A reactor module, a doubly-fed power generation topology and a doubly-fed converter
By introducing reactor modules into the doubly fed generator topology, the problem of uneven current distribution in multiple grid-connected branches is solved, thereby improving the reliability and lifespan of the system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN HOPEWIND ELECTRIC CO LTD
- Filing Date
- 2025-07-30
- Publication Date
- 2026-07-31
AI Technical Summary
In high-power wind power converters, the direct parallel connection of multiple grid-connected branches leads to uneven current flow, affecting operational reliability and service life.
A reactor module is adopted, which includes multiple first reactors and a second reactor. These are connected in parallel to form a large impedance and connected in series between the grid-connected branch and the grid-side module unit to reduce the impact of impedance difference and achieve current sharing.
It improves the operational reliability and service life of the doubly-fed generator topology and doubly-fed converter, and suppresses the problem of uneven current flow.
Smart Images
Figure CN224582122U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power electronics technology, and in particular to a reactor module, a doubly fed generator topology, and a doubly fed converter. Background Technology
[0002] With the rapid development of new energy sources, the trend of developing high-power wind turbine generators is becoming increasingly apparent. In existing technologies, the design of high-power wind power converters often uses multiple grid-connected branches in parallel to increase unit capacity. When connecting in parallel, the output and input electrodes of multiple grid-connected branches are typically connected directly in parallel. However, in practical applications, it has been found that due to differences in the characteristics of components such as contactors in the grid-connected branches (e.g., impedance differences), the above-mentioned scheme of directly connecting multiple grid-connected branches in parallel leads to uneven current distribution among the branches. This results in excessive current in a single circuit, failing to meet derating requirements, affecting the reliability of the converter, and potentially impacting the lifespan of the components over long-term use. Utility Model Content
[0003] This utility model provides a reactor module, a doubly fed generator topology, and a doubly fed converter to solve the technical problem of uneven current distribution in multiple grid-connected branches caused by direct parallel connection of multiple grid-connected branches in high-power converters, which affects operational reliability and service life.
[0004] To address the aforementioned technical problems, in a first aspect, a reactor module is provided, comprising a plurality of first reactors and a second reactor, wherein one side of the plurality of first reactors is connected in parallel to one side of the second reactor, the other side of the plurality of first reactors serves as a first connection side of the reactor module, and the other side of the second reactor serves as a second connection side of the reactor module.
[0005] The further technical solution is as follows: both the first reactor and the second reactor are single-phase reactors or three-phase reactors.
[0006] To address the aforementioned technical problems, a third aspect provides a doubly-fed induction generator topology, comprising multiple grid-connected branches, a grid-side module unit, multiple generator-side module units, and the aforementioned reactor module, wherein...
[0007] One side of each of the multiple grid-connected branches is connected in parallel to the generator stator, and the other side is connected to the power grid through a corresponding transformer.
[0008] The AC side of the grid-side module unit is connected to the second connection side of the reactor module, and a first reactor in the first connection side of the reactor module is connected to a connection point of a grid-connected branch.
[0009] The DC side of the generator-side module unit is connected to the DC side of the grid-side module unit, and the AC side of the generator-side module unit is connected to the generator rotor.
[0010] The further technical solution is as follows: the doubly fed generator topology also includes multiple filter capacitor units, each of which is connected between a grid-connected branch and the generator stator.
[0011] The further technical solution is as follows: the grid-connected branch includes a frame circuit breaker and a grid-connected contactor, wherein the frame circuit breaker and the grid-connected contactor are connected in series, and their series connection point serves as the connection point of the grid-connected branch. The other side of the frame circuit breaker and the grid-connected contactor are respectively connected to the transformer and the generator stator.
[0012] The further technical solution is as follows: the doubly fed power generation topology also includes a fuse unit connected in series with the reactor module.
[0013] A further technical solution is as follows: the fuse unit is connected between the second connection side of the reactor module and the AC side of the grid-side module unit.
[0014] The further technical solution is as follows: the fuse unit is connected between the first connection side of the reactor module and the connection point of the grid-connected branch.
[0015] The further technical solution is as follows: the number of the grid-connected branch, the generator-side module unit, and the first reactor are all two. One side of each of the two first reactors is connected to the connection point of the two grid-connected branches, and the other side of each of the two first reactors is connected in parallel to the second reactor, so as to be connected to the AC side of the grid-side module unit through the second reactor. The DC side of each of the two generator-side modules and the DC side of the grid-side module unit are connected through a DC bus. The AC side of each of the two generator-side modules is connected to the generator rotor through a generator-side inductor.
[0016] To address the aforementioned technical problems, a third aspect provides a doubly-fed converter, including a controller and the aforementioned doubly-fed power generation topology, wherein the doubly-fed power generation topology is controlled by the controller.
[0017] Compared with the prior art, the reactor module of this utility model includes multiple first reactors and a second reactor. One end of the multiple first reactors is connected in parallel to one end of the second reactor. The other sides of the first reactors and the second reactor serve as the first connection side and the second connection side, respectively. When the reactor module is applied to a doubly-fed generator topology or a doubly-fed converter, the grid-side module unit in the doubly-fed generator topology or doubly-fed converter is connected to multiple grid-connected branches through the reactor module. That is, the AC side of the grid-side module unit and the connection point of the multiple grid-connected branches are respectively connected to the second connection side and the first connection side of the reactor module. Due to the current-limiting impedance characteristics of the reactor module, during use, it is equivalent to having a large impedance connected in series between the connection point of each grid-connected branch and the grid-side module unit, which greatly reduces the impact of impedance difference between the grid-side module unit and the multiple grid-connected branches. This is beneficial to the current sharing of multiple grid-connected branches and can improve the working reliability and service life of the doubly-fed generator topology or doubly-fed converter in which it is applied. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the structure of the first embodiment of the doubly fed power generation topology of this utility model.
[0019] Figure 2 This is a schematic diagram of the specific structure of the reactor module in the doubly fed generator topology shown in the first embodiment.
[0020] Figure 3 This is a schematic diagram of the second embodiment of the doubly fed power generation topology of this utility model.
[0021] Figure 4 This is a schematic diagram of the specific structure of the reactor module in the doubly fed generator topology shown in the first embodiment. Detailed Implementation
[0022] To better understand the technical content of this utility model, the technical solution of this utility model will be further introduced and explained below with reference to the schematic diagram, but it is not limited thereto.
[0023] Reference Figure 1 and Figure 2 , Figure 1 and Figure 2This paper presents a first embodiment of the doubly-fed generator topology of this invention. In the embodiment shown in the accompanying drawings, the doubly-fed generator topology includes two grid-connected branches (20A, 20B), a grid-side module unit 30, multiple generator-side module units 40, and a reactor module 10. One side of each of the multiple grid-connected branches (20A, 20B) is connected in parallel to the generator stator, and the other side is connected to the power grid via corresponding transformers. The connection point of the two grid-connected branches (20A, 20B) is connected to the AC side of the grid-side module unit 30 through the reactor module 10. The DC side of the grid-side module unit 30 is connected to the DC side of the generator-side module unit 40, and the AC side of the generator-side module unit 40 is connected to the generator rotor. This doubly-fed generator topology achieves power conversion through one grid-side module unit 30 and multiple generator-side module units 40; that is, multiple generator-side module units 40 are connected in parallel to perform generator-side power conversion, meeting power enhancement requirements. The grid-side module unit 30 handles the generator slip power. Understandably, there can be multiple grid-connected branches, and the number can be set according to the number of grid-connected cabinets in practical applications.
[0024] Preferably, in this embodiment, the reactor module 10 includes two first reactors (D1, D2) and a second reactor E. One side of the two first reactors (D1, D2) is connected in parallel to one side of the second reactor E. The other side of the two first reactors (D1, D2) serves as the first connection side of the reactor module 10, connecting to the connection points of two grid-connected branches (20A, 20B) respectively. The other side of the second reactor E serves as the second connection side of the reactor module 10, connecting to the AC side of the grid-side module unit 30, so that the grid-connected branches (20A, 20B) are connected to the grid-side module unit 30 through the reactor module 10. In practical applications, the first reactors (D1, D2) and the second reactor E in the reactor module 10 can be made as a single unit, sharing a reactor core to reduce volume, or they can each be an independent reactor. Based on the above design, the inductance value of the reactor module 10 is relatively large. When the connection point of the grid-connected branch (20A, 20B) is connected to the AC side of the grid-side module unit 30 through the reactor module 10, it is equivalent to connecting a large impedance in series between the grid-connected branch (20A, 20B) and the grid-side module unit 30. This reduces the uneven current in the two grid-connected circuits caused by the impedance difference of the devices (such as grid-connected contactors) in the grid-connected branch (20A, 20B), which helps to suppress the current sharing problem between the grid-side module unit 30 and the grid-connected branch (20A, 20B).
[0025] Specifically, such as Figure 2As shown, in this embodiment, the power grid is a single-phase power grid, the first reactor (D1, D2) and the second reactor E are both single-phase reactors, and the number of the generator-side module units 40 is two. The DC side of the two generator-side module units 40 and the DC side of the grid-side module unit 30 are connected through a DC bus. A corresponding bus capacitor C is connected between the positive and negative poles of the DC bus, and the AC side of the two generator-side module units 40 are respectively connected to the generator rotor through generator-side inductors L.
[0026] In some embodiments, the grid-connected branch includes a frame circuit breaker and a grid-connected contactor connected in series with the frame circuit breaker, such as... Figure 1 As shown, grid-connected branch 20A includes a frame circuit breaker QA and a grid-connected contactor KA. The series connection point YA of the frame circuit breaker QA and the grid-connected contactor KA is the connection point of the grid-connected branch 20A. Grid-connected branch 20B includes a frame circuit breaker QB and a grid-connected contactor KB. The series connection point YB of the frame circuit breaker QB and the grid-connected contactor KB is the connection point of the grid-connected branch 20B. The other side of the frame circuit breaker (QA, QB) is connected to the corresponding transformer, that is, connected to the power grid transformer side. The other side of the grid-connected contactor (KA, KB) is connected to the generator stator. Understandably, during power generation operation, i.e., when both the frame circuit breakers (QA, QB) and the grid-connected contactors (KA, KB) are closed, if each grid-connected branch (20A, 20B) is connected to the grid-side module unit 30 by cables, the equivalent impedance is small and is greatly affected by the contact impedance of the contactors (KA, KB) and the cable impedance. The two are mismatched, which easily leads to uneven current distribution. In this invention, a reactor module 10 with a first reactor (D1, D2) and a second reactor E is added between the grid-connected branch (20A, 20B) and the grid-side module unit 30. This is equivalent to inserting a large impedance in series between the series connection point of the frame circuit breakers (QA, QB) and the grid-connected contactors (KA, KB), which can act as a current-limiting impedance, thereby suppressing the uneven current distribution of the load on the grid-connected contactors (KA, KB), and also has a filtering function.
[0027] Furthermore, in some embodiments, the doubly-fed generator topology further includes two filter capacitor units, each of which is connected between one of the grid-connected branches and the generator stator. Specifically, as shown... Figure 1 As shown, one of the filter capacitor units includes a filter capacitor C1, and the other filter capacitor unit includes a filter capacitor C2. One end of the filter capacitor C1 is connected between the grid-connected branch 20A and the generator stator, and one end of the filter capacitor C2 is connected between the grid-connected branch 20B and the generator stator. The other ends of both filter capacitors C1 and C2 are grounded.
[0028] In some embodiments, the doubly-fed power generation topology further includes a fuse unit connected in series with the reactor module 10, such as... Figure 1As shown, the fuse unit includes a protective fuse FU1, which is connected between the second connection side of the reactor module 10 and the AC side of the grid-side module unit 30. It can be understood that in some other embodiments, the fuse unit may also be connected between the first connection side of the reactor module 10 and the connection point of the grid-connected branch (20A, 20B). In this case, the number of protective fuses FU1 in the fuse unit can be set according to the number of the first reactors (D1, D2).
[0029] As can be seen from the above, this utility model connects a reactor module 10 with a large inductance value between the grid-connected branch (20A, 20B) and the grid-side module unit 30. That is, a large impedance is connected in series between each grid-connected branch (20A, 20B) and the grid-side module unit 30, thereby reducing the uneven current of multiple grid-connected circuits caused by the impedance difference of the devices in the grid-connected branch (20A, 20B). This helps to suppress the current sharing problem between the grid-side module unit 30 and each grid-connected branch (20A, 20B), and improves the working reliability and service life of the doubly-fed generator topology.
[0030] Reference Figure 3 and Figure 4 , Figure 3 and Figure 4 This paper presents a second embodiment of the doubly-fed generator topology of this invention. The difference between this embodiment and the first embodiment is that the power grid in this embodiment is a three-phase power grid. The first reactor (D1, D2) and the second reactor E in the reactor module 10 are both three-phase reactors. Correspondingly, the filter capacitor is a three-phase capacitor, and the remaining structures are the same or similar. Figure 3 and Figure 4In this embodiment, A1, B1, and C1 of the first reactor D1 are connected to the three phases of the AC circuit of the grid-connected branch 20A, and A2, B2, and C2 of the first reactor D2 are connected to the three phases of the AC circuit of the grid-connected branch 20B. A, B, and C of the second reactor E are respectively used to connect to the AC side of the grid-side module unit 30. A1 and A2 are connected in parallel with one of the grid-connected contactors KA and KB, respectively. The inductance between A1 and A2 and A2 together constitutes the filter reactance of phase A of the grid-side module unit 30. B1 and B2 are also connected in parallel with one of the grid-connected contactors KA and KB, respectively. The inductance between B1 and B2 together constitutes the filter reactance of phase A of the grid-side module unit 30. The filter reactance of phase B of the grid-side module unit 30, consisting of C1 and C2, is connected in parallel with one of the grid-connected contactors KA and KB, respectively. The inductance between C1 and C2 together constitutes the filter reactance of phase C of the grid-side module unit 30, which increases the impedance between the grid-connected branches (20A, 20B) and the grid-side module unit 30. This can act as a current-limiting impedance, greatly reducing the impact of impedance differences between the grid-side module unit 30 and the multiple grid-connected branches (20A, 20B), thereby suppressing the uneven current distribution of the load on the grid-connected contactors (KA, KB), and thus improving the operational reliability and service life of the doubly-fed generator topology.
[0031] Understandably, this utility model can also provide a doubly-fed converter, which includes a controller and the doubly-fed power generation topology described in the first or second embodiment above. The doubly-fed converter can be a doubly-fed wind power converter, etc. Power conversion is achieved through a grid-side module unit 30 and multiple generator-side module units 40. A reactor module 10 is connected between the connection point of the grid-connected branches (20A, 20B) and the grid-side module unit 30. The reactor module 10 of this utility model not only performs filtering functions but also functions as a current-limiting impedance, weakening the impedance difference between the grid-side module unit 30 and the multiple grid-connected branches (20A, 20B), thereby suppressing the uneven current in the multiple grid-connected branches (20A, 20B), and thus improving the working reliability and service life of the doubly-fed converter.
[0032] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.
Claims
1. A reactor module, characterized by The reactor module includes a plurality of first reactors and a second reactor, wherein one side of the plurality of first reactors is connected in parallel to one side of the second reactor, the other side of the plurality of first reactors serves as the first connection side of the reactor module, and the other side of the second reactor serves as the second connection side of the reactor module.
2. The reactor module of claim 1, wherein, Both the first reactor and the second reactor are single-phase reactors or three-phase reactors.
3. A doubly-fed power generation topology, characterized by, The doubly-fed power generation topology includes multiple grid-connected branches, a grid-side module unit, multiple generator-side module units, and the reactor module described in any one of claims 1-2, wherein... One side of each of the multiple grid-connected branches is connected in parallel to the generator stator, and the other side is connected to the power grid through a corresponding transformer. The AC side of the grid-side module unit is connected to the second connection side of the reactor module, and a first reactor in the first connection side of the reactor module is connected to a connection point of a grid-connected branch. The DC side of the generator-side module unit is connected to the DC side of the grid-side module unit, and the AC side of the generator-side module unit is connected to the generator rotor.
4. The doubly-fed power generation topology of claim 3, wherein, The doubly fed generator topology also includes multiple filter capacitor units, each of which is connected between a grid-connected branch and the generator stator.
5. A doubly-fed power generation topology as claimed in claim 3 or 4, characterized in that, The grid-connected branch includes a frame circuit breaker and a grid-connected contactor, wherein the frame circuit breaker and the grid-connected contactor are connected in series, and their series connection point serves as the connection point of the grid-connected branch. The other side of the frame circuit breaker and the grid-connected contactor are respectively connected to the transformer and the generator stator.
6. A doubly-fed power generation topology as claimed in claim 3 or 4, characterized in that, The doubly fed generator topology also includes a fuse unit connected in series with the reactor module.
7. The doubly-fed power generation topology of claim 6, wherein, The fuse unit is connected between the second connection side of the reactor module and the AC side of the grid-side module unit.
8. The doubly-fed power generation topology of claim 6, wherein, The fuse unit is connected between the first connection side of the reactor module and the connection point of the grid-connected branch.
9. A doubly-fed power generation topology as claimed in claim 3 or 4, characterized in that, The number of the grid-connected branch, the generator-side module unit, and the first reactor are all two. One side of each of the two first reactors is connected to the connection point of the two grid-connected branches, and the other side of each of the two first reactors is connected in parallel to the second reactor, so as to be connected to the AC side of the grid-side module unit through the second reactor. The DC side of each of the two generator-side modules and the DC side of the grid-side module unit are connected through a DC bus. The AC side of each of the two generator-side modules is connected to the generator rotor through a generator-side inductor.
10. A double-fed current converter, characterized in that It includes a controller and the doubly-fed power generation topology as described in any one of claims 3-9, wherein the doubly-fed power generation topology is controlled by the controller.