Passive control-based frequency control method and system for network construction type converter

Abstract

The invention discloses a passive control-based frequency control method and system for a network construction type converter, and the method comprises the steps: converting a virtual synchronous control equation into a Hamiltonian equation form, and generating a Hamiltonian system energy function based on a coefficient of a Hamiltonian equation standard form; verifying whether the virtual synchronous control system meets passivity or not based on a dissipation inequality of a passivity theory; when it is judged that the virtual synchronous control system meets passivity verification, a Hamiltonian energy function is injected into the virtual synchronous control system, and a passive control law is determined based on an expected balance point of the virtual synchronous control system; and on the basis of the passive control law, controlling the frequency of the passively-controlled network-constructing type converter. According to the technical scheme, on-site actual measurement of frequency control of the grid-connected system of the grid-forming type converter is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, and more particularly to a grid-forming converter frequency control method and system based on passive control. BACKGROUND

[0002] Under the double carbon target, new energy power generation represented by wind power develops rapidly, and the installed capacity continues to increase, which leads to insufficient system inertia and decreased frequency modulation capability, seriously threatening the safety of the power grid and equipment. The power system is essentially a complex nonlinear system, and the linear control method relies on the accurate linearization of the system model, which is difficult to effectively suppress frequency oscillation caused by nonlinear factors in actual operation, while nonlinear control has strong robustness to system parameter changes and model uncertainty, and can effectively improve the dynamic response speed and stability of the system.

[0003] The existing technology research on the control scheme of the grid-forming type generally does not consider the nonlinear characteristics of the grid-forming grid-connected system, and the linear proportional integral control has unsatisfactory control effect. Therefore, it is of great significance to study the frequency control strategy for the grid-forming converter to provide efficient and reasonable frequency support for the power grid and improve the frequency modulation capability of the power grid.

[0004] In order to enable the grid-forming grid-connected system under complex working conditions to have better frequency regulation capability, a novel grid-forming converter frequency control method is needed. SUMMARY

[0005] The technical scheme of the present application provides a grid-forming converter frequency control method and system based on passive control to solve the problem of how to control the frequency of the grid-forming converter.

[0006] In order to solve the above problems, the present application provides a grid-forming converter frequency control method based on passive control, which comprises:

[0007] Converting the virtual synchronous control equation into the form of Hamilton equation, generating the Hamilton system energy function based on the coefficients of the standard form of the Hamilton equation;

[0008] Verifying whether the virtual synchronous control system satisfies the passivity based on the dissipation inequality of the passivity theory;

[0009] When it is judged that the virtual synchronous control system satisfies the passivity verification, injecting the Hamilton energy function into the virtual synchronous control system, determining the passive control law based on the expected equilibrium point of the virtual synchronous control system;

[0010] Controlling the frequency of the passive control grid-forming converter based on the passive control law.

[0011] Preferably, the step of transforming the virtual synchronization control equations into the form of Hamiltonian equations, and generating the Hamiltonian system energy function based on the coefficients of the standard form of the Hamiltonian equations, includes:

[0012] The virtual synchronization control equation is:

[0013]

[0014] Where δ is the phase difference; ω0 is the rated angular frequency of the power grid; ω g P is the network-side synchronization angular frequency; e For grid-side output active power; P ref The grid-side active power reference value is given by: J, moment of inertia, D, damping coefficient, E, internal potential amplitude, and K, reactive power integral coefficient or time constant. q Q is the reactive power-voltage droop factor. qref This is a reference value for reactive power; Q e U represents the actual reactive power output on the grid side. n U0 is the rated voltage of the power grid; U0 is the actual voltage amplitude at the grid end.

[0015] The standard form of the Hamiltonian equation is:

[0016]

[0017] Where H(x) is the system energy function; J(x) is the antisymmetric matrix, i.e., J(x) = -J T R(x) is a positive definite matrix, i.e., R(x) = R T (x)≥0;

[0018] The virtual synchronization control equations are transformed into the standard form of the Hamiltonian equations, and the resulting coefficient matrix is:

[0019]

[0020] Where g(x) is the system input matrix; u(x) is the system control input vector;

[0021] The energy function of the Hamiltonian system is:

[0022]

[0023] Preferably, the virtual synchronization control system based on the dissipation inequality verification method of the passive property theory satisfies the passive property, wherein the dissipation inequality is:

[0024]

[0025] Among them, u TThe input vector is transposed; x is the system state vector; y is the system output vector.

[0026] Preferably, when it is determined that the virtual synchronization control system satisfies the passive performance verification, a Hamiltonian energy function is injected into the virtual synchronization control system, and a passive control law is determined based on the desired equilibrium point of the virtual synchronization control system, wherein the desired equilibrium point is:

[0027]

[0028] Where, δ * ω is the phase difference reference value. * E is the reference value for angular frequency. * This is the reactive voltage reference value. This is a phase difference reference value; This is the angular frequency reference value, x3 * This serves as a reference value for the internal virtual potential amplitude.

[0029] Preferably, determining the passive control law includes:

[0030] Obtained from the standard form of the Hamiltonian equation:

[0031]

[0032]

[0033] in, J is the time derivative of the state vector x; a (x) is the dissipation matrix; R a (x) is the damping matrix; u is the control input vector; w is the control law;

[0034] Multiply both sides of equation (8) by g T (x), obtain:

[0035]

[0036] Where α represents the additional control generated by the Hamiltonian modified structure; J is selected. a (x)=0, R a (x)=diag(r a1 r a2 r a3 ), r a1 r a2 r a3 For the injection damping parameters;

[0037] Substituting the injection damping parameters into equation (10) yields:

[0038]

[0039] Based on the injected damping parameter α, the standard form of the Hamiltonian equation is opened to determine the passive control law:

[0040]

[0041] Based on another aspect of the present invention, the present invention provides a frequency control system for a grid-type converter based on passive control, the system comprising:

[0042] The generation unit is used to transform the virtual synchronization control equations into the form of Hamiltonian equations, and generate the Hamiltonian system energy function based on the coefficients of the standard form of the Hamiltonian equations.

[0043] The verification unit verifies whether the virtual synchronous control system satisfies passivity based on the dissipation inequality of the passivity theory.

[0044] The determining unit is used to inject Hamiltonian energy function into the virtual synchronous control system when it is determined that the virtual synchronous control system meets the passive verification, and to determine the passive control law based on the expected equilibrium point of the virtual synchronous control system.

[0045] The result unit is used to control the frequency of the passively controlled grid converter based on the passive control law.

[0046] Preferably, the generation unit is used to transform the virtual synchronization control equations into the form of Hamiltonian equations, generate the Hamiltonian system energy function based on the coefficients of the standard form of the Hamiltonian equations, and is further used to:

[0047] The virtual synchronization control equation is:

[0048]

[0049] Where δ is the phase difference; ω0 is the rated angular frequency of the power grid; ω g P is the network-side synchronization angular frequency; e For grid-side output active power; P ref The grid-side active power reference value is given by: J, moment of inertia, D, damping coefficient, E, internal potential amplitude, and K, reactive power integral coefficient or time constant. q Q is the reactive power-voltage droop factor. qref This is a reference value for reactive power; Q e U represents the actual reactive power output on the grid side. n U0 is the rated voltage of the power grid; U0 is the actual voltage amplitude at the grid end.

[0050] The standard form of the Hamiltonian equation is:

[0051]

[0052] Where H(x) is the system energy function; J(x) is the antisymmetric matrix, i.e., J(x) = -J T R(x) is a positive definite matrix, i.e., R(x) = R T (x)≥0;

[0053] The virtual synchronization control equations are transformed into the standard form of the Hamiltonian equations, and the resulting coefficient matrix is:

[0054]

[0055]

[0056] Where g(x) is the system input matrix; u(x) is the system control input vector;

[0057] The energy function of the Hamiltonian system is:

[0058]

[0059] Preferably, the verification unit is used to verify whether the virtual synchronous control system satisfies passivity based on the dissipation inequality of passivity theory, wherein the dissipation inequality is:

[0060]

[0061] Among them, u T The input vector is transposed; x is the system state vector; y is the system output vector.

[0062] Preferably, the determining unit is configured to, when it is determined that the virtual synchronous control system satisfies the passive performance verification, inject a Hamiltonian energy function into the virtual synchronous control system, and determine a passive control law based on the desired equilibrium point of the virtual synchronous control system, wherein the desired equilibrium point is:

[0063]

[0064] Where, δ * ω is the phase difference reference value. * E is the reference value for angular frequency. * This is the reactive voltage reference value. This is a phase difference reference value; This is the angular frequency reference value, x3 * This serves as a reference value for the internal virtual potential amplitude.

[0065] Preferably, the determining unit is used to determine the passive control law, including:

[0066] Obtained from the standard form of the Hamiltonian equation:

[0067]

[0068] in, J is the time derivative of the state vector x; a (x) is the dissipation matrix; R a (x) is the damping matrix; u is the control input vector; w is the control law;

[0069] Multiply both sides of equation (8) by g T (x), obtain:

[0070]

[0071] Where α represents the additional control generated by the Hamiltonian modified structure; J is selected. a (x)=0, R a (x)=diag(r a1 r a2 r a3 ), r a1 r a2 r a3 For the injection damping parameters;

[0072] Substituting the injection damping parameters into equation (10) yields:

[0073]

[0074] Based on the injected damping parameter α, the standard form of the Hamiltonian equation is opened to determine the passive control law:

[0075]

[0076] According to another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that, when the program is executed by a processor, it implements the steps of a frequency control method for a grid-type converter based on passive control.

[0077] According to another aspect of the present invention, the present invention provides an electronic device, characterized in that it comprises:

[0078] The aforementioned computer-readable storage medium; and

[0079] One or more processors for executing a program in the computer-readable storage medium.

[0080] This invention provides a frequency control method and system for grid-connected converters based on passive control. The method includes: transforming the virtual synchronous control equations into Hamiltonian equations; generating a Hamiltonian system energy function based on the coefficients of the standard form of the Hamiltonian equations; verifying whether the virtual synchronous control system satisfies passivity using dissipation inequalities based on passivity theory; when the virtual synchronous control system satisfies the passivity verification, injecting the Hamiltonian energy function into the virtual synchronous control system; determining the passive control law based on the expected equilibrium point of the virtual synchronous control system; and controlling the frequency of the passively controlled grid-connected converter based on the passive control law. This invention enables field testing of frequency control for grid-connected grid-connected converter systems. The implementation process is simple and effective, providing a convenient and accurate solution for field testing of frequency control in grid-connected converters. Attached Figure Description

[0081] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0082] Figure 1 This is a flowchart of a frequency control method for a grid-type converter based on passive control according to a preferred embodiment of the present invention.

[0083] Figure 2 This is a flowchart of a frequency control method for a grid-type converter based on passive control according to a preferred embodiment of the present invention.

[0084] Figure 3 This is a schematic diagram of a grid-connected system model of a grid-type converter according to a preferred embodiment of the present invention;

[0085] Figure 4 This is a block diagram of the frequency controller structure of a grid-type converter according to a preferred embodiment of the present invention;

[0086] Figure 5 This is a schematic diagram of the converter output active power, reactive power, angular frequency, and system frequency curves according to a preferred embodiment of the present invention.

[0087] Figure 6 This is a schematic diagram of the converter output active power, reactive power, angular frequency, and system frequency curves in case 2 of the preferred embodiment of the present invention.

[0088] Figure 7 This is a schematic diagram of the converter output active power, reactive power, angular frequency, and system frequency curves in case 3 of the preferred embodiment of the present invention.

[0089] Figure 8 This is a structural diagram of a grid-type converter frequency control system based on passive control according to a preferred embodiment of the present invention. Detailed Implementation

[0090] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0091] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0092] Figure 1 This is a flowchart of a frequency control method for a grid-type converter based on passive control according to a preferred embodiment of the present invention.

[0093] This invention proposes a frequency control method for grid-connected converters. It enables field testing of frequency control in grid-connected systems using grid-connected converters, and the implementation process is simple and effective, providing a convenient and accurate solution for field testing of frequency control in grid-connected converters. The frequency control method provided by this invention designs a passive controller based on passive control theory. Its control strategy is based on active frequency control and reactive voltage control in virtual synchronous control. The former provides frequency support for the grid-connected system, while the latter controls the output voltage of the grid-connected converter, enhancing overall system stability and improving the system's dynamic frequency response capability.

[0094] like Figure 1 As shown, this invention provides a frequency control method for a grid-type converter based on passive control, the method comprising:

[0095] Step 101: Transform the virtual synchronization control equations into the form of Hamiltonian equations, and generate the Hamiltonian system energy function based on the coefficients of the standard form of the Hamiltonian equations;

[0096] Preferably, the virtual synchronization control equations are transformed into Hamiltonian equations, and based on the coefficients of the standard form of the Hamiltonian equations, the energy function of the Hamiltonian system is generated, including:

[0097] The virtual synchronization control equation is:

[0098]

[0099] Where δ is the phase difference; ω0 is the rated angular frequency of the power grid; ωg P is the network-side synchronization angular frequency; e For grid-side output active power; P ref The grid-side active power reference value is given by: J, moment of inertia, D, damping coefficient, E, internal potential amplitude, and K, reactive power integral coefficient or time constant. q Q is the reactive power-voltage droop factor. qref This is a reference value for reactive power; Q e U represents the actual reactive power output on the grid side. n U0 is the rated voltage of the power grid; U0 is the actual voltage amplitude at the grid end.

[0100] The standard form of Hamilton's equations is:

[0101]

[0102] Where H(x) is the system energy function; J(x) is the antisymmetric matrix, i.e., J(x) = -J T R(x) is a positive definite matrix, i.e., R(x) = R T (x)≥0;

[0103] The virtual synchronization control equations are transformed into the standard form of the Hamiltonian equations, and the resulting coefficient matrix is:

[0104]

[0105] Where g(x) is the system input matrix; u(x) is the system control input vector;

[0106] The energy function of the Hamiltonian system is:

[0107]

[0108] This invention transforms the virtual synchronization control equations into the standard form of the Hamiltonian equations, and obtains the system energy function based on the equation coefficients.

[0109] The specific steps in designing the frequency control method for the grid-type converter of this invention include:

[0110] (1) The virtual synchronization control equation is:

[0111]

[0112] In the formula: δ is the phase difference; ω0 is the rated angular frequency of the power grid; ω g P is the network-side synchronization angular frequency; e For grid-side output active power; P ref J is the reference value for active power on the grid side; D is the moment of inertia; and D is the damping coefficient.

[0113] The standard form of Hamilton's equations is:

[0114]

[0115] In the formula: H(x) is the energy function of the system; J(x) reflects the internal interconnection structure of the system and is an antisymmetric matrix, i.e., J(x) = -J T R(x) reflects the energy dissipation characteristics of the system and is a positive definite matrix, i.e., R(x) = R T (x)≥0

[0116] The virtual synchronization control equations are transformed into the standard form of the Hamiltonian equations, and the resulting coefficient matrix is:

[0117]

[0118] The energy function of the Hamiltonian system can be obtained as follows:

[0119]

[0120] Step 102: Verify whether the virtual synchronous control system satisfies passivity based on the dissipation inequality of passivity theory;

[0121] Preferably, the virtual synchronous control system satisfies passivity by verifying the dissipation inequality based on the passiveity theory, wherein the dissipation inequality is:

[0122]

[0123] Among them, u T The input vector is transposed; x is the system state vector; y is the system output vector.

[0124] This invention verifies that the virtual synchronous control system satisfies passivity based on the dissipation inequality of passivity theory. According to passivity theory, the dissipation inequality reflecting the energy change of the system is:

[0125]

[0126] The left side of the dissipative inequality represents the energy increment of the virtual synchronous control system, and the right side represents the effect of the input on the system energy, i.e. the external energy supply. It can be seen that the system energy increment is less than the external energy injection, and the system is strictly passive.

[0127] Since J(x) is an antisymmetric matrix, its quadratic form is always 0, that is:

[0128]

[0129] This does not affect the system energy change and does not need to be considered when calculating damping injection, thus simplifying the design process of passive controllers.

[0130] Step 103: When it is determined that the virtual synchronous control system meets the passive verification, inject the Hamiltonian energy function into the virtual synchronous control system, and determine the passive control law based on the expected equilibrium point of the virtual synchronous control system.

[0131] Preferably, when it is determined that the virtual synchronous control system satisfies the passive performance verification, a Hamiltonian energy function is injected into the virtual synchronous control system, and a passive control law is determined based on the desired equilibrium point of the virtual synchronous control system, wherein the desired equilibrium point is:

[0132]

[0133] Where, δ * ω is the phase difference reference value. * E is the reference value for angular frequency. * This is the reactive voltage reference value. This is a phase difference reference value; This is the angular frequency reference value, x3 * This serves as a reference value for the internal virtual potential amplitude.

[0134] Preferably, determining the passive control law includes:

[0135] Obtained from the standard form of the Hamiltonian equation:

[0136]

[0137] in, J is the time derivative of the state vector x; a (x) is the dissipation matrix; R a (x) is the damping matrix; u is the control input vector; w is the control law;

[0138] Multiply both sides of equation (8) by g T (x), obtain:

[0139]

[0140] Where α represents the additional control generated by the Hamiltonian modified structure; J is selected. a (x)=0, R a (x)=diag(r a1 r a2 r a3 ), r a1 r a2 r a3 For the injection damping parameters;

[0141] Substituting the injection damping parameters into equation (10) yields:

[0142]

[0143] Based on the injected damping parameter α, the standard form of the Hamiltonian equation is opened to determine the passive control law:

[0144]

[0145] This invention accelerates the dissipation of system energy by injecting damping configuration into the system energy function, enabling the frequency to quickly track the reference value and thus obtaining the passive control law.

[0146] The desired equilibrium point of the virtual synchronous control system is set as follows:

[0147]

[0148] Where: δ * The phase difference reference value is Δω. * E is the reference value for angular frequency. * Reactive voltage reference value

[0149] According to Hamilton's equation, we can obtain:

[0150]

[0151] As can be seen from the above equation, the control law w can be equivalent to the change in the Hamiltonian system structure.

[0152] Multiply both sides of equation (8) by g T (x), we can obtain:

[0153]

[0154] α is an additional control generated by the Hamiltonian modified structure. For equation (10), a reasonable dissipation matrix J is set. a (x) and damping matrix R a (x) can effectively control the rate of system energy consumption, achieving the goal of optimizing system energy design. Here, J is selected. a (x)=0, R a (x)=diag(r a1 r a2 r a3 ), r a1 r a2 r a3 By injecting damping parameters, the resulting passive control law is simple and controllable.

[0155] Substituting the relevant parameters into equation (10) yields:

[0156]

[0157] Opening equation (7) yields the passive control law based on virtual synchronization control:

[0158]

[0159] Step 104: Based on the passive control law, control the frequency of the passively controlled grid-type converter.

[0160] This invention provides a frequency control method for grid-connected converters based on passive control. Building upon virtual synchronous control, it employs a nonlinear control strategy to design the frequency controller. The control principle is simple and effective, enhancing system stability. This invention has no special requirements for operating conditions and is suitable for all operating conditions under grid-connected configurations. The calculation results demonstrate good robustness. Simulation examples verify the accuracy of the frequency control method for grid-connected converters, improving the system's frequency regulation capability and showcasing its strong engineering applicability. Figure 2 As shown.

[0161] This invention is based on Figure 3 The grid-connected system model of the grid-connected converter shown in the figure further illustrates the present invention in detail, but the present invention is not limited to the examples given.

[0162] Figure 3 This demonstrates a practical grid-connected converter system, featuring concrete hardware circuitry and a control architecture that includes a VSG outer loop and voltage / current inner loops. The circuitry forms the physical foundation of the grid-connected converter and primarily consists of three parts:

[0163] Power conversion section:

[0164] DC voltage source (Udc): Provides energy to the system, which can be energy storage batteries, photovoltaic arrays, or rectified DC power.

[0165] Three-phase voltage source converter (VSC): The core component, consisting of six switching devices (such as IGBTs), is responsible for inverting direct current into alternating current.

[0166] PWM module: It is the direct drive unit of the converter. According to the instructions of the control system, it generates high-frequency switching signals to control the on and off of VSC.

[0167] Filtering stage:

[0168] This is an LCL filter, consisting of an inductor (Lf) on the inverter side, a filter capacitor (C), and an inductor (Lg) on ​​the grid side. Its main function is to filter out harmonics generated by the high-frequency switching of PWM, so that the current output from the converter to the grid is a smooth, high-quality sine wave.

[0169] Power grid interface:

[0170] The AC power source and the series resistor and inductor (Rg, Lg) on ​​the far right of the diagram represent the AC main grid to which the converter is connected and its equivalent impedance.

[0171] The frequency control method for a grid-type converter using the method provided by this invention comprises the following steps:

[0172] Step 1: Simultaneously solve the active frequency control and reactive voltage control equations in the virtual synchronous control equations, transforming them into Hamiltonian equations, where J(x) is an antisymmetric matrix and R(x) is a positive semi-definite matrix. The system energy function can be obtained by integration:

[0173]

[0174] Step 2: Based on the passive property theory, determine whether a passive controller can be designed for the virtual synchronous control system. The dissipation inequality reflecting the energy change of the system is as follows:

[0175]

[0176] The left side of the dissipative inequality represents the energy increment of the VSG control system, and the right side represents the effect of the input on the system energy, i.e. the external energy supply. It can be seen that the system energy increment is less than the external energy injection, and the system is strictly passive.

[0177] Since J(x) is an antisymmetric matrix, its quadratic form is always 0, i.e.

[0178]

[0179] This demonstrates that the virtual synchronous control system satisfies the passivity requirement, allowing for the design of passive controllers.

[0180] Step 3: Set the desired equilibrium point of the virtual synchronous control system as follows:

[0181]

[0182] Where: δ * The phase difference reference value is Δω. * E is the reference value for angular frequency. * Reactive voltage reference value

[0183] There is a linear relationship between angular frequency and system frequency; therefore, while the angular frequency tracks the reference value, the system frequency also reaches the reference value. Transforming the Hamiltonian equation yields the passive control law:

[0184]

[0185] The corresponding passive control block diagram is as follows: Figure 4 It is applied in the control of grid-type converters, replacing virtual synchronization control. The new control framework... Figure 4 Replace it with an active-frequency controller designed based on passive theory. Figure 3The traditional VSG control module in this paper can be seen as an advanced version of the traditional VSG control, optimized by passive theory. Its circuit structure is similar to... Figure 3 The same principles apply, remaining unchanged. This example demonstrates frequency control of a grid-connected system using a grid-connected converter frequency control method applicable to various faults and disturbances. Nonlinear simulation analysis is then performed under three different disturbance and fault conditions to verify the effectiveness of the method provided in this invention.

[0186] 1) Case 1

[0187] Under basic operating conditions, the system's active power reference value increases from 10kW to 15kW in 1 second and decreases from 15kW to 700W in 1.3 seconds. A comparison is made between virtual synchronous control and the frequency control method for the grid-type converter designed in this invention. Figure 5 Displays the converter output active power, reactive power, angular frequency, and system frequency curves.

[0188] 2) Case 2

[0189] The system operates normally with an active power reference value of 10kW. A 10kW load is applied at the point of common coupling at t=1s, and removed at t=1.5s. The converter output active power, reactive power, angular frequency, and system frequency curves under different control modes are shown below. Figure 6 .

[0190] 3) Case 3

[0191] A two-phase short-circuit ground fault occurs at the grid connection point at 1 second, lasting for 20 ms. Similarly, the system time-domain response curve is as follows. Figure 7 As shown.

[0192] The test results show that the frequency control method for grid-type converters designed using this invention has dynamic compensation effects and strong anti-interference capabilities. Compared with traditional virtual synchronous control, it improves the robustness of the system under uncertain conditions, speeds up the system response time, and can meet the requirements of power grid operation, thus verifying the effectiveness and applicability of the method provided by this invention.

[0193] Figure 8 This is a structural diagram of a grid-type converter frequency control system based on passive control according to a preferred embodiment of the present invention.

[0194] like Figure 8 As shown, this invention provides a frequency control system for a grid-type converter based on passive control. The system includes:

[0195] The generation unit 801 is used to transform the virtual synchronization control equations into the form of Hamiltonian equations and generate the Hamiltonian system energy function based on the coefficients of the standard form of Hamiltonian equations.

[0196] Preferably, the generation unit 801 is used to transform the virtual synchronization control equations into the form of Hamiltonian equations, generate the Hamiltonian system energy function based on the coefficients of the standard form of the Hamiltonian equations, and is also used for:

[0197] The virtual synchronization control equation is:

[0198]

[0199] Where δ is the phase difference; ω0 is the rated angular frequency of the power grid; ω g P is the network-side synchronization angular frequency; e For grid-side output active power; P ref The grid-side active power reference value is given by: J, moment of inertia, D, damping coefficient, E, internal potential amplitude, and K, reactive power integral coefficient or time constant. q Q is the reactive power-voltage droop factor. qref This is a reference value for reactive power; Q e U represents the actual reactive power output on the grid side. n U0 is the rated voltage of the power grid; U0 is the actual voltage amplitude at the grid end.

[0200] The standard form of Hamilton's equations is:

[0201]

[0202] Where H(x) is the system energy function; J(x) is the antisymmetric matrix, i.e., J(x) = -J T R(x) is a positive definite matrix, i.e., R(x) = R T (x)≥0;

[0203] The virtual synchronization control equations are transformed into the standard form of the Hamiltonian equations, and the resulting coefficient matrix is:

[0204]

[0205] Where g(x) is the system input matrix; u(x) is the system control input vector;

[0206] The energy function of the Hamiltonian system is:

[0207]

[0208] Verification unit 802 verifies whether the virtual synchronous control system satisfies passivity based on the dissipation inequality of passivity theory;

[0209] Preferably, the verification unit 802 is used to verify whether the virtual synchronous control system satisfies passivity based on the dissipation inequality of passivity theory, wherein the dissipation inequality is:

[0210]

[0211] Among them, u T The input vector is transposed; x is the system state vector; y is the system output vector.

[0212] The determining unit 803 is used to inject Hamiltonian energy function into the virtual synchronous control system when it is determined that the virtual synchronous control system meets the passive verification, and determine the passive control law based on the expected equilibrium point of the virtual synchronous control system.

[0213] Preferably, the determining unit 803 is used to inject a Hamiltonian energy function into the virtual synchronous control system when it is determined that the virtual synchronous control system meets the passiveity verification, and to determine the passive control law based on the expected equilibrium point of the virtual synchronous control system, wherein the expected equilibrium point is:

[0214]

[0215] Where, δ * ω is the phase difference reference value. * E is the reference value for angular frequency. * This is the reactive voltage reference value. This is a phase difference reference value; This is the angular frequency reference value, x3 * This serves as a reference value for the internal virtual potential amplitude.

[0216] Preferably, the determining unit 803 is used to determine the passive control law, including:

[0217] Obtained from the standard form of the Hamiltonian equation:

[0218]

[0219] in, J is the time derivative of the state vector x; a (x) is the dissipation matrix; R a (x) is the damping matrix; u is the control input vector; w is the control law;

[0220] Multiply both sides of equation (8) by g T (x), obtain:

[0221]

[0222] Where α represents the additional control generated by the Hamiltonian modified structure; J is selected. a (x)=0, R a (x)=diag(r a1 r a2 r a3), r a1 r a2 r a3 For the injection damping parameters;

[0223] Substituting the injection damping parameters into equation (10) yields:

[0224]

[0225] Based on the injected damping parameter α, the standard form of the Hamiltonian equation is opened to determine the passive control law:

[0226]

[0227] Result unit 804 is used to control the frequency of a passively controlled grid converter based on a passive control law.

[0228] The present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method for frequency control of a grid-type converter based on passive control.

[0229] This invention provides an electronic device, comprising:

[0230] The aforementioned computer-readable storage medium; and

[0231] One or more processors for executing programs in a computer-readable storage medium.

[0232] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0233] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0234] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0235] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0236] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0237] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0238] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

[0239] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

Claims

1. A frequency control method for a grid-type converter based on passive control, the method comprising: The virtual synchronization control equations are transformed into Hamiltonian equations, and the Hamiltonian system energy function is generated based on the coefficients of the standard form of the Hamiltonian equations. Verify whether the virtual synchronous control system satisfies passivity using the dissipation inequality based on the passive theory; When it is determined that the virtual synchronous control system meets the passive verification, the Hamiltonian energy function is injected into the virtual synchronous control system, and the passive control law is determined based on the expected equilibrium point of the virtual synchronous control system. Based on the passive control law, the frequency of the passively controlled grid-type converter is controlled.

2. The method according to claim 1, wherein transforming the virtual synchronization control equations into Hamiltonian equations and generating the Hamiltonian system energy function based on the coefficients of the standard form of the Hamiltonian equations comprises: The virtual synchronization control equation is: Where δ is the phase difference; ω0 is the rated angular frequency of the power grid; ω g P is the network-side synchronization angular frequency; e For grid-side output active power; P ref The grid-side active power reference value is given by: J, moment of inertia, D, damping coefficient, E, internal potential amplitude, and K, reactive power integral coefficient or time constant. q Q is the reactive power-voltage droop factor. qref This is a reference value for reactive power; Q e U represents the actual reactive power output on the grid side. n U0 is the rated voltage of the power grid; U0 is the actual voltage amplitude at the grid end. The standard form of the Hamiltonian equation is: Where H(x) is the system energy function; J(x) is the antisymmetric matrix, i.e., J(x) = -J T R(x) is a positive definite matrix, i.e., R(x) = R T (x)≥0; The virtual synchronization control equations are transformed into the standard form of the Hamiltonian equations, and the resulting coefficient matrix is: Where g(x) is the system input matrix; u(x) is the system control input vector; The energy function of the Hamiltonian system is:

3. The method according to claim 2, wherein the virtual synchronization control system based on the dissipation inequality verification of passivity theory satisfies passivity, wherein the dissipation inequality is: in, u T The input vector is transposed; x is the system state vector; y is the system output vector.

4. The method according to claim 3, wherein when it is determined that the virtual synchronous control system satisfies the passive verification, a Hamiltonian energy function is injected into the virtual synchronous control system, and a passive control law is determined based on the desired equilibrium point of the virtual synchronous control system, wherein the desired equilibrium point is: in, δ * ω is the phase difference reference value. * E is the reference value for angular frequency. * This is the reactive voltage reference value. This is a phase difference reference value; This is the angular frequency reference value, x3 * This serves as a reference value for the internal virtual potential amplitude.

5. The method according to claim 4, wherein determining the passive control law comprises: Obtained from the standard form of the Hamiltonian equation: in, J is the time derivative of the state vector x; a (x) is the dissipation matrix; R a (x) is the damping matrix; u is the control input vector; w is the control law; Multiply both sides of equation (8) by g T (x), obtain: Where α represents the additional control generated by the Hamiltonian modified structure; J is selected. a (x)=0, R a (x)=diag(r a1 r a2 r a3 ), r a1 r a2 r a3 For the injection damping parameters; Substituting the injection damping parameters into equation (10) yields: Based on the injected damping parameter α, the standard form of the Hamiltonian equation is opened to determine the passive control law:

6. A frequency control system for a grid-type converter based on passive control, the system comprising: The generation unit is used to transform the virtual synchronization control equations into the form of Hamiltonian equations, and generate the Hamiltonian system energy function based on the coefficients of the standard form of the Hamiltonian equations. The verification unit verifies whether the virtual synchronous control system satisfies passivity based on the dissipation inequality of the passivity theory. The determining unit is used to inject Hamiltonian energy function into the virtual synchronous control system when it is determined that the virtual synchronous control system meets the passive verification, and to determine the passive control law based on the expected equilibrium point of the virtual synchronous control system. The result unit is used to control the frequency of the passively controlled grid converter based on the passive control law.

7. The system according to claim 6, wherein the generation unit is configured to transform the virtual synchronization control equations into the form of Hamiltonian equations, and generate a Hamiltonian system energy function based on the coefficients of the standard form of the Hamiltonian equations, and is further configured to: The virtual synchronization control equation is: in, δ is the phase difference; ω0 is the rated angular frequency of the power grid; ω g P is the network-side synchronization angular frequency; e For grid-side output active power; P ref The grid-side active power reference value is given by: J, moment of inertia, D, damping coefficient, E, internal potential amplitude, and K, reactive power integral coefficient or time constant. q Q is the reactive power-voltage droop factor. qref This is a reference value for reactive power; Q e U represents the actual reactive power output on the grid side. n U0 is the rated voltage of the power grid; U0 is the actual voltage amplitude at the grid end. The standard form of the Hamiltonian equation is: Where H(x) is the system energy function; J(x) is the antisymmetric matrix, i.e., J(x) = -J T R(x) is a positive definite matrix, i.e., R(x) = R T (x)≥0; The virtual synchronization control equations are transformed into the standard form of the Hamiltonian equations, and the resulting coefficient matrix is: Where g(x) is the system input matrix; u(x) is the system control input vector; The energy function of the Hamiltonian system is:

8. The system according to claim 7, wherein the verification unit is used to verify whether the virtual synchronous control system satisfies passivity based on the dissipation inequality of passivity theory, wherein the dissipation inequality is: in, u T The input vector is transposed; x is the system state vector; y is the system output vector.

9. The system according to claim 8, wherein the determining unit is configured to, when it is determined that the virtual synchronous control system satisfies the passive performance verification, inject a Hamiltonian energy function into the virtual synchronous control system, and determine a passive control law based on the desired equilibrium point of the virtual synchronous control system, wherein the desired equilibrium point is: in, δ * ω is the phase difference reference value. * E is the reference value for angular frequency. * This is the reactive voltage reference value. This is a phase difference reference value; This is the angular frequency reference value, x3 * This serves as a reference value for the internal virtual potential amplitude.

10. The system according to claim 9, wherein the determining unit is configured to determine a passive control law, comprising: Obtained from the standard form of the Hamiltonian equation: in, J is the time derivative of the state vector x; a (x) is the dissipation matrix; R a (x) is the damping matrix; u is the control input vector; w is the control law; Multiply both sides of equation (8) by g T (x), obtain: Where α represents the additional control generated by the Hamiltonian modified structure; J is selected. a (x)=0, R a (x)=diag(r a1 r a2 r a3 ), r a1 r a2 r a3 For the injection damping parameters; Substituting the injection damping parameters into equation (10) yields: Based on the injected damping parameter α, the standard form of the Hamiltonian equation is opened to determine the passive control law:

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method as described in any one of claims 1-5.

12. An electronic device, characterized in that, include: The computer-readable storage medium as described in claim 11; as well as One or more processors for executing a program in the computer-readable storage medium.

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