when the active power of the inverter increases or decreases, and when the grid connection point voltage is lower than the set grid-connected and off-grid switching undervoltage threshold, the grid-connected and off-grid switching switch will be disconnected, and the photovoltaic storage system will be disconnected from the grid and enter the off-grid state.

[0194] Among them, the grid-connected point power is positively correlated with the grid-connected point voltage and the grid-connected point reactive power, that is, when the grid-connected point reactive power increases, the grid-connected point voltage increases; when the grid-connected point reactive power decreases, the grid-connected point voltage decreases; and the grid-connected point reactive power is positively correlated with the reactive power of the inverter, that is, when the reactive power of the inverter increases, the grid-connected point reactive power increases; when the reactive power of the inverter decreases, the grid-connected point reactive power decreases.

[0195] It can be understood that when the grid connection point impedance is inductive, when the photovoltaic storage system generates electricity to the grid or draws electricity from the grid, the grid connection point voltage drops. When the grid connection point voltage drops to the minimum boundary voltage of the target voltage range or to a voltage greater than the minimum boundary voltage and with a small difference from the minimum boundary voltage, the grid connection point reactive power can be increased by increasing the inverter reactive power, thereby increasing the grid connection point voltage, thereby controlling the grid connection point voltage to be stable at the minimum boundary voltage, or to be stable at a voltage value greater than the minimum boundary voltage and with a small difference from the minimum boundary voltage, thereby limiting the further drop of the grid connection point voltage and avoiding the disconnection of the grid-connected and off-grid switching switch.

[0196] For example, Figure 5As shown in the figure, when the grid connection point impedance is inductive and the photovoltaic storage system generates electricity to the grid, at time t1, the active power of the inverter increases, the grid connection point power increases, and the grid connection point voltage decreases; at time t2, the grid connection point voltage reaches the minimum boundary voltage UrefMin of the set target voltage range, then the reactive power of the inverter is increased to stabilize the grid connection point voltage at UrefMin; at time t3, the active power of the inverter decreases, and the grid connection point voltage increases.

[0197] For example, Figure 6 As shown in the figure, when the impedance of the grid connection point is inductive and the photovoltaic storage system draws power from the grid, at time t1, the absorbed active power of the inverter increases (the active power of the inverter decreases), the grid connection point power decreases, and the grid connection point voltage decreases; at time t2, the grid connection point voltage reaches the minimum boundary voltage UrefMin of the set target voltage range, then the reactive power of the inverter is increased to stabilize the grid connection point voltage at UrefMin; at time t3, the active power of the inverter increases and the grid connection point voltage rises.

[0198] When the impedance of the grid connection point is capacitive, when the photovoltaic storage system generates electricity to the grid or draws electricity from the grid, the grid connection point voltage decreases when the active power of the inverter increases or decreases, and when the grid connection point voltage is lower than the set grid-connected and off-grid switching undervoltage threshold, the grid-connected and off-grid switching switch will be disconnected, and the photovoltaic storage system will be disconnected from the grid and enter the off-grid state.

[0199] Among them, the grid-connected point power is the grid-connected point voltage size and the grid-connected point reactive power negatively correlated, that is, when the grid-connected point reactive power decreases, the grid-connected point voltage increases; when the grid-connected point reactive power increases, the grid-connected point voltage decreases; and the grid-connected point reactive power is positively correlated with the reactive power of the inverter, that is, when the reactive power of the inverter increases, the grid-connected point reactive power increases; when the reactive power of the inverter decreases, the grid-connected point reactive power decreases.

[0200] It can be understood that when the grid connection point impedance is capacitive, when the photovoltaic storage system generates electricity to the grid or draws electricity from the grid, the grid connection point voltage drops. When the grid connection point voltage drops to the minimum boundary voltage of the target voltage range or to a voltage greater than the minimum boundary voltage and with a small difference from the minimum boundary voltage, the grid connection point reactive power can be reduced by reducing the inverter reactive power, thereby increasing the grid connection point voltage, thereby controlling the grid connection point voltage to be stable at the minimum boundary voltage, or to a voltage value greater than the minimum boundary voltage and with a small difference from the minimum boundary voltage, thereby limiting the further drop of the grid connection point voltage and avoiding the disconnection of the grid-connected and off-grid switching switch.

[0201] For example, Figure 7As shown in the figure, when the grid connection impedance is capacitive and the photovoltaic storage system generates electricity to the grid, at time t1, the active power of the inverter increases, the grid connection power increases, and the grid connection voltage decreases; at time t2, the grid connection voltage reaches the minimum boundary voltage UrefMin of the set target voltage range, then the reactive power of the inverter is reduced to stabilize the grid connection voltage at UrefMin; at time t3, the active power of the inverter decreases and the grid connection voltage increases.

[0202] For example, Figure 8 As shown in the figure, when the grid connection point impedance is capacitive and the photovoltaic storage system draws power from the grid, at time t1, the absorbed active power of the inverter increases (the active power of the inverter decreases), the grid connection point power decreases, and the grid connection point voltage decreases; at time t2, the grid connection point voltage reaches the minimum boundary voltage UrefMin of the set target voltage range, then the reactive power of the inverter is increased to stabilize the grid connection point voltage at UrefMin; at time t3, the active power of the inverter decreases and the grid connection point voltage increases.

[0203] According to the control method of the photovoltaic storage system provided in the embodiment of the present application, by reducing or increasing the adjustment parameter when the grid connection point impedance is resistive, increasing the adjustment parameter when the grid connection point impedance is inductive, and reducing the adjustment parameter when the grid connection point impedance is capacitive, the grid connection point voltage is adjusted until the adjusted grid connection point voltage is stabilized within the target voltage range. This can achieve an adjustment method for multiple adjustment parameters based on the grid connection point impedance category, improve the flexibility and specificity of the adjustment method, thereby improving the accuracy and reliability of the adjustment result, and further improving the synergy between the photovoltaic storage system and the power grid and the stability and reliability of the photovoltaic storage system.

[0204] In some embodiments, after adjusting the inverter based on the adjustment parameter so that the adjusted grid connection point voltage is stabilized within the target voltage range, the method may further include: Obtaining the target active power of the grid-connected point at at least one acquisition time; When the category is inductive and the absolute value of the target active power determined based on the target active power at at least one acquisition moment shows a decreasing trend, the adjustment parameter is reduced to control the grid connection point voltage to increase until the adjustment parameter is reduced to 0; When the category is capacitive and the absolute value of the target active power determined based on the target active power at at least one acquisition moment shows a decreasing trend, the adjustment parameter is increased to control the grid connection point voltage to increase until the adjustment parameter increases to 0.

[0205] In this embodiment, the target active power may be the active power of the grid connection point.

[0206] The at least one acquisition moment may include one or more acquisition moments.

[0207] The multiple collection moments may be multiple collection moments based on a certain time interval.

[0208] For example, there are five collection moments every one second, such as five collection moments at the first second, the second, the third second, the fourth second, and the fifth second.

[0209] Of course, in other embodiments, there may be other multiple collection moments based on other time intervals, which is not limited in the present application.

[0210] It can be understood that the number of target active powers collected at multiple collection moments corresponds to the number of collection moments, that is, M target active powers can be collected at M collection moments, where M is a positive integer.

[0211] The decreasing trend of the absolute value of the target active power can be understood as: the output active power is decreasing or the absorbed active power is increasing.

[0212] The situation where the absolute value of the target active power shows a decreasing trend may include: the absolute value of the target active power at a certain collection moment is less than the absolute value of the target active power at the previous moment; or the absolute value of the target active power at multiple consecutive collection moments gradually decreases; or the absolute value fluctuation of the target active power at multiple consecutive collection moments decreases.

[0213] The stepwise decrease of the absolute value of the target active power can be understood as: based on the sequence of the acquisition moments, the absolute value of the target active power gradually decreases.

[0214] The reduction in fluctuation of the absolute value of the target active power can be understood as follows: based on the sequence of the acquisition moments, the absolute value of the target active power is in a generally decreasing trend.

[0215] For example, 5 target active powers at 5 consecutive acquisition moments are obtained, wherein, except that the absolute value of the target active power at the 3rd acquisition moment is greater than the absolute value of the target active power at the 2nd acquisition moment, the absolute values ​​of the target active powers at the remaining acquisition moments are all less than the absolute values ​​of the target active powers at the previous acquisition moments, then it can be considered that the absolute values ​​of the target active powers at the 5 acquisition moments are decreasing. It can be understood that, in the case where the grid connection point impedance is inductive, after the grid connection point voltage is stabilized at the minimum boundary voltage of the target voltage range or a voltage value greater than the minimum boundary voltage and having a small difference from the minimum boundary voltage based on increasing the reactive power of the inverter, and because the absolute value of the target active power at the grid connection point is decreasing, that is, the grid connection point voltage is increasing, then the reactive power of the inverter can be reduced to 0, so that the grid connection point voltage rises based on the decreasing trend of the absolute value of the target active power at the grid connection point, thereby restoring the grid connection point voltage to the state before the output active power and the absorbed active power of the inverter are increased.

[0216] For example, Figure 5 As shown in the figure, when the impedance of the grid connection point is inductive and the photovoltaic storage system generates electricity to the grid, the active power of the inverter decreases at t3 and the grid connection point voltage rises, then the reactive power of the inverter can be reduced until the reactive power of the inverter is reduced to 0 and the grid connection point voltage returns to the level before t1.

[0217] For example, Figure 6 As shown in the figure, when the impedance of the grid connection point is inductive and the photovoltaic storage system draws power from the grid, the absorbed active power of the inverter decreases at t3 (the active power of the inverter increases), and the grid connection point voltage rises. The reactive power of the inverter can be reduced until the reactive power of the inverter is reduced to 0, and the grid connection point voltage returns to the level before t1.

[0218] It can be understood that, when the grid connection point impedance is capacitive, after the grid connection point voltage is stabilized at the minimum boundary voltage of the target voltage range or a voltage value greater than the minimum boundary voltage and with a small difference from the minimum boundary voltage based on reducing the reactive power of the inverter, and because the absolute value of the target active power of the grid connection point shows a decreasing trend, that is, the grid connection point voltage shows an increasing trend, the reactive power of the inverter can be increased until it is 0, so that the grid connection point voltage rises based on the decreasing trend of the absolute value of the target active power of the inverter, thereby restoring the grid connection point voltage to the state before the output active power and absorbed active power of the inverter increased.

[0219] For example, Figure 7As shown in the figure, when the impedance of the grid connection point is capacitive and the photovoltaic storage system generates electricity to the grid, the active power of the inverter decreases at t3 and the voltage at the grid connection point increases. The reactive power of the inverter can be increased until the reactive power of the inverter increases to 0 and the voltage at the grid connection point returns to the level before t1.

[0220] For example, Figure 8 As shown in the figure, when the impedance of the grid connection point is capacitive and the photovoltaic storage system draws power from the grid, the absorbed active power of the inverter decreases at t3 (the active power of the inverter increases), and the grid connection point voltage rises. Then, the reactive power of the inverter can be increased until the reactive power of the inverter increases to 0 and the grid connection point voltage returns to the level before t1.

[0221] According to the control method of the photovoltaic storage system provided in the embodiment of the present application, by re-acquiring the target active power of the inverter at at least one acquisition moment, when the impedance category of the grid connection point is inductive and the absolute value of the target active power determined based on at least one newly acquired target active power shows a decreasing trend, the adjustment parameter is reduced to control the grid connection point voltage to increase until the adjustment parameter is reduced to 0; when the impedance category of the grid connection point is capacitive and the absolute value of the target active power determined based on at least one newly acquired target active power shows a decreasing trend, the adjustment parameter is increased to control the grid connection point voltage to increase until the adjustment parameter is reduced to 0. This can achieve the grid connection point voltage rising based on the decreasing trend of the absolute value of the target active power of the inverter, reduce the impact on the increasing trend of the grid connection point voltage, and improve the stability of the photovoltaic storage system.

[0222] In some embodiments, before determining the adjustment parameters based on the adjustment parameters to adjust the inverter based on the type of the grid connection point impedance corresponding to the photovoltaic energy storage system, the method may further include: Obtain the target active power of the grid-connected point at multiple acquisition times; When it is determined that the absolute value of the target active power is increasing based on the target active power at multiple acquisition moments and the grid connection point voltage is not within the target voltage range, the adjustment parameter is determined based on the category.

[0223] In this embodiment, the situation that the absolute value of the target active power presents an increasing trend may include: the absolute value of the target active power at multiple acquisition moments gradually increases or the absolute value of the target active power at multiple acquisition moments fluctuates and increases.

[0224] Based on the target active power at multiple acquisition moments, it is determined that the absolute value of the target active power shows an increasing trend, and then it is judged whether the grid connection point voltage is within the target voltage range. This can reduce the judgment error caused by the sampling error and improve the fault tolerance rate, thereby reducing the subsequent operation frequency of the photovoltaic storage system and improving the stability of the photovoltaic storage system.

[0225] In the actual execution process, the situation in which the absolute value of the target active power determined based on the target active power at multiple collection moments shows an increasing trend, and the grid-connected point voltage is not within the target voltage range can be understood as: based on the target active power at multiple collection moments, it is determined that the grid-connected point voltage shows an increasing or decreasing trend based on the increasing trend of the absolute value of the target active power, and the grid-connected point voltage increases to a value greater than the maximum boundary voltage of the target voltage range or less than the minimum boundary voltage of the target voltage range.

[0226] It can be understood that when the target active power is determined based on multiple acquisition moments and the grid connection point voltage increases to a maximum boundary voltage greater than the target voltage range or less than the minimum boundary voltage of the target voltage range, the adjustment parameters can be determined based on the category of the grid connection point impedance so as to indirectly adjust the grid connection point voltage based on the adjustment parameters later.

[0227] According to the control method of the photovoltaic storage system provided in the embodiment of the present application, by determining that the absolute value of the target active power shows an increasing trend based on the target active power at multiple collection moments and the grid connection point voltage is not within the target voltage range, and then determining the adjustment parameters based on the category of the grid connection point impedance corresponding to the photovoltaic storage system, the judgment error caused by the sampling error can be reduced, and the fault tolerance rate can be improved, thereby reducing the subsequent operation frequency of the photovoltaic storage system and improving the stability of the photovoltaic storage system.

[0228] The following describes how to determine the target voltage range.

[0229] In some embodiments, the target voltage range may be determined based on at least one of an on-grid or off-grid switching over-voltage or under-voltage threshold and category.

[0230] In this embodiment, during the actual implementation, the target voltage range may be directly determined based on the grid-connected and off-grid switching over-voltage and under-voltage thresholds, or may be determined based on the type of grid connection point impedance and the grid-connected and off-grid switching over-voltage and under-voltage thresholds.

[0231] In which, when the target voltage range is determined based on the grid connection point impedance category and the grid-connection and off-grid switching over-voltage and under-voltage thresholds, different grid connection point impedance categories may correspond to different target voltage ranges.

[0232] According to the control method of the photovoltaic storage system provided in the embodiment of the present application, by determining the target voltage range based on at least one of the grid-connected and off-grid switching over-voltage and under-voltage thresholds and the grid-connected point impedance category, multiple methods for determining the target voltage range can be implemented, thereby improving the applicability and feasibility of the target voltage range.

[0233] In some embodiments, the target voltage range is determined based on at least one of the grid-connected and off-grid switching over-voltage and under-voltage thresholds and categories, and may include: In the case where the category is resistive, the first voltage threshold is determined as the maximum boundary value of the target voltage range and the first voltage threshold is less than the grid-connected and off-grid switching overvoltage threshold, and the second voltage threshold is determined as the minimum boundary value of the target voltage range and the second voltage threshold is greater than the grid-connected and off-grid switching undervoltage threshold; In the case where the category is inductive, the second voltage threshold is determined as the minimum boundary value of the target voltage range and the second voltage threshold is greater than the grid-connected and off-grid switching undervoltage threshold; When the category is capacitive, the second voltage threshold is determined as the minimum boundary value of the target voltage range and the second voltage threshold is greater than the grid-connected and off-grid switching undervoltage threshold.

[0234] In this embodiment, the first voltage threshold may be a voltage value that is smaller than the overvoltage threshold and has a small difference from the overvoltage threshold.

[0235] The second voltage threshold may be a voltage value that is greater than the under-voltage threshold and has a smaller difference from the under-voltage threshold.

[0236] The second voltage threshold is smaller than the first voltage threshold.

[0237] It can be understood that when the grid connection point impedance is resistive, the maximum boundary value or the minimum boundary value of the target voltage range can be determined; when the grid connection point impedance is inductive or capacitive, the minimum boundary value of the target voltage range can be determined.

[0238] In the actual implementation process, when the grid connection point impedance is resistive, the grid connection point voltage will rise when the active power of the inverter increases. In order to avoid the disconnection of the grid-connected and off-grid switching switches, the target voltage range may have a maximum boundary value. The first voltage threshold can be determined as the maximum boundary value of the target voltage range; when the active power of the inverter decreases, the grid connection point voltage will drop. In order to avoid the disconnection of the grid-connected and off-grid switching switches, the target voltage range may have a minimum boundary value. The second voltage threshold can be determined as the minimum boundary value of the target voltage range, so as to facilitate the subsequent adjustment of the active power of the inverter, so that when the grid connection point impedance is resistive, the grid connection point voltage is adjusted to be stable within the target voltage range formed by the second voltage threshold and the first voltage range.

[0239] When the impedance of the grid-connected point is inductive or capacitive, the grid-connected point voltage will drop due to the increase or decrease of the active power of the inverter. In order to avoid the disconnection of the grid-connected and off-grid switching switch, the target voltage range may have a minimum boundary value. The second voltage threshold may be determined as the minimum boundary value of the target voltage range, and the maximum boundary value of the target voltage range may be considered to be infinite, so as to facilitate the subsequent adjustment of the reactive power of the inverter, thereby stabilizing the grid-connected point voltage within the target voltage range formed by the second voltage threshold and infinity.

[0240] According to the control method of the photovoltaic storage system provided in the embodiment of the present application, when the grid-connected point impedance is resistive, the first voltage threshold is determined as the maximum boundary value of the target voltage range, and the second voltage threshold is determined as the minimum boundary value of the target voltage range; or when the grid-connected point impedance is inductive or capacitive, the second voltage threshold is determined as the minimum boundary value of the target voltage range. This can achieve the determination of the boundary values ​​of the target voltage range in different scenarios, thereby improving the applicability and feasibility of the target voltage range.

[0241] The control method of the photovoltaic storage system provided in the embodiment of the present application can be executed by a control device of the photovoltaic storage system.

[0242] In the embodiment of the present application, the control device of the photovoltaic storage system executing the control method of the photovoltaic storage system is taken as an example to illustrate the control device of the photovoltaic storage system provided in the embodiment of the present application.

[0243] An embodiment of the present application also provides a control device for a photovoltaic storage system.

[0244] like Fig.12 As shown, the control device of the photovoltaic storage system includes an inverter, and the inverter is respectively connected to the load and the first end of the grid connection point; the first end of the grid connection point is connected to the load and the second end of the grid connection point is connected to the power grid. The control device of the photovoltaic storage system includes: a first processing module 1210 and a second processing module 1220.

[0245] The first processing module 1210 is used to determine the adjustment parameter based on the type of the grid connection point impedance corresponding to the energy storage system when the grid connection point voltage of the grid connection point is not within the target voltage range; the target voltage range is a preset voltage range for keeping the photovoltaic storage system in a grid-connected operation state unchanged; The second processing module 1220 is used to adjust the inverter based on the adjustment parameters so that the adjusted grid-connected point voltage is stabilized within the target voltage range and the switching frequency of the grid-connected and off-grid states of the photovoltaic storage system is reduced.

[0246] According to the control device of the photovoltaic storage system provided in the embodiment of the present application, when the grid connection point voltage at the grid connection point is not within the target voltage range, the adjustment parameters are determined based on the category of the grid connection point impedance corresponding to the photovoltaic storage system, and the inverter is adjusted based on the adjustment parameters to stabilize the adjusted grid connection point voltage within the target voltage range. When the grid connection point generates electricity to the power grid or draws electricity from the power grid, the grid connection point voltage can be indirectly adjusted to be within the target voltage range based on adjusting the inverter, thereby reducing the overvoltage or undervoltage threshold of the grid connection point voltage triggering on-grid and off-grid switching, thereby reducing the frequency of on-grid and off-grid switching, improving the synergy between the photovoltaic storage system and the power grid, and improving the stability and reliability of the photovoltaic storage system.

[0247] In some embodiments, the first processing module 1210 may also be used to: In the case where the category is resistive, the regulation parameter is determined as the active power of the inverter; In the case where the category is inductive, the regulation parameter is determined as the reactive power of the inverter; In the case of the capacitive category, the control variable is determined as the reactive power of the inverter.

[0248] In some embodiments, the second processing module 1220 may also be used to: When the type is resistive and the grid-connected point is in a power generation state, the adjustment parameter is reduced until the adjusted grid-connected point voltage is stabilized within the target voltage range; When the type is resistive and the grid connection point is in the power-taking state, increase the adjustment parameter until the adjusted grid connection point voltage is stable within the target voltage range; In the case of inductive type, increase the adjustment parameter until the adjusted grid connection point voltage is stable within the target voltage range; In the case of capacitive type, the adjustment parameter is reduced until the adjusted grid connection point voltage is stabilized within the target voltage range.

[0249] In some embodiments, the control device of the optical storage system may further include a third processing module, which is used to: After adjusting the inverter based on the adjustment parameters so that the adjusted grid connection point voltage is stabilized within the target voltage range, the target active power of the grid connection point at at least one acquisition time is obtained; When the category is inductive and the absolute value of the target active power determined based on the target active power at at least one acquisition moment shows a decreasing trend, the adjustment parameter is reduced to control the grid connection point voltage to increase until the adjustment parameter is reduced to 0; When the category is capacitive and the absolute value of the target active power determined based on the target active power at at least one acquisition moment shows a decreasing trend, the adjustment parameter is increased to control the grid connection point voltage to increase until the adjustment parameter is reduced to 0.

[0250] In some embodiments, the control device of the optical storage system may further include a fourth processing module, which is used to: Before adjusting the inverter based on the adjustment parameters, the target active power of the grid-connected point at multiple acquisition times is obtained; When it is determined that the absolute value of the target active power is increasing based on the target active power at multiple acquisition moments and the grid connection point voltage is not within the target voltage range, the adjustment parameter is determined based on the category.

[0251] The control device of the optical storage system in the embodiment of the present application may be an electronic device, or a component in the electronic device, such as an integrated circuit or a chip. The electronic device may be a terminal, or other devices other than a terminal.

[0252] The control device of the optical storage system in the embodiment of the present application may be a device having an operating system. The operating system may be an Android operating system, an IOS operating system, or other possible operating systems, which are not specifically limited in the embodiment of the present application.

[0253] The control device of the photovoltaic storage system provided in the embodiment of the present application can achieve Figures 1 to 8 To avoid repetition, the various processes implemented by the method embodiment are not described here.

[0254] The embodiment of the present application also provides a solar storage system.

[0255] like Fig. 9 , Fig.10 or Fig.11 As shown, in this embodiment, the photovoltaic storage system includes: an inverter, an on-grid and off-grid switching device, a photovoltaic module and an energy storage module.

[0256] Among them, the inverter is a device that converts direct current into alternating current.

[0257] In actual implementation, the inverter can convert the direct current generated by the solar panels of the photovoltaic storage system into alternating current to power the load or the grid.

[0258] The load may be electrical equipment in a household or commercial facility.

[0259] The on-grid and off-grid switching device may be an on-grid and off-grid switching switch for switching the on-grid or off-grid state of the grid connection point.

[0260] The inverter is connected to the first end of the on-grid and off-grid switching device.

[0261] The second end of the on-grid and off-grid switching device is connected to the grid connection point.

[0262] Photovoltaic modules can be used to realize photovoltaic power generation based on photovoltaic arrays.

[0263] The energy storage module can be used to store the electricity generated by photovoltaic power generation.

[0264] The photovoltaic storage system operates based on the control method of the photovoltaic storage system described in any of the above embodiments.

[0265] According to the photovoltaic storage system provided in the embodiment of the present application, when the grid connection point voltage at the grid connection point is not within the target voltage range, the adjustment parameters are determined based on the category of the grid connection point impedance corresponding to the photovoltaic storage system, and the inverter is adjusted based on the adjustment parameters to stabilize the adjusted grid connection point voltage within the target voltage range. When the grid connection point generates electricity to the power grid or draws electricity from the power grid, the grid connection point voltage can be indirectly adjusted to be within the target voltage range based on adjusting the inverter, thereby reducing the overvoltage or undervoltage threshold of the grid connection point voltage triggering on-grid and off-grid switching, thereby reducing the frequency of on-grid and off-grid switching, improving the synergy between the photovoltaic storage system and the power grid, and improving the stability and reliability of the photovoltaic storage system.

[0266] In some embodiments, Fig.13 As shown, an embodiment of the present application also provides an electronic device 1300, including a processor 1301, a memory 1302, and a computer program stored in the memory 1302 and executable on the processor 1301. When the program is executed by the processor 1301, each process of the control method embodiment of the above-mentioned optical storage system is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0267] It should be noted that the electronic devices in the embodiments of the present application include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0268] An embodiment of the present application also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various processes of the control method embodiment of the above-mentioned optical storage system are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0269] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0270] An embodiment of the present application further provides a computer program product, including a computer program, which implements the control method of the above-mentioned optical storage system when executed by a processor.

[0271] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0272] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned control method embodiment of the optical storage system, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0273] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0274] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0275] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the relevant technology, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, disk, CD), and includes a number of instructions for a terminal (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0276] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

[0277] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means 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 application. In this specification, the schematic representation of the above terms does not necessarily refer 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.

[0278] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A control method for a photovoltaic storage system, characterized in that: The photovoltaic storage system comprises an inverter and an on-grid and off-grid switching device, wherein the inverter is connected to a first end of the on-grid and off-grid switching device; and a second end of the on-grid and off-grid switching device is connected to a grid connection point; There is impedance between the grid connection point and the power grid; the method comprises: When the grid connection point voltage of the grid connection point is not within the target voltage range, the adjustment parameter is determined based on the type of grid connection point impedance corresponding to the photovoltaic storage system; the target voltage range is a preset voltage range for keeping the photovoltaic storage system in a grid-connected operation state; The inverter is adjusted based on the adjustment parameters so that the adjusted grid-connected point voltage is stabilized within the target voltage range, thereby reducing the switching frequency of the grid-connected and off-grid states of the photovoltaic storage system.

2. The control method of the photovoltaic storage system according to claim 1, characterized in that: The target voltage range is determined based on the grid-connected and off-grid switching over-voltage and under-voltage thresholds and at least one of the categories; the grid-connected and off-grid switching over-voltage and under-voltage thresholds include the grid-connected and off-grid switching under-voltage threshold and the grid-connected and off-grid switching over-voltage threshold; the categories include resistive, inductive and capacitive.

3. The control method of the photovoltaic storage system according to claim 2, characterized in that: The target voltage range is determined based on the grid-connected and off-grid switching over-voltage and under-voltage thresholds and at least one of the categories, including: In the case where the category is resistive, the first voltage threshold is determined as the maximum boundary value of the target voltage range and the first voltage threshold is less than the grid-connected and off-grid switching overvoltage threshold, and the second voltage threshold is determined as the minimum boundary value of the target voltage range and the second voltage threshold is greater than the grid-connected and off-grid switching undervoltage threshold; In the case where the category is inductive, the second voltage threshold is determined as the minimum boundary value of the target voltage range and the second voltage threshold is greater than the grid-connected and off-grid switching undervoltage threshold; When the category is capacitive, the second voltage threshold is determined as the minimum boundary value of the target voltage range and the second voltage threshold is greater than the on-grid and off-grid switching undervoltage threshold, wherein the second voltage threshold is less than the first voltage threshold.

4. The control method of the photovoltaic storage system according to any one of claims 1 to 3, characterized in that: The determining of the adjustment parameters based on the type of the grid connection point impedance corresponding to the photovoltaic storage system includes: In the case where the category is resistive, determining the adjustment parameter as the active power of the inverter; In the case where the category is inductive, determining the adjustment parameter as the reactive power of the inverter; When the category is capacitive, the regulating parameter is determined as the reactive power of the inverter.

5. The control method of the photovoltaic storage system according to any one of claims 1 to 3, characterized in that: The step of adjusting the inverter based on the adjustment parameter so that the adjusted grid connection point voltage is stabilized within the target voltage range includes: When the category is resistive and the grid-connected point is in a power generation state, reducing the adjustment parameter until the adjusted grid-connected point voltage is stabilized within the target voltage range; When the category is resistive and the grid-connected point is in a power-taking state, increasing the adjustment parameter until the adjusted grid-connected point voltage is stabilized within the target voltage range; In the case where the category is inductive, increasing the adjustment parameter until the adjusted grid connection point voltage is stabilized within the target voltage range; When the category is capacitive, the adjustment parameter is reduced until the adjusted grid connection point voltage is stabilized within the target voltage range.

6. The control method of the photovoltaic storage system according to any one of claims 1 to 3, characterized in that: After adjusting the inverter based on the adjustment parameter so that the adjusted grid connection point voltage is stabilized within the target voltage range, the method further includes: Obtaining the target active power of the grid-connected point at at least one collection moment; When the category is inductive and the absolute value of the target active power determined based on the target active power at the at least one acquisition moment shows a decreasing trend, reducing the adjustment parameter to control the grid connection point voltage to increase until the adjustment parameter is reduced to 0; When the category is capacitive and the absolute value of the target active power determined based on the target active power at at least one acquisition moment shows a decreasing trend, the adjustment parameter is increased to control the grid connection point voltage to increase until the adjustment parameter is reduced to 0.

7. The control method of the photovoltaic storage system according to any one of claims 1 to 3, characterized in that: Before adjusting the inverter based on the adjustment parameter, the method further includes: Obtaining the target active power of the grid-connected point at multiple collection moments; When it is determined based on the target active powers at the multiple acquisition moments that the absolute value of the target active power shows an increasing trend and the grid connection point voltage is not within the target voltage range, an adjustment parameter is determined based on the category.

8. A control device for a photovoltaic storage system, characterized in that: The photovoltaic storage system comprises an inverter and an on-grid and off-grid switching device, wherein the inverter is connected to a first end of the on-grid and off-grid switching device; and a second end of the on-grid and off-grid switching device is connected to a grid connection point; There is impedance between the grid connection point and the power grid; the device comprises: A first processing module is used to determine the adjustment parameter based on the type of the grid connection point impedance corresponding to the photovoltaic storage system when the grid connection point voltage of the grid connection point is not within the target voltage range; the target voltage range is a preset voltage range for keeping the photovoltaic storage system in a grid-connected operation state unchanged; The second processing module is used to adjust the inverter based on the adjustment parameters so that the adjusted grid-connected point voltage is stabilized within the target voltage range, thereby reducing the switching frequency of the grid-connected and off-grid states of the photovoltaic storage system.

9. A solar energy storage system, characterized in that: include: An inverter connected to a first end of the on-grid and off-grid switching device; A grid-connected switching device, wherein the second end of the grid-connected switching device is connected to the grid connection point; A photovoltaic module, wherein the photovoltaic module is connected to the inverter; An energy storage module, wherein the energy storage module is connected to the inverter; The photovoltaic storage system operates based on the photovoltaic storage system control method according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the control method of the photovoltaic storage system as described in any one of claims 1 to 7 is implemented.

11. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the control method of the photovoltaic storage system as described in any one of claims 1 to 7 is implemented.

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