A shutdown device and a shutdown method thereof, and a photovoltaic system

Abstract

The present invention provides a circuit breaker and a shutdown method thereof, and a photovoltaic system. An inverter continuously and intermittently disturbs the output electrical parameters of the circuit breaker. The shutdown method comprises: the circuit breaker detects whether the output electrical parameters of the circuit breaker remain unchanged within a preset time; if so, the circuit breaker controls itself to shut down; if not, the circuit breaker maintains normal operation; that is, the shutdown condition of the circuit breaker is set to shut down if the output electrical parameters remain stable for a period of time; this solves the problem in the prior art that in a photovoltaic string with a circuit breaker, a high-voltage string feeds back to a low-voltage string, and the output current of the circuit breaker is normal, which will cause the circuit breaker of the high-voltage string to be unable to shut down, and does not meet the shutdown requirement of the circuit breaker in this scenario; and it is simple and easy to achieve the shutdown requirement of the system where the circuit breaker is located, without the need for additional modification of the hardware circuit.

Description

Technical Field

[0001] The present invention belongs to the technical field of shutdown, and more specifically, relates to a shutdown device and a shutdown method thereof, and a photovoltaic system. Background Art

[0002] like Figure 1 As shown in the figure, since each boost channel of the inverter connects to two PV strings, in actual PV grid-connected systems, the voltages of the two strings connected to the same boost channel may be inconsistent due to factors such as light obstruction, component aging, or different component quantities. When the inverter is shut down, the string with the higher voltage will reversely feed current to the string with the lower voltage.

[0003] In PV strings with circuit breakers, due to string voltage differences, reverse current will also be generated after the inverter is shut down. The high-voltage string will reverse current to the low-voltage string. In this case, because the circuit breaker output electrical parameters are stable and the circuit breaker output current is normal, the reverse current will cause the circuit breaker of the high-voltage string to fail to shut down, which does not meet the circuit breaker shutdown requirements in this scenario. Summary of the Invention

[0004] In view of this, an object of the present invention is to provide a circuit breaker and a shutdown method thereof, and a photovoltaic system, which are used to achieve the shutdown requirement of the system where the circuit breaker is located, and are simple and easy to implement without requiring additional modification to the hardware circuit.

[0005] In a first aspect, the present application discloses a method for shutting down a circuit breaker, wherein an inverter continuously and periodically disturbs an output electrical parameter of the circuit breaker. The method comprises:

[0006] The circuit breaker detects whether the output electrical parameter of the circuit breaker remains unchanged within a preset time;

[0007] If so, the circuit breaker controls itself to shut down;

[0008] If not, the circuit breaker maintains normal operation.

[0009] Optionally, in the above-mentioned method for shutting down a circuit breaker, before the circuit breaker maintains normal operation, the method further includes:

[0010] The circuit breaker detects whether the output electrical parameter of the circuit breaker fluctuates a preset number of times within a preset time;

[0011] If yes, executing the step of maintaining normal operation of the circuit breaker;

[0012] If not, the step of controlling the circuit breaker to shut itself down is executed.

[0013] Optionally, in the above-mentioned method for shutting down a circuit breaker, the circuit breaker detecting whether an output electrical parameter of the circuit breaker fluctuates a preset number of times within a preset time includes:

[0014] The circuit breaker detects whether an output electrical parameter of the circuit breaker fluctuates at least twice within a preset time.

[0015] Optionally, in the above-mentioned shutdown method of the circuit breaker, the fluctuation is at least one of a decrease, an increase, an increase first and then a decrease, and a decrease first and then an increase of the output electrical parameter of the circuit breaker.

[0016] Optionally, in the above-mentioned shutdown method of the circuit breaker, the output electrical parameter is the output voltage and / or the output current.

[0017] Optionally, in the above-mentioned method for shutting down the circuit breaker, the method further includes:

[0018] The inverter detects whether it needs to continue operating;

[0019] If so, the controller controls its own operation and disturbs the output electrical parameters of the circuit breaker to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

[0020] Optionally, in the above-mentioned method for shutting down a circuit breaker, disturbing the output electrical parameter of the circuit breaker to cause the corresponding output electrical parameter of the circuit breaker to fluctuate includes:

[0021] When the Boost circuit of the inverter is not working, the DC bus electrical parameters of the inverter are disturbed to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

[0022] Optionally, in the above-mentioned method for shutting down a circuit breaker, disturbing the output electrical parameter of the circuit breaker to cause the corresponding output electrical parameter of the circuit breaker to fluctuate includes:

[0023] Under the working condition of the Boost circuit of the inverter, the input electrical parameters of the Boost circuit are disturbed to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

[0024] Optionally, in the above-mentioned method for shutting down the switch, the time during which the inverter disturbs the output electrical parameter of the switch is greater than or equal to a sampling interval of the output electrical parameter of the switch.

[0025] A second aspect of the present application discloses a circuit breaker, comprising: a controller, a detection unit, a controllable switch, and a diode;

[0026] The first end of the controllable switch serves as the positive input terminal of the circuit breaker;

[0027] The second end of the controllable switch is connected to the cathode of the diode, and the connection point serves as the positive output terminal of the circuit breaker;

[0028] The anode of the diode serves as the negative electrode of the input terminal and the negative electrode of the output terminal of the circuit breaker respectively;

[0029] The detection unit is used to detect the output electrical parameters of the circuit breaker and transmit them to the controller;

[0030] The control end of the controllable switch is connected to the control end of the controller;

[0031] The controller is used to execute the control method of the circuit breaker described in the corresponding item of the first aspect of this application.

[0032] A third aspect of the present application discloses a photovoltaic system comprising: at least one photovoltaic string and at least one inverter;

[0033] The DC side of the corresponding inverter is connected to the output end of the corresponding photovoltaic string;

[0034] The photovoltaic string comprises: a plurality of photovoltaic modules and a plurality of circuit breakers disclosed in the second aspect of the present application;

[0035] The output end of the photovoltaic module is connected to the input end of the corresponding circuit breaker;

[0036] The output ends of the circuit breakers of the same photovoltaic string are cascaded, and the two ends of the cascaded connection serve as the output ends of the corresponding photovoltaic string.

[0037] Optionally, in the above photovoltaic system, the inverter includes: a boost circuit and an inverter circuit;

[0038] One side of the boost circuit serves as the DC side of the inverter;

[0039] The other side of the boost circuit is connected to the DC side of the inverter circuit via a DC bus;

[0040] The AC side of the inverter circuit serves as the AC side of the inverter.

[0041] Optionally, in the above photovoltaic system, the inverter is used to detect whether it needs to continue operating; if so, it controls its own operation and disturbs the output electrical parameters of the photovoltaic string to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

[0042] Optionally, in the above photovoltaic system, further comprising: at least one energy storage unit;

[0043] Each of the energy storage units is connected to the DC bus of the corresponding inverter.

[0044] As can be seen from the above technical solution, the present invention provides a shutdown method for a circuit breaker, in which the inverter continuously and intermittently disturbs the output electrical parameters of the circuit breaker. The shutdown method includes: the circuit breaker detects whether the output electrical parameters of the circuit breaker remain unchanged within a preset time; if so, the circuit breaker controls itself to shut down; if not, the circuit breaker maintains normal operation; that is, the shutdown condition of the circuit breaker is set to shut down if the output electrical parameters remain stable for a period of time; this solves the problem in the prior art that in photovoltaic strings with circuit breakers, due to the difference in string voltages, a backflow current will also be generated after the inverter is shut down, and the high-voltage string will backflow to the low-voltage string. At this time, since the output electrical parameters of the circuit breaker are stable and the output current of the circuit breaker is normal, that is, the backflow current will cause the circuit breaker of the high-voltage string to fail to shut down, which does not meet the shutdown requirements of the circuit breaker in this scenario; it is simple and easy to achieve the shutdown requirements of the system where the circuit breaker is located, and no additional modification of the hardware circuit is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 It is a schematic diagram of a photovoltaic system provided by the prior art;

[0047] Figure 2 This is a flow chart of a method for shutting down a circuit breaker provided by an embodiment of the present invention;

[0048] Figure 3 is a flow chart of another method for shutting down a circuit breaker provided by an embodiment of the present invention;

[0049] Figure 4 is a flow chart of another method for shutting down a circuit breaker provided by an embodiment of the present invention;

[0050] Figure 5 is a flow chart of another method for shutting down a circuit breaker provided by an embodiment of the present invention;

[0051] Figure 6 This is a disturbance timing diagram in a shutdown method of a shutdown device provided by an embodiment of the present invention;

[0052] Figure 7 is a schematic diagram of a circuit breaker provided by an embodiment of the present invention;

[0053] Figure 8 is a schematic diagram of a photovoltaic system provided by an embodiment of the present invention;

[0054] Figure 9 Schematic diagram of a photovoltaic system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0056] In this application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0057] In a first aspect, the present application discloses a method for shutting down a circuit breaker, which is used to solve the problem in the prior art that in photovoltaic strings with circuit breakers, due to the voltage difference between the strings, a backflow current will also be generated after the inverter is shut down, and the high-voltage string will backflow to the low-voltage string. At this time, since the output electrical parameters of the circuit breaker are stable and the output current of the circuit breaker is normal, that is, the backflow current will cause the circuit breaker of the high-voltage string to be unable to shut down, which does not meet the shutdown requirements of the circuit breaker in this scenario.

[0058] It should be noted that the input end of the circuit breaker is connected to the photovoltaic module; the output end of the circuit breaker is connected to the inverter through the DC bus.

[0059] See also Figure 2 , the control method of the circuit breaker includes:

[0060] S101: The circuit breaker detects whether the output electrical parameters of the circuit breaker remain unchanged within a preset time.

[0061] Among them, the fluctuation of the output electrical parameters of the circuit breaker can be controlled by the inverter disturbance; that is, when the inverter is working, it continuously and intermittently disturbs the output electrical parameters of the circuit breaker to cause the output electrical parameters of the circuit breaker to fluctuate. When the inverter is not working and shuts down, the inverter cannot continue to disturb the output electrical parameters of the circuit breaker. In this case, the output electrical parameters of the circuit breaker will remain unchanged.

[0062] During normal operation, the DC bus voltage will fluctuate to a certain extent, that is, it will not remain unchanged within a preset time; in a fault or shutdown state, the DC bus voltage will remain unchanged.

[0063] If the output electrical parameter of the circuit breaker detected by the circuit breaker remains unchanged within the preset time, step S102 is executed.

[0064] S102: The circuit breaker controls itself to shut down.

[0065] If the output electrical parameter of the circuit breaker detected by the circuit breaker does not remain unchanged within the preset time, step S103 is executed.

[0066] S103. The circuit breaker maintains normal operation.

[0067] It should be noted that when the circuit breaker is turned off, the connection between the corresponding device connected to the input of the circuit breaker and the inverter is disconnected; when the circuit breaker maintains normal operation, the connection between the corresponding device connected to the input of the circuit breaker and the inverter is maintained. In other words, the corresponding device at the input of the circuit breaker can output energy to the inverter through the circuit breaker.

[0068] In this embodiment, the circuit breaker detects whether the output electrical parameters of the circuit breaker remain unchanged within a preset time; if so, the circuit breaker controls itself to shut down; if not, the circuit breaker maintains normal operation; that is, the shutdown condition of the circuit breaker is set to shut down when the output electrical parameters remain stable for a period of time; this solves the problem in the prior art that in photovoltaic strings with circuit breakers, due to the difference in string voltages, a backflow current will also be generated after the inverter is shut down, and the high-voltage string will backflow to the low-voltage string. At this time, since the output electrical parameters of the circuit breaker are stable and the output current of the circuit breaker is normal, that is, the backflow current will cause the circuit breaker of the high-voltage string to fail to shut down, which does not meet the shutdown requirements of the circuit breaker in this scenario; it is simple and easy to implement the shutdown requirements of the system where the circuit breaker is located, and no additional modification of the hardware circuit is required.

[0069] In practical applications, see Figure 3 , before step S103, the circuit breaker maintains normal operation, the process further includes:

[0070] S201: The circuit breaker detects whether an output electrical parameter of the circuit breaker fluctuates a preset number of times within a preset time.

[0071] It should be noted that as long as the output electrical parameters of the circuit breaker fluctuate within the preset time, it means that the output electrical parameters of the circuit breaker have not remained unchanged within the preset time; as long as the output electrical parameters of the circuit breaker do not fluctuate within the preset time, it means that the output electrical parameters of the circuit breaker have remained unchanged within the preset time.

[0072] Specifically, the preset number of times may be 1 or at least 2 times.

[0073] The specific values ​​of the preset number of times will not be described here in detail. They will be determined according to the actual situation and are all within the scope of protection of this application.

[0074] If the circuit breaker detects that the output electrical parameter of the circuit breaker fluctuates a preset number of times within a preset time, step S103 is executed and the circuit breaker maintains normal operation.

[0075] If the circuit breaker detects that the output electrical parameter of the circuit breaker does not fluctuate for a preset number of times within a preset time, step S102 is executed, and the circuit breaker controls itself to shut down.

[0076] In practical applications, the preset time is 10 seconds; alternatively, the preset time is 15 seconds. The specific value of the preset time is not described here in detail, and can be determined according to the actual situation, all of which are within the scope of protection of this application.

[0077] In practical applications, see Figure 4 Step S201: The circuit breaker detects whether the output electrical parameter of the circuit breaker fluctuates a preset number of times within a preset time, including:

[0078] S301: The circuit breaker detects whether an output electrical parameter of the circuit breaker fluctuates at least twice within a preset time.

[0079] If the circuit breaker detects that the output electrical parameter of the circuit breaker fluctuates at least twice within the preset time, step S103 is executed.

[0080] If the circuit breaker detects that the output electrical parameter of the circuit breaker does not fluctuate at least twice within the preset time, step S102 is executed.

[0081] The output electrical parameter may be at least one of an output voltage and an output current; of course, other forms are not excluded, which will not be detailed here one by one. It depends on the actual situation and is within the scope of protection of this application.

[0082] In practical applications, the fluctuation is at least one of a decrease, an increase, an increase first and then a decrease, and a decrease first and then an increase in the output electrical parameter of the circuit breaker.

[0083] That is to say, the fluctuation is one of the following: the output electrical parameter of the circuit breaker decreases, increases, increases first and then decreases, or decreases first and then increases; or, the fluctuation is a combination of at least two of the output electrical parameter of the circuit breaker decreases, increases, increases first and then decreases, or decreases first and then increases.

[0084] Of course, it is not ruled out that the fluctuation may be due to other situations, which will not be described here one by one. It depends on the actual situation and is within the scope of protection of this application.

[0085] In practical applications, see Figure 5 , also includes:

[0086] S401: The inverter detects whether it needs to continue operating.

[0087] If so, execute step S402.

[0088] S402: Control its own operation and disturb the output electrical parameters of the circuit breaker to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

[0089] In practical applications, the specific process of disturbing the output electrical parameters of the circuit breaker to cause the output electrical parameters of the corresponding circuit breaker to fluctuate may be: when the Boost circuit of the inverter is not working, disturbing the DC bus electrical parameters of the inverter to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

[0090] The specific process of disturbing the output electrical parameters of the switch to cause the corresponding output electrical parameters of the switch to fluctuate may also be: under the working condition of the Boost circuit of the inverter, disturbing the input electrical parameters of the Boost circuit to cause the corresponding output electrical parameters of the switch to fluctuate.

[0091] The specific disturbance control is to perform disturbance on the corresponding devices in the working state in the inverter, so as to directly or indirectly disturb the output electrical parameters of the circuit breaker. It will not be described in detail here, and all are within the protection scope of this application.

[0092] If not, the inverter is shut down, and the output electrical parameters of the circuit breaker tend to be stable.

[0093] In practical applications, the time during which the inverter disturbs the output electrical parameters of the circuit breaker is greater than or equal to the sampling interval of the output electrical parameters of the circuit breaker, so as to ensure that the disturbance of the output electrical parameters of the circuit breaker by the inverter is detected by the circuit breaker.

[0094] like Figure 6 As shown, the shutdown condition of the circuit breaker is set to be that the output electrical parameters of the circuit breaker remain unchanged for a preset time t2 and then the circuit breaker is shut down; during normal operation, the inverter periodically disturbs the inverter input voltage to continuously notify the circuit breaker to maintain the on state. Figure 6 In FIG, Boost1, Boost2, and Boost3 are all change curves of the input voltage Vpv of the corresponding boost circuits.

[0095] The following describes the specific process of combining the circuit breaker and inverter:

[0096] During normal operation of the inverter, the output electrical parameters of the circuit breaker are periodically controlled to fluctuate. When the inverter no longer disturbs the output electrical parameters of the circuit breaker or the inverter is shut down, it indicates that the circuit breaker needs to be shut down.

[0097] The circuit breaker monitors its own output electrical parameters in real time. If periodic fluctuations are detected in the output electrical parameters, the circuit breaker remains on. If no fluctuations are detected for a preset time, the circuit breaker shuts down. The preset time here refers to the circuit breaker's shutdown time, which can be 10s or 15s, depending on the actual system specifications.

[0098] It should be noted that, since the inverter will periodically disturb its own input voltage during normal operation, in order to reduce the impact on the output power, when multiple boost circuits are working, the disturbances of each boost circuit are staggered, such as Figure 8 As shown in the figure, if the boost circuit is not working during operation, that is, the input voltage of the inverter is relatively high and does not need to be increased by the boost circuit, the input voltages of each line will be disturbed synchronously. In this case, one side of the inverter is connected to the circuit breaker, and the output electrical parameters of the circuit breaker can be regarded as equivalent to the input voltage of the inverter.

[0099] The selection of the voltage disturbance period at the input end of the inverter needs to satisfy the requirement of at least 2 disturbances within the shutdown time of the circuit breaker. Here, 4s or 5s are selected. The disturbance can be in the form of a decrease, increase, increase first and then decrease, or decrease first and then increase of the input voltage of the inverter. The selection of the range V1 of the input voltage disturbance of the inverter needs to consider the length of the circuit breaker string and the voltage recognition accuracy. 100V, 150V, etc. can be selected.

[0100] The input voltage disturbance time t1 of the inverter needs to take into account the sampling time of the output electrical parameters of the circuit breaker, and can be selected as 200ms or 500ms.

[0101] Of course, other values ​​are possible, which will not be detailed here. It depends on the actual situation and is within the scope of protection of this application.

[0102] In this embodiment, the shutdown condition of the circuit breaker is set to be that the circuit breaker is shut down when the output electrical parameters remain stable within a preset time; when the system is operating normally, the inverter is required to perturb the input voltage, that is, the output electrical parameters of the circuit breaker, according to a specific period to create fluctuations in the output electrical parameters of the circuit breaker; when the system includes multiple boost circuits, in order to reduce the impact on the output power, when the multiple boost circuits are working, each boost circuit is perturbed at intervals, and when the boost circuits are not working, the boost circuits are perturbed synchronously.

[0103] Another embodiment of the present application provides a circuit breaker.

[0104] See also Figure 7 The circuit breaker includes: a controller (not shown in the figure), a detection unit (not shown in the figure), a controllable switch T and a diode D.

[0105] The first end of the controllable switch T serves as the positive input terminal of the circuit breaker and is connected to the positive electrode of the solar panel.

[0106] The second end of the controllable switch T is connected to the cathode of the diode D, and the connection point serves as the positive output terminal of the circuit breaker and is connected to the positive electrode of the DC bus.

[0107] The anode of the diode D serves as the negative electrode of the input end and the negative electrode of the output end of the circuit breaker, and is connected to the negative electrode of the DC bus and the negative electrode of the battery panel respectively.

[0108] The detection unit is used to detect the output electrical parameters of the circuit breaker and transmit them to the controller. Specifically, the input of the detection unit is connected to the output of the circuit breaker to detect the output electrical parameters, while the output of the detection unit is connected to the input of the controller to transmit the output electrical parameters to the controller. The output electrical parameters include the output current Iout and / or the output voltage Uout.

[0109] The control end of the controllable switch T is connected to the control end of the controller, so that the controller controls the on and off of the controllable switch to realize the off and operation control of the circuit breaker.

[0110] The controller is used to execute a control method for the circuit breaker.

[0111] The specific process and principle of the controller are detailed in the control method of the circuit breaker provided in the above embodiment, which will not be described here one by one, and are all within the scope of protection of this application.

[0112] It should be noted that the controller is the controller of the circuit breaker. In the above-mentioned control method of the circuit breaker, the part requiring the cooperation of the inverter is not an execution step of the controller.

[0113] like Figure 7 As shown, Uin is the input voltage of the circuit breaker, that is, the output voltage of the solar panel; Uout is the output voltage of the circuit breaker; Iout is the output current of the circuit breaker.

[0114] Another embodiment of the present application provides a photovoltaic system.

[0115] See also Figure 8 The photovoltaic system includes: at least one photovoltaic string and at least one inverter 204.

[0116] The DC side of the corresponding inverter 204 is connected to the output end of the corresponding photovoltaic string.

[0117] The inverter 204 can be connected to the grid or to the corresponding load. That is to say, the photovoltaic system can be off-grid or grid-connected. There is no specific limitation here. It depends on the actual situation and is within the protection scope of this application.

[0118] The photovoltaic string includes: a plurality of photovoltaic modules 201 and a plurality of circuit breakers 202 .

[0119] The output end of the photovoltaic assembly 201 is connected to the input end of the corresponding circuit breaker 202 .

[0120] It should be noted that the photovoltaic components 201 and the circuit breakers 202 may be in a one-to-one correspondence (eg Figure 8 It can be a one-to-many relationship (not shown), or a many-to-one relationship (not shown); no specific limitation is given here, and it depends on the actual situation, and all are within the scope of protection of this application.

[0121] The output ends of the various circuit breakers 202 of the same photovoltaic string are cascaded, and the two ends of the cascaded connection serve as the output ends of the corresponding photovoltaic string.

[0122] The specific structure and working process of the circuit breaker 202 are detailed in the circuit breaker provided in the above embodiment, which will not be described here in detail, and are all within the protection scope of this application.

[0123] In practical applications, such as Figure 9 As shown, the inverter 204 includes a boost circuit 302 and an inverter circuit 301 .

[0124] One side of the boost circuit 302 serves as the DC side of the inverter 204 .

[0125] The other side of the boost circuit 302 is connected to the DC side of the inverter circuit 301 via a DC bus.

[0126] The AC side of the inverter circuit 301 serves as the AC side of the inverter 204 .

[0127] It should be noted that the output electrical parameter of the circuit breaker 202 is the input voltage of the inverter 204. When the boost circuit 302 of the inverter 204 is working, the input voltage of the inverter 204 is boosted to obtain the DC bus voltage; when the boost circuit 302 of the inverter 204 is not working, the DC bus voltage is the input voltage of the inverter 204.

[0128] In actual applications, when the Boost circuit 302 of the inverter 204 is not operating, the DC bus electrical parameters of the inverter 204 are disturbed to cause fluctuations in the corresponding output electrical parameters of the circuit breaker 202. When the Boost circuit 302 of the inverter 204 is operating, the input electrical parameters of the Boost circuit 302 are disturbed to cause fluctuations in the corresponding output electrical parameters of the circuit breaker 202.

[0129] It should be noted that there are multiple possible positions for the DC bus. The first one is that the DC bus can be set before the boost circuit 302, that is, the photovoltaic string and the inverter 204 are connected through the DC bus; when the boost circuit 302 is working, the DC bus electrical parameters are disturbed, and when the boost circuit 302 is not working, the input electrical parameters of the inverter circuit 301 are disturbed.

[0130] The second is: the DC bus can also be set after the boost circuit 302, that is, the other side of the boost circuit 302 is connected to the DC side of the inverter circuit 301 through the DC bus; in the second case, when the boost circuit 302 is working, the input electrical parameters of the boost circuit 302 are disturbed, and when the boost circuit 302 is not working, the electrical parameters of the DC bus between the boost circuit 302 and the inverter circuit 301 are disturbed.

[0131] The third option is to install the DC bus within inverter circuit 301. Other options are possible, and we will not elaborate on them here. These options are determined based on the actual situation and fall within the scope of this application. Specifically, the disturbance control can be performed by perturbing the corresponding operating components of inverter 204, thereby directly or indirectly perturbing the output electrical parameters of circuit breaker 202. These options are not elaborated on here and fall within the scope of this application.

[0132] The inverter 204 is used to detect whether it needs to continue to operate; if so, it controls its own operation and disturbs the output electrical parameters of the circuit breaker to cause the output electrical parameters of the corresponding circuit breaker 202 to fluctuate.

[0133] In practical applications, it also includes: at least one energy storage unit (not shown in the figure).

[0134] Each energy storage unit is connected to the DC bus of the corresponding inverter 204 .

[0135] Specifically, the positive electrode of the energy storage unit is connected to the positive electrode of the DC bus of the inverter 204 , and the negative electrode of the energy storage unit is connected to the negative electrode of the DC bus of the inverter 204 .

[0136] It should be noted that the energy storage units can be connected in series and / or in parallel, and the specific connection forms will not be described here one by one. As long as each energy storage unit is directly or indirectly connected to the corresponding inverter DC bus, it is within the scope of protection of this application.

[0137] That is to say, the circuit breaker can be applied to a single photovoltaic system or to a photovoltaic storage system that combines a photovoltaic system and an energy storage system; of course, other application scenarios are not excluded, which will not be described here one by one, and are all within the scope of protection of this application.

[0138] The features described in the various embodiments of this specification can be replaced or combined with each other. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0139] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0140] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for shutting down a circuit breaker, characterized in that: The inverter continuously and intervally disturbs the output electrical parameters of the circuit breaker, and the circuit breaker method includes: The circuit breaker detects whether the output electrical parameter of the circuit breaker remains unchanged within a preset time; If so, the circuit breaker controls itself to shut down; If not, the circuit breaker maintains normal operation; Wherein, when the boost circuit of the inverter is not working, the input voltages of each channel are disturbed synchronously; Under the working condition of the boost circuit of the inverter, the boost circuits are staggered in disturbance.

2. The method for shutting down a circuit breaker according to claim 1, wherein: Before the circuit breaker maintains normal operation, the method further comprises: The circuit breaker detects whether the output electrical parameter of the circuit breaker fluctuates a preset number of times within a preset time; If yes, executing the step of maintaining normal operation of the circuit breaker; If not, the step of controlling the circuit breaker to shut itself down is executed.

3. The method for shutting down a circuit breaker according to claim 1, wherein: The circuit breaker detects whether an output electrical parameter of the circuit breaker fluctuates a preset number of times within a preset time, including: The circuit breaker detects whether an output electrical parameter of the circuit breaker fluctuates at least twice within a preset time.

4. The method for shutting down a circuit breaker according to claim 2, wherein: The fluctuation is at least one of a decrease, an increase, an increase first and then a decrease, and a decrease first and then an increase in the output electrical parameter of the circuit breaker.

5. The method for shutting down a circuit breaker according to claim 1, wherein: The output electrical parameter is output voltage and / or output current.

6. The method for shutting down a circuit breaker according to any one of claims 1 to 5, characterized in that: Also includes: The inverter detects whether it needs to continue operating; If so, the controller controls its own operation and disturbs the output electrical parameters of the circuit breaker to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

7. The method for shutting down a circuit breaker according to claim 6, wherein: Disturbing the output electrical parameters of the circuit breaker to cause the corresponding output electrical parameters of the circuit breaker to fluctuate, comprising: Under the working condition that the boost circuit of the inverter is not working, the DC bus electrical parameters of the inverter are disturbed to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

8. The method for shutting down a circuit breaker according to claim 6, wherein: Disturbing the output electrical parameters of the circuit breaker to cause the corresponding output electrical parameters of the circuit breaker to fluctuate, comprising: Under the working condition of the boost circuit of the inverter, the input electrical parameters of the boost circuit are disturbed to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

9. The method for shutting down a circuit breaker according to claim 6, wherein: The time during which the inverter disturbs the output electrical parameter of the circuit breaker is greater than or equal to a sampling interval of the output electrical parameter of the circuit breaker.

10. A circuit breaker, characterized in that: include: Controller, detection unit, controllable switch and diode; The first end of the controllable switch serves as the positive input terminal of the circuit breaker; The second end of the controllable switch is connected to the cathode of the diode, and the connection point serves as the positive output terminal of the circuit breaker; The anode of the diode serves as the negative electrode of the input terminal and the negative electrode of the output terminal of the circuit breaker respectively; The detection unit is used to detect the output electrical parameters of the circuit breaker and transmit them to the controller; The control end of the controllable switch is connected to the control end of the controller; The controller is used to execute the method for controlling a circuit breaker according to any one of claims 1 to 5.

11. A photovoltaic system, characterized in that: include: at least one photovoltaic string and at least one inverter; The DC side of the corresponding inverter is connected to the output end of the corresponding photovoltaic string; The photovoltaic string comprises: a plurality of photovoltaic modules and a plurality of circuit breakers according to claim 10; The output end of the photovoltaic module is connected to the input end of the corresponding circuit breaker; The output ends of the circuit breakers of the same photovoltaic string are cascaded, and the two ends of the cascaded connection serve as the output ends of the corresponding photovoltaic string.

12. The photovoltaic system according to claim 11, characterized in that: The inverter includes: a boost circuit and an inverter circuit; One side of the boost circuit serves as the DC side of the inverter; The other side of the boost circuit is connected to the DC side of the inverter circuit via a DC bus; The AC side of the inverter circuit serves as the AC side of the inverter.

13. The photovoltaic system according to claim 11 or 12, characterized in that: The inverter is used to detect whether it needs to continue to operate; if so, it controls its own operation and disturbs the output electrical parameters of the photovoltaic string to cause the output electrical parameters of the corresponding circuit breaker to fluctuate.

14. The photovoltaic system according to claim 11 or 12, characterized in that: Also includes: at least one energy storage unit; Each of the energy storage units is connected to the DC bus of the corresponding inverter.

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