Photovoltaic junction box

Abstract

The utility model discloses a photovoltaic junction box which comprises a first junction box, a second junction box and a third junction box which are arranged in sequence. A first MOS transistor, a second MOS transistor, a switch unit, a control unit and a connecting wire are arranged in the second junction box, one end of the connecting wire is electrically connected with the anode input of the second junction box, the other end of the connecting wire is electrically connected with the anode output of the second junction box, the first end of the first MOS transistor is electrically connected with the cathode input of the second junction box, and the second end of the second MOS transistor is electrically connected with the anode output of the second junction box. The second end of the first MOS tube is electrically connected with the first end of the switch unit, the third end of the first MOS tube is electrically connected with the negative output end of the second junction box, the second end of the switch unit is electrically connected with the first end of the second MOS tube, and the second end of the second MOS tube is electrically connected with the connecting wire. The third end of the second MOS tube is electrically connected with the negative electrode output of the second junction box, and the control unit is electrically connected with the third end of the switch unit.

Description

Technical Field

[0001] The utility model belongs to the technical field of photovoltaic accessories, and particularly relates to a photovoltaic junction box. Background Art

[0002] Due to the renewable and clean nature of solar energy, photovoltaic grid-connected power generation technology has experienced rapid development. Currently, photovoltaic systems consist of multiple photovoltaic modules connected in series to form a photovoltaic string, which is then converted into AC power by an inverter and transmitted to the grid. Conventional photovoltaic module junction boxes are a key component of photovoltaic modules. Their primary function is to weld the positive and negative conductors within the module and to install and secure the bypass diodes. The bypass diodes conduct when the module is obscured, thus preventing the hot spot effect. The positive and negative lead wires within the module are connected to metal sheets within the junction box, which are provided with positive and negative welding areas, respectively. These areas are separated by bypass diodes. Under normal circumstances, the positive and negative metal sheets within the junction box are not conductive. Only when the bypass diodes are conductive do the positive and negative metal sheets directly conduct, bypassing the two battery strings on either side of the bypass diodes.

[0003] The structure of a photovoltaic junction box is generally determined by the internal circuitry of the photovoltaic module. Conventional half-cell photovoltaic modules consist of six strings of cells connected end to end, typically equipped with a three-part junction box. This refers to a structure consisting of a negative junction box, an intermediate junction box, and a positive junction box. The three boxes are connected in series via internal electrical components (such as copper sheets and diodes). In practice, a junction box is installed between the first and second strings, another between the third and fourth strings, and another between the fifth and sixth strings. Each junction box typically contains a bypass diode, with the positive and negative terminals welded to two metal sheets, respectively, to which the positive and negative leads from the photovoltaic module are welded. However, the junction box of the photovoltaic module requires the external installation of a module disconnect and a module disconnect controller to shut down the photovoltaic module. The installation of these disconnects can increase the complexity of on-site construction. Utility Model Content

[0004] The purpose of the utility model is to provide a photovoltaic junction box, which can realize the shutdown of the entire photovoltaic module by simply changing the closing and opening conditions of the first MOS tube and the second MOS tube inside the second junction box. When the photovoltaic module is blocked, the second MOS tube plays a bypass protection function, thereby reducing the construction difficulty at the construction site.

[0005] The utility model adopts a technical solution to solve its technical problem, which is to provide a photovoltaic junction box, including a first junction box, a second junction box and a third junction box arranged in sequence; the first junction box and the third junction box are provided with bypass protection diodes, the second junction box is provided with a first MOS transistor, a second MOS transistor, a switch unit, a control unit and a connecting wire, one end of the connecting wire is electrically connected to the positive input of the second junction box, and the other end is electrically connected to the positive output of the second junction box, the first end of the first MOS transistor is electrically connected to the negative input of the second junction box, the second end of the first MOS transistor is electrically connected to the first end of the switch unit, the third end of the first MOS transistor is electrically connected to the negative output of the second junction box, the second end of the switch unit is electrically connected to the first end of the second MOS transistor, the second end of the second MOS transistor is electrically connected to the connecting wire, the third end of the second MOS transistor is electrically connected to the negative output of the second junction box, and the control unit is electrically connected to the third end of the switch unit.

[0006] In an embodiment of the present application, a capacitor is further provided in the second junction box, one end of the capacitor is electrically connected to the negative input of the second junction box, and the other end is electrically connected to the positive input of the second junction box.

[0007] In an embodiment of the present application, an inductor is further provided in the second junction box, a first end of the inductor is electrically connected to the third end of the first MOS transistor and the third end of the second MOS transistor, and a second end of the inductor is electrically connected to the negative output of the second junction box.

[0008] In an embodiment of the present application, a voltage sampling unit is further provided in the second junction box, wherein a first end of the voltage sampling unit is electrically connected to the negative input of the second junction box, a second end is electrically connected to the positive input of the second junction box, and a third end is electrically connected to the control unit.

[0009] In an embodiment of the present application, the voltage sampling unit includes a voltage divider resistor and an acquisition chip, an ADC acquisition module is provided on the acquisition chip, the acquisition chip is electrically connected to the voltage divider resistor, one end of the voltage divider resistor is electrically connected to the negative input of the second junction box, and the other end is electrically connected to the positive input of the second junction box.

[0010] In the embodiment of the present application, an energy storage unit is further provided in the second junction box, and the energy storage unit is electrically connected to the control unit.

[0011] In the embodiment of the present application, the energy storage unit is a battery or a capacitor.

[0012] In the embodiment of the present application, a communication unit is further provided in the second junction box, and the communication unit is electrically connected to the control unit.

[0013] In an embodiment of the present application, the communication unit includes a coupling circuit.

[0014] In the embodiment of the present application, the switching unit is a transistor.

[0015] The beneficial effects of the utility model are:

[0016] 1. The utility model provides a photovoltaic junction box. When the photovoltaic module is unobstructed, if the second MOS transistor is disconnected and the first MOS transistor is closed, a conductive path is formed between the positive input and negative input of the entire second junction box, and a conductive path is formed between the positive output and negative output. Therefore, the electrical energy on the photovoltaic module is converted into AC power by the inverter and then transmitted to the power grid. If the second MOS transistor is disconnected and the first MOS transistor is disconnected, the conductive path formed between the positive input and negative input of the second junction box is cut off, thereby shutting down the entire photovoltaic module. When the photovoltaic module is blocked, the second MOS transistor is closed and the first MOS transistor is disconnected. At this time, the second MOS transistor is bypassed, thereby avoiding the hot spot effect. The entire photovoltaic module can be shut down by simply changing the closed and open conditions of the first and second MOS transistors inside the second junction box. When the photovoltaic module is blocked, the second MOS transistor serves as a bypass protection function, thereby reducing the construction difficulty at the construction site.

[0017] 2. In the photovoltaic junction box proposed by the present invention, a capacitor is further provided in the second junction box to reduce the impact of current changes on the entire circuit in the second junction box and reduce noise interference;

[0018] 3. In the photovoltaic junction box proposed by the present invention, an inductor is further provided in the second junction box. The inductor ensures that the current flowing through the inductor does not undergo sudden changes, thereby ensuring the stability of the power supply in the entire photovoltaic junction box. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated into and constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present invention, but not all. Those skilled in the art can derive other drawings from these drawings without inventive effort.

[0020] Figure 1 This is a diagram showing the internal structure of a second junction box of a photovoltaic junction box according to an embodiment of the present utility model;

[0021] Figure 2 The figure is a schematic diagram of the installation of a photovoltaic junction box according to an embodiment of the present utility model.

[0022] In the figure: 100, first junction box; 200, second junction box; 201, first MOS transistor; 202, second MOS transistor; 203, switch unit; 204, control unit; 205, connecting wire; 206, capacitor; 207, inductor; 208, voltage sampling unit; 209, energy storage unit; 210, communication unit; 300, third junction box; 400, photovoltaic module. DETAILED DESCRIPTION

[0023] To more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the following describes specific embodiments of the present invention with reference to the accompanying drawings. Obviously, the drawings described below are merely examples of the present invention. A person skilled in the art can, without inventive effort, derive other drawings and other embodiments from these drawings. Furthermore, design orientations only represent relative positional relationships between components, not absolute positional relationships.

[0024] The present invention provides a photovoltaic junction box. Figure 1 、 Figure 2 , mainly includes a first junction box 100, a second junction box 200 and a third junction box 300.

[0025] In an embodiment of the present application, the photovoltaic junction box includes a first junction box 100, a second junction box 200, and a third junction box 300 arranged in sequence, wherein the first junction box 100 and the third junction box 300 are provided with bypass protection diodes, and the second junction box 200 is provided with a first MOS tube 201, a second MOS tube 202, a switch unit 203, a control unit 204, and a connecting wire 205. One end of the connecting wire 205 is electrically connected to the positive input of the second junction box 200, and the other end is electrically connected to the positive output of the second junction box 200. The first end of the first MOS transistor 201 is electrically connected to the negative input of the second junction box 200, the second end of the first MOS transistor 201 is electrically connected to the first end of the switch unit 203, the third end of the first MOS transistor 201 is electrically connected to the negative output of the second junction box 200, the second end of the switch unit 203 is electrically connected to the first end of the second MOS transistor 202, the second end of the second MOS transistor 202 is electrically connected to the connecting wire 205, the third end of the second MOS transistor 202 is electrically connected to the negative output of the second junction box 200, and the control unit 204 is electrically connected to the switch unit 203. The control unit 204 sends an electrical signal to the switch unit 203. After receiving the electrical signal sent by the control unit 204, the switch unit 203 sends electrical signals to the first MOS transistor 201 and the second MOS transistor 202 respectively. The first MOS transistor 201 and the second MOS transistor 202 switch between closed and open according to the electrical signal sent by the switch unit 203. When the photovoltaic module is not blocked, if the second MOS transistor 202 is disconnected, the first MOS transistor 201 is closed. At this time, a positive input and a negative input of the entire second junction box 200 are formed. A conduction path is formed between the positive output and the negative output, thereby converting the electrical energy on the photovoltaic module into AC power through the inverter and transmitting it to the power grid. If the second MOS tube 202 is disconnected and the first MOS tube 201 is disconnected, the conduction path formed between the positive input and the negative input of the second junction box 200 is cut off, thereby realizing the shutdown of the entire photovoltaic module; when the photovoltaic module is blocked, the second MOS tube 202 is closed and the first MOS tube 201 is disconnected. At this time, the second MOS tube 202 is bypassed, thereby avoiding the hot spot effect. Compared with the prior art, the junction box of the photovoltaic module needs to install a component shutoff device and a component shutoff controller on the outside to realize the shutdown of the photovoltaic module. In this application, the entire photovoltaic module can be shut down by only changing the closing and disconnection conditions of the first MOS tube 201 and the second MOS tube 202 inside the second junction box 200, and when the photovoltaic module is blocked, the second MOS tube 202 plays the function of bypass protection, thereby reducing the construction difficulty at the construction site.

[0026] It should be noted that the positive input, negative input, positive output and negative output of the second junction box 200 may specifically be metal sheets fixed inside the second junction box 200 .

[0027] In one embodiment, a capacitor 206 is further disposed within second junction box 200. One end of capacitor 206 is electrically connected to the negative input of second junction box 200, and the other end is electrically connected to the positive input of second junction box 200. Capacitor 206 is used to reduce the impact of current changes on the entire circuit within second junction box 200 and to reduce noise interference.

[0028] In one embodiment, an inductor 207 is further provided in the second junction box 200. The first end of the inductor 207 is electrically connected to the third end of the first MOS tube 201 and the third end of the second MOS tube 202, and the second end of the inductor 207 is electrically connected to the negative output of the second junction box 200. The inductor 207 ensures that the current flowing through the inductor 207 does not change suddenly, thereby ensuring the stability of the power supply in the entire photovoltaic junction box.

[0029] In one embodiment, a voltage sampling unit 208 is further provided in the second junction box 200 , wherein a first end of the voltage sampling unit 208 is electrically connected to the negative input of the second junction box 200 , a second end is electrically connected to the positive input of the second junction box 200 , and a third end is electrically connected to the control unit 204 .

[0030] Furthermore, the voltage sampling unit 208 includes a voltage divider resistor and an acquisition chip. The acquisition chip is provided with an ADC acquisition module. The acquisition chip is electrically connected to the voltage divider resistor. One end of the voltage divider resistor is electrically connected to the negative input of the second junction box 200, and the other end is electrically connected to the positive input of the second junction box 200.

[0031] In one embodiment, the second junction box 200 is further provided with an energy storage unit 209, which is electrically connected to the control unit 204. The energy storage unit 209 stores electrical energy and provides a small amount of electrical energy when the junction box cannot maintain normal circuit operation, thereby avoiding sudden power outages.

[0032] Specifically, the energy storage unit 209 may be a battery or a capacitor.

[0033] In one embodiment, a communication unit 210 is further provided in the second junction box 200 , and the communication unit 210 is electrically connected to the control unit 204 .

[0034] Furthermore, the communication unit 210 includes a coupling circuit, and the coupling circuit is decoupled to obtain a shutdown instruction of the second junction box 200 .

[0035] As an example, the coupling circuit may be a photoelectric coupler or implemented through other coupling methods.

[0036] In one implementation, the switch unit 203 may be a transistor, a diode, and a PWM signal amplifier, or a combination of these.

[0037] In one embodiment, the control unit 204 may be a central processing unit (CPU), a graphics processing unit (GPU), a modem, or a combination thereof.

[0038] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0039] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific embodiments of the present invention are not limited to these descriptions. For those skilled in the art of the present invention, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A photovoltaic junction box, characterized in that: The invention comprises a first junction box (100), a second junction box (200) and a third junction box (300) arranged in sequence; the first junction box (100) and the third junction box (300) are provided with bypass protection diodes; the second junction box (200) is provided with a first MOS tube (201), a second MOS tube (202), a switch unit (203), a control unit (204) and a connecting wire (205); one end of the connecting wire (205) is electrically connected to the positive input of the second junction box (200), and the other end is electrically connected to the positive output of the second junction box (200); the first end of the first MOS tube (201) is electrically connected to the positive input of the second junction box (200), and the other end is electrically connected to the positive output of the second junction box (200); the first end of the first MOS tube (201) is electrically connected to the positive input of the second junction box (200), and the second end of the first MOS tube (201) is electrically connected to the positive output of the second junction box (200). The second junction box (200) is electrically connected to the negative input, the second end of the first MOS transistor (201) is electrically connected to the first end of the switch unit (203), the third end of the first MOS transistor (201) is electrically connected to the negative output of the second junction box (200), the second end of the switch unit (203) is electrically connected to the first end of the second MOS transistor (202), the second end of the second MOS transistor (202) is electrically connected to the connecting wire (205), the third end of the second MOS transistor (202) is electrically connected to the negative output of the second junction box (200), and the control unit (204) is electrically connected to the third end of the switch unit (203).

2. A photovoltaic junction box according to claim 1, characterized in that: A capacitor (206) is further provided in the second junction box (200), one end of the capacitor (206) being electrically connected to the negative input of the second junction box (200), and the other end being electrically connected to the positive input of the second junction box (200).

3. The photovoltaic junction box according to claim 1, characterized in that: An inductor (207) is further provided in the second junction box (200), a first end of the inductor (207) being electrically connected to the third end of the first MOS tube (201) and the third end of the second MOS tube (202), and a second end of the inductor (207) being electrically connected to the negative output of the second junction box (200).

4. The photovoltaic junction box according to claim 1, characterized in that: A voltage sampling unit (208) is further provided in the second junction box (200), wherein a first end of the voltage sampling unit (208) is electrically connected to the negative input of the second junction box (200), a second end is electrically connected to the positive input of the second junction box (200), and a third end is electrically connected to the control unit (204).

5. The photovoltaic junction box according to claim 4, characterized in that: The voltage sampling unit (208) comprises a voltage dividing resistor and an acquisition chip, wherein an ADC acquisition module is provided on the acquisition chip, the acquisition chip is electrically connected to the voltage dividing resistor, one end of the voltage dividing resistor is electrically connected to the negative input of the second junction box (200), and the other end is electrically connected to the positive input of the second junction box (200).

6. The photovoltaic junction box according to claim 1, characterized in that: An energy storage unit (209) is also provided in the second junction box (200), and the energy storage unit (209) is electrically connected to the control unit (204).

7. The photovoltaic junction box according to claim 6, characterized in that: The energy storage unit (209) is a battery or a capacitor.

8. The photovoltaic junction box according to claim 1, characterized in that: A communication unit (210) is further provided in the second junction box (200), and the communication unit (210) is electrically connected to the control unit (204).

9. The photovoltaic junction box according to claim 8, characterized in that: The communication unit (210) includes a coupling circuit.

10. The photovoltaic junction box according to claim 9, characterized in that: The switch unit (203) is a triode.

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