Method for adaptive adjustment of control parameters of a networked interworking system and related device

Abstract

The application relates to the technical field of electrical engineering, and particularly provides a control parameter self-adaptive adjustment method for a follow-network type interconnected system and related devices. According to the output standard value of the follow-network type converter, the voltage loop proportional coefficient of the network-constructing type converter can be dynamically segmented and set to 5.5 p.u. or 50 p.u. In this way, the small disturbance stability of the follow-network type new energy-network-constructing type energy storage interconnected system can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical engineering, and particularly relates to a control parameter adaptive adjustment method of a follow-grid and construct-grid interconnected system and a related device. BACKGROUND

[0002] With large-scale grid-connected installation of wind and light new energy, the power system is undergoing extremely profound changes. The traditional power system with synchronous generators as the main power source is evolving into a new type of power system with high proportions of wind and light new energy and high proportions of power electronic devices (double-high characteristics). Power electronic devices have low inertia and weak anti-disturbance characteristics, and are difficult to effectively support the voltage and frequency of the power grid. The strength of the power grid is declining, and the stability of the power system is threatened.

[0003] New energy storage has a multi-dimensional supporting effect on the power system. With the further increase of the proportion of new energy, the strength of the power grid is further reduced, and the synchronous stability of the power system is greatly challenged. The supporting effect of new energy storage on the stability of the power system is put on the agenda. Although the new energy generation unit itself can also be grid-controlled, the energy storage unit can be centrally configured in the grid node. The supporting capacity of the centralized grid-type energy storage is stronger than that of the dispersed grid-type new energy.

[0004] In recent years, in order to maintain the voltage and frequency stability of the new energy station, the traditional new energy station containing only a single type of converter is gradually transitioning to a hybrid station containing follow-grid and construct-grid converters. The control interaction and coupling between a large number of heterogeneous new energy converters, the resonance instability risk of the new energy station is increasing.

[0005] The output fluctuation of the follow-grid new energy changes the system steady-state operating point, and further affects the small signal stability of the system. The new energy generation-construct-grid energy storage interconnected system has a resonance instability risk caused by the mismatch of control parameters. Therefore, the existing follow-grid new energy-construct-grid energy storage interconnected system has a small signal instability risk. SUMMARY

[0006] The present application aims to at least solve one of the above technical defects, especially the technical defect that the existing follow-grid new energy-construct-grid energy storage interconnected system has a small signal instability risk.

[0007] In a first aspect, an embodiment of the present application provides a control parameter adaptive adjustment method of a follow-grid and construct-grid interconnected system, the follow-grid and construct-grid interconnected system comprising a follow-grid converter and a construct-grid converter applied to a new energy station, and the method comprises:

[0008] obtaining an output per unit value of the follow-grid converter and a current voltage loop proportional coefficient of the construct-grid converter;

[0009] if the output unit value is less than 0.7 unit value, and the current voltage loop proportional coefficient is 5.5 unit value, then the voltage loop proportional coefficient of the grid-forming converter is kept as 5.5 unit value;

[0010] if the output unit value is greater than or equal to 0.7 unit value, and the current voltage loop proportional coefficient is 5.5 unit value, then the voltage loop proportional coefficient of the grid-forming converter is adjusted to 50 unit value;

[0011] if the output unit value is less than 0.6 unit value, and the current voltage loop proportional coefficient is 50 unit value, then the voltage loop proportional coefficient of the grid-forming converter is adjusted to 5.5 unit value;

[0012] if the output unit value is greater than or equal to 0.6 unit value, and the current voltage loop proportional coefficient is 50 unit value, then the voltage loop proportional coefficient of the grid-forming converter is kept as 50 unit value.

[0013] In some embodiments, the method further comprises:

[0014] if the output unit value is less than a first preset unit value, then the current loop proportional coefficient of the grid-following converter is set to 2.253; wherein the first preset unit value is greater than or equal to 0.7 unit value;

[0015] if the output unit value is greater than or equal to the first preset unit value, and less than or equal to 1 unit value, then the current loop proportional coefficient of the grid-following converter is set according to a target function expression obtained by pre-fitting;

[0016] wherein the target function expression is a function expression with the current loop proportional coefficient of the grid-following converter as the dependent variable, and the output unit value of the grid-following converter as the independent variable.

[0017] In some embodiments, the first preset unit value is 0.72 unit value.

[0018] In some embodiments, the target function expression is:

[0019]

[0020] wherein, is the output unit value of the grid-following converter, is the current loop proportional coefficient of the grid-following converter.

[0021] In a second aspect, the embodiments of the present application provide a device for adaptively adjusting control parameters of a grid-following and grid-forming interconnected system, the grid-following and grid-forming interconnected system comprising a grid-following converter and a grid-forming converter applied to a new energy station, and the device comprising:

[0022] an output acquisition module, configured to acquire an output per unit value of the grid-following converter and a current voltage loop proportional coefficient of the grid-forming converter;

[0023] a first coefficient adjustment module, configured to, if the output per unit value is less than 0.7 per unit value and the current voltage loop proportional coefficient is 5.5 per unit value, maintain the voltage loop proportional coefficient of the grid-forming converter as 5.5 per unit value;

[0024] a second coefficient adjustment module, configured to, if the output per unit value is greater than or equal to 0.7 per unit value and the current voltage loop proportional coefficient is 5.5 per unit value, adjust the voltage loop proportional coefficient of the grid-forming converter to 50 per unit value;

[0025] a third coefficient adjustment module, configured to, if the output per unit value is less than 0.6 per unit value and the current voltage loop proportional coefficient is 50 per unit value, adjust the voltage loop proportional coefficient of the grid-forming converter to 5.5 per unit value;

[0026] a fourth coefficient adjustment module, configured to, if the output per unit value is greater than or equal to 0.6 per unit value and the current voltage loop proportional coefficient is 50 per unit value, maintain the voltage loop proportional coefficient of the grid-forming converter as 50 per unit value.

[0027] In some embodiments, the device further comprises:

[0028] a fifth coefficient adjustment module, configured to, if the output per unit value is less than a first preset per unit value, set the current loop proportional coefficient of the grid-following converter to 2.253; wherein the first preset per unit value is greater than or equal to 0.7 per unit value;

[0029] a sixth coefficient adjustment module, configured to, if the output per unit value is greater than or equal to the first preset per unit value and less than or equal to 1 per unit value, set the current loop proportional coefficient of the grid-following converter according to a target function expression obtained by pre-fitting;

[0030] wherein the target function expression is a function expression with the current loop proportional coefficient of the grid-following converter as a dependent variable and the output per unit value of the grid-following converter as an independent variable.

[0031] In some embodiments, the first preset per unit value is 0.72 per unit value.

[0032] In some embodiments, the target function expression is:

[0033]

[0034] wherein, a power output unit of the grid-following converter, a current loop proportional coefficient of the grid-following converter.

[0035] In a third aspect, an embodiment of the present application provides a storage medium, the storage medium storing computer readable instructions, the computer readable instructions being executed by one or more processors to cause the one or more processors to perform the steps of the method for adaptively adjusting a control parameter of a grid-interconnected system according to any of the embodiments.

[0036] In a fourth aspect, an embodiment of the present application provides a computer device, the computer device comprising: one or more processors, and a memory;

[0037] The memory stores computer readable instructions, the computer readable instructions being executed by the one or more processors to perform the steps of the method for adaptively adjusting a control parameter of a grid-interconnected system according to any of the embodiments.

[0038] The technical scheme provided by the present application at least has the following technical effects:

[0039] The present application can dynamically segmentally set the voltage loop proportional coefficient of the grid-forming converter to 5.5 p.u. or 50 p.u. according to the power output unit of the grid-following converter. In this way, the small signal stability of the grid-following new energy-grid-forming energy storage interconnected system can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0041] Figure 1 a position relationship diagram of a control system coordinate system and a grid coordinate system when a phase angle small disturbance occurs;

[0042] Figure 2 an admittance sweep measurement result of applying a 1-1000 Hz frequency small disturbance voltage at a grid-connected point of the grid;

[0043] Figure 3 an impedance sweep measurement result of applying a 1-1000 Hz frequency small disturbance voltage at a grid-connected point of the grid;

[0044] Figure 4 an equivalent circuit diagram after the system is divided into a source and a load two subsystems;

[0045] Figure 5To construct a dual-machine grid-connected system topology;

[0046] Figure 6 For P ref_gfl Nyquist plots of the system under different grid voltage loop scaling factors when the voltage is increased to 0.7 pu and 0.8 pu respectively;

[0047] Figure 7 This is a diagram illustrating the collaborative control strategy of introducing a hysteresis comparator to control the output of grid-connected renewable energy and the proportional coefficient of the grid-connected energy storage voltage loop in some embodiments of this application.

[0048] Figure 8 Nyquist plots of the system with different grid current loop scaling factors when Pref_gfl is increased to 0.8 pu, 0.9 pu and 1.0 pu respectively;

[0049] Figure 9 For some embodiments of this application, a piecewise line graph of the proportional coefficient of grid-connected renewable energy output to grid-connected current loop under stability margin constraints is shown.

[0050] Figure 10 Simulated waveforms of grid-connected power output under different grid-connected power conditions, with and without the parameter adaptive control strategy of this application.

[0051] Figure 11 The simulation diagram shows the grid-connected power output of the grid under the parameter adaptive control strategy of this application;

[0052] Figure 12 This is a flowchart illustrating the adaptive adjustment method for control parameters of a network interconnection system in some embodiments of this application.

[0053] Figure 13 This is a schematic diagram of the structure of the adaptive adjustment device for control parameters of the network interconnection system in some embodiments of this application;

[0054] Figure 14 This is a diagram of the internal structure of a computer device in some embodiments of this application. Detailed Implementation

[0055] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0056] The working principle and scheme involved in this application are explained below.

[0057] Firstly, the application can establish single-machine small-signal impedance models of grid-following converters and grid-forming converters, and verify the accuracy of the single-machine small-signal impedance models through time-domain frequency sweeping. Specifically, the small-signal impedance modeling of the grid-following converters and the grid-forming converters both includes passive circuit part modeling and control system part modeling. The control loop of the grid-following converter includes a phase-locked loop control loop, a power outer loop control loop and a current inner loop control loop; the control loop of the grid-forming converter includes an active power synchronization control loop, a reactive power control loop and a voltage and current double closed-loop control loop.

[0058] When the system is in a steady state, both the two synchronization control modes can track the grid phase without static error. However, when the grid voltage is disturbed, the dynamic tracking ability of the synchronization control loop is prioritized, and real-time accurate tracking of the grid phase cannot be achieved. The grid coordinate system d s q s and the control system coordinate system d c q c are defined. The position of the grid coordinate system d s q s is determined by the grid voltage, and the position of the grid voltage space synthesis vector is the d-axis position in the grid coordinate system. Similarly, the position of the control system coordinate system d c q c is defined by the output phase angle of the synchronization control loop. In a steady state, the control system coordinate system d c q c and the grid coordinate system d s q s coincide. When the grid voltage is disturbed, there is a phase angle disturbance between the control system coordinate system and the system coordinate system of the grid point, as shown in Figure 1 Therefore, the physical quantity conversion matrix and the voltage small disturbance relationship in the two coordinate systems can be shown as follows:

[0059]

[0060] In the formula, is the electrical quantity in the grid coordinate system d s q s , is the coordinate conversion matrix, is the electrical quantity in the control system coordinate system d c q c , is the phase angle between the grid coordinate system d s q s and the control system coordinate system d c q c .

[0061] After performing small-signal modeling of the control system and passive circuit sections and unifying the coordinate system, the analytical expression for the converter's output impedance / admittance can be obtained.

[0062] To verify the correctness of the impedance / admittance modeling results, this application can sequentially inject voltage perturbations of 1~1000Hz in the dq coordinate system at the grid connection point of the time-domain simulation model. Since the admittance matrix in the dq coordinate system has four unknown variable elements, each frequency sweep requires the injection of two sets of linearly independent dq voltage perturbations. For example... Figure 2 and Figure 3 As shown, Figure 2 This is a scan measurement result of the output admittance of the grid-connected converter when a small disturbance voltage of 1~1000Hz is applied at the grid connection point. Figure 3 The output impedance scanning measurement results of the grid-type converter when a small disturbance voltage with a frequency of 1~1000Hz is applied at the grid connection point are presented.

[0063] It can be understood that the output admittance / output impedance of the converter in the dq coordinate system is a second-order square matrix containing four elements: dd component, dq component, qd component and qq component. Figure 2 (a) shows the amplitude-frequency curve and phase-frequency curve corresponding to the dd admittance component of the grid converter. Figure 2 (b) shows the amplitude-frequency and phase-frequency curves corresponding to the dq admittance components of the grid-type converter. Figure 2 (c) shows the amplitude-frequency and phase-frequency curves corresponding to the qd admittance component of the grid-type converter. Figure 3 In the middle (d), the amplitude frequency curve and phase frequency curve are the corresponding qq admittance components of the grid converter.

[0064] Similarly, Figure 3 (a) shows the amplitude-frequency curve and phase-frequency curve corresponding to the dd impedance component of the grid-type converter. Figure 3 (b) shows the amplitude-frequency and phase-frequency curves corresponding to the dq impedance components of the grid-type converter. Figure 3 (c) shows the amplitude-frequency and phase-frequency curves corresponding to the qd impedance components of the grid-type converter. Figure 2 In the middle (d), the amplitude frequency curve and phase frequency curve corresponding to the qq impedance component of the grid-type converter are shown.

[0065] Figure 3 and Figure 4 The frequency sweep results shown have a high degree of agreement with the theoretical results, verifying the correctness of the modeling part.

[0066] After modeling, the application can divide the system into two parts based on impedance analysis method, and apply generalized Nyquist stability criterion to analyze the influence of new energy output change of grid-connected type on small signal stability of the system. Specifically, the core of the stability criterion based on impedance method is to divide the system under study into two sub-systems of source and load, and then apply Nyquist criterion to analyze the stability of the whole system by impedance ratio of the two systems. The two sub-systems of source and load are generally equivalent to Thevenin equivalent circuit or Norton equivalent circuit. For a power network, the system can be divided into two sub-systems of source and load at any position in the grid, and the equivalent circuit of the two sub-systems can be as shown in Figure 5 . The impedance on the current source side is , the impedance on the voltage source side is , and according to the circuit equation, the current expression of the equivalent circuit can be:

[0067]

[0068] In the formula, is the current expression of the equivalent circuit, is the Norton equivalent current, is the Thevenin equivalent voltage, is a 2x2 order unit matrix.

[0069] In order to simplify the analysis, the topology result selected by the application is the topology structure of the grid-connected dual-machine grid-connected system. As shown in Figure 6 , PCC is the grid-connected point, Z g is the Thevenin equivalent impedance of the grid side in series with the infinite power source, Z load is the load impedance, L line is the line inductance between the grid-connected point and the load, L f1 is the inductance of the grid-connected type converter, U gfl is the output voltage of the grid-connected type converter, P gfl is the output active power of the grid-connected type converter, I gfl is the output current of the grid-connected type converter, Q gfl is the output reactive power of the grid-connected type converter, L1 is the line inductance between the grid-connected type converter and the grid-connected point, P gflo is the active power provided by the grid-connected type converter at the grid-connected point, Q gflo is the reactive power provided by the grid-connected type converter at the grid-connected point, L f2 is the inductance of the grid-constructing type converter, U gfm is the output voltage of the grid-constructing type converter, P gfm is the output active power of the grid-constructing type converter, I gfm is the output current of the grid-constructing type converter, Q gfm is the output reactive power of the grid-constructing type converter, L2 is the line inductance between the grid-constructing type converter and the grid-connected point, Pgfmo Q represents the active power provided by the grid-connected converter at the grid connection point. gfmo The reactive power provided by the grid-connected converter at the grid connection point.

[0070] Since the equivalent impedance of a phase-locked loop (PLL) controlled converter does not have a right-half-plane zero, and the equivalent impedance of a power synchronization loop (PSL) controlled converter does not have a right-half-plane pole, the equivalent impedance of a PLL-controlled converter may have a right-half-plane pole, and the equivalent impedance of a power synchronization loop (PSL) controlled converter may have a right-half-plane zero. The grid impedance has neither a right-half-plane zero (negative resistance) nor a right-half-plane pole. Therefore, taking the output impedance of the GFM converter (i.e., the grid-connected converter) and the line impedance to the grid connection point as Z1(s) (no right-half-plane pole), and combining the output impedance of the GFL converter (i.e., the grid-connected converter) and the line impedance to the grid connection point with the total grid impedance as Z2(s), we have:

[0071]

[0072] In the formula, Z gfm (s) represents the output impedance of the grid-type converter, Z l2 (s) represents the impedance of the line from the grid-connected converter to the grid connection point, Z gfl (s) represents the output impedance of the grid-connected converter, Z l1 (s) represents the impedance of the line from the grid-connected converter to the grid connection point.

[0073] Based on this, the generalized Nyquist stability criterion can be applied to Z1(s) / Z2(s).

[0074] This application can maintain a system amplitude threshold of 14dB as the final control target, and dynamically adjust the voltage loop proportional coefficient of the grid-connected converter and the current loop proportional coefficient of the grid-connected converter in segments according to the changes in the output of new energy sources.

[0075] Specifically, by plotting the Nyquist curve for Z1(s) / Z2(s), it was found that when the output per unit value P of the grid converter... ref_gfl When the voltage loop proportional coefficient K of the grid converter is 0.1 pu and the amplitude margin h is approximately 14 dB, the voltage loop proportional coefficient K is... pv_gfm It is 5.5 pu; P ref_gfl When K is gradually increased to 0.3 pu and 0.5 pu, pv_gfm Maintaining 5.5 pu, the amplitude margin h can still be kept at around 14 dB. However, if Figure 6 As shown in (a), when P ref_gfl When upgrading to 0.7 PU, K needs to be adjusted. pv_gfm To keep the amplitude margin h around 14dB, it needs to be increased to 50p.u.

[0076] like Figure 7 As shown in (b), when P ref_gfl When upgraded to 0.8 PU, even if K... pv_gfm Increasing it to 100 p.u. does not maintain the amplitude margin at around 14 dB, therefore, other parameters need to be adjusted accordingly. Additionally, K... pv_gfm An excessively large value for K may amplify small disturbances in the system voltage, resulting in excessively high voltage sensitivity, which is detrimental to system voltage stability and may cause the converter to fail to maintain a stable grid connection. Therefore, the configurable K value is... pv_gfm The upper limit is 50 p.u., and other parameters are adjusted in conjunction with it.

[0077] Based on this, under this operating condition, the following collaborative control strategy for the proportional coefficient of the voltage loop of grid-connected renewable energy and grid-connected energy storage can be adopted: when the output P of grid-connected renewable energy is P ref_gfl When the voltage is less than 0.6 pu, set the grid voltage loop scaling factor K. pv_gfm It is 5.5 PU; when combined with the grid's new energy output P ref_gfl When the voltage is between 0.6 pu and 0.7 pu, set the grid voltage loop scaling factor K. pv_gfm It is 50 pu; when connected with the grid, the new energy output P ref_gfl When the voltage is greater than 0.7 pu, maintain the grid voltage loop scaling factor K. pv_gfm With 50 pu remaining constant, consider coordinating the control of other parameters.

[0078] To enhance the anti-interference capability and stability of the coordinated control, this application introduces a hysteresis comparator into the control strategy. This avoids the problem of repeated oscillations in the proportional coefficient of the grid-connected voltage loop when the output of the grid-connected renewable energy source fluctuates near a threshold, thus improving the anti-interference capability and operational stability of the coordinated control loop. The coordinated control strategy incorporating the grid-connected renewable energy output and the proportional coefficient of the grid-connected energy storage voltage loop using the hysteresis comparator can be described as follows: Figure 8 As shown.

[0079] Furthermore, in P ref_gfl =0.8pu, K pv_gfm When the current loop ratio K of the grid converter is 50p.u., try reducing it. pv_gfl The Nyquist curve can be drawn as follows: Figure 8 As shown in (a), under this operating condition, adjusting the current loop parameters to 0.85 times the original value (1.915) is sufficient to achieve a stability margin of over 14 dB. In P... ref_gfl =0.9pu, K pv_gfm When the current loop proportional coefficient K of the grid-connected converter is set to 50p.u., respectively. pc_gflThe Nyquist curves of the system, plotted as 0.9, 0.85, 0.80, 0.75, and 0.70 times the initial coefficients, are as follows: Figure 8 As shown in (b), it can be seen that when the current loop proportional coefficient K of the grid-type converter is... pc_gfl When the value is 0.75 times the original value (1.690), the Nyquist curve of the system intersects the negative real axis at approximately (-0.19, 0), and the stability margin meets the requirements.

[0080] When P ref_gfl =1.0 pu, K pv_gfm When the current loop proportional coefficient K of the grid converter is 50 pu, set it separately according to the grid converter current loop proportional coefficient K. pc_gfl The Nyquist curves of the system, plotted as 0.9, 0.85, 0.80, 0.75, and 0.70 times the initial coefficients, are as follows: Figure 9 As shown in (c). As can be seen from the figure, when the current loop proportionality coefficient K of the grid-type converter... pc_gfl When the value is 0.65 times the original value (1.464), the Nyquist curve of the system intersects the negative real axis at approximately (-0.163, 0), and the stability margin meets the requirements.

[0081] By performing a linear fit on the above three sets of data points, we can obtain the following fitting function:

[0082]

[0083] set up:

[0084]

[0085] Figure 10 A piecewise line graph of the proportional coefficient of grid-connected renewable energy output to grid-connected current loop under stability margin constraints.

[0086] To verify the effectiveness of the above control strategy, this application can be simulated in simulation software. The initial setting for grid-connected renewable energy active power output is 0.3 pu, which is increased to 0.5 pu at t=10s and to 0.7 pu at t=15s, without changing the original control parameters. The simulated grid-connected power waveform is as follows: Figure 10 As shown in (a), the system exhibits oscillation and instability. Using the proposed collaborative control strategy, the proportional gain of the grid-connected energy storage voltage loop is increased to 50 p.u. at t=15s. The simulated grid-connected power waveform is shown below. Figure 10 As shown in (b), the grid-connected and grid-connected power exhibits decaying oscillations after t=15s, while the system remains stable. At t=20s, the output of the grid-connected renewable energy is further increased to 0.9 pu. The grid-connected voltage loop proportional coefficient remains unchanged at 50 p.u., and all other parameters remain unchanged. Figure 10The middle (c) is the follow-up network current loop parameter unchanged when the follow-up network grid-connected power simulation waveform diagram, it can be seen that the system oscillation instability. Using the proposed collaborative control strategy, the follow-up network current loop proportional coefficient is adaptively changed, such as Figure 11 As shown in the middle (d), it can be seen that the grid-connected power decays and oscillates to a steady state, and the system remains stable. Continue to increase the follow-up network type new energy output to 1.0 p.u., and the system still remains stable using the proposed collaborative control strategy. Figure 12 For the collaborative control strategy, the follow-up network type new energy output is continuously increased to 1.0 p.u. The follow-up network grid-connected power simulation waveform is shown. It can be seen that under the proposed collaborative control strategy, as the follow-up network type new energy output increases, the system always remains stable. Thus, the effectiveness of the proposed collaborative control strategy is verified.

[0087] By comparing with the traditional non-adaptive parameter control, the effectiveness of the control strategy provided by the present application can be verified.

[0088] In combination with the above description, the control parameter adaptive adjustment method of the follow-up network grid-connected interconnection system provided by the present application is described below.

[0089] In some embodiments, the present application provides a control parameter adaptive adjustment method of a follow-up network grid-connected interconnection system. Wherein, the follow-up network grid-connected interconnection system can include a follow-up network type converter and a network type converter applied to a new energy station. As shown in the figure, Figure 7 The method provided by the present application can include the following steps:

[0090] S102: Obtain the output per unit value of the follow-up network type converter and the current voltage loop proportional coefficient of the network type converter;

[0091] S104: If the output per unit value is less than 0.7 per unit value, and the current voltage loop proportional coefficient is 5.5 per unit value, the voltage loop proportional coefficient of the network type converter is kept at 5.5 per unit value;

[0092] S106: If the output per unit value is greater than or equal to 0.7 per unit value, and the current voltage loop proportional coefficient is 5.5 per unit value, the voltage loop proportional coefficient of the network type converter is adjusted to 50 per unit value;

[0093] S108: If the output per unit value is less than 0.6 per unit value, and the current voltage loop proportional coefficient is 50 per unit value, the voltage loop proportional coefficient of the network type converter is adjusted to 5.5 per unit value;

[0094] S110: If the output per unit value is greater than or equal to 0.6 per unit value, and the current voltage loop proportional coefficient is 50 per unit value, the voltage loop proportional coefficient of the network type converter is kept at 50 per unit value.

[0095] This application can be based on the per-unit output value of the grid-connected converter in the grid interconnection system (i.e., P in the above embodiment). ref_gfl The application uses the current voltage loop proportional coefficient of the grid-type converter to control the voltage loop proportional coefficient of the grid-type converter, thereby enhancing the small-disturbance stability of the system. Furthermore, to increase anti-interference capability and stability, a hysteresis comparator can be introduced during the control process to avoid the problem of repeated oscillations in the voltage loop proportional coefficient, thus improving the anti-interference capability and operational stability of the control loop.

[0096] Specifically, please combine Figure 13 If the current voltage loop proportional gain is 5.5 pu, then the per-unit output value of the grid converter can be compared with 0.7 pu. If the per-unit output value is greater than or equal to 0.7 pu, then the voltage loop proportional gain should be adjusted from 5.5 pu to 50 p.u. to maintain the system's amplitude margin at around 14 dB. Otherwise, the voltage loop proportional gain can be maintained at 5.5 pu.

[0097] If the current voltage loop proportional gain is 50 p.u., then the per-unit output value of the grid converter can be compared with 0.6 pu. If the per-unit output value is less than or equal to 0.6 pu, then the voltage loop proportional gain can be reduced from 50 p.u. to 5.5 pu. Otherwise, the voltage loop proportional gain can be kept at 50 p.u.

[0098] In this way, the voltage loop proportional coefficient of the grid-type converter can be dynamically set in segments, thereby improving the small-disturbance stability of the grid-connected new energy-grid-type energy storage interconnection system.

[0099] When P ref_gfl Too large, for example, P ref_gfl At a voltage ratio of 0.8 pu, while adjusting the voltage loop proportional gain of the grid converter can improve the small-disturbance stability of the system to some extent, it cannot maintain the system's amplitude margin at around 14 dB. Furthermore, an excessively large voltage loop proportional gain is detrimental to the system's voltage stability. Therefore, at P... ref_gfl If the value is too large, the voltage loop proportional coefficient and the current loop proportional coefficient can be adjusted in a coordinated manner to keep the system's amplitude margin at around 14dB, thereby further improving the system's small disturbance stability.

[0100] Therefore, in some embodiments, the method provided in this application further includes the following steps:

[0101] Step A1: If the output per-unit value is less than the first preset per-unit value, then set the current loop proportional coefficient of the grid-connected converter to 2.253; wherein the first preset per-unit value is greater than or equal to 0.7 per-unit value;

[0102] Step A3: if the output unit value is greater than or equal to the first preset unit value and less than or equal to 1 unit value, setting the current loop proportional coefficient of the grid-following type converter according to a target function expression obtained by pre-fitting; wherein the target function expression is a function expression taking the current loop proportional coefficient of the grid-following type converter as the dependent variable and taking the output unit value of the grid-following type converter as the independent variable.

[0103] Specifically, in the case that the output unit value of the grid-following type converter is less than the first preset unit value, the application can set the current loop proportional coefficient of the grid-following type converter to a fixed value of 2.253. When the output unit value of the grid-following type converter is greater than or equal to the first preset unit value, the application can adjust the current loop proportional coefficient according to the target function expression obtained by pre-fitting, so as to cooperatively adjust the voltage loop proportional coefficient and the current loop proportional coefficient, thereby further improving the small signal stability of the system.

[0104] It can be understood that the specific value of the first preset unit value can be determined according to actual conditions. In some examples, the first preset unit value is 0.72 unit value.

[0105] It can be understood that the target function expression can be obtained by data fitting according to simulation data and grid operation data. In some examples, the target function expression is:

[0106]

[0107] In the formula, is the output unit value of the grid-following type converter, is the current loop proportional coefficient of the grid-following type converter.

[0108] As can be seen from the above embodiments, the application can dynamically segmentally adjust the voltage loop proportional coefficient of the grid-forming type converter and the current loop proportional coefficient of the grid-following type converter according to the grid-following type new energy output change. Ultimately, the control effect of maintaining the small signal stability amplitude margin of the grid-following type new energy output in the range of 0~1 p.u. at above 14dB is achieved.

[0109] The control parameter adaptive adjustment device for the grid-forming interconnected system provided by the embodiments of the application is described below, and the control parameter adaptive adjustment device for the grid-forming interconnected system described below can be mutually corresponding and referred to with the control parameter adaptive adjustment method for the grid-forming interconnected system described above.

[0110] In some embodiments, the application provides a control parameter adaptive adjustment device 200 for a grid-forming interconnected system, wherein the grid-forming interconnected system comprises a grid-following type converter and a grid-forming type converter applied to a new energy station. As shown in Figure 14 The device 200 provided by the application can comprise:

[0111] The output acquisition module 201 is configured to acquire an output standard value of the grid-following converter and a current voltage loop proportional coefficient of the grid-forming converter.

[0112] The first coefficient adjustment module 202 is configured to, if the output standard value is less than 0.7 standard value and the current voltage loop proportional coefficient is 5.5 standard value, maintain the voltage loop proportional coefficient of the grid-forming converter as 5.5 standard value.

[0113] The second coefficient adjustment module 203 is configured to, if the output standard value is greater than or equal to 0.7 standard value and the current voltage loop proportional coefficient is 5.5 standard value, adjust the voltage loop proportional coefficient of the grid-forming converter to 50 standard value.

[0114] The third coefficient adjustment module 204 is configured to, if the output standard value is less than 0.6 standard value and the current voltage loop proportional coefficient is 50 standard value, adjust the voltage loop proportional coefficient of the grid-forming converter to 5.5 standard value.

[0115] The fourth coefficient adjustment module 205 is configured to, if the output standard value is greater than or equal to 0.6 standard value and the current voltage loop proportional coefficient is 50 standard value, maintain the voltage loop proportional coefficient of the grid-forming converter as 50 standard value.

[0116] In some embodiments, the device 200 further comprises:

[0117] The fifth coefficient adjustment module is configured to, if the output standard value is less than a first preset standard value, set the current loop proportional coefficient of the grid-following converter as 2.253; wherein the first preset standard value is greater than or equal to 0.7 standard value.

[0118] The sixth coefficient adjustment module is configured to, if the output standard value is greater than or equal to the first preset standard value and less than or equal to 1 standard value, set the current loop proportional coefficient of the grid-following converter according to a target function expression obtained by pre-fitting.

[0119] The target function expression is a function expression taking the current loop proportional coefficient of the grid-following converter as a dependent variable and taking the output standard value of the grid-following converter as an independent variable.

[0120] In some embodiments, the first preset standard value is 0.72 standard value.

[0121] In some embodiments, the target function expression is:

[0122]

[0123] In the formula, k is the current loop proportional coefficient of the grid-following converter, and P is the output standard value of the grid-following converter. a power reference value of the grid-connected inverter, a current loop proportional coefficient of the grid-connected inverter.

[0124] In one embodiment, the present application further provides a storage medium, which stores computer readable instructions, and the computer readable instructions, when executed by one or more processors, cause the one or more processors to perform the steps of the method for adaptive adjustment of control parameters of a grid-connected interconnection system according to any embodiment.

[0125] In one embodiment, the present application further provides a computer device, which stores computer readable instructions, and the computer readable instructions, when executed by one or more processors, cause the one or more processors to perform the steps of the method for adaptive adjustment of control parameters of a grid-connected interconnection system according to any embodiment.

[0126] Schematically, Figure 14 An internal structure schematic diagram of a computer device according to an embodiment of the present application is shown in the figure, which can be a server in one example. Referring to ​ The computer device 900 includes a processing component 902, which further includes one or more processors, and a memory resource represented by the memory 901, for storing instructions executable by the processing component 902, such as an application program. The application program stored in the memory 901 can include one or more than one module each corresponding to a set of instructions. In addition, the processing component 902 is configured to execute the instructions to perform the steps of the method for adaptive adjustment of control parameters of a grid-connected interconnection system according to any embodiment described above.

[0127] The computer device 900 can further include a power supply component 903 configured to perform power management of the computer device 900, a wired or wireless network interface 904 configured to connect the computer device 900 to a network, and an input / output (I / O) interface 905. The computer device 900 can operate based on an operating system stored in the memory 901, such as Windows Server TM, Mac OS X TM, Unix TM, Linux TM, Free BSD TM, or the like.

[0128] Those skilled in the art can understand that the internal structure of the computer device shown in the present application is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or less components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0129] Finally, it should be noted that the terms "first" and "second", and the like, herein do not denote any order, quantity, combination or importance, but are used to identify one element from another, and do not imply that the specific identities thereof are essential or that the identities are chronological or related in their occurrence. Also, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element. Also, "a", "an", "the", and "said" are used to refer to one or more than one (i.e., to "at least one") of the referenced elements, unless otherwise specified. A plurality also means two or more, such as 2, 3, 5, or 8, etc. "And / or" includes any and all combinations of one or more of the associated listed items.

[0130] The various embodiments described in this specification are presented by way of example, and are not intended to limit the scope of the application. Each embodiment is presented in a way that emphasizes the differences between the embodiments and the other embodiments, but the embodiments can be combined according to the needs of the user.

[0131] The above description of disclosed embodiments provides enabling disclosure sufficient for one of ordinary skill in the art to practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended 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 adaptive adjustment of control parameters of a networked system, characterized in that, The follow-grid interactive system comprises a follow-grid converter and a grid-forming converter applied to a new energy station, and the method comprises the following steps: an output per-unit value of the follow-grid converter and a current voltage loop proportional coefficient of the grid-forming converter are acquired; if the output per-unit value is less than 0.7 per-unit value and the current voltage loop proportional coefficient is 5.5 per-unit value, the voltage loop proportional coefficient of the grid-forming converter is kept as 5.5 per-unit value; if the output per-unit value is greater than or equal to 0.7 per-unit value and the current voltage loop proportional coefficient is 5.5 per-unit value, the voltage loop proportional coefficient of the grid-forming converter is adjusted to 50 per-unit value; if the output per-unit value is less than 0.6 per-unit value and the current voltage loop proportional coefficient is 50 per-unit value, the voltage loop proportional coefficient of the grid-forming converter is adjusted to 5.5 per-unit value; if the output per-unit value is greater than or equal to 0.6 per-unit value and the current voltage loop proportional coefficient is 50 per-unit value, the voltage loop proportional coefficient of the grid-forming converter is kept as 50 per-unit value.

2. The method of claim 1, wherein, The method further comprises the following steps: if the output per-unit value is less than a first preset per-unit value, a current loop proportional coefficient of the follow-grid converter is set as 2.253; wherein the first preset per-unit value is greater than or equal to 0.7 per-unit value; if the output per-unit value is greater than or equal to the first preset per-unit value and less than or equal to 1 per-unit value, the current loop proportional coefficient of the follow-grid converter is set according to a target function expression obtained by pre-fitting; wherein the target function expression is a function expression taking the current loop proportional coefficient of the follow-grid converter as a dependent variable and taking the output per-unit value of the follow-grid converter as an independent variable.

3. The method of claim 2, wherein, The first preset per-unit value is 0.72 per-unit value.

4. The method of claim 3, wherein, The target function expression is: In the formula, is the output unit of the grid-following converter, is the current loop proportional coefficient of the grid-following converter.

5. A device for adaptive adjustment of control parameters of a networked system, characterized in that The follow-grid interactive system comprises a follow-grid converter and a grid-forming converter applied to a new energy station, and the device comprises the following steps: an output per-unit value of the follow-grid converter and a current voltage loop proportional coefficient of the grid-forming converter are acquired; if the output per-unit value is less than 0.7 per-unit value and the current voltage loop proportional coefficient is 5.5 per-unit value, the voltage loop proportional coefficient of the grid-forming converter is kept as 5.5 per-unit value; if the output per-unit value is greater than or equal to 0.7 per-unit value and the current voltage loop proportional coefficient is 5.5 per-unit value, the voltage loop proportional coefficient of the grid-forming converter is adjusted to 50 per-unit value; if the output per-unit value is less than 0.6 per-unit value and the current voltage loop proportional coefficient is 50 per-unit value, the voltage loop proportional coefficient of the grid-forming converter is adjusted to 5.5 per-unit value; if the output per-unit value is greater than or equal to 0.6 per-unit value and the current voltage loop proportional coefficient is 50 per-unit value, the voltage loop proportional coefficient of the grid-forming converter is kept as 50 per-unit value.

6. The apparatus of claim 5, wherein, The device further comprises the following steps: The fifth coefficient adjustment module is configured to set the current loop proportional coefficient of the grid-following type converter to 2.253 if the output per unit value is less than a first preset per unit value, wherein the first preset per unit value is greater than or equal to 0.7 per unit value. The sixth coefficient adjustment module is configured to set the current loop proportional coefficient of the grid-following type converter according to a target function expression obtained by pre-fitting if the output per unit value is greater than or equal to the first preset per unit value and less than or equal to 1 per unit value. The target function expression is a function expression with the current loop proportional coefficient of the grid-following type converter as a dependent variable and the output per unit value of the grid-following type converter as an independent variable.

7. The apparatus of claim 6, wherein, The first preset per unit value is 0.72 per unit value.

8. The apparatus of claim 7, wherein, The target function expression is: In the formula, is the output unit of the grid-following converter, is the current loop proportional coefficient of the grid-following converter.

9. A storage medium, characterized by The storage medium stores computer readable instructions, and the computer readable instructions are executed by one or more processors to perform the steps of the control parameter adaptive adjustment method of the grid-connected system according to any one of claims 1 to 4.

10. A computer device, comprising: Comprise: One or more processors and a memory; The memory stores computer readable instructions, and the computer readable instructions are executed by the one or more processors to perform the steps of the control parameter adaptive adjustment method of the grid-connected system according to any one of claims 1 to 4.

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