Phase-shifting transformer and medium-voltage frequency converter adopting same
By adopting a top-down layout of the phase-shifting transformer and power unit combination in the medium-voltage inverter, a compact structure with single-sided maintenance and simplified terminal wiring is achieved, solving the problems of large space and lead breakage in the traditional layout, and reducing costs and risks.
Patent Information
- Application Number
- CN202422904289.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-10-21
- Estimated Expiration
- 2034-11-26
AI Technical Summary
In traditional medium-voltage inverters, the back-to-back layout of the phase-shifting transformer and power unit group results in a large footprint and high material consumption, and the horizontal arrangement of the secondary-side output terminals is complex, which easily causes lead breakage problems.
The inverter layout scheme adopts a top-down layout, the output terminal group of the phase-shifting transformer is arranged vertically, the power units are connected in parallel, the terminal arrangement and lead connection are optimized, the number of secondary windings is reduced, and larger-gauge wire is used.
It simplifies terminal wiring, reduces the risk of lead breakage, optimizes device layout, reduces welding workload and insulation paper usage, and reduces costs.
Smart Images
Figure CN223462094U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of electrical equipment, more particularly, to a phase-shifting transformer and a medium-voltage frequency converter using the same. BACKGROUND
[0002] The medium-voltage frequency converter is mainly composed of a phase-shifting transformer and a power unit group. In the conventional medium-voltage frequency converter, the phase-shifting transformer and the power unit group are arranged in a back-to-back manner, which occupies a large area and requires more materials. With the development of the industry, the requirements for the price and the occupied space of the medium-voltage frequency converter in various application fields are increasing, and accordingly, a frequency converter layout scheme with an up-down arrangement is proposed. However, due to the height limitation of the phase-shifting transformer, the output terminal of the secondary side is arranged in a horizontal manner. When the terminal layout is used, the transformer lead needs to be concentrated, and the operation is complex. For small-capacity transformers, the wire gauge is small, and the complex operation is prone to cause lead metal fatigue, and further cause lead breakage and other problems during transportation. CONTENT OF THE UTILITY MODEL
[0003] The technical problem to be solved by the present application is to provide a phase-shifting transformer and a medium-voltage frequency converter using the same, which can simplify the terminal wiring and reduce the risk of lead breakage by optimizing the terminal arrangement.
[0004] To solve the technical problem, the present application provides a phase-shifting transformer in the first aspect, which comprises a plurality of primary side input terminal, 3×n secondary side output terminal groups and a plurality of taps, n is an integer greater than or equal to 2, wherein: the phase-shifting transformer has a first face and a second face arranged oppositely, the lower part of the first face of the phase-shifting transformer is provided with an input terminal area, the upper part is provided with a tap area, and the output terminal area is arranged between the input terminal area and the tap area; the plurality of primary side input terminals are arranged in the input terminal area in a horizontal manner; the plurality of taps are arranged in the tap area in a horizontal manner; the 3×n secondary side output terminal groups comprise a first phase output terminal group area, a second phase output terminal group area and a third phase output terminal group area arranged in the output terminal area in a longitudinal manner, the first phase output terminal group area, the second phase output terminal group area and the third phase output terminal group area each have n secondary side output terminal groups, and the n secondary side output terminal groups are arranged in a longitudinal manner in the first unit and the second unit arranged in a horizontal manner.
[0005] According to an embodiment of the second aspect of the present application, each secondary side output terminal group comprises three secondary side output terminals arranged in a horizontal manner.
[0006] According to an embodiment of the first aspect of the present application, the plurality of primary-side input terminals comprises three primary-side input terminals respectively electrically connected with three-phase input.
[0007] According to an embodiment of the first aspect of the present application, the plurality of taps comprises a main tap, a positive tap and a negative tap.
[0008] According to an embodiment of the first aspect of the present application, the phase-shifting transformer further comprises a plurality of current transformers, the plurality of current transformers are arranged transversely on the first surface of the phase-shifting transformer between the tap area and the output terminal area.
[0009] According to an embodiment of the first aspect of the present application, the phase-shifting transformer further comprises an auxiliary power winding, the auxiliary power winding is arranged on the first surface of the phase-shifting transformer between the plurality of current transformers and the output terminal area.
[0010] According to an embodiment of the first aspect of the present application, the first surface of the phase-shifting transformer is the front surface of the medium-voltage frequency converter.
[0011] To solve the technical problems, the present application provides a medium-voltage frequency converter in the second aspect, comprising a phase-shifting transformer and a power unit arrangement chamber above the phase-shifting transformer, the power unit arrangement chamber is provided with 3×2n power units, the phase-shifting transformer is the aforementioned phase-shifting transformer, and each secondary-side output terminal group (127) in the phase-shifting transformer (100) is connected in parallel with two power units.
[0012] According to an embodiment of the second aspect of the present application, the 3×2n power units comprise 2n first-phase power units connected in series, 2n second-phase power units connected in series and 2n third-phase power units connected in series, the 2n first-phase power units connected in series, the 2n second-phase power units connected in series and the 2n third-phase power units connected in series are connected in a star type, and each two power units in the 2n first-phase power units connected in series, the 2n second-phase power units connected in series and the 2n third-phase power units connected in series are respectively connected in parallel with one of the n secondary-side output terminal groups in the first-phase output terminal group area, the second-phase output terminal group area and the third-phase output terminal group area.
[0013] According to an embodiment of the second aspect of the application, the power unit arrangement chamber has a first face and a second face arranged oppositely, the first face of the power unit arrangement chamber is provided with a first face first layer arrangement area and a first face second layer arrangement area arranged longitudinally, and the second face of the power unit arrangement chamber is provided with a second face first layer arrangement area and a second face second layer arrangement area arranged longitudinally; at least part of the 2n first-phase power units in series is arranged laterally in the first face first layer arrangement area, and a lateral first end of the first face first layer arrangement area serves as a first-phase output end; at least part of the 2n second-phase power units in series is arranged laterally in the first face second layer arrangement area, and a lateral first end of the first face second layer arrangement area corresponding to the first face first layer arrangement area serves as a second-phase output end; the 2n third-phase power units in series are arranged laterally in the second face first layer arrangement area and the second face second layer arrangement area respectively near one side of the lateral first end and are connected longitudinally in series alternately, and a corresponding lateral first end of the second face first layer arrangement area or the second face second layer arrangement area serves as a third-phase output end; the rest of the 2n first-phase power units in series and the rest of the 2n second-phase power units in series are arranged laterally in the second face first layer arrangement area and the second face second layer arrangement area respectively away from the lateral first end, and one first-phase power unit in the first face first layer arrangement area at a lateral second end is electrically connected to one first-phase power unit in the second face first layer arrangement area at a corresponding lateral second end, and one second-phase power unit in the first face second layer arrangement area at a lateral second end is electrically connected to one second-phase power unit in the second face second layer arrangement area at a corresponding lateral second end.
[0014] According to an embodiment of the second aspect of the application, the first face of the power unit arrangement chamber is a front face or a back face of the medium-voltage frequency converter.
[0015] The phase-shifting transformer and the medium-voltage frequency converter adopting the same have the following beneficial effects: the phase-shifting transformer according to the embodiment of the application arranges the first-phase output terminal group area, the second-phase output terminal group area and the third-phase output terminal group area longitudinally on one side of the transformer, which facilitates the single-side maintenance requirement of the compact structure and provides space for the layout optimization of the whole device; the phase-shifting transformer according to the embodiment of the application longitudinally arranges n secondary-side output terminal groups in each phase output terminal group area on the two sides in the transverse direction, and connects two power units in parallel in each secondary-side output terminal group, thereby reducing the number of secondary-side windings of the phase-shifting transformer by half, reducing the wire welding workload by half and reducing the wire arrangement process difficulty; moreover, the two power units connected with one secondary-side terminal group are connected in parallel, the secondary-side winding wire of the phase-shifting transformer needs to be selected in a larger specification compared with the traditional scheme, and the wire breakage problem of the small-capacity transformer caused by the small wire specification is avoided, and the wire breakage risk is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS
[0016] The application will be further described below in combination with the drawings and embodiments, in which:
[0017] Figure 1 is a layout structure schematic diagram of a first side of a medium-voltage frequency converter according to an embodiment of the application;
[0018] Figure 2 is Figure 1 a layout structure schematic diagram of a second side of the medium-voltage frequency converter shown in FIG. 2;
[0019] Figure 3 is a layout structure schematic diagram of a first side of a phase-shifting transformer cabinet according to an embodiment of the application;
[0020] Figure 4 is Figure 3 a connection mode schematic diagram of each group of secondary-side windings and two power units in the phase-shifting transformer cabinet shown in FIG. 4.
[0021] Brief Description of Drawings: 1000 - medium voltage frequency converter; 100 - phase shifting transformer; 110 - first face; 120 - second face; 11 - input terminal block area; 111 - primary input terminal; 12 - output terminal block area; 121 - first phase output terminal block area; 122 - second phase output terminal block area; 123 - third phase output terminal block area; 124 - secondary output terminal; 125 - first unit; 126 - second unit; 127 - secondary output terminal block; 13 - tap block area; 131 - tap; 14 - current transformer; 15 - auxiliary power winding; 200 - power unit arrangement chamber; 210 - first face; 211 - first face first layer arrangement area; 212 - first face second layer arrangement area; 220 - second face; 221 - second face first layer arrangement area; 222 - second face second layer arrangement area; 21 - first phase power unit; 22 - second phase power unit; 23 - third phase power unit; OUT1 - first phase output terminal; OUT2 - second phase output terminal; OUT3 - third phase output terminal. DETAILED DESCRIPTION
[0022] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application. Moreover, the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.
[0023] Figure 1 and Figure 2 respectively show the layout structure schematic diagrams of the oppositely arranged first face and second face of the medium voltage frequency converter 1000 according to an embodiment of the present application. Referring to Figure 1 and Figure 2 shown, the medium voltage frequency converter 1000 comprises the phase shifting transformer 100 and the power unit arrangement chamber 200 located above the phase shifting transformer 100, and the two are arranged in an up-down layout. Wherein, the power unit arrangement chamber 200 has the oppositely arranged first face 210 and second face 220. The first face 210 of the power unit arrangement chamber 200 is provided with the longitudinally arranged first face first layer arrangement area 211 and first face second layer arrangement area 212. Similarly, the second face 220 of the power unit arrangement chamber 200 is provided with the longitudinally arranged second face first layer arrangement area 221 and second face second layer arrangement area 222. Referring to Figure 1 and Figure 2As shown, the power unit arrangement chamber 200 is provided with 3x2n power units, n is an integer greater than or equal to 2, including 2n first-phase power units 21 connected in series, 2n second-phase power units 22 connected in series and 2n third-phase power units 23 connected in series, which are connected in a star type. And, at least part of the 2n first-phase power units 21 are arranged in the first surface first layer arrangement area 211 in a transverse direction, and the left side of the first surface first layer arrangement area 211 (i.e. the left side in Figure 1 ) is taken as the first-phase output end OUT1. Similarly, at least part of the 2n second-phase power units 22 are arranged in the first surface second layer arrangement area 212 in a transverse direction, and the left side of the first surface second layer arrangement area 212 (i.e. the left side in Figure 1 ) corresponding to the first surface first layer arrangement area 211 is taken as the second-phase output end OUT2. The 2n third-phase power units 23 are arranged in the second surface first layer arrangement area 221 and the second surface second layer arrangement area 222 respectively near the side of the corresponding transverse first end (i.e. the right side in Figure 2 ), and the third-phase power units 23 in the second surface first layer arrangement area 221 and the second surface second layer arrangement area 222 are connected in series in a longitudinal direction, and the right side of the corresponding transverse first end (i.e. the right side in Figure 2 ) of the second surface first layer arrangement area 221 or the second surface second layer arrangement area 222 is taken as the third-phase output end OUT3, so that the first output end OUT1 of the 2n first-phase power units 21, the second output end OUT2 of the 2n second-phase power units 22 and the third output end OUT3 of the 2n third-phase power units 23 are located on the same side of the medium voltage frequency converter 1000, which facilitates the electrical connection between the power unit arrangement chamber 200 and the load. Further referring to Figure 1 and Figure 2 , the remaining part of the 2n first-phase power units 21 are arranged in the second surface first layer arrangement area 221 away from the side of the transverse first end (i.e. the left side in Figure 2 ), and one first-phase power unit 21 in the first surface first layer arrangement area 211 and one first-phase power unit 21 in the second surface first layer arrangement area 221 corresponding to the transverse second end are electrically connected to realize the series connection of the 2n first-phase power units 21. Similarly, the remaining part of the 2n second-phase power units 22 are arranged in the second surface second layer arrangement area 222 away from the side of the transverse first end (i.e. the left side in Figure 2The left side of the diagram is shown in FIG2 ), and a second-phase power unit 22 at a second lateral end in the second-layer arrangement area 212 of the first surface is electrically connected to a second-phase power unit 22 at a corresponding second lateral end in the second-layer arrangement area 222 of the second surface to realize the series connection of the 2n second-phase power units 22.
[0024] Specifically in Figure 1 and Figure 2 In the illustrated embodiment, the power unit arrangement chamber 200 is provided with 8 first-phase power units 21 connected in series, 8 second-phase power units 22 connected in series, and 8 third-phase power units 23 connected in series, wherein the 6 first-phase power units 21 are arranged horizontally in series in the first-layer arrangement area 211 of the first surface, with the leftmost side being the first-phase output terminal OUT1, and the 6 second-phase power units 22 are arranged horizontally in series in the second-layer arrangement area 212 of the first surface, with the leftmost side being the second-phase output terminal OUT2. The 8 third-phase power units 23 are divided into two rows and arranged horizontally in the first-layer arrangement area 221 of the second surface and the second-layer arrangement area 222 of the second surface, respectively, on one side close to the first-phase output terminal OUT1 and the second-phase output terminal OUT2. Each third-phase power unit 23 in the first-layer layout area 221 of the second surface is electrically connected to a corresponding third-phase power unit 23 in the second-layer layout area 222 of the second surface below it, and is also electrically connected to the next third-phase power unit 23 in the second-layer layout area 222 of the second surface below it, so as to realize longitudinal staggered series connection. The last third-phase power unit 23 in the first-layer layout area 221 of the second surface is connected to the third-phase output terminal OUT3, and the first third-phase power unit 23 in the second-layer layout area 222 of the second surface is electrically connected to the last second-phase power unit 22 in the second-layer layout area 222 of the second surface and the last first-phase power unit 21 in the first-layer layout area 221 of the second surface at the same time, so as to realize star connection.
[0025] According to the aforementioned embodiment of the present application, the power cell arrangement chamber 200 is arranged on two sides, front and back, and in two layers. This allows for a compact arrangement of the 3×2n power cells, facilitating the aesthetic routing of the cables connecting the power cells, reducing the number of cables used, and facilitating the connection between the power cell arrangement chamber 200 and the load via wiring cables. Furthermore, depending on the installation position of the medium-voltage transformer 1000, the first side 210 and the second side 220 of the power cell arrangement chamber 200 can both serve as the front and back sides of the medium-voltage transformer 1000, and the first-phase output terminal OUT1, the second-phase output terminal OUT2, and the third-phase output terminal OUT3 can be located on either the left or right side of the medium-voltage transformer 1000.
[0026] See also Figure 1 、 Figure 2 Combine Figure 3As shown, the phase-shifting transformer 100 has a first face 110 and a second face 120 oppositely arranged corresponding to the power unit arrangement chamber 200, and preferably the first face 110 is the front face of the medium-voltage frequency converter 1000. Referring to Figure 3 As shown, the phase-shifting transformer 100 is provided with an input terminal area 11 at the lower part of the first face 110, a tapping area 13 at the upper part of the first face 110, and an output terminal area 12 between the input terminal area 11 and the tapping area 13. The input terminal area 11 is provided with a plurality of primary-side input terminals 111 arranged in a horizontal direction, the tapping area 13 is provided with a plurality of taps 131 arranged in a horizontal direction, and the output terminal area 12 is provided with 3×n groups of secondary-side output terminals 127 arranged in a vertical direction, for electrically connecting with 3×2n power units in the power unit arrangement chamber 200 in a one-to-two manner. Specifically, in the embodiment shown in Figure 3 In the embodiment shown, the input terminal area 11 is provided with three primary-side input terminals 111 arranged in a horizontal direction, which are electrically connected with three-phase input power. The tapping area 13 is provided with three taps 131 arranged in a horizontal direction, which can be a main tap, a positive tap and a negative tap, for adjusting the secondary-side output voltage of the phase-shifting transformer 100. Referring to Figure 3 As shown, the phase-shifting transformer 100 is further provided with a plurality of current transformers 14 arranged in a horizontal direction between the tapping area 13 and the output terminal area 12 of the first face 110, and an auxiliary power supply winding 15 arranged between the plurality of current transformers 14 and the output terminal area 12 of the first face 110. The phase-shifting transformer 100 optimizes the arrangement of the transformer lead local part and the terminals, and simplifies the terminal connection, by the reasonable arrangement of the terminals and the device mounting positions.
[0027] Further referring to Figure 3 As shown, the 3×n groups of secondary-side output terminals 127 are arranged in a vertical direction in a first-phase output terminal group area 121, a second-phase output terminal group area 122 and a third-phase output terminal group area 123 in the output terminal area 12. Each of the first-phase output terminal group area 121, the second-phase output terminal group area 122 and the third-phase output terminal group area 123 has n groups of secondary-side output terminals 127, and the n groups of secondary-side output terminals 127 in each area are arranged in a vertical direction in a first unit 125 and a second unit 126 arranged in a horizontal direction on both sides of the output terminal area 12. Compared with the conventional cascaded medium-voltage frequency converter in which each secondary-side winding is connected with one power unit, the phase-shifting transformer 100 in the embodiment of the present application adopts a connection mode in which each secondary-side winding is connected with two power units in parallel (see Figure 4The input current harmonics can also meet the national standard requirements by calculating the scheme of connecting two power units in parallel for each secondary side winding. Therefore, each secondary side output terminal group 127 in the first unit 125 and the second unit 126 is connected in parallel with the corresponding two power units. Further, the three secondary side output terminals 124 in each secondary side output terminal group 127 are arranged transversely.
[0028] Specifically in Figure 3 In the embodiment shown, corresponding to the 8 series-connected first-phase power units 21, 8 series-connected second-phase power units 22 and 8 series-connected third-phase power units 23 in the power unit arrangement chamber 200, the first-phase output terminal group area 121, the second-phase output terminal group area 122 and the third-phase output terminal group area 123 of the phase-shifting transformer 200 respectively have 4 secondary side output terminal groups 127, the first unit 125 and the second unit 126 each have 2 secondary side output terminal groups 127 arranged longitudinally, and each secondary side output terminal group 127 is electrically connected with the corresponding 2 power units in the power unit arrangement chamber 200.
[0029] According to the phase-shifting transformer 100 in the above-mentioned embodiments of the present application, the first-phase output terminal group area 121, the second-phase output terminal group area 122 and the third-phase output terminal group area 123 are arranged longitudinally on one side of the phase-shifting transformer 100, which facilitates the single-side maintenance requirement of the compact structure and also provides space for the overall device layout optimization. According to the phase-shifting transformer 100 in the above-mentioned embodiments of the present application, the n secondary side output terminal groups 127 in each phase output terminal group area are arranged longitudinally on both sides in the transverse direction, and each secondary side output terminal group 127 is connected with two power units in parallel, so that the number of secondary side windings of the phase-shifting transformer 100 can be reduced by half, the wire welding workload is halved, and the wire arrangement process difficulty is reduced. Moreover, the two power units connected with one secondary side output terminal group 127 are connected in parallel, and the secondary side winding wire of the phase-shifting transformer 100 needs to be selected in a larger specification compared with the traditional scheme, thereby avoiding the wire breakage problem of small-capacity transformers caused by small wire specifications. The secondary side output terminal group layout mode of the phase-shifting transformer 100 also simplifies the wire process, avoids repeated bending of the wire, greatly reduces the risk of wire breakage, reduces the use amount of the phase-shifting transformer insulation paper, and optimizes the transformer cost.
[0030] In the phase-shifting transformer 100 of the medium-voltage frequency converter 1000 according to the above-mentioned embodiments of the present application, the first-phase output terminal group area 121, the second-phase output terminal group area 122 and the third-phase output terminal group area 123 and the A, B and C three-phase can have the following multiple corresponding relationships shown in Table 1:
[0031] Table 1
[0032]
[0033] According to the above-mentioned embodiment of the medium voltage frequency converter 1000 of the power unit arrangement room 200, the first phase power unit 21, the second phase power unit 22 and the third phase power unit 23 can have a plurality of corresponding relationships with the A, B, C three-phase as shown in Table 2:
[0034] Table 2
[0035] First phase power unit 21 Second phase power unit 22 Third phase power unit 23 Correspondence 1 A-phase power unit B-phase power unit C-phase power unit Correspondence 2 A-phase power unit C-phase power unit B-phase power unit Correspondence 3 B-phase power unit A-phase power unit C-phase power unit Correspondence 4 B-phase power unit C-phase power unit A-phase power unit Correspondence 5 C-phase power unit B-phase power unit A-phase power unit Correspondence 6 C-phase power unit A-phase power unit B-phase power unit
[0036] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A phase-shifting transformer (100) comprising a plurality of primary-side input terminals (111), 3xn secondary-side output terminal groups (127) and a plurality of taps (131), n being an integer greater than or equal to 2, characterized in that: the phase-shifting transformer (100) has a first face (110) and a second face (120) arranged oppositely, the first face (110) of the phase-shifting transformer (100) has an input terminal area (11) arranged at a lower part, a tap area (13) arranged at an upper part, and an output terminal area (12) arranged between the input terminal area (11) and the tap area (13); the plurality of primary-side input terminals (111) are arranged in a horizontal direction in the input terminal area (11); the plurality of taps are arranged in a horizontal direction in the tap area (13); the 3xn secondary-side output terminal groups (127) are arranged in the output terminal area (12) in a vertical direction in a first-phase output terminal group area (121), a second-phase output terminal group area (122) and a third-phase output terminal group area (123), each of the first-phase output terminal group area (121), the second-phase output terminal group area (122) and the third-phase output terminal group area (123) has n secondary-side output terminal groups (127), and the n secondary-side output terminal groups (127) are arranged in a vertical direction in a first unit (125) and a second unit (126) arranged in a horizontal direction.
2. The phase shifting transformer (100) according to claim 1, characterized in that Each of the secondary-side output terminal groups (127) comprises three secondary-side output terminals (124) arranged in a horizontal direction.
3. The phase shifting transformer (100) of claim 1, characterized in that, The plurality of primary-side input terminals (111) comprises three primary-side input terminals (111) connected to three-phase input respectively.
4. The phase shifting transformer (100) of claim 1, characterized in that, The plurality of taps comprises a main tap, a positive tap and a negative tap.
5. The phase shifting transformer (100) of claim 1, characterized in that, The phase-shifting transformer (100) further comprises a plurality of current transformers (14) arranged in a horizontal direction between the tap area (13) and the output terminal area (12) on the first face (110) of the phase-shifting transformer (100).
6. The phase shifting transformer (100) of claim 5, characterized in that, The phase-shifting transformer (100) further comprises an auxiliary power supply winding (15) arranged between the plurality of current transformers (14) and the output terminal area (12) on the first face (110) of the phase-shifting transformer (100).
7. The phase shifting transformer (100) of claim 1, characterized in that, The first face (110) of the phase-shifting transformer (100) is a front face of a medium-voltage frequency converter (1000).
8. Medium voltage frequency converter (1000) comprising a phase-shift transformer (100) and a power cell arrangement chamber (200) located above the phase-shift transformer (100), the power cell arrangement chamber (200) being provided with 3 x 2n power cells, characterized in that, The phase-shifting transformer (100) is the phase-shifting transformer (100) of any one of claims 1-7, and each of the secondary-side output terminal groups (127) in the phase-shifting transformer (100) is connected in parallel to two power units.
9. Medium voltage frequency inverter (1000) according to claim 8, characterized in that The 3*2n power units include 2n first-phase power units (21) connected in series, 2n second-phase power units (22) connected in series, and 2n third-phase power units (23) connected in series, the 2n first-phase power units (21), the 2n second-phase power units (22), and the 2n third-phase power units (23) are connected in a star type, and each two power units in the 2n first-phase power units (21), the 2n second-phase power units (22), and the 2n third-phase power units (23) are respectively connected in parallel with one of the n secondary-side output terminal groups (127) in the first-phase output terminal group area (121), the second-phase output terminal group area (122), and the third-phase output terminal group area (123).
10. Medium voltage frequency inverter (1000) according to claim 9, characterized in that The power unit arrangement chamber (200) has a first face (210) and a second face (220) arranged oppositely, the first face (210) of the power unit arrangement chamber (200) is provided with a first-face first-layer arrangement area (211) and a first-face second-layer arrangement area (212) arranged longitudinally, and the second face (220) of the power unit arrangement chamber (200) is provided with a second-face first-layer arrangement area (221) and a second-face second-layer arrangement area (222) arranged longitudinally; At least part of the 2n first-phase power units (21) are arranged transversely in the first-face first-layer arrangement area (211), and a transverse first end of the first-face first-layer arrangement area (211) is used as a first-phase output end; At least part of the 2n second-phase power units (22) are arranged transversely in the first-face second-layer arrangement area (212), and a transverse first end of the first-face second-layer arrangement area (212) corresponding to the first-face first-layer arrangement area (211) is used as a second-phase output end; The 2n third-phase power units (23) are respectively arranged transversely on one side close to the transverse first end in the second-face first-layer arrangement area (221) and the second-face second-layer arrangement area (222) and are connected in series longitudinally in an interlaced manner, and a corresponding transverse first end of the second-face first-layer arrangement area (221) or the second-face second-layer arrangement area (222) is used as a third-phase output end; The rest of the 2n first-phase power units (21) in series and the rest of the 2n second-phase power units (22) in series are respectively arranged in the second-face first-layer arrangement area (221) and the second-face second-layer arrangement area (222) away from the side of the lateral first end, and one first-phase power unit (21) at the lateral second end in the first-face first-layer arrangement area (211) is electrically connected with one first-phase power unit (21) at the corresponding lateral second end in the second-face first-layer arrangement area (221), and one second-phase power unit (22) at the lateral second end in the first-face second-layer arrangement area (212) is electrically connected with one second-phase power unit (22) at the corresponding lateral second end in the second-face second-layer arrangement area (222).
11. Medium voltage frequency inverter (1000) according to claim 8, characterized in that The first face (210) of the power unit arrangement chamber (200) is the front face or the back face of the medium-voltage frequency converter (1000).