High-proportion new energy power grid frequency rotational inertia control method and system

Abstract

The invention relates to a high-proportion new energy power grid frequency rotational inertia control method and system. The method comprises the following steps: establishing a virtual rotor motion equation; performing frequency droop control on the active power to obtain an active-frequency droop equation; the active-frequency droop equation is substituted into the virtual rotor motion equation, and a virtual speed regulator control model is obtained; meanwhile, an output reactive power regulation equation of the new energy grid-connected current converter is obtained; establishing an equivalent impedance equation; based on the Kirchhoff voltage law and introducing a dq-axis current coupling component, obtaining a mathematical model of the output voltage of the VSG control system in a dq two-phase coordinate system; the output power of the VSG is further obtained; analyzing a transient energy change process during VSG frequency regulation by adopting an energy composition function; according to the relation between the current angular frequency and the initial angular frequency, the frequency change rate is introduced to represent the virtual inertia, and the self-adaptive virtual inertia is obtained; and the adaptive virtual inertia is substituted into the virtual rotor motion equation to obtain a high-proportion new energy power grid frequency rotational inertia control equation.

Description

Technical Field

[0001] The present application relates to the field of energy storage control technology, and more specifically, to a frequency rotation inertia control method and system for a high-proportion new energy power grid. Background Art

[0002] With the rapid development of new energy and the advancement of clean energy substitution, conventional synchronous generators in the power system have been replaced by new energy in large quantities. The output of new energy in the power grid continues to increase, and the proportion of conventional units continues to decrease, causing the effective rotational inertia of the power system to continue to decrease, resulting in an increase in the risk of system frequency stability. When the system fails or there is a large power loss, the insufficient system inertia can easily cause frequency stability problems in the entire network. Large-scale new energy access that does not have the ability to actively support inertia and frequency will bring huge challenges to the safe and stable operation of the power system.

[0003] When there is power imbalance in the interconnection lines connected to 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 links, dynamically compensates for unbalanced power, and achieves the purpose of suppressing frequency fluctuations. In traditional VSG control, virtual inertia and virtual damping are fixed values. When large power fluctuations and frequency oscillations occur, it is impossible to adjust the VSG virtual parameters in real time to suppress transient shocks.

[0004] Existing technologies such as the Chinese patent with patent number "CN116667388A" disclose a method for suppressing low-frequency oscillation of power system by hybrid energy storage of liquid supercapacitor lithium battery. This method establishes a reactive-voltage regulation equation, and establishes a virtual excitation regulation small disturbance equation of hybrid energy storage VSG of liquid supercapacitor lithium battery based on the reactive-voltage regulation equation; based on the energy storage converter PCS and using the VSG grid-connected equivalent circuit topology, the VSG output power equation and the active power-power angle small disturbance model are obtained; 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, the virtual power angle small disturbance model, the energy storage VSG virtual PSS electromagnetic torque expression and the equivalent damping coefficient are obtained; based on the virtual power angle small disturbance model, the energy storage VSG virtual PSS electromagnetic torque expression and the equivalent damping coefficient, the energy storage VSG virtual PSS transfer function is obtained. In the present 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 further suppressing the low-frequency oscillation of the power system.

[0005] The problem with the above-mentioned prior art is that this method establishes a model based on the small disturbance equation. The disturbances in the actual power system may not all be small disturbances. When faced with larger disturbances or emergencies, the small disturbance model may not accurately reflect the dynamic characteristics of the system, thereby affecting the suppression effect of low-frequency oscillations. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a frequency rotation inertia control method and system for a high-proportion new energy power grid.

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

[0008] The present invention proposes a method for controlling the frequency moment of inertia of a high-proportion new energy power grid, comprising the following steps:

[0009] Step S1, establishing a virtual rotor motion equation for controlling a new energy grid-connected converter VSG; performing frequency droop control on the active power in the virtual rotor motion equation for controlling a new energy grid-connected converter VSG to obtain an active power-frequency droop equation;

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

[0011] Step S3, according to the VSG grid-connected equivalent circuit adopted by 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 in stable operation;

[0012] Step S4, using the energy composition function to analyze the transient energy change process of the new energy grid-connected converter VSG when the frequency is adjusted; according to the relationship between the current angular frequency and the initial angular frequency, analyzing the frequency adjustment change rate of the new energy grid-connected converter VSG in the acceleration and deceleration stages of the virtual angular frequency, introducing the frequency change rate to characterize the virtual inertia, and obtaining a new adaptive virtual inertia;

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

[0014] As a preferred implementation, the virtual rotor motion equation of the new energy grid-connected converter VSG is established, and the virtual rotor motion equation of the new energy grid-connected converter VSG is expressed as:

[0015]

[0016] Where: H is the virtual inertia of VSG; D is the virtual damping of VSG; δ is the virtual power angular velocity of VSG; ω is the virtual electrical angular velocity; ω 0P is the synchronous angular velocity of the grid-connected converter of the new energy grid; m Output virtual mechanical power for VSG; P e It is the actual output value of active power of the new energy grid-connected converter system.

[0017] As a preferred implementation, the active power-frequency droop equation is introduced into the virtual rotor motion equation of the new energy grid-connected converter VSG to obtain the virtual speed regulator control model of the new energy grid-connected converter VSG; wherein, the specific formula of the active power-frequency droop equation is as follows:

[0018] P m =P ref +m(ω-ω 0 )

[0019] Where: m is the active power-frequency droop coefficient; P ref is the active power target value;

[0020] The control model of the VSG virtual speed regulator of the new energy grid-connected converter is obtained:

[0021]

[0022] Where s is the Laplace operator.

[0023] As a preferred implementation, the reactive power regulation equation of the new energy grid-connected converter output is obtained at the same time; the specific calculation formula is as follows:

[0024]

[0025] Where: n is the reactive power droop coefficient; K s is the voltage regulation coefficient; T a is the delay constant; U ref , U are the grid connection point reference voltage and voltage amplitude respectively; Q e is the actual output value of reactive power of the new energy grid-connected converter system; Q ref is the reactive power target value; E is the output three-phase voltage amplitude of the new energy grid-connected converter VSG.

[0026] As a preferred implementation, the output power of the VSG when the VSG control system of the new energy grid-connected converter is in stable operation is obtained. The output power of the VSG is expressed as:

[0027]

[0028] Where: e d 、e q They are the d-axis and q-axis voltage components of the VSG control system of the new energy grid-connected converter; i d 、i qare the d-axis and q-axis output currents respectively; X is the equivalent inductive reactance; δ is the VSG virtual power angular velocity.

[0029] As a preferred implementation, the energy composition function is used to analyze the transient energy change process when the frequency of the new energy grid-connected converter VSG is adjusted, wherein the specific formula of the energy composition function is as follows:

[0030]

[0031] Where: W x , W s , W d The energy required for the kinetic energy, potential energy and damping of the new energy grid-connected converter VSG; δ 0 P is the initial virtual power angle of the new energy grid-connected converter VSG; δ is the output power of the new energy grid-connected converter VSG when the virtual power angle is δ; When the virtual power angle is the initial power angle, the new energy grid-connected converter VSG output power.

[0032] As a preferred implementation, the novel adaptive virtual inertia is substituted into the new energy grid-connected converter VSG to control the virtual rotor motion equation, and the frequency rotation inertia control equation of the high-proportion new energy grid is obtained; the specific formula is as follows:

[0033]

[0034] In the formula, H i is a new adaptive virtual inertia, D i is the adaptive virtual damping.

[0035] On the other hand, the present invention also provides a frequency inertia control system for a high-proportion renewable energy grid, comprising:

[0036] Module M1 is used to establish a virtual rotor motion equation for a new energy grid-connected converter VSG to control the active power in the virtual rotor motion equation for the new energy grid-connected converter VSG to control the frequency droop, and obtain an active power-frequency droop equation;

[0037] Module M2, brings the active power-frequency droop equation into the virtual rotor motion equation of the new energy grid-connected converter VSG control, and obtains the new energy grid-connected converter VSG virtual speed regulator control model; at the same time, obtains the new energy grid-connected converter output reactive power regulation equation;

[0038] Module M3, based on the VSG grid-connected equivalent circuit adopted by the new energy grid-connected converter, establishes 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, 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 in stable operation;

[0039] Module M4 uses energy composition function to analyze the transient energy change process of the VSG frequency of the new energy grid-connected converter during frequency adjustment; according to the relationship between the current angular frequency and the initial angular frequency, the frequency adjustment change rate of the VSG frequency of the new energy grid-connected converter during the acceleration and deceleration stages of the virtual angular frequency is analyzed, and the frequency change rate is introduced to characterize the virtual inertia to obtain a new adaptive virtual inertia;

[0040] Module M5 is used to substitute the new adaptive virtual inertia into the virtual rotor motion equation of the new energy grid-connected converter VSG to obtain the frequency rotation inertia control equation of the high-proportion new energy grid.

[0041] On the other hand, the present invention further provides an electronic device having a computer program stored thereon, wherein when the computer program is executed by a processor, the method for controlling the frequency rotation inertia of a high-proportion new energy power grid as described in any embodiment of the present invention is implemented.

[0042] On the other hand, the present invention also provides a computer-readable medium for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement a frequency rotation inertia control method for a high-proportion new energy power grid as described in any embodiment of the present invention.

[0043] The present invention has the following beneficial effects:

[0044] 1. Establish a model for new energy grid-connected converters, focus more on the application scenarios of new energy in the power system, and better adapt to the development trend of power grids with a high proportion of new energy.

[0045] 2. By using the energy composition function to analyze the transient energy change process, the frequency change rate is introduced to characterize the virtual inertia to obtain a new adaptive virtual inertia. The virtual inertia can be dynamically adjusted according to the relationship between the current angular frequency and the initial angular frequency and the actual operating status of the system, thereby improving the system's response capability and stability to frequency changes under different working conditions.

[0046] 3. When there is power imbalance in the interconnection lines connected to 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 links, dynamically compensates for unbalanced power, and achieves the purpose of suppressing frequency fluctuations.

[0047] 4. Starting from the establishment of the virtual rotor motion equation, the active power-frequency droop equation, virtual speed regulator control model, output reactive power regulation equation, etc. are gradually derived, covering the two important aspects of active and reactive power, and the control consideration of the new energy grid-connected converter is more comprehensive and systematic. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 This is a schematic diagram of the method flow of Example 1;

[0050] Figure 2 The grid-connected structure and control topology diagram of the new energy grid-connected converter VSG;

[0051] Figure 3 The VSG grid-connected equivalent circuit diagram is used for the new energy grid-connected converter;

[0052] Figure 4 The curve diagram of the change of power angle and angular frequency of VSG used in the new energy grid-connected converter. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

[0055] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0056] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0057] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0058] Embodiment 1:

[0059] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following will be combined with the specific embodiments of the present application and refer to the attached Figure 1 , clearly and completely describe the technical solution of the present invention.

[0060] In order to solve the problems of the prior art, the present invention provides a method for controlling the frequency moment of inertia of a high-proportion new energy power grid, comprising the following steps:

[0061] like Figure 2 As shown, C dc It is the DC side filter capacitor of the new energy grid-connected converter; R f , L f , C f Constitute the LCL filter circuit; a 、e b 、e c and i abc is the AC three-phase output voltage and current of the new energy grid-connected converter VSG; u a 、u b 、u c is the three-phase voltage at the grid connection point, i.e., the grid side voltage; L g , R g The line impedance is P e , Q e are respectively the actual output values ​​of active and reactive power of the new energy grid-connected converter system. In the VSG control model: ref , Q ref are active power and reactive power target values ​​respectively; P m is the virtual mechanical power output by VSG; δ and ω are the virtual power angle and virtual electrical angular velocity of VSG respectively; E is the three-phase voltage output by the new energy grid-connected converter VSG e a 、e b 、e c Amplitude; U is the grid connection point voltage u a 、u b 、u c Amplitude; U ref It is the reference voltage of the grid connection point.

[0062] Step S1, establishing a virtual rotor motion equation for controlling a new energy grid-connected converter VSG; performing frequency droop control on the active power in the virtual rotor motion equation for controlling a new energy grid-connected converter VSG to obtain an active power-frequency droop equation;

[0063] Step S101, establishing a virtual rotor motion equation for controlling a new energy grid-connected converter VSG;

[0064] The virtual rotor motion equation of the VSG control of the new energy grid-connected converter is expressed as:

[0065]

[0066] Where: H is the virtual inertia of VSG; D is the virtual damping of VSG; δ is the virtual power angular velocity of VSG; ω is the virtual electrical angular velocity; ω 0 P is the synchronous angular velocity of the grid-connected converter of the new energy grid; m Output virtual mechanical power for VSG; P e It is the actual output value of active power of the new energy grid-connected converter system.

[0067] Step S102, the frequency droop control is performed on the active power in the virtual rotor motion equation of the new energy grid-connected converter VSG to obtain the active power-frequency droop equation, so that the new energy grid-connected converter VSG has the frequency regulation capability; the active power-frequency droop scheme control equation can be expressed as:

[0068] P m =P ref +m(ω-ω 0 )

[0069] Where: m is the active power-frequency droop coefficient; P ref is the active power target value.

[0070] Step S2, bringing the active power-frequency droop equation into the virtual rotor motion equation of the new energy grid-connected converter VSG control to obtain the new energy grid-connected converter VSG virtual speed regulator control model; and at the same time, obtaining the new energy grid-connected converter output reactive power regulation equation;

[0071] Step S201, obtain the new energy grid-connected converter VSG virtual speed regulator control model, specifically as follows:

[0072]

[0073] Where s is the Laplace operator.

[0074] Step S202, VSG simulates the synchronous generator excitation current control mode to achieve voltage amplitude regulation, and according to the new energy grid-connected converter VSG control virtual rotor motion equation, the new energy grid-connected converter output reactive power regulation equation is obtained as follows:

[0075]

[0076] Where: n is the reactive power droop coefficient; K s is the voltage regulation coefficient; Ta is the delay constant; U ref , U are the grid connection point reference voltage and voltage amplitude respectively; Q e is the actual output value of reactive power of the new energy grid-connected converter system; Q ref is the reactive power target value; E is the output three-phase voltage amplitude of the new energy grid-connected converter VSG.

[0077] Step S3, according to the VSG grid-connected equivalent circuit adopted by 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 in stable operation;

[0078] Step S301, according to the VSG grid-connected equivalent circuit adopted by the new energy grid-connected converter, an equivalent impedance equation of the new energy grid-connected converter is established; the specific formula is as follows:

[0079] Z=R+jX=Z f +Z g

[0080] =(R f +R g )+j(X f +X g )

[0081] Where: Z is equivalent impedance; R is equivalent resistance; X is equivalent inductive reactance; Z f , Z f are the output impedance of the new energy grid-connected converter and the transmission line impedance respectively; R f , R g are the output resistance of the new energy grid-connected converter and the resistance of the transmission line; X f , X g They are the output inductance of the new energy grid-connected converter and the inductance of the transmission line.

[0082] Step 302, based on Kirchhoff's voltage law and 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;

[0083] according to Figure 4 , based on Kirchhoff's voltage law:

[0084]

[0085] Where: L is the equivalent inductance of the new energy grid-connected converter; u abc is the three-phase voltage at the grid connection point, i.e., the grid-side voltage; e abc、i abc is the AC three-phase output voltage and current of the new energy grid-connected converter VSG; R is the equivalent resistance of the new energy grid-connected converter;

[0086] Define T abc→dq0 The Park transformation matrix is ​​introduced, and the dq axis current coupling component is introduced to 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:

[0087]

[0088] Where: e d 、e q They are the d-axis and q-axis voltage components of the VSG control system of the new energy grid-connected converter; i d 、u d are the d-axis output current and voltage respectively; i q 、u q They are the q-axis output current and voltage respectively;

[0089] The output voltage of the new energy grid-connected converter VSG and the grid-connected voltage have the following relationship:

[0090]

[0091] Where E is the output three-phase voltage amplitude of the new energy grid-connected converter VSG.

[0092] Step S303, according to 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 when the VSG control system of the new energy grid-connected converter is in stable operation is obtained;

[0093] The output power of VSG when the VSG control system of the new energy grid-connected converter is running stably. The output power of VSG is expressed as:

[0094]

[0095] Step S4, using the energy composition function to analyze the transient energy change process of the new energy grid-connected converter VSG when the frequency is adjusted; according to the relationship between the current angular frequency and the initial angular frequency, analyzing the frequency adjustment change rate of the new energy grid-connected converter VSG in the acceleration and deceleration stages of the virtual angular frequency, introducing the frequency change rate to characterize the virtual inertia, and obtaining a new adaptive virtual inertia;

[0096] Step S401, as Figure 4 As shown, the present invention adopts energy composition function to analyze the transient energy change process of the new energy grid-connected converter VSG when the frequency is adjusted. The energy composition function of the new energy grid-connected converter VSG can be expressed as:

[0097]

[0098] Where: W x , W s , W d The energy required for the kinetic energy, potential energy and damping of the new energy grid-connected converter VSG; δ 0 P is the initial virtual power angle of the new energy grid-connected converter VSG; δ is the output power of the new energy grid-connected converter VSG when the virtual power angle is δ; When the virtual power angle is the initial power angle, the new energy grid-connected converter VSG output power.

[0099] Step S402, according to the relationship between the current angular frequency and the initial angular frequency, and based on the energy composition function of the frequency adjustment of the new energy grid-connected converter VSG, the frequency adjustment change rate of the new energy grid-connected converter VSG in the virtual angular frequency acceleration and deceleration stages is analyzed, and the frequency change rate is introduced to characterize the virtual inertia, so as to obtain a new adaptive virtual inertia;

[0100] Step S403, when the frequency of the new energy grid-connected converter VSG is adjusted, according to ω and ω 0 The relationship can be divided into: ω>ω 0 Phase and ω<ω 0 stage. 0 The stages include stage a and stage b, where: stage a dω / dt>0, stage b dω / dt<0. ω<ω 0 The stages include stage c and stage d, where: stage c dω / dt<0; stage d ω / dt>0. In stage a, W d Gradually increasing, W s Gradually decreases, and enters stage b under the action of kinetic energy, W d Gradually decrease, W s Gradually increases, and reciprocates under the action of potential energy. Considering the VSG damping effect energy W d , new energy grid-connected converter VSG frequency regulation total energy W z It gradually decreases during the oscillation process, and the frequency regulation of the new energy grid-connected converter VSG tends to be stable until the frequency stabilizes.

[0101] Step S404, based on this, the present invention proposes a method of increasing the virtual moment of inertia H in the a stage and the d stage, that is, the virtual angular frequency acceleration stage, to constrain the increase of the virtual angular frequency, reduce the virtual angular frequency adjustment deviation, and simultaneously increase the virtual damping coefficient D to reduce the virtual angular frequency overshoot, and suppress the frequency oscillation instability caused by the excessive virtual moment of inertia H. In the b stage and the c stage, that is, the virtual angular frequency deceleration stage, the virtual moment of inertia H is reduced to quickly restore the frequency to a stable value, and the virtual damping coefficient D is simultaneously reduced to reduce the dynamic adjustment time of the new energy grid-connected converter VSG control system, so that the frequency adjustment of the new energy grid-connected converter VSG tends to be stable faster.

[0102] Step S405 The present invention introduces the frequency change rate to characterize the virtual inertia. The new adaptive virtual inertia can be expressed as:

[0103]

[0104] Where: H 0 k is the initial value of the virtual inertia of the new energy grid-connected converter VSG, corresponding to the rated virtual inertia when not participating in frequency regulation; i is the virtual inertia adjustment coefficient.

[0105] Step S5, substituting the new adaptive virtual inertia into the virtual rotor motion equation of the new energy grid-connected converter VSG to obtain the frequency rotation inertia control equation of the high-proportion new energy grid.

[0106] Frequency moment of inertia control equation for high proportion of renewable energy grid; the specific formula is as follows:

[0107]

[0108] In the formula, H i is a new adaptive virtual inertia, D i is the adaptive virtual damping.

[0109] 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 coordinated control can effectively reduce the oscillation frequency during VSG frequency adjustment of the new energy grid-connected converter and maintain the stability of VSG frequency regulation.

[0110] Embodiment 2:

[0111] This embodiment provides a frequency moment of inertia control system for a high-proportion new energy power grid, including:

[0112] Module M1 is used to establish a virtual rotor motion equation for a new energy grid-connected converter VSG to control the active power in the virtual rotor motion equation for the new energy grid-connected converter VSG to control the frequency droop, and obtain an active power-frequency droop equation;

[0113] Module M2, brings the active power-frequency droop equation into the virtual rotor motion equation of the new energy grid-connected converter VSG control, and obtains the new energy grid-connected converter VSG virtual speed regulator control model; at the same time, obtains the new energy grid-connected converter output reactive power regulation equation;

[0114] Module M3, based on the VSG grid-connected equivalent circuit adopted by the new energy grid-connected converter, establishes 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, 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 in stable operation;

[0115] Module M4 uses energy composition function to analyze the transient energy change process of the VSG frequency of the new energy grid-connected converter during frequency adjustment; according to the relationship between the current angular frequency and the initial angular frequency, the frequency adjustment change rate of the VSG frequency of the new energy grid-connected converter during the acceleration and deceleration stages of the virtual angular frequency is analyzed, and the frequency change rate is introduced to characterize the virtual inertia to obtain a new adaptive virtual inertia;

[0116] Module M5 is used to substitute the new adaptive virtual inertia into the virtual rotor motion equation of the new energy grid-connected converter VSG to obtain the frequency rotation inertia control equation of the high-proportion new energy grid.

[0117] Embodiment three:

[0118] This embodiment provides an electronic device having a computer program stored thereon, and when the computer program is executed by a processor, a frequency rotation inertia control method for a high-proportion new energy power grid as described in any embodiment of the present invention is implemented.

[0119] Embodiment 4:

[0120] This embodiment provides a computer-readable medium for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement a frequency rotation inertia control method for a high-proportion new energy power grid as described in any embodiment of the present invention.

[0121] In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated 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 single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0122] Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0123] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0124] In several embodiments provided in the present application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory; hereinafter referred to as: ROM), random access memory (Random Access Memory; hereinafter referred to as: RAM), disk or optical disk, and other media that can store program codes.

[0125] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A frequency moment of inertia control method for a high proportion of new energy power grid, characterized in that: The following steps are involved: Step S1, establishing a virtual rotor motion equation for controlling a new energy grid-connected converter VSG; performing frequency droop control on the active power in the virtual rotor motion equation for controlling a new energy grid-connected converter VSG to obtain an active power-frequency droop equation; Step S2, bringing the active power-frequency droop equation into the virtual rotor motion equation of the new energy grid-connected converter VSG control to obtain the new energy grid-connected converter VSG virtual speed regulator control model; and at the same time, obtaining the new energy grid-connected converter output reactive power regulation equation; Step S3, according to the VSG grid-connected equivalent circuit adopted by 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 in stable operation; Step S4, using the energy composition function to analyze the transient energy change process of the new energy grid-connected converter VSG when the frequency is adjusted; according to the relationship between the current angular frequency and the initial angular frequency, analyzing the frequency adjustment change rate of the new energy grid-connected converter VSG in the acceleration and deceleration stages of the virtual angular frequency, introducing the frequency change rate to characterize the virtual inertia, and obtaining a new adaptive virtual inertia; Step S5, substituting the new adaptive virtual inertia into the virtual rotor motion equation of the new energy grid-connected converter VSG to obtain the frequency rotation inertia control equation of the high-proportion new energy grid.

2. A frequency moment of inertia control method for a high-proportion new energy power grid according to claim 1, characterized in that: The virtual rotor motion equation of the new energy grid-connected converter VSG is established, and the virtual rotor motion equation of the new energy grid-connected converter VSG is expressed as: Where: H is the virtual inertia of VSG; D is the virtual damping of VSG; δ is the virtual power angular velocity of VSG; ω is the virtual electrical angular velocity; ω0 is the synchronous angular velocity of the grid-connected converter of the new energy grid; P m Output virtual mechanical power for VSG; P e It is the actual output value of active power of the new energy grid-connected converter system.

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

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

5. The method for controlling frequency moment of inertia of a high-proportion renewable energy grid according to claim 1, characterized in that: The output power of the VSG is obtained when the VSG control system of the new energy grid-connected converter is in stable operation. The output power of the VSG is expressed as: Where: e d 、e q They are the d-axis and q-axis voltage components of the VSG control system of the new energy grid-connected converter; i d 、i q are the d-axis and q-axis output currents respectively; X is the equivalent inductive reactance; δ is the VSG virtual power angular velocity.

6. A method for controlling frequency moment of inertia of a high-proportion renewable energy grid according to claim 1, characterized in that: The energy composition function is used to analyze the transient energy change process when the VSG frequency of the new energy grid-connected converter is adjusted, wherein the specific formula of the energy composition function is as follows: Where: W x , W s , W d is the energy required for kinetic energy, potential energy and damping of the new energy grid-connected converter VSG; δ0 is the initial virtual power angle of the new energy grid-connected converter VSG; P δ is the output power of the new energy grid-connected converter VSG when the virtual power angle is δ; When the virtual power angle is the initial power angle, the new energy grid-connected converter VSG output power.

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

8. A frequency inertia control system for a high-proportion renewable energy grid, characterized in that: include: Module M1 is used to establish the virtual rotor motion equation of the new energy grid-connected converter VSG control; The frequency droop control is performed on the active power in the virtual rotor motion equation of the new energy grid-connected converter VSG to obtain the active power-frequency droop equation; Module M2, brings the active power-frequency droop equation into the virtual rotor motion equation of the new energy grid-connected converter VSG control, and obtains the new energy grid-connected converter VSG virtual speed regulator control model; at the same time, obtains the new energy grid-connected converter output reactive power regulation equation; Module M3, based on the VSG grid-connected equivalent circuit adopted by the new energy grid-connected converter, establishes 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, 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 in stable operation; Module M4 uses energy composition function to analyze the transient energy change process of the VSG frequency of the new energy grid-connected converter during frequency adjustment; according to the relationship between the current angular frequency and the initial angular frequency, the frequency adjustment change rate of the VSG frequency of the new energy grid-connected converter during the acceleration and deceleration stages of the virtual angular frequency is analyzed, and the frequency change rate is introduced to characterize the virtual inertia to obtain a new adaptive virtual inertia; Module M5 is used to substitute the new adaptive virtual inertia into the virtual rotor motion equation of the new energy grid-connected converter VSG to obtain the frequency rotation 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, a frequency rotation inertia control method for a high-proportion new energy power grid is implemented 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 a processor, a frequency rotation inertia control method for a high-proportion new energy power grid is implemented as described in any one of claims 1 to 7.

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