CN115882468B - Virtual synchronous control method based on port energy remodeling - Google Patents
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Abstract
The invention provides a virtual synchronization control method based on port energy remodeling, which comprises the following steps: establishing a dynamic model based on a virtual synchronous generator incorporated into an infinite power grid system, modeling an energy function corresponding to the dynamic model of the virtual synchronous generator incorporated into the infinite power grid system according to the dynamic model of the virtual synchronous generator incorporated into the infinite power grid system, further establishing a Hamiltonian controlled system mathematical model corresponding to the virtual synchronous generator incorporated into the infinite power grid system, deriving parameters of the established Hamiltonian controlled system mathematical model, and checking zero state detectability of the Hamiltonian controlled system mathematical model; according to the Hamiltonian controlled system mathematical model and the derived parameters, reversely deducing to obtain the established Hamiltonian controlled system mathematical model at the balance point x 0 And a control strategy corresponding to the exciting voltage regulating quantity which is gradually stabilized. The invention can effectively inhibit the power oscillation induced by the fault working condition and improve the voltage and frequency quality of the grid-connected end of the fan.
Description
Technical Field
The invention belongs to the field of operation stability analysis of power systems, relates to a virtual synchronization control method based on port energy remodeling, and particularly relates to a virtual synchronization control method based on port energy remodeling for inhibiting power oscillation induced by fault working conditions.
Background
Along with the proposal of the 'double carbon' target in China, renewable energy sources mainly comprising wind energy and photovoltaic are greatly developed, and a traditional synchronous generator mainly comprising traditional fossil energy sources is widely replaced, so that inertia and damping of a power system are reduced, thereby restricting the frequency modulation and voltage regulation capability of the system and threatening the safe and stable operation of a power grid.
The virtual synchronous generator technology is widely applied to solve the problems of weak damping and low inertia caused by power electronization of a novel power system. Some scholars propose a virtual inertia and virtual damping parameter optimization design method of a virtual synchronization micro-grid. Some scholars propose a virtual synchronous generator parameter self-adaptive control strategy based on fuzzy control, and according to angular frequency deviation and change rate thereof, moment of inertia and damping coefficient are adjusted in real time under different working conditions, so that the stability of micro-grid frequency is improved. Most of the improved virtual control strategies are developed based on linearized system models. However, the power system is a complex nonlinear system, and many linear control methods are difficult to be applied, while the generalized Hamiltonian system provides a new idea for solving the nonlinear system control problem. Some scholars design a novel multi-machine excitation and unified power flow nonlinear coordination controller based on generalized dissipation Hamiltonian theory, and the influence of uncertain parameter disturbance on a system stability controller in a multi-machine power system is solved. Some scholars propose a virtual synchronous generator control method based on the dissipation Hamiltonian theory, the anti-interference capability and stability of the system are improved by using an active disturbance rejection control decoupling algorithm, and parameter perturbation and coupling are eliminated while virtual inertia and positive damping are provided for the system. Some scholars have designed power system controllers that suppress low frequency oscillations based on the Hamiltonian of the power system energy and have proposed additional damping design methods. In a grid-connected system of a wind power plant, virtual synchronous generator control is introduced into a control strategy of a wind turbine generator, so that the stability of the system can be effectively improved, but power oscillation with different degrees can still occur under certain fault disturbance.
Disclosure of Invention
Aiming at the defects or improvement demands of the prior art, the invention provides a virtual synchronous control method based on port energy remodeling, which can inhibit power oscillation induced by fault working conditions and improve the voltage and frequency quality of a fan grid-connected end.
In order to achieve the above object, the present invention provides a virtual synchronization control method based on port energy remodeling, including:
step S1: establishing a dynamic model based on the virtual synchronous generator incorporated into an infinite power grid system;
step S2: according to the dynamic model of the virtual synchronous machine integrated into the infinite power grid system established in the step S1, an energy function corresponding to the dynamic model of the virtual synchronous machine integrated into the infinite power grid system is molded, a Hamiltonian controlled system mathematical model corresponding to the virtual synchronous machine integrated into the infinite power grid system is further established, parameters of the established Hamiltonian controlled system mathematical model are further derived, and finally zero state detectability of the established Hamiltonian controlled system mathematical model is verified;
step S3: according to the Hamiltonian controlled system mathematical model established in the step S2 and the derived parameters, reversely pushing to obtain the Hamiltonian controlled system mathematical model at the balance point x 0 And a control strategy corresponding to the exciting voltage regulating quantity which is gradually stabilized.
Further, step S1 establishes a dynamic model based on the incorporation of the virtual synchronous generator into the infinite power grid system, specifically including:
in a virtual synchronous motor model of a new energy station, taking the control angle of a fan power grid side converter as a control variable, and taking the control angle as a testTaking into consideration excitation control equation and motion differential equation of virtual synchronous generator, establishing equation of dynamic model of virtual synchronous generator incorporated into infinite power grid system, as formulaAs shown in the drawing,
parameters asShown;
wherein delta is the power angle of the virtual synchronous generator, omega m And omega is the mechanical angular velocity per unit value and the electrical angular velocity of the virtual synchronous generator respectively, H is the inertia time constant of the virtual synchronous generator, and P m And P e The mechanical torque and the electromagnetic torque of the virtual synchronous generator are respectively, D is the damping of the virtual synchronous generator, E q ' and E fds The quadrature axis transient potential and the excitation voltage during the steady state operation of the system of the virtual synchronous generator are respectively, u f For adjusting exciting voltage, T d0 ' is the direct axis transient short-circuit time constant, X of a virtual synchronous generator d And X d ' direct-axis steady-state reactance and direct-axis transient reactance of virtual synchronous generator, respectively, U s =1+0° is infinite grid voltage, X T1 To boost and change T1 reactance, X T2 To boost and change T2 reactance, X L To be the line reactance, X dΣ And X dΣ ' steady state equivalent reactance and transient equivalent reactance, respectively.
Further, the step S2 specifically includes:
s2.1: according to the course of the dynamic model of the virtual synchronous generator incorporated into the infinite power grid system, shaping an energy function H (x) corresponding to the model, namely a Hamiltonian function, deriving the shaped energy function H (x), referring to a generalized Hamiltonian controlled system model, and establishing a mathematical model of the Hamiltonian controlled system corresponding to the virtual synchronous generator incorporated into the infinite power grid system;
s2.2: the virtual synchronous generator established according to the step S2.1 is integrated into a Hamiltonian controlled system mathematical model corresponding to an infinite power grid system, and furtherDeducing a system damping matrix R (x), a system structure matrix J (x) and an input variable control matrix g (x) to deduce specific parameters of a mathematical model of the Hamiltonian controlled system, which is formed by merging the built virtual synchronous generator into an infinite power grid system, and finally checking zero-state detectability of the built Hamiltonian controlled system according to the deduced parameters to ensure that the Hamiltonian controlled system is at a balance point x 0 The position is asymptotically stable.
Further, the step S2.1 of shaping the energy function H (x) of the virtual synchronous machine injected into the power grid includes:
first, an energy function is established:
h (x) is then applied to the state variables omega, delta, E q ' bias derivation, results such as
Shown;
referring to the generalized Hamiltonian controlled system model equation:
and is combined with
Dynamic model equation incorporated into infinite grid system according to established virtual synchronous machineAnd->Establishing a mathematical model of a Hamiltonian controlled system corresponding to the virtual synchronous machine incorporated into an infinite power grid system:
wherein,gradients over time for state variables; j (x) is a system structure matrix, which is an antisymmetric matrix; r (x) is a system damping matrix which is a semi-positive definite symmetric matrix; u and y are conjugate variables representing input and output vectors, respectively; g (x) is an input vector control matrix, g T (x) Transpose the matrix thereof.
Further, the step S2.2 of deriving specific parameters of the mathematical model of the built virtual synchronous generator incorporated into the hamilton controlled system corresponding to the infinitely large power grid system includes:
firstly, the built virtual synchronous machine is integrated into a Hamiltonian controlled system mathematical model corresponding to an infinite power grid systemAnd the established equation of the virtual synchronous machine incorporated into the dynamic model of an infinite grid system ∈>Obtaining a coefficient matrix:
since R (x) is a semi-positive definite symmetric matrix, satisfy R (x) =r T (x) Not less than 0, J (x) is an antisymmetric matrix, satisfying J (x) = -J T (x) And deriving a system damping matrix R (x), a system structure matrix J (x) and an input variable control matrix g (x) respectively as follows:
finally, an output equation is obtained:
the specific parameters of the Hamiltonian controlled system corresponding to the built virtual synchronous machine incorporated into the infinite power grid system are obtained through deduction;
to ensure that is built upHamiltonian controlled system at balance point x 0 Is asymptotically stable, the established system must meet zero state detectability,obtaining the maximum invariable subset of the convergence of the Hamiltonian controlled system corresponding to the built virtual synchronous machine incorporated into the infinite power grid system, as +.>As shown, the invariant subset is the balance point of the system, thus satisfying zero state detectability.
Further, the step S3 specifically includes:
firstly, according to the zero state detectability of the system, when the control strategy u corresponding to the exciting voltage regulating quantity is known f Satisfy the following requirementsWhen K is positive definite matrix, the built virtual synchronous machine is integrated into Hamiltonian controlled system corresponding to infinite power grid system at balance point x 0 The position is asymptotically stable;
according to the established virtual synchronous machine, the virtual synchronous machine is integrated into a Hamiltonian controlled system corresponding to an infinite power grid system and the deduced parameters, and the control strategy u corresponding to the exciting voltage regulating quantity is obtained by back-pushing f ：
Wherein k is 1 And the value of not less than 0 is a positive feedback control proportional coefficient, and a control strategy u corresponding to the exciting voltage regulating quantity is obtained by utilizing reverse thrust f Establishing a complete control model of a virtual synchronous generator incorporated into an infinite grid system based on port energy remodeling, wherein the port is controlled by Hamiltonian feedback control u f The excitation link input end is connected with the virtual synchronous generator and used for inhibiting the virtual synchronous generator from being integrated into the oscillation of an infinite power grid system, wherein each parameter in the model is as shown in the formulaShown as X d And X d ' direct-axis steady-state reactance and direct-axis transient reactance of virtual synchronous generator, T respectively d0 ' is the direct axis transient short-circuit time constant, X of a virtual synchronous generator d∑ And X d∑ ' steady state equivalent reactance and transient equivalent reactance, respectively.
In general, the above technical solutions conceived by the present invention, compared with the prior art, enable the following beneficial effects to be obtained:
1. the virtual synchronous control method based on the port energy remodeling can effectively inhibit power oscillation induced by fault working conditions;
2. the virtual synchronous control method based on the port energy remodeling can improve the voltage and frequency quality of the parallel network end of the fan.
Drawings
FIG. 1 is a flow chart of a virtual synchronization control method based on port energy remodeling provided by an embodiment of the invention;
FIG. 2 is a diagram of a virtual synchronous generator model provided by an embodiment of the present invention;
FIG. 3 is a model diagram of a wind farm accessing infinity grid provided by an embodiment of the present invention;
FIG. 4 is a diagram of a wind farm with or without a VSG provided by an embodiment of the present invention;
FIG. 5 is a voltage fluctuation diagram of the presence or absence of VSG provided by an embodiment of the present invention;
FIG. 6 is a current ripple diagram with or without VSG provided by an embodiment of the present invention;
FIG. 7 is a diagram of a wind farm with or without a VSG provided by an embodiment of the present invention;
FIG. 8 is a diagram of a wind farm with or without PCH provided by an embodiment of the present invention;
FIG. 9 is a voltage waveform diagram of whether PCH is present or not provided by an embodiment of the present invention;
FIG. 10 is a current ripple diagram with or without PCH provided by an embodiment of the present invention;
fig. 11 is a rotational speed fluctuation diagram of the VSG and PCH according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the particular embodiments described herein are illustrative only and are not limiting upon the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
Fig. 1 is a flowchart of a virtual synchronization control method based on port energy remodeling according to an embodiment of the present invention, where the method includes the following steps:
s1: and establishing a dynamic model based on the incorporation of the virtual synchronous generator into an infinite power grid system.
In the embodiment of the present invention, step S1 may be implemented by:
taking the example of establishing a wind power plant to be integrated into an infinite power grid, the established virtual synchronous control model is shown in fig. 2, and the wind power plant grid-connected model is shown in fig. 3. In a virtual synchronous motor model of a new energy station, taking the angle controlled by a fan power grid side converter as a control variable, taking an excitation control equation and a motion differential equation of a virtual synchronous generator into consideration, and establishing an equation of a dynamic model of the virtual synchronous machine incorporated into a large power grid system, wherein the equation is shown in the specificationAs shown in the drawing,
parameters asAs shown.
Wherein delta is the power angle of the virtual synchronous generator, omega m And omega is the mechanical angular velocity per unit value and the electrical angular velocity of the virtual synchronous generator respectively, H is the inertia time constant of the virtual synchronous generator, and P m And P e The mechanical torque and the electromagnetic torque of the virtual synchronous generator are respectively, D is the damping of the virtual synchronous generator, E q ' and E fds Cross-axis transient potential and system steady state operation of virtual synchronous generatorsExciting voltage at time, u f For adjusting exciting voltage, T d0 ' is the direct axis transient short-circuit time constant, X of a virtual synchronous generator d And X d ' direct-axis steady-state reactance and direct-axis transient reactance of virtual synchronous generator respectively, U s =1+0° is infinite grid voltage, X T1 To boost and change T1 reactance, X T2 To boost and change T2 reactance, X L To be the line reactance, X d∑ And X d∑ ' steady state equivalent reactance and transient state equivalent reactance, respectively.
In fig. 3, rated power of each wind driven generator in the wind power plant is 1.5MW, voltage of a bus at an outlet of the fan is 575V, a 25kV bus is connected through a single fan boost transformer with rated capacity of 1.75MW, a 25kV/120kV boost transformer with rated capacity of 47MVA is connected through a power transmission line, and finally, an infinite power grid is connected through a current limiting reactor with rated capacity of 2500 MVA. The power grid frequency is 60Hz, the back-to-back device capacitance is 0.01C, and the capacitance reference voltage V dc Take 1150V, E 0 The value is 155/575V. Damping D of the virtual synchronous generator is 5, inertia time constant H is 5.04, k u The value is 0.035. The parameters in the port controlled pseudo-hamilton system are set as follows: direct-axis transient short-circuit time constant T of virtual synchronous generator d0’ Set direct axis reactance X of virtual synchronous generator with value of 1.5 d And a direct axis transient reactance X d ' take on values of 0.5 and 0.3, respectively, 25kV line reactance X L The value is 0.105.
S2: and (3) according to the dynamic model of the virtual synchronous machine integrated into the infinite power grid system established in the step (S1), modeling an energy function corresponding to the dynamic model of the virtual synchronous machine integrated into the infinite power grid system, further establishing a Hamiltonian controlled system mathematical model corresponding to the virtual synchronous generator integrated into the infinite power grid system, further deriving parameters of the established Hamiltonian controlled system mathematical model, and finally checking zero state detectability of the established Hamiltonian controlled system mathematical model.
In the embodiment of the present invention, step S2 may be implemented by:
s2.1: according to the course of the dynamic model of the virtual synchronous generator incorporated into the infinite power grid system, shaping an energy function H (x) corresponding to the model, namely a Hamiltonian function, deriving the shaped energy function H (x), referring to a generalized Hamiltonian controlled system model, and establishing a mathematical model of the Hamiltonian controlled system corresponding to the virtual synchronous generator incorporated into the infinite power grid system; the method comprises the following steps:
shaping the energy function H (x), i.e. Hamiltonian, of the virtual synchronous machine injected into the network, e.g.As shown in the drawing,
h (x) is applied to state variables omega, delta and E respectively q ' bias derivation, results such asAs shown.
Referring to the generalized Hamiltonian controlled system model equation:
and incorporates the dynamic model equation of infinite grid system according to the established virtual synchronous machine
And->Establishing a mathematical model of a Hamiltonian controlled system corresponding to the virtual synchronous machine incorporated into an infinite power grid system:
wherein,gradients over time for state variables; j (x) is a system structure matrix, which is an antisymmetric matrix; r (x) is a system damping matrix which isA semi-positive definite symmetric matrix; u and y are conjugate variables representing input and output vectors, respectively; g (x) is an input vector control matrix, g T (x) Transpose the matrix thereof.
S2.2: according to the mathematical model of the Hamiltonian controlled system corresponding to the virtual synchronous generator integrated into the infinite power grid system established in the step S2.1, further deriving a system damping matrix R (x), a system structure matrix J (x) and an input variable control matrix g (x), thereby deriving specific parameters of the mathematical model of the Hamiltonian controlled system corresponding to the established virtual synchronous generator integrated into the infinite power grid system, and finally checking zero-state detectability of the established Hamiltonian controlled system according to the derived parameters to ensure that the Hamiltonian controlled system is at a balance point x 0 The position is asymptotically stable.
The step S2.2 of deriving specific parameters of the mathematical model of the hamilton controlled system corresponding to the established virtual synchronous generator incorporated into the infinite power grid system includes:
firstly, the built virtual synchronous machine is integrated into a Hamiltonian controlled system mathematical model corresponding to an infinite power grid systemAnd the established equation of the virtual synchronous machine incorporated into the dynamic model of an infinite grid system ∈>Obtaining a coefficient matrix:
since R (x) is a semi-positive definite symmetric matrix, satisfy R (x) =r T (x) Not less than 0, J (x) is an antisymmetric matrix, satisfying J (x) = -J T (x) And deriving a system damping matrix R (x), a system structure matrix J (x) and an input variable control matrix g (x) respectively as follows:
finally, an output equation is obtained:
the specific parameters of the Hamiltonian controlled system corresponding to the built virtual synchronous machine incorporated into the infinite power grid system are obtained through deduction;
to ensure that the established Hamiltonian controlled system is at the equilibrium point x 0 Is asymptotically stable, the established system must meet zero state detectability,obtaining the maximum invariable subset converged by the Hamiltonian controlled system corresponding to the built virtual synchronous machine incorporated into an infinite power grid system, wherein the maximum invariable subset is shown as +.>As shown, the invariant subset is the balance point of the system, thus satisfying zero state detectability.
S3: according to the Hamiltonian controlled system mathematical model established in the step S2 and the derived parameters, reversely pushing to obtain the Hamiltonian controlled system mathematical model at the balance point x 0 And a control strategy corresponding to the exciting voltage regulating quantity which is gradually stabilized.
In the embodiment of the present invention, step S3 may be implemented by:
for the purpose ofThe nonlinear controlled Hamiltonian system shown, design control strategy u f The method meets the following conditions: />Wherein K is a positive definite matrix, which can ensure that the nonlinear controlled Hamiltonian system is at the balance point x 0 The position is asymptotically stable.
Further available asShown in the figureNonlinear controlled hamilton system. Constructing a non-linear controlled Hamiltonian system Liepnough function H (x), of the formula H (x) =H (x) -H (x 0 ) As shown. Because K is a positive definite matrix and R is a semi-positive definite matrix, the derivative of h (x) is less than or equal to 0, as shown in the formulaAs shown. The authorities->When μ=0, y=0 is easily inferred. The zero state detectability of the system can also be used to know that the nonlinear controlled Hamiltonian system is at the balance point x under the action of the control rate mu 0 The position is gradually stable.
According to the principle described above, there is a satisfied type
The control law shown makes the nonlinear controlled Hamiltonian system progressively stable. Wherein each parameter in the model is as formulaShown as X d And X d ' direct-axis steady-state reactance and direct-axis transient reactance of virtual synchronous generator, T respectively d0 ' is the direct axis transient short-circuit time constant, X of a virtual synchronous generator d∑ And X d∑ ' steady state equivalent reactance and transient state equivalent reactance respectively
Wherein k is 1 And the ratio is equal to or greater than 0, and the positive feedback control ratio is equal to or greater than 0. Virtual synchronous generator model based on port energy remodelling and established by utilizing port controlled Hamiltonian principle, PCH feedback control u f The system is connected with the input end of the excitation link of the virtual synchronous generator and is used for realizing stable control of the system.
And analyzing the simulation results of the embodiment, and respectively performing fault simulation tests in a power grid model containing VSG control and no VSG control when the capacity of a wind field is 9MW and the wind speed of the wind field is 15m/s, namely, generating three-phase grounding short-circuit faults on the power grid side of the power transmission line at 0.1s and cutting the faults at 0.2 s. Simulation results are shown in fig. 4-5, respectively. When the wind power plant is not controlled by a virtual synchronous generator (SVG), after a three-phase short circuit fault occurs, the output active power of the wind power plant fluctuates greatly, after 1.5s, the output power of the wind power plant oscillates in a constant-amplitude subsynchronous manner with the occurrence frequency of about 6HZ, the active fluctuation amplitude is stabilized between-1 pu and 2pu, the voltage fluctuation amplitude of an outlet bus of the wind power plant is stabilized between 1.0pu and 2.5pu, the current fluctuation amplitude is stabilized between 1.0pu and 1.5pu, as shown in figures 4-6 respectively, and the wind power plant cannot normally operate at the moment. When the wind power plant adopts a virtual synchronous generator (SVG) control mode, after a three-phase short circuit fault occurs, the fluctuation amplitude of the output active power of the wind power plant is smaller, after 1.5s, the output active power is basically stabilized at about 1.0pu, and the voltage and the current of an outlet bus of the wind power plant are not greatly fluctuated, as shown in figures 4-6 respectively. Therefore, the new energy station adopts a virtual synchronous generator (SVG) control mode to improve the stability of the power system during fault disturbance.
When the capacity of the wind field is 15MW and the wind speed of the wind field is 17m/s, the same fault simulation test as above is carried out in a power grid model with VSG control and without VSG control respectively, and the wind field output active fluctuation curve is shown in figure 7. Compared with the output power of the wind power plant without VSG control, the fluctuation amplitude of the output power of the wind power plant with VSG control is greatly reduced, but stable power oscillation with smaller amplitude and frequency of 6HZ still exists, namely the VSG control cannot completely eliminate the power oscillation induced by the short circuit fault under the working condition.
In order to further restrain power oscillation caused by faults on the basis of virtual synchronous control of a wind farm, in a power grid model with VSG and PCH control and a power grid model with VSG and PCH control, fault simulation tests are carried out, namely three-phase grounding short-circuit faults occur on the power grid side of the power transmission line at 0.03s, faults are cut off at 0.04s, and simulation results are shown in figures 8-10.
When the virtual synchronous generator control mode based on port controlled Hamiltonian is adopted, after 1.2s failure, the output active power of the system is basically stabilized at about 1.0pu, and as shown in FIG. 8, compared with the control mode without PCH, the output power oscillation of the wind power plant is further suppressed. After stabilization, the periodic fluctuations of the wind farm outlet bus voltage and current are substantially eliminated, stabilizing around 1.0pu and 2.0pu, respectively, as shown in the purple curves of FIGS. 9-10. Therefore, the virtual synchronous power generation control based on the port-controlled Hamiltonian can effectively restrain power oscillation possibly caused by system faults and ensure the system voltage and current quality.
When no SVG control mode or only SVG control but no PCH control mode is adopted, the rotor rotation speed is obviously fluctuated, as shown in figure 11, and the virtual synchronous generator control mode based on port controlled Hamiltonian is adopted, after fault recovery, the rotor rotation speed is always kept stable, and therefore the frequency quality of the system is improved.
This example demonstrates the feasibility of the proposed virtual synchronous control method based on port energy remodeling, and the proposed strategy can effectively suppress power oscillation caused by short-circuit fault, and improve system voltage and frequency quality.
It is noted that each step/component described in this application may be split into more steps/components, or two or more steps/components or portions of the operations of steps/components may be combined into new steps/components, as needed for implementation, to achieve the objects of the present invention.
Although the invention uses more terms of wind farm, virtual synchronous generator, port energy remodelling, port controlled hamilton method, power oscillation, etc., the possibility of using other terms is not precluded. These terms are used merely for convenience in describing and explaining the nature of the invention; they are to be interpreted as any additional limitation that is not inconsistent with the spirit of the present invention.
It should be understood that the foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (3)
1. A virtual synchronous control method based on port energy remodeling is characterized by comprising the following steps:
step S1: establishing a dynamic model based on the virtual synchronous generator incorporated into an infinite power grid system;
step S2: according to the dynamic model of the virtual synchronous machine integrated into the infinite power grid system established in the step S1, an energy function corresponding to the dynamic model of the virtual synchronous machine integrated into the infinite power grid system is molded, so that a Hamiltonian controlled system mathematical model corresponding to the virtual synchronous machine integrated into the infinite power grid system is established, parameters of the established Hamiltonian controlled system mathematical model are further obtained through deduction, and finally zero state detectability of the established Hamiltonian controlled system mathematical model is verified;
step S3: according to the Hamiltonian controlled system mathematical model established in the step S2 and the derived parameters, reversely pushing to obtain the Hamiltonian controlled system mathematical model at the balance point x 0 A control strategy corresponding to the exciting voltage regulating quantity which is asymptotically stable;
step S1, a dynamic model based on the incorporation of a virtual synchronous generator into an infinite power grid system is established, and the method specifically comprises the following steps:
in a virtual synchronous motor model of a new energy station, taking the angle controlled by a fan power grid side converter as a control variable, taking an excitation control equation and a motion differential equation of a virtual synchronous generator into consideration, and establishing an equation of a dynamic model of the virtual synchronous generator incorporated into an infinite power grid system, wherein the equation is as followsAs shown in the drawing,
parameters asShown;
wherein delta is the power angle of the virtual synchronous generator, omega m And ω is the mechanical angular velocity per unit value and the electrical angular velocity of the virtual synchronous generator, respectively, H is the inertia time constant of the virtual synchronous generator, P m And P e The mechanical torque and the electromagnetic torque of the virtual synchronous generator are respectively, D is the damping of the virtual synchronous generator, E q ' and E fds The quadrature axis transient potential and the excitation voltage during the steady state operation of the system of the virtual synchronous generator are respectively, u f For adjusting exciting voltage, T d0 ' is the direct axis transient short-circuit time constant, X of a virtual synchronous generator d And X d ' direct-axis steady-state reactance and direct-axis transient reactance of virtual synchronous generator, respectively, U s =1+0° is infinite grid voltage, X T1 To boost and change T1 reactance, X T2 To boost and change T2 reactance, X L To be the line reactance, X d∑ And X d∑ ' steady state equivalent reactance and transient equivalent reactance, respectively;
the step S2 specifically comprises the following steps:
s2.1: according to an equation of a dynamic model of the virtual synchronous generator incorporated into an infinite power grid system, modeling an energy function H (x) corresponding to the model, namely a Hamiltonian function, deriving the modeled energy function H (x), referring to a generalized Hamiltonian controlled system model, and establishing a Hamiltonian controlled system mathematical model corresponding to the virtual synchronous generator incorporated into the infinite power grid system;
s2.2: according to the mathematical model of the Hamiltonian controlled system corresponding to the virtual synchronous generator integrated into the infinite grid system established in the step S2.1, further deriving a system damping matrix R (x), a system structure matrix J (x) and an input variable control matrix g (x), thereby deriving specific parameters of the mathematical model of the Hamiltonian controlled system corresponding to the established virtual synchronous generator integrated into the infinite grid system, and finally checking zero state detectability of the established Hamiltonian controlled system according to the derived parameters to ensure that the Hamiltonian controlled system is at a balance point x 0 The position is asymptotically stable;
step S2.1 comprises:
first, an energy function is established:
h (x) is then applied to the state variables omega, delta, E q ' bias derivation, results such as
Shown;
referring to the generalized Hamiltonian controlled system model equation:
and incorporate dynamic model equation of infinite electric network system according to virtual synchronous machine builtAnd->Establishing a mathematical model of a Hamiltonian controlled system corresponding to the virtual synchronous machine integrated into an infinite power grid system:
wherein,gradients over time for state variables; j (x) is a system structure matrix, which is an antisymmetric matrix; r (x) is a system damping matrix which is a semi-positive definite symmetric matrix; u and y are conjugate variables representing input and output vectors, respectively; g (x) is an input vector control matrix, g T (x) Transpose the matrix thereof.
2. The method according to claim 1, wherein the step S2.2 of deriving specific parameters of the mathematical model of the built virtual synchronous generator incorporated in the corresponding hamilton controlled system of the infinite grid system comprises:
firstly, the built virtual synchronous machine is integrated into a Hamiltonian controlled system mathematical model corresponding to an infinite power grid systemAnd the established equation of the virtual synchronous machine incorporated into the dynamic model of an infinite grid system ∈>Obtaining a coefficient matrix:
since R (x) is a semi-positive definite symmetric matrix, satisfy R (x) =r T (x) Not less than 0, J (x) is an antisymmetric matrix, satisfying J (x) = -J T (x) And deriving a system damping matrix R (x), a system structure matrix J (x) and an input variable control matrix g (x) respectively as follows:
finally, an output equation is obtained:
the specific parameters of the Hamiltonian controlled system corresponding to the built virtual synchronous machine incorporated into the infinite power grid system are obtained through deduction;
to ensure that the established Hamiltonian controlled system is at the equilibrium point x 0 Is asymptotically stable, the established system must meet zero state detectability,obtaining the maximum invariable subset of the convergence of the Hamiltonian controlled system corresponding to the built virtual synchronous machine incorporated into the infinite power grid system, as +.>As shown, the invariant subset is the balance point of the system, thus satisfying zero state detectability.
3. The method according to claim 1, wherein step S3 specifically comprises:
first, according to the zero state detectability of the system, when the exciting voltage adjustment quantity u f Satisfy the following requirementsWhen K is positive definite matrix, the built virtual synchronous machine is integrated into Hamiltonian controlled system corresponding to infinite power grid system at balance point x 0 The position is asymptotically stable;
according to the established virtual synchronous machine, the system is integrated into a Hamiltonian controlled system corresponding to an infinite power grid system and the deduced parameters, and the exciting voltage regulating quantity u is obtained by back-pushing f ：
Wherein k is 1 And more than or equal to 0 is a positive feedback control proportional coefficient, and the exciting voltage regulating quantity u is obtained by utilizing reverse thrust f Establishing a complete control model of a virtual synchronous generator incorporated into an infinite grid system based on port energy remodeling, wherein the port is controlled by Hamiltonian feedback control u f The excitation link input end is connected with the virtual synchronous generator and used for inhibiting the virtual synchronous generator from being integrated into the oscillation of an infinite power grid system, wherein each parameter in the model is as shown in the formulaShown as X d And X d ' direct-axis steady-state reactance and direct-axis transient reactance of virtual synchronous generator, T respectively d0 ' is the direct axis transient short-circuit time constant, X of a virtual synchronous generator d∑ And X d∑ ' steady state equivalent reactance and transient equivalent reactance, respectively.
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