Filtering loop in doubly-fed converter and control method thereof

Abstract

The invention discloses a filtering loop in a doubly-fed converter and a control method thereof, and the filtering loop comprises a main power supply loop which comprises an AC side and a generator, the generator is provided with a stator end and a rotor end, and the AC side is used for connecting the generator with a power grid; the filtering loop is arranged at the stator end of the generator, is connected with the alternating current side and the analog quantity board and is used for rectifying and filtering; the analog quantity board is connected with the filtering loop and used for controlling the whole system; wherein the filtering loop is provided with a plurality of current transformers A which are connected in parallel; moreover, each phase of current of the filtering loop is connected with a copper bar, the copper bar is connected with a filtering circuit, and the filtering circuit is provided with a filtering capacitor. The filter circuit is also provided with a filter bypass, and the filter bypass is provided with a discharge resistor. A filtering loop in the doubly-fed converter is provided with a plurality of groups of filtering capacitors, so that harmonic waves are filtered, voltage is stabilized, interference is suppressed, and interference on a power grid side and an electric generator side is reduced; and meanwhile, a discharge resistor is arranged in a filtering loop, so that energy is converted into heat to be released.

Description

Technical Field

[0001] The present invention relates to the technical field of doubly-fed converters, and particularly to a filtering circuit and a control method thereof in a doubly-fed converter. Background Art

[0002] A doubly-fed converter is a power device widely used in renewable energy fields such as wind power generation, mainly used for controlling and converting the electrical energy of a doubly-fed induction generator. It realizes independent control of the active power and reactive power of the generator by adjusting the voltage and frequency of the rotor side of the generator, thereby improving the efficiency and stability of the wind power generation system. The core components of a doubly-fed converter include a main power supply circuit, a filtering circuit, an analog board, etc. Among them, the filtering circuit is responsible for filtering the currents on the grid side and the generator side to reduce high-frequency noise and harmonic interference and improve the power quality. With the rapid development of renewable energy technologies, the performance requirements for doubly-fed converters are getting higher and higher, especially in terms of filtering effect, system stability, and device safety.

[0003] In the application of doubly-fed converters, there are some technical problems in the existing filtering circuits. First, the traditional filtering circuit is insufficient in suppressing high-frequency noise, especially in dealing with high-frequency common-mode noise such as IGBT switching noise, and the effect is not ideal. This will lead to an increase in electromagnetic interference and affect the stability and reliability of the system. Second, the discharge treatment of the filtering capacitor is not perfect, and there is a lack of a safe discharge mechanism. This not only increases the risk of electric shock but also may cause the energy in the filtering capacitor to be released reversely through sensitive components, thereby increasing the probability of device damage. Summary of the Invention

[0004] In view of the problems of poor processing effect of high-frequency common-mode noise and imperfect discharge treatment of the filtering capacitor in the existing filtering circuit of the doubly-fed converter, the present invention is proposed.

[0005] To solve the above technical problems, the present invention provides the following technical solutions: including a main power supply circuit, which includes an AC side and a generator. The generator is provided with a stator end and a rotor end, and the AC side is used to connect the generator to the grid; a filtering circuit, arranged at the stator end of the generator and connected to the AC side and the analog board, for rectifying and filtering; an analog board, connected to the filtering circuit, for controlling the entire system; wherein, a plurality of parallel current transformers A are arranged on the filtering circuit; and, each phase current of the filtering circuit is connected to a copper bar, the copper bar is connected to a filtering circuit, and a filtering capacitor is arranged on the filtering circuit; the filtering circuit is also provided with a filtering bypass, and a discharge resistor is arranged on the filtering bypass.

[0006] As a preferred solution of the filter circuit in the doubly-fed converter of the present invention, wherein: the AC side is a three-phase circuit, and each phase of the AC side circuit is connected with one of the filter circuits.

[0007] As a preferred solution of the filter circuit in the doubly-fed converter of the present invention, wherein: one end of each phase of the filter circuit is connected with an AC side cable, and each of the AC side cables is connected with a first copper bar group.

[0008] As a preferred solution of the filter circuit in the doubly-fed converter of the present invention, wherein: each of the first copper bar groups is connected with a group of filter circuits, there are several filter circuits in each group, a filter capacitor is provided on each of the filter circuits, and a filter bypass is connected in parallel with each group of the filter circuits.

[0009] As a preferred solution of the filter circuit in the doubly-fed converter of the present invention, wherein: the output ends of each group of the filter circuits are connected with a second copper bar group.

[0010] As a preferred solution of the filter circuit in the doubly-fed converter of the present invention, wherein: each of the first copper bar groups and the second copper bar groups is integrated into a rectifier bridge.

[0011] As a preferred solution of the filter circuit in the doubly-fed converter of the present invention, wherein: the AC side is a three-phase circuit, and each phase of the AC side circuit is provided with a current transformer A.

[0012] As a preferred solution of the filter circuit in the doubly-fed converter of the present invention, wherein: the output end of the current transformer A is divided into a positive pole and a negative pole, and the current output by each of the current transformers A is a filtered current.

[0013] As a preferred solution of the filter circuit in the doubly-fed converter of the present invention, wherein: a grid-connected contactor is further provided on the main power supply circuit, and the grid-connected contactor is provided with two parallel electromagnetic switches.

[0014] As a preferred solution of the filter circuit in the doubly-fed converter of the present invention, wherein: the main power supply circuit is further connected with a stator voltage detection branch and a stator current detection branch, and both the stator voltage detection branch and the stator current detection branch are connected with an analog board.

[0015] Advantages of the present invention: The present invention suppresses high-frequency common-mode noise (such as IGBT switching noise) and differential-mode harmonics through three-phase AC side cables, reducing electromagnetic interference; multiple groups of filter capacitors are provided to filter out harmonics, stabilize voltage, suppress interference, and reduce interference on the grid side and the generator side; at the same time, by setting a discharge resistor in the filter circuit, the energy is converted into heat and released. Since the resistance value of the discharge resistor is relatively large, it can slowly and continuously discharge high voltage, prevent the risk of electric shock, and also avoid the reverse release of the energy in the filter capacitor through sensitive components, reducing the probability of device damage, and can eliminate the residual voltage interference during restart, ensuring the accuracy of the converter control logic and feedback signal.

[0016] The present invention also provides a cooperative control method for the filter circuit of a doubly-fed converter, including the following steps:

[0017] S1. Data acquisition and preprocessing;

[0018] S2. High-frequency noise suppression;

[0019] S3. Discharge control.

[0020] As a preferred solution for the filter circuit in the doubly-fed converter of the present invention, wherein: in S1, the analog board collects stator current, stator voltage, and filter capacitor voltage.

[0021] As a preferred solution for the filter circuit in the doubly-fed converter of the present invention, wherein: in S1, the analog board collects the state of the discharge resistor and the grid-connected contactor.

[0022] As a preferred solution for the filter circuit in the doubly-fed converter of the present invention, wherein: in S2, according to the information collected in S1, it is judged whether it is necessary to activate the filter circuit for high-frequency suppression.

[0023] As a preferred solution for the filter circuit in the doubly-fed converter of the present invention, wherein: in S3, when performing high-frequency suppression according to S2, the real-time filter capacitor voltage is collected, and different discharge modes are selected.

[0024] As a preferred solution for the filter circuit in the doubly-fed converter of the present invention, wherein: in S3, when the filter circuit is operating, the temperature of the discharge resistor is monitored to judge whether to derate the operation.

[0025] Advantages of the present invention: The present invention accurately locates the high-frequency noise energy distribution in the 50 kHz - 100 kHz frequency band by collecting real-time data of stator current, voltage, and filter capacitor voltage, and combining Clarke transformation and fast Fourier transform analysis. According to the noise energy ratio, the IGBT switching frequency is dynamically adjusted, and the corresponding filter circuit is activated to effectively suppress high-frequency common-mode noise and differential-mode harmonics. Description of the Drawings

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0027] Figure 1 It is a simple circuit composition structure diagram of the filter circuit in the doubly-fed converter of the present invention.

[0028] Figure 2 It is a circuit diagram of the main power supply circuit of the filter circuit in the doubly-fed converter of the present invention.

[0029] Figure 3 It is a detailed circuit diagram of the stator side of the main power supply circuit of the filter circuit in the doubly-fed converter of the present invention.

[0030] Figure 4 It is a detailed circuit diagram of the filter circuit in the doubly-fed converter of the present invention.

[0031] Figure 5 It is a detailed circuit diagram of the analog board in the doubly-fed converter of the present invention. Specific Embodiments

[0032] To make the above objects, features, and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings of the specification.

[0033] In the following description, many specific details are set forth to facilitate a thorough understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0034] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that can be included in at least one implementation of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that exclude each other with other embodiments.

[0035] Furthermore, the present invention is described in detail with reference to the schematic diagrams. When describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional views showing the device structures will be enlarged locally out of the general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein. In addition, in actual production, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0036] Embodiment 1

[0037] Reference Figures 1 - 5 Figures 1 - 5 , for the first embodiment of the present invention, a filtering circuit in a doubly-fed converter is provided. This device includes a main power supply circuit 100, which includes an AC side 101 and a generator 105. The generator 105 is provided with a stator end and a rotor end. The AC side 101 is used to connect the generator 105 to the power grid; a filtering circuit 200, which is arranged at the stator end of the generator 105 and is connected to the AC side 101 and the analog board 400. The AC side 101 of the main power supply circuit 100 is filtered through the filtering circuit 200; an analog board 400, which is connected to the filtering circuit 200 and is used to control the entire system; wherein, a plurality of parallel current transformers A201 are arranged on the filtering circuit 200; and, each phase current of the filtering circuit 200 is connected to a first copper bar group 204a. The first copper bar group 204a is connected to a filtering circuit 205, and a filtering capacitor 206 is arranged on the filtering circuit 205; a filtering bypass 207 is further arranged on the filtering circuit 205, and a discharge resistor 208 is arranged on the filtering bypass 207.

[0038] Among them, the main power supply circuit 100 is used to connect the generator 105 to the power grid. The AC side 101 of the main power supply circuit 100 is an industrial three-phase power line. The main power supply circuit 100 is connected to a controller, and an analog board 400 is arranged in the controller. The analog board 400 is used to monitor, adjust and protect the operating state of the converter in real time. The analog board 400 collects various data on the main power supply circuit 100, such as the voltage of the filtering capacitor 206, the voltage of the grid side 301, the stator voltage 303, the stator current 302, etc., judges the various parameters of the system, so as to adjust the output of the converter. At the same time, the analog board 400 cooperates with the filtering circuit 200 to suppress high-frequency noise and maintain the stability of the AC side 101.

[0039] The analog board 400 adopts an FPGA+ARM dual-core architecture: the FPGA is responsible for μs-level current loop control, and the ARM realizes ms-level state monitoring.

[0040] The current transformer A201 of the filtering circuit 200 is used to detect the stator side current data, and the current transformer A201 is arranged in each item of the three-phase circuit. The first copper bar group 204a is used to connect the filtering circuit 200 to the main power supply circuit 100. The filtering circuit 200 includes slowly and continuously discharging high voltage through the discharge resistor 208 to prevent the risk of electric shock, converting electrical energy into heat energy. The power selection of the discharge resistor 208 satisfies: P≥(0.25×C×U2) / t, where C = 200 μF is the total filtering capacitor 206, U = 1140V is the system voltage, and t = 60s is the required discharge time.

[0041] During use, the main power supply circuit 100 connects the generator 105 to the power grid, and the electric energy generated by the generator 105 is transmitted to the filtering circuit 200 through the AC side 101. The current transformer A201 detects the stator side current data and transmits the detected current signal to the analog board 400. The copper busbar 204 connects the filtering circuit 200 to the main power supply circuit 100 to ensure stable current transmission. The filtering capacitor 206 in the filtering circuit 205 filters the current to remove high-frequency noise and harmonics and stabilize the voltage. The filtering bypass 207 provides a bypass channel for the current when needed, and the discharge resistor 208 is used to slowly and continuously release the high-voltage electric energy to prevent the risk of electric shock and release the electric energy as heat.

[0042] Embodiment 2

[0043] Referring to Figure 3 、 Figure 4 This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that: the AC side 101 is a three-phase circuit, and each phase of the circuit of the AC side 101 is connected to one filtering circuit 200 through an AC side cable 203.

[0044] One end of each phase of the filtering circuit 200 is connected to the AC side cable 203, and each AC side cable 203 is connected to a first copper busbar group 204a.

[0045] Each first copper busbar group 204a is connected to a group of filtering circuits 205. Each group of filtering circuits 205 has several pieces. Each filtering circuit 205 is provided with a filtering capacitor 206, and each group of filtering circuits 205 is connected in parallel with a filtering bypass 207.

[0046] The output ends of each group of filtering circuits 205 are all connected to a second copper busbar group 204b, and the first copper busbar groups 204a and the second copper busbar groups 204b are integrated into a rectifier bridge 204.

[0047] During use, the three-phase circuits of the AC side 101 are respectively connected to the filtering circuit 200, and each phase of the filtering circuit 200 is connected to the copper busbar 204 through the AC side 101 cable. The copper busbar 204 guides the current to the filtering circuit 205. The filtering capacitor 206 in the filtering circuit 205 filters the current to remove high-frequency noise and harmonics and stabilize the voltage. The filtering bypass 207 provides a bypass channel for the current when needed, and the output ends of each group of filtering circuits 205 are integrated into a rectifier bridge through the copper busbar 204 to achieve rectification and stable transmission of the current.

[0048] The remaining structures are the same as those in Embodiment 1.

[0049] Embodiment 3

[0050] Referring toFigure 3 , which is the third embodiment of the present invention. The difference between this embodiment and the second embodiment is that: the AC side 101 is a three-phase circuit, and each phase of the circuit of the AC side 101 is provided with a current transformer A201.

[0051] The output end of the current transformer A201 is divided into a positive pole and a negative pole, and the current output by each current transformer A201 is a filtered current 202.

[0052] During use, the current transformer A201 detects the current of each phase of the AC side 101, divides the detected current into a positive pole and a negative pole and outputs it, and transmits it as the filtered current 202 to the filter circuit 200. The filter circuit 200 performs filtering processing according to the filtered current 202 to ensure the stability and purity of the current.

[0053] The remaining structure is the same as that of Embodiment 2.

[0054] Embodiment 4

[0055] Referring to Figures 2 - 4 , a stator-side main circuit 300 is provided on the stator side of the main power supply circuit 100. The stator-side main circuit 300 is connected to the grid side 301. A stator voltage detection branch 103 and a stator current detection branch 104 are also connected to the stator-side main circuit 300. The stator voltage detection branch 103 and the stator current detection branch 104 are both connected to the analog board 400.

[0056] A fuse 305 is provided on the stator voltage detection branch 103. The fuse 305 is connected to a voltage dividing board 306 and is connected to the signal access terminal 401 of the analog board 400 through the voltage dividing board 306.

[0057] A current transformer B304 is provided on the stator current detection branch 104. The stator current 302 passes through the current transformer B304 and is connected to the signal access terminal 401 of the analog board 400. The analog board 400 is also provided with a hardware interface 402 for connecting to external devices. The filtered current 202, the stator current 302, and the stator voltage 303 are all provided with protection grounding terminals 403.

[0058] A grid-connected contactor 102 is also provided on the main power supply circuit 100. The grid-connected contactor 102 is provided with two parallel electromagnetic switches. During the grid connection / disconnection process, the safe transmission of electric energy is realized by closing or opening the main circuit. When grid-connected, one electromagnetic switch is closed first, and the inrush current is limited through a pre-charge circuit; the other electromagnetic switch is then closed to share the load current.

[0059] The main power supply circuit 100 is also connected to a stator voltage detection branch 103 and a stator current detection branch 104, and both the stator current 302 voltage measurement branch and the stator current detection branch 104 are connected to the analog board 400.

[0060] Among them, the main power supply circuit 100 adopts a double-break design. There is a main circuit breaker in front of the grid-connected contactor 102 in the main power supply circuit 100. The main circuit breaker and the grid-connected contactor 102 form a double-breaking protection, and the rated breaking capacity reaches 65 kA.

[0061] During use, the main circuit 300 on the stator side transmits the electric energy on the stator side to the grid side 301. The stator voltage detection branch 103 and the stator current detection branch 104 respectively detect the stator voltage 303 and the stator current 302, and transmit the detection signals to the analog board 400. The fuse 305 and the voltage dividing board 306 are used for protection and voltage division, and the current transformer B304 is used to detect the stator current 302. The analog board 400 is connected to external devices through the hardware interface 402 to realize the control and monitoring of the entire system. The two parallel contactors of the grid-connected contactor 102 ensure the reliable connection and disconnection of the main power supply circuit 100.

[0062] Embodiment 5

[0063] This embodiment also provides a cooperative control method for the filter circuit of a doubly-fed converter, including the following steps:

[0064] S1. Data acquisition and preprocessing;

[0065] S1.1. The analog board is connected to the current transformer B304 to collect the stator current, connected to the voltage dividing board 306, and the voltage signal attenuation process is carried out through the voltage dividing board to collect the stator voltage, connected to the filter circuit 200, and monitor the voltage of the filter capacitor 206;

[0066] S1.2. The FPGA of the analog board is synchronously triggered at a frequency of 20 kHz, sampled at the midpoint of each PWM cycle to eliminate switching noise; the ARM core collects the temperature of the discharge resistor 208 and the state of the grid-connected contactor 102 at 1 kHz;

[0067] S1.3. The analog board 400 performs Clarke transformation on the current signal;

[0068] S2. High-frequency noise suppression;

[0069] S2.1. Perform 1024-point FFT analysis on the transformed current signal, calculate the energy ratio in the frequency band of 50 kHz - 100 kHz, and judge whether high-frequency suppression is required;

[0070] S2.2. Adjust the IGBT switching frequency according to the noise energy;

[0071] S2.3. If it is determined that high-frequency suppression is required, activate the corresponding filter circuit 200, and at the same time, determine whether it is necessary to use the discharge resistor 208 in parallel with the capacitor for voltage equalization control;

[0072] S3. Discharge control;

[0073] S3.1. Select the discharge mode according to the voltage of the filter capacitor 206;

[0074] S3.2. Monitor the temperature T of the discharge resistor 208 and determine whether to operate at a derated condition;

[0075] Among them, according to the stator current i a 、i b 、i c collected in S1.1, and the stator voltage v a 、v b 、v c collected, use the following formula for the Clarke transformation in S1.3 to obtain i α 、i β ,i α 、i β which are the two-phase current components obtained after the three-phase transformation:

[0076] In S2.1, use the following formula to calculate the energy proportion in the 50 kHz - 100 kHz frequency band:

[0077]

[0078] When E hf > 3%, trigger high-frequency suppression, where E hf is the high-frequency noise energy proportion, X[k] is the complex array element after the fast Fourier transform, representing the amplitude of the current signal at the kth frequency component in the frequency domain, and k is the index number of the frequency component output by the FFT.

[0079] In S2.2, adjust the IGBT switching frequency according to the following formula, where f sw is the real-time switching frequency of the IGBT power device:

[0080]

[0081] In S2.3, if it is detected that the E hf of a certain phase > 5%, activate the filter circuit 200 corresponding to this phase. If the voltages of the filter capacitors 208 are unbalanced, start the parallel capacitor voltage equalization control.

[0082] Calculate the capacitor voltage unbalance degree ΔVcap according to the following formula:

[0083]

[0084] In S3.1:

[0085]

[0086] Select the corresponding mode according to the value of ΔVcap.

[0087] In S3.2, first calculate the PWM duty cycle D of the discharge resistor 208:

[0088]

[0089] If the temperature T of the discharge resistor 208 ≥ 120 °C, derate the operation and trigger an alarm signal to be sent to the analog board: D new = D·(1 - 0.8(T - 120) / 30)

[0090] Through the organic combination of dynamic frequency regulation, multi-branch collaborative filtering and intelligent discharge control, this method realizes the comprehensive improvement of high-frequency noise suppression, safe discharge and system stability without increasing the hardware complexity. All indicators are better than the industry standards and are applicable to the doubly-fed wind power generation scenarios with high voltage and high interference.

[0091] Importantly, it should be noted that the construction and arrangement of the present application shown in multiple different exemplary embodiments are only illustrative. Although only a few embodiments are described in detail in this disclosure, those who refer to this disclosure should easily understand that many modifications are possible (for example, the dimensions, scales, structures, shapes and proportions of various elements, and parameter values (such as temperature, pressure, etc.), installation arrangements, use of materials, color, orientation changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application. For example, an element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature, number or position of discrete elements can be changed or altered. Therefore, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. Therefore, the present invention is not limited to specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0092] In addition, in order to provide a concise description of the exemplary embodiments, not all features of the actual embodiments may be described (i.e., those features that are not relevant to the currently considered best mode of implementing the present invention or those that are not relevant to the implementation of the present invention).

[0093] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A filtering circuit in a doubly-fed converter, characterized in that: Including, The main power supply circuit (100) includes an AC side (101) for connecting a generator (105) to the power grid. The filter circuit (200) is provided at the stator end of the generator (105) and is connected to the AC side (101) and the analog board (400) for filtering. The analog board (400) is connected to the filter circuit (200) for controlling the entire system. Among them, a number of current transformers A (201) are provided in parallel on the filter circuit (200); and, Each phase current of the filter circuit (200) is connected to a copper bar (204), the copper bar (204) is connected to a filter circuit (205), and a filter capacitor (206) is provided on the filter circuit (205). The filter circuit (205) is further provided with a filter bypass (207), and a discharge resistor (208) is provided on the filter bypass (207).

2. The filter circuit in the doubly-fed converter according to claim 1, wherein: The AC side (101) is a three-phase circuit, and each phase of the AC side (101) circuit is connected to an AC side cable (203).

3. The filter circuit in the doubly-fed convertor according to claim 2, characterized in that: Each of the AC side cables (203) forms the main line of the filter circuit (200), and each AC side cable (203) is connected to a first copper bar group (204a).

4. The filter circuit in the doubly-fed converter according to any one of claims 1 to 3, characterized in that: Each copper bar (204) is connected to a group of filter circuits (205), each group of filter circuits (205) has several pieces, each filter circuit (205) is provided with a filter capacitor (206), and each group of filter circuits (205) is connected in parallel with a filter bypass (207).

5. The filter circuit in the doubly-fed converter according to claim 4, characterized in that: The output ends of each group of filter circuits (205) are all connected to a second copper bar group (204b).

6. The filter circuit in the doubly-fed converter according to claim 5, characterized in that: Each of the first copper bar groups (204a) and the second copper bar groups (204b) are integrated into a rectifier bridge (204).

7. The filter circuit in the doubly-fed converter according to any one of claims 1 to 3, 5, and 6, characterized in that: The AC side (101) is a three-phase circuit, and each phase of the AC side (101) circuit is provided with a current transformer A (201).

8. The filter circuit in the doubly-fed converter according to claim 7, characterized in that: The output end of the current transformer A (201) is divided into a positive pole and a negative pole, and the current output by each current transformer A (201) is a filtered current (202).

9. The filter circuit in the doubly-fed converter according to claim 1 to 3, 5, 6 or 8, characterized in that: A grid-connected contactor (102) is further provided on the main power supply circuit (100), and the grid-connected contactor (102) is provided with two electromagnetic switches connected in parallel.

10. The filter circuit in the doubly-fed converter according to claim 9, characterized in that: The main power supply circuit (100) is further connected to a stator voltage detection branch (103) and a stator current detection branch (104), and both the stator voltage detection branch (103) and the stator current detection branch (104) are connected to the analog board (400).

11. A cooperative control method for a filtering circuit of a doubly-fed converter, which is used for the filtering circuit in any one of claims 1-10, and is characterized in that: Including the following steps, S1. Data acquisition and preprocessing; S2. High-frequency noise suppression; S3. Discharge control.

12. The collaborative control method for the filter circuit of the doubly-fed converter according to claim 11, wherein: In S1, the analog board (400) acquires the stator current (302), the stator voltage (303), and the voltage of the filter capacitor (206).

13. The collaborative control method for the filter circuit of a doubly-fed converter according to claim 11 or 12, characterized in that: In S1, the analog board (400) acquires the states of the discharge resistor (208) and the grid-connected contactor (102).

14. The collaborative control method of the filter circuit of the doubly-fed converter according to claim 13, characterized in that: In S2, according to the information acquired in S1, it is judged whether it is necessary to activate the filter circuit (200) for high-frequency suppression.

15. The collaborative control method for the filter circuit of the doubly-fed converter according to claims 11, 12, and 14, characterized in that: In S3, when performing high-frequency suppression according to S2, the voltage of the filter capacitor (206) is collected in real time, and different discharge modes are selected.

16. The collaborative control method for the filter circuit of the doubly-fed converter according to claim 15, wherein: In S3, when the filter circuit (200) is operating, the temperature of the discharge resistor (208) is monitored to determine whether it is operating at a derated level.

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