A combined control system of wind power generation and high voltage direct current equipment

Abstract

This invention discloses a joint control system for wind power generation and high-voltage direct current (HVDC) equipment, comprising: a wind farm data acquisition unit for real-time acquisition of meteorological and operational parameters from the wind farm side, wherein the meteorological parameters include wind speed, wind direction, and air density, and the operational parameters include the active power output, rotor speed, and pitch angle of each wind turbine generator set; this invention relates to the field of wind power generation technology, and its beneficial effect is that by setting a central coordination controller and integrating an active power coordination control module, a DC voltage stabilization control module, and a dynamic energy buffer control module, it breaks down the traditional barriers between independent wind power generation control and HVDC control, achieving deep integration of the wind farm side and the HVDC transmission side at the information and decision-making levels, significantly improving the overall coordination and dynamic response speed of the system.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, and in particular to a combined control system for wind power generation and high-voltage direct current equipment. Background Technology

[0002] With the transformation of the global energy structure, renewable energy sources, represented by wind power, have been developed and utilized on a large scale. Large-scale offshore wind farms typically utilize high-voltage direct current (HVDC) transmission for grid connection to achieve long-distance, high-capacity power transmission. However, wind power generation exhibits significant intermittency, volatility, and uncertainty, creating an inherent contradiction between its output characteristics and the steady-state operation requirements of HVDC transmission systems. In traditional control architectures, the energy management system on the wind farm side and the control system on the HVDC transmission side operate independently. The former focuses solely on the active power tracking of the wind turbine generators, while the latter prioritizes DC voltage stability and the safe operation of the converter. The lack of effective information exchange and coordinated control mechanisms between the two leads to problems such as significant fluctuations in DC bus voltage, decreased wind energy utilization, converter overload, and even protective shutdowns under conditions of drastic wind speed changes and grid faults. Furthermore, existing joint control schemes often employ simple power limiting or lag control, making it difficult to achieve an optimal balance between dynamic response speed, system stability margin, and wind energy capture efficiency. Therefore, this paper addresses these issues through in-depth research. Summary of the Invention

[0003] The purpose of this invention is to solve the aforementioned problems by designing a joint control system for wind power generation and high-voltage direct current (HVDC) equipment. This addresses the challenges posed by the large-scale development and utilization of renewable energy sources, represented by wind power, in response to the global energy structure transformation. Large-scale offshore wind farms typically utilize HVDC transmission for grid connection, enabling long-distance, high-capacity power transmission. However, wind power generation exhibits significant intermittency, volatility, and uncertainty, creating an inherent contradiction between its output characteristics and the steady-state operation requirements of HVDC transmission systems. In traditional control architectures, the energy management system on the wind farm side and the control system on the HVDC transmission side operate independently. The former focuses solely on the active power tracking of the wind turbine generators, while the latter prioritizes DC voltage stability and the safe operation of the converter. The lack of effective information exchange and collaborative control mechanisms between the two leads to problems such as significant fluctuations in DC bus voltage, decreased wind energy utilization, converter overload, and even protective shutdowns under conditions of drastic wind speed changes and grid faults. In addition, existing joint control schemes mostly employ simple power limiting or lag control, which makes it difficult to achieve an optimal balance between dynamic response speed, system stability margin and wind energy capture efficiency.

[0004] The technical solution of the present invention to achieve the above objectives is: a joint control system for wind power generation and high-voltage direct current equipment, comprising: The wind farm data acquisition unit is used to collect meteorological and operational parameters from the wind farm side in real time. The meteorological parameters include wind speed, wind direction and air density, and the operational parameters include the active power output, rotor speed and pitch angle of each wind turbine generator set. The high-voltage direct current (HVDC) equipment data acquisition unit is used to acquire electrical parameters of the HVDC transmission equipment in real time. These electrical parameters include DC bus voltage, DC current, converter firing angle, converter transformer valve side voltage, and AC grid connection point voltage. The central coordination controller is communicatively connected to the wind farm data acquisition unit and the high-voltage DC equipment data acquisition unit, respectively. The central coordination controller integrates an active power coordination control module, a DC voltage stabilization control module and a dynamic energy buffer control module. The active power coordination control module receives the meteorological parameters and the operating parameters, establishes a wind power prediction model, and generates active power commands for the wind farm side based on the prediction results. The DC voltage stabilization control module receives the electrical parameters and generates converter control commands for the high-voltage DC equipment side based on the current DC bus voltage deviation and converter operating status. The dynamic energy buffer control module calculates the system's equivalent inertial time constant in real time, and when a system power imbalance is detected, it coordinates with the active power coordination control module and the DC voltage stabilization control module to dynamically adjust the kinetic energy release of the wind turbine and the power modulation of the converter.

[0005] Preferably, the active power coordination control module contains a multi-objective optimization function. This function aims to maximize wind energy capture efficiency, minimize mechanical fatigue load, and smooth grid-connected power fluctuations. It uses rotor speed constraints, pitch angle change rate constraints, and converter capacity constraints of the wind turbine generator set as constraints. The optimized active power setpoint of each wind turbine generator set is obtained by solving the multi-objective optimization function.

[0006] Preferably, the DC voltage stabilization control module adopts a voltage regulator based on model predictive control. The voltage regulator predicts the DC voltage trajectory in the future multiple control cycles based on the current measured value of DC bus voltage, measured value of DC current and phase angle of AC side voltage of converter, and optimizes the firing angle command and shutdown angle command of converter in a rolling manner with the goal of minimizing the weighted sum of voltage deviation and control cost.

[0007] Preferably, the dynamic energy buffer control module is internally configured with an energy buffer state evaluation model, which is based on the formula... Ebuf ( t )=1 / 2 Jeqωr 2( t )+1 / 2 CdcVdc 2(t ) Calculate the total buffer energy of the system, where Jeq The equivalent rotational inertia of the wind farm, ωr ( t () represents the equivalent rotor speed of the wind farm. Cdc This is the equivalent capacitance on the DC side. Vdc ( t ) represents the DC bus voltage; the dynamic energy buffer control module determines the degree of system power disturbance based on the rate of change of the total buffer energy of the system, and generates a corresponding additional power adjustment amount.

[0008] Preferably, when the dynamic energy buffer control module detects a system power imbalance, it determines the appropriate power level based on the formula Δ. Pref = Kp dt / dEbuf + Ki ∫ dEbuf / dt The additional power adjustment amount is calculated, where Kp is the proportional coefficient and KiKi is the integral coefficient, and the additional power adjustment amount is sent to the active power coordination control module and the DC voltage stabilization control module respectively, so as to realize the coordinated release or absorption of the rotor kinetic energy of the wind turbine and the DC capacitor energy storage.

[0009] Preferably, the central coordination controller further includes a fault ride-through mode switching module. The fault ride-through mode switching module monitors the AC grid connection point voltage and DC bus voltage in real time. When the voltage drop amplitude is detected to exceed a preset threshold, the system is switched from normal operation mode to low voltage fault ride-through mode. In low voltage fault ride-through mode, the active power coordination control module forcibly limits the output of the wind turbine generator set, and the DC voltage stabilization control module switches to a reactive power priority control strategy to provide reactive power support to the AC grid.

[0010] Preferably, in the low-voltage fault ride-through mode, the active power coordination control module, according to the formula... Pwref = Pwpre (1- α VacnomVacnom - Vac ) Calculate the forced limit value of active power, where Pwpre The active power before the fault. Vacnom The rated voltage of the AC grid connection point, Vac The voltage at the AC grid connection point is the real-time voltage, and α is the power reduction factor. The DC voltage stabilization control module is based on the formula Qref =min( Qmax ,β ( Vacnom - Vac )) Calculate the reactive power command, where Qmax β represents the maximum reactive power capacity of the converter, and β is the reactive power support coefficient.

[0011] Preferably, both the wind farm data acquisition unit and the high-voltage DC equipment data acquisition unit adopt a time synchronization mechanism based on the IEEE 1588 precise time protocol to ensure that the synchronization error of the acquired data is less than 1 microsecond; the central coordination controller executes a joint control algorithm based on the synchronized data, with a control cycle of 100 microseconds to 500 microseconds.

[0012] Preferably, the central coordination controller further includes a parameter adaptive correction module. The parameter adaptive correction module corrects the control parameters in the active power coordination control module, the DC voltage stabilization control module, and the dynamic energy buffer control module online according to the actual operating conditions of the wind farm and the aging degree of the high-voltage DC equipment. The correction is based on the criterion of minimizing the weighted sum of squares of the system dynamic response error and steady-state deviation.

[0013] Preferably, the joint control system further includes a monitoring and early warning platform connected to the central coordinating controller. The monitoring and early warning platform is used to visualize the real-time operating status, key control parameters and system stability margin of the wind farm and high-voltage DC equipment, and to issue a graded early warning signal when the system stability margin is detected to be lower than the preset safety boundary.

[0014] This invention discloses a joint control system for wind power generation and high-voltage direct current (HVDC) equipment. By setting up a central coordinating controller and integrating an active power coordination control module, a DC voltage stabilization control module, and a dynamic energy buffer control module, it breaks down the traditional barriers between independent wind power generation control and HVDC control. This achieves deep integration of the wind farm side and the HVDC transmission side at the information and decision-making levels, significantly improving the overall coordination and dynamic response speed of the system. Specifically, the dynamic energy buffer control module calculates the total buffer energy of the system in real time. This total buffer energy comprehensively represents the rotational kinetic energy of the wind turbine and the energy stored in the DC capacitor. Based on its rate of change, it generates an additional power adjustment amount. Therefore, when power disturbances occur, it can collaboratively utilize the rotor kinetic energy of the wind turbine and the energy stored in the DC capacitor to resist the disturbances, effectively increasing the system's inertial time constant and effectively suppressing fluctuations in the DC bus voltage. The active power coordination control module adopts a multi-objective optimization function, maximizing wind energy capture efficiency while considering mechanical fatigue load and grid-connected power smoothness, avoiding the mechanical fatigue load caused by pursuing maximum power in traditional control methods. The system addresses issues such as excessive fatigue or severe power fluctuations, extending equipment lifespan and improving power quality. The DC voltage stabilization control module employs a model predictive control strategy, enabling prediction and rolling optimization of voltage trajectories for multiple future cycles based on the system's dynamic model. Compared to traditional proportional-integral control, it exhibits better dynamic response characteristics and robustness, especially during transient processes such as grid faults, more accurately limiting voltage overshoot and oscillations. By setting a fault ride-through mode switching module and corresponding control strategies, the system automatically adjusts the control objectives of the wind turbine and converter when grid voltage drops, switching from power priority to reactive power support priority. This ensures the system meets the grid guidelines' requirements for fault ride-through capability, improving the reliability of wind power grid connection. Furthermore, the introduction of a parameter adaptive correction module optimizes control parameters online based on changes in operating conditions and equipment aging, maintaining optimal control performance throughout the system's lifespan. Simultaneously, a high-precision time synchronization acquisition mechanism and high-speed control cycle ensure the real-time performance and accuracy of joint control, providing a reliable guarantee for the safe and stable operation of large-scale wind power transmission systems via high-voltage DC. Detailed Implementation

[0015] The present invention will now be described in detail as a combined control system for wind power generation and high-voltage direct current equipment.

[0016] Example: A combined control system for wind power generation and high-voltage direct current equipment includes: The wind farm data acquisition unit is used to collect meteorological and operational parameters from the wind farm side in real time. The meteorological parameters include wind speed, wind direction and air density, and the operational parameters include the active power output, rotor speed and pitch angle of each wind turbine generator. The high-voltage direct current (HVDC) equipment data acquisition unit is used to collect electrical parameters on the HVDC transmission equipment side in real time. These electrical parameters include DC bus voltage, DC current, converter firing angle, converter transformer valve side voltage, and AC grid connection point voltage. The central coordination controller is connected to the wind farm data acquisition unit and the high-voltage DC equipment data acquisition unit. The central coordination controller integrates an active power coordination control module, a DC voltage stabilization control module and a dynamic energy buffer control module. The active power coordination control module receives meteorological and operational parameters, establishes a wind power prediction model, and generates active power commands for the wind farm side based on the prediction results. The DC voltage stabilization control module receives electrical parameters and generates converter control commands for the high-voltage DC equipment side based on the current DC bus voltage deviation and converter operating status. The dynamic energy buffer control module calculates the system's equivalent inertial time constant in real time, and when a system power imbalance is detected, it coordinates with the active power coordination control module and the DC voltage stabilization control module to dynamically adjust the kinetic energy release of the wind turbine and the power modulation of the converter.

[0017] Specifically, the active power coordination control module contains a multi-objective optimization function. This function aims to maximize wind energy capture efficiency, minimize mechanical fatigue load, and smooth grid-connected power fluctuations. It uses rotor speed constraints, pitch angle change rate constraints, and converter capacity constraints of the wind turbine generator set as constraints. The optimized active power setpoint of each wind turbine generator set is obtained by solving the multi-objective optimization function.

[0018] Specifically, the DC voltage stabilization control module adopts a voltage regulator based on model predictive control. The voltage regulator predicts the DC voltage trajectory in the future multiple control cycles based on the current measured DC bus voltage, measured DC current, and AC side voltage phase angle of the converter. It also optimizes the converter's firing angle command and shutdown angle command in a rolling manner with the goal of minimizing the weighted sum of voltage deviation and control cost.

[0019] Specifically, the dynamic energy buffer control module is equipped with an energy buffer state assessment model, which is based on the formula... Ebuf ( t )=1 / 2 Jeqωr 2( t )+1 / 2 CdcVdc 2( t ) Calculate the total buffer energy of the system, where Jeq The equivalent rotational inertia of the wind farm, ωr ( t () represents the equivalent rotor speed of the wind farm. Cdc This is the equivalent capacitance on the DC side. Vdc ( t) represents the DC bus voltage; the dynamic energy buffer control module determines the degree of power disturbance in the system based on the rate of change of the total buffer energy of the system, and generates the corresponding additional power adjustment.

[0020] Specifically, when the dynamic energy buffer control module detects a system power imbalance, it uses the formula Δ Pref = Kp dt / dEbuf + Ki ∫ dEbuf / dt Calculate the additional power regulation, K p This is the proportionality coefficient. Ki The integral coefficient is used, and this additional power adjustment is sent to the active power coordination control module and the DC voltage stability control module respectively, so as to realize the coordinated release or absorption of the rotor kinetic energy and DC capacitor energy storage of the wind turbine.

[0021] Specifically, the central coordination controller also includes a fault ride-through mode switching module. The fault ride-through mode switching module monitors the AC grid connection point voltage and DC bus voltage in real time. When the voltage drop amplitude is detected to exceed the preset threshold, the system is switched from normal operation mode to low voltage fault ride-through mode. In low voltage fault ride-through mode, the active power coordination control module forcibly limits the output of the wind turbine generator, and the DC voltage stabilization control module switches to a reactive power priority control strategy to provide reactive power support to the AC grid.

[0022] Specifically, in the low-voltage fault ride-through mode, the active power coordination control module, according to the formula... Pwref = Pwpre (1- α VacnomVacnom - Vac ) Calculate the forced limit value of active power, where Pwpre The active power before the fault. Vacnom The rated voltage of the AC grid connection point, Vac The voltage at the AC grid connection point is the real-time voltage, and α is the power reduction factor. The DC voltage stabilization control module uses the formula Qref =min( Qmax , β ( Vacnom - Vac )) Calculate the reactive power command, where Qmax β represents the maximum reactive power capacity of the converter, and β is the reactive power support coefficient.

[0023] Specifically, both the wind farm data acquisition unit and the high-voltage DC equipment data acquisition unit adopt a time synchronization mechanism based on the IEEE 1588 precise time protocol to ensure that the synchronization error of the acquired data is less than 1 microsecond; the central coordination controller executes a joint control algorithm based on the synchronized data, with a control cycle of 100 microseconds to 500 microseconds.

[0024] Specifically, the central coordination controller also includes a parameter adaptive correction module. Based on the actual operating conditions of the wind farm and the aging degree of the high-voltage DC equipment, the parameter adaptive correction module corrects the control parameters in the active power coordination control module, DC voltage stability control module and dynamic energy buffer control module online. The correction is based on the criterion of minimizing the weighted sum of squares of the system dynamic response error and steady-state deviation.

[0025] Specifically, the joint control system also includes a monitoring and early warning platform connected to the central coordinating controller. The monitoring and early warning platform is used to visualize the real-time operating status, key control parameters and system stability margin of the wind farm and high-voltage DC equipment, and to issue graded early warning signals when the system stability margin is detected to be lower than the preset safety boundary.

[0026] It should be noted that the joint control system for wind power generation and high-voltage direct current (HVDC) equipment mainly consists of three parts: a wind farm data acquisition unit, a HVDC equipment data acquisition unit, and a central coordination controller. The wind farm data acquisition unit is deployed within the wind farm's booster station and connects to the controllers of each wind turbine generator and sensors such as anemometers and wind vanes via a fieldbus. It acquires real-time data on wind speed, wind direction, air density, real-time active power of each turbine, rotor speed, and pitch angle at millisecond sampling periods. The HVDC equipment data acquisition unit is installed in the control and protection cabinet of the HVDC converter station. It acquires secondary side signals from the DC bus voltage transformer, DC current transformer, converter transformer valve-side voltage transformer, and AC grid connection point voltage transformer via hard-wiring, obtaining DC bus voltage, DC current, converter firing angle, converter transformer valve-side voltage, and AC grid connection point voltage. The central coordination controller uses a high-performance industrial control computer with an embedded real-time operating system and establishes communication links with the two acquisition units via fiber optic Ethernet. To ensure the effectiveness of joint control, both acquisition units are equipped with GPS timing modules and synchronize their clocks according to the IEEE 1588 precision time protocol, ensuring that the timestamp synchronization error of all acquired data is strictly controlled within 1 microsecond. Upon receiving the synchronization data, the central coordination controller operates its integrated active power coordination control module, DC voltage stabilization control module, and dynamic energy buffer control module with a fixed control cycle of 250 microseconds. The active power coordination control module is the core of this system for achieving optimized control on the wind farm side. This module first uses the received meteorological and operational parameters to establish a wind power prediction model based on a long short-term memory neural network. This model can predict the ultra-short-term wind power output for the next 5 to 30 seconds based on the wind speed, wind direction sequence, and turbine operating status of the past 15 minutes. Subsequently, the module's internal multi-objective optimization function is activated. This function maximizes wind energy capture efficiency, minimizes mechanical fatigue load, and smooths grid-connected power fluctuations as three parallel optimization objectives. Wind energy capture efficiency is characterized by the ratio of tip speed ratio to wind energy utilization coefficient; mechanical fatigue load is estimated by the weighted sum of pitch angle action frequency and rotor speed variation; and power fluctuation is measured by the absolute value of the difference in active power commands between adjacent control cycles. Constraints include that the rotor speed of the wind turbine generator must be between the minimum and maximum speeds, the pitch angle change rate must not exceed the set maximum value, and the converter capacity limit for each unit. This multi-objective optimization problem is solved using a non-dominated sorting genetic algorithm with an elitist strategy. The module generates the optimal active power setpoint for each wind turbine generator in the wind farm. This setpoint not only ensures rapid tracking of the maximum power point during wind speed fluctuations but also reduces fatigue damage to the pitch bearings by limiting drastic pitch angle movements and keeps power fluctuations injected into the high-voltage direct current system within acceptable limits.The DC voltage stabilization control module is responsible for maintaining voltage stability in the HVDC transmission system. This module incorporates a voltage regulator based on model predictive control (MMC). In each control cycle, the regulator acquires the measured DC bus voltage, measured DC current, and AC-side voltage phase angle of the converter at the current moment. Based on the discrete-time state-space model of the HVDC transmission system, it predicts the DC voltage trajectory over the next five control cycles. The objective function of MMC is designed as the sum of the squares of voltage deviations and the weighted sum of control costs, where the control costs include the squares of the changes in the firing angle command and the turn-off angle command. By solving a quadratic programming problem under constraints, the module continuously optimizes the firing angle and turn-off angle commands for the next moment. Compared to traditional proportional-integral-derivative (PID) control, this control strategy can predict and compensate for voltage change trends in advance, effectively suppressing DC voltage transient overshoot caused by sudden power changes in the wind farm or AC-side faults. This significantly improves the dynamic accuracy and stability of voltage control. The dynamic energy buffer control module is crucial for the coordinated operation of the wind farm and HVDC equipment in this system. The energy buffer state assessment model configured inside this module is based on the formula. Ebuf ( t )=1 / 2 Jeqωr 2( t )+1 / 2 CdcVdc 2( t The total buffer energy of the system is calculated in real time. Among them, Jeq... Jeq It is the equivalent moment of inertia of the wind farm, ωr(t), obtained by summing the moments of inertia of all operating wind turbine generators. ωr ( t The equivalent rotor speed of the wind farm, Cdc, is obtained by weighted averaging of the rotor speeds of each unit. Cdc Vdc(t) is the equivalent capacitance to ground of a DC transmission system. Vdc ( t ) represents the real-time DC bus voltage. This formula unifies the rotational kinetic energy of the wind turbine and the electrostatic energy of the DC capacitor into the total system buffer energy, establishing a quantitative bridge for energy interaction between the mechanical and electrical sides. The module continuously monitors the derivative of this total buffer energy with respect to time, i.e., dEbuf / dt. dEbuf / dt When dEbuf / dt dEbuf / dt When the absolute value of Δ exceeds the set threshold, it indicates a significant power imbalance in the system. At this point, the dynamic energy buffer control module adjusts its response according to the formula Δ. Pref = Kp dt / dEbuf + Ki ∫ dEbuf / dt An additional power regulation is calculated. This regulation is essentially a compensation power based on the system's total energy change rate and its accumulated error. Subsequently, this additional power regulation is simultaneously sent to the active power coordination control module and the DC voltage stabilization control module. The former adjusts the power commands of each wind turbine generator accordingly, releasing or absorbing kinetic energy by adjusting the rotor speed; the latter adjusts the power commands of the converter accordingly, releasing or absorbing stored capacitor energy by changing the DC voltage. This coordinated mechanism enables wind turbine generators to accelerate energy absorption and DC voltage to increase energy absorption when there is excess power; and wind turbine generators to decelerate and release kinetic energy and DC capacitors to discharge and replenish energy when there is a power deficit, thus achieving a joint inertial response to power disturbances. To cope with AC grid faults, the central coordination controller also integrates a fault ride-through mode switching module. This module monitors the AC grid connection point voltage and DC bus voltage in real time at a 1-millisecond cycle. When the AC grid connection point voltage drop exceeds a preset threshold, the module immediately switches the system from normal operation mode to low-voltage fault ride-through mode. After the switch, the active power coordination control module is forced to limit its output, no longer pursuing maximum wind energy capture, but instead based on the formula... Pwref = Pwpre (1- α VacnomVacnom - Vac The active power forced limit value is calculated. This formula ensures that the active power output of the wind farm decreases linearly with the increase of voltage drop depth, thereby freeing up capacity for reactive power output. Simultaneously, the DC voltage stabilization control module switches to a reactive power priority control strategy, and its reactive power command should be based on the formula... Qref =min( Qmax , β ( Vacnom - Vac The calculation shows that reactive power is output according to a law proportional to the voltage deviation until the maximum reactive power capacity of the converter is reached. This strategy ensures that during grid faults, the HVDC converter station can provide voltage support to the grid like a traditional synchronous generator, significantly improving the fault ride-through capability of wind farm grid connection and preventing cascading grid disconnection accidents caused by voltage drops. Considering the time-varying nature of wind farm operating conditions and the parameter drift of HVDC equipment after long-term operation, the central coordination controller has specially designed a parameter adaptive correction module. This module continuously optimizes online with the error between the actual dynamic response and the expected response of the system as the objective. Specifically, the module collects the system's response data after being subjected to small power disturbances in real time, calculates the dynamic response error and steady-state deviation, and constructs a weighted sum of squares cost function based on this error data. With the objective of minimizing this cost function, the gradient descent method is used to correct the weight coefficients of the multi-objective optimization function in the active power coordination control module, the weight matrix of the model predictive control in the DC voltage stability control module, and the proportional coefficient in the dynamic energy buffer control module online. Kp and integral coefficient KiThrough this adaptive mechanism, the joint control system can maintain optimal control performance throughout the entire lifecycle of the equipment, overcoming the poor adaptability of traditional fixed-parameter controllers. To achieve precise coordination between the wind farm and the HVDC equipment, this system places extremely high demands on the synchronization of data acquisition and the real-time performance of control. Both the wind farm data acquisition unit and the HVDC equipment data acquisition unit have built-in high-precision crystal oscillators and utilize the GPS second pulse signal for clock discipline, ensuring that the local clock of each acquisition unit remains highly consistent with GPS time. Simultaneously, the two acquisition units exchange synchronization messages conforming to the IEEE 1588 precise time protocol, strictly limiting the synchronization error of the acquired data to within 1 microsecond. The central coordination controller performs calculations based on the synchronized data with a unified timestamp, and its control cycle is set to 250 microseconds. This cycle is much smaller than the characteristic time constant of wind power fluctuations and the electromagnetic transient time constant of the HVDC system, enabling the controller to perceive system state changes "in real time" and intervene quickly, ensuring that the joint control algorithm can effectively cope with rapid transient processes. This joint control system is also equipped with a monitoring and early warning platform. The platform connects to the central coordinating controller via industrial Ethernet and uses a human-machine interface to display key operating parameters of the wind farm and HVDC equipment in real time, including but not limited to wind speed distribution maps, active power of each unit, DC bus voltage waveform, and converter firing angle variation trends. More importantly, the platform performs safety assessments based on system stability margin indicators (such as DC voltage stability margin and power angle stability margin) calculated by the central coordinating controller. When the stability margin indicator falls below the preset safety boundary, the platform issues warning signals according to the severity level: Level 1 warning (attention) prompts operators to pay attention to trend changes through a yellow warning box; Level 2 warning (alarm) prompts operators to intervene in a timely manner through red flashing and sound alerts; Level 3 warning (emergency) automatically triggers the central coordinating controller to initiate emergency power reduction or generator tripping preparation procedures. This platform provides operators with an intuitive and efficient tool for system status monitoring and risk assessment, improving the system's operation and maintenance management level. In actual operation, the joint control system of this invention exhibits excellent dynamic response characteristics. Taking a sudden increase in wind speed as an example, when a wind farm encounters a gust of wind, the wind farm data acquisition unit quickly captures the wind speed change. The active power coordination control module, based on ultra-short-term forecasts, anticipates a power surplus and adjusts the pitch angle of each turbine to limit the rapid increase in active power. Simultaneously, the dynamic energy buffer control module detects an increase in the system's total buffer energy, calculates the additional power adjustment based on its rate of change, and sends it to the DC voltage stabilization control module. Upon receiving the signal, the DC voltage stabilization control module appropriately increases the DC voltage setpoint, absorbing some of the instantaneous power by increasing DC capacitor energy storage, rather than relying entirely on the mechanical braking of the wind turbines, thus avoiding mechanical shock caused by excessively rapid pitch angle movements.If extremely drastic wind speed changes cause the system's total energy change rate to exceed a threshold, the central coordinating controller will coordinate all modules to jointly execute energy buffering and power stabilization strategies, ensuring that the DC bus voltage remains within the allowable range and achieving stable control of the entire system chain from the mechanical to the electrical side. In summary, the joint control system for wind power generation and high-voltage direct current (HVDC) equipment described in this embodiment, through deep integration of wind farm-side control and HVDC transmission-side control, and the introduction of a dynamic coordination mechanism based on total buffer energy, a voltage control strategy based on model prediction, and a power allocation method based on multi-objective optimization, effectively solves the technical challenges of poor coordination, insufficient dynamic response, and low stability margin in large-scale wind power transmission systems via HVDC. The system has achieved significant results in improving wind energy utilization, extending equipment lifespan, enhancing fault ride-through capability, and improving power quality, providing reliable technical support for high-proportion renewable energy grid integration.

[0027] The above technical solutions only embody the preferred technical solutions of the present invention. Any modifications that may be made by those skilled in the art to certain parts thereof embody the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A combined control system for wind power generation and high-voltage direct current equipment, characterized in that, include: The wind farm data acquisition unit is used to collect meteorological and operational parameters from the wind farm side in real time. The meteorological parameters include wind speed, wind direction and air density, and the operational parameters include the active power output, rotor speed and pitch angle of each wind turbine generator set. The high-voltage direct current (HVDC) equipment data acquisition unit is used to acquire electrical parameters of the HVDC transmission equipment in real time. These electrical parameters include DC bus voltage, DC current, converter firing angle, converter transformer valve side voltage, and AC grid connection point voltage. The central coordination controller is communicatively connected to the wind farm data acquisition unit and the high-voltage DC equipment data acquisition unit, respectively. The central coordination controller integrates an active power coordination control module, a DC voltage stabilization control module and a dynamic energy buffer control module. The active power coordination control module receives the meteorological parameters and the operating parameters, establishes a wind power prediction model, and generates active power commands for the wind farm side based on the prediction results. The DC voltage stabilization control module receives the electrical parameters and generates converter control commands for the high-voltage DC equipment side based on the current DC bus voltage deviation and converter operating status. The dynamic energy buffer control module calculates the system's equivalent inertial time constant in real time, and when a system power imbalance is detected, it coordinates with the active power coordination control module and the DC voltage stabilization control module to dynamically adjust the kinetic energy release of the wind turbine and the power modulation of the converter.

2. The joint control system for wind power generation and high-voltage direct current equipment according to claim 1, characterized in that, The active power coordination control module contains a multi-objective optimization function. This function aims to maximize wind energy capture efficiency, minimize mechanical fatigue load, and smooth grid-connected power fluctuations. It uses rotor speed constraints, pitch angle change rate constraints, and converter capacity constraints of the wind turbine generator set as constraints. The optimized active power setpoint for each wind turbine generator set is obtained by solving the multi-objective optimization function.

3. The combined control system for wind power generation and high-voltage direct current equipment according to claim 1, characterized in that, The DC voltage stabilization control module adopts a voltage regulator based on model predictive control. The voltage regulator predicts the DC voltage trajectory in the future multiple control cycles based on the current measured DC bus voltage, measured DC current, and AC side voltage phase angle of the converter. It also optimizes the converter's firing angle command and shutdown angle command in a rolling manner with the goal of minimizing the weighted sum of voltage deviation and control cost.

4. The combined control system for wind power generation and high-voltage direct current equipment according to claim 1, characterized in that, The dynamic energy buffer control module is internally configured with an energy buffer state assessment model, which is based on the formula... Ebuf ( t )=1 / 2 Jeqωr 2( t )+1 / 2 CdcVdc 2( t ) Calculate the total buffer energy of the system, where Jeq The equivalent rotational inertia of the wind farm, ωr ( t () represents the equivalent rotor speed of the wind farm. Cdc This is the equivalent capacitance on the DC side. Vdc ( t The DC bus voltage is denoted as ; the dynamic energy buffer control module determines the degree of system power disturbance based on the rate of change of the total buffer energy of the system, and generates a corresponding additional power adjustment amount.

5. The joint control system for wind power generation and high-voltage direct current equipment according to claim 1, characterized in that, When the dynamic energy buffer control module detects a system power imbalance, it uses the formula Δ Pref = Kp dt / dEbuf + Ki ∫ dEbuf / dt Calculate the additional power adjustment, where Kp This is the proportionality coefficient. Ki The integral coefficient is used, and the additional power adjustment amount is sent to the active power coordination control module and the DC voltage stabilization control module respectively, so as to realize the coordinated release or absorption of the rotor kinetic energy of the wind turbine and the DC capacitor energy storage.

6. The combined control system for wind power generation and high-voltage direct current equipment according to claim 1, characterized in that, The central coordination controller also includes a fault ride-through mode switching module. The fault ride-through mode switching module monitors the AC grid connection point voltage and DC bus voltage in real time. When the voltage drop amplitude is detected to exceed a preset threshold, the system is switched from normal operation mode to low voltage fault ride-through mode. In low voltage fault ride-through mode, the active power coordination control module forcibly limits the output of the wind turbine generator set, and the DC voltage stabilization control module switches to a reactive power priority control strategy to provide reactive power support to the AC grid.

7. The combined control system for wind power generation and high-voltage direct current equipment according to claim 1, characterized in that, The active power coordination control module, in low-voltage fault ride-through mode, according to the formula... Pwref = Pwpre (1- α VacnomVacnom - Vac ) Calculate the forced limit value of active power, where Pwpre The active power before the fault. Vacnom The rated voltage of the AC grid connection point, Vac The voltage at the AC grid connection point is the real-time voltage, and α is the power reduction factor. The DC voltage stabilization control module is based on the formula Qref =min( Qmax , β ( Vacnom - Vac )) Calculate the reactive power command, where Qmax β represents the maximum reactive power capacity of the converter, and β is the reactive power support coefficient.

8. The joint control system for wind power generation and high-voltage direct current equipment according to claim 1, characterized in that, Both the wind farm data acquisition unit and the high-voltage DC equipment data acquisition unit adopt a time synchronization mechanism based on the IEEE 1588 precise time protocol to ensure that the synchronization error of the acquired data is less than 1 microsecond; the central coordination controller executes a joint control algorithm based on the synchronized data, with a control cycle of 100 microseconds to 500 microseconds.

9. The combined control system for wind power generation and high-voltage direct current equipment according to claim 1, characterized in that, The central coordination controller also includes a parameter adaptive correction module. The parameter adaptive correction module corrects the control parameters in the active power coordination control module, the DC voltage stability control module and the dynamic energy buffer control module online according to the actual operating conditions of the wind farm and the aging degree of the high voltage DC equipment. The correction is based on the criterion of minimizing the weighted sum of squares of the system dynamic response error and steady-state deviation.

10. The joint control system for wind power generation and high-voltage direct current equipment according to claim 1, characterized in that, The joint control system also includes a monitoring and early warning platform connected to the central coordinating controller. The monitoring and early warning platform is used to visualize the real-time operating status, key control parameters and system stability margin of the wind farm and high-voltage DC equipment, and to issue graded early warning signals when the system stability margin is detected to be lower than the preset safety boundary.