A power assembly and photovoltaic inverter

Abstract

The application discloses a power assembly and a photovoltaic inverter. The power assembly comprises a circuit substrate, a plurality of first current conversion units and second current conversion units. Each second current conversion unit comprises a plurality of current conversion tubes. Each current conversion tube of each second current conversion unit is arranged from the outer side to the inner side of the circuit substrate in sequence. From the outer side to the inner side, the current conversion tube located at a position closer to the inner side is farther away from the first current conversion module than another current conversion tube located at a position closer to the outer side. Each second current conversion unit belonging to the same outer side position is arranged in sequence in the up-down direction in a corresponding manner with the current conversion tubes thereof. At least one group of a plurality of current conversion tubes belonging to different second current conversion units and located at the inner side is arranged in an inclined manner from top to bottom and from outside to inside. The power assembly can improve the heat dissipation efficiency of the semiconductor device of the inverter part located at the middle position on the circuit board.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic inverter, in particular to a power assembly and photovoltaic inverter. BACKGROUND

[0002] The photovoltaic inverter can convert the direct current from the photovoltaic assembly into alternating current and deliver the alternating current to the power grid or load. The photovoltaic assembly includes a plurality of photovoltaic strings, each of which includes a plurality of photovoltaic panels connected in series, the photovoltaic panels being used to convert light energy into electrical energy, and each photovoltaic panel generates direct current. In the power circuit board of the photovoltaic inverter, generally includes a boost part and an inverter part, the boost part mostly adopts a BOOST boost circuit of flying capacitor type, after being connected to the external direct current input, the boost part is boosted and output to the inverter part through the bus capacitor; the inverter part adopts NPC or ANPC three-level topology circuit, and through the opening and closing of the switching tube, the direct current input is converted into alternating current output.

[0003] Due to the large number of semiconductor devices on the power circuit board, the power circuit board generates a large amount of heat, which needs to be actively cooled by an external heat sink. One side of the heat sink is in thermal contact with the heat dissipation surface of the semiconductor devices on the circuit board, and then the air flow at the fin position of the heat sink is driven by the fan to carry away the heat of the heat sink. However, the semiconductor devices on the circuit board have uneven heat dissipation. Specifically, generally, the inverter part is arranged at the upper side of the power circuit board, including a plurality of inverter units arranged along the left-right direction, and the boost part is arranged at the lower side of the power circuit board, including a plurality of boost units arranged along the left-right direction and the up-down direction, and the heat sink is usually shared by the boost part and the inverter part, that is, the air flow direction defined by the same heat dissipation fin usually flows along the up-down direction of the board body, and the inverter part located at the upper side and the boost part located at the lower side share the air duct defined by the same heat dissipation fin. In the inverter part, the semiconductor devices located at the middle position in the left-right direction are affected by the heat generated by the other semiconductor devices on both sides thereof and the heat generated by the semiconductor devices of the boost part below, and the air flow direction of the heat sink is from the boost part to the inverter part, and the heat flow driven by the air flow will accumulate heat at the position of the inverter part, and multiple factors affect the heat dissipation efficiency of the semiconductor devices located at the middle position in the inverter part. SUMMARY

[0004] The purpose of the present application is to overcome the above-mentioned defects or problems existing in the background art, and to provide a power assembly and photovoltaic inverter, which can improve the heat dissipation efficiency of the semiconductor devices of the inverter part located at the middle position on the circuit board.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] Technical solution one: a power assembly, comprising a circuit substrate and a first current conversion module and a second current conversion module arranged on the circuit substrate, the first current conversion module and the second current conversion module each form a plurality of first current conversion units and second current conversion units through a plurality of semiconductor switching devices arranged on the first surface of the circuit substrate, wherein the first current conversion module is located above the second current conversion module, and each first current conversion unit in the first current conversion module is arranged in sequence along the left-right direction; the middle position of the circuit substrate in the left-right direction is defined as the inner side, and the two side positions are defined as the outer side; each second current conversion unit includes a plurality of current pipe components formed by semiconductor switching devices, and each current pipe component of each second current conversion unit is arranged in sequence from the outer side of the circuit substrate to the inner side, and from the outer side to the inner side, the current pipe component located closer to the inner side is farther away from the first current conversion module than the adjacent another current pipe component located closer to the outer side; each second current conversion unit belonging to the same outer side position is arranged in sequence in the up-down direction in a corresponding manner with the current pipe components, and at least one group of a plurality of current pipe components belonging to different second current conversion units and located on the inner side is arranged from top to bottom and from outside to inside.

[0007] Technical solution two based on technical solution one: in addition to the outermost current pipe component, the arrangement direction of the other current pipe components of the plurality of second current conversion units belonging to the same outer side position is inclined from top to bottom and from outside to inside.

[0008] Technical solution three based on technical solution one: the arrangement direction of the corresponding current pipe components in the up-down position of the plurality of second current conversion units belonging to the same outer side position is inclined from top to bottom and from outside to inside.

[0009] Technical solution four based on technical solution two or three: the types of the current pipe components include high-loss pipe components and low-loss pipe components, and in the same second current conversion unit, the high-loss pipe components are located at the outer side position of the circuit substrate relative to the low-loss pipe components.

[0010] Technical solution five based on technical solution four: the first current conversion module includes three first current conversion units arranged in sequence at a predetermined distance along the left-right direction, and the boundary between the high-loss pipe components and the low-loss pipe components in each second current conversion unit corresponds to the boundary between the first current conversion unit located at the middle position and the two second current conversion units located at the two side positions.

[0011] Technical solution six based on technical solution four or five: the high-loss pipe component is a controlled on-off switch pipe component, and the low-loss pipe component is a diode component for controlling the direction of current, each second current conversion unit includes two groups of switch pipe components and two groups of diode components, and each group or each two groups of switch pipe components and diode components are suitable for being arranged on the circuit substrate as the current pipe components.

[0012] Based on the technical solution six, the seventh technical solution is that each second current conversion unit further comprises a flying capacitor arranged on the second surface of the circuit substrate and electrically connected with the corresponding current conversion tube; in each second current conversion unit belonging to the same outer side position, the positions of the flying capacitors are correspondingly arranged from top to bottom and from outside to inside in a slanting manner to form two flying capacitor units arranged along the left-right direction; the positions of the flying capacitor units correspond to the boundary between the high-loss tube and the low-loss tube in each second current conversion unit belonging to the same outer side position.

[0013] Based on the seventh technical solution, the eighth technical solution is that a capacitor module arranged on the second surface of the circuit substrate is further included, which is used to connect the first current conversion unit and the second current conversion unit as a bus capacitor; the capacitor module comprises a first capacitor unit and a second capacitor unit; the first capacitor unit is located between the first current conversion unit and the second current conversion unit; the second capacitor unit is located at the middle position of the circuit substrate in the left-right direction, extends into the space between the two flying capacitor units and corresponds to the region in the second current conversion module where no current conversion tube is arranged.

[0014] Based on the eighth technical solution, the ninth technical solution is that the second current conversion module further comprises a flying circuit board arranged close to the flying capacitor unit, the flying circuit board is provided with a plurality of through holes for the air flow to pass through and for the second capacitor unit extending into the space between the two flying capacitor units to dissipate heat; the capacitor devices in the flying capacitor unit are spaced apart from each other at positions corresponding to the through holes to avoid the through holes; the flying circuit board is further provided with a plurality of flying diodes connecting the flying capacitor and the capacitor module, at least part of the flying diodes are arranged across the through holes and the projection shape of the flying diodes on the projection plane perpendicular to the axis direction of the through holes is staggered with the projection shape of the through holes.

[0015] In addition, the present application further provides a tenth technical solution: a photovoltaic inverter comprising the power assembly according to any one of the first to ninth technical solutions and a heat sink for dissipating heat for the power assembly; the first current conversion module and the second current conversion module in the power assembly are respectively used to realize the inverter function and the voltage boosting function; the heat dissipation surface of the heat sink is attached to the semiconductor switching device on the power assembly, and the air flow direction of the heat sink is directed from the position of the second current conversion module to the position of the first current conversion module.

[0016] From the above description of the present application, the present application has the following beneficial effects compared with the prior art:

[0017] The technical scheme one provides a power assembly, which comprises a circuit substrate and two current conversion modules, wherein each first current conversion unit in the first current conversion module is arranged on the circuit substrate in sequence in the left-right direction, and the second current conversion module is located below the first current conversion module; in a conventional circuit device layout, due to the arrangement mode of each first current conversion unit in the first current conversion module, the first current conversion unit located in the middle position is affected by other first current conversion units on its left and right sides, and affected by the second current conversion unit located below it, and at the same time, heat accumulation occurs in the first current conversion unit at this position because the air flow direction of the heat sink is from the second current conversion module to the first current conversion module, so that the heat dissipation efficiency of the first current conversion unit at this position is poor.

[0018] In the technical scheme, the layout of the second current conversion module is improved, and the current conversion pipe fittings of each second current conversion unit in the second current conversion module are distributed in a stepped manner in a gradually far-away mode from the first current conversion module in sequence from outside to inside, so that the current conversion pipe fittings of the second current conversion unit close to the middle position are farther away from the first current conversion module, and the heat generated by the current conversion pipe fittings of the second current conversion unit can have sufficient distance to conduct to other areas not provided with semiconductor devices on the corresponding heat dissipation teeth, instead of only being able to conduct to the first current conversion unit at the end of the air flow, thereby reducing the influence of the heat generated by the current conversion pipe fittings on the heat dissipation of the first current conversion unit. However, simply moving the current conversion pipe fittings to a position farther away from the first current conversion module requires increasing the size of the circuit substrate in the up-down direction or reducing the spacing of the current conversion pipe fittings corresponding to the positions of the adjacent second current conversion units in the up-down direction. In the case where the size of the circuit substrate is limited, the technical scheme creatively inclines the arrangement direction of the multiple current conversion pipe fittings belonging to different second current conversion units from top to bottom and from outside to inside on the inner side, so that the current conversion pipe fittings at the lower position are staggered to the left or right in the up-down direction. This staggered layout can ensure that the adjacent current conversion pipe fittings have sufficient safety distance, and at the same time, the spacing of the current conversion pipe fittings in the up-down direction can be reduced, so that the current conversion pipe fittings can be arranged in a stepped manner without changing the size of the circuit substrate. Furthermore, because the current conversion pipe fittings are arranged in the inclined direction, the air flow of the heat sink passes through less current conversion pipe fittings per unit area during the flow from the position of the second current conversion module to the position of the first current conversion module, so that less heat is accumulated at the position of the first current conversion module, which is more conducive to the heat dissipation of the first current conversion unit at the middle position.

[0019] In the second and third technical solutions, part or all of the current conversion pipe fittings are arranged in the inclined direction. Based on the same natural principle, less heat is accumulated in the first current conversion module, which is beneficial to heat dissipation of the entire first current conversion module. Meanwhile, the distance between each current conversion pipe fitting in the same second current conversion unit can be shortened, and the length of the electrical connection line in the circuit board can also be shortened, thereby reducing the complexity of the electrical connection line layout of the circuit board.

[0020] In the fourth technical solution, the current conversion pipe fittings in the second current conversion unit are divided into high-loss pipe fittings and low-loss pipe fittings according to the loss. In a switching cycle, the high-loss pipe fittings generate more heat than the low-loss pipe fittings. The low-loss pipe fittings with low heat generation are arranged at the inner side of the circuit board, and the high-loss pipe fittings with high heat generation are arranged at the outer side of the circuit board, thereby further reducing the influence of heat generation of the current conversion pipe fittings on heat dissipation of the first current conversion unit located in the middle.

[0021] In the fifth technical solution, three first current conversion units are arranged, and the first current conversion unit located in the middle is separated from the first current conversion units located on both sides by a preset distance to form a partitioned gap. The part of the first current conversion unit located in the middle that is adjacent to the gap is the part with the worst heat dissipation performance. The boundary between the high-loss pipe fittings and the low-loss pipe fittings corresponds to the gap, thereby reducing the influence of the high-loss pipe fittings on heat dissipation of the first current conversion unit located in the middle.

[0022] In the sixth technical solution, the high-loss pipe fittings are controlled on-off switch pipe fittings, and the low-loss pipe fittings are diode fittings for controlling the direction of current. Each group or each two groups of switch pipe fittings and diode fittings can be arranged as current conversion pipe fittings on the circuit board. That is, two groups of switch pipe fittings can be arranged as one current conversion pipe fitting, and two groups of diode fittings can be arranged as two current conversion pipe fittings. In the case that the size of the circuit board is limited, the preferred arrangement scheme can make the current conversion pipe fittings located on the outer side have a proper distance from the first current conversion module, and the distance between the multiple current conversion pipe fittings located on the inner side and the first current conversion module is increased as much as possible.

[0023] In the seventh technical solution, a flying capacitor is arranged to realize the functions of balancing voltage and energy storage. The flying capacitor is arranged in the inclined direction to form a flying unit, and the position of the flying unit corresponds to the wiring between the high-loss pipe fittings and the low-loss pipe fittings in the second current conversion unit. That is, the position of the flying unit is close to the distance between the switch pipe fittings and the diode fittings, thereby reducing the loop area of the entire circuit and reducing the electromagnetic interference between different electrical devices on the circuit board.

[0024] In the eighth technical solution, the capacitor module is arranged as the bus capacitor, the first capacitor unit of the capacitor module is arranged between the first current conversion module and the second current conversion module, the second capacitor unit can be arranged by using the space between the two flying capacitor units and the space between the second current conversion units on the left and right sides, the occupying area of the capacitor module in the up-down direction is reduced, so that the second current conversion module has more space for arrangement on the circuit substrate; and the distance between the second current conversion unit, the flying capacitor unit and the capacitor module can be reduced, so that the high-frequency loop area of the overall circuit is reduced, and the electromagnetic interference between different electrical devices on the circuit substrate is reduced.

[0025] In the ninth technical solution, the flying capacitor board is arranged, the flying capacitor is electrically connected by the flying capacitor board to control the flying capacitor, the through hole is arranged on the flying capacitor board, the spoiler fan can be arranged in the photovoltaic inverter, the wind of the spoiler fan passes through the through hole to cool the second capacitor unit between the two flying capacitor units, and the heat dissipation efficiency of the second capacitor unit between the two flying capacitor units can be improved in the case that the flying capacitor unit is arranged to be inclined to cause a small wind-attacking angle and insufficient wind-attacking area; meanwhile, the flying diode on the flying capacitor board can be arranged corresponding to the through hole, and the flying diode is efficiently cooled by the airflow at the position of the through hole.

[0026] The tenth technical solution provides a photovoltaic inverter, which comprises the power assembly and a heat sink for cooling the power assembly; by adopting the power assembly with improved layout, the photovoltaic inverter has more reliable thermal stability. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the embodiment description are briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 The layout schematic diagram of the first surface of the circuit substrate of the power assembly provided in the first embodiment of the present application is shown in the figure.

[0029] Figure 2 The layout schematic diagram of the second surface of the circuit substrate of the power assembly provided in the first embodiment of the present application is shown in the figure.

[0030] Figure 3 The layout schematic diagram of the flying capacitor board of the power assembly provided in the first embodiment of the present application is shown in the figure.

[0031] Figure 4 The layout schematic diagram of the first surface of the circuit substrate of the power assembly provided in the second embodiment of the present application is shown in the figure.

[0032] Figure 5 Circuit diagram of the second converter module in the power assembly provided for the embodiment 1 or 2 of the present application.

[0033] Explanation of the main reference numerals:

[0034] Circuit substrate 1; first converter module 2; second converter module 3; first converter unit 4; second converter unit 5; first switch tube 6; second switch tube 7; first diode 8; second diode 9; flying capacitor 10; flying capacitor unit 11; capacitor module 12; first capacitor unit 13; second capacitor unit 14; flying capacitor board 15; through hole 16; flying diode 17. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are the preferred embodiments of the present application, and should not be regarded as exclusion of other embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] In the claims, the specification, and the above drawings of the present application, unless otherwise explicitly limited, the terms such as "first", "second", or "third" are used only to distinguish different objects, and are not used to describe a particular order.

[0037] In the claims, the specification, and the above drawings of the present application, unless otherwise explicitly limited, for the terms of orientation, such as "center", "transverse", "vertical", "horizontal", "vertical", "top", "bottom", "inner", "outer", "upper", "lower", "front", "back", "left", "right", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation and position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, so it cannot be understood as limiting the specific protection scope of the present application.

[0038] In the claims, the specification, and the above drawings of the present application, unless otherwise explicitly limited, such as the terms "fixedly connected" or "fixedly connected", should be broadly understood, that is, any connection mode between the two without displacement relationship and relative rotation relationship, that is, it includes non-detachable fixed connection, detachable fixed connection, integration and fixed connection through other devices or elements.

[0039] In the claims, the specification, and the above drawings of the present application, the terms "include", "have" and their variants are intended to mean "include but not limited to".

[0040] Embodiment 1

[0041] Embodiment 1 of the present application provides a power assembly applied to a photovoltaic inverter, which is connected with a PV connection board in the photovoltaic inverter, receives a direct current input of the PV connection board, and converts the direct current input into an alternating current output after boosting and inverting.

[0042] The power assembly comprises a circuit substrate 1 and a first current conversion module 2 and a second current conversion module 3 arranged on the circuit substrate 1. The first current conversion module 2 and the second current conversion module 3 each form a plurality of first current conversion units 4 and second current conversion units 5 through a plurality of semiconductor switching devices arranged on a first surface of the circuit substrate 1. The first current conversion module 2 is located above the second current conversion module 3, and each first current conversion unit 4 in the first current conversion module 2 is arranged in sequence along a left-right direction.

[0043] In the embodiment, the first current conversion module 2 is an inverting module for realizing an inverting function of converting a direct current input into an alternating current output; and the second current conversion module 3 is a boosting module for converting low-voltage direct current input into high-voltage direct current and delivering the high-voltage direct current to the inverting module. The inverting module adopts a conventional ANPC or NPC three-level topology circuit, and realizes the inverting function through controlled opening and closing of power pipe components such as IGBT modules and MOSFET modules in the inverting module. The boosting module adopts a BOOST boosting circuit as shown in Figure 5 The details of the boosting module will be described below. In addition to the IGBT modules and MOSFET modules, the semiconductor switching devices can also include conventional diodes, triodes, etc., which are not limited here.

[0044] Reference Figure 1In the embodiment, the first current conversion module 2 includes three first current conversion units 4 corresponding to three-phase output of alternating current, each having a complete set of ANPC or NPC type three-level topology circuit; the three first current conversion units 4 are arranged in sequence along the left-right direction, which can be regarded as left, middle and right positions each having a first current conversion unit 4 arranged, and there is also a preset distance between the three first current conversion units 4, forming a gap between adjacent first current conversion units 4, which can spatially separate the three-phase first current conversion units 4 and avoid mutual influence of three-phase alternating current output. When the power assembly is working, the three first current conversion units 4 will generate a large amount of heat, and the first current conversion unit 4 in the middle position will be affected by the heat generated by the two first current conversion units 4 on the left and right sides, resulting in a decrease in the heat dissipation efficiency of the first current conversion unit 4 in the middle position. At the same time, the second current conversion module 3 is arranged below the first current conversion module 2, and the heat dissipation fins of the heat sink extend along the up-down direction, and the air flow also flows from bottom to top. The heat of the second current conversion module 3 will affect the first current conversion module 2 above it along with the air flow. If the layout of the first current conversion module 2 is not improved, the heat dissipation efficiency of the first current conversion unit 4 in the middle position of the first current conversion module 2 will be greatly reduced. Among them, Figure 1 The arrow symbol shown indicates the direction of air flow of the heat sink, Figure 2 The arrow symbol in the figure indicates the direction of air flow of the spoiler fan.

[0045] Therefore, the middle position of the circuit board 1 in the left-right direction is defined as the inner side, and the two side positions are defined as the outer side; the second current conversion unit 5 includes a plurality of current pipe elements formed by semiconductor switching devices, each current pipe element of each second current conversion unit 5 is arranged in sequence from the outer side of the circuit board 1 to the inner side, and from the outer side to the inner side, the current pipe element located closer to the inner side is farther away from the first current conversion module 2 than the other current pipe element located closer to the outer side; each second current conversion unit 5 belonging to the same outer side position is arranged in sequence along the up-down direction in a manner that the respective current pipe elements correspond to each other, and at least one group of multiple current pipe elements belonging to different second current conversion units 5 located on the inner side are inclined from top to bottom and from outside to inside.

[0046] Referring to Figure 1The above-mentioned inner side and outer side are relative. The circuit board 1 is divided into a left part and a right part by a middle line in the left-right direction. In the left part or the right part, when one component is arranged closer to the left or right edge of the circuit board 1 relative to another component, it can be said that the component is arranged at an outer side position. Obviously, for the left part of the circuit board 1, a plurality of groups of second current conversion units 5 can be arranged, and for the right part of the circuit board 1, a plurality of groups of second current conversion units 5 can also be arranged. The number of second current conversion units 5 in the left part and the right part can be consistent or different, but in order to balance the arrangement of the second current conversion modules 3 on the circuit board 1, it is preferred that the number of second current conversion units 5 in the left part and the right part is consistent.

[0047] Referring to Figure 5 , which shows a circuit topology structure of one second current conversion unit 5. As a BOOST voltage boosting circuit, the types of current conversion pipe fittings in the second current conversion unit 5 include controlled on-off switching pipe fittings and diode fittings for controlling current direction, and each second current conversion unit 5 includes two groups of switching pipe fittings and two groups of diode fittings, two groups of switching pipe fittings correspond to Figure 5 Q1, Q2 in the circuit, and two groups of diode fittings correspond to Figure 5 D1, D2 in the circuit. Among them, according to the heat loss of the semiconductor switching device in one switching cycle, the types of current conversion pipe fittings are divided into high-loss pipe fittings and low-loss pipe fittings, and the high-loss pipe fittings have higher heat efficiency than the low-loss pipe fittings. For a current conversion pipe fitting, the semiconductor switching device included therein has the following possibilities: first, including a group of switching pipe fittings; second, including a group of diode fittings; third, including two groups of switching pipe fittings; fourth, including two groups of diode fittings. Obviously, since a second current conversion unit 5 only includes two groups of switching pipe fittings and two groups of diode fittings, the first and the third are mutually exclusive, and the second and the fourth are also mutually exclusive.

[0048] Referring to Figure 1 , in this embodiment, one second current conversion unit 5 includes three current conversion pipe fittings, one of which includes two groups of switching pipe fittings, and the other two current conversion pipe fittings each include a group of diode fittings. The three current conversion pipe fittings are arranged in order from the outer side to the inner side of the circuit board 1, so that Figure 1The second current conversion unit 5 with a label in the middle is taken as an example. The second current conversion unit 5 is located at the left side of the circuit substrate 1. Three current conversion pipe fittings are arranged from left to right in sequence. The leftmost current conversion pipe fitting is located at the highest position. The positions of the two current conversion pipe fittings on the right side are sequentially lowered. Thus, from the outside to the inside, the current conversion pipe fitting closer to the inside is farther away from the first current conversion module 2 than the adjacent current conversion pipe fitting closer to the outside, that is, the current conversion pipe fittings are distributed in a stepped manner gradually lowered from the outside to the inside. Meanwhile, the current conversion pipe fitting closer to the inside is closer to the middle position of the circuit substrate 1, which corresponds to the position of the first current conversion unit 4 in the middle of the first current conversion module 2 above. However, the current conversion pipe fitting closer to the middle position is farther away from the first current conversion module 2 in the up-down direction than the current conversion pipe fitting on the outside, so that the heat generated by the current conversion pipe fitting of the second current conversion unit 5 can have enough distance to conduct to other areas not provided with semiconductor devices on the corresponding heat dissipation teeth, rather than only being able to conduct to the first current conversion unit 4 at the end of the air flow, thereby reducing the influence of the heat generated by the current conversion pipe fitting on the heat dissipation of the first current conversion unit 4.

[0049] However, simply moving the current conversion pipe fittings to a position farther away from the first current conversion module 2 requires either increasing the size of the circuit substrate 1 in the up-down direction or reducing the spacing of the current conversion pipe fittings corresponding to the positions of the adjacent second current conversion units 5 in the up-down direction. In the case where the size of the circuit substrate 1 is limited, the present embodiment tilts the arrangement direction of the multiple current conversion pipe fittings belonging to different second current conversion units 5 from top to bottom and from outside to inside on the inside, so that the current conversion pipe fittings with lowered positions are offset to the left or right in the up-down direction. Specifically, referring to Figure 1 In the present embodiment, the left side portion includes three second current conversion units 5 arranged in sequence in the up-down direction. The current conversion pipe fittings corresponding in the up-down position in the three second current conversion units 5 are all arranged and disposed in a tilted manner from top to bottom and from outside to inside. Here, the current conversion pipe fittings corresponding in the up-down position refer to the leftmost current conversion pipe fitting corresponding in the up-down position, the middle current conversion pipe fitting corresponding in the up-down position, and the rightmost current conversion pipe fitting corresponding in the up-down position when the three current conversion pipe fittings of the three second current conversion units 5 are arranged in sequence along the left-right direction. Therefore, the three leftmost current conversion pipe fittings are arranged in a tilted manner relative to the up-down direction along the preset tilt direction, the three middle current conversion pipe fittings are arranged in a tilted manner relative to the up-down direction along the same tilt direction, and the three rightmost current conversion pipe fittings are also arranged in a tilted manner relative to the up-down direction along the same tilt direction. Among them, the current conversion pipe fitting located at the outermost side in a second current conversion unit 5 includes two groups of switch pipe fittings. Each group of switch pipe fittings includes two switches, which are Figure 1The first switch tube 6 and the second switch tube 7 in the middle position are arranged along the left-right direction, and the two groups of switch tube components are arranged along the up-down direction; the current conversion tube component in the middle position includes a group of diode components, the group of diode components includes two diodes, which are Figure 1 The first diode 8 in the middle position, the two diodes are arranged along the same direction as the inclination direction of the current conversion tube component; the current conversion tube component in the right position includes a group of diode components, the group of diode components includes two diodes, which are Figure 1 The second diode 9 in the middle position, the two diodes are arranged along the left-right direction. Through the above arrangement, the three current conversion tube components in a second current conversion unit 5 can be distributed in a stepped manner, and the multiple current conversion tube components in the inner position can be arranged in a predetermined direction in the up-down direction. This inclined arrangement does not require an increase in the size of the circuit board 1 in the left-right direction and the up-down direction. This staggered layout can ensure that there is enough safety distance between adjacent current conversion tube components, while reducing the spacing of the current conversion tube components in the up-down direction, so that the current conversion tube components can be distributed in a stepped manner without changing the size of the circuit board 1. Moreover, since the current conversion tube components are arranged in an inclined direction, the air flow of the heat sink passes through less current conversion tube components per unit area when flowing from the position of the second current conversion module 3 to the position of the first current conversion module 2, so the heat accumulated at the position of the first current conversion module 2 is less, which is more conducive to heat dissipation of the first current conversion unit 4 in the middle position.

[0050] Referring to Figure 1 As can be seen from the above description, in the same second current conversion unit 5, the switch tube component belonging to the high-loss tube component is located at the outer position of the circuit board 1, and the diode component belonging to the low-loss tube component is located at the outer position of the circuit board 1. By arranging the high-loss tube component with high heat generation at the outer position of the circuit board 1, the influence of heat generation of the current conversion tube component on the heat dissipation of the first current conversion unit 4 in the middle position is further reduced.

[0051] Referring to Figure 1The boundary between the high-loss and low-loss components in each second converter unit 5 corresponds to the boundary between the first converter unit 4 located in the middle and the two second converter units 5 located on either side. As described above, a gap space is formed between the first converter unit 4 in the middle and the first converter units 4 on both sides; this gap space is the boundary between the first converter unit 4 and the first converter units 4 on both sides. Similarly, in each second converter unit 5, there is also a boundary between the high-loss and low-loss components. This boundary extends obliquely in the same direction as the inclination of the converter components and is located between the leftmost converter component and the middle converter component. It can also be regarded as a gap space with a certain width. The two boundaries referred to here correspond to each other, referring to the boundary between the obliquely inclination converter components. Moving upwards, it can intersect with the wiring between the first converter units 4 extending vertically. With this layout, high-loss components with high heat generation can be excluded from the first converter unit 4 located in the middle, thereby reducing the impact of high-loss components on the heat dissipation efficiency of the first converter unit 4.

[0052] Reference Figure 2 Each of the second converter units 5 further includes a flying capacitor 10, which is disposed on the second surface of the circuit board 1 and electrically connected to the corresponding converter component; in each of the second converter units 5 belonging to the same outer position, the positions of each flying capacitor 10 are correspondingly arranged obliquely from top to bottom and from outside to inside, to form two flying units 11 arranged in the left-right direction; the position of the flying unit 11 corresponds to the boundary between the high-loss component and the low-loss component in each of the second converter units 5 belonging to the same outer position. Specifically, the flying capacitor 10 is... Figure 5 In the circuit, C1, one end of the flying capacitor 10 in each second converter unit 5 is connected to the cathode of diode D1, and the other end is connected to the midpoint of the two switching transistors Q1 and Q2. It can play the role of balancing voltage and storing energy. Figure 2 In the middle, the three flying capacitors 10 of the second converter unit 5 on the left side cooperate to form a flying unit 11, and the three flying capacitors 10 of the second converter unit 5 on the right side also cooperate to form a flying unit 11. Since the two ends of the flying capacitor 10 are connected to the switching device and the diode, the three sets of flying capacitors 10 in each flying unit 11 are also arranged along the preset tilt direction, so that each set of flying capacitors 10 and the converter device in the corresponding second converter unit 5 have a sufficiently short trace length, thereby reducing the loop area of ​​the overall circuit and reducing the electromagnetic interference between different electrical components on the circuit board 1.

[0053] In addition, a capacitor module 12 is provided on the second side of the circuit board 1. The capacitor module 12 is used as a bus capacitor to connect the first converter unit 4 and the second converter unit 5, that is... Figure 5C2 and C3 in the circuit. The capacitor module 12 comprises a first capacitor unit 13 and a second capacitor unit 14; the first capacitor unit 13 is located between the first current conversion unit 4 and the second current conversion unit 5; the second capacitor unit 14 is located at the middle position of the circuit substrate 1 in the left-right direction, and extends into the space between the two flying capacitor units 11 and corresponds to the region in the second current conversion module 3 where no current conversion pipe is arranged. It should be noted that the first capacitor unit 13 and the second capacitor unit 14 here are divided according to the position of the capacitor, not the circuit structure, and the first capacitor unit 13 and the second capacitor unit 14 do not correspond to C2 and C3. For reference Figure 2 , the first capacitor unit 13 refers to a group of capacitors arranged in the left-right direction at the upper position, and the second capacitor unit 14 refers to capacitors arranged in a stepped manner not only in the left-right direction but also in the up-down direction, which extend into the space between the two flying capacitor units 11 and correspond to the space between the second current conversion unit 5 on the left side and the second current conversion unit 5 on the right side on the first surface. In this way, the second capacitor unit 14 can be arranged using the space between the two flying capacitor units 11 and the space between the second current conversion units 5 on the left and right sides, reducing the occupied area of the capacitor module 12 in the up-down direction, so that the second current conversion module 3 has more space for arrangement on the circuit substrate 1; and the distance between the second current conversion unit 5, the flying capacitor unit 11 and the capacitor module 12 can be reduced, thereby reducing the high-frequency loop area of the overall circuit and reducing the electromagnetic interference between different electrical devices on the circuit substrate 1.

[0054] For reference Figure 2 , the second current conversion module 3 further comprises a flying circuit board 15 arranged close to the flying capacitor unit 11, and the flying circuit board 15 is provided with a plurality of through holes 16 for air flow and heat dissipation for the second capacitor unit 14 extending into the space between the two flying capacitors 10; the capacitor devices of the flying capacitors 10 in the flying capacitor unit 11 are spaced apart from each other at positions corresponding to the through holes 16 to avoid the through holes 16; the flying circuit board 15 is further provided with a plurality of flying diodes 17 connecting the flying capacitors 10 and the capacitor module 12, at least part of the flying diodes 17 are arranged across the through holes 16 and their projection shape in the projection plane perpendicular to the axis of the through holes 16 is staggered with the projection shape of the through holes 16. The flying diodes 17 here refer to Figure 5 D3 in the circuit, the flying circuit board 15 is fixed on the second surface of the circuit substrate 1, for reference Figure 3The pin of the flying capacitor 10 is welded on the flying circuit board 15, and the flying diode 17 is also welded on the flying circuit board 15, wherein the flying capacitor 10 is separated by the through hole 16 to form a layout arranged at intervals, so that the through hole 16 can pass through the airflow; meanwhile, the flying diode 17 is arranged across the through hole 16, and the size of the flying diode 17 does not cover the through hole 16, but makes the airflow of the through hole 16 directly contact the heat dissipation surface of the flying diode 17, thereby taking away the heat of the flying diode 17. In the space where the power assembly is arranged, a turbulence fan can be arranged, which is generally arranged at the outer side of the power assembly, so that the airflow of the turbulence fan is blocked by the flying unit 11 which is higher than the circuit board 1. In the embodiment, the through hole 16 is arranged on the flying circuit board 15, so that the airflow of the turbulence fan can pass through the through hole 16 to dissipate heat for the second capacitor unit 14 between the two flying units 11. Meanwhile, the second capacitor unit 14 between the two flying units 11 can improve the heat dissipation efficiency in the case that the flying unit 11 is arranged at a small wind angle and insufficient wind area.

[0055] Embodiment 2

[0056] With reference to Figure 4 Embodiment 2 of the present application also provides a power assembly, which is different from Embodiment 1 in that the arrangement direction of the second current conversion unit 5 located at the same outer side position is inclined from top to bottom and from outside to inside, except for the outermost current conversion pipe element. Specifically, the outermost current conversion pipe element is arranged vertically along the up-down direction, and the inner current conversion pipe element is arranged at a preset inclined direction. Since the high-loss pipe element is located at the outer side position and is relatively far away from the first current conversion unit 4 located at the middle position, the heat dissipation efficiency of the first current conversion module 2 can be improved.

[0057] Of course, in other embodiments, the outermost current conversion pipe element and the middle current conversion pipe element can also be arranged vertically along the up-down direction, and only the innermost current conversion pipe element is arranged at an inclined direction, which can also improve the heat dissipation efficiency of the first current conversion module 2 to a certain extent. Of course, compared with Embodiment 1, the above layout mode will reduce the improvement effect on the heat dissipation efficiency.

[0058] Embodiment 3

[0059] Embodiment 3 of the present application provides a photovoltaic inverter, which comprises the power assembly provided in Embodiment 1 or 2, and a heat sink for dissipating heat for the power assembly. The first current conversion module 2 and the second current conversion module 3 in the power assembly are respectively used to realize the functions of inversion and voltage increase. The heat dissipation surface of the heat sink is attached to the semiconductor switching device on the power assembly, and the airflow direction of the heat sink is directed from the position of the second current conversion module 3 to the position of the first current conversion module 2.

[0060] Specifically, the heat sink comprises a heat sink plate and a set of heat sink fans, the heat sink fans are arranged in the photovoltaic inverter below the power assembly, the heat sink plate is arranged on one side of the power assembly in the thickness direction and close to the first surface of the circuit substrate 1, and the heat dissipation surface on the heat sink plate is attached to the semiconductor switching device on the power assembly. In use, the heat sink fans suck in the external cold air with low temperature and flow through the gap between the heat dissipation teeth of the heat sink plate, taking away the heat of the heat dissipation teeth, and the heat sink plate also takes away the heat of the semiconductor switching device, Figure 1 The arrow direction in the figure indicates the flow direction of the air flow of the heat sink fans, and the direction is from the position of the second current conversion module 3 to the position of the first current conversion module 2. The photovoltaic inverter has more reliable thermal stability by adopting the layout improved power assembly.

[0061] The above description and embodiment description are used to explain the protection scope of the present application, but do not constitute the limitation of the protection scope of the present application. Through the inspiration of the present application or the above embodiment, the modification, equivalent replacement or other improvement of the embodiment of the present application or one part of the technical features can be obtained by the ordinary skilled in the art combining with the common knowledge, the ordinary technical knowledge in the art and / or the prior art through the logical analysis, reasoning or limited test, which should be included in the protection scope of the present application.

Claims

1. A power assembly comprising a circuit board (1) and a first current conversion module (2) and a second current conversion module (3) arranged on the circuit board (1), the first current conversion module (2) and the second current conversion module (3) each forming a plurality of first current conversion units (4) and a plurality of second current conversion units (5) by a plurality of semiconductor switching devices arranged on a first side of the circuit board (1), wherein the first current conversion module (2) is arranged above the second current conversion module (3), and each first current conversion unit (4) in the first current conversion module (2) is arranged in sequence along a left-right direction; characterized in that: a middle position of the circuit board (1) along the left-right direction is an inner side, and both side positions are outer sides; each second current conversion unit (5) comprises a plurality of current pipe elements formed by semiconductor switching devices, each current pipe element of each second current conversion unit (5) is arranged in sequence from an outer side to an inner side of the circuit board (1), and from the outer side to the inner side, a current pipe element located closer to the inner side is farther away from the first current conversion module (2) than an adjacent current pipe element located closer to the outer side; each second current conversion unit (5) belonging to the same outer side position is arranged in sequence along an up-down direction in a manner that the current pipe elements of each second current conversion unit (5) correspond to each other, and at least one group of a plurality of current pipe elements belonging to different second current conversion units (5) and located on the inner side is arranged in a direction from top to bottom and from outside to inside; except for the outermost current pipe element, the arrangement direction of the other current pipe elements of each second current conversion unit (5) belonging to the same outer side position is inclined from top to bottom and from outside to inside; the arrangement direction of the corresponding current pipe elements of each second current conversion unit (5) belonging to the same outer side position in the up-down position is inclined from top to bottom and from outside to inside; the types of the current pipe elements include high-loss pipe elements and low-loss pipe elements, and in the same second current conversion unit (5), the high-loss pipe elements are located on the outer side of the circuit board (1) relative to the low-loss pipe elements. The first current conversion module (2) comprises three first current conversion units (4) arranged in sequence along the left-right direction at a predetermined distance, and the boundary between the high-loss pipe elements and the low-loss pipe elements in each second current conversion unit (5) corresponds to the boundary between the first current conversion unit (4) located in the middle position and the two second current conversion units (5) located on both side positions. Definitions The high-loss pipe elements are controlled on-off switching pipe elements, and the low-loss pipe elements are diode elements for controlling the direction of current, each second current conversion unit (5) comprises two groups of switching pipe elements and two groups of diode elements, and each group or each two groups of switching pipe elements and diode elements are suitable for being arranged on the circuit board (1) as the current pipe elements. ​ ​ ​ ​ ​ 2. A power pack as claimed in claim 1, characterised in that ​ 3. A power pack as claimed in claim 1 or 2, characterised in that, ​ 4. A power pack as claimed in claim 3, characterised in that Each of the second current conversion units (5) further comprises a flying capacitor (10) disposed on the second surface of the circuit substrate (1) and electrically connected with the corresponding current conversion tube; in each of the second current conversion units (5) belonging to the same outer position, each of the flying capacitors (10) is disposed correspondingly from top to bottom and from outside to inside in a slanting manner to form two flying capacitor units (11) arranged along the left-right direction; the position of the flying capacitor unit (11) corresponds to the boundary between the high-loss tube and the low-loss tube in each of the second current conversion units (5) belonging to the same outer position.

5. A power pack as claimed in claim 4, characterised in that Further comprising a capacitor module (12) disposed on the second surface of the circuit substrate (1) and used for connecting the first current conversion unit (4) and the second current conversion unit (5) as a bus capacitor; the capacitor module (12) comprises a first capacitor unit (13) and a second capacitor unit (14); the first capacitor unit (13) is located between the first current conversion unit (4) and the second current conversion unit (5); the second capacitor unit (14) is located at the middle position of the circuit substrate (1) in the left-right direction, extends into between the two flying capacitor units (11) and is located correspondingly to the region in the second current conversion module (3) where no current conversion tube is disposed.

6. A power pack as claimed in claim 5, characterised in that The second current conversion module (3) further comprises a flying circuit board (15) disposed close to the flying capacitor unit (11); the flying circuit board (15) is provided with a plurality of through holes (16) for the air flow to pass through and for the second capacitor unit (14) extending into between the two flying capacitor units (10) to dissipate heat; the capacitor devices of the flying capacitor units (10) in the flying capacitor unit (11) are spaced apart from each other at positions corresponding to the through holes (16) to avoid the through holes (16); the flying circuit board (15) is further provided with a plurality of flying diodes (17) connecting the flying capacitor units (10) and the capacitor module (12); at least part of the flying diodes (17) are disposed across the through holes (16) and the projection shape of the flying diodes (17) in the projection plane perpendicular to the axial direction of the through holes (16) is staggered with the projection shape of the through holes (16).

7. A photovoltaic inverter, characterized by The power assembly comprises the power assembly and a heat sink for dissipating heat for the power assembly; the first current conversion module (2) and the second current conversion module (3) in the power assembly are respectively used for realizing the functions of inversion and voltage increase; the heat dissipation surface of the heat sink is attached to the semiconductor switching devices on the power assembly, and the air flow direction of the heat sink is directed from the position of the second current conversion module (3) to the position of the first current conversion module (2).

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