An optimal power generation coordinated control system for wind farms

Abstract

This invention pertains to wind turbine control systems, specifically an optimal power generation and coordination control system for wind farms. The system includes a wind speed detection unit, a rotational speed detection unit, a pitch angle detection unit, an operating status detection unit, a turbine controller, a pitch actuator, a bidirectional converter, and a generator. When the turbine is in the power supply boundary zone and wind speed increases, the turbine controller controls the pitch actuator to briefly increase the pitch. Based on the pitch angle change and the turbine rotational speed decrease slope, a pre-pitch increase response is determined. Then, based on the pre-pitch increase response and the difference between the rotational speed and the power supply start-up threshold, the pre-pitch increase target angle and duration are adjusted. Once the rotational speed falls below the power supply start-up threshold, the bidirectional converter is triggered to supply power, causing the generator to output torque booster. Subsequently, based on the pre-pitch increase response, the torque booster and pitch recovery rate are adjusted so that the torque booster and aerodynamic torque jointly propel the turbine past the power supply stability threshold, thereby reducing repeated switching in the boundary zone.

Description

Technical Field

[0001] This invention pertains to wind turbine control systems, specifically an optimal power generation coordination control system for wind farms. Background Technology

[0002] When wind turbines operate at low wind speeds or face starting difficulties, power is typically supplied from the grid via a bidirectional converter, allowing the generator to operate in electric mode briefly. This drives the rotor to accelerate to near the cut-in speed. Once the cut-in conditions are met, the electric boost is stopped, and the rotor is driven by the torque generated by the wind on the blades, putting the generator into operation. Simultaneously, the turbine can adjust the blade angle via the pitch system to control the rotor speed and energy capture level.

[0003] While it can assist the unit in establishing speed at low speeds and intervene in the rotor state through pitch adjustment, possessing a certain degree of cut-in control capability, when the unit is in the deceleration process and approaches the boundary zone of cutting in or out of power generation, the wind-side driving force, power generation load, and state switching criteria often fluctuate simultaneously. This makes the rotor speed prone to repeatedly exceeding the boundary, resulting in frequent switching between power generation and non-power generation states. This not only causes operational instability but also increases the number of control switching operations and makes the wind-side and electrical-side connection processes less smooth. Summary of the Invention

[0004] The purpose of this invention is to provide an optimal power generation and coordinated control system for wind farms, including a wind speed detection unit, a rotational speed detection unit, a pitch angle detection unit, an operating status detection unit, a unit controller, a pitch actuator, a bidirectional converter, and a generator; The unit controller is connected to the wind speed detection unit, the speed detection unit, the pitch angle detection unit, the operating status detection unit, the pitch actuator, and the bidirectional converter, respectively. The unit controller is configured as follows: When the unit speed is higher than the power supply start-up threshold and the power supply stabilization condition has not yet been met, the unit is determined to be in the power supply boundary zone operating condition. When the unit is in the power supply boundary zone and the wind speed is increasing, the pitch actuator is controlled to increase the pitch during the pre-pitch increase duration. During the pitch increase process, the pre-pitch increase response amount is determined based on the pitch angle change data and the unit speed decrease data; Based on the pre-steering response and the remaining speed difference between the current unit speed and the power supply start-up threshold, adjust the pre-steering target angle or the pre-steering duration to bring the unit speed back below the power supply start-up threshold. After the unit speed drops below the power supply start-up threshold, the bidirectional converter is controlled to enter the power supply mode, so that the generator outputs auxiliary torque. After the power supply mode is established, the torque booster set value and pitch recovery rate are determined according to the pre-increase pitch response amount, and the pitch actuator is controlled to restore the pitch according to the pitch recovery rate, so that the torque booster and the aerodynamic torque generated by the restored pitch jointly drive the unit speed to rise above the de-power supply stability threshold. After the unit meets the exit conditions, the bidirectional converter is controlled to exit the power supply mode; in case of abnormal operating conditions, rollback control is executed.

[0005] Furthermore, the unit controller is configured to: when the unit speed is higher than the power supply start-up threshold and lower than the power supply de-stabilization threshold, determine the range of unit speed as a candidate boundary zone; within the candidate boundary zone, determine that the unit is in the power supply boundary zone operating condition based on at least two of the following: the speed fluctuation amplitude, the number of mode switching, and the bidirectional converter power supply status within a preset time window.

[0006] Furthermore, the unit controller is configured to calculate the slope of wind speed change, the change in the moving average, or the slope of linear fitting based on the wind speed detection values ​​at multiple consecutive sampling times, and to determine that the wind speed is in an upward trend when the calculation result is greater than the wind speed rise threshold.

[0007] Furthermore, the pre-pitch increase response is used to characterize the degree of decrease in unit speed corresponding to a unit pitch angle change; the unit controller is configured to determine the pre-pitch increase response based on the ratio of the decrease in unit speed to the change in pitch angle, or to determine the pre-pitch increase response based on the ratio of the slope of the decrease in unit speed to the rate of change in pitch angle.

[0008] Further, the remaining speed difference is the difference between the current speed of the unit and the power supply start-up threshold; the unit controller is configured to: shorten the pre-pitch increase duration or decrease the pre-pitch increase target angle when the pre-pitch increase response amount is greater than the first response threshold and the remaining speed difference is less than the preset difference; and extend the pre-pitch increase duration or increase the pre-pitch increase target angle when the pre-pitch increase response amount is less than the second response threshold and the current speed of the unit is still higher than the power supply start-up threshold; wherein, the first response threshold is greater than the second response threshold.

[0009] Furthermore, the unit controller is configured to control the bidirectional converter to provide driving power to the generator after the unit speed drops below the power supply start-up threshold, so that the generator outputs the auxiliary torque; and to determine whether the power supply mode is successfully established based on at least one of the bidirectional converter mode feedback, generator current establishment status, auxiliary torque establishment time, and torque feedback signal.

[0010] Furthermore, the unit controller is configured to: reduce the torque booster setting value or reduce the pitch recovery rate when the pre-pitch booster response value is greater than a third response threshold; increase the torque booster setting value or extend the power supply duration and reduce the pitch recovery rate when the pre-pitch booster response value is less than a fourth response threshold; wherein the third response threshold is greater than the fourth response threshold; the unit controller is also configured to control the pitch actuator to start recovering the pitch after the torque booster reaches a preset establishment ratio.

[0011] Furthermore, the exit conditions include: the unit speed continuously exceeding the power supply disconnection stability threshold for a stable confirmation period; the unit speed fluctuation amplitude not exceeding a preset fluctuation threshold; the bidirectional converter switching state being stable; and the unit output power meeting the grid connection power generation requirements.

[0012] Furthermore, the operating status detection unit is used to detect the power supply status of the bidirectional converter, the power generation status of the unit, the number of mode switching times within a preset time window, the speed fluctuation amplitude, the power supply establishment status, and the generator torque assist establishment status.

[0013] Furthermore, the abnormal operating conditions include at least one of the following: the wind speed rise trend is lower than the wind speed rise threshold, the unit speed does not reach the preset acceleration requirement after the power supply mode is established, the pre-pitch increase response exceeds the allowable response range, the power supply mode is not established within the preset establishment time, and the unit speed oscillation amplitude is greater than the oscillation threshold; the backoff control includes at least one of the following: stopping the pre-pitch increase control, limiting the pitch recovery rate, extending the power supply duration, adjusting the torque booster, re-executing the pre-pitch increase control, re-triggering the power supply mode, or switching the unit to a conservative operating state; the conservative operating state is an operating state that limits the pitch change rate and limits the upper limit of the torque booster.

[0014] The beneficial effects achieved by the present invention using the above solution are as follows: This invention, when the generator is in the power supply boundary zone and the wind speed is increasing, first controls the pitch angle to increase briefly, so that the generator speed drops back to below the power supply start-up threshold, and then re-triggers power supply and restores the pitch. This allows the generator's torque-assisted torque and the aerodynamic torque after the pitch is restored to work together on the generator, thereby enabling the generator to cross the power supply boundary more stably and improving the cross-boundary stability during the low wind speed transition phase.

[0015] This invention observes the decrease in rotational speed after pitch change during pre-pitch increment in real time, and obtains the pre-pitch response quantity from this. This allows for determination of the unit's sensitivity to the pre-pitch action, thus avoiding situations where the pre-pitch increment is too small, preventing power supply from being triggered, or too large, causing excessive speed drop. Attached Figure Description

[0016] Figure 1 This is a system structure diagram of the optimal power generation and coordinated control system for wind farms according to the present invention.

[0017] Figure 2 This is a flowchart of the control method for the optimal power generation collaborative control system of a wind farm according to the present invention.

[0018] Figure 3 This is a schematic diagram of the action chain of the optimal power generation collaborative control system for wind farms of the present invention. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] In this embodiment, an optimal power generation coordination control system for wind farms is applied to wind turbine generators, which is particularly suitable for the boundary zone conditions where the generator is transitioning from a low wind speed to a power generation state and the generator speed is close to the power supply start-up threshold and the power supply stabilization threshold.

[0021] like Figure 1 As shown, the control system in this embodiment includes a wind speed detection unit, a rotational speed detection unit, a pitch angle detection unit, an operating status detection unit, a unit controller, a pitch actuator, a bidirectional converter, and a generator.

[0022] The wind speed detection unit is used to collect the current wind speed data of the unit. The wind speed detection unit can be a wind speed sensor installed outside the nacelle, or it can be an equivalent incoming wind speed acquisition structure that works in conjunction with the unit's state estimation model. The wind speed detection unit sends the collected wind speed signal to the unit controller.

[0023] The speed detection unit is used to detect the unit's speed. The speed detection unit can employ an encoder or speed sensor mounted on the main shaft or generator shaft end, or it can use a speed detection structure derived from the generator's electrical parameters. The speed detection unit sends the real-time unit speed to the unit controller.

[0024] The pitch angle detection unit is used to detect the current pitch angle of the blade. The pitch angle detection unit is set in the pitch drive link of each blade and is used to feed back the current pitch angle, pitch change, and pitch change rate of the blade to the unit controller.

[0025] The operation status detection unit is used to detect the unit's operating mode and switching status. Specifically, the operation status detection unit is used to detect whether the bidirectional converter is currently in power supply mode, power generation mode, or standby mode. It is also used to detect the number of mode switching times, speed fluctuation amplitude, power supply establishment status, and generator torque boosting torque establishment status within a preset time window, so that the unit controller can determine whether the unit has a risk of boundary oscillation.

[0026] The pitch actuator is connected to the blades and is used to execute pitch adjustment commands output by the unit controller. The pitch actuator can be an electric pitch actuator or a hydraulic pitch actuator.

[0027] The bidirectional converter is electrically connected to the generator and to the grid side, and is used to switch between power supply mode and power generation mode under the control of the unit controller. When the bidirectional converter enters power supply mode, the grid-side electrical energy is delivered to the generator through the bidirectional converter, enabling the generator to output auxiliary torque; when the bidirectional converter exits power supply mode and enters power generation mode, the electrical energy output by the generator is fed into the grid through the bidirectional converter.

[0028] A generator is used to output torque in power supply mode and electrical energy in stable power generation mode. The generator can be a permanent magnet synchronous generator, a doubly-fed generator, or other generators suitable for bidirectional energy exchange.

[0029] The unit controller is the core control unit of this system. The unit controller can consist of a processor, memory, and input / output interfaces. The memory stores the control program, and after the processor executes the control program, it forms the following modules: boundary zone identification module, wind speed trend judgment module, pre-pitch control module, pre-pitch response detection module, deceleration depth adjustment module, power supply trigger control module, torque boost and pitch recovery coordination module, stable power supply determination module, and protection backoff module.

[0030] The boundary zone identification module is used to identify whether the unit is in the power supply boundary zone based on the speed detection signal and the operating status detection signal.

[0031] The operating condition of the energy supply boundary zone is as follows: the unit speed is higher than the energy supply start-up threshold, but has not yet stably crossed the de-supply stability threshold, and the unit still has the risk of falling back to the energy supply zone.

[0032] Preferably, the boundary zone identification module identifies the interval between the unit speed and the de-energization stability threshold as a candidate boundary zone, and further confirms whether the unit belongs to the boundary oscillation risk condition by combining the recent mode switching frequency, speed fluctuation amplitude or bidirectional converter power supply status.

[0033] The wind speed trend judgment module is used to determine whether the wind speed is in an upward trend based on the wind speed data obtained from continuous sampling. Preferably, the wind speed trend judgment module makes the judgment based on the slope of wind speed change, the change of moving average, or the result of linear fitting at multiple consecutive sampling times; when the judgment result is greater than a preset trend threshold, the wind speed is determined to be in an upward trend.

[0034] The pre-pitch increase control module is used to control the pitch actuator to briefly increase the pitch when the unit is operating in the power supply boundary zone and the wind speed is increasing. Because the increased pitch changes the windward force on the blades, the aerodynamic torque of the blades decreases, thereby causing the unit speed to drop. The control objective of the pre-pitch increase control module is to bring the unit speed back below the power supply start-up threshold to re-meet the power supply triggering conditions.

[0035] The pre-pitch increase response detection module is used to acquire the pitch angle change and the unit speed change during the short-term pitch increase controlled by the pre-pitch increase control module's pitch actuator. Based on the pitch angle change and the unit speed decrease slope, the pre-pitch increase response is determined. This pre-pitch increase response characterizes the unit's sensitivity to speed drop-off during pre-pitch increase operations under current power supply boundary conditions.

[0036] The speed reduction depth adjustment module is used to adjust the pre-pitch target angle and / or pre-pitch duration based on the pre-pitch response amount, the remaining difference between the current unit speed and the power supply start-up threshold, so that the unit speed drops back below the power supply start-up threshold. Specifically, when the pre-pitch response amount is greater than the preset response threshold, the speed reduction depth adjustment module ends the pre-pitch control early or reduces the pre-pitch target angle; when the pre-pitch response amount is less than the preset response threshold, the speed reduction depth adjustment module extends the pre-pitch duration or increases the pre-pitch target angle.

[0037] With the above settings, the pre-pitch increment process is no longer executed only according to a fixed pitch increment and a fixed duration. Instead, it is adjusted according to the actual speed drop response of the unit in the current boundary zone, so that the unit speed drops back to below the power supply start-up threshold with a small kinetic energy loss, avoiding insufficient or excessive pre-pitch increment.

[0038] The power supply trigger control module is used to send a power supply switching command to the bidirectional converter after the unit speed drops below the power supply start threshold, so that the bidirectional converter enters the power supply mode and the generator outputs auxiliary torque.

[0039] The power supply trigger control module can also determine whether the power supply has been successfully established based on the bidirectional converter mode feedback, generator current establishment status, torque boosting torque establishment time, or torque feedback signal.

[0040] The torque assist and pitch recovery coordination module is used to adjust the generator torque assist and / or pitch recovery rate based on the pre-pitch increase response after the bidirectional converter enters power supply mode. Specifically, when the pre-pitch increase response indicates that the unit speed is decreasing rapidly, the torque assist and pitch recovery coordination module reduces the torque assist or slows down the pitch recovery rate; when the pre-pitch increase response indicates that the unit speed is decreasing slowly, the torque assist and pitch recovery coordination module increases the torque assist or extends the duration of the torque assist, so that the torque assist and the aerodynamic torque after pitch recovery jointly drive the unit to pass the de-power supply stability threshold.

[0041] The torque assist and pitch recovery coordination module is also used to determine the timing of pitch recovery based on the power supply establishment status. Preferably, when the bidirectional converter enters the power supply mode and the generator torque assist reaches the preset establishment ratio, the torque assist and pitch recovery coordination module controls the pitch actuator to start recovering the pitch; when the torque assist establishment speed is lower than the preset establishment speed, the pitch recovery is delayed or the pitch recovery rate is reduced; when the torque assist establishment fails, the pitch recovery is stopped and protection backoff control is entered.

[0042] The stable power supply disconnection determination module is used to determine whether the unit has exceeded the stable power supply disconnection threshold. Preferably, the stable power supply disconnection determination module makes a determination based on at least two of the following conditions: the unit speed is continuously higher than the stable power supply disconnection threshold for a preset duration; the unit speed fluctuation amplitude is not greater than a preset fluctuation threshold; the bidirectional converter switching state is stable; and the unit output power meets the grid connection power generation requirements. When the exit conditions are met, the stable power supply disconnection determination module controls the bidirectional converter to exit the power supply mode, allowing the unit to enter a stable power generation state.

[0043] The protection backoff module is used to perform backoff control under abnormal conditions. Abnormal conditions include wind speed trend failure, unit acceleration failure, abnormal pre-pitch response, power supply establishment failure, and abnormal boundary oscillation.

[0044] Specifically, when the wind speed rise trend disappears, the unit does not exceed the de-energization stability threshold within a preset time period, the pre-pitch boost response exceeds the safety response threshold, the energization establishment status is abnormal, or the number of energization and de-energization switching times exceeds the threshold within a preset time window, the protection backoff module can perform at least one of the following measures: limit the pitch recovery speed, end the pre-pitch boost control in advance, extend the energization mode duration, increase or decrease the torque boost, re-execute the pre-pitch boost control, re-trigger the energization mode, or keep the unit in a conservative operating state to avoid the unit being in an unstable state of frequent switching.

[0045] In this embodiment, the wind speed detection unit, speed detection unit, pitch angle detection unit, and operating status detection unit constitute the status input layer; the functional modules in the unit controller constitute the decision layer; and the pitch actuator, bidirectional converter, and generator constitute the execution layer. The status input layer feeds back the unit status to the decision layer in real time. The decision layer generates pitch control commands and power supply switching commands and sends them to the execution layer, thus forming a closed-loop control structure.

[0046] Based on the above system structure, such as Figure 2 As shown, the control logic in this embodiment is executed by the unit controller, and specifically includes the following process.

[0047] First, the unit controller periodically receives the wind speed signal output by the wind speed detection unit, the speed signal output by the speed detection unit, the pitch angle signal output by the pitch angle detection unit, and the operating status signal output by the operating status detection unit, and performs filtering and synchronization processing on each detection signal to obtain the effective status quantity within the current control cycle.

[0048] Subsequently, the boundary zone identification module identifies whether the unit is in the power supply boundary zone based on the unit's speed and operating status. Preferably, a power supply start-up threshold can be preset. and the stable threshold of power supply ,in, Greater than ,Right now: When the unit speed satisfy: Furthermore, if there are records of speed fluctuations, power supply switching, or unstable power generation status within the preset time window, the boundary zone identification module determines that the unit is in the power supply boundary zone operating condition.

[0049] After identifying the power supply boundary zone conditions, the wind speed trend judgment module determines whether the wind speed is on an upward trend based on wind speed data from multiple consecutive sampling times. Preferably, the wind speed change slope can be used. As a judgment metric: in, The wind speed at the current moment. For the front Wind speed corresponding to each sampling period The sampling period.

[0050] when Greater than the preset trend threshold At that time, that is: The wind speed is determined to be on an upward trend.

[0051] When the generator unit is operating in the power supply boundary zone and the wind speed is trending upward, the pre-pitch control module outputs a pre-pitch command, controlling the pitch actuator to briefly increase the pitch. Let the pitch angle before pre-pitch increase be... The initial pre-amplifier target angle is Then we have: in, This represents the initial pitch increment.

[0052] At the pitch angle Towards During the adjustment process, the pre-pitch response detection module continuously acquires the change in unit speed and calculates the speed reduction slope. Preferably, the speed reduction slope can be calculated in the following manner. : in, The unit speed at the current moment. For the front The unit speed corresponding to each sampling period The sampling period.

[0053] When the following conditions are met: When this occurs, it indicates that the unit speed is decreasing.

[0054] Meanwhile, the pre-pitch response detection module determines the pre-pitch response amount by combining the pitch angle change. Preferably, the pre-propeller response amount It can be determined based on the degree of speed reduction caused by a unit change in pitch, for example: in, The slope of the speed decrease, The rate of change of the pitch angle, To prevent a correction constant with a denominator of zero, the pre-propeller response quantity is used. The larger the value, the more sensitive the unit speed is to the pre-pitch adjustment; the pre-pitch response value... The smaller the value, the weaker the response of the unit speed to the pre-propeller action.

[0055] In other embodiments, pre-propeller response amount It can also be based on the speed decrease within a preset time window. With pitch angle change The ratio is determined, for example: in, This represents the amount of decrease in unit speed within a preset time window. This represents the change in pitch angle within the same time window.

[0056] The deceleration depth adjustment module adjusts the speed based on the pre-propeller response. And the current speed of the unit relative to the power supply start-up threshold The remaining difference Adjustments are made to the pre-steering target angle and / or pre-steering duration. The remaining difference... It can be represented as: in, This is the current speed of the generator unit.

[0057] When the pre-steering response Greater than the first response threshold And the remaining difference between the unit speed and the power supply start-up threshold Less than the preset difference At that time, that is: and: This indicates that the unit speed is close to the power supply start-up threshold and the response to pre-pitch increase is strong. At this time, the speed reduction depth adjustment module ends the pre-pitch increase stage in advance or reduces the pre-pitch increase target angle to avoid excessive speed drop.

[0058] When the pre-steering response Less than the second response threshold Furthermore, the unit speed is still higher than the power supply start-up threshold. At that time, that is: and: This indicates that the unit speed has a weak response to the pre-pitch increase. In this case, the speed reduction depth adjustment module extends the pre-pitch increase duration or increases the pre-pitch increase target angle to ensure that the unit speed can drop back below the power supply start-up threshold.

[0059] When the pre-steering response Located at the second response threshold With the first response threshold During this period, the deceleration depth adjustment module maintains the current pre-pitch control and continues to monitor the relationship between the unit speed and the power supply start-up threshold. Preferably, the first response threshold... Greater than the second response threshold ,Right now: During the pre-pitch increase process, if the unit speed drops back to the power supply start-up threshold... The pre-pitch control module then ends the current pre-pitch phase. If the pre-pitch duration reaches the preset upper limit and the unit speed still has not fallen below the power supply start-up threshold, the protection backoff module can stop the current pre-pitch control and, based on the wind speed trend and operating status, choose to maintain normal control, extend the power supply waiting time, or enter a conservative operating state.

[0060] Through the above process, the unit speed is controlled to fall below the power supply start-up threshold, but excessive speed reduction caused by fixed pre-pitch parameters is avoided. In other words, this embodiment does not simply increase the pitch angle to a fixed target angle, but uses the unit speed reduction response as a feedback signal during the pre-pitch increase process to determine the minimum necessary speed reduction depth.

[0061] like Figure 3 As shown, in this embodiment, a short-term increase in pitch causes a decrease in aerodynamic torque and a decrease in speed response. The pre-pitch response detection module determines the pre-pitch response amount based on the decrease in speed response, and the speed reduction depth adjustment module adjusts the pre-pitch target angle and / or the pre-pitch duration based on the pre-pitch response amount. When the unit speed drops below the power supply start-up threshold, the bidirectional converter enters the power supply mode, causing the generator to output torque assist. During the pitch recovery process, the aerodynamic torque increases, and the torque assist and aerodynamic torque are superimposed to drive the unit past the de-power supply stability threshold.

[0062] When the unit speed drops back to the power supply start-up threshold Subsequently, the power supply trigger control module controls the bidirectional converter to enter power supply mode and controls the generator to output auxiliary torque. At this point, the unit transitions from a single wind-driven state to a state boosted by grid-supply energy.

[0063] Preferably, the power supply trigger control module determines whether power supply has been successfully established based on the bidirectional converter mode feedback, generator current establishment status, or torque boosting torque establishment time. When the bidirectional converter feedback is in power supply mode, and the generator current or torque boosting torque reaches a preset establishment ratio, the power supply is determined to be successfully established.

[0064] After confirming the establishment of power supply, the torque boosting and pitch recovery coordination module adjusts the pre-increase pitch response based on the power supply status. Adjusting the torque booster and / or pitch recovery rate .

[0065] Let the third response threshold be The fourth response threshold is ,in Third response threshold and the fourth response threshold Used for coordinated control of torque boosting and pitch recovery after power supply mode is established; Specifically, when the pre-pitch response quantity This indicates that the unit is highly sensitive to pitch changes during the pre-pitch increase phase, and the speed drops rapidly. At this time, the torque assist and pitch recovery coordination module can reduce the torque assist torque. Or slow down the pitch recovery rate This is to avoid the aerodynamic torque from rising too quickly after the pitch is restored, which could cause a secondary fluctuation in the rotational speed.

[0066] When the pre-steering response This indicates that the unit's response to pitch changes is weak during the pre-pitch increase phase, and the current aerodynamic torque margin may be insufficient. In this case, the torque assist and pitch recovery coordination module can improve the torque assist. Extend the power supply duration and reduce the pitch recovery rate. This allows the unit to gradually increase its speed with the participation of auxiliary torque.

[0067] Preferably, the torque assist Based on the pre-steering response Make corrections: in, As the reference torque, This is the torque correction factor. The target response quantity. When Less than When, increase the auxiliary torque; when Greater than At this time, reduce the torque assist or maintain the reference torque assist.

[0068] Pitch recovery rate It can also be based on the pre-propeller response amount Make corrections: in, The reference pitch recovery rate, This is the pitch recovery correction factor. Greater than When, reduce the pitch recovery rate; when Less than At that time, the pitch recovery rate can be increased or maintained within a safe range.

[0069] During pitch recovery, the torque assist and pitch recovery coordination module controls the pitch angle to gradually recover from the pitch angle after pre-stagger to the working pitch angle before pre-stagger. Alternatively, it can be restored to the target working pitch angle recalculated based on the current wind speed. As the pitch is restored, the blade aerodynamic torque... The torque increases, and the torque output from the generator increases. These forces work together on the unit. At this time, the total driving torque of the unit... It can be represented as: In total driving torque Under this action, the unit speed increases and the power supply stabilizes at the threshold. Directional transition. Compared to control based solely on fixed pre-steering parameters, this embodiment can adjust the subsequent torque boost and pitch recovery process according to the actual speed response during the pre-steering phase, making the aerodynamic torque recovery process more aligned with the electrical torque boost process.

[0070] Once the unit speed increases, the stable power supply termination determination module judges whether the unit meets the termination conditions. Preferably, the following determination criterion can be adopted: the unit speed is continuously higher than the stable power supply termination threshold. Reaching the preset duration And the speed fluctuation amplitude during this period Not greater than the preset fluctuation threshold .

[0071] That is, simultaneously satisfying: When the above conditions are met, the stable power supply determination module controls the bidirectional converter to exit the power supply mode, so that the unit enters a stable power generation state.

[0072] If an anomaly occurs during the control process, the protection backoff module will execute backoff control. Specifically, this backoff will occur when the upward trend in wind speed disappears, the unit does not exceed the de-supply stability threshold within a preset time, and the pre-pitch response is activated. When the safety response threshold is exceeded, power supply establishment fails, or the unit experiences abnormal oscillations between power supply and de-supply, the protection backoff module can perform at least one of the following measures: prematurely terminate pre-pitch control, limit pitch recovery rate, extend power supply mode hold time, adjust torque booster, re-execute pre-pitch control, re-establish power supply mode, or temporarily lock the unit in conservative operation state to suppress repeated switching in the boundary zone.

[0073] In another embodiment, the unit controller can also update the first response threshold based on the control results of multiple power supply boundary zones within a preset time window. Second response threshold Initial pitch increment Reference torque and reference pitch recovery rate For example, when multiple control results show that the unit is prone to excessive speed reduction during the pre-pitch increment phase, the unit controller reduces the initial pitch increment. Or lower the first response threshold When multiple control results indicate that the unit is unable to return to below the power supply start-up threshold, the unit controller increases the initial pitch increment. Or extend the permitted pre-propeller duration.

[0074] In another embodiment, the unit controller can also adjust the pre-pitch response based on the pre-stress response. Slope of wind speed change Speed ​​fluctuation amplitude The risk level of the boundary area is determined by the number of mode switching times within a preset time window. When the risk level of the boundary area is low, the unit controller only performs small pre-pitch control; when the risk level of the boundary area is medium, the unit controller performs coordinated control of pre-pitch, power supply triggering, and pitch recovery; when the risk level of the boundary area is high, the unit controller extends the duration of the power supply mode or enters a conservative operation state to avoid repeated switching between the power supply mode and the power generation mode.

[0075] The above are merely specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, any modifications, equivalent substitutions, or improvements made to the above embodiments without departing from the technical concept of the present invention should fall within the protection scope of the present invention.

[0076] The scope of protection of this invention is defined by the claims, and the specification and drawings can be used to interpret the claims.

Claims

1. An optimal power generation collaborative control system for wind farms, characterized in that, It includes a wind speed detection unit, a speed detection unit, a pitch angle detection unit, an operating status detection unit, a unit controller, a pitch actuator, a bidirectional converter, and a generator; The unit controller is connected to the wind speed detection unit, the speed detection unit, the pitch angle detection unit, the operating status detection unit, the pitch actuator, and the bidirectional converter, respectively. The unit controller is configured as follows: When the unit speed is higher than the power supply start-up threshold and the power supply stabilization condition has not yet been met, the unit is determined to be in the power supply boundary zone operating condition. When the unit is in the power supply boundary zone and the wind speed is increasing, the pitch actuator is controlled to increase the pitch during the pre-pitch increase duration. During the pitch increase process, the pre-pitch increase response amount is determined based on the pitch angle change data and the unit speed decrease data; Based on the pre-steering response and the remaining speed difference between the current unit speed and the power supply start-up threshold, adjust the pre-steering target angle or the pre-steering duration to bring the unit speed back below the power supply start-up threshold. After the unit speed drops below the power supply start-up threshold, the bidirectional converter is controlled to enter the power supply mode, so that the generator outputs auxiliary torque. After the power supply mode is established, the torque booster set value and pitch recovery rate are determined according to the pre-increase pitch response amount, and the pitch actuator is controlled to restore the pitch according to the pitch recovery rate, so that the torque booster and the aerodynamic torque generated by the restored pitch jointly drive the unit speed to rise above the de-power supply stability threshold. After the unit meets the exit conditions, the bidirectional converter is controlled to exit the power supply mode; in case of abnormal operating conditions, rollback control is executed.

2. The optimal power generation coordinated control system for wind farms according to claim 1, characterized in that, The unit controller is configured to: when the unit speed is higher than the power supply start-up threshold and lower than the power supply stabilization threshold, determine the range of unit speed as a candidate boundary zone; within the candidate boundary zone, determine that the unit is in the power supply boundary zone operating condition based on at least two of the following: the speed fluctuation amplitude, the number of mode switching, and the bidirectional converter power supply status within a preset time window.

3. The optimal power generation coordinated control system for wind farms according to claim 1, characterized in that, The unit controller is configured to calculate the slope of wind speed change, the change of moving average, or the slope of linear fitting based on wind speed detection values ​​at multiple consecutive sampling times, and to determine that the wind speed is in an upward trend when the calculation result is greater than the wind speed rise threshold.

4. The optimal power generation coordinated control system for wind farms according to claim 1, characterized in that, The pre-pitch increase response is used to characterize the degree of decrease in unit speed corresponding to a unit pitch angle change; the unit controller is configured to determine the pre-pitch increase response based on the ratio of the decrease in unit speed to the change in pitch angle, or based on the ratio of the slope of the decrease in unit speed to the rate of change in pitch angle.

5. The optimal power generation coordinated control system for wind farms according to claim 1, characterized in that, The remaining speed difference is the difference between the current speed of the unit and the power supply start-up threshold; the unit controller is configured to: shorten the pre-pitch increase duration or reduce the pre-pitch increase target angle when the pre-pitch increase response is greater than the first response threshold and the remaining speed difference is less than the preset difference. When the pre-pitch response is less than the second response threshold and the current unit speed is still higher than the power supply start-up threshold, the pre-pitch duration is extended or the pre-pitch target angle is increased; wherein, the first response threshold is greater than the second response threshold.

6. The optimal power generation coordinated control system for wind farms according to claim 1, characterized in that, The unit controller is configured to control the bidirectional converter to provide driving power to the generator after the unit speed drops below the power supply start-up threshold, so that the generator outputs the auxiliary torque; and to determine whether the power supply mode is successfully established based on at least one of the bidirectional converter mode feedback, generator current establishment status, auxiliary torque establishment time, and torque feedback signal.

7. The optimal power generation coordinated control system for wind farms according to claim 1, characterized in that, The unit controller is configured to: reduce the torque booster setting value or reduce the pitch recovery rate when the pre-pitch booster response value is greater than a third response threshold; increase the torque booster setting value or extend the power supply duration and reduce the pitch recovery rate when the pre-pitch booster response value is less than a fourth response threshold; wherein the third response threshold is greater than the fourth response threshold; the unit controller is further configured to control the pitch actuator to start recovering the pitch after the torque booster reaches a preset establishment ratio.

8. The optimal power generation coordinated control system for wind farms according to claim 1, characterized in that, The exit conditions include: the unit speed continuously exceeds the power supply disconnection stability threshold for a stable confirmation period; the unit speed fluctuation amplitude is not greater than the preset fluctuation threshold; the bidirectional converter switching state is stable; and the unit output power meets the grid connection power generation requirements.

9. The optimal power generation coordinated control system for wind farms according to claim 1, characterized in that, The operating status detection unit is used to detect the power supply status of the bidirectional converter, the power generation status of the unit, the number of mode switching times within a preset time window, the speed fluctuation amplitude, the power supply establishment status, and the generator torque boosting torque establishment status.

10. The optimal power generation coordinated control system for wind farms according to claim 1, characterized in that, The abnormal operating conditions include at least one of the following: the wind speed rise trend is lower than the wind speed rise threshold, the unit speed does not reach the preset acceleration requirement after the power supply mode is established, the pre-pitch increase response exceeds the allowable response range, the power supply mode is not established within the preset establishment time, and the unit speed oscillation amplitude is greater than the oscillation threshold; the rollback control includes at least one of the following: stopping the pre-pitch increase control, limiting the pitch recovery rate, extending the power supply duration, adjusting the torque booster, re-executing the pre-pitch increase control, re-triggering the power supply mode, or switching the unit to a conservative operating state; the conservative operating state is an operating state that limits the pitch change rate and limits the upper limit of the torque booster.

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