Switch circuits, switch circuits, and photovoltaic shutdown systems for photovoltaic modules

Abstract

This utility model proposes a switch-off circuit, a switch-off device, and a photovoltaic switch-off system for photovoltaic modules, belonging to the field of circuit switch-off technology. The switch-off circuit for photovoltaic modules includes a power-taking module, a control module, a switch-off module, a positive input terminal H1, a negative input terminal H2, a positive output terminal H3, and a negative output terminal H4. The power-taking module includes a first-stage step-down unit and a second-stage step-down unit. The first-stage step-down unit steps down the source voltage provided by the photovoltaic module to power the switch-off module. The first-stage step-down unit steps down the high-voltage DC power (e.g., 300V) provided by the photovoltaic module to an intermediate voltage (e.g., 12V) to power the switch-off module. The second-stage step-down unit further stabilizes the intermediate voltage to the operating voltage required by the control module (e.g., 3.3V), realizing voltage matching between the photovoltaic power supply system and low-voltage electrical equipment, and effectively reducing the overall size of the switch-off device.

Description

Technical Field

[0001] This utility model belongs to the field of circuit shutdown technology, and relates to the shutdown technology of photovoltaic modules, specifically a shutdown circuit, a shutdown device, and a photovoltaic shutdown system for photovoltaic modules. Background Technology

[0002] A photovoltaic (PV) shutdown device is a switching device used for the safety protection of PV systems. Its core function is to quickly disconnect the circuit between the PV modules and the inverter, thereby eliminating high-voltage risks. According to the requirements of the U.S. National Electrical Code (NEC 2023), PV shutdown devices must reduce the voltage of the PV module array to a safe level (typically below 30V or 80V) within 30 seconds to ensure personal safety.

[0003] Most current circuit breakers are designed to meet the requirements of the U.S. National Electrical Code (NEC2023) and control the circuit connection between photovoltaic modules and inverters. Most circuit breakers include a control module and a shutdown module. When the control module detects an abnormal situation, it controls the shutdown module to disconnect, thereby cutting off the current path between the photovoltaic modules and inverters.

[0004] However, the shutdown device requires separate power supplies for both the control module and the shutdown module during operation, resulting in a very large device size. To reduce the size of the shutdown device, some existing technologies have proposed directly drawing power from the photovoltaic modules to supply the control and shutdown modules. However, in practical applications, the voltage provided by the photovoltaic modules is at least 100 volts, especially thin-film photovoltaics which can provide up to 300 volts, while the control and shutdown modules require only a few volts to a dozen volts. This leads to a voltage mismatch between the power supply equipment (photovoltaic modules) and the power consumption equipment (control and shutdown modules). Utility Model Content

[0005] In view of the above-described background technology, existing photovoltaic modules provide high voltage, while the control module and shutdown module require low voltage, resulting in a voltage mismatch between the power supply equipment (photovoltaic module) and the power consumption equipment (control module and shutdown module). To address this technical problem, this utility model proposes a shutdown circuit, a shutdown device, and a photovoltaic shutdown system for photovoltaic modules.

[0006] This utility model is equipped with a power extraction module, which includes a primary step-down unit and a secondary step-down unit. The primary step-down unit steps down the high-voltage DC power (e.g., 300V) provided by the photovoltaic module to an intermediate voltage (e.g., 12V) to power the shutdown module. The secondary step-down unit further stabilizes the intermediate voltage to the operating voltage required by the control module (e.g., 3.3V), realizing voltage matching between the photovoltaic power supply system and low-voltage electrical equipment, and effectively reducing the overall size of the shutdown device.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A switch circuit for photovoltaic modules includes a power-harvesting module, a control module, a switch-off module, a positive input terminal H1, a negative input terminal H2, a positive output terminal H3, and a negative output terminal H4. The power-harvesting module includes a first-stage step-down unit and a second-stage step-down unit.

[0009] The input terminal of the first-stage step-down unit is connected between the positive input terminal H1 and the positive output terminal H3. The output terminal of the first-stage step-down unit is connected to the input terminal of the second-stage step-down unit. The output terminal of the first-stage step-down unit is also connected to the shutdown module.

[0010] The output terminal of the secondary step-down unit is connected between the negative input terminal H2 and the negative output terminal H4. The output terminal of the secondary step-down unit is also connected to the control module.

[0011] The shutdown module is connected between the positive input terminal H1 and the positive output terminal H3 or between the negative input terminal H2 and the negative output terminal H4.

[0012] The control module communicates with the shutdown module to control the shutdown module's actions.

[0013] Furthermore, the switch circuit for photovoltaic modules also includes a detection module, and the output of the secondary step-down unit is connected to the detection module; the detection module communicates with the control module.

[0014] Further specifying, the detection module includes a current detection unit, a temperature detection unit, and a voltage detection unit, wherein the current detection unit and the temperature detection unit are both connected to the output terminal of the two-stage step-down unit; and the current detection unit, the temperature detection unit, and the voltage detection unit all communicate with the control module.

[0015] Further defined, the shutdown module includes a first switch, a second switch, and a third switch connected sequentially from front to back, wherein the third switch is connected to both the negative input terminal H2 and the negative output terminal H4;

[0016] The output terminal of the first-stage step-down unit is connected to the first switch, the second switch, and / or the third switch; the control module communicates with the first switch.

[0017] Furthermore, the switch circuit for the photovoltaic module also includes a bypass diode, wherein one end of the bypass diode is connected between the positive input terminal H1 and the positive output terminal H3, and the other end of the bypass diode is connected between the negative input terminal H2 and the negative output terminal H4.

[0018] Furthermore, the switch circuit for photovoltaic modules also includes a radio frequency module, which is connected to the control module.

[0019] A switch for a photovoltaic module includes a positive input wire, a positive output wire, a negative input wire, a negative output wire, and the aforementioned switch for the photovoltaic module. The positive input wire is connected to a positive input terminal H1, the positive output wire is connected to a positive output terminal H3, the negative input wire is connected to a negative input terminal H2, and the negative output wire is connected to a negative output terminal H4.

[0020] A photovoltaic shutdown system includes a photovoltaic module, a connector, and the aforementioned shutdown device for the photovoltaic module, wherein the positive input wire and the negative input wire are both connected to the photovoltaic module, and the positive output wire and the negative output wire are both connected to the connector.

[0021] There are multiple photovoltaic modules, connectors, and turn-off devices for photovoltaic modules, and the number of each is the same. Each photovoltaic module, its corresponding connector, and its turn-off device for photovoltaic modules form a turn-off subsystem.

[0022] Furthermore, the photovoltaic shutdown system also includes an inverter and a load connected to the output terminal of the inverter; multiple sets of the shutdown subsystems are connected in series to the input terminal of the inverter.

[0023] Further specifying, each of the aforementioned shutdown subsystems is provided with two connectors, one of which is connected to both the positive and negative input terminals and is also connected to the photovoltaic module; the other connector is connected to both the positive and negative output terminals.

[0024] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0025] 1. The circuit system of the switch of this utility model is provided with a power supply module, which includes a first-stage step-down unit and a second-stage step-down unit. The first-stage step-down unit steps down the high-voltage DC power (e.g., 300V) provided by the photovoltaic module to an intermediate voltage (e.g., 12V) to power the switch-down module. The second-stage step-down unit further stabilizes the intermediate voltage to the operating voltage required by the control module (e.g., 3.3V), realizing voltage matching between the photovoltaic power supply system and low-voltage electrical equipment, and effectively reducing the overall size of the switch.

[0026] 2. The shutdown circuit system of this utility model further includes a detection module, which consists of a current detection unit, a temperature detection unit, and a voltage detection unit, used for real-time monitoring of the operating status of the photovoltaic module. The control module receives and judges whether the parameter values ​​collected by the current detection unit, temperature detection unit, and voltage detection unit exceed a preset safety threshold; when any parameter value is abnormal, the control module immediately drives the shutdown module to cut off the circuit path between the photovoltaic module and the inverter, thereby realizing fault self-checking and safety linkage control, effectively ensuring personal and equipment safety.

[0027] 3. The shutdown module in this utility model adopts a three-stage switch structure, which is composed of a first switch, a second switch and a third switch connected in series. It can provide multi-stage isolation and redundant cut-off paths in high-voltage circuits, and improve the reliability and cut-off capability of the shutdown action between photovoltaic modules and inverters through multi-stage shutdown.

[0028] 4. This utility model introduces a bypass diode in the shutdown circuit. After the shutdown module cuts off the circuit between the photovoltaic module and the inverter (at this time, the voltage difference between the positive output terminal H3 and the negative output terminal H4 approaches zero), the bypass diode can establish an alternative conduction path in a short time, avoiding voltage backflow or thermal damage caused by the photovoltaic module stopping power generation, while ensuring the normal operation of other modules in the series photovoltaic module. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a switch circuit for photovoltaic modules according to the present invention. Figure 1 ;

[0030] Figure 2 This is a schematic diagram of a switch circuit for photovoltaic modules according to the present invention. Figure 2 ;

[0031] Figure 3 This is a schematic diagram of a circuit breaker;

[0032] Figure 4 Schematic diagram of a photovoltaic shutdown system Figure 1 ;

[0033] Figure 5 Schematic diagram of a photovoltaic shutdown system Figure 2 ;

[0034] Figure 6 Schematic diagram of a photovoltaic shutdown system Figure 3 . Detailed Implementation

[0035] The technical solution of this utility model will be further explained and described below with reference to the accompanying drawings and embodiments, but this utility model is not limited to the embodiments described below.

[0036] The technical concept of directly drawing power from the photovoltaic module to supply power to the control and shutdown modules in this invention is primarily aimed at thin-film photovoltaics (photovoltaic modules or photovoltaic components), but it is also applicable to other conventional photovoltaic systems. The technical solution of this invention will be specifically described below using thin-film photovoltaics as an example.

[0037] See Figure 1 and Figure 2 This utility model relates to a switch-off circuit for photovoltaic modules, comprising a power-harvesting module, a control module, a switch-off module, a positive input terminal H1, a negative input terminal H2, a positive output terminal H3, and a negative output terminal H4. The power-harvesting module includes a first-stage step-down unit and a second-stage step-down unit. The input terminal of the first-stage step-down unit is connected between the positive input terminal H1 and the positive output terminal H3, and the output terminal of the first-stage step-down unit is connected to the input terminal of the second-stage step-down unit. The output terminal of the first-stage step-down unit is also connected to the switch-off module. The output terminal of the second-stage step-down unit is connected to the control module. The switch-off module is connected between the positive input terminal H1 and the positive output terminal H3 or between the negative input terminal H2 and the negative output terminal H4. The control module is electrically connected to the switch-off module and is used to control the operating state of the switch-off module.

[0038] In this invention, preferably, the output voltage of the thin-film photovoltaic is 300V. Figure 2 In the process, the 300V voltage is reduced to 12V through the first-stage step-down unit to power the shutdown module; at the same time, the 12V voltage is reduced to 3.3V through the second-stage step-down unit to power the control module, so that the voltage taken by the power-taking module matches the voltage between the power-consuming equipment (control module and shutdown module), reducing the size of the shutdown device.

[0039] The primary and secondary step-down units and the control module of this invention are all commercially available products. The primary and secondary step-down units can be linear regulators, switching regulators, or other step-down modules well-known to those skilled in the art. Preferably, the primary and secondary step-down units in this invention are switching regulators of model VIPER06XS; the control module is an STM32WLE5CC chip. The shutdown module can be a conventional switch or MOSFET structure.

[0040] This utility model's switch-off circuit for photovoltaic modules also includes a detection module, and the output terminal of the secondary step-down unit is connected to the detection module; the detection module communicates with the control module. Specifically, the detection module includes a current detection unit, a temperature detection unit, and a voltage detection unit, with the current detection unit and temperature detection unit connected to the output terminal of the secondary step-down unit; the current detection unit, temperature detection unit, and voltage detection unit all communicate with the control module. Preferably, in... Figure 2In the middle, both the current detection unit and the temperature detection unit are connected to the two-stage step-down unit, which supplies power to the current detection unit and the temperature detection unit.

[0041] In this invention, the current value of the current detection unit, the temperature value of the temperature detection unit, and the voltage value detected by the voltage detection unit are all transmitted to the control module. The control module compares the current value, temperature value, and voltage value detected by the current detection unit, temperature detection unit, and voltage detection unit with the set standard current value, standard temperature value, and standard voltage value, respectively. When any of the current value, temperature value, and voltage value is abnormal, it is determined that an abnormal situation has occurred. The control module controls the shutdown module to cut off the current path of the photovoltaic module to which it belongs, eliminate the risk of high voltage output, and ensure personal safety.

[0042] Preferably, in this invention, the shutdown module includes a first switch, a second switch, and a third switch connected sequentially from front to back. The first switch is connected to the control module, with one end connected to the negative input terminal H2 and the other end connected to the negative output terminal H4. The output terminal of the first-stage step-down unit is connected to the second switch. The control module outputs a voltage level to the first switch, the first switch outputs a voltage level to the second switch, and the second switch outputs a voltage level to the third switch. The first, second, and third switches can be configured as transistors or MOSFETs, and using multiple switches can improve the shutdown effect of a single photovoltaic module.

[0043] The present invention provides a switch circuit for photovoltaic modules that also includes a bypass diode. One end of the bypass diode is connected between the positive input terminal H1 and the positive output terminal H3, and the other end is connected between the negative input terminal H2 and the negative output terminal H4. The bypass diode is used to conduct between the positive output terminal H3 and the negative output terminal H4 when the photovoltaic module is completely shaded or damaged and does not generate electricity (at which time the voltage difference between the positive output terminal H3 and the negative output terminal H4 is almost 0). This prevents the photovoltaic module that does not generate electricity from affecting the conduction of its photovoltaic module string, which could cause voltage backflow or thermal damage. At the same time, it ensures the normal operation of other modules in the series-connected photovoltaic modules.

[0044] Preferably, the switch circuit for photovoltaic modules of this utility model further includes a radio frequency (RF) module, which is connected to the control module. Specifically, the control module supplies power to the RF module, and the RF module is used to transmit the current value, temperature value, voltage value, and abnormal conditions in the control module to the host computer or other terminal devices wirelessly.

[0045] See Figure 3This utility model discloses a switch for photovoltaic modules, comprising a positive input wire, a positive output wire, a negative input wire, a negative output wire, and the aforementioned switch for photovoltaic modules. The positive input wire is connected to the positive input terminal H1, the positive output wire is connected to the positive output terminal H3, the negative input wire is connected to the negative input terminal H2, and the negative output wire is connected to the negative output terminal H4. The positive input and positive output wires are used to connect to the photovoltaic module (photovoltaic assembly), and the negative input and negative output wires are used to connect to an inverter or load.

[0046] See Figure 4 As one implementation of this embodiment: a photovoltaic shutdown system includes a photovoltaic module, a connector, and the aforementioned shutdown device for the photovoltaic module. The positive input wire and the negative input wire are both connected to the photovoltaic module, and the positive output wire and the negative output wire are both connected to the connector. There are multiple photovoltaic modules, connectors, and shutdown devices for the photovoltaic module, and the number is the same. Each photovoltaic module, its corresponding connector, and its shutdown device for the photovoltaic module form a shutdown subsystem.

[0047] See Figure 5 As one implementation of this embodiment: a photovoltaic shutdown system includes a photovoltaic module, two connectors, and the aforementioned shutdown device for the photovoltaic module. One connector is connected to both the positive and negative input terminals and is also connected to the photovoltaic module. The other connector is connected to both the positive and negative output terminals. There are multiple photovoltaic modules, two connectors, and multiple shutdown devices for the photovoltaic module, and each photovoltaic module, along with its corresponding two connectors and one shutdown device for the photovoltaic module, forms a shutdown subsystem.

[0048] See Figure 6 The present invention provides a photovoltaic shutdown system, which also includes an inverter and a load connected to the output terminal of the inverter; multiple shutdown subsystems are connected in series and then connected to the input terminal of the inverter.

[0049] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A switch circuit for photovoltaic modules, characterized in that, It includes a power supply module, a control module, a shutdown module, a positive input terminal H1, a negative input terminal H2, a positive output terminal H3, and a negative output terminal H4. The power supply module includes a first-stage step-down unit and a second-stage step-down unit. The input terminal of the first-stage step-down unit is connected between the positive input terminal H1 and the positive output terminal H3. The output terminal of the first-stage step-down unit is connected to the input terminal of the second-stage step-down unit. The output terminal of the first-stage step-down unit is also connected to the shutdown module. The output terminal of the secondary step-down unit is connected between the negative input terminal H2 and the negative output terminal H4. The output terminal of the secondary step-down unit is also connected to the control module. The shutdown module is connected between the positive input terminal H1 and the positive output terminal H3 or between the negative input terminal H2 and the negative output terminal H4. The control module communicates with the shutdown module to control the shutdown module's actions.

2. The switch circuit for photovoltaic modules according to claim 1, characterized in that, The switch circuit for photovoltaic modules also includes a detection module, and the output of the secondary step-down unit is connected to the detection module; the detection module communicates with the control module.

3. The switch circuit for photovoltaic modules according to claim 2, characterized in that, The detection module includes a current detection unit, a temperature detection unit, and a voltage detection unit. The current detection unit and the temperature detection unit are both connected to the output terminal of the two-stage step-down unit. The current detection unit, the temperature detection unit, and the voltage detection unit all communicate with the control module.

4. The switch circuit for photovoltaic modules according to claim 1, characterized in that, The shutdown module includes a first switch, a second switch, and a third switch connected in sequence from front to back, wherein the third switch is connected to both the negative input terminal H2 and the negative output terminal H4. The output terminal of the first-stage step-down unit is connected to the first switch, the second switch, and / or the third switch; the control module communicates with the first switch.

5. The switch circuit for photovoltaic modules according to claim 1, characterized in that, The switch circuit for photovoltaic modules also includes a bypass diode, wherein one end of the bypass diode is connected between the positive input terminal H1 and the positive output terminal H3, and the other end of the bypass diode is connected between the negative input terminal H2 and the negative output terminal H4.

6. The switch circuit for photovoltaic modules according to claim 1, characterized in that, The switch circuit for photovoltaic modules also includes a radio frequency module, which is connected to the control module.

7. A switch for photovoltaic modules, characterized in that, The device includes a positive input wire, a positive output wire, a negative input wire, a negative output wire, and a switch for a photovoltaic module as described in any one of claims 1-6. The positive input wire is connected to the positive input terminal H1, the positive output wire is connected to the positive output terminal H3, the negative input wire is connected to the negative input terminal H2, and the negative output wire is connected to the negative output terminal H4.

8. A photovoltaic shutdown system, characterized in that, It includes a photovoltaic module, a connector, and a switch for a photovoltaic module as described in claim 7, wherein the positive input wire and the negative input wire are both connected to the photovoltaic module, and the positive output wire and the negative output wire are both connected to the connector. There are multiple photovoltaic modules, connectors, and turn-off devices for photovoltaic modules, and the number of each is the same. Each photovoltaic module, its corresponding connector, and its turn-off device for photovoltaic modules form a turn-off subsystem.

9. The photovoltaic shutdown system according to claim 8, characterized in that, The photovoltaic shutdown system also includes an inverter and a load connected to the output of the inverter; multiple sets of the shutdown subsystems are connected in series to the input of the inverter.

10. The photovoltaic shutdown system according to claim 8, characterized in that, Each of the aforementioned shutdown subsystems is equipped with two connectors. One connector is connected to both the positive and negative input terminals and is also connected to the photovoltaic module. The other connector is connected to both the positive and negative output terminals.

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