A photovoltaic inverter

Abstract

The application provides a photovoltaic inverter. The photovoltaic inverter comprises a housing, a circuit board and a power conversion circuit. An inner space of the housing is divided into multiple accommodation cavities. The multiple accommodation cavities comprise a first accommodation cavity. A switching tube of the power conversion circuit is located in the first accommodation cavity, and an electronic device is arranged between the switching tube and a terminal panel. At least one heat dissipation fin is arranged on an outer surface of the housing away from the cover. Each heat dissipation fin extends in a direction perpendicular to the terminal panel and is arranged opposite to the switching tube. The height of the at least one heat dissipation fin in a direction perpendicular to the outer surface is constant. When the photovoltaic inverter is installed, the heat dissipation fin is located between the housing and a mounting surface. Therefore, when air flows along the heat dissipation fin, the air flows through the flat outer surface of the housing without being blocked by the housing, and the heat dissipation effect can be improved.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and in particular to a photovoltaic inverter. Background Technology

[0002] In a photovoltaic (PV) system, a PV inverter is used to convert the direct current (DC) generated by PV modules into alternating current (AC), and then supply the AC power to the grid or load. A PV inverter consists of a housing and a circuit board located inside the housing, which houses power conversion devices and switching devices. When the PV inverter is operating, the power conversion devices and switching devices generate heat, which is transferred to the outside of the PV inverter through the housing.

[0003] To improve the heat dissipation efficiency of photovoltaic inverters, multiple heat dissipation fins are typically provided on the outer surface of the casing closest to the devices. However, due to the different sizes of power devices and switching devices, the aforementioned outer surface of the casing has protrusions of varying depths. Consequently, the height and length of the multiple heat dissipation fins arranged on this outer surface also differ, resulting in uneven heat dissipation area and thus affecting the heat dissipation efficiency of the photovoltaic inverter. Utility Model Content

[0004] This application provides a photovoltaic inverter to improve the heat dissipation effect of a photovoltaic inverter with an inverted circuit structure.

[0005] In a first aspect, this application provides a photovoltaic inverter. The photovoltaic inverter includes a housing, a circuit board, and a power conversion circuit, with the circuit board and power conversion circuit located within the housing. Specifically, the housing includes a cover and a casing, with the cover fitting over the casing. The circuit board is located between the cover and the casing, and the plane of the circuit board is parallel to the surface of the casing opposite the cover. The casing or cover includes a terminal panel, which is provided with DC input terminals and AC output terminals. The casing is provided with multiple partitions extending from the casing toward the circuit board and dividing the space between the casing and the circuit board into multiple receiving cavities. The multiple receiving cavities include a first receiving cavity. The power conversion circuit includes at least one switching transistor. The at least one switching transistor is located within the first receiving cavity, and at least one electronic device is disposed between the at least one switching transistor and the terminal panel. At least one heat dissipation fin is provided on the outer surface of the casing on the side away from the cover. The at least one heat dissipation fin is located opposite the at least one switching transistor on both sides of the casing, and the at least one heat dissipation fin extends in a direction perpendicular to the terminal panel. The height of the at least one heat dissipation fin in the direction perpendicular to the outer surface is constant.

[0006] In the embodiments of this application, the photovoltaic inverter adopts an inverted-top structure to simplify the cable design of the power conversion circuit. Compared to a power conversion circuit that is conventionally positioned within the housing (e.g., electronic components such as switching transistors, inductors, and bus capacitors are located between the circuit board and the cover), the inverted-top structure results in a shorter distance between the heat-generating components and the housing. This means a shorter heat transfer distance between the heat-generating components and the heat sink fins. The housing can directly transfer the heat generated by the heat-generating components to the heat sink fins, which then dissipate the heat, thus accelerating heat dissipation within the photovoltaic inverter. The height of the heat sink fins is the dimension between the end and the root of the fin along a direction perpendicular to the outer surface. When the photovoltaic inverter is mounted on the mounting surface, at least one heat sink fin is located between the outer surface of the housing and the mounting surface, dividing the space between the outer surface and the mounting surface into multiple heat dissipation channels. These channels extend throughout the entire photovoltaic inverter along its height, allowing airflow to pass through without obstruction by the outer surface, thereby improving heat dissipation. In addition, the constant height of the heat dissipation fins makes the heat dissipation area of ​​the at least one heat dissipation fin more uniform, thereby improving the heat dissipation effect of the photovoltaic inverter with the inverted circuit structure.

[0007] In one embodiment, the projection of the portion with a constant height in each heat sink fin coincides with the at least one switching transistor and the at least one electronic device. Therefore, the switching transistor and the heat-generating electronic device between the switching transistor and the terminal panel can be cooled by heat sink fins of relatively uniform size, thereby further improving the heat dissipation efficiency.

[0008] In one embodiment, the power conversion circuit further includes a first power inductor, a second power inductor, and a bus capacitor. The at least one switching transistor includes a first switching transistor and a second switching transistor. The first power inductor, the first switching transistor, the bus capacitor, the second switching transistor, and the second power inductor are arranged sequentially in a first receiving cavity along a direction parallel to the plane of the terminal panel. The first power inductor is disposed opposite to the DC input terminal, and the second power inductor is disposed opposite to the AC output terminal. The at least one heat sink includes at least one first heat sink and at least one second heat sink arranged in parallel. The at least one first heat sink is disposed opposite to the first switching transistor, and the at least one second heat sink is disposed opposite to the second switching transistor. In this embodiment, the first switching transistor can be a DC-side switching transistor, and the second switching transistor can be an AC-side switching transistor. When the photovoltaic inverter is working, the current enters from the DC input terminal, passes through the first power inductor, the first switching transistor, the bus capacitor, the second switching transistor, and the second power inductor, and flows out from the AC output terminal, thereby forming an approximately straight current path at least on one side of the housing. This reduces the crossing of current paths, thereby reducing the impedance of the power conversion circuit.

[0009] In one embodiment, the aforementioned plurality of receiving cavities further includes a second receiving cavity and a third receiving cavity. The first, second, and third receiving cavities are respectively disposed adjacent to the terminal panel. A portion of the first receiving cavity is located between the second and third receiving cavities, and another portion of the first receiving cavity is located on the side of the second and third receiving cavities away from the terminal panel. The power conversion circuit further includes a DC-side common-mode inductor, an inverter capacitor, and an AC-side common-mode inductor. The DC-side common-mode inductor is located within the second receiving cavity and adjacent to the DC input terminal, while the AC-side common-mode inductor is located within the third receiving cavity and adjacent to the AC output terminal. A first power inductor is located on the side of the DC-side common-mode inductor away from the DC input terminal, a second power inductor is located on the side of the AC-side inductor away from the AC output terminal, and the inverter capacitor is located within the third receiving cavity and between the second power inductor and the AC-side common-mode inductor. In this embodiment, by placing the multiple electronic components of the power conversion circuit within different receiving cavities, electromagnetic interference between the multiple electronic components can be reduced, thereby improving the electromagnetic compatibility of the photovoltaic inverter, and consequently reducing the losses and improving the operating efficiency of the photovoltaic inverter. When the photovoltaic inverter is working, the current enters from the DC input terminal and passes sequentially through the DC side common-mode inductor, the first power inductor, the first switching transistor, the bus capacitor, the second switching transistor, the second power inductor, the inverter capacitor, and the AC side common-mode inductor, and flows out from the AC output terminal. That is, the current flows sequentially along the second housing cavity, the first housing cavity, and the third housing cavity, thus forming an approximately U-shaped current path inside the casing. This reduces the crossing of current paths, thereby reducing the impedance of the power conversion circuit.

[0010] In one embodiment, the AC output terminal is a single-phase output terminal. The photovoltaic inverter in this embodiment can be a single-phase photovoltaic inverter, with a relatively simple power conversion circuit structure, and can achieve less electromagnetic interference within the limited space of the casing.

[0011] In one embodiment, a control device is further disposed within the second receiving cavity. The control device is used to control the power conversion circuit. In this embodiment, the control device is located between the bus capacitor and the terminal panel. Therefore, when the bus capacitor fails and causes electrolyte leakage, the circuit containing the control device is a low-voltage circuit, which can prevent electrolyte from entering the high-voltage circuit and causing damage to the power conversion circuit.

[0012] In one embodiment, a first thermal pad is disposed between the bottom wall of the housing located in the second receiving cavity and the bus capacitor. And / or, a second thermal pad is disposed between the bottom wall of the housing located in the first receiving cavity and the DC-side common-mode inductor. And / or, a third thermal pad is disposed between the bottom wall of the housing located in the third receiving cavity and the AC-side common-mode inductor. And / or, the power conversion circuit further includes multiple relays located within the first receiving cavity and between the inverter capacitor and the AC-side common-mode inductor, and a fourth thermal pad is disposed between the bottom wall of the housing located in the first receiving cavity and the multiple relays. In this embodiment, the aforementioned thermal pads can accelerate heat exchange between the components of the power conversion circuit and the housing, thereby improving the heat dissipation rate and heat dissipation effect.

[0013] In one embodiment, the bottom wall of the housing located within the first receiving cavity is provided with a first protrusion and a second protrusion, which extend from the housing towards the circuit board. The first protrusion separates a first power inductor and a bus capacitor, and the second protrusion separates a second power inductor and a bus capacitor. A first switching transistor is disposed on the surface of the first protrusion facing the circuit board, and a second switching transistor is disposed on the surface of the second protrusion facing the circuit board. In this embodiment, when the bus capacitor fails, the electrolyte inside the bus capacitor may be ejected from the bus capacitor. The first and second protrusions can separate the first and second power inductors from the bus capacitor, thereby preventing electrolyte from entering the power inductors and damaging them.

[0014] In one embodiment, at least one first electronic device is disposed between the first switching transistor and the terminal panel, wherein the height of the at least one first electronic device in the direction perpendicular to the circuit board is less than or equal to the sum of the heights of the first switching transistor and the first boss in the direction perpendicular to the circuit board. At least one second electronic device is disposed between the second switching transistor and the terminal panel, wherein the height of the at least one second electronic device in the direction perpendicular to the circuit board is less than or equal to the sum of the heights of the second switching transistor and the second boss in the direction perpendicular to the circuit board. Thus, on the outer surface of the housing on the side away from the cover, the portion of the outer surface adjacent to the first switching transistor and the at least one first electronic device is a flat surface, and the portion of the outer surface adjacent to the second switching transistor and the at least one second electronic device is also a flat surface, thereby ensuring that the heights of both the first and second heat dissipation fins are constant.

[0015] In one embodiment, the height of each first electronic device may be less than or equal to 10 millimeters, and the height of each second electronic device may be less than or equal to 10 millimeters. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of an application scenario of a photovoltaic system provided in an embodiment of this application;

[0017] Figure 2This is a front view of the photovoltaic inverter provided in the embodiments of this application;

[0018] Figure 3 This is a schematic diagram of the back of a photovoltaic inverter provided in an embodiment of this application;

[0019] Figure 4 This is an exploded view of a photovoltaic inverter provided in an embodiment of this application;

[0020] Figure 5 A schematic diagram of the housing provided in an embodiment of this application;

[0021] Figure 6 Another schematic diagram of the housing provided in the embodiments of this application;

[0022] Figure 7 A schematic diagram of the housing layout provided for an embodiment of this application;

[0023] Figure 8 for Figure 3 A cross-sectional view of the shell along the AA direction;

[0024] Figure 9 A schematic diagram of the current path of a photovoltaic inverter during operation, provided in an embodiment of this application;

[0025] Figure 10 for Figure 7 Cross-sectional view of the middle shell along the BB direction;

[0026] Figure 11 for Figure 5 A top view of the shell along the z-direction.

[0027] Figure label:

[0028] 10-Photovoltaic System 11-Photovoltaic Module 12-Photovoltaic Inverter

[0029] 13-Energy Storage Equipment 20-Power Grid 31-Switchpipe

[0030] 32-First power inductor; 33-Second power inductor; 34-Bus capacitor

[0031] 35 - DC-side common-mode inductor; 36 - Inverter capacitor; 37 - AC-side common-mode inductor

[0032] 38-Electronic Components 39-Control Components 40-Sampling Circuits

[0033] 121-Outer shell 122-Cover 123-Shell

[0034] 124 - Heat sink fins 125 - Circuit board 126 - Terminal panel

[0035] 127 - DC input terminal; 128 - AC output terminal; 129 - Separator plate

[0036] 131-First receiving cavity 132-Second receiving cavity 133-Third receiving cavity

[0037] 134 - First boss; 135 - Second boss; 141 - First heat dissipation fin

[0038] 142 - Second heat sink 143 - Third heat sink 311 - First switching transistor

[0039] 312-Second Switch Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0041] To facilitate understanding of the photovoltaic inverter provided in this application embodiment, its application scenarios are described below. The photovoltaic inverter of this application can be applied to power supply systems and power generation systems. Taking a photovoltaic system as an example, the photovoltaic system can be used in two application scenarios: residential power stations and industrial photovoltaic power stations. The photovoltaic inverter can convert solar energy into electrical energy to supply the power grid or loads. Figure 1 This is a schematic diagram illustrating an application scenario of the photovoltaic system provided in an embodiment of this application. For example... Figure 1 As shown, the photovoltaic system 10 is applied in a home power station. Specifically, the photovoltaic module 11 is used to convert solar energy into electrical energy. The photovoltaic system 10 includes a photovoltaic inverter 12, one end of which is connected to the photovoltaic module 11, and the other end is connected to the grid 20 or the load. The photovoltaic inverter 12 is used to convert the direct current (DC) power from the photovoltaic module 11 into alternating current (AC) power and transmit the AC power to the grid 20 or the load. A photovoltaic optimizer can also be installed in the photovoltaic system 10 to improve the power generation efficiency of the photovoltaic module 11. The photovoltaic optimizer is a DC-input, DC-output module-level power electronic device. By connecting in series with the photovoltaic module 11, it uses predictive current and voltage technology to ensure that the module is always in the optimal operating state. According to the working principle of buck topology, it is used to solve the impact of shading, inconsistent orientation, or differences in module electrical specifications on the power generation of the photovoltaic power station, realize the maximum power output of the photovoltaic module 11, and thus improve the power generation of the photovoltaic system 10. Of course, the photovoltaic system 10 may also include an energy storage device 13. The alternating current converted by the photovoltaic inverter 12 can also be transmitted to the energy storage device 13 for energy storage.

[0042] In addition, a grid-connected / off-grid controller can be installed between the photovoltaic inverter 12 and the power grid 20. The photovoltaic inverter 12 converts the DC power provided by the photovoltaic modules 11 into AC power and transmits the AC power to the grid-connected / off-grid controller. The grid-connected / off-grid controller can also be electrically connected to electrical appliances. In practical applications, the grid-connected / off-grid controller has off-grid and grid-connected states. When the grid-connected / off-grid controller is in off-grid state, it is not electrically connected to the power grid 20, and the AC power transmitted by the photovoltaic inverter 12 is only supplied to electrical appliances. These electrical appliances include household appliances such as televisions, air conditioners, refrigerators, and washing machines.

[0043] When the grid-connected controller is in grid-connected mode, it is electrically connected to the grid 20 via a power sensor. When the electrical energy generated by the photovoltaic module 11 cannot meet the power demand of the electrical equipment, the grid 20 can supply electrical energy to the photovoltaic system 10 through the grid-connected controller. When the power generation of the photovoltaic module 11 exceeds the power consumption of the electrical equipment, the grid-connected controller can transmit the excess power to the grid 20. The power sensor is used to measure the power flow between the photovoltaic system 10 and the grid 20; for example, the power sensor can be an electricity meter.

[0044] As the requirements for loss and efficiency in photovoltaic systems increase, the heat dissipation requirements for photovoltaic inverters also gradually increase. Therefore, how to improve the heat dissipation effect of photovoltaic inverters has gradually become an important research issue.

[0045] In view of this, this application provides a photovoltaic inverter to improve the heat dissipation effect of a photovoltaic inverter with an inverted circuit structure.

[0046] It should be noted that the terminology used in the following embodiments is for the purpose of describing specific embodiments only and is not intended to be a limitation of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise.

[0047] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0048] In this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more.

[0049] Furthermore, in this article, directional terms such as "top," "bottom," "upper," and "lower" are defined relative to the orientation of the structure as shown in the attached drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation of the structure.

[0050] Figure 2 This is a front view of the photovoltaic inverter provided in the embodiments of this application. Figure 3 This is a schematic diagram of the back of a photovoltaic inverter provided in an embodiment of this application. Figure 2 and Figure 3 As shown, the photovoltaic inverter 12 includes a housing 121. The housing 121 includes a cover 122 and a casing 123. The cover 122 covers the casing 123, and a receiving space is formed between the cover 122 and the casing 123. In practical applications, the surface of the casing 123 away from the cover 122 is mounted on a mounting plate, with the cover 122 facing the user. Therefore, the outer surface of the casing 123 away from the cover 122 is the back side of the photovoltaic inverter 12, and the outer surface of the cover 122 away from the casing 123 is the front side of the photovoltaic inverter 12.

[0051] It should be noted that in some embodiments, the housing 123 can be a basin-shaped structure, that is, the housing 123 includes a housing bottom plate and a plurality of housing side plates, which are sequentially connected and perpendicularly connected to the outer periphery of the housing bottom plate. In this embodiment, the cover 122 can be a plate-shaped structure and is disposed opposite to the housing bottom plate, and the outer periphery of the cover 122 is connected to the aforementioned plurality of housing side plates. The cover 122 can also be a basin-shaped structure, that is, the cover 122 includes a cover bottom plate and a plurality of cover side plates, which are sequentially connected and perpendicularly connected to the outer periphery of the cover bottom plate. The cover bottom plate is disposed opposite to the housing bottom plate, and the aforementioned plurality of cover side plates are connected to the aforementioned plurality of housing side plates. In other embodiments, the cover 122 can be a basin-shaped structure. The housing 123 can be a plate-shaped structure and is disposed opposite to the cover bottom plate, and the housing 123 is connected to the plurality of cover side plates of the cover 122. In some other embodiments, the housing 123 may be a basin-shaped structure, the cover 122 may be a plate-shaped structure, and the cover is connected to a plurality of housing side plates of the housing 123.

[0052] In addition, at least one heat dissipation fin 124 is provided on the outer surface of the housing 123 on the side away from the cover 122. The heat generated by the electronic components inside the photovoltaic inverter 12 is transferred to the housing 123 and dissipated through the heat dissipation fin 124.

[0053] Figure 4 This is an exploded view of a photovoltaic inverter provided in an embodiment of this application. Figure 4 As shown, the photovoltaic inverter 12 also includes a circuit board 125 and a power conversion circuit, which are located inside the housing 121. Specifically, the circuit board 125 is located between the cover 122 and the housing 123, and the plane of the circuit board 125 is parallel to the surface of the housing 123 opposite to the cover 122. The housing 123 or the cover 122 includes a terminal panel 126, which is provided with DC input terminals 127 and AC output terminals 128.

[0054] It should be noted that in this application, the terminal panel 126 is parallel to the x and y directions and perpendicular to the z direction. The DC input terminal 127 and AC output terminal 128 are arranged on the terminal panel 126 along the x direction. The x direction is the width direction of the photovoltaic inverter 12, the y direction is the depth direction of the photovoltaic inverter 12, and the z direction is the height direction of the photovoltaic inverter 12.

[0055] Figure 5 A schematic diagram of the housing provided in an embodiment of this application. Figure 6 Another schematic diagram of the housing provided in an embodiment of this application. (See diagram below.) Figure 5 and Figure 6 As shown, the housing 123 is provided with a plurality of partition plates 129, which extend from the housing 123 toward the circuit board 125 and divide the space between the housing 123 and the circuit board 125 into a plurality of receiving cavities. The plurality of receiving cavities include a first receiving cavity 131, a second receiving cavity 132, and a third receiving cavity 133. The first receiving cavity 131, the second receiving cavity 132, and the third receiving cavity 133 are respectively disposed adjacent to the terminal panel 126. A portion of the first receiving cavity 131 is located between the second receiving cavity 132 and the third receiving cavity 133, and another portion of the first receiving cavity 131 is located on the side of the second receiving cavity 132 and the third receiving cavity 133 away from the terminal panel 126.

[0056] Figure 7 This is a schematic diagram of the housing layout provided for an embodiment of this application. (See attached diagram.) Figure 7 As shown, the power conversion circuit includes at least one switching transistor 31. The at least one switching transistor 31 is located within a first receiving cavity 131. Within the first receiving cavity 131, at least one electronic device is disposed between the switching transistor 31 and the terminal panel 126.

[0057] Figure 8 for Figure 3 A cross-sectional view of the shell along the AA direction. (See attached image.) Figure 7 and Figure 8 As shown, at least one of the aforementioned heat dissipation fins 124 and Figure 7 At least one switching tube 31 is located opposite each other on both sides of the housing 123, and the aforementioned at least one heat dissipation fin 124 extends in a direction perpendicular to the terminal panel 126. Each heat dissipation fin 124 has a projection perpendicular to the aforementioned outer surface. Along the extending direction of the heat dissipation fin 124, the height H of each heat dissipation fin 124 in the direction perpendicular to the aforementioned outer surface is constant.

[0058] In the embodiments of this application, the photovoltaic inverter 12 adopts an inverted structure to simplify the cable design of the power conversion circuit. Compared to the power conversion circuit being arranged in the forward direction within the housing 123 (e.g., the switching transistor 31, inductor, bus capacitor, and other electronic components are located between the circuit board 125 and the cover 122), in the aforementioned inverted structure, the distance between the heat-generating components and the housing 123 is shorter, meaning the heat transfer distance between the heat-generating components and the heat dissipation fins 124 is shorter. The housing 123 can directly transfer the heat generated by the heat-generating components to the heat dissipation fins 124, and the heat is dissipated through the heat dissipation fins 124, thereby accelerating the heat dissipation inside the photovoltaic inverter 12. After the photovoltaic inverter 12 is installed, the heat dissipation channel between the outer surface of the housing 123 and the mounting surface runs through the entire photovoltaic inverter 12 along the height direction of the photovoltaic inverter 12. Since the portion of the outer surface with the heat dissipation fins 124 is a flat surface, the airflow along the heat dissipation fins 124 is not obstructed by the housing 123, thereby improving the heat dissipation effect.

[0059] The height H of the heat sink fin 124 is the dimension of the heat sink fin 124 in the direction perpendicular to the outer surface, that is, the distance from the end to the root of the heat sink fin 124. Since the portion of the heat sink fin 124 projected into the first receiving cavity 131 has a constant height H, the switching transistor 31 and the heat-generating electronic devices between the switching transistor 31 and the terminal panel 126 are all cooled by at least one heat sink fin 124 of the same height, thereby making the heat dissipation area of ​​the at least one heat sink fin 124 more uniform, and thus improving the heat dissipation efficiency of the photovoltaic inverter 12 with the inverted circuit structure.

[0060] In one embodiment, the projection of the portion of each heat sink fin 124 with a constant height H coincides with the at least one switching transistor 31 and the at least one electronic device. Therefore, the switching transistor 31 and the electronic device dissipate heat through the heat sink fins 124 with relatively uniform size, so as to further improve the heat dissipation efficiency.

[0061] like Figure 7As shown, the power conversion circuit also includes a first power inductor 32, a second power inductor 33, and a bus capacitor 34. The at least one switching transistor 31 includes a first switching transistor 311 and a second switching transistor 312. The first power inductor 32, the first switching transistor 311, the bus capacitor 34, the second switching transistor 312, and the second power inductor 33 are arranged sequentially in the first receiving cavity 131 along a direction parallel to the plane of the terminal panel 126.

[0062] The first power inductor 32 is positioned opposite to the DC input terminal 127, and the second power inductor 33 is positioned opposite to the AC output terminal 128.

[0063] The aforementioned at least one heat dissipation fin 124 includes at least one first heat dissipation fin 141 and at least one second heat dissipation fin 142 arranged in parallel. The aforementioned at least one first heat dissipation fin 141 is arranged opposite to the first switching transistor 311, and the aforementioned at least one second heat dissipation fin 142 is arranged opposite to the second switching transistor 312. In this embodiment, the first switching transistor 311 can be a DC-side switching transistor, and the second switching transistor 312 can be an AC-side switching transistor. When the photovoltaic inverter 12 is working, the current enters from the DC input terminal 127, passes through the first power inductor 32, the first switching transistor 311, the bus capacitor 34, the second switching transistor 312, and the second power inductor 33, and flows out from the AC output terminal 128, thereby forming an approximately straight current path at least on one side inside the housing 123. This reduces the crossing of current paths, thereby reducing the impedance of the power conversion circuit.

[0064] Of course, it is understandable that the outer surface of the housing 123 may be provided with a plurality of third heat dissipation fins 143, which are distributed on both sides of the first heat dissipation fin 141 along the x direction and on both sides of the second heat dissipation fin 142 along the x direction.

[0065] Please continue reading. Figure 7The power conversion circuit also includes a DC-side common-mode inductor 35, an inverter capacitor 36, and an AC-side common-mode inductor 37. The DC-side common-mode inductor 35 is adjacent to the DC input terminal 127, and the AC-side common-mode inductor 37 is adjacent to the AC output terminal 128. A first power inductor 32 is located on the side of the DC-side common-mode inductor 35 away from the DC input terminal 127, a second power inductor 33 is located on the side of the AC-side inductor away from the AC output terminal 128, and the inverter capacitor 36 is located between the second power inductor 33 and the AC-side common-mode inductor 37. The DC-side common-mode inductor 35 is located within a first receiving cavity 131. The inverter capacitor 36 and the AC-side common-mode inductor 37 are located within a third receiving cavity 133. In this embodiment, by placing multiple electronic components of the power conversion circuit within separate receiving cavities, electromagnetic interference between components can be reduced, thereby improving the electromagnetic compatibility of the photovoltaic inverter 12, further reducing the losses of the photovoltaic inverter 12, and improving the operating efficiency of the photovoltaic inverter 12.

[0066] Figure 9 This is a schematic diagram of the current path of a photovoltaic inverter during operation, provided in an embodiment of this application. Figure 7 and Figure 9 As shown, when the photovoltaic inverter 12 is working, the current enters from the DC input terminal 127 and passes sequentially through the DC side common-mode inductor 35, the first power inductor 32, the first switch 311, the bus capacitor 34, the second switch 312, the second power inductor 33, the inverter capacitor 36, and the AC side common-mode inductor 37, and flows out from the AC output terminal 128. That is, the current flows sequentially along the second receiving cavity 132, the first receiving cavity 131, and the third receiving cavity 133, thereby forming an approximately U-shaped current path within the housing 123 (e.g., ...). Figure 9 (As shown by the dashed arrow in the middle), this reduces the crossing of current paths, thereby reducing the impedance of the power conversion circuit. Simultaneously, by placing the aforementioned multiple devices within separate housings, electromagnetic interference between devices can be reduced, thereby improving the electromagnetic compatibility of the photovoltaic inverter 12, and consequently reducing the losses and increasing the operating efficiency of the photovoltaic inverter 12.

[0067] In some embodiments, the AC output terminal 128 is a single-phase output terminal. The photovoltaic inverter 12 in this embodiment can be a single-phase photovoltaic inverter. Compared to a three-phase photovoltaic inverter, the power conversion circuit of a single-phase photovoltaic inverter has a simpler structure and can achieve less electromagnetic interference within the limited space of the housing 121.

[0068] like Figure 5 and Figure 6As shown, in some embodiments, the bottom wall of the housing 123 located within the first receiving cavity 131 is provided with a first boss 134 and a second boss 135, which extend from the housing 123 toward the circuit board 125. The first boss 134 separates the first power inductor 32 and the bus capacitor 34, and the second boss 135 separates the second power inductor 33 and the bus capacitor 34. A first switching transistor 311 is disposed on the surface of the first boss 134 opposite to the surface of the circuit board 125, and a second switching transistor 312 is disposed on the surface of the second boss 135 opposite to the surface of the circuit board 125. In this embodiment, when the bus capacitor 34 fails, the electrolyte inside the bus capacitor 34 may be ejected from the bus capacitor 34. The first boss 134 and the second boss 135 can separate the first power inductor 32 and the second power inductor 33 from the bus capacitor 34, thereby preventing electrolyte from entering the power inductor and damaging it.

[0069] like Figure 7 As shown, at least one first electronic device may be disposed in the first region between the first switching transistor 311 and the terminal panel 126, and at least one second electronic device may be disposed in the second region between the second switching transistor 312 and the terminal panel 126. Figure 10 for Figure 7 Cross-sectional view of the middle shell along the BB direction. Figure 11 for Figure 5 A top view of the shell along the z-direction. (e.g.) Figure 10 and Figure 11 As shown, the height of the aforementioned at least one first electronic device in the direction perpendicular to the circuit board 125 is less than or equal to the sum of the heights of the first switching transistor 311 and the first boss 134 in the direction perpendicular to the circuit board 125, and the height of the aforementioned at least one second electronic device in the direction perpendicular to the circuit board 125 is less than or equal to the sum of the heights of the second switching transistor 312 and the second boss 135 in the direction perpendicular to the circuit board 125, as shown. Figure 10 As shown, h1 is less than or equal to h2. Thus, on the outer surface of the housing 123 away from the cover 122, the portion of the outer surface adjacent to the first switch tube 311 and the at least one first electronic device is a flat surface, and the portion of the outer surface adjacent to the second switch tube 312 and the at least one second electronic device is a flat surface, so that the flowing air is not obstructed by the housing 123.

[0070] In one specific embodiment, the height h of each first electronic device can be less than or equal to 10 mm, and the height h of each second electronic device can be less than or equal to 10 mm.

[0071] like Figure 7As shown, a control device 39 and a sampling circuit 40 are also provided in the second receiving cavity 132. The control device 39 is used to control the power conversion circuit. In this embodiment, the control device 39 is located between the bus capacitor 34 and the terminal panel 126. Therefore, when the bus capacitor 34 fails and causes electrolyte leakage, since the circuit where the control device 39 is located is a low-voltage circuit, electrolyte leakage into the high-voltage circuit can be avoided, thus preventing damage to the power conversion circuit.

[0072] In some embodiments, a first thermal pad is disposed between the bottom wall of the housing 123 located in the second receiving cavity 132 and the bus capacitor 34. And / or, a second thermal pad is disposed between the bottom wall of the housing 123 located in the first receiving cavity 131 and the DC-side common-mode inductor 35. And / or, a third thermal pad is disposed between the bottom wall of the housing 123 located in the third receiving cavity 133 and the AC-side common-mode inductor 37. And / or, the power conversion circuit further includes a plurality of relays located within the first receiving cavity 131 and between the inverter capacitor 36 and the AC-side common-mode inductor 37, and a fourth thermal pad is disposed between the bottom wall of the housing 123 located in the first receiving cavity 131 and the plurality of relays. In this embodiment, the aforementioned thermal pads can accelerate heat exchange between the devices of the power conversion circuit and the housing 123, thereby improving the heat dissipation rate and heat dissipation effect.

[0073] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A photovoltaic inverter, characterized in that, The system includes a housing, a circuit board, and a power conversion circuit, wherein the circuit board and the power conversion circuit are located within the housing, wherein: The housing includes a cover and a shell, the cover fitting over the shell; the circuit board is located between the cover and the shell, and the plane of the circuit board is parallel to the surface of the shell opposite the cover; the shell or the cover includes a terminal panel, the terminal panel having DC input terminals and AC output terminals; the shell has multiple partitions extending from the shell toward the circuit board, dividing the space between the shell and the circuit board into multiple receiving cavities; the multiple receiving cavities include a first receiving cavity; The power conversion circuit includes at least one switching transistor; the at least one switching transistor is located within the first receiving cavity, and at least one electronic device is disposed between the at least one switching transistor and the terminal panel; at least one heat dissipation fin is disposed on the outer surface of the housing on the side away from the cover, the at least one heat dissipation fin is located opposite to the at least one switching transistor on both sides of the housing, and the at least one heat dissipation fin extends in a direction perpendicular to the terminal panel; the height of the at least one heat dissipation fin in the direction perpendicular to the outer surface is constant.

2. The photovoltaic inverter as described in claim 1, characterized in that, The projection of the portion of each heat sink fin with a constant height coincides with the at least one switching transistor and the at least one electronic device.

3. The photovoltaic inverter as described in claim 1 or 2, characterized in that, The power conversion circuit further includes a first power inductor, a second power inductor, and a bus capacitor. The at least one switching transistor includes a first switching transistor and a second switching transistor. The first power inductor, the first switching transistor, the bus capacitor, the second switching transistor, and the second power inductor are arranged sequentially in the first receiving cavity along a direction parallel to the plane of the terminal panel. The first power inductor is disposed opposite to the DC input terminal, and the second power inductor is disposed opposite to the AC output terminal. The at least one heat dissipation fin includes at least one first heat dissipation fin and at least one second heat dissipation fin arranged in parallel. The at least one first heat dissipation fin is disposed opposite to the first switching transistor, and the at least one second heat dissipation fin is disposed opposite to the second switching transistor.

4. The photovoltaic inverter as described in claim 3, characterized in that, The plurality of receiving cavities further includes a second receiving cavity and a third receiving cavity; the first receiving cavity, the second receiving cavity, and the third receiving cavity are respectively disposed adjacent to the terminal panel; a portion of the first receiving cavity is located between the second receiving cavity and the third receiving cavity, and another portion of the first receiving cavity is located on the side of the second receiving cavity and the third receiving cavity away from the terminal panel; The power conversion circuit further includes a DC-side common-mode inductor, an inverter capacitor, and an AC-side common-mode inductor; the DC-side common-mode inductor is located in the second receiving cavity and is adjacent to the DC input terminal, and the AC-side common-mode inductor is located in the third receiving cavity and is adjacent to the AC output terminal; the first power inductor is located on the side of the DC-side common-mode inductor away from the DC input terminal, the second power inductor is located on the side of the AC-side inductor away from the AC output terminal, and the inverter capacitor is located in the third receiving cavity and is located between the second power inductor and the AC-side common-mode inductor.

5. The photovoltaic inverter as described in claim 4, characterized in that, The AC output terminal is a single-phase output terminal.

6. The photovoltaic inverter as described in claim 4, characterized in that, The second accommodating cavity is also provided with a control device, which is used to control the power conversion circuit. The control device is located between the bus capacitor and the terminal panel.

7. The photovoltaic inverter as described in claim 4, characterized in that, A first thermal pad is provided between the bottom wall of the housing located in the second receiving cavity and the bus capacitor; and / or A second thermal pad is provided between the bottom wall of the housing located in the first receiving cavity and the DC-side common-mode inductor; and / or A third thermal pad is provided between the bottom wall of the housing located in the third receiving cavity and the AC side common mode inductor; and / or The power conversion circuit also includes multiple relays, which are located in the first receiving cavity between the inverter capacitor and the AC side common mode inductor. A fourth thermal pad is provided between the bottom wall of the housing located in the first receiving cavity and the multiple relays.

8. The photovoltaic inverter as described in claim 3, characterized in that, The bottom wall of the housing located within the first receiving cavity is provided with a first protrusion and a second protrusion, the first protrusion and the second protrusion extending from the housing toward the circuit board; the first protrusion separates the first power inductor and the bus capacitor, and the second protrusion separates the second power inductor and the bus capacitor; the first switching transistor is disposed on the surface of the first protrusion facing the circuit board, and the second switching transistor is disposed on the surface of the second protrusion facing the circuit board.

9. The photovoltaic inverter as described in claim 8, characterized in that, At least one first electronic device is disposed between the first switching transistor and the terminal panel, and the height of the at least one first electronic device in the direction perpendicular to the circuit board is less than or equal to the sum of the heights of the first switching transistor and the first boss in the direction perpendicular to the circuit board. At least one second electronic device is disposed between the second switching transistor and the terminal panel, wherein the height of the at least one second electronic device in the direction perpendicular to the circuit board is less than or equal to the sum of the heights of the second switching transistor and the second boss in the direction perpendicular to the circuit board.

10. The photovoltaic inverter as described in claim 9, characterized in that, The height of both the at least one first electronic device and the at least one second electronic device is less than or equal to 10 mm.

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