Inverter droop control method and system, electronic device and readable storage medium

Abstract

The application provides an inverter droop control method and system, electronic equipment and a readable storage medium. The method comprises: generating an initial curve family of reactive power and voltage on the inverter side based on an established single-machine infinite bus (SMIB) model; screening the generated initial curve family according to a preset power system static stability criterion to obtain a stable region atlas capable of meeting the stable operation of the SMIB model; setting various different droop control curves in the stable region atlas; and determining a droop coefficient range based on the intersection between the droop control curves and the stable region atlas, and performing reactive power-voltage droop control based on the droop coefficient range. The application can accurately identify the stable domain of the reactive power-voltage droop coefficient of the network type inverter in advance and offline by constructing the SMIB model and coupling the inherent mathematical relationship and strict stability criterion.

Description

Technical Field

[0001] This application relates to the field of computer technology, specifically to an inverter droop control method, system, electronic device, and readable storage medium. Background Technology

[0002] Against the backdrop of building a new power system with new energy sources as the mainstay, grid-connected energy storage inverters have become core equipment supporting the stable operation of the power grid because they can autonomously establish and maintain grid voltage and frequency.

[0003] Grid-connected inverters differ from traditional grid-connected inverters in that they do not rely on stable voltage and frequency signals provided by an external power grid, but actively establish and maintain grid voltage and frequency. Reactive power-voltage droop control is a key technology in this type of inverter. An important function of grid-connected inverters is to achieve a smooth and seamless switch between grid-connected and islanded modes. Employing QV droop control ensures that when a grid fault occurs and the system switches from grid-connected to islanded mode, the inverter can quickly take over control of voltage and frequency, achieving continuity and a smooth transition of control variables, thus preventing system collapse.

[0004] The performance of reactive power voltage droop control directly depends on the proper selection of the droop coefficient: too low a coefficient will result in insufficient reactive power regulation capability and affect the voltage control effect; too high a coefficient may exacerbate voltage deviation and even cause system instability.

[0005] Currently, the determination of the droop factor in engineering projects mostly relies on rough empirical formulas based on the maximum reactive power capacity and the allowable voltage deviation, and is optimized through trial and error using simulation methods. Summary of the Invention

[0006] This application provides an inverter droop control method, system, electronic device, and readable storage medium to address the technical problem that current methods for determining the droop coefficient lack theoretical support, cannot reflect the inherent stability constraints of the system, and are difficult to guarantee the stability of the system under all operating conditions, especially the inability to systematically determine the stable operating boundary of the droop coefficient.

[0007] In a first aspect, this application provides an inverter droop control method, including:

[0008] Based on the established Single-Machine Infinite Block (SMIB) system model, an initial family of curves for reactive power and voltage on the inverter side is generated.

[0009] Based on the preset power system static stability criteria, the generated initial curve family is screened to obtain a stable region map that can satisfy the stable operation of the SMIB model.

[0010] Various droop control curves are set in the stable region map;

[0011] Based on the intersection between the droop control curve and the stable region map, the range of the droop coefficient is determined; and

[0012] Based on the aforementioned droop coefficient range, reactive power-voltage droop control is performed.

[0013] In one example, the setting of various droop control curves in the stable region map includes:

[0014] According to the control objective of the inverter, a reference point for reactive power-voltage droop control is set in the coordinate system of the stable region map;

[0015] Using the aforementioned reference point as the axis, the value of the sag coefficient is adjusted to obtain different sag control curves.

[0016] In one example, determining the droop coefficient range based on the intersection between the droop control curve and the stable region map includes:

[0017] Determine whether there is a valid intersection between the various droop control curves and the stable region map;

[0018] The effective intersection means that all intersection points of the droop control curve and the stable region map are within the allowable range of the inverter grid connection point voltage.

[0019] In one example, determining the droop coefficient range based on the intersection between the droop control curve and the stable region map includes:

[0020] Determine that at least one of the droop control curves has a valid intersection with the stable region map.

[0021] The minimum value of at least one droop coefficient corresponding to at least one droop control curve that has a valid intersection with the stable region map is determined as the boundary value of the droop coefficient range.

[0022] In one example, the step of filtering the generated initial curve family according to a preset power system static stability criterion to obtain a stable region map that can satisfy the stable operation of the SMIB model includes:

[0023] Based on the preset static stability criteria of the power system, initial curves that do not meet the static stability requirements of the power system are eliminated.

[0024] In one example, the preset power system static stability criterion includes: the power system's power angle stability and reactive voltage stability are simultaneously satisfied.

[0025] Satisfying the work angle stability:

[0026]

[0027] Satisfy reactive voltage stability:

[0028]

[0029] in, Active power Reactive power The phase angle, This represents the inverter grid connection point voltage in the SMIB model.

[0030] In one example, the active and reactive power on the inverter side satisfy the following:

[0031] (5)

[0032] (6)

[0033] in, Active power Reactive power The phase angle, To represent the inverter grid connection point voltage in the SMIB model, To represent the grid-side voltage in the SMIB model, These are the equivalent impedance parameters of the line. For composite impedance,

[0034] The initial family of curves for reactive power and voltage on the inverter side, generated based on the established Single-Machine Infinite Block (SMIB) system model, includes:

[0035] Define the grid-side voltage in the SMIB model. The value and the inverter grid connection point voltage The allowable operating range is determined by traversing different active power setpoints through equations (5) and (6). P and Calculate and generate a series of reactive power characteristics of the system under different active power injections. Q With voltage V The changing natural characteristic curves constitute the initial family of curves.

[0036] In one example, the initial family of curves for reactive power versus voltage on the inverter side, based on an established Single-Machine Infinite Block (SMIB) system model, includes:

[0037] Based on the SMIB model, the parameters of the line equivalent impedance are calculated. , ,

[0038] in, , ,

[0039] in, This represents the resistance value. This represents the value of the reactance. This represents the numerical value of the composite impedance.

[0040] In one example, the value of the resistor The value of the reactance and the numerical value of the composite impedance. satisfy:

[0041]

[0042]

[0043]

[0044]

[0045] Where SCR is the short-circuit ratio of the power system and XRR is the reactance-resistance ratio of the power system.

[0046] Secondly, embodiments of this application provide an inverter droop control system, including:

[0047] The initial curve family generation module is used to generate an initial curve family of reactive power and voltage on the inverter side based on the established Single-Machine Infinite System (SMIB) model.

[0048] The stable region map acquisition module is used to filter the generated initial curve family according to the preset power system static stability criterion to obtain a stable region map that can meet the stable operation of the SMIB model.

[0049] A droop control curve setting module is used to set various droop control curves in the stable region map.

[0050] The droop coefficient range determination module is used to determine the droop coefficient range based on the intersection between the droop control curve and the stable region map; and

[0051] The droop control module is used to perform reactive power-voltage droop control based on the droop coefficient range.

[0052] Thirdly, embodiments of this application also provide an electronic device, including a memory and a processor; the memory stores an application program, and the processor is used to run the application program in the memory to perform the steps in the inverter droop control method of the first aspect described above.

[0053] Fourthly, embodiments of this application also provide a computer-readable storage medium storing instructions adapted for loading by a processor to execute the steps in the inverter droop control method of the first aspect described above.

[0054] From the above, it can be concluded that this application has the following beneficial effects:

[0055] By constructing the SMIB model and coupling its inherent mathematical relationships with rigorous stability criteria, the pain point of traditional empirical methods and trial-and-error simulations in determining the droop coefficient is solved. It can accurately identify the stability domain of the reactive power-voltage droop coefficient of grid-connected inverters in advance and offline, fundamentally ensuring the planning, design and safe and stable operation of the power grid. Attached Figure Description

[0056] Figure 1 This is a flowchart illustrating the inverter droop control method provided in an embodiment of this application.

[0057] Figure 2 This is a flowchart illustrating the method for determining the range of the reactive power-voltage droop coefficient of an inverter, as provided in an embodiment of this application.

[0058] Figure 3 This is a schematic diagram of the SMIB model structure provided in the embodiments of this application.

[0059] Figure 4 These are QV line graphs for different P values ​​provided in the embodiments of this application.

[0060] Figure 5 This is a schematic diagram illustrating the determination of the slope of a drooping curve provided in an embodiment of this application.

[0061] Figure 6 This is a schematic diagram of the inverter droop control system provided in an embodiment of this application.

[0062] Figure 7 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application.

[0063] Figure 8 This is a schematic diagram of the structure of the storage medium provided in the embodiments of this application. Detailed Implementation

[0064] Currently, the determination of the droop factor in engineering projects largely relies on rough empirical formulas based on maximum reactive power capacity and allowable voltage deviation, and is optimized through trial and error using simulation. This method lacks theoretical support, fails to reflect the inherent stability constraints of the system, and is difficult to guarantee the system's stability under all operating conditions. In particular, it cannot systematically determine the stable operating boundary of the droop factor, thus restricting the optimization of grid-connected inverter control performance and the improvement of system safety.

[0065] To address the aforementioned issues, embodiments of this application provide an inverter droop control method, system, device, and readable storage medium, which will be described in detail below.

[0066] like Figure 1 As shown, Figure 1 This is a schematic diagram of the inverter droop control method provided in an embodiment of this application.

[0067] like Figure 1 As shown, the inverter droop control method in this embodiment includes the following:

[0068] Step S110: Based on the established Single-Machine Infinite Block System (SMIB) model, generate an initial family of curves for reactive power and voltage on the inverter side.

[0069] Step S120: Based on the preset power system static stability criteria, the generated initial curve family is screened to obtain a stable region map that can satisfy the stable operation of the SMIB model.

[0070] Step S130: Set various droop control curves in the stable region map.

[0071] Step S140: Determine the range of droop coefficients based on the intersection between the droop control curve and the stable region map.

[0072] Step S150: Perform reactive power-voltage droop control based on the droop coefficient range.

[0073] In one example, the inverter is a grid-connected energy storage inverter.

[0074] In step S110, in one example, the value of the resistor is... The value of the reactance and the numerical value of the composite impedance. satisfy:

[0075] (1)

[0076] (2)

[0077] (3)

[0078] (4)

[0079] Where SCR is the short-circuit ratio of the power system and XRR is the reactance-resistance ratio of the power system.

[0080] In one example, based on the established Single-Machine Infinite Block (SMIB) system model, an initial family of curves for reactive power and voltage on the inverter side is generated, including:

[0081] The active and reactive power on the inverter side meet the following requirements:

[0082] (5)

[0083] (6)

[0084] in, Active power Reactive power The phase angle, To represent the inverter grid connection point voltage in the SMIB model, To represent the grid-side voltage in the SMIB model, These are the equivalent impedance parameters of the line. It is a composite impedance.

[0085] Based on the SMIB model (see above) Figure 3 ), Parameters for calculating the equivalent impedance of a line , ,

[0086] in, , (7)

[0087] , (8)

[0088] in, This represents the resistance value. This represents the value of the reactance. This represents the numerical value of the composite impedance.

[0089] The parameters of the above-mentioned line equivalent impedance , and the value of the resistance. The value of reactance and the numerical value of composite impedance. All of these were calculated based on the SMIB model.

[0090] To facilitate understanding, the SMIB model will be introduced below.

[0091] Figure 3 This is a schematic diagram of the SMIB model structure provided in an embodiment of this application. See also... Figure 3 The SMIB model mainly consists of a two-node power system model, divided into nodes A and B. Node A is the PQ node, representing the inverter itself, and node B is the slack node, representing the power grid. The voltage and phase angle at node A are... and The voltage and phase angle at node B are And 0°. The model between nodes AB is a complex impedance model, consisting of resistors. and reactance Composition. The parameters of the complex impedance model are determined by the SCR (Short-Circuit Ratio) and XRR (Reactance to Resistance Ratio) of the power system, and SCR and XRR are known parameters.

[0092] In one example, the initial family of curves for reactive power and voltage on the inverter side, generated based on the established Single-Unit Infinite Bus (SMIB) model, includes:

[0093] Define the grid-side voltage in the SMIB model. The value and the inverter grid connection point voltage The allowable operating range is determined by traversing different active power setpoints through equations (5) and (6). P and Calculate and generate a series of reactive power characteristics of the system under different active power injections. Q With voltage V The changing natural characteristic curves constitute the initial family of curves.

[0094] Referring to formulas (5) and (6) above, to complete the iteration of different active power setpoints... P and To calculate and generate the initial family of curves, it is necessary to calculate the parameters of the equivalent impedance of the line. , .

[0095] In one example, as shown in formulas (1), (2), (3), and (4) above, based on SCR and XXR with resistance and reactance Calculate the resistance based on the relationship. Reactance and composite impedance Z th Based on the calculated resistance Reactance and composite impedance Zth The parameters of the equivalent impedance of the line can be calculated using the above formulas (7) and (8). , Based on the calculated parameters of the line equivalent impedance , Using the above formulas (5) and (6), it is possible to iterate through different active power setpoints. P and The task is to calculate and generate the initial family of curves.

[0096] In one example, the QV curves of the initial family of curves are only approximately linear. The QV curves are derived by setting the grid-side voltage in the SMIB model. The value of the inverter grid connection point voltage The allowed operating range is then determined by iterating through the P values, which are generally between -1 and 1, thus deriving the family of QV curves. Here are four variables... P, Q, and V are two or three of which are determined, while the third variable is fixed; we set it first. V and V th Then set P traversal Find Q This yields the family of QV curves.

[0097] In step S120, in one example, the step of filtering the generated initial curve family according to a preset power system static stability criterion to obtain a stable region map that can satisfy the stable operation of the SMIB model includes:

[0098] Based on the preset static stability criteria of the power system, initial curves that do not meet the static stability requirements of the power system are eliminated.

[0099] In one example, the preset power system static stability criterion includes: the power system's power angle stability and reactive voltage stability are simultaneously satisfied.

[0100] Satisfying the work angle stability:

[0101]

[0102] Satisfy reactive voltage stability:

[0103]

[0104] in, Active power Reactive power The phase angle, This represents the inverter grid connection point voltage in the SMIB model.

[0105] Referring to formulas (5) and (6) above, take the derivative of formulas (5) and (6).

[0106] The stability of the work angle can be expressed as:

[0107]

[0108] Satisfying reactive voltage stability can be expressed as:

[0109]

[0110] Among them, the above expression for satisfying reactive voltage stability is derived by differentiating formula (2), and is obtained by substituting and simplifying formulas (4), (5), (6), (7) and (8).

[0111] The expression for reactive voltage stability is written this way simply for ease of calculation, because it requires iterating through the values ​​of P. The expression for reactive voltage stability can also be written directly as the partial derivative of Q with respect to V.

[0112] The SMIB model needs to simultaneously satisfy power angle stability and reactive voltage stability, which will be affected under different SCR conditions. and The value here This is the phase angle value, which is a variable and can take any value between 0 and 2π. Extremely high values ​​can cause these two stability conditions to be unsatisfactory. As SCR decreases, the point where the QV curve satisfies the conditions will deviate.

[0113] Figure 4 These are QV line graphs for different P values ​​provided in the embodiments of this application. Figure 4 This is the stable region map after screening. Here, under the condition of SCR=2, all cases where P is in the range of -1 to 1 satisfy the stability condition.

[0114] See Figure 4 , Figure 4 Only 5 P values ​​were set. Figure 4 Only a portion of the setpoints for P, ranging from -1pu to 1pu, under typical parameter conditions were traversed, and the spectrum of its stable region is shown below. Figure 4 The strip-shaped range shown. Figure 4Setting only 5 P values ​​(due to insufficient computer configuration, the graph will run very slowly) actually requires iterating through all P values ​​from -1 to 1 to obtain the QV curve family, or iterating through all P values ​​from -1 to 1 to obtain the QV curve family will make the droop coefficient calculation result more accurate.

[0115] Apart from Figure 4 The values ​​shown are -0.1, -0.5, 0.0, 0.5, and 1.0. The value of P can be other values. Since the power of the inverter is a per-unit value, all P values ​​from -1 to 1 need to be taken. The final strip range formed by traversing each P value from -1 to 1 is the strip range shown in the figure. For example, if P = -0.75, its graph will eventually fall inside the strip area shown in the figure.

[0116] In step S130, the core of the reactive voltage droop control strategy is defined by a droop control curve, as shown in the following formula.

[0117] (9)

[0118] in Q is the reactive power reference value for droop control. The change V is the reference value for the droop control voltage. The change in quantity. is the droop coefficient, which is the slope of the droop control curve.

[0119] Figure 5 This is a schematic diagram illustrating the determination of the slope of a drooping curve provided in an embodiment of this application.

[0120] In one example, the setting of various droop control curves in the stable region map includes:

[0121] According to the control objective of the inverter, a reference point for reactive power-voltage droop control is set in the coordinate system of the stable region map;

[0122] Using the aforementioned reference point as the axis, the value of the sag coefficient is adjusted to obtain different sag control curves.

[0123] See Figure 5 In one example, the reference point is arbitrarily chosen. Generally, the position of the reference point in the coordinate system is set to V=1, Q=0, meaning that no reactive power is generated when the voltage is 1. Setting the position of the reference point in the coordinate system to V=1, Q=0.1 or V=0.9, Q=0.2, or other positions, is also possible, depending on the specific working requirements.

[0124] In one example, based on the inverter's control objectives, a reference point for reactive power-voltage droop control is set in the VQ coordinate system, and... Figure 4 The resulting stable region map is clearly marked. The droop coefficient is adjusted using the reference point as the axis. By taking different values ​​of , different droop control curves can be plotted.

[0125] In step S140, in one example, determining the droop coefficient range based on the intersection between the droop control curve and the stable region map includes:

[0126] Determine whether there is a valid intersection between the various droop control curves and the stable region map;

[0127] The effective intersection means that all intersection points of the droop control curve and the stable region map are within the allowable range of the inverter's grid connection point voltage.

[0128] In one example, determining the droop coefficient range based on the intersection between the droop control curve and the stable region map includes:

[0129] Determine that at least one of the droop control curves has a valid intersection with the stable region map.

[0130] The minimum value of the droop coefficient corresponding to at least one droop control curve that has a valid intersection with the stable region map is determined as the boundary value of the droop coefficient range.

[0131] Figure 5 The black line intersects with all QV curves, and the intersections all meet the allowable voltage range of 0.9-1.1. The slope of the black line serves as the minimum droop coefficient. The black line is a droop control curve with a reference point set at (1, 0). Under typical parameters, the droop coefficient... The value of is 2.36, and the limit of the intersection with the stable region is... =0.9pu. The range of the droop coefficient is generally given by national or industry standards as a very large range. Currently, the national standard gives 0-10. This application can calculate the boundary of the droop coefficient under specific conditions and constraints. Here, the lower bound is calculated to be 2.36.

[0132] Pick Figure 5The slope of the black line is used as the minimum value of the droop coefficient (one of the boundary values, i.e., the minimum value) because the slope of the droop curve is the smallest when the reference point is set to (1, 0). Since the intersection of the droop curve (black line) and the QV curve is the final operating point (considering only droop control), the intersection of the black line and the line in the QV strip where P=-1 is already at the allowable voltage limit of 0.9. If it were lower, the voltage value at the intersection of the droop curve (black line) and the QV curve would exceed the allowable range of 0.9-1.1 when P=-1.

[0133] In summary, the minimum slope value of the droop curve that intersects with the QV curves corresponding to all P values ​​is taken as the boundary value (lower bound value) of the droop coefficient range.

[0134] In step S150, reactive power-voltage droop control is performed based on the droop coefficient range.

[0135] Because the method described above in this application (the method for determining the range of the inverter reactive power-voltage droop control coefficient) systematically determines the stable operating boundary of the droop coefficient, this method has theoretical support and can reflect the inherent stability constraints of the system. Applying the stable operating boundary of the droop coefficient systematically determined in this application to droop control ensures the stability of the system under all operating conditions, thereby contributing to the optimization of the control performance of grid-connected inverters and the improvement of system safety.

[0136] The inverter droop control method of this application enables the inverter to quickly take over the control of voltage and frequency when the grid fails or the system switches from grid-connected to islanded, thus achieving continuity and smooth transition of control variables and avoiding system collapse.

[0137] Figure 2 This is a schematic diagram illustrating a specific implementation of the method for determining the range of the reactive power-voltage droop coefficient of an inverter, as provided in the embodiments of this application.

[0138] See Figure 2 The method for determining the range of the reactive power-voltage droop coefficient of the inverter is achieved through the following steps:

[0139] 1. Establish the SMIB model and obtain the short-circuit ratio (SCR) and reactance-resistance ratio (XRR) of the power grid according to the required power grid operating conditions. Based on this model, calculate the parameters of the equivalent impedance of the line according to the predetermined system parameter relationships (1), (2), (3), and (4). , , In weak power grid conditions, the typical SCR value is 2, and the typical XRR value is 10.

[0140] 2. Based on this model, calculate the parameters of the equivalent impedance of the line according to the relationships (7) and (8). , .

[0141] 3. Set the grid-side voltage in the SMIB model The value of the inverter grid connection point voltage The allowed operating range. Based on the coefficients. and By using the power equations (5) and (6), and traversing different active power setpoints P, a series of natural characteristic curves characterizing the reactive power Q of the system under different active power injections as a function of voltage V are calculated and generated, forming an initial family of curves. The grid-side voltage in the SMIB model... The typical value is 1 pu, the inverter grid connection point voltage. The typical allowable operating range is 0.9~1.1 pu.

[0142] 4. Based on the preset static stability criteria of the power system, namely, the simultaneous satisfaction of power angle stability and reactive voltage stability, the initial curve family generated in step 3 is screened, and QV curves that do not meet the stability requirements are eliminated, thereby obtaining the feasible region for stable system operation. This region consists of the set of all QV curves that meet the stability conditions.

[0143] 5. In the VQ coordinate system, plot all the QV curves that meet the stability conditions selected in step 4. These curves together outline the stable operating boundary of the system under the stated operating conditions, forming a visualized stable region map.

[0144] 6. Based on the control objectives of the inverter, set the reference point for reactive power-voltage droop control in the VQ coordinate system and clearly mark it in the stable region map obtained in step 5.

[0145] 7. Using the aforementioned reference point as the axis, adjust the sag coefficient. Different droop control curves are plotted based on the given values. The results are then determined by analyzing whether these droop control curves have a valid intersection with the stability region graph (i.e., the intersection points are all located at the inverter grid connection point voltage). Within the allowable range, the feasible range of values ​​for the droop coefficient is determined.

[0146] 8. Based on the analysis results of step 7, determine the droop coefficient that can ensure the stable operation of the system. The critical value is obtained, which is the boundary range of the droop coefficient.

[0147] Key points of this application: 1. A method for analyzing the droop coefficient using the QV curve based on the SMIB model; 2. A method for selecting the stability boundary of the reactive power droop coefficient.

[0148] This application provides an inverter droop control method, system, electronic device, and readable storage medium. The method includes: generating an initial family of curves for reactive power and voltage on the inverter side based on an established Single-Unit Infinite Bus (SMIB) model; filtering the generated initial family of curves according to a preset power system static stability criterion to obtain a stable region map that can satisfy the stable operation of the SMIB model; setting various different droop control curves in the stable region map; and determining the boundary values ​​of the droop coefficient range based on the intersection between the droop control curves and the stable region map. By constructing an SMIB model and coupling its inherent mathematical relationships with strict stability criteria, this application can accurately identify the stable domain of the reactive power-voltage droop coefficient of a grid-connected inverter both in advance and offline, ensuring the planning, design, and safe and stable operation of the power grid.

[0149] To better implement the inverter droop control method in the embodiments of this application, an inverter droop control system is also provided in the embodiments of this application, based on the inverter droop control method. Figure 6 This is a schematic diagram of the inverter droop control system provided in the embodiments of this application, as shown below. Figure 6 As shown, the inverter droop control system includes:

[0150] The initial curve generation module 601 is used to generate an initial curve family of reactive power and voltage on the inverter side based on the established Single-Machine Infinite System (SMIB) model.

[0151] The stable region map acquisition module 602 is used to filter the generated initial curve family according to the preset power system static stability criterion to obtain a stable region map that can meet the stable operation of the SMIB model.

[0152] The droop control curve setting module 603 is used to set various different droop control curves in the stable region map.

[0153] The droop coefficient range determination module 604 is used to determine the droop coefficient range based on the intersection between the droop control curve and the stable region map;

[0154] The droop control module 605 is used to perform reactive power-voltage droop control based on the droop coefficient range.

[0155] In one example, the setting of various droop control curves in the stable region map includes:

[0156] According to the control objective of the inverter, a reference point for reactive power-voltage droop control is set in the coordinate system of the stable region map;

[0157] Using the aforementioned reference point as the axis, the value of the sag coefficient is adjusted to obtain different sag control curves.

[0158] In one example, determining the droop coefficient range based on the intersection between the droop control curve and the stable region map includes:

[0159] Determine whether there is a valid intersection between the various droop control curves and the stable region map;

[0160] The effective intersection means that all intersection points of the droop control curve and the stable region map are within the allowable range of the inverter's grid connection point voltage.

[0161] In one example, determining the droop coefficient range based on the intersection between the droop control curve and the stable region map includes:

[0162] Determine that at least one of the droop control curves has a valid intersection with the stable region map.

[0163] The minimum value of the droop coefficient corresponding to at least one droop control curve that has a valid intersection with the stable region map is determined as the boundary value of the droop coefficient range.

[0164] In one example, the step of filtering the generated initial curve family according to a preset power system static stability criterion to obtain a stable region map that can satisfy the stable operation of the SMIB model includes:

[0165] Based on the preset static stability criteria of the power system, initial curves that do not meet the static stability requirements of the power system are eliminated.

[0166] In one example, the preset power system static stability criterion includes: the power system's power angle stability and reactive voltage stability are simultaneously satisfied.

[0167] Satisfying the work angle stability:

[0168]

[0169] Satisfy reactive voltage stability:

[0170]

[0171] in, Active power Reactive power The phase angle, This represents the inverter grid connection point voltage in the SMIB model.

[0172] In one example, the active and reactive power on the inverter side satisfy the following:

[0173] (5)

[0174] (6)

[0175] in, Active power Reactive power The phase angle, To represent the inverter grid connection point voltage in the SMIB model, To represent the grid-side voltage in the SMIB model, These are the equivalent impedance parameters of the line. For composite impedance,

[0176] The initial family of curves for reactive power and voltage on the inverter side, generated based on the established Single-Unit Infinite Bus (SMIB) model, includes:

[0177] Define the grid-side voltage in the SMIB model. The value and the inverter grid connection point voltage The allowable operating range is determined by traversing different active power setpoints through equations (5) and (6). P and Calculate and generate a series of reactive power characteristics of the system under different active power injections. Q With voltage V The changing natural characteristic curves constitute the initial family of curves.

[0178] In one example, based on the established Single-Machine Infinite Block (SMIB) system model, an initial family of curves for reactive power and voltage on the inverter side is generated, including:

[0179] Based on the SMIB model, the parameters of the line equivalent impedance are calculated. , ,

[0180] in, , ,

[0181] in, This represents the resistance value. This represents the value of the reactance. This represents the numerical value of the composite impedance.

[0182] In one example, the value of the resistor The value of the reactance and the numerical value of the composite impedance. satisfy:

[0183]

[0184]

[0185]

[0186]

[0187] Where SCR is the short-circuit ratio of the power system and XRR is the reactance-resistance ratio of the power system.

[0188] also, Figure 6 The embodiments shown are only one example of the inverter droop control system, not all of them. All other embodiments obtained by those skilled in the art based on the inverter droop control system embodiments in this application without inventive effort are within the scope of protection of this application.

[0189] This application also provides a system for determining the range of the reactive power-voltage droop coefficient of an inverter, the system comprising:

[0190] The initial curve family generation module is used to generate an initial curve family of reactive power and voltage on the inverter side based on the established Single-Machine Infinite System (SMIB) model.

[0191] The stable region map acquisition module is used to filter the generated initial curve family according to the preset power system static stability criterion to obtain a stable region map that can meet the stable operation of the SMIB model.

[0192] A droop control curve setting module is used to set various droop control curves in the stable region map.

[0193] The droop coefficient range determination module is used to determine the droop coefficient range based on the intersection between the droop control curve and the stable region map.

[0194] This application also provides an electronic device, such as... Figure 7 As shown, Figure 7 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application.

[0195] In one exemplary embodiment, the electronic device integrates any of the inverter droop control systems provided in the embodiments of this application.

[0196] The electronic device includes: one or more processors; a memory; and one or more application programs, the one or more application programs being stored in the memory and configured to be executed by the processors in the steps of the inverter droop control method in any of the above embodiments.

[0197] Electronic devices may include components such as processors 701 with one or more processing cores, memories 702 with one or more readable storage media, power supplies 703, and input units 704. Those skilled in the art will understand that... Figure 7 The electronic device structure shown does not constitute a limitation on the electronic device and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0198] The processor 701 is the control center of the electronic device. It connects various parts of the electronic device via various interfaces and lines. By running or executing software programs and / or modules stored in the memory 702, and by calling data stored in the memory 702, it performs various functions and data processing of the electronic device, thereby providing overall monitoring of the electronic device. Optionally, the processor 701 may include one or more processing cores; preferably, the processor 701 may integrate an application processor and a modem processor. The application processor mainly handles the operating system, user interface, and applications, while the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into the processor 701.

[0199] The memory 702 can be used to store software programs and modules. The processor 701 executes various functional applications and data processing by running the software programs and modules stored in the memory 702. The memory 702 may mainly include a program storage area and a data storage area. The program storage area may store the operating system or application programs required for at least one function (such as sound playback function, image playback function, etc.); the data storage area may store data created according to the use of the electronic device. In addition, the memory 702 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. Accordingly, the memory 702 may also include a memory controller to provide the processor 701 with access to the memory 702.

[0200] The electronic device also includes a power supply 703 that supplies power to the various components. Preferably, the power supply 703 can be logically connected to the processor 701 through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system. The power supply 703 may also include one or more DC or AC power supplies, recharging systems, power fault detection circuits, power converters or inverters, or power status indicators, etc.

[0201] The electronic device may also include an input unit 704, which can be used to receive input digital or character information and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function control.

[0202] Although not shown, the electronic device may also include a display unit, etc., which will not be described in detail here. In an exemplary embodiment, the processor 701 in the electronic device loads the executable files corresponding to the processes of one or more application programs into the memory 702 according to the following instructions, and the processor 701 runs the application programs stored in the memory 702, thereby implementing the inverter droop control method of any of the above embodiments.

[0203] also, Figure 7 The embodiments shown are only one example of the electronic device, not all of them. All other embodiments obtained by those skilled in the art based on the electronic device embodiments in this application without any inventive effort are within the scope of protection of this application.

[0204] This application also provides an electronic device, including one that is compatible with... Figure 7 The electronic device shown is a similar component used to implement the method described above for determining the range of the inverter's reactive power-voltage droop coefficient.

[0205] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by instructions, or by instructions controlling related hardware. These instructions can be stored in a readable storage medium and loaded and executed by a processor.

[0206] Therefore, such as Figure 8 As shown, this application embodiment provides a computer-readable storage medium 800, which may include: read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk, etc. A computer program 810 is stored on the readable storage medium 800, and the computer program 810 is loaded by a processor to execute the steps in any of the inverter droop control methods provided in this application embodiment.

[0207] also, Figure 8 The embodiments shown are only one example of a computer-readable storage medium, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the computer-readable storage medium embodiments in this application without inventive effort are within the scope of protection of this application.

[0208] The inverter droop control method in this embodiment is applied to an inverter droop control system. The inverter droop control system is located in an electronic device. The electronic device has one or more processors, a memory, and one or more application programs. The one or more application programs are stored in the memory and configured to be executed by the processor to implement the inverter droop control method. The electronic device can be a terminal, such as a mobile phone or a tablet computer. The electronic device can also be a server or a service cluster composed of multiple servers.

[0209] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the detailed descriptions of other embodiments above, which will not be repeated here.

[0210] In practice, each of the above units or structures can be implemented as an independent entity or can be arbitrarily combined to be implemented as the same or several entities. For the specific implementation of each of the above units or structures, please refer to the previous method embodiments, which will not be repeated here.

[0211] For details on the implementation of each of the above operations, please refer to the previous examples, which will not be repeated here.

[0212] The inverter droop control method, system, electronic device, and readable storage medium provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for controlling inverter droop, characterized in that, include: Based on the established SMIB model of a single-machine infinite bus system, an initial family of curves for reactive power and voltage on the inverter side is generated. Based on the preset power system static stability criteria, the generated initial curve family is screened to obtain a stable region map that can satisfy the stable operation of the SMIB model. Various droop control curves are set in the stable region map; Based on the effective intersection between the droop control curve and the stable region map, the range of the droop coefficient is determined; and Based on the aforementioned droop coefficient range, reactive power-voltage droop control is performed. The effective intersection means that all intersection points of the droop control curve and the stable region map are within the allowable range of the inverter grid connection point voltage.

2. The inverter droop control method according to claim 1, characterized in that, The method of setting various droop control curves in the stable region map includes: According to the control objective of the inverter, a reference point for reactive power-voltage droop control is set in the coordinate system of the stable region map; Using the aforementioned reference point as the axis, the value of the sag coefficient is adjusted to obtain different sag control curves.

3. The inverter droop control method according to claim 1 or 2, characterized in that, The determination of the droop coefficient range based on the effective intersection between the droop control curve and the stable region map includes: Determine whether there is a valid intersection between the various droop control curves and the stable region map.

4. The inverter droop control method according to claim 3, characterized in that, The determination of the droop coefficient range based on the effective intersection between the droop control curve and the stable region map includes: Determine that at least one of the droop control curves has a valid intersection with the stable region map. The minimum value of at least one droop coefficient corresponding to at least one droop control curve that has a valid intersection with the stable region map is determined as the boundary value of the droop coefficient range.

5. The inverter droop control method according to claim 1, characterized in that, The step of filtering the generated initial curve family according to the preset power system static stability criterion to obtain a stable region map that can satisfy the stable operation of the SMIB model includes: Based on the preset static stability criteria of the power system, initial curves that do not meet the static stability requirements of the power system are eliminated.

6. The inverter droop control method according to claim 5, characterized in that, The preset static stability criteria for the power system include: the power angle stability and reactive voltage stability of the power system are simultaneously satisfied. Satisfying the work angle stability: Satisfy reactive voltage stability: in, Active power Reactive power The phase angle, This represents the inverter grid connection point voltage in the SMIB model.

7. The inverter droop control method according to claim 6, characterized in that, The active and reactive power on the inverter side meet the following requirements: （5） （6） in, Active power Reactive power The phase angle, To represent the inverter grid connection point voltage in the SMIB model, To represent the grid-side voltage in the SMIB model, These are the equivalent impedance parameters of the line. The initial family of curves for reactive power and voltage on the inverter side, generated based on the established SMIB model of a single-machine infinite bus system, includes: Define the grid-side voltage in the SMIB model. The value and the inverter grid connection point voltage The allowable operating range is determined by traversing different active power setpoints through equations (5) and (6). P and Calculate and generate a series of reactive power characteristics of the system under different active power injections. Q With voltage V The changing natural characteristic curves constitute the initial family of curves.

8. The inverter droop control method according to claim 7, characterized in that, The initial family of curves for reactive power and voltage on the inverter side, based on the established SMIB model of a single-machine infinite bus system, includes: Based on the SMIB model, the parameters of the line equivalent impedance are calculated. , , in, , , in, This represents the resistance value. This represents the value of the reactance. This represents the numerical value of the composite impedance.

9. The inverter droop control method according to claim 8, characterized in that, The value of the resistor The value of the reactance and the numerical value of the composite impedance. satisfy: Where SCR is the short-circuit ratio of the power system and XRR is the reactance-resistance ratio of the power system.

10. An inverter droop control system, characterized in that, The system includes: The initial curve family generation module is used to generate an initial curve family of reactive power and voltage on the inverter side based on the established SMIB model of a single-machine infinite bus system. The stable region map acquisition module is used to filter the generated initial curve family according to the preset power system static stability criterion to obtain a stable region map that can meet the stable operation of the SMIB model. A droop control curve setting module is used to set various droop control curves in the stable region map. The droop coefficient range determination module is used to determine the droop coefficient range based on the effective intersection between the droop control curve and the stable region map; and The droop control module is used to perform reactive power-voltage droop control based on the droop coefficient range. The effective intersection means that all intersection points of the droop control curve and the stable region map are within the allowable range of the inverter grid connection point voltage.

11. An electronic device, characterized in that, It includes a memory and a processor; the memory stores an application program, and the processor runs the application program within the memory to perform the steps of the inverter droop control method according to any one of claims 1 to 9.

12. A computer-readable storage medium, characterized in that, The readable storage medium stores instructions adapted for loading by a processor to perform the steps of the inverter droop control method according to any one of claims 1-9.

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