A feedforward control method and system for wind turbine generator set based on generator speed

Abstract

The present invention discloses a feedforward control method and system for a wind turbine generator set based on generator speed. When the unit is operating in grid-connected power generation mode, the generator speed measurement value calculated by the frequency converter is sent to the main PLC. The generator speed measurement value is filtered and then subtracted from the generator speed set value. The difference is input to a PI proportional-integral controller, which outputs the first component of the blade angle set value. The generator speed measurement value is filtered and then phase-compensated. When the unit is operating at rated speed and rated power, the compensated generator speed signal is multiplied by the proportional gain to obtain the second component of the blade angle set value. The first and second components are superimposed to obtain the final blade angle set value, which is then sent to the blade pitch control mechanism for execution to achieve the desired blade angle value. The present invention can reduce tower fatigue loads and blade fatigue loads, as well as reduce the occurrence of generator speed overspeed faults.

Description

Technical Field

[0001] The present invention relates to the technical field of feedforward control of wind turbine generator sets, and in particular to a feedforward control method, system, storage medium and computing device for wind turbine generator sets based on generator speed. Background Art

[0002] As wind power generation reaches grid parity, reducing the load on key mechanical components of wind turbines, and thereby lowering their costs, is becoming a trend. Feedforward control strategies, using lidar to measure wind speed, are widely used in large-capacity wind turbines to reduce tower fatigue loads and associated costs. Furthermore, suppressing generator speed fluctuations reduces the risk of overspeed failures. However, the current cost of a single nacelle-mounted lidar unit typically exceeds 100,000 yuan, making its application costly. Summary of the Invention

[0003] The first purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and provide a feedforward control method for a wind turbine generator set based on the generator speed. When the wind turbine generator set is operating in the range above the rated speed and rated power, on the one hand, the frequency components below 0.1Hz in the bending moment signal in the front and rear directions of the wind turbine generator set tower are greatly attenuated, thereby greatly reducing the fatigue load of the tower; on the other hand, the maximum operating speed of the generator in the power generation mode is reduced, thereby greatly reducing the occurrence of generator speed overspeed failures and improving the operating reliability of the wind turbine generator set.

[0004] A second object of the present invention is to provide a feedforward control system for a wind turbine generator set based on the generator speed.

[0005] A third object of the present invention is to provide a storage medium.

[0006] A fourth object of the present invention is to provide a computing device.

[0007] The first object of the present invention is achieved by the following technical solution: a feedforward control method for a wind turbine generator set based on generator speed, performing the following operations:

[0008] When the wind turbine generator set operates 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 generator set in real time;

[0009] The main PLC filters the generator speed measurement value through notch filter 1 and low-pass filter 1 in sequence, and then subtracts the filtered value from the generator speed set value. The difference is used as the input of the PI proportional-integral controller, and the output of the PI proportional-integral controller is used as the first component of the blade angle set value;

[0010] The main PLC filters the generator speed measurement value through notch filter 2 and low-pass filter 2 in sequence, and then passes the filtered value through phase compensation processing of the phase compensator. When the wind turbine generator set operates at rated speed and rated power, the generator speed signal after phase compensation is multiplied by the proportional gain to obtain the blade angle compensation value for the generator speed feedforward control, which is used as the second component of the blade angle set value;

[0011] The main PLC superimposes the first component and the second component of the blade angle set value to obtain the final blade angle set value when the wind turbine is running at the rated speed and rated power, and then sends it to the blade pitch mechanism of the wind turbine for execution to achieve the desired blade angle value.

[0012] Furthermore, the transfer function of the notch filter 1 is as follows:

[0013]

[0014] 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. Furthermore, the transfer function of the low-pass filter 1 is as follows:

[0015] or

[0016] 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.

[0017] Furthermore, the transfer function of the notch filter 2 is as follows:

[0018]

[0019] 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. Further, the transfer function of the low-pass filter 2 is as follows:

[0020] or

[0021] Where s is a complex variable, T2 is the time constant of the first-order low-pass filter, ξ6 is the damping ratio of the second-order low-pass filter, and ω6 is the cutoff frequency of the second-order low-pass filter.

[0022] Furthermore, the transfer function of the phase compensator is as follows:

[0023]

[0024] Where s is a complex variable, a is the phase compensator division coefficient, and T3 is the phase compensator time constant.

[0025] The second object of the present invention is achieved by the following technical solution: a wind turbine generator set feedforward control system based on generator speed, used to implement the above-mentioned wind turbine generator set feedforward control method based on generator speed, comprising:

[0026] The sending 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;

[0027] A first component acquisition module is used to filter the generator speed measurement value through notch filter 1 and low-pass filter 1 in sequence, and then subtract the filtered value from the generator speed set value. The difference is used as the input of the PI proportional-integral controller, and the output of the PI proportional-integral controller is used as the first component of the blade angle set value;

[0028] A second component acquisition module is used to filter the generator speed measurement value through the notch filter 2 and the low-pass filter 2 in sequence, and then subject the filtered value to phase compensation processing by the phase compensator. When the wind turbine generator set operates at the rated speed and rated power, the generator speed signal after phase compensation is multiplied by the proportional gain to obtain the blade angle compensation value for the generator speed feedforward control as the second component of the blade angle set value;

[0029] The blade angle set value acquisition module is used to superimpose the first component and the second component of the blade angle set value to obtain the final blade angle set value when the wind turbine generator set operates at the rated speed and rated power, and then send it to the blade pitch control mechanism of the wind turbine generator set for execution to achieve the desired blade angle value.

[0030] The third object of the present invention is achieved through the following technical solution: a storage medium stores a program, and when the program is executed by a processor, the above-mentioned wind turbine generator set feedforward control method based on generator speed is implemented.

[0031] The fourth purpose of the present invention is achieved through the following technical solution: a computing device, comprising a processor and a memory for storing a program executable by the processor, wherein when the processor executes the program stored in the memory, the above-mentioned feedforward control method of the wind turbine generator set based on the generator speed is implemented.

[0032] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] 1. Without increasing any cost, by attenuating the frequency components below 0.1Hz in the bending moment signal in the front-to-rear direction of the wind turbine tower, the fatigue load of the tower and the cost of the entire wind turbine are reduced.

[0034] 2. Without increasing any cost, reduce the maximum generator speed when the wind turbine is operating in the rated speed and rated power range, thereby reducing the occurrence of generator speed overspeed failures and improving the unit's operating reliability.

[0035] 3. Reduce blade fatigue load without increasing any cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the method of the present invention.

[0037] Figure 2 This is a timing comparison diagram of the generator speed when the generator speed feedforward control function is turned on and off.

[0038] Figure 3 This is a timing comparison diagram of the unit (also called fan) output power when the generator speed feedforward control function is turned on and off.

[0039] Figure 4 This is a comparison diagram of the blade angle timing when the generator speed feedforward control function is turned on and off.

[0040] Figure 5 This is a timing comparison diagram of the bending moment My at the bottom of the tower when the generator speed feedforward control function is turned on and off.

[0041] Figure 6 This is a comparison diagram of the thrust timing of the unit (also called a fan) when the generator speed feedforward control function is turned on and off.

[0042] Figure 7 Comparison of the My bending moment spectrum density at the tower bottom when the generator speed feedforward control function is turned on and off.

[0043] Figure 8 This is an architectural diagram of the system of the present invention. DETAILED DESCRIPTION

[0044] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0045] Example 1

[0046] like Figure 1 As shown, this embodiment discloses a feedforward control method for a wind turbine generator set based on generator speed, which performs the following operations:

[0047] When the wind turbine is operating in 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 via CANopen or other communication methods;

[0048] The main PLC filters the generator speed measurement value through notch filter 1 and low-pass filter 1 in sequence, and then subtracts the filtered value from the generator speed set value. The difference is used as the input of the PI proportional-integral controller, and the output of the PI proportional-integral controller is used as the first component of the blade angle set value;

[0049] The main PLC filters the generator speed measurement value through notch filter 2 and low-pass filter 2 in sequence, and then passes the filtered value through phase compensation processing of the phase compensator. When the wind turbine generator set operates at rated speed and rated power, the generator speed signal after phase compensation is multiplied by the proportional gain to obtain the blade angle compensation value for the generator speed feedforward control, which is used as the second component of the blade angle set value;

[0050] The main PLC superimposes the first component and the second component of the blade angle set value to obtain the final blade angle set value when the wind turbine is running at the rated speed and rated power, and then sends it to the blade pitch mechanism of the wind turbine for execution to achieve the desired blade angle value.

[0051] Specifically, the transfer function of the notch filter 1 is as follows:

[0052]

[0053] 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. Specifically, the transfer function of the low-pass filter 1 is as follows:

[0054] or

[0055] 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.

[0056] Specifically, the transfer function of the notch filter 2 is as follows:

[0057]

[0058] 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. Specifically, the transfer function of the low-pass filter 2 is as follows:

[0059] or

[0060] Where s is a complex variable, T2 is the time constant of the first-order low-pass filter, ξ6 is the damping ratio of the second-order low-pass filter, and ω6 is the cutoff frequency of the second-order low-pass filter.

[0061] Specifically, the transfer function of the phase compensator is as follows:

[0062]

[0063] Where s is a complex variable, a is the phase compensator division coefficient, and T3 is the phase compensator time constant.

[0064] Figure 2 The following figure compares the generator speed when the generator speed feedforward control function is enabled and disabled. As can be seen from the figure, when the generator speed feedforward control function is enabled, the instantaneous generator speed value is smaller and the peak-to-peak fluctuation is also smaller, which is more beneficial for suppressing the occurrence of generator overspeed faults.

[0065] Figure 3 This chart compares the unit (also known as the fan) output power when the generator speed feedforward control function is enabled and disabled. As can be seen from the figure, the 10-minute average difference in the unit output power between the two schemes is relatively small.

[0066] Figure 4 A comparison of blade angles when the generator speed feedforward control function is enabled and disabled is shown in the figure. As can be seen, when the generator speed feedforward control function is enabled, the blade angles are in a phase-leading state, and no additional pitch control action is significantly added, achieving the feedforward control effect.

[0067] Figure 5 、 Figure 6 Comparisons of the My bending moment signal at the tower base and the turbine (also known as the wind turbine) thrust signal are shown below, respectively, when the generator speed feedforward control function is enabled and disabled. The figures show that when the generator speed feedforward control function is enabled, the peak-to-peak value of the low-frequency oscillation components in the turbine thrust and My bending moment signals at the tower base are smaller, indicating less fatigue load on the tower.

[0068] Figure 7 This figure compares the bending moment spectral density of My at the tower base when the generator speed feedforward control function is enabled and disabled. The figure shows that when the generator speed feedforward control function is enabled, the low-frequency components below 0.1 Hz are significantly attenuated compared to when the generator speed feedforward control function is disabled, meeting design expectations.

[0069] Example 2

[0070] This embodiment discloses a feedforward control system for a wind turbine generator set based on generator speed, which is used to implement the feedforward control method for a wind turbine generator set based on generator speed described in Example 1. Figure 8 As shown, the system includes the following functional modules:

[0071] The sending 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;

[0072] A first component acquisition module is used to filter the generator speed measurement value through notch filter 1 and low-pass filter 1 in sequence, and then subtract the filtered value from the generator speed set value. The difference is used as the input of the PI proportional-integral controller, and the output of the PI proportional-integral controller is used as the first component of the blade angle set value;

[0073] A second component acquisition module is used to filter the generator speed measurement value through the notch filter 2 and the low-pass filter 2 in sequence, and then subject the filtered value to phase compensation processing by the phase compensator. When the wind turbine generator set operates at the rated speed and rated power, the generator speed signal after phase compensation is multiplied by the proportional gain to obtain the blade angle compensation value for the generator speed feedforward control as the second component of the blade angle set value;

[0074] The blade angle set value acquisition module is used to superimpose the first component and the second component of the blade angle set value to obtain the final blade angle set value when the wind turbine generator set operates at the rated speed and rated power, and then send it to the blade pitch control mechanism of the wind turbine generator set for execution to achieve the desired blade angle value.

[0075] Example 3

[0076] This embodiment discloses a storage medium storing a program. When the program is executed by a processor, the feedforward control method for a wind turbine generator set based on generator speed described in Example 1 is implemented.

[0077] The storage medium in this embodiment can be a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a USB flash drive, a mobile hard disk, or the like.

[0078] Example 4

[0079] This embodiment discloses a computing device, including a processor and a memory for storing a program executable by the processor. When the processor executes the program stored in the memory, the feedforward control method for a wind turbine generator set based on generator speed described in Example 1 is implemented.

[0080] The computing device described in this embodiment may be a desktop computer, a laptop computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal devices with a processor function.

[0081] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A feedforward control method for a wind turbine generator set based on generator speed, characterized in that: Do the following: When the wind turbine generator set operates 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 generator set in real time; The main PLC filters the generator speed measurement value through the first notch filter and the first low-pass filter in sequence, and then subtracts the filtered value from the generator speed set value. The difference is used as the input of the PI proportional-integral controller, and the output of the PI proportional-integral controller is used as the first component of the blade angle set value. The main PLC filters the generator speed measurement value through the second notch filter and the second low-pass filter in sequence, and then processes the filtered value through the phase compensator for phase compensation. When the wind turbine generator set operates at the rated speed and rated power, the generator speed signal after phase compensation is multiplied by the proportional gain to obtain the blade angle compensation value for the generator speed feedforward control, which serves as the second component of the blade angle set value. The main PLC superimposes the first component and the second component of the blade angle set value to obtain the final blade angle set value when the wind turbine is running at the rated speed and rated power, and then sends it to the blade pitch mechanism of the wind turbine for execution to achieve the desired blade angle value.

2. The feedforward control method for a wind turbine generator set based on generator speed according to claim 1, characterized in that: The transfer function of the first notch filter 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.

3. The feedforward control method for a wind turbine generator set based on generator speed according to claim 1, characterized in that: The transfer function of the first 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.

4. The feedforward control method for a wind turbine generator set based on generator speed according to claim 1, characterized in that: The transfer function of the second notch filter 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.

5. The feedforward control method for a wind turbine generator set based on generator speed according to claim 1, characterized in that: The transfer function of the second low-pass filter is as follows: or Where s is a complex variable, T2 is the time constant of the first-order low-pass filter, ξ6 is the damping ratio of the second-order low-pass filter, and ω6 is the cutoff frequency of the second-order low-pass filter.

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

7. A feedforward control system for a wind turbine generator set based on generator speed, characterized in that: A feedforward control method for a wind turbine generator set based on generator speed according to any one of claims 1 to 6, comprising: The sending 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 filter the generator speed measurement value through a first notch filter and a first low-pass filter in sequence, and then subtract the filtered value from the generator speed set value, with the difference serving as the input of a PI proportional-integral controller, and the output of the PI proportional-integral controller serving as the first component of the blade angle set value; A second component acquisition module is used to filter the generator speed measurement value through a second notch filter and a second low-pass filter in sequence, and then subject the filtered value to phase compensation processing by a phase compensator. When the wind turbine generator set operates at rated speed and rated power, the generator speed signal after phase compensation is multiplied by a proportional gain to obtain a blade angle compensation value for generator speed feedforward control as the second component of the blade angle set value; The blade angle set value acquisition module is used to superimpose the first component and the second component of the blade angle set value to obtain the final blade angle set value when the wind turbine generator set operates at the rated speed and rated power, and then send it to the blade pitch control mechanism of the wind turbine generator set for execution to achieve the desired blade angle value.

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

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