Frequency and moment of inertia control method and system for electrical grid with high proportion of new energy

Abstract

The present application relates to a frequency and moment of inertia control method and system for an electrical grid with a high proportion of new energy. The method comprises the following steps: establishing a virtual rotor motion equation, and performing frequency droop control on the active power therein, so as to obtain an active-frequency droop equation; substituting the active-frequency droop equation into the virtual rotor motion equation, so as to obtain a virtual governor control model, and obtaining an output reactive adjustment equation of a new energy grid-connected converter; establishing an equivalent impedance equation; on the basis of Kirchhoff's voltage law and by means of introducing a dq-axis current coupling component, obtaining a mathematical model of an output voltage of a VSG control system in a dq two-phase coordinate system, and then obtaining the output power of a VSG; using an energy composition function to analyze a transient energy change process during frequency adjustment of the VSG; according to the relationship between a current angular frequency and an initial angular frequency, introducing a frequency change rate to represent a virtual inertia, so as to obtain an adaptive virtual inertia; and substituting the adaptive virtual inertia into the virtual rotor motion equation, so as to obtain a frequency and moment of inertia control equation for an electrical grid with a high proportion of new energy.

Description

A method and system for controlling the frequency rotational inertia of a high-proportion renewable energy power grid Technical Field

[0001] This application relates to the field of energy storage control technology, and more specifically, to a method and system for controlling the frequency rotational inertia of a high-proportion renewable energy power grid. Background Technology

[0002] With the rapid development of new energy sources and the advancement of clean energy substitution, conventional synchronous generator units in the power system are being largely replaced by new energy sources. The proportion of new energy output in the power grid is continuously increasing, while the proportion of conventional generating units is steadily decreasing. This leads to a continuous reduction in the effective rotational inertia of the power system, resulting in increased risks to system frequency stability. When a system fault occurs or a significant power loss occurs, insufficient system inertia can easily trigger frequency stability issues across the entire grid. Large-scale integration of new energy sources without the ability to actively support inertia and frequency will pose a significant challenge to the safe and stable operation of the power system.

[0003] When power imbalance exists on the interconnection lines of a high-proportion renewable energy grid, the VSG control system of the renewable energy grid-connected converter responds to power changes in real time through virtual inertia and virtual damping, dynamically compensating for the unbalanced power and thus suppressing frequency fluctuations. In traditional VSG control, the virtual inertia and virtual damping are constant values. When large power fluctuations or frequency oscillations occur, it is impossible to adjust the VSG virtual parameters in real time to suppress transient impacts.

[0004] Existing technologies, such as Chinese patent number CN116667388A, disclose a method for suppressing low-frequency oscillations in power systems using a hybrid energy storage system with a flow supercapacitive lithium battery. This method establishes a reactive power-voltage regulation equation, and based on this equation, establishes a virtual excitation regulation small disturbance equation for a hybrid energy storage system using a flow supercapacitive lithium battery (VSG). Based on the energy storage converter (PCS) and the equivalent circuit topology of the VSG grid connection, it obtains the VSG output power equation and the active power-power angle small disturbance model. Based on the active power-power angle small disturbance model, the VSG output power equation, and the energy storage VSG virtual excitation regulation small disturbance equation, it obtains a virtual power angle small disturbance model, an expression for the electromagnetic torque of the energy storage VSG virtual PSS, and an equivalent damping coefficient. Finally, based on the virtual power angle small disturbance model, the expression for the electromagnetic torque of the energy storage VSG virtual PSS, and the equivalent damping coefficient, it obtains the energy storage VSG virtual PSS transfer function. In this application, the VSG virtual excitation regulator adjusts the virtual PSS through the virtual PSS transfer function, thereby improving the damping ratio of the VSG control system and suppressing low-frequency oscillations in the power system.

[0005] The problem with the above-mentioned existing technology is that the method is based on the small disturbance equation to establish the model. However, the disturbances in the actual power system may not all be small disturbances. When faced with large disturbances or sudden situations, the small disturbance model may not be able to accurately reflect the dynamic characteristics of the system, thus affecting the suppression effect on low-frequency oscillations. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a method and system for controlling the frequency rotational inertia of a high-proportion renewable energy power grid.

[0007] The technical solution of this invention is as follows:

[0008] This invention proposes a method for controlling the frequency rotational inertia of a high-proportion renewable energy power grid, comprising the following steps:

[0009] Step S1: Establish the motion equation of the virtual rotor of the VSG control for the new energy grid-connected converter; perform frequency droop control on the active power in the motion equation of the virtual rotor of the VSG control for the new energy grid-connected converter to obtain the active power-frequency droop equation.

[0010] Step S2: Substitute the active power-frequency droop equation into the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter to obtain the control model of the VSG virtual speed governor of the new energy grid-connected converter; at the same time, obtain the output reactive power regulation equation of the new energy grid-connected converter.

[0011] Step S3: Based on the equivalent circuit of the grid-connected VSG converter for the new energy grid-connected converter, establish the equivalent impedance equation of the new energy grid-connected converter; based on Kirchhoff's voltage law and introducing the dq-axis current coupling component, obtain the mathematical model of the output voltage of the VSG control system of the new energy grid-connected converter in the dq two-phase coordinate system; and then obtain the output power of the VSG when the VSG control system of the new energy grid-connected converter is running stably.

[0012] Step S4: Analyze the transient energy change process of the VSG frequency adjustment of the new energy grid-connected converter using the energy composition function; analyze the frequency adjustment rate of the new energy grid-connected converter VSG during the acceleration and deceleration phases of the virtual angular frequency according to the relationship between the current angular frequency and the initial angular frequency, introduce the frequency change rate to characterize the virtual inertia, and obtain a new type of adaptive virtual inertia.

[0013] Step S5: Substitute the novel adaptive virtual inertia into the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter to obtain the frequency rotational inertia control equation of the high-proportion new energy grid.

[0014] In a preferred embodiment, the motion equations of the virtual rotor controlled by the VSG of the new energy grid-connected converter are established, and the motion equations of the virtual rotor controlled by the VSG of the new energy grid-connected converter are expressed as follows:

[0015] Where: H is the VSG virtual inertia; D is the VSG virtual damping; δ is the VSG virtual power angular velocity; ω is the virtual electric angular velocity; ω0 is the synchronous angular velocity at the grid connection point of the new energy grid-connected converter; P m Output virtual mechanical power to VSG; P e This represents the actual output value of active power in the grid-connected converter system for new energy sources.

[0016] In a preferred embodiment, the active power-frequency droop equation is substituted into the motion equation of the virtual rotor of the VSG control in the new energy grid-connected converter to obtain the control model of the VSG virtual speed governor of the new energy grid-connected converter; wherein, the specific formula of the active power-frequency droop equation is as follows: P m =P ref +m(ω-ω0)

[0017] In the formula: m is the active power-frequency droop coefficient; P ref This represents the target value for active power.

[0018] The control model of the VSG virtual speed governor for the new energy grid-connected converter is obtained:

[0019] In the formula, s is the Laplace operator.

[0020] In a preferred embodiment, the reactive power regulation equation of the new energy grid-connected converter is obtained simultaneously; the specific calculation formula is as follows:

[0021] In the formula: n is the reactive power droop coefficient; K s T is the voltage regulation coefficient; a U is the delay constant; ref U and Q represent the grid connection point reference voltage and voltage amplitude, respectively; e Q represents the actual reactive power output of the grid-connected converter system for new energy sources. ref E represents the target value of reactive power; E represents the amplitude of the three-phase voltage output of the VSG converter for new energy grid connection.

[0022] In a preferred embodiment, the output power of the VSG is obtained when the VSG control system of the new energy grid-connected converter is running stably. The output power of the VSG is expressed as:

[0023] In the formula: e d e q These are the d-axis and q-axis voltage components of the VSG control system for a new energy grid-connected converter; i d i q δ represents the output current along the d-axis and q-axis, respectively; X represents the equivalent inductive reactance; and δ represents the VSG virtual power angular velocity.

[0024] In a preferred embodiment, the transient energy change process during VSG frequency regulation of the renewable energy grid-connected converter is analyzed using an energy composition function, wherein the specific formula of the energy composition function is as follows:

[0025] In the formula: W x W s W d The energy required for the kinetic energy, potential energy, and damping of the VSG in the grid-connected new energy converter; δ0 is the initial virtual power angle of the VSG in the grid-connected new energy converter; P δ The output power of the new energy grid-connected converter VSG when the virtual power angle is δ; The output power of the new energy grid-connected converter VSG when the virtual power angle is the initial power angle.

[0026] In a preferred embodiment, the novel adaptive virtual inertia is substituted into the motion equation of the virtual rotor of the VSG control in the new energy grid-connected converter to obtain the frequency rotational inertia control equation for high-proportion new energy grids; the specific formula is as follows:

[0027] In the formula, H i For a novel adaptive virtual inertia, D i For adaptive virtual damping.

[0028] On the other hand, the present invention also provides a high-proportion renewable energy grid frequency rotational inertia control system, comprising:

[0029] Module M1 is used to establish the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter; frequency droop control is performed on the active power in the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter to obtain the active power-frequency droop equation.

[0030] Module M2 substitutes the active power-frequency droop equation into the motion equation of the virtual rotor of the VSG control in the new energy grid-connected converter to obtain the control model of the VSG virtual speed governor of the new energy grid-connected converter; at the same time, it obtains the output reactive power regulation equation of the new energy grid-connected converter.

[0031] Module M3 establishes the equivalent impedance equation of the new energy grid-connected converter based on the VSG grid-connected equivalent circuit; based on Kirchhoff's voltage law and introducing the dq-axis current coupling component, it obtains the mathematical model of the output voltage of the VSG control system of the new energy grid-connected converter in the dq two-phase coordinate system; and then obtains the output power of the VSG when the VSG control system of the new energy grid-connected converter is running stably.

[0032] Module M4 uses energy composition functions to analyze the transient energy change process during VSG frequency regulation of the new energy grid-connected converter; according to the relationship between the current angular frequency and the initial angular frequency, it analyzes the VSG frequency regulation rate of the new energy grid-connected converter during the acceleration and deceleration phases of the virtual angular frequency, introduces the frequency change rate to characterize the virtual inertia, and obtains a new type of adaptive virtual inertia.

[0033] Module M5 is used to substitute the novel adaptive virtual inertia into the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter, so as to obtain the frequency rotational inertia control equation of the high-proportion new energy grid.

[0034] In another aspect, the present invention also provides an electronic device having a computer program stored thereon, wherein when the computer program is executed by a processor, it implements a high-proportion new energy grid frequency rotational inertia control method as described in any embodiment of the present invention.

[0035] In another aspect, the present invention also provides a computer-readable medium for storing one or more programs, which, when executed by one or more processors, cause the one or more processors to implement a high-proportion renewable energy grid frequency rotational inertia control method as described in any embodiment of the present invention.

[0036] The present invention has the following beneficial effects:

[0037] 1. Models are established for grid-connected converters for new energy sources, which focus more on the application scenarios of new energy in the power system and can better adapt to the power grid development trend of high proportion of new energy.

[0038] 2. By analyzing the transient energy change process using an energy composition function, a novel adaptive virtual inertia is obtained by introducing the frequency change rate to characterize the virtual inertia. This virtual inertia can be dynamically adjusted according to the relationship between the current angular frequency and the initial angular frequency, as well as the actual operating state of the system, thereby improving the system's response capability and stability to frequency changes under different operating conditions.

[0039] 3. When there is a power imbalance in the interconnection lines of the high-proportion renewable energy grid, the VSG control system of the renewable energy grid-connected converter responds to power changes in real time through virtual inertia and virtual damping, dynamically compensates for the unbalanced power, and achieves the purpose of suppressing frequency fluctuations.

[0040] 4. Starting with the establishment of the virtual rotor motion equation, the active power-frequency droop equation, the virtual speed governor control model, and the output reactive power regulation equation are gradually derived, covering both active and reactive power aspects, and providing a more comprehensive and systematic consideration for the control of new energy grid-connected converters. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 is a schematic diagram of the method flow of Embodiment 1;

[0043] Figure 2 shows the grid connection structure and control topology of the VSG converter for new energy grid connection;

[0044] Figure 3 is the equivalent circuit diagram of the grid-connected converter for new energy using VSG;

[0045] Figure 4 shows the curves of power angle and angular frequency variation of the VSG power angle in the grid-connected converter for new energy. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0048] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0049] The terms “comprising” and “including” indicate the presence of the described feature, whole, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0050] The term “and / or” refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes these combinations.

[0051] Example 1:

[0052] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present application and with reference to Figure 1.

[0053] To address the problems of existing technologies, this invention provides a method for controlling the frequency rotational inertia of a high-proportion renewable energy power grid, comprising the following steps:

[0054] As shown in Figure 2, C dc For DC-side filter capacitors in grid-connected converters for new energy sources; R f L f C f Construct an LCL filter circuit; e a e b e c and i abc For the VSG AC three-phase output voltage and current of the grid-connected converter for new energy; u a u b u c This refers to the three-phase voltage at the grid connection point, i.e., the grid-side voltage; L g R g This constitutes the line impedance; P e Q e These represent the actual active and reactive power output values ​​of the new energy grid-connected converter system, respectively. In the VSG control model: P ref Q ref These are the target values ​​for active and reactive power, respectively; P m The virtual mechanical power output of the VSG; δ and ω are the virtual power angle and virtual electric angular velocity of the VSG, respectively; E is the three-phase voltage output of the VSG of the new energy grid-connected converter. a e b e c Amplitude; U is the grid connection point voltage u a u b u c Amplitude; U ref This is the reference voltage at the grid connection point.

[0055] Step S1: Establish the motion equation of the virtual rotor of the VSG control for the new energy grid-connected converter; perform frequency droop control on the active power in the motion equation of the virtual rotor of the VSG control for the new energy grid-connected converter to obtain the active power-frequency droop equation.

[0056] Step S101: Establish the motion equation of the virtual rotor for VSG control of the new energy grid-connected converter;

[0057] The motion equation of the virtual rotor for VSG control in a new energy grid-connected converter is expressed as:

[0058] Where: H is the VSG virtual inertia; D is the VSG virtual damping; δ is the VSG virtual power angular velocity; ω is the virtual electric angular velocity; ω0 is the synchronous angular velocity at the grid connection point of the new energy grid-connected converter; P m Output virtual mechanical power to VSG; P e This represents the actual output value of active power in the grid-connected converter system for new energy sources.

[0059] Step S102: Frequency droop control is applied to the active power in the virtual rotor motion equation of the VSG control system for the new energy grid-connected converter, resulting in the active power-frequency droop equation. This enables the VSG to have frequency regulation capability. The active power-frequency droop control equation can be expressed as: P m =P ref +m(ω-ω0)

[0060] In the formula: m is the active power-frequency droop coefficient; P ref This represents the target value for active power.

[0061] Step S2: Substitute the active power-frequency droop equation into the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter to obtain the control model of the VSG virtual speed governor of the new energy grid-connected converter; at the same time, obtain the output reactive power regulation equation of the new energy grid-connected converter.

[0062] Step S201 yields the control model of the VSG virtual speed governor for the new energy grid-connected converter, as shown in the following formula:

[0063] In the formula, s is the Laplace operator.

[0064] Step S202: The voltage amplitude is regulated by the VSG-simulated synchronous generator excitation current control method. Based on the motion equation of the virtual rotor controlled by the VSG of the new energy grid-connected converter, the reactive power regulation equation of the new energy grid-connected converter output is obtained as follows:

[0065] In the formula: n is the reactive power droop coefficient; K s T is the voltage regulation coefficient; a U is the delay constant; ref U and Q represent the grid connection point reference voltage and voltage amplitude, respectively; e Q represents the actual reactive power output of the grid-connected converter system for new energy sources. ref E represents the target value of reactive power; E represents the amplitude of the three-phase voltage output of the VSG converter for new energy grid connection.

[0066] Step S3: Based on the equivalent circuit of the grid-connected VSG converter for the new energy grid-connected converter, establish the equivalent impedance equation of the new energy grid-connected converter; based on Kirchhoff's voltage law and introducing the dq-axis current coupling component, obtain the mathematical model of the output voltage of the VSG control system of the new energy grid-connected converter in the dq two-phase coordinate system; and then obtain the output power of the VSG when the VSG control system of the new energy grid-connected converter is running stably.

[0067] Step S301: Based on the VSG grid-connected equivalent circuit of the new energy grid-connected converter, establish the equivalent impedance equation of the new energy grid-connected converter; the specific formula is as follows: Z=R+jX=Z f +Z g =(R f +R g )+j(X f +X g )

[0068] In the formula: Z is the equivalent impedance; R is the equivalent resistance; X is the equivalent inductive reactance; Z f Z g These are the output impedance of the new energy grid-connected converter and the transmission line impedance, respectively; R f R g These are the output resistance of the new energy grid-connected converter and the transmission line resistance, respectively; X f X g These are the output inductive reactance of the new energy grid-connected converter and the inductive reactance of the transmission line, respectively.

[0069] Step 302: Based on Kirchhoff's voltage law and by introducing the dq-axis current coupling component, a mathematical model of the output voltage of the VSG control system of the new energy grid-connected converter in the dq two-phase coordinate system is obtained.

[0070] According to Figure 4, based on Kirchhoff's voltage law, we can obtain:

[0071] In the formula: L is the equivalent inductance of the grid-connected converter for new energy; u abc This refers to the three-phase voltage at the grid connection point, i.e., the grid-side voltage; e abc i abc R represents the AC three-phase output voltage and current of the VSG converter for new energy grid connection; R represents the equivalent resistance of the new energy grid connection converter.

[0072] Define T abc→dq0 By introducing the dq-axis current coupling component into the Park transformation matrix, we obtain the mathematical model of the output voltage of the VSG control system of the new energy grid-connected converter in the dq two-phase coordinate system:

[0073] In the formula: e d e qThese are the d-axis and q-axis voltage components of the VSG control system for a new energy grid-connected converter; i d u d These represent the d-axis output current and voltage, respectively; i q u q These represent the q-axis output current and voltage, respectively.

[0074] The output voltage of the VSG converter for new energy grid-connected power supplies and the grid-connected voltage have the following relationship:

[0075] In the formula, E is the amplitude of the three-phase voltage output of the VSG converter for new energy grid connection.

[0076] Step S303: Based on the mathematical model of the output voltage of the VSG control system of the new energy grid-connected converter in the dq two-phase coordinate system, the output power of the VSG is obtained when the VSG control system of the new energy grid-connected converter is running stably.

[0077] The output power of the VSG during stable operation of the VSG control system of the grid-connected new energy converter is expressed as:

[0078] Step S4: Analyze the transient energy change process of the VSG frequency adjustment of the new energy grid-connected converter using the energy composition function; analyze the frequency adjustment rate of the new energy grid-connected converter VSG during the acceleration and deceleration phases of the virtual angular frequency according to the relationship between the current angular frequency and the initial angular frequency, introduce the frequency change rate to characterize the virtual inertia, and obtain a new type of adaptive virtual inertia.

[0079] Step S401, as shown in Figure 4, this invention uses an energy composition function to analyze the transient energy change process during VSG frequency regulation of the new energy grid-connected converter. The energy composition function of the new energy grid-connected converter VSG can be expressed as:

[0080] In the formula: W x W s W d The energy required for the kinetic energy, potential energy, and damping of the VSG in the grid-connected new energy converter; δ0 is the initial virtual power angle of the VSG in the grid-connected new energy converter; P δ The output power of the new energy grid-connected converter VSG when the virtual power angle is δ; The output power of the new energy grid-connected converter VSG when the virtual power angle is the initial power angle.

[0081] Step S402: Based on the relationship between the current angular frequency and the initial angular frequency, and according to the energy composition function of the VSG frequency adjustment of the new energy grid-connected converter, analyze the rate of change of the VSG frequency adjustment of the new energy grid-connected converter during the acceleration and deceleration phases of the virtual angular frequency, introduce the frequency change rate to characterize the virtual inertia, and obtain a new type of adaptive virtual inertia.

[0082] Step S403: When the VSG frequency of the new energy grid-connected converter is adjusted, according to the relationship between ω and ω0, it can be divided into two stages: ω>ω0 and ω<ω0. The ω>ω0 stage includes stage a and stage b, where in stage a, dω / dt>0, and in stage b, dω / dt<0. The ω<ω0 stage includes stage c and stage d, where in stage c, dω / dt<0, and in stage d, dω / dt>0. In stage a, W... d Gradually increase, W s Gradually decreasing, it enters stage b under the influence of kinetic energy, W d Gradually decrease, W s The energy gradually increases and reciprocates under the influence of potential energy. Consider the VSG damping effect; the energy W... d Total energy W of VSG frequency regulation for new energy grid-connected converters z During the oscillation process, the frequency regulation of the VSG in the new energy grid-connected converter gradually decreases until it stabilizes.

[0083] Step S404: Based on this, the present invention proposes a method to increase the virtual moment of inertia H in stages a and d, i.e., the virtual angular frequency acceleration stage, to constrain the increase of the virtual angular frequency and reduce the virtual angular frequency adjustment deviation. Simultaneously, the virtual damping coefficient D is increased to reduce the virtual angular frequency overshoot and suppress frequency oscillation instability caused by excessive virtual moment of inertia H. In stages b and c, i.e., the virtual angular frequency deceleration stage, the virtual moment of inertia H is reduced to allow the frequency to quickly recover to a stable value. At the same time, the virtual damping coefficient D is reduced to decrease the dynamic adjustment time of the VSG control system of the new energy grid-connected converter, enabling the VSG frequency adjustment of the new energy grid-connected converter to stabilize more quickly.

[0084] Step S405: This invention introduces the frequency change rate to characterize virtual inertia. The novel adaptive virtual inertia can be expressed as:

[0085] Where: H0 is the initial value of the virtual inertia of the VSG of the new energy grid-connected converter, corresponding to the rated virtual inertia when it does not participate in frequency regulation; k i This is the virtual inertia adjustment coefficient.

[0086] Step S5: Substitute the novel adaptive virtual inertia into the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter to obtain the frequency rotational inertia control equation of the high-proportion new energy grid.

[0087] The frequency rotational inertia control equation for a high-proportion renewable energy power grid; the specific formula is as follows:

[0088] In the formula, H i For a novel adaptive virtual inertia, D i For adaptive virtual damping.

[0089] When the new virtual inertia H i Adaptive adjustment, adaptive virtual damping D i According to H i Automatic adjustment, H i and D i Joint and coordinated control effectively reduces the oscillation frequency of the VSG during the frequency regulation of the grid-connected new energy converter, and maintains the stability of the VSG frequency regulation.

[0090] Example 2:

[0091] This embodiment provides a high-proportion renewable energy grid frequency rotational inertia control system, including:

[0092] Module M1 is used to establish the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter; frequency droop control is performed on the active power in the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter to obtain the active power-frequency droop equation.

[0093] Module M2 substitutes the active power-frequency droop equation into the motion equation of the virtual rotor of the VSG control in the new energy grid-connected converter to obtain the control model of the VSG virtual speed governor of the new energy grid-connected converter; at the same time, it obtains the output reactive power regulation equation of the new energy grid-connected converter.

[0094] Module M3 establishes the equivalent impedance equation of the new energy grid-connected converter based on the VSG grid-connected equivalent circuit; based on Kirchhoff's voltage law and introducing the dq-axis current coupling component, it obtains the mathematical model of the output voltage of the VSG control system of the new energy grid-connected converter in the dq two-phase coordinate system; and then obtains the output power of the VSG when the VSG control system of the new energy grid-connected converter is running stably.

[0095] Module M4 uses energy composition functions to analyze the transient energy change process during VSG frequency regulation of the new energy grid-connected converter; according to the relationship between the current angular frequency and the initial angular frequency, it analyzes the VSG frequency regulation rate of the new energy grid-connected converter during the acceleration and deceleration phases of the virtual angular frequency, introduces the frequency change rate to characterize the virtual inertia, and obtains a new type of adaptive virtual inertia.

[0096] Module M5 is used to substitute the novel adaptive virtual inertia into the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter, so as to obtain the frequency rotational inertia control equation of the high-proportion new energy grid.

[0097] Example 3:

[0098] This embodiment provides an electronic device that stores a computer program. When the computer program is executed by a processor, it implements a high-proportion new energy grid frequency rotational inertia control method as described in any embodiment of the present invention.

[0099] Example 4:

[0100] This embodiment provides a computer-readable medium for storing one or more programs, which, when executed by one or more processors, cause the one or more processors to implement a high-proportion renewable energy grid frequency rotational inertia control method as described in any embodiment of the present invention.

[0101] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0102] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0103] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0104] In the several embodiments provided in this application, any function, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0105] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for controlling the frequency rotational inertia of a high-proportion renewable energy power grid, characterized in that, Includes the following steps: Step S1: Establish the motion equation of the virtual rotor of the VSG control for the new energy grid-connected converter; perform frequency droop control on the active power in the motion equation of the virtual rotor of the VSG control for the new energy grid-connected converter to obtain the active power-frequency droop equation. Step S2: Substitute the active power-frequency droop equation into the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter to obtain the control model of the VSG virtual speed governor of the new energy grid-connected converter; at the same time, obtain the output reactive power regulation equation of the new energy grid-connected converter. Step S3: Based on the equivalent circuit of the grid-connected VSG converter for the new energy grid-connected converter, establish the equivalent impedance equation of the new energy grid-connected converter; based on Kirchhoff's voltage law and introducing the dq-axis current coupling component, obtain the mathematical model of the output voltage of the VSG control system of the new energy grid-connected converter in the dq two-phase coordinate system; and then obtain the output power of the VSG when the VSG control system of the new energy grid-connected converter is running stably. Step S4: Analyze the transient energy change process of the VSG frequency adjustment of the new energy grid-connected converter using the energy composition function; analyze the frequency adjustment rate of the new energy grid-connected converter VSG during the acceleration and deceleration phases of the virtual angular frequency according to the relationship between the current angular frequency and the initial angular frequency, introduce the frequency change rate to characterize the virtual inertia, and obtain a new type of adaptive virtual inertia. Step S5: Substitute the novel adaptive virtual inertia into the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter to obtain the frequency rotational inertia control equation of the high-proportion new energy grid.

2. The method for controlling the frequency rotational inertia of a high-proportion new energy power grid according to claim 1, characterized in that, The motion equations for the virtual rotor of the VSG control system in the new energy grid-connected converter are established as follows: Where: H is the VSG virtual inertia; D is the VSG virtual damping; δ is the VSG virtual power angular velocity; ω is the virtual electric angular velocity; ω0 is the synchronous angular velocity at the grid connection point of the new energy grid-connected converter; P m Output virtual mechanical power to VSG; P e This represents the actual output value of active power in the grid-connected converter system for new energy sources.

3. The method for controlling the frequency rotational inertia of a high-proportion new energy power grid according to claim 1, characterized in that: The active power-frequency droop equation is substituted into the motion equation of the virtual rotor of the VSG control in the new energy grid-connected converter to obtain the control model of the VSG virtual speed governor of the new energy grid-connected converter; the specific formula of the active power-frequency droop equation is as follows: P m =P ref +m(ω-ω0) In the formula: m is the active power-frequency droop coefficient; P ref This represents the target value for active power. The control model of the VSG virtual speed governor for the new energy grid-connected converter is obtained: In the formula, s is the Laplace operator.

4. The method for controlling the frequency rotational inertia of a high-proportion new energy power grid according to claim 1, characterized in that: The reactive power regulation equation for the output of the new energy grid-connected converter is obtained simultaneously; the specific calculation formula is as follows: In the formula: n is the reactive power droop coefficient; K s T is the voltage regulation coefficient; a U is the delay constant; ref U and Q represent the grid connection point reference voltage and voltage amplitude, respectively; e Q represents the actual reactive power output of the grid-connected converter system for new energy sources. ref E represents the target value of reactive power; E represents the amplitude of the three-phase voltage output of the VSG converter for new energy grid connection.

5. The method for controlling the frequency rotational inertia of a high-proportion new energy power grid according to claim 1, characterized in that: The output power of the VSG is then obtained when the VSG control system of the new energy grid-connected converter is running stably. The output power of the VSG is expressed as: In the formula: e d e q These are the d-axis and q-axis voltage components of the VSG control system for a new energy grid-connected converter; i d i q δ represents the output current along the d-axis and q-axis, respectively; X represents the equivalent inductive reactance; and δ represents the VSG virtual power angular velocity.

6. The method for controlling the frequency rotational inertia of a high-proportion new energy power grid according to claim 1, characterized in that: The analysis of transient energy change during VSG frequency regulation in a renewable energy grid-connected converter using an energy composition function is described below. In the formula: W x W s W d The energy required for the kinetic energy, potential energy, and damping of the VSG in the grid-connected new energy converter; δ0 is the initial virtual power angle of the VSG in the grid-connected new energy converter; P δ The output power of the new energy grid-connected converter VSG when the virtual power angle is δ; The output power of the new energy grid-connected converter VSG when the virtual power angle is the initial power angle.

7. The method for controlling the frequency rotational inertia of a high-proportion new energy power grid according to claim 1, characterized in that: The novel adaptive virtual inertia is substituted into the motion equation of the virtual rotor control VSG of the renewable energy grid-connected converter to obtain the frequency rotational inertia control equation for high-proportion renewable energy grids; the specific formula is as follows: In the formula, H i For a novel adaptive virtual inertia, D i For adaptive virtual damping.

8. A frequency rotational inertia control system for high-proportion new energy power grids, characterized in that, include: Module M1 is used to establish the motion equations of the virtual rotor for VSG control in new energy grid-connected converters; By applying frequency droop control to the motion equation of the virtual rotor of the VSG control in the grid-connected converter of new energy, the active power-frequency droop equation is obtained. Module M2 substitutes the active power-frequency droop equation into the motion equation of the virtual rotor of the VSG control in the new energy grid-connected converter to obtain the control model of the VSG virtual speed governor of the new energy grid-connected converter; at the same time, it obtains the output reactive power regulation equation of the new energy grid-connected converter. Module M3 establishes the equivalent impedance equation of the new energy grid-connected converter based on the VSG grid-connected equivalent circuit; based on Kirchhoff's voltage law and introducing the dq-axis current coupling component, it obtains the mathematical model of the output voltage of the VSG control system of the new energy grid-connected converter in the dq two-phase coordinate system; and then obtains the output power of the VSG when the VSG control system of the new energy grid-connected converter is running stably. Module M4 uses energy composition functions to analyze the transient energy change process during VSG frequency regulation of the new energy grid-connected converter; according to the relationship between the current angular frequency and the initial angular frequency, it analyzes the VSG frequency regulation rate of the new energy grid-connected converter during the acceleration and deceleration phases of the virtual angular frequency, introduces the frequency change rate to characterize the virtual inertia, and obtains a new type of adaptive virtual inertia. Module M5 is used to substitute the novel adaptive virtual inertia into the motion equation of the virtual rotor of the VSG control of the new energy grid-connected converter, so as to obtain the frequency rotational inertia control equation of the high-proportion new energy grid.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements a high-proportion new energy power grid frequency rotational inertia control method as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements a high-proportion new energy power grid frequency rotational inertia control method as described in any one of claims 1 to 7.

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