Photovoltaic inverters and DC switches

Abstract

A photovoltaic inverter and a DC switch are disclosed. The photovoltaic inverter includes a DC switch and a DC-DC conversion circuit. The DC switch connects the photovoltaic string and the DC-DC conversion circuit. The DC switch includes multiple switch units stacked along a first direction, with a moving contact positioned between a first stationary contact and a second stationary contact along a second direction. An arc-extinguishing unit includes a first grid group and a third grid group arranged opposite each other along the second direction. The second grid group is positioned between the first and third grid groups. The first grid group contacts the first stationary contact and is located between the first stationary contact and the housing. The second grid group is located between the moving contact and the housing. The third grid group is located between the second stationary contact and the housing. The first grid group includes multiple first arc-extinguishing grids spaced apart along a third direction. The second grid group includes multiple second arc-extinguishing grids spaced apart and protruding towards the moving contact along the third direction. The third grid group includes multiple third arc-extinguishing grids spaced apart along the third direction.

Description

Technical Field

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

[0002] To reduce line losses and improve power generation efficiency, photovoltaic (PV) power generation systems commonly increase the voltage by increasing the number of PV strings. However, increasing the number of PV strings inevitably poses challenges to PV string protection, resulting in a severe challenge to the reliability of DC switches—a key component of PV inverters. DC switches typically use iron grids for arc extinguishing. The general arc extinguishing process involves four steps: arc generation, arc transfer, arc cutting, and final arc extinction. The arc transfer depends on factors such as current magnitude and the arrangement of the arc extinguishing chamber. When DC switches are used in high-voltage circuits, they must have the ability to extinguish arcs to reduce the hazards caused by arcing. Therefore, improving the arc extinguishing capability of DC switches has become an urgent problem to be solved. Utility Model Content

[0003] This application provides a photovoltaic inverter and a DC switch. The layout design of the arc extinguishing unit in the DC switch can effectively increase the number of arc extinguishing grids, further lengthen the arc extinguishing path, and improve the arc extinguishing capability of the DC switch.

[0004] In a first aspect, this application provides a photovoltaic inverter, which includes a DC switch and a DC-DC conversion circuit. The DC switch is used to connect a photovoltaic string and the DC-DC conversion circuit. The DC switch includes multiple switch units stacked along a first direction. Each switch unit includes a housing, a first stationary contact, a second stationary contact, a moving contact, and an arc-extinguishing unit. The housing is used to house the moving contact and the arc-extinguishing unit, and also partially houses the first and second stationary contacts. The moving contact is disposed between the first and second stationary contacts along a second direction. The moving contact is rotatable relative to the housing. When the moving contact is in contact with the first and second stationary contacts, the DC switch is turned on; when the moving contact is separated from the first and second stationary contacts, the DC switch is turned off. The arc-extinguishing unit includes a first grid group, a second grid group, and a third grid group. The first and third grid groups are arranged opposite each other along a second direction. The second grid group is located between the first and third grid groups. The first grid group contacts the first stationary contact and is located between the first stationary contact and the housing along a third direction. The second grid group is located between the moving contact and the housing along a third direction. The third grid group is located between the second stationary contact and the housing along a third direction. The first grid group includes multiple first arc-extinguishing grids arranged at intervals along a third direction. The second grid group includes multiple second arc-extinguishing grids arranged at intervals and protruding towards the moving contact along a third direction. The third grid group includes multiple third arc-extinguishing grids arranged at intervals along a third direction. The first, second, and third directions are perpendicular to each other.

[0005] In this application, the second grid group protrudes towards the moving contact along a third direction. That is, some of the second arc-extinguishing grids in the second grid group are closer to the moving contact in the third direction. This effectively increases the number of second arc-extinguishing grids in the space between the first and third grid groups, thereby further lengthening the arc-extinguishing path and improving the arc-extinguishing capability of the DC switch. In addition, the protrusion of the second grid group towards the moving contact can also serve to induce an arc, allowing some of the arc generated at the moving contact to be guided to the second grid group for arc extinguishing.

[0006] In conjunction with the first aspect, in one possible implementation, the second grid plate group includes a first arc-extinguishing portion and a second arc-extinguishing portion. The second arc-extinguishing portion is positioned between the first arc-extinguishing portion and the third grid plate group along a second direction. The first and second arc-extinguishing portions are located on opposite sides of the second arc-extinguishing grid plate closest to the moving contact in the second grid plate group. The line connecting the centers of the two second arc-extinguishing grid plates at the beginning and end of the second arc-extinguishing portion is a first straight line, and the line connecting the centers of the two third arc-extinguishing grid plates at the beginning and end of the third grid plate group is a second straight line. The angle formed by the second straight line and the first straight line is an acute angle.

[0007] In this design, the second arc-extinguishing grid closest to the moving contact in the second grid group is defined as follows: among multiple second arc-extinguishing grids, the one with the shortest distance to the moving contact in the third direction and the closest to the third grid group in the second direction. Multiple second arc-extinguishing grids along the second direction on the side facing the first grid group constitute the first arc-extinguishing portion. Multiple second arc-extinguishing grids along the second direction on the side facing the third grid group constitute the second arc-extinguishing portion. These second arc-extinguishing grids may be divided into the first arc-extinguishing portion, the second arc-extinguishing portion, or neither. The second arc-extinguishing grid located at the beginning of the second arc-extinguishing portion is the grid closest to the first arc-extinguishing portion in the second direction, and the second arc-extinguishing grid located at the end of the second arc-extinguishing portion is the grid closest to the third grid group in the second direction. The center line connecting these two second arc-extinguishing grids is a straight line. The third arc-extinguishing grid located at the first end of the third grid group is the grid closest to the second stationary contact in the third direction, while the third arc-extinguishing grid located at the last end of the third grid group is the grid furthest from the second stationary contact in the third direction. The center line connecting these two third arc-extinguishing grids is also a straight line. When the included angle between these two straight lines is an acute angle, the space between the second arc-extinguishing section and the third grid group is larger, which is beneficial for heat dissipation of the grids in the second arc-extinguishing section and the third grid group, reducing or avoiding the failure of the grids in this part, ensuring that the arc can be divided by all the grids in the arc-extinguishing unit, thereby improving the arc-extinguishing capability of the DC switch.

[0008] In conjunction with the first aspect, in one possible implementation, the shape of the second grid group projected onto the housing along the first direction is V-shaped.

[0009] In conjunction with the first aspect, in one possible implementation, the shape of the second grid group projected onto the housing along the first direction is U-shaped.

[0010] In conjunction with the first aspect, in one possible implementation, the orthogonal projection of the second grid group on the housing along the first direction is fan-shaped.

[0011] In conjunction with the first aspect, in one possible implementation, the shape of the second grid group projected onto the housing along the first direction is C-shaped.

[0012] Among the four implementation methods mentioned above, the shape of the orthogonal projection of the second grid group on the housing along the first direction includes V-shape, U-shape, fan shape and C-shape. For example, if the openings of the V-shape, U-shape, fan shape and C-shape are all facing the side of the second grid group away from the moving contact along the third direction, the space utilization between the first grid group and the third grid group can be improved. At the same time, more second arc-extinguishing grids can be arranged in this space. Without increasing the space size, the arc extinguishing path of the electric arc is extended, the arc extinguishing capability of the DC switch is improved, and it is also conducive to realizing the miniaturization design of the DC switch.

[0013] In conjunction with the first aspect, in one possible implementation, the switching unit further includes an arc-initiating element disposed between the moving contact and the arc-extinguishing unit. The arc-initiating element includes two insulating plates spaced apart and arranged opposite to each other along a first direction. The gap formed by the two insulating plates communicates with the gap between adjacent first arc-extinguishing grid plates in the first grid plate group.

[0014] The arc generated at the moving contact is guided to the first arc-extinguishing grid through the gap formed by the two insulating plates. This allows the arc to be extinguished sequentially from the first grid group to the second and third grid groups. The arc extinguishing path is consistent with the path formed by the first, second, and third grid groups, ensuring that the arc can be divided by all the grids in the arc-extinguishing unit, thus improving the arc extinguishing capability of the DC switch.

[0015] In conjunction with the first aspect, in one possible implementation, the switching unit further includes a first vent hole located in the housing. The first vent hole is used to connect the interior of the housing with the outside. Along the second direction, the first vent hole is closer to the third grid group than the first grid group.

[0016] Since the first arc-extinguishing grid in the first grid group is in contact with the first stationary contact, the electric arc is sequentially led from the first grid group to the second grid group and the third grid group. Therefore, the high-temperature gas at the first grid group is discharged to the outside through the first exhaust port along the gap between the second grid group and the housing. The high-temperature gas near the third grid group is closer to the first exhaust port and can be discharged to the outside through the first exhaust port more quickly, thereby improving heat dissipation efficiency and reducing the possibility of secondary arc generation.

[0017] In conjunction with the first aspect, in one possible implementation, the switching unit further includes a first guide plate, which is disposed between the arc extinguishing unit and the housing and blocks the first exhaust port.

[0018] There is a gap between the first guide plate and the side wall of the housing where the first exhaust port is located, so that the high-temperature gas from the first grid group, the second grid group and the third grid group can be discharged to the outside through the gap between the first guide plate and the side wall of the housing where the first exhaust port is located and through the first exhaust port. The first guide plate plays a guiding role, so that the high-temperature gas can be smoothly discharged to the outside through the first exhaust port. At the same time, the first guide plate can block the first exhaust port, which can reduce or avoid the phenomenon of electric arc spreading from the first exhaust port in the housing. It can also effectively block the molten metal slag, hot particles or ionized gas that may be generated during the arc extinguishing process, which is beneficial to improving the safety performance of the photovoltaic inverter.

[0019] In conjunction with the first aspect, in one possible implementation, the switching unit further includes a first flow-guiding bump, which is disposed between the second grid group and the housing along a third direction and located on the side of the second grid group away from the moving contact. The first flow-guiding bump and the first flow-guiding plate are arranged along a second direction. The first flow-guiding bump has a first flow-guiding surface, which is an inclined surface extending from one end of the first flow-guiding bump toward the second grid group to the other end of the first flow-guiding bump away from the second grid group.

[0020] The high-temperature gas around the second grid group can be guided along the first guide surface to the first exhaust port, thereby accelerating the heat dissipation efficiency.

[0021] In conjunction with the first aspect, in one possible implementation, the arc-extinguishing unit further includes a fourth grid group, a fifth grid group, and a sixth grid group. The fourth and sixth grid groups are arranged opposite to each other along a second direction. The fifth grid group is located between the fourth and sixth grid groups. A second stationary contact is provided between the fourth and third grid groups along a third direction. The fourth grid group contacts the second stationary contact and is located between the second stationary contact and the housing along a third direction. The fifth grid group is located between the moving contact and the housing along a third direction. A moving contact is provided between the fifth and second grid groups along a third direction. The sixth grid group is located between the first stationary contact and the housing along a third direction. A first stationary contact is provided between the sixth grid group and the first grid group. The fourth grid group includes multiple fourth arc-extinguishing grids arranged at intervals along a third direction. The fifth grid group includes multiple fifth arc-extinguishing grids arranged at intervals and protruding towards the moving contact along a third direction. The sixth grid group includes multiple sixth arc-extinguishing grids arranged at intervals along a third direction.

[0022] In this design, the fourth grid group contacts the second stationary contact. The arc generated at the second stationary contact and the moving contact can be extinguished along the arc-extinguishing path formed by the fourth, fifth, and sixth grid groups. Furthermore, the fifth grid group protrudes towards the moving contact along a third direction, allowing for more fifth arc-extinguishing grids to be placed in the space between the fourth and sixth grid groups, further lengthening the arc-extinguishing path and improving the arc-extinguishing capability of the DC switch. Additionally, the fourth, fifth, and sixth grid groups are located on one side of the moving contact along a third direction, while the first, second, and third grid groups are located on the other side. These three grid groups on both sides further extend the arc-extinguishing path, further enhancing the arc-extinguishing capability of the DC switch.

[0023] In conjunction with the first aspect, in one possible implementation, the fifth arc-extinguishing grid group includes a third arc-extinguishing portion and a fourth arc-extinguishing portion. The fourth arc-extinguishing portion is positioned between the third arc-extinguishing portion and the sixth arc-extinguishing grid group along the second direction. The third and fourth arc-extinguishing portions are located on opposite sides of the fifth arc-extinguishing grid group closest to the moving contact in the second direction. The center line connecting the two fifth arc-extinguishing grids at the beginning and end of the fourth arc-extinguishing portion is a third straight line, and the center line connecting the two sixth arc-extinguishing grids at the beginning and end of the sixth arc-extinguishing grid group is a fourth straight line. The angle formed by the fourth and third straight lines is an acute angle.

[0024] In this fifth arc-extinguishing grid group, the fifth arc-extinguishing grid closest to the moving contact is the one among the multiple fifth arc-extinguishing grids that is closest to the moving contact in the second direction. Multiple fifth arc-extinguishing grids along the second direction on the side facing the fourth grid group constitute the third arc-extinguishing portion. Multiple fifth arc-extinguishing grids along the second direction on the side facing the sixth grid group constitute the fourth arc-extinguishing portion. This fifth arc-extinguishing grid can be included in the third or fourth arc-extinguishing portion, or it can be excluded from either. The fifth arc-extinguishing grid located at the beginning of the fourth arc-extinguishing portion is the grid closest to the third arc-extinguishing portion in the second direction, and the fifth arc-extinguishing grid located at the end of the fourth arc-extinguishing portion is the grid closest to the sixth grid group in the second direction. The center line connecting these two fifth arc-extinguishing grids is a straight line. The sixth arc-extinguishing grid located at the first end of the sixth grid group is the grid closest to the first stationary contact in the third direction, and the sixth arc-extinguishing grid located at the last end of the sixth grid group is the grid furthest from the first stationary contact in the third direction. The center line connecting these two sixth arc-extinguishing grids is also a straight line. When the included angle formed by these two straight lines is an acute angle, the space between the fourth arc-extinguishing section and the sixth grid group is larger, which is beneficial for heat dissipation of the grids in the fourth arc-extinguishing section and the sixth grid group, reducing or avoiding the failure of the grids in this section, ensuring that the arc can be divided by all the grids in the arc-extinguishing unit, thereby improving the arc-extinguishing capability of the DC switch.

[0025] It should be noted that the fourth grid group corresponds to the first grid group, and the fourth grid group is in contact with the second stationary contact. The configuration and beneficial effects of the fourth grid group can be referenced from those of the first grid group. The fifth grid group corresponds to the second grid group, and the configuration and beneficial effects of the fifth grid group can be referenced from those of the second grid group. The sixth grid group corresponds to the third grid group, and the configuration and beneficial effects of the sixth grid group can be referenced from those of the third grid group.

[0026] In conjunction with the first aspect, in one possible implementation, the photovoltaic inverter further includes a circuit board with a DC-DC conversion circuit. The switching unit also includes a fixing part located in the housing, connected to the circuit board, and positioned along the second direction on the side of the sixth grid group away from the fourth grid group. The switching unit also includes a second vent, located in the housing, for connecting the interior of the housing to the outside. Along the second direction, the second vent is closer to the fourth grid group than the sixth grid group.

[0027] Since the DC switch is installed inside the photovoltaic inverter and the fixing part is located on the side of the sixth grid group away from the fourth grid group in the second direction, in order to facilitate the connection between the fixing part and the circuit board, the circuit board is usually also located on the side of the sixth grid group away from the fourth grid group in the second direction. Setting the second vent hole closer to the fourth grid group can reduce the impact of the high temperature gas discharged from the second vent hole on other components (such as capacitors and inductors) installed on the circuit board.

[0028] In conjunction with the first aspect, in one possible implementation, the switching unit further includes a third vent and a first partition. The third vent is located in the housing and connects the interior of the housing to the outside. Along the second direction, the third vent is further away from the sixth grid group than the second vent. The first partition is located along the second direction between the fourth grid group and the housing, and along the second direction, the first partition is closer to the third vent than the second vent.

[0029] The high-temperature gas generated by the fifth and sixth arc-extinguishing grid plates is lower than that generated by the fourth arc-extinguishing grid plate. Since the fourth grid plate group is closer to the two exhaust ports than the fifth and sixth grid plate groups, the high-temperature gas generated by the fourth arc-extinguishing grid plate is preferentially discharged to the outside through these two exhaust ports. If the first partition does not block part of the high-temperature gas generated by the fourth arc-extinguishing grid plate, the high-temperature gas generated by the fifth and sixth arc-extinguishing grid plates will easily remain inside the shell. In this application, the first partition is located between the fourth grid plate group and the housing along the second direction. An air passage is formed between the first partition and the side wall of the housing along the second direction, and another air passage is formed between the first partition and the fourth grid plate group along the second direction. Since the first partition is closer to the third exhaust port relative to the second exhaust port along the second direction, the high-temperature gas generated by the fourth arc-extinguishing grid plate is mainly discharged to the outside through these two air passages and the third exhaust port. Furthermore, the arrangement of the first partition can reduce the impact of the high-temperature gas generated by the fourth arc-extinguishing grid plate on the high-temperature gas generated by the fifth and sixth arc-extinguishing grid plates, so that the high-temperature gas generated by the fifth and sixth arc-extinguishing grid plates is mainly discharged to the outside through the second exhaust port. This can effectively shorten the time that the high-temperature gas generated by the fifth and sixth arc-extinguishing grid plates remains in the housing, which is beneficial to improving heat dissipation efficiency.

[0030] In conjunction with the first aspect, in one possible implementation, the switching unit further includes a second partition, which is disposed between the sixth grid group and the housing along a second direction; the distance between the second partition and the first stationary contact along a third direction is greater than the distance between the second partition and the housing along a third direction.

[0031] Along the second direction, an air passage is formed between the second partition and the housing, and another air passage is formed between the second partition and the sixth grid plate group. Multiple sixth arc-extinguishing grid plates located on the side of the second partition facing the first stationary contact along the third direction are discharged to the outside through one air passage, while the remaining sixth arc-extinguishing grid plates are mainly discharged to the outside through another air passage, so as to divert the high-temperature gas generated when the sixth grid plate group extinguishes the arc, shorten the time that part of the high-temperature gas stays in the housing, and help improve the heat dissipation efficiency.

[0032] Secondly, this application provides a DC switch, which is applied in a photovoltaic inverter provided in this application. The photovoltaic inverter includes a DC switch and a DC-DC conversion circuit. The DC switch is used to connect the photovoltaic string and the DC-DC conversion circuit. The DC switch includes multiple switch units stacked along a first direction. Each switch unit includes a housing, a first stationary contact, a second stationary contact, a moving contact, and an arc-extinguishing unit. The housing is used to house the moving contact and the arc-extinguishing unit, and also partially houses the first and second stationary contacts. The moving contact is disposed between the first and second stationary contacts along a second direction. The moving contact can rotate relative to the housing. When the moving contact is in contact with the first and second stationary contacts, the DC switch is turned on. When the moving contact is separated from the first and second stationary contacts, the DC switch is turned off. The arc-extinguishing unit includes a first grid group, a second grid group, and a third grid group. The first and third grid groups are arranged opposite each other along a second direction. The second grid group is located between the first and third grid groups. The first grid group contacts the first stationary contact and is located between the first stationary contact and the housing along a third direction. The second grid group is located between the moving contact and the housing along a third direction. The third grid group is located between the second stationary contact and the housing along a third direction. The first grid group includes multiple first arc-extinguishing grids arranged at intervals along a third direction. The second grid group includes multiple second arc-extinguishing grids arranged at intervals and protruding towards the moving contact along a third direction. The third grid group includes multiple third arc-extinguishing grids arranged at intervals along a third direction. The first, second, and third directions are perpendicular to each other.

[0033] It should be understood that the main body of the second aspect is a DC switch, and the specific content of the second aspect corresponds to the content of the DC switch in the first aspect. The corresponding features and effects of the second aspect can be referred to the description of the first aspect. To avoid repetition, detailed descriptions are omitted here. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0035] Figure 1 A schematic diagram of a photovoltaic power supply system;

[0036] Figure 2This is a simplified structural diagram of a photovoltaic inverter provided in one embodiment of this application;

[0037] Figure 3 This is a schematic diagram of the structure of a DC switch provided in one embodiment of this application;

[0038] Figure 4 This is a partial structural schematic diagram of a switching unit provided in one embodiment of this application;

[0039] Figure 5 This is a schematic diagram of the arrangement of the first grid group, the second grid group, and the third grid group provided in an embodiment of this application;

[0040] Figure 6 This is a partial structural schematic diagram of another switching unit provided in an embodiment of this application;

[0041] Figure 7 This is a partial structural schematic diagram of another switching unit provided in an embodiment of this application;

[0042] Figure 8 This is a schematic diagram of the arrangement of a second grid group according to an embodiment of this application;

[0043] Figure 9 This is a schematic diagram of another arrangement of the second grid group provided in an embodiment of this application;

[0044] Figure 10 This is a schematic diagram of the arrangement of another second grid group provided in an embodiment of this application;

[0045] Figure 11 This is a schematic diagram of the arrangement of another second grid group provided in an embodiment of this application;

[0046] Figure 12 This is a schematic diagram of the structure of a switching unit provided in one embodiment of this application;

[0047] Figure 13 This is a schematic diagram of the arrangement of the fifth grid group in one embodiment of this application;

[0048] Figure 14 for Figure 12 The diagram shows the exploded structure of the switch unit.

[0049] Figure 15 A schematic diagram of the heat dissipation path of a switching unit provided in an embodiment of this application;

[0050] Figure 16 A schematic diagram of another heat dissipation path for a switching unit provided in an embodiment of this application;

[0051] Figure 17This is a schematic diagram of the heat dissipation path of another switching unit provided in an embodiment of this application.

[0052] Explanation of reference numerals in the attached figures:

[0053] X - First direction; Y - Second direction; Z - Third direction; 10 - Handle; 20 - Operating mechanism; 30 - Switch unit; 31 - Housing; 311 - First vent; 312 - Second vent; 313 - Third vent; 314 - Fourth vent; 32a - First stationary contact; 32b - Second stationary contact; 33 - Moving contact; 34 - Fixing part; 35 - Connecting part; 36 - Arc extinguishing unit; 361 - First grid plate group; 3611 - First arc extinguishing grid plate; 362 - Second grid plate group; 3621 - Second arc extinguishing grid plate; 3622 - First arc extinguishing part; 3623 - Second arc extinguishing part; 363 - Third grid plate group; 3631 - Third arc extinguishing grid plate; 364 - Fourth grid plate group; 3641 - ... Four arc-extinguishing grid plates; 365-Fifth grid plate group; 3651-Fifth arc-extinguishing grid plate; 3652-Third arc-extinguishing section; 3653-Fourth arc-extinguishing section; 366-Sixth grid plate group; 3661-Sixth arc-extinguishing grid plate; 37-Arc-initiating component; 371-Insulating plate; 372-Transfer section; 38a-First guide plate; 38b-Second guide plate; 39a-First guide protrusion; 39b-Second guide protrusion; 391-First guide surface; 392-Second guide surface; 40-First partition; 41-Second partition; 42-Third partition; 43-Fourth partition; 100-DC switch; 200-Controller; 300-Circuit board; 400-Housing shell; 1000-Photovoltaic inverter; 2000-Photovoltaic module. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0055] Please see Figure 1 , Figure 1This is a schematic diagram of a photovoltaic (PV) power supply system. The PV power supply system includes a PV inverter 1000 and PV modules 2000. The PV inverter 1000 converts the direct current (DC) power from the PV modules 2000 into alternating current (AC) power and transmits the AC power to the grid or a load (not shown). Specifically, the PV inverter 1000 includes multiple DC terminals, a DC switch 100, a DC / DC circuit, DC buses BUS+ and BUS-, a DC / AC circuit, a grid-connected switch, and a controller 200. The DC / DC circuit and the DC / AC circuit can be collectively referred to as a DC-DC conversion circuit. The DC switch 100 is used to connect the PV strings and the DC-DC conversion circuit. In practical applications, the photovoltaic module 2000 is connected to the DC terminal, which then transmits DC power to the DC / DC circuit via the DC switch 100. The DC / DC circuit transforms the DC power and transmits it to the DC / AC circuit via the DC bus. Subsequently, the DC / AC circuit converts the DC power into AC power and transmits it to the grid or load via the grid-connected switch. Furthermore, the DC switch 100 includes multiple switching units and a trip unit. One end of each switching unit is used to connect to one or more parallel photovoltaic strings, where each photovoltaic string includes multiple photovoltaic modules 2000 connected in series. The other end of each switching unit is used to connect to the DC / DC circuit. The trip unit receives a trip signal from the controller 200, and thus, when the current flowing through the switching unit is abnormal, it promptly trips the DC switch 100 to eliminate the fault. For example, when the current flowing through at least one switching unit of the DC switch 100 exceeds a set threshold, or when the current flowing through at least one switching unit of the DC switch 100 is a reverse current, the controller 200 sends a trip signal to the trip unit, thereby causing the trip unit to release the corresponding linkage structure in a timely manner, achieving reliable disconnection of the aforementioned at least one switching unit. In practical applications, due to the linkage setting of multiple switching units, multiple switching units generally close or open simultaneously. It is worth mentioning that when the photovoltaic power supply system is working normally, the current between the photovoltaic string and the photovoltaic inverter 1000 is a forward current, and the direction of the forward current is from the photovoltaic module 2000 to the DC / DC circuit. When the photovoltaic string is reverse-connected or a short-circuit fault occurs in the photovoltaic string, a reverse current will appear in the photovoltaic power supply system. The direction of the reverse current is from the DC / DC circuit to the photovoltaic panel, or from other photovoltaic strings connected in parallel with the reverse-connected or short-circuited photovoltaic string to the reverse-connected or short-circuited photovoltaic string.For example, when the positive terminal of the photovoltaic string is connected to the negative terminal of the DC terminal and the negative terminal of the photovoltaic string is connected to the positive terminal of the DC terminal, i.e. when the photovoltaic string is reverse-connected, or when one photovoltaic string is short-circuited, the equivalent impedance of either of the two types of photovoltaic strings will be much lower than the equivalent impedance of the photovoltaic inverter 1000. Therefore, the current of other photovoltaic strings connected in parallel with the two types of photovoltaic strings will be directly injected into the two types of photovoltaic strings. At this time, the current on the switching unit connected to either of the two types of photovoltaic strings is the reverse current.

[0056] Please see Figure 2 , Figure 2 This is a simplified structural diagram of a photovoltaic inverter 1000 provided in one embodiment of this application. A circuit board 300 and a controller 200 fixed to the circuit board 300 are housed within a housing space enclosed by a housing 400. A DC switch 100 is also fixed to the circuit board 300 and partially housed within the housing 400. Specifically, the DC switch 100 includes a handle 10, an operating mechanism 20, and multiple switching units 30. The handle 10 protrudes from the housing 400, while the operating mechanism 20 and the multiple switching units 30 are located within the housing 400. In practical applications, the user can rotate the handle 10 to actuate the linkage mechanism included in the operating mechanism 20, thereby driving the multiple switching units 30 to close or open.

[0057] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a DC switch 100 provided in an embodiment of this application. Figure 3 In the middle, the handle 10, the operating mechanism 20 and multiple switch units 30 are stacked sequentially along the first direction X.

[0058] Please see Figure 4 , Figure 4 This is a partial structural schematic diagram of a switching unit 30 provided in one embodiment of this application. Figure 4 As shown, each switch unit 30 includes a housing 31, a first stationary contact 32a, a second stationary contact 32b, a moving contact 33, a fixing part 34, a connecting part 35, and an arc-extinguishing unit 36. The housing 31 houses the moving contact 33 and the arc-extinguishing unit 36, and partially houses the first and second stationary contacts 32a and 32b. The housing 31 also serves to mount the fixing part 34 and the connecting part 35. The moving contact 33 is disposed between the first and second stationary contacts 32a and 32b along a second direction Y. The moving contact 33 is rotatable relative to the housing 31. When the moving contact 33 contacts the first and second stationary contacts 32a and 32b, the DC switch 100 is turned on; when the moving contact 33 separates from the first and second stationary contacts 32a and 32b, the DC switch 100 is turned off.

[0059] Specifically, the moving contact 33 is shaped like a "Z" and includes multiple stacked metal sheets. Each of the two ends of the moving contact 33 extending in opposite directions includes a latch. During manual closing, the rotating handle 10 drives the moving contact 33 to rotate via the operating mechanism 20. When the moving contact 33 rotates to a suitable angle (e.g., 90°), both ends of the moving contact 33 clamp the first stationary contact 32a and the second stationary contact 32b through the latches, thus achieving conductive contact between the moving contact 33 and the two stationary contacts. In practical applications, one end of the fixing part 34 is connected to the first stationary contact 32a, and the other end of the fixing part 34 is conductively connected to the circuit board. The connecting part 35 is used to connect the photovoltaic module and the second stationary contact 32b. Therefore, when the connecting part 35 is connected to the photovoltaic module, rotating the handle 10 controls the conductive connection or disconnection between the photovoltaic module and the photovoltaic inverter.

[0060] Please combine them together Figure 5 , Figure 5 This is a schematic diagram illustrating the arrangement of a first grid group 361, a second grid group 362, and a third grid group 363 according to an embodiment of this application. The arc-extinguishing unit 36 ​​includes a first grid group 361, a second grid group 362, and a third grid group 363. The first grid group 361 and the third grid group 363 are arranged opposite each other along a second direction Y. The second grid group 362 is disposed between the first grid group 361 and the third grid group 363. The first grid group 361 is in contact with the first stationary contact 32a and is located between the first stationary contact 32a and the housing 31 along a third direction Z. The second grid group 362 is located between the moving contact 33 and the housing 31 along a third direction Z. The third grid group 363 is located between the second stationary contact 32b and the housing 31 along a third direction Z. The first grid group 361 includes a plurality of first arc-extinguishing grids 3611 spaced apart along the third direction Z. The second grid group 362 includes a plurality of second arc-extinguishing grids 3621 spaced apart, and the second grid group 362 protrudes towards the moving contact 33 along the third direction Z, that is, some of the second arc-extinguishing grids 3621 in the second grid group 362 are closer to the moving contact 33. The third grid group 363 includes a plurality of third arc-extinguishing grids 3631 spaced apart along the third direction Z. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0061] The second grid group 362 protrudes from the middle of its portion in the second direction Y toward the moving contact 33. For example, a portion of the second arc-extinguishing grid 3621 located in the middle of the second grid group 362 in the second direction Y protrudes toward the moving contact 33. This effectively increases the number of second arc-extinguishing grids 3621 in the space between the second arc-extinguishing grid 3621 protruding in the second direction Y and the first grid group 361, as well as between the second arc-extinguishing grid 3621 protruding in the second direction Y and the third grid group 363. This further lengthens the arc-extinguishing path and enhances the arc-extinguishing capability of the DC switch 100. Additionally, the protrusion of the second grid group 362 toward the moving contact 33 also serves to initiate an arc, allowing a portion of the arc generated at the moving contact 33 to be directed to the second grid group 362 for arc extinguishing.

[0062] To better understand the special configuration of the arc-extinguishing unit 36 ​​in this application and its beneficial effects, the implementation principle of the grid-based arc extinguishing will be described in detail below. As mentioned above, when the moving contact 33 cuts off the connection between the first stationary contact 32a and the second stationary contact 32b and generates an arc, the arc will enter the arc-extinguishing unit 36 ​​under the action of electrodynamic force. Since the arc-extinguishing unit 36 ​​includes multiple grids arranged at intervals (including the first arc-extinguishing grid 3611, the second arc-extinguishing grid 3621, and the third arc-extinguishing grid 3631), the arc will be cut into several segments and eventually extinguished. Specifically, when the arc enters the arc-extinguishing unit 36, each grid becomes an electrode, and there is a voltage drop between two adjacent grids, that is, two adjacent grids are equivalent to a battery. Therefore, the arc-extinguishing unit 36 ​​can be equivalent to a battery cluster formed by multiple batteries connected in series. When the total voltage drop that the multiple grids arranged at intervals can withstand is greater than the arc voltage of the arc, that is, when all the batteries in the battery cluster are working and the voltage corresponding to the battery cluster is greater than the arc voltage of the arc, the arc will be extinguished. It is worth mentioning that when the thickness of the grid plates in the arc-extinguishing unit 36 ​​and the spacing between two adjacent grid plates are determined, the more grid plates in the arc-extinguishing unit 36, the more batteries are in the aforementioned battery cluster, and the stronger the arc-extinguishing capability of the arc-extinguishing unit 36. Based on this, this application can effectively increase the number of grid plates in the housing 31 by making a special spatial arrangement of the first grid plate group 361, the second grid plate group 362, and the third grid plate group 363, thereby effectively improving the arc-extinguishing capability of the arc-extinguishing unit 36.

[0063] The arrangement direction of the multiple first arc-extinguishing grid plates 3611 can be approximately parallel to the third direction Z, for example, as shown in the figure. Figure 5 As shown, the center line connecting the multiple first arc-extinguishing grid plates 3611 is a curve; for example, as... Figure 6 As shown, Figure 6This is a partial structural diagram of another switching unit 30 provided in one embodiment of this application. The center line connecting the plurality of first arc-extinguishing grid plates 3611 is an arc. In this way, compared with the plurality of first arc-extinguishing grid plates 3611 arranged in a straight line, the arc-extinguishing path can be effectively extended, thereby improving the arc-extinguishing capability of the DC switch 100. Furthermore, when the center line connecting the plurality of first arc-extinguishing grid plates 3611 is an arc, and the first grid plate group 361 protrudes towards the third grid plate group 363 along the second direction Y, the gap between the first grid plate group 361 and the housing 31 along the second direction Y can be effectively increased, increasing the heat dissipation space and improving the heat dissipation effect.

[0064] In other embodiments, the arrangement direction of the plurality of first arc-quenching grids 3611 can be completely parallel to the third direction Z, for example, as shown in the figure. Figure 7 As shown, Figure 7 This is a partial structural diagram of another switching unit 30 provided in an embodiment of this application. The center line connecting the multiple first arc-extinguishing grid plates 3611 is parallel to the third direction Z. The first arc-extinguishing grid plate 3611 closest to the first stationary contact 32a on the third direction Z can contact the first stationary contact 32a through an arc-inducing plate, or the first arc-extinguishing grid plate 3611 closest to the first stationary contact 32a on the third direction Z can directly contact the first stationary contact 32a, so that the arc is led from the multiple first arc-extinguishing grid plates 3611 to the multiple second arc-extinguishing grid plates 3621 and the multiple third arc-extinguishing grid plates 3631, ensuring that the arc extinguishing path of the arc is consistent with the path formed by the first grid plate group 361, the second grid plate group 362, and the third grid plate group 363.

[0065] like Figure 5 As shown, in one embodiment, the arrangement direction of the plurality of second arc-extinguishing grids 3621 can be approximately parallel to the second direction Y. The portion of the second arc-extinguishing grids 3621 located in the middle of the second direction Y is closer to the moving contact 33 than the other second arc-extinguishing grids 3621. Thus, a small corner is formed between the second grid group 362 and the third grid group 363, which can extend the arc-extinguishing path of the electric arc.

[0066] Please see Figure 7 and Figure 8 , Figure 8 This application provides a schematic diagram of the arrangement of a second grid group 362 according to an embodiment of the present application. Along the first direction X ( Figure 4 (As shown) The orthographic projection of the second grid group 362 onto the housing 31 is V-shaped. Specifically, the orthographic projection of the second grid group 362 onto the housing 31 along the first direction X can be approximately V-shaped, such as... Figure 8 As shown, some of the second arc-extinguishing grids 3621 in the second grid group 362 are arranged in a direction parallel to the second direction Y, and these second arc-extinguishing grids 3621 are closest to the moving contact 33 in the third direction Z.

[0067] Please see Figure 9 , Figure 9 This is a schematic diagram illustrating another arrangement of the second grid group 362 provided in an embodiment of this application. (See attached diagram.) Figure 9 As shown, the orthographic projection of the second arc-extinguishing grid group 362 along the first direction X onto the housing 31 is U-shaped. Multiple second arc-extinguishing grids 3621 in the middle of the second direction Y are arranged in an arc shape, while the other second arc-extinguishing grids 3621 are arranged in a straight line, forming an overall U-shaped distribution.

[0068] The orthographic projection of the second grid group 362 along the first direction X onto the housing 31 is fan-shaped. For example, as... Figure 10 As shown, Figure 10 This is a schematic diagram of another arrangement of the second grid group 362 provided in an embodiment of this application. The orthographic projection of the second grid group 362 on the housing 31 along the first direction X is a semicircle. Alternatively, the orthographic projection of the second grid group 362 on the housing 31 along the first direction X may be a third-circle or a quarter-circle. Compared to the second grid group 362 being arranged in a straight line, this extends the arc extinguishing path, which is beneficial for improving the arc extinguishing capability of the DC switch 100.

[0069] Please see Figure 6 and Figure 11 , Figure 11 This is a schematic diagram of the arrangement of another second grid group 362 provided in an embodiment of this application. The shape of the orthographic projection of the second grid group 362 on the housing 31 along the first direction X is C-shaped.

[0070] In summary, the orthographic projection of the second grid group 362 on the housing 31 along the first direction X includes V-shape, U-shape, fan shape and C-shape. The openings of the V-shape, U-shape, fan shape and C-shape are all facing the side of the second grid group 362 away from the moving contact 33 along the third direction Z. This improves the space utilization between the first grid group 361 and the third grid group 363, and at the same time, more second arc-extinguishing grids 3621 can be arranged in this space. Without increasing the space size, the arc extinguishing path of the electric arc is extended, the arc extinguishing capability of the DC switch 100 is improved, and it is also conducive to realizing the miniaturization design of the DC switch 100.

[0071] The arrangement direction of the multiple third arc-extinguishing grid plates 3631 can be approximately parallel to the third direction Z, for example, as shown in the figure. Figure 5 As shown, the center line connecting the multiple third arc-extinguishing grid plates 3631 is a curve. For example, as shown... Figure 6As shown, the center line connecting the multiple third arc-extinguishing grid plates 3631 is an arc. This effectively extends the arc-extinguishing path compared to a linear arrangement of the third arc-extinguishing grid plates 3631, thereby improving the arc-extinguishing capability of the DC switch 100. When the center line connecting the multiple third arc-extinguishing grid plates 3631 is an arc, and the third grid plate group 363 protrudes towards the first grid plate group 361 along the second direction Y, the gap between the third grid plate group 363 and the housing 31 along the second direction Y is effectively increased, increasing the heat dissipation space and improving the heat dissipation effect.

[0072] In other embodiments, the plurality of third arc-quenching grids 3631 may be completely parallel to the third direction Z, for example, as Figure 7 As shown, the center line connecting the multiple third arc-extinguishing grid plates 3631 is parallel to the third direction Z.

[0073] For example, in the third grid group 363, the third arc-extinguishing grid 3631, which is closest to the second stationary contact 32b in the third direction Z, is spaced apart from the second stationary contact 32b.

[0074] The angle formed by the edge of the third grid group 363 towards the first grid group 361 along the second direction Y and the edge of the second grid group 362 towards the third grid group 363 along the second direction Y is an acute angle, and the opening of the included angle faces the moving contact 33.

[0075] Wherein, when the arrangement direction of the plurality of second arc-extinguishing grid plates 3621 is approximately parallel to the second direction Y, the edge of the second grid plate group 362 towards the third grid plate group 363 along the second direction Y refers to: the outer contour formed by the end of the plurality of second arc-extinguishing grid plates 3621 in the second grid plate group 362 closest to the moving contact 33 along the second direction Y, such as Figure 5 As shown by the thick dashed line L1. When the orthographic projection shape of the second grid group 362 on the housing 31 along the first direction X is V-shaped, U-shaped, fan-shaped, or C-shaped, the second grid group 362 encloses a space with an opening. The edge of the second grid group 362 towards the third grid group 363 along the second direction Y refers to the outer contour formed by the end of the plurality of second arc-extinguishing grids 3621 in the second grid group 362 closest to the moving contact 33 along the second direction Y. Figures 6 to 10 The thick dashed line L1 is shown in the figure. For ease of description, the edge of the second grid group 362 toward the third grid group 363 along the second direction Y is denoted as the edge L1 of the second grid group 362.

[0076] The edge of the third grating group 363 towards the first grating group 361 along the second direction Y refers to the outer contour formed by the multiple third arc-quenching gratings 3631 along the second direction Y at the end closest to the first grating group 361. Figures 5 to 10The thick dashed line L2 is shown in the figure. For ease of description, the edge of the third grid group 363 toward the first grid group 361 along the second direction Y is denoted as the edge L2 of the third grid group 363.

[0077] The angle formed by the edge L2 of the third grid group 363 and the edge L1 of the second grid group 362 is an acute angle, thus making the gap formed by the edge L1 of the second grid group 362 and the edge L2 of the third grid group 363 in the second direction Y (this gap is as follows) Figures 5 to 10 The area indicated by arrow S1 is larger, which is beneficial for heat dissipation of the second grid group 362 and the third grid group 363, reduces or avoids grid failure in the second grid group 362 and the third grid group 363, and ensures that the arc can be divided by all grids in the arc extinguishing unit 36, thereby improving the arc extinguishing capability of the DC switch 100.

[0078] It should be noted that when both the edge L1 of the second grid group 362 and the edge L2 of the third grid group 363 are curved, the included angle formed by them is the edge turning area or transition area. The included angle is the angle formed by the tangent of the edge L1 of the second grid group 362 and the tangent of the edge L2 of the third grid group 363. Figure 6 The angle α1 shown has different tangent directions for the two. When the edge L1 of the second grid group 362 and the edge L2 of the third grid group 363 are straight lines, the included angle formed by them is the angle between the two straight lines, such as... Figure 7 Angle α2 is shown. When the edge L1 of the second grid group 362 is a curve and the edge L2 of the third grid group 363 is a straight line, the included angle formed by the two is the edge turning area or turning area. The included angle formed by the two is the angle formed by the tangent of edge L1 and edge L2, as shown. Figure 9 The angle α3 shown and Figure 10 Angle α4 is shown. It is worth mentioning that when the edge L1 of the second grid group 362 is a curve and the edge L2 of the third grid group 363 is a straight line, along the second direction Y, the angle formed by the tangent line formed by the end of any of the second arc-extinguishing grids 3621 in the second grid group 362 that faces the third grid group 363 closest to the moving contact 33 and the edge L2 of the third grid group 363 is an acute angle.

[0079] Please combine Figure 11The second grid group 362 includes a first arc-extinguishing portion 3622 and a second arc-extinguishing portion 3623. Along the second direction Y, the second arc-extinguishing portion 3623 is disposed between the first arc-extinguishing portion 3622 and the third grid group 363. The first arc-extinguishing portion 3622 and the second arc-extinguishing portion 3623 are located on opposite sides of the second arc-extinguishing grid 3621 closest to the moving contact 33 in the second grid group 362. The second arc-extinguishing grid 3621 closest to the moving contact 33 in the second grid group 362 is the one among the plurality of second arc-extinguishing grids 3621 with the shortest distance to the moving contact 33 in the third direction Z. The arc-extinguishing grid 3621 closest to the third grid group 363 along the second direction Y, along the second direction Y, comprises a plurality of second arc-extinguishing grids 3621 on the side facing the first grid group 361, constituting a first arc-extinguishing portion 3622. A plurality of second arc-extinguishing grids 3621 on the side facing the third grid group 363 along the second direction Y constitute a second arc-extinguishing portion 3623. The second arc-extinguishing grids 3621 may be divided into the first arc-extinguishing portion 3622 or the second arc-extinguishing portion 3623, or may not be divided into either the first arc-extinguishing portion 3622 or the second arc-extinguishing portion 3623. For example, as... Figure 8 As shown, there are six second arc-extinguishing grid plates 3621 closest to the moving contact 33 in the third direction Z. These six second arc-extinguishing grid plates 3621 are closest to the third grid plate group 363 in the second direction Y. The sixth second arc-extinguishing grid plate 3621 from the left in the figure is used as the dividing grid plate. The multiple second arc-extinguishing grid plates 3621 on the side of the second arc-extinguishing grid plate 3621 facing the first grid plate group 361 in the second direction Y are called the first arc-extinguishing part 3622. The multiple second arc-extinguishing grid plates 3621 on the side of the second arc-extinguishing grid plate 3621 facing the third grid plate group 363 in the second direction Y are called the second arc-extinguishing part 3623. The first arc-extinguishing part 3622 and the second arc-extinguishing part 3623 do not include the second arc-extinguishing grid plate 3621.

[0080] The center line connecting the two second arc-extinguishing grid plates 3621 located at the beginning and end of the second arc-extinguishing section 3623 is the first straight line L3. Among them, the second arc-extinguishing grid plate 3621 located at the beginning of the second arc-extinguishing section 3623 is the grid plate of the second arc-extinguishing section 3623 that is closest to the first arc-extinguishing section 3622 in the second direction Y, and the second arc-extinguishing grid plate 3621 located at the end of the second arc-extinguishing section 3623 is the grid plate of the second arc-extinguishing section 3623 that is closest to the third grid plate group 363 in the second direction Y. The center line connecting these two second arc-extinguishing grid plates 3621 is a straight line. The center line connecting the two third arc-extinguishing grid plates 3631 located at the beginning and end of the third grid plate group 363 is the second straight line L4. Among them, the third arc-extinguishing grid plate 3631 located at the beginning of the third grid plate group 363 is the grid plate of the third grid plate group 363 that is closest to the second stationary contact 32b in the third direction Z, and the third arc-extinguishing grid plate 3631 located at the end of the third grid plate group 363 is the grid plate of the third grid plate group 363 that is furthest from the second stationary contact 32b in the third direction Z. The center line connecting these two third arc-extinguishing grid plates 3631 is also a straight line.

[0081] The angle formed by the second line L4 and the first line L3 is an acute angle, such as Figure 11 As shown, the angle formed by the second straight line L4 and the first straight line L3 is denoted as α5. This makes the space between the second arc-extinguishing part 3623 and the third grid plate group 363 larger, which is conducive to the heat dissipation of the grid plates in the second arc-extinguishing part 3623 and the third grid plate group 363, reduces or avoids the failure of the grid plates in this part, and ensures that the arc can be divided by all the grid plates in the arc-extinguishing unit 36, thereby improving the arc-extinguishing capability of the DC switch 100.

[0082] Please see Figure 12 , Figure 12This is a schematic diagram of the structure of a switch unit 30 provided in an embodiment of this application. Furthermore, the arc extinguishing unit 36 ​​also includes a fourth grid plate group 364, a fifth grid plate group 365, and a sixth grid plate group 366. The fourth grid plate group 364 and the sixth grid plate group 366 are arranged opposite each other along the second direction Y. The fifth grid plate group 365 is located between the fourth grid plate group 364 and the sixth grid plate group 366. A second stationary contact 32b is provided between the fourth grid plate group 364 and the third grid plate group 363 along the third direction Z. The fourth grid plate group 364 contacts the second stationary contact 32b and is located between the second stationary contact 32b and the housing 31 along the third direction Z. The fifth grid plate group 365 is located between the moving contact 33 and the housing 31 along the third direction Z. A moving contact 33 is provided between the fifth grid plate group 365 and the second grid plate group 362 along the third direction Z. The sixth grid plate group 366 is located between the first stationary contact 32a and the housing 31 along the third direction Z. A first stationary contact 32a is provided between the sixth grid plate group 366 and the first grid plate group 361. The fourth grid group 364 includes a plurality of fourth arc-extinguishing grids 3641 arranged at intervals along the third direction Z; the fifth grid group 365 includes a plurality of fifth arc-extinguishing grids 3651 arranged at intervals and the fifth grid group 365 protrudes towards the moving contact 33 along the third direction Z; and the sixth grid group 366 includes a plurality of sixth arc-extinguishing grids 3661 arranged at intervals along the third direction Z.

[0083] In this circuit, the fourth grid plate group 364 contacts the second stationary contact 32b. The electric arc generated at the second stationary contact 32b and the moving contact 33 can be extinguished along the arc extinguishing path formed by the fourth grid plate group 364, the fifth grid plate group 365, and the sixth grid plate group 366. Furthermore, the fifth grid plate group 365 protrudes towards the moving contact 33 along the third direction Z, allowing more fifth arc extinguishing grid plates 3651 to be installed in the space between the fourth grid plate group 364 and the sixth grid plate group 366, further lengthening the arc extinguishing path and improving the arc extinguishing capability of the DC switch 100. Furthermore, the fourth grid group 364, the fifth grid group 365, and the sixth grid group 366 are located on one side of the moving contact 33 along the third direction Z, while the first grid group 361, the second grid group 362, and the third grid group 363 are located on the other side of the moving contact 33 along the third direction Z. These three grid groups on both sides can further extend the arc-extinguishing path and further enhance the arc-extinguishing capability of the DC switch 100. Additionally, the fifth grid group 365 protrudes towards the moving contact 33 and can also serve to initiate an arc, allowing a portion of the arc generated at the moving contact 33 to be directed to the fifth grid group 365 for arc extinguishing.

[0084] The arrangement direction of the multiple fourth arc-extinguishing grid plates 3641 is the same as that of the multiple first arc-extinguishing grid plates 3611, the arrangement direction of the multiple fifth arc-extinguishing grid plates 3651 is the same as that of the multiple second arc-extinguishing grid plates 3621, and the arrangement direction of the multiple sixth arc-extinguishing grid plates 3661 is the same as that of the multiple third arc-extinguishing grid plates 3631, which will not be described in detail here.

[0085] In one embodiment, the shape of the orthographic projection of the fifth arc-extinguishing grid 3651 onto the housing 31 includes a V-shape, a U-shape, a fan shape, and a C-shape. The openings of the V-shape, U-shape, fan shape, and C-shape all face the side of the fifth grid group 365 that is away from the moving contact 33 along the third direction Z. This can improve the space utilization between the fourth grid group 364 and the sixth grid group 366, and at the same time, more fifth arc-extinguishing grids 3651 can be arranged in this space. Without increasing the space size, the arc extinguishing path of the electric arc is extended, the arc extinguishing capability of the DC switch 100 is improved, and it is also conducive to realizing the miniaturization design of the DC switch 100.

[0086] The angle formed by the edge of the sixth grid group 366 towards the fourth grid group 364 along the second direction Y and the edge of the fifth grid group 365 towards the sixth grid group 366 along the second direction Y is an acute angle.

[0087] The edge of the fifth grid group 365 along the second direction Y toward the sixth grid group 366 is defined the same as the edge of the second grid group 362 along the second direction Y toward the third grid group 363. Similarly, the edge of the sixth grid group 366 along the second direction Y toward the fourth grid group 364 is defined the same as the edge of the third grid group 363 along the second direction Y toward the first grid group 361. To avoid repetition, this will not be elaborated further. The angle formed by the aforementioned edge of the fifth grid group 365 and the edge of the sixth grid group 366 toward the fourth grid group 364 is an acute angle, resulting in a gap (such as...) formed between the aforementioned edges of the fifth grid group 365 and the aforementioned edges of the sixth grid group 366 in the second direction Y. Figure 12 The area indicated by the middle arrow S2 is larger, which is beneficial for heat dissipation of the fifth grid group 365 and the sixth grid group 366, reduces or avoids grid failure in the fifth grid group 365 and the sixth grid group 366, and ensures that the arc can be divided by all grids in the arc extinguishing unit 36, thereby improving the arc extinguishing capability of the DC switch 100.

[0088] Please see Figure 13 , Figure 13 This is a schematic diagram of the arrangement of the fifth grid group 365 in one embodiment of this application. The fifth grid group 365 includes a third arc-extinguishing portion 3652 and a fourth arc-extinguishing portion 3653. Along the second direction Y, the fourth arc-extinguishing portion 3653 is disposed between the third arc-extinguishing portion 3652 and the sixth grid group 366. The third arc-extinguishing portion 3652 and the fourth arc-extinguishing portion 3653 are located on opposite sides of the fifth arc-extinguishing grid 3651 closest to the moving contact 33 in the fifth grid group 365. The division of the third arc-extinguishing portion 3652 and the fourth arc-extinguishing portion 3653 in the fifth grid group 365 can be referred to the division of the first arc-extinguishing portion 3622 and the second arc-extinguishing portion 3623 in the second grid group 362. To avoid repetition, it will not be described again.

[0089] The center line connecting the two fifth arc-extinguishing grid plates 3651 located at the beginning and end of the fourth arc-extinguishing section 3653 is the third straight line L5. The center line connecting the two sixth arc-extinguishing grid plates 3661 located at the beginning and end of the sixth grid plate group 366 is the fourth straight line L6. The angle formed by the fourth straight line L6 and the third straight line L5 is an acute angle. Figure 13 As shown, the angle formed by the fourth line L6 and the third line L5 is denoted as α6.

[0090] A fifth arc-extinguishing grid plate 3651 located at the beginning of the fourth arc-extinguishing section 3653 is the grid plate closest to the third arc-extinguishing section 3652 in the second direction Y. A fifth arc-extinguishing grid plate 3651 located at the end of the fourth arc-extinguishing section 3653 is the grid plate closest to the sixth grid plate group 366 in the second direction Y. The center line connecting these two fifth arc-extinguishing grid plates 3651 is a straight line. A sixth arc-extinguishing grid plate 3661 located at the beginning of the sixth grid plate group 366 is the grid plate closest to the first stationary contact 32a in the third direction Z. A sixth arc-extinguishing grid plate 3661 located at the end of the sixth grid plate group 366 is the grid plate furthest from the first stationary contact 32a in the third direction Z. The center line connecting these two sixth arc-extinguishing grid plates 3661 is also a straight line. When the angle formed by these two straight lines is acute, the space between the fourth arc-extinguishing section 3653 and the sixth grid plate group 366 is larger, which is conducive to the heat dissipation of the first grid plate in the fourth arc-extinguishing section 3653 and the sixth grid plate group 366, reduces or avoids the failure of the grid plate in this part, and ensures that the arc can be divided by all the grid plates in the arc-extinguishing unit 36, thereby improving the arc-extinguishing capability of the DC switch 100.

[0091] Please combine Figure 12 and Figure 14 , Figure 14 for Figure 12 The diagram shows an exploded view of the switching unit 30. In one embodiment, the switching unit 30 further includes an arc-inducing element 37, which is disposed between the moving contact 33 and the arc-extinguishing unit 36. The arc-inducing element 37 is used to guide the electric arc to the arc-extinguishing unit 36. For example, an arc-inducing element 37 is provided between the second grid group 362 and the moving contact 33. This arc-inducing element 37 is used to guide the electric arc at the moving contact 33, the first stationary contact 32a, and the second stationary contact 32b to the first grid group 361, the second grid group 362, and the third grid group 363.

[0092] The arc-initiating element 37 includes two insulating plates 371 spaced apart and arranged opposite to each other along a first direction X. In one embodiment, the gap formed by the two insulating plates 371 communicates with the gap between adjacent first arc-extinguishing grid plates 3611 in the first grid plate group 361. The arc generated at the moving contact 33 is guided to the first arc-extinguishing grid plate 3611 through the gap formed by the two insulating plates 371, so that the arc can be sequentially guided from the first grid plate group 361 to the second grid plate group 362 and the third grid plate group 363 for arc extinguishing. This ensures that the arc extinguishing path is consistent with the path formed by the first grid plate group 361, the second grid plate group 362 and the third grid plate group 363, guaranteeing that the arc can be divided by all the grid plates in the arc extinguishing unit 36, thereby improving the arc extinguishing capability of the DC switch 100.

[0093] In another embodiment, the gap formed by the two insulating plates 371 is connected to the gap between adjacent first arc-extinguishing grid plates 3611 in the first grid plate group 361 and the gap between adjacent second arc-extinguishing grid plates 3621 in the second grid plate group 362. In this way, the electric arc can be directed to the second grid plate group 362 in addition to the first grid plate group 361.

[0094] In another embodiment, the gap formed by the two insulating plates 371 is connected to the gap between adjacent first arc-extinguishing grid plates 3611 in the first grid plate group 361 and the gap between adjacent third arc-extinguishing grid plates 3631 in the third grid plate group 363. In this way, the electric arc can be directed to the third grid plate group 363 in addition to the first grid plate group 361.

[0095] In another embodiment, the gap formed by the two insulating plates 371 is connected to the gap between adjacent first arc-extinguishing grid plates 3611 in the first grid plate group 361, the gap between adjacent second arc-extinguishing grid plates 3621 in the second grid plate group 362, and the gap between adjacent third arc-extinguishing grid plates 3631 in the third grid plate group 363. In this way, the electric arc can be guided to the first grid plate group 361, the second grid plate group 362, and the third grid plate group 363 through the gap formed by the two insulating plates 371.

[0096] The arc-starting component 37 may also include a transition portion 372, which is used to connect two insulating plates 371 and is located at the edge of the two insulating plates 371. The transition portion 372 is located between the third arc-extinguishing grid plate 3631 closest to the second stationary contact 32b in the third grid plate group 363 in the third direction Z and the second stationary contact 32b, so as not to affect the gap formed by the two insulating plates 371 and the gap between adjacent first arc-extinguishing grid plates 3611 in the first grid plate group 361, the gap between adjacent second arc-extinguishing grid plates 3621 in the second grid plate group 362, and the gap between adjacent third arc-extinguishing grid plates 3631 in the third grid plate group 363.

[0097] In an embodiment where the switching unit 30 includes a fourth grid group 364, a fifth grid group 365, and a sixth grid group 366, an arc-inducing element 37 is also provided between the fifth grid group 365 and the moving contact 33. This arc-inducing element 37 is used to guide the electric arc at the moving contact 33, the first stationary contact 32a, and the second stationary contact 32b to the fourth grid group 364, the fifth grid group 365, and the sixth grid group 366. The gap formed by the two insulating plates 371 of the arc-inducing element 37 is connected to the gap between adjacent fourth arc-extinguishing grids 3641 in the fourth grid group 364. The electric arc can be sequentially guided from the fourth grid group 364 to the fifth grid group 365 and the sixth grid group 366, ensuring that the electric arc can be divided by all the grids in the arc-extinguishing unit 36, thereby improving the arc-extinguishing capability of the DC switch 100. Based on this, at least one of the gaps between adjacent fifth arc-extinguishing grid plates 3651 in the fifth grid plate group 365 and between adjacent sixth arc-extinguishing grid plates 3661 in the sixth grid plate group 366 can also communicate with the gap formed by the two insulating plates 371 of the arc-initiating member 37. The transition portion 372 of the arc-initiating member 37 is located between the sixth arc-extinguishing grid plate 3661 closest to the first stationary contact 32a in the third direction Z of the sixth grid plate group 366 and the first stationary contact 32a.

[0098] In one embodiment, the switching unit 30 further includes a first vent 311, a first guide plate 38a, and a first guide protrusion 39a. The first vent 311 is disposed on the housing 31 and serves to connect the interior of the housing 31 with the outside. The first guide plate 38a is disposed between the arc-extinguishing unit 36 ​​and the housing 31 and blocks the first vent 311. The first guide protrusion 39a is disposed along the third direction Z between the second grid group 362 and the housing 31 and serves to guide the high-temperature gas around the second grid group 362 to the first vent 311.

[0099] Specifically, the first vent 311 penetrates the side wall of the housing 31. Along the second direction Y, the first vent 311 is closer to the third grid group 363 than the first grid group 361. For example, the first vent 311 is located on the center line of the second grid group 362 (which is parallel to the third direction Z) and biased towards the third grid group 363. Since one of the first arc-extinguishing grids 3611 in the first grid group 361 is in contact with the first stationary contact 32a, the electric arc is sequentially led from the first grid group 361 to the second grid group 362 and the third grid group 363. Therefore, the high-temperature gas at the first grid group 361 is discharged to the outside through the first vent 311 along the gap between the second grid group 362 and the housing 31. The high-temperature gas near the third grid group 363 is closer to the first vent 311 and can be discharged to the outside more quickly from the first vent 311, improving heat dissipation efficiency and reducing the possibility of secondary arc generation.

[0100] There is a gap between the first guide plate 38a and the side wall of the housing 31 where the first exhaust port 311 is located, so that the high-temperature gas from the first grid group 361, the second grid group 362 and the third grid group 363 can be discharged to the outside through the first exhaust port 311 through the gap between the first guide plate 38a and the side wall of the housing 31 where the first exhaust port 311 is located. The first guide plate 38a plays a guiding role, so that the high-temperature gas can be smoothly discharged to the outside through the first exhaust port 311. At the same time, the first guide plate 38a can block the first exhaust port 311, which can reduce or avoid the phenomenon of electric arc spreading from the first exhaust port 311 in the housing 31. It can also effectively block the metal slag, hot particles or ionized gas that may be generated during the arc extinguishing process, which is beneficial to improving the safety performance of the photovoltaic inverter.

[0101] The first guide bump 39a is located on the side of the second grid group 362 away from the moving contact 33 along the third direction Z. The first guide bump 39a and the first guide plate 38a are arranged along the second direction Y. The arrangement of the first guide bump 39a can divert the high-temperature gas near the second grid group 362, reducing the phenomenon of high-temperature gas stagnation in the space between the second grid group 362 and the housing 31. Specifically, the first guide bump 39a has a first guide surface 391, which is an inclined surface extending from one end of the first guide bump 39a toward the second grid group 362 to the other end of the first guide bump 39a away from the second grid group 362. This allows the high-temperature gas around the second grid group 362 to be guided along the first guide surface 391 to the first exhaust hole 311, thereby accelerating the heat dissipation efficiency.

[0102] The first guide bump 39a can be spindle-shaped. By adjusting the orientation of the spindle-shaped first guide bump 39a, high-temperature gas can be guided to pass smoothly, reducing or avoiding flow instability. There can be one or more first guide bumps 39a. Multiple first guide bumps 39a are disposed between the second grid plate group 362 and the housing 31 and are located on the side of the second grid plate group 362 away from the moving contact 33 along the third direction Z.

[0103] The number of first guide surfaces 391 can be two, for example, as shown below. Figure 13 As shown, the first guide protrusion 39a has a first guide surface 391 formed on both opposite sides. The high-temperature gas around the second grid plate group 362 can flow along the first guide surface 391 on both sides to the side wall of the housing 31 where the first exhaust hole 311 is located, and thus be discharged to the outside from the first exhaust hole 311.

[0104] When there is only one first guide bump 39a, the high-temperature gas generated by the second grid group 362 is guided to the outside from the first guide surface 391 on both sides of the first guide bump 39a.

[0105] There can be multiple first flow guiding bumps 39a, which are spaced apart on the side of the second grid group 362 away from the moving contact 33. The shape of the orthographic projection of each first flow guiding bump 39a in the housing 31 is different along the first direction X. The orthographic projections of two adjacent first flow guiding bumps 39a along the third direction Z overlap. For example, if there are two first flow guiding bumps 39a, the orthographic projection of one first flow guiding bump 39a along the third direction Z overlaps with the orthographic projection of the other first flow guiding bump 39a along the third direction Z, so that the space occupied by the multiple first flow guiding bumps 39a in the housing 31 is small. Moreover, the first flow guiding surface 391 of at least one of the multiple first flow guiding bumps 39a is inclined toward the first exhaust hole 311, so that the high-temperature gas around the second grid group 362 can flow smoothly through the two first flow guiding bumps 39a to the first exhaust hole 311.

[0106] In the embodiment where the arc-extinguishing unit 36 ​​includes a fourth grid group 364, a fifth grid group 365, and a sixth grid group 366, the switching unit 30 further includes a second vent 312, a second guide plate 38b, and a second guide protrusion 39b. The second vent 312 is located in the housing 31 and serves to connect the interior of the housing 31 with the outside. The second guide plate 38b is located between the arc-extinguishing unit 36 ​​and the housing 31 and blocks the second vent 312. The second guide protrusion 39b is located along the third direction Z between the fifth grid group 365 and the housing 31 and serves to guide the high-temperature gas around the fifth grid group 365 to the second vent 312.

[0107] The second vent 312 penetrates the side wall of the housing 31. Along the second direction Y, the second vent 312 is closer to the fourth grid group 364 relative to the sixth grid group 366. For example, the second vent 312 is located on the centerline of the fifth grid group 365 (which is parallel to the third direction Z) and is biased towards the fourth grid group 364. Please refer to... Figure 2 Since the DC switch 100 is installed inside the photovoltaic inverter 1000 and the fixing part 34 is located on the side of the sixth grid group 366 away from the fourth grid group 364 in the second direction Y, in order to facilitate the connection between the fixing part 34 and the circuit board 300, the circuit board 300 is usually also located on the side of the sixth grid group 366 away from the fourth grid group 364 in the second direction Y. By placing the second exhaust port 312 closer to the fourth grid group 364, the impact of the high temperature gas discharged from the second exhaust port 312 on other devices (such as capacitors, inductors, etc.) installed on the circuit board 300 can be reduced.

[0108] In one embodiment, the second exhaust port 312 is directly opposite the first exhaust port 311 in the third direction Z, and the second guide plate 38b and the first guide plate 38a are arranged opposite each other in the third direction Z, with a third grid group 363, a second stationary contact 32b and a fourth grid group 364 between them.

[0109] There is a gap between the second guide plate 38b and the side wall of the housing 31 where the second exhaust port 312 is located, so that the high-temperature gas from the fourth grid group 364, the fifth grid group 365 and the sixth grid group 366 can be discharged to the outside through the gap between the second guide plate 38b and the side wall of the housing 31 where the second exhaust port 312 is located and the second exhaust port 312. The second guide plate 38b plays a guiding role, so that the high-temperature gas can be smoothly discharged to the outside through the second exhaust port 312. At the same time, the second guide plate 38b can block the second exhaust port 312, which can reduce or avoid the phenomenon of electric arc spreading from the second exhaust port 312 in the housing 31. It can also effectively block the metal slag, hot particles or ionized gas that may be generated during the arc extinguishing process, which is beneficial to improving the safety performance of the photovoltaic inverter 1000.

[0110] The second guide protrusion 39b is disposed between the fifth grid group 365 and the housing 31 along the third direction Z. The second guide protrusion 39b and the second guide plate 38b are arranged along the second direction Y. The arrangement of the second guide protrusion 39b can divert the high-temperature gas near the fifth grid group 365 and reduce the phenomenon of high-temperature gas stagnating in the space between the fifth grid group 365 and the housing 31.

[0111] The structure of the second guide bump 39b can be the same as that of the first guide bump 39a. The second guide bump 39b has a second guide surface 392, which is an inclined surface extending from one end of the second guide bump 39b toward the fifth grid group 365 to the other end of the second guide bump 39b away from the fifth grid group 365. In this way, the high-temperature gas around the fifth grid group 365 can be guided along the second guide surface 392 to the second exhaust hole 312, thereby accelerating the heat dissipation efficiency.

[0112] When there are multiple second guide bumps 39b, the positional relationship between the multiple second guide bumps 39b can be referenced to the positional relationship between the multiple first guide bumps 39a. The difference is that the second guide surface 392 of at least one of the multiple second guide bumps 39b is inclined toward the second exhaust hole 312, so that the high temperature gas around the fifth grid group 365 can flow smoothly through the two second guide bumps 39b to the second exhaust hole 312.

[0113] Please see Figure 15 , Figure 15This is a schematic diagram of the heat dissipation path of a switching unit 30 according to an embodiment of this application. In an embodiment where the arc extinguishing unit 36 ​​includes a fourth grid group 364, a fifth grid group 365, and a sixth grid group 366, the switching unit 30 further includes a third vent 313 and a first partition 40. The third vent 313 is disposed on the housing 31 and located along the third direction Z on the side of the moving contact 33 away from the first vent 311. The third vent 313 connects the interior of the housing 31 to the outside. Along the second direction Y, the third vent 313 is further away from the sixth grid group 366 than the second vent 312. The first partition 40 is disposed along the second direction Y between the fourth grid group 364 and the housing 31. Along the second direction Y, the first partition 40 is closer to the third vent 313 than the second vent 312.

[0114] The high-temperature gas generated by the fifth arc-extinguishing grid 3651 and the sixth arc-extinguishing grid 3661 is lower than the high-temperature gas generated by the fourth arc-extinguishing grid 3641. Since the fourth grid group 364 is closer to the two exhaust holes than the fifth grid group 365 and the sixth grid group 366, the high-temperature gas generated by the fourth arc-extinguishing grid 3641 is preferentially discharged to the outside through the two exhaust holes. If the first partition 40 does not block part of the high-temperature gas generated by the fourth arc-extinguishing grid 3641, the high-temperature gas generated by the fifth arc-extinguishing grid 3651 and the sixth arc-extinguishing grid 3661 will easily remain in the housing 31. In this application, the first partition 40 is located between the fourth grid plate group 364 and the housing 31 along the second direction Y. An air passage is formed between the first partition 40 and the side wall of the housing 31 along the second direction Y, and another air passage is formed between the first partition 40 and the fourth grid plate group 364 along the second direction Y. Since the first partition 40 is closer to the third exhaust port 313 along the second direction Y than the second exhaust port 312, the high-temperature gas generated by the fourth arc-extinguishing grid plate 3641 is mainly discharged to the outside through these two air passages and the third exhaust port 313. The arrangement of the first partition 40 can reduce the impact of the high-temperature gas generated by the fourth arc-extinguishing grid plate 3641 on the high-temperature gas generated by the fifth arc-extinguishing grid plate 3651 and the sixth arc-extinguishing grid plate 3661, so that the high-temperature gas generated by the fifth arc-extinguishing grid plate 3651 and the sixth arc-extinguishing grid plate 3661 is mainly discharged to the outside through the second exhaust port 312, thereby effectively shortening the time that the high-temperature gas generated by the fifth arc-extinguishing grid plate 3651 and the sixth arc-extinguishing grid plate 3661 remains in the housing 31, which is beneficial to improving heat dissipation efficiency.

[0115] Furthermore, the distance between the first partition plate 40 and the second stationary contact 32b along the third direction Z is greater than the distance between the first partition plate 40 and the side wall of the housing 31 where the third exhaust port 313 is located along the third direction Z. The end of the first partition plate 40 along the third direction Z toward the second stationary contact 32b is bent along the second direction Y toward the fourth grid plate group 364. In this way, multiple fourth arc-extinguishing grid plates 3641 located on the side of the first partition plate 40 along the third direction Z toward the second stationary contact 32b are discharged from the air passage formed by the first partition plate 40 and the housing 31 to the third exhaust port 313. The remaining fourth arc-extinguishing grid plates 3641 are mainly discharged from the air passage formed by the first partition plate 40 and the fourth grid plate group 364 to the third exhaust port 313, so as to divert the high-temperature gas generated when the fourth grid plate group 364 extinguishes the arc, shorten the time that part of the high-temperature gas stays in the housing 31, and improve the heat dissipation efficiency. In addition, the high-temperature gas generated by the fourth arc-extinguishing grid 3641 located on the side of the first partition 40 along the third direction Z toward the second stationary contact 32b has a higher temperature than the high-temperature gas generated by other fourth arc-extinguishing grids 3641. The first partition 40 can effectively block this part of the high-temperature gas from entering the second exhaust hole 312, thereby reducing the impact on the heat dissipation of the grids in the fifth grid group 365 and the sixth grid group 366.

[0116] Based on this, the switching unit 30 also includes a second partition 41, which is disposed between the sixth grid plate group 366 and the housing 31 along the second direction Y. Thus, an air passage is formed between the second partition 41 and the housing 31 along the second direction Y, and another air passage is formed between the second partition 41 and the sixth grid plate group 366 along the second direction Y. The distance between the second partition 41 and the first stationary contact 32a along the third direction Z is greater than the distance between the second partition and the housing along the third direction Z. The end of the second partition 41 facing the first stationary contact 32a along the third direction Z is bent towards the sixth grid plate group 366 along the second direction Y. In this way, multiple sixth arc-extinguishing grid plates 3661 located on the side of the second partition 41 facing the first stationary contact 32a along the third direction Z are discharged to the outside through one air channel, while the remaining sixth arc-extinguishing grid plates 3661 are mainly discharged to the outside through another air channel. This diverts the high-temperature gas generated when the sixth grid plate group 366 extinguishes the arc, shortens the time that part of the high-temperature gas remains in the housing 31, and helps to improve the heat dissipation efficiency.

[0117] In one embodiment, the switching unit 30 further includes a fourth vent 314 and a third partition 42. The fourth vent 314 connects the interior of the housing 31 to the outside. The fourth vent 314 is located in the housing 31 and along the third direction Z on the side of the moving contact 33 away from the second vent 312. The fourth vent 314 is further away from the first grid group 361 relative to the first vent 311 along the second direction Y. A third partition 42 is provided between the first grid group 361 and the housing 31 along the second direction Y. The third partition 42 is closer to the fourth vent 314 relative to the first vent 311 along the second direction Y.

[0118] Since the high-temperature gas generated by the first grid group 361 and the high-temperature gas generated by the second grid group 362 are both higher than the high-temperature gas generated by the third grid group 363, the third partition 42 can block some of the high-temperature gas generated by the first grid group 361 and the second grid group 362, so that the high-temperature gas generated by the first grid group 361 and the second grid group 362 is mainly discharged to the outside through the first exhaust port 311, while the high-temperature gas generated by the third grid group 363 is mainly discharged to the outside through the fourth exhaust port 314. In addition, an air passage is formed between the third partition 42 and the housing 31 along the second direction Y, and another air passage is formed between the third partition 42 and the third grid plate group 363 along the second direction Y. The end of the third partition 42 facing the first stationary contact 32a along the third direction Z is bent along the second direction Y towards the third grid plate group 363. In this way, multiple third arc-extinguishing grid plates 3631 on the side of the third partition 42 facing the second stationary contact 32b along the third direction Z are discharged to the outside through one air passage, while the remaining third arc-extinguishing grid plates 3631 are mainly discharged to the outside through the other air passage. This diverts the high-temperature gas generated when the third grid plate group 363 extinguishes the arc, shortens the time that part of the high-temperature gas remains in the housing 31, and helps to improve the heat dissipation efficiency.

[0119] Furthermore, the switching unit 30 also includes a fourth partition 43, which is disposed between the first grid group 361 and the housing 31 along the second direction Y; the distance between the fourth partition 43 and the first stationary contact 32a along the third direction Z is greater than the distance between the fourth partition 43 and the housing 31 along the third direction Z.

[0120] Along the second direction Y, an air passage is formed between the fourth partition 43 and the housing 31, and another air passage is formed between the fourth partition 43 and the first grid plate group 361. Multiple first arc-extinguishing grid plates 3611 located on the side of the fourth partition 43 facing the first stationary contact 32a along the third direction Z are discharged to the outside through one air passage, while the remaining first arc-extinguishing grid plates 3611 are mainly discharged to the outside through another air passage, so as to divert the high-temperature gas generated when the first grid plate group 361 extinguishes the arc, shorten the time that part of the high-temperature gas stays in the housing 31, and help improve the heat dissipation efficiency.

[0121] The first partition 40, the second partition 41, the third partition 42 and the fourth partition 43 may have the same structural shape.

[0122] The following is combined with Figures 15 to 17 The heat dissipation path of the arc extinguishing unit 36 ​​in the switch unit 30 shown is described in detail, wherein, Figure 16 A schematic diagram of the heat dissipation path of another switching unit 30 provided in an embodiment of this application; Figure 17 This is a schematic diagram of the heat dissipation path of another switching unit 30 provided in an embodiment of this application.

[0123] Due to the arrangement of the fourth partition 43, for the first grid plate group 361, a portion of the first arc-extinguishing grid plates 3611 exit through the air passage formed by the fourth partition 43 and the housing 31 (e.g. Figures 15 to 17 The first arc-quenching grid 3611 dissipates heat through the air passage between the fourth partition 43 and the first grid group 361 (as shown by the thick solid line T11 in the figure), and the other part dissipates heat through the air passage between the fourth partition 43 and the first grid group 361 (as shown by the thick solid line T11 in the figure). Figures 15 to 17 (As shown by the thick solid line T12 in the text) for heat dissipation, the high-temperature gas in these two air passages mainly flows along the first guide protrusion 39a along the third direction Z and the gap between the housing 31 to the first exhaust port 311 and is discharged to the outside. For details, please refer to the description of the beneficial effects achieved by the fourth partition 43 in the previous text.

[0124] For the second grid group 362, when the number of the first guide bump 39a is one, such as Figure 15 As shown, the high-temperature gas generated by the second arc-extinguishing grid 3621 flows through the air passage formed by the gap between the first guide bump 39a and the second grid group 362 (as shown). Figure 15 Heat dissipation is achieved through the thick solid line T21 in the diagram. When there are two first guide bumps 39a, the high-temperature gas generated by the second arc-extinguishing grid 3621 dissipates through the air passage formed by the gap between the first guide bump 39a and the second grid group 362 (as shown in the diagram). Figure 16 and Figure 17 The air passage formed by the gap between the two first guide bumps 39a (as shown by the thick solid line T21 in the image) and the air passage formed ...). Figure 16 and Figure 17 The thick solid line T22 in the middle is used for heat dissipation. Among them, due to the setting of the third partition 42, the high temperature gas generated by the second arc extinguishing grid 3621 is mainly discharged to the outside through the first exhaust hole 311.

[0125] Due to the arrangement of the third partition 42, for the third grid plate group 363, a portion of the third arc-extinguishing grid plates 3631 exit through the air passage formed by the third partition 42 and the housing 31 (e.g. Figures 15 to 17 The third arc-quenching grid 3631 dissipates heat from the air passage formed by the third partition 42 and the third grid group 363 (as shown by the thick solid line T31 in the figure). Figures 15 to 17(As shown by the thick solid line T32 in the text) for heat dissipation, the high-temperature gas in these two air passages is mainly discharged to the outside through the fourth exhaust port 314. For details, please refer to the description of the beneficial effects achieved by the third partition 42 in the previous text.

[0126] Due to the arrangement of the first partition 40, for the fourth grid plate group 364, a portion of the fourth arc-extinguishing grid plate 3641 exits from the air passage formed by the first partition 40 and the housing 31 (e.g., Figures 15 to 17 The fourth arc-quenching grid 3641 dissipates heat through the air passage between the first partition 40 and the fourth grid group 364 (as shown by the thick solid line T41 in the figure). Figures 15 to 17 (As shown by the thick solid line T42 in the text) for heat dissipation, the high-temperature gas in these two air passages is mainly discharged to the outside through the third exhaust port 313, for details please refer to the description of the beneficial effects achieved by the first partition 40 in the previous text.

[0127] For the fifth grid group 365, when the number of the second guide bump 39b is one, such as Figure 15 As shown, the high-temperature gas generated by the fifth arc-extinguishing grid 3651 flows through the air passage formed by the gap between the second guide bump 39b and the fifth grid group 365 (as shown). Figure 15 Heat dissipation is achieved through the thick solid line T51 in the diagram. When there are two second guide bumps 39b, the high-temperature gas generated by the fifth arc-extinguishing grid 3651 dissipates through the air passage formed by the gap between the second guide bump 39b and the fifth grid group 365 (as shown in the diagram). Figure 16 and Figure 17 The air passage formed by the gap between the two second guide bumps 39b (as shown by the thick solid line T51 in the image) and the air passage formed by the thick solid line T51 in the image). Figure 17 The thick solid line T52 in the middle is used for heat dissipation. Among them, due to the setting of the third partition 42, the high temperature gas generated by the fifth arc extinguishing grid 3651 is mainly discharged to the outside through the first exhaust hole 311.

[0128] Due to the arrangement of the second partition 41, for the sixth grid plate group 366, a portion of the sixth arc-extinguishing grid plate 3661 exits from the air passage formed by the second partition 41 and the housing 31 (e.g., Figures 15 to 17 The heat dissipation is achieved through the thick solid line T61 in the diagram, while another part of the sixth arc-quenching grid 3661 dissipates heat through the air passage between the second partition 41 and the sixth grid group 366 (as shown in the diagram). Figures 15 to 17 (As shown by the thick solid line T62 in the text) for heat dissipation, the high-temperature gas in these two air passages mainly flows along the second guide protrusion 39b along the third direction Z of the gap between the housing 31 and the second exhaust port 312 and is discharged to the outside. For details, please refer to the description of the beneficial effects achieved by the second partition 41 in the previous text.

[0129] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A photovoltaic inverter, characterized in that, The photovoltaic inverter includes a DC switch and a DC conversion circuit, wherein the DC switch is used to connect the photovoltaic string and the DC conversion circuit. The DC switch includes multiple switch units stacked along a first direction. Each switch unit includes: a housing, a first stationary contact, a second stationary contact, a moving contact, and an arc-extinguishing unit, wherein: The housing is used to house the moving contact and the arc extinguishing unit, and the housing is also used to partially house the first stationary contact and the second stationary contact; The moving contact is disposed between the first stationary contact and the second stationary contact along the second direction. The moving contact can rotate relative to the housing. When the moving contact is in contact with the first stationary contact and the second stationary contact, the DC switch is turned on. When the moving contact is separated from the first stationary contact and the second stationary contact, the DC switch is turned off. The arc extinguishing unit includes a first grid plate group, a second grid plate group, and a third grid plate group. The first grid plate group and the third grid plate group are arranged opposite to each other along the second direction. The second grid plate group is disposed between the first grid plate group and the third grid plate group. The first grid plate group is in contact with the first stationary contact and is located between the first stationary contact and the housing along the third direction. The second grid plate group is located between the moving contact and the housing along the third direction. The third grid plate group is located between the second stationary contact and the housing along the third direction. The first grid plate group includes a plurality of first arc-extinguishing grid plates arranged at intervals along the third direction; the second grid plate group includes a plurality of second arc-extinguishing grid plates arranged at intervals and the second grid plate group protrudes toward the moving contact along the third direction; the third grid plate group includes a plurality of third arc-extinguishing grid plates arranged at intervals along the third direction. The first direction, the second direction, and the third direction are perpendicular to each other.

2. The photovoltaic inverter of claim 1, wherein, The second grid plate group includes a first arc-extinguishing portion and a second arc-extinguishing portion. Along the second direction, the second arc-extinguishing portion is disposed between the first arc-extinguishing portion and the third grid plate group. The first arc-extinguishing portion and the second arc-extinguishing portion are located on opposite sides of the second arc-extinguishing grid plate closest to the moving contact in the second grid plate group. The line connecting the centers of the two second arc-extinguishing grid plates located at the beginning and end of the second arc-extinguishing section is the first straight line, and the line connecting the centers of the two third arc-extinguishing grid plates located at the beginning and end of the third grid plate group is the second straight line. The angle formed by the second straight line and the first straight line is an acute angle.

3. The photovoltaic inverter according to claim 1 or 2, characterized in that The shape of the second grid group projected onto the housing along the first direction is V-shaped.

4. The photovoltaic inverter according to claim 1 or 2, characterized in that The shape of the second grid group projected onto the housing along the first direction is U-shaped.

5. The photovoltaic inverter according to claim 1 or 2, characterized in that, The orthographic projection of the second grid group onto the housing along the first direction is fan-shaped.

6. The photovoltaic inverter according to claim 1 or 2, characterized in that, The shape of the second grid group projected onto the housing along the first direction is C-shaped.

7. The photovoltaic inverter according to claim 1 or 2, characterized in that, The switching unit further includes an arc-initiating element, which is disposed between the moving contact and the arc-extinguishing unit. The arc-initiating element includes two insulating plates spaced apart and arranged opposite to each other along the first direction. The gap formed by the two insulating plates is connected to the gap between adjacent first arc-extinguishing grid plates in the first grid plate group.

8. The photovoltaic inverter according to claim 1 or 2, characterized in that, The switching unit further includes a first vent hole, which is located in the housing and is used to connect the interior of the housing with the outside. Along the second direction, the first vent hole is closer to the third grid group than the first grid group.

9. The photovoltaic inverter according to claim 8, characterized in that, The switching unit further includes a first guide plate, which is disposed between the arc extinguishing unit and the housing and blocks the first exhaust port.

10. The photovoltaic inverter according to claim 9, characterized in that, The switching unit further includes a first flow-guiding bump, which is disposed between the second grid group and the housing along the third direction and located on the side of the second grid group away from the moving contact. The first flow-guiding bump and the first flow-guiding plate are arranged along the second direction. The first flow-guiding bump has a first flow-guiding surface, which is an inclined surface extending from one end of the first flow-guiding bump toward the second grid group to the other end of the first flow-guiding bump away from the second grid group.

11. The photovoltaic inverter according to any one of claims 1, 2, 9 or 10, characterized in that, The arc extinguishing unit further includes a fourth grid plate group, a fifth grid plate group, and a sixth grid plate group. The fourth grid plate group and the sixth grid plate group are arranged opposite to each other along the second direction. The fifth grid plate group is located between the fourth grid plate group and the sixth grid plate group. A second stationary contact is provided between the fourth grid plate group and the third grid plate group along the third direction. The fourth grid plate group contacts the second stationary contact and is located between the second stationary contact and the housing along the third direction. The fifth grid plate group is located between the moving contact and the housing along the third direction. The moving contact is provided between the fifth grid plate group and the second grid plate group along the third direction. The sixth grid plate group is located between the first stationary contact and the housing along the third direction. The first stationary contact is provided between the sixth grid plate group and the first grid plate group. The fourth grid group includes a plurality of fourth arc-extinguishing grids spaced apart along the third direction; the fifth grid group includes a plurality of fifth arc-extinguishing grids spaced apart and the fifth grid group protrudes toward the moving contact along the third direction; the sixth grid group includes a plurality of sixth arc-extinguishing grids spaced apart along the third direction.

12. The photovoltaic inverter according to claim 11, characterized in that, The photovoltaic inverter also includes a circuit board, which is provided with the DC-DC conversion circuit. The switching unit also includes a fixing part disposed on the housing, which is connected to the circuit board. Along the second direction, the fixing part is located on the side of the sixth grid group away from the fourth grid group. The arc extinguishing unit further includes a second vent hole, which is located in the housing and connects the interior of the housing to the outside. Along the second direction, the second vent hole is closer to the fourth grid group than the sixth grid group.

13. The photovoltaic inverter according to claim 12, characterized in that, The switching unit further includes a third vent and a first partition. The third vent is located in the housing and connects the interior and exterior of the housing. Along the second direction, the third vent is further away from the sixth grid group than the second vent. The first partition is disposed between the fourth grid group and the housing along the second direction, and along the second direction, the first partition is closer to the third exhaust port than the second exhaust port.

14. The photovoltaic inverter according to claim 12 or 13, characterized in that, The switching unit further includes a second partition, which is disposed between the sixth grid group and the housing along the second direction; the distance between the second partition and the first stationary contact along the third direction is greater than the distance between the second partition and the housing along the third direction.

15. A DC switch, characterized in that, The system includes multiple switch units stacked along a first direction. Each switch unit comprises: a housing, a first stationary contact, a second stationary contact, a moving contact, and an arc-extinguishing unit, wherein: The housing is used to house the moving contact and the arc extinguishing unit, and the housing is also used to partially house the first stationary contact and the second stationary contact; The moving contact is disposed between the first stationary contact and the second stationary contact along the second direction. The moving contact can rotate relative to the housing. When the moving contact is in contact with the first stationary contact and the second stationary contact, the DC switch is turned on. When the moving contact is separated from the first stationary contact and the second stationary contact, the DC switch is turned off. The arc extinguishing unit includes a first grid plate group, a second grid plate group, and a third grid plate group. The first grid plate group and the third grid plate group are arranged opposite to each other along the second direction. The second grid plate group is disposed between the first grid plate group and the third grid plate group. The first grid plate group is in contact with the first stationary contact and is located between the first stationary contact and the housing along the third direction. The second grid plate group is located between the moving contact and the housing along the third direction. The third grid plate group is located between the second stationary contact and the housing along the third direction. The first grid plate group includes a plurality of first arc-extinguishing grid plates arranged at intervals along the third direction; the second grid plate group includes a plurality of second arc-extinguishing grid plates arranged at intervals and the second grid plate group protrudes toward the moving contact along the third direction; the third grid plate group includes a plurality of third arc-extinguishing grid plates arranged at intervals along the third direction. The first direction, the second direction, and the third direction are perpendicular to each other.

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