Control method for energy storage coupling system

Abstract

A control method for an energy storage coupling system. The energy storage coupling system comprises a switching apparatus, wherein one end of the switching apparatus is connected to an energy storage system and a photovoltaic system, and the other end of the switching apparatus is connected to a power grid and an electric load; and the switching apparatus at least comprises a first branch and a second branch that are connected in parallel, the first branch being provided with at least one first mechanical switch, and the second branch being provided with at least one first semiconductor switch. The method comprises: where an energy storage coupling system operates in an off-grid mode, and when it is detected that a grid connection condition is satisfied, controlling a second branch to switch to an on state; and when it is detected that the difference in voltage across a switching apparatus is less than a preset voltage threshold value, controlling a first branch to switch to an on state.

Description

Control methods for energy storage coupled systems

[0001] Cross-reference to related applications

[0002] This application is based on and claims priority to Chinese Patent Application No. 2024108431362, filed on June 26, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a control method for an energy storage coupling system, the energy storage coupling system, and an inverter device. Background Technology

[0004] In an energy storage coupling system, the energy storage system and the photovoltaic system can be used in conjunction with the power grid to supply power to electrical loads. As shown in Figure 2, the energy storage coupling system is usually equipped with a switching switch, namely K2 in Figure 2. The switching switch K2 enables the energy storage system and the photovoltaic system to be connected to or disconnected from the power grid. When the power grid supply is normal, the switching switch K2 is closed, and the energy storage system and the photovoltaic system can be connected to the power grid and supply power to electrical loads in conjunction with the power grid, and can also transmit electrical energy to the power grid; when the power grid supply is abnormal, the switching switch K2 is open, and the energy storage system and the photovoltaic system are disconnected from the power grid.

[0005] When the energy storage system and photovoltaic system cannot meet the load power demand, the system switches from off-grid mode to grid-connected mode, using the grid to output power to supply the load. At the moment the switching switch closes, the current passing through it may change from 0 to a large value instantaneously. Similarly, when the system switches from grid-connected mode to off-grid mode, the current may suddenly drop to 0 at the moment the switching switch opens.

[0006] During the off-grid and grid-connection switching process, the instantaneous current of the switching switch changes greatly, which can cause problems such as arcing and high power consumption of the switching switch, thereby affecting the safety and efficiency of the off-grid and grid-connection process.

[0007] Summary of the Invention

[0008] This disclosure aims to address at least one of the technical problems existing in the prior art. To this end, this disclosure proposes a control method for an energy storage coupling system, an energy storage coupling system, and an inverter device, which can ensure the smoothness and safety of the grid-connected switching process of the energy storage coupling system, and has low power consumption.

[0009] This disclosure provides a control method for an energy storage coupling system. The energy storage coupling system includes a switching device, one end of which is connected to the energy storage system and a photovoltaic system, and the other end of which is connected to the power grid and an electrical load. The switching device includes at least a first branch and a second branch connected in parallel. The first branch is equipped with at least one first mechanical switch, and the second branch is equipped with at least one first semiconductor switch. The method includes:

[0010] When the energy storage coupling system is operating in off-grid mode, and the grid connection conditions are detected, the second branch is controlled to switch to the on state.

[0011] When the voltage difference across the switching device is detected to be less than a preset voltage threshold, the first branch is controlled to switch to the conducting state.

[0012] According to one embodiment of this disclosure, the method further includes:

[0013] When the energy storage coupling system is operating in grid-connected mode and both the first branch and the second branch are in the conducting state, when the off-grid conditions are detected, the first branch and the second branch are controlled to switch to the disconnected state to disconnect from the power grid.

[0014] According to one embodiment of this disclosure, controlling the first branch and the second branch to switch to an off state includes:

[0015] First, control the first branch to switch to the disconnected state, and then control the second branch to switch to the disconnected state.

[0016] According to one embodiment of this disclosure, the second branch further includes a second mechanical switch connected in series with the first semiconductor switch. The step of first controlling the first branch to switch to an open state, and then controlling the second branch to switch to an open state, includes:

[0017] First, control the first mechanical switch of the first branch to open, so that the first branch is switched to the open state;

[0018] Then, control the first semiconductor switch of the second branch to turn off. If the current of the second branch is less than the branch current threshold, control the second mechanical switch of the second branch to open, so that the second branch switches to the open state.

[0019] According to one embodiment of this disclosure, the method further includes:

[0020] When the energy storage coupling system is operating in grid-connected mode, with the first branch in the on state and the second branch in the off state, when the off-grid conditions are detected, the system first controls the second branch to switch to the on state, then controls the first branch to switch to the off state, and then controls the second branch to switch to the off state again, so as to disconnect the connection with the power grid.

[0021] According to one embodiment of this disclosure, the second branch further includes a second mechanical switch connected in series with the first semiconductor switch. When the energy storage coupling system is operating in off-grid mode, and grid connection conditions are detected, the second branch is controlled to switch to the on state, including:

[0022] First, control the second mechanical switch of the second branch to close, and then control the first semiconductor switch of the second branch to turn on, so that the second branch switches to the on state.

[0023] According to one embodiment of this disclosure, after controlling the first branch to switch to the on state, the method further includes:

[0024] Control the second branch to switch to the disconnected state.

[0025] According to one embodiment of this disclosure, detecting the voltage difference across the switching device includes:

[0026] Collect the first voltage value at one end of the switching device and the second voltage value at the other end of the switching device;

[0027] The first voltage value and the second voltage value are compared to determine the voltage difference.

[0028] This disclosure provides an energy storage coupling system, including:

[0029] A switching device, one end of which is connected to an energy storage system and a photovoltaic system, and the other end of which is connected to a power grid and an electrical load. The switching device includes at least a first branch and a second branch connected in parallel. The first branch is provided with at least one first mechanical switch, and the second branch is provided with at least one first semiconductor switch.

[0030] A first controller, connected to the switching device, is configured to execute the control method of the energy storage coupling system described in the first aspect above.

[0031] According to one embodiment of this disclosure, the energy storage coupling system further includes:

[0032] Multiple inverters are connected in parallel to one end of the switching device. The inverters are configured to transform the output current of the energy storage system or the output current of the photovoltaic system.

[0033] This disclosure provides an inverter device, including:

[0034] Inverter module;

[0035] The switching device is provided, wherein the input terminal of the inverter module is connected to an energy storage system or a photovoltaic system, and the output terminal of the inverter module is connected to the power grid and the electrical load through the switching device. The switching device includes at least a first branch and a second branch connected in parallel. The first branch is provided with at least one first mechanical switch, and the second branch is provided with at least one first semiconductor switch.

[0036] A second controller, connected to the switching device, is configured to execute the control method of the energy storage coupling system described in the first aspect above.

[0037] This disclosure provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the control method of the energy storage coupling system as described in the first aspect above.

[0038] This disclosure provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the control method for the energy storage coupling system as described in the first aspect above.

[0039] This disclosure provides a computer program product, including a computer program that, when executed by a processor, implements the control method for the energy storage coupling system as described in the first aspect above.

[0040] The above-described one or more technical solutions in this disclosure have at least the following technical effects: By connecting the first mechanical switch and the first semiconductor switch in parallel in the switching device, with one end of the switching device connected to the energy storage system and the photovoltaic system, and the other end connected to the power grid, when the power grid supply is normal, the first semiconductor switch is first controlled to conduct. After the voltage difference across the first mechanical switch decreases to a voltage difference that the first mechanical switch can withstand when it is closed, the first mechanical switch is then closed. This avoids arcing caused by the first mechanical switch being subjected to an excessively large voltage difference, thereby preventing damage and ensuring the safe operation of the grid-connected switching device. Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure.

[0041] Brief description of the attached figures

[0042] The above and / or additional aspects and advantages of this disclosure will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0043] Figure 1 is a flowchart illustrating the control method of the energy storage coupling system provided in an embodiment of this disclosure;

[0044] Figure 2 is a schematic diagram of the energy storage coupling system in the related technology;

[0045] Figure 3 is one of the structural schematic diagrams of the energy storage coupling system provided in the embodiments of this disclosure;

[0046] Figure 4 is a schematic diagram of one of the switching devices provided in an embodiment of this disclosure;

[0047] Figure 5 is a second schematic diagram of the switching device provided in an embodiment of this disclosure;

[0048] Figure 6 is a second schematic diagram of the energy storage coupling system provided in an embodiment of this disclosure;

[0049] Figure 7 is a schematic diagram of the inverter device provided in an embodiment of this disclosure;

[0050] Figure 8 is a schematic diagram of the structure of the electronic device provided in an embodiment of this disclosure.

[0051] Reference numerals: Energy storage coupling system 200, Energy storage system 210, Photovoltaic system 220, Power grid 400, Switching device 300, First branch 310, Second branch 320, First mechanical switch 330, First semiconductor switch 340, First terminal 350, Second terminal 360, Second mechanical switch 370, Electrical load 500, First controller 230, Inverter 240, Inverter module 241, Second controller 242. Detailed Implementation

[0052] The technical solutions of the embodiments of this disclosure will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure are within the scope of protection of this disclosure.

[0053] The terms "first," "second," etc., used in this disclosure are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this disclosure can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., can be of the same class, without limiting the number of objects; for example, a first object can be one or more. Furthermore, in this disclosure, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects have an "or" relationship.

[0054] The control method, energy storage coupling system 200, inverter device 240, electronic equipment and readable storage medium of the energy storage coupling system 200 provided in this disclosure will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0055] The control method of the energy storage coupling system 200 can be applied to the terminal, and can be executed by the hardware or software in the terminal.

[0056] The terminal includes, but is not limited to, portable communication devices such as mobile phones or tablets with touch-sensitive surfaces (e.g., touchscreen displays and / or touchpads). It should also be understood that, in some embodiments, the terminal may not be a portable communication device, but rather a desktop computer with touch-sensitive surfaces (e.g., touchscreen displays and / or touchpads).

[0057] The following embodiments describe a terminal including a display and a touch-sensitive surface. However, it should be understood that the terminal may include one or more other physical user interface devices such as a physical keyboard, mouse, and joystick.

[0058] The control method for the energy storage coupling system 200 provided in this embodiment can be executed by an electronic device or a functional module or entity in an electronic device that can implement the control method for the energy storage coupling system 200.

[0059] In other words, the control method of the energy storage coupling system 200 provided in the embodiments of this disclosure can be executed in an electronic device, or the control method of the energy storage coupling system 200 provided in the embodiments of this disclosure can also be executed in a functional module or functional entity in an electronic device.

[0060] The electronic devices mentioned in the embodiments of this disclosure include, but are not limited to, mobile phones, tablets, computers, cameras, and wearable devices. The control method of the energy storage coupling system 200 provided in the embodiments of this disclosure will be described below using an electronic device as the execution subject.

[0061] As shown in Figure 3, the energy storage coupling system 200 includes a switching device 300. One end of the switching device 300 is connected to the energy storage system 210 and the photovoltaic system 220, and the other end of the switching device 300 is connected to the power grid 400 and the electrical load 500.

[0062] Among them, the energy storage coupling system 200 is a system that can transmit the electrical energy stored in the energy storage system 210 and the electrical energy converted from solar energy by the photovoltaic system 220 to the power grid 400 or the electrical load 500.

[0063] Energy storage system 210 is a system that can store electrical energy, and photovoltaic system 220 is a system that can convert solar energy into electrical energy.

[0064] The switching device 300 of this embodiment has two ends that can be connected to other devices, including a first end 350 and a second end 360. The first end 350 is connected to the energy storage system 210 and the photovoltaic system 220, and the second end 360 is connected to the power grid 400 and the electrical load 500.

[0065] In this embodiment, the first end 350 of the switching device 300 can be an input end, and the second end 360 of the switching device 300 can be an output end. The energy storage system 210 and the photovoltaic system 220 can be connected to the power grid 400 through the switching device 300.

[0066] When the switching device 300 is turned on, the energy storage system 210 and the photovoltaic system 220 can be connected to the grid 400. That is, the electrical energy output by the energy storage system 210 and the photovoltaic system 220 can be transmitted to the grid 400 through the switching device 300, and the grid 400 can supply power to the electrical load together with the energy storage system 210 and the photovoltaic system 220.

[0067] When the switching device 300 is disconnected, the energy storage system 210 and the photovoltaic system 220 can be disconnected from the power grid 400, that is, the energy storage system 210 and the photovoltaic system 220 are disconnected from the power grid 400, and the electricity output by the energy storage system 210 and the photovoltaic system 220 cannot be transmitted to the power grid 400.

[0068] In this embodiment, as shown in FIG4, the switching device 300 includes at least a first branch 310 and a second branch 320 connected in parallel. The first branch 310 is provided with at least one first mechanical switch 330, and the second branch 320 is provided with at least one first semiconductor switch 340.

[0069] The first mechanical switch 330 is a switching device that controls the connection or disconnection of the circuit through physical contact or physical separation of the control components.

[0070] The first mechanical switch 330 may include a component that switches between physical contact and physical separation, wherein the circuit is connected when the component achieves physical contact and disconnected when the component achieves physical separation.

[0071] For example, the first mechanical switch 330 can be a contactor, a controllable circuit breaker, an electric switch, etc.

[0072] In this embodiment, the first mechanical switch 330 may also have a manual operation interface, such as a button or a handle, which can provide emergency manual closing or opening operation when the power supply device of the first mechanical switch 330 or the control command of the first mechanical switch 330 fails.

[0073] In this embodiment, the first semiconductor switch 340 is a switch that uses the conduction and cutoff characteristics of semiconductor devices to realize the switching on and off of the circuit.

[0074] The first semiconductor switch 340 can be a power semiconductor device, such as an insulated gate bipolar transistor, a metal-oxide-semiconductor field-effect transistor, or a thyristor.

[0075] In this embodiment, the first semiconductor switch 340 can be a single power semiconductor device or two power semiconductor devices connected in reverse parallel.

[0076] In this embodiment, multiple mechanical switches connected in series can be provided in the first branch 310. When all mechanical switches in the first branch 310 are closed, the first branch 310 is in the on state. When any mechanical switch in the first branch 310 is open, the first branch 310 is in the off state.

[0077] The second branch 320 may be equipped with a first semiconductor switch 340 and multiple mechanical switches. When all the mechanical switches in the second branch 320 are closed and the first semiconductor switch 340 is turned on, the second branch 320 is in the on state. When a mechanical switch in the second branch 320 is turned off or the first semiconductor switch 340 is turned off, the second branch 320 is in the off state.

[0078] It is understandable that when both the first branch 310 and the second branch 320 are in the open state, the switching device 300 is disconnected; when both the first branch 310 and the second branch 320 are in the connected state, the switching device 300 is connected.

[0079] In this embodiment, the switching device 300 can have a visible on / off state, that is, the operator can determine whether the switching device 300 is in the on or off state by observing the switching device 300.

[0080] In this embodiment, the switching device 300 can be powered by the connected energy storage system 210 and photovoltaic system 220, or by other power supply devices, thereby realizing the switching of on and off states. The power supply method can be bilateral power supply or unilateral power supply.

[0081] In this embodiment, the switching device 300 may include an instruction receiving device, which can acquire instructions to control the on / off state and switching sequence of the switching device 300.

[0082] In actual operation, the command receiving device can obtain control commands through wired communication such as dry contacts and RS485, or wireless communication such as WiFi.

[0083] The control method of the energy storage coupling system 200 in this embodiment is used to control the energy storage system 210 and photovoltaic system 220 of the energy storage coupling system 200 to be connected to the grid 400 or disconnected from the grid 400 by controlling the on / off state of the switching device 300 in the energy storage coupling system 200.

[0084] The following example illustrates the control method of the energy storage coupling system 200 disclosed herein, using the example of a first mechanical switch 330 installed in the first branch 310 and a first semiconductor switch 340 installed in the second branch 320 of the switching device 300.

[0085] As shown in Figure 1, the control method of the energy storage coupling system 200 includes steps 110 and 120.

[0086] Step 110: When the energy storage coupling system 200 is operating in off-grid mode, and the grid connection conditions are detected, control the second branch 200 to switch to the on state.

[0087] In this step, a grid 400 monitoring device can be installed in the energy storage coupling system 200 to monitor the output voltage and output power of the grid 400, thereby determining whether the power supply is normal.

[0088] In this embodiment, the energy storage coupling system 200 operates in off-grid mode when both branches of the switching device 300 are disconnected.

[0089] When the first branch 310 is in the open state, the electrical power of the energy storage system 210 and the photovoltaic system 220 cannot be transmitted in the first branch 310. When the first mechanical switch 330 is open, the first branch 310 is in the open state.

[0090] When the second branch 320 is in the off state, the electrical power of the energy storage system 210 and the photovoltaic system 220 cannot be transmitted in the second branch 320. When the first semiconductor switch 340 is turned off, the second branch 320 is in the off state.

[0091] In this embodiment, the power grid 400 is supplying power normally, meeting the conditions for the energy storage system 210 and the photovoltaic system 220 to be connected to the power grid 400. When both branches of the switching device 300 are in the disconnected state, the energy storage system 210 and the photovoltaic system 220 are not connected to the power grid 400. The switching device 300 can be controlled to be turned on so that the energy storage system 210 and the photovoltaic system 220 can be connected to the power grid 400.

[0092] In this step, after the first semiconductor switch 340 of the second branch 320 is turned on, the second branch 320 is in the conducting state, the circuit between the energy storage system 210 and the photovoltaic system 220 and the power grid 400 is connected, and the current output by the energy storage system 210 and the photovoltaic system 220 can be transmitted to the power grid 400 through the second branch 320.

[0093] In this embodiment, as the current output from the energy storage system 210 and the photovoltaic system 220 passes through the second branch 320 and is transmitted to the power grid 400, the voltage difference between the first terminal 350 and the second terminal 360 of the switching device 300 continuously decreases.

[0094] Step 120: When the voltage difference across the switching device 300 is less than a preset voltage threshold, control the first branch 310 to switch to the on state.

[0095] The preset voltage threshold is the voltage value that the first mechanical switch 330 can withstand when it is closed, and the preset voltage threshold is less than the maximum voltage value that the first mechanical switch 330 can withstand when it is closed.

[0096] For example, if the maximum voltage that the first mechanical switch 330 can withstand when closed is 5V, the preset voltage threshold can be set to 2V.

[0097] It is understandable that the voltage across the first mechanical switch 330 can be equal to the voltage difference between the first terminal 350 and the second terminal 360 of the switching device 300.

[0098] In this step, the voltage across the switching device 300 can be detected in real time by a voltage detection device, and the detected voltage is output to the controller. The controller calculates the detected voltage to determine whether the voltage difference across the switching device 300 is less than a preset voltage threshold.

[0099] In this embodiment, the first mechanical switch 330 is closed only after the voltage across the first mechanical switch 330 reaches the voltage value that the first mechanical switch 330 can withstand when it is closed. This can prevent the first mechanical switch 330 from arcing due to excessive voltage and being damaged.

[0100] In this step, after the first mechanical switch 330 of the first branch 310 is closed, the first branch 310 is in the connected state, and the current output by the energy storage system 210 and the photovoltaic system 220 can be transmitted stably to the power grid 400 through the first branch 310.

[0101] In this embodiment, when the grid connection conditions are met, the second branch 200 is controlled to switch to the conducting state. After the voltage difference between the two ends of the switching device 300 is less than the preset voltage threshold, the first branch 310 is then controlled to switch to the conducting state, which can realize seamless switching between off-grid and grid-connected.

[0102] Typically, as shown in Figure 2, an energy storage coupling system is equipped with a switching switch, namely K2 in Figure 2. The switching switch K2 enables the energy storage system and the photovoltaic system to be connected to or disconnected from the grid. When the grid power supply is normal, the switching switch K2 is closed, and the energy storage system and the photovoltaic system can be connected to the grid and supply power to the electrical loads together with the grid, and can also transmit electrical energy to the grid. When the grid power supply is abnormal, the switching switch K2 is open, and the energy storage system and the photovoltaic system are disconnected from the grid.

[0103] By using a separate mechanical switch as a switching device, the energy storage system is connected to the grid by closing the mechanical switch. At the instant the mechanical switch closes, the current passing through it may change from 0 to a large value. The large change in current of the mechanical switch and the large voltage value across the mechanical switch can cause arcing and damage to the mechanical switch.

[0104] According to the control method of the energy storage coupling system 200 provided in the embodiments of this disclosure, the first mechanical switch 330 and the first semiconductor switch 340 in the switching device 300 are connected in parallel. One end of the switching device 300 is connected to the energy storage system 210 and the photovoltaic system 220, and the other end is connected to the power grid 400. When the power grid 400 supplies power normally, the first semiconductor switch 340 is first controlled to be turned on. After the voltage difference across the first mechanical switch 330 is reduced to the voltage difference that the first mechanical switch 330 can withstand when it is closed, the first mechanical switch 330 is then closed. This can prevent the first mechanical switch 330 from arcing due to the excessive voltage difference it withstands, thereby causing damage and ensuring the safe operation of the switching device 300.

[0105] In some embodiments, the method further includes:

[0106] When the energy storage coupling system 200 is operating in grid-connected mode and both the first branch 310 and the second branch 320 are in the conducting state, when the off-grid conditions are detected, the first branch 310 and the second branch 320 are controlled to switch to the disconnected state to disconnect from the grid 400.

[0107] It is understandable that when the energy storage coupling system 200 is in grid-connected mode, it can be in a state where the first branch 310 is connected and the second branch 320 is disconnected, or both the first branch 310 and the second branch 320 are connected.

[0108] In this embodiment, the energy storage coupling system 200 operates in grid-connected mode, and both the first branch 310 and the second branch 320 are in a conducting state.

[0109] Switching the state of the first branch 310 and the second branch 320, ultimately disconnecting both the first branch 310 and the second branch 320, allows the energy storage system 210 and the photovoltaic system 220 to be disconnected from the power grid 400, and the energy storage system 210 and the photovoltaic system 220 can supply power to the electrical load 500 independently.

[0110] In this embodiment, when the power supply to the grid 400 is abnormal or the energy storage system 210 is under maintenance or upgrade, the off-grid conditions can be determined, and the energy storage system 210 and the photovoltaic system 220 can be disconnected from the grid 400.

[0111] In this embodiment, a monitoring device for the power grid 400 can be installed in the energy storage coupling system 200 to monitor the output voltage, output power, etc. of the power grid 400, thereby determining whether there is a power supply abnormality.

[0112] In this embodiment, when the power supply of the grid 400 is abnormal or the energy storage system 210 is under maintenance or upgrade, the first branch 310 and the second branch 320 are switched to the disconnected state to disconnect the connection with the grid 400, which can prevent the spread of faults between the energy storage system 210 and the photovoltaic system 220 and the grid 400.

[0113] In some embodiments, controlling the first branch 310 and the second branch 320 to switch to an off state includes:

[0114] First, the first branch 310 is switched to the disconnected state, and then the second branch 320 is switched to the disconnected state. In this embodiment, after the first branch 310 is disconnected, the current output by the energy storage system 210 and the photovoltaic system 220 can pass through the second branch 320 and be transmitted to the power grid 400. During the disconnection of the first branch 310, the voltage difference across the switching device 300 can be maintained at a value close to 0.

[0115] It is understandable that the voltage difference across the first mechanical switch 330 can be equal to the voltage difference across the switching device 300.

[0116] Typically, a separate mechanical switch is used as a switching switch to disconnect the energy storage system from the grid. At the moment the mechanical switch is disconnected, the current of the mechanical switch changes greatly, and the voltage difference across the mechanical switch is large, which can cause arcing and damage to the mechanical switch.

[0117] In this embodiment, the voltage difference between the two ends of the first mechanical switch 330 does not change significantly before and after the first mechanical switch 330 is disconnected, and is close to 0. This can prevent the voltage difference from being too large at the moment the first mechanical switch 330 is disconnected, which could cause arcing and damage, and ensure the safe operation of the switching device 300.

[0118] In this embodiment, after the first mechanical switch 330 is opened, the first semiconductor switch 340 is then turned off, and both the first branch 310 and the second branch 320 are switched to the open state, and the energy storage system 210 and the photovoltaic system 220 are disconnected from the power grid 400.

[0119] In some embodiments, as shown in FIG5, the second branch 320 is further provided with a second mechanical switch 370 connected in series with the first semiconductor switch 340, which first controls the first branch 310 to switch to the off state, and then controls the second branch 320 to switch to the off state, including:

[0120] First, control the first mechanical switch 330 of the first branch 310 to open, so that the first branch 310 is switched to the open state;

[0121] Then, the first semiconductor switch 340 of the second branch 320 is turned off. When the current of the second branch 320 is less than the branch current threshold, the second mechanical switch 370 of the second branch 320 is turned off, so that the second branch 320 is switched to the off state.

[0122] The second mechanical switch 370 may include a component that switches between physical contact and physical separation. When the component makes physical contact, the circuit is connected, and when the component makes physical separation, the circuit is disconnected.

[0123] For example, the second mechanical switch 370 can be a contactor, a controllable circuit breaker, an electric switch, etc.

[0124] In this embodiment, the second mechanical switch 370 can be located on the side near the second end 360, that is, the current first passes through the first semiconductor switch 340 and then through the second mechanical switch 370.

[0125] In this embodiment, the second mechanical switch 370 is connected in series with the first semiconductor switch 340. The second mechanical switch 370 can realize more flexible circuit switching. For example, if the first semiconductor switch 340 is faulty, the connection of the second branch 320 can be disconnected by the second mechanical switch 370.

[0126] In this embodiment, the branch current threshold is the maximum current that the second mechanical switch 370 can withstand when the state is switched.

[0127] In this embodiment, when the second branch 320 is disconnected, the first semiconductor switch 340 of the second branch 320 is first turned off. After the current of the second branch 320 is less than the branch current threshold, the second mechanical switch 370 is then disconnected. This can avoid arcing at the moment the second mechanical switch 370 is disconnected and prevent damage to the second mechanical switch 370.

[0128] In some embodiments, the control method for the energy storage coupling system 200 further includes:

[0129] When the energy storage coupling system 200 is operating in grid-connected mode, with the first branch 310 in the conducting state and the second branch 320 in the disconnected state, when the off-grid conditions are detected, the system first controls the second branch 320 to switch to the conducting state, then controls the first branch 310 to switch to the disconnected state, and then controls the second branch 320 to switch to the disconnected state, so as to disconnect the connection with the power grid.

[0130] In this embodiment, the first branch 310 is turned on and the second branch 320 is turned off. In order to disconnect the energy storage system 210 and the photovoltaic system 220 from the power grid 400, the first branch 310 is also turned off. Before turning off the first branch 310, the second branch 320 is turned on.

[0131] Understandably, after the first semiconductor switch 340 of the second branch 320 is turned on, the second branch 320 is in the connected state, and the current output by the energy storage system 210 and the photovoltaic system 220 can pass through the second branch 320 and be transmitted to the power grid 400.

[0132] In this embodiment, after the first branch 310 is disconnected, the current output by the energy storage system 210 and the photovoltaic system 220 can be transmitted to the power grid 400 through the second branch 320. During the disconnection of the first branch 310, the voltage difference across the switching device 300 can be kept close to 0.

[0133] It is understandable that the voltage difference across the first mechanical switch 330 can be equal to the voltage difference across the switching device 300.

[0134] In this embodiment, after controlling the first branch 310 to switch to the disconnected state, the first semiconductor switch 340 of the second branch 320 is then controlled to turn off, thereby disconnecting the connection with the power grid.

[0135] In this embodiment, the second branch 320 is first switched to the conducting state, then the first branch 310 is switched to the disconnected state, and then the second branch 320 is switched to the disconnected state. This can avoid the voltage difference being too large at the moment the first mechanical switch 330 is disconnected, which could cause arcing and damage. This can safely disconnect the energy storage system 210 and the photovoltaic system 220 from the grid 400.

[0136] In some embodiments, the second branch 320 further includes a second mechanical switch 370 connected in series with the first semiconductor switch 340. When the energy storage coupling system 200 is operating in off-grid mode, and grid connection conditions are detected, the second branch 320 is controlled to switch to the on state, including:

[0137] First, control the second mechanical switch 370 of the second branch 320 to close, and then control the first semiconductor switch 340 of the second branch 320 to turn on, so that the second branch 320 switches to the on state.

[0138] In this embodiment, when controlling the second branch 320 to conduct, the second mechanical switch 370 is first controlled to close, and then the first semiconductor switch 340 is controlled to conduct. At the moment the second mechanical switch 370 closes, no current flows through the second branch 320, which can avoid arcing at the moment the second mechanical switch 370 closes and prevent damage to the second mechanical switch 370.

[0139] In some embodiments, after controlling the first branch 310 to switch to the on state, the method further includes:

[0140] Control the second branch 320 to switch to the disconnected state.

[0141] In this embodiment, after the first mechanical switch 330 of the first branch 310 is closed, the first branch 310 is in the on state, and the current output by the energy storage system 210 and the photovoltaic system 220 can pass through the first branch 310 and be stably transmitted to the power grid 400.

[0142] In related technologies, when the switching switch is a semiconductor switch, the semiconductor switch will suffer from problems such as high losses and low system efficiency when it is turned on for a long time.

[0143] In this embodiment, after the first mechanical switch 330 of the first branch 310 is closed, putting the first branch 310 in the on state, the first semiconductor switch 340 of the second branch 320 can be turned off, avoiding power loss and device loss caused by the long-term conduction of the first semiconductor switch 340, thereby improving the power transmission efficiency of the system.

[0144] In some embodiments, detecting the voltage difference across the switching device 300 includes:

[0145] The first voltage value at one end of the switching device 300 and the second voltage value at the other end of the switching device 300 are collected.

[0146] The first voltage value and the second voltage value are compared to determine the voltage difference.

[0147] The first voltage value can be the voltage value of the first terminal 350 of the switching device 300, and the second voltage value can be the voltage value of the second terminal 360 of the switching device 300.

[0148] In this embodiment, the first voltage value and the second voltage value at both ends of the switching device 300 can be detected in real time by the voltage detection device, and the detected first voltage value and the second voltage value are output to the comparison unit of the controller. The comparison unit compares the first voltage value and the second voltage value and calculates the difference to determine the voltage difference.

[0149] In this embodiment, the calculation process for obtaining the voltage difference by comparing the voltage values ​​at both ends of the switching device 300 is simple and the obtained voltage difference result is accurate.

[0150] This disclosure also provides an energy storage coupling system 200.

[0151] As shown in Figure 6, the energy storage coupling system 200 includes a switching device 300 and a first controller 230.

[0152] One end of the switching device 300 is connected to the energy storage system 210 and the photovoltaic system 220, and the other end of the switching device 300 is connected to the power grid 400 and the electrical load 500.

[0153] In this embodiment, as shown in FIG4, the switching device 300 includes at least a first branch 310 and a second branch 320 connected in parallel. The first branch 310 is provided with at least one first mechanical switch 330, and the second branch 320 is provided with at least one first semiconductor switch 340.

[0154] In this embodiment, the first controller 230 is connected to the switching device 300, and the first controller 230 is configured to execute the control method of the energy storage coupling system described above.

[0155] According to the energy storage coupling system 200 provided in the embodiments of this disclosure, the first mechanical switch 330 and the first semiconductor switch 340 in the switching device 300 are connected in parallel. One end of the switching device 300 is connected to the energy storage system 210 and the photovoltaic system 220, and the other end is connected to the power grid 400. When the power grid 400 supplies power normally, the first semiconductor switch 340 is first controlled to be turned on. After the voltage difference across the first mechanical switch 330 is reduced to the voltage difference that the first mechanical switch 330 can withstand when it is closed, the first mechanical switch 330 is then closed. This can prevent the first mechanical switch 330 from arcing due to the excessive voltage difference it withstands, thereby causing damage and ensuring the safe operation of the switching device 300.

[0156] In some embodiments, the energy storage coupling system 200 further includes:

[0157] Multiple inverters 240 are connected in parallel at one end of the switching device 300. The inverters 240 are configured to transform the output current of the energy storage system 210 or the output current of the photovoltaic system 220.

[0158] In this embodiment, the input terminal of the inverter 240 can be connected to the output terminal of the energy storage system 210, and the output terminal of the inverter 240 is connected to the first terminal 350 of the switching device 300. The inverter 240 can convert the DC power output by the energy storage system 210 into AC power for output.

[0159] The input terminal of the inverter 240 can be connected to the output terminal of the photovoltaic system 220, and the output terminal of the inverter 240 is connected to the first terminal 350 of the switching device 300. The inverter 240 can convert the DC power output by the photovoltaic system 220 into AC power for output.

[0160] In this embodiment, as shown in FIG6, the energy storage system 210 can correspond to one inverter 240, and the photovoltaic system 220 can correspond to one inverter 240.

[0161] In this embodiment, the energy storage coupling system 200 includes multiple inverters 240, which can improve the reliability and operating efficiency of the energy storage coupling system 200.

[0162] This disclosure also provides an inverter device 240.

[0163] As shown in Figure 7, the inverter device 240 includes an inverter module 241, a switching device 300, and a second controller 242.

[0164] The input terminal of the inverter module 241 is connected to the energy storage system 210 or the photovoltaic system 220. The output terminal of the inverter module 241 is connected to the power grid 400 and the electrical load 500 through the switching device 300. The switching device 300 includes at least a first branch 310 and a second branch 320 connected in parallel. The first branch 310 is provided with at least one first mechanical switch 330, and the second branch 320 is provided with at least one first semiconductor switch 340.

[0165] The second controller 242 is connected to the switching device 300 and is configured to execute the control method of the energy storage coupling system 200 described above.

[0166] The inverter module 241 is configured to transform the output current of the energy storage system 210 or the output current of the photovoltaic system 220.

[0167] In this embodiment, the input terminal of the inverter module 241 can be connected to the output terminal of the energy storage system 210, and the output terminal of the inverter module 241 is connected to the first terminal 350 of the switching device 300. The inverter module 241 can convert the DC power output by the energy storage system 210 into AC power for output.

[0168] The input terminal of the inverter module 241 can be connected to the output terminal of the photovoltaic system 220, and the output terminal of the inverter module 241 is connected to the first terminal 350 of the switching device 300. The inverter module 241 can convert the DC power output by the photovoltaic system 220 into AC power for output.

[0169] According to the inverter device 240 provided in the embodiments of this disclosure, the first mechanical switch 330 and the first semiconductor switch 340 in the switching device 300 are connected in parallel. One end of the switching device 300 is connected to the energy storage system 210 and the photovoltaic system 220, and the other end is connected to the power grid 400. When the power grid 400 supplies power normally, the first semiconductor switch 340 is first controlled to be turned on. After the voltage difference across the first mechanical switch 330 is reduced to the voltage difference that the first mechanical switch 330 can withstand when it is closed, the first mechanical switch 330 is then closed. This can prevent the first mechanical switch 330 from arcing due to the excessive voltage difference it withstands, thereby preventing damage and ensuring the safe operation of the switching device 300.

[0170] In some embodiments, as shown in FIG8, this disclosure also provides an electronic device 800, including a processor 801, a memory 802, and a computer program stored in the memory 802 and executable on the processor 801. When the program is executed by the processor 801, it implements the various processes of the control method embodiment of the energy storage coupling system 200 described above and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0171] In this embodiment, the electronic device in this disclosure includes the mobile electronic device and the non-mobile electronic device described above.

[0172] This disclosure also provides a non-transitory computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the various processes of the control method embodiment of the energy storage coupling system 200 described above and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0173] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0174] This disclosure also provides a computer program product, including a computer program that, when executed by a processor, implements the control method of the energy storage coupling system 200 described above.

[0175] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0176] This disclosure also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is configured to run programs or instructions to implement the various processes of the control method embodiment of the energy storage coupling system 200 described above, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0177] It should be understood that the chip mentioned in the embodiments of this disclosure may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0178] In this embodiment, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, the scope of the methods and apparatuses in this disclosure is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0179] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this disclosure.

[0180] The embodiments of this disclosure have been described above with reference to the accompanying drawings. However, this disclosure is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this disclosure without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this disclosure.

[0181] In the description of this disclosure, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this disclosure, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0182] Although embodiments of this disclosure have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A control method for an energy storage coupled system, wherein, The energy storage coupling system includes a switching device, one end of which is connected to the energy storage system and the photovoltaic system, and the other end of which is connected to the power grid and the electrical load. The switching device includes at least a first branch and a second branch connected in parallel. The first branch is equipped with at least one first mechanical switch, and the second branch is equipped with at least one first semiconductor switch. The method includes: When the energy storage coupling system is operating in off-grid mode, and the grid connection conditions are detected, the second branch is controlled to switch to the on state. When the voltage difference across the switching device is detected to be less than a preset voltage threshold, the first branch is controlled to switch to the conducting state.

2. The control method for the energy storage coupling system according to claim 1, wherein, The method further includes: When the energy storage coupling system is operating in grid-connected mode and both the first branch and the second branch are in the conducting state, when the off-grid conditions are detected, the first branch and the second branch are controlled to switch to the disconnected state to disconnect from the power grid.

3. The control method for the energy storage coupling system according to claim 2, wherein, The control of switching the first branch and the second branch to the disconnected state includes: First, control the first branch to switch to the disconnected state, and then control the second branch to switch to the disconnected state.

4. The control method for the energy storage coupling system according to claim 3, wherein, The second branch also includes a second mechanical switch connected in series with the first semiconductor switch. The step of first controlling the first branch to switch to the off state, and then controlling the second branch to switch to the off state, includes: First, control the first mechanical switch of the first branch to open, so that the first branch is switched to the open state; Then, control the first semiconductor switch of the second branch to turn off. If the current of the second branch is less than the branch current threshold, control the second mechanical switch of the second branch to open, so that the second branch switches to the open state.

5. The control method for the energy storage coupling system according to claim 1, wherein, The method further includes: When the energy storage coupling system is operating in grid-connected mode, with the first branch in the on state and the second branch in the off state, when the off-grid conditions are detected, the system first controls the second branch to switch to the on state, then controls the first branch to switch to the off state, and then controls the second branch to switch to the off state again, so as to disconnect the connection with the power grid.

6. The control method for the energy storage coupling system according to any one of claims 1-5, wherein, The second branch also includes a second mechanical switch connected in series with the first semiconductor switch. When the energy storage coupling system is operating in off-grid mode, and grid connection conditions are detected, the second branch is controlled to switch to the on state, including: First, control the second mechanical switch of the second branch to close, and then control the first semiconductor switch of the second branch to turn on, so that the second branch switches to the on state.

7. The control method for the energy storage coupling system according to any one of claims 1-6, wherein, After controlling the first branch to switch to the on state, the method further includes: Control the second branch to switch to the disconnected state.

8. The control method for the energy storage coupling system according to any one of claims 1-7, wherein, The detection of the voltage difference across the switching device includes: Collect the first voltage value at one end of the switching device and the second voltage value at the other end of the switching device; The first voltage value and the second voltage value are compared to determine the voltage difference.

9. An energy storage coupling system, wherein, include: A switching device, one end of which is connected to an energy storage system and a photovoltaic system, and the other end of which is connected to a power grid and an electrical load. The switching device includes at least a first branch and a second branch connected in parallel. The first branch is provided with at least one first mechanical switch, and the second branch is provided with at least one first semiconductor switch. A first controller is connected to the switching device and is configured to execute the control method of the energy storage coupling system according to any one of claims 1-8.

10. The energy storage coupling system according to claim 9, wherein, The energy storage coupling system also includes: Multiple inverters are connected in parallel to one end of the switching device. The inverters are configured to transform the output current of the energy storage system or the output current of the photovoltaic system.

11. An inverter device, wherein, include: Inverter module; The switching device is provided, wherein the input terminal of the inverter module is connected to an energy storage system or a photovoltaic system, and the output terminal of the inverter module is connected to the power grid and the electrical load through the switching device. The switching device includes at least a first branch and a second branch connected in parallel. The first branch is provided with at least one first mechanical switch, and the second branch is provided with at least one first semiconductor switch. A second controller is connected to the switching device and is configured to perform the control method of the energy storage coupling system according to any one of claims 1-8.

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