An adaptive pitch control method for stabilizing wind turbine speed

Abstract

The present invention discloses an adaptive variable pitch control method for stabilizing the speed of a wind turbine generator set, comprising the following steps: S1, judging the rated speed setting of the wind turbine generator set according to the power limit instruction of the wind turbine generator set, the optimal gain value of the torque control designed for the wind turbine generator set, and the lower limit speed of the resonance range and the upper limit speed of the resonance range of the wind turbine generator set; S2, limiting the change rate of the power limit instruction of the wind turbine generator set; S3, calculating the torque given of the actual wind turbine generator set; S4, calculating the speed given according to the limited change rate and the torque given; S5, setting the variable pitch control parameters; S6, judging the conditions of the wind turbine generator set, selecting the corresponding variable pitch control parameters for control, thereby stabilizing the speed of the wind turbine generator set; S7, performing simulation verification; the present invention can improve the response of the variable pitch system of the wind turbine generator set to external wind speed changes, play a role in stabilizing the speed, prevent the speed of the wind turbine generator set from entering the resonance zone, and reduce the possibility of vibration failure under wake conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of adaptive pitch control of wind turbines, and in particular to an adaptive pitch control method for stabilizing the rotational speed of a wind turbine under power-limited operation conditions. Background Art

[0002] When air flows through the swept plane of a wind turbine's rotor, the blades absorb some of the wind energy, blocking and separating the airflow. This significantly reduces wind speed and increases turbulence downwind of the turbine, a phenomenon known as the turbine wake effect. With the development of large-scale wind farms, offshore wind turbines are becoming larger, making them more significantly affected by wakes. The combined effect of turbine wakes between turbines and within wind farms is particularly pronounced.

[0003] Vibration failures of the unit often occur under power-limited conditions in wake conditions, especially when the unit's operating speed is at the lower limit of the resonance range due to power and electricity restrictions. At this time, the torque is likely to reach saturation, so the speed control is mainly completed by the pitch system. However, the pitch response speed cannot respond quickly to changes in external wind conditions according to conventional designs, causing the unit's operating speed to enter the resonance range. Especially under wake conditions, the influence of the wake and the resonance often make vibration failures more likely to occur. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies in the prior art and provide an adaptive pitch control method for stabilizing the speed of a wind turbine. An adaptive pitch control is designed to optimize the speed of the turbine under wake conditions, where the turbine operating speed is at the lower limit of the resonance range due to power restrictions. At this time, the response of the pitch system is improved to the external wind speed changes by accelerating the response of the pitch system, thereby stabilizing the speed.

[0005] The object of the present invention is achieved through the following technical solution: An adaptive pitch control method for stabilizing the speed of a wind turbine generator system comprises the following steps:

[0006] S1. According to the wind turbine generator's power limit instruction A, the wind turbine generator's designed torque control optimal gain value B, and the wind turbine generator's resonance range lower limit speed and resonance range upper limit speed, determine whether the wind turbine generator's rated speed is set to the resonance range lower limit speed or the design speed;

[0007] S2. Limit the change rate of the power limit instruction A of the wind turbine generator to obtain a change rate limit instruction A';

[0008] S3. Calculate the actual wind turbine torque reference C, i.e., the maximum torque constraint that the wind turbine can output, based on the rate-of-change limit instruction A', the optimal torque control gain value B, the rated speed, and the grid-connected speed;

[0009] S4. Calculate the speed reference D = A' / C according to the limited rate-of-change command A' and the torque reference C, i.e., the reference speed for pitch control.

[0010] S5. According to steps S1 to S4, tune the control parameters of the pitch controller for the wind turbine under normal operation conditions without power limitation and under power limitation conditions, and calculate the pitch control parameters that do not exhibit step changes.

[0011] S6. Based on the blade angle, generator speed, lower bound speed of the resonance range, and upper bound speed of the resonance range of the wind turbine, determine the conditions of the wind turbine and select the corresponding pitch control parameters for control to stabilize the speed of the wind turbine.

[0012] S7. Conduct simulation verification to evaluate the operating characteristics of the wind turbine during the response to power limitation under power curtailment conditions.

[0013] Furthermore, step S1 includes the following steps:

[0014] Judge whether A > B * (lower bound speed of the resonance range) 3 and A < B * (upper bound speed of the resonance range) 3 . If satisfied, set the rated speed of the wind turbine to the lower bound speed of the resonance range; if not satisfied, set the rated speed of the wind turbine to the design speed.

[0015] Furthermore, step S3 includes the following steps:

[0016] S301. Judge whether the limited rate-of-change command A' > B * (rated speed) 3 at this time: If satisfied, calculate the torque reference C = A' / rated speed and enter step S4; if not satisfied, enter step S302;

[0017] S302. Judge whether the limited rate-of-change command A' < B * (grid-connected speed) 3 at this time: If satisfied, calculate the torque reference C = A' / grid-connected speed and enter step S4; if not satisfied, enter step S303;

[0018] S303. Calculate the torque reference and enter step S4.

[0019] Furthermore, in step S5, the tuning of the control parameters of the pitch controller for the wind turbine under power limitation conditions includes the following steps:

[0020] First, calculate the optimal operating power P1 corresponding to the lower bound of the resonance range of the wind turbine and the optimal operating power P2 corresponding to the upper bound of the resonance range. When the power limitation command A is in the range of P1 < A < P2, set the speed reference of the wind turbine to the lower bound speed of the resonance range.

[0021] Adjust the wind turbine model parameters, set the rated power of the wind turbine model to the power limit value A, calculate the rated speed and rated torque based on the rated power and the optimal gain value, and then adjust the corresponding design parameters in the wind turbine model;

[0022] Finally, the adjusted wind turbine model is linearized and the parameters of the pitch controller are tuned.

[0023] Furthermore, in step S5, the calculation of the pitch control parameter without step change includes the following steps:

[0024]

[0025] Among them, E1 is the pitch control parameter of the wind turbine under normal operating conditions without power restriction, E2 is the pitch control parameter of the wind turbine under power restriction conditions, and E3 is the pitch control parameter without step change.

[0026] Further, step S6 includes the following steps:

[0027] S601, obtaining blade angles, pitch control parameters of the wind turbine generator set under normal operation without power restriction, and pitch control parameters of the wind turbine generator set under power restriction;

[0028] S602: Determine whether the generator speed is greater than the upper limit speed of the resonance range. If so, select the variable pitch control parameters of the wind turbine under normal operation without power restriction for control. If not, proceed to step S603.

[0029] S603, determining whether the generator speed is not greater than the lower limit speed of the resonance range; if so, selecting the variable pitch control parameters of the wind turbine under power-limiting conditions for control; if not, selecting the variable pitch control parameters without step changes for control.

[0030] The present invention provides a non-transitory computer-readable medium storing instructions. When the instructions are executed by a processor, the steps of the above-mentioned adaptive pitch control method for stabilizing the speed of a wind turbine are performed.

[0031] The present invention provides a computing device comprising a processor and a memory for storing a program executable by the processor. When the processor executes the program stored in the memory, the above-mentioned adaptive pitch control method for stabilizing the speed of a wind turbine is implemented.

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

[0033] The present invention optimizes the wind turbine's operating speed under wake conditions due to power restrictions, accelerates the response of the pitch control system, and improves the response of the wind turbine's pitch control system to external wind speed changes, thereby stabilizing the speed and preventing the wind turbine's speed from entering the resonance zone, thereby reducing the possibility of vibration failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the control logic block diagram for outputting the reference speed for pitch control.

[0035] Figure 2 The logic block diagram for calculating the pitch control parameters of a wind turbine. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to specific embodiments.

[0037] Example 1

[0038] See also Figures 1 to 2 As shown in FIG, the adaptive pitch control method for stabilizing the speed of a wind turbine provided in this embodiment includes the following steps:

[0039] S1, according to the wind turbine generator's power limit instruction A, the wind turbine generator's designed torque control optimal gain value B, and the wind turbine generator's resonance interval lower limit speed and resonance interval upper limit speed, determining whether the wind turbine generator's rated speed is set to the resonance interval lower limit speed or the design speed, including the following steps:

[0040] Determine whether A>B*(lower limit speed of resonance range) is satisfied 3 And A<B*(the upper limit speed of the resonance range) 3 If the condition is satisfied, the rated speed of the wind turbine is set to the lower limit speed of the resonance range. If the condition is not satisfied, the rated speed of the wind turbine is set to the design speed.

[0041] S2. Limit the change rate of the power limit instruction A of the wind turbine generator to obtain a change rate limit instruction A';

[0042] S3, calculating the actual wind turbine torque reference C, i.e., the maximum torque constraint that the wind turbine can output, based on the rate-of-change limit instruction A', the torque control optimal gain value B, the rated speed, and the grid-connected speed, including the following steps:

[0043] S301, determine whether the limit change rate instruction A'>B*(rated speed) is satisfied at this time 3 If the condition is satisfied, the torque reference C=A' / rated speed is calculated and the process goes to step S4; if not, the process goes to step S302;

[0044] S302. Determine whether the current situation satisfies the limited change rate instruction A' < B * (grid-connected speed). 3 : If it is satisfied, calculate the torque command C = A' / grid-connected speed, and proceed to step S4; if not, proceed to step S303;

[0045] S303. Calculate the torque command Proceed to step S4.

[0046] S4. Calculate the speed command D = A' / C according to the limited change rate instruction A' and the torque command C, that is, the reference speed for pitch control;

[0047] S5. According to steps S1 to S4, perform control parameter tuning for the pitch controller of the wind turbine under non-limited power normal operation conditions and under limited power conditions, and at the same time calculate the pitch control parameters that do not undergo step changes, including the following steps:

[0048] Perform pitch control parameter tuning for the pitch controller of the wind turbine under non-limited power normal operation conditions according to the well-known method to obtain the pitch control parameter E1, as shown in Table A below:

[0049] Pitch angle rad kp ki 0.05463 0.07296 0.0072 0.1213 0.053274 0.005335 0.1703 0.044091 0.00417 0.2321 0.035206 0.004328 0.2873 0.029013 0.00493 0.3379 0.025882 0.004561

[0050] Table A Pitch control parameter E1 of the wind turbine under non-power-limited normal operation conditions

[0051] Perform pitch control parameter tuning for the pitch controller of the wind turbine under limited power conditions, including the following steps:

[0052] First, calculate the optimal operating power P1 corresponding to the lower bound of the resonance interval of the wind turbine and the optimal operating power P2 corresponding to the upper bound of the resonance interval. When the limited power instruction A is in the range of P1 < A < P2, the speed command of the wind turbine is set to the lower bound speed of the resonance interval; in this embodiment, that is, when P1 = 404 kW and P-2 = 1188 kW, the controller parameters can be tuned according to the condition of the limited power A = 1000 kW.

[0053] Adjust the model parameters of the wind turbine, set the limited power value of 1000 kW as the rated power of the wind turbine model, calculate the rated speed and rated torque according to this rated power and the optimal gain value, and then adjust the corresponding design parameters in the wind turbine model;

[0054] Finally, linearize the adjusted wind turbine model and perform parameter tuning of the pitch controller to obtain the pitch control parameter E2, as shown in Table B below:

[0055] Pitch angle rad kp ki 0.045424 0.342912 0.01656 0.156067 0.20758 0.00817 0.261757 0.13417 0.00578 0.376883 0.10109 0.00491 0.500224 0.08133 0.00445 0.606985 0.06909 0.00418

[0056] Table B Pitch control parameter E2 of the wind turbine under power-limited conditions

[0057] The formula for calculating the pitch control parameters without step changes is as follows:

[0058]

[0059] Among them, E1 is the pitch control parameter of the wind turbine under normal operating conditions without power restriction, E2 is the pitch control parameter of the wind turbine under power restriction conditions, and E3 is the pitch control parameter without step change.

[0060] S6, judging the conditions of the wind turbine according to the blade angle of the wind turbine, the generator speed, the lower limit speed of the resonance range, and the upper limit speed of the resonance range, and selecting corresponding variable pitch control parameters for control, thereby stabilizing the speed of the wind turbine, including the following steps:

[0061] S601, obtaining blade angles, pitch control parameters of the wind turbine generator set under normal operation without power restriction, and pitch control parameters of the wind turbine generator set under power restriction;

[0062] S602: Determine whether the generator speed is greater than the upper limit speed of the resonance range. If so, select the variable pitch control parameters of the wind turbine under normal operation without power restriction for control. If not, proceed to step S603.

[0063] S603, determining whether the generator speed is not greater than the lower limit speed of the resonance range; if so, selecting the variable pitch control parameters of the wind turbine under power-limiting conditions for control; if not, selecting the variable pitch control parameters without step changes for control.

[0064] S7. Perform simulation verification to evaluate the operating characteristics of the wind turbine in response to power limitation under power limitation conditions, including the following steps:

[0065] S701, write controller code;

[0066] S702. Test and verify the normal non-restricted wind turbine model, with the simulated wind speed set above the rated wind speed, and use an external controller to adjust the rated power to a limited power of 1000 kW, and then restore the rated power operation;

[0067] S703. Evaluate the wind turbine's operating characteristics such as speed, vibration, and power during the wind turbine's response to power limitation.

[0068] Example 2

[0069] This embodiment discloses a non-transitory computer-readable medium storing instructions. When the instructions are executed by a processor, the steps of the adaptive pitch control method for stabilizing the speed of a wind turbine generator set according to embodiment 1 are performed.

[0070] The non-transitory computer-readable medium in this embodiment can be a 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 other media.

[0071] Example 3

[0072] 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 adaptive pitch control method for stabilizing the speed of a wind turbine generator described in Example 1 is implemented.

[0073] 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.

[0074] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any changes made based on the shape and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. An adaptive pitch control method for stabilizing the speed of a wind turbine, characterized in that: It includes the following steps: S1. According to the power limit instruction A of the wind turbine, the optimal gain value B of the torque control designed for the wind turbine, and the lower bound speed and upper bound speed of the resonance interval of the wind turbine, determine whether the rated speed of the wind turbine is set as the lower bound speed of the resonance interval or the designed speed, including the following steps: Determine whether it is satisfied and If the condition is satisfied, the rated speed of the wind turbine is set to the lower limit speed of the resonance range; if the condition is not satisfied, the rated speed of the wind turbine is set to the design speed; S2. Limit the change rate of the power limit instruction A of the wind turbine generator to obtain the change rate limit instruction ; S3, according to the limited change rate instruction , the torque control optimal gain value B, the rated speed and the grid-connected speed, and calculate the actual wind turbine torque reference C, that is, the maximum torque constraint that the wind turbine can output, including the following steps: S301, determine whether the limit change rate instruction is met at this time :If satisfied, calculate the torque given , go to step S4; if not, go to step S302; S302: Determine whether the rate-of-change limit instruction is satisfied at this time. :If satisfied, calculate the torque given , go to step S4; if not, go to step S303; S303, calculate torque setting , proceed to step S4; S4, according to the limited change rate instruction Calculate the speed setting by adding the torque setting C , which is the reference speed for pitch control; S5. According to steps S1 to S4, perform control parameter tuning on the pitch controller of the wind turbine under non-power-limit normal operation conditions and under power-limit conditions, and at the same time calculate the pitch control parameters that do not undergo step changes; The step of performing control parameter tuning on the pitch controller of the wind turbine under power-limit conditions includes the following steps: First, calculate the optimal operating power P1 corresponding to the lower bound of the resonance interval of the wind turbine and the optimal operating power P2 corresponding to the upper bound of the resonance interval. When the power limit instruction A satisfies P1 < A < P2, the speed setpoint of the wind turbine is set as the lower bound speed of the resonance interval; Adjust the model parameters of the wind turbine, set the rated power of the wind turbine model as the power limit value A, calculate the rated speed and rated torque based on this rated power and the optimal gain value, and then adjust the corresponding design parameters in the wind turbine model; Finally, linearize the adjusted wind turbine model and perform parameter tuning of the pitch controller; S6. According to the blade angle, generator speed, lower bound speed and upper bound speed of the resonance interval of the wind turbine, judge the conditions of the wind turbine, and select the corresponding pitch control parameters for control to stabilize the speed of the wind turbine; S7. Conduct simulation verification to evaluate the operating characteristics of the wind turbine during the response to the power limit process under power curtailment conditions.

2. The adaptive pitch control method for stabilizing the speed of a wind turbine according to claim 1, characterized in that: In step S5, the calculation of the pitch control parameters that do not undergo step changes includes the following steps: ； Among them, E1 is the pitch control parameter of the wind turbine under non-power-curtailment normal operation conditions, E2 is the pitch control parameter of the wind turbine under power-curtailment conditions, and E3 is the pitch control parameter that does not undergo step changes.

3. The adaptive pitch control method for stabilizing the speed of a wind turbine according to claim 1, characterized in that: The step S6 includes the following steps: S601. Obtain the blade angle, the pitch control parameter of the wind turbine under non-power-curtailment normal operation conditions, and the pitch control parameter of the wind turbine under power-curtailment conditions; S602. Judge whether it satisfies that the generator speed is greater than the upper bound speed of the resonance interval. If it is satisfied, select the pitch control parameter of the wind turbine under non-power-curtailment normal operation conditions for control. If it is not satisfied, go to step S603; S603. Judge whether it satisfies that the generator speed is not greater than the lower bound speed of the resonance interval. If it is satisfied, select the pitch control parameter of the wind turbine under power-curtailment conditions for control. If it is not satisfied, select the pitch control parameter that does not undergo step changes for control.

4. A non-transitory computer-readable medium storing instructions, characterized in that: When the instruction is executed by the processor, execute the steps of the adaptive pitch control method for stabilizing the speed of the wind turbine according to any one of claims 1 to 3.

5. 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, implement the adaptive pitch control method for stabilizing the speed of the wind turbine according to any one of claims 1 to 3.

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