Photovoltaic inverter and temperature sensing device

Abstract

Photovoltaic inverter, wherein the photovoltaic inverter comprises: a plurality of photovoltaic terminals, a converter, a printed circuit board, a temperature sensing circuit and a housing structure; wherein the converter and the printed circuit board are arranged within the housing structure; wherein the photovoltaic terminals each penetrate the housing structure and have one end inside the housing structure that is electrically connected to the printed circuit board and another end outside the housing structure that is configured to be connected to a photovoltaic module;wherein the printed circuit board comprises an electrically conductive layer and a thermally conductive insulating layer, wherein the electrically conductive layer is configured to transfer electrical energy generated by the plurality of photovoltaic modules to the converter, and the thermally conductive insulating layer is configured to conduct heat generated by the photovoltaic connection to the temperature sensing circuit; wherein the temperature sensing circuit is configured to detect a temperature of the thermally conductive insulating layer in order to detect a temperature of at least one of the photovoltaic connections based on the temperature of the thermally conductive insulating layer.

Description

TECHNICAL FIELDThis application relates to the field of photovoltaic power generation, and more particularly to a photovoltaic inverter and a temperature sensing device.BACKGROUNDPhotovoltaic power generation is a technology for converting light energy into electric energy using a photovoltaic effect of a semiconductor interface. A photovoltaic system may typically include a photovoltaic module, a photovoltaic port, an inverter, an AC power distribution device, and the like. The photovoltaic module is usually mounted on a photovoltaic rack which is fixedly supported on the ground to generate power at a fixed location. In order to obtain a high output voltage or a high output current, a photovoltaic unit is usually a photovoltaic string formed by connecting a plurality of photovoltaic modules in series and / or in parallel.Currently, each photovoltaic module is connected to a photovoltaic inverter or a photovoltaic DC combiner box using a photovoltaic port (also referred to as a connector). A photovoltaic panel transmits, through a reliable electrical connection, a current output from a photovoltaic module to the inside of the photovoltaic inverter or the photovoltaic DC combiner box to implement current reversal, so that electric energy enters a panel user or is connected to a power grid. An existing photovoltaic terminal wiring process is specifically: stripping a cable and then using a cable specific tool to separately crimp the stripped portions of the cable on two sides of the photovoltaic terminal, wherein one side of the cable is connected to a photovoltaic module and the other side of the cable is connected to a photovoltaic inverter or a photovoltaic DC combiner box. If the photovoltaic terminal and the cable are poorly crimped, too large contact resistance is likely to occur, causing heating and even aging and a fire.Currently, there is no implementation solution for detecting a temperature of a photovoltaic junction connected between a photovoltaic module and an inverter. In view of this, a photovoltaic inverter needs to be designed to monitor an actual temperature of the photovoltaic panel in real time before the photovoltaic panel catches fire to ensure the reliability of power generation of an entire system.SUMMARYThis application provides a photovoltaic inverter and a temperature sensing device. A temperature of a photovoltaic panel is detected using a temperature detection circuit to monitor an actual temperature of the photovoltaic panel in real time before the photovoltaic panel catches fire to ensure the reliability of power generation of the entire photovoltaic inverter. According to a first aspect, this application provides a photovoltaic inverter. The photovoltaic inverter includes: a plurality of photovoltaic terminals, a converter, a circuit board, a temperature detection circuit, and a controller. A plurality of photovoltaic modules are configured to be respectively connected to the plurality of photovoltaic junctions. The printed circuit board comprises an electrically conductive layer and at least one thermally conductive insulation layer. One end of each photovoltaic terminal is soldered to the circuit board and the other end is connected to a corresponding photovoltaic module in a thermally conductive manner. The electrically conductive layer is configured to transfer electrical energy generated by each photovoltaic module to the converter. Each thermally conductive insulation layer is configured to conduct heat generated by at least one photovoltaic terminal. The temperature sensing circuit is configured to sense a temperature of each thermally conductive insulation layer. The controller is configured to obtain a temperature of each of the plurality of photovoltaic junctions based on the temperature of each thermally conductive insulation layer.The photovoltaic inverter provided in this application is used so that heat generated by each photovoltaic terminal can be conducted using the at least one thermally conductive insulation layer and the heat can be finally conducted to the temperature detection circuit; and the temperature of each of the plurality of photovoltaic terminals is obtained by detecting the temperature of each thermally conductive insulation layer to avoid a problem of aging, overtemperature, and fire caused by poor crimping of the photovoltaic terminals.In one possible implementation, the circuit board comprises, between each photovoltaic terminal and the temperature sensing circuit, a thermally conductive path consisting of the thermally conductive insulation layer and solder joints at which the plurality of photovoltaic terminals is connected to the circuit board. Each photovoltaic terminal is soldered to the circuit board to form a plurality of solders, and each thermally conductive insulation layer is configured to be connected to at least one solder to form the thermally conductive path consisting of the thermally conductive insulation layer and the solders formed between the photovoltaic terminals and the circuit board, so that the temperature detection circuit determines the temperature of each photovoltaic terminal by detecting different thermally conductive insulation layers. With this design, a quantity of temperature detection circuits can be significantly reduced and the temperature detection cost is reduced. Each thermally conductive insulation layer comprises a thermally conductive material and the thermally conductive material is coated with an insulation material.In one possible implementation, the thermally conductive material comprises one or more of graphite, copper foil or aluminum foil and the insulation material comprises one or more of epoxy resin, silicone rubber, insulation ceramic or glass.In one possible implementation, the thermally conductive material forms a thermally conductive layer, the insulating material forms an insulating layer, an upper surface and a lower surface of the thermally conductive layer are separately laminated with the insulating layer to form the thermally conductive insulating layer, and the insulating layer coats and is fixed to the laminated thermally conductive layer.Since the plurality of photovoltaic terminals and the converter are respectively disposed on two sides of the circuit board, when only one temperature detection circuit is disposed, the temperature detection circuit is easily affected by an external ambient temperature, causing an error in temperature detection. In one possible implementation, the temperature detection circuit comprises in particular a first temperature detection circuit and a second temperature detection circuit. The plurality of photovoltaic junctions and the converter are disposed on two sides of the circuit board. The circuit board includes a first thermally conductive insulation layer and a second thermally conductive insulation layer, the first thermally conductive insulation layer is proximate a side of the converter, and the second thermally conductive insulation layer is proximate a side of the photovoltaic junctions. The first temperature sensing circuit is configured to sense a temperature of the first thermally conductive insulation layer. The second temperature sensing circuit is configured to sense a temperature of the second thermally conductive insulation layer. The controller is configured to obtain the temperature of each of the plurality of photovoltaic junctions based on the temperatures of the first thermally conductive insulation layer and the second thermally conductive insulation layer.A thermally conductive path between the photovoltaic terminal and the first temperature sensing circuit or the second temperature sensing circuit may be: the photovoltaic terminal (plug point) - the solder joints formed between the photovoltaic terminal and the circuit board - the first temperature sensing circuit or the second temperature sensing circuit. With this design, an overall design of the temperature detection circuit is simple and feasible, the temperature detection is performed using the first temperature detection circuit and the second temperature detection circuit, and the temperature detection is more accurate.In one possible implementation, the photovoltaic inverter further comprises: a housing structure and a mounting plate. The housing structure is provided with a notch. The transducer is disposed within the housing structure. The mounting plate is provided with through holes for penetrating the photovoltaic terminals. The mounting plate is configured to be mounted to the housing structure and to clog the notch.During specific assembly, the housing structure and the mounting plate may be fixed by soldering or bonding or using a screw. Alternatively, in some possible implementations, the housing structure and the mounting plate may be an integrated structure. Before the plurality of photovoltaic terminals are soldered to the circuit board, the plurality of photovoltaic terminals may be first fixed to the mounting board to position arrangement positions of the plurality of photovoltaic terminals to facilitate soldering between the photovoltaic terminals and the circuit board. After the photovoltaic terminals and the circuit board are soldered, an overall structure including the photovoltaic terminals, the circuit board, and the mounting plate is mounted in the notch of the housing structure.In one possible implementation, sealing means or separator plates are disposed in gaps between the photovoltaic junctions and the through holes such that a sealed environment is formed within the housing structure. Since there is a cooling device such as a fan inside the case structure to reduce the effect of the fan on the temperature detection of the circuit board and the temperature detection circuit, the sealing means or the partition plates are disposed in the gaps between the photovoltaic terminals and the through holes, so that the sealed environment is formed inside the case structure.In one possible implementation, each photovoltaic terminal includes a plate end terminal, a cable end terminal, a first electrically conductive core, a second electrically conductive core, a first electrically conductive cable, and a second electrically conductive cable. A channel penetrating two ends of the plate end terminal is provided in the plate end terminal, the first electrically conductive core is slidably disposed in the channel of the plate end terminal, one end of the first electrically conductive cable is crimped to the first electrically conductive core, and the other end of the first electrically conductive cable is soldered to the circuit board. A channel penetrating two ends of the cable end terminal is provided in the cable end terminal, the second electrically conductive core is slidably disposed in the channel of the cable end terminal, one end of the second electrically conductive cable is crimped to the second electrically conductive core, and the other end of the second electrically conductive cable is connected to the photovoltaic module. After the plate end terminal is connected to the cable end terminal, the first electrically conductive core electrically connects to the second electrically conductive core, so that a current output from the photovoltaic module is input to the converter using the photovoltaic terminal.In order to reduce heat loss on the thermally conductive path, in one possible implementation, the photovoltaic inverter further comprises: a pluggable temperature sensing circuit. The pluggable temperature sensing circuit is disposed at a position where the panel end terminal and the cable end terminal are connected in the photovoltaic terminal, and is configured to sense the temperature of the photovoltaic terminal.The plug-in temperature sensing circuit is adjacent a photovoltaic terminal. This can greatly reduce heat loss on a conduction path and can reflect the temperature of the photovoltaic terminal to a maximum extent to make temperature protection more accurate. The plug-in corner temperature detection circuit is disposed at a position where the panel end terminal and the cable end terminal are connected in the corresponding photovoltaic terminal to detect the temperature of the photovoltaic terminal.In addition, in a possible implementation, when the temperature detection circuit is disposed on the circuit board, the temperature detection circuit should be disposed at a position as far away from a circuit having a large through-current as possible, in order to reduce a temperature detection error caused by heating due to thermal action.When the temperature detection circuit needs to be disposed on the circuit having a large through-current, the self-heating on the circuit board can also be reduced by adding a groove or a protrusion on the circuit, and the through-current heating can be reduced by increasing a width of an electrically conductive material at a position having a large through-current.According to a second aspect, this application provides a temperature detection device applied to a photovoltaic inverter. The temperature detection device includes a temperature detection circuit, a circuit board, and a controller. The photovoltaic inverter includes a plurality of photovoltaic terminals and a converter. The plurality of photovoltaic junctions is configured to be respectively connected to a plurality of photovoltaic modules. The printed circuit board comprises an electrically conductive layer and at least one thermally conductive insulation layer. One end of each photovoltaic terminal is soldered to the circuit board and the other end is connected to a corresponding photovoltaic module in a thermally conductive manner. The electrically conductive layer is configured to transfer electrical energy generated by each photovoltaic module to the converter. Each thermally conductive insulation layer is configured to conduct heat generated by at least one photovoltaic terminal. The temperature sensing circuit is configured to sense a temperature of each thermally conductive insulation layer.These or other aspects of this application are more brief and easier to understand in descriptions of the following embodiments.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a diagram 1 of a structure of a photovoltaic inverter; FIG. 2 is a diagram of a thermally conductive path between a photovoltaic terminal and a temperature sensing circuit; FIG. 3 is a diagram 2 of a structure of a photovoltaic inverter; FIG. 4 is a diagram of a structure of a package structure; FIG. 5 is a diagram 1 of a structure of a photovoltaic junction; and FIG. 6 is a diagram 2 of a structure of a photovoltaic junction.DESCRIPTION OF EMBODIMENTSIn order to clarify the objects, technical solutions, and advantages of this application, this application will be described in more detail below with reference to the accompanying drawings. However, example implementations may be implemented in a variety of forms and should not be construed as limited to the implementations described herein. On the contrary, these implementations are provided so that this application is more comprehensive and complete, and fully convey the concept of the example implementations to those skilled in the art. Identical reference numerals in the accompanying drawings denote identical or similar structures. Therefore, repeated description thereof will be omitted. Terms of positions and directions in this application will be described using the accompanying drawings as an example. However, changes may be made as desired, and all changes fall within the scope of this application. The accompanying drawings in this application are used only to illustrate relative positional relationships and do not represent an actual scale.In order to clarify the objects, technical solutions, and advantages of this application, this application will be described in more detail below with reference to the accompanying drawings. A specific operation method in a method embodiment may also be applied to a device embodiment or a system embodiment. It should be noted that in descriptions of this application, "at least one" means one or more and "a plurality of" means two or more. In view of this, in embodiments of the present invention, "a plurality of" may also be understood as "at least two". The term "and / or" describes an association relationship between associated objects and indicates that three relationships may exist. For example, A and / or B may represent the following three cases: only A exists, both A and B exist, and only B exists. In addition, unless otherwise indicated, the character " / " generally indicates an "or" relationship between the associated objects. In addition, it should be understood that in the description of this application, terms such as "first" and "second" are used only for distinction and description, but should not be understood as indicating or implying a relative meaning or should not be understood as indicating or implying a sequence.It should be noted that in embodiments of this application, "connection" means an electrical connection and a connection between two electrical elements may be a direct or indirect connection between the two electrical elements. For example, a connection between A and B may be a direct connection between A and B, or may be an indirect connection between A and B through one or more other electrical elements. For example, the connection between A and B may also represent that A is directly connected to C, C is directly connected to B, A and B are connected by C.In a photovoltaic system, a DC power source is generally formed by a photovoltaic module on a DC side. The photovoltaic module is connected to a DC combiner box using a photovoltaic junction. Streams of module strings are converged using the DC combiner box and connected to a converter. The converter converts a direct current generated by the photovoltaic module into an alternative current, and the alternating current is connected to a power grid to complete a photovoltaic power generation process.With an increasing wide application of photovoltaic power generation, an increasing number of problems of the photovoltaic system are exposed to humans, and a serious problem is a fire problem caused by the photovoltaic system that may cause huge losses of human body and capacity.There are many reasons for a fire of the photovoltaic system, for example a fire caused by a hot spot effect generated by the photovoltaic module. The hot spot effect is as follows: When a photovoltaic module in a series branch is shaded, the photovoltaic module is considered a load that consumes energy generated by another illuminated photovoltaic module. As a result, the shaded photovoltaic module heats up. Consequently, a local current and voltage of the photovoltaic module increase, and a local temperature rise occurs at the photovoltaic module. This causes spontaneous combustion of the photovoltaic module.For another example, if a cable connected to the photovoltaic terminal is poorly crimped, too large a contact resistance is likely to occur, causing heating of a DC arc and even aging and a fire; or if a cable connected to the photovoltaic terminal is soldered to the converter or the photovoltaic module, if an area of a solder is too small, the resistance is also increased to cause a fire.Currently, there are some temperature sensing and protection solutions for the photovoltaic module, but there is no implementation solution provided for performing temperature sensing on a photovoltaic terminal connected between the photovoltaic module and the converter. In view of this, this application provides a photovoltaic inverter to monitor an actual temperature of the photovoltaic terminal in real time before the photovoltaic terminal catches fire to ensure the reliability of an entire system.FIG. 1 is a diagram 1 of a structure of a photovoltaic inverter. The photovoltaic inverter 101 includes: a plurality of photovoltaic terminals 103, a converter 104, a printed circuit board (PCB) 105, a temperature detection circuit 106, and a controller 107. The plurality of photovoltaic junctions 103 is configured to be respectively connected to a plurality of photovoltaic modules 102.The circuit board 105 comprises: an electrically conductive layer 1051 and at least one thermally conductive insulation layer 1052. One end of each photovoltaic terminal 103 is soldered to the circuit board 105, and the other end is connected to a corresponding photovoltaic module 102 in a thermally conductive manner. The electrically conductive layer 1051 is configured to transfer electrical energy generated by each photovoltaic module 102 to the converter 104. Each thermally conductive insulation layer 1052 is configured to conduct heat generated by at least one photovoltaic terminal 103.The temperature detection circuit 106 is configured to detect a temperature of each thermally conductive insulation layer 1052. The controller 107 is configured to obtain a temperature of each of the plurality of photovoltaic junctions 103 based on the temperature of each thermally conductive insulation layer 1052.The photovoltaic module 102 converts solar energy into electrical energy using a photovoltaic effect, and the converter 104 converts the electrical energy output by the photovoltaic module 102 into an appropriate alternating current or direct current and supplies the current to a power grid or load.The photovoltaic module 102 is connected to the converter 104 using the photovoltaic terminal 103 (a connector structure). The photovoltaic terminal 103 has low contact resistance and has performance such as waterproof, high-temperature resistance, corrosion resistance, and high insulation. The circuit board 105 may be any suitable type of circuit board, for example, a multilayer circuit board, a flexible circuit board, a rigid circuit board, or a rigid-flexible circuit board. The electrically conductive layer 1051 may be a copper bus bar, an aluminum bus bar, a copper-plated aluminum bus bar, or a laminated body of copper and / or aluminum, or may be an electrically conductive bus bar, an electrically conductive plate, or a laminated body of another electrically conductive material. This is not specifically limited herein.The thermally conductive insulation layer 1052 may specifically include an insulation layer and a thermally conductive layer (not specifically shown in FIG. 1 ). A material of the insulation layer includes, but is not limited to, materials such as epoxy resin, silicone rubber, insulation ceramic, and glass, and a composite material of two or more of these materials. The thermally conductive layer may be one or more of graphite, copper foil, or aluminum foil, wherein the copper foil may be a Direct Bonding Copper (DBC), an Active Metal Bonding (AMB), or the like.An upper surface and a lower surface of the thermally conductive layer are separately laminated with the insulating layer, and the insulating layer coats and fixes the laminated thermally conductive layer to form the thermally conductive insulating layer. The circuit board 105 may further include a plurality of adhesive layers. The adhesive layers may be separately disposed between the electrically conductive layer 1051 and the thermally conductive insulation layer 1052 to bond the electrically conductive layer 1051 and the thermally conductive insulation layer 1052 to each other. The adhesive layers may be made of an acrylic adhesive or an epoxy adhesive or may be made of another suitable adhesive material. In addition, another auxiliary fastener may also be provided, for example, a clamping component is provided to secure a plurality of different layers of material in the circuit board 105 to each other. This is not specifically limited herein.The temperature detection circuit 106 may include a temperature detection device such as a thermistor or an infrared temperature detection sensor. The thermistor may be, in particular, one of a positive temperature coefficient (PTC) thermistor whose resistance value changes positively with a change in temperature, or a negative temperature system (NTC) thermistor whose resistance value changes inversely with a change in temperature. In addition, a plurality of temperature detection circuits 106 may be arranged to respectively detect temperatures of the thermally conductive insulation layers 1052.The controller 107 may be a general purpose central processing unit (CPU), a general purpose processor, digital signal processing (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The controller may implement or execute various exemplary logical blocks, modules, and circuits described with reference to the content disclosed in this application. Alternatively, the processor may be a combination that implements a computational function, for example, a combination of one or more microprocessors or a combination of a DSP and a microprocessor. Additionally, the controller 107 may further include an analog-to-digital converter (ADC) configured to convert an analog input sensed by the temperature sensing circuit 106 to a digital quantity to determine the temperature of each photovoltaic terminal 103.Two ends of the photovoltaic panel 103 are connected to a cable, and are respectively connected to the photovoltaic module 102 and the converter 104 through the cable. Specifically, after the cable is stripped, the stripped portions of the cable may be separately connected to the two ends of the photovoltaic terminal 103 using a specialized crimping tool. However, when the cable is poorly crimped to the photovoltaic terminal 103, in a least severe case, the internal resistance on a DC side is easily affected, thus reducing the power generation efficiency of the photovoltaic inverter 101; or in a severe case, poor contact is caused and thus causes the photovoltaic terminal 103 to be heated or even burned, and further causes the converter 104 to be burned, or in the worst case, causes a fire to a large extent.The photovoltaic terminal 103 should be mounted in a position away from sunlight, rain, or the like in order to avoid aging of an interface in the photovoltaic terminal 103 or rust of the cable. However, as photovoltaic technologies develop, a capacity of a single photovoltaic module 102 also increases, and an output current of the photovoltaic module 102 also gradually increases. In a process of mounting and using the photovoltaic panel 103, an increasing amount of the photovoltaic panels 103 is melted and burned, or even burning of the converter 104 is caused. Therefore, in this application, the temperature detection circuit 106 performs real-time temperature detection on the photovoltaic terminal 103 to indirectly determine a crimp status of the photovoltaic terminal 103 to ensure that the photovoltaic inverter 101 can operate normally.FIG. 2 is a diagram of a thermally conductive path between a photovoltaic terminal and a temperature sensing circuit. Each photovoltaic terminal 103 is soldered to the circuit board 105 to form a plurality of solders. Between each photovoltaic terminal 103 and the temperature detection circuit 106, the circuit board 105 includes a thermally conductive path consisting of a plurality of solders at which the photovoltaic terminal 103 is connected to the circuit board 105 and the thermally conductive insulation layer 1052, so that the temperature detection circuit 106 obtains a temperature of each photovoltaic terminal 103 by detecting different thermally conductive insulation layers 1052. With this design, a quantity of temperature detection circuits 106 can be significantly reduced and the temperature detection cost is reduced.Since the plurality of photovoltaic terminals 103 and the inverter 104 are respectively disposed on two sides of the circuit board 105, when only one temperature detection circuit 106 is disposed, the temperature detection circuit 106 is easily affected by an external ambient temperature, causing an error in temperature detection. FIG. 3 is a diagram 2 of a structure of a photovoltaic inverter. The temperature detection circuit 106 includes, in particular, a first temperature detection circuit 1061 and a second temperature detection circuit 1062. The circuit board 105 includes a first thermally conductive insulation layer 10521 and a second thermally conductive insulation layer 10522. The first thermally conductive insulation layer 10521 is near a side of the converter 104 and the second thermally conductive insulation layer 105222 is near a side of the photovoltaic junctions 103.The first temperature detection circuit 1061 is configured to detect a temperature of the first thermally conductive insulation layer 10521. The second temperature detection circuit 1062 is configured to detect a temperature of the second thermally conductive insulation layer 10522. The controller is configured to obtain a temperature of each of the plurality of photovoltaic junctions 103 based on the temperatures of the first thermally conductive insulation layer 10521 and the second thermally conductive insulation layer 10522.Since a cable crimped to the photovoltaic terminal 103 is soldered to the circuit board 105, the first temperature detection circuit 1061 can detect a temperature of a side on which solders are formed between the photovoltaic terminal 103 and the circuit board 105, and the second temperature detection circuit 1062 can detect a temperature of a side other than the side on which the solders are formed between the photovoltaic terminal 103 and the circuit board 105.In this way, a thermally conductive path between the photovoltaic terminal 103 and the first temperature sensing circuit 1061 or the second temperature sensing circuit 1062 may be: the photovoltaic terminal 103 (plug point) - the solder joints formed between the photovoltaic terminal 103 and the circuit board 105 - the first temperature sensing circuit 1061 / the second temperature sensing circuit 1062. With this design, an overall design of the temperature detection circuit 106 is simple and feasible, the temperature detection is performed using the first temperature detection circuit 1061 and the second temperature detection circuit 1062, and the temperature detection is more accurate.FIG. 4 is a diagram of a structure of a package structure. The photovoltaic inverter 101 further includes: the case structure 400 and a mounting plate 401. The housing structure 400 is provided with a notch 402. The transducer 104 is disposed within the housing structure 400 (not shown in FIG. 4 ). The mounting plate 401 is provided with through holes 403 for penetrating each photovoltaic terminal 103. The mounting plate 401 is configured to be mounted to the housing structure 400 and to block the notch 402.During the specific mounting, the housing structure 400 and the mounting plate 401 may be fixed by soldering or bonding or using a screw. Alternatively, the housing structure 400 and the mounting plate 401 may be an integrated structure in some possible implementations. For example, the mounting plate 401 may be formed in a manner such as die casting or die casting to produce the housing structure 400 and the mounting plate 401 as an integrated mechanical part. In particular, before the plurality of photovoltaic terminals 103 is soldered to the circuit board 105, the plurality of photovoltaic terminals 103 may be first fixed to the mounting board 401 to position arrangement positions of the plurality of photovoltaic terminals 103 to facilitate soldering between the photovoltaic terminals 103 and the circuit board 105. After the photovoltaic terminals 103 and the circuit board 105 are soldered, an overall structure including the photovoltaic terminals 103, the circuit board 105, and the mounting plate 401 is mounted in the notch 402 of the case structure 400.Since there is a cooling device such as a fan inside the case structure 400 to reduce the effect of the cooling device on temperature sensing of the circuit board and the temperature sensing circuit 106, sealing means or separation plates may be disposed in gaps between the photovoltaic junctions 103 and the through holes, so that a sealed environment is formed inside the case structure 400.In one possible implementation, FIG. 5 is a diagram 1 of a structure of a photovoltaic junction. Each photovoltaic terminal 103 may in particular comprise a plate end terminal 1031, a cable end terminal 1032, a first electrically conductive core 1033, a second electrically conductive core 1034, a first electrically conductive cable 1035 and a second electrically conductive cable 1036. A channel penetrating two ends of the plate end terminal 1031 is provided in the plate end terminal 1031, the first electrically conductive core 1033 is slidably disposed in the channel of the plate end terminal 1031, one end of the first electrically conductive cable 1035 is crimped onto the first electrically conductive core 1033, and the other end of the first electrically conductive cable 1035 is soldered onto the circuit board 105. A channel penetrating two ends of the cable end terminal 1032 is provided in the cable end terminal 1032, the second electrically conductive core 1034 is slidably disposed in the channel of the cable end terminal 1032, one end of the second electrically conductive cable 1036 is crimped onto the second electrically conductive core 1034, and the other end of the second electrically conductive cable 1036 is connected to the photovoltaic module 102.In order to reduce heat loss on a thermally conductive path, FIG. 6 is a diagram 2 of a structure of a photovoltaic connector in one possible implementation. The photovoltaic inverter 101 further includes a plug-in temperature sensing circuit 601. The pluggable temperature detection circuit 601 is disposed at a position where the plate end terminal 1031 and the cable end terminal 1032 are connected in the photovoltaic terminal, and is configured to detect a temperature of the photovoltaic terminal 103.The pluggable temperature sensing circuit 601 is adjacent to the photovoltaic port 103. This can greatly reduce heat loss on a conduction path and can reflect the temperature of the photovoltaic terminal 103 to a maximum extent to make temperature protection more accurate. The pluggable temperature detection circuit 601 is disposed at the position where the plate end terminal 1031 and the cable end terminal 1032 are connected in the corresponding photovoltaic terminal 103 to detect the temperature of the photovoltaic terminal 103.In addition, in a possible implementation, when the temperature detection circuit 106 is disposed on the circuit board 105, the temperature detection circuit 106 should be disposed at a position as far away from a circuit having a large through-current as possible, in order to reduce a temperature detection error caused by heating due to thermal action.When the temperature sensing circuit 106 needs to be disposed on the circuit having a large through-current, the self-heating on the circuit board 105 can also be reduced by adding a groove or a protrusion on the circuit, and the through-current heating can be reduced by increasing a width of an electrically conductive material at a position having a large through-current.The photovoltaic inverter provided in this application is used so that heat generated by each photovoltaic terminal can be conducted using the at least one thermally conductive insulation layer and the heat can be finally conducted to the temperature detection circuit; and the temperature of each of the plurality of photovoltaic terminals is obtained by detecting the temperature of each thermally conductive insulation layer to avoid a problem of aging, overtemperature, and fire caused by poor crimping of the photovoltaic terminals.Based on a same idea, this application further provides a temperature detection device applied to the photovoltaic inverter 101. The temperature detection device includes a temperature detection circuit, a circuit board, and a controller. The photovoltaic inverter includes a plurality of photovoltaic terminals and a converter. The plurality of photovoltaic junctions is configured to be respectively connected to a plurality of photovoltaic modules. The printed circuit board comprises an electrically conductive layer and at least one thermally conductive insulation layer. One end of each photovoltaic terminal is soldered to the circuit board and the other end is connected to a corresponding photovoltaic module in a thermally conductive manner. The electrically conductive layer is configured to transfer electrical energy generated by each photovoltaic module to the converter. Each thermally conductive insulation layer is configured to conduct heat generated by at least one photovoltaic terminal. The temperature sensing circuit is configured to sense a temperature of each thermally conductive insulation layer.The foregoing descriptions are merely specific implementations of this application, but are not intended to limit the scope of this application. Any variation or substitution readily found by one skilled in the art within the technical scope disclosed in this application is intended to fall within the scope of this application. Therefore, the scope of this application is subject to the scope of the claims.

Claims

A photovoltaic inverter, the photovoltaic inverter comprising: a plurality of photovoltaic terminals, a converter, a circuit board, a temperature sensing circuit, and a housing structure; wherein the converter and the circuit board are disposed within the housing structure; wherein the photovoltaic terminals each penetrate the housing structure and have one end within the housing structure electrically connected to the circuit board and another end outside the housing structure configured to be connected to a photovoltaic module; wherein the circuit board comprises an electrically conductive layer and a thermally conductive insulation layer, wherein the electrically conductive layer is configured to transfer electrical energy generated by the plurality of photovoltaic modules to the converter, and the thermally conductive insulation layer is configured to conduct heat generated by the photovoltaic terminal to the temperature sensing circuit; wherein the temperature sensing circuit is configured to sense a temperature of the thermally conductive insulation layer to sense a temperature of at least one of the photovoltaic terminals based on the temperature of the thermally conductive insulation layer.A photovoltaic inverter, the photovoltaic inverter comprising: a plurality of photovoltaic terminals, a converter, a circuit board, a temperature sensing circuit, and a housing structure; wherein the converter and the circuit board are disposed within the housing structure; wherein the photovoltaic terminals penetrate the housing structure, and each photovoltaic terminal has one end within the housing structure that is electrically connected to the circuit board and another end outside the housing structure that is configured to be connected to a photovoltaic module; wherein the circuit board comprises an electrically conductive layer and a thermally conductive insulation layer, wherein the electrically conductive layer is configured to transfer electrical energy generated by the plurality of photovoltaic modules to the converter, and the thermally conductive insulation layer is configured to conduct heat generated by the photovoltaic terminal to the temperature sensing circuit; wherein the temperature sensing circuit is disposed on the circuit board and thermally connected to the thermally conductive insulation layer.The photovoltaic inverter of claim 2, wherein between one of the photovoltaic terminals and the temperature sensing circuit, the circuit board comprises a thermally conductive path consisting of the thermally conductive insulation layer and a connection location at which the one of the photovoltaic terminals is electrically connected to the circuit board.The photovoltaic inverter according to claim 2 or 3, wherein each thermally conductive insulation layer comprises a thermally conductive material, and the thermally conductive material is coated with an insulation material.The photovoltaic inverter of claim 4, wherein the thermally conductive material comprises one or more of graphite, copper foil or aluminum foil, the insulation material comprises one or more of epoxy resin, silicone rubber, insulation ceramic or glass.The photovoltaic inverter according to claim 4, wherein the thermally conductive material forms a thermally conductive layer, the insulating material forms an insulating layer, an upper surface and a lower surface of the thermally conductive layer are separately laminated with the insulating layer to form the thermally conductive insulating layer, and the insulating layer coats and fixes the laminated thermally conductive layer.The photovoltaic inverter according to any one of claims 2 to 6, wherein the temperature sensing circuit specifically comprises a first temperature sensing circuit and a second temperature sensing circuit, the plurality of photovoltaic terminals and the converter are respectively disposed on two sides of the circuit board, the circuit board comprises a first thermally conductive insulation layer and a second thermally conductive insulation layer, the first thermally conductive insulation layer is close to one side of the converter, and the second thermally conductive insulation layer is close to one side of the plurality of photovoltaic terminals; wherein the first temperature sensing circuit is configured to sense a temperature of the first thermally conductive insulation layer; wherein the second temperature sensing circuit is configured to sense a temperature of the second thermally conductive insulation layer; and wherein the controller is configured to obtain the temperature of each of the plurality of photovoltaic terminals based on the temperatures of the first thermally conductive insulation layer and the second thermally conductive insulation layer.The photovoltaic inverter according to any one of claims 2 to 7, wherein the photovoltaic inverter further comprises a mounting plate, the case structure is provided with a notch, the converter is disposed inside the case structure, the mounting plate is provided with through holes for penetrating the photovoltaic terminals, and the mounting plate is configured to be mounted to the case structure and clog the notch.The photovoltaic inverter of claim 8, wherein sealing means or separator plates are disposed in gaps between the photovoltaic junctions and the through holes such that a sealed environment is formed within the housing structure.The photovoltaic inverter according to any one of claims 2 to 9, wherein each photovoltaic terminal comprises a plate end terminal, a cable end terminal, a first electrically conductive core, a second electrically conductive core, a first electrically conductive cable, and a second electrically conductive cable; a channel penetrating two ends of the plate end terminal is provided in the plate end terminal, the first electrically conductive core is slidably disposed in the channel of the plate end terminal, one end of the first electrically conductive cable is crimped to the first electrically conductive core, and the other end of the first electrically conductive cable is soldered to the circuit board; a channel penetrating two ends of the cable end terminal provided in the cable end terminal, the second electrically conductive core slidably disposed in the channel of the cable end terminal, one end of the second electrically conductive cable is crimped onto the second electrically conductive core, and the other end of the second electrically conductive cable is connected to the photovoltaic module; and after the plate end terminal is connected to the cable end terminal, the first electrically conductive core makes an electrical connection with the second electrically conductive core, so that a current output from the photovoltaic module is input to the converter using the photovoltaic terminal.The photovoltaic inverter of claim 10, wherein the photovoltaic inverter further comprises a pluggable temperature sensing circuit, wherein the pluggable temperature sensing circuit is disposed at a plug position between the panel end terminal and the cable end terminal in the photovoltaic terminal and is configured to sense a temperature at the plug position of the photovoltaic terminal.The photovoltaic inverter of claim 2, wherein the one end of the photovoltaic terminal inside the case structure is electrically connected to the circuit board by soldering, and the other end of the photovoltaic terminal outside the case structure is configured to be connected to photovoltaic modules in a plus-in manner.The photovoltaic inverter of claim 12, wherein the thermally conductive insulation layer is offset on the circuit board and is disposed between the temperature sensing circuit and the junction at which one of the photovoltaic junctions is connected to the circuit board.A temperature sensing device applied to a photovoltaic inverter, the temperature sensing device comprising a temperature sensing circuit, a printed circuit board, and a controller, wherein the photovoltaic inverter comprises a plurality of photovoltaic terminals and a converter, and the plurality of photovoltaic terminals is configured to be connected to a plurality of photovoltaic modules, respectively; wherein the printed circuit board comprises an electrically conductive layer and a thermally conductive insulation layer, one end of each photovoltaic terminal being connected to the printed circuit board; wherein the electrically conductive layer is configured to transfer electrical energy generated by the photovoltaic modules to the converter, and the thermally conductive insulation layer is configured to conduct heat generated by at least one photovoltaic terminal to the temperature sensing circuit; and wherein the temperature sensing circuit is configured to sense a temperature of each thermally conductive insulation layer.The temperature sensing device of claim 14, wherein the thermally conductive insulation layer is mounted in the circuit board and is located between the temperature sensing circuit and the junction at which at least one of the photovoltaic junctions is connected to the circuit board.

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