A method and system for offshore wind turbine cathodic protection control based on double time scale

Abstract

The application provides a kind of offshore wind turbine cathodic protection control method and system based on double time scale, it is related to offshore wind power equipment corrosion protection control field, the method comprises: obtaining protection potential, tidal level, seawater velocity, seawater temperature and cathodic protection power supply operating data;Based on protection potential, tidal level and seawater velocity, short time scale working condition identification is carried out, and the operating condition is determined;Based on seawater temperature and power supply output voltage and current, the equivalent polarization impedance is determined, and the control reference parameter is updated accordingly;According to the working condition, the corresponding control parameter is called, the target control parameter is generated by combining the updated reference, the control quantity is determined and the power supply output is adjusted.The technical problem that the prior art cannot consider short cycle high frequency environmental disturbance quick response and long cycle reference drift adjustment is solved.

Description

Technical Field

[0001] This application relates to the field of corrosion protection and control of offshore wind power equipment, and in particular to a cathodic protection control method and system for offshore wind turbines based on dual time scales. Background Technology

[0002] To ensure the long-term safety of offshore wind turbine support structures, impressed current cathodic protection (ICCP) technology is widely used in engineering. Its core control device is a potentiostat, which collects the deviation between the reference electrode potential and the preset protection potential in real time, and uses a PID controller to adjust the output current, ensuring the protected steel structure remains within the protection potential range. Currently, most potentiostats use control systems based on conventional incremental PID algorithms, where the proportional, integral, and derivative parameters are statically fixed after factory commissioning, and the protection potential setpoint is controlled using a single reference operating point. However, offshore wind turbine foundations are fixed in the marine environment, encountering drastic short-period nonlinear characteristics such as tidal levels and seawater currents that change rapidly on a second to minute basis. Meanwhile, seawater temperature, aging of anti-corrosion coatings, and marine organism attachment slowly alter the electrochemical impedance characteristics of the foundation over long periods of months to years. Existing fixed-parameter PID control strategies exhibit slow response and are prone to control overshoot and oscillations during rapid tides or severe sea conditions. Furthermore, they fail to adaptively adjust the reference protection potential and control parameters during seasonal temperature variations or coating aging, leading to frequent deviations of the protection potential from the ideal range and unstable corrosion protection performance. Therefore, a method is urgently needed to address the technical challenge of simultaneously achieving rapid response to short-cycle, high-frequency environmental disturbances and long-cycle reference drift adjustment in existing technologies. Summary of the Invention

[0003] This application provides a cathodic protection control method and system for offshore wind turbines based on dual time scales, which solves the technical problem that existing technologies cannot simultaneously achieve rapid response to short-period high-frequency environmental disturbances and long-period reference drift adjustment.

[0004] To achieve the above objectives, this application adopts the following technical solution: Firstly, a method for controlling cathodic protection of offshore wind turbines based on dual time scales is provided. The method includes: acquiring protection potential data, environmental monitoring data, and cathodic protection power supply operation data of the offshore wind turbine foundation; wherein the environmental monitoring data includes tide level data, seawater flow velocity data, and seawater temperature data, and the cathodic protection power supply operation data includes the output voltage and output current of the cathodic protection power supply; identifying short-time-scale operating conditions based on the protection potential data, tide level data, and seawater flow velocity data to determine the current cathodic protection operating condition; determining the equivalent polarization impedance of the wind turbine foundation based on the seawater temperature data and the output voltage and output current of the cathodic protection power supply, and updating the cathodic protection control reference parameters according to the seawater temperature data and the equivalent polarization impedance; calling the corresponding control parameters according to the current cathodic protection operating condition, and generating target control parameters by combining the updated cathodic protection control reference parameters; determining the cathodic protection control quantity according to the protection potential data, the target control parameters, and a preset control algorithm, and adjusting the output of the cathodic protection power supply according to the cathodic protection control quantity.

[0005] In conjunction with the first aspect mentioned above, in one possible implementation, short-timescale operating condition identification is performed based on protection potential data, tide level data, and seawater flow velocity data to determine the current cathodic protection operating condition. This includes: calculating the tidal level fluctuation rate based on tidal level data from multiple consecutive sampling times, and inputting the tidal level fluctuation rate and seawater flow velocity data into the operating condition state machine; the operating condition state machine compares the seawater flow velocity data with a preset flow velocity threshold; when the seawater flow velocity data is greater than the preset flow velocity threshold, the current cathodic protection operating condition is determined to be a severe sea state; when the seawater flow velocity data is not greater than the preset flow velocity threshold, the operating condition state machine determines the current cathodic protection operating condition to be a tidal steady-state condition or a tidal fluctuation condition based on the tidal level fluctuation rate and a preset hysteresis judgment rule.

[0006] In conjunction with the first aspect above, in one possible implementation, the operating state machine determines whether the current cathodic protection operating condition is a tidal steady-state condition or a tidal fluctuating condition based on the tidal level fluctuation rate and a preset hysteresis judgment rule. This includes: setting a first fluctuation rate threshold and a second fluctuation rate threshold corresponding to the tidal level fluctuation rate, wherein the first fluctuation rate threshold is greater than the second fluctuation rate threshold; when the current cathodic protection operating condition is a tidal steady-state condition and the tidal level fluctuation rate is greater than the first fluctuation rate threshold, the current cathodic protection operating condition is determined to be a tidal fluctuating condition; when the current cathodic protection operating condition is a tidal fluctuating condition and the tidal level fluctuation rate is less than the second fluctuation rate threshold, the current cathodic protection operating condition is determined to be a tidal steady-state condition; and when the tidal level fluctuation rate is greater than or equal to the second fluctuation rate threshold and less than or equal to the first fluctuation rate threshold, the current cathodic protection operating condition remains unchanged.

[0007] In conjunction with the first aspect mentioned above, in one possible implementation, the equivalent polarization impedance of the wind turbine foundation is determined based on seawater temperature data and the output voltage and current of the cathodic protection power supply. The cathodic protection control reference parameters are then updated based on the seawater temperature data and the equivalent polarization impedance. This includes: statistically processing seawater temperature data collected over a preset long-term evaluation period to obtain an average seawater temperature; determining the equivalent polarization impedance of the wind turbine foundation based on the output voltage and current of the cathodic protection power supply; determining a temperature drift coefficient based on the average seawater temperature and an impedance aging coefficient based on the equivalent polarization impedance; and correcting the preset cathodic protection control reference parameters based on the temperature drift coefficient and the impedance aging coefficient to obtain updated cathodic protection control reference parameters.

[0008] In conjunction with the first aspect above, in one possible implementation, the temperature drift coefficient is determined based on the average seawater temperature, and the impedance aging coefficient is determined based on the equivalent polarization impedance. This includes: comparing the average seawater temperature with a preset standard ambient temperature to determine the temperature deviation; calculating the temperature drift coefficient based on the temperature deviation and a preset temperature correction model; comparing the equivalent polarization impedance with a preset standard polarization impedance to determine the impedance deviation; and calculating the impedance aging coefficient based on the impedance deviation and a preset impedance correction model.

[0009] In conjunction with the first aspect mentioned above, in one possible implementation, the preset cathodic protection control reference parameters are corrected based on the temperature drift coefficient and the impedance aging coefficient to obtain updated cathodic protection control reference parameters. This includes: obtaining preset cathodic protection control reference parameters under standard conditions, which include a protection potential reference value and corresponding PID control parameters; compensating the protection potential reference value based on the temperature drift coefficient to obtain an updated protection potential reference value; compensating the PID control parameters based on the impedance aging coefficient to obtain updated PID control parameters; and using the updated protection potential reference value and the updated PID control parameters as the updated cathodic protection control reference parameters.

[0010] In conjunction with the first aspect mentioned above, in one possible implementation, the corresponding control parameters are invoked based on the current cathodic protection operating condition, and the target control parameters are generated by combining them with the updated cathodic protection control reference parameters. This includes: invoking the PID control parameters corresponding to the current cathodic protection operating condition from a preset operating condition parameter library based on the current cathodic protection operating condition; determining whether the cathodic protection operating condition at the current sampling time is consistent with the cathodic protection operating condition at the previous sampling time; when the cathodic protection operating condition at the current sampling time is consistent with the cathodic protection operating condition at the previous sampling time, combining the invoked PID control parameters with the updated cathodic protection control reference parameters to generate the target control parameters; when the cathodic protection operating condition at the current sampling time is inconsistent with the cathodic protection operating condition at the previous sampling time, obtaining the PID control parameters before and after the switch based on the updated cathodic protection control reference parameters, and interpolating the PID control parameters before and after the switch according to a preset sliding time window to obtain the target control parameters.

[0011] In conjunction with the first aspect mentioned above, in one possible implementation, the target control parameter is obtained by interpolating the PID control parameters before and after the switch according to a preset sliding time window. This includes: when a switch in the current cathodic protection operating condition is detected, establishing a sliding time window with a preset window length, and using the PID control parameters corresponding to the start time of the window as the PID control parameters before the switch, and using the PID control parameters corresponding to the current cathodic protection operating condition as the PID control parameters after the switch; determining a dynamic weighting factor based on the ratio of the number of steps in the sliding time window at the current sampling time to the preset window length; performing weighted calculations on the PID control parameters before and after the switch according to the dynamic weighting factor to obtain the target control parameter corresponding to the current sampling time; and determining the PID control parameter after the switch as the target control parameter when the sliding time window ends.

[0012] In conjunction with the first aspect mentioned above, in one possible implementation, the cathodic protection control quantity is determined based on the protection potential data, target control parameters, and a preset control algorithm. This includes: calculating the potential deviation based on the protection potential data and the updated protection potential reference value; inputting the potential deviation and the proportional, integral, and derivative parameters in the target control parameters into an incremental PID control model to calculate the control voltage increment; and determining the cathodic protection control quantity at the current moment based on the control voltage increment at the current moment and the control voltage at the previous moment.

[0013] Secondly, a dual-timescale offshore wind turbine cathodic protection control system is provided, applicable to any method in the first aspect. The system includes: an environment and state perception module for acquiring protection potential data, environmental monitoring data, and cathodic protection power supply operation data of the offshore wind turbine foundation; wherein, the environmental monitoring data includes tide level data, seawater flow velocity data, and seawater temperature data, and the cathodic protection power supply operation data includes the output voltage and output current of the cathodic protection power supply; a dual-timescale main control unit, employing an embedded Linux system and configured with a multi-task concurrent processing mechanism, for performing short-timescale operating condition identification based on protection potential data, tide level data, and seawater flow velocity data to determine the current cathodic protection operating condition; determining the equivalent polarization impedance of the wind turbine foundation based on seawater temperature data and the output voltage and output current of the cathodic protection power supply, and determining the equivalent polarization impedance of the wind turbine foundation based on seawater temperature data and the equivalent polarization impedance of the cathodic protection power supply, and determining the equivalent polarization impedance of the wind turbine foundation based on seawater temperature data and the equivalent polarization impedance of the cathodic protection power supply. The system updates the cathodic protection control reference parameters based on the effective polarization impedance; it calls the corresponding control parameters according to the current cathodic protection operating conditions and generates target control parameters by combining the updated cathodic protection control reference parameters; the power execution unit, including the IGBT full-bridge inverter circuit and drive circuit, is used to determine the cathodic protection control quantity based on the protection potential data, target control parameters and preset control algorithm, and adjust the cathodic protection power supply output according to the cathodic protection control quantity; the cathodic protection power supply output terminal is used to apply the adjusted cathodic protection power supply output DC protection current to the auxiliary anode of the offshore wind turbine foundation to form a cathodic protection electric field in the seawater environment; the remote monitoring module communicates with the dual time scale main control unit through industrial Ethernet or CAN bus, and is used to upload system operating status, environmental monitoring data, protection potential data and PID control parameters to the wind farm central control center.

[0014] This application provides a cathodic protection control method and system for offshore wind turbines based on dual time scales. By constructing a parallel architecture of short-time-scale operating condition identification and long-time-scale reference parameter updating, the system can simultaneously cope with short-period high-frequency disturbances such as tides and waves, as well as long-period reference drifts such as water temperature and coating aging. Short-time-scale operating condition identification utilizes tidal level fluctuation rate and seawater flow velocity data to determine the current operating condition in real time and dynamically call the corresponding PID control parameters, effectively overcoming the slow response and overshoot oscillation problems of fixed-parameter controllers in large-hysteresis nonlinear environments. Long-time-scale reference parameter updating uses seawater temperature trends and equivalent polarization impedance changes to periodically correct the protection potential reference value and PID control parameters, enabling the system to adaptively adjust the output according to service life and seasonal changes, avoiding energy waste caused by excessive current and corrosion risks due to insufficient protection. During operating condition switching, a preset sliding time window is used to interpolate the control parameters before and after the switch, ensuring a continuous and smooth output of the control voltage, eliminating the electrical impact of parameter abrupt changes on the IGBT power module and the polarization film on the foundation surface, extending equipment life and improving the stability of the anti-corrosion effect.

[0015] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0016] Figure 1 A system architecture diagram of a dual-time-scale offshore wind turbine cathodic protection control system provided for embodiments of this application; Figure 2 A flowchart illustrating a dual-time-scale cathodic protection control method for offshore wind turbines provided in this application embodiment. Figure 1 ; Figure 3 A flowchart illustrating a dual-time-scale cathodic protection control method for offshore wind turbines provided in this application embodiment. Figure 2 ; Figure 4 This is a schematic diagram of short-cycle high-frequency dynamic operating condition state transition provided in an embodiment of this application; Figure 5 A flowchart illustrating a dual-time-scale cathodic protection control method for offshore wind turbines provided in this application embodiment. Figure 3 ; Figure 6 A flowchart illustrating a dual-time-scale cathodic protection control method for offshore wind turbines provided in this application embodiment. Figure 4 . Detailed Implementation

[0017] In the description of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. The "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, "at least one" means one or more, and "multiple" means two or more. The terms "first," "second," etc., do not limit the quantity or order of execution, and "first," "second," etc., do not necessarily imply differences.

[0018] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0019] The cathodic protection control method for offshore wind turbines based on dual time scales provided in this application can be applied to, for example... Figure 1 In the offshore wind turbine cathodic protection control system based on dual time scales shown, such as Figure 1 As shown, the system includes: an environment and state perception module 101, used to acquire protection potential data, environmental monitoring data, and cathodic protection power supply operation data of the offshore wind turbine foundation; wherein, the environmental monitoring data includes tide level data, seawater flow velocity data, and seawater temperature data, and the cathodic protection power supply operation data includes the output voltage and output current of the cathodic protection power supply; a dual-timescale main control unit 102, which adopts an embedded Linux system and is configured with a multi-task concurrent processing mechanism, used to identify short-timescale operating conditions based on protection potential data, tide level data, and seawater flow velocity data, and determine the current cathodic protection operating condition; determine the equivalent polarization impedance of the wind turbine foundation based on seawater temperature data and the output voltage and output current of the cathodic protection power supply, and update the cathodic protection control reference parameters according to the seawater temperature data and the equivalent polarization impedance; and according to the current The system calls the corresponding control parameters for the pre-cathode protection operation condition and generates target control parameters by combining them with the updated cathodic protection control reference parameters; the power execution unit 103, including an IGBT full-bridge inverter circuit and a drive circuit, is used to determine the cathodic protection control quantity based on the protection potential data, the target control parameters, and the preset control algorithm, and adjust the cathodic protection power supply output according to the cathodic protection control quantity; the cathodic protection power supply output terminal 104 is used to apply the adjusted cathodic protection power supply output DC protection current to the auxiliary anode of the offshore wind turbine foundation to form a cathodic protection electric field in the seawater environment; the remote monitoring module 105 is connected to the dual time-scale main control unit via industrial Ethernet or CAN bus to upload system operating status, environmental monitoring data, protection potential data, and PID control parameters to the wind farm central control center.

[0020] To address the technical problem that existing technologies cannot simultaneously achieve rapid response to short-period high-frequency environmental disturbances and long-period reference drift adjustment, this application provides a cathodic protection control method for offshore wind turbines based on dual time scales. Figure 2 A flowchart illustrating the cathodic protection control method for offshore wind turbines based on dual time scales provided in this application embodiment. Figure 1 ,like Figure 2 As shown, it includes: S201. Obtain the protection potential data, environmental monitoring data, and cathodic protection power supply operation data of the offshore wind turbine foundation.

[0021] The environmental monitoring data includes tide level data, seawater flow velocity data, and seawater temperature data. The cathodic protection power supply operation data includes the output voltage and output current of the cathodic protection power supply. The protection potential data refers to the electrochemical potential value of the wind turbine foundation steel structure relative to the seawater medium, collected in real time through a reference electrode, used to assess whether the foundation is currently under effective cathodic protection. The tide level data in the environmental monitoring data reflects the change in the submerged area of ​​the wind turbine foundation with the rise and fall of the tides; the seawater flow velocity data characterizes the scouring intensity of the ocean current on the foundation surface; and the seawater temperature data is used to assess the impact of ambient temperature on the electrochemical reaction rate. The output voltage and output current in the cathodic protection power supply operation data are synchronously collected by the internal sampling circuit of the potentiostat and used to calculate the long-term trend of the equivalent polarization impedance of the foundation surface.

[0022] In one possible implementation, the environment and condition sensing module isolates, amplifies, and converts the analog signals output from each sensor to digital, then transmits them uniformly to the dual-timescale main control unit via an SPI or I2C bus interface. The main control unit internally runs a data acquisition scheduling thread that synchronously latches the multi-channel data at a fixed sampling period, ensuring that the potential, tide, flow velocity, and temperature data at the same sampling moment have strict time alignment, providing a reliable data foundation for subsequent condition identification and benchmark updates.

[0023] It should be noted that the data acquired in this step differs from existing single reference electrode potential acquisition schemes in terms of type and source. By introducing multi-dimensional environmental variables such as tide level, current velocity, and temperature, the subsequent control logic can perceive short-period dynamic disturbances and long-period reference drifts in the marine environment, thereby providing necessary information support for parallel processing on dual time scales.

[0024] As an example, in a cathodic protection system actually deployed on a monopile foundation of an offshore wind farm, the sampling period can be set to 1 second. The reference electrode can be a high-purity zinc reference electrode, a silver / silver chloride reference electrode, or other reference electrodes suitable for seawater environments. The tide level sensor can be an immersion-type level transmitter, the flow velocity sensor can be an acoustic Doppler current profiler, and the temperature sensor can be set independently or integrated into the flow velocity sensor probe. The signals from each sensor are fed into the environmental and status sensing module via a 4-20mA current loop, an RS485 digital interface, or other industrial communication interfaces. After analog-to-digital conversion, filtering, and normalization, the signals are sent to the dual-timescale main control unit.

[0025] S202. Based on protection potential data, tide level data, and seawater flow velocity data, short-time scale operating condition identification is performed to determine the current cathodic protection operating condition.

[0026] Among them, short-timescale operating condition identification refers to the real-time determination of instantaneous changes in the marine environment at a time granularity of seconds to minutes, classifying the current protection condition of the wind turbine foundation into different operating states. Cathodic protection operating conditions are discrete states divided to adapt to different levels of marine environmental disturbance. Under each state, the system calls a set of control parameters that match it to optimize the response speed and steady-state accuracy of the protection potential.

[0027] In one possible implementation, a short-cycle real-time control thread is initiated within the dual-timescale master control unit. This thread runs in a second-level loop, acquiring the latest protection potential data, tide level data, and seawater flow velocity data in each loop, calculating the tide level fluctuation rate, and inputting the tide level fluctuation rate and flow velocity data into a pre-constructed operating condition state machine. Based on the flow velocity threshold and hysteresis judgment rules, the operating condition state machine completes the state transition judgment within milliseconds and outputs the cathodic protection operating condition label corresponding to the current sampling time.

[0028] It is important to note that the core value of short-timescale condition identification lies in addressing the problem that existing fixed-parameter controllers cannot distinguish between different levels of ocean disturbance. When the tide is stable and the current velocity is low, the system can use more conservative control parameters to ensure steady-state accuracy; during rapid tides or high current velocities, the system needs to switch to more aggressive parameters to accelerate the polarization response. Without the condition identification step, the system can only use a set of compromise parameters to handle all scenarios, making it difficult to reconcile the contradiction of easy overshoot during stable periods and slow response during violent periods.

[0029] Based on the above steps, by identifying the operating conditions of protection potential data, tide level data, and seawater flow velocity data on a short timescale with a second-level cycle, the system can perceive the short-period dynamic changes of the marine environment in real time and actively determine the current cathodic protection operating conditions.

[0030] S203. Determine the equivalent polarization impedance of the wind turbine foundation based on seawater temperature data and the output voltage and current of the cathodic protection power supply, and update the cathodic protection control reference parameters according to the seawater temperature data and the equivalent polarization impedance.

[0031] Among them, the cathodic protection control reference parameters refer to a set of reference values ​​preset by the system under standard environmental conditions, including the protection potential reference value and the corresponding reference PID control parameters, which serve as the basic reference for calling parameters under various operating conditions. The equivalent polarization impedance is a characterization of the electrochemical impedance of the base surface calculated based on the ratio of steady-state output voltage to output current. Its changing trend reflects the comprehensive influence of long-term factors such as coating aging and marine organism adhesion on the base surface condition.

[0032] In one possible implementation, a long-cycle adaptive evaluation background thread is initiated within the dual-timescale main control unit. This thread runs independently with a daily cycle, forming a parallel architecture with the short-cycle real-time control thread of S202. The two threads interact via shared memory. At the end of each evaluation cycle, the long-cycle thread calculates the average of the seawater temperature data collected during that cycle and calculates the equivalent polarization impedance based on the steady-state averages of the output voltage and current. It then corrects the cathodic protection control reference parameters from the previous cycle using the temperature drift coefficient and impedance aging coefficient, writing the corrected reference parameters to a designated address in the shared memory. The short-cycle thread reads the latest reference parameters from this address during the next operating condition call, completing the closed loop of reference update.

[0033] It should be noted that S202 and S203 are parallel processes, independent of each other in terms of time scale and execution logic. The short-cycle thread focuses on real-time condition perception and rapid response at the second level, while the long-cycle thread focuses on daily baseline parameter trend correction. The advantage of this architecture is that long-cycle baseline updates do not block or interfere with short-cycle real-time control, while short-cycle control can also benefit from the results of long-cycle baseline updates in a timely manner. The two achieve asynchronous and decoupled data interaction through shared memory.

[0034] Based on the above steps, the baseline parameters are adaptively updated through a long-term evaluation thread, which compensates for the slow effects of seasonal temperature differences and coating aging on the basic electrochemical properties. Together with S202, a dual-time-scale parallel processing architecture is formed, enabling the system to simultaneously take into account short-cycle perturbation response and long-cycle baseline drift correction.

[0035] S204. Based on the current cathodic protection operating conditions, call the corresponding control parameters and generate target control parameters by combining them with the updated cathodic protection control reference parameters.

[0036] The target control parameters refer to the complete set of parameters that are ultimately input into the incremental PID control model for control quantity calculation, including the protection potential reference value, proportional parameters, integral parameters, and derivative parameters. The current cathodic protection operating condition is determined by the short-timescale operating condition identification result of S202, and the updated cathodic protection control reference parameters are provided by the long-cycle adaptive evaluation result of S203. The combination of the two ensures that the target control parameters reflect both the characteristics of short-cycle environmental disturbances and include long-cycle reference drift compensation.

[0037] In one possible implementation, the dual-timescale main control unit maintains a preset operating condition parameter library. This library stores the adjustment amounts or adjustment coefficients of the PID control parameters relative to the reference parameters for each cathodic protection operating condition. During execution S204, the short-cycle thread indexes the corresponding adjustment amount from the parameter library based on the operating condition label determined in S202, and performs a combination operation with the updated reference PID control parameters read from shared memory to obtain the proportional, integral, and derivative parameters in the target control parameters. Simultaneously, the updated protection potential reference value is used as the protection potential reference value in the target control parameters. If the operating condition at the current sampling time is consistent with the previous time, the combined result is directly output; if an operating condition switch occurs, a smooth transition process is initiated.

[0038] It should be noted that this step decouples the calling of operating conditions from the updating of the baseline, so that when the operating conditions change in a short period, only the offset relative to the baseline needs to be adjusted, while when the baseline drifts in a long period, only the baseline value itself needs to be updated. The adjustments of the two time scales do not interfere with each other, thus avoiding the complexity of parameter maintenance.

[0039] Based on the above steps, by combining the short-timescale operating condition identification results with the long-timescale benchmark update results, the generated target control parameters simultaneously adapt to the current environmental disturbance level and basic electrochemical state, so that the response speed and protection accuracy of the system control output remain optimal at different time scales.

[0040] S205. Determine the cathodic protection control quantity based on the protection potential data, target control parameters, and preset control algorithm, and adjust the cathodic protection power supply output according to the cathodic protection control quantity.

[0041] The cathodic protection control quantity refers to the voltage or current command value ultimately applied to the power execution unit, used to adjust the magnitude of the DC protection current output by the auxiliary anode to the seawater environment. The preset control algorithm is an incremental PID control model, which uses the target control parameters and potential deviation to calculate the control voltage increment in real time and accumulates it to obtain the absolute control quantity at the current moment.

[0042] In one possible implementation, the potential deviation is calculated based on the protection potential data and the updated protection potential reference value; the potential deviation, along with the proportional, integral, and derivative parameters in the target control parameters, are input into the incremental PID control model to calculate the control voltage increment; and the cathodic protection control quantity at the current moment is determined based on the control voltage increment at the current moment and the control voltage at the previous moment.

[0043] It should be noted that incremental PID control models have inherent advantages over positional PID control models in terms of resistance to integral saturation and shock-free switching. Incremental PID only outputs the change in the control quantity. When switching operating conditions or updating the reference parameters, even if the internal parameters change, the control quantity itself will not produce a step jump, but will smoothly transition to the new steady-state value. This provides a basic guarantee for the smooth transition of parameters during subsequent operating condition changes.

[0044] Based on the above steps, by combining the target control parameters with the incremental PID control algorithm, the protection potential deviation is transformed into a continuous cathodic protection control output, realizing a complete closed-loop control link from environmental perception, operating condition identification, parameter update to power execution, ensuring that the wind turbine foundation can maintain a stable protection potential under various marine operating conditions.

[0045] This embodiment constructs a parallel processing architecture for short-term operating condition identification and long-term reference parameter updates, enabling the system to simultaneously address short-period high-frequency disturbances such as tides and waves, and long-period reference drifts such as seawater temperature and coating aging, within the same control framework. Compared to existing fixed-parameter PID control strategies, this embodiment's method does not adapt to all marine environmental scenarios with a set of compromise parameters. Instead, it dynamically calls matching control parameters based on the real-time identified operating conditions, while adaptively correcting the reference value based on long-term trends. This effectively alleviates the contradiction between control overshoot during stable periods and slow response during severe periods, achieving precise closed-loop control of the protection potential throughout its entire lifecycle.

[0046] In one possible implementation of the embodiments of this application, combined with Figure 2 ,like Figure 3 As shown, the above S202 can be specifically implemented through the following S301, S302 and S303, which are explained in detail below: S301. Calculate the tidal level variation rate based on the tidal level data from multiple consecutive sampling times, and input the tidal level variation rate and seawater flow velocity data into the operating condition state machine.

[0047] The tidal level fluctuation rate refers to the measure of the tidal level change within a unit sampling period, used to characterize the speed of tidal rise and fall. The operating condition state machine is a finite state machine model pre-set in the dual-time-scale master control unit, which internally defines multiple cathodic protection operating condition states and the judgment rules for transition between states based on input variables.

[0048] In one possible implementation, the dual-timescale master control unit obtains the current sampling time from the environment and state awareness module when executing the short-cycle real-time control thread. and the previous sampling time Tide level data and And based on the known sampling period Calculate the rate of change of tide level This rate of change is a scalar; its absolute value is used to eliminate the interference of the directional difference between high and low tides on the determination of operating conditions. After the calculation is completed, the main control unit will... and current seawater current speed data As an input variable, it is passed to the decision function of the operating condition state machine.

[0049] It's important to note that the operating condition state machine differs from a simple threshold comparison. Internally, it maintains the current operating condition state variable and updates the state based on input variables and preset rules, rather than making independent judgments each time. This state transition mechanism with memory enables the system to make continuous and stable judgments on current environmental changes based on historical states, avoiding disordered jumps in operating condition labels under sensor noise or minor water wave disturbances.

[0050] Based on the above steps, by continuously calculating the tidal level variation rate and inputting the variation rate and flow velocity data into the operating condition state machine, the operating condition identification process incorporates environmental characteristics of two dimensions: tidal level change trend and seawater scouring intensity. Compared with simple threshold judgment that relies solely on data from a single sensor, this approach can more comprehensively reflect the combined impact of the marine environment on the cathodic protection status of the wind turbine foundation.

[0051] S302. The operating condition machine compares the seawater flow velocity data with the preset flow velocity threshold. When the seawater flow velocity data is greater than the preset flow velocity threshold, the current cathodic protection operating condition is determined to be a severe sea condition.

[0052] The preset flow velocity threshold is used to characterize the judgment boundary of severe sea conditions. When the seawater flow velocity exceeds this threshold, it indicates that the surface of the offshore wind turbine foundation is subjected to strong fluid scouring, which affects the stable establishment of the polarization film on the steel structure surface. The cathodic protection system needs to enter the enhanced protection response mode corresponding to severe sea conditions.

[0053] In one possible implementation, the state machine first checks the seawater flow velocity data when making a decision. Is it greater than the preset flow rate threshold? .when Upon successful execution, regardless of the current state of the state machine, the current cathodic protection operating condition will be immediately and forcibly transitioned to a severe sea state, denoted as S3. This flow velocity determination has the highest priority in the state machine logic; that is, under high flow velocity conditions, the magnitude of the tidal level fluctuation rate no longer affects the operating condition determination result, and the system will uniformly lock into state S3. A preset flow velocity threshold is set. Calibration can be performed based on the annual hydrological data of the sea area where the wind turbine foundation is located and the hydrodynamic simulation results of the foundation structure. For example, in the application of monopile foundations in a certain sea area, It can be set to 2 m / s. When the flow rate drops back to... Only after the condition has been maintained for a certain number of times can the state machine exit from S3 and re-determine whether to enter S1 or S2 based on the tide level change rate.

[0054] It should be noted that the flow velocity determination is set as a high priority because strong currents in severe sea conditions can significantly weaken the cathodic protection effect. Under strong currents, the risk of disturbance or even local damage to the polarization film on the base surface increases. If the system still uses conventional control parameters under steady-state or fluctuating tidal conditions, the polarization establishment rate may lag behind the polarization film loss rate, causing the base potential to deviate from the preset protection range. Therefore, this step enables the system to promptly enter enhanced protection control mode when a high flow velocity threat is detected. Under the premise of meeting the potentiostat output constraints and the protection potential safety boundary, this improves the protection response speed and reduces the time window of insufficient protection.

[0055] Based on the above steps, by assigning the highest priority to flow velocity determination in the operating state machine, the system can identify and switch to the corresponding protection mode as soon as it encounters severe sea conditions, thus solving the problem of slow response of existing fixed parameter controllers under strong current scouring and improving the protection reliability in extreme marine environments.

[0056] S303. When the seawater flow velocity data is not greater than the preset flow velocity threshold, the operating condition state machine determines the current cathodic protection operating condition as either tidal steady-state or tidal variable condition based on the tidal level variation rate and the preset hysteresis judgment rule.

[0057] The preset hysteresis judgment rule refers to setting two different thresholds for tidal level fluctuation rates, making the state transition conditions related to the current state. This creates a state-maintaining interval in the critical region, preventing frequent switching of operating conditions due to minor fluctuations in tidal level data. The steady-state tidal condition corresponds to a stage where the tidal level is stable or changes slowly, and the submerged area of ​​the foundation is relatively stable. The fluctuating tidal condition corresponds to emergency high tide or rapid low tide stages, where the submerged area of ​​the foundation changes rapidly, and the electrochemical interface state exhibits strong time-varying characteristics.

[0058] In one possible implementation, a first tidal fluctuation rate threshold and a second tidal fluctuation rate threshold are set, with the first threshold being greater than the second threshold. When the current cathodic protection operating condition is a tidal steady-state condition and the tidal fluctuation rate is greater than the first threshold, the current cathodic protection operating condition is determined to be a tidal fluctuation condition. When the current cathodic protection operating condition is a tidal fluctuation condition and the tidal fluctuation rate is less than the second threshold, the current cathodic protection operating condition is determined to be a tidal steady-state condition. When the tidal fluctuation rate is greater than or equal to the second threshold and less than or equal to the first threshold, the current cathodic protection operating condition remains unchanged.

[0059] It should be noted that, Figure 4 This is a schematic diagram of short-cycle high-frequency dynamic operating condition state transitions provided in an embodiment of this application, such as... Figure 4 As shown, to prevent sensor noise or minor water wave disturbances from causing frequent oscillations and switching of the state machine at critical points, this application introduces a hysteresis comparison mechanism into the operating state machine, setting high and low trigger thresholds for the tidal level fluctuation rate as follows: and ,in and safety thresholds for current speeds in severe sea conditions. The system defines three core short-cycle dynamic operating conditions: (Tidal steady-state operating condition) (Tidal variation conditions) (Severe sea state condition). The logic of its state transition is as follows: Entering severe sea state ( The highest priority determination: regardless of the current state, if the following conditions are met. The state machine immediately forces a jump and locks to... This state triggers the system's disturbance rejection limit output mode. The system is in... and Based on the rate of change of tide level Switch by absolute value: if the current state is ,when This indicates that the tide is rising and falling rapidly, the flooded area is changing drastically, and the state machine jumps to [a specific state]. If the current state is ,when When this occurs, it indicates that the tide is stabilizing and the state machine returns to its previous state. .when In During the interval, the state machine retains the state of the previous moment.

[0060] Based on the above steps, by introducing a hysteresis judgment rule with high and low dual thresholds between the steady-state tidal condition and the tidal fluctuation condition, the condition state machine is only triggered to transition when there is a clear and continuous substantial change in the trend of tidal level change. This effectively suppresses the condition flickering phenomenon caused by sensor noise or natural tidal fluctuations in the critical region, and improves the stability and anti-interference ability of condition identification on a short time scale.

[0061] In one possible implementation of the embodiments of this application, combined with Figure 2 ,like Figure 5 As shown, the above S203 can be specifically implemented through the following S501 to S504, which are explained in detail below: S501. Statistically process the seawater temperature data collected within the preset long-term evaluation period to obtain the average seawater temperature.

[0062] The preset long-term evaluation period refers to the running period of the long-term adaptive evaluation thread, which is much longer than the sampling period of the short-term real-time control thread, and is usually set to the level of days, such as 24 hours. The average seawater temperature is a representative value obtained by statistically averaging the seawater temperature data at all valid sampling times within the evaluation period. It is used to suppress the interference of sensor instantaneous noise and daytime temperature fluctuations on the update of the reference parameters.

[0063] In one possible implementation, the long-cycle thread of the dual-timescale master control unit is initialized at the beginning of each evaluation cycle. During the cycle, it continuously receives seawater temperature data collected by the environment and state awareness module and stores it in a thread-private circular buffer. When the evaluation cycle ends, the thread reads all temperature samples in the buffer, removes outliers exceeding a preset reasonable range (e.g., -5℃ to 45℃), and then performs an arithmetic average on the remaining valid data to obtain the average seawater temperature. In other possible implementations, statistical processing can also employ weighted averaging, median filtering, or moving averages, with the aim of reducing the impact of instantaneous noise and reflecting the overall temperature level within the cycle.

[0064] S502. Determine the equivalent polarization impedance of the fan foundation based on the output voltage and output current of the cathodic protection power supply.

[0065] The equivalent polarization impedance refers to the ratio of the output voltage to the output current of the potentiostat under steady-state output conditions. This ratio comprehensively reflects the influence of factors such as the coating impedance on the wind turbine foundation surface, the degree of marine organism adhesion, and the conductivity of seawater on the electrochemical circuit. In long-term benchmark drift assessment, the changing trend of the equivalent polarization impedance directly reflects the cumulative effect of slowly changing factors such as coating aging and peeling, and marine organism adhesion.

[0066] In one possible implementation, the long-cycle thread of the dual-timescale master control unit synchronously acquires multiple steady-state sample values ​​of the output voltage and output current of the cathodic protection power supply within the same evaluation cycle of S501. To avoid interference from transient processes, only sampling points where the fluctuation amplitude of both output voltage and output current is lower than a preset steady-state judgment threshold (e.g., voltage fluctuation less than 2% of the rated value and current fluctuation less than 3% of the rated value) are selected as valid steady-state samples. The steady-state mean values ​​of the output voltage and output current are calculated separately, and then divided to obtain the equivalent polarization impedance. When the number of valid steady-state samples is lower than the preset minimum number of samples, it indicates that the system may be in a state of drastic dynamic adjustment for a long period of time during this cycle, resulting in insufficient reliability. The long-cycle thread abandons the update of the reference parameters for this round, uses the reference parameters from the previous cycle, and generates an alarm flag.

[0067] It should be noted that the ratio calculation uses the steady-state average voltage and current, rather than instantaneous values, to eliminate the interference of instantaneous changes in voltage and current during short-cycle dynamic adjustment on impedance estimation. The potentiostat's output power adjusts rapidly in response to tidal changes or severe sea conditions. The instantaneous ratio of voltage and current cannot accurately reflect the electrochemical impedance characteristics of the base surface. Only steady-state statistics over a certain time window can effectively extract the gradual trends caused by coating aging and marine organism adhesion.

[0068] Based on the above steps, the equivalent polarization impedance is calculated by using the average value of steady-state output voltage and output current, eliminating transient interference caused by short-cycle dynamic adjustment, so that the equivalent polarization impedance can accurately characterize the comprehensive influence of long-cycle factors such as coating aging and marine organism adhesion on the electrochemical properties of the base surface.

[0069] S503. Determine the temperature drift coefficient based on the average seawater temperature, and determine the impedance aging coefficient based on the equivalent polarization impedance.

[0070] Among them, the temperature drift coefficient is a correction factor used to quantify the impact of seawater temperature changes on the equilibrium potential of electrochemical reactions. Its physical basis lies in the exponential relationship between the exchange current density of the electrochemical reaction and temperature; increased temperature accelerates the electrode reaction kinetics, thereby altering the actual required value of the protection potential. The impedance aging coefficient is a correction factor used to quantify the impact of coating aging and marine organism adhesion on the dynamic characteristics of the system control loop. Its physical basis lies in the fact that an increase or decrease in coating impedance directly alters the electrical time constant of the protected system, thus affecting the optimal gain parameters of the PID control loop.

[0071] In one possible implementation, the average seawater temperature is compared with a preset standard ambient temperature to determine the temperature deviation; the temperature drift coefficient is calculated based on the temperature deviation and a preset temperature correction model; the equivalent polarization impedance is compared with a preset standard polarization impedance to determine the impedance deviation; and the impedance aging coefficient is calculated based on the impedance deviation and a preset impedance correction model.

[0072] Furthermore, the preset standard ambient temperature is typically 20°C, representing a baseline state where the wind turbine foundation's anti-corrosion coating is intact, there is no marine organism attachment, and the seawater is at standard temperature conditions. The preset standard polarization impedance refers to the initial value of the equivalent polarization impedance of the foundation surface measured at the standard ambient temperature, with the coating intact and no marine organism attachment. This value can be written into non-volatile memory after offline measurement and calibration during the system's factory commissioning phase.

[0073] The pre-defined temperature correction model can be constructed based on a simplified form of the Arrhenius equation. In a specific simplified model, the temperature drift coefficient... Represented as ,in, The average seawater temperature, Standard ambient temperature, This is a temperature correction factor, the value of which can be determined based on electrochemical experimental data of the steel used in the wind turbine foundation in a seawater environment, for example... The value can range from 0.005 / ℃ to 0.02 / ℃. In other feasible implementations, the temperature correction model can also be obtained using a lookup table method.

[0074] Furthermore, the preset impedance correction model will convert the equivalent polarization impedance With preset standard polarization impedance The ratio or a function thereof is used as the impedance aging coefficient. , ,in, This is an impedance aging correction factor, which can be calibrated based on experimental data of coating degradation rates. When When the value increases, it usually means that the coating's insulation performance has decreased or that marine organisms have adhered, leading to an increase in surface impedance. The system loop gain needs to be increased accordingly to maintain the effective polarization current. A decrease in gain may indicate localized damage to the coating, exposing a fresh metal surface. In such cases, the loop gain needs to be reduced accordingly to prevent overprotection.

[0075] It should be noted that the temperature drift coefficient and impedance aging coefficient are solved independently in this embodiment, corresponding to different physical mechanisms and correction targets. The change in the temperature drift coefficient is caused by the drift of electrochemical reaction thermodynamic and kinetic parameters due to changes in seawater temperature, mainly affecting the protection potential requirement of the protected metal; the change in the impedance aging coefficient is caused by changes in surface impedance due to coating aging and marine organism adhesion, mainly affecting the dynamic transmission characteristics of the potentiostat control loop. Calculating these two types of coefficients separately provides a reasonable physical basis for correcting different types of reference parameters in S504.

[0076] S504. Based on the temperature drift coefficient and impedance aging coefficient, the preset cathodic protection control reference parameters are corrected to obtain the updated cathodic protection control reference parameters.

[0077] In one possible implementation, preset cathodic protection control reference parameters under standard conditions are obtained. These reference parameters include a protection potential reference value and corresponding PID control parameters. The protection potential reference value is compensated according to the temperature drift coefficient to obtain an updated protection potential reference value. The PID control parameters are compensated according to the impedance aging coefficient to obtain updated PID control parameters. The updated protection potential reference value and the updated PID control parameters are used as the updated cathodic protection control reference parameters.

[0078] As an example, in this embodiment, the cathodic protection control reference parameters are explicitly divided into two independent parts: the first part is the protection potential reference value, which is the reference target for potential deviation calculation in the incremental PID control model, determining the electrochemical protection level at which the system maintains the base potential; the second part is the PID control parameters, including proportional parameters. Integral parameters and differential parameters These factors together determine the dynamic response characteristics of the potentiostat control loop, namely the speed, accuracy, and stability from detecting the potential deviation to adjusting the output current.

[0079] Furthermore, for the correction of the protection potential reference value, only the temperature drift coefficient is used. Compensation is performed without introducing an impedance aging factor. The reason is that the reference value for the protection potential is mainly used to characterize the target protection potential that the protected steel structure should maintain in the current seawater environment, and its changes are mainly related to changes in electrochemical reaction conditions caused by seawater temperature; while the aging state of the coating and the degree of marine organism adhesion mainly affect the equivalent impedance of the steel structure surface and the dynamic response characteristics of the cathodic protection circuit, therefore, they are not considered as direct correction factors for the reference value of the protection potential in this step. The specific compensation method can be direct multiplication, i.e. ,in, This is the updated protection potential reference value. The reference value for the protection potential calibrated under standard conditions. It can be a temperature drift coefficient; or it can be a lookup correction based on the temperature-potential mapping relationship.

[0080] Furthermore, for the correction of PID control parameters, only the impedance aging coefficient is used. Compensation is performed without introducing a temperature drift coefficient. The reason is that PID control parameters are mainly used to adjust the response speed, control accuracy, and stability of the potentiostat control loop, and their reasonable values ​​are mainly related to the electrical time constant of the controlled object; the electrical time constant is determined by the equivalent impedance of the base surface and the double-layer capacitance. As the coating ages or the degree of marine organism adhesion increases, the equivalent impedance of the base surface changes, thereby altering the dynamic characteristics of the cathodic protection circuit. Therefore, it is necessary to adjust the parameters according to the impedance aging coefficient. Compensate the PID control parameters. Specific compensation methods could include... , , ,in, , and These are the updated proportional parameters, integral parameters, and derivative parameters, respectively. , and These are the proportional, integral, and derivative parameters calibrated under standard conditions.

[0081] Based on the above steps, by dividing the cathodic protection control reference parameters into two independent parts—the protection potential reference value and the PID control parameters—and using temperature drift coefficient and impedance aging coefficient for targeted separation and correction, the protection potential setting can independently respond to seasonal changes in seawater temperature, while the dynamic parameters of the control loop can independently respond to the long-term trends of coating aging and marine organism attachment. This avoids the defect of the system being unable to simultaneously optimize protection accuracy and control quality due to the mutual coupling and cancellation of drift factors of two different physical mechanisms under a unified correction method.

[0082] In one possible implementation of the embodiments of this application, combined with Figure 2 ,like Figure 6 As shown, the above S204 can be specifically implemented through the following S601 to S604, which are explained in detail below: S601. Based on the current cathodic protection operating conditions, retrieve the PID control parameters corresponding to the current cathodic protection operating conditions from the preset operating condition parameter library.

[0083] The preset operating condition parameter library is a mapping table pre-stored in the non-volatile memory of the dual-time-scale main control unit. This table establishes the correspondence between cathodic protection operating condition labels and PID control parameter adjustments. Each operating condition label corresponds to a set of proportional, integral, and derivative parameter adjustments calibrated through offline simulation and field debugging. These adjustments can be gain coefficients or biases relative to the baseline PID control parameters, and their specific form depends on the parameter organization strategy selected during the system configuration phase.

[0084] In one possible implementation, the preset operating condition parameter library is stored as a structure array in the Flash memory of the dual-timescale main control unit. Each array element contains an operating condition label field and three floating-point adjustment fields. When the short-cycle real-time control thread executes S601, it uses the current cathodic protection operating condition determined in S202 as an index to search for a matching operating condition label in the array and reads the corresponding PID control parameter adjustment. If the lookup is successful, the adjustment is read into a thread-local variable; if the operating condition label is not found in the table due to a system anomaly, the preset default adjustment is used, and an alarm flag is reported to the remote monitoring module. In addition to the structure array method, the preset operating condition parameter library can also be organized as key-value pairs, hash tables, or database files.

[0085] Based on the above steps, by calling the corresponding PID control parameter adjustment amount from the preset operating condition parameter library according to the current operating condition label, the short cycle thread can quickly obtain control parameters that match the current level of environmental disturbance, providing a basic input for subsequent parameter combination and smooth switching.

[0086] S602. Determine whether the cathodic protection operating conditions at the current sampling time are consistent with the cathodic protection operating conditions at the previous sampling time.

[0087] The operating condition comparison mechanism is the trigger judgment link for smooth parameter switching. The short-cycle real-time control thread of the dual-timescale main control unit maintains an operating condition history variable in memory to record the cathodic protection operating condition tag at the previous sampling time.

[0088] In one possible implementation, the operating condition history variable is defined as a global static enumeration variable, which is assigned the value of the tidal steady-state operating condition during system initialization. In step S602 of each sampling period, a short-cycle thread executes a comparison function that compares the current operating condition enumeration value with the operating condition history variable value, returning a Boolean value as the criterion for whether an operating condition switch has occurred. After the comparison is complete, the thread writes the current operating condition enumeration value to the operating condition history variable, overwriting the old value, preparing for the comparison in the next sampling period.

[0089] It should be noted that the operating condition comparison mechanism is a logical switch that ensures the smooth switching algorithm is triggered only when necessary. Without the comparison step, the system will be unable to distinguish whether it is currently in a steady-state operation phase or a switching transition phase, and thus will be unable to correctly select the direct combination path or the interpolation transition path.

[0090] Based on the above steps, by comparing operating conditions in each sampling period, the system can accurately identify the time when the operating condition switch occurs, providing a reliable basis for subsequent path selection, avoiding the extra computational overhead caused by the activation of the smooth switching algorithm when it is not necessary, and also ensuring the timely triggering of smooth transition when necessary.

[0091] S603. When the cathodic protection operating condition at the current sampling time is consistent with the cathodic protection operating condition at the previous sampling time, the called PID control parameters will be combined with the updated cathodic protection control reference parameters to generate target control parameters.

[0092] The target control parameters are the complete set of parameters that are ultimately provided to the incremental PID control model for calculating the control input.

[0093] In one possible implementation, the short-cycle thread obtains the current operating condition PID control parameter adjustment from S601 and the updated reference PID control parameters read from shared memory, and multiplies them term by term to obtain the complete PID control parameters for the current operating condition. These parameters, together with the updated protection potential reference value in shared memory, constitute the target control parameters. After combination, the thread stores the target control parameters in a global structure variable directly accessible by the incremental PID control model.

[0094] It should be noted that the direct combination method is adopted in the steady-state operation phase, which can avoid the additional processing delay introduced by interpolation calculation, and ensure that the control cycle of the system maintains the shortest path when the operating conditions are stable, thereby ensuring that the steady-state control accuracy is not affected by the smooth transition algorithm.

[0095] Based on the above steps, during steady-state operation without switching operating conditions, the target control parameters are generated by direct combination, avoiding unnecessary computational overhead and ensuring the real-time performance and steady-state accuracy of the control loop.

[0096] S604. When the cathodic protection operating conditions at the current sampling time are inconsistent with those at the previous sampling time, the PID control parameters before and after the switching are obtained based on the updated cathodic protection control reference parameters. The PID control parameters before and after the switching are interpolated according to the preset sliding time window to obtain the target control parameters.

[0097] The PID control parameters before the switch are the set of steady-state PID control parameters currently used by the short-cycle thread at the moment of the operating condition switch. These parameters can be obtained through direct combination of PID parameters or from the steady-state parameters after interpolation. The PID control parameters after the switch are the set of PID control parameters corresponding to the target operating condition, obtained by combining the adjustment amount of the current operating condition with the updated baseline PID parameters. The preset sliding time window refers to a transition mechanism that dynamically weights and mixes the two sets of PID parameters within a certain time interval after the operating condition switch occurs. Its purpose is to allow the control parameters to migrate from the old value to the new value gradually rather than abruptly.

[0098] In one possible implementation, when a switch in the current cathodic protection operating condition is detected, a sliding time window of a preset length is established. The PID control parameters corresponding to the start time of the window are used as the PID control parameters before the switch, and the PID control parameters corresponding to the current cathodic protection operating condition are used as the PID control parameters after the switch. A dynamic weighting factor is determined based on the ratio of the number of steps in the sliding time window at the current sampling time to the preset window length. The PID control parameters before and after the switch are weighted according to the dynamic weighting factor to obtain the target control parameter corresponding to the current sampling time. When the sliding time window ends, the PID control parameter after the switch is determined as the target control parameter.

[0099] Furthermore, the preset window length N can be calibrated based on the system sampling period and the response time constant of the IGBT device in the power execution unit, typically taking a value of 5 to 10 sampling periods. In this embodiment, N=5 is used as an example for illustration. Let the moment when the operating condition switch is detected be the start time of the window. During the window Dynamic weighting factor Calculate as follows: The weighting factor gradually increases from 0 at the start time to 1 at the end time, controlling the proportion of the PID parameters in the interpolation result after the switch. At any sampling time k within the window, the target PID parameter set... From the PID parameter set before switching and the PID parameter set after switching By weight Linear interpolation yields the result, i.e. This formula applies to each PID component in the parameter set ( , , Each is executed independently. When hour, , Once the sliding time window ends, the system exits the interpolation transition mode and enters steady-state operation, with subsequent cycles directly combining parameters.

[0100] It should be noted that the use of sliding time window interpolation instead of simple delay switching is to ensure the mathematical continuity of the control voltage increment, thereby protecting the power execution hardware and the underlying surface polarization film.

[0101] Based on the above steps, by establishing a preset sliding time window at the time of switching between operating conditions, the PID control parameters before and after the switching are gradually weighted and interpolated with dynamic weighting factors, so that the target control parameters gradually transition from the old value to the new value in a continuous and smooth manner within the transition range, ensuring the mathematical continuity of the control voltage increment, eliminating the electrical impact of parameter mutations on IGBT power devices and the surface polarization film of the foundation, and realizing the disturbance-free switching of protection current between multiple operating conditions.

[0102] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0103] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A method for controlling cathodic protection of offshore wind turbines based on dual time scales, characterized in that, The method includes: Acquire protection potential data, environmental monitoring data, and cathodic protection power supply operation data of offshore wind turbine foundations; wherein, the environmental monitoring data includes tide level data, seawater flow velocity data, and seawater temperature data, and the cathodic protection power supply operation data includes cathodic protection power supply output voltage and output current; Based on the protection potential data, tide level data and seawater flow velocity data, short-time scale operating condition identification is performed to determine the current cathodic protection operating condition. The equivalent polarization impedance of the wind turbine foundation is determined based on the seawater temperature data and the output voltage and current of the cathodic protection power supply, and the cathodic protection control reference parameters are updated according to the seawater temperature data and the equivalent polarization impedance. Based on the current cathodic protection operating conditions, the corresponding control parameters are invoked, and the target control parameters are generated by combining the updated cathodic protection control reference parameters. The cathodic protection control quantity is determined based on the protection potential data, target control parameters, and preset control algorithm, and the cathodic protection power supply output is adjusted according to the cathodic protection control quantity.

2. The method according to claim 1, characterized in that, The step of identifying the current cathodic protection operating condition based on the protection potential data, tide level data, and seawater flow velocity data on a short timescale includes: The tidal level variation rate is calculated based on tidal level data from multiple consecutive sampling times, and the tidal level variation rate and seawater flow velocity data are input into the working condition state machine. The operating condition state machine compares the seawater flow velocity data with a preset flow velocity threshold. When the seawater flow velocity data is greater than the preset flow velocity threshold, the current cathodic protection operating condition is determined to be a severe sea condition. When the seawater flow velocity data is not greater than the preset flow velocity threshold, the operating condition state machine determines the current cathodic protection operating condition as either a tidal steady-state condition or a tidal variation condition based on the tidal level variation rate and the preset hysteresis judgment rule.

3. The method according to claim 2, characterized in that, The operating condition state machine determines whether the current cathodic protection operating condition is a steady-state tidal condition or a fluctuating tidal condition based on the tidal level variation rate and a preset hysteresis judgment rule, including: Set a first rate of change threshold and a second rate of change threshold corresponding to the rate of change of tide level, wherein the first rate of change threshold is greater than the second rate of change threshold. When the current cathodic protection operating condition is a tidal steady-state condition, and the tidal level variation rate is greater than the first variation rate threshold, the current cathodic protection operating condition is determined to be a tidal variation condition. When the current cathodic protection operation condition is tidal fluctuation condition, and the tidal level fluctuation rate is less than the second fluctuation rate threshold, the current cathodic protection operation condition is determined to be tidal steady state condition. When the tidal level fluctuation rate is greater than or equal to the second fluctuation rate threshold and less than or equal to the first fluctuation rate threshold, the current cathodic protection operating condition remains unchanged.

4. The method according to claim 1, characterized in that, The process of determining the equivalent polarization impedance of the wind turbine foundation based on the seawater temperature data and the output voltage and current of the cathodic protection power supply, and updating the cathodic protection control reference parameters according to the seawater temperature data and the equivalent polarization impedance, includes: The seawater temperature data collected within a preset long-term evaluation period are statistically processed to obtain the average seawater temperature. The equivalent polarization impedance of the wind turbine foundation is determined based on the output voltage and output current of the cathodic protection power supply. The temperature drift coefficient is determined based on the average seawater temperature, and the impedance aging coefficient is determined based on the equivalent polarization impedance. The preset cathodic protection control reference parameters are corrected based on the temperature drift coefficient and impedance aging coefficient to obtain the updated cathodic protection control reference parameters.

5. The method according to claim 4, characterized in that, The step of determining the temperature drift coefficient based on the average seawater temperature and the impedance aging coefficient based on the equivalent polarization impedance includes: The average seawater temperature is compared with a preset standard ambient temperature to determine the temperature deviation. The temperature drift coefficient is calculated based on the temperature deviation and the preset temperature correction model. The equivalent polarization impedance is compared with the preset standard polarization impedance to determine the impedance deviation; The impedance aging coefficient is calculated based on the impedance deviation and the preset impedance correction model.

6. The method according to claim 4, characterized in that, The step of correcting the preset cathodic protection control reference parameters based on the temperature drift coefficient and impedance aging coefficient to obtain updated cathodic protection control reference parameters includes: Obtain preset cathodic protection control reference parameters under standard conditions. The cathodic protection control reference parameters include the protection potential reference value and the corresponding PID control parameters. The protection potential reference value is compensated based on the temperature drift coefficient to obtain an updated protection potential reference value; The PID control parameters are compensated based on the impedance aging coefficient to obtain updated PID control parameters; The updated protection potential reference value and the updated PID control parameters are used as the updated cathodic protection control reference parameters.

7. The method according to claim 1, characterized in that, The step of calling the corresponding control parameters according to the current cathodic protection operating condition and generating target control parameters in combination with the updated cathodic protection control reference parameters includes: Based on the current cathodic protection operating condition, the PID control parameters corresponding to the current cathodic protection operating condition are retrieved from the preset operating condition parameter library; Determine whether the cathodic protection operating conditions at the current sampling time are consistent with those at the previous sampling time; When the cathodic protection operating condition at the current sampling time is consistent with the cathodic protection operating condition at the previous sampling time, the called PID control parameters will be combined with the updated cathodic protection control reference parameters to generate the target control parameters. When the cathodic protection operating conditions at the current sampling time are inconsistent with those at the previous sampling time, the PID control parameters before and after the switch are obtained based on the updated cathodic protection control reference parameters. The target control parameters are then obtained by interpolation calculation of the PID control parameters before and after the switch according to a preset sliding time window.

8. The method according to claim 7, characterized in that, The step of interpolating the PID control parameters before and after the switch according to a preset sliding time window to obtain the target control parameters includes: When a switch in the current cathodic protection operating condition is detected, a sliding time window with a preset window length is established, and the PID control parameters corresponding to the start time of the window are used as the PID control parameters before the switch, and the PID control parameters corresponding to the current cathodic protection operating condition are used as the PID control parameters after the switch. The dynamic weighting factor is determined based on the ratio of the number of steps in the sliding time window at the current sampling time to the preset window length. The target control parameters corresponding to the current sampling time are obtained by weighting the PID control parameters before and after the switching according to the dynamic weighting factor. When the sliding time window ends, the switched PID control parameters are determined as the target control parameters.

9. The method according to claim 1, characterized in that, The step of determining the cathodic protection control quantity based on the protection potential data, target control parameters, and preset control algorithm includes: Calculate the potential deviation based on the protection potential data and the updated protection potential reference value; The potential deviation and the proportional, integral and derivative parameters in the target control parameters are input into the incremental PID control model to calculate the control voltage increment. The cathodic protection control quantity at the current moment is determined based on the control voltage increment at the current moment and the control voltage at the previous moment.

10. A cathodic protection control system for offshore wind turbines based on dual time scales, applied to the method described in any one of claims 1-9, characterized in that, The system includes: The environment and status perception module is used to acquire the protection potential data, environmental monitoring data, and cathodic protection power supply operation data of the offshore wind turbine foundation; wherein, the environmental monitoring data includes tide level data, seawater flow velocity data, and seawater temperature data, and the cathodic protection power supply operation data includes the output voltage and output current of the cathodic protection power supply. The dual-timescale main control unit, employing an embedded Linux system and configured with a multi-task concurrent processing mechanism, is used to identify short-timescale operating conditions based on the protection potential data, tide level data, and seawater flow velocity data, determining the current cathodic protection operating condition; determining the equivalent polarization impedance of the wind turbine foundation based on the seawater temperature data and the output voltage and current of the cathodic protection power supply, and updating the cathodic protection control reference parameters according to the seawater temperature data and equivalent polarization impedance; and calling the corresponding control parameters according to the current cathodic protection operating condition, and generating target control parameters by combining the updated cathodic protection control reference parameters. The power execution unit includes an IGBT full-bridge inverter circuit and a drive circuit, which is used to determine the cathodic protection control quantity according to the protection potential data, target control parameters and preset control algorithm, and adjust the cathodic protection power output according to the cathodic protection control quantity. The output terminal of the cathodic protection power supply is used to apply the adjusted DC protection current of the cathodic protection power supply to the auxiliary anode of the offshore wind turbine foundation to form a cathodic protection electric field in the seawater environment. The remote monitoring module communicates with the dual-timescale main control unit via industrial Ethernet or CAN bus, and is used to upload system operating status, environmental monitoring data, protection potential data and PID control parameters to the wind farm central control center.

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