Inverter and glue sealing method thereof

Abstract

The application discloses an inverter and a glue pouring sealing method thereof. The glue pouring sealing method of the inverter comprises the following steps: providing a shell, the shell being provided with a first cavity and a circuit board installed in the first cavity, a gap being formed between the circuit board and the inner wall of the shell, and the shell being provided with a first opening and a second opening in communication with the first cavity on the side wall with a smaller area; placing the shell with the side wall with a smaller area upward, so that the first opening and the second opening are located at the top region of the first cavity; pouring the glue into the first cavity from the first opening, the glue filling the first cavity from bottom to top, and the gas in the first cavity being discharged from the second opening; stopping pouring the glue when the glue is filled; and respectively installing a plugging piece into the first opening and the second opening, so that a sealing fit is formed between the plugging piece and the opening before the glue is solidified.

Description

Technical Field

[0001] This invention relates to the field of power electronic equipment technology, and in particular to an inverter and its potting and sealing method. Background Technology

[0002] Inverters (such as microinverters used in photovoltaic power generation systems) are configured to convert direct current (DC) power generated by photovoltaic modules into alternating current (AC) power suitable for transmission to the grid or electrical loads. During operation, the power conversion circuitry and output filtering circuitry within a microinverter generate significant amounts of heat and electromagnetic interference. Therefore, in the structural design of microinverters, it is desirable to address issues related to heat dissipation, electromagnetic compatibility, and the protection of internal electronic components from environmental factors such as moisture and particulate contamination, either simultaneously or sequentially.

[0003] In one related technology, microinverters are typically constructed as a sandwich configuration, with an upper housing, a PCBA mainboard, and a lower housing stacked sequentially. To suppress electromagnetic interference generated by the output filtering circuit, the filtering area needs electromagnetic shielding. A typical solution is to install a separate metal shielding cover above the filtering area, but this increases material costs and assembly steps, occupies internal housing space, hinders the miniaturization of the microinverter, and impedes the flow of potting compound in the sandwich structure, leading to potting defects. Another typical solution is to set a rib on one side of the housing, allowing the rib to contact the opposite side to form a shielding cavity. However, this solution requires the rib to fit tightly against the opposite side to achieve effective shielding, placing high demands on mold and assembly precision. Furthermore, the tight fit also blocks the flow path of the potting compound. Yet another typical solution is to place a conductive gasket between the housing and the PCBA mainboard to achieve electrical connection and shielding. This also increases material costs and assembly steps, and the conductive gasket is prone to aging and failure over long-term use.

[0004] In another related technology, microinverters typically dissipate heat by filling a die-cast aluminum housing with thermally conductive potting compound. Heat-generating components on a PCBA are usually concentrated in the central area of ​​the circuit board, while the narrow edges of the housing are typically unoccupied. In existing potting processes, the potting port is usually located on the upper housing (top cover), and the equipment is placed horizontally for potting. The large horizontal flow area of ​​the adhesive easily leads to air bubbles being trapped within the adhesive, making it difficult to completely expel the gas from the cavities, thus negatively impacting heat dissipation. Residual air bubbles are often randomly distributed near the heat-generating components, severely affecting thermal conductivity. Current methods for addressing the air bubble problem mainly include vacuum potting and vibration venting. The former requires costly vacuum equipment, and the latter requires specialized vibration equipment, increasing the number of processes, time, and equipment investment. Furthermore, for high-viscosity potting compounds, the effectiveness of vibration venting is limited. In addition, after the die-cast aluminum housing is filled with potting compound, the thermal expansion of the compound can compress the components inside the housing, potentially causing damage. The glue outlet is usually sealed with an adhesive-backed metal sheet, which requires additional parts, and the adhesive is at risk of aging during long-term use. Summary of the Invention

[0005] To address the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide an inverter and its potting and sealing method, which can direct and focus air bubbles to non-critical heat dissipation areas without the need for vibration equipment, thereby reducing costs and improving heat dissipation.

[0006] To solve the above-mentioned technical problems, one technical solution adopted by the present invention is to provide a potting and sealing method for an inverter, comprising the following steps: A housing is provided, the housing having a first cavity and a circuit board mounted in the first cavity, a gap between the circuit board and the inner wall of the housing, and a first opening and a second opening communicating with the first cavity on the smaller side wall of the housing. The housing is placed with the smaller sidewall facing upwards, so that both the first opening and the second opening are located in the top region of the first cavity; Using the first opening as the potting port and the second opening as the venting port, the potting compound is injected into the first cavity through the first opening, and the potting compound fills the first cavity from bottom to top, while the gas in the first cavity is discharged through the second opening. Stop filling the potting compound once it is full. The sealing components are respectively inserted into the first opening and the second opening, and a sealing fit is formed between the sealing components and the openings before the potting compound cures. After the potting compound cures, a seal is formed between the sealing element and the opening through the cured potting compound.

[0007] Furthermore, after stopping the glue application and before installing the fasteners, a settling step is included: the housing is held in the aforementioned posture for a predetermined time, allowing residual air bubbles to rise along the gap between the circuit board and the inner wall of the first cavity under buoyancy, and accumulate in the top area near the smaller side wall.

[0008] Furthermore, the predetermined time is 1 to 5 minutes.

[0009] Furthermore, the heating components on the circuit board are concentrated in the middle area of ​​the circuit board, while there are no heating components in the top area of ​​the first cavity corresponding to the side wall.

[0010] Furthermore, before installing the fastener, a potting compounding step is included: applying potting compound from the first opening and / or the second opening so that uncured potting compound adheres to the first opening and the second opening.

[0011] Furthermore, the potting compound is a thermally conductive potting compound.

[0012] Furthermore, the first opening and / or the second opening are threaded holes, the sealing element is a threaded fastener, and the sealing fit is the potting compound filling the gap between the thread of the threaded fastener and the thread of the threaded hole.

[0013] Furthermore, the housing includes a first housing and a second housing opposite to the first housing. A first shielding member is provided on the side of the first housing facing the second housing, and a second shielding member is provided on the side of the second housing facing the first housing. A first gap exists between the first shielding member and the second shielding member. The first housing, the second housing, the first shielding member, and the second shielding member enclose a second cavity. The area of ​​the circuit board to be shielded in the micro inverter extends into the second cavity through the first gap.

[0014] Furthermore, there is a second gap between the first shielding component and the circuit board, and a second gap between the second shielding component and the circuit board; the potting compound flows into the interior of the second cavity through the second gap and / or the third gap, filling the area of ​​the second cavity located above and below the circuit board.

[0015] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is: to provide an inverter, comprising: The housing has a first cavity; A circuit board is installed in the first cavity, and there is a gap between the circuit board and the inner wall of the housing. The housing is provided with a first opening and a second opening that communicate with the first cavity. Encapsulating adhesive is used to fill the first cavity; The first fastener and the second fastener are respectively installed in the first opening and the second opening; There are glue-filling gaps between the first fastener and the first opening, and between the second fastener and the second opening. The glue-filling gaps are filled with cured potting compound to form a sealed structure. The area within the first cavity near the smaller sidewall has a bubble accumulation chamber.

[0016] The inverter and its potting and sealing method provided by this invention can achieve the following beneficial effects: By placing the housing upright with its narrow sidewalls facing upwards, the cross-sectional area of ​​the first cavity in the horizontal direction is minimized. During injection, the potting compound fills the first cavity in a manner similar to an upward flow through a vertical pipe, reducing disturbances and eddies during the flow of the compound and lowering the possibility of air bubbles being entrained inside. Simultaneously, since both the first and second openings are located on the narrow sidewalls at their highest positions, gas can directly reach the exhaust port vertically, facilitating complete gas discharge without the need for vacuum or vibration equipment.

[0017] After potting is stopped, a settling step is performed to allow residual air bubbles to rise along the gap between the circuit board and the inner wall of the housing under buoyancy, accumulating in the top area near the narrow sidewall. Since this area is pre-designed as a non-critical heat dissipation area without heat-generating components, the impact of bubble accumulation on the overall heat dissipation performance of the inverter is minimized. These accumulated bubbles form tiny cavities after the potting compound cures, which act as buffer zones to absorb the volume increase caused by thermal expansion of the potting compound, reducing the possibility of component failure due to compression. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the inverter structure provided by one or more exemplary embodiments of the present invention.

[0019] Figure 2 This is a disassembly diagram of an inverter provided by one or more exemplary embodiments of the present invention.

[0020] Figure 3 This is a schematic diagram of the layout of the first shielding member provided by one or more exemplary embodiments of the present invention.

[0021] Figure 4This is a schematic diagram of the layout of the second shielding member provided by one or more exemplary embodiments of the present invention.

[0022] Figure 5 yes Figure 1 Sectional view of AA.

[0023] Figure 6 yes Figure 5 A magnified schematic diagram of part B in the middle.

[0024] Figure 7 This is a process flow diagram of the potting and sealing method for an inverter provided by one or more exemplary embodiments of the present invention.

[0025] The diagrams in the instruction manual are labeled as follows: Housing 100; First opening 101; Second opening 102; First housing 110; Bottom wall 111; Side wall 112; First side wall 112a; Second housing 120; Top wall 121; Transformer clearance slot 122; Capacitor clearance slot 123; Inductor clearance slot 124; Heat sink 125; AC connector 126; DC connector 127; First cavity 130; Second cavity 131; Shielding cavity 132; First shielding component 141; Second shielding component 142; First extension section 143; Second extension section 144; Adhesive through hole 145; Second gap D1; Third gap D2; Circuit board 200. Detailed Implementation

[0026] The following disclosure provides various embodiments or instances for implementing different features of this application. Specific examples of components and arrangements will be described below to simplify this application. Of course, these are merely examples and are not intended to limit this application. For example, in the following description, forming a first component above or on a second component may include embodiments where the first and second components are in direct contact, or embodiments where other components may be formed between the first and second components such that the first and second components are not in direct contact. Additionally, reference numerals and / or characters may be repeated in various instances within this application. Such repetition is for simplification and clarity and does not, in itself, indicate a relationship between the various embodiments and / or configurations.

[0027] Furthermore, spatial relation terms such as "below," "under," "below," "above," and "above" may be used herein to readily describe the relationship between one element or component and another element (or component) or component (or component) as shown in the figure. In addition to the orientations shown in the figure, spatial relation terms will encompass various different orientations of the device in use or operation. The device may be positioned in other ways (rotated 90 degrees or in other orientations) and will be interpreted accordingly through the spatial relation descriptors used herein.

[0028] Furthermore, the technical portions described in this application and the appended claims are primarily the improved technical portions of this application, and do not limit the object protected by this application to only having these technical portions. Other known essential components (structures and / or methods) and / or non-essential components of the object protected, besides the technical portions described in this application and the appended claims, are not included in this application and the appended claims because they do not fall within the scope of improvement of this application; however, this does not mean that the object protected by this application does not possess these known components.

[0029] Example 1 Please refer to Figure 1 and Figure 2 , Figure 1 A schematic diagram of the structure of an inverter provided by one or more embodiments is shown as an example. Figure 2 Exemplary disassembly diagrams of inverters provided in one or more embodiments are shown. In the illustrated embodiments, the inverter may be configured to include a housing 100 and a circuit board 200 disposed inside the housing 100. The housing 100 may be configured to include a first housing 110 and a second housing 120 disposed opposite to the first housing 110. The first housing 110 and the second housing 120 may be assembled together using any detachable assembly structure known in the art (e.g., but not limited to threaded connections, snap-fit ​​connections, or screw and locating post connections), so as to facilitate separation for internal maintenance or repair, thereby providing operational convenience for the installation, removal, or replacement of the circuit board 200.

[0030] When the first housing 110 and the second housing 120 are closed together, they jointly define a first cavity 130. The first cavity 130 is configured to accommodate the circuit board 200 and the potting compound (not shown in the figure) subsequently injected. In a specific implementation, the first housing 110 is configured as the upper housing component of the inverter structure, while the corresponding second housing 120 is used as the lower housing component of the inverter structure. The circuit board 200 is arranged in the first cavity 130 formed between the first housing 110 and the second housing 120. At the same time, a pre-defined gap is maintained between the circuit board 200 and the inner walls of the first housing 110 and the second housing 120. The existence of these gaps is to fully accommodate the potting compound, which will be described in detail in the corresponding sections below, so that the potting compound is fully injected into the gaps, thereby achieving multiple functions such as effective fixation, heat dissipation, and insulation protection of the circuit board 200.

[0031] However, those skilled in the art should readily understand that in various alternative embodiments covered by the present invention, the vertical relative positions of the first housing 110 and the second housing 120 are not fixed but can be flexibly interchanged and adjusted according to specific installation requirements, space layout limitations, or heat dissipation considerations in actual application scenarios. Such interchange of positions will not have any substantial adverse effect on the overall implementation effect of the present invention or its intended technical purpose, nor will it cause the technical features described in the present invention to lose their due function or role. Therefore, such interchangeable adjustments should be considered as falling within the reasonable variation scope explicitly authorized and covered by the present invention.

[0032] To facilitate a more intuitive and clear understanding of the spatial configuration of the inverter housing 100 structure and the relative positional relationships between its various components provided by this invention, the following description will refer to a common rectangular or quasi-rectangular structure as an exemplary architecture to further describe the inverter housing 100 structure. However, those skilled in the art will readily recognize that although the directional terms used in the following description (e.g., top wall, bottom wall, side wall, etc.) refer to the rectangular or quasi-rectangular housing 100 structure, their use is merely for the convenience of description and understanding and does not constitute any limitation on the shape, proportion, or construction method of the housing 100 structure of this invention. In alternative embodiments, the housing 100 can be constructed in any other suitable geometric shape (e.g., but not limited to, circular, elliptical, polygonal, or irregular shapes), and the corresponding structural features under these alternative shapes should also be considered within the reasonable scope of variations of the technical solution of this invention.

[0033] As is known in the art, the housing 100 of a microinverter can generally be considered as having a large top wall 121 and a large bottom wall 111, and a plurality of smaller side walls 112 formed between the edges of the top wall 121 and the bottom wall 111. The larger top wall 121 and bottom wall 111 extend generally horizontally in normal operating conditions of the inverter, while the smaller side walls 112 extend generally vertically and connect the top wall 121 and bottom wall 111 to each other, thereby collectively enclosing the internal accommodating space of the housing 100. In practical applications of the inverter, the corresponding side walls 112 are typically provided with connector interfaces for AC and DC power input / output, such as AC connector 126 and DC connector 127. These connector interfaces are configured to electrically connect to external power lines to achieve DC power input and AC power output.

[0034] More specifically, in some embodiments, the first housing 110 of the inverter may be configured to include a large bottom wall 111 and a plurality of first side walls 112a extending upward from each edge of the bottom wall 111 (e.g., four edges in the case of a rectangular housing 100). The first side walls 112a and the bottom wall 111 together form a recessed structure with an opening facing the second housing 120. This recessed structure has a predetermined depth in the height direction, which is configured to be at least sufficient to accommodate the thickness of the circuit board 200 and the mounting height of electronic components that may be disposed at the bottom of the circuit board 200. That is, the first housing 110 itself constitutes an open container with a bottom and four side walls 112, the opening of which points towards the side where the second housing 120 is located.

[0035] Correspondingly, the second housing 120 may be configured to include the larger top wall 121, and in some embodiments, the second housing 120 may also selectively include a plurality of second side walls 112 extending downward from each edge of the top wall 121, the second side walls 112 and the top wall 121 together forming another groove structure with an opening facing the first housing 110. When the first housing 110 and the second housing 120 are fitted together relative to each other along their respective opening directions, the first side wall 112a in the first housing 110 and the second side wall 112 in the second housing 120 abut or cooperate with each other, jointly defining the internal accommodating space of the housing 100, which is the aforementioned first cavity 130. Of course, in alternative embodiments, the complete recessed structure may be provided solely by the first housing 110, while the second housing 120 is constructed as a generally flat cover-like member that mates with the opening edge of the first housing 110 to close the recessed structure; alternatively, the complete recessed structure may be provided solely by the second housing 120, while the first housing 110 is constructed as a generally flat cover-like member that mates with the opening edge of the second housing 120 to close the recessed structure. This alternative solution also achieves the basic function of accommodating the circuit board 200 and should therefore be considered within the scope of the present invention.

[0036] After the circuit board 200 is arranged inside the first cavity 130, the main planes of the circuit board 200 (i.e., its upper and lower surfaces) face the bottom wall 111 (i.e., the bottom wall 111 of the first housing 110) and the top wall 121 (i.e., the top wall 121 of the second housing 120), respectively, while the respective side edges of the circuit board 200 face the respective side walls 112 of the housing 100. Based on the thin-film design requirements of microinverters, the extension dimension of each side wall 112 of the housing 100 (including the first side wall 112a of the first housing 110 and / or the second side wall 112 of the second housing 120) in the height direction is consistent with the thickness direction of the circuit board 200, and this dimension in the height direction is usually configured to be much smaller than the dimension of the housing 100 in the horizontal direction (e.g., the length dimension). Correspondingly, the internal dimensions of the aforementioned first cavity 130 in the height direction are also configured to be much smaller than its dimensions in the horizontal direction. This makes the first cavity 130 present a flat, roughly plate-shaped internal space configuration. This flat configuration is beneficial to reducing the overall height of the inverter and facilitating its installation on the back of the photovoltaic module.

[0037] In some embodiments, the second housing 120 may also be provided with a plurality of clearance grooves. These clearance grooves are configured to provide clearance space for protruding electronic components on the circuit board 200 when the second housing 120 is closed onto the first housing 110, thereby preventing physical interference between the second housing 120 and these electronic components. Specifically, these clearance grooves are constructed as protruding structures recessed from the main plane of the top wall 121 of the second housing 120 toward a direction away from the first housing 110 (i.e., outward and upward), thereby forming corresponding cavities on the inner surface of the second housing 120. Depending on the height and layout of different types of components on the circuit board 200, these clearance slots can be specifically configured as different types of clearance structures, such as, but not limited to: transformer clearance slot 122 for clearance of transformer components, capacitor clearance slot 123 for clearance of capacitor components (e.g., electrolytic capacitors or film capacitors), inductor clearance slot 124 for clearance of inductor components (e.g., power inductors or filter inductors), and corresponding clearance slots for clearance of other electronic components that may protrude from the surface of the circuit board 200 (e.g., but not limited to relays, connectors, semiconductor switching devices, etc.). These clearance slots are each arranged in the area of ​​the top wall 121 of the second housing 120 that spatially corresponds to the mounting position of the corresponding component on the circuit board 200, so that these protruding components can be fully accommodated when the second housing 120 is closed.

[0038] Furthermore, a plurality of heat sinks 125 may be provided on the outer surface of the second housing 120. These heat sinks 125 are configured to increase the heat exchange area between the second housing 120 and the external ambient air, thereby improving the passive heat dissipation efficiency of the inverter. More specifically, the top wall 121 of the second housing 120 can be considered to have a low-level region relatively close to the first housing 110 (i.e., the main area of ​​the top wall 121 without clearance slots) and a high-level region relatively far from the first housing 110 (i.e., the protruding area of ​​the top wall 121 formed by the outward protrusion of the clearance slots). The heat sinks 125 are provided on the outer surface of the top wall 121, and are preferably arranged in the low-level region, because the low-level region has a large continuous flat surface area, which is conducive to the regular arrangement of the heat sinks 125 and the arrangement of maximized heat dissipation area. In some embodiments, the heat sinks 125 may also be arranged to connect between the outer surfaces of each clearance slot (i.e., the top and side surfaces of the protruding structure), thereby forming an interconnected integrated heat dissipation structure between the outer surfaces of the clearance slots and the heat sinks 125. This arrangement not only further increases the effective heat dissipation area, but also forms a reinforcing rib structure by connecting the outer surfaces of each clearance slot with the heat sink 125, thereby enhancing the overall structural rigidity and strength of the second housing 120 and making it less prone to deformation when subjected to external loads or the thermal expansion force of the internal potting compound.

[0039] In some embodiments, for ease of manufacturing and assembly, the heat sink 125 and the clearance groove can be integrally formed with the second housing 120 using the same die-casting process. That is, the heat sink 125, the clearance groove, and the top wall 121 and side wall 112 of the second housing 120 are all integral structures formed by the same mold in the same die-casting process, without any subsequent additional installation steps. However, in alternative embodiments, the heat sink 125 and / or the clearance groove can also be additionally provided to the second housing 120 by other suitable manufacturing methods (e.g., but not limited to machining, welding, bonding, or threaded connection), and these alternative methods can achieve essentially the same functional effect.

[0040] Based on the detailed description of the overall structure of the inverter above, the following section combines... Figures 3 to 6 The electromagnetic shielding structure in the inverter provided by one or more embodiments of the present invention will be described in more detail below. As those skilled in the art will understand, the power conversion circuit and output filter circuit in the inverter will generate electromagnetic interference during operation. If not properly shielded and suppressed, this electromagnetic interference may propagate to the outside of the inverter through radiation or conduction, thereby adversely affecting other surrounding electronic equipment. Therefore, in the structural design of the inverter, it is usually necessary to perform electromagnetic shielding treatment on the area where the output filter circuit is located.

[0041] Please see Figure 3 and Figure 4 , Figure 3 A schematic diagram of the layout of the first shield 141 in an inverter provided by one or more embodiments is shown as an example. Figure 4A schematic diagram of the layout of a second shield 142 in an inverter provided by one or more embodiments is illustrated. In the illustrated embodiment, the first shield 141 is integrally formed on the side of the first housing 110 facing the circuit board 200 (in the direction of the second housing 120) (i.e., the inner surface side of the first housing 110). Similarly, the second shield 142 is integrally formed on the side of the second housing 120 facing the circuit board 200 (in the direction of the first housing 110) (i.e., the inner surface side of the second housing 120). The term "integrated" means that the first shield 141 and the first housing 110, and the second shield 142 and the second housing 120, are formed as a single, inseparable structural unit through a single molding process (e.g., die casting), rather than by subsequently welding, bonding, screwing, or other mechanical connection methods to additionally attach separately manufactured shields to the housing 100. This one-piece manufacturing method eliminates the material procurement, inventory management, and assembly processes required for separate shielding components, reducing manufacturing costs and assembly time. In addition, since there are no seams, gaps, or contact interfaces between the shielding component and the housing 100, electrical continuity is maintained to the maximum extent, which helps ensure the consistency and reliability of the shielding structure throughout the entire operating frequency range.

[0042] Furthermore, after the first housing 110 and the second housing 120 are closed relative to each other, the first shield 141 is located above the circuit board 200 in the vertical direction, while the second shield 142 is located below the circuit board 200 in the vertical direction. The first shield 141 and the second shield 142 are arranged spatially opposite each other, and a first gap (not shown) is formed between them. The size of the first gap (i.e., the vertical distance between the lower end of the first shield 141 and the upper end of the second shield 142) is set to be greater than the thickness of the circuit board 200, so that the circuit board 200 can pass through the first gap without contacting or interfering with the first shield 141 or the second shield 142.

[0043] Furthermore, the first shielding member 141 and the second shielding member 142 are each configured as an L-shaped bent structure. Specifically, both the first shielding member 141 and the second shielding member 142 can be considered to include a first extension segment 143 extending along a first direction and a second extension segment 144 bent from the end of the first extension segment 143 and extending along a second direction. The angle between the second direction and the first direction is approximately 90 degrees, thereby making the first shielding member 141 and the second shielding member 142 appear as an L-shaped structure in a top view or in a horizontal projection plane. However, those skilled in the art should understand that the specific construction of the first shielding member 141 and the second shielding member 142 should not be limited to the above-described L-shaped structure. In other alternative embodiments, the first shield 141 and the second shield 142 may each be configured as any other suitable shape that can be used together with the shielding layer of their corresponding housing 100 and circuit board 200 to form a shielding cavity, such as, but not limited to, an arc-shaped bending structure, a U-shaped bending structure, a wave-shaped bending structure, or a continuous enclosure structure extending circumferentially along the housing 100, as long as these structures can together with the shielding layer of the circuit board 200 define a generally enclosed space to accommodate the area to be shielded.

[0044] A portion of the inner wall surface of the first housing 110 surrounding the first shielding member 141 (e.g., the bottom wall 111 and corresponding side walls 112 that together with the first shielding member 141 form a rectangular structure), a portion of the inner wall surface of the second housing 120 surrounding the second shielding member 142 (e.g., the top wall 121 and corresponding side walls 112 that together with the second shielding member 142 form a rectangular structure), the first shielding member 141, and the second shielding member 142 together define and enclose a second cavity 131. The second cavity 131 spatially constitutes a generally enclosed receiving space, and the area of ​​the circuit board 200 to be shielded (e.g., may include an output filter circuit area) is positioned inside the second cavity 131 after the circuit board 200 passes through the first gap. Because the boundary walls of the second cavity 131 can provide a certain degree of shielding effect for electromagnetic waves emitted from the area to be shielded within it.

[0045] Please see Figure 5 and Figure 6To further enhance the shielding effect, a shielding layer (not shown) may also be provided on the circuit board 200. In some embodiments, the shielding layer may be configured as a conductive layer inside or on the surface of the circuit board 200, such as, but not limited to, a ground copper foil (i.e., a copper foil layer used to provide a ground reference potential), and the horizontal extension of the shielding layer at least covers the area where the area to be shielded is located. When the first housing 110 and the second housing 120 are closed, the shielding layer and the first housing 110 and the first shielding member 141, as well as the shielding layer and the second housing 120 and the second shielding member 142, together enclose a shielding cavity 132. In other words, the shielding cavity 132 is a spatial area jointly defined by a portion of the inner wall surface of the first housing 110, the first shielding member 141, a portion of the inner wall surface of the second housing 120, the second shielding member 142, and the shielding layer of the circuit board 200. In this way, the shielding cavity 132 forms a substantially closed conductive housing 100. The switching power supply circuit (typically located on the circuit board 200 in an area outside the shielding cavity 132) generates high-frequency electromagnetic interference during operation, which radiates outwards as electromagnetic waves. If these electromagnetic waves directly strike the output filter circuit area located inside the shielding cavity 132, they may adversely affect the normal operating performance of the filter, for example, causing additional noise components at the filter output or shifting the filter characteristics. By housing the output filter circuit within the shielding cavity 132 made of conductive material, the first shield 141, the second shield 142, and the shielding layer of the circuit board 200 together constitute a conductive barrier between the external interference source and the filter to be protected.

[0046] It is worth noting that in this embodiment, the first shield 141 is not in close contact with the lower surface of the circuit board 200, but is left with a second gap D1. Similarly, a third gap D2 is left between the second shield 142 and the upper surface of the circuit board 200. The first gap, the second gap D1, and the third gap D2 are spatially interconnected, forming a channel for fluid (potting compound) communication between the internal space of the shield cavity 132 and the rest of the first cavity 130 (i.e., the space outside the shield cavity 132). In some embodiments, the dimensions of the second gap D1 and / or the third gap D2 may be in the range of 0.3 mm to 1.5 mm.

[0047] In summary, through the combined action of the integrally formed first shielding member 141 of the first housing 110, the integrally formed second shielding member 142 of the second housing 120, and the shielding layer of the circuit board 200, the provided inverter can form an effective shielding cavity 132 without the need for any additional parts such as independent shielding covers, shielding plates, or conductive pads. This provides reliable electromagnetic shielding protection for the areas of the circuit board 200 to be shielded (e.g., the output filter circuit area). Simultaneously, since predetermined gaps are maintained between the first shielding member 141, the second shielding member 142 and the circuit board 200, as well as between the first shielding member 141 and the second shielding member 142, these gaps can serve as flow channels for the potting compound in the subsequent potting process, ensuring that the internal area of ​​the shielding cavity 132 can also be filled with potting compound.

[0048] Furthermore, the inverter also includes potting compound, which is injected into the first cavity 130 between the first housing 110 and the second housing 120, thereby completely or partially encapsulating the circuit board 200 and other electronic components (such as, but not limited to, transformers, inductors, capacitors, semiconductor switching devices, etc.) within the first cavity 130 in the cured potting compound. The potting compound can flow into the interior of the shielding cavity 132 through the aforementioned second gap D1 and / or third gap D2, thereby filling the area above and below the circuit board 200 within the shielding cavity 132, and further filling the location of the first gap. That is, through the fluid communication channel formed by the first gap, the second gap D1, and the third gap D2, the potting compound can flow and fill freely in almost the entire area of ​​the first cavity 130 (including the first cavity 130 and the second cavity 131), without creating potting dead zones inside or around the shielding cavity 132 due to the presence of the shielding structure.

[0049] After the potting compound is injected and cured, both the first shield 141 and the second shield 142 form a tight physical contact with the cured potting compound (the first shield 141 and the second shield 142 are embedded in the cured potting compound). Since the first housing 110 and the second housing 120 are both made of metal materials with good thermal conductivity (e.g., die-cast aluminum alloy), and the potting compound is also selected as a thermally conductive potting compound with good thermal conductivity, the heat generated in the shielded area of ​​the circuit board 200 is first transferred from the shielded area to the potting compound in contact with it, and then simultaneously transferred upwards to the first shield 141 and the first housing 110, and downwards to the second shield 142 and the second housing 120 by the potting compound, and finally dissipated to the surrounding environment by the outer surfaces of the first housing 110 and the second housing 120. Because the heat is conducted in both upward and downward directions simultaneously, compared with the prior art scheme that only dissipates heat through one side (e.g., only through the lower housing), this double-sided heat conduction path significantly increases the heat dissipation area, thereby improving the heat dissipation efficiency of the inverter.

[0050] Example 2 The following will refer to Figures 1 to 7 The potting and sealing method for inverters provided by one or more embodiments of the present invention will be described in detail. As those skilled in the art will understand, potting (or encapsulation) is an important process in the manufacturing of inverters. Its purpose is to fix the circuit board 200, protect electronic components from moisture and contaminants, and conduct heat from heat-generating components to the housing 100 for heat dissipation by injecting potting compound into the housing 100. However, if air bubbles are mixed into the potting compound during the potting process, these air bubbles may remain inside the potting compound after curing, thereby adversely affecting the heat dissipation effect. Therefore, how to effectively control the distribution and position of air bubbles is one of the issues that needs to be addressed in the potting process.

[0051] Please refer to Figure 7 , Figure 7 A process flow diagram of the potting sealing method provided in one or more embodiments is illustrated by way of example. The potting sealing method can be applied to the inverter structure described and shown above, and can also be applied to other electronic devices with similar housing 100 structures and circuit board 200 arrangements. In the illustrated embodiment, the potting sealing method for the inverter includes the following steps: S100, Provide housing 100.

[0052] In step S100, a housing 100 is first provided, which is configured to have a first cavity 130 and a circuit board 200 mounted inside the first cavity 130. A predetermined gap is maintained between the circuit board 200 and the inner sidewall 112 of the housing 100. These gaps are inherent gap structures of the circuit board 200 in its normal mounting state within the housing 100 because its external dimensions are smaller than the internal dimensions of the first cavity 130, and are not grooves or channels additionally processed specifically for potting purposes. Specifically, these gaps include a first gap between the circuit board 200 and the large surface (bottom wall 111) of the first housing 110, a second gap between the circuit board 200 and the large surface (top wall 121) of the second housing 120, and third gaps between the periphery of the circuit board 200 and each of the sidewalls 112 of the housing 100.

[0053] The housing 100 is provided with a first opening 101 and a second opening 102 communicating with the first cavity 130 (see...). Figure 1 These two openings are located on a side wall 112 of the housing 100 that has a smaller area (relative to the bottom wall 111 and the top wall 121) (hereinafter referred to as the narrow side wall 112). In this embodiment, each side wall 112 of the housing 100 is a narrow side wall 112, and the first opening 101 and the second opening 102 are shared on one of the narrow side walls 112. The first opening 101 and the second opening 102 are respectively configured as an injection inlet for potting compound and an outlet for gas in the first cavity 130 during a subsequent potting step.

[0054] In some embodiments, the first opening 101 and / or the second opening 102 may be configured as threaded holes with internal threads, both arranged at approximately the same height on the narrow sidewall 112. When the housing 100 is in the particular placement posture described below, both the first opening 101 and the second opening 102 are located in the top region of the first cavity 130 (i.e., the highest position region in the direction of gravity).

[0055] In some embodiments, heat-generating components (such as, but not limited to, power switching devices, transformers, inductors, etc.) on the circuit board 200 are concentrated in the middle region of the circuit board 200, while the region of the first cavity 130 corresponding to the narrow sidewall 112 on the housing 100 is almost free of any heat-generating components. The technical significance of this arrangement will be further explained in step S400 below.

[0056] S200, placed sideways.

[0057] In step S200, the housing 100 is placed with its narrow sidewall 112 facing upwards, such that the narrow sidewall 112 of the housing 100 is located at the uppermost position of the entire housing 100 in the direction of gravity. In this placement, the first opening 101 and the second opening 102 (since both are located on the narrow sidewall 112) are naturally located in the top region of the first cavity 130, that is, the highest position region in the direction of gravity.

[0058] More specifically, in conventional potting operations, the housing 100 is typically placed horizontally, with the potting port located in the middle of the top of the housing 100. The potting compound is injected from the potting port on the top wall 121 and flows downwards under gravity. In the method of this embodiment, the housing 100 is placed in a sideways position, such that the narrow sidewall 112 with a smaller area on the housing 100 is flipped upwards. In this placement posture, the projected area of ​​the first cavity 130 on the horizontal plane is minimized. This feature is of great significance for controlling air bubbles during the subsequent potting process, and its specific principle will be explained in detail in steps S300 and S400 below.

[0059] S300, inject potting compound.

[0060] In step S300, the potting compound is injected into the first cavity 130 through the first opening 101 as the filling port and the second opening 102 as the venting port. During this injection process, the potting compound flows downward from the first opening 101 under its own gravity, gradually filling the internal space of the first cavity 130 from bottom to top as the injection volume increases. Simultaneously, as the potting compound level rises, the air originally inside the first cavity 130 is gradually pushed upward and compressed, eventually being expelled to the external environment through the second opening 102, which is located at the highest position.

[0061] In this step, because the housing 100 is placed on its side and the horizontal cross-sectional area of ​​the first cavity 130 is minimized, the horizontal flow range of the potting compound during its ascent is significantly reduced. This means that the flow front of the potting compound is narrower in the horizontal direction, and its flow behavior is closer to upward flow in a vertical pipe than to expanding flow on a large horizontal plane. This change in flow pattern helps to reduce flow disturbance and eddies in the horizontal direction of the adhesive, thereby reducing the possibility of air bubbles being entrained inside the adhesive. At the same time, since the gas is discharged from the second opening 102 at the top, the gas discharge path is directly upward in the vertical direction to the exhaust port. The gas does not need to travel a long distance laterally to reach the exhaust port, which further promotes the full discharge of gas.

[0062] In some embodiments, the potting compound used is a thermally conductive potting compound. This thermally conductive potting compound has good thermal conductivity, effectively transferring the heat generated by the heat-generating components to the surface of the housing 100; after curing, it forms a solid medium with certain strength and sealing performance, thus simultaneously providing sealing and protection. The specific material composition and performance parameters of the thermally conductive potting compound can be appropriately selected based on factors such as the inverter's specific operating temperature range, insulation requirements, and mechanical strength requirements, and no restrictions are imposed in this regard.

[0063] For an inverter structure including the first shield 141 and the second shield 142 described above, during the process of injecting potting compound into the first cavity 130, the potting compound gradually flows into the interior of the shield cavity 132 through the second gap D1 and / or the third gap D2, filling the area of ​​the shield cavity 132 located above and below the circuit board 200. In some embodiments, at least one through hole 145 (see...) can be formed on the first shield 141 and the second shield 142. Figure 5 The glue-passing holes 145 can be provided at the bending points of the first shielding member 141 and / or the second shielding member 142. During the potting process, in addition to flowing into the shielding cavity 132 along the second gap D1 and / or the third gap D2, the potting adhesive can also directly pass through the glue-passing holes 145 on the first shielding member 141 and / or the second shielding member 142 into the interior of the shielding cavity 132, thereby enabling the potting adhesive to fill the areas above and below the circuit board 200 in the shielding cavity 132 more quickly and evenly. It should be understood that the number, diameter, and specific position of the glue-passing holes 145 on the shielding member can be set according to actual needs and are not limited in any way.

[0064] S400, stop dispensing and let stand.

[0065] In step S400, the potting operation is stopped when the potting compound is injected until the first cavity 130 is filled, for example when the potting compound begins to overflow from the first opening 101 or the second opening 102 located at the top.

[0066] After the potting process is stopped and before the sealing element is installed, the potting sealing method may optionally include a settling step: allowing the housing 100 to remain in the side-standing position set in step S200 and settling in that position for a predetermined period of time. In some embodiments, the predetermined time may be set to a range of 1 to 5 minutes. Of course, the settling time can be appropriately adjusted according to factors such as the specific viscosity of the potting compound used, the bubble rise rate, and the specific geometric dimensions of the housing 100, and is not strictly limited to the range of 1 to 5 minutes mentioned above.

[0067] During the settling process, any remaining trace air bubbles that may be present in the first cavity 130 will slowly move upwards along the gap between the circuit board 200 and the inner wall of the first cavity 130 under the influence of buoyancy. Since the housing 100 is placed on its side, the highest point of the first cavity 130 in the vertical direction is located in the top region near the narrow sidewall 112. Therefore, the final aggregation point of these bubbles under buoyancy will be the highest point region of the first cavity 130. As mentioned earlier, since this area is pre-designed as a non-critical heat dissipation area without any heat-generating components, the impact of bubble aggregation here on the overall heat dissipation performance of the inverter is relatively limited. Even if the bubbles cannot be completely expelled, their final location will not substantially obstruct the heat dissipation path of the heat-generating components.

[0068] Furthermore, these bubbles gathered at the top of the narrow sidewall 112 will form bubble aggregation cavities after the potting compound cures. These cavities are formed by residual bubbles rising and accumulating at the highest point of the first cavity 130 due to buoyancy during the potting process, and are retained after the potting compound cures. These cavities act as buffer zones to absorb the volume increase caused by the thermal expansion of the potting compound due to temperature rise. Specifically, when the temperature of the potting compound rises, its volume expands. If the first cavity 130 is completely filled with potting compound without any compressible space, the pressure generated by the expansion will directly act on the circuit board 200 and electronic components, potentially causing components to fail or be damaged due to excessive stress. However, through the cavity structures formed by the bubble aggregation, some of the volume increase can be pushed into these cavities when the potting compound expands, thereby effectively reducing the compressive stress applied to the circuit board 200 and components due to the expansion of the potting compound, and reducing the possibility of component failure or damage due to excessive stress.

[0069] S500, install the sealing component.

[0070] Before the potting compound has fully cured (i.e., while the potting compound is still in a fluid, uncured state), the sealing element is inserted into the first opening 101 and the second opening 102, respectively, so that a preliminary mating relationship is formed between the sealing element and the corresponding opening. In some embodiments, the sealing element may be configured as a threaded fastener (e.g., but not limited to, a flathead screw or a countersunk screw), and both the first opening 101 and the second opening 102 may be configured as threaded holes with internal threads. The threaded fastener is screwed into the corresponding threaded hole by a rotational operation until its head abuts against the outer surface of the housing 100 or reaches a predetermined torque.

[0071] Before inserting the threaded fastener, the potting sealing method may optionally include a filler step: applying a small amount of potting compound from the first opening 101 and / or the second opening 102, such that a sufficient amount of uncured potting compound adheres around and inside the openings. The purpose of this filler step is to ensure that sufficient uncured potting compound is available to fill the minute gaps between the threads when the threaded fastener is screwed in, thereby ensuring the integrity and reliability of the seal.

[0072] When a threaded fastener is screwed into a threaded hole, the potting compound, still in an uncured fluid state, is squeezed by the threads of the fastener and forced into the tiny gaps (filling gaps) between the external threads of the fastener and the internal threads of the threaded hole. Since these gaps are typically micrometer-sized, the uncured potting compound, due to its low viscosity and good flowability, can completely fill these gaps, forming a seal. This process is similar to the principle of conventional thread sealants, but the difference is that the method of this invention utilizes the inherent flowability of the potting compound to achieve a seal, without the need for any additional specialized thread sealant or gasket.

[0073] S600, cured to form a seal.

[0074] The housing 100 is kept in its upright position and left to stand for a sufficient period of time until the potting compound has completed its curing process. Once fully cured, the potting compound filling the threaded gaps transforms from a fluid state to a solid state. Regardless of whether it undergoes slight volume shrinkage or expansion during curing, the cured potting compound firmly fills the threaded gaps, forming a complete and continuous solid sealing ring. This solid sealing ring completely seals all possible leakage paths between the threaded fastener and the threaded hole (including the gap between the thread crest and root, the gap between the thread flanks, etc.), thereby achieving a reliable sealing effect. Simultaneously, the cured potting compound also adheres to the threaded fastener and housing 100, preventing the threaded fastener from loosening under vibration or impact.

[0075] At this point, the potting and sealing operation of the inverter is complete. Through the above method, not only is potting protection achieved for the circuit board 200 and electronic components within the first cavity 130, but also the directional aggregation and control of air bubbles are achieved through the side-standing and stationary placement steps. Furthermore, low-cost and reliable sealing of the potting port is achieved by filling the thread gaps with uncured potting compound.

[0076] Based on the description of the above embodiments, the inverter and its potting and sealing method provided by the present invention can achieve one or more of the following beneficial effects: According to the inverter structure provided by the present invention, by providing an integrally formed first shielding component on a first housing and an integrally formed second shielding component on a second housing, and by having the first and second shielding components, together with the shielding layer on the circuit board, form a shielding cavity, electromagnetic shielding of the area to be shielded on the circuit board can be achieved without the need for additional parts such as independent shielding covers, shielding plates, or conductive pads. This solution reduces the number of parts, lowers material costs and assembly processes, and avoids the space occupied by independent shielding covers, which is beneficial for the miniaturization design of the inverter.

[0077] According to the inverter structure provided by the present invention, gaps of predetermined sizes are maintained between the first shield and the circuit board, between the second shield and the circuit board, and between the first shield and the second shield. These gaps are spatially interconnected, forming a channel for the flow of potting compound. In this way, the potting compound can flow into the interior of the shielding cavity through the aforementioned gaps during the potting process, filling the entire area above and below the circuit board within the shielding cavity, avoiding the formation of dead zones that the potting compound cannot reach inside the shielding cavity, and improving heat dissipation performance.

[0078] According to the inverter structure provided by the present invention, after the potting compound is cured, both the first shield and the second shield are embedded in the cured potting compound, forming a thermally conductive contact interface with the potting compound. This provides a thermally conductive path for the heat generated in the area to be shielded to be conducted in both upward and downward directions, forming a double-sided thermally conductive structure and increasing the effective heat dissipation area.

[0079] According to the potting and sealing method provided by the present invention, by placing the housing upright with its narrow sidewalls facing upwards, the cross-sectional area of ​​the first cavity in the horizontal direction is minimized. During the injection process, the potting compound fills the first cavity in a manner similar to an upward flow through a vertical pipe, reducing disturbances and eddies during the flow of the compound and lowering the possibility of air bubbles being entrained inside the compound. Simultaneously, since both the first and second openings are located on the narrow sidewalls at the highest position, gas can directly reach the exhaust port in the vertical direction, facilitating the full discharge of gas without the need for vacuum or vibration equipment.

[0080] According to the potting and sealing method provided by the present invention, a settling step is set after potting is stopped, allowing residual air bubbles to rise along the gap between the circuit board and the inner wall of the housing under buoyancy, accumulating in the top area near the narrow sidewall. Since this area is pre-designed as a non-critical heat dissipation area without heat-generating components, the impact of air bubble accumulation on the overall heat dissipation performance of the inverter can be minimized. These accumulated air bubbles form microcavities after the potting compound cures, which act as buffer areas to absorb the volume increase caused by thermal expansion of the potting compound, reducing the possibility of component failure due to compression.

[0081] According to the inverter and its potting sealing method provided by the present invention, each gap in the shielding structure simultaneously serves as both electromagnetic shielding and potting channel, and the shielding component is embedded in the potting compound after curing, providing a double-sided heat conduction path. The same set of shielding structural features simultaneously achieves the functions of electromagnetic shielding, potting filling, and double-sided heat dissipation without the need for additional parts or processes.

[0082] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A potting and sealing method for an inverter, characterized in that, Includes the following steps: A housing is provided, the housing having a first cavity and a circuit board mounted in the first cavity, a gap between the circuit board and the inner wall of the housing, and a first opening and a second opening communicating with the first cavity on the smaller side wall of the housing. The housing is placed with the smaller sidewall facing upwards, so that both the first opening and the second opening are located in the top region of the first cavity; Using the first opening as the potting port and the second opening as the venting port, the potting compound is injected into the first cavity through the first opening, and the potting compound fills the first cavity from bottom to top, while the gas in the first cavity is discharged through the second opening. Stop filling the potting compound once it is full. The sealing components are respectively inserted into the first opening and the second opening, and a sealing fit is formed between the sealing components and the openings before the potting compound cures. After the potting compound cures, a seal is formed between the sealing element and the opening through the cured potting compound.

2. The potting and sealing method for an inverter as described in claim 1, characterized in that: After the glue is poured and before the fasteners are installed, a settling step is also included: the housing is held in the posture for a predetermined time, allowing residual air bubbles to rise along the gap between the circuit board and the inner wall of the first cavity under the action of buoyancy, and accumulate in the top area near the smaller side wall.

3. The potting and sealing method for an inverter as described in claim 2, characterized in that, The scheduled time is 1 to 5 minutes.

4. The potting and sealing method for an inverter as described in claim 1, characterized in that: The heat-generating components on the circuit board are concentrated in the middle area of ​​the circuit board, while there are no heat-generating components in the top area of ​​the first cavity corresponding to the side wall.

5. The potting and sealing method for an inverter as described in claim 1, characterized in that: Before the fasteners are installed, a potting compounding step is also included: potting compound is applied from the first opening and / or the second opening so that uncured potting compound adheres to the first opening and the second opening.

6. The potting and sealing method for an inverter as described in claim 1, characterized in that: The potting compound is a thermally conductive potting compound.

7. The potting and sealing method for an inverter as described in claim 1, characterized in that, The first opening and / or the second opening is a threaded hole, the sealing element is a threaded fastener, and the sealing fit is the potting compound filling the gap between the thread of the threaded fastener and the thread of the threaded hole.

8. The potting and sealing method for an inverter as described in claim 1, characterized in that: The housing includes a first housing and a second housing opposite to the first housing. A first shielding member is provided on the side of the first housing facing the second housing, and a second shielding member is provided on the side of the second housing facing the first housing. A first gap exists between the first shielding member and the second shielding member. The first housing, the second housing, the first shielding member, and the second shielding member enclose a second cavity. The area of ​​the circuit board to be shielded in the micro inverter extends into the second cavity through the first gap.

9. The potting and sealing method for an inverter as described in claim 8, characterized in that: The first shielding component has a second gap with the circuit board, and the second shielding component has a second gap with the circuit board; the potting compound flows into the second cavity through the second gap and / or the third gap, filling the area of ​​the second cavity located above and below the circuit board.

10. An inverter, characterized in that, include: The housing has a first cavity; A circuit board is installed in the first cavity, and there is a gap between the circuit board and the inner wall of the housing. The housing is provided with a first opening and a second opening that communicate with the first cavity. Encapsulating adhesive is used to fill the first cavity; The first fastener and the second fastener are respectively installed in the first opening and the second opening; There are glue-filling gaps between the first fastener and the first opening, and between the second fastener and the second opening. The glue-filling gaps are filled with cured potting compound to form a sealed structure. The area within the first cavity near the smaller sidewall has a bubble accumulation chamber.

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