Nonlinear position and speed estimation method and device based on disturbance observation of wind generating set

Abstract

The invention discloses a position and speed nonlinear estimation method and device based on disturbance observation of a wind generating set. The method comprises the following steps: 1, measuring rotor position information of a motor through an encoder; step 2, subtracting the rotor position information obtained in the step 1 from a rotor position estimation value to obtain a rotor position error signal; the rotor position estimation value is the rotor position information estimated by the nonlinear extended state observer in the step 4; 3, designing a proper nonlinear function for the nonlinear expansion state observer; and 4, constructing a third-order nonlinear extended state observer based on the error signal in the step 2 and the nonlinear function in the step 3, and estimating the position and the speed of the fan. Compensation of internal and external disturbances of the system is realized, and the position and speed of the wind driven generator are estimated.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind turbine control, and particularly relates to a method and device for non-linear estimation of position and speed based on disturbance observation of a wind turbine generator set. Background Art

[0002] In the control of variable-speed constant-frequency wind turbine generator sets, in order to capture more wind energy and implement the maximum power point tracking technology, the rotation speed of the wind turbine is usually controlled to maintain the optimal tip speed ratio, thereby maintaining the maximum wind energy utilization coefficient. However, the environment where the wind turbine generator set is located is usually relatively complex. The drastic change in wind speed causes frequent changes in the wind turbine load, and the load disturbance further causes large fluctuations in the rotation speed of the wind turbine. In the rotation speed control strategy of the wind turbine generator set, in order to ensure the stable operation of the wind turbine and improve the anti-disturbance ability, accurate rotor position and rotation speed information are required, which poses a challenge to the position and speed detection technology of the wind turbine.

[0003] Traditional methods measure the position information of the rotor through a high-precision encoder, and then perform differential calculation on the position of the rotor to obtain the rotation speed of the generator, which is used as feedback in the closed-loop control of the rotation speed of the wind turbine generator set. However, this position differential method has certain limitations in the complex environment of wind turbine operation. When the wind turbine load changes frequently and the rotation speed fluctuates greatly, the anti-disturbance ability of this method is poor and the dynamic performance is insufficient, making it difficult to suppress the rotation speed fluctuation of the wind turbine, and having an adverse impact on the stable operation of the wind turbine generator.

[0004] In order to suppress the disturbance of the rotation speed, the authors Zhou Dongdong et al. published a literature "Design and Implementation of a Rotation Speed Adaptive Filtering Algorithm for Wind Turbine Generator Sets" in "Ship Engineering" in 2024, which proposed a rotation speed adaptive filtering method for wind turbine generator sets to eliminate the influence of rotation speed disturbance. However, the introduction of the filter will cause time-domain delay and weaken its anti-disturbance ability.

[0005] In summary, the existing wind turbine position and rotation speed measurement technologies have obvious disadvantages. In the case of drastic changes in wind turbine load, the measurement accuracy of the existing methods is significantly insufficient, and their anti-disturbance ability is poor, making it difficult to achieve stable control of the wind turbine rotation speed. Summary of the Invention

[0006] In order to overcome the above deficiencies of the existing technologies, the purpose of the present invention is to provide a method and device for non-linear estimation of position and speed based on disturbance observation of a wind turbine generator set, in order to improve the anti-disturbance ability of the wind turbine generator and improve the control accuracy of its rotation speed. The present invention first extracts the rotor position and designs the non-linear function, then constructs a third-order non-linear extended state observer, and finally realizes the compensation of internal and external disturbances of the system and estimates the position and speed of the wind turbine generator.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A non-linear estimation method for position and speed based on disturbance observation of a wind turbine generator set, comprising the following steps;

[0009] Step 1, measure the rotor position information of the motor through an encoder;

[0010] Step 2, subtract the rotor position information obtained in Step 1 from the rotor position estimated value to obtain a rotor position error signal; this step depends on the integrity of the closed-loop system, and the rotor position estimated value is the rotor position information estimated by the non-linear extended state observer in Step 4;

[0011] Step 3, design a suitable non-linear function for the non-linear extended state observer;

[0012] Step 4, based on the error signal in Step 2 and the non-linear function in Step 3, construct a third-order non-linear extended state observer to estimate the position and speed of the wind turbine.

[0013] The encoder in Step 1 is an optoelectronic encoder.

[0014] In Step 1, the encoder is installed on the bearing of the wind turbine generator.

[0015] In Step 2, the formula for the position error signal e is:

[0016]

[0017] where: θ is the position measured by the encoder, is the rotor position estimated by the non-linear extended state observer in Step 4.

[0018] In Step 2, the position information estimated in Step 4 is used as a feedback quantity, subtracted from the measured position, and a new position estimated value is obtained through updating by the extended state observer; when running for the first time, the position estimated value has not been obtained yet, that is, its initial value is unknown (usually zero), so there is a large error between the two. The role of the closed-loop system makes the estimated value converge quickly, and finally makes the estimated value tend to the measured value.

[0019] In Step 3, the expression of the non-linear function fal(e, α, δ) is:

[0020]

[0021] where: α is a non-linear factor, and its value range is (0 to 1); δ is a linear threshold value used to determine the small error linear interval of the function; sign(e) is a sign function, expressed as:

[0022]

[0023] Step 4 is specifically as follows: The third-order nonlinear observer is of single-input and double-output type, and the specific formula of the constructed observer is:

[0024]

[0025] Where: is the estimated value of the rotor position derivative of; is the estimated value of the wind turbine speed estimated value of; is the estimated value of the system disturbance derivative of; β1, β2, and β3 are observer gain parameters; y1 and y2 are the output variables of the observer.

[0026] A device for non-linear estimation of position and speed based on disturbance observation of a wind power generation set, including an encoder on the wind turbine shaft, where the encoder is used to collect the position information of the generator and input it into the microcontroller for calculation to complete the non-linear estimation method of position and speed based on state expansion observation and load disturbance compensation of the wind power generation set.

[0027] The encoder is an optoelectronic encoder and is installed on the bearing of the wind turbine;

[0028] The microcontroller unit operates the above non-linear estimation method of position and speed based on state expansion observation and load disturbance compensation of the wind power generation set according to the steps, and calculates the motor position and speed information.

[0029] Advantages of the present invention:

[0030] The present invention provides a non-linear estimation method and device for position and speed based on disturbance observation of a wind power generation set. Compared with the traditional wind turbine position and speed estimation methods, the present invention is based on a third-order non-linear extended state observer, takes the internal and external disturbances of the control system as observation variables, and compensates for the internal and external disturbances of the system through non-linear functions. Therefore, it can improve the anti-disturbance ability of the wind power generation set in an environment with drastic wind speed changes, improve the estimation accuracy of the wind power generation set speed, enable the wind turbine to improve the accuracy of its speed control in a situation with strong load mutations, and maintain the smoothness of its operation. Description of the Drawings

[0031] Figure 1 is the flow chart of the estimation method for the position and speed of the wind turbine implemented and provided by the present invention.

[0032] Figure 2 is the complete closed-loop control block diagram of the wind turbine position and speed estimation method based on the non-linear extended state observer proposed by the present invention. Detailed implementation manners

[0033] The present invention will be further described in detail below with reference to the accompanying drawings.

[0034] As Figure 1 shown, a method for non-linear estimation of position and speed based on disturbance observation of a wind turbine generator set includes the following steps;

[0035] Step 1, collect the position information θ of the wind turbine generator set through an encoder;

[0036] The encoder is an optoelectronic encoder and is installed on the bearing of the wind turbine;

[0037] Step 2, this step depends on the integrity of the closed-loop system. Subtract the position information θ measured in Step 1 from the position estimated in Step 4 to obtain a position error signal e; use the position information estimated in Step 4 as a feedback quantity, subtract it from the measured position, and update through an extended state observer to obtain a new position estimate value. Although the position estimate value has not been obtained during the first run, that is, its initial value is unknown (usually zero), so there is a large error between the two. The role of the closed-loop system makes the estimate value converge quickly, and finally makes the estimate value tend to the measured value. The closed-loop structure is shown in Figure 2 .

[0038]

[0039] Where: θ is the position measured by the encoder, is the rotor position estimated by the non-linear extended state observer in Step 4.

[0040] Step 3, to construct a non-linear extended state observer, design a non-linear function fal(e, α, δ);

[0041]

[0042] Where: α is a non-linear factor, and its value range is (0 to 1); δ is a linear threshold used to determine the small-error linear interval of the function; sign(e) is a sign function, expressed as:

[0043]

[0044] This function is mainly used to determine and output the sign of the variable, ensure the consistency between the output result of the non-linear function and the error direction, and at the same time enhance the non-linear characteristics of the function and improve the robustness of the control system.

[0045] Step 4, construct a non-linear extended state observer to estimate the position and speed of the wind turbine.

[0046] The third-order nonlinear observer designed in the present invention is of the single-input and double-output type, and the specific formula of the constructed observer is as follows:

[0047]

[0048] Where: is the estimated value of the rotor position the derivative of; is the estimated value of the fan speed the estimated value of; is the estimated value of the system disturbance the derivative of; β1, β2, and β3 are the observer gain parameters; y1 and y2 are the output variables of the observer.

[0049] In the second step of the present invention, the initial error signal should be the error between the initial encoder measurement value and the initial estimated value. During the first operation, since the estimated value has not been obtained yet, it can usually be initialized to zero. As a result, an error signal is generated between the two, and based on the principle that the closed-loop system eliminates the error based on the error, the estimated value converges to near the actual measurement value.

[0050] Based on the third-order nonlinear extended state observer, the present invention regards the internal and external disturbances of the control system as the observed variables and compensates for the internal and external disturbances of the system through a nonlinear function. Therefore, it can improve the anti-disturbance ability of the wind turbine generator in an environment with drastic wind speed changes, improve the estimation accuracy of the wind turbine generator speed, enable the wind turbine to improve the accuracy of its speed control in a situation with strong load mutations, and maintain the smoothness of its operation.

[0051] The above specific process is only an actual application routine of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention and should not be limited to the content involved in the above routine of the present invention.

Claims

1. A non - linear estimation method for position and velocity based on disturbance observation of a wind turbine generator set, characterized in that, Including the following steps; Step 1, obtaining the rotor position information of the motor through encoder measurement; Step 2, subtracting the rotor position information obtained in Step 1 from the rotor position estimated value to obtain a rotor position error signal; the rotor position estimated value is the rotor position information estimated by the nonlinear extended state observer in Step 4; Step 3, designing a suitable nonlinear function for the nonlinear extended state observer; Step 4, based on the error signal in Step 2 and the nonlinear function in Step 3, constructing a third-order nonlinear extended state observer to estimate the position and speed of the wind turbine.

2. The position and velocity nonlinear estimation method based on disturbance observation of a wind turbine generator set according to claim 1, characterized in that The encoder in Step 1 is an optoelectronic encoder.

3. A position and velocity non-linear estimation method based on disturbance observation of a wind turbine generator set according to claim 1, characterized in that In Step 1, the encoder is installed on the bearing of the wind turbine generator.

4. A method for non - linear estimation of position and speed based on disturbance observation of a wind turbine generator set according to claim 1, characterized in that, In Step 2, the formula for the position error signal e is: where: θ is the position measured by the encoder, which is the rotor position estimated by the non-linear extended state observer in step 4.

5. A position and velocity nonlinear estimation method based on disturbance observation of a wind turbine generator set according to claim 1, characterized in that, In Step 2, the position information estimated in Step 4 is used as the feedback quantity, subtracted from the measured position, and a new position estimated value is obtained through the update of the extended state observer; when running for the first time, the position estimated value has not been obtained yet, that is, its initial value is unknown, and there is a large error between the two. The role of the closed-loop system makes the estimated value converge quickly and finally makes the estimated value tend to the measured value.

6. A method for non-linear estimation of position and speed based on wind turbine disturbance observation according to claim 1, characterized in that, In Step 3, the expression of the nonlinear function fal(e, α, δ) is: Where: α is the nonlinear factor, and its value range is (0 to 1); δ is the linear threshold, which is used to determine the small-error linear interval of the function; sign(e) is the sign function, which is expressed as:

7. A method for non-linear estimation of position and speed based on disturbance observation of a wind turbine generator set according to claim 1, characterized in that, Step 4 is specifically: the third-order nonlinear observer is of the single-input and double-output type, and the specific formula of the constructed observer is: Wherein: is the estimated value of the rotor position derivative; is the estimated value of the fan speed estimated value; is the estimated value of the system disturbance derivative; β1, β2, β3 are observer gain parameters; y1 and y2 are the output variables of the observer.

8. A position and velocity nonlinear estimation device based on disturbance observation of a wind turbine generator set, characterized in that Including an encoder on the shaft of the wind turbine generator, the encoder is used to collect the position information of the generator and input it into the microcontroller for calculation, so as to complete the position and speed nonlinear estimation method based on the disturbance observation of the wind turbine set according to any one of claims 1-7.

9. The position and speed non-linear estimation device based on disturbance observation of a wind turbine generator set according to claim 8, characterized in that, The encoder is an optoelectronic encoder and is installed on the bearing of the wind turbine generator.

10. A position and velocity nonlinear estimation device based on disturbance observation of a wind turbine generator set according to claim 8, characterized in that, The microcontroller unit operates the position and speed nonlinear estimation method based on the disturbance observation of the wind turbine set according to any one of claims 1-7 according to the steps, and calculates the motor position and speed information.

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