A wind turbine generator master control method and system including an energy storage unit

Abstract

The application provides a wind turbine generator unit main control leading frequency modulation control method including an energy storage unit, based on Kalman filtering processing of a power grid frequency, and then performing segmented frequency average value processing on the filtered power grid frequency, so as to reduce the error of power grid frequency detection and shorten the frequency detection time; then, before the wind farm group controller issues a frequency modulation adjustment amount, the unit main control distributes an active power adjustment amount for primary frequency modulation and inertia response based on the frequency detection result, and controls the energy storage unit of the unit to perform primary frequency modulation and inertia response, so as to improve the frequency modulation response time. Meanwhile, the application also provides a wind turbine generator unit main control leading frequency modulation control system based on the control method.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, specifically to a main control and frequency regulation control method and system for wind turbine generators including an energy storage unit. Background Technology

[0002] The increasing penetration of new energy power generation in the power grid leads to weak inertia and weak frequency support in the grid system. Traditional wind turbines without energy storage often exhibit slow response times and difficulty meeting relevant regulations when performing primary frequency regulation and inertial response. When the grid frequency change rate (df / dt) or frequency (f) exceeds a threshold, the wind turbine should generate more or less active power to quickly respond to changes in grid frequency and reduce grid frequency fluctuations. According to the "Wind Turbine Grid Adaptability Test Procedure," the active power response time of the wind turbine's inertial response and primary frequency regulation function should not exceed 500ms. Figure 1 In this context, when the grid frequency fluctuates at t0, the time for the unit's active power response to reach the target value P1 from P0 cannot exceed 500ms.

[0003] When grid frequency fluctuations occur, traditional wind turbines without energy storage rely on the turbine's pitch system to control the blades to absorb or release more wind energy to regulate active power during primary frequency regulation and inertia response. However, relying solely on the pitch system for active power regulation is insufficient to meet the requirements for speed. The power response time of traditional wind turbines without energy storage consists of two significant components: frequency detection time and converter torque response time. Therefore, to improve the speed of active power response, an energy storage system is introduced. Due to the rapid energy release of the energy storage system, when the turbine needs to quickly perform primary frequency regulation and inertia response, the turbine's main control system can mobilize the energy storage system to increase or absorb the active power generated by the turbine. This necessitates a new frequency regulation control program based on the energy storage system to shorten the active power response time. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a wind turbine master control and frequency regulation control method and system including an energy storage unit, which at least solves the technical problem that a new frequency regulation control is needed to shorten the active power response time after the wind turbine is introduced into an energy storage system.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A first aspect of the present invention provides a main control method for frequency regulation of a wind turbine generator including an energy storage unit, comprising the following steps:

[0007] Collect the power grid frequency and filter it.

[0008] The filtered power grid frequency is divided into segments according to a set time interval, and the average frequency within each time interval is calculated. At the same time, the frequency change rate is calculated based on the calculated average frequency.

[0009] The active power regulation P1 is determined based on the obtained average frequency and frequency change rate.

[0010] A primary frequency modulation and inertia response are performed based on the active power adjustment P1.

[0011] Optionally, the filtering of the power grid frequency includes:

[0012] The power grid frequency is filtered based on the Kalman filter equation.

[0013] Optionally, calculating the average frequency over each time period includes:

[0014] Record the filtered frequency data point t0+it1 (where i = 1, 2, 3…) and the corresponding grid frequency value f(t0+it1). Calculate the average frequency within the time interval t1 using the following formula:

[0015]

[0016] Optionally, the frequency change rate calculated based on the obtained average frequency satisfies the following formula:

[0017]

[0018] Optionally, determining the active power adjustment P1 based on the calculated average frequency and frequency change rate includes:

[0019] Based on the comparison between the calculated average frequency and the set frequency range, if the average frequency exceeds the set frequency range, the active power adjustment amount P11 required to complete one frequency modulation is calculated.

[0020] Based on the comparison between the calculated frequency change rate and the set frequency change rate range, if the frequency change rate exceeds the set frequency change rate range, the active power adjustment P12 required to complete the inertial response is calculated.

[0021] Optionally, if the average frequency exceeds the set frequency range, the method further includes:

[0022] If the average frequency is greater than the maximum value of the set frequency range, the active power output of the wind turbine will be reduced and the active power will be absorbed by the energy storage unit of the unit.

[0023] If the average frequency is less than the minimum value of the set frequency range, the wind turbine will increase its active power output and the unit's energy storage unit will release active power.

[0024] Optionally, after performing a primary frequency modulation and inertia response based on the active power regulation P1, the method further includes:

[0025] If the wind farm group controller allocates an active power adjustment amount P2 to the current wind turbine group based on the power demand of the grid and the parameter differences of each wind turbine in the wind farm group, then the current frequency regulation strategy will be terminated and switched to primary frequency regulation and inertia response based on the active power adjustment amount P2.

[0026] A second aspect of the present invention provides a wind turbine master control and frequency regulation control system including an energy storage unit, comprising:

[0027] The acquisition unit is used to acquire the power grid frequency and filter the power grid frequency.

[0028] The processing unit is used to segment the filtered grid frequency according to a set time interval, calculate the average frequency within each time interval, and calculate the frequency change rate based on the calculated average frequency; it is also used to determine the active power regulation amount P1 based on the calculated average frequency and frequency change rate.

[0029] The energy storage unit is used to perform primary frequency regulation and inertia response based on the active power regulation amount P1.

[0030] Optionally, it also includes:

[0031] The wind farm control unit is used to allocate power adjustment amount P2 to the current wind turbine group based on the power demand of the grid and the parameter differences of each wind turbine;

[0032] The energy storage unit is used to terminate the current frequency regulation strategy and switch to primary frequency regulation and inertial response based on the active power regulation amount P2 after receiving the active power regulation amount P2 from the field group control unit.

[0033] As can be seen from the above technical solution, the beneficial effects of the present invention are as follows:

[0034] This invention provides a wind turbine master-controlled frequency regulation method including an energy storage unit. Based on Kalman filtering of the grid frequency, the method further performs segmented frequency averaging on the filtered grid frequency, reducing grid frequency detection errors and shortening frequency detection time. Then, before the wind farm group controller issues frequency regulation adjustments, the turbine master controller allocates active power adjustments for primary frequency regulation and inertial response based on the frequency detection results, and controls the turbine energy storage unit to perform primary frequency regulation and inertial response, improving the frequency regulation response time. Simultaneously, this invention also provides a wind turbine master-controlled frequency regulation control system including an energy storage unit based on this control method. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0036] Figure 1 This is the frequency curve after filtering;

[0037] Figure 2 The frequency curve is reconstructed based on the average frequency value;

[0038] Figure 3 Example curve of primary frequency regulation for wind turbine generators;

[0039] Figure 4 This is a schematic diagram of the power drop response to inertial response;

[0040] Figure 5 This is a schematic diagram of the power jump response to inertial response;

[0041] Figure 6 This is a flowchart of a wind turbine master control method that includes an energy storage unit and a dominant frequency regulation control method. Detailed Implementation

[0042] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0043] This invention provides a wind turbine master control method for main control and frequency regulation including an energy storage unit. Please refer to [link to relevant documentation]. Figure 6 It includes the following steps:

[0044] S1. Collect the power grid frequency and filter the power grid frequency;

[0045] S2. Divide the filtered power grid frequency into segments according to a set time interval, and calculate the average frequency within each time segment. At the same time, calculate the frequency change rate based on the calculated average frequency.

[0046] S3. Determine the active power regulation P1 based on the obtained average frequency and frequency change rate;

[0047] S4. Perform a primary frequency modulation and inertia response based on the active power adjustment amount P1.

[0048] The filtering of the power grid frequency includes: filtering the power grid frequency based on the Kalman filter equation. The core equation of the Kalman filter is:

[0049]

[0050] In Equation ①, X(k|k-1) is the result predicted using the previous state, X(k-1|k-1) is the optimal result of the previous state, and U(k) is the control variable of the current state. If there is no control variable, it can be 0.

[0051] In Equation ②, P(k|k-1) is the covariance of X(k|k-1), P(k-1|k-1) is the covariance of X(k-1|k-1), A' represents the transpose of A, and Q is the covariance of the system process.

[0052] In Equation ③, the optimal estimate of the current state (k) is X(k|k), where Kg is the Kalman gain;

[0053] Here, I is a matrix of 1s; for a single model and single measurement, I = 1. When the system enters state k+1, P(k|k) is P(k-1|k-1) in equation ②, thus allowing the algorithm to continue its autoregressive calculation. Based on these five formulas, it can be easily implemented using computer programming.

[0054] In one embodiment, calculating the average frequency within each time period includes dividing the frequency signal into segments according to a certain time interval, calculating the average frequency within each time segment, and thereby constructing a new frequency curve, such as... Figure 1 As shown, the filtered frequency data point t0+it1 (where i = 1, 2, 3…) and the corresponding grid frequency value f(t0+it1) are then recorded. The average frequency within the time interval t1 is calculated using the following formula:

[0055]

[0056] After the acquired frequencies are filtered, the average value is calculated to further eliminate errors. The frequency curve is then reconstructed using the calculated frequency points from the segmented average. Figure 2 As shown, the frequency slope, i.e., the frequency change rate df / dt, is then calculated using the frequency data of adjacent time intervals t1, using the following formula:

[0057]

[0058] To improve frequency regulation response speed, each renewable energy unit does not necessarily have to wait for the power plant controller to issue the frequency regulation adjustment before responding. Each unit can respond in advance according to its own set rules, and then exit its own response and execute the power plant controller's instructions after receiving the frequency regulation command from the power plant controller. Therefore, the main controller of each unit should determine the active power regulation P1 based on the calculated average frequency and frequency change rate, including:

[0059] Based on the comparison between the calculated average frequency and the set frequency range, if the average frequency exceeds the set frequency range, the active power adjustment P11 required to complete the primary frequency regulation is calculated; specifically, when the grid frequency decreases, the wind turbine should adjust the power according to the primary frequency regulation curve (e.g., ...). Figure 3 (As shown) The active power output is rapidly increased, and the unit's energy storage unit releases active power. When the active power regulation reaches 10%*Pn, it will no longer increase. When the system frequency rises, the wind turbine should rapidly reduce the active power output according to the primary frequency regulation curve, and the unit's energy storage unit absorbs active power. When the active power regulation reaches 20%Pn, it will no longer decrease.

[0060] Based on the comparison between the calculated frequency change rate and the set frequency change rate range, if the frequency change rate exceeds the set frequency change rate range, the active power adjustment P12 required to complete the inertial response is calculated.

[0061] For one example, please refer to Figure 3 The specific algorithm based on the active power adjustment amount P11 required for primary frequency regulation is as follows:

[0062] If the grid frequency is greater than f 21 (50.2Hz), then the power setpoint offset P11 is:

[0063]

[0064] In the formula, f represents the power grid frequency, f n Rated frequency, Pn rated power, K f The frequency regulation factor reflects the rate of change of active power; its value should be in the range of 5 to 20, with K being recommended. f1 For 10, K f2 It is 20;

[0065] If the grid frequency is greater than or equal to f 11 (49.8Hz), and less than or equal to f 21 (50.2Hz), then the power setpoint offset P11 is:

[0066] P11 = 0

[0067] If the grid frequency is less than f 11 (49.8Hz), then the power set offset P11 is:

[0068]

[0069] In the formula, f represents the power grid frequency, f n Rated frequency, Pn rated power, K f1 =10.

[0070] For another embodiment, please refer to Figure 4-5 The specific requirements for the active power regulation P12 required based on the inertial response are as follows:

[0071] When the frequency change rate at the test point exceeds the threshold, and the active power output of the wind turbine is greater than 20%Pn, the wind turbine should possess inertial response characteristics to quickly respond to changes in system frequency.

[0072] The active power response time should not exceed 500ms, and the active power regulation P12 should not be less than 10%Pn. During the power recovery process, if wind speed conditions permit, the difference between the minimum active power and the active power before the frequency change should not exceed 5%Pn. The frequency change rate threshold is determined by the power grid dispatching department, and it is recommended that the threshold be set to 0.3Hz / s during the test.

[0073] As a further improvement to the above scheme, after performing a primary frequency regulation and inertia response based on the active power regulation amount P1, the scheme further includes: if the wind farm group controller allocates an active power regulation amount P2 to the current wind turbine group based on the power demand of the grid and the parameter differences of each wind turbine group in the wind farm group, then the current frequency regulation strategy is terminated and switched to performing a primary frequency regulation and inertia response based on the active power regulation amount P2.

[0074] Based on the above control method, this invention also provides a wind turbine main control and frequency regulation control system including an energy storage unit, comprising:

[0075] The acquisition unit is used to acquire the power grid frequency and filter the power grid frequency.

[0076] The processing unit is used to segment the filtered grid frequency according to a set time interval, calculate the average frequency within each time interval, and calculate the frequency change rate based on the calculated average frequency; it is also used to determine the active power regulation amount P1 based on the calculated average frequency and frequency change rate.

[0077] The energy storage unit is used to perform primary frequency regulation and inertia response based on the active power regulation amount P1.

[0078] As a further improvement to the above solution, the control system further includes:

[0079] The wind farm control unit is used to allocate power adjustment amount P2 to the current wind turbine group based on the power demand of the grid and the parameter differences of each wind turbine;

[0080] The energy storage unit, upon receiving the active power regulation amount P2 from the power group control unit, terminates the current frequency regulation strategy and switches to primary frequency regulation and inertia response based on the active power regulation amount P2. Specifically, upon receiving the active power regulation amount P2, the unit immediately switches to P2 regardless of whether it has reached the active power regulation amount P1.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for main control and frequency regulation of a wind turbine generator including an energy storage unit, characterized in that, Includes the following steps: Collect the power grid frequency and filter it. The filtered power grid frequency is divided into segments according to a set time interval, and the average frequency within each time interval is calculated. At the same time, the frequency change rate is calculated based on the calculated average frequency. The step of calculating the average frequency within each time period includes: Record the frequency data points after filtering. (in ), and the corresponding power grid frequency value for that frequency data point. Calculate the time interval The average value of the internal frequency is calculated using the following formula: ； The frequency change rate calculated based on the obtained average frequency value satisfies the following formula: ； The active power regulation P1 is determined based on the calculated average frequency and frequency change rate, including: Based on the comparison between the calculated average frequency and the set frequency range, if the average frequency exceeds the set frequency range, the active power adjustment amount P11 required to complete one frequency modulation is calculated. Based on the comparison between the calculated frequency change rate and the set frequency change rate range, if the frequency change rate exceeds the set frequency change rate range, the active power adjustment P12 required to complete the inertial response is calculated. A primary frequency modulation and inertia response are performed based on the active power adjustment P1.

2. The wind turbine master control method including an energy storage unit according to claim 1, characterized in that, The filtering process for the power grid frequency includes: The power grid frequency is filtered based on the Kalman filter equation.

3. The wind turbine master control method for frequency regulation including an energy storage unit according to claim 1, characterized in that, If the average frequency exceeds the set frequency range, the method further includes: If the average frequency is greater than the maximum value of the set frequency range, the active power output of the wind turbine will be reduced and the active power will be absorbed by the energy storage unit of the unit. If the average frequency is less than the minimum value of the set frequency range, the wind turbine will increase its active power output and the unit's energy storage unit will release active power.

4. The wind turbine master control method including an energy storage unit according to claim 1, characterized in that, After performing a primary frequency modulation and inertia response based on the active power regulation P1, the process further includes: If the wind farm group controller allocates an active power adjustment amount P2 to the current wind turbine group based on the power demand of the grid and the parameter differences of each wind turbine in the wind farm group, then the current frequency regulation strategy will be terminated and switched to primary frequency regulation and inertia response based on the active power adjustment amount P2.

5. A wind turbine master control and frequency regulation control system including an energy storage unit, employing the wind turbine master control and frequency regulation control method including an energy storage unit as described in any one of claims 1-4, characterized in that, include: The acquisition unit is used to acquire the power grid frequency and filter the power grid frequency. The processing unit is used to segment the filtered grid frequency according to a set time interval, calculate the average frequency within each time interval, and calculate the frequency change rate based on the calculated average frequency; it is also used to determine the active power regulation amount P1 based on the calculated average frequency and frequency change rate. The energy storage unit is used to perform primary frequency regulation and inertia response based on the active power regulation amount P1.

6. A wind turbine main control and frequency regulation control system including an energy storage unit according to claim 5, characterized in that, Also includes: The wind farm control unit is used to allocate power adjustment amount P2 to the current wind turbine group based on the power demand of the grid and the parameter differences of each wind turbine; The energy storage unit is used to terminate the current frequency regulation strategy and switch to primary frequency regulation and inertial response based on the active power regulation amount P2 after receiving the active power regulation amount P2 from the field group control unit.

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