Control device, turn-off device and turn-off equipment

Abstract

The invention discloses a control device, a turn-off device and turn-off equipment, and relates to the technical field of photovoltaic equipment, and the control device comprises a first switch module which is used for controlling the on-off state of a bus and an external circuit; the signal output module is electrically connected between the buses and used for outputting an electric signal representing the on-off state of the first switch module to the photovoltaic string circuit, and one end of the signal output module is electrically connected with the input end of the first switch module; the main control switch is used for outputting a main control signal comprising a starting signal and a turn-off signal; and the first control module is electrically connected with the first switch module, the signal output module and the main control switch, and is used for receiving the main control signal and controlling the working states of the first switch module and the signal output module. Electric signals are output to the photovoltaic string through the signal output module, so that the turn-off device in the photovoltaic string can receive the electric signals through the signal receiving device and judge the working state of the control device, and the control device can control the turn-off device.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic equipment, and in particular to a control device, a shutoff device and a shutoff device. Background Art

[0002] A solar photovoltaic power generation system is a power generation system that converts solar radiation energy into electrical energy. It is widely used and is becoming more and more popular because it uses inexhaustible solar energy as energy. A solar photovoltaic power generation system usually consists of several photovoltaic strings and inverter strings, and a photovoltaic string consists of several photovoltaic modules connected in series. A photovoltaic module can consist of a single photovoltaic module or two or more photovoltaic modules connected in series.

[0003] During the power generation process, photovoltaic strings may generate thousands of volts of voltage. Therefore, during the power generation and external output process of photovoltaic strings, if a fire or line abnormality occurs, the photovoltaic strings need to be quickly shut down to facilitate emergency treatment by the staff. The shutdown of photovoltaic strings is divided into component-level shutdown at the component end and string-level shutdown at the inverter end. The photovoltaic system of the prior art usually realizes string-level shutdown intelligently, but there is still DC high voltage in the circuit from photovoltaic components to inverters or controllers, which is a huge hidden danger to personal safety.

[0004] In the prior art, in order to eliminate the high voltage in the circuit from the photovoltaic module to the inverter, a switch is set at the output end of the photovoltaic module, and the operation of the switch is controlled by sending a heartbeat packet to the switch through an external controller, that is, the external controller continuously sends a heartbeat packet to the switch, and the switch remains in the on state when receiving the heartbeat packet, and disconnects the photovoltaic module from the circuit when the heartbeat packet is not received. The defect is that it is necessary to ensure that stable and reliable communication is formed between the switch and the external controller, otherwise it will affect the normal operation of the photovoltaic system and reduce the stability of the system. In addition, the setting distance between the switch and the controller is limited by the communication distance, and the cost is relatively high. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the prior art to a certain extent. To this end, the present invention provides a photovoltaic device, a control device and a shutdown device to accurately and quickly control the connection status of photovoltaic strings and photovoltaic modules.

[0006] In a first aspect, in order to achieve the above-mentioned object, the present invention provides a control device, which is electrically connected to a busbar of a photovoltaic string, wherein the busbar includes a first busbar and a second busbar, wherein the photovoltaic string includes a plurality of photovoltaic modules connected in series, wherein the photovoltaic module includes at least one photovoltaic assembly, and wherein the control device includes:

[0007] A first switch module, electrically connected to the first bus or the second bus, and used to control the on / off state of the bus and an external circuit;

[0008] a signal output module, electrically connected between the first busbar and the second busbar, and used to output an electrical signal representing the on / off state of the first switch module to the photovoltaic string circuit, wherein one end of the signal output module is electrically connected to an input end of the first switch module;

[0009] A main control switch, used for outputting a main control signal including a start signal and a shut-down signal;

[0010] The first control module is electrically connected to the first switch module, the signal output module and the main control switch, and is used to receive the main control signal and control the on / off state of the first switch module, and control the signal output module to switch between at least two different working states.

[0011] In the technical solution, a start signal and a shutdown signal are outputted by the main control switch, and the first control module receives the start signal and the shutdown signal outputted by the main control switch to control the first switch module to operate in an on state or an off state, so that the photovoltaic string is connected or disconnected from the external circuit (inverter). When the photovoltaic string is disconnected from the external circuit, the control signal output module outputs an electrical signal to the photovoltaic string, so that the signal receiving module or the second current detection module in the photovoltaic string receives the electrical signal and determines the connection state between the photovoltaic string and the external circuit according to the electrical parameters of the electrical signal, thereby controlling the connection state between the photovoltaic module and the busbar of the photovoltaic string, and realizing mutual perception of the working state between the shutdown device and the control device without relying on external communication equipment, thereby accurately and quickly controlling the connection state of the photovoltaic string and the line where the photovoltaic module is located.

[0012] Preferably, when the first control module receives the start signal output by the main control switch, it controls the first switch module to work in the on state and controls the signal output module to work in the off state;

[0013] When receiving the shutdown signal output by the main control switch, the first control module controls the first switch module to operate in the shutdown state and controls the signal output module to operate in the on state. When the signal output module operates in the on state, it outputs a preset electrical signal to the photovoltaic string circuit.

[0014] Preferably, when the signal output module is in an on state, it outputs an electrical signal to the photovoltaic string, and the preset electrical signal includes at least one of a voltage signal, a current signal or a waveform signal.

[0015] Preferably, the control device also includes a first voltage detection module, which is electrically connected between the first bus and the second bus, and is used to detect the voltage difference between the first bus and the second bus and generate a first voltage detection signal, an input end of the first voltage detection module is electrically connected to the input end of the first switch module, and an output end of the first voltage detection module is electrically connected to the first control module and outputs the first voltage detection signal to the first control module.

[0016] Preferably, the control device further comprises a first current detection module, which is used to detect the output current of the photovoltaic string and output a first current detection signal representing the output current value of the photovoltaic string to the first control module.

[0017] Preferably, the control device also includes a communication module electrically connected to the first control module, the first control module receives and processes the first voltage detection signal and the first current detection signal, generates working parameter data characterizing the working state of the photovoltaic string, and the first control module interacts with the external device through the communication module, including sending the working parameter data to the external device and receiving control instructions from the external device.

[0018] Preferably, the first control module controls the signal output module to stop working when the current value represented by the first current detection signal is greater than a first current threshold and the voltage difference represented by the first voltage detection signal is greater than a first voltage threshold.

[0019] In a second aspect, to achieve the above-mentioned purpose, the present invention further provides a shut-off device, which is electrically connected to the output end of a photovoltaic module, wherein the photovoltaic module includes at least one photovoltaic assembly, and a plurality of the photovoltaic modules are connected in series to form a photovoltaic string, and a control device as described in any one of the above-mentioned technical solutions is electrically connected to the busbar of the photovoltaic string, wherein the shut-off device includes:

[0020] A second switch module is connected in series to the positive output terminal or the negative output terminal of the photovoltaic module, and is used to control the on-off between the photovoltaic module and the busbar of the photovoltaic string;

[0021] A second current detection module, electrically connected to the output end of the second switch module, for detecting the magnitude of the current flowing through the line where the second current detection module is located and outputting a second current detection signal representing the detected current value;

[0022] A detection circuit, electrically connected between the positive and negative output terminals of the photovoltaic module, and one end of the signal detection circuit is electrically connected between the second switch module and the second current detection module, including a third switch module, when the third switch module is turned on, the signal output module and the second current detection module form a loop;

[0023] The second control module is electrically connected to the second switch module, the third switch module and the second current detection module, receives the second current detection signal, and controls the on / off state of the second switch module and the third switch module based on the second current detection signal.

[0024] Preferably, the signal output module is used to output a fixed current signal, and the second control module controls the second switch module to be disconnected and controls the third switch module to be turned on when the detection current value represented by the second current detection signal is less than or equal to a second current threshold;

[0025] The second control module controls the second switch module to be turned on and controls the third switch module to be turned off when the detection current value represented by the second current detection signal is greater than the second current threshold and less than the third current threshold.

[0026] Preferably, the detection circuit also includes a signal receiving module connected in series with the third switch module, the signal receiving module includes a detection output terminal electrically connected to the second control module, the signal output module is used to output a waveform signal to the photovoltaic string circuit, and the signal receiving module is used to receive the waveform signal and output a waveform parameter detection signal representing the waveform parameters of the waveform signal to the second control module.

[0027] Preferably, the second control module controls the second switch module to be disconnected and controls the third switch module to be turned on when the detection current value represented by the second current detection signal is less than or equal to the second current threshold;

[0028] The second control module controls the second switch module to be turned on and controls the third switch module to be turned off when the waveform parameter detection signal representation signal output module outputs a preset electrical signal.

[0029] Preferably, the shut-off device further comprises a power supply module, the power supply module draws power from the photovoltaic module and is used to supply power to the second control module, and the power supply module comprises a voltage conversion unit.

[0030] Preferably, the power supply module supplies power to the second control module when the output voltage of the photovoltaic module is greater than or equal to a second voltage threshold;

[0031] When the output voltage of the photovoltaic module is less than a third voltage threshold, power supply to the second control module is stopped, and the third voltage threshold is less than the second voltage threshold.

[0032] Preferably, the shutoff device further comprises a freewheeling diode electrically connected between the positive and negative output terminals of the shutoff device.

[0033] In the third aspect, the present invention also proposes a shutdown device for controlling the shutdown of photovoltaic strings and photovoltaic modules in the photovoltaic strings, including a plurality of shutdown devices connected corresponding to the photovoltaic modules and a control device connected to the output end of the photovoltaic string, wherein the shutdown device is set to be a shutdown device as described in any of the above technical solutions, and the control device is set to be a control device as described in any of the above technical solutions.

[0034] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. The best embodiments or means of the present invention will be described in detail in conjunction with the drawings, but they are not intended to limit the technical solutions of the present invention. In addition, there are multiple features, elements, and components that appear in each of the following texts and drawings, and different symbols or numbers are marked for convenience, but they all represent components with the same or similar structures or functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below in conjunction with the accompanying drawings:

[0036] Figure 1 A circuit structure block diagram of a control device according to an embodiment of the present invention;

[0037] Figure 2 is a circuit structure block diagram of another control device according to an embodiment of the present invention;

[0038] Figure 3 A circuit structure block diagram of a shutdown device according to an embodiment of the present invention;

[0039] Figure 4 is a circuit structure block diagram of another shutdown device according to an embodiment of the present invention;

[0040] Figure 5 The figure is a circuit structure block diagram of a shutdown device according to an embodiment of the present invention.

[0041] Description of reference numerals:

[0042] Among them, 10, control device; 11, first control module; 12, first switch module; 13, signal output module; 14, main control switch; 15, first current detection module; 16, first voltage detection module; 17, communication module; 20, shutoff device; 21, second control module; 22, second switch module; 23, second current detection module; 24, third switch module; 25, power supply module; 26, signal receiving module. DETAILED DESCRIPTION

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments in the implementation manner are intended to be used to explain the present invention and should not be construed as limiting the present invention.

[0044] References in this specification to "one embodiment" or "an example" or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment itself may be included in at least one embodiment of the present patent disclosure. The appearance of the phrase "in one embodiment" in various places in the specification does not necessarily refer to the same embodiment.

[0045] like Figure 1 As shown, this embodiment proposes a control device 10, which is electrically connected to the busbar of the photovoltaic string, the busbar includes a first busbar and a second busbar, the photovoltaic string includes a plurality of photovoltaic modules connected in series, the photovoltaic module includes at least one photovoltaic assembly, and the control device 10 includes:

[0046] A first switch module 12, electrically connected to the first bus or the second bus, for controlling the on / off state of the bus and an external circuit;

[0047] A signal output module 13, electrically connected between the first busbar and the second busbar, and used to output an electrical signal representing the on / off state of the first switch module 12 to the photovoltaic string circuit, and one end of the signal output module 13 is electrically connected to the input end of the first switch module 12;

[0048] A main control switch 14, used to output a main control signal including a start signal and a shut-down signal;

[0049] The first control module 11 is electrically connected to the first switch module 12, the signal output module 13 and the main control switch 14, and is used to receive the main control signal and control the on / off state of the first switch module 12, and control the signal output module 13 to switch between at least two different working states.

[0050] In this embodiment, the photovoltaic module is set as a photovoltaic assembly or is composed of two or more photovoltaic assemblies connected in series. The busbar of the photovoltaic string refers to the connection line between the output end of the photovoltaic string and the external circuit. The first busbar is electrically connected between the positive pole of the output end of the photovoltaic string and the positive pole of the input end of the external circuit. The second busbar is electrically connected between the negative pole of the output end of the photovoltaic string and the negative pole of the input end of the external circuit. The external circuit is an electrical device electrically connected to the photovoltaic string, including but not limited to electrical equipment, inverters or energy storage devices electrically connected to the photovoltaic string. In some embodiments, the two different working states of the signal output module 13 include but are not limited to working in an open state and outputting a preset electrical signal and working in an off state and stopping outputting an electrical signal. In other embodiments, when the signal output module 13 works in the open state, it includes outputting a first preset electrical signal when working in the first working state, and outputting a second preset electrical signal when working in the second working state.

[0051] In this embodiment, the main control switch 14 outputs a start signal and a shutdown signal, and the first control module 11 receives the start signal and the shutdown signal output by the main control switch 14 to control the first switch module 12 to operate in an on state or an off state, so that the loop composed of the photovoltaic string and the external circuit (inverter) is turned on or off. When the photovoltaic string is disconnected from the external circuit, the control signal output module 13 operates in an on state and outputs a preset electrical signal to the photovoltaic string, so that the signal receiving module 26 or the second current detection module 23 in the photovoltaic string receives the electrical signal and determines the connection state between the photovoltaic string and the external circuit according to the electrical parameters of the electrical signal, thereby controlling the connection state between the photovoltaic module in the photovoltaic string and the busbar of the photovoltaic string, and realizing mutual perception of the working state between the shutdown device 20 and the control device 10 without relying on external communication equipment, thereby accurately and quickly controlling the connection state of the photovoltaic string and the line where the photovoltaic module is located.

[0052] Specifically, when the first control module 11 receives the start signal output by the main switch 14, it controls the first switch module 12 to work in the on state, and controls the signal output module 13 to work in the off state; when the first control module 11 receives the shut-off signal output by the main switch 14, it controls the first switch module 12 to work in the off state, and controls the signal output module 13 to work in the on state. The main control switch 14 serves as the working control switch of the photovoltaic string circuit. When it is necessary to control the photovoltaic string to be connected to the inverter, the main control switch 14 is controlled to output a start signal. Conversely, when it is necessary to control the photovoltaic string to be disconnected from the inverter, the main control switch 14 is controlled to output a shutdown signal. When the first control module 11 receives the start signal or shutdown signal output by the main control switch 14, it controls the first switch module 12 to be turned on or off accordingly, so as to achieve the connection or disconnection between the photovoltaic string and the inverter. At the same time, when the first control module 11 receives the shutdown signal, it also controls the signal output module 13 to work in the on state to output an electrical signal to the photovoltaic string circuit, so that the shutdown device 20 connected to the output end of the photovoltaic module in the photovoltaic string receives the electrical signal, thereby controlling the on-off state of the second switch module 22 in the shutdown device 20 to be consistent with the on-off state of the first switch module 12 (with signal delay).

[0053] In this embodiment, when the signal output module 13 is in the on state, the preset electrical signal output to the photovoltaic string includes at least one of a voltage signal, a current signal or a waveform signal. In some embodiments, the signal output module 13 includes a signal generating device, which can be a constant current source, a waveform signal generator, or other device for outputting current signals, voltage signals, and waveform signals. It can also include a control device for controlling whether the signal generating device outputs an electrical signal to the photovoltaic string circuit. In this embodiment, the specific form of the control device is not limited. In some embodiments, the signal output module 13 is turned on with a delay after the first switch module 12 is turned off.

[0054] In this embodiment, when the first control module 11 receives the start signal output by the main switch 14, it controls the first switch module 12 to work in the on state, and controls the signal output module 13 to output the first preset electrical signal; when the first control module 11 receives the shut-off signal output by the main switch 14, it controls the first switch module 12 to work in the off state, and controls the signal output module 13 to output the second preset electrical signal. The signal output module 13 in this embodiment can output at least two preset electrical signals with different electrical parameters to correspond to the two working states of the first switch module 12 respectively. In some embodiments, when the signal output module 13 includes a constant voltage source, the signal output module 13 can output voltage signals with two different voltage values, or when the signal output module 13 includes a constant current source, it can output current signals with two different current values, or when the signal output module 13 includes a pulse signal generator, it can output waveform signals with different waveforms (any electrical parameters such as waveform, frequency, phase, amplitude, etc. are not completely the same). So that the shut-off device 20 in the photovoltaic string can detect the current working state of the control device 10.

[0055] like Figure 2 As shown, the control device 10 of this embodiment further includes a first voltage detection module 16, a first current detection module 15 and a communication module 17. The first voltage detection module 16 is electrically connected between the first bus and the second bus and is used to detect the voltage difference between the first bus and the second bus and generate a first voltage detection signal. An input end of the first voltage detection module 16 is electrically connected to the input end of the first switch module 12. The output end of the first voltage detection module 16 is electrically connected to the first control module 11 and outputs the first voltage detection signal to the first control module 11. The first current detection module 15 is used to detect the current output by the photovoltaic string to the external device, and outputs the first current detection signal representing the output current value of the photovoltaic string to the first control module 11. The communication module 17 is electrically connected to the first control module 11. The first control module 11 receives and processes the first voltage detection signal and the first current detection signal, generates working parameter data representing the working state of the photovoltaic string, and the first control module 11 exchanges data with the external device through the communication module 17, including sending the working parameter data to the external device and receiving the control instruction of the external device. The voltage value and current value output by the photovoltaic string to the inverter are detected by the first voltage detection module 16 and the first current detection module 15, and the working parameter data representing the working state of the photovoltaic string can be generated through data processing. The working parameter data can be sent to the external terminal device through the communication module 17 to facilitate monitoring the working state of the photovoltaic string, and the control instructions sent by the external terminal device can be received through the communication module 17. In this embodiment, the external device is a device that can communicate with the communication module 17, including but not limited to a computer, a server, a mobile terminal or an Internet of Things control terminal.

[0056] Specifically, the first control module 11 controls the signal output module 13 to work in a closed state when the current value represented by the first current detection signal is greater than the first current threshold value and the bus voltage difference represented by the first voltage detection signal is greater than the first voltage threshold value. In this embodiment, the first current threshold value is usually set according to the minimum output current value of the photovoltaic string when it is working, and the first voltage threshold value is set according to the minimum output voltage value of the photovoltaic string when it is working. The current on the output bus of the photovoltaic string is greater than the first current threshold value and the voltage is greater than the first voltage threshold value, indicating that the circuit in the photovoltaic string is normally turned on and starts to work normally. At this time, in order to reduce the risk of circuit failure and energy consumption and ensure the normal operation of the circuit, the signal output module 13 is controlled to work in a closed state.

[0057] like Figure 3 As shown, this embodiment further provides a shut-off device 20, which is electrically connected to the output end of the photovoltaic module, the photovoltaic module includes at least one photovoltaic assembly, and a plurality of the photovoltaic modules are connected in series to form a photovoltaic string, and the photovoltaic string bus is electrically connected to a control device 10 as described in any of the above technical solutions, and the shut-off device 20 includes:

[0058] A second switch module 22, connected in series to the positive output terminal or the negative output terminal of the photovoltaic module, for controlling the on-off between the photovoltaic module and the busbar of the photovoltaic string;

[0059] A second current detection module 23, electrically connected to the output end of the second switch module 22, for detecting the magnitude of the current flowing through the line where it is located and outputting a second current detection signal representing the detected current value;

[0060] A detection circuit, electrically connected between the positive and negative output terminals of the photovoltaic module, and one end of the signal detection circuit is electrically connected between the second switch module 22 and the second current detection module 23, including a third switch module 24, when the third switch module 24 is turned on, the signal output module 13 and the second current detection module 23 form a loop;

[0061] The second control module 21 is electrically connected to the second switch module 22, the third switch module 24 and the second current detection module 23, receives the second current detection signal, and controls the on / off state of the second switch module 22 and the third switch module 24 based on the second current detection signal.

[0062] In this embodiment, a detection circuit and a second current detection module 23 are provided so as to form a loop with the signal output module 13 of the control device 10. When the second switch module 22 and the first switch module 12 are disconnected, the loop formed by the detection circuit, the second current detection module 23 and the signal output module 13 of the control device 10 is turned on, and the current signal output by the signal output module 13 is received by the second current detection module 23, and a second current detection signal is generated and sent to the second control module 21. The second control module 21 receives the second current detection signal to determine the working state of the control device 10 and the on-off (on or off) state of the first switch module 12, and then controls the on-off state of the second switch module 22 so that the on-off state of the second switch module 22 is consistent with the on-off state of the first switch module 12. That is, when the first switch module 12 of the control device 10 is turned off, the second switch module 22 at the output end of the photovoltaic module is turned off synchronously, and when the first switch module 12 of the control device 10 is turned on, the second switch module 22 at the output end of the photovoltaic module is turned on synchronously, so as to prevent the potential safety hazard caused by the presence of high voltage in the photovoltaic string when the photovoltaic string is disconnected from the inverter. The synchronous shutdown described in this embodiment does not mean that the shutdown time is exactly the same, but means that after the switching action of the first switch module 12 is detected, the switching action of the second switch module 22 is controlled accordingly, and there is a certain signal delay between the switching actions of the two switch modules.

[0063] As an implementation method, the signal output module 13 is used to output a fixed current signal, and the second control module 21 controls the second switch module 22 to disconnect and controls the third switch module 24 to turn on when the detection current value represented by the second current detection signal is less than or equal to the second current threshold; the second control module 21 controls the second switch module 22 to turn on and controls the third switch module 24 to disconnect when the detection current value represented by the second current detection signal is greater than the second current threshold and less than the third current threshold. In this embodiment, the second current detection device can be used to assist in determining the on / off state of the first switch module 12 in the control device 10, wherein the second current threshold is usually set to a number close to zero. When the detection current value represented by the second current detection signal is less than or equal to the second current threshold, it indicates that the photovoltaic string circuit and the inverter are disconnected or the photovoltaic module has no current output. At this time, the second switch module 22 is controlled to be disconnected and the third switch module 24 is controlled to be turned on, so that the photovoltaic module does not output voltage to the string and the second current detection module 23 and the signal output module 13 form a loop, so that the second current detection module 23 can detect the change in the current output by the signal output module 13 to the circuit in which it is located, and then determine the on state of the first switch module 12; the third current threshold is set based on the current output by the signal output module 13 to the second current detection module 23 when the signal output module 13 and the second current detection module 23 form a loop and the first switch module 12 is turned on. After the first switch module 12 and the second switch module 22 are both disconnected and the third switch module 24 is turned on, the signal output module 13 (constant current source) and the plurality of third switch modules 24 in the photovoltaic string and the plurality of second current detection modules 23 form a loop. At this time, the detection current value of the second current detection module 23 is equal to the output current value of the constant current source. For example, if the output current of the signal output module 13 is I1, the detection current value of the second current detection module 23 is also I1. If the first switch module 12 is turned on at this time, the signal output module 13, the first switch module 12 and the primary side of the external circuit (inverter) form a second loop. When the output current remains unchanged, the current flowing through the second current detection module 23 is shunted due to the conduction of the first switch module 12. At this time, the detection current value of the second current detection module 23 will be less than I1. In an exemplary embodiment, when there is no other fault in the circuit, the detection current value of the second current detection module 23 is I2, and the third current threshold is set to a value greater than I2 and less than I1, for example, set to 1.1 times I2. When the second control module 21 receives a second current detection signal indicating that the current value is greater than 0 and less than 1.1·I2, the second switch module 22 is controlled to be turned on and the third switch module 24 is turned off.

[0064] As another implementation, Figure 4As shown, the detection circuit also includes a signal receiving module 26 connected in series with the third switch module 24, the detection output end of the signal receiving module 26 is electrically connected to the second control module 21, the signal output module 13 is used to output a waveform signal to the photovoltaic string circuit, and the signal receiving module 26 is used to receive the waveform signal and output a waveform parameter detection signal representing the waveform parameters of the waveform signal to the second control module 21. By setting the signal receiving module 26 in the detection circuit to receive the waveform signal output by the signal output module 13, the waveform signal is detected by the signal receiving module 26 and a waveform parameter detection signal is generated, and the waveform parameter detection signal is sent to the second control module 21. The second control module 21 determines the working state of the signal output module 13 by analyzing and processing the waveform parameter detection signal, and then determines the on-off state of the first switch module 12.

[0065] Specifically, the second control module 21 controls the second switch module 22 to be disconnected and the third switch module 24 to be turned on when the detection current value represented by the second current detection signal is less than or equal to the second current threshold; the second control module 21 controls the second switch module 22 to be turned on and controls the third switch module 24 to be turned off when the signal output module 13 represented by the waveform parameter detection signal outputs a preset electrical signal. In the above technical solution, when the first switch module 12 is turned on, the second control module 21 detects the disconnection action of the first switch module 12 through the second current detection signal output by the second current detection module 23; when the first switch module 12 is turned off, the second control module 21 detects the turn-on action of the first switch module 12 through the waveform parameter detection signal output by the signal receiving module 26. In the above, the second control module 21 realizes the detection of the conduction state of the first switch module 12, and by controlling the second switch module 22 to have the same conduction state as the first switch module 12, the purpose of the present application is achieved.

[0066] Specifically, Figure 3 As shown in Figure 4, the shutdown device 20 also includes a power module 25, which takes power from the photovoltaic module and is used to supply power to the second control module 21. The power module 25 includes a voltage conversion unit, and the voltage conversion unit is set as a DC-DC direct current conversion circuit to convert the wide-range direct current voltage signal output by the photovoltaic module into a fixed voltage signal. The shutdown device 20 also includes a freewheeling diode D1 electrically connected between the positive and negative output terminals of the shutdown device 20. The freewheeling diode D1 is used to ensure that when any photovoltaic module or the shutdown device 20 in the photovoltaic string circuit is disconnected due to abnormal operation, the remaining photovoltaic modules in the photovoltaic string can still output power to the inverter normally to ensure the normal operation of the photovoltaic string.

[0067] Specifically, the power module 25 supplies power to the second control module 21 when the output voltage of the photovoltaic module is greater than or equal to the second voltage threshold; and stops supplying power to the second control module 21 when the output voltage of the photovoltaic module is less than a third voltage threshold, wherein the third voltage threshold is less than the second voltage threshold. In some embodiments, the third voltage threshold is set based on the minimum voltage for normal operation of the power module 25, and the second voltage threshold is higher than the third threshold voltage. For example, the second voltage threshold is set to 8V, and the third voltage threshold is set to 5V. When the output voltage of the photovoltaic module is greater than 8V, the power module 25 starts to work, and when the output voltage of the photovoltaic module is less than 5V, the power module 25 stops working. The above setting can prevent the photovoltaic module from being frequently started and stopped when the output voltage of the photovoltaic module is unstable and fluctuates near its operating voltage.

[0068] Exemplarily, the first circuit detection module and the second current detection module 23 include a Hall current sensor, and the first switch module 12, the second switch module 22 and the third switch module 24 are set to be one of a MOS tube, an IGBT or a relay switch. It should be noted that this embodiment does not limit the model and type of the above-mentioned switch modules, and can be set to any switch device that can achieve the purpose of the present invention.

[0069] like Figure 5 As shown, the present invention also proposes a shutdown device for controlling the shutdown of photovoltaic strings and photovoltaic modules in the photovoltaic strings, including a plurality of shutdown devices 20 connected to the photovoltaic modules and a control device 10 connected to the output end of the photovoltaic string, wherein the shutdown device 20 is configured as the shutdown device 20 described in any one of the above technical solutions, and the control device 10 is configured as the control device 10 described in any one of the above technical solutions.

[0070] When in use, during the startup process, the main control switch 14 is controlled to output a startup signal, the first control module 11 of the control device 10 controls the first switch module 12 to be turned on, the control signal output module 13 outputs a first preset electrical signal to the photovoltaic string circuit, and the signal receiving module or the second current detection module 23 of the shutdown device 20 receives the preset electrical signal output by the signal output module 13 and sends a corresponding detection signal to the second control module 21. After receiving the detection signal representing that the signal output module 13 outputs the first preset electrical signal, the second control module 21 controls the second switch module 22 to be turned on and the third switch module 24 to be turned off; during the shutdown process, the main control switch 14 is controlled to output a shutdown signal, the first control module 11 of the control device 10 controls the first switch module 12 to be turned off, the control signal output module 13 outputs a second preset electrical signal to the photovoltaic string circuit or works in a closed state, and when the current flowing through the second current detection module 23 of the shutdown device 20 changes (to 0), the second control module 21 controls the second switch module 22 to be turned off and controls the third switch module 24 to be closed. The control device 10 further includes a first control module 11 that receives a first current detection signal and a first voltage detection signal to determine whether the photovoltaic string circuit is working normally, and disconnects the first control switch when an abnormal signal is detected. The shutdown device of this embodiment detects changes in electrical parameters in the photovoltaic string circuit, thereby realizing mutual perception and linkage of the working status between the shutdown device 20 and the control device 10. The shutdown device of this embodiment can realize component-level shutdown control without setting up additional communication equipment, and the control process is more stable, accurate, and fast, which improves control stability and accuracy while saving manufacturing costs.

[0071] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A control device, electrically connected to a busbar of a photovoltaic string, wherein the busbar includes a first busbar and a second busbar, wherein the photovoltaic string includes a plurality of photovoltaic modules connected in series, wherein the photovoltaic module includes at least one photovoltaic assembly, wherein: The control device comprises: A first switch module (12), electrically connected to the first busbar or the second busbar, and used to control the on / off state of the busbar and an external circuit; A signal output module (13) is electrically connected between the first busbar and the second busbar, and is used to output an electrical signal representing the on / off state of the first switch module (12) to the photovoltaic string circuit, and one end of the signal output module (13) is electrically connected to an input end of the first switch module (12); A main control switch (14), used for outputting a main control signal including a start signal and a shut-down signal; A first control module (11) is electrically connected to the first switch module (12), the signal output module (13) and the main control switch (14), and is used to receive the main control signal and control the on / off state of the first switch module (12), and control the signal output module (13) to switch between at least two different working states.

2. The control device according to claim 1, characterized in that: When receiving a start signal output by the main control switch (14), the first control module (11) controls the first switch module (12) to operate in an on state, and controls the signal output module (13) to operate in an off state; When receiving a shutdown signal output by the main control switch (14), the first control module (11) controls the first switch module (12) to operate in an off state, and controls the signal output module (13) to operate in an on state; when the signal output module (13) operates in the on state, it outputs a preset electrical signal to the photovoltaic string circuit.

3. The control device according to claim 2, characterized in that: When the signal output module (13) is in an on state, it outputs an electrical signal to the photovoltaic string, wherein the preset electrical signal comprises at least one of a voltage signal, a current signal or a waveform signal.

4. The control device according to any one of claims 1 to 3, characterized in that: The control device further comprises a first voltage detection module (16), the first voltage detection module (16) being electrically connected between the first busbar and the second busbar, and being used to detect a voltage difference between the first busbar and the second busbar and to generate a first voltage detection signal, an input end of the first voltage detection module (16) being electrically connected to an input end of the first switch module (12), and an output end of the first voltage detection module (16) being electrically connected to the first control module (11) and outputting the first voltage detection signal to the first control module (11).

5. The control device according to claim 4, characterized in that: The control device further comprises a first current detection module (15), wherein the first current detection module (15) is used to detect the output current of the photovoltaic string and output a first current detection signal representing the output current value of the photovoltaic string to the first control module (11).

6. The control device according to claim 5, characterized in that: The control device further comprises a communication module (17) electrically connected to the first control module (11); the first control module (11) receives and processes the first voltage detection signal and the first current detection signal to generate operating parameter data representing the operating state of the photovoltaic string; the first control module (11) performs data exchange with an external device via the communication module (17), including sending the operating parameter data to the external device and receiving control instructions from the external device.

7. The control device according to claim 6, characterized in that: The first control module (11) controls the signal output module (13) to stop working when the current value represented by the first current detection signal is greater than a first current threshold and the voltage difference represented by the first voltage detection signal is greater than a first voltage threshold.

8. A shut-off device electrically connected to an output terminal of a photovoltaic module, wherein the photovoltaic module comprises at least one photovoltaic component, characterized in that: A plurality of the photovoltaic modules are connected in series to form a photovoltaic string, a busbar of the photovoltaic string is electrically connected to a control device as described in any one of claims 1 to 7, and the shutdown device comprises: A second switch module (22) is connected in series to the positive output terminal or the negative output terminal of the photovoltaic module and is used to control the on / off between the photovoltaic module and the busbar of the photovoltaic string; A second current detection module (23), electrically connected to the output end of the second switch module (22), for detecting the magnitude of the current flowing through the line on which it is located and outputting a second current detection signal representing the detected current value; A detection circuit is electrically connected between the positive and negative output terminals of the photovoltaic module, and one end of the signal detection circuit is electrically connected between the second switch module (22) and the second current detection module (23), and includes a third switch module (24). When the third switch module (24) is turned on, the signal output module (13) and the second current detection module (23) form a loop; A second control module (21) is electrically connected to the second switch module (22), the third switch module (24) and the second current detection module (23), receives the second current detection signal, and controls the on / off state of the second switch module (22) and the third switch module (24) based on the second current detection signal.

9. The shutoff device according to claim 8, characterized in that: The signal output module (13) is used to output a fixed current signal, and the second control module (21) controls the second switch module (22) to be disconnected and controls the third switch module (24) to be turned on when the detection current value represented by the second current detection signal is less than or equal to a second current threshold; The second control module (21) controls the second switch module (22) to be turned on and controls the third switch module (24) to be turned off when the detection current value represented by the second current detection signal is greater than the second current threshold and less than the third current threshold.

10. The shutoff device according to claim 8, characterized in that: The detection circuit further comprises a signal receiving module (26) connected in series with the third switch module (24), the signal receiving module (26) comprising a detection output terminal electrically connected to the second control module (21), the signal output module (13) being used to output a waveform signal to the photovoltaic string circuit, and the signal receiving module (26) being used to receive the waveform signal and output a waveform parameter detection signal to the second control module (21).

11. The shutoff device according to claim 10, characterized in that: The second control module (21) controls the second switch module (22) to be disconnected, the third switch module (24) to be turned on, and controls the signal receiving module (26) to start working when the detection current value represented by the second current detection signal is less than or equal to a second current threshold; When the waveform parameter detection signal indicates that the signal output module (13) outputs a preset electrical signal, the second control module (21) controls the second switch module (22) to be turned on, the third switch module (24) to be turned off, and the signal receiving module (26) to stop working.

12. The shutoff device according to any one of claims 8 to 11, characterized in that: The shutoff device further comprises a power module (25), the power module (25) draws power from the photovoltaic module and is used to supply power to the second control module (21), and the power module (25) comprises a voltage conversion unit.

13. The shutoff device according to claim 12, characterized in that: The power supply module (25) supplies power to the second control module when the output voltage of the photovoltaic module is greater than or equal to a second voltage threshold; When the output voltage of the photovoltaic module is less than a third voltage threshold, power supply to the second control module is stopped, and the third voltage threshold is less than the second voltage threshold.

14. The shutoff device according to any one of claims 8 to 11, characterized in that: The shutoff device also includes a freewheeling diode electrically connected between the positive and negative output terminals of the shutoff device.

15. A shutdown device for controlling the shutdown of a photovoltaic string and a photovoltaic module in the photovoltaic string, characterized in that: The invention comprises a plurality of shut-off devices (20) connected to the photovoltaic modules and a control device (10) connected to the output end of the photovoltaic string, wherein the control device (10) is configured as a control device (10) as described in any one of claims 1 to 7, and the shut-off device (20) is configured as a shut-off device (20) as described in any one of claims 8 to 14.

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