Photovoltaic inverter

Abstract

The invention provides a photovoltaic inverter. The photovoltaic inverter comprises a shell, a circuit board and a power conversion circuit, wherein the circuit board and the power conversion circuit are located in the shell. The shell comprises a first containing cavity, a second containing cavity, a third containing cavity and a fourth containing cavity. The power conversion circuit comprises a first inductor, a bus capacitor and a second inductor which are sequentially connected in series. The bus capacitor is located in the third accommodating cavity. The first inductor and the second inductor are located in the fourth containing cavity. A terminal panel of the housing is provided with a DC input terminal and an AC output terminal. The DC input terminal extends into the first accommodating cavity and is electrically connected with the first inductor, and the AC output terminal extends into the second accommodating cavity and is electrically connected with the second inductor. When the photovoltaic inverter works, current sequentially passes through the direct-current input terminal, the first inductor, the bus capacitor, the second inductor and the alternating-current output terminal, so that the current forms an approximate C-shaped flowing path in the shell, electromagnetic interference between modules is reduced, and the electromagnetic compatibility and the working efficiency of the photovoltaic inverter with the inverted buckling type structure are improved.

Description

Technical Field

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

[0002] Power converters can convert a certain type of current into another type of current and are widely used in power supply systems and power generation systems. The power converter includes a housing, a circuit board located in the housing, and a switch assembly and multiple power devices mounted on the circuit board.

[0003] Power converters need to meet the electromagnetic compatibility (EMC) standard before they can be put into use in the market. As the switching frequency of the power converter increases and the power output of the power converter increases, the electromagnetic susceptibility (EMS) of the power converter to other electronic devices becomes lower, and the electromagnetic signals generated by the power converter itself also cause greater electromagnetic interference to its internal components, that is, the electromagnetic interference (EMI) of the power converter is enhanced. Therefore, as the power of the power converter increases and the EMC requirements increase, how to improve the EMC of the power converter of the above structure and improve the working efficiency of the power converter has become a key research issue. Summary of the invention

[0004] The present application provides a photovoltaic inverter to improve the electromagnetic compatibility of a photovoltaic inverter with a flip-flop circuit structure.

[0005] In a first aspect, the present application provides a photovoltaic inverter. The photovoltaic inverter includes a housing, a circuit board and a power conversion circuit, and the circuit board and the power conversion circuit are accommodated in the housing. Specifically, the housing includes a bottom shell and a cover body, and the cover body is used to cover the bottom shell. A plurality of heat dissipation fins are provided on the surface of the bottom shell facing away from the cover body. The circuit board is arranged between the bottom shell and the cover body, and the plane where the circuit board is located is parallel to the surface of the cover body relative to the bottom shell. The bottom shell is provided with a plurality of partition plates, and the aforementioned plurality of partition plates extend from the bottom shell toward the circuit board, and divide the space between the bottom shell and the circuit board into a plurality of accommodating chambers. The aforementioned plurality of accommodating chambers include a first accommodating chamber, a second accommodating chamber, a third accommodating chamber and a fourth accommodating chamber. The bottom shell or the cover body includes a terminal panel, and the terminal panel includes a DC input terminal and an AC output terminal. The first accommodating chamber, the second accommodating chamber and the third accommodating chamber are all arranged adjacent to the terminal panel. The third accommodating chamber is located between the first accommodating chamber and the second accommodating chamber, the fourth accommodating chamber is located on the side of the third accommodating chamber away from the terminal panel, the third accommodating chamber is located between the fourth accommodating chamber and the first accommodating chamber, or the third accommodating chamber is located between the fourth accommodating chamber and the second accommodating chamber. The power conversion circuit includes a first inductor, a bus capacitor and a second inductor connected in series in sequence. The bus capacitor is located in the third accommodating cavity. The first inductor and the second inductor are located in the fourth accommodating cavity. The DC input terminal passes through the terminal panel, and one end of the DC input terminal extending into the first accommodating cavity is electrically connected to the first inductor, and the other end of the DC input terminal is used to be electrically connected to the photovoltaic module. The AC output terminal passes through the terminal panel, and one end of the AC output terminal extending into the second accommodating cavity is electrically connected to the second inductor, and the other end of the AC output terminal is used to be electrically connected to the power grid or the load. The power conversion circuit also includes a power module, which is located in the third accommodating cavity, and an insulating heat-conductive substrate is provided between the power module and the bottom wall of the third accommodating cavity.

[0006] In an embodiment of the present application, the photovoltaic inverter adopts an inverted structure to simplify the cable design of the power conversion circuit. Relative to the power conversion circuit being arranged in the housing in the forward direction (the first inductor, the bus capacitor and the second inductor are arranged between the circuit board and the cover), in the above-mentioned inverted structure, the distance between the heating device and the bottom shell is shorter, that is, the heat transfer distance required by the heating device is shorter, and the heat dissipation fins can directly transfer the heat generated by the heating device from the bottom shell to the heat dissipation fins, and dissipate heat through the heat dissipation fins, thereby facilitating the heat dissipation inside the photovoltaic inverter. When the photovoltaic inverter is working, the current enters from the DC input terminal and passes through the first inductor, the bus capacitor and the second inductor in sequence, and flows out from the AC output terminal, that is, the current flows along the first accommodating cavity, the third accommodating cavity, the fourth accommodating cavity, the third accommodating cavity, the fourth accommodating cavity, the third accommodating cavity and the second accommodating cavity in sequence, thereby forming a current path in the housing that is approximately C-shaped, which can reduce the intersection of the current path, thereby reducing the impedance of the power conversion circuit. At the same time, by placing the above-mentioned multiple devices in separate accommodating cavities, electromagnetic interference between devices can be reduced, thereby improving the electromagnetic compatibility of the photovoltaic inverter, thereby reducing the loss of the photovoltaic inverter and improving the working efficiency of the photovoltaic inverter.

[0007] Since the busbar capacitor is relatively large, in order to improve the space utilization of the shell, in a possible implementation, in the third accommodating cavity, a groove is provided on the surface of the bottom shell facing the cover body, and the busbar capacitor is partially accommodated in the groove. In this way, the surface shape of the bottom shell facing the cover body is the same as the surface shape of the power conversion circuit facing the bottom shell, so that the heat conduction path between the bottom shell and each module of the photovoltaic inverter can be more uniform, and the volume is smaller than that of a photovoltaic inverter with a flat bottom shell.

[0008] The above groove may be provided with an insulating film, and an explosion-proof valve is provided on the surface of the bus capacitor facing the insulating film. The explosion-proof valve is spaced a set distance from the insulating film. When the explosion-proof valve is opened, the valve cover of the explosion-proof valve pops up and abuts against the insulating film. The insulating film can insulate the bottom shell from the bus capacitor, preventing the bus capacitor from short-circuiting with other devices through the bottom shell when a fault occurs.

[0009] In addition, when a bus capacitor fails, the electrolyte inside the bus capacitor may spray out of the bus capacitor. In one possible implementation, the above-mentioned multiple partitions include a first partition, and the first accommodating chamber and the third accommodating chamber are isolated by the first partition. In the third accommodating chamber, a guide plate is provided on the side of the bottom shell facing the cover body, and the plane where the guide plate is located is perpendicular to the surface of the cover body relative to the bottom shell. The guide plate is located between the groove and the terminal panel, and one end of the guide plate is connected to the first partition plate, and the other end is inclined toward the terminal panel, so that the guide plate drains the electrolyte in the groove to prevent the electrolyte from flowing into other accommodating chambers and damaging other devices.

[0010] In one possible implementation, the power conversion circuit also includes a first communication circuit, which is accommodated in the third accommodating cavity and arranged near the terminal panel. The terminal panel also includes a first communication terminal, which passes through the terminal panel, and one end of the first communication terminal extending into the third accommodating cavity is electrically connected to the first communication circuit. The first communication terminal is used to transmit data in parallel to an external device. The other end of the guide plate is inclined toward the first communication terminal. In this technical solution, since the first communication circuit is a weak current circuit, the guide plate guides the electrolyte in the groove toward the first communication terminal, which can prevent the electrolyte from entering the strong current circuit and causing damage to the power conversion circuit.

[0011] In a possible implementation, the plurality of partitions may further include a second partition. The second partition divides the fourth accommodating chamber into a first cavity and a second cavity. The first cavity and the second cavity are respectively arranged adjacent to the third accommodating chamber. The first inductor is accommodated in the first cavity, and the second inductor is accommodated in the second cavity. In the fourth accommodating chamber, the second partition separates the first inductor and the second inductor, which can reduce interference between the first inductor and the second inductor. In addition, the second partition may also increase the heat dissipation area between the first inductor and the housing, and the heat dissipation area between the second inductor and the housing, thereby improving the heat dissipation efficiency of the first inductor and the second inductor.

[0012] In a possible implementation, the power module includes a first switch tube and a second switch tube. The first switch tube is electrically connected between a DC input terminal and a first inductor, and the second switch tube is electrically connected between a bus capacitor and a second inductor. The first switch tube is arranged close to the first inductor, and the second switch tube is arranged close to the second inductor. The first switch tube can be used to connect or disconnect the electrical connection between the first inductor and the DC input terminal, and the second switch tube can be used to connect or disconnect the electrical connection between the second inductor and the bus capacitor. By separating the switch tube from the inductor, the interference between the switch tube and the inductor can be reduced, and the heat dissipation area between the power module and the bottom shell can be increased.

[0013] In a possible implementation, the power conversion circuit further includes a plurality of relays, and the plurality of relays are located between the circuit board and the bottom shell. The plurality of partition plates include a third partition plate, and the second accommodating cavity and the third accommodating cavity are isolated by the third partition plate. A thermal pad is provided at one end of the third partition plate facing the cover body, and the thermal pad is used to contact the circuit board. The plurality of relays are distributed in two rows on both sides of the thermal pad. When the photovoltaic inverter is working, the relay and the area of ​​the circuit board close to the relay will generate heat. The thermal pad can be attached to the circuit board, so that the heat near the relay on the circuit board is transferred to the bottom shell through the thermal pad, further reducing the heating of the relay.

[0014] In a possible implementation, a metal bracket is further provided at one end of the third partition plate facing the cover body. A thermal pad is fixed to one end of the metal bracket facing the cover body, and the plurality of relays are arranged in two rows on both sides of the metal bracket, so that the metal bracket can be used to accommodate the relays and transfer the heat of the thermal pad to the bottom shell.

[0015] In a possible implementation, the above-mentioned multiple accommodating chambers also include a fifth accommodating chamber, which is arranged adjacent to the terminal panel, and the fifth accommodating chamber is located between the third accommodating chamber and the second accommodating chamber. The power conversion circuit also includes a second communication circuit. The second communication circuit is accommodated in the fifth accommodating chamber and is used to send and receive interactive data. The terminal panel also includes a second communication terminal. The second communication terminal runs through the terminal panel, and one end of the second communication terminal extending into the fifth accommodating chamber is electrically connected to the second communication circuit. The second communication terminal is used to transmit data serially to an external device. In this technical solution, the second communication terminal is arranged on the same side as the DC input terminal and the AC output terminal, so that the wiring of the photovoltaic inverter can be arranged on the same side to facilitate the installation of the photovoltaic inverter.

[0016] In a possible implementation, the photovoltaic inverter further includes a switch, which is disposed in the housing and connected between the DC input terminal and the first inductor. The switch is used to conduct or disconnect the electrical connection between the photovoltaic assembly and the power conversion circuit, so that the output DC power of the photovoltaic assembly and the DC input circuit of the photovoltaic inverter can be disconnected when a fault occurs, so as to protect the photovoltaic inverter.

[0017] In a possible implementation, a chip resistor, a chip capacitor and a signal indicator light are also provided on the side of the circuit board facing the cover. The signal indicator light is used to indicate the working status of the photovoltaic inverter. In the inverted structure, the height of the space between the circuit board and the cover is small, and a small device can be set to make full use of the space in the shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of an application scenario of a photovoltaic system provided in an embodiment of the present application;

[0019] Figure 2 A front schematic diagram of a photovoltaic inverter provided in an embodiment of the present application;

[0020] Figure 3 A schematic diagram of the back side of a photovoltaic inverter provided in an embodiment of the present application;

[0021] Figure 4 An exploded schematic diagram of a photovoltaic inverter provided in an embodiment of the present application;

[0022] Figure 5 A schematic diagram of a bottom case provided in an embodiment of the present application;

[0023] Figure 6 A schematic diagram of a power conversion circuit and a bottom case provided in an embodiment of the present application;

[0024] Figure 7 A schematic diagram of the current path of the photovoltaic inverter provided in an embodiment of the present application when in operation;

[0025] Figure 8 A schematic diagram of a power conversion circuit provided in an embodiment of the present application;

[0026] Fig. 9 Another schematic diagram of the bottom shell provided in the embodiment of the present application;

[0027] Fig.10 Another schematic diagram of a power conversion circuit and a bottom case provided in an embodiment of the present application;

[0028] Fig.11 Another schematic diagram of the bottom shell provided in the embodiment of the present application;

[0029] Fig.12 for Fig.11 A schematic cross-sectional view of the mid-bottom shell along the AA direction;

[0030] Fig.13 The photovoltaic inverter provided in the embodiment of the present application is Fig.11 Schematic diagram of the cross section along the AA direction;

[0031] Fig.14 Another schematic diagram of the bottom shell provided in the embodiment of the present application;

[0032] Fig.15 for Fig.14 Cross-sectional view of the midsole shell along the BB direction;

[0033] Fig.16 A schematic diagram of a power conversion circuit and a bottom case provided in an embodiment of the present application;

[0034] Fig.17 Another schematic diagram of the bottom shell provided in the embodiment of the present application;

[0035] Fig.18 Another schematic diagram of a power conversion circuit provided in an embodiment of the present application;

[0036] Fig.19 Another schematic diagram of the bottom shell provided in the embodiment of the present application;

[0037] Fig. 20 A schematic diagram of a thermal pad and a metal bracket provided in an embodiment of the present application;

[0038] Fig.21 Another schematic diagram of the bottom shell provided in an embodiment of the present application.

[0039] Reference numerals:

[0040] 10- Photovoltaic system

[0041] 11- Photovoltaic panels

[0042] 12-Photovoltaic inverter

[0043] 13-Energy storage equipment

[0044] 20-Power grid

[0045] 31-First accommodating chamber

[0046] 32- Second accommodating chamber

[0047] 33- The third accommodating chamber

[0048] 34-Fourth accommodating chamber

[0049] 35-Fifth accommodating chamber

[0050] 121-Shell

[0051] 122-Power conversion circuit

[0052] 123-Switch

[0053] 331-Groove

[0054] 332-Deflector

[0055] 333-Insulation film

[0056] 334-Thermal pad

[0057] 335-Metal Bracket

[0058] 336-first insulating thermal conductive substrate

[0059] 337-Second insulating thermal conductive substrate

[0060] 341-Second partition

[0061] 342-First cavity

[0062] 343-Second cavity

[0063] 1210-Terminal Panel

[0064] 1211-cover

[0065] 1212- bottom shell

[0066] 1213-DC input terminal

[0067] 1214-AC output terminal

[0068] 1215-Separator

[0069] 1216-Heat radiator

[0070] 1217-First communication terminal

[0071] 1218 second communication terminal

[0072] 1221-DC input circuit

[0073] 1222-DC conversion circuit

[0074] 1223-Bus capacitor

[0075] 1224-Inverter Circuit

[0076] 1225-AC output circuit

[0077] 1226-Circuit Board

[0078] 1227-Filter circuit

[0079] 1228-First communication circuit

[0080] 1229-Second communication circuit

[0081] 12151-First separator

[0082] 12152-Third partition

[0083] 12221-First Inductor

[0084] 12222-First switch tube

[0085] 12241-Second inductor

[0086] 12242-Second switch tube

[0087] 12271-Relay

[0088] 12261-chip resistor

[0089] 12262-chip capacitor

[0090] 12263-Signal indicator light DETAILED DESCRIPTION

[0091] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0092] In order to facilitate the understanding of the photovoltaic inverter provided in the embodiment of the present application, its application scenario is described below. The photovoltaic inverter of the present application can be applied to power supply systems and power generation systems. Taking the photovoltaic system as an example, the photovoltaic system can be used in two application scenarios: home power stations and industrial photovoltaic power stations. The photovoltaic inverter can convert solar energy into electrical energy to supply the power grid or load. Figure 1 A schematic diagram of an application scenario of a photovoltaic system provided in an embodiment of the present application. Figure 1 As shown, the photovoltaic system 10 is applied to a household power station. Specifically, the photovoltaic module 11 is used to convert light energy into electrical energy. The photovoltaic system 10 includes a photovoltaic inverter 12, one end of which is used to connect to the photovoltaic module 11, and the other end is used to connect to the power grid 20. The photovoltaic inverter 12 is used to convert the direct current from the photovoltaic module 11 into alternating current, and transmit the alternating current to the power grid 20. A photovoltaic optimizer can also be installed in the photovoltaic system 10, and the photovoltaic optimizer can be used to improve the power generation efficiency of the photovoltaic module 11. Among them, the photovoltaic optimizer is a component-level power electronic device with direct current input and direct current output. By connecting in series with the photovoltaic module 11, the predicted current and voltage technology is adopted to ensure that the component is always in the optimal working state. According to the working principle of the buck topology, it is used to solve the influence of shadow shading, inconsistent orientation or difference in electrical specifications of the components on the power generation of the photovoltaic power station, and realize the maximum power output of the photovoltaic module 11, thereby improving the power generation of the photovoltaic system 10. Of course, the photovoltaic system 10 can 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.

[0093] In addition, an on-grid and off-grid controller may be provided between the photovoltaic inverter 12 and the power grid 20. The photovoltaic inverter 12 may convert the direct current provided by the photovoltaic module 11 into alternating current, and transmit the alternating current to the on-grid and off-grid controller. The on-grid and off-grid controller may also be electrically connected to the power-consuming device. In actual application scenarios, the on-grid and off-grid controller has an off-grid state and a on-grid state. When the on-grid and off-grid controller is in the off-grid state, there is no electrical connection between the on-grid and off-grid controller and the power grid 20, and the alternating current transmitted by the photovoltaic inverter 12 is only provided to the power-consuming device. Among them, the power-consuming device includes household appliances, such as televisions, air conditioners, refrigerators, washing machines, etc.

[0094] When the on-grid and off-grid controller is in the on-grid state, the on-grid and off-grid controller is electrically connected to the grid 20 through the power sensor. When the electric energy generated by the photovoltaic module 11 cannot meet the power demand of the electric equipment, the grid 20 can provide electric energy to the photovoltaic system 10 through the on-grid and off-grid controller. When the power generation of the photovoltaic module 11 exceeds the power used by the electric equipment, the on-grid and off-grid controller can transmit the excess power to the grid 20. Among them, 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 electric meter.

[0095] As the loss and efficiency requirements of photovoltaic systems increase, the electromagnetic compatibility requirements of photovoltaic inverters are also gradually increasing. Therefore, how to improve the electromagnetic compatibility of photovoltaic inverters has gradually become an important research issue.

[0096] In view of this, the present application provides a photovoltaic inverter to improve the electromagnetic compatibility of a photovoltaic inverter with a flip-flop circuit structure.

[0097] It should be noted that the terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to be limiting of the present application. As used in the specification and appended claims of the present application, the singular expressions "a", "an", "said", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear indication to the contrary in the context.

[0098] References to "one embodiment" or "some embodiments" etc. described in this specification mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear at different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0099] In this application, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0100] In addition, in this article, directional terms such as "top", "bottom", "upper" and "lower" are defined relative to the orientation of the structure schematically placed in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they can change accordingly according to the change of the orientation of the structure.

[0101] Figure 2 This is a front view of a photovoltaic inverter provided in an embodiment of the present application. Figure 3 This is a schematic diagram of the back side of the photovoltaic inverter provided in the embodiment of the present application. Figure 4 This is an exploded schematic diagram of a photovoltaic inverter provided in an embodiment of the present application. Figures 2 to 4 As shown, the photovoltaic inverter 12 includes a housing 121 and a power conversion circuit 122. The housing 121 includes a cover 1211 and a bottom housing 1212. The cover 1211 is used to cover the bottom housing 1212 and form an internal space for accommodating the power conversion circuit 122. In actual application, the side surface (i.e., the back side) of the bottom housing 1212 facing away from the cover 1211 is hung on the mounting plate, and the cover 1211 (i.e., the front side) faces the user.

[0102] It should be noted that, in some embodiments, the bottom shell 1212 may be a basin-shaped structure, that is, the bottom shell 1212 includes a bottom shell bottom plate and a plurality of bottom shell side plates, which are sequentially connected and arranged vertically with the bottom shell bottom plate. In this embodiment, the cover 1211 may be a plate-shaped structure, and is arranged opposite to the bottom shell bottom plate, and the periphery of the cover 1211 is connected to the above-mentioned plurality of bottom shell side plates, thereby forming a space that can accommodate the power conversion circuit 122. Of course, in this embodiment, the cover 1211 may also be a basin-shaped structure, that is, the cover 1211 includes a cover bottom plate and a plurality of cover side plates, which are sequentially connected and arranged vertically with the cover bottom plate. The cover bottom plate is arranged opposite to the bottom shell bottom plate, and the above-mentioned plurality of cover side plates are connected to the above-mentioned plurality of bottom shell side plates, thereby forming a space that can accommodate the power conversion circuit 122. In other embodiments, the cover 1211 may be a basin-shaped structure. The bottom shell 1212 may be a plate-shaped structure, and is arranged opposite to the cover bottom plate. The bottom shell 1212 is connected to the plurality of cover side panels to form a space for accommodating the power conversion circuit 122 .

[0103] The structure of the photovoltaic inverter 12 is described in detail below by taking as an example a housing 121 in which the bottom shell 1212 may be a basin-shaped structure and the cover body 1211 may be a plate-shaped structure.

[0104] The photovoltaic inverter of the present application adopts an inverted structure to simplify the cable design of the power conversion circuit and realize centralized heat dissipation of the heating device. Figure 4 As shown, the photovoltaic inverter 12 further includes a circuit board 1226. The plane where the circuit board 1226 is located is parallel to the surface of the cover 1211 relative to the bottom shell 1212. Specifically, the front side of the circuit board 1226 is arranged toward the cover 1211, and the switch assembly and multiple power devices of the power conversion circuit 122 are located on the back side of the circuit board 1226 and are arranged toward the bottom plate of the bottom shell 1212. In this way, the switch assembly and multiple power devices can be connected to the circuit board 1226 through pins to achieve a rigid connection with the circuit board 1226, thereby simplifying the cable design.

[0105] like Figure 3As shown, in the housing 121 of the present application, a plurality of heat dissipation fins 1216 are provided on the surface of the side of the bottom housing 1212 facing away from the cover 1211. Compared with the arrangement of the power conversion circuit 122 in the housing 121 in the forward direction (i.e., the arrangement of the first inductor 12221, the bus capacitor 1223 and the second inductor 12241 on the side of the circuit board 1226 facing the cover 1211), in the above embodiment, the inverted structure can make the distance between the heating device and the bottom housing 1212 shorter, i.e., the heat transfer distance required by the heating device is shorter, and the heat dissipation fins 1216 can directly transfer the heat generated by the heating device from the bottom housing 1212 to the heat dissipation fins 1216, and dissipate the heat through the heat dissipation fins 1216, thereby facilitating the heat dissipation inside the photovoltaic inverter 12.

[0106] Figure 5 A schematic diagram of the bottom shell provided in the embodiment of the present application. Figure 5 As shown, the bottom shell 1212 is provided with a plurality of partition plates 1215, which extend from the bottom shell 1212 toward the circuit board 1226 and divide the space between the bottom shell 1212 and the circuit board 1226 into a plurality of accommodating chambers, which are separated from each other. The plurality of accommodating chambers include a first accommodating chamber 31, a second accommodating chamber 32, a third accommodating chamber 33, and a fourth accommodating chamber 34. The housing 121 includes a terminal panel 1210, which may be a part of the bottom shell 1212 or a part of the cover 1211. Figure 2 and Figure 3 As shown, the terminal panel 1210 is a bottom shell side plate of the bottom shell 1212. The terminal panel 1210 includes a DC input terminal 1213 and an AC output terminal 1214. In this embodiment, the first accommodating cavity 31, the second accommodating cavity 32, and the third accommodating cavity 33 are all arranged adjacent to the terminal panel 1210. In other words, the terminal panel 1210 can form the side walls of the first accommodating cavity 31, the second accommodating cavity 32, and the third accommodating cavity 33. The third accommodating cavity 33 is located between the first accommodating cavity 31 and the second accommodating cavity 32, the fourth accommodating cavity 34 is located on the side of the third accommodating cavity 33 away from the terminal panel 1210, the third accommodating cavity 33 is located between the fourth accommodating cavity 34 and the first accommodating cavity 31, or the third accommodating cavity 33 is located between the fourth accommodating cavity 34 and the second accommodating cavity 32.

[0107] Figure 6 A schematic diagram of a power conversion circuit and a bottom case provided in an embodiment of the present application, Figure 7 This is a schematic diagram of the current path of the photovoltaic inverter provided in the embodiment of the present application when it is working. Figure 6 and Figure 7As shown, in the embodiment of the present application, the power conversion circuit 122 includes a first inductor 12221, a bus capacitor 1223 and a second inductor 12241 connected in series in sequence. The bus capacitor 1223 is located in the third accommodating cavity 33. The first inductor 12221 and the second inductor 12241 are located in the fourth accommodating cavity 34. The DC input terminal 1213 passes through the terminal panel 1210, and one end of the DC input terminal 1213 extending into the first accommodating cavity 31 is electrically connected to the first inductor 12221, and the other end of the DC input terminal 1213 is electrically connected to the photovoltaic module 11. The AC output terminal 1214 passes through the terminal panel 1210, and one end of the AC output terminal 1214 extending into the second accommodating cavity 32 is electrically connected to the second inductor 12241, and the other end of the AC output terminal 1214 is electrically connected to the power grid 20 or the load.

[0108] When the photovoltaic inverter 12 is working, the current passes through the DC input terminal 1213, the first inductor 12221, the bus capacitor 1223, the second inductor 12241 and the AC output terminal 1214 in sequence, so that the current flows along the first accommodating cavity 31, the third accommodating cavity 33, the fourth accommodating cavity 34, the third accommodating cavity 33, the fourth accommodating cavity 34, the third accommodating cavity 33 and the second accommodating cavity 32 in sequence, and forms an approximately C-shaped current path in the shell 121, so that the intersection of the current path can be reduced, thereby reducing the impedance of the power conversion circuit 122. At the same time, the above-mentioned multiple devices can be placed in different separated accommodating cavities to reduce electromagnetic interference between the devices, thereby improving the electromagnetic compatibility of the photovoltaic inverter 12, thereby reducing the loss of the photovoltaic inverter 12 and improving the working efficiency of the photovoltaic inverter 12, thereby reducing the loss of the photovoltaic system 10 and improving the working efficiency.

[0109] Figure 8 A schematic diagram of a power conversion circuit provided in an embodiment of the present application. Figure 8As shown, in the photovoltaic inverter 12, the power conversion circuit 122 includes a DC conversion circuit 1222, a bus capacitor 1223 and an inverter circuit 1224. Among them, the DC conversion circuit 1222 includes a first inductor 12221, and the inverter circuit 1224 includes a second inductor 12241. Further, the power conversion circuit 122 also includes a filter circuit 1227 and a relay 12271. The filter circuit 1227 is connected between the inverter circuit 1224 and the AC output terminal 1214, and the relay 12271 is connected between the filter circuit 1227 and the AC output terminal 1214. The relay 12271 can be used as an output protection switch to ensure the stability of the output current. In addition, the power conversion circuit 122 can also include a DC input circuit 1221 and an AC output circuit 1225. The DC input circuit 1221 is connected between the DC input terminal 1213 and the DC conversion circuit 1222. The DC input circuit 1221 is accommodated in the first accommodation cavity 31 and is connected to the DC input terminal 1213. The AC output circuit 1225 is connected between the relay 12271 and the AC output terminal 1214 and is accommodated in the second accommodation cavity 32.

[0110] In addition, the power conversion circuit 122 also includes a power module, and the power module is located in the third accommodating chamber 33. An insulating heat-conducting substrate is provided between the power module and the bottom wall of the third accommodating chamber 33. The power module is connected to the bottom shell 1212 by heat conduction through the insulating heat-conducting substrate, which can accelerate the heat dissipation efficiency of the power module. And when the bus capacitor 1223 fails, the insulating heat-conducting substrate can prevent the bottom shell 1212 from being short-circuited with the power module when the bus capacitor 1223 is short-circuited with the bottom shell 1212.

[0111] Fig. 9 Another schematic diagram of the bottom shell provided in the embodiment of the present application. Fig. 9 As shown, the photovoltaic inverter 12 further includes a switch 123, which is connected to the DC input circuit 1221 and is used to connect or disconnect the DC input circuit 1221. In this way, when a fault occurs in the photovoltaic system 10, the switch 123 can disconnect the electrical connection between the photovoltaic module 11 and the DC input circuit 1221, thereby disconnecting the DC input circuit 1221 from the DC output of the photovoltaic module 11 to protect the photovoltaic inverter 12.

[0112] In the above-mentioned inverted structure, the height of the space between the circuit board 1226 and the cover body 1211 is relatively small, and components with relatively small volumes can be arranged to fully utilize the space in the housing 121 . Fig.10 Another schematic diagram of the power conversion circuit and the bottom shell provided in the embodiment of the present application. Fig.10As shown, in one embodiment, a chip resistor 12261, a chip capacitor 12262 and a signal indicator light 12263 are also provided on one side of the circuit board 1226 facing the cover body 1211. Among them, the chip resistor 12261 can be used to limit the current in the circuit, resist the interference and noise of the circuit, etc., and the chip capacitor 12262 can be used to store charge. The signal indicator light 12263 is used to indicate the working state of the photovoltaic inverter 12, such as normal working, standby, communication connection and other states. In this embodiment, the number of signal indicator lights 12263 is not limited. For example, in one embodiment, a signal indicator light 12263 can be set, and the signal indicator light 12263 displays different colors to indicate the state of the photovoltaic inverter 12. Alternatively, in another embodiment, multiple signal indicator lights 12263 can also be set, each signal indicator light 12263 displays a color, and the colors of the multiple signal indicator lights 12263 are different. In this way, each signal indicator light 12263 can fixedly indicate a state of the photovoltaic inverter 12.

[0113] Fig.11 Another schematic diagram of the bottom shell provided in the embodiment of the present application, Fig.12 for Figure 1 Schematic diagram of the cross section of the midsole shell along the AA direction. Fig.13 The photovoltaic inverter provided in the embodiment of the present application is Fig.11 Schematic diagram of the cross section along the AA direction. Fig.11 , Fig.12 and Fig.13 As shown, due to the large volume of the bus capacitor 1223, in order to improve the space utilization rate in the housing 121, in one embodiment, in the third accommodating cavity 33, a groove 331 is provided on the surface of the bottom shell 1212 facing the cover 1211, and the bus capacitor 1223 is partially accommodated in the groove 331. In this way, the surface shape of the bottom shell 1212 facing the cover 1211 is the same as the surface shape of the power conversion circuit 122 facing the bottom shell 1212, that is, the surface shape of the bottom shell 1212 facing the cover 1211 can be designed in accordance with the position of the circuit device on the circuit board 1226, so that the gap between the bottom shell 1212 and each module of the power conversion circuit 122 can be more uniform, and the volume is smaller than that of the photovoltaic inverter with a flat bottom shell. In addition, this structural design can also reduce the volume of the photovoltaic inverter 12 and increase the heat dissipation area of ​​the circuit device.

[0114] In addition, when the bus capacitor 1223 fails, the electrolyte inside the bus capacitor 1223 may spray out from the bus capacitor 1223. Fig.14 Another schematic diagram of the bottom shell provided in the embodiment of the present application, Fig.15 for Fig.14 The cross-sectional view of the midsole shell along the BB direction. Fig.14and Fig.15 As shown, in one embodiment, the plurality of partition plates 1215 include a first partition plate 12151, and the first accommodating cavity 31 and the third accommodating cavity 33 are separated by the first partition plate 12151, that is, the first accommodating cavity 31 and the third accommodating cavity 33 are located on both sides of the first partition plate 12151. In the third accommodating cavity 33, a guide plate 332 may be provided on one side surface of the bottom shell 1212 facing the cover body 1211, and the plane where the guide plate 332 is located is perpendicular to the surface of the cover body 1211 relative to the bottom shell 1212. The guide plate 332 is located between the groove 331 and the terminal panel 1210. One end of the guide plate 332 is connected to the first partition plate 12151, and the other end extends toward the second side of the housing 122. In actual applications, the first partition plate 12151 and the circuit board 1226 cannot be completely fitted. Therefore, in the absence of the guide plate 332, the electrolyte in the groove 331 flows to the first partition plate 12151 under the action of gravity, and flows into the first accommodating chamber 31 from the gap between the first partition plate 12151 and the circuit board 1226. Since the DC input circuit 1221 in the first accommodating chamber 31 is a high-voltage device, the electrolyte flowing into the first accommodating chamber 31 will cause a short circuit in the high-voltage circuit, which poses a great safety risk. Fig.14 As shown, the guide plate 332 guides the electrolyte in the groove 331 to a side position of the third accommodating chamber 33 close to the second side, which can prevent the electrolyte from entering the first accommodating chamber 31 and damaging the electronic components of the DC input circuit 1221.

[0115] like Fig.13 As shown, the groove 331 may be provided with an insulating film 333. An explosion-proof valve is provided on the surface of the bus capacitor 1223 facing the insulating film 333. The explosion-proof valve is spaced a set distance from the insulating film 333. When the explosion-proof valve is opened, the valve cover of the explosion-proof valve pops up and abuts against the insulating film 333. The insulating film 333 can insulate the bottom shell 1212 from the bus capacitor 1223, thereby preventing the bus capacitor 1223 from short-circuiting with other devices through the bottom shell 1212 when a fault occurs.

[0116] Fig.16 A schematic diagram of a power conversion circuit and a bottom shell provided in an embodiment of the present application. Figure 2 and Fig.16As shown, in one embodiment, the terminal panel 1210 further includes a first communication terminal 1217. The power conversion circuit 122 further includes a first communication circuit 1228, which is accommodated in the third accommodation cavity 33. The first communication terminal 1217 penetrates the terminal panel 1210, and one end of the first communication terminal 1217 extending into the third accommodation cavity 33 is electrically connected to the first communication circuit 1228. In this embodiment, the first communication terminal 1217 is used to transmit data to an external device in parallel, and can send and receive parameter data of the photovoltaic inverter 12. For example, the first communication terminal 1217 can be connected to an external device through a wireless connection method such as 4G, FE (fast ethernet), etc. In this embodiment, the other end of the guide plate 332 is inclined toward the first communication terminal 1217. Since the first communication circuit 1228 is a weak current circuit, the guide plate 332 guides the electrolyte in the groove 331 toward the first communication terminal 1217, which can prevent the electrolyte from entering the strong current circuit and causing damage to the power conversion circuit 122.

[0117] Fig.17 A schematic diagram of a power conversion circuit and a bottom case provided in an embodiment of the present application, Fig.18 Another schematic diagram of the bottom shell provided in the embodiment of the present application. Fig.17 and Fig.18 As shown, in one embodiment, the power module includes a first switch tube 12222 and a second switch tube 12242. The first switch tube 12222 is electrically connected between the DC input terminal 1213 and the first inductor 12221, and the second switch tube 12242 is electrically connected between the bus capacitor 1223 and the second inductor 12241. The first switch tube 12222 and the second switch tube 12242 are located in the third accommodating cavity 33, the first switch tube 12222 is arranged close to the first inductor 12221, and the second switch tube 12242 is arranged close to the second inductor 12241. By separating the switch tube from the inductor, the interference between the switch tube and the inductor can be reduced, and the heat dissipation area of ​​the DC conversion circuit 1222 and the inverter circuit 1224 can be increased respectively.

[0118] In the photovoltaic inverter 12, the third accommodating cavity 33 is provided with a first insulating heat conductive substrate 336 and a second insulating heat conductive substrate 337. The surface of the first switch tube 12222 facing the bottom shell 1212 is attached to the first insulating heat conductive substrate 336, and the surface of the second switch tube 12242 facing the bottom shell 1212 is attached to the second insulating heat conductive substrate 337. The first switch tube 12222 is thermally connected to the bottom shell 1212 through the first insulating heat conductive substrate 336, and the second switch tube 12242 is thermally connected to the bottom shell 1212 through the second insulating heat conductive substrate 337, which can accelerate the heat dissipation efficiency of the first switch tube 12222 and the second switch tube 12242. In addition, the first switch tube 12222, the second switch tube 12242 and the bus capacitor 1223 are located in the same accommodating cavity, and the first insulating thermally conductive substrate 336 and the second insulating thermally conductive substrate 337 can reduce the impact of the bus capacitor 1223 on the first switch tube 12222 and the second switch tube 12242 when a fault occurs in the bus capacitor 1223.

[0119] like Figure 4 As shown, in one embodiment, a second partition plate 341 is provided in the fourth accommodation cavity 34, and the second partition plate 341 divides the fourth accommodation cavity 34 into a first cavity 342 and a second cavity 343. The first cavity 342 and the second cavity 343 are respectively arranged adjacent to the third accommodation cavity 33. The first inductor 12221 is accommodated in the first cavity 342, and the second inductor 12241 is accommodated in the second cavity 343. In the fourth accommodation cavity 34, the second partition plate 341 separates the first inductor 12221 and the second inductor 12241, which can reduce the interference between the first inductor 12241 and the second inductor 12241. In addition, the second partition plate 341 increases the heat dissipation area between the first inductor 12221 and the housing 121, and the heat dissipation area between the second inductor 12241 and the housing 121, thereby improving the heat dissipation efficiency of the first inductor 12241 and the second inductor 12241.

[0120] In one embodiment, the power conversion circuit 122 further includes a plurality of relays. The plurality of relays are located on a side of the circuit board 1226 away from the cover 1211 . Fig.19 Another schematic diagram of a power conversion circuit provided in an embodiment of the present application. Fig.19As shown, the plurality of partition plates 1215 also include a third partition plate 12152, and the third accommodating chamber 33 and the second accommodating chamber 32 are separated by the third partition plate 12152, that is, the third accommodating chamber 33 and the second accommodating chamber 32 are located on both sides of the third partition plate 12152. A thermal pad 334 is provided on the side of the third partition plate 12152 facing the cover body 1211, and the thermal pad 334 is used to contact the circuit board 1226. The plurality of relays are distributed in two rows on both sides of the thermal pad 334. When the photovoltaic inverter 12 is working, the relay and the area of ​​the circuit board 1226 near the relay will generate heat. The thermal pad 334 can be used to fit the circuit board 1226 of the power conversion circuit 122, so that the heat near the relay on the circuit board 1226 can be transferred from the thermal pad 334 to the bottom shell 1212, so as to reduce the heating of the relay and avoid the relay from overheating and malfunctioning.

[0121] In the present application, a pin is provided on one side of the relay facing the circuit board 1226, and the pin is fixed to the circuit board 1226 and connected to the metal trace. The above-mentioned multiple relays are distributed on the periphery of the thermal pad 334, so that the distance between the area of ​​the circuit board 1226 close to the relay and the thermal pad 334 is shorter. Fig. 20 Schematic diagram of the thermal pad and metal bracket provided in the embodiment of the present application. Fig.19 and Fig. 20 As shown, in one embodiment, a metal bracket 335 is further provided on the side of the third partition plate 12152 facing the cover 1211. The thermal pad 334 is fixed to the side of the metal bracket 335 facing the cover 1211, and the plurality of relays are arranged in two rows on both sides of the metal bracket 335, so that the metal bracket 335 can be used to accommodate the relays and transfer the heat of the thermal pad 334 to the bottom case 1212.

[0122] Fig.21 Another schematic diagram of the bottom shell provided in the embodiment of the present application. Figure 2 , Figure 3 and Fig.21As shown, in one embodiment, the terminal panel 1210 further includes a second communication terminal 1218. The plurality of accommodating chambers further include a fifth accommodating chamber 35, which is disposed adjacent to the terminal panel 1210, and the fifth accommodating chamber 35 is located between the second accommodating chamber 32 and the third accommodating chamber 33. The power conversion circuit 122 further includes a second communication circuit, which is contained in the fifth accommodating chamber 35. The second communication terminal 1218 penetrates the terminal panel 1210, and one end of the second communication terminal 1218 extending into the fifth accommodating chamber 35 is electrically connected to the second communication circuit. The second communication terminal 1218 is used to transmit data serially to an external device, for example, the second communication terminal 1218 can be connected to an external device through a communication cable. In this embodiment, the second communication terminal 1218 is disposed on the same side as the DC input terminal 1213 and the AC output terminal 1214, so that the wiring of the photovoltaic inverter 12 can be disposed on the same side to facilitate the installation of the photovoltaic inverter 12.

[0123] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A photovoltaic inverter, characterized in that: It comprises a housing, a circuit board and a power conversion circuit, wherein the circuit board and the power conversion circuit are accommodated in the housing, wherein: The housing comprises a bottom shell and a cover body, wherein the cover body is used to cover the bottom shell; a surface of the bottom shell facing away from the cover body is provided with a plurality of heat dissipation fins; the circuit board is arranged between the bottom shell and the cover body, and the plane where the circuit board is located is parallel to the surface of the cover body relative to the bottom shell; the bottom shell is provided with a plurality of partition plates, which extend from the bottom shell toward the circuit board and divide the space between the bottom shell and the circuit board into a plurality of accommodating cavities; The plurality of accommodating chambers include a first accommodating chamber, a second accommodating chamber, a third accommodating chamber and a fourth accommodating chamber; the bottom shell or the cover body includes a terminal panel, the terminal panel includes a DC input terminal and an AC output terminal, the first accommodating chamber, the second accommodating chamber and the third accommodating chamber are all arranged adjacent to the terminal panel, the third accommodating chamber is located between the first accommodating chamber and the second accommodating chamber, the fourth accommodating chamber is located on a side of the third accommodating chamber away from the terminal panel, the third accommodating chamber is located between the fourth accommodating chamber and the first accommodating chamber, or the third accommodating chamber is located between the fourth accommodating chamber and the second accommodating chamber; The power conversion circuit comprises a first inductor, a bus capacitor and a second inductor which are sequentially connected in series; the bus capacitor is located in the third accommodating cavity, and the first inductor and the second inductor are located in the fourth accommodating cavity; the DC input terminal passes through the terminal panel, one end of the DC input terminal extending into the first accommodating cavity is electrically connected to the first inductor, and the other end of the DC input terminal is used to be electrically connected to the photovoltaic module; the AC output terminal passes through the terminal panel, one end of the AC output terminal extending into the second accommodating cavity is electrically connected to the second inductor, and the other end of the AC output terminal is used to be electrically connected to the power grid or the load; The power conversion circuit further comprises a power module, wherein the power module is located in the third accommodating cavity, and an insulating heat-conducting substrate is provided between the power module and the bottom wall of the third accommodating cavity.

2. The photovoltaic inverter according to claim 1, characterized in that: In the third accommodating cavity, a groove is provided on a surface of the bottom shell facing the cover body, and the busbar capacitor is partially accommodated in the groove.

3. The photovoltaic inverter according to claim 2, characterized in that: An insulating film is arranged in the groove, an explosion-proof valve is arranged on a surface of the bus capacitor facing the insulating film, and the explosion-proof valve is spaced a set distance from the insulating film.

4. The photovoltaic inverter according to any one of claims 1 to 3, characterized in that: The plurality of partition plates include a first partition plate, and the first accommodating chamber and the third accommodating chamber are separated by the first partition plate; In the third accommodating cavity, a guide plate is provided on the side of the bottom shell facing the cover body, and the plane where the guide plate is located is perpendicular to the surface of the cover body relative to the bottom shell; the guide plate is located between the groove and the terminal panel, one end of the guide plate is connected to the first partition plate, and the other end of the guide plate is inclined toward the terminal panel.

5. The photovoltaic inverter according to claim 4, characterized in that: The power conversion circuit also includes a first communication circuit, which is accommodated in the third accommodating cavity and is arranged close to the terminal panel; the terminal panel also includes a first communication terminal; the first communication terminal passes through the terminal panel, and one end of the first communication terminal extending into the third accommodating cavity is electrically connected to the first communication circuit; the first communication terminal is used to transmit data in parallel to an external device; the other end of the guide plate is inclined toward the first communication terminal.

6. The photovoltaic inverter according to any one of claims 1 to 5, characterized in that: The multiple partition plates include a second partition plate, which divides the fourth accommodating cavity into a first cavity and a second cavity. The first cavity and the second cavity are respectively arranged adjacent to the third accommodating cavity. The first inductor is accommodated in the first cavity, and the second inductor is accommodated in the second cavity.

7. The photovoltaic inverter according to claim 6, characterized in that: The power module includes a first switch tube and a second switch tube, the first switch tube is electrically connected between the DC input terminal and the first inductor, and the second switch tube is electrically connected between the bus capacitor and the second inductor; the first switch tube is arranged close to the first inductor, and the second switch tube is arranged close to the second inductor.

8. The photovoltaic inverter according to any one of claims 1 to 7, characterized in that: The power conversion circuit further includes a plurality of relays; the plurality of relays are located between the circuit board and the bottom shell; The multiple partition plates include a third partition plate, and the second accommodating cavity and the third accommodating cavity are separated by the third partition plate; a thermal pad is provided at one end of the third partition plate facing the cover body, and the thermal pad is used to contact the circuit board; the multiple relays are distributed in two rows on both sides of the thermal pad.

9. The photovoltaic inverter according to claim 8, characterized in that: A metal bracket is further provided at one end of the third partition plate facing the cover body, the thermal pad is fixed to one end of the metal bracket facing the cover body, and the plurality of relays are distributed in two rows on both sides of the metal bracket.

10. The photovoltaic inverter according to any one of claims 1 to 9, characterized in that: The plurality of accommodating chambers further include a fifth accommodating chamber, the fifth accommodating chamber being disposed adjacent to the terminal panel and being located between the third accommodating chamber and the second accommodating chamber; The power conversion circuit further includes a second communication circuit, and the second communication circuit is accommodated in the fifth accommodation cavity; The terminal panel also includes a second communication terminal, which passes through the terminal panel. One end of the second communication terminal extending into the fifth accommodating cavity is electrically connected to the second communication circuit. The second communication terminal is used to transmit data serially to an external device.

11. The photovoltaic inverter according to any one of claims 1 to 10, characterized in that: The photovoltaic inverter also includes a switch, which is arranged in the housing, connected between the DC input terminal and the first inductor, and is used to connect or disconnect the electrical connection between the photovoltaic component and the power conversion circuit.

12. The photovoltaic inverter according to any one of claims 1 to 11, characterized in that: A chip resistor, a chip capacitor and a signal indicator light are arranged on one side of the circuit board facing the cover body, and the signal indicator light is used to indicate the working state of the photovoltaic inverter.

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