Converter and double-fed wind power generation system

Abstract

The utility model provides a converter and a double-fed wind power generation system. The input end of the converter is connected with the transformer, and the output end of the converter is connected with the doubly-fed motor; wherein a stator loop of the converter is provided with a stator filter, and a rotor loop of the converter is provided with a network side filter, a converter module and a machine side filter which are connected in sequence. The converter is used for enhancing the harmonic filtering effect and reducing the total outlet harmonic content of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to power generation technology, in particular to a converter and a doubly-fed wind power generation system. BACKGROUND

[0002] Wind power generation refers to converting the kinetic energy of wind into electric energy. In a wind power generation system, a doubly-fed wind power generation system has a higher and higher proportion in the wind power market due to its small capacity and low cost. During the operation of the doubly-fed wind power generation system, the existence of harmonics will bring great negative effects, including reducing power quality, shortening equipment life, obvious noise and vibration, etc., so how to filter out harmonics is crucial.

[0003] In the prior art, a filter is designed on the grid side and the machine side of the converter of the doubly-fed wind power generation system to filter out harmonics, but the filtering effect is limited, which often leads to excessive harmonic content of the system total outlet. CONTENT OF THE UTILITY MODEL

[0004] The present application provides a converter and a doubly-fed wind power generation system to enhance the harmonic filtering effect and reduce the harmonic content of the system total outlet.

[0005] In one aspect, the present application provides a converter, the input end of the converter is connected with a transformer, and the output end of the converter is connected with a doubly-fed motor; wherein,

[0006] The stator circuit of the converter is provided with a stator filter, and the rotor circuit of the converter is provided with a grid-side filter, a converter module and a machine-side filter connected in sequence.

[0007] In one possible implementation, the number of stator filters is multiple, and the multiple stator filters are connected in parallel.

[0008] In one possible implementation, the stator filter comprises a first reactor and a first capacitor group; one end of the first reactor is connected to the stator circuit, and the other end of the first reactor is connected with the first capacitor group; the first capacitor group adopts a delta connection or a star connection.

[0009] In one possible implementation, the number of first capacitor groups is multiple, and the multiple first capacitor groups are connected in parallel.

[0010] In one possible implementation, the stator filter further comprises a first resistor; wherein,

[0011] One end of the first resistor is connected to the stator circuit, and the other end of the first resistor is connected with one end of the first reactor.

[0012] Alternatively, the other end of the first reactor is connected to one end of the first resistor, and the other end of the first resistor is connected to the first capacitor bank.

[0013] In a possible implementation, the stator filter further includes a fuse; one end of the fuse is connected to the stator circuit, and the other end of the fuse is connected to one end of the first reactor.

[0014] In a possible implementation, the stator circuit is further provided with a stator contactor; the stator filter is located in front of or behind the stator contactor.

[0015] In a possible implementation, when the stator filter is located in front of the stator contactor, the stator filter further includes a first contactor; one end of the first contactor is connected to the fuse, and the other end of the first contactor is connected to one end of the first reactor.

[0016] In a possible implementation, the grid-side filter includes a second reactor and a second capacitor bank.

[0017] One end of the second reactor is connected to the input end of the converter, and the other end of the second reactor is connected to one end of the second capacitor bank and the converter module.

[0018] In a possible implementation, the grid-side filter includes a second reactor and a second capacitor bank; the stator circuit is further provided with a third capacitor bank; the capacity of the second capacitor bank is smaller than the capacity of the third capacitor bank.

[0019] One end of the second reactor is connected to the input end of the converter, and the other end of the second reactor is connected to one end of the second capacitor bank and the converter module.

[0020] In a possible implementation, the grid-side filter includes a second reactor; the stator circuit is further provided with a third capacitor bank.

[0021] One end of the second reactor is connected to the input end of the converter, and the other end of the second reactor is connected to the converter module.

[0022] In another aspect, the embodiments of the present application provide a doubly-fed wind power generation system, including a transformer, a doubly-fed motor, and a converter as described above.

[0023] The converter and the double-fed wind power generation system provided by the application have the grid-side filter and the machine-side filter connected in sequence arranged in the rotor loop of the converter, which can effectively filter out the rotor loop harmonics and can improve the power quality to a certain extent; the stator filter is arranged in the stator loop of the converter, which can effectively filter out the stator loop harmonics and can filter out the harmonics of a specific frequency, improve the filtering effect, avoid the stator loop harmonics or the harmonics of a specific frequency exceeding the standard, effectively reduce the total outlet harmonic content, and thus reduce the design complexity and cost of the grid-side filter and the machine-side filter while meeting the power quality requirements. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and serve to explain the principles of the application.

[0025] Figure 1 Fig. 1 exemplarily shows a structure schematic diagram of a converter provided by an embodiment of the application;

[0026] Figure 2 Fig. 2 exemplarily shows a structure schematic diagram of another converter provided by an embodiment of the application;

[0027] Figure 3 Fig. 3 exemplarily shows a structure schematic diagram of still another converter provided by an embodiment of the application;

[0028] Figure 4 Fig. 4 exemplarily shows a structure schematic diagram of still another converter provided by an embodiment of the application;

[0029] Figure 5 Fig. 5 exemplarily shows a structure schematic diagram of still another converter provided by an embodiment of the application;

[0030] Figure 6 Fig. 6 exemplarily shows a structure schematic diagram of still another converter provided by an embodiment of the application;

[0031] Figure 7 Fig. 7 exemplarily shows a structure schematic diagram of still another converter provided by an embodiment of the application;

[0032] Figure 8 Fig. 8 exemplarily shows a structure schematic diagram of still another converter provided by an embodiment of the application;

[0033] Figure 9 Fig. 9 exemplarily shows a structure schematic diagram of still another converter provided by an embodiment of the application.

[0034] The specific embodiments of the application have been shown by the above drawings, and will be described in more detail hereinafter. These drawings and detailed description are not intended to limit the scope of the concept of the application in any way, but to illustrate the concept of the application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0035] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The following description is made with reference to the accompanying drawings in which like reference numerals represent like elements, unless the context of use indicates otherwise. The following description of exemplary embodiments is not representative of all embodiments consistent with the present application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the present application as detailed in the appended claims.

[0036] The module in the present application refers to a functional module or a logical module. It can be in the form of software, and its function is realized by executing program code by a processor; or it can be in the form of hardware. The "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the three cases of A alone, A and B together, and B alone. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0037] First, the terms related to the embodiments of the present application are explained.

[0038] CL filter: a filter circuit designed by combining inductance (L) and capacitance (C), which can filter harmonics, has simple structure and low cost, and can effectively attenuate high-frequency harmonic components of output voltage.

[0039] LCL filter: a filter circuit designed by combining inductance (L) and capacitance (C), including input inductance, parallel capacitance and output inductance, which can filter harmonics and effectively attenuate high-frequency harmonic components.

[0040] LRC filter: a filter circuit designed by combining inductance (L), resistance (R) and capacitance (C).

[0041] Wind power generation refers to converting the kinetic energy of wind into electric energy. In a wind power generation system, a doubly-fed wind power generation system has a higher and higher proportion in the wind power market due to its small capacity and low cost. During the operation of the doubly-fed wind power generation system, the existence of harmonics will bring great negative effects, including reducing power quality, shortening equipment life, obvious noise and vibration, etc., so how to filter out harmonics is crucial.

[0042] In the prior art, filters are usually designed on the grid side and the machine side of the converter module of the doubly-fed wind power generation system to filter out harmonics, but the filtering effect is limited, and the total harmonic content of the system outlet often exceeds the standard.

[0043] To solve the above technical problems, the embodiment of the present application provides a converter for a doubly-fed wind power generation system. For the doubly-fed power generation system, the power quality of the total grid power of the rotor loop and the stator loop is checked, and the grid side filter and the machine side filter can filter out the harmonics at the outlet of the converter module, which can improve the power quality of the grid side to a certain extent. However, if the harmonics generated by the stator loop or the harmonics of a certain frequency exceed the standard, a filter can be added to the stator loop of the converter, which can not only reduce the harmonic content of the grid, but also effectively reduce the design cost and difficulty of the rotor loop filter.

[0044] The technical solutions of the present application will be described below with specific examples. The following specific examples can be combined with each other, and the same or similar concepts or processes can not be described in detail in some examples.

[0045] Figure 1 A structure diagram of a converter provided by the embodiment of the present application is shown in FIG. 1. Figure 1 As shown in the figure, the converter 100 includes: a connection between the input end of the converter and the transformer T, and a connection between the output end of the converter and the doubly-fed motor M; wherein,

[0046] The stator loop of the converter 100 is provided with a stator filter 11, and the rotor loop of the converter 100 is provided with a grid side filter 12, a converter module 13 and a machine side filter 14 connected in sequence.

[0047] In a specific implementation, the rotor loop of the converter 100 is provided with the converter module 13, which is used to add a controllable three-phase alternating voltage to the rotor three-phase winding, so that the rotor current is controlled, thereby interacting with the rotating magnetic field generated by the stator to control the power transmitted by the stator winding to the grid. When the rotor speed changes, the amplitude, phase, frequency, etc. of the excitation current can be controlled through the converter module 13, so that the stator loop can input constant frequency power to the grid. The grid side of the converter module 13 is provided with a grid side filter 12 to filter out high-frequency harmonics on the grid side and convert the switching pulse square wave into continuous analog quantity; the machine side of the converter module 13 is provided with a machine side filter 14 to filter out the switching pulse square wave into a sine wave and suppress high-frequency harmonics. Through the grid side filter 12 and the machine side filter 14, the rotor loop harmonics of the doubly-fed wind power generation system can be filtered out.

[0048] The stator circuit of the converter 100 not only contains the rotor circuit harmonics coupled to the stator circuit through the air gap magnetic field, but also contains the slot harmonics introduced by the doubly-fed motor and the high-order harmonics in the air gap magnetic field. For the doubly-fed wind power generation system, the power quality of the total power output to the grid (for example, the total harmonic distortion rate) of the rotor circuit and the stator circuit is examined, and therefore, when the stator harmonic is excessively large, especially when the transformer T is a three-winding box-type transformer, the total outlet harmonic content of the system is likely to exceed the standard. Therefore, by arranging the stator filter 11 in the stator circuit, the stator circuit harmonics can be effectively filtered out, the total outlet harmonic content of the system can be effectively reduced, and the power quality requirement can be met.

[0049] It can be understood that the rotor circuit harmonic content in the system is greater than the stator circuit harmonic content, and therefore, the filter arranged only in the rotor circuit can also meet the power quality requirement, but the filtering requirement of the filter is high, which leads to complex filter design and high cost. By arranging the filter in the stator circuit and filtering out the stator circuit harmonics to meet the power quality requirement, the filtering requirement of the rotor circuit filter can be effectively reduced, thereby reducing the design complexity and cost of the rotor circuit filter. Further, some regions or countries may have requirements for the content of specific frequency harmonics at the total outlet, and the specific frequency harmonics can be filtered out by the stator circuit filter to meet the power quality requirement.

[0050] In the embodiment of the present application, the grid-side filter and the machine-side filter connected in sequence are arranged in the rotor circuit of the converter 100, which can effectively filter out the rotor circuit harmonics; the stator filter is arranged in the stator circuit of the converter 100, which can effectively filter out the stator circuit harmonics and can filter out specific frequency harmonics, thereby improving the filtering effect, reducing the design complexity and cost of the grid-side filter and the machine-side filter, and meeting the power quality requirement.

[0051] Figure 2 Another structure schematic diagram of a converter is provided in the embodiment of the present application. As shown in Figure 2 In a possible implementation manner, the number of stator filters 11 is multiple, and the multiple stator filters 11 are connected in parallel.

[0052] In a specific implementation, each stator filter 11 can be used to filter out a specific frequency harmonic in the stator circuit. According to the actual power quality requirement, N groups (N≥1) of parallel stator filters 11 can be arranged, and different stator filters 11 can be used to filter out different specific frequency harmonics, thereby realizing multi-frequency harmonic filtering and meeting the power quality requirement while reducing the cost to the greatest extent.

[0053] It should be noted that, Figure 2The number of stator filters 11 is only taken as an example for description, and the number of stator filters 11 can be selected according to the production needs in actual application, and the number of stator filters 11 is not limited herein.

[0054] As shown in Figure 1 , Figure 2 in a possible implementation, the stator filter 11 includes: a first reactor L1 and a first capacitor group C1; one end of the first reactor L1 is connected to the stator circuit, and the other end of the first reactor L1 is connected with the first capacitor group C1; the first capacitor group C1 adopts a delta connection or a star connection.

[0055] In a specific implementation, the first reactor L1 and the first capacitor group C1 in series constitute a CL filter or an LC filter, which can effectively filter the stator circuit harmonics. The first reactor L1 can be a three-phase reactor, and the first reactor L1 can adopt water cooling, air cooling or other cooling methods, and the cooling method is not limited herein.

[0056] It should be noted that the first capacitor group C1 adopts a delta connection or a star connection, and the like, Figure 1 , Figure 2 only a delta connection is taken as an example for description, and the delta connection does not constitute a limitation on the specific implementation of the embodiments of the present application.

[0057] Figure 3 Another structure diagram of a converter provided by the embodiments of the present application is shown in Figure 3 in a possible implementation, the number of the first capacitor group C1 is multiple, and the multiple first capacitor groups C1 are connected in parallel.

[0058] In a specific implementation, multiple parallel first capacitor groups C1 can be set according to the filtering needs, and one end of each of the multiple first capacitor groups C1 is connected to the first reactor L1. In actual application, each first capacitor group C1 can be connected to the first reactor L1 individually, or multiple first capacitor groups C1 can be designed as multiple capacitor modules to realize unit design; the multiple parallel first capacitor groups C1 can be directly connected to the first reactor L1, or can be connected to the first reactor L1 through copper bars or cables.

[0059] Figure 4 Another structure diagram of a converter provided by the embodiments of the present application is shown in Figure 5 Another structure diagram of a converter provided by the embodiments of the present application is shown in Figure 4 and Figure 5 in a possible implementation, the stator filter 11 further includes: a first resistor R1; wherein,

[0060] One end of the first resistor R1 is connected to the stator circuit, and the other end of the first resistor R1 and one end of the first reactor L1 are connected.

[0061] Alternatively, the other end of the first reactor L1 and one end of the first resistor R1 are connected, and the other end of the first resistor R1 and the first capacitor group C1 are connected.

[0062] In a specific implementation, if the filter resonance peak is too large, the resonance peak can also be reduced by connecting the first resistor R1 in series in the stator filter 11. The first resistor R1, the first reactor L1, and the first capacitor group C1 constitute an LRC filter, which can effectively filter out harmonics.

[0063] As shown in FIG. 1, Figure 4 The first resistor R1 can be arranged between the stator circuit and the first reactor L1 (the front stage of the first reactor L1). As shown in FIG. 1, Figure 5 The first resistor R1 can also be arranged between the first reactor L1 and the first capacitor group C1 (the rear stage of the first reactor L1).

[0064] Figure 6 Another structure diagram of a converter provided by an embodiment of the present application is shown in FIG. 2. As shown in FIG. 2, Figure 6 When the number of the first capacitor groups C1 is N (N≥1), the number of the first resistors R1 can be n (1≤n≤N), and each first resistor R1 is connected in series between one first capacitor group C1 and the first reactor L1. That is, for the plurality of parallel first capacitor groups C1, at least one first capacitor group C1 and the first reactor L1 are connected in series with the first resistor R1.

[0065] As shown in FIG. 1, Figures 1-6 In a possible implementation, the stator filter 11 further includes a fuse FU1. One end of the fuse FU1 is connected to the stator circuit, and the other end of the fuse FU1 and one end of the first reactor L1 are connected.

[0066] In a specific implementation, the fuse FU1 can be arranged in the front stage of the first reactor L1, so as to be fused when the stator filter 11 fails (for example, short-circuit), effectively protecting the system and improving the reliability of the system.

[0067] As shown in FIG. 1, Figures 1-6 In a possible implementation, the stator circuit further includes a stator contactor K. The stator filter 11 is arranged in the front stage or the rear stage of the stator contactor K.

[0068] In a specific implementation, a circuit breaker Q is arranged in the converter for protecting the circuit, and has an automatic breaking function. A stator contactor K is arranged at the rear stage of the circuit breaker Q, for controlling the conduction or disconnection of the stator circuit, thereby controlling the grid connection or disconnection of the doubly-fed motor M. The position of the stator filter 11 can be flexibly selected according to actual needs, and can adapt to the needs of different scenarios. For example, as shown in Figures 1-6 , the stator filter 11 can be arranged at the front stage of the stator contactor K. Figure 7 Another structure diagram of a converter provided by an embodiment of the present application is shown in Figure 7 , the stator filter 11 can also be arranged at the rear stage of the stator contactor K.

[0069] As shown in Figures 1-6 , in a possible implementation, when the stator filter 11 is located at the front stage of the stator contactor K, the stator filter 11 further includes a first contactor K1, one end of the first contactor K1 is connected with a fuse FU1, and the other end of the first contactor K1 is connected with one end of a first reactor L1.

[0070] In a specific implementation, when the stator filter 11 is located at the front stage of the stator contactor K, a first contactor K1 can be arranged in the stator filter 11. When the stator contactor K is disconnected, the doubly-fed motor M is disconnected from the grid, and at this time, the first contactor K1 is disconnected, thereby avoiding the stator filter 11 and the grid from exchanging reactive power.

[0071] As shown in Figure 7 , when the stator filter 11 is located at the rear stage of the stator contactor K, when the stator contactor K is disconnected, the doubly-fed motor M is disconnected from the grid, and at this time, the stator filter 11 no longer exchanges reactive power with the grid, so that the first contactor K1 is not needed, which not only saves the cost of arranging the first contactor K1, but also reduces the failure rate of the branch where the stator filter 11 is located.

[0072] As shown in Figures 1-7 , in a possible implementation, the grid-side filter 12 includes a second reactor L2 and a second capacitor group C2.

[0073] One end of the second reactor L2 is connected with the transformer T, and the other end of the second reactor L2 is connected with one end of the second capacitor group C2 and the variable flow module 13.

[0074] In a specific implementation, the second reactor L2 and the second capacitor bank C2 form a CL filter, which can filter out the grid-side switching frequency harmonics. Further, the second reactor L2 and the current conversion module 13 can be further connected in series with a third reactor L3. The second reactor L2, the third reactor L3 and the second capacitor bank C2 form an LCL filter, which can filter out harmonics while effectively suppressing resonance. Similarly, the second capacitor bank C2 can adopt a delta connection or a star connection, and the like, which is not limited herein.

[0075] In a possible implementation, the transformer T is a three-winding box-type transformer or a double-winding box-type transformer.

[0076] In a specific implementation, as shown in Figures 1-7 , the transformer T is a three-winding box-type transformer. Figure 8 Another structure diagram of a current converter is provided for the embodiments of the present application. As shown in Figure 8 , when the transformer T is a double-winding box-type transformer, the circuit breaker Q can be a total circuit breaker of the stator circuit and the rotor circuit.

[0077] In actual applications, the type of the transformer T can be flexibly selected as needed, which can be applicable to various scenarios and effectively improve the flexibility and adaptability of the system.

[0078] As shown in Figures 1-8 , in a possible implementation, the grid-side filter 12 includes a second reactor L2 and a second capacitor bank C2.

[0079] One end of the second reactor L2 is connected to the input end of the current converter 100, and the other end of the second reactor L2 is connected to one end of the second capacitor bank C2 and the current conversion module 13.

[0080] In a specific implementation, the second reactor L2 and the second capacitor bank C2 form an LC filter, which can filter out high-frequency harmonics at the grid side and convert the switching pulse square wave into continuous analog quantities. Further, the second reactor L2 and the current conversion module 13 can be further connected in series with a third reactor L3. The second reactor L2, the third reactor L3 and the second capacitor bank C2 form an LCL filter.

[0081] Figure 9 Another structure diagram of a double-fed wind power generation system is provided for the embodiments of the present application. As shown in Figure 9 , in a possible implementation, the grid-side filter 12 includes a second reactor L2; and the stator circuit further includes a third capacitor bank C4.

[0082] In a specific implementation, the grid-side filter 12 can only set the second reactor L2, and set the third capacitor bank C4 in the stator loop. The soft start loop in the rotor loop (grid side) can be set, and the soft start loop includes the second resistor R2, the protection switch Q2, the second contactor K2, and the third contactor K3. One end of the protection switch Q2 is connected with the circuit breaker Q and one end of the third contactor K3, and the other end of the protection switch Q2 is connected with one end of the second contactor K2. The other end of the second contactor K2 is connected with one end of the second resistor R2, and the other end of the third contactor K3 is connected with the second reactor L2. By setting the third capacitor bank C4 in the stator loop, the second capacitor bank C2 can not be set in the rotor loop, so that the selection of the soft start loop does not need to consider the second capacitor bank C2, the selection pressure is reduced, and the reactive power is preferentially sent by the stator loop, so that the capacity of the grid-side module and the selection pressure of the switch in the grid-side loop can be reduced.

[0083] It should be noted that, Figure 9 Only the case that the second capacitor bank C2 is located at the rear stage of the stator contactor K is taken as an example for description. In actual application, the second capacitor bank C2 can also be located at the front stage of the stator contactor K, and a contactor needs to be connected in series between the second capacitor bank C2 and the rotor loop.

[0084] In a possible implementation, the grid-side filter 12 includes the second reactor L2 and the second capacitor bank C2; the stator loop further includes the third capacitor bank C4; the capacity of the second capacitor bank C2 is less than the capacity of the third capacitor bank C4.

[0085] One end of the second reactor C2 is connected with the transformer T, and the other end of the second reactor C2 is connected with one end of the second capacitor bank and the current conversion module 13.

[0086] In a specific implementation, the third capacitor bank C4 can also be set in the rotor loop, and the capacity of the third capacitor bank C4 is greater than the capacity of the second capacitor bank C2, so that better filtering effect can be achieved while the capacity of the grid-side module and the selection pressure of the switch in the grid-side loop are reduced, and the reactive power is preferentially sent by the stator loop.

[0087] In a possible implementation, the machine-side filter 14 is an LRC filter.

[0088] As Figures 1-9As shown, the machine side filter 14 can include a fourth reactor L4, a third resistor R3 and a fourth capacitor C3, one end of the fourth reactor L4 is connected with the current conversion module 13, the other end of the fourth reactor L4 is connected with one end of the third resistor R3 and the doubly-fed motor M, the other end of the third resistor R3 is connected with the fourth capacitor C3. The fourth reactor L4, the third resistor R3 and the fourth capacitor C3 constitute an LRC filter, which can effectively filter the switching pulse square wave into a sine wave and suppress high frequency harmonics.

[0089] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0090] It is to be understood that the application is not limited to the precise details of construction and the above-described and shown exact structure, and that various modifications and changes can be applied to it without departing from the scope of the application. The scope of the application is to be limited only by the appended claims.

Claims

1. A converter, characterized in that, The input terminal of the converter is connected to the transformer, and the output terminal of the converter is connected to the doubly-fed induction generator; wherein... The stator circuit of the converter is equipped with a stator filter, and the rotor circuit of the converter is equipped with a grid-side filter, a converter module and a machine-side filter connected in sequence.

2. The converter according to claim 1, characterized in that, The stator filters are multiple, and these multiple stator filters are connected in parallel.

3. The converter according to claim 1, characterized in that, The stator filter includes a first reactor and a first capacitor bank; one end of the first reactor is connected to the stator circuit, and the other end of the first reactor is connected to the first capacitor bank; the first capacitor bank is connected in a delta or star configuration.

4. The converter according to claim 3, characterized in that, There are multiple first capacitor banks connected in parallel.

5. The converter according to claim 4, characterized in that, The stator filter further includes: a first resistor; wherein... One end of the first resistor is connected to the stator circuit, and the other end of the first resistor is connected to one end of the first reactor. Alternatively, one end of the first reactor is connected to one end of the first resistor, and the other end of the first resistor is connected to the first capacitor bank.

6. The converter according to claim 3, characterized in that, The stator filter further includes a fuse; one end of the fuse is connected to the stator circuit, and the other end of the fuse is connected to one end of the first reactor.

7. The converter according to claim 6, characterized in that, The stator circuit is further provided with: a stator contactor; the stator filter is located before or after the stator contactor.

8. The converter according to claim 7, characterized in that, When the stator filter is located before the stator contactor, the stator filter further includes: a first contactor; one end of the first contactor is connected to the fuse, and the other end of the first contactor is connected to one end of the first reactor.

9. The converter according to claim 1, characterized in that, The grid-side filter includes a second reactor and a second capacitor bank; One end of the second reactor is connected to the input terminal of the converter, and the other end of the second reactor and one end of the second capacitor bank are connected to the converter module.

10. The converter according to claim 1, characterized in that, The grid-side filter includes a second reactor and a second capacitor bank; the stator circuit is also provided with a third capacitor bank; the capacity of the second capacitor bank is smaller than the capacity of the third capacitor bank. One end of the second reactor is connected to the input terminal of the converter, and the other end of the second reactor and one end of the second capacitor bank are connected to the converter module.

11. The converter according to claim 1, characterized in that, The grid-side filter includes a second reactor; the stator circuit is also provided with a third capacitor bank; One end of the second reactor is connected to the input terminal of the converter, and the other end of the second reactor is connected to the converter module.

12. A doubly-fed wind power generation system, characterized in that, include: Transformer, doubly fed motor, and converter as described in any one of claims 1-11.

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