A method for processing generator speed in a wind turbine generator control system

Abstract

The present invention relates to the field of wind power generation, and specifically discloses a generator speed processing method for a wind power generator control system, including: detecting a function flag to confirm; collecting the original and filtered generator speeds, and setting the original cutoff frequency; selecting multiple generator speeds to compare with the original generator speed, and starting timing when the generator speed is equal to the original generator speed, and the generator speed is equal to the filtered generator speed, and obtaining multiple marked times; setting a delay threshold parameter, and scheduling the generator speed filter cutoff frequency. The present invention analyzes and judges the delay of the original generator speed and the filtered generator speed, so as to schedule the cutoff frequency for filtering the original generator speed, and avoid the problem of wind power generator control delay caused by excessive delay between the filtered generator speed participating in the control input and the actual generator speed.

Description

Technical Field

[0001] The invention relates to the field of wind power generation, and in particular to a generator speed processing method for a wind power generator set control system. Background Art

[0002] The rotor of a horizontal axis wind turbine absorbs wind energy and rotates, which in turn drives the connected generator to rotate and generate electricity. The control strategy of a wind turbine requires a series of sensors to detect signals, which are then passed to the core control strategy through a specific algorithm for control command calculation. In particular, the generator speed is an important input for the pitch control and torque control of a wind turbine. Its real-time performance plays a critical role in the real-time operation and control of a wind turbine. Since the generator speed measurement is generally controlled by hardware such as proximity switches or the generator speed feedback from the converter as the control input, its signal is often mixed with some high-order frequency components in the frequency domain. The actual wind turbine does not need to respond to these high-order frequency components. Therefore, the usual practice is to filter the measured generator speed signal and only retain the generator speed signal with a lower frequency for introduction into the control. However, since different brands of converters consider different control algorithms, the filter cutoff frequencies used are not the same, resulting in different generator speed delays after filtering, which affects the control effect of the wind turbine control system.

[0003] Existing technical solutions to this problem include: only considering the cutoff frequency requirements in the converter control algorithm, and not fully considering the delay between the filtered generator speed and the actual generator speed, resulting in the failure to respond in time to the generator speed changes caused by wind speed changes through pitch control and other methods, causing large components of the unit to be unevenly loaded when the wind speed changes drastically, and fatigue damage and extreme loads are likely to occur during long-term operation. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a generator speed processing method for a wind turbine control system to solve the problem of wind turbine control delay caused by excessive delay between the filtered generator speed participating in the control input and the actual generator speed.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a generator speed processing method for a wind turbine generator control system, comprising:

[0007] S1: Confirmation of the detection function flag within the detection cycle;

[0008] S2: Collect the original generator speed and the filtered generator speed, and set the original cutoff frequency of the generator speed filter;

[0009] S3: Select multiple generator speeds, and compare any one of the generator speeds with the original generator speed. When the generator speed is equal to the original generator speed, the timer starts timing, and the detection cycle starts accumulating until the generator speed is equal to the filtered generator speed. After comparing the multiple generator speeds, multiple marked times are obtained;

[0010] S4: Set the delay threshold parameter and compare the time of multiple markers with the delay threshold parameter. When any of the time of multiple markers is less than the delay threshold parameter, the logic ends; when the time of multiple markers is greater than the delay threshold parameter at the same time, the generator speed filter cutoff frequency is scheduled.

[0011] Furthermore, the detection function flag bit confirmation in the S1 detection cycle is specifically as follows:

[0012] During the detection cycle, check whether the function flag Fenable is 1. If it is 1, the control function is turned on. If it is not 1, the logic ends.

[0013] Furthermore, collecting the original generator speed and the filtered generator speed in S2 specifically includes: collecting the original generator speed omega_o and the filtered generator speed omega_f.

[0014] Furthermore, the original cut-off frequency of the generator speed filter is set as follows:

[0015] The original generator speed omega_o is filtered, the low-frequency signal passes normally, and the high-frequency signal exceeding the set critical value is blocked and weakened; the set critical value is the cut-off frequency, and the original cut-off frequency of the generator speed filter is set to F1.

[0016] Furthermore, the S3 is specifically:

[0017] Select three generator speeds omega1, omega2, and omega3. When it is detected that the original generator speed omega_o is equal to omega1, timer T1 starts timing, and detection period T1 starts accumulating until the filtered generator speed omega_f is equal to omega1, and the timing ends and is marked as T2; when it is detected that the original generator speed omega_o is equal to omega2, timer T3 starts timing, and detection period T3 starts accumulating until the filtered generator speed omega_f is equal to omega2, and the timing ends and is marked as T4; when it is detected that the original generator speed omega_o is equal to omega3, timer T5 starts timing, and detection period T5 starts accumulating until the filtered generator speed omega_f is equal to omega3, and the timing ends and is marked as T6.

[0018] Furthermore, the delay threshold is set to T_threshold. When T2, T4 and T6 are simultaneously greater than T_threshold, the cutoff frequency is scheduled, and the original cutoff frequency F1 of the generator speed filter is set to F2.

[0019] Furthermore, when any one of T2, T4 or T6 is less than T_threshold, the logic ends.

[0020] Furthermore, the delay threshold T_threshold is set to 20-40ms.

[0021] Furthermore, when the generator set is a direct-drive set, omega1, omega2, and omega3 are set to 8 rpm, 10 rpm, and 12 rpm.

[0022] The present invention has at least the following beneficial effects:

[0023] 1. The present invention analyzes and determines the delay of the original generator speed and the generator speed after filtering, so as to schedule the cutoff frequency for filtering the original generator speed, thereby avoiding the problem of wind turbine control delay caused by excessive delay between the filtered generator speed participating in the control input and the actual generator speed.

[0024] 2. The present invention fully considers the influence of the delay of different generator speed input signals under different cut-off frequencies on the control effect of the unit by performing real-time comparison between the original generator speed and the generator speed after filtering, thereby completing the scheduling of different filter cut-off frequencies in real-time operation and effectively controlling the adverse effect of the delay of the generator speed input signal after filtering on the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] In the attached picture:

[0027] Figure 1 The present invention is a flow chart of a generator speed processing method for a wind turbine generator control system. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0029] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0030] like Figure 1 As shown, the present invention provides a generator speed processing method for a wind turbine generator control system, comprising:

[0031] S1: Confirmation of the detection function flag within the detection cycle;

[0032] In the current detection cycle, check whether the function flag Fenable is 1. If it is 1, it indicates that the control function is turned on. If it is not 1, the logic ends.

[0033] S2: Collect the original generator speed and the filtered generator speed, and set the original cutoff frequency of the generator speed filter;

[0034] Collect the original generator speed omega_o and the filtered generator speed omega_f. Since the original generator speed omega_o generally contains high-order frequency signals, but the wind turbine is a large rotating machine with large inertia, its control system does not need to respond to high-order frequency signals, so it is necessary to filter the original generator speed omega_o. The rule is that low-frequency signals can pass normally, while high-frequency signals exceeding the set critical value are blocked and weakened. This set critical value is the cutoff frequency, and the original cutoff frequency is set to F1. Due to the effect of low-pass filtering, the generator speed after filtering is delayed compared to the original generator speed.

[0035] S3: Select multiple generator speeds, and compare any one of the generator speeds with the original generator speed. When the generator speed is equal to the original generator speed, the timer starts timing, and each detection cycle starts accumulating until the generator speed is equal to the filtered generator speed. After comparing the multiple generator speeds, multiple marked times are obtained;

[0036] Select three generator speeds omega1, omega2, and omega3. For example, the direct-drive unit can be set to 8rpm, 10rpm, and 12rpm. When it is detected that the original generator speed omega_o is equal to omega1, timer T1 starts timing, and each detection cycle T1 starts to accumulate until the filtered generator speed omega_f is equal to omega1, and the timing ends and is marked as T2; when it is detected that the original generator speed omega_o is equal to omega2, timer T3 starts timing, and each detection cycle T3 starts to accumulate until the filtered generator speed omega_f is equal to omega2, and the timing ends and is marked as T4. When it is detected that the original generator speed omega_o is equal to omega3, timer T5 starts timing, and each detection cycle T5 starts to accumulate until the filtered generator speed omega_f is equal to omega3, and the timing ends and is marked as T6.

[0037] S4: Set the delay threshold parameter and compare the time of multiple markers with the delay threshold parameter. When any of the time of multiple markers is less than the delay threshold parameter, the logic ends; when the time of multiple markers is greater than the delay threshold parameter at the same time, the generator speed filter cutoff frequency is scheduled.

[0038] A delay threshold T_threshold is set, which can generally be set to 20-40ms. If T2, T4 and T6 are all greater than this delay threshold T_threshold, it means that the delay of the filtered generator speed will have an adverse effect on the control input of the wind turbine control system, and the cutoff frequency needs to be scheduled, and the original cutoff frequency F1 of the generator speed filter is set to F2.

[0039] If any one of T2, T4 and T6 is smaller than the delay threshold T_threshold, it means that the delay of the generator speed after filtering will not cause adverse effects on the control input of the wind turbine generator control system, and the logic ends.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for processing the generator speed of a wind turbine generator control system, characterized in that: include: S1: Confirmation of the detection function flag within the detection cycle; S2: Collect the original generator speed and the filtered generator speed, and set the original cutoff frequency of the generator speed filter; S3: Select multiple generator speeds, and compare any one of the generator speeds with the original generator speed. When the generator speed is equal to the original generator speed, the timer starts timing, and the detection cycle starts accumulating until the generator speed is equal to the filtered generator speed. After comparing the multiple generator speeds, multiple marked times are obtained; S4: Set the delay threshold parameter and compare the time of multiple markers with the delay threshold parameter. When any of the time of multiple markers is less than the delay threshold parameter, the logic ends; when the time of multiple markers is greater than the delay threshold parameter at the same time, the generator speed filter cutoff frequency is scheduled; The detection function flag bit confirmation in the S1 detection cycle is specifically as follows: During the detection cycle, check whether the function flag Fenable is 1. If it is 1, the control function is turned on. If it is not 1, the logic ends. The original cut-off frequency of the generator speed filter is set as follows: The original generator speed omega_o is filtered, the low-frequency signal passes normally, and the high-frequency signal exceeding the set critical value is blocked and weakened; the set critical value is the cut-off frequency, and the original cut-off frequency of the generator speed filter is set to F1.

2. A generator speed processing method for a wind turbine generator control system according to claim 1, characterized in that: The S3 is specifically: Select three generator speeds omega1, omega2, and omega3. When it is detected that the original generator speed omega_o is equal to omega1, timer T1 starts timing, and detection period T1 starts accumulating until the filtered generator speed omega_f is equal to omega1, and the timing ends and is marked as T2; when it is detected that the original generator speed omega_o is equal to omega2, timer T3 starts timing, and detection period T3 starts accumulating until the filtered generator speed omega_f is equal to omega2, and the timing ends and is marked as T4; when it is detected that the original generator speed omega_o is equal to omega3, timer T5 starts timing, and detection period T5 starts accumulating until the filtered generator speed omega_f is equal to omega3, and the timing ends and is marked as T6.

3. The method for processing the generator speed of a wind turbine generator control system according to claim 1, characterized in that: The delay threshold is set to T_threshold. When T2, T4 and T6 are simultaneously greater than T_threshold, the cutoff frequency is scheduled, and the original cutoff frequency F1 of the generator speed filter is set to F2.

4. A generator speed processing method for a wind turbine generator control system according to claim 3, characterized in that: When any one of T2, T4 or T6 is less than T_threshold, the logic ends.

5. The method for processing the generator speed of a wind turbine generator control system according to claim 3, characterized in that: The delay threshold T_threshold is set to 20-40ms.

6. The method for processing the generator speed of a wind turbine generator control system according to claim 3, characterized in that: When the generator set is a direct-drive set, omega1, omega2, and omega3 are set to 8 rpm, 10 rpm, and 12 rpm.

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