CN117614015A - Virtual synchronous generator control method and device - Google Patents
Virtual synchronous generator control method and device Download PDFInfo
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- CN117614015A CN117614015A CN202311657407.7A CN202311657407A CN117614015A CN 117614015 A CN117614015 A CN 117614015A CN 202311657407 A CN202311657407 A CN 202311657407A CN 117614015 A CN117614015 A CN 117614015A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/002—Flicker reduction, e.g. compensation of flicker introduced by non-linear load
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
- H02J3/241—The oscillation concerning frequency
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
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Abstract
The invention provides a virtual synchronous generator control method and device, and belongs to the technical field of virtual synchronous generator control. The method comprises the following steps: acquiring frequency parameters of the distributed power generation system in real time; detecting whether a distributed power generation system generates frequency disturbance according to the current frequency parameter; if the distributed power generation system generates frequency disturbance, determining moment of inertia and damping coefficient corresponding to the current frequency parameter, wherein the adjusting coefficients in the moment of inertia and the damping coefficient are proportionality coefficients; based on the rotational inertia and the damping coefficient, a virtual synchronous generator in the distributed power generation system is controlled by utilizing a preset self-adaptive control strategy. The invention can improve the accuracy of adjusting the moment of inertia, reduce the adjusting time and further rapidly improve the stability of the system.
Description
Technical Field
The present invention relates to the field of virtual synchronous generator control technologies, and in particular, to a virtual synchronous generator control method and device.
Background
In a traditional power system, the synchronous generator can provide inertia for a power grid, and the voltage and the power of the power grid can be effectively supported under the action of an excitation regulator and a rotor. Unlike the traditional power system with synchronous generator, the distributed power source with power electronic equipment has the advantages of flexible control, fast response speed, obvious defect, no moment of inertia of the power electronic converter and insufficient voltage and frequency supporting capacity of the power grid. The large-scale access of the distributed power supply ensures that the power system has the characteristics of obviously obtaining power electronization, and the transient characteristic and the dynamic characteristic are seriously affected.
The stability of the distributed power system can be effectively improved by introducing a virtual synchronous generator (virtual synchronous generator, VSG) for control, so that the distributed power system obtains enough frequency and voltage stability. The related control method of the virtual synchronous generator generally adopts an exponential type adjusting coefficient to adjust the rotational inertia, but the exponential type adjusting coefficient can enable the rotational inertia to be adjusted quickly, so that the rotational inertia is difficult to accurately adjust to a proper value, and the stability of a power system is difficult to quickly improve.
Disclosure of Invention
The embodiment of the invention provides a control method and a control device for a virtual synchronous generator, which are used for improving the accuracy of adjusting rotational inertia, reducing the adjusting time and further rapidly improving the stability of a system.
In a first aspect, an embodiment of the present invention provides a method for controlling a virtual synchronous generator, including:
acquiring frequency parameters of the distributed power generation system in real time;
detecting whether a distributed power generation system generates frequency disturbance according to the current frequency parameter;
if the distributed power generation system generates frequency disturbance, determining moment of inertia and damping coefficient corresponding to the current frequency parameter, wherein the adjusting coefficients in the moment of inertia and the damping coefficient are proportionality coefficients;
based on the rotational inertia and the damping coefficient, a virtual synchronous generator in the distributed power generation system is controlled by utilizing a preset self-adaptive control strategy.
In one possible implementation, after detecting whether a frequency disturbance occurs in the distributed power generation system according to the current frequency parameter, the method further includes:
if the distributed power generation system does not generate frequency disturbance, the moment of inertia and the damping coefficient are set to preset values.
In one possible implementation, the frequency parameters include frequency deviation and frequency change rate; the frequency deviation is the difference between the angular frequency output by the virtual synchronous generator and the power grid frequency, and the frequency change rate is the change rate of the angular frequency output by the virtual synchronous generator.
In one possible implementation, detecting whether a frequency disturbance occurs in the distributed power generation system according to the current frequency parameter includes:
judging whether the frequency change rate is larger than a change threshold value of the moment of inertia adjustment, whether the product of the frequency deviation and the frequency change rate is larger than 0, and whether the absolute value of the frequency deviation is larger than the change threshold value of the damping coefficient adjustment;
if the frequency change rate is greater than the change threshold value of the moment of inertia adjustment and the product of the frequency deviation and the frequency change rate is greater than 0, determining that frequency disturbance occurs;
or if the absolute value of the frequency deviation is larger than the change threshold value of the damping coefficient adjustment, determining that the frequency disturbance occurs.
In one possible implementation, the preset adaptive control strategy is determined by:
determining an active frequency control equation of the virtual synchronous generator according to the motion of the simulated rotor of the virtual synchronous generator;
determining a simulated rotor motion model of the virtual synchronous generator according to primary frequency modulation of the virtual synchronous generator;
and obtaining the self-adaptive control strategy of the virtual synchronous generator based on the active frequency control equation and the simulated rotor motion model.
In one possible implementation, determining the moment of inertia corresponding to the current frequency parameter includes:
according toDetermining the moment of inertia corresponding to the current frequency parameter;
wherein J represents moment of inertia corresponding to the current frequency parameter, J 0 Representing a predetermined moment of inertia, k j Represents the adjustment coefficient of the moment of inertia, ω represents the output frequency of the virtual synchronous generator, Δω represents the frequency deviation,represents the rate of change of frequency, C j Representing the threshold of change in moment of inertia adjustment.
In one possible implementation, determining the damping coefficient corresponding to the current frequency parameter includes:
according toDetermining a damping coefficient corresponding to the current frequency parameter;
wherein D represents a damping coefficient corresponding to the current frequency parameter, D 0 Representing a preset damping coefficient, k d Representing the adjustment coefficient of the damping coefficient, C d Representing the threshold of variation of the damping coefficient adjustment.
In one possible implementation, the adaptive control strategy is:
wherein J represents moment of inertia, ω, corresponding to the current frequency parameter 0 Representing the nominal angular frequency of the virtual synchronous generator,representing the rate of change of frequency, P, in a frequency parameter ref Representing a given active power, P, of a virtual synchronous generator e Represents the active power output by the virtual synchronous generator, D represents the damping coefficient corresponding to the current frequency parameter, and k ω1 Represents the difference coefficient, Δω represents the frequency deviation in the frequency parameter, δ represents the power angle, ++>Indicating the power angle change rate.
In a second aspect, an embodiment of the present invention provides a virtual synchronous generator control apparatus, including:
the acquisition module is used for acquiring the frequency parameters of the distributed power generation system in real time;
the detection module is used for detecting whether the distributed power generation system generates frequency disturbance according to the current frequency parameter;
the determining module is used for determining the moment of inertia and the damping coefficient corresponding to the current frequency parameter if the distributed power generation system generates frequency disturbance, wherein the adjusting coefficients in the moment of inertia and the damping coefficient are proportionality coefficients;
and the control module is used for controlling the virtual synchronous generator in the distributed power generation system by utilizing a preset self-adaptive control strategy based on the rotational inertia and the damping coefficient.
In one possible implementation, the determining module is further configured to:
if the distributed power generation system does not generate frequency disturbance, the moment of inertia and the damping coefficient are set to preset values.
Compared with the prior art, the embodiment of the invention has the beneficial effects that:
according to the embodiment of the invention, the adjustment coefficient of the moment of inertia during frequency disturbance is set as the proportionality coefficient, so that the attenuation rate of parameters in the moment of inertia can be reduced, the problem of too high adjustment speed of the moment of inertia caused by an exponential adjustment coefficient is avoided, the moment of inertia can be rapidly and accurately determined, the adjustment time is reduced, and the stability of a distributed power generation system is rapidly improved; based on the moment of inertia and the damping coefficient, the self-adaptive control strategy is utilized to cooperatively control the virtual synchronous generator, so that dynamic moment of inertia and the damping coefficient can be simultaneously provided for the virtual synchronous generator, the supporting capacity is improved, the control and adjustment only through the moment of inertia are avoided, the adjustable range of the distributed power generation system is enlarged, and the stability and reliability of the distributed power generation system are further improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments or the description of the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is an application scenario diagram of a virtual synchronous generator control method provided by an embodiment of the present invention;
FIG. 2 is a flowchart of a method for controlling a virtual synchronous generator according to an embodiment of the present invention;
fig. 3 is an equivalent circuit vector diagram of a virtual synchronous generator provided by an embodiment of the present invention;
FIG. 4 is a diagram of an active frequency control architecture provided by an embodiment of the present invention;
FIG. 5 is a control strategy diagram of a virtual synchronous generator control method provided by an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a virtual synchronous generator control device according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the following description will be made by way of specific embodiments with reference to the accompanying drawings.
Referring to an application scenario diagram of the virtual synchronous generator control method shown in fig. 1, a topology structure of a distributed power generation system is shown in fig. 1, and specifically, the distributed power generation system includes a distributed power generation module, an energy storage device, a DC/DC converter, a voltage source type three-phase bridge inverter circuit, and the like.
The control method of the distributed power generation system comprises power control, grid-connected and off-grid switching control, bidirectional energy storage control and the like, wherein the power control comprises active frequency control and reactive voltage control.
When the distributed power generation system has load disturbance, the overshoot of frequency and power can be effectively reduced, the adjustment time is shortened, and the stability of the distributed power generation system is further improved by the virtual synchronous generator control method provided by the embodiment of the invention. The virtual synchronous generator control method sequentially comprises the steps of power calculation, self-adaptive control strategy determination, voltage and current double closed-loop control, sinusoidal pulse width modulation (Sinusoidal Pulse Width Modulation, SPWM) and the like.
Specifically, the virtual synchronous generator control method simulates the characteristics of a rotor in a synchronous generator in active frequency control, introduces a primary frequency modulation control strategy in the synchronous generator into a control method of a distributed power generation system, and provides effective frequency support by adding adaptive control, thereby improving the stability of the distributed power generation system.
Fig. 2 is a flowchart of an implementation of a virtual synchronous generator control method according to an embodiment of the present invention, which is described in detail below:
step S201, frequency parameters of the distributed power generation system are acquired in real time.
In this embodiment, the frequency parameter of the distributed power generation system may be obtained by obtaining the grid frequency and the angular frequency output by the virtual synchronous generator. The grid frequency can adopt the angular frequency of the voltage at the public coupling point, and the angular frequency of the output of the virtual synchronous generator can be the angular frequency of the output voltage of the inverter.
Optionally, the frequency parameter includes a frequency deviation and a frequency change rate; the frequency deviation is the difference between the angular frequency output by the virtual synchronous generator and the power grid frequency, and the frequency change rate is the change rate of the angular frequency output by the virtual synchronous generator.
Step S202, detecting whether the distributed power generation system generates frequency disturbance according to the current frequency parameter.
Step S203, if the distributed power generation system generates frequency disturbance, determining a moment of inertia and a damping coefficient corresponding to the current frequency parameter, wherein adjustment coefficients in the moment of inertia and the damping coefficient are proportionality coefficients.
In this embodiment, when the frequency of the distributed power generation system is disturbed, the stability of the distributed power generation system is affected, and at this time, the stability of the system needs to be improved rapidly by adjusting the moment of inertia and the damping coefficient, so as to ensure the stable operation of the system. Therefore, it is necessary to determine whether the system is subject to frequency disturbance by using the frequency parameter to determine the corresponding moment of inertia and damping coefficient.
And setting the adjusting coefficients of the moment of inertia and the damping coefficients at the positions of the proportional coefficients, and reducing the attenuation rate of the parameters of the moment of inertia and the damping coefficients so as to improve the efficiency of determining the moment of inertia and the damping coefficients.
The rotational inertia and the damping coefficient each comprise an exponential parameter related to frequency, the adjustment coefficient is multiplied by the exponential parameter to serve as a proportional coefficient of the exponential parameter, and the adjustment rate of the exponential parameter is controlled to ensure the reasonability of the adjustment rate. Correspondingly, if the adjustment parameter is located at an exponential position in the exponential parameters, the adjustment speed of the moment of inertia and the damping coefficient is too fast, which is unfavorable for quickly and accurately determining the moment of inertia and the damping coefficient.
Step S204, based on the rotational inertia and the damping coefficient, the virtual synchronous generator in the distributed power generation system is controlled by utilizing a preset self-adaptive control strategy.
In the embodiment, the cooperative control is performed through the moment of inertia and the damping coefficient, wherein the effects of the damping coefficient in the dynamic process adjustment and steady state error reduction can be fully utilized, the control and adjustment through the moment of inertia only are avoided, and the adjustable range of the distributed power generation system is enlarged.
For example, when the load error deviation is large, the moment of inertia basically loses the control capability of frequency adjustment, and in this case, the stability of the system frequency can be effectively restored through the adjustment of the damping coefficient.
According to the embodiment of the invention, the adjustment coefficient of the moment of inertia during frequency disturbance is set as the proportionality coefficient, so that the attenuation rate of parameters in the moment of inertia can be reduced, the problem of too high adjustment speed of the moment of inertia caused by an exponential adjustment coefficient is avoided, the moment of inertia can be rapidly and accurately determined, the adjustment time is reduced, and the stability of a distributed power generation system is rapidly improved; based on the moment of inertia and the damping coefficient, the self-adaptive control strategy is utilized to cooperatively control the virtual synchronous generator, so that dynamic moment of inertia and the damping coefficient can be simultaneously provided for the virtual synchronous generator, the supporting capacity is improved, the control and adjustment only through the moment of inertia are avoided, the adjustable range of the distributed power generation system is enlarged, and the stability and reliability of the distributed power generation system are further improved.
Optionally, step S202 detects whether a frequency disturbance occurs in the distributed power generation system according to the current frequency parameter, which may be described in detail as follows:
judging whether the frequency change rate is larger than a change threshold value of the moment of inertia adjustment, whether the product of the frequency deviation and the frequency change rate is larger than 0, and whether the absolute value of the frequency deviation is larger than the change threshold value of the damping coefficient adjustment;
if the frequency change rate is greater than the change threshold value of the moment of inertia adjustment and the product of the frequency deviation and the frequency change rate is greater than 0, determining that frequency disturbance occurs;
or if the absolute value of the frequency deviation is larger than the change threshold value of the damping coefficient adjustment, determining that the frequency disturbance occurs.
In this embodiment, the frequency parameter is determined by setting two change thresholds, that is, the corresponding frequency parameter is determined by the change threshold of the moment of inertia adjustment and the change threshold of the damping coefficient adjustment, so as to determine whether the change of the frequency parameter belongs to micro fluctuation or frequency disturbance occurs, and further determine whether the moment of inertia and the damping coefficient need to be adjusted.
And the adjustment of the moment of inertia is further determined by judging whether the product of the frequency deviation and the frequency change rate is greater than zero, namely whether the moment of inertia needs to be adjusted is determined by determining the positive and negative of the product of the frequency deviation and the frequency change rate.
Specifically, for the moment of inertia, the change threshold of moment of inertia adjustment is greater than zero, and when the frequency change rate is greater than the change threshold of moment of inertia adjustment, it is indicated that the change rate of the angular frequency of the output of the virtual synchronous generator exceeds the corresponding change threshold, i.e. frequency disturbance may occur in the system; meanwhile, the product of the frequency deviation and the frequency change rate is larger than zero, which means that the difference between the angular frequency output by the virtual synchronous generator and the power grid frequency is larger than zero, and the change rate of the angular frequency output by the virtual synchronous generator is larger than zero, namely the rotational inertia needs to be adjusted, so that the stability of the system is improved.
If the frequency change rate is not greater than the change threshold of the moment of inertia adjustment, it is indicated that the change rate of the angular frequency of the output of the virtual synchronous generator is relatively small, and the corresponding moment of inertia does not need to be adjusted, so that minor fluctuation may occur in the system. The generated tiny fluctuation can be filtered through the change threshold value of the rotational inertia adjustment, so that the failure of the judgment value due to the positive and negative judgment disorder is avoided, and the stable operation of the system is ensured.
If the product of the frequency deviation and the frequency change rate is not greater than zero, the difference value between the angular frequency output by the virtual synchronous generator and the power grid frequency is greater than zero, and the change rate of the angular frequency output by the virtual synchronous generator is not greater than zero; alternatively, the difference between the angular frequency of the output of the virtual synchronous generator and the grid frequency is not greater than zero, and the rate of change of the angular frequency of the output of the virtual synchronous generator is greater than zero. I.e. the frequency change rate in the frequency parameter is stable or the direction of change of the frequency change rate is changed towards the stable operation of the system, no adjustment of the moment of inertia is necessary either.
For the damping coefficient, if the absolute value of the frequency deviation is larger than the change threshold value of the damping coefficient adjustment, the difference value of the angular frequency output by the virtual synchronous generator and the power grid frequency is larger than the change threshold value of the damping coefficient adjustment, namely, larger deviation exists between the angular frequency output by the virtual synchronous generator and the power grid frequency, frequency disturbance occurs in the system, and the damping coefficient needs to be adjusted; if the absolute value of the frequency deviation is not greater than the change threshold value of the damping coefficient adjustment, the difference value between the angular frequency output by the virtual synchronous generator and the power grid frequency is smaller, and the corresponding damping coefficient does not need to be adjusted.
In addition, if the frequency change rate is not greater than the change threshold of the moment of inertia adjustment and the absolute value of the frequency deviation is not greater than the change threshold of the damping coefficient adjustment, it is indicated that the change rate of the angular frequency of the output of the virtual synchronous generator is relatively small, and the angular frequency of the output of the virtual synchronous generator and the power grid frequency are relatively close, i.e. the system is in a stable running state. If the product of the frequency deviation and the frequency change rate is not greater than zero, and the absolute value of the frequency deviation is not greater than the change threshold value of the damping coefficient adjustment, it is indicated that the angular frequency and the grid frequency of the output of the virtual synchronous generator are also relatively close, and the change direction of the frequency change rate is changed towards the direction of stable operation of the system, that is, the system is in a stable operation state, small fluctuation may exist, but the system is not disturbed by the frequency.
Optionally, the determining the moment of inertia corresponding to the current frequency parameter in step S203 may be described in detail as:
according toDetermining the moment of inertia corresponding to the current frequency parameter;
wherein J represents moment of inertia corresponding to the current frequency parameter, J 0 Representing a predetermined moment of inertia, k j Represents the adjustment coefficient of the moment of inertia, ω represents the output frequency of the virtual synchronous generator, Δω represents the frequency deviation,represents the rate of change of frequency, C j Representing the threshold of change in moment of inertia adjustment.
Step S203 determines a damping coefficient corresponding to the current frequency parameter, which may be described in detail as follows:
according toDetermining a damping coefficient corresponding to the current frequency parameter;
wherein D represents a damping coefficient corresponding to the current frequency parameter, D 0 Representing a preset damping coefficient, k d Representing the adjustment coefficient of the damping coefficient, C d Representing the threshold of variation of the damping coefficient adjustment.
The preset rotational inertia and the preset damping coefficient are the rotational inertia and the damping coefficient of the virtual synchronous generator when the distributed power generation system runs in a steady state.
After detecting whether the distributed power generation system has a frequency disturbance according to the current frequency parameter in step S202, the method further includes:
if the distributed power generation system does not generate frequency disturbance, the moment of inertia and the damping coefficient are set to preset values.
In this embodiment, the frequency of the distributed power generation system may also slightly fluctuate under the condition of steady operation, but the distributed power generation system can still operate stably because the fluctuation is small and the distributed power generation system is not greatly affected.
Exemplary, if the distributed power generation system is not experiencing frequency disturbancesI.e. the system is in steady state operation, the adaptive control strategy can directly employ smaller moment of inertia and damping coefficient, i.e. J 0 And D 0 To ensure that the system maintains steady state operation.
In one possible implementation, referring to the equivalent circuit vector diagram of the virtual synchronous generator shown in fig. 3, it can be known that the active power output by the virtual synchronous generator is:
the reactive power is:
wherein P is e Represents active power, Q e Representing reactive power, U g Represents the grid voltage, Z represents the equivalent impedance, z=r+jωl=r+jx, E the electromotive force of the virtual synchronous generator, δ represents the power angle, θ represents the impedance angle,in an actual distributed power generation system, the resistance R in the equivalent impedance Z is generally much smaller than the reactance X, where the reactance satisfies x=ωl, so the actual value of θ is approximately 90 degrees, and at the same time, the power angle is small, and accordingly, the active power and the reactive power can be simplified as:
based on this, active frequency control is performed on the virtual synchronous generator control, and accordingly, an adaptive control strategy in the active frequency control needs to be determined.
Optionally, the adaptive control strategy preset in step S204 may be determined by:
determining an active frequency control equation of the virtual synchronous generator according to the motion of the simulated rotor of the virtual synchronous generator;
determining a simulated rotor motion model of the virtual synchronous generator according to primary frequency modulation of the virtual synchronous generator;
and obtaining the self-adaptive control strategy of the virtual synchronous generator based on the active frequency control equation and the simulated rotor motion model.
In this embodiment, by referring to the motion equation of the rotor of the synchronous generator, virtual inertia may be introduced, and the motion of the simulated rotor of the virtual synchronous generator may be obtained correspondingly, so as to obtain an active frequency control equation of the virtual synchronous generator, which may specifically be:
wherein J represents the moment of inertia, ω, of the virtual synchronous generator 0 Represents the rated angular frequency of the virtual synchronous generator, ω represents the angular frequency of the output voltage of the virtual synchronous generator, i.e. the output angular frequency, ω g The angular frequency, i.e. the grid frequency,frequency change rate, P, representing angular frequency of output voltage of virtual synchronous generator m Representing input mechanical power of a virtual synchronous generator, P e The active power of the output of the virtual synchronous generator is represented, and D represents the damping coefficient of the virtual synchronous generator.
Correspondingly, the power angle satisfies:
in the method, in the process of the invention,representing the rate of change of the power angle, delta 1 Representing the phase, delta, of the electromotive force of a virtual synchronous generator 2 Representing common couplingThe phase of the voltage at the point Δω represents the frequency deviation, i.e. the difference between the output angular frequency of the virtual synchronous generator and the grid frequency.
Referring to the primary frequency modulation of the traditional synchronous generator, determining the primary frequency modulation of the virtual synchronous generator, and obtaining a simulated rotor motion model of the virtual synchronous generator, wherein the simulated rotor motion model specifically comprises the following steps:
P m ＝P ref -P f1 ＝P ref -k ω1 (ω g -ω 0 )；
wherein P is ref Representing a given active power, P, of a virtual synchronous generator f1 Representing the active adjustment quantity, k, of primary frequency modulation ω1 Representing the difference coefficient.
Based on an active frequency control equation and a simulated rotor motion model, a corresponding self-adaptive control strategy can be obtained, which can be specifically:
wherein J represents moment of inertia, ω, corresponding to the current frequency parameter 0 Representing the nominal angular frequency of the virtual synchronous generator,representing the rate of change of frequency, P, in a frequency parameter ref Representing a given active power, P, of a virtual synchronous generator e Represents the active power output by the virtual synchronous generator, D represents the damping coefficient corresponding to the current frequency parameter, and k ω1 Represents the difference coefficient, Δω represents the frequency deviation in the frequency parameter, δ represents the power angle, ++>Indicating the power angle change rate.
Referring to the active frequency control structure diagram shown in fig. 4, based on the obtained adaptive control strategy, active frequency control is performed on the virtual synchronous generator by adjusting the moment of inertia, the damping coefficient and the tuning difference parameter, as shown in fig. 4Representing an integration operator.
In a specific embodiment, referring to the control strategy diagram of the virtual synchronous generator control method shown in fig. 5, when the virtual synchronous generator is controlled by a preset adaptive control strategy, the corresponding moment of inertia and damping coefficient are determined by the frequency deviation and the frequency change rate, so that the virtual synchronous generator is controlled based on the determined moment of inertia, damping coefficient and tuning difference parameter, and the distributed power generation system maintains steady-state operation or improves the stability of the system rapidly.
According to the embodiment of the invention, the adjustment coefficient of the moment of inertia during frequency disturbance is set as the proportionality coefficient, so that the attenuation rate of parameters in the moment of inertia can be reduced, the problem of too high adjustment speed of the moment of inertia caused by an exponential adjustment coefficient is avoided, the moment of inertia can be rapidly and accurately determined, the adjustment time is reduced, and the stability of a distributed power generation system is rapidly improved; setting a calculation formula of a damping coefficient correspondingly, and setting an adjusting coefficient of the damping coefficient as a proportional coefficient so as to carry out cooperative control through the rotational inertia and the damping coefficient; the method has the advantages that whether the distributed power generation system is subjected to frequency interference is particularly judged, corresponding rotational inertia and damping coefficient are selected, the calculation stages of the rotational inertia and the damping coefficient are divided based on smaller rotational inertia and damping coefficient when the system runs stably, simplicity and definition of segmentation are guaranteed, rapid classification and calculation are facilitated, and control efficiency is improved; based on the moment of inertia and the damping coefficient, the self-adaptive control strategy is utilized to cooperatively control the virtual synchronous generator, so that dynamic moment of inertia and the damping coefficient can be simultaneously provided for the virtual synchronous generator, the supporting capacity is improved, the control and adjustment only through the moment of inertia are avoided, the adjustable range of the distributed power generation system is enlarged, and the stability and reliability of the distributed power generation system are further improved.
It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not limit the implementation process of the embodiment of the present invention.
The following are device embodiments of the invention, for details not described in detail therein, reference may be made to the corresponding method embodiments described above.
Fig. 6 shows a schematic structural diagram of a virtual synchronous generator control device according to an embodiment of the present invention, and for convenience of explanation, only the portions related to the embodiment of the present invention are shown, which is described in detail below:
as shown in fig. 6, the virtual synchronous generator control apparatus 60 includes:
an acquisition module 61, configured to acquire a frequency parameter of the distributed power generation system in real time;
the detection module 62 is configured to detect whether a frequency disturbance occurs in the distributed power generation system according to the current frequency parameter;
the determining module 63 is configured to determine a moment of inertia and a damping coefficient corresponding to a current frequency parameter if the distributed power generation system generates a frequency disturbance, where adjustment coefficients in the moment of inertia and the damping coefficient are both proportional coefficients;
the control module 64 is configured to control the virtual synchronous generator in the distributed power generation system based on the rotational inertia and the damping coefficient by using a preset adaptive control strategy.
In one possible implementation, the determining module 63 is further configured to:
if the distributed power generation system does not generate frequency disturbance, the moment of inertia and the damping coefficient are set to preset values.
In one possible implementation, the frequency parameters include frequency deviation and frequency change rate; the frequency deviation is the difference between the angular frequency output by the virtual synchronous generator and the power grid frequency, and the frequency change rate is the change rate of the angular frequency output by the virtual synchronous generator.
In one possible implementation, the detection module 62 is specifically configured to:
judging whether the frequency change rate is larger than a change threshold value of the moment of inertia adjustment, whether the product of the frequency deviation and the frequency change rate is larger than 0, and whether the absolute value of the frequency deviation is larger than the change threshold value of the damping coefficient adjustment;
if the frequency change rate is greater than the change threshold value of the moment of inertia adjustment and the product of the frequency deviation and the frequency change rate is greater than 0, determining that frequency disturbance occurs;
or if the absolute value of the frequency deviation is larger than the change threshold value of the damping coefficient adjustment, determining that the frequency disturbance occurs.
In one possible implementation, the control module 64 is further configured to:
determining an active frequency control equation of the virtual synchronous generator according to the motion of the simulated rotor of the virtual synchronous generator;
determining a simulated rotor motion model of the virtual synchronous generator according to primary frequency modulation of the virtual synchronous generator;
and obtaining the self-adaptive control strategy of the virtual synchronous generator based on the active frequency control equation and the simulated rotor motion model.
In one possible implementation, the determining module 63 is specifically configured to:
according toDetermining the moment of inertia corresponding to the current frequency parameter;
wherein J represents moment of inertia corresponding to the current frequency parameter, J 0 Representing a predetermined moment of inertia, k j Represents the adjustment coefficient of the moment of inertia, ω represents the output frequency of the virtual synchronous generator, Δω represents the frequency deviation,represents the rate of change of frequency, C j Representing the threshold of change in moment of inertia adjustment.
In one possible implementation, the determining module 63 is specifically configured to:
according toDetermining a damping coefficient corresponding to the current frequency parameter;
wherein D represents a damping coefficient corresponding to the current frequency parameter, D 0 Representing a preset damping coefficient, k d Representing the adjustment coefficient of the damping coefficient, C d Representing the threshold of variation of the damping coefficient adjustment.
In one possible implementation, the control module 64 is specifically configured to:
wherein J represents moment of inertia, ω, corresponding to the current frequency parameter 0 Representing the nominal angular frequency of the virtual synchronous generator,representing the rate of change of frequency, P, in a frequency parameter ref Representing a given active power, P, of a virtual synchronous generator e Represents the active power output by the virtual synchronous generator, D represents the damping coefficient corresponding to the current frequency parameter, and k ω1 Represents the difference coefficient, Δω represents the frequency deviation in the frequency parameter, δ represents the power angle, ++>Indicating the power angle change rate.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The integrated modules/units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the present invention may implement all or part of the flow of the method of the above embodiment, or may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the steps of each method embodiment described above may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, executable files or in some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth.
The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and are intended to be included in the scope of the present invention.
Claims (10)
1. A virtual synchronous generator control method, characterized by comprising:
acquiring frequency parameters of the distributed power generation system in real time;
detecting whether the distributed power generation system generates frequency disturbance according to the current frequency parameter;
if the distributed power generation system generates frequency disturbance, determining moment of inertia and damping coefficients corresponding to the current frequency parameter, wherein the adjustment coefficients in the moment of inertia and the damping coefficients are proportionality coefficients;
and based on the rotational inertia and the damping coefficient, controlling the virtual synchronous generator in the distributed power generation system by utilizing a preset self-adaptive control strategy.
2. The virtual synchronous generator control method according to claim 1, further comprising, after the detecting whether the distributed power generation system has a frequency disturbance according to the current frequency parameter:
and if the distributed power generation system does not generate frequency disturbance, setting the moment of inertia and the damping coefficient to preset values.
3. The virtual synchronous generator control method of claim 1, wherein the frequency parameter comprises a frequency deviation and a frequency change rate; the frequency deviation is the difference value between the angular frequency output by the virtual synchronous generator and the power grid frequency, and the frequency change rate is the change rate of the angular frequency output by the virtual synchronous generator.
4. A virtual synchronous generator control method as set forth in claim 3, wherein the detecting whether the distributed power generation system is frequency perturbed based on the current frequency parameter comprises:
judging whether the frequency change rate is larger than a change threshold value of rotational inertia adjustment, whether the product of the frequency deviation and the frequency change rate is larger than 0, and whether the absolute value of the frequency deviation is larger than a change threshold value of damping coefficient adjustment;
if the frequency change rate is larger than a change threshold value of moment of inertia adjustment and the product of the frequency deviation and the frequency change rate is larger than 0, determining that frequency disturbance occurs;
or if the absolute value of the frequency deviation is larger than the change threshold value of the damping coefficient adjustment, determining that the frequency disturbance occurs.
5. The virtual synchronous generator control method according to claim 1, wherein the preset adaptive control strategy is determined by:
determining an active frequency control equation of the virtual synchronous generator according to the motion of the simulated rotor of the virtual synchronous generator;
determining a simulated rotor motion model of the virtual synchronous generator according to primary frequency modulation of the virtual synchronous generator;
and obtaining the self-adaptive control strategy of the virtual synchronous generator based on the active frequency control equation and the simulated rotor motion model.
6. The method of claim 4, wherein determining the moment of inertia corresponding to the current frequency parameter comprises:
according toDetermining the moment of inertia corresponding to the current frequency parameter;
wherein J represents moment of inertia corresponding to the current frequency parameter, J 0 Representing a predetermined moment of inertia, k j Represents the adjustment coefficient of the moment of inertia, ω represents the output frequency of the virtual synchronous generator, Δω represents the frequency deviation,representing the rate of change of the frequency, C j Representing the threshold of change in moment of inertia adjustment.
7. The method of claim 4, wherein determining a damping coefficient corresponding to the current frequency parameter comprises:
according toDetermining a damping coefficient corresponding to the current frequency parameter;
wherein D represents a damping coefficient corresponding to the current frequency parameter, D 0 Representing a preset damping coefficient, k d Representing the adjustment coefficient of the damping coefficient, C d Representing the threshold of variation of the damping coefficient adjustment.
8. The virtual synchronous generator control method of any one of claims 5-7, wherein the adaptive control strategy is:
wherein J represents moment of inertia, ω, corresponding to the current frequency parameter 0 Representing the nominal angular frequency of the virtual synchronous generator,representing the rate of change of frequency, P, in said frequency parameter ref Representing a given active power, P, of said virtual synchronous generator e Representing the active power output by the virtual synchronous generator, D represents the damping coefficient corresponding to the current frequency parameter, and k ω1 Represents the difference coefficient, Δω represents the frequency deviation in the frequency parameter, δ represents the power angle, +.>Indicating the power angle change rate.
9. A virtual synchronous generator control apparatus, comprising:
the acquisition module is used for acquiring the frequency parameters of the distributed power generation system in real time;
the detection module is used for detecting whether the distributed power generation system generates frequency disturbance according to the current frequency parameter;
the determining module is used for determining the moment of inertia and the damping coefficient corresponding to the current frequency parameter if the distributed power generation system generates frequency disturbance, wherein the adjusting coefficients in the moment of inertia and the damping coefficient are proportionality coefficients;
and the control module is used for controlling the virtual synchronous generator in the distributed power generation system by utilizing a preset self-adaptive control strategy based on the rotational inertia and the damping coefficient.
10. The virtual synchronous generator control device of claim 9, wherein the determination module is further configured to:
and if the distributed power generation system does not generate frequency disturbance, setting the moment of inertia and the damping coefficient to preset values.
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