A yaw motor pre-excitation control method for a wind turbine generator system

Abstract

The application discloses a yaw motor pre-excitation control method of a wind turbine, relates to the technical field of yaw control of a wind turbine, and aims to solve the influence of communication uncertainty on motor synchronization and avoid torque imbalance and structural fatigue, wherein a round-trip delay of a time-sensitive network switch is used to generate a delay mapping in real time, pre-excitation pulses with a trigger timestamp are issued to each motor based on the delay mapping and a global clock, when the actual arrival phase deviates from the predicted value by more than a threshold, a correction instruction is broadcast based on the slowest link, and the motor trigger phase is reset; the pre-excitation pulse width is dynamically adjusted according to the instantaneous torque of the motor and the three-phase flux linkage difference, when continuous delay jitter or abnormal packets are detected, a local fixed phase configuration is enabled, the abnormal link is isolated, and an alarm is reported. A continuous control chain from the network to the mechanical and electrical layer is constructed, the motor is ensured to be magnetized synchronously, and the power generation efficiency of the wind turbine during grid connection startup is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of yaw control of wind turbines, in particular to a pre-excitation control method for yaw motors of wind turbine generators. BACKGROUND

[0002] In modern large-scale wind farms, the yaw system is usually driven by multiple motors in parallel. Before starting, the brake must be released and a uniform magnetic field must be established through pre-excitation, which is the premise of smooth grid connection. The pre-excitation command relies on the rapid propagation of industrial Ethernet between the tower top control cabinet and each motor controller. In order to obtain sufficient real-time performance, the industry is gradually adopting methods such as time-sensitive network and precise time synchronization protocol to improve communication determinism. At the same time, new applications such as state monitoring, predictive maintenance, and digital twin continue to increase network load, introducing additional data traffic and complex interactions. Multiple public cases have shown that satellite link anomalies, gateway congestion, or network attacks have caused wind turbine control link failures, and operators have lost remote control of thousands of wind turbines in a short period of time, resulting in shutdowns and economic losses. Academic and industrial research has also shown that yaw angle errors can amplify blade loads and accelerate the fatigue of key components, so maintaining synchronized motor action is crucial for power yield and structural life.

[0003] When random delays, temporary congestion, or tampering by malicious nodes occur in internal communication, the arrival order of the pre-excitation pulse among the motors will be disrupted, some motors will establish a magnetic field in advance, while others will still be in a stationary state, and an uneven torque will be formed instantaneously. This torque deviation is transmitted to the nacelle through the gear ring, causing a slight but persistent bias in the yaw angle, and the angle of the blades facing the incoming flow gradually deviates from the optimal position, resulting in a decrease in power and an increase in vibration. Multiple wind tunnel tests and field measurements have shown that even a small and persistent yaw error can significantly increase blade bending moments and nacelle loads, accelerating fatigue accumulation. If the signal continues to be disturbed, the yaw system will frequently correct but be pulled back, causing gear meshing impacts and repeated cable twisting, further inducing early bearing spalling and brake wear, and ultimately triggering a protective shutdown or causing remote loss of control.

[0004] Therefore, it is urgent to build a collaborative control mechanism for the pre-excitation process around network timing stability and security, so that all drive units smoothly excite in the same time slot, fundamentally eliminating torque imbalance and yaw errors caused by communication anomalies. To this end, the present application provides a pre-excitation control method for yaw motors of wind turbine generators. SUMMARY

[0005] (I) Technical problems solved

[0006] In view of the deficiencies of the prior art, the application provides a yaw motor pre-excitation control method for a wind turbine generator set, a delay mapping is generated in real time by using the round-trip delay of a time-sensitive network switch, a pre-excitation pulse with a trigger time stamp is issued to each motor based on the delay mapping and a global clock, when the actual arrival phase deviates from the predicted value by more than a threshold, a correction instruction is broadcast based on the slowest link as a reference to reset the motor trigger phase, the pre-excitation pulse width is dynamically adjusted according to the instantaneous torque of the motor and the three-phase flux difference, when continuous time delay jitter or abnormal messages are detected, a local fixed phase configuration is enabled, the abnormal link is isolated and an alarm is reported. A continuous control chain from the network to the mechanical and electrical layer is constructed, the motor is ensured to be magnetized synchronously, the power generation efficiency of the wind turbine generator set during grid connection startup is improved, and the technical problems recorded in the background art are solved.

[0007] (II) Technical solutions

[0008] To achieve the above object, the application is implemented by the following technical solutions:

[0009] A yaw motor pre-excitation control method for a wind turbine generator set, comprising periodically sending a detection message to a switch, measuring the round-trip delay of each communication link and generating a link delay mapping table;

[0010] A global clock is obtained according to a time protocol, the sending time is calculated by subtracting the one-way delay from the predetermined trigger time, and a pre-excitation instruction message containing a trigger time stamp is sent to the corresponding yaw motor controller at the sending time;

[0011] The actual arrival time fed back by each controller is received, if the phase difference of any one exceeds the threshold, a new trigger time is obtained by adding an offset to the latest arrival time and a correction instruction is broadcasted;

[0012] The instantaneous torque and three-phase flux data of each yaw motor are received, the comprehensive difference is calculated according to the weight, and the pre-excitation pulse width of the next period is corrected;

[0013] The round-trip delay fluctuation and abnormal messages are monitored by a sliding window, when the fault tolerance condition is met, the local fixed phase is switched to and the synchronization and adjustment process is re-enabled after the link is restored.

[0014] Further, assuming that the uplink and downlink delays on the communication link are approximately equal, the detected round-trip delay is divided by two to obtain the one-way delay, and the one-way delay is recorded in the link delay mapping table for subsequent calculation of the sending time.

[0015] Further, the round-trip delay is re-measured according to a preset period and the one-way delay value in the mapping table is updated, when the detected round-trip delay exceeds the threshold, the current one-way delay is replaced by a historical average value or a default value and an abnormality is recorded.

[0016] Further, the pre-excitation instruction message contains a trigger timestamp field, which is used to instruct the yaw motor controller to perform the pre-excitation operation when the global clock reaches the predetermined trigger time, so as to ensure the synchronization of the actions of multiple motors.

[0017] Further, a phase window is set to adapt to slight fluctuations in the link, and the arrival time range allowed by the pre-excitation instruction message is specified, and the messages falling within the phase window are regarded as synchronous arrival, thereby reducing the yaw error.

[0018] Further, when the absolute value of the phase difference exceeds the threshold, the master control system selects the latest time among all actual arrival times, and broadcasts a correction instruction after adding a positive offset to the new trigger time.

[0019] Further, the instantaneous torque deviation and three-phase flux deviation of each yaw motor are superimposed as a comprehensive difference index according to preset torque weight and flux weight, which is used to guide the pre-excitation pulse width adjustment, so as to improve the output consistency.

[0020] Further, the comprehensive difference index is multiplied by a negative proportional coefficient to obtain a pre-excitation pulse width correction amount, and the correction amount is added to the current pulse width to form a new pulse width in the next cycle.

[0021] Further, a sliding window containing ten consecutive measurement cycles is used to calculate the difference between the maximum value and the minimum value of the round-trip delay of each communication link, and the difference is used as the delay fluctuation amplitude and used for jitter determination.

[0022] Further, when the delay fluctuation amplitude or the number of abnormal messages exceeds the corresponding threshold in consecutive cycles, the master control system broadcasts a switching instruction, and the yaw motor controller switches to a fixed phase mode based on the local clock, and the prediction synchronization and torque adjustment are re-enabled after the communication link is restored.

[0023] (Three) beneficial effects

[0024] The application provides a yaw motor pre-excitation control method for a wind turbine generator set, which has the following beneficial effects:

[0025] By the delay mapping acquisition step, the round-trip delay returned by the time-sensitive network switch is used to generate a link delay mapping table in real time, which provides an accurate time reference for subsequent synchronization calculation. The prediction synchronization trigger step combines the link delay mapping table and the precise time protocol global clock to issue a prediction pre-excitation pulse with a trigger timestamp for each yaw motor, so as to ensure that the control message can be synchronized to arrive at each motor controller within a predetermined phase window. By pre-compensating for the known delay difference, the phase consistency of the pre-excitation of multiple motors is significantly improved, and the synchronization error caused by communication delay is effectively reduced.

[0026] The self-correcting synchronization broadcast step can immediately broadcast correction instructions to all yaw motors when the difference between the actual arrival phase and the predicted value exceeds a set threshold, using the slowest link as the new time reference to reset the trigger phase of each motor, ensuring that even in unstable or sudden fluctuations in network conditions, the multi-motor can quickly recover to a synchronized state, avoiding control failure due to phase deviation accumulation.

[0027] The torque width adjustment step converts the dual difference between the instantaneous torque of the motor and the three-phase flux into a width correction amount by comprehensive analysis, and scales the pre-excitation pulse width of the next period in real time, which can effectively reduce the torque difference between the yaw motors, suppress the yaw angle bias phenomenon caused by torque imbalance, reduce the stress accumulation of mechanical parts due to torque fluctuations, thereby prolonging the service life of the key components of the yaw system.

[0028] When detecting continuous delay jitter or abnormal messages, the local fixed phase configuration can be quickly enabled, while isolating the abnormal link and reporting alarm information to the upper level, ensuring that the yaw motors can still maintain synchronized operation under extreme network failure conditions, avoiding damage to the system structure caused by torque mutations due to communication interruption or abnormalities. Through fast response and fault-tolerant processing, the safety and reliability of the system are improved, allowing the wind turbine to maintain a stable operating state in harsh environments. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The present application provides a wind turbine yaw motor pre-excitation control method flowchart. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0031] Please refer to Figure 1 The present application provides a wind turbine yaw motor pre-excitation control method, comprising,

[0032] Step one, the master system performs delay measurement on each communication link through the time-sensitive network switch, specifically, the master system sends a probe packet to the time-sensitive network switch at a predetermined period and records the sending time, after the time-sensitive network switch returns a response packet, the master system records the receiving time, and calculates the round-trip delay as the difference between the receiving time and the sending time; based on the uplink and downlink delay symmetry assumption of the communication link, the round-trip delay is divided by two to obtain the one-way delay; for each yaw motor controller, the master system records the corresponding one-way delay to the link delay mapping table; the master system repeats the delay measurement and one-way delay calculation at a predetermined period, and updates the one-way delay value in the link delay mapping table; the master system performs threshold detection on the round-trip delay of each communication link, if the round-trip delay exceeds the preset threshold, records the exception and uses the historical average one-way delay in the link delay mapping table or the preset default value to replace the current one-way delay.

[0033] The step one includes the following contents:

[0034] Step 101, round-trip delay measurement

[0035] In the yaw system of the wind turbine generator, the master system measures the delay of each communication link through the time-sensitive network switch to determine the real-time performance of the communication network.

[0036] The master system sends a probe packet to the time-sensitive network switch at a predetermined time interval, and records the sending time based on the local clock of the master system when sending the probe packet. After the time-sensitive network switch receives the probe packet, it immediately generates and returns a response packet. When the master system receives the response packet, it also records the receiving time based on the local clock of the master system. The calculation method of the round-trip delay is to subtract the sending time of the probe packet from the receiving time of the response packet to obtain the total time experienced by the probe packet from the master system to the receiving response packet.

[0037] By sending probe packets regularly and recording the sending and receiving times, the master system can accurately grasp the delay characteristics of the communication link. This method is based on the real-time performance of the time-sensitive network, ensuring that the measurement results reflect the current network status, providing a reliable data basis for subsequent one-way delay calculation. At the same time, the design of periodic measurement improves the dynamic adaptability of the system, which can timely capture the changes of network delay.

[0038] Step 102, one-way delay estimation

[0039] To determine the specific time for the pre-excitation command to propagate from the master system to each yaw motor controller, the master system needs to estimate the one-way latency of the communication link. Since directly measuring the one-way latency requires the master system and the yaw motor controller to have completely synchronized clocks, which is difficult to achieve in practical systems, a simplified estimation method is adopted. The master system assumes that the uplink delay and the downlink delay of the communication link are approximately equal, and divides the round-trip latency measured in the previous step by two, i.e. divides the total time of the round-trip latency by two, to obtain the estimated value of the one-way latency. This one-way latency represents the time required for the pre-excitation command to be transmitted from the master system to the yaw motor controller.

[0040] Based on the assumption of symmetry between the uplink and downlink delays, dividing the round-trip latency to estimate the one-way latency simplifies the calculation process and avoids the dependence on complex clock synchronization mechanisms. This method has high accuracy when the network load is relatively balanced, and is simple to calculate, allowing quick results and facilitating real-time system applications. Even if there is asymmetry in the network load, the subsequent real-time updating mechanism can gradually correct the deviation through multiple measurements.

[0041] Step 103, link delay mapping table generation

[0042] The master system performs round-trip latency measurement and one-way latency estimation for each communication link connecting the yaw motor controller and the time-sensitive network switch. Subsequently, the master system organizes and records the one-way latency data corresponding to each yaw motor controller into a centrally managed link delay mapping table, which contains the identification of all yaw motor controllers and their corresponding one-way latency values, forming a structured data set for subsequent synchronization control of the pre-excitation command.

[0043] By generating the link delay mapping table, the master system can centrally store and manage the one-way latency data of each communication link. This structured recording method facilitates quick querying and calling, improving the efficiency of the system in performing synchronization control. At the same time, the generation of the mapping table ensures that the delay characteristics of each yaw motor controller are completely recorded, providing a unified time reference for the implementation of multi-motor synchronous start.

[0044] Step 104, real-time updating mechanism

[0045] Since the communication network's delay can fluctuate due to load changes or environmental interference, the master system needs to continuously monitor and update the data in the link delay mapping table. Specifically, the master system repeatedly performs the round-trip delay measurement and one-way delay estimation process at a pre-set time interval, and writes the newly calculated one-way delay value into the link delay mapping table, overwriting the original record. The updated link delay mapping table reflects the latest state of the communication network, which is used to guide the master system to adjust the sending time of the pre-excitation command. The design of periodically updating the link delay mapping table can adapt to the dynamic changes of the communication network, ensuring that the one-way delay data is always consistent with the actual network status. This real-time nature enhances the adaptability and control accuracy of the system, avoiding synchronization errors caused by network delay fluctuations, thereby improving the stability and reliability of the yaw system.

[0046] Step 105, anomaly detection and processing

[0047] During the execution of the round-trip delay measurement process, the master system performs anomaly detection on the round-trip delay value of each communication link. The specific method is to pre-set a reasonable round-trip delay threshold value. If the round-trip delay of a communication link exceeds this threshold value, it is determined that the link has an anomaly. After detecting the anomaly, the master system records the abnormal state of the communication link and reports it to the system log, and at the same time takes emergency measures: temporarily replacing the one-way delay of the communication link with the historical average one-way delay value or the pre-set default value, and writing it into the link delay mapping table, to ensure the integrity and availability of the mapping table.

[0048] By threshold detection, the abnormal state of the communication link is discovered in time, avoiding the influence of false data caused by network failure or interference on the accuracy of synchronization control. Using the historical average value or the default value as a substitute processing method ensures that the system can still maintain normal operation in abnormal situations, enhancing the robustness and fault tolerance of the system, thereby ensuring the stability of the multi-motor cooperative work in the yaw system.

[0049] In use, by monitoring and recording the delay characteristics of the communication link in real time, accurate time basis is provided for the synchronization of the pre-excitation command. Specifically, the master control system periodically sends a probe packet to the time-sensitive network switch, records the sending and receiving time, calculates the round-trip delay, and based on the symmetry assumption, divides it into a one-way delay. Then, the master control system sorts the one-way delay data of each yaw motor controller into a link delay mapping table, and keeps the data real-time by regular updating. At the same time, the master control system performs threshold detection on the round-trip delay to handle abnormal situations and ensure the accuracy and integrity of the mapping table. Further, dynamic management of the communication link delay is achieved, enabling the master control system to adjust the sending time of the pre-excitation command according to the latest delay data, ensuring that all yaw motors receive the command within the same time period, thereby achieving synchronized pre-excitation, reducing torque imbalance and yaw error, and improving the operating efficiency and stability of the wind turbine.

[0050] Step two, the master control system extracts the one-way delay corresponding to each yaw motor controller from the link delay mapping table; the master control system synchronizes with the clock source in the tower network through the precision time protocol to establish a global clock reference; the master control system calculates the sending time for each yaw motor controller, and the calculation method is to subtract the one-way delay of the corresponding yaw motor controller from the predetermined trigger time; the master control system generates a pre-excitation command message for each yaw motor controller, which contains a trigger timestamp indicating that the yaw motor controller executes the pre-excitation operation when the global clock reference reaches the predetermined trigger time; the master control system sends the pre-excitation command message to the corresponding yaw motor controller when the global clock reference reaches the calculated sending time; the master control system sets a phase window to define the allowable arrival time range of the pre-excitation command message.

[0051] The step two includes the following contents:

[0052] Step 201, extract one-way delay data

[0053] In the yaw system of the wind turbine, the master control system obtains the one-way delay data corresponding to each yaw motor controller from the link delay mapping table generated in step one. The one-way delay represents the time required for the pre-excitation command to be transmitted from the master control system to the yaw motor controller, and the unit is milliseconds; the master control system obtains the one-way delay value of each communication link by querying the link delay mapping table, ensuring that the data reflects the latest situation of the current network state.

[0054] Extracting one-way delay data from the link delay mapping table ensures that the master control system uses real-time and accurate delay information when calculating the sending time later, avoiding synchronization errors caused by network delay fluctuations, thereby improving the stability and reliability of the yaw system.

[0055] Step 202, obtain global clock reference

[0056] The master system synchronizes with the clock source in the tower network through the precision time protocol to obtain a global clock reference in milliseconds. The global clock reference is a time standard shared by the master system and all yaw motor controllers, which is used to ensure the uniformity of time calculation.

[0057] Using the global clock reference ensures that the master system and all yaw motor controllers are consistent in time, avoiding inconsistent execution time of instructions due to clock deviation, improving the synchronization accuracy of the system, and providing a reliable time reference for the synchronous pre-excitation of multiple yaw motors.

[0058] To ensure that all yaw motor controllers receive the pre-excitation instruction at the same predetermined trigger time, the corresponding sending time is calculated for each yaw motor controller by subtracting the one-way delay of the yaw motor controller from the predetermined trigger time. The predetermined trigger time is a time point set in advance by the master system according to the system operation requirements, indicating that all yaw motor controllers should receive the pre-excitation instruction at this time point.

[0059] By subtracting the one-way delay from the predetermined trigger time to calculate the sending time, the pre-excitation instruction can be sent in advance according to the delay difference of each communication link, ensuring that the instruction reaches the yaw motor controller at the predetermined trigger time. This can effectively offset the inconsistency of communication delay and achieve synchronized arrival of the instruction, thereby reducing torque imbalance and yaw angle error caused by the difference in instruction arrival time.

[0060] Step 203, generating a pre-excitation instruction packet

[0061] A pre-excitation instruction packet is generated for each yaw motor controller, and a trigger timestamp is embedded in the packet. The trigger timestamp indicates that the yaw motor controller should perform the pre-excitation operation when the global clock reaches the predetermined trigger time.

[0062] Embedding the trigger timestamp in the pre-excitation instruction packet ensures that the yaw motor controller can perform the pre-excitation operation at the same time point after receiving the instruction based on the global clock, further enhancing the synchronization accuracy of multiple yaw motor controllers and reducing errors caused by inconsistent execution time of instructions.

[0063] According to the calculated sending time, the pre-excitation instruction packet with the trigger timestamp is sent to the corresponding yaw motor controller when the global clock reaches the sending time. By pre-offsetting the one-way delay, it is ensured that the instruction packet reaches the yaw motor controller at the predetermined trigger time. According to the sending time, the pre-excitation instruction packet is issued, ensuring that the instruction packet reaches the yaw motor controller at the predetermined trigger time. This method achieves synchronized issuance of instructions and ensures the time consistency of multiple yaw motors in pre-excitation operation, thereby improving the overall performance of the yaw system.

[0064] Step 204, setting phase window

[0065] To tolerate the slight fluctuation of network delay, the master control system sets a phase window with unit of millisecond. The phase window defines the allowable time range of the arrival of the pre-magnetization instruction message, i.e. the yaw motor controller should receive the instruction within a certain time before and after the scheduled trigger time. The specific value of the phase window is determined according to the real-time performance of the tower network and the synchronization accuracy requirement. Setting the phase window allows the network delay to fluctuate within a certain range, thereby improving the robustness of the system. This method ensures that even if the network delay changes slightly, the instruction message is still considered to be synchronized, thereby reducing the synchronization error caused by the fluctuation of network delay.

[0066] In use, the one-way delay data in the link delay mapping table generated in step one and the global clock reference are used to calculate and issue the pre-magnetization instruction message with trigger timestamp for each yaw motor controller; by calculating the sending time and combining the phase window, it is ensured that the instruction message arrives at each yaw motor controller within the scheduled time range, thereby achieving the synchronized pre-magnetization of multiple yaw motors. This process effectively offsets the communication delay difference, reduces the torque imbalance and yaw angle error caused by the inconsistent arrival time of the instruction, and improves the operation efficiency and accuracy of the yaw system.

[0067] Step three, the master control unit receives the feedback of the actual arrival time of the pre-magnetization instruction message from each yaw motor controller, calculates the phase difference between the actual arrival time and the scheduled trigger time; when the absolute value of any phase difference is greater than the preset phase difference threshold, the master control unit selects the latest time among all the actual arrival times as the new reference time, and adds a preset offset time to the new reference time to obtain a new trigger time; the master control unit broadcasts the correction instruction message containing the new trigger time to all yaw motor controllers, and each yaw motor controller executes the pre-magnetization operation according to the new trigger time in the correction instruction message when the global clock reference reaches the new trigger time.

[0068] The step three includes the following contents:

[0069] Step 301, recording actual arrival time

[0070] In the yaw system of the wind turbine, each yaw motor controller records the actual arrival time of the pre-excitation instruction message after receiving the pre-excitation instruction message sent in step two. The actual arrival time is based on the global clock provided by the precise time protocol, and the time unit is millisecond; after the recording is completed, each yaw motor controller feeds back the actual arrival time to the master control unit through the communication link. By recording the actual arrival time of the pre-excitation instruction message and feeding it back to the master control unit, the master control unit can master the arrival of the pre-excitation instruction message at each yaw motor controller in real time, providing accurate data support for subsequent calculation of phase difference and detection of deviation, ensuring that the inconsistency of the arrival time of the pre-excitation instruction message can be found in time, thereby improving the synchronization accuracy and operation stability of the yaw system.

[0071] After the master control unit receives the actual arrival time fed back by each yaw motor controller, it calculates the phase difference of each pre-excitation instruction message, which is the time difference between the actual arrival time and the predetermined trigger time in step two. The predetermined trigger time is the time point at which the master control unit sets for all yaw motor controllers to receive the pre-excitation instruction message. By calculating the phase difference between the actual arrival time and the predetermined trigger time, the master control unit can quantify the degree of deviation of the arrival time of the pre-excitation instruction message. This quantification provides a clear basis for determining whether synchronization correction is needed, enabling the system to adjust the synchronization strategy according to the actual network status, thereby enhancing the adaptive ability and reliability of the yaw system.

[0072] Step 302, compare the phase difference with the threshold

[0073] The master control unit sets a phase difference threshold in advance, with the time unit being millisecond, as a threshold for judging whether the deviation of the arrival time of the pre-excitation instruction message is within an acceptable range. The master control unit detects the phase difference of each yaw motor controller, and if it finds that the absolute value of the phase difference of any yaw motor controller is greater than the phase difference threshold, it considers that the deviation of the arrival time of the pre-excitation instruction message exceeds the allowed range, and needs to start the correction process.

[0074] By setting the phase difference threshold and comparing it with the phase difference of each yaw motor controller, the master control unit can timely detect the synchronization error caused by network delay fluctuation. This detection mechanism triggers the correction process, ensuring that the system can maintain synchronization accuracy when the network status is unstable, thereby reducing the torque imbalance and yaw angle error caused by the inconsistency of the arrival time of the pre-excitation instruction message.

[0075] Step 303, determine the slowest link reference time

[0076] When the master control unit detects that the phase difference of any yaw motor controller exceeds the phase difference threshold, the latest actual arrival time is selected from the actual arrival times fed back from all yaw motor controllers, and the latest actual arrival time is set as the new reference time. The new reference time serves as the time reference for subsequent synchronization adjustment. Selecting the latest actual arrival time as the new reference time ensures that the pre-excitation instruction messages of all yaw motor controllers arrive before or at the same time as the reference time, avoiding synchronization errors caused by some yaw motor controllers executing pre-excitation operations too early, thereby improving the synchronization accuracy of the yaw system and reducing torque imbalance and yaw angle errors.

[0077] The master control unit calculates new trigger times for all yaw motor controllers based on the new reference time. The calculation method is to add a preset offset time to the new reference time. The offset time is positive and the time unit is milliseconds, ensuring that the new trigger time is after the current global clock and avoiding immediate execution of the pre-excitation instruction message. By adding a preset offset time to the new reference time to calculate the new trigger time, the master control unit sets a unified future execution time point for all yaw motor controllers. This setting ensures that all yaw motor controllers can execute pre-excitation operations synchronously within the same time period, thereby improving the synchronization accuracy and operational stability of the yaw system.

[0078] Step 304, issue correction instruction

[0079] The master control unit issues a correction instruction message to all yaw motor controllers through broadcasting. The correction instruction message contains the new trigger time. After receiving the correction instruction message, each yaw motor controller updates the execution time of the pre-excitation operation to the new trigger time. By broadcasting the correction instruction message containing the new trigger time, the master control unit can quickly and uniformly adjust the execution time of the pre-excitation operation of all yaw motor controllers. This adjustment ensures that all yaw motor controllers execute the pre-excitation operation within the same time period, thereby improving the response speed and synchronization accuracy of the system and reducing errors caused by inconsistent execution times.

[0080] Each yaw motor controller executes the pre-excitation operation synchronously at the new trigger time based on the updated new trigger time. The execution of the pre-excitation operation ensures that the pre-excitation pulses of all yaw motors are completed within the same time period.

[0081] By executing the pre-excitation operation at the unified new trigger time, all yaw motor controllers can enter the pre-excitation state synchronously and establish a uniform magnetic field. This synchronous execution method ensures smooth grid connection, thereby improving the synchronization accuracy and stability of the yaw system and further improving the operational efficiency and reliability of the wind turbine generator.

[0082] When in use, the phase difference between the actual arrival time of the pre-excitation instruction message and the scheduled triggering time is monitored in real time, and compared with the preset phase difference threshold, so as to accurately detect the arrival time deviation caused by communication delay fluctuation. When the deviation exceeds the allowable range, the main control unit takes the latest actual arrival time as the new reference time, calculates and broadcasts a new triggering time, so that all yaw motor controllers synchronously perform the pre-excitation operation in the same time period in the future. In this way, the pre-excitation pulse time misalignment caused by network uncertainty can be effectively eliminated, and the operation stability of the yaw system and the overall efficiency of the wind turbine generator set are ensured.

[0083] Step four, the main control unit receives the instantaneous torque and three-phase flux data uploaded by each yaw motor controller through the synchronous communication link. The main control unit calculates the deviation of the instantaneous torque of each yaw motor from the average value of the instantaneous torque of all yaw motors and the comprehensive deviation of the three-phase flux from the preset standard three-phase flux. The main control unit integrates the torque deviation and the flux comprehensive deviation into a comprehensive difference index through a preset weight coefficient. The main control unit calculates the correction amount of the pre-excitation pulse width according to the comprehensive difference index and a preset proportional control coefficient. The main control unit applies the correction amount to the current pre-excitation pulse width to determine the pre-excitation pulse width of the next period. The main control unit sends the adjusted pre-excitation pulse width to each yaw motor controller through the synchronous communication link.

[0084] The step four includes the following contents:

[0085] Step 401, collect instantaneous torque and three-phase flux data

[0086] In the yaw system of a wind turbine generator set, each yaw motor controller monitors and records the instantaneous torque and three-phase flux of the corresponding yaw motor in real time through the built-in sensor. The instantaneous torque represents the current output torque of the yaw motor, and the unit is Newton-meter. The three-phase flux corresponds to the A phase, B phase and C phase of the yaw motor respectively, and the unit is Weber, which represents the strength and distribution of the motor magnetic field. The data collected by the sensor is uploaded to the main control unit through the synchronous communication link for subsequent processing.

[0087] Real-time collection of instantaneous torque and three-phase flux data enables the main control unit to accurately grasp the running state of each yaw motor. This method provides real-time and reliable data support for subsequent analysis of torque and flux differences, ensuring that the system can respond to dynamic changes in the yaw motor in a timely manner, thereby improving the synchronization accuracy and operation stability of the yaw system.

[0088] The master control unit receives the instantaneous torque data uploaded by each yaw motor controller, and calculates the deviation of the instantaneous torque of each yaw motor from the average value of the instantaneous torques of all yaw motors. The average value of the instantaneous torques is obtained by adding the instantaneous torque values of all yaw motors and dividing by the total number of yaw motors. The torque difference represents the degree to which the instantaneous torque of a certain yaw motor deviates from the overall average level, with units of newton-meters. Calculating the torque difference can quantify the unevenness of the instantaneous torques of the yaw motors, which clearly reflects the output differences between the yaw motors, enabling the system to make targeted adjustments based on the degree of torque imbalance, thereby reducing yaw angle errors caused by inconsistent torques.

[0089] Step 402, calculate three-phase flux linkage difference

[0090] After the master control unit receives the three-phase flux linkage data uploaded by each yaw motor controller, it calculates the comprehensive deviation of the three-phase flux linkage of each yaw motor from the preset standard three-phase flux linkage. The comprehensive deviation is obtained by first calculating the differences between the A-phase, B-phase, and C-phase flux linkages and the corresponding standard values, adding the squares of these three differences, and then taking the square root, with units of webers. The standard three-phase flux linkage value is determined by design parameters or calibration experiments and serves as a reference benchmark for ideal magnetic field distribution.

[0091] Calculating the three-phase flux linkage difference allows for the assessment of the degree to which the magnetic field distribution of each yaw motor deviates from the ideal state. This assessment reflects the impact of magnetic field inconsistency on motor operation, enabling the system to adjust the control strategy based on the flux linkage deviation, thereby ensuring the uniformity of the magnetic field distribution of the yaw motors.

[0092] The master control unit integrates the torque difference and the three-phase flux linkage difference into a comprehensive difference index.

[0093] The specific calculation method is as follows: first, take the absolute value of the torque difference and multiply it by a pre-set torque weight coefficient, then multiply the three-phase flux linkage difference by a pre-set flux linkage weight coefficient, and finally add the two results to obtain the comprehensive difference index. The torque weight coefficient and the flux linkage weight coefficient are pre-calibrated based on the characteristics and operating conditions of the yaw motors and are used to adjust the contribution proportion of torque and flux linkage to the comprehensive difference index. Integrating the torque difference and the three-phase flux linkage difference into the comprehensive difference index allows for the unified measurement of the operating inconsistency of the yaw motors. This comprehensive evaluation method takes into account both torque and flux linkage, enabling a more comprehensive judgment of the operating state of the yaw motors and thereby optimizing the accuracy of subsequent control adjustments.

[0094] Step 403, calculate pre-magnetizing pulse width correction amount

[0095] The master control unit calculates the correction amount of the pre-magnetizing pulse width based on the comprehensive difference index.

[0096] The specific calculation method is: multiplying the comprehensive difference index by a pre-set negative proportional control coefficient to obtain a correction amount, which is in units of milliseconds. The proportional control coefficient is determined according to the system response time and the yaw motor characteristics, and is used to control the response sensitivity of the correction amount to the comprehensive difference index. Calculating the pre-excitation pulse width correction amount achieves the purpose of dynamically adjusting the control parameters according to the inconsistency of the yaw motor operation. This adjustment method matches the change of the pulse width with the deviation degree of the torque and the flux linkage, thereby effectively reducing the difference and suppressing the generation of the yaw angle bias.

[0097] The main control unit applies the calculated pre-excitation pulse width correction amount to the pre-excitation pulse width of the next period. The specific adjustment method is: adding the pre-excitation pulse width of the current period to the correction amount to obtain the pre-excitation pulse width of the next period, which is in units of milliseconds. The initial value of the pre-excitation pulse width of the current period is provided by the synchronization instruction. Adjusting the pre-excitation pulse width realizes real-time correction of the pre-excitation operation of the yaw motor, so that the torque and the flux linkage of each yaw motor gradually tend to be consistent, thereby improving the synchronization accuracy and operation stability of the yaw system and reducing the error caused by the operation difference.

[0098] Step 404, issuing an adjustment instruction

[0099] The main control unit issues the adjusted pre-excitation pulse width to each yaw motor controller through the synchronization communication link. Each yaw motor controller applies the received pre-excitation pulse width in the pre-excitation operation of the next period to ensure that the real-time correction of the torque and the flux linkage is implemented. Issuing the adjustment instruction realizes the unified and coordinated control of the main control unit over each yaw motor controller. This method ensures that all yaw motors synchronously execute the adjusted pulse width in the pre-excitation operation of the next period, thereby improving the overall synchronization accuracy and operation efficiency of the yaw system.

[0100] In use, first, the instantaneous torque and three-phase flux linkage data of each yaw motor are collected in real time; then, the torque difference and the three-phase flux linkage difference are calculated respectively and integrated into a comprehensive difference index; then, the correction amount of the pre-excitation pulse width is calculated according to the comprehensive difference index, and the pre-excitation pulse width of the next period is adjusted; finally, the adjustment result is issued to each yaw motor controller for execution, which can effectively reduce the torque unevenness and the flux linkage difference caused by mechanical characteristics or network fluctuations, suppress the generation of the yaw angle bias, and ensure the synchronization and structural life of the yaw system.

[0101] Step five, the master control unit calculates the round-trip delay fluctuation amplitude of the communication link by the sliding window method and compares it with the preset threshold value in a plurality of continuous periods to determine the sustained time delay jitter, while performing checksum comparison and sequence number verification on the pre-magnetizing instruction message and counting the number of abnormal messages in the continuous message period to determine the sustained abnormal message; when the sustained time delay jitter or the sustained abnormal message is determined, the master control unit starts the fault-tolerant switching process, which specifically includes enabling the local fixed phase configuration, isolating the abnormal communication link and reporting the alarm; the yaw motor controller performs the pre-magnetizing operation according to the local clock and the fixed phase configuration; the master control unit continuously monitors the communication link state and issues a recovery instruction to re-enable the predictive synchronization and torque adjustment process after the communication link recovers to normal.

[0102] The step five includes the following contents:

[0103] Step 501, monitoring the round-trip delay fluctuation of the communication link

[0104] In the yaw system of the wind turbine generator, the master control unit uses the link delay mapping table generated in step one to collect the round-trip delay of each communication link in real time. The round-trip delay represents the time of message transmission between the master control unit and the yaw motor controller, and the unit is millisecond. The master control unit analyzes the fluctuation amplitude of the round-trip delay of each communication link in the recent plurality of periods by the sliding window method. The fluctuation amplitude is defined as the difference between the maximum value and the minimum value of the round-trip delay in the preset sliding window period number. The sliding window period number is set to 10 periods to ensure that the system can respond to the dynamic changes of the communication link in real time at the millisecond level. By monitoring the fluctuation amplitude of the round-trip delay by the sliding window method, the master control unit can accurately capture the short-term fluctuation trend of the communication link delay. This method can effectively identify the sustained time delay jitter when dealing with the randomness of network delay, providing a reliable trigger basis for fault-tolerant switching, thereby improving the stability and reliability of the yaw system.

[0105] The master control unit performs content integrity verification on the received pre-magnetizing instruction message, including checksum comparison and sequence number verification. The checksum comparison is performed by calculating the checksum of the received message and comparing it with the checksum field carried in the message. If they are not consistent, it is determined to be an abnormal message. The sequence number verification is performed by checking whether the increasing sequence number in the message is continuous with the sequence number of the last valid message. If there is a jump or repetition, it is determined to be an abnormal message. The master control unit counts the number of abnormal messages in the continuous message period. If the number of abnormal messages exceeds the preset threshold value, it is determined that there is a sustained abnormal message. Through checksum comparison and sequence number verification, the master control unit can timely find the tampering or loss of the message in the transmission process. This detection mechanism can effectively identify abnormal messages caused by network attacks or communication link failures while ensuring the integrity and sequence of the message, providing an accurate trigger signal for fault-tolerant switching, thereby ensuring the safety and stability of the yaw system.

[0106] Step 502, triggering fault-tolerant switching

[0107] When the master unit detects that the fluctuation amplitude of the round-trip delay of any communication link exceeds the preset threshold value for consecutive multiple periods, or the number of abnormal messages exceeds the preset threshold value for consecutive message periods, the fault-tolerant switching process is immediately started.

[0108] The fault-tolerant switching process includes enabling a local fixed phase configuration, isolating an abnormal communication link, and reporting an alarm. When the local fixed phase configuration is enabled, the master unit issues a switching instruction to all yaw motor controllers through broadcasting, and each controller switches to the locally stored fixed phase configuration, including the pre-excitation pulse width and the trigger time. When the abnormal communication link is isolated, the master unit disables the communication interface of the abnormal link through the time-sensitive network switch. When the alarm is reported, the master unit generates alarm information and uploads it to the remote monitoring center through the backup channel.

[0109] By triggering fault-tolerant switching, the master unit can quickly take emergency measures when the communication link is abnormal, and enable the local fixed phase configuration to ensure that the yaw motor controllers execute the pre-excitation operation synchronously under the local clock. This way avoids the disorder of command transmission caused by abnormal communication links, thereby maintaining the synchronization of the yaw system and preventing torque imbalance from causing yaw angle bias and structural fatigue.

[0110] Step 503, executing local pre-excitation

[0111] After each yaw motor controller receives the switching PRIME, it executes the pre-excitation pulse at a fixed trigger time and a fixed pre-excitation pulse width according to the local clock, ensuring that all yaw motors complete the excitation operation within the same time period. The local clock is synchronized with the global clock through the precise time protocol, ensuring the accuracy of the trigger time.

[0112] Executing local pre-excitation allows the yaw motor controller to still rely on local configuration and clock to execute synchronous pre-excitation operation when the communication link is abnormal. This way ensures the continuous operation of the yaw system when the network fails, preventing pre-excitation failure caused by communication interruption, thereby improving the reliability and safety of the wind turbine generator.

[0113] The master unit continuously monitors the round-trip delay and message state of the abnormal communication link. If the fluctuation amplitude of the round-trip delay of the abnormal communication link is lower than the preset threshold value for consecutive multiple periods and there is no abnormal message, it is determined that the communication link has recovered to normal. The master unit issues a recovery instruction to the yaw motor controller to re-enable the predictive synchronization and torque adjustment process.

[0114] By continuously monitoring the communication link status, the master unit can switch back to the normal control mode in time after the communication link is restored. This adaptive recovery mechanism ensures that the yaw system can re-use the centralized control advantage of the master unit when the network condition improves, thereby optimizing the synchronization accuracy and operating efficiency of the yaw motor.

[0115] In use, by monitoring the communication link round-trip delay fluctuation and message integrity, continuous delay jitter or abnormal messages are detected, and local fixed phase configuration is enabled, abnormal communication links are isolated and alarms are reported in abnormal conditions, to maintain the pre-excitation synchronization of multiple yaw motors and prevent torque imbalance. This step ensures the continuous and stable operation of the yaw system through localized operation and link isolation when the communication link is abnormal, ensuring the safety of the grid-connected start of the wind turbine generator set and the power generation efficiency.

[0116] Those skilled in the art can appreciate that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0117] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.

[0118] In the several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection between each of the units can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or in other forms.

[0119] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e. they can be located in one place or distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0120] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of yaw motor pre-excitation control for a wind turbine generator system, characterized by: Comprising Step one, the master system performs delay measurement on each communication link through the time-sensitive network switch, specifically, the master system sends a probe packet to the time-sensitive network switch at a predetermined period and records the sending time, after the time-sensitive network switch returns a response packet, the master system records the receiving time, and calculates the round-trip delay as the difference between the receiving time and the sending time; based on the uplink and downlink delay symmetry assumption of the communication link, the round-trip delay is divided by two to obtain the one-way delay; for each yaw motor controller, the master system records the corresponding one-way delay to the link delay mapping table; the master system repeats the delay measurement and one-way delay calculation at a predetermined period, and updates the one-way delay value in the link delay mapping table; The master system performs threshold detection on the round-trip delay of each communication link, and if the round-trip delay exceeds the preset threshold, records the exception and uses the historical average one-way delay in the link delay mapping table or the preset default value to replace the current one-way delay; Step two, the master system extracts the one-way delay corresponding to each yaw motor controller from the link delay mapping table; The master system synchronizes with the clock source in the tower network through the precision time protocol to establish a global clock reference; The master system calculates the sending time for each yaw motor controller, and the calculation method is to subtract the one-way delay of the corresponding yaw motor controller from the predetermined trigger time; The master system generates a pre-magnetizing instruction packet for each yaw motor controller, which contains a trigger timestamp indicating that the yaw motor controller performs a pre-magnetizing operation when the global clock reference reaches the predetermined trigger time; the master system sends the pre-magnetizing instruction packet to the corresponding yaw motor controller when the global clock reference reaches the calculated sending time; the master system sets a phase window to define the arrival time range allowed by the pre-magnetizing instruction packet; Step three, the master unit receives the actual arrival time feedback of the pre-magnetizing instruction packet from each yaw motor controller, and calculates the phase difference between the actual arrival time and the predetermined trigger time; when the absolute value of any phase difference is greater than the preset phase difference threshold, the master unit selects the latest time among all actual arrival times as a new reference time, and adds a preset offset time to the new reference time to obtain a new trigger time; the master unit broadcasts a correction instruction packet containing the new trigger time to all yaw motor controllers, and each yaw motor controller performs a pre-magnetizing operation at the new trigger time based on the new trigger time in the correction instruction packet. Step four, the master control unit receives the instantaneous torque and three-phase flux data uploaded by each yaw motor controller through the synchronous communication link, the master control unit calculates the deviation of the instantaneous torque of each yaw motor from the average value of the instantaneous torque of all yaw motors and the comprehensive deviation of the three-phase flux from the preset standard three-phase flux, the master control unit integrates the torque deviation and the flux comprehensive deviation into a comprehensive difference index through a preset weight coefficient, the master control unit calculates the correction amount of the pre-magnetizing pulse width according to the comprehensive difference index and a preset proportional control coefficient, the master control unit applies the correction amount to the current pre-magnetizing pulse width to determine the pre-magnetizing pulse width of the next period, and the master control unit sends the adjusted pre-magnetizing pulse width to each yaw motor controller through the synchronous communication link; Step five, the master control unit calculates the round-trip delay fluctuation amplitude of the communication link by the sliding window method and compares it with the preset threshold in continuous multiple periods to determine the continuous time delay jitter, at the same time, the master control unit performs checksum comparison and sequence number verification on the pre-magnetizing instruction message and counts the number of abnormal messages in continuous message periods to determine the continuous abnormal messages; When it is determined that the continuous time delay jitter or the continuous abnormal messages, the master control unit starts the fault-tolerant switching process, which specifically includes enabling the local fixed phase configuration, isolating the abnormal communication link and reporting the alarm; the yaw motor controller performs the pre-magnetizing operation according to the local clock and the fixed phase configuration; The master control unit continuously monitors the communication link state, and sends a recovery instruction to re-enable the prediction synchronization and torque adjustment process after the communication link recovers to normal.

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