Wind turbine torque feedforward control method and system based on generator rotational speed

Abstract

The application discloses a wind turbine torque feedforward control method and system based on generator speed, wherein in the grid-connected power generation mode, a generator speed measurement value is sent to a main PLC, a difference between a filtered value after filtering of the generator speed measurement value and a generator speed given value is taken as an input of a PI controller, and an output of the PI controller is taken as a first component of a generator electromagnetic torque given value; the difference between the filtered value after filtering of the generator speed measurement value and the generator speed given value is subjected to a phase-advance filter and a notch filter, when the unit operates in a variable speed interval below the rated wind speed, a generator speed signal is multiplied by a proportional gain and then subjected to amplitude limiting processing to be taken as a second component of the generator electromagnetic torque given value; and the first component and the second component are superposed to obtain the electromagnetic torque given value of the unit operating in the variable speed interval below the rated wind speed. The application can reduce the peak-to-peak value of the fluctuation of the frequency component below 0.1 Hz in the hub center thrust, the tower front and back direction bending moment load and the blade flap direction bending moment load.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind turbine torque feedforward control, and particularly to a wind turbine torque feedforward control method based on generator speed, a wind turbine torque feedforward control system, a storage medium and a computing device. BACKGROUND

[0002] When the wind turbine operates in the grid-connected power generation mode, the 0.1Hz or lower frequency component of the wind turbine operating thrust, the tower front-back direction bending moment load and the blade flapwise direction bending moment load can be adjusted by changing the generator speed signal or the blade angle signal.

[0003] When the wind turbine operates in the variable speed range below the rated wind speed, in order to obtain maximum wind energy capture, the blade angle is usually maintained at the angle value corresponding to the optimal gain of the generator electromagnetic torque VS generator speed, and the given value of the generator electromagnetic torque is proportional to the optimal gain and the square of the generator speed. On the one hand, the fluctuation amplitude of the 0.1Hz or lower frequency component of the wind turbine operating thrust, the tower front-back direction bending moment load and the blade flapwise direction bending moment load is large; on the other hand, the variable speed operation time accounts for a high proportion in the annual wind frequency distribution hours; resulting in that the tower front-back direction bending moment fatigue load of the wind turbine in the 20-year design life is relatively large, and the blade flapwise direction bending moment fatigue load is also increased. Therefore, it is difficult to balance wind energy capture and wind turbine component load. SUMMARY

[0004] The first object of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a wind turbine torque feedforward control method based on generator speed, which can reduce the peak-to-peak value of the 0.1Hz or lower frequency component of the hub center thrust, the tower front-back direction bending moment load and the blade flapwise direction bending moment load by adjusting the given value of the generator electromagnetic torque in the variable speed range without increasing any cost and almost without power loss.

[0005] The second object of the present application is to provide a wind turbine torque feedforward control system based on generator speed.

[0006] The third object of the present application is to provide a storage medium.

[0007] The fourth object of the present application is to provide a computing device.

[0008] The first object of the present application is achieved by the following technical scheme: a wind turbine torque feedforward control method based on generator speed, which performs the following operations:

[0009] When the wind turbine operates in the grid-connected power generation mode, the generator speed signal calculated by the frequency converter, i.e. the generator speed measurement value, is sent to the main PLC of the wind turbine in real time;

[0010] The main PLC subtracts the filtered value of the generator speed measurement value processed by the low-pass filter and the notch filter 1 from the generator speed given value, and the difference is taken as the input of the PI controller, and the output of the PI controller is taken as the first component of the generator electromagnetic torque given value;

[0011] The main PLC subtracts the filtered value of the generator speed measurement value processed by the low-pass filter and the notch filter 1 from the generator speed given value, and the difference is taken as the input of the PI controller, and the output of the PI controller is taken as the first component of the generator electromagnetic torque given value;

[0012] The main PLC superimposes the first component and the second component of the generator electromagnetic torque given value to obtain the electromagnetic torque given value of the wind turbine operating in the variable speed range below the rated wind speed, and then sends it to the frequency converter of the wind turbine for execution, so as to realize the desired electromagnetic torque value.

[0013] Further, the transfer function of the low-pass filter is as follows:

[0014] Or

[0015] In the formula, s is a complex variable, T1 is the time constant of the first-order low-pass filter, ξ3 is the damping ratio of the second-order low-pass filter, and ω3 is the cutoff frequency of the second-order low-pass filter.

[0016] Further, the transfer function of the notch filter 1 is as follows:

[0017]

[0018] In the formula, s is a complex variable, ξ1 and ξ2 are the damping ratios of the notch filter, and ω1 and ω2 are the frequencies of the notch filter.

[0019] Further, the transfer function of the phase-lead filter is as follows:

[0020]

[0021] In the formula, s is a complex variable, a is the graduation coefficient of the phase-lead filter, and T3 is the time constant of the phase-lead filter.

[0022] Further, the transfer function of the notch filter 2 is as follows:

[0023]

[0024] In the formula, s is a complex variable, and ξ4 and ξ5 are notch filter damping ratios, and ω4 and ω5 are notch filter frequencies.

[0025] Further, the generator speed measurement value is transmitted in real time to the main PLC of the wind turbine through the CANopen communication mode.

[0026] The second object of the present application is achieved by the following technical solution: a wind turbine torque feedforward control system based on generator speed, which is used to implement the wind turbine torque feedforward control method based on generator speed, and comprises:

[0027] The transmission module is used to transmit the generator speed signal calculated by the frequency converter, i.e., the generator speed measurement value, to the main PLC of the wind turbine in real time when the wind turbine operates in the grid-connected power generation mode.

[0028] The first component acquisition module is used to subtract the filtered value of the generator speed measurement value after being processed by the low-pass filter and the notch filter 1 from the generator speed given value, and the difference value is used as the input of the PI controller, and the output of the PI controller is used as the first component of the generator electromagnetic torque given value.

[0029] The second component acquisition module is used to subtract the filtered value of the generator speed measurement value after being processed by the low-pass filter and the notch filter 1 from the generator speed given value, and then the difference value is processed by the phase-lead filter and the notch filter 2, and when the wind turbine operates in the variable speed interval below the rated wind speed, the generator speed signal after being processed by the phase-lead filter and the notch filter 2 is multiplied by the proportional gain, and then the amplitude limiting processing is performed to obtain the electromagnetic torque compensation value of the generator speed torque feedforward control, which is used as the second component of the generator electromagnetic torque given value.

[0030] The electromagnetic torque given value acquisition module is used to superimpose the first component and the second component of the generator electromagnetic torque given value to obtain the electromagnetic torque given value of the wind turbine operating in the variable speed interval below the rated wind speed, and then the wind turbine frequency converter is executed to achieve the desired electromagnetic torque value.

[0031] The third object of the present application is achieved by the following technical solution: a storage medium storing a program, wherein the program is executed by a processor to implement the wind turbine torque feedforward control method based on generator speed.

[0032] The fourth object of the present application is achieved by the following technical solution: a computing device comprising a processor and a memory for storing a program executable by the processor, wherein the processor executes the program stored in the memory to implement the wind turbine torque feedforward control method based on generator speed.

[0033] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0034] In the premise of not increasing any cost and almost no power generation loss, the fatigue load of the tower and the cost of the wind turbine are reduced by attenuating the frequency components below 0.1 Hz in the tower fore-aft direction bending moment signal of the wind turbine operating in the variable speed range below the rated wind speed.

[0035] In the premise of not increasing any cost and almost no power generation loss, the fatigue load of the tower and the cost of the wind turbine are reduced by attenuating the frequency components below 0.1 Hz in the tower fore-aft direction bending moment signal of the wind turbine operating in the variable speed range below the rated wind speed.

[0036] T=T(ω,Ω,θ)

[0037]

[0038]

[0039] As can be seen from the above formula, the thrust T borne by the wind turbine is related to the wind speed ω, the generator speed Ω and the blade angle θ, and any change in the wind speed, the generator speed or the blade angle will cause a corresponding change in the thrust. The present application attenuates the peak-to-peak value of the hub center thrust fluctuation by generating an additional generator speed change dΩ'.

[0040] In summary, the present application proposes a wind turbine torque feedforward control method and system based on the generator speed, which takes the generator speed signal as input and does not increase any cost and almost no power generation loss, by adjusting the generator electromagnetic torque given value in the variable speed range, thereby changing the generator speed, to achieve the purpose of reducing the peak-to-peak value of the hub center thrust fluctuation. In view of the fact that the variable speed operating range corresponds to a large number of annual wind frequency distribution hours in the wind farm where large-capacity, long-diameter wind turbine generators are currently operating, the present application is applied in the variable speed range below the rated wind speed, which can greatly attenuate the frequency components below 0.1 Hz in the tower fore-aft direction bending moment signal and the blade flapwise direction bending moment signal of the wind turbine, thereby greatly reducing the tower fore-aft direction fatigue load and the blade flapwise direction fatigue load, which has practical application value and is worth promoting. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is a schematic diagram of the method of the present application.

[0042] Figure 2 It is a comparison diagram of the generator electromagnetic torque VS generator speed frequency domain Bode diagram when the generator speed torque feedforward control function is turned on and off.

[0043] Figure 3 It is a comparison diagram of the generator electromagnetic torque VS cabin fore-aft direction speed frequency domain Bode diagram when the generator speed torque feedforward control function is turned on and off.

[0044] Figure 4 Fig. 6 is a comparison diagram of generator electromagnetic torque vs. tower bottom My bending moment frequency domain Bode diagram when the generator speed torque feedforward control function is turned on and off.

[0045] Figure 5 Fig. 7 is a comparison diagram of generator electromagnetic torque vs. blade root flap My bending moment frequency domain Bode diagram when the generator speed torque feedforward control function is turned on and off.

[0046] Figure 6 Fig. 8 is a comparison diagram of wind speed vs. generator speed step response when the generator speed torque feedforward control function is turned on and off.

[0047] Figure 7 Fig. 9 is a comparison diagram of generator speed time sequence when the generator speed torque feedforward control function is turned on and off.

[0048] Figure 8 Fig. 10 is a comparison diagram of wind turbine (referred to as wind machine) output power time sequence when the generator speed torque feedforward control function is turned on and off.

[0049] Figure 9 Fig. 11 is a comparison diagram of hub center thrust time sequence when the generator speed torque feedforward control function is turned on and off.

[0050] Figure 10 Fig. 12 is a comparison diagram of tower bottom My bending moment time sequence when the generator speed torque feedforward control function is turned on and off.

[0051] Figure 11 Fig. 13 is a comparison diagram of blade root flap My bending moment time sequence when the generator speed torque feedforward control function is turned on and off.

[0052] Figure 12 Fig. 14 is a comparison diagram of tower bottom My bending moment spectrum density when the generator speed torque feedforward control function is turned on and off.

[0053] Figure 13 Fig. 15 is a comparison diagram of blade root flap My bending moment spectrum density when the generator speed torque feedforward control function is turned on and off.

[0054] Figure 14 Fig. 16 is a schematic diagram of the system architecture of the present application. DETAILED DESCRIPTION

[0055] The present application will be further described by way of example with reference to the accompanying drawings.

[0056] Example 1

[0057] As Figure 1As shown, the embodiment discloses a wind turbine torque feedforward control method based on generator speed, and the following operations are performed:

[0058] When the wind turbine operates in the grid-connected power generation mode, the generator speed signal (i.e., the generator speed measurement value) calculated by the frequency converter is sent to the main PLC of the wind turbine in real time through a communication mode such as CANopen;

[0059] The main PLC subtracts the filtered value of the generator speed measurement value processed by the low-pass filter and the notch filter 1 from the generator speed given value, and the difference is used as the input of the PI controller. The output of the PI controller is used as the first component of the generator electromagnetic torque given value.

[0060] The main PLC processes the difference between the filtered value of the generator speed measurement value processed by the low-pass filter and the notch filter 1 and the generator speed given value through the phase-lead filter and the notch filter 2. When the wind turbine operates in the variable speed range below the rated wind speed, the generator speed signal processed by the phase-lead filter and the notch filter 2 is multiplied by the proportional gain Kp, and then subjected to amplitude limiting to obtain the electromagnetic torque compensation value of the generator speed torque feedforward control, which is used as the second component of the generator electromagnetic torque given value.

[0061] The main PLC superimposes the first component and the second component of the generator electromagnetic torque given value to obtain the electromagnetic torque given value of the wind turbine operating in the variable speed range below the rated wind speed, and then sends it to the frequency converter of the wind turbine for execution to achieve the desired electromagnetic torque value.

[0062] Specifically, the transfer function of the low-pass filter is as follows:

[0063] Or

[0064] In the formula, s is a complex variable, T1 is the time constant of the first-order low-pass filter, ξ3 is the damping ratio of the second-order low-pass filter, and ω3 is the cutoff frequency of the second-order low-pass filter.

[0065] Specifically, the transfer function of the notch filter 1 is as follows:

[0066]

[0067] In the formula, s is a complex variable, ξ1 and ξ2 are the damping ratios of the notch filter, and ω1 and ω2 are the frequencies of the notch filter.

[0068] Specifically, the transfer function of the phase-lead filter is as follows:

[0069]

[0070] where s is a complex variable, a is a phase lead filter graduation coefficient, and T3 is a phase lead filter time constant.

[0071] Specifically, the transfer function of the notch filter 2 is as follows:

[0072]

[0073] where s is a complex variable, ξ4 and ξ5 are notch filter damping ratios, and ω4 and ω5 are notch filter frequencies.

[0074] Figure 2 For the generator speed torque feedforward control function being turned on and off, the generator electromagnetic torque VS generator speed frequency domain Bode diagram comparison. As can be seen from the figure, when the generator speed torque feedforward control is turned on, the low frequency component below 0.1 Hz in the generator speed signal is obviously attenuated.

[0075] Figure 3 For the generator speed torque feedforward control function being turned on and off, the generator electromagnetic torque VS cabin fore-aft direction speed frequency domain Bode diagram comparison. As can be seen from the figure, when the generator speed torque feedforward control is turned on, the low frequency component below 0.1 Hz in the cabin fore-aft direction speed signal is obviously attenuated.

[0076] Figure 4 For the generator speed torque feedforward control function being turned on and off, the generator electromagnetic torque VS tower bottom fore-aft direction My moment frequency domain Bode diagram comparison. As can be seen from the figure, when the generator speed torque feedforward control is turned on, the low frequency component below 0.1 Hz in the tower bottom fore-aft direction My moment signal is obviously attenuated.

[0077] Figure 5 For the generator speed torque feedforward control function being turned on and off, the generator electromagnetic torque VS blade root flapwise direction My moment frequency domain Bode diagram comparison. As can be seen from the figure, when the generator speed torque feedforward control is turned on, the low frequency component below 0.1 Hz in the blade root flapwise direction My moment signal is obviously attenuated.

[0078] Figure 6 For the generator speed feedforward control function being turned on and off, the wind speed VS generator speed unit step response time sequence comparison. As can be seen from the figure, when the generator speed torque feedforward control is turned on, the generator speed rising amplitude is obviously reduced.

[0079] Figure 7 For the generator speed feedforward control function being turned on and off, the generator speed time sequence comparison when the wind turbine is running in the variable speed interval. As can be seen from the figure, when the generator speed torque feedforward control is turned on, the generator speed fluctuation peak-to-peak value is obviously reduced, which is consistent with the foregoing frequency domain analysis.

[0080] Figure 8 The wind turbine output power time sequence comparison when the generator speed feedforward control function is opened and closed and the wind turbine runs in the variable speed interval. As can be seen from the figure, the average values of the two are very small.

[0081] Figure 9 The hub center thrust time sequence comparison when the generator speed feedforward control function is opened and closed and the wind turbine runs in the variable speed interval. As can be seen from the figure, when the generator speed torque feedforward control is opened, the peak-to-peak value of the hub center thrust fluctuation is obviously reduced.

[0082] Figure 10 The tower bottom My moment of inertia time sequence comparison when the generator speed feedforward control function is opened and closed and the wind turbine runs in the variable speed interval. As can be seen from the figure, when the generator speed torque feedforward control is opened, the peak-to-peak value of the tower bottom My moment of inertia fluctuation is obviously reduced, which is consistent with the foregoing frequency domain analysis.

[0083] Figure 11 The blade root flapwise My moment of inertia time sequence comparison when the generator speed feedforward control function is opened and closed and the wind turbine runs in the variable speed interval. As can be seen from the figure, when the generator speed torque feedforward control is opened, the peak-to-peak value of the blade root flapwise My moment of inertia fluctuation is obviously reduced, which is consistent with the foregoing frequency domain analysis.

[0084] Figure 12 The tower bottom My moment of inertia spectrum density comparison when the generator speed feedforward control function is opened and closed and the wind turbine runs in the variable speed interval. As can be seen from the figure, when the generator speed torque feedforward control is opened, the low-frequency component of the tower bottom My moment of inertia is obviously attenuated, which is consistent with the foregoing frequency domain analysis.

[0085] Figure 13 The blade root flapwise My moment of inertia spectrum density comparison when the generator speed feedforward control function is opened and closed and the wind turbine runs in the variable speed interval. As can be seen from the figure, when the generator speed torque feedforward control is opened, the low-frequency component of the blade root flapwise My moment of inertia is obviously attenuated, which is consistent with the foregoing frequency domain analysis.

[0086] Example 2

[0087] The embodiment discloses a wind turbine torque feedforward control system based on generator speed, which is used for implementing the wind turbine torque feedforward control method based on generator speed in the embodiment 1, as shown in the figure, the system comprises the following functional modules: Figure 14

[0088] The transmission module is used for sending the generator speed signal calculated by the frequency converter, i.e. the generator speed measurement value, to the main PLC of the wind turbine in real time when the wind turbine runs in the grid-connected power generation mode.

[0089] ​The first component acquisition module is configured to subtract the filtered value of the generator speed measurement value processed by the low-pass filter and the notch filter 1 from the generator speed given value, and the difference is taken as the input of the PI controller, and the output of the PI controller is taken as the first component of the generator electromagnetic torque given value.

[0090] The second component acquisition module is configured to subtract the filtered value of the generator speed measurement value processed by the low-pass filter and the notch filter 1 from the generator speed given value, and then process the difference by the phase-advance filter and the notch filter 2, when the wind turbine is running in the variable speed range below the rated wind speed, multiply the generator speed signal processed by the phase-advance filter and the notch filter 2 by the proportional gain, and then perform the amplitude limiting processing to obtain the electromagnetic torque compensation value of the generator speed torque feedforward control, which is taken as the second component of the generator electromagnetic torque given value.

[0091] The electromagnetic torque given value acquisition module is configured to superimpose the first component and the second component of the generator electromagnetic torque given value to obtain the electromagnetic torque given value of the wind turbine running in the variable speed range below the rated wind speed, and then send the electromagnetic torque given value to the frequency converter of the wind turbine for execution, so as to realize the desired electromagnetic torque value.

[0092] Embodiment 3

[0093] The embodiment discloses a storage medium, which stores a program, and when the program is executed by a processor, the wind turbine torque feedforward control method based on a generator speed is realized.

[0094] The storage medium in the embodiment can be a disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a U disk, a mobile hard disk, or the like.

[0095] Embodiment 4

[0096] The embodiment discloses a computing device, which comprises a processor and a memory for storing a program executable by the processor, and when the processor executes the program stored in the memory, the wind turbine torque feedforward control method based on a generator speed is realized.

[0097] The computing device in the embodiment can be a desktop computer, a notebook computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal devices with a processor function.

[0098] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application should be equivalent replacement manners and should be included in the protection scope of the present application.

Claims

1. A wind turbine torque feedforward control method based on generator speed, characterized in that: Do the following: When the wind turbine is operating in the grid-connected power generation mode, the generator speed signal calculated by the inverter, i.e. the generator speed measurement value, is sent to the main PLC of the wind turbine in real time; The main PLC subtracts the generator speed set value from the filtered value after the generator speed measurement value is processed by the low-pass filter and the notch filter 1. The difference is used as the input of the PI controller, and the output of the PI controller is used as the first component of the generator electromagnetic torque set value. The main PLC processes the difference between the generator speed measurement value after it has been processed by the low-pass filter and notch filter 1 and the generator speed set value, and then processes it through the phase advance filter and notch filter 2. When the wind turbine is operating in a variable speed range below the rated wind speed, the generator speed signal processed by the phase advance filter and notch filter 2 is multiplied by the proportional gain and then subjected to amplitude limiting processing to obtain the electromagnetic torque compensation value for the generator speed torque feedforward control, which serves as the second component of the generator electromagnetic torque set value. The main PLC superimposes the first component and the second component of the generator electromagnetic torque given value to obtain the electromagnetic torque given value of the wind turbine operating in the variable speed range below the rated wind speed, and then sends it to the frequency converter of the wind turbine for execution to achieve the desired electromagnetic torque value.

2. The wind turbine torque feedforward control method based on generator speed according to claim 1, characterized in that: The transfer function of the low-pass filter is as follows: or Where s is a complex variable, T1 is the time constant of the first-order low-pass filter, ξ3 is the damping ratio of the second-order low-pass filter, and ω3 is the cutoff frequency of the second-order low-pass filter.

3. The wind turbine torque feedforward control method based on generator speed according to claim 1, characterized in that: The transfer function of the notch filter 1 is as follows: Where s is a complex variable, ξ1 and ξ2 are the damping ratios of the notch filter, and ω1 and ω2 are the frequencies of the notch filter.

4. The wind turbine torque feedforward control method based on generator speed according to claim 1, characterized in that: The transfer function of the phase advance filter is as follows: Where s is a complex variable, a is the phase lead filter division coefficient, and T3 is the phase lead filter time constant.

5. The wind turbine torque feedforward control method based on generator speed according to claim 1, characterized in that: The transfer function of the notch filter 2 is as follows: Where s is a complex variable, ξ4 and ξ5 are the damping ratios of the notch filter, and ω4 and ω5 are the frequencies of the notch filter.

6. The wind turbine torque feedforward control method based on generator speed according to claim 1, characterized in that: The generator speed measurement value is sent to the main PLC of the wind turbine in real time via CANopen communication.

7. A wind turbine torque feedforward control system based on generator speed, characterized in that: A method for implementing a wind turbine torque feedforward control method based on generator speed according to any one of claims 1 to 6, comprising: The transmission module is used to send the generator speed signal calculated by the inverter, i.e. the generator speed measurement value, to the main PLC of the wind turbine in real time when the wind turbine is operating in the grid-connected power generation mode; a first component acquisition module, configured to subtract a filtered value of the generator speed measurement value processed by a low-pass filter and a notch filter 1 from the generator speed set value, and use the difference as an input to a PI controller, and use the output of the PI controller as a first component of the generator electromagnetic torque set value; A second component acquisition module is used to process the difference between the filtered value of the generator speed measurement value after being processed by the low-pass filter and the notch filter 1 and the generator speed set value, and then process it through the phase advance filter and the notch filter 2. When the wind turbine is operating in a variable speed range below the rated wind speed, the generator speed signal processed by the phase advance filter and the notch filter 2 is multiplied by the proportional gain and then subjected to a limiting process to obtain the electromagnetic torque compensation value for the generator speed torque feedforward control, which is used as the second component of the generator electromagnetic torque set value; The electromagnetic torque set value acquisition module is used to superimpose the first component and the second component of the generator electromagnetic torque set value to obtain the electromagnetic torque set value when the wind turbine is operating in the variable speed range below the rated wind speed, and then send it to the inverter of the wind turbine for execution to achieve the desired electromagnetic torque value.

8. A storage medium storing a program, characterized in that: When the program is executed by a processor, the wind turbine torque feedforward control method based on generator speed according to any one of claims 1 to 6 is implemented.

9. A computing device comprising a processor and a memory for storing a program executable by the processor, characterized in that: When the processor executes the program stored in the memory, the wind turbine torque feedforward control method based on generator speed according to any one of claims 1 to 6 is implemented.

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