Dynamic stability control method applicable to new energy power system, and system

Abstract

Disclosed in the present invention are a dynamic stability control method applicable to a new energy power system, and a system. The method comprises: creating a grid-forming inverter nonlinear system corresponding to a new energy power system, and, on the basis of Lie derivatives, establishing an external subsystem corresponding to the grid-forming inverter; on the basis of the external subsystem, constructing a corresponding linear sliding mode surface, and, on the basis of a sliding mode control method, generating a corresponding dynamic stability control unit; and generating and acquiring first instruction data corresponding to the dynamic stability control unit, and, on the basis of the first instruction data, controlling the dynamic stability of the new energy power system in real time. Thus, by means of modifying the voltage instruction value of the inverter, the dynamic stability of the system is improved. Thus, the solution of the present invention establishes the external subsystem of the new energy power system, and, on the basis of the sliding mode control method, derives an analytical expression for a voltage control signal of the inverter, thereby improving the dynamic stability of the system by means of modifying the voltage instruction value of the inverter.

Description

A dynamic stability control method and system applicable to new energy power systems Technical Field

[0001] This invention belongs to the field of new energy power system technology, specifically relating to a dynamic stability control method and system suitable for new energy power systems. Background Technology

[0002] With the increasing frequency of extreme weather events globally in recent years, countries are facing a growing need to reduce their use of fossil fuels and carbon emissions. Increasing the proportion of renewable energy in primary energy consumption is a crucial pathway to achieving carbon peaking and carbon neutrality. Renewable energy sources, such as solar and wind power, are typically connected to the grid via inverters. As the proportion of renewable energy increases, traditional power systems dominated by synchronous machines will evolve into inverter-dominated power systems. Achieving zero carbon emissions, a 100% renewable energy power system is the ultimate goal of power system development and has received widespread attention from scholars in recent years. Under current planning and operational levels, achieving energy balance in a 100% renewable energy power system has become possible. However, a 100% renewable energy power system will lose the support of synchronous machines and become a fully inverter-driven, electronically-based power system. The integration of inverters presents a significant challenge to the dynamic stability of a 100% renewable energy power system.

[0003] In power systems dominated by synchronous machines, dynamic stability is ensured by power system stabilizers. The basic idea behind power system stabilizer design is to add a small signal to the voltage reference value of the excitation system, thereby providing damping torque to the synchronous machine at its oscillation frequency. This approach improves the dynamic stability of the power system with almost no negative impact and is widely adopted in synchronous machine-dominated power systems. However, the structure of the power system stabilizer is determined based on the analysis results of the Hayfjer-Phillips model of the synchronous machine. Due to the significant differences in the operating characteristics of inverters and synchronous machines, the power system stabilizer structure for synchronous machines is not entirely applicable to inverters.

[0004] Therefore, in order to address the above-mentioned technical problems and deficiencies, there is an urgent need to design and develop a dynamic stability control method and system suitable for new energy power systems.

[0005] Summary of the Invention

[0006] To overcome the shortcomings and difficulties of the existing technology, the purpose of this invention is to provide a dynamic stability control method and system suitable for new energy power systems, so as to improve the dynamic stability of the system by modifying the voltage command value of the inverter.

[0007] The first objective of this invention is to provide a dynamic stability control method suitable for new energy power systems; the second objective of this invention is to provide a dynamic stability control system suitable for new energy power systems.

[0008] The first objective of this invention is achieved as follows: the method comprises the following steps:

[0009] A nonlinear system for a grid-type inverter corresponding to a new energy power system is created, and an external subsystem corresponding to the grid-type inverter is established based on Lie derivatives.

[0010] Based on the external subsystem, a corresponding linear sliding surface is constructed, and a corresponding dynamic stability control unit is generated based on the sliding mode control method;

[0011] Generate and acquire first instruction data corresponding to the dynamic stability control unit, and control the dynamic stability of the new energy power system in real time according to the first instruction data; wherein, the first instruction data is voltage instruction value data.

[0012] Furthermore, the creation of a nonlinear system for a grid-connected inverter corresponding to a new energy power system, and the establishment of an external subsystem corresponding to the grid-connected inverter based on the Lie derivative, further includes:

[0013] Create at least three control loops corresponding to the nonlinear system of the grid-type inverter; wherein the control loops include a virtual synchronization loop, an inner current loop, and an outer current loop;

[0014] Based on the control loop, corresponding inner loop current controller models and outer loop current controller models are constructed respectively.

[0015] Select and obtain the voltage reference value data and power angle deviation data corresponding to the target inverter, and establish a nonlinear SISO model corresponding to the inverter.

[0016] Furthermore, the creation of a nonlinear system for a grid-connected inverter corresponding to a new energy power system, and the establishment of an external subsystem corresponding to the grid-connected inverter based on the Lie derivative, further includes:

[0017] A positive-sequence fundamental frequency model corresponding to the nonlinear system of the grid-type inverter is established; the expression of the positive-sequence fundamental frequency model is as follows:

[0018] Among them, v d and v q These are the outputs of the inner loop controller's dq axes, R arm and L arm These are the bridge arm resistance and inductance, respectively, and ω is the inverter frequency.

[0019] Furthermore, in establishing the nonlinear SISO model corresponding to the inverter, the specific expression of the nonlinear SISO model is as follows:

[0020] Where: Δω and Δδ are the inverter's speed and power angle deviation, respectively, i sd and i sq These are the d-axis and q-axis components of the inverter output current, respectively. id and M iq M represents the state variables of the integral element of the inner loop current controller for the dq axis, respectively. Us and M uq These are the state variables of the integral element of the outer loop controller for the dq axis, where ω0 is the reference frequency and H is the integrator. m and D m These are the rotor inertia time constant and damping coefficient, ΔP, respectively. s R is the change in power. arm and L arm These are the bridge arm resistors and inductors, k pid and k iid These represent the proportional and integral coefficients of the d-axis inner loop current controller, respectively, and k piq and k iiq These represent the proportional and integral coefficients of the q-axis inner loop current controller, respectively, where u is the input signal, U sref k is the reference value for the inverter output voltage. pUs and k iUs These are the proportional and integral coefficients of the inverter's d-axis outer loop controller, respectively, k puq and k iuq These are the proportional and integral coefficients of the inverter's q-axis outer loop controller, u sd and u sq dq axis components of the IBG output voltage, and y is the system output variable.

[0021] Furthermore, the step of constructing a corresponding linear sliding surface based on the external subsystem and generating a corresponding dynamic stability control unit based on the sliding mode control method further includes:

[0022] Based on the linear sliding surface, a hybrid convergence law corresponding to the linear sliding surface is generated;

[0023] Based on the hybrid approach law, inverter input signal data corresponding to the nonlinear system of the grid-type inverter is generated.

[0024] Furthermore, after generating and acquiring the first instruction data corresponding to the dynamic stability control unit, and controlling the dynamic stability of the new energy power system in real time according to the first instruction data, the method further includes:

[0025] The system generates and acquires fault data corresponding to the new energy power system, and verifies the dynamic stability of the new energy power system in real time based on the fault data.

[0026] The second objective of this invention is achieved as follows: the system is applied to the dynamic stability control method, and the system comprises:

[0027] The first system creation unit is used to create a nonlinear system for a grid-type inverter corresponding to a new energy power system, and to establish an external subsystem corresponding to the grid-type inverter based on Lie derivatives.

[0028] The data construction and generation unit is used to construct a corresponding linear sliding surface based on the external subsystem, and generate a corresponding dynamic stability control unit based on the sliding mode control method.

[0029] The first data generation unit is used to generate and acquire first instruction data corresponding to the dynamic stability control unit, and to control the dynamic stability of the new energy power system in real time according to the first instruction data; wherein, the first instruction data is voltage instruction value data.

[0030] Furthermore, the first system creation unit also includes:

[0031] The first building module is used to create at least three control loops corresponding to the nonlinear system of the grid-type inverter; wherein the control loops include a virtual synchronization loop, an inner current loop, and an outer current loop;

[0032] The second construction module is used to construct corresponding inner loop current controller models and outer loop current controller models based on the control loop.

[0033] The third construction module is used to select and acquire voltage reference value data and power angle deviation data corresponding to the target inverter, and to establish a nonlinear SISO model corresponding to the inverter.

[0034] And / or, the data construction and generation unit further includes:

[0035] The first generation module is used to generate a hybrid convergence law corresponding to the linear sliding surface based on the linear sliding surface;

[0036] The second generation module is used to generate inverter input signal data corresponding to the nonlinear system of the grid-type inverter according to the hybrid approach law;

[0037] And / or, the system further includes:

[0038] A generation and verification module is used to generate and acquire fault data corresponding to the new energy power system, and to verify the dynamic stability of the new energy power system in real time based on the fault data.

[0039] Furthermore, the first system creation unit also includes:

[0040] The fourth construction module is used to establish a positive-sequence fundamental frequency model corresponding to the nonlinear system of the grid-type inverter; the expression of the positive-sequence fundamental frequency model is as follows:

[0041] Among them, v d and v q These are the outputs of the inner loop controller's dq axes, R arm and L arm These are the bridge arm resistance and inductance, respectively, and ω is the inverter frequency.

[0042] Furthermore, in the third building module, the specific expression of the nonlinear SISO model corresponding to the inverter is as follows:

[0043] Where: Δω and Δδ are the inverter's speed and power angle deviation, respectively, i sd and i sq These are the d-axis and q-axis components of the inverter output current, respectively. id and M iq M represents the state variables of the integral element of the inner loop current controller for the dq axis, respectively. Us and M uq These are the state variables of the integral element of the outer loop controller for the dq axis, where ω0 is the reference frequency and H is the integrator. m and D m These are the rotor inertia time constant and damping coefficient, ΔP, respectively. s R is the change in power. arm and L arm These are the bridge arm resistors and inductors, k pid and k iid These represent the proportional and integral coefficients of the d-axis inner loop current controller, respectively, and k piq and k iiq These represent the proportional and integral coefficients of the q-axis inner loop current controller, respectively, where u is the input signal, U sref k is the reference value for the inverter output voltage. pUs and k iUs These are the proportional and integral coefficients of the inverter's d-axis outer loop controller, respectively, k puq and k iuq These are the proportional and integral coefficients of the inverter's q-axis outer loop controller, u sd and u sqdq axis components of the IBG output voltage, and y is the system output variable.

[0044] This invention creates a nonlinear system for a grid-connected inverter corresponding to a new energy power system through a method, and establishes an external subsystem corresponding to the grid-connected inverter based on Lie derivatives; constructs a corresponding linear sliding mode surface based on the external subsystem, and generates a corresponding dynamic stability control unit based on a sliding mode control method; generates and acquires first command data corresponding to the dynamic stability control unit, and controls the dynamic stability of the new energy power system in real time based on the first command data; wherein the first command data is voltage command value data; and a system corresponding to the method, which improves the dynamic stability of the system by modifying the voltage command value of the inverter.

[0045] In other words, the present invention constructs an external subsystem of a new energy power system and derives an analytical expression for the inverter voltage control signal based on the sliding mode control method, thereby improving the dynamic stability of the system by modifying the inverter voltage command value. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 is a schematic diagram of an inverter model for a dynamic stability control method applicable to new energy power systems.

[0048] Figure 2 is a schematic diagram of an 11-node system with 100% new energy penetration, which is a dynamic stability control method applicable to new energy power systems according to the present invention.

[0049] Figure 3 is a schematic diagram of the oscillation phenomenon of the system before applying the dynamic stability control method of the present invention, which is applicable to the dynamic stability control method of new energy power system.

[0050] Figure 4 is a schematic diagram of the stability result of the system after applying the dynamic stability control method of the present invention, which is applicable to the dynamic stability control method of new energy power system.

[0051] Figure 5 is a schematic flowchart of a dynamic stability control method applicable to new energy power systems according to the present invention.

[0052] Figure 6 is a schematic diagram of a dynamic stability control system architecture applicable to new energy power systems according to the present invention.

[0053] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0054] To facilitate a clearer understanding of the objectives, technical solutions, and advantages of this invention, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Those skilled in the art can easily understand other advantages and effects of this invention from the content disclosed in this specification.

[0055] This invention can also be implemented or applied through other different specific examples, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of this invention.

[0056] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0057] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Secondly, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0058] The present invention will be further described in detail below with reference to the accompanying drawings. As shown in Figures 1-5, the present invention provides a dynamic stability control method suitable for new energy power systems. The method includes the following steps:

[0059] S1. Create a nonlinear system for a grid-type inverter corresponding to the new energy power system, and establish an external subsystem corresponding to the grid-type inverter based on Lie derivatives;

[0060] S2. Based on the external subsystem, construct the corresponding linear sliding surface and generate the corresponding dynamic stability control unit based on the sliding mode control method;

[0061] S3. Generate and acquire first instruction data corresponding to the dynamic stability control unit, and control the dynamic stability of the new energy power system in real time according to the first instruction data; wherein, the first instruction data is voltage instruction value data.

[0062] The creation of a nonlinear system for a grid-connected inverter corresponding to a new energy power system, and the establishment of an external subsystem corresponding to the grid-connected inverter based on Lie derivatives, further includes:

[0063] S11. Create at least three control loops corresponding to the nonlinear system of the grid-type inverter; wherein, the control loop includes a virtual synchronization loop, an inner current loop, and an outer current loop;

[0064] S12. Based on the control loop, construct the corresponding inner loop current controller model and outer loop current controller model respectively;

[0065] S13. Select and obtain the voltage reference value data and power angle deviation data corresponding to the target inverter respectively, and establish the nonlinear SISO model corresponding to the inverter.

[0066] The creation of a nonlinear system for a grid-connected inverter corresponding to a new energy power system, and the establishment of an external subsystem corresponding to the grid-connected inverter based on Lie derivatives, further includes:

[0067] S14. Establish a positive-sequence fundamental frequency model corresponding to the nonlinear system of the grid-type inverter; the expression of the positive-sequence fundamental frequency model is as follows:

[0068] Among them, v d and v q These are the outputs of the inner loop controller's dq axes, R arm and L arm These are the bridge arm resistance and inductance, respectively, and ω is the inverter frequency.

[0069] In establishing the nonlinear SISO model corresponding to the inverter, the specific expression of the nonlinear SISO model is as follows:

[0070] Where: Δω and Δδ are the inverter's speed and power angle deviation, respectively, i sd and i sq These are the d-axis and q-axis components of the inverter output current, respectively. id and M iq M represents the state variables of the integral element of the inner loop current controller for the dq axis, respectively. Us and M uq These are the state variables of the integral element of the outer loop controller for the dq axis, where ω0 is the reference frequency and H is the integrator. m and Dm These are the rotor inertia time constant and damping coefficient, ΔP, respectively. s R is the change in power. arm and L arm These are the bridge arm resistors and inductors, k pid and k iid These represent the proportional and integral coefficients of the d-axis inner loop current controller, respectively, and k piq and k iiq These represent the proportional and integral coefficients of the q-axis inner loop current controller, respectively, where u is the input signal, U sref k is the reference value for the inverter output voltage. pUs and k iUs These are the proportional and integral coefficients of the inverter's d-axis outer loop controller, respectively, k puq and k iuq These are the proportional and integral coefficients of the inverter's q-axis outer loop controller, u sd and u sq dq axis components of the IBG output voltage, and y is the system output variable.

[0071] The step of constructing a corresponding linear sliding surface based on the external subsystem and generating a corresponding dynamic stability control unit based on the sliding mode control method further includes:

[0072] S21. Based on the linear sliding surface, generate a hybrid approach law corresponding to the linear sliding surface;

[0073] S22. Based on the hybrid approach law, generate inverter input signal data corresponding to the nonlinear system of the grid-type inverter.

[0074] After generating and acquiring the first instruction data corresponding to the dynamic stability control unit, and controlling the dynamic stability of the new energy power system in real time according to the first instruction data, the method further includes:

[0075] S40. Generate and acquire fault data corresponding to the new energy power system, and verify the dynamic stability of the new energy power system in real time based on the fault data.

[0076] Specifically, in this embodiment of the invention, a dynamic stability control method for a 100% new energy power system is provided. First, the external subsystem model of the inverter is obtained by linearizing the input and output, and the expression of the external subsystem is derived using Lie derivatives. Then, a hybrid reaching law of sliding mode surface is proposed, and the dynamic stability controller of the inverter is designed based on the reaching law.

[0077] The steps include: (1) Deriving the standard form of the nonlinear system of the grid-type inverter. (2) Deriving the expression of the external subsystem of the grid-type inverter using Lie derivatives. (3) Proposing the hybrid approach law of the sliding surface. (4) Obtaining the dynamic stability controller of the inverter based on the sliding mode control method.

[0078] In step (1), the standard form of the nonlinear system of the grid-type inverter is obtained through the following formula:

[0079] Where: Δω and Δδ are the inverter's speed and power angle deviation, respectively, i sd and i sq These are the d-axis and q-axis components of the inverter output current, respectively. id and M iq M represents the state variables of the integral element of the inner loop current controller for the dq axis, respectively. Us and M uq These are the state variables of the integral element of the outer loop controller for the dq axis, where ω0 is the reference frequency and H is the integrator. m and D m These are the rotor inertia time constant and damping coefficient, ΔP, respectively. s R is the change in power. arm and L arm These are the bridge arm resistors and inductors, k pid and k iid These represent the proportional and integral coefficients of the d-axis inner loop current controller, respectively, and k piq and k iiq These represent the proportional and integral coefficients of the q-axis inner loop current controller, respectively, where u is the input signal, U sref k is the reference value for the inverter output voltage. pUs and k iUs These are the proportional and integral coefficients of the inverter's d-axis outer loop controller, respectively, k puq and k iuq These are the proportional and integral coefficients of the inverter's q-axis outer loop controller, u sd and u sq dq axis components of the IBG output voltage, and y is the system output variable.

[0080] In step (2), the expression for the external subsystem of the grid-type inverter is obtained through the following formula:

[0081] Where: ζ i Let L3 fy represent the external subsystem variable, and let L3 fy be the third Lie derivative of the output variable y with respect to the system function f. g L2 fy is the third Lie derivative of the output variable y with respect to the input function g.

[0082] In step (3), the mixing convergence law of the sliding surface is proposed by the following formula.

[0083] Where λ1 and λ2 are constant coefficients, v is the sliding mode surface, α>1, 0<β<1, k and ε are constant coefficients, sat() is the saturation function, and Γ is the boundary layer height and thickness, 0<Γ<1. When |ν|>Γ, the power term ensures that the system state approaches the sliding mode at a relatively fast rate. When |ν|<Γ, the saturation function uses linear feedback control within the boundary layer to achieve a smooth transition and reduce system chattering.

[0084] In step (4), the dynamic stability controller of the inverter is obtained by the following formula.

[0085] In other words, the present invention provides a dynamic stability control method suitable for new energy power systems, as detailed below:

[0086] (1) Derive the standard form of the nonlinear system of the grid-type inverter;

[0087] The structure of a grid-connected inverter model is shown in Figure 1. The inverter controller includes three control loops: a virtual synchronization loop, an inner current loop, and an outer current loop. In Figure 1, P... s and P sref U represents the actual and reference values ​​of the inverter's output active power, respectively. s and U sref These represent the actual and reference values ​​of the inverter bus voltage, respectively. sq The q-axis component represents the bus voltage.

[0088] The positive-sequence fundamental frequency model of the inverter body can be established as follows:

[0089] In the formula, v d and v q These are the outputs of the inner loop controller's dq axes, R arm and L arm These are the bridge arm resistance and inductance, respectively, and ω is the inverter frequency, which can be approximated as the base frequency.

[0090] Ignoring the modulation stage, the inner-loop current controller model of the inverter is as follows:

[0091] In the formula, M id and M iq Let k represent the state variables of the integral element of the inner loop current controller for the dq-axis, respectively. pid and k iid These represent the proportional and integral coefficients of the d-axis inner loop current controller, respectively, and k piq and kiiq i represents the proportional and integral coefficients of the q-axis inner loop current controller, respectively. sdref and i sqref These represent the reference values ​​for the dq axis current, respectively.

[0092] The outer loop current controller model of the inverter is as follows:

[0093] In the formula, U sref k is the reference value for the inverter output voltage. pUs and k iUs These are the proportional and integral coefficients of the inverter's d-axis outer loop controller, respectively, k puq and k iuq These are the proportional and integral coefficients of the inverter's q-axis outer loop controller, respectively. Us and M uq These are the state variables of the integral element of the outer loop controller for the dq axis, respectively.

[0094] Select the voltage reference value U of the target inverter. sref Using the inverter's power angle deviation Δδ as input and the inverter's output, a nonlinear SISO model of the inverter is established:

[0095] (2) Derive the expression of the external subsystem of the grid-type inverter using Lie derivative.

[0096] Write the output variable y in the form of Lie derivative:

[0097] Because of L g Since y = 0, we continue to find the second Lie derivative of y:

[0098] L can be obtained g L f Since y is still 0, continue to find the third Lie derivative of y:

[0099] At this time, L g L2 fy is no longer 0, therefore the third-order linear external subsystem of the original system can be obtained using the input-output linearization method:

[0100] in,

[0101] The expressions for each item are as follows:

[0102] The expression for L2 fy is:

[0103] (3) The mixing convergence law of sliding surfaces is proposed.

[0104] For a third-order external subsystem, a linear sliding surface is selected: ν=λ1ζ1+λ2ζ2+ζ3 (23)

[0105] In the formula, λ1 and λ2 are constant coefficients.

[0106] After the system trajectory approaches the sliding surface, ζ1 tends towards zero motion, where ν = 0 on the sliding surface. Therefore, when ζ1 moves on the sliding surface, it satisfies:

[0107] The natural frequency and damping coefficient of the ζ1 motion are as follows:

[0108] In the formula, ω n Let ζ1 be the natural frequency as it moves on the sliding surface. Let λ1 be the damping ratio when ζ1 moves on the sliding surface. λ1 and λ2 can be tuned by selecting the natural frequency and damping coefficient.

[0109] The derivative of ν satisfies:

[0110] To ensure that the system trajectory reaches the sliding surface more quickly and that the motion near the sliding surface is smooth, a new hybrid reaching law is proposed:

[0111] In the formula, α, β, k and ε are constant coefficients, α>1, 0<β<1.

[0112] sat() is a saturation function, and its expression is:

[0113] Where Γ is the boundary layer height and thickness, 0 < Γ < 1. When |ν| > Γ, the power term can ensure that the system state approaches the sliding mode at a relatively fast speed. When |ν| < Γ, the saturation function adopts linear feedback control within the boundary layer to achieve a smooth transition and reduce system chattering.

[0114] (4) The dynamic stability controller of the inverter is obtained based on the sliding mode control method.

[0115] Based on the derivative of the sliding surface and the mixing tendency law, we should have:

[0116] Therefore, the input signal of the inverter based on sliding mode control is:

[0117] (5) Verification by example

[0118] The verification was conducted in a modified IEEE 11-node system. In this system, the original four synchronous generators were replaced by inverters while maintaining the original output, and the length of the interconnection line between the two zones was doubled. The topology of the modified IEEE 11-node system is shown in Figure 2. Before applying the dynamic stability control method, a small disturbance was applied, and the response curves of each inverter are shown in Figure 3. As can be seen from Figure 3, the units in the system oscillate and are dynamically unstable. After applying the dynamic stability control method, the same fault was applied, and the response curves of each inverter are shown in Figure 4. Comparing Figures 3 and 4, it can be seen that the dynamic stability control method can effectively improve the dynamic stability of a 100% renewable energy power system.

[0119] To achieve the above objectives, the present invention also provides a dynamic stability control system suitable for new energy power systems, as shown in Figure 6.

[0120] The system is applied to the dynamic stability control method, and the system includes:

[0121] The first system creation unit is used to create a nonlinear system for a grid-type inverter corresponding to a new energy power system, and to establish an external subsystem corresponding to the grid-type inverter based on Lie derivatives.

[0122] The data construction and generation unit is used to construct a corresponding linear sliding surface based on the external subsystem, and generate a corresponding dynamic stability control unit based on the sliding mode control method.

[0123] The first data generation unit is used to generate and acquire first instruction data corresponding to the dynamic stability control unit, and to control the dynamic stability of the new energy power system in real time according to the first instruction data; wherein, the first instruction data is voltage instruction value data.

[0124] Furthermore, the first system creation unit also includes:

[0125] The first building module is used to create at least three control loops corresponding to the nonlinear system of the grid-type inverter; wherein the control loops include a virtual synchronization loop, an inner current loop, and an outer current loop;

[0126] The second construction module is used to construct corresponding inner loop current controller models and outer loop current controller models based on the control loop.

[0127] The third construction module is used to select and acquire voltage reference value data and power angle deviation data corresponding to the target inverter, and to establish a nonlinear SISO model corresponding to the inverter.

[0128] And / or, the data construction and generation unit further includes:

[0129] The first generation module is used to generate a hybrid convergence law corresponding to the linear sliding surface based on the linear sliding surface;

[0130] The second generation module is used to generate inverter input signal data corresponding to the nonlinear system of the grid-type inverter according to the hybrid approach law;

[0131] And / or, the system further includes:

[0132] A generation and verification module is used to generate and acquire fault data corresponding to the new energy power system, and to verify the dynamic stability of the new energy power system in real time based on the fault data.

[0133] The first system creation unit further includes:

[0134] The fourth construction module is used to establish a positive-sequence fundamental frequency model corresponding to the nonlinear system of the grid-type inverter; the expression of the positive-sequence fundamental frequency model is as follows:

[0135] Among them, v d and v q These are the outputs of the inner loop controller's dq axes, R arm and L arm These are the bridge arm resistance and inductance, respectively, and ω is the inverter frequency.

[0136] In the third construction module, the specific expression of the nonlinear SISO model corresponding to the inverter is as follows:

[0137] Where: Δω and Δδ are the inverter's speed and power angle deviation, respectively, i sd and i sq These are the d-axis and q-axis components of the inverter output current, respectively. id and M iq M represents the state variables of the integral element of the inner loop current controller for the dq axis, respectively. Us and M uq These are the state variables of the integral element of the outer loop controller for the dq axis, where ω0 is the reference frequency and H is the integrator. m and D m These are the rotor inertia time constant and damping coefficient, ΔP, respectively. s R is the change in power.arm and L arm These are the bridge arm resistors and inductors, k pid and k iid These represent the proportional and integral coefficients of the d-axis inner loop current controller, respectively, and k piq and k iiq These represent the proportional and integral coefficients of the q-axis inner loop current controller, respectively, where u is the input signal, U sref k is the reference value for the inverter output voltage. pUs and k iUs These are the proportional and integral coefficients of the inverter's d-axis outer loop controller, respectively, k puq and k iuq These are the proportional and integral coefficients of the inverter's q-axis outer loop controller, u sd and u sq dq axis components of the IBG output voltage, and y is the system output variable.

[0138] In the system solution embodiment of the present invention, the specific details of the method steps involved in the dynamic stability control of the new energy power system have been described above. That is to say, the functional modules in the system are used to implement the steps or sub-steps in the above method embodiment, which will not be repeated here.

[0139] This invention creates a nonlinear system for a grid-connected inverter corresponding to a new energy power system through a method, and establishes an external subsystem corresponding to the grid-connected inverter based on Lie derivatives; constructs a corresponding linear sliding mode surface based on the external subsystem, and generates a corresponding dynamic stability control unit based on a sliding mode control method; generates and acquires first command data corresponding to the dynamic stability control unit, and controls the dynamic stability of the new energy power system in real time based on the first command data; wherein, the first command data is voltage command value data; to improve the dynamic stability of the system by modifying the voltage command value of the inverter.

[0140] In other words, this invention constructs an external subsystem for a renewable energy power system and derives an analytical expression for the inverter voltage control signal based on the sliding mode control method. This allows for the improvement of the system's dynamic stability by modifying the inverter's voltage command value. In other words, this invention addresses the dynamic stability problem of a 100% renewable energy power system, proposing a dynamic stability control method for such systems. The calculated results effectively improve the dynamic stability of the 100% renewable energy power system during operation, promoting its realization and ensuring its safe and stable operation.

[0141] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A dynamic stability control method suitable for a new energy power system, characterized in that, The method comprises the steps of: creating a grid-connected inverter nonlinear system corresponding to a new energy power system, and establishing an external subsystem corresponding to the grid-connected inverter based on Lie derivative; according to the external subsystem, constructing a corresponding linear sliding surface, and generating a corresponding dynamic stability control unit based on a sliding mode control method; generating and obtaining first instruction data corresponding to the dynamic stability control unit, and controlling the dynamic stability of the new energy power system in real time according to the first instruction data; wherein the first instruction data is voltage instruction value data.

2. The dynamic stability control method for a new energy power system according to claim 1, characterized in that, The creation of a grid-connected inverter nonlinear system corresponding to a new energy power system, and the establishment of an external subsystem corresponding to the grid-connected inverter based on Lie derivative, further comprises: creating at least three control loops corresponding to the grid-connected inverter nonlinear system; wherein the control loops include a virtual synchronous loop, an inner current loop and an outer current loop; based on the control loops, constructing a corresponding inner loop current controller model and an outer loop current controller model, respectively; selecting and obtaining voltage reference value data and power angle deviation data corresponding to the target inverter, respectively, and establishing a nonlinear SISO model corresponding to the inverter.

3. The dynamic stability control method for a new energy power system according to claim 1 or 2, characterized in that, The creation of a grid-connected inverter nonlinear system corresponding to a new energy power system, and the establishment of an external subsystem corresponding to the grid-connected inverter based on Lie derivative, further comprises: A positive sequence fundamental frequency model corresponding to the networked inverter nonlinear system is established; the expression of the positive sequence fundamental frequency model is specifically as follows: where v d and v q are the outputs of the inner-loop controller on the dq-axes, R arm and L arm are the resistance and inductance of the bridge arm, and ω is the inverter frequency.

4. The dynamic stability control method for a new energy power system according to claim 2, characterized in that, In the establishing of the nonlinear SISO model corresponding to the inverter, the nonlinear SISO model expression is specifically as follows: where Δω and Δδ are the speed and power angle deviation of the inverter, respectively, i sd and i sq are the d-axis and q-axis components of the inverter output current, M id and M iq are the state variables of the dq-axis inner loop current controller integral term, M Us and M uq are the state variables of the dq-axis outer loop controller integral term, ω0 is the reference frequency, H m and D m are the rotor inertia time constant and damping coefficient, respectively, ΔP s is the power variation, R arm and L arm are the bridge arm resistance and inductance, respectively, k pid and k iid are the d-axis inner loop current controller proportional and integral coefficients, respectively, k piq and k iiq are the q-axis inner loop current controller proportional and integral coefficients, respectively, u is the input signal, U sref is the inverter outlet voltage reference value, k pUs and k iUs are the inverter d-axis outer loop controller proportional and integral coefficients, respectively, k puq and k iuq are the inverter q-axis outer loop controller proportional and integral coefficients, respectively, u sd and u sq are the dq-axis components of the IBG outlet voltage, y is the system output variable.

5. The dynamic stability control method for new energy power system according to claim 1, characterized in that, According to the external subsystem, a corresponding linear sliding surface is constructed, and a corresponding dynamic stability control unit is generated based on a sliding mode control method, which further comprises: based on the linear sliding surface, generating a hybrid reaching law corresponding to the linear sliding surface; according to the hybrid reaching law, generating inverter input signal data corresponding to the grid-connected inverter nonlinear system.

6. The dynamic stability control method for new energy power system according to claim 1, characterized in that, After the generation and acquisition of the first instruction data corresponding to the dynamic stability control unit, and the real-time control of the dynamic stability of the new energy power system according to the first instruction data, further comprising: generating and obtaining fault data corresponding to the new energy power system, and based on the fault data, verifying the dynamic stability of the new energy power system in real time.

7. A dynamic stability control system suitable for use in a new energy power system, characterized by, The system is applied to the dynamic stability control method of any one of claims 1-6, and the system comprises: a first system creation unit for creating a grid-connected inverter nonlinear system corresponding to a new energy power system, and establishing an external subsystem corresponding to the grid-connected inverter based on Lie derivative; a data construction generation unit for constructing a corresponding linear sliding surface according to the external subsystem, and generating a corresponding dynamic stability control unit based on a sliding mode control method; a first data generation unit for generating and obtaining first instruction data corresponding to the dynamic stability control unit, and controlling the dynamic stability of the new energy power system in real time according to the first instruction data; wherein the first instruction data is voltage instruction value data.

8. The dynamic stability control system for new energy power system according to claim 7, characterized in that, The first system creation unit further comprises: The first construction module is configured to create at least three control loops corresponding to the grid-connected inverter nonlinear system; wherein the control loops comprise a virtual synchronous loop, an inner current loop and an outer current loop; The second construction module is configured to construct a corresponding inner loop current controller model and an outer loop current controller model based on the control loops; The third construction module is configured to select, respectively, voltage reference value data and power angle deviation data corresponding to a target inverter, and establish a nonlinear SISO model corresponding to the inverter; And / or, the data construction generation unit further comprises: The first generation module is configured to generate a hybrid reaching law corresponding to the linear sliding surface based on the linear sliding surface; The second generation module is configured to generate inverter input signal data corresponding to the grid-connected inverter nonlinear system according to the hybrid reaching law; And / or, the system further comprises: The generation verification module is configured to generate and acquire fault data corresponding to the new energy power system, and verify the dynamic stability of the new energy power system in real time based on the fault data.

9. The dynamic stability control system for new energy power system according to claim 7 or 8, characterized in that, The first system creation unit further comprises: A fourth construction module is configured to establish a positive sequence fundamental frequency model corresponding to the network-type inverter nonlinear system; and the positive sequence fundamental frequency model expression is specifically as follows: where v d and v q are the inner-loop controller dq-axis outputs, R arm and L arm are the bridge-arm resistance and inductance, and ω is the inverter frequency.

10. The dynamic stability control system for new energy power system according to claim 8, characterized in that, In the establishing of the nonlinear SISO model corresponding to the inverter, the nonlinear SISO model expression is specifically as follows: where Δω and Δδ are the speed and power angle deviation of the inverter, respectively, i sd and i sq are the d- and q-axis components of the inverter output current, respectively, M id and M iq are the state variables of the integral term of the dq-axis inner current controller, respectively, M Us and M uq are the state variables of the integral term of the dq-axis inner current controller, respectively, ω0is the reference frequency, H m and D m are the rotor inertia time constant and damping coefficient, respectively, ΔP s is the power variation, R arm and L arm are the bridge arm resistance and inductance, respectively, k pid and k iid are the proportional and integral coefficients of the d-axis inner loop current controller, respectively, k piq and k iiq are the proportional and integral coefficients of the q-axis inner loop current controller, respectively, u is the input signal, U sref is the inverter outlet voltage reference value, k pUs and k iUs are the proportional and integral coefficients of the d-axis outer loop controller of the inverter, respectively, k puq and k iuq are the proportional and integral coefficients of the q-axis outer loop controller of the inverter, respectively, u sd and u sq are the dq-axis components of the IBG outlet voltage, y is the system output variable.

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