Photovoltaic system and turn-off control method

Abstract

The invention relates to a photovoltaic system and a turn-off control method. Each turn-off device in the photovoltaic system is used for adjusting the next preset duration according to whether turn-on signals are continuously received in the current preset duration and a preset rule. In the embodiment of the invention, the turn-off time of each photovoltaic turn-off device can be adaptively adjusted according to the condition of the received turn-on signal and the preset rule, so that dynamic adjustment can be realized no matter in a severe working condition or in an environment with good communication, the dual requirements of safe and rapid turn-off response are met, and the safety of the photovoltaic power generation system is improved. The self-adaptive adjustment of the turn-off time optimizes the turn-off speed while ensuring the safety, thereby improving the performance and reliability of the whole photovoltaic system.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaics, and in particular to a photovoltaic system and a shutdown control method. Background Art

[0002] Photovoltaic system is a power generation system that converts solar energy directly into electrical energy. In photovoltaic system, photovoltaic circuit breakers are used to quickly cut off the power supply of photovoltaic modules in emergency, failure or maintenance, thereby eliminating DC high voltage, making the system safe and ensuring the safety of personnel and equipment. The circuit breaker controls the output of photovoltaic modules through the internal main switch tube. When receiving the conduction signal, the circuit breaker remains in the open state; when the signal disappears or is interrupted, the circuit breaker cuts off or reduces the output voltage of the photovoltaic module.

[0003] In the prior art, the off time of the circuit breaker is usually a fixed value. Although the fixed off time simplifies the complexity of the control system, it also has some problems. Specifically, if the set off time is too short, then under harsh working conditions (such as communication signal attenuation or interference), the circuit breaker may not be able to successfully receive the conduction signal within the fixed off time, which will cause the circuit breaker to misjudge and cut off or reduce the output of the photovoltaic module, which will not only reduce the power generation of the photovoltaic system, but also may cause the system to misjudge as an undervoltage fault (for example, multiple circuit breakers are misjudged), causing the system to enter a safe mode and stop outputting electricity, seriously affecting the power supply stability and reliability of the photovoltaic system. If the set off time is too long, the circuit breaker cannot respond quickly. In an emergency, if the circuit breaker cannot quickly cut off the output of the photovoltaic module, it may pose a threat to personnel safety. At the same time, it may also aggravate the degree of system failure due to the inability to cut off quickly.

[0004] Therefore, how to reasonably set the shutdown time of the shutdown device is an urgent problem to be solved. Summary of the invention

[0005] In view of this, embodiments of the present application provide a photovoltaic system and a shutdown control method to solve at least one problem existing in the background technology.

[0006] In a first aspect, an embodiment of the present application provides a photovoltaic system, the photovoltaic system comprising an inverter, one or more photovoltaic strings and a transmitter, the photovoltaic strings being connected to the inverter and the transmitter respectively, the inverter being used to convert the direct current output by the photovoltaic strings into alternating current and output it, the transmitter being used to send a conduction signal to the photovoltaic strings at a fixed time period; each of the photovoltaic strings comprising a plurality of photovoltaic units connected in series, each of the photovoltaic units comprising a circuit breaker and one or more photovoltaic components connected to the circuit breaker; each of the circuit breakers being used to determine whether the main switch tube of the circuit breaker is turned off according to whether the conduction signal has not been received continuously within a current preset time length; Each of the switches is further configured to adjust a next preset time duration according to whether the conduction signal is continuously received within the current preset time duration and a preset rule.

[0007] Optionally, each of the switches is further configured to adjust the next preset time length according to whether the on signal is continuously received within the current preset time length and a preset rule, including: If the switch does not continuously receive the conduction signal within the current preset time length, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; If the switch continuously receives the conduction signal within the current preset time length, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

[0008] Optionally, the current preset duration is a duration within a preset duration range, and the duration within the preset duration range includes a preset duration lower limit value and a preset duration upper limit value; each of the switches is further configured to adjust the next preset duration according to whether the conduction signal is continuously received within the current preset duration and a preset rule, including: If the switch does not continuously receive the conduction signal within the current preset time length, and the sum of the current preset time length and the fixed preset step length is greater than the upper limit value of the preset time length range, the next preset time length is equal to the preset time length upper limit value; If the switch continuously receives the conduction signal within the current preset time length, and the difference between the current preset time length and the fixed preset step length is less than the lower limit value of the preset time length range, the next preset time length is equal to the lower limit value of the preset time length; Correspondingly, if the switch does not continuously receive the conduction signal within the current preset time length, and the sum of the current preset time length and the fixed preset step length is less than or equal to the upper limit value of the preset time length range, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; If the switch continuously receives the conduction signal within the current preset time length, and the difference between the current preset time length and the fixed preset step length is greater than or equal to the lower limit value of the preset time length range, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

[0009] Optionally, the fixed preset step size is smaller than the current preset duration, and the fixed preset step size is larger than the fixed time period.

[0010] Optionally, each of the circuit breakers is used to determine whether the main switch tube of the circuit breaker is turned off according to whether the conduction signal is not received continuously within the current preset time length, including: If the circuit breaker fails to receive the conduction signal continuously within the current preset time period, the main switch tube of the circuit breaker is turned off.

[0011] Optionally, if the circuit breaker fails to receive the conduction signal continuously within the current preset time length, after the main switch tube of the circuit breaker is turned off, the method further includes: If the circuit breaker receives the conduction signal within the next preset time period, the main switch tube of the circuit breaker is turned on.

[0012] In a second aspect, an embodiment of the present application provides a shutdown control method, which is applied to a photovoltaic system, wherein the photovoltaic system includes an inverter, one or more photovoltaic strings and a transmitter, wherein the photovoltaic strings are connected to the inverter and the transmitter respectively, wherein the inverter is used to convert the direct current output by the photovoltaic strings into alternating current and output it, and the transmitter is used to send a conduction signal to the photovoltaic strings at a fixed time period; each of the photovoltaic strings includes one or more photovoltaic units connected in series, and each of the photovoltaic units includes a circuit breaker and one or more photovoltaic components connected to the circuit breaker; the method includes: receiving the conduction signal; Determining whether the main switch is turned off according to whether the conduction signal is not received continuously within the current preset time length; The next preset time length is adjusted according to whether the conduction signal is continuously received within the current preset time length and a preset rule.

[0013] Optionally, adjusting the next preset time length according to whether the conduction signal is continuously received within the current preset time length and a preset rule includes: If the switch does not continuously receive the conduction signal within the current preset time length, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; If the switch continuously receives the conduction signal within the current preset time length, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

[0014] Optionally, the current preset duration is a duration within a preset duration range, and the duration within the preset duration range includes a preset duration lower limit value and a preset duration upper limit value; and adjusting the next preset duration according to whether the conduction signal is continuously received within the current preset duration and a preset rule includes: If the conduction signal is not received continuously within the current preset time length, and the sum of the current preset time length and the fixed preset step length is greater than the upper limit of the preset time length range, the next preset time length is equal to the preset time length upper limit; If the conduction signal is continuously received within the current preset time length, and the difference between the current preset time length and the fixed preset step length is less than the lower limit value of the preset time length range, the next preset time length is equal to the lower limit value of the preset time length; Correspondingly, if the conduction signal is not continuously received within the current preset time length, and the sum of the current preset time length and the fixed preset step length is less than or equal to the upper limit value of the preset time length range, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; If the conduction signal is continuously received within the current preset time length, and the difference between the current preset time length and the fixed preset step length is greater than or equal to the lower limit value of the preset time length range, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

[0015] Optionally, the fixed preset step size is smaller than the current preset duration, and the fixed preset step size is larger than the fixed time period.

[0016] In the embodiment of the present application, the shutdown time of each photovoltaic switch can be adaptively adjusted according to the situation of receiving the conduction signal and the preset rules, so that dynamic adjustment can be achieved regardless of whether it is under harsh working conditions or in an environment with good communication, thereby meeting the dual needs of safe and fast shutdown response. The adaptive adjustment of the shutdown time optimizes the shutdown speed while ensuring safety, thereby improving the performance and reliability of the entire photovoltaic system.

[0017] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 A schematic diagram of a photovoltaic system provided in one embodiment of the present application; Figure 2 A schematic diagram of a photovoltaic shut-off device provided in an embodiment of the present application; Figure 3The present invention is a flowchart of a shutdown control method provided in one embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the technical solutions and beneficial effects of the present invention more clearly understood, the following is a detailed description by listing specific embodiments. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.

[0020] Figure 1 This is a schematic diagram of a photovoltaic system provided by an embodiment of the present application. As shown in the figure, the photovoltaic system includes an inverter, a photovoltaic string and a transmitter. Among them, the photovoltaic string includes n photovoltaic units, each photovoltaic unit includes a circuit breaker and a photovoltaic component connected to the circuit breaker, that is, photovoltaic unit 1 photovoltaic unit 1, photovoltaic unit 2, photovoltaic unit 3...Photovoltaic unit n are respectively connected to photovoltaic component PV1, photovoltaic component PV2, photovoltaic component PV3...Photovoltaic component PVn; each photovoltaic circuit breaker includes a controller and a shutdown circuit, and the controller is connected to the shutdown circuit, that is, photovoltaic circuit breaker 1, photovoltaic circuit breaker 2, photovoltaic circuit breaker 3...Photovoltaic circuit breaker n respectively include shutdown circuit 1, shutdown circuit 2, shutdown circuit 3...Shutdown circuit n and controller 1, controller 2, controller 3...Controller n. Figure 1 In the photovoltaic system shown, each controller is used to control the on and off of a main switch in a shutdown circuit so as to enable the photovoltaic assembly connected thereto to output voltage or stop outputting voltage.

[0021] The inverter is used to convert the direct current output of the photovoltaic string into alternating current and output it. The transmitter is used to send a conduction signal to the photovoltaic string at a fixed time period. The circuit breaker is used to determine whether the main switch tube of the circuit breaker is turned off based on whether the conduction signal is not received continuously within the current preset time length. Figure 2 A schematic diagram of a photovoltaic circuit breaker provided in an embodiment of the present application. Figure 2As shown, the shutdown circuit includes a main switch tube Q1 and a bypass switch tube Q2. If the controller in the photovoltaic shut-off device does not receive a conduction signal continuously within the current preset time length, the controller in the photovoltaic shut-off device controls the main switch tube Q1 in the shutdown circuit to shut down. It should be noted that the transmitter and the photovoltaic shut-off device communicate through the power line. The transmitter will continuously send a conduction signal at a fixed time period. After each photovoltaic shut-off device in the photovoltaic string connected to the transmitter receives the conduction signal, the main switch tube Q1 is kept turned on, so that the corresponding photovoltaic component outputs voltage to the inverter; when the photovoltaic system needs to be maintained or an emergency occurs, the transmitter can be controlled to stop sending the conduction signal. At this time, when each photovoltaic shut-off device does not receive a conduction signal continuously within the preset shutdown time, the controller will control the corresponding main switch tube Q1 to shut down, so that the photovoltaic system can be quickly reduced to a safe voltage. The time it takes for the photovoltaic system to quickly drop to a safe voltage depends on the preset shutdown time of each photovoltaic circuit breaker. In the prior art, the preset shutdown time of each photovoltaic circuit breaker is fixed. However, due to the harsh and changeable power line communication environment, communication signals are easily interfered with. If the preset shutdown time is set too low, it is easy to cause false shutdowns and affect the normal operation of the photovoltaic system. If the preset shutdown time is set too long, the shutdown response time is long, and it cannot respond quickly in an emergency, which is more likely to cause safety accidents (compared with the case where the preset shutdown time is short). For example, a turn-on signal is about 1s; if the turn-off time is 13s, when the photovoltaic switch does not receive a turn-on signal within 13s (indicates that 13 turn-on signals have not been received in succession), the main switch corresponding to the photovoltaic switch will be turned off; if the turn-off time is 1s, when the photovoltaic switch does not receive a signal within 1s (indicates that only 1 turn-on signal has not been received in succession), the main switch corresponding to the photovoltaic switch will be turned off; Obviously, the turn-off time of 13s and 1s will bring different effects. When the turn-off time is 1s, it is easy to be affected by noise or environment, resulting in false shutdown, thereby affecting the stable operation of the system; and when the turn-off time is 13s, the turn-off time is too long, and it is easy to shut down in time in an emergency, causing safety hazards. It should be noted that the communication between the transmitter and the switch is carried out through the power line. Power line communication has the advantages of not requiring additional wiring, low cost, and wide communication range, but power line communication is easily interfered and the communication environment is relatively poor.

[0022] As an optional specific implementation, after the main switch tube of the photovoltaic shutdown device is turned off, it also includes: if the photovoltaic shutdown device receives a turn-on signal within the next preset time period, the controller of the photovoltaic shutdown device controls the main switch tube Q1 in the shutdown current to turn on.

[0023] As an optional specific implementation, each photovoltaic fast shut-off device in the embodiment of the present application is also used to adjust the next preset time length according to whether the conduction signal is continuously received within the current preset time length and the preset rules. Specifically, if the shut-off device does not continuously receive the conduction signal within the current preset time length, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; if the shut-off device continuously receives the conduction signal within the current preset time length, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

[0024] In the embodiment of the present application, the off time (i.e., the current preset duration) of each photovoltaic switch is not fixed, but is adaptively adjusted according to the situation of receiving the conduction signal. Specifically, if the conduction signal is not received continuously within the current preset duration, it indicates that the current preset duration may be affected by environmental noise or signal attenuation. At this time, the off time can be increased to avoid the false shutdown caused by other influences such as environmental noise in the next preset duration. For example, the fixed time period of the conduction signal is 1s, the current preset duration is 4s, and the fixed preset step size is 1s. If the conduction signal is not received continuously within 4s (for example, the interval between two adjacent conduction signals is greater than 1s), the next preset duration is 5s. If the conduction signal is still not received continuously within the next preset duration, the off time will continue to be extended. In the embodiment of the present application, when the conduction signal is continuously received within the current preset duration, the probability of not receiving the conduction signal continuously within the next preset duration can be reduced by extending the off time, thereby avoiding false shutdown. For example, if the current preset duration (shutdown time) is 4s, 4 turn-on signals can be received normally within 4s. Due to interference and attenuation, only 2 turn-on signals can be received within the current 4s. If the shut-off time remains unchanged, no turn-on signal will be received within the next 4s due to increased interference, and an error shutdown will occur at this time; if the shut-off time is adjusted to 5s, although the interference is increased, a turn-on signal can still be received (that is, received in the 5th second), which will not cause an error shutdown. If the circuit breaker receives the turn-on signal continuously within the current preset duration, it indicates that the communication is good within the current preset duration and the interference is small. At this time, by reducing the shut-off time, a faster shut-off response can be achieved, improving the safety of the photovoltaic system.

[0025] In the embodiment of the present application, the off time of each photovoltaic switch is adaptively adjusted by receiving the on signal, so that dynamic adjustment can be achieved regardless of whether it is under harsh working conditions or in a good communication environment, thereby meeting the dual requirements of safe and fast shutdown response. It should be noted that in the embodiment of the present application, the interference or attenuation of the on signal received by each photovoltaic switch is not the same. Therefore, the current preset durations between the photovoltaic switches in the entire photovoltaic system may be the same or different, depending on the signal interference or attenuation; at the same time, the current preset duration of each photovoltaic switch is not a random value or randomly assigned, but is determined according to the on signal received in the previous preset duration.

[0026] It should be noted that the switch does not continuously receive the conduction signal within the current preset time length, which means that at least one conduction signal is not received within the current preset time length. Further, if the switch does not receive at least two conduction signals within the current preset time length, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length, thereby reducing the number of adjustments, saving computing resources, and improving the overall stability of the system.

[0027] As an optional specific implementation, the off time (i.e., preset duration) of the photovoltaic switch has upper and lower limits, that is, the preset duration is a duration within the preset duration range, thereby preventing potential problems caused by frequent adjustments and ensuring safe, stable, and efficient operation of the photovoltaic system. Specifically, the upper and lower limits can be set according to actual system requirements. In the embodiment of the present application, the current preset duration is a duration within the preset duration range, and the duration within the preset duration range includes a preset duration lower limit value and a preset duration upper limit value; correspondingly, each switch is also used to adjust the next preset duration according to whether the conduction signal is continuously received within the current preset duration and the preset rules, including: the current preset duration is a duration within the preset duration range, and the duration within the preset duration range includes a preset duration lower limit value and a preset duration upper limit value; each switch is also used to adjust the next preset duration according to whether the conduction signal is continuously received within the current preset duration and the preset rules, including: if the switch does not continuously receive the conduction signal within the current preset duration, and the sum of the current preset duration and the fixed preset step length is greater than the upper limit value of the preset duration range, then The next preset duration is equal to the upper limit of the preset duration; if the switch receives the conduction signal continuously within the current preset duration, and the difference between the current preset duration and the fixed preset step length is less than the lower limit of the preset duration range, then the next preset duration is equal to the lower limit of the preset duration; correspondingly, if the switch does not receive the conduction signal continuously within the current preset duration, and the sum of the current preset duration and the fixed preset step length is less than or equal to the upper limit of the preset duration range, then the next preset duration is equal to the sum of the current preset duration and the fixed preset step length; if the switch receives the conduction signal continuously within the current preset duration, and the difference between the current preset duration and the fixed preset step length is greater than or equal to the lower limit of the preset duration range, then the next preset duration is equal to the difference between the current preset duration and the fixed preset step length. In the embodiment of the present application, the upper and lower limits of the preset duration are used to effectively prevent the system from falling into an unstable state due to continuous adjustment, and avoid the safety problems that may be caused by the preset duration being too long or too short. Secondly, the setting of upper and lower limits ensures that the shutdown time always fluctuates within a reasonable range. It will not be adjusted to be too long due to frequent interference, affecting the shutdown efficiency, nor will it be continuously shortened due to no interference to the extent that it affects the stability of the equipment. Finally, by reasonably setting the upper and lower limits, it can adapt to different lighting conditions and load requirements and improve the overall performance and reliability of the photovoltaic system.

[0028] As an optional specific implementation, the fixed preset step length is less than the current preset duration, and the fixed preset step length is greater than or equal to the fixed time period. Further, the fixed preset step length is equal to an integer multiple of the fixed time period. In the embodiment of the present application, the fixed preset step length is less than the current preset duration, thereby preventing the adjustment amplitude from being too large, which is beneficial to the smoothness of the adjustment; the fixed step length is greater than or equal to the fixed time period, so that the preset duration can be effectively fine-tuned, which not only realizes the necessary adjustment function, but also avoids the instability of the system caused by excessive adjustment.

[0029] As an optional specific implementation, there is one-way communication between the transmitter and the photovoltaic switch. Specifically, the transmitter sends a conduction signal, and the photovoltaic switch analyzes and modulates the power line signal to determine whether the conduction signal is received. In the embodiment of the present application, although the photovoltaic system cannot confirm the status of each photovoltaic switch under one-way communication, each photovoltaic switch dynamically adjusts the shutdown time by itself, so that it can adapt to various working conditions and improve the operating stability of the photovoltaic system. As an optional specific implementation, there is two-way communication between the transmitter and the photovoltaic switch. Specifically, the transmitter is a transceiver with the function of receiving and sending signals, and the photovoltaic switch is a photovoltaic switch with the function of sending signals, so that the transmitter can monitor the status of the photovoltaic switch in real time. For example, if the transmitter finds that the shutdown time of a photovoltaic switch has been at the upper limit, then the photovoltaic switch may be abnormal and need maintenance.

[0030] In the embodiment of the present application, the shutdown time of each photovoltaic switch can be adaptively adjusted according to the situation of receiving the conduction signal and the preset rules, so that dynamic adjustment can be achieved regardless of whether it is under harsh working conditions or in an environment with good communication, thereby meeting the dual needs of safe and fast shutdown response. The adaptive adjustment of the shutdown time optimizes the shutdown speed while ensuring safety, thereby improving the performance and reliability of the entire photovoltaic system.

[0031] The implementation process of the shutdown control method provided in the embodiment of the present application is described below. The working process of each device in the photovoltaic system can refer to the working process of the corresponding device in the embodiment of the method. Figure 3 A flow chart of a shutdown control method provided for an embodiment of the present application. The method is applied to a photovoltaic system, which includes an inverter, one or more photovoltaic strings and a transmitter, the photovoltaic strings are connected to the inverter and the transmitter respectively, the inverter is used to convert the direct current output by the photovoltaic strings into alternating current and output it, and the transmitter is used to send a conduction signal to the photovoltaic strings at a fixed time period; each photovoltaic string includes one or more photovoltaic units connected in series, and each photovoltaic unit includes a circuit breaker and one or more photovoltaic components connected to the circuit breaker; the method includes: S1. Receive a conduction signal.

[0032] S2. Determine whether the main switch is turned off according to whether no conduction signal is received continuously within the current preset time length.

[0033] Specifically, if the conduction signal is not received continuously within the current preset time length, the main switch tube is controlled to be turned off. If the conduction signal is received within the current preset time length, the main switch tube is controlled to be turned on.

[0034] S3. Adjust the next preset time length according to whether the conduction signal is continuously received within the current preset time length and the preset rules.

[0035] Specifically, if the circuit breaker does not continuously receive the conduction signal within the current preset time length, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; if the circuit breaker continuously receives the conduction signal within the current preset time length, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

[0036] As an optional specific implementation, the current preset duration is a duration within a preset duration range, and the duration within the preset duration range includes a preset duration lower limit value and a preset duration upper limit value; adjusting the next preset duration according to whether the conduction signal is continuously received within the current preset duration and the preset rule, including: if the conduction signal is not continuously received within the current preset duration, and the sum of the current preset duration and the fixed preset step length is greater than the upper limit value of the preset duration range, then the next preset duration is equal to the preset duration upper limit value; if the conduction signal is continuously received within the current preset duration, and the current preset duration is equal to the fixed preset step length, then the next preset duration is equal to the preset duration upper limit value; Assuming that the difference in step lengths is less than the lower limit of the preset time range, the next preset time length is equal to the lower limit of the preset time length; correspondingly, if the conduction signal is not continuously received within the current preset time length, and the sum of the current preset time length and the fixed preset step length is less than or equal to the upper limit of the preset time range, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; if the conduction signal is continuously received within the current preset time length, and the difference between the current preset time length and the fixed preset step length is greater than or equal to the lower limit of the preset time range, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

[0037] As an optional specific implementation manner, the fixed preset step length is smaller than the current preset duration, and the fixed preset step length is greater than or equal to the fixed time period.

[0038] In an embodiment of the present application, the shutdown time can be adaptively adjusted by receiving a situation-level preset rule of a conduction signal, so that dynamic adjustment can be achieved regardless of whether it is under harsh working conditions or in an environment with good communication, thereby meeting the dual requirements of safe and fast shutdown response.

[0039] It should be understood that Figure 3The order of the steps in the flowchart can be adjusted appropriately, and can also be increased or decreased according to the situation. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 3 At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0040] It should be noted that the photovoltaic system embodiment and the shutdown control method embodiment provided in the embodiments of the present application belong to the same concept; the technical features in the technical solutions recorded in each embodiment can be arbitrarily combined without conflict.

[0041] It should be understood that the above embodiments are exemplary and are not intended to include all possible implementations included in the claims. Various modifications and changes may be made on the basis of the above embodiments without departing from the scope of the present disclosure. Similarly, the various technical features of the above embodiments may be arbitrarily combined to form other embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only express several implementations of the present invention and do not limit the scope of protection of the patent of the present invention.

Claims

1. A photovoltaic system, characterized in that: The photovoltaic system includes an inverter, one or more photovoltaic strings and a transmitter, wherein the photovoltaic strings are connected to the inverter and the transmitter respectively, the inverter is used to convert the direct current output by the photovoltaic strings into alternating current and output it, and the transmitter is used to send a conduction signal to the photovoltaic strings at a fixed time period; each photovoltaic string includes a plurality of photovoltaic units connected in series, each photovoltaic unit includes a circuit breaker and one or more photovoltaic components connected to the circuit breaker; each circuit breaker is used to determine whether the main switch tube of the circuit breaker is turned off according to whether the conduction signal is continuously received within the current preset time length; Each of the switches is further configured to adjust a next preset time duration according to whether the conduction signal is continuously received within the current preset time duration and a preset rule.

2. The photovoltaic system according to claim 1, characterized in that: Each of the switches is further configured to adjust the next preset duration according to whether the conduction signal is continuously received within the current preset duration and a preset rule, including: If the switch does not continuously receive the conduction signal within the current preset time length, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; If the switch continuously receives the conduction signal within the current preset time length, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

3. The photovoltaic system according to claim 1, characterized in that: The current preset duration is a duration within a preset duration range, and the duration within the preset duration range includes a preset duration lower limit value and a preset duration upper limit value; Each of the switches is further configured to adjust the next preset duration according to whether the conduction signal is continuously received within the current preset duration and a preset rule, including: If the switch does not continuously receive the conduction signal within the current preset time length, and the sum of the current preset time length and the fixed preset step length is greater than the upper limit value of the preset time length range, the next preset time length is equal to the preset time length upper limit value; If the switch continuously receives the conduction signal within the current preset time length, and the difference between the current preset time length and the fixed preset step length is less than the lower limit value of the preset time length range, the next preset time length is equal to the lower limit value of the preset time length; Correspondingly, if the switch does not continuously receive the conduction signal within the current preset time length, and the sum of the current preset time length and the fixed preset step length is less than or equal to the upper limit value of the preset time length range, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; If the switch continuously receives the conduction signal within the current preset time length, and the difference between the current preset time length and the fixed preset step length is greater than or equal to the lower limit value of the preset time length range, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

4. The photovoltaic system according to claim 2 or 3, characterized in that: The fixed preset step length is smaller than the current preset duration, and the fixed preset step length is greater than or equal to the fixed time period.

5. The photovoltaic system according to claim 1, characterized in that: Each of the circuit breakers is used to determine whether the main switch tube of the circuit breaker is turned off according to whether the conduction signal is not received continuously within the current preset time length, including: If the circuit breaker fails to receive the conduction signal continuously within the current preset time period, the main switch tube of the circuit breaker is turned off.

6. The photovoltaic system according to claim 5, characterized in that: If the circuit breaker fails to receive the conduction signal continuously within the current preset time, after the main switch of the circuit breaker is turned off, the method further includes: If the circuit breaker receives the conduction signal within the next preset time period, the main switch tube of the circuit breaker is turned on.

7. A shutdown control method, characterized in that: Applied to a photovoltaic system, the photovoltaic system includes an inverter, one or more photovoltaic strings and a transmitter, the photovoltaic strings are connected to the inverter and the transmitter respectively, the inverter is used to convert the direct current output by the photovoltaic strings into alternating current and output it, the transmitter is used to send a conduction signal to the photovoltaic strings at a fixed time period; each of the photovoltaic strings includes one or more photovoltaic units connected in series, each of the photovoltaic units includes a circuit breaker and one or more photovoltaic components connected to the circuit breaker; the method includes: receiving the conduction signal; Determining whether the main switch is turned off according to whether the conduction signal is not received continuously within the current preset time length; The next preset time length is adjusted according to whether the conduction signal is continuously received within the current preset time length and a preset rule.

8. The shutdown control method according to claim 7, characterized in that: Adjusting the next preset time length according to whether the conduction signal is continuously received within the current preset time length and a preset rule includes: If the switch does not continuously receive the conduction signal within the current preset time length, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; If the switch continuously receives the conduction signal within the current preset time length, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

9. The shutdown control method according to claim 7, characterized in that: The current preset duration is a duration within a preset duration range, and the duration within the preset duration range includes a preset duration lower limit value and a preset duration upper limit value; Adjusting the next preset time length according to whether the conduction signal is continuously received within the current preset time length and a preset rule includes: If the conduction signal is not received continuously within the current preset time length, and the sum of the current preset time length and the fixed preset step length is greater than the upper limit of the preset time length range, the next preset time length is equal to the preset time length upper limit; If the conduction signal is continuously received within the current preset time length, and the difference between the current preset time length and the fixed preset step length is less than the lower limit value of the preset time length range, the next preset time length is equal to the lower limit value of the preset time length; Correspondingly, if the conduction signal is not continuously received within the current preset time length, and the sum of the current preset time length and the fixed preset step length is less than or equal to the upper limit value of the preset time length range, the next preset time length is equal to the sum of the current preset time length and the fixed preset step length; If the conduction signal is continuously received within the current preset time length, and the difference between the current preset time length and the fixed preset step length is greater than or equal to the lower limit value of the preset time length range, the next preset time length is equal to the difference between the current preset time length and the fixed preset step length.

10. The shutdown control method according to claim 7, characterized in that: The fixed preset step length is smaller than the current preset duration, and the fixed preset step length is greater than or equal to the fixed time period.

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