Method, system, device and medium for multi-modal oscillation suppression based on damping cooperative control

Abstract

The embodiment of the application provides a kind of based on the method, system, equipment and medium of multi-modal oscillation suppression of damping coordination control, belong to the field of coordination control new energy station inside different output characteristic inverter maintain system transient stability.It comprises: the multiple-node admittance matrix of multi-machine grid-connected system is constructed, one or more oscillation modes of multi-machine grid-connected system is identified based on multiple-node admittance matrix, and the participation factor of each unit under each oscillation mode is determined;According to its quantitative contribution degree of each unit to corresponding oscillation mode, determine the responsibility weight of each unit in damping coordination control based on it;Reconstruction damping distribution coefficient, and it is mapped to the additional damping control parameter of each unit;Adjust the additional signal of injection inverter control loop, realize the coordinated suppression of multi-modal oscillation of multi-machine grid-connected system.The precise quantification and differentiated distribution of the damping responsibility of each unit are realized, so that it dynamically coordinates the damping resource of each unit, suppresses wideband multi-modal oscillation under multiple working conditions.

Description

Technical Field

[0001] This invention relates to the field of technology for maintaining transient stability of inverters with different output characteristics in new energy power plants through coordinated control, and specifically to a method, system, device and medium for suppressing multimodal oscillations based on damped coordinated control. Background Technology

[0002] Large-scale distributed generation systems rely on a large number of power electronic inverters operating in parallel with the grid. Due to differences in the control parameters and electrical characteristics of each inverter, multiple inverters form complex coupling interactions through grid impedance, which can easily induce multimode oscillations over a wide frequency range, leading to system stability issues. Currently, research on damping control strategies for single-type inverters is relatively mature. However, in the coordinated grid operation of multiple inverters with significantly different output characteristics in new energy power plants, the transient stability of the system becomes more complex. Damping control strategies based solely on a single-unit dimension are insufficient to dynamically coordinate and adjust the output characteristics of each inverter in a multi-unit grid-connected system at the system level, making it difficult to achieve overall coordinated damping optimization under complex operating conditions.

[0003] To address the multimodal oscillation suppression problem in multi-inverter grid-connected systems, existing research often employs control strategies such as averaging the control target or adding damping to weaker units. However, these methods fail to adequately consider the impact of impedance coupling between different units on the average damping allocation strategy, and also neglect the issue that changes in operating conditions may cause the installation point of the additional damping controller to deviate from its optimal position, thus failing to achieve the best overall damping effect for the power plant. Therefore, how to construct a multi-unit damping collaborative control strategy for new energy power plants, and coordinate the dynamic output characteristics of each inverter to ensure stable system operation under different operating conditions and topology changes, has become a critical problem that urgently needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a method, system, device, and medium for suppressing multimodal oscillations based on damping cooperative control, aiming to solve the problem that the existing damping control strategies have limited multimodal oscillation suppression effects due to the lack of system-level coordination and the failure to reasonably allocate damping responsibilities among units. To achieve the above objectives, embodiments of the present invention provide a multimodal oscillation suppression method based on damped cooperative control, comprising: Construct a multi-node admittance matrix for a multi-unit grid-connected system, identify one or more oscillation modes of the multi-unit grid-connected system based on the multi-node admittance matrix, and determine the participation factor of each unit under each oscillation mode; Based on the participation factors of each unit under each oscillation mode, the contribution of each unit to the corresponding oscillation mode is quantified, and the responsibility weight of each unit in the damping coordinated control is determined based on the contribution level. A damping allocation coefficient is constructed based on the responsibility weight, and the damping allocation coefficient is mapped to the additional damping control parameters of each unit; Each unit adjusts the additional signal injected into the inverter control loop according to its own corresponding additional damping control parameters to achieve coordinated suppression of multi-mode oscillations in the multi-unit grid-connected system.

[0005] Optionally, identifying one or more oscillation modes of the multi-machine grid-connected system based on the multi-node admittance matrix includes: Based on the aggregate impedance model of a multi-machine grid-connected system, the oscillation risk frequency of the system is screened using the closed-loop transfer function pole criterion, and the oscillation risk frequency is used as the initial search point of the system characteristic equation. Construct the equivalent multi-node network admittance matrix of the multi-machine grid-connected system from the AC side port, obtain the eigenvalues ​​of system convergence through numerical iteration, and identify the eigenvalues ​​as the oscillation modes of the multi-machine grid-connected system.

[0006] Optionally, determine the participation factors of each unit under each oscillation mode, including: Substitute the eigenvalues ​​corresponding to the target oscillation mode into the node admittance matrix for decomposition, and use the relationship between the matrix eigenvalues ​​and the determinant to establish the correspondence between the system eigenvalues ​​and the maximum mode impedance; Based on the aforementioned correspondence, and combined with the left and right eigenvectors obtained from the decomposition of the node admittance matrix, the degree of participation of each unit in the target oscillation mode at the common coupling point is calculated, and the degree of participation is used as the participation factor.

[0007] Optionally, based on the participation factors of each unit under each oscillation mode, the contribution of each unit to the corresponding oscillation mode is quantified, including: The participation factors of each unit under the target oscillation mode are normalized to obtain the relative contribution of each unit to the target oscillation mode; Units that meet the preset contribution requirements in terms of relative contribution are identified as units bearing primary responsibility for damping. The remaining units, excluding those bearing primary responsibility for damping, have their respective damping responsibility weights determined based on the ratio of their relative contribution to that of the primary responsible unit.

[0008] Optionally, each unit may use its own additional damping control parameters, including: grid-connected voltage additional damping control parameters for reshaping the impedance characteristics in the low-to-medium frequency range, and capacitor current active damping control parameters for reshaping the impedance characteristics in the low-to-medium frequency range.

[0009] Optionally, mapping the damping distribution coefficient to the additional damping control parameters of each unit includes: Predetermine the target grid-connected voltage additional damping setting value and the target capacitor current active damping setting value of the main responsible unit; Based on the target grid-connected voltage additional damping setting value and the target capacitor current active damping setting value of the main responsible unit, the grid-connected voltage additional damping control parameters and capacitor current active damping control parameters of each unit are calculated proportionally according to the damping distribution coefficient of each unit. Optionally, each unit adjusts the additional signal injected into the inverter control loop according to its corresponding additional damping control parameters to achieve coordinated suppression of multi-mode oscillations in the multi-unit grid-connected system, including: The additional damping control parameters are mapped to the voltage additional signal channel and capacitor current additional signal channel of the inverter inner loop of each unit, respectively. By adjusting the magnitude of the injected voltage and capacitor current additional signals, the output impedance characteristics of each unit are reshaped in a coordinated manner to suppress the oscillation modes of the system in different frequency bands. Secondly, the present invention also provides a multimodal oscillation suppression system based on damped cooperative control, comprising: The modal identification module is used to construct the multi-node admittance matrix of the multi-machine grid-connected system, identify one or more oscillation modes of the system based on the multi-node admittance matrix, and determine the participation factor of each unit under each oscillation mode. The weight allocation module is used to quantify the contribution of each unit to the corresponding oscillation mode according to the participation factor of each unit under each oscillation mode, and determine the responsibility weight of each unit in the damping coordinated control based on the contribution level. The parameter mapping module is used to construct damping allocation coefficients based on the responsibility weights and map the damping allocation coefficients to the additional damping control parameters of each unit. The collaborative suppression module is used to enable each unit to adjust the additional signal injected into the inverter control loop according to its own corresponding additional damping control parameters, so as to achieve collaborative suppression of multi-mode oscillations in multi-machine systems.

[0010] Thirdly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the multimodal oscillation suppression method based on damping cooperative control described above.

[0011] Fourthly, the present invention also provides a storage medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the multimodal oscillation suppression method based on damping cooperative control described above.

[0012] By constructing a multi-node admittance matrix to identify oscillation modes and quantify the participation factors of each unit, the above technical solution achieves accurate quantification and differentiated allocation of damping responsibilities of each unit at the system level. The allocation results are then mapped to additional damping control parameters, thereby overcoming the shortcomings of traditional average allocation or single-unit additional damping strategies that lack system coordination. This achieves the technical effect of dynamically coordinating the damping resources of each unit under multiple operating conditions and effectively suppressing broadband multimodal oscillations.

[0013] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of a multimodal oscillation suppression method based on damped cooperative control provided by an embodiment of the present invention; Figure 2 This is a single-machine main circuit and current inner loop control topology diagram provided in an embodiment of the present invention; Figure 3 This is a flowchart of a dual-machine grid-connected aggregation analysis method provided in an embodiment of the present invention; Figure 4 This is one of the embodiments provided by the present invention. Figure showing the evaluation results of oscillation modes and the participation of each machine; Figure 5 This is one of the embodiments provided by the present invention. Figure showing the evaluation results of oscillation modes and the participation of each machine; Figure 6 This is one of the embodiments provided by the present invention. Figure showing the evaluation results of oscillation modes and the participation of each machine; Figure 7 This is one of the embodiments provided by the present invention. Figure showing the evaluation results of oscillation modes and the participation of each machine; Figure 8 This is one of the embodiments provided by the present invention. Figure showing the evaluation results of oscillation modes and the participation of each machine; Figure 9 This is a single-machine current inner loop structure diagram of a broadband impedance reshaping method based on grid-connected voltage additional damping and capacitor current active damping to reshape the impedance characteristics of a multi-machine grid-connected system at different frequency bands, provided by an embodiment of the present invention. Figure 10 This is an embodiment of the present invention providing a type A unit setting parameter. Change diagram; Figure 11 This is a type B unit setting parameter provided in an embodiment of the present invention. Change diagram; Figure 12 This is a control architecture diagram for the collaborative suppression of multimodal oscillations in a multi-machine system provided by an embodiment of the present invention; Figure 13 This is an impedance characteristic analysis diagram provided by an embodiment of the present invention, showing how damping responsibilities are allocated among different generating units according to a collaborative algorithm. Figure 14 This is an impedance characteristic analysis diagram of the average distribution of damping responsibility among various generating units provided in an embodiment of the present invention; Figure 15 This is a comparison diagram of the effects of single-machine additional damping and multi-machine damping coordinated control provided by an embodiment of the present invention; Figure 16 This is a schematic diagram of a multimodal oscillation suppression system based on damping cooperative control provided in an embodiment of the present invention; Figure 17 This is a schematic diagram of the hardware structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0015] Various embodiments of this disclosure will be described more fully in the following detailed description. This disclosure may have various embodiments, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of this disclosure to the specific embodiments disclosed herein, but rather this disclosure should be understood to cover all adjustments, equivalents, and / or alternatives falling within the spirit and scope of the various embodiments of this disclosure.

[0016] In the following, the terms “comprising” or “may include”, which may be used in various embodiments of this disclosure, indicate the presence of the disclosed functions or operations and do not limit the addition of one or more functions or operations. Furthermore, as used in various embodiments of this disclosure, the terms “comprising,” “having,” and their cognates are intended only to indicate a specific feature, number, step, operation, or combination of the foregoing and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, or combinations of the foregoing, or the possibility of adding one or more features, numbers, steps, operations, or combinations of the foregoing.

[0017] In various embodiments of this disclosure, the expression "or" or "at least one of A and / or B" includes any combination or all combinations of the words listed simultaneously. For example, the expression "A or B" or "at least one of A and / or B" may include A, may include B, or may include both A and B.

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] See Figure 1 The diagram shows a flowchart of a multimodal oscillation suppression method based on damped cooperative control in a specific embodiment, including the following execution steps: Step 100: Construct the multi-node admittance matrix of the multi-machine grid-connected system, identify one or more oscillation modes of the multi-machine grid-connected system based on the multi-node admittance matrix, and determine the participation factor of each unit under each oscillation mode.

[0020] Specifically, when identifying one or more oscillation modes of a multi-machine grid-connected system based on the multi-node admittance matrix in step 100, the following steps can be performed: S1000: Based on the aggregated impedance model of a multi-machine grid-connected system, the oscillation risk frequency of the system is screened using the closed-loop transfer function pole criterion, and the oscillation risk frequency is used as the initial search point of the system characteristic equation.

[0021] Specifically, the single-machine main circuit and current inner loop control topology are as follows: Figure 2 As shown, the mathematical model expression for the output admittance of the TITO inverter considering the frequency coupling effect, established using the harmonic linearization method, is as follows:

[0022] in, , , , The expression is as follows:

[0023]

[0024] In the formula, Indicates frequency as The positive sequence disturbance current with frequency is The influence of the positive sequence response voltage; Indicates frequency as The positive sequence disturbance current with frequency is The influence of negative sequence response voltage; Indicates frequency as The negative sequence disturbance current with frequency is The influence of the positive sequence response voltage; Indicates frequency as The negative sequence disturbance current with frequency is The influence of negative sequence response voltage. This represents the Laplace frequency domain operator, which is equivalent to the Laplace frequency domain operator in this frequency domain modeling. , The frequency of the disturbance current. The frequency shift of the Laplace frequency domain operator caused by inverter structural asymmetry can be equivalently represented in this frequency domain modeling as... ,in , The fundamental frequency, i.e. . , is the transfer function expression between the output angle of the phase-locked loop and the q-axis component of the input grid-connected current; where The transfer function for the phase-locked loop is expressed as follows: , This is the transfer function for the inner current loop current feedback. , These are the expressions for the static operating point on the d-axis and q-axis, respectively. , , It is the capacitor current in the simulation model. It is the conjugate of the capacitor current. α is the grid-connected current, and α is the phase difference between the grid-connected voltage and the grid-connected current. All these values ​​are obtained from FFT measurements in the actual simulation model. ;in =50Hz, the physical meaning of which is the fundamental angular frequency; grid voltage The value is 310V; mains inductance 3mH; DC voltage of the power grid The voltage is set to 700V; the rated output power of the grid is 10kW. Inverter-side inductor... The inverter filter capacitor is 3mH. The inverter grid-side inductor is 12μF. The current is 0.5mH. Control system parameters include: current loop parameters. They are 4 / 100 respectively; PLL parameters The values ​​are 1.72 / 492 respectively; PWM pulse width modulation gain The value is 0.5; the decoupling coefficient of the inner current loop dq axis is set. The gain is 0.0027; to improve system stability, the capacitor current feedback gain is... Configured to 10.

[0025] Dual-machine grid-connected aggregation analysis method such as Figure 3As shown, the steps are as follows: Step 1: Combine the grid-side inductance and the equivalent inductance of the transformer and transmission line; Step 2: Solve for the output impedance of a single unit as seen from the common coupling point; Step 3: Equivalent circuit diagram of multiple units connected in parallel to the grid; Step 4: Summate the positive-sequence admittance; Step 5: Summate the negative-sequence coupled voltage controlled current source; Step 6: Summate the positive-sequence disturbance voltage controlled current source; Step 7: Summate the negative-sequence coupled admittance. Extending this to a multi-unit grid-connected system, the multi-unit grid-connected aggregated impedance model is shown below:

[0026] Based on the generalized Nyquist criterion, the hysteresis matrix of a multi-machine grid-connected system is shown in the following equation:

[0027] In the formula, For grid admittance, where , It is the inductance of the power grid. for grid admittance The expression for the closed-loop transfer function of the multi-machine grid-connected system is shown in the following equation:

[0028] Oscillation risk frequency measurement standard To identify all frequency points in the new energy power station system that pose an oscillation risk.

[0029] S1001: Construct the equivalent multi-node network admittance matrix of the multi-machine grid-connected system as seen from the AC side port, obtain the eigenvalues ​​of system convergence through numerical iteration, and identify the eigenvalues ​​as the oscillation modes of the multi-machine grid-connected system.

[0030] In one specific implementation, determining the participation factor of each unit under each oscillation mode includes the following steps: S1: Substitute the eigenvalues ​​corresponding to the target oscillation mode into the node admittance matrix for decomposition, and use the relationship between the matrix eigenvalues ​​and determinants to establish the correspondence between the system eigenvalues ​​and the maximum mode impedance.

[0031] Specifically, the positive-order and negative-order node admittance matrices are obtained from the multi-node network as shown in the following formula:

[0032]

[0033] The expressions for controlled current sources in positive and negative sequence impedance network diagrams, derived from the definition of coupling impedance, are shown below:

[0034] In the formula, For coupling frequency voltage The resulting coupling frequency current, For the perturbation frequency voltage The resulting coupling frequency current, where the expressions for the positive and negative sequence coupling impedance matrices are as follows:

[0035]

[0036] The equivalent model of the system viewed from the AC side port is as follows:

[0037] The oscillation risk frequency obtained using the closed-loop transfer function stability criterion is taken as the initial value of the characteristic root, which is... To find all eigenvalues ​​of a multi-machine grid-connected system that satisfy the convergence condition. This refers to the oscillation mode of the system.

[0038] Furthermore, the oscillation mode Substitute them sequentially into the system node admittance matrix In the middle, the system node admittance matrix under different oscillation modes is analyzed. Decompose:

[0039] The right and left eigenvector matrices , The following formulas are shown respectively:

[0040]

[0041] It is the reciprocal of the eigenvalue The resulting diagonal matrix: .

[0042] S2: Based on the correspondence, and combined with the left and right eigenvectors obtained by decomposing the node admittance matrix, calculate the degree of participation of each unit in the target oscillation mode at the common coupling point, and use the degree of participation as the participation factor.

[0043] Specifically, the system eigenvalues ​​represent the matrix of system nodal admittances. The value whose determinant is zero, and the reciprocal of the characteristic roots. The presence of a maximum value indicates that the system is oscillating. Therefore, according to the determinant of the square matrix and the reciprocal of the system's characteristic roots... Relationship:

[0044] It can be seen that the characteristic roots of the oscillation mode Eigenvalues ​​corresponding to infinitesimals In the right and left eigenvector matrices , Find the reciprocals of the eigenvalues ​​in the diagonal matrix respectively. The corresponding right and left feature vectors. Combining them yields... The nodal voltage equations of the system under the oscillation mode are shown below:

[0045] This leads to the following equation showing the relationship between each unit and the common coupling point. The degree of participation of the oscillation mode was determined, and it was used as an important quantitative indicator for assessing the responsibility of each unit for system instability.

[0046] .

[0047] In one specific implementation, Figures 4-8 The assessment results of the responsibility of each unit for system instability under three typical scenarios are described. Figures 4-5 The increase is due to the number of units of the same type, as shown in Table 1. and ; Figure 4 The amplitude information corresponds to two different frequency points (0.19 Hz and 0.53 Hz). By comparing the amplitude response at the two different oscillation frequencies of 0.19 Hz and 0.53 Hz, the two values ​​are consistent, indicating that within the frequency band shown, the two oscillation frequencies have the same effect on the impedance amplitude. Figure 5 This diagram illustrates the oscillation modes of the system and the distribution of the participation factors (participation factors) of each unit in different modes under a grid-connected scenario with a 2:1 ratio of Type A to Type B units. The diagram identifies three main oscillation mode frequencies: 0.15Hz, 0.41Hz, and 0.57Hz. These frequencies correspond to the oscillation risks present in different frequency bands. In the 0.57Hz oscillation mode, the participation factors of A1 and A2 are both 0.25, significantly higher than B1's 0.02, indicating that Type A units contribute more to the oscillation in this mode and are the primary responsible units for damping control. In the 0.41Hz low-frequency mode, the participation factors of A1 and A2 are significantly higher than B1, indicating that low-frequency oscillations are mainly dominated by Type A units. In the 0.15Hz mid-frequency mode, the participation factors of each unit are relatively evenly distributed (0.24~0.27), indicating that the contribution levels of each unit are similar in this mode. Figures 6-7 The capacity ratios for different models are adjusted, as shown in Table 1. and ; Figure 6This indicates that when the number of units of types A and B is equal, the oscillation mode of the system expands from low frequency to medium and high frequency, and the oscillations in different frequency bands are dominated by different types of units, which provides a basis for damping allocation: low frequency oscillations should focus on type A units, and medium and high frequency oscillations should focus on type B units. Figure 7 This indicates that when the number of Type A units exceeds that of Type B units, low-frequency oscillations are mainly dominated by Type A units, but medium- and high-frequency oscillations still require Type B units to assume the main responsibility for damping. At the same time, Type A units also need to participate in the coordinated suppression, which reflects the necessity of multi-unit coordination. Figure 8 This refers to the connection of new types of generating units, as shown in Table 1. Three inverters with slightly different parameters were selected to simulate different unit types. Detailed parameters of the three inverters are shown in Table 2. Figure 8 This invention demonstrates the applicability of its method to grid-connected scenarios involving three or more different types of generating units. When a completely new type of inverter (C1) is introduced into the system, the number of modes and frequency distribution may change, but the participation factor analysis method proposed in this invention can still effectively identify the responsibility weight of each generating unit, providing support for multi-unit coordinated damping control.

[0048] Table 1: Combinations of Different Types of Generating Units

[0049] Table 2: Inverter Parameters

[0050] Step 101: Based on the participation factors of each unit under each oscillation mode, quantify the contribution of each unit to the corresponding oscillation mode, and determine the responsibility weight of each unit in the damping coordinated control based on the contribution level. Specifically, when executing step 101, the following steps can be performed: S1010: Normalize the participation factors of each unit under the target oscillation mode to obtain the relative contribution of each unit to the target oscillation mode.

[0051] Specifically, the normalization formula is shown below: .

[0052] S1011: Identify the units that meet the preset contribution requirements in the relative contribution as the units that bear the primary responsibility for damping. The remaining units, excluding the units that bear the primary responsibility for damping, determine their respective damping responsibility weights based on the ratio of their relative contribution to that of the primary responsible unit.

[0053] The unit with the highest relative contribution under the target oscillation mode is defined as the primary damping responsible unit. Damping responsibilities are allocated according to the participation of each unit relative to the primary responsible equipment, and the damping allocation coefficient is proposed as shown in the following formula: .

[0054] Step 102: Construct a damping allocation coefficient based on the responsibility weight, and map the damping allocation coefficient to the additional damping control parameters of each unit.

[0055] Specifically, each unit uses its own additional damping control parameters, including grid-connected voltage additional damping control parameters for reshaping the impedance characteristics in the low-to-medium frequency range, and capacitor current active damping control parameters for reshaping the impedance characteristics in the mid-to-high frequency range.

[0056] More specifically, when performing step 102, the following steps can be performed: S1020: Predetermine the target grid-connected voltage additional damping setting value and the target capacitor current active damping setting value of the main responsible unit.

[0057] S1021: Based on the target grid-connected voltage additional damping setting value and the target capacitor current active damping setting value of the main responsible unit, the grid-connected voltage additional damping control parameters and capacitor current active damping control parameters of each unit are calculated proportionally according to the damping distribution coefficient of each unit.

[0058] In one specific embodiment, the single-machine current inner loop structure of the broadband impedance reshaping method, which reshapes the impedance characteristics of a multi-machine grid-connected system at different frequency bands based on grid-connected voltage-added damping and capacitor current active damping, is as follows: Figure 9 As shown, the dashed box represents the introduced additional signal. The transfer function expression for the voltage signal feedback channel reshaping the impedance characteristics in the low-frequency band is as follows:

[0059] make , middle The key control parameters are .

[0060] The transfer function expression for the capacitor current signal feedback channel, which reshapes the impedance characteristics in the mid-to-high frequency band, is as follows:

[0061] Among them, the key control parameters are In the formula This refers to the center frequency of the high-frequency band during the operation of the notch filter. For notch filter quality factor, For capacitor current damping gain, Selecting the characteristic frequency of the mid-to-high frequency oscillation mode is... To concentrate the operating frequency band of the notch filter in the mid-to-high frequency range, the following selection method is used: .

[0062] Figures 10-11 Adding damping key control parameters to the grid connection voltage of different generating units The effect on the overall impedance characteristics of the system. Among them, Figure 10 The document outlines the optimization direction for phase frequency characteristics: as fp1 increases, the system's phase frequency characteristics shift in a direction favorable to stability, helping to reduce the range or extent of the negative damping region. The document also addresses the deterioration direction of phase frequency characteristics: when fp1 deviates from its optimal value, the phase frequency characteristics may shift in a deteriorating direction, leading to an expansion of the negative damping region or the addition of new oscillation risks. In the low-to-mid frequency band (inductive negative damping region): without control, the system exhibits inductive negative damping characteristics in this frequency band, with low impedance amplitudes and intersections with the grid impedance, posing an oscillation risk (see [reference]). Figure 10 The circle on the left indicates the oscillation-prone risk area. After implementing additional damping control, the impedance characteristics can be reshaped by adjusting the fp1 parameter, allowing it to avoid grid impedance in critical frequency bands, or increasing positive damping. Mid-to-high frequency band (capacitive negative damping region): Without control, the system exhibits capacitive negative damping characteristics in this frequency band, also posing an oscillation risk (see...). Figure 10 The oscillation risk zone is indicated by the circle in the middle. Voltage-added damping control is mainly for the low and medium frequency range, and its ability to regulate the mid and high frequency range is limited. It needs to be combined with capacitor current active damping to achieve full frequency coverage. Figure 11 In the direction of phase-frequency characteristic optimization, as fp1 increases, the phase shifts in a direction favorable to stability, and the negative damping region shrinks; in the direction of phase-frequency characteristic degradation, phase shift may lead to new oscillation risks (see...). Figure 11 In the diagram, the left and middle circles indicate the oscillation risk zones and oscillation risk zones, which require careful adjustment.

[0063] Step 103: Each unit adjusts the additional signal injected into the inverter control loop according to its corresponding additional damping control parameters to achieve coordinated suppression of multi-mode oscillations in the multi-unit grid-connected system.

[0064] Specifically, when executing step 103, the following steps can be performed: S1030: Map the additional damping control parameters to the voltage additional signal channel and capacitor current additional signal channel of the inner loop of each unit inverter, respectively.

[0065] Specifically, the damping allocation results are mapped to the active damping control parameters of the grid-connected voltage and capacitor current of each unit, as shown in the following formula:

[0066] in, and It is the optimal setting value for the main responsible unit.

[0067] S1031: By adjusting the magnitude of the injected voltage and capacitor current additional signals, the output impedance characteristics of each unit are reshaped in a coordinated manner to suppress the oscillation modes of the system in different frequency bands.

[0068] In one specific implementation, a control architecture for the coordinated suppression of multi-mode oscillations in a multi-machine system is achieved by adjusting the magnitude of the voltage and capacitor current-added signals injected into the inner loop of the inverter. Figure 12 As shown, firstly, based on the impedance models of each unit in a multi-unit grid-connected system, a system impedance matrix is ​​constructed. By solving the eigenvalues ​​of the impedance matrix, the oscillation modes present in the system are identified, including low-to-medium frequency oscillation modes and mid-to-high frequency oscillation modes. Secondly, for the identified key oscillation modes, the participation factor of each unit in this mode is calculated, quantifying the contribution of each unit to the oscillation mode. Based on this, a damping allocation mechanism is constructed to determine the damping responsibility weight of each unit. Finally, the damping allocation results are mapped to the additional damping control parameters of each unit. Through multi-unit coordinated control, unified suppression of oscillation modes in each frequency band is achieved, completing a complete closed loop from mode identification to damping coordinated control.

[0069] Table 3 shows the values ​​of the additional damping control parameters for each unit under different damping distribution strategies: Table 3: Values ​​of Additional Damping Control Parameters for Each Unit under Different Damping Distribution Strategies

[0070] Figures 13-14 The impedance characteristics of the system under different damping distribution strategies are compared and analyzed from the perspective of impedance. It is easy to see from the comparison and analysis results that the cooperative damping distribution strategy is better than the uniform distribution strategy in improving system stability.

[0071] Figure 13 The impedance characteristics of each unit in allocating damping responsibility according to the cooperative algorithm were analyzed and compared. Figure 14 The four corresponding to the middle (corresponding to the four in the middle respectively) Figure 14 From the positions indicated by the first group of arrows (to the positions indicated by the fourth group of arrows) from left to right, the impedance amplitude-frequency and phase-frequency characteristic observation points show that under the cooperative distribution strategy, the additional damping control parameters of each unit, under the influence of the damping distribution coefficient, differentially reshape the system impedance, optimizing the overall system impedance amplitude-frequency characteristics. Simultaneously, the phase-frequency characteristics change from the inductive and capacitive negative damping regions to the resistive-inductive region. In contrast, under the uniform damping distribution method, the overall system impedance amplitude-frequency characteristics deteriorate in the high-frequency range, and the phase-frequency characteristics change from resistive-capacitive to the inductive negative damping region; at the same time, the low-frequency phase-frequency characteristics deteriorate from resistive-inductive to resistive-capacitive, further exacerbating the system oscillation risk when the grid impedance increases. Therefore, cooperative damping distribution is superior to the uniform distribution strategy in improving system stability.

[0072] Figure 15 This is a comparison chart showing the effects of single-machine additional damping and multi-machine damping coordinated control. Figure 15 It can be seen that under different grid impedance conditions (L g =1e-3H、L g =3e-3H,L g =6e-3H), dual-machine damping coordinated control ( Figure 15 The lower and middle sections of the figure all show superior performance compared to single-machine control. Figure 15 The oscillation suppression situation (see the upper part of the figure). From... Figure 15 L g Under the condition of =1e-3H, the application of single-machine additional damping control and the application of dual-machine damping coordinated control ( Figure 15 (The part shown in the circle on the left) L g Under the condition of =3e-3H, the application of single-machine additional damping control and the application of dual-machine damping coordinated control ( Figure 15 (The part shown in the middle circle), L g Under the condition of =6e-3H, the application of single-machine additional damping control and the application of dual-machine damping coordinated control ( Figure 15 As shown in the circle on the right, compared with single-machine control, collaborative control can significantly reduce the oscillation amplitude and accelerate the oscillation decay speed. In particular, it can still achieve rapid stabilization under the condition of large grid impedance, indicating that multi-machine collaborative control can more effectively improve the overall damping level of the system.

[0073] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0074] The beneficial effects achieved by this invention are as follows: (1) This invention proposes a multi-unit collaborative damping control method based on modal analysis and participating factors. By constructing a multi-node admittance matrix model and combining it with eigenvalue analysis to identify system oscillation modes, a correspondence between oscillation modes and maximum modal impedance is established. Based on this, the responsibility of different units for system instability is quantitatively assessed, and a damping collaborative allocation mechanism is constructed accordingly. This method can characterize the dynamic impact of each unit on the oscillation modes at the system level, providing a basis for the rational allocation of damping resources in multi-unit grid-connected systems.

[0075] (2) Based on the aforementioned damping coordination allocation mechanism, this invention maps the damping allocation results to the additional damping control parameters of each unit. By adjusting the voltage and capacitor current additional signals injected into the inner loop of the inverter, the coordinated configuration of the damping control parameters of each unit is achieved. When the system operating conditions or oscillation modes change, this method can dynamically adjust the damping control parameters according to the unit's responsibility weight, thereby effectively suppressing oscillation modes in different frequency bands and improving the overall operational stability of the new energy power station.

[0076] like Figure 16 As shown, the following are embodiments of the multimodal oscillation suppression system based on damping cooperative control provided in this disclosure. These embodiments belong to the same inventive concept as the multimodal oscillation suppression methods based on damping cooperative control described above. For details not described in detail in the embodiments of the multimodal oscillation suppression system based on damping cooperative control, please refer to the embodiments of the multimodal oscillation suppression methods based on damping cooperative control described above.

[0077] A multimodal oscillation suppression system based on damped cooperative control includes: The modal identification module is used to construct the multi-node admittance matrix of the multi-machine grid-connected system, identify one or more oscillation modes of the system based on the multi-node admittance matrix, and determine the participation factor of each unit under each oscillation mode. The weight allocation module is used to quantify the contribution of each unit to the corresponding oscillation mode according to the participation factor of each unit under each oscillation mode, and determine the responsibility weight of each unit in the damping coordinated control based on the contribution level. The parameter mapping module is used to construct damping allocation coefficients based on the responsibility weights and map the damping allocation coefficients to the additional damping control parameters of each unit. The collaborative suppression module is used to enable each unit to adjust the additional signal injected into the inverter control loop according to its own corresponding additional damping control parameters, so as to achieve collaborative suppression of multi-mode oscillations in multi-machine systems.

[0078] Figure 17 This is a schematic diagram of the hardware structure of an electronic device that implements various embodiments of the present invention.

[0079] The multimodal oscillation suppression method based on damped cooperative control provided in this application embodiment can be applied to electronic devices. Those skilled in the art will understand that the electronic device structure involved in the embodiments of this invention does not constitute a limitation on the electronic device. An electronic device may include more or fewer components than illustrated, or combine certain components, or have different component arrangements. In the embodiments of this invention, the electronic device includes, but is not limited to, laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the embodiments of this application described and / or claimed herein.

[0080] Electronic devices may include processors, external memory interfaces, internal memory, universal serial bus (USB) interfaces, charging management modules, power management modules, batteries, wireless communication modules, audio modules, speakers, microphones, sensor modules, buttons, cameras, displays, and SIM card interfaces, etc.

[0081] It is understood that the structures illustrated in the embodiments of this application do not constitute a specific limitation on the electronic device. In other embodiments of this application, the electronic device may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0082] A processor may include one or more processing units, such as: a central processing unit (CPU), an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, memory, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural network processing unit (NPU). Different processing units may be independent devices or integrated into one or more processors.

[0083] The processor can serve as the nerve center and command center of an electronic device. The controller can generate operation control signals based on the instruction opcode and timing signals to control the fetching and execution of instructions.

[0084] The processor may also include memory for storing instructions and data. In some embodiments, the memory in the processor is a cache memory. This memory can store instructions or data that the processor has just used or that are used repeatedly. If the processor needs to use the instruction or data again, it can retrieve it directly from this memory. This avoids repeated accesses, reduces processor latency, and thus improves system efficiency.

[0085] An external storage interface (ESI) can be used to connect external memory cards, such as microSD cards, to expand the storage capacity of electronic devices. The external memory card communicates with the processor through the ESI to perform data storage functions, such as saving music and video files on the external memory card.

[0086] Internal memory can be used to store computer executable program code, which includes instructions. The processor executes various functional applications and data processing of electronic devices by running the instructions stored in internal memory. Internal memory can include a program storage area and a data storage area. Internal memory can include high-speed random access memory, and can also include non-volatile memory, such as at least one disk storage device, flash memory device, universal flash storage (UFS), etc.

[0087] Wireless communication functionality in electronic devices can be achieved through antennas, wireless communication modules, modem processors, and baseband processors.

[0088] Wireless communication modules can provide solutions for wireless communication applications in electronic devices, including wireless local area networks (WLANs) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), and infrared (IR) technologies.

[0089] Electronic devices can implement audio functions through audio modules, speakers, receivers, microphones, headphone jacks, and application processors.

[0090] Electronic devices can achieve shooting functions through ISPs, cameras, video codecs, GPUs, displays, and application processors.

[0091] Electronic devices can achieve display functions through GPUs, displays, and application processors.

[0092] A GPU is a microprocessor for image processing, connected to the display screen and application processor. GPUs are used to perform mathematical and geometric calculations for graphics rendering. A processor may include one or more GPUs, which execute program instructions to generate or modify display information.

[0093] A display screen is used to display images, videos, etc. A display screen includes a display panel.

[0094] The storage medium provided in this application stores a program product capable of implementing a multimodal oscillation suppression method based on damping cooperative control.

[0095] The multimodal oscillation suppression method based on damping cooperative control includes: constructing a multi-node admittance matrix for a multi-machine grid-connected system; identifying one or more oscillation modes of the system based on the multi-node admittance matrix and determining the participation factor of each unit under each oscillation mode; quantifying the contribution of each unit to the corresponding oscillation mode based on the participation factor of each unit under each oscillation mode, and determining the responsibility weight of each unit in damping cooperative control based on the contribution; constructing a damping allocation coefficient based on the responsibility weight, and mapping the damping allocation coefficient to the additional damping control parameters of each unit; and adjusting the additional signal injected into the inverter control loop according to its own corresponding additional damping control parameters to achieve cooperative suppression of multimodal oscillations in the multi-machine grid-connected system.

[0096] In some possible implementations, the subject matter of this disclosure, namely, a method and system for suppressing multimodal oscillations based on damping cooperative control, can be implemented as a program product comprising program code that, when run on a terminal device, causes the terminal device to perform the steps described in the "Exemplary Methods" section of this specification according to various exemplary embodiments of this disclosure.

[0097] The storage medium disclosed herein may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0098] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for suppressing multimodal oscillations based on damped cooperative control, characterized in that, include: Construct a multi-node admittance matrix for a multi-unit grid-connected system, identify one or more oscillation modes of the multi-unit grid-connected system based on the multi-node admittance matrix, and determine the participation factor of each unit under each oscillation mode; Based on the participation factors of each unit under each oscillation mode, the contribution of each unit to the corresponding oscillation mode is quantified, and the responsibility weight of each unit in the damping coordinated control is determined based on the contribution level. A damping allocation coefficient is constructed based on the responsibility weight, and the damping allocation coefficient is mapped to the additional damping control parameters of each unit; Each unit adjusts the additional signal injected into the inverter control loop according to its own corresponding additional damping control parameters to achieve coordinated suppression of multi-mode oscillations in the multi-unit grid-connected system.

2. The multimodal oscillation suppression method based on damped cooperative control according to claim 1, characterized in that, Identifying one or more oscillation modes of a multi-machine grid-connected system based on the multi-node admittance matrix includes: Based on the aggregate impedance model of a multi-machine grid-connected system, the oscillation risk frequency of the system is screened using the closed-loop transfer function pole criterion, and the oscillation risk frequency is used as the initial search point of the system characteristic equation. Construct the equivalent multi-node network admittance matrix of the multi-machine grid-connected system from the AC side port, obtain the eigenvalues ​​of system convergence through numerical iteration, and identify the eigenvalues ​​as the oscillation modes of the multi-machine grid-connected system.

3. The multimodal oscillation suppression method based on damped cooperative control according to claim 2, characterized in that, Determine the participation factors of each unit under each oscillation mode, including: Substitute the eigenvalues ​​corresponding to the target oscillation mode into the node admittance matrix for decomposition, and use the relationship between the matrix eigenvalues ​​and the determinant to establish the correspondence between the system eigenvalues ​​and the maximum mode impedance; Based on the aforementioned correspondence, and combined with the left and right eigenvectors obtained from the decomposition of the node admittance matrix, the degree of participation of each unit in the target oscillation mode at the common coupling point is calculated, and the degree of participation is used as the participation factor.

4. The multimodal oscillation suppression method based on damped cooperative control according to claim 1, characterized in that, Based on the participation factors of each unit under each oscillation mode, the contribution of each unit to the corresponding oscillation mode is quantified, including: The participation factors of each unit under the target oscillation mode are normalized to obtain the relative contribution of each unit to the target oscillation mode; Units that meet the preset contribution requirements in terms of relative contribution are identified as units bearing primary responsibility for damping. The remaining units, excluding those bearing primary responsibility for damping, have their respective damping responsibility weights determined based on the ratio of their relative contribution to that of the primary responsible unit.

5. The multimodal oscillation suppression method based on damped cooperative control according to claim 1, characterized in that, Each unit has its own additional damping control parameters, including: grid-connected voltage additional damping control parameters for reshaping the impedance characteristics in the low-to-medium frequency range, and capacitor current active damping control parameters for reshaping the impedance characteristics in the low-to-medium frequency range.

6. The multimodal oscillation suppression method based on damped cooperative control according to claim 5, characterized in that, Mapping the damping distribution coefficient to the additional damping control parameters of each unit includes: Predetermine the target grid-connected voltage additional damping setting value and the target capacitor current active damping setting value of the main responsible unit; Based on the target grid-connected voltage additional damping setting value and the target capacitor current active damping setting value of the main responsible unit, the grid-connected voltage additional damping control parameters and capacitor current active damping control parameters of each unit are calculated proportionally according to the damping distribution coefficient of each unit.

7. The multimodal oscillation suppression method based on damped cooperative control according to claim 1, characterized in that, Each generating unit adjusts the additional signal injected into the inverter control loop according to its corresponding additional damping control parameters to achieve coordinated suppression of multi-mode oscillations in the multi-unit grid-connected system, including: The additional damping control parameters are mapped to the voltage additional signal channel and capacitor current additional signal channel of the inverter inner loop of each unit, respectively. By adjusting the magnitude of the injected voltage and capacitor current additional signals, the output impedance characteristics of each unit are reshaped in a coordinated manner to suppress the oscillation modes of the system in different frequency bands.

8. A multimodal oscillation suppression system based on damped cooperative control, characterized in that, include: The modal identification module is used to construct the multi-node admittance matrix of the multi-machine grid-connected system, identify one or more oscillation modes of the system based on the multi-node admittance matrix, and determine the participation factor of each unit under each oscillation mode. The weight allocation module is used to quantify the contribution of each unit to the corresponding oscillation mode according to the participation factor of each unit under each oscillation mode, and determine the responsibility weight of each unit in the damping coordinated control based on the contribution level. The parameter mapping module is used to construct damping allocation coefficients based on the responsibility weights and map the damping allocation coefficients to the additional damping control parameters of each unit. The collaborative suppression module is used to enable each unit to adjust the additional signal injected into the inverter control loop according to its own corresponding additional damping control parameters, so as to achieve collaborative suppression of multi-mode oscillations in multi-machine systems.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the multimodal oscillation suppression method based on damping cooperative control as described in any one of claims 1 to 7.

10. A 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 the multimodal oscillation suppression method based on damping cooperative control as described in any one of claims 1 to 7.

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