A method, system, medium, and procedure for suppressing torsional vibration in the shaft system of a direct-drive fan.

Abstract

This invention discloses a method, system, medium, and program for suppressing shaft torsional vibration in direct-drive wind turbines, belonging to the technical field of wind turbine shaft torsional vibration suppression. The method includes the following steps: In the wind turbine grid-side controller, a maximum power point tracking (MPPT) strategy with optimal tip speed ratio is used to obtain the system's active power setpoint and speed setpoint; the actual speed of the permanent magnet synchronous generator (PMSG) and the actual DC bus voltage are obtained through built-in sensors; the deviation between the PMSG speed and DC bus voltage is introduced into the fuzzy control loop of the turbine-side controller; a reference value for the q-axis current increment is obtained through the built-in fuzzy control strategy; and the sum of the existing q-axis current and the q-axis current increment reference value is used as the reference value for the q-axis current to control the operating state of the PMSG. This invention incorporates both generator speed deviation and DC voltage deviation into the operating state control decision, thereby effectively suppressing shaft torsional vibration when the wind turbine participates in frequency regulation.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine shaft torsional vibration suppression technology, and relates to a method, system, medium and program for suppressing torsional vibration of direct-drive wind turbine shaft. Background Technology

[0002] As the proportion of wind power connected to the grid increases, the wind power grid connection standard clearly requires wind turbine units to have frequency support capabilities such as inertial support and primary frequency regulation. Grid-connected direct-drive permanent magnet synchronous wind turbine units (hereinafter referred to as "grid-connected direct-drive wind turbines") can simulate the inertia of synchronous generators through virtual synchronous generator (VSG) control, actively responding to grid frequency fluctuations, and have become the core unit type of future high-proportion renewable energy grids.

[0003] However, grid-connected direct-drive wind turbines face a critical issue of shaft torsional vibration when providing frequency support. Existing grid-connected direct-drive wind turbines' machine-side controllers rely solely on DC bus voltage deviation... ΔV dc The q-axis current reference value is generated by the PI controller. I sqref No consideration was given to speed deviation. Give s The impact of power grid frequency fluctuations on the speed of permanent magnet synchronous generators can lead to an imbalance between electromagnetic torque and transmission shaft torque, which can easily induce torsional vibration in the shaft system.

[0004] Existing suppression methods have various shortcomings. For example, patent CN107017647A (doubly fed wind turbine) uses "speed deviation + additional damping controller" to adjust the DC voltage reference value, which is only applicable to doubly fed turbines, and the damping parameters are fixed, making it difficult to adapt to the nonlinear operating conditions of direct-drive wind turbines. Patent CN120073856A (grid-type wind turbine) suppresses torsional vibration by adjusting the internal potential phase, but this requires changing the grid synchronization logic, which can easily affect the frequency support response speed. Traditional PI control or single-variable control has poor robustness. Under the superposition of sudden wind speed changes (such as gusts) and grid faults (such as short circuits), the torsional vibration suppression effect decreases significantly, and may even lead to fatigue damage of the drive train.

[0005] Therefore, there is an urgent need for a shaft torsional vibration suppression method adapted to direct-drive wind turbines with grid structure, which can effectively suppress torsional vibration while ensuring frequency support capability, and take into account both real-time control and robustness. Summary of the Invention

[0006] To address the shaft torsional vibration problem caused by "single DC voltage control" when grid-connected direct-drive wind turbines participate in grid frequency regulation, and the shortcomings of existing suppression methods such as poor adaptability and insufficient robustness, this invention proposes a method for suppressing shaft torsional vibration of direct-drive wind turbines. Through "dual-deviation fuzzy control + q-axis current increment synthesis", the method achieves synergistic optimization of torsional vibration suppression and frequency support. The specific technical solution is as follows.

[0007] A method for suppressing torsional vibration of a direct-drive fan shaft system includes the following steps:

[0008] S1: Obtain wind speed; In the grid-side controller of a grid-connected direct-drive wind turbine, obtain the active power setpoint of the wind turbine system based on the maximum power point tracking control strategy with the optimal tip speed ratio. P ref and the speed setpoint of the permanent magnet synchronous generator oh sref And determine the reference value of DC bus voltage. V dcref ;

[0009] S2: Obtain the actual rotational speed of the permanent magnet synchronous generator through a built-in sensor. oh s and the actual voltage of the DC bus V dc ;

[0010] S3: Based on the permanent magnet synchronous generator speed setpoint from step S1 oh sref DC bus voltage reference value V dcref The actual speed of the permanent magnet synchronous generator in step S2 oh s Actual DC bus voltage V dc Calculate the speed deviation respectively D oh s DC bus voltage deviation ΔV dc and will Give s and ΔV dc A fuzzy control module is introduced into the machine-side controller;

[0011] S4: In the fuzzy control module, the built-in fuzzy control strategy is used to... Give s and ΔV dc The process is performed to output the reference value for the q-axis current increment of the permanent magnet synchronous generator. I sqref ;

[0012] S5: The current q-axis actual current of the permanent magnet synchronous generator. I q The result obtained in step S4 I sqref Summing these values ​​yields the q-axis current reference value. I sqref,based on I sqref Control the operating status of the permanent magnet synchronous generator and suppress shaft torsional vibration.

[0013] Furthermore, the built-in sensor in step S2 includes: a sensor for collecting data. oh s Photoelectric speed sensor and for collecting V dc Hall voltage sensor.

[0014] Furthermore, the fuzzy control strategy in step S4 includes the following sub-steps:

[0015] S4-1: Determine the universe of discourse: ΔV dc The domain of discourse is [e vmin , e vmax ], Give s The domain of discourse is [e ωmin , e ωmax ], D I sqref The domain of discourse is [e qmin , e qmax Furthermore, all three universes of discourse are divided into five fuzzy subsets: negative large NB, negative small NS, zero ZO, positive small PS, and positive large PB; among them, e vmin e ωmin e qmin They are respectively ΔV dc , Give s , I sqref Lower bound of the domain of discourse; e vmax e ωmax e qmax They are respectively ΔV dc , Give s , I sqref The upper limit of the domain of discourse;

[0016] S4-2: Fuzzification Processing: Using Membership Functions to... Give s and ΔV dc The precise value is converted into the corresponding fuzzy variable;

[0017] S4-3: Fuzzy Inference: Based on a preset fuzzy rule table, inference is performed on fuzzy variables to obtain... I sqref fuzzy vector;

[0018] S4-4: Deblurring: [The text appears to be incomplete and requires further context.] I sqref The fuzzy vector is converted into a precise value and output to step S5.

[0019] Furthermore, in step S4-1: ΔV dc The domain of discourse is [-0.15, 0.15] pu. Give s The domain of discourse is [-0.09, 0.09] pu. I sqref The universe of discourse is [-0.1, 0.1] pu; pu is a per-unit value, and the reference values ​​are the rated DC bus voltage, the rated permanent magnet synchronous generator speed, and the rated q-axis current, respectively.

[0020] Furthermore, the membership function in step S4-2 is a triangular membership function, where: ΔV dc In the membership functions, NB corresponds to [-0.15, -0.10], NS corresponds to [-0.12, -0.03], ZO corresponds to [-0.05, 0.05], PS corresponds to [0.03, 0.12], and PB corresponds to [0.10, 0.15]. Give s In the membership functions, NB corresponds to [-0.09, -0.06], NS corresponds to [-0.07, -0.02], ZO corresponds to [-0.03, 0.03], PS corresponds to [0.02, 0.07], and PB corresponds to [0.06, 0.09]. The above interval divisions are based on the typical operating characteristics, fault condition boundaries, and control accuracy requirements of grid-type direct-drive wind turbines, and were determined after simulation verification and optimization through engineering practice.

[0021] Furthermore, the preset fuzzy rule table in step S4-3 is shown in Table 1, where rows represent Give s Fuzzy subsets, columns represent ΔV dc A fuzzy subset, with cells as I sqref Fuzzy subsets:

[0022] Table 1 Preset Fuzzy Rule Table

[0023] .

[0024] Furthermore, the defuzzification in step S4-4 employs a weighted average method, calculated using the following formula:

[0025] I sqref = ∑( m i × x i ) / ∑ m i ,in m i for I sqref The membership degree of each fuzzy subset x i is the center value of each fuzzy subset.

[0026] A system for suppressing torsional vibration of a direct-drive fan shaft includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the steps in the above-described method.

[0027] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above method.

[0028] A computer program product, comprising a computer program, characterized in that the computer program, when executed by a processor, implements the steps in the above-described method.

[0029] This invention offers the following advantages over existing technologies: Significant torsional vibration suppression: Compared to traditional single DC voltage control, the dual-deviation fuzzy control of this invention can reduce shaft torsional vibration amplitude by more than 30% and extend the fatigue life of the transmission chain by 2-3 times. Strong frequency support capability: Through the synergy of VSG control and fuzzy control, the wind turbine frequency adjustment response time is ≤100ms, meeting the requirements of GB / T 19963.1-2021 "Technical Regulations for Wind Farm Access to Power Systems". Strong robustness: Under conditions such as sudden wind speed changes (e.g., gusts from 6m / s to 10m / s) and three-phase short-circuit faults in the power grid (fault clearing time 100ms), the torsional vibration suppression success rate is ≥95%, far exceeding the 70% of traditional PI control. High engineering adaptability: The domain range, membership function, and fuzzy rules are adaptable to most commercial grid-connected direct-drive wind turbines, requiring no major hardware modifications and only software upgrades for implementation. Attached Figure Description

[0030] Figure 1 This is a block diagram of a method for suppressing torsional vibration of a direct-drive fan shaft system provided by the present invention.

[0031] Figure 2 It is a visualization of a fuzzy rule table.

[0032] Figure 3 It is the membership function of DC voltage.

[0033] Figure 4 It is the membership function of the rotational speed of the permanent magnet synchronous generator.

[0034] Figure 5 It is the membership function of the q-axis current increment reference value. Detailed Implementation

[0035] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance, quantity, or position.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] The core idea of ​​this invention is to reduce the speed deviation of the permanent magnet synchronous generator. Give s Deviation from DC bus voltage D V dc As a dual input, the q-axis current increment is intelligently generated through fuzzy control. I sqref The actual q-axis current of the permanent magnet synchronous generator I q Synthesize new reference values I sqref The electromagnetic torque of the permanent magnet synchronous generator is dynamically adjusted to balance the transmission shaft torque and suppress torsional vibration. The overall control block diagram is as follows: Figure 1As shown in the figure, MSC For machine-side converters, GSC It is a grid-side converter. V g This is the grid voltage. V WT This is the terminal voltage. Z This is the equivalent impedance of the box-type transformer. Z = R + jX ,in, R For resistance, X For resistance, j The unit is imaginary. The sensor collects the port voltage and current of the wind turbine, which are respectively... V WTabc and I WTabc The Power module calculates the active power output of the current wind turbine. P WT and reactive power Q WT , Q ref This is the reference value for output reactive power. H and D are the virtual inertia coefficient and damping, respectively. E 0 represents the per-unit value of the rated voltage at the machine terminals. E ref This is the voltage reference value for the outer loop of the grid-side voltage. i This represents the phase angle of the port voltage. I gdref and I gqref These are the d-axis and q-axis current reference values ​​for the inner loop of the grid-side current, respectively. I sdref This is the reference value for the d-axis current of the inner loop of the machine-side current. I sabc The generator current on the generator side is obtained through a current sensor. Through coordinate transformation, the actual d-axis and q-axis currents of the generator are obtained. I sd and I sq . i s This is the generator rotor position angle. oh h This refers to the rotational speed of the impeller shaft. The specific steps are as follows:

[0039] S1 reference value acquisition. The grid-side controller uses the optimal tip speed ratio. l opt MPPT strategy, l opt Typically, a value of 7-9 is used. Real-time wind speed is collected via a wind speed sensor. vwind (Unit: m / s), based on the wind turbine radius R (Unit: m), Calculate the speed setpoint of the permanent magnet synchronous generator. oh sref = l opt × v wind / R (unit: rad / s). Based on the power characteristic curve of a permanent magnet synchronous generator, P=k× oh s 3 (k is the power coefficient, determined by the fan model), combined with oh sref Calculate the active power setpoint P ref (Unit: kW). DC bus voltage reference value V dcref The value is set according to the rated parameters of the wind turbine (e.g., 1140V is usually used for 1.5MW models).

[0040] S2 actual value acquisition. An optoelectronic speed sensor (mounted at the rotor shaft end of the permanent magnet synchronous generator, sampling frequency 1kHz) is used to acquire the actual speed. oh s The actual voltage is acquired using a Hall voltage sensor (installed on the DC bus side, with a measurement accuracy of ±0.5%). V dc The sensor signal is filtered (first-order low-pass filter, cutoff frequency 50Hz) before being input to the machine-side controller to avoid high-frequency noise interference.

[0041] S3 deviation calculation. Calculate the two deviations separately: speed deviation. Give s = oh sref - oh s (like Give s A positive value indicates the actual rotational speed is lower than the optimal value; a negative value indicates it is higher than the optimal value. (DC voltage deviation) ΔV dc = V dcref - V dc (like ΔV dc A positive value indicates the actual voltage is lower than the reference value; a negative value indicates it is higher than the reference value. The deviation signal is then amplitude-limited (to ensure...). Give s ∈[-0.09,0.09]pu、 ΔV dc ∈[-0.15,0.15] pu), to prevent exceeding the fuzzy control domain.

[0042] S4 Fuzzy Control. The fuzzy control module is the core of this invention, and the specific process is as follows:

[0043] S4-1 Universe of discourse defined. Based on typical parameters of 1-3MW grid-connected direct-drive wind turbines, the universe of discourse is defined as follows: ΔV dc ∈[-0.15,0.15] pu (reference value = rated DC voltage). Give s ∈[-0.09,0.09] pu (reference value = rated permanent magnet synchronous generator speed). I sqref ∈[-0.1,0.1] pu (reference value = rated q-axis current); each universe of discourse is divided into five fuzzy subsets: NB (negative large), NS (negative small), ZO (zero), PS (positive small), and PB (positive large), covering the common deviation range of wind turbines.

[0044] S4-2 fuzzification processing. A triangular membership function is used to fuzzify... ΔV dc、 Give s and I sqref The precise value is converted into a fuzzy variable, such as Figure 3-Figure 5 As shown. For example:

[0045] when ΔV dc When V = 0.06, its membership degree to the PS subset is 0.8, and its membership degree to the ZO subset is 0.2. The "fuzzy feature" of the deviation is quantified through membership measurement. Triangular function calculation is simple (only the interval endpoints and the current value are needed to calculate the membership degree), ensuring real-time control (fuzzification time ≤ 1ms).

[0046] S4-3 Fuzzy Reasoning. Reasoning is performed based on a preset fuzzy rule table, as shown in Table 1. Figure 2 It is a visualization of a fuzzy rule table.

[0047] Table 1 Preset Fuzzy Rule Table

[0048]

[0049] For example: if Give s =NB (actual speed is much lower than the reference value), ΔV dc =NB (actual voltage is much lower than the reference value), then the inference output is... I sqref=PB. The rule table achieves decision-making similar to human intuition through the mapping of "deviation combination - control action", without the need to build complex mathematical models, and is suitable for nonlinear working conditions.

[0050] S4-4 Defuzzification. A weighted average method is used to convert the fuzzy vector of ΔIsqref into an accurate value.

[0051] For example: if the reasoning leads to I sqref The membership degree of NS is 0.6, the membership degree of ZO is 0.4, the center value of NS is -0.03, and the center value of ZO is 0. I sqref =(0.6×(-0.03)+0.4×0) / (0.6+0.4)=-0.018pu, the precise value can be directly input into the generator-side converter control. The weighted average method avoids the "either / or" defect of the maximum membership method, and the output value transitions smoothly, preventing secondary torsional vibration caused by sudden torque changes in the permanent magnet synchronous generator.

[0052] S5 Current Synthesis and Control. Acquire the current actual q-axis current of the permanent magnet synchronous generator. I q (Obtained from the machine-side converter current sensor). Synthetic q-axis current reference value. I sqref = I q + I sqref For example: if I q =0.5pu、 I sqref =-0.018pu, then I sqref =0.482 pu. The machine-side converter tracks via space vector pulse width modulation (SVPWM). I sqref Adjust the electromagnetic torque of the permanent magnet synchronous generator: If I sqref The electromagnetic torque decreases, and the speed of the wind turbine-driven permanent magnet synchronous generator increases (correction). Give s (negative deviation), while the DC bus voltage gradually recovers due to power balance (correction). ΔV dc (Negative deviation) ultimately achieves shaft torque balance and suppresses torsional vibration.

[0053] The following uses a 1.5MW grid-connected direct-drive wind turbine (with an embedded permanent magnet synchronous generator, rated speed of 1500r / min, and rated DC bus voltage of 1140V) as an example to illustrate the implementation process of the present invention in detail.

[0054] I. Parameter Settings

[0055] 1. Reference parameter: Optimal tip speed ratio l opt =8, wind turbine radius R =40m, therefore oh sref =8× v wind / 40=0.2× v wind (rad / s); P ref =0.5× r ×π× R 2 × v wind 3 × C p( r For air density, take 1.225 kg / m³. 3 ; C p is the wind energy utilization coefficient, taken as 0.45). V dcref =1140V (per unit value 1p.u.).

[0056] 2. Fuzzy control parameters:

[0057] 1. Domain of discourse: ΔV dc ∈[-0.15,0.15] pu (corresponding to the actual voltage range of 969V~1311V). Give s ∈[-0.09,0.09] pu (corresponding to the actual speed range of 1365r / min~1635r / min). I sqref ∈[-0.1,0.1] pu (corresponding to the actual current range of -180A~180A, rated q-axis current 1800A).

[0058] 2. Membership function: Trigonometric function, interval division as described above.

[0059] 3. Fuzzy rule table: Use the rules in the aforementioned table.

[0060] 4. Defuzzification: Weighted average method, with center values ​​NB=-0.08, NS=-0.03, ZO=0, PS=0.03, PB=0.08.

[0061] II. Operating Condition Simulation and Results

[0062] 1. Simulation conditions: The power grid frequency suddenly drops from 50Hz to 49.5Hz (requiring the wind turbine to provide primary frequency regulation support), while the wind speed suddenly increases from 8m / s to 10m / s (gust disturbance).

[0063] 2. Results of virtual synchronous machine control (single DC voltage PI control): Shaft torsional vibration amplitude: ±0.05pu (corresponding to torque fluctuation ±75kN·m); frequency recovery time: 1.2s; DC bus voltage fluctuation: ±8%.

[0064] 3. Results of the method of the present invention: Shaft torsional vibration amplitude: ±0.035pu (corresponding to torque fluctuation of ±52.5kN·m), amplitude reduced by 30%; frequency recovery time: 0.96s, shortened by 20%; DC bus voltage fluctuation: ±5%, stability improved by 37.5%.

[0065] III. Implementation Steps Verification

[0066] Step S1: Wind speed v wind When = 8m / s, oh sref =0.2×8=1.6rad / s (1528r / min, per unit value 1p.u.), P ref =0.5×1.225×π×40²×8³×0.45≈1.2MW; Vdcref=1140V (1p.u.);

[0067] Step S2: After the frequency drop, the actual speed of the permanent magnet synchronous generator oh s =1.52rad / s (1456r / min, per unit value 0.94pu), actual DC voltage V dc =1083V (0.95pu);

[0068] Step S3: Give s =1-0.94=0.06pu (PS subset), ΔVdc=1-0.95=0.05pu (PS subset);

[0069] Step S4: After blurring Give s Membership degree of PS is 1.0. ΔV dc The membership degree of PS is 1.0; look up the rule table. I sqref =NS(membership degree 1.0); Defuzzification yields... Isqref =-0.03pu (actual current -54A);

[0070] Step S5: Current I q =0.6 pu (1080A), I sqref =0.6+(-0.03)=0.57pu (1026A); SVPWM control reduces the electromagnetic torque of the permanent magnet synchronous generator, increasing the wind turbine drive speed. Give s As the vibration gradually decreases to 0, torsional vibration is suppressed.

[0071] Although embodiments of the present invention have been shown and described above, it is understood that these embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and alterations to the above embodiments within the scope of the present invention without departing from its principles and spirit. The scope of protection of the present invention is defined by the claims and their equivalents.

Claims

1. A method for suppressing torsional vibration of a direct-drive fan shaft system, characterized in that, Includes the following steps: S1: Obtain wind speed; In the grid-side controller of a grid-connected direct-drive wind turbine, obtain the active power setpoint of the wind turbine system based on the maximum power point tracking control strategy with the optimal tip speed ratio. P ref and the speed setpoint of the permanent magnet synchronous generator ω sref And determine the reference value of DC bus voltage. V dcref ; S2: Obtain the actual rotational speed of the permanent magnet synchronous generator through a built-in sensor. ω s and the actual voltage of the DC bus V dc ; S3: Based on the permanent magnet synchronous generator speed setpoint from step S1 ω sref DC bus voltage reference value V dcref The actual speed of the permanent magnet synchronous generator in step S2 ω s Actual DC bus voltage V dc Calculate the speed deviation respectively Δω s DC bus voltage deviation ΔV dc and will Δω s and ΔV dc A fuzzy control module is introduced into the machine-side controller; S4: In the fuzzy control module, the built-in fuzzy control strategy is used to... Δω s and ΔV dc The process is performed to output the reference value for the q-axis current increment of the permanent magnet synchronous generator. ΔI sqref ; S5: The current q-axis actual current of the permanent magnet synchronous generator. I q The result obtained in step S4 ΔI sqref Summing these values ​​yields the reference value for the q-axis current. I sqref ,based on I sqref Control the operating status of the permanent magnet synchronous generator and suppress shaft torsional vibration.

2. The method according to claim 1, characterized in that, The built-in sensors in step S2 include: sensors for collecting data. ω s Photoelectric speed sensor and used for data acquisition V dc Hall voltage sensor.

3. The method according to claim 1, characterized in that, The fuzzy control strategy in step S4 includes the following sub-steps: S4-1: Determine the universe of discourse: ΔV dc The domain of discourse is [e vmin , e vmax ], Δω s The domain of discourse is [e ωmin , e ωmax ], ΔI sqref The domain of discourse is [e qmin , e qmax Furthermore, all three universes of discourse are divided into five fuzzy subsets: negative large NB, negative small NS, zero ZO, positive small PS, and positive large PB; among them, e vmin e ωmin e qmin They are respectively ΔV dc , Δω s , ΔI sqref Lower bound of the domain of discourse; e vmax e ωmax e qmax They are respectively ΔV dc , Δω s , ΔI sqref The upper limit of the domain of discourse; S4-2: Fuzzification Processing: Using Membership Functions to... Δω s and ΔV dc The precise value is converted into the corresponding fuzzy variable; S4-3: Fuzzy Inference: Based on a preset fuzzy rule table, inference is performed on fuzzy variables to obtain... ΔI sqref fuzzy vector; S4-4: Deblurring: [The text appears to be incomplete and requires further context.] ΔI sqref The fuzzy vector is converted into a precise value and output to step S5.

4. The method according to claim 3, characterized in that, In step S4-1: ΔV dc The domain of discourse is [-0.15, 0.15] pu. Δω s The domain of discourse is [-0.09, 0.09] pu. ΔI sqref The domain of discourse is [-0.1, 0.1] pu; pu is a per-unit value, and the reference values ​​are the rated DC bus voltage, the rated permanent magnet synchronous generator speed, and the rated q-axis current, respectively.

5. The method according to claim 3, characterized in that, The membership function in step S4-2 is a triangular membership function, where: ΔV dc In the membership functions, NB corresponds to [-0.15, -0.10], NS corresponds to [-0.12, -0.03], ZO corresponds to [-0.05, 0.05], PS corresponds to [0.03, 0.12], and PB corresponds to [0.10, 0.15]. Δω s In the membership functions, NB corresponds to [-0.09, -0.06], NS corresponds to [-0.07, -0.02], ZO corresponds to [-0.03, 0.03], PS corresponds to [0.02, 0.07], and PB corresponds to [0.06, 0.09].

6. The method according to claim 3, characterized in that, The preset fuzzy rule table in step S4-3 is shown in the table below, where rows represent ΔV dc Fuzzy subsets, columns represent Δω s A fuzzy subset, with cells as ΔI sqref Fuzzy subsets: 。 7. The method according to claim 3, characterized in that, The defuzzing in step S4-4 uses a weighted average method, and the calculation formula is as follows: ΔI sqref = ∑( μ i × x i ) / ∑ μ i ,in μ i for ΔI sqref The membership degree of each fuzzy subset x i is the center value of each fuzzy subset.

8. A system for suppressing torsional vibration of a direct-drive fan shaft, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-7.

Images