Method, system and equipment for adaptively improving inertial response effect and frequency damping based on phase locking error and medium

Abstract

The invention discloses a method, a system, equipment and a medium for adaptively improving an inertial response effect and frequency damping based on a phase-locked error, and relates to the technical field of power grid inertial response, and the method comprises the following steps: representing the phase-locked error through a q-axis voltage component obtained through coordinate transformation of a grid-connected point three-phase voltage signal; inputting the q-axis voltage component into an inertia control link to obtain an additional torque or active power instruction value; adaptively adjusting the damping coefficient T based on the absolute value of the q-axis voltage component; superposing the additional torque or active power instruction value with active power or torque instruction values generated in other links to obtain a target instruction value at the next moment; and d-axis and q-axis components of the excitation voltage are calculated through a proportional-integral controller, and a control signal of the rotor-side converter is generated through inverse coordinate transformation. A q-axis component in three-phase voltage of a grid-connected point is extracted to accurately represent a phase locking error, and in combination with adaptive damping adjustment, rapid identification and active response to power grid frequency disturbance are realized.

Description

Technical Field

[0001] This invention relates to the field of power grid inertial response technology, and in particular to a method, system, device and medium for adaptively improving inertial response and frequency damping based on phase-locked loop error. Background Technology

[0002] With the energy crisis and environmental pollution becoming increasingly severe, vigorously developing renewable energy sources such as wind power has gradually become a consensus. The high proportion of renewable energy integration leads to a prominent low inertia characteristic in new power systems, posing new challenges to the safe and stable operation of these systems.

[0003] Against this backdrop, with the increasing penetration rate of wind power, the randomness of wind power and the dynamic characteristics of doubly-fed induction generators (DFIGs) may have a significant impact on the small-disturbance stability of power systems, attracting increasing attention from scholars. The dynamic changes in the phase-locked loop (PLL) alter the dynamic characteristics of the DFIG, thus affecting the small-disturbance stability level of the system. Existing research on the impact on the small-disturbance stability of power systems mainly focuses on establishing a small-disturbance model for grid-connected interconnected systems considering both PLL and virtual inertia control for DFIG wind turbines with virtual inertia control. Based on this, analytical methods are used to reveal the mechanism of the small-disturbance stability of the system under the combined action of PLL and virtual inertia control. Specifically, for DFIG wind turbines with virtual inertia control, the PLL mainly affects the system damping by influencing the degree of virtual inertia's participation in the system: the smaller the PLL PI (proportional-integral) parameter, the smaller the participation factor of the virtual inertia control state variable in the interval oscillation mode, and the larger the damping ratio of the electromechanical oscillation mode. To address the challenge of analyzing doubly-fed inertial (DFIG) wind turbines with virtual inertia control due to their excessively high-order detailed models, this paper first analyzes the time constant of the DFIG, then studies the time-scale characteristics of its structural modules, and proposes a simplified model that retains virtual inertia control and phase-locked loop (PLL) dynamics based on the electromechanical coupling characteristics and decay rate differences of various state variables. However, this method of feeding the PLL error into the PI loop for inertia control has drawbacks, namely, a slow system inertia response speed, which does not meet the requirement for rapid inertia response. Therefore, it is urgent to optimize the inertia control loop to improve the system's inertia response speed. Summary of the Invention

[0004] In view of the above-mentioned problems, the present invention provides a method, system, device and medium for adaptively improving inertial response and frequency damping based on phase-locked loop error.

[0005] Therefore, the problem to be solved by the present invention is that the existing method of sending the phase-locked error into the PI circuit and then participating in the inertia control has defects, namely, the system inertia response speed is slow and does not meet the requirement of fast inertia response.

[0006] To address the aforementioned technical problems, this invention provides the following technical solution: a method for adaptively improving inertial response and frequency damping based on phase-locked error, comprising: acquiring the phase-locked error of the wind turbine at the current moment, wherein the phase-locked error is characterized by the q-axis voltage component obtained by coordinate transformation of the three-phase voltage signal at the grid connection point; inputting the q-axis voltage component into the inertial control loop to obtain an additional torque or active power command value; adaptively adjusting the damping coefficient T based on the absolute value of the q-axis voltage component; superimposing the additional torque or active power command value with active power or torque command values ​​generated by other loops to obtain a target command value for the next moment; calculating the d-axis and q-axis reference components of the excitation voltage through a proportional-integral controller according to the target command value, and generating a control signal for the rotor-side converter through inverse coordinate transformation to control the output of the doubly-fed wind turbine.

[0007] As a preferred embodiment of the method for adaptively improving inertial response and frequency damping based on phase-locked loop error described in this invention, the phase-locked loop error is characterized by the q-axis voltage component obtained by coordinate transformation of the three-phase voltage signal at the grid connection point, including: acquiring the three-phase voltage signal at the grid connection point and representing it using three-phase stationary coordinates; constructing a mapping relationship between the three-phase stationary coordinates and two-dimensional stationary coordinates based on the grid connection point voltage signal and the instantaneous reference phase angle obtained by the phase-locked loop; using the two-dimensional stationary coordinates and the instantaneous reference phase angle as inputs, and using Parker transformation to convert the quantities in the stationary coordinate system into d-axis and q-axis components in the synchronous rotating coordinate system; performing bandpass filtering on the obtained q-axis components to remove residual high-frequency components, and using the filtered q-axis components as the q-axis voltage component representation; the d-axis is the direct axis in a doubly-fed induction generator (DFIG) for wind power, used to represent the excitation component; the q-axis is the quadrature axis in a DFIG for wind power, representing the dynamic part of the output torque or current.

[0008] As a preferred embodiment of the method for adaptively improving inertial response and frequency damping based on phase-locked loop error described in this invention, the method for obtaining the additional torque or active power command value includes: inputting the q-axis component to the inertia control channel as a characterizing quantity of the system frequency change rate, reflecting the current grid disturbance level; constructing an inertia response adjustment channel based on the q-axis voltage component, extracting the active power or torque reference for inertia compensation, and calculating the additional torque or active power command value.

[0009] The advantages of this preferred technical solution are: dynamic adjustment of the additional torque helps to inject or absorb active power in a timely manner when the system frequency fluctuates, suppress frequency deviation, and improve grid stability. The additional torque control path constructed in this way is simple and efficient.

[0010] As a preferred embodiment of the method for adaptively improving inertial response and frequency damping based on phase-locked loop error described in this invention, the adaptive adjustment of the damping coefficient T based on the absolute value of the q-axis voltage component includes: processing the real-time value of the q-axis voltage component into its absolute value and dynamically calculating its amplitude, then performing a power calculation in conjunction with a set exponent n, and combining it with a scaling factor. The damping coefficient at the current moment is obtained by division; the dynamically calculated damping coefficient is used as the time constant parameter in the inertia control filter to update the calculation logic of the inertia control channel in real time.

[0011] As a preferred embodiment of the method for adaptively improving inertial response and frequency damping based on phase-locked loop error described in this invention, the relationship between the absolute value of the q-axis voltage component and the damping coefficient is expressed by the formula: in, Expressed as the damping coefficient, Represented as a scaling factor, It is represented as the q-axis voltage component.

[0012] As a preferred embodiment of the method for adaptively improving inertial response and frequency damping based on phase-locked loop error as described in this invention, the step of obtaining the target command value at the next moment includes obtaining two types of command values: the first type of command value is the additional torque or active power command output by the inertial response channel; the second type of command value is the basic power or torque reference value generated by the main control link of the wind turbine; the first type of command value and the second type of command value are fused to construct a unified target command value for the current control cycle; the unified target command value is used as the target power or torque reference signal for the current control cycle and input into the PI controller to drive the rotor excitation voltage output.

[0013] The beneficial effects of this preferred technical solution are as follows: Based on the dq axis current control structure, the active and reactive power channels are effectively decoupled, and the three-phase signal generated by the inverse transformation can accurately drive the rotor converter, avoiding the influence of coupling error.

[0014] As a preferred embodiment of the method for adaptively improving inertial response and frequency damping based on phase-locked loop error as described in this invention, the control of the doubly-fed induction generator output includes: constructing control paths in the d-axis and q-axis directions according to the target power or torque command value, and calculating the d-axis excitation voltage reference value and the q-axis excitation voltage reference value using a proportional-integral controller; inputting the obtained d-axis and q-axis excitation voltage reference values ​​to the inverse transformation module in the synchronous rotating coordinate system, and combining the instantaneous grid phase angle output by the phase-locked loop (PLL), performing the inverse transformation from the rotating coordinate system to the three-phase stationary coordinate system to obtain the three-phase excitation voltage command value; and inputting the three-phase excitation voltage reference value obtained by the coordinate inverse transformation to the converter, converting it into a control signal for driving the power switching devices of the rotor-side converter.

[0015] To address the aforementioned technical problems, this invention provides the following technical solution: a system for adaptively improving inertial response and frequency damping based on phase-locked loop error, comprising: an error acquisition module, a command value output module, an adjustment module, a command value superposition module, and a control module; the error acquisition module acquires the phase-locked loop error of the wind turbine at the current moment, the phase-locked loop error being characterized by the q-axis voltage component obtained by coordinate transformation of the three-phase voltage signal at the grid connection point; the command value output module inputs the q-axis voltage component into the inertial control loop to obtain an additional torque or active power command value; the adjustment module adaptively adjusts the damping coefficient T based on the absolute value of the q-axis voltage component; The command value superposition module superimposes the additional torque or active power command value with the active power or torque command values ​​generated by other links to obtain the target command value at the next moment. The control module calculates the d-axis and q-axis reference components of the excitation voltage through a proportional-integral controller based on the target command value, and generates the control signal of the rotor-side converter through coordinate inverse transformation to control the output of the doubly-fed wind turbine.

[0016] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of a method for adaptively improving inertial response and frequency damping based on phase-locked error as described above.

[0017] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for adaptively improving inertial response and frequency damping based on phase-locked error as described above.

[0018] The beneficial effects of this invention are as follows: By accurately characterizing the phase-locked loop error by extracting the q-axis component of the three-phase voltage at the grid connection point, the inertia control loop is guided to generate additional torque commands. Combined with adaptive damping regulation and multi-source power command fusion, the wind turbine unit achieves rapid identification and proactive response to grid frequency disturbances. Furthermore, by accurately generating converter control signals through PI control and inverse coordinate transformation, the excitation regulation has higher real-time performance and stability, improving the stability and friendliness of the wind turbine unit's grid-connected operation. This contributes to the construction of intelligent wind power support units with adjustable inertia, significantly improving the system's frequency safety margin. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of a method for adaptively improving inertial response and frequency damping based on phase-locked loop error in Example 1. Figure 2 This is a graph showing the active power curve of a doubly fed wind turbine in Example 3, which is based on phase-locked loop error adaptive improvement of inertial response and frequency damping. Figure 3 This is a dynamic curve of the system frequency of a system based on phase-locked error adaptive improvement of inertial response and frequency damping in Example 3. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a method for adaptively improving inertial response and frequency damping based on phase-locked loop error, comprising: S1: Obtain the phase-locked error of the wind turbine at the current moment. The phase-locked error is represented by the q-axis voltage component obtained by coordinate transformation of the three-phase voltage signal at the grid connection point.

[0024] S2: Input the q-axis voltage component into the inertia control loop to obtain the additional torque or active power command value.

[0025] S3: Adaptively adjust the damping coefficient T based on the absolute value of the q-axis voltage component.

[0026] S4: The additional torque or active power command value is superimposed on the active power or torque command values ​​generated by other links to obtain the target command value at the next moment.

[0027] S5: Based on the target command value, the d-axis and q-axis reference components of the excitation voltage are calculated by the proportional-integral controller, and the control signal of the rotor-side converter is generated by the inverse coordinate transformation to control the output of the doubly-fed wind turbine.

[0028] It should be noted that in traditional doubly-fed induction generator (DFIG) wind turbine control strategies, inertial response largely relies on wind speed fluctuations and passive power changes, lacking an active response mechanism based on system frequency disturbances. With high-penetration wind power integration, when system frequency fluctuations occur, the wind turbine cannot provide timely and effective inertial support, leading to excessive system frequency deviations and even triggering protection actions, seriously threatening grid stability. In existing technologies, phase-locked loops (PLLs) are commonly used to extract grid synchronization signals, but their performance significantly degrades under grid disturbances (such as voltage dips and harmonic interference), especially the q-axis component, which struggles to accurately reflect synchronization errors. This results in inaccurate extraction of inertia and frequency control signals, affecting the effectiveness of the entire control chain.

[0029] Therefore, regarding the above-mentioned issues, such as... Figure 1 As shown, through steps S1-S5, three-phase voltage signals are first collected from the wind turbine grid connection point. The q-axis component is extracted through coordinate transformation to characterize the phase-locked loop error and reflect the grid frequency change characteristics in real time. Then, the q-axis voltage component is input into the inertia response control loop, and an additional torque or active power command is generated based on its dynamic amplitude. The coordination of inertia support and frequency damping is achieved through adaptive adjustment of the damping coefficient. After that, the output of the inertia channel is fused with the main power control command to form the target torque or power command for the next moment. Finally, the target command is converted into an excitation voltage reference value through PI control and inverse coordinate transformation to generate a control signal to drive the converter. This enables the wind turbine to achieve fast and stable inertia response and dynamic voltage support during frequency disturbances, thereby improving the overall stability and inertia support capability of the grid.

[0030] Example 2, the second embodiment of the present invention, differs from the first embodiment in that: a method for adaptively improving inertial response and frequency damping based on phase-locked error further includes, in step S1, the q-axis voltage component characterization of the phase-locked error obtained by coordinate transformation of the three-phase voltage signal at the grid connection point includes the following steps A1-A4: A1: Collect the three-phase voltage signal at the grid connection point and represent it using three-phase stationary coordinates.

[0031] A2: Based on the grid connection point voltage signal and the instantaneous reference phase angle obtained by the phase-locked loop, a mapping relationship between the three-phase stationary coordinates and the two-dimensional stationary coordinates is constructed.

[0032] A3: Using two-dimensional stationary coordinates and instantaneous reference phase angle as inputs, the Parker transformation is used to convert the quantities in the stationary coordinate system into d-axis and q-axis components in the synchronous rotating coordinate system.

[0033] A4: Bandpass filtering is performed on the obtained q-axis component to remove residual high-frequency components, and the filtered q-axis component is used as the q-axis voltage component. In this context, the d-axis is the direct axis of the doubly-fed induction motor, used to represent the excitation component; the q-axis is the quadrature axis of the doubly-fed induction motor, representing the dynamic part of the output torque or current.

[0034] In this embodiment of the application, step A2, which constructs the mapping relationship between the three-phase stationary coordinates and the two-dimensional stationary coordinates, adopts a phase acquisition method based on Clarke transform and PI structure PLL, including the following steps A211-A213: A211: Perform Clarke transform on the acquired three-phase voltage signal at the grid connection point to obtain... shaft and Voltage components of the axis and .

[0035] A212: Will , The input is fed into a PI-structured phase-locked loop, where phase-locking operations are performed under a synchronous rotating coordinate reference frame, and the phase angle is output. .

[0036] A213: Use this phase angle as the rotation angle input for the subsequent Park transformation to achieve the mapping from the stationary coordinate system to the synchronously rotating coordinate system.

[0037] In an optional implementation, the mapping relationship between the three-phase stationary coordinates and the two-dimensional stationary coordinates can also be constructed using a phase acquisition method based on DSOGI (Dual Second-Order Generalized Integrator), including the following steps A221-A223: A221: Input the three-phase voltage signals into the dual second-order generalized integrator module respectively to obtain orthogonal... Quantity.

[0038] A222: The quadrature component is input into the DSOGI-PLL for phase-locked tracking, and a highly robust grid phase angle is output in real time. .

[0039] A223: Use this phase angle for Park transformation to generate dq-axis voltage / current components in a synchronous rotating coordinate system.

[0040] In another alternative implementation, the mapping relationship between the three-phase stationary coordinates and the two-dimensional stationary coordinates can also be constructed using a phase acquisition method based on Hilbert transform and instantaneous phase detection, including the following steps A231-A233: A233: Construct a complex signal from the three-phase voltage signal at the grid connection point, apply a Hilbert transform to it, and extract the imaginary part to construct an analytic signal.

[0041] A233: Based on the relative changes between the real and imaginary parts, the instantaneous phase of the voltage is calculated, thus obtaining... The amount of substitution.

[0042] A233: Use the instantaneous phase angle as the input for the Parker transformation to complete the coordinate transformation.

[0043] It should be noted that this step, by introducing coordinate transformation methods such as Clarke transform and Park transform, as well as a phase compensation mechanism, ensures that the q-axis component extracted from the three-phase voltage accurately reflects the deviation from the grid synchronization angle, thereby improving phase-locked loop (PLL) accuracy and response sensitivity. Introducing an anti-disturbance filtering module during PLL effectively suppresses the impact of grid disturbances (such as voltage dips, harmonics, and frequency fluctuations) on PLL performance, ensuring stable execution of the control logic. The q-axis voltage component sensitively reflects frequency disturbance information, providing a more sensitive and stable input signal for subsequent additional torque calculations.

[0044] Furthermore, in step S2, obtaining the additional torque or active power command value includes the following steps B1-B2: B1: Input the q-axis component into the inertia control channel as a characterization of the system frequency change rate, reflecting the current degree of power grid disturbance.

[0045] B2: Construct an inertia response adjustment channel based on the q-axis voltage component, extract the active power or torque reference for inertia compensation, and calculate the additional torque or active power command value.

[0046] In this embodiment of the application, step B2, which constructs the inertial response adjustment channel, adopts an inertial response channel based on a first-order inertial low-pass filter, including the following steps B211-B213: B211: The q-axis voltage component is introduced as an input signal into a first-order inertial filter, which is used to smooth short-term fluctuations in the input signal and extract the main trend component.

[0047] B212: The filter settings have two control parameters. The "proportional gain" is used to adjust the intensity of the inertial response, and the "time constant" is used to adjust the degree of response delay. The smaller the time constant, the faster the response.

[0048] B213: The output of the filter is the inertia response result, which is represented as an additional torque command value or active power reference value, and is used to superimpose it with the main control target.

[0049] In an optional implementation, the inertial response adjustment channel can also be constructed using an inertial response channel based on a differential structure, including the following steps B221-B223: B221: The q-axis voltage component is used as the input signal and a differential calculation structure is introduced to extract its trend over time, which is used to characterize the speed of power grid frequency disturbance.

[0050] B222: By setting a proportional coefficient, the rate of change is converted into an inertial response intensity, and a power or torque command value that is dynamically adjusted according to the rate of voltage change is output.

[0051] B223: To avoid high-frequency noise interference, the output value should be set with upper and lower thresholds, and a signal smoothing circuit can be added.

[0052] In another alternative implementation, the inertia response adjustment channel can also be constructed using an inertia response channel based on a virtual inertia controller, including the following steps B231-B233: B233: Input the q-axis voltage component into a two-parameter control structure that simulates the inertia and damping response mechanism of a traditional synchronous generator.

[0053] B233: By setting two parameters, the "virtual inertia coefficient" is used to control the degree of response to voltage change acceleration, and the "virtual damping coefficient" is used to adjust the degree of response to voltage change rate. Together, they determine the strength of the output signal and the shape of the response curve.

[0054] B233: This controller outputs a dynamically adjustable additional active power or torque command value and can adjust the control parameters in real time according to the system operating status to adapt to different power grid disturbance conditions.

[0055] It should be noted that this step reflects the frequency change trend through the dynamic amplitude of the q-axis voltage, enabling rapid and sensitive torque regulation, thereby enhancing the equivalent inertia response capability of the doubly-fed induction generator (DFIG) wind turbine. Dynamic adjustment of the additional torque helps to inject or absorb active power in a timely manner when the system frequency fluctuates, suppressing frequency drift and improving grid stability. The additional torque control path constructed in this way is simple and efficient, providing a foundation for building adjustable virtual inertia in wind farms.

[0056] Furthermore, in step S3, the adaptive adjustment of the damping coefficient T based on the absolute value of the q-axis voltage component includes the following steps C1-C2: C1: The real-time value of the q-axis voltage component is processed into its absolute value and its amplitude is dynamically calculated. Then, it is combined with the set exponent n for power calculation and compared with the scaling factor. Dividing them gives the damping coefficient at the current moment.

[0057] C2: The damping coefficient obtained by dynamic calculation is used as the time constant parameter in the inertia control filter to update the calculation logic of the inertia control channel in real time.

[0058] Specifically, the relationship between the absolute value of the q-axis voltage component and the damping coefficient is expressed by the formula: in, Expressed as the damping coefficient, Represented as a scaling factor, It is represented as the q-axis voltage component.

[0059] Furthermore, in step S4, obtaining the target instruction value for the next moment includes the following steps D1-D3: D1: Obtain two types of instruction values: the first type of instruction value is the additional torque or active power instruction output by the inertia response channel; the second type of instruction value is the basic power or torque reference value generated by the wind turbine main control link.

[0060] D2: Merge the first type of instruction value and the second type of instruction value to construct a unified target instruction value for the current control cycle.

[0061] D3: The unified target command value is used as the target power or torque reference signal for the current control cycle and input into the PI controller to drive the rotor excitation voltage output.

[0062] In this embodiment of the application, step D2, the fusion process adopts a fixed-weighted fusion method, including the following steps D211-D213: D211: Set two fixed proportional coefficients, which correspond to the weights of the inertia response command and the main control command, respectively, for example, 0.3 and 0.7.

[0063] D212: Linearly weights and synthesizes the two command values ​​according to the set weights to obtain the target power or torque command value.

[0064] D213: Sets upper and lower limits for the synthesis results to prevent the output from exceeding the capacity boundaries of the wind turbine or converter.

[0065] In an optional implementation, the fusion process may also employ a perturbation-sensitive adaptive fusion method, including the following steps D221-D223: D221: Real-time monitoring of the degree of power grid disturbance, which can be quantified by the absolute value of the q-axis voltage component or its rate of change.

[0066] D222: Dynamically adjust the weighting factor according to the strength of the disturbance. For example, increase the weight of the inertial response command when the disturbance is strong, and use the main control command when the disturbance is weak.

[0067] D223: Apply the adjusted weights to the fusion of the two instruction values ​​and set a limiting logic to ensure a reasonable output.

[0068] In another alternative implementation, the fusion process may also employ a perturbation-sensitive adaptive fusion method, including the following steps D231-D233: D231: Set the frequency deviation threshold or disturbance trigger threshold as a criterion input.

[0069] D232: When the disturbance is greater than the threshold, the main control command is temporarily blocked and only the inertia response command is output; when the disturbance is less than the threshold, only the main control command is output and the inertia response channel is ignored.

[0070] D233: Add a transition filter or dead-time control during instruction switching to avoid output jumps or system oscillations caused by frequent switching.

[0071] It should be noted that the PI controller can eliminate steady-state errors and accelerate transient response, enabling the dq-axis current control target to be achieved more quickly, thereby improving the dynamic characteristics of the wind turbine's torque and power output. Based on the dq-axis current control structure, the active and reactive power channels are effectively decoupled, and the three-phase signal generated by the inverse transformation can accurately drive the rotor converter, avoiding the influence of coupling errors. The voltage reference value output by this scheme can be flexibly connected to various driving mechanisms such as PWM and DTC, which is beneficial to the scalability of subsequent control chains.

[0072] Furthermore, in step S5, controlling the output of the doubly-fed wind turbine includes the following steps E1-E3: E1: Based on the target power or torque command value, construct control paths in the d-axis and q-axis directions respectively, and use a proportional-integral controller to calculate the reference values ​​of the d-axis excitation voltage and the q-axis excitation voltage.

[0073] E2: Input the obtained d-axis and q-axis excitation voltage reference values ​​into the inverse transformation module in the synchronous rotating coordinate system. Combined with the instantaneous grid phase angle output by the phase-locked loop PLL, perform the inverse transformation from the rotating coordinate to the three-phase stationary coordinate to obtain the three-phase excitation voltage command value.

[0074] E3: Input the three-phase excitation voltage reference value obtained by inverse coordinate transformation to the converter, and convert it into a control signal for driving the power switching devices of the rotor-side converter.

[0075] In this embodiment of the application, in step E3, the control signal is generated using a pulse width modulation (PWM)-based drive signal generation method, including the following steps E311-E313: E311: Input the three-phase excitation voltage reference value obtained by the inverse transformation of the dq coordinates to the PWM modulator.

[0076] E312: The PWM modulator generates a triangular wave at a set fixed carrier frequency and compares the reference value of each phase voltage with the triangular wave to obtain the gate pulse signal.

[0077] E313: The generated gate pulse signal is applied to the three-phase power switching devices (such as IGBTs) in the rotor-side converter to control the output voltage waveform and meet the target command.

[0078] Specifically, the control signal is calculated as follows: Torque command value and rotor current d-axis component reference value They are approximately equal, therefore the reference value of the d-axis component of the rotor current and the rotor current are... The d-axis component of the excitation voltage is obtained after PI control. The input-output relationship is as follows: in, This represents the proportional coefficient for d-axis current control. This represents the integral coefficient for d-axis current control. Represented as the Laplace operator, This is expressed as a reference value for total torque. It is represented as the additional torque value calculated by the inertia control channel.

[0079] For reactive power reference value and reactive power After PI control, the reference value of the q-axis component of the rotor current is obtained. The PI controller includes a proportional gain for the reactive power control channel. and integral coefficient for reactive power control channel In a real system, these two parameters need to be adjusted according to the actual situation of the system. The relationship between input and output is as follows: Reference value for the q-axis component of rotor current With rotor current The q-axis component of the excitation voltage is obtained after PI control. The input-output relationship is as follows: in, This represents the proportional coefficient for q-axis current control. This is represented as the integral coefficient for q-axis current control.

[0080] For the d-axis component of the excitation voltage and excitation voltage q-axis component The drive signal of the converter is obtained after calculation in the phase-locked coordinate system. The control drive signal of the doubly-fed induction generator converter is calculated using the following formula: in, , , They are respectively represented as Phase A control drive signal, Phase B control drive signal, Phase C control drive signal This represents the total excitation voltage amplitude before the transformation. This is expressed as the instantaneous angular velocity of the power grid output by the phase-locked loop (PLL). It is expressed as the mechanical angular velocity of the wind turbine rotor.

[0081] In an optional implementation, the control signal can also be generated using a drive signal generation method based on space vector pulse width modulation (SVPWM), including the following steps E321-E323: E323: Converts the three-phase excitation voltage reference value into the position of the equivalent voltage vector in a two-dimensional plane coordinate system.

[0082] E323: Calculate the sector in which the vector is located based on its position, and solve for the action time of the two adjacent basic space vectors and the zero vector time.

[0083] E323: Recombines the action times of each phase vector to generate a three-phase SVPWM pulse sequence, which is used to drive the three-phase bridge arms of the converter to achieve higher voltage utilization and lower harmonic content.

[0084] In another alternative implementation, the control signal can also be generated using a drive signal generation method based on direct torque control (DTC), including the following steps E331-E333: E331: Based on the voltage reference value, the current flux linkage and torque state are inferred, and the actual rotor flux linkage vector is estimated using the flux linkage model.

[0085] E332: Compare the actual flux linkage state with the target torque and flux linkage, and select the appropriate combination of switching states using a lookup table or hysteresis comparator.

[0086] E333: Directly outputs converter switching signals without the need for a pulse width modulator, enabling fast and direct control of the converter. It is suitable for disturbance suppression scenarios with high requirements for response speed.

[0087] It should be noted that this step employs pulse width modulation (PWM) and other methods to improve voltage utilization and reduce harmonics, thereby enhancing grid-connected power quality. Using modulator-free methods such as DTC allows direct control of the switching state, suitable for control scenarios requiring rapid response to frequency fluctuations. Different signal generation methods can be switched according to the operating state, ensuring efficient control capabilities even under complex conditions such as low voltage ride-through, inertial response, or frequency disturbances.

[0088] Example 3, referring to Figure 2 and Figure 3 This is the third embodiment of the present invention, which differs from the previous two embodiments in that: a system for adaptively improving inertial response and frequency damping based on phase-locked error includes an error acquisition module, a command value output module, an adjustment module, a command value superposition module, and a control module; the error acquisition module acquires the phase-locked error of the wind turbine at the current moment, and the phase-locked error is characterized by the q-axis voltage component obtained by coordinate transformation of the three-phase voltage signal at the grid connection point; the command value output module inputs the q-axis voltage component into the inertia control loop to obtain the additional torque or active power command value; the adjustment module adaptively adjusts the damping coefficient T based on the absolute value of the q-axis voltage component; the command value superposition module superimposes the additional torque or active power command value with the active power or torque command values ​​generated by other loops to obtain the target command value for the next moment; the control module calculates the d-axis and q-axis reference components of the excitation voltage through a proportional-integral controller according to the target command value, and generates the control signal of the rotor-side converter through inverse coordinate transformation to control the output of the doubly-fed wind turbine.

[0089] This embodiment will compare the traditional technical solution with the method of the present invention through testing, using scientific methods to compare the experimental results, in order to verify the actual effect of the method. Figure 2 As can be seen, after a disturbance occurs, the inertial control based on this invention exhibits a significantly faster response speed than traditional inertial control, and its amplitude is also larger under the same parameters. Furthermore, from... Figure 3 As shown in the system frequency diagram, the rate of frequency change at the initial moment is significantly smaller, which is beneficial to system stability. Therefore, it can be demonstrated that the adaptive control based on phase-locked loop error of this invention has superiority.

[0090] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0091] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0092] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0093] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented in combination with any of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0094] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for adaptively improving inertial response and frequency damping based on phase-locked loop error, characterized in that: include, The phase-locked error of the wind turbine at the current moment is obtained. The phase-locked error is characterized by the q-axis voltage component obtained by coordinate transformation of the three-phase voltage signal at the grid connection point. The q-axis voltage component is input into the inertia control loop to obtain the additional torque or active power command value. The damping coefficient T is adaptively adjusted based on the absolute value of the q-axis voltage component; The additional torque or active power command value is superimposed with the active power or torque command values ​​generated by other links to obtain the target command value at the next moment. Based on the target command value, the d-axis and q-axis reference components of the excitation voltage are calculated by a proportional-integral controller, and the control signal of the rotor-side converter is generated by inverse coordinate transformation to control the output of the doubly-fed wind turbine.

2. The method for adaptively improving inertial response and frequency damping based on phase-locked loop error as described in claim 1, characterized in that: The phase-locked error is characterized by the q-axis voltage component obtained by coordinate transformation of the three-phase voltage signal at the grid connection point, including... The three-phase voltage signal at the grid connection point is collected and represented using three-phase stationary coordinates. Based on the grid connection point voltage signal and the instantaneous reference phase angle obtained by the phase-locked loop, a mapping relationship between three-phase stationary coordinates and two-dimensional stationary coordinates is constructed. Using two-dimensional stationary coordinates and instantaneous reference phase angle as inputs, the Parker transformation is used to convert the quantities in the stationary coordinate system into d-axis and q-axis components in the synchronous rotating coordinate system. The obtained q-axis component is bandpass filtered to remove residual high-frequency components, and the filtered q-axis component is used as the q-axis voltage component. The d-axis is the direct axis in a doubly-fed induction motor for wind power, used to represent the excitation component; the q-axis is the quadrature axis in a doubly-fed induction motor for wind power, representing the dynamic part of the output torque or current.

3. The method for adaptively improving inertial response and frequency damping based on phase-locked loop error as described in claim 2, characterized in that: The obtained additional torque or active power command value includes, The q-axis component is input to the inertia control channel as a characterization of the system frequency change rate, reflecting the current degree of power grid disturbance. An inertia response adjustment channel is constructed based on the q-axis voltage component, and the active power or torque reference for inertia compensation is extracted to calculate the additional torque or active power command value.

4. The method for adaptively improving inertial response and frequency damping based on phase-locked loop error as described in claim 3, characterized in that: Adaptive adjustment of the damping coefficient T based on the absolute value of the q-axis voltage component includes: The real-time value of the q-axis voltage component is processed by absolute value and the amplitude is dynamically calculated. Then, it is combined with the set exponent n for power calculation and compared with the scaling factor. Divide the two to obtain the damping coefficient at the current moment; The damping coefficient obtained by dynamic calculation is used as the time constant parameter in the inertia control filter to update the calculation logic of the inertia control channel in real time.

5. The method for adaptively improving inertial response and frequency damping based on phase-locked loop error as described in claim 4, characterized in that: The relationship between the absolute value of the q-axis voltage component and the damping coefficient is expressed by the formula: in, Expressed as the damping coefficient, Represented as a scaling factor, It is represented as the q-axis voltage component.

6. The method for adaptively improving inertial response and frequency damping based on phase-locked loop error as described in claim 5, characterized in that: The process of obtaining the target instruction value for the next moment includes, Two types of command values ​​are obtained respectively: the first type of command value is the additional torque or active power command output by the inertial response channel; The second type of instruction value is the basic power or torque reference value generated by the main control link of the wind turbine. The first type of instruction value and the second type of instruction value are fused together to construct a unified target instruction value for the current control cycle; The unified target command value is used as the target power or torque reference signal for the current control cycle and input into the PI controller to drive the rotor excitation voltage output.

7. The method for adaptively improving inertial response and frequency damping based on phase-locked loop error as described in claim 6, characterized in that: The control output of the doubly fed wind turbine includes, Based on the target power or torque command value, control paths are constructed in the d-axis and q-axis directions respectively, and the reference values ​​of d-axis excitation voltage and q-axis excitation voltage are calculated using a proportional-integral controller; The obtained d-axis and q-axis excitation voltage reference values ​​are input to the inverse transformation module in the synchronous rotating coordinate system. Combined with the instantaneous grid phase angle output by the phase-locked loop PLL, the inverse transformation from the rotating coordinate to the three-phase stationary coordinate is performed to obtain the three-phase excitation voltage command value. The reference value of the three-phase excitation voltage obtained by inverse coordinate transformation is input to the converter and converted into a control signal for driving the power switching devices of the rotor-side converter.

8. A system for adaptively improving inertial response and frequency damping based on phase-locked loop error, employing the method for adaptively improving inertial response and frequency damping based on phase-locked loop error as described in any one of claims 1 to 7, characterized in that: It includes an error acquisition module, an instruction value output module, an adjustment module, an instruction value superposition module, and a control module; The error acquisition module acquires the phase-locked error of the wind turbine at the current moment. The phase-locked error is characterized by the q-axis voltage component obtained by coordinate transformation of the three-phase voltage signal at the grid connection point. The command value output module inputs the q-axis voltage component into the inertia control loop to obtain the additional torque or active power command value. The adjustment module adaptively adjusts the damping coefficient T based on the absolute value of the q-axis voltage component; The command value superposition module superimposes the additional torque or active power command value with the active power or torque command values ​​generated by other links to obtain the target command value at the next moment. The control module calculates the d-axis and q-axis reference components of the excitation voltage using a proportional-integral controller based on the target command value, and generates the control signal for the rotor-side converter through inverse coordinate transformation to control the output of the doubly-fed wind turbine.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of any one of claims 1 to 7 of the method for adaptively improving inertial response and frequency damping based on phase-locked error.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of any one of claims 1 to 7 of the method for adaptively improving inertial response and frequency damping based on phase-locked error.

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