Photovoltaic equipment and rapid turn-off device thereof

Abstract

The utility model discloses a photovoltaic device and a rapid turn-off device thereof, the rapid turn-off device is electrically connected between a photovoltaic module and an inverter, and the rapid turn-off device comprises a first control unit, and at least one switch circuit and at least one detection unit which are respectively communicated with the first control unit; the switching circuit is used for connecting and disconnecting the electrical connection between the photovoltaic module and the inverter; the detection unit acquires a pulsating current signal at one end, electrically connected with the inverter, of the switching circuit; the first control unit receives the pulsating current signal from the detection unit and sends a switching control signal to the switching circuit. According to the utility model, whether the photovoltaic module and the rapid turn-off device work normally can be detected and identified, the photovoltaic output is correspondingly adjusted, a central controller and a coupling coil are not needed, and the device has the advantages of low cost, high reliability and the like.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic control technology, and in particular to a photovoltaic device and its fast shutdown device. Background Technology

[0002] Rooftop photovoltaic (PV) systems are devices installed on the roof of buildings to convert solar energy into electrical energy. Their core components include photovoltaic modules and inverters. NEC 690 is a standard for electrical, electronic, and communication systems in buildings or structures. Based on the requirements of the NEC 690 standard, rooftop PV systems must be equipped with a Rapid Shutdown Device (RSD). When the RSD activates, the output voltage of the rooftop PV system must quickly drop below a safe voltage to prevent firefighters from suffering electric shock.

[0003] Existing technologies have the following problems: A central controller and its coupling coil need to be added outside the fast shutdown device to control the on / off state of the fast shutdown device, increasing product costs; the central controller continuously sends signals while the photovoltaic system is operating, increasing standby power consumption; the system can only send signals unidirectionally to control the RSD to open or close, and cannot detect the status of the RSD and photovoltaic modules, such as whether the photovoltaic modules are powered or whether there is a system fault. Furthermore, sending signals via coil coupling is prone to interference and false triggering. Utility Model Content

[0004] This utility model provides a photovoltaic device and its fast shutdown device. By adding a switching circuit and a detection unit to the fast shutdown device to adjust the on / off state of the fast shutdown device, it solves the problems of existing fast shutdown devices that use a central controller and coil coupling to send signals to trigger on / off control, which leads to increased product cost and energy consumption, inability to detect the system working status, and easy interference and false triggering of the trigger signal.

[0005] According to one aspect of this utility model, a fast shutdown device is provided, applied to a photovoltaic device, the photovoltaic device including at least one photovoltaic module and at least one inverter, the fast shutdown device being electrically connected between the photovoltaic module and the inverter. The fast shutdown device includes: a first control unit, and at least one switching circuit and at least one detection unit communicating with the first control unit. The switching circuit is used to connect and disconnect the electrical connection between the photovoltaic module and the inverter. The detection unit collects a pulsating current signal at the end of the switching circuit electrically connected to the inverter. The first control unit receives the pulsating current signal from the detection unit and sends a switching control signal to the switching circuit.

[0006] Optionally, the switching circuit includes a DC-DC buck converter circuit. The DC-DC buck converter circuit includes a main switching device, a freewheeling device, a filter device, and an energy storage device. One current terminal of the main switching device is electrically connected to the positive terminal of the photovoltaic module, and the other current terminal is electrically connected to one end of the filter device. The control terminal of the main switching device communicates with the first control unit. One current terminal of the freewheeling device is electrically connected to the negative terminal of the photovoltaic module, and the other current terminal is electrically connected to the filter device, which is electrically connected to the main switching device. One current terminal of the energy storage device is electrically connected to the negative terminal of the photovoltaic module, and the other current terminal is electrically connected to the filter device, which is electrically connected to the inverter.

[0007] Optionally, the detection unit includes any one of the following: a current transformer, a detection resistor, a shunt, a Hall sensor, and an inductor coil.

[0008] Optionally, the main switching device is a through-type switching transistor or a pulse-driven switching transistor.

[0009] Optionally, the freewheeling device is a freewheeling diode.

[0010] Optionally, the freewheeling device includes any one of the following: MOS transistor (Metal-Oxide-Semiconductor Field-Effect Transistor), IGBT transistor (Insulated Gate Bipolar Transistor), or thyristor.

[0011] Optionally, the freewheeling device includes a control terminal, which communicates with the first control unit.

[0012] Optionally, the fast shutdown device further includes: a second control unit, which is set independently or integrated with the inverter; the second control unit receives voltage signals or current signals from the first control unit.

[0013] Optionally, the fast shutdown device further includes a communication unit, which communicates with the first control unit and the terminal device respectively. The communication unit receives instruction information from the terminal device and sends the received instruction information to the first control unit.

[0014] According to another aspect of the present invention, a photovoltaic device is provided, comprising: at least one photovoltaic module, at least one inverter, and any one of the above-mentioned fast shutdown devices.

[0015] The technical solution of this utility model embodiment involves the detection unit collecting pulsating current signals at the end of the switching circuit electrically connected to the inverter. This allows the first control unit to determine whether the electrical connection between the photovoltaic module and the inverter needs to be turned on or off based on the pulsating current signal, and then send a switching control signal to the switching circuit to control it. Therefore, compared with the prior art, the fast shutdown device in this utility model embodiment does not require a central controller and coupling coil, and has advantages such as low cost, low loss, and high reliability.

[0016] The technical solution of this utility model embodiment requires very few components for the switching circuit, is reliable in operation, and has advantages such as low cost, low loss, and low interference.

[0017] The technical solution of this embodiment of the invention involves the second control unit receiving voltage or current signals from the first control unit. The second control unit can calculate the total voltage value at the inverter input terminal based on the received voltage or current signals, and determine whether an alarm needs to be issued based on the calculated total voltage value. Therefore, this technical solution can identify the operating status of the entire photovoltaic equipment and promptly troubleshoot faults.

[0018] The technical solution of this embodiment of the utility model involves communication between the communication unit and the first control unit and the terminal device, respectively. The communication unit receives instruction information from the terminal device and sends the received instruction information to the first control unit. Therefore, this technical solution enables remote control of the fast shutdown device, which helps to avoid dangers such as fire and electric shock during troubleshooting.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A circuit topology diagram of a fast shutdown device provided for an embodiment of this utility model;

[0022] Figure 2 A circuit topology diagram of a switching circuit provided for an embodiment of this utility model;

[0023] Figure 3 A circuit topology diagram of another switching circuit provided for an embodiment of this utility model;

[0024] Figure 4 A circuit topology diagram of another fast shutdown device provided in an embodiment of this utility model;

[0025] Figure 5 A circuit topology diagram of another fast shutdown device provided in this embodiment of the utility model;

[0026] Figure 6 This is a schematic diagram of the circuit topology of a photovoltaic device provided for an embodiment of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] Figure 1 This is a circuit topology diagram of a fast shutdown device provided in an embodiment of the present invention. This embodiment is applicable to application scenarios where photovoltaic equipment is powered off quickly. For example, the fast shutdown device 3 can reduce the voltage of the photovoltaic module 1 from a distance of one foot to a safe voltage (e.g., below 30V) within a short time (e.g., 30 seconds).

[0030] like Figure 1As shown, the photovoltaic device of this application includes two photovoltaic modules 1, an inverter 2, and a fast shutdown device 3. It should be understood that, in possible implementations, the photovoltaic device may include multiple photovoltaic modules 1, an inverter 2, and multiple fast shutdown devices 3 electrically connected between each photovoltaic module 1 and the inverter 2. That is, the photovoltaic device may include multiple photovoltaic channels, each with one photovoltaic module 1 and one fast shutdown device 3, and all multiple photovoltaic channels are electrically connected to the inverter 2.

[0031] exist Figure 1 In the illustrated embodiment, a fast shutdown device 3 is electrically connected between the photovoltaic module 1 and the inverter 2. The fast shutdown device 3 includes a first control unit 310, and at least one switching circuit 320 and at least one detection unit 330, both communicating with the first control unit 310. The switching circuit 320 is used to connect and disconnect the electrical connection between the photovoltaic module 1 and the inverter 2. The detection unit 330 collects a pulsating current signal at the end of the switching circuit 320 electrically connected to the inverter 2. The first control unit 310 receives the pulsating current signal from the detection unit 330 and sends a switching control signal to the switching circuit 320. By collecting the pulsating current signal at the end of the switching circuit 320 electrically connected to the inverter 2, the first control unit 310 can determine whether to connect or disconnect the electrical connection between the photovoltaic module 1 and the inverter 2 based on the pulsating current signal, and send a switching control signal to the switching circuit 320 to control the switching circuit 320.

[0032] exist Figure 1 In the illustrated embodiment, one input terminal of the switching circuit 320 is connected to the positive terminal of the photovoltaic module 1, and the other input terminal of the switching circuit 320 is connected to the negative terminal of the photovoltaic module 1. One output terminal of the switching circuit 320 is connected to the PV+ terminal of the inverter 2, and the other output terminal of the switching circuit 320 is connected to the PV- terminal of the inverter 2. The switching circuit 320 is controlled by the first control unit 310. When the first control unit 310 controls the switching circuit 320 to be turned on, the photovoltaic module 1 outputs electrical energy to the inverter 2; when the first control unit 310 controls the switching circuit 320 to be turned off, the photovoltaic module 1 stops outputting electrical energy to the inverter 2.

[0033] The detection unit 330 is used to acquire electrical signals from the switching circuit 320. Optionally, the electrical signals include, but are not limited to, pulsating current signals, voltage signals (which may be the voltage value of one photovoltaic output terminal), and current signals (which may be the current value of one photovoltaic output terminal) at the output terminal of the switching circuit 320.

[0034] Taking the transition of the fast shutdown device 3 from standby state (switch circuit 320 disconnected) to working state (switch circuit 320 closed) as an example, the process of the first control unit 310 controlling the switch circuit 320 is as follows: If the photovoltaic module 1 or the fast shutdown device 3 is damaged, the corresponding photovoltaic circuit has no output voltage. In this case, it is not necessary to switch the fast shutdown device 3 from standby state to working state, that is, it is not necessary to close the switch circuit 320. When both the photovoltaic module 1 and the fast shutdown device 3 are working normally, the standby voltage is output from the switch circuit 320 of the fast shutdown device 3. The detection unit 330 collects the pulsating current signal at the end of the switch circuit 320 that is electrically connected to the inverter 2. After receiving the pulsating current signal, the first control unit 310 analyzes whether the pulsating current signal meets the preset. When the pulsating current signal meets the preset, the first control unit 310 sends a switch control signal to the switch circuit 320, causing the switch circuit 320 to close, the fast shutdown device 3 to enter the working state from the standby state, the electrical connection between the photovoltaic module 1 and the inverter 2 is established, and the working voltage is output to the inverter 2. When the pulsating current signal does not meet the preset condition, the fast shutdown device 3 remains in standby mode.

[0035] In some embodiments, the design value of the standby voltage output from the fast shutdown device 3 depends on the maximum number of photovoltaic modules 1 that can be installed on-site. In one possible implementation, the design value of the standby voltage is less than the voltage value obtained by dividing the safe voltage of 30V by the maximum number of photovoltaic modules 1 that can be installed on-site, ensuring that the total voltage at the input of the inverter 2 is less than the safe voltage during standby.

[0036] In summary, the technical solution of this utility model embodiment features a fast shutdown device 3 with a built-in switching circuit 320 and a detection unit 330. The switching on / off control is triggered by the electrical signal detected by the detection unit 330, eliminating the need for a central controller and coupling coil. This design offers advantages such as low cost and high reliability. When the photovoltaic module 1 is powered, the switching circuit 320 outputs a standby voltage, with energy derived from the photovoltaic module 1. This eliminates the need to consume energy from the inverter 2 (or the power grid), thus avoiding additional energy loss.

[0037] Figure 2 A circuit topology diagram of a switching circuit provided in an embodiment of this utility model. Figure 3 A schematic diagram of another switching circuit topology provided for an embodiment of this utility model.

[0038] See Figure 2 and Figure 3As shown, the switching circuit 320 includes a DC-DC buck converter circuit. This DC-DC buck converter circuit includes a main switching device, a freewheeling device, a filter device, and an energy storage device. One current terminal of the main switching device is electrically connected to the positive terminal of the photovoltaic module 1, and the other current terminal is electrically connected to one end of the filter device. The control terminal of the main switching device communicates with the first control unit 310. One current terminal of the freewheeling device is electrically connected to the negative terminal of the photovoltaic module 1, and the other current terminal is electrically connected to the filter device, which is electrically connected to one end of the main switching device. One current terminal of the energy storage device is electrically connected to the negative terminal of the photovoltaic module 1, and the other current terminal is electrically connected to the filter device, which is electrically connected to one end of the inverter 2.

[0039] The detection unit 330 includes any one of the following: a current transformer, a sensing resistor, a shunt, a Hall sensor, and an inductor coil. Preferably, the detection unit 330 employs a current transformer (CT1 to CTn).

[0040] In possible implementations, the switching circuit 320 may also be a DC-DC boost converter circuit or a DC-DC buck-boost converter circuit.

[0041] In possible implementations, the main switching device is a pass-through switching transistor or a pulse-driven switching transistor, for example... Figure 2 , Figure 3 The diagram illustrates Q1 to Qn. A direct-acting switch is one that is always on. A pulse-driven switch is one that is turned on and off by a pulse signal (such as a PWM signal). Preferably, the switching circuit 320 can be a DC-DC buck converter circuit to reduce circuit cost.

[0042] In a possible implementation, the freewheeling device is a freewheeling diode, for example... Figure 2 The diagram shows D1 to Dn.

[0043] In a possible implementation, the freewheeling device is any one of the following: MOS (Metal-Oxide-Semiconductor Field-Effect Transistor), IGBT (Insulated Gate Bipolar Transistor), or thyristor.

[0044] In a possible implementation, the freewheeling device includes a control terminal, for example... Figure 3 The diagram shows Q21 to Q2n. The control terminal of the freewheeling device communicates with the first control unit 310 and is controlled by the first control unit 310 to switch between closed and open states.

[0045] Figure 4 A circuit topology diagram of another fast shutdown device provided in an embodiment of this utility model. Figure 4In the illustrated embodiment, the fast shutdown device 3 further includes a second control unit 340, which may be independently configured or integrated with the inverter 2. The second control unit 340 receives voltage signals (which may be voltage values) or current signals (which may be current values) from the first control unit 310. The second control unit 340 calculates the total voltage value at the input terminal of the inverter 2 based on all received voltage or current signals, and determines whether an alarm needs to be issued based on the calculated total voltage value.

[0046] In a possible implementation, the photovoltaic device includes n photovoltaic channels, where n is greater than or equal to 2. The voltage signal received by the second control unit 340 from the first control unit 310 is the standby voltage output when the fast shutdown device 3 remains in standby mode. The second control unit 340 calculates the total voltage value by summing each received standby voltage; the summed voltage value is the total voltage value at the input of the inverter 2 under the current condition. If the calculated total voltage value is equal to the sum of the standby voltages of the n photovoltaic channels included in the photovoltaic device, no alarm is required. If the total voltage value calculated by the second control unit 340 is greater than or less than the sum of the standby voltages of the n photovoltaic channels included in the photovoltaic device, an alarm is required. In a possible implementation, the standby voltages set for each of the n photovoltaic channels are not all equal; in this case, the sum of the standby voltages set for the n photovoltaic channels included in the photovoltaic device can be preset as a comparison voltage value. In another possible implementation, the standby voltages set for each photovoltaic channel are equal; the standby voltages set for the n photovoltaic channels included in the photovoltaic device can be multiplied by n and preset as a comparison voltage value.

[0047] Figure 5 This is a circuit topology diagram of another fast shutdown device provided in an embodiment of the present invention. Figure 5 In the illustrated embodiment, the fast shutdown device 3 further includes a communication unit 350. The communication unit 350 communicates with both the first control unit 310 and a terminal device (not shown). Typically, the terminal device includes, but is not limited to, smartphones, smart wearable devices, laptops, and desktop computers. The communication unit 350 receives instruction information from the terminal device and sends the received instruction information to the first control unit 310. When the photovoltaic equipment is operating, maintenance personnel can set the number n of photovoltaic modules 1 and the preset safety voltage on the terminal device. The terminal device sends the received data to the first control unit 310 based on wireless or wired communication technology. The first control unit 310 configures the standby voltage of the fast shutdown device 3 for each photovoltaic module according to the number n of photovoltaic modules 1 and the preset safety voltage. Figure 5 The technical solution in the illustrated embodiment enables remote control of the rapid shutdown device 3, which helps to avoid dangers such as fire and electric shock during the troubleshooting process.

[0048] Based on the above embodiments, this utility model also provides a photovoltaic device.

[0049] See Figure 6 As shown, Figure 6 This is a circuit topology diagram of a photovoltaic device provided in an embodiment of the present invention. The photovoltaic device includes: at least one photovoltaic module 1, at least one inverter 2, and any one of the fast shutdown devices 3 in the above embodiments. The photovoltaic device of this application has the corresponding functional modules and beneficial effects of the fast shutdown device 3 provided in the above embodiments, and the same parts will not be described again.

[0050] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0051] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A fast shutdown device applied to a photovoltaic device, the photovoltaic device comprising at least one photovoltaic module and at least one inverter, the fast shutdown device being electrically connected between the photovoltaic module and the inverter, characterized in that: The fast shutdown device includes: a first control unit, and at least one switching circuit and at least one detection unit that communicate with the first control unit respectively; The switching circuit is used to connect and disconnect the electrical connection between the photovoltaic module and the inverter. The detection unit collects pulsating current signals at one end of the switching circuit that is electrically connected to the inverter. The first control unit receives the pulsating current signal from the detection unit and sends a switching control signal to the switching circuit. The switching circuit includes: a DC-DC buck converter circuit; The DC-DC buck converter circuit includes: a main switching device, a freewheeling device, a filtering device, and an energy storage device; One current terminal of the main switching device is electrically connected to the positive terminal of the photovoltaic module, and the other current terminal is electrically connected to one end of the filter device; the control terminal of the main switching device communicates with the first control unit. One current terminal of the freewheeling device is electrically connected to the negative terminal of the photovoltaic module, and the other current terminal is electrically connected to one end of the filter device that is electrically connected to the main switching device. One current terminal of the energy storage device is electrically connected to the negative terminal of the photovoltaic module, and the other current terminal is electrically connected to one end of the filter device that is electrically connected to the inverter.

2. The rapid shutdown device according to claim 1, characterized in that, The detection unit includes any one of the following: a current transformer, a detection resistor, a shunt, a Hall sensor, and an inductor coil.

3. The fast shutdown device according to claim 1, characterized in that, The main switching device is a through-type switching transistor or a pulse-driven switching transistor.

4. The fast shutdown device according to claim 1, characterized in that, The freewheeling device is a freewheeling diode.

5. The rapid shutdown device according to claim 1, characterized in that, The freewheeling device includes any one of the following: MOSFET, IGBT, or thyristor.

6. The rapid shutdown device according to claim 5, characterized in that, The freewheeling device includes a control terminal, which communicates with the first control unit.

7. The rapid shutdown device according to claim 1, characterized in that, The fast shutdown device further includes: a second control unit, which may be set independently or integrated with the inverter; the second control unit receives voltage or current signals from the first control unit.

8. The fast shutdown device according to claim 1, characterized in that, The rapid shutdown device further includes a communication unit, which communicates with the first control unit and the terminal device respectively. The communication unit receives instruction information from the terminal device and sends the received instruction information to the first control unit.

9. A photovoltaic device, characterized in that, include: At least one photovoltaic module, at least one inverter, and the fast shutdown device according to any one of claims 1-8.

Images