CN112003267A - Broadband harmonic resonance coordinated damping robust current control method and device - Google Patents

Broadband harmonic resonance coordinated damping robust current control method and device Download PDF

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CN112003267A
CN112003267A CN202010721339.6A CN202010721339A CN112003267A CN 112003267 A CN112003267 A CN 112003267A CN 202010721339 A CN202010721339 A CN 202010721339A CN 112003267 A CN112003267 A CN 112003267A
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current
damping
phase
obtaining
grid
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CN112003267B (en
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陈智勇
龙宏涛
胡毕华
肖军
邓文浪
谭平安
盘宏斌
易灵芝
陈才学
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Xiangtan University
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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
    • 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
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • 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
    • 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
    • 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
    • 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]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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  • Feedback Control In General (AREA)

Abstract

The invention discloses a broadband harmonic resonance coordinated damping robust current control method and a device, wherein the method comprises the following steps: the method comprises the following steps: s100, collecting three-phase damping current and three-phase grid-connected current, obtaining damping current reference according to harmonic components of the grid-connected current, and further obtaining a tracking error signal of the damping current; s200, obtaining a real-time value of a sliding mode surface function according to the tracking error signal, dynamically updating a switching gain observation value based on a self-adaptive law model, and obtaining an output control signal based on a perturbation parameter control law model; and S300, modulating the output control signal through a three-phase pulse width modulation module, outputting six paths of driving pulses, and driving the grid of the IGBT of the active damping inversion component. The invention ensures the gradual stability of the control system, reduces buffeting of control input signals and improves the robustness of the control system, thereby enabling the coordinated damper to efficiently manage broadband harmonic resonance.

Description

Broadband harmonic resonance coordinated damping robust current control method and device
Technical Field
The invention relates to an intelligent power distribution system, in particular to a broadband harmonic resonance coordinated damping robust current control method and device.
Background
Renewable energy power generation systems (e.g., large micro-grids, wind farms, photovoltaic power plants) have a large number of power electronic interface devices. On one hand, broadband impedance coupling exists between the broadband resonant; on the other hand, when broadband and higher harmonic currents emitted by the power electronic interface equipment are transmitted on a long-distance medium-high voltage transmission line, the characteristic subharmonic currents can also exceed the standard due to the influence of distribution parameters of the transmission line.
In the prior art, a coordinated damper is usually installed on a low-voltage and medium-voltage grid-connected side, so that broadband impedance isolation between a renewable energy power generation system and a power distribution network is realized, and potential broadband harmonic resonance is effectively damped. However, the "precondition" of the coordinated damper for effectively controlling the broadband harmonic resonance is that: 1) the harmonic component of the grid-connected current must be accurately extracted; 2) the active damping inversion output phase voltage must stably, accurately and quickly track the grid-connected harmonic current. Therefore, the premise of ensuring the harmonic damper to effectively treat the broadband harmonic resonance becomes a problem.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a control method for broadband harmonic resonance coordinated damping robust current, which can improve the capability of a coordinated damping inversion control system for tracking grid-connected harmonic current, and further realize the efficient treatment of broadband harmonic resonance by a coordinated damper.
The invention also provides a broadband harmonic resonance coordinated damping robust current control device with the broadband harmonic resonance coordinated damping robust current control method.
The broadband harmonic resonance coordinated damping robust current control method comprises the following steps: s100, collecting three-phase damping current and three-phase grid-connected current, obtaining damping current reference according to harmonic components of the grid-connected current, and further obtaining a tracking error signal of the damping current; s200, obtaining a real-time value of a sliding mode surface function according to the tracking error signal, dynamically updating a switching gain observation value based on a self-adaptive law model, and obtaining an output control signal based on a perturbation parameter control law model; and S300, modulating the signal through a three-phase pulse width modulation module according to the output control signal, outputting six paths of driving pulses, and driving the grid of the IGBT of the active damping inversion component.
The broadband harmonic resonance coordinated damping robust current control method provided by the embodiment of the invention at least has the following beneficial effects: the control signal is obtained by acquiring the damping current and the grid-connected current and constructing a model, so that the gradual stability of the system is ensured, the buffeting of the control input signal is reduced, and the robustness of the control system is improved, so that the coordinated damper can efficiently manage the broadband harmonic resonance.
According to some embodiments of the invention, said step S100 comprises: s110, collecting three-phase damping current and three-phase grid-connected current through a Hall current sensor; s120, extracting harmonic component i of the grid-connected currentghAccording to the active damping proportionality coefficient KADeriving the damping current reference id_ref(ii) a S130, according to the damping current and the damping current reference id_refAnd obtaining the tracking error signal e, wherein the calculation method of the tracking error signal e is as follows: e ═ id–id_refWherein idAnd id_refSaid damping representing the same phase respectivelyA current and the damping current reference.
According to some embodiments of the invention, the damping current is referenced tod_refThe obtaining method comprises the following steps: i.e. id_ref＝-KAighIn which K isARepresenting the active damping proportionality coefficient, ighRepresents a harmonic component of the grid-tied current in phase with the damping current.
According to some embodiments of the invention, the sliding-mode surface function comprises:
Figure BDA0002600127810000021
wherein s represents the sliding mode surface function, e represents the tracking error signal, kpIs a proportionality coefficient, kiT represents time as an integral coefficient.
According to some embodiments of the invention, the method of deriving the switching gain observation based on the adaptive law model comprises: obtaining a derivative of the switching gain observation value according to the adaptive law model, wherein the adaptive law model is as follows:
Figure BDA0002600127810000022
wherein the content of the first and second substances,
Figure BDA0002600127810000023
representing switching gain observations
Figure BDA0002600127810000024
S represents the sliding mode surface function; gamma represents an adaptive coefficient and is a normal number; derivative of the switching gain observations
Figure BDA0002600127810000025
Integrating to obtain the switching gain observed value
Figure BDA0002600127810000026
According to some embodiments of the invention, the perturbed parametric control law model comprises:
Figure BDA0002600127810000031
wherein u is an output control signal,
Figure BDA0002600127810000032
and
Figure BDA0002600127810000033
respectively represent h1And h2An estimated value of (A), and
Figure BDA0002600127810000034
Figure BDA0002600127810000035
kprepresents the proportionality coefficient, idIs representative of the damping current(s),
Figure BDA0002600127810000036
representing the damping current reference id_refDerivative of, LfRepresenting active damping inverter filter inductance, RfRepresents LfEquivalent resistance of, KctRepresenting the transformation ratio coefficient of the coupling transformer, sgn () representing the sign function, kiRepresenting an integral coefficient, s representing the sliding mode surface function,
Figure BDA0002600127810000037
representing the switching gain observation, e representing the tracking error signal.
In accordance with some embodiments of the present invention,
Figure BDA0002600127810000038
and
Figure BDA0002600127810000039
respectively taking active damping inversion filter inductance LfAnd RfA nominal value of (1), wherein RfRepresents LfThe equivalent resistance of (c).
The broadband harmonic resonance coordinated damping robust current control device comprises the following components: the error signal tracking module is used for acquiring three-phase damping current and three-phase grid-connected current, obtaining damping current reference according to harmonic component of the grid-connected current and further obtaining a tracking error signal of the damping current; the control signal processing module is used for obtaining a real-time value of the sliding mode surface function according to the tracking error signal, dynamically updating a switching gain observation value based on a self-adaptive law model, and obtaining an output control signal based on a perturbation parameter control law model; and the three-phase pulse width modulation module is used for modulating the output control signal, outputting six paths of driving pulses and driving the grid of the IGBT of the active damping inversion component.
The broadband harmonic resonance coordinated damping robust current control device provided by the embodiment of the invention at least has the following beneficial effects: the control signal is obtained by acquiring the damping current and the grid-connected current and constructing a model, so that the gradual stability of the system is ensured, the buffeting of the control input signal is reduced, and the robustness of the control system is improved, so that the coordinated damper can efficiently manage the broadband harmonic resonance.
According to some embodiments of the invention, the control signal processing module comprises three single-phase control submodules for obtaining the output control signals of three phases, respectively, comprising: the sliding mode surface module is used for obtaining a real-time value of a sliding mode surface function according to the tracking error signal; the switching gain self-adaptive module is used for dynamically updating the switching gain observation value based on the self-adaptive law model according to the real-time value of the sliding mode surface function; and the tracking switching module is used for obtaining the output control signal based on the perturbed parameter control law model according to the damping current, the damping current reference, the tracking error signal, the real-time value of the sliding mode surface function and the switching gain observation value.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
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The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic illustration of a flow of steps of a method according to an embodiment of the present invention;
FIG. 2 is a coordinated damper main circuit topology;
FIG. 3 is a single-phase main circuit topology of the coordinated damper;
FIG. 4 is a simplified topology of a single-phase main circuit of the coordinated damper;
FIG. 5 is a single phase equivalent circuit of the tuned damper in the harmonic frequency domain;
FIG. 6 is an amplitude-frequency response curve of a passive damper;
FIG. 7 is a power frequency characteristic of a broadband harmonic resonance damping mechanism of the coordinated damper;
FIG. 8 is a harmonic characteristic of a broadband harmonic resonance damping mechanism of a tuned damper;
FIG. 9 is a schematic diagram of the coordinated damping robust current control including the main circuit in the method according to the embodiment of the present invention;
FIG. 10 is a schematic diagram of a coordinated damping robust three-phase current control method corresponding to FIG. 9;
FIG. 11 shows an example of the harmonic current source i of phase A when the harmonic frequency is suddenly changeds,aThe simulated waveform of (2);
FIG. 12 shows the A-phase grid-connected current i corresponding to FIG. 11g,aThe simulated waveform of (2);
FIG. 13 is a diagram illustrating the trajectory of the motion state of the error and the error integral of the controlled system before the abrupt change of the harmonic frequency in the method according to the embodiment of the present invention;
FIG. 14 is a diagram illustrating the trajectory of the motion state of the error and the error integral of the controlled system after the abrupt change of the harmonic frequency in the method according to the embodiment of the present invention;
FIG. 15 shows an example of an A-phase harmonic current source i during a sudden increase in harmonic amplitudes,aThe simulated waveform of (2);
FIG. 16 is the A-phase grid-connected current i corresponding to FIG. 15g,aThe simulated waveform of (2);
FIG. 17 is a block diagram of an apparatus according to an embodiment of the invention.
Reference numerals:
the system comprises an error signal tracking module 100, a control signal processing module 200 and a three-phase pulse width modulation module 300;
a single-phase control sub-module 210, a sliding mode surface module 211, a switching gain adaptation module 212, and a tracking switching module 213.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and more than, less than, more than, etc. are understood as excluding the present number, and more than, less than, etc. are understood as including the present number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.
The noun explains:
an Insulated Gate Bipolar Transistor (IGBT) is a composite fully-controlled voltage-driven power semiconductor device consisting of a Bipolar Junction Transistor (BJT) and an insulated Gate field effect transistor (MOS), and has the advantages of high input impedance of the MOSFET and low conduction voltage drop of the GTR.
Referring to fig. 1, a method of an embodiment of the invention includes: s100, collecting three-phase damping current and three-phase grid-connected current, obtaining damping current reference according to harmonic components of the grid-connected current, and further obtaining a tracking error signal of the damping current; s200, obtaining a real-time value of the sliding mode surface function according to the tracking error signal, obtaining a switching gain observation value based on a self-adaptive law model, and obtaining an output control signal based on a perturbation parameter control law model; and S300, modulating the output control signal through the three-phase pulse width modulation module, outputting six paths of driving pulses, and driving the grid of the IGBT of the active damping inversion component.
The damping current is an input current obtained by modulating the sine pulse width by an active damping three-phase bridge inverter and shaping the current waveform by a filter, wherein the damping current is output current of an active damping inversion component in a coordinated damper.
The coordinated damper main circuit topology, as shown in fig. 2, includes: passive attenuator, active attenuator and coupling transformer. In fig. 2, subscripts a, b, c denote a-phase, b-phase, c-phase of the three-phase electric signal; i isdTo coordinate the output current of the damper; u shapepcThe phase voltage borne by the active damper; l isfIs an active damping inversion filter inductor. Passive damper consists of inductor Lp(16.9mH) and a capacitor Cp(600 muF) are connected in parallel; the parallel resonance occurs at the fundamental frequency of 50Hz, and the impedance of the fundamental frequency is maximum; at this time, the branch where the passive damper is located can be regarded as an open circuit; as the frequency increases, the harmonic impedance is greatly attenuated and the branch can effectively bypass the harmonic current. The active damper is composed of a rectifying component and an inverting component; the diode uncontrollable rectifying component provides stable direct current voltage for the inverter component through the filter capacitor; the inverter component is controlled to emit harmonic current with specified frequency and size, so that impedance isolation between a harmonic pollution source and a power grid can be realized, and a harmonic resonance damping effect is realized. Coupling transformer (transformation ratio K)ct1) an active damper and a passive damper are connected in series; at fundamental frequency, the equivalent impedance of a passive damper is very large (parallel resonance occurs at 50 Hz) compared to an active damper; by the series voltage division, the active damper is subjected to only a small fundamental voltage, which ensures that the power switch is free from being subjected to overvoltage.
To explain the working principle of the coordinated damper, first of all, the following is givenIts single-phase main circuit topology is shown with reference to fig. 3. In FIG. 3, harmonic current source I is usedsRepresenting a broadband harmonic pollution source; representing an infinite network by a Thevenin equivalent circuit, comprising a voltage source UgEquivalent impedance Zg(ii) a I for current (grid-connected current) flowing from broadband harmonic pollution source into infinite power gridgRepresents; because the active damping inverter part adopts a voltage source PWM strategy (PWM is abbreviated as Pulse width modulation), the active damper can be regarded as an output filter inductor LfSeries voltage source UfWherein U isfAnd outputting phase voltage for active damping inversion.
Further, the active damping is inverted to the filter inductor LfAnd a series voltage source UfAnd converting to the primary side of the coupling transformer to obtain a single-phase main circuit simplified topology of the coordinated damper, which is shown in figure 4. In FIG. 4, ZpdIs a passive damper equivalent impedance, and Zpd＝jωLp+1/(jωCp)；ZLfIs an active damping inverter filter impedance, and ZLf＝jωLf+RfWherein R isfIs a filter inductor Lfω is the system frequency. ZppTo coordinate the total impedance of the damper branch, an
Figure BDA0002600127810000071
Controlling active damping inverter output phase voltage Uf＝-KAIghIn which K isAIs an active damping proportionality coefficient, IghThe active damper is equivalent to a harmonic virtual impedance Z connected in series at the grid-connected side for harmonic component of grid-connected currentasSee fig. 5.
According to the circuit theory superposition principle, the grid-connected current I is easily obtained from the graph of FIG. 4gThe expression is shown in formula (1).
Figure BDA0002600127810000072
Controlling the output phase voltage of the active damping inverter to meet Uf＝-KAIghBringing the relation into formula (1) to obtain
Figure BDA0002600127810000073
Since embodiments of the present invention only need to discuss the harmonic frequency domain, the variable I in equation (2)gAvailable of IghInstead, Ig＝Igh(ii) a Then, the formula (2) is arranged as
Figure BDA0002600127810000074
In connection with fig. 4 and equation (3), when the passive damper operates alone, i.e. by setting KAThe active damper is blocked as 0, and the passive damper is connected with the grid harmonic current I when working aloneghIs expressed as
Figure BDA0002600127810000075
Formulas (3) and (4) represent, respectively: when the coordinated damper works normally and the passive damper works alone, the harmonic current I of the grid connectionghAn expression; from the above equation 2, a single-phase equivalent circuit of the coordinated damper is obtained, as shown in fig. 5.
Fig. 5 shows: 1) the passive damper is equivalent to ZppA parallel branch circuit; because of the active damping inversion filter inductance LfSmall value (L)f0.1mH), therefore, Z can be considered to bepp≈Zpd. 2) The active damper is equivalent to a harmonic virtual impedance Z connected in series at the grid-connected sideasAnd Z isas＝KctKA。
Figure 6 provides an amplitude frequency response curve for a passive damper. It is evident that at 50Hz fundamental frequency, the passive damper generates a parallel resonance, ZppThe equivalent impedance of the branch in parallel is extremely large; as the frequency increases, the harmonic impedance will become smaller.
The equivalent harmonic impedance of the active damper is Zas＝KctKAThis means that: in a wide harmonic frequency range, ZasVirtual resistance characteristic (K) always kept constantASet to a normal number). At harmonic frequencies, ZasThe amplitude-frequency response curve is proportional to KAThus, Z is not provided hereinasAmplitude-frequency response graph of (a).
With reference to fig. 7 and 8, the mechanism of the broadband harmonic resonance damping of the tuned damper can be interpreted as follows:
(1) at fundamental (power frequency) the equivalent impedance Z of the passive damperppAs a result, the bypassed power frequency current is very little, as shown in fig. 7; equivalent fundamental impedance Z of active damperasAnd the power frequency current is zero, so that the power frequency current can be smoothly injected into a power grid.
(2) At harmonic frequencies, the higher the frequency, ZppThe smaller the harmonic impedance of the branch is, the short circuit of the branch is approximate, therefore, the broadband harmonic current is bypassed by the branch; the equivalent harmonic impedance of the active damper is KctKAAs can be seen from the parallel shunt principle, the harmonic current is difficult to inject into the power grid, as shown in fig. 8. Active damper equivalent impedance ZasThe harmonic current source is connected in series between the harmonic current source and the power grid, so that the harmonic impedance isolation function of the harmonic current source and the power grid can be realized, and the harmonic resonance caused by the source side-grid side impedance coupling is avoided.
(3) The active damper and the passive damper work in a coordinated mode, broadband harmonic treatment of a harmonic current pollution source is guaranteed, meanwhile, a harmonic impedance isolation function is achieved, and system instability factors caused by potential impedance interaction are avoided.
In order to realize effective treatment of the harmonic resonance of the broadband by the coordinated damper, on one hand, the harmonic component I of the grid-connected current must be accurately extractedgh(ii) a On the other hand, the active damping inverter outputs a phase voltage UfIt is necessary to stably, accurately and quickly track a given signal-KAIgh. Therefore, the active damping inverter control system is required to treat the broadband harmonic resonance and has the following characteristics:
1) dynamic tracking of IghAbility-active damping inverting transmissionOut-phase voltage UfCapable of dynamically tracking I from groundghThe conditions of sudden increase of harmonic amplitude, sudden change of harmonic frequency and the like occur.
2) Insensitivity to self internal structure parameter variation (perturbation) -mainly referring to active damping inversion filter inductor LfAnd its equivalent resistance RfDeviates from the nominal value.
3) Against the phase voltage upcAbility to disturb-caused by grid voltage fluctuations.
Industrial control methods, such as: proportional Integral (PI) control and dead beat control can achieve good steady-state tracking effect, and the application is mature and the design flow is standard. However, in the PI control mode, a zero is introduced to the origin of the S plane of the system in the integration link, so as to attract the dominant pole to approach the virtual axis, which causes a long-time tailing of the dynamic response of the system; therefore, the PI control method is not suitable for a scenario requiring an extremely high system dynamic response. Essentially, the dead beat control mode is proportional (P) control, so the dynamic property is excellent, and the control parameter design and the digital control are extremely simple and convenient to realize; nevertheless, its control effect depends heavily on the recognition accuracy of the mathematical model of the controlled object; the internal structure parameters slightly perturb, and the steady-state tracking performance is greatly reduced. Therefore, dead-beat control is not well suited to scenarios where the steady-state performance of the system is extremely demanding.
If the coordinated damper is required to efficiently manage the broadband harmonic resonance, the active damping inverter control system should stably, accurately and rapidly track the grid-connected harmonic current Igh(ii) a Should have perturbation insensitivity to the inversion filter parameters; should have an external phase voltage upcDisturbance has a resisting capability; in other words, the control system designed should be robust.
The embodiment of the invention observes the perturbation of the inverter filter inductance parameter and the voltage disturbance of the active damper interface; the observation items not only ensure the robustness of the control system, but also reduce buffeting of control input signals as much as possible, further weaken the nonlinear sliding mode motion effect and ensure the global robustness of the system. The robust current control method only has integral and first-order differential of variables; objectively, the digital implementation difficulty of the method is equivalent to that of a PID mode.
The mathematical model of the coordinated damper as the controlled object in the embodiment of the invention refers to the formula (1); wherein idIs a controlled variable, ufFor control input, upcIs the perturbation input. As can be seen from FIG. 3, the output current i of the damper is coordinateddThe following relationship is satisfied:
Figure BDA0002600127810000091
in the formula (5), the reaction mixture is,
Figure BDA0002600127810000092
for coordinating damper output current idThe superscript point of the symbol in the formula herein represents the derivative of the variable for which the symbol corresponds, and one point represents the first derivative.
The control targets of the coordinated dampers are: real-time extraction of grid-connected current IgOf harmonic components, i.e. Igh(ii) a Controlling the output voltage of the active damping inverter to meet the relationship: u shapef＝-KAIghAnd the broadband harmonic resonance damping effect can be realized.
As can be seen from FIG. 3, the active damper is equivalent to the voltage source KctUfBecause its inverting part is a voltage source type PWM modulated inverter. From a closed-loop control perspective, i.e. control target requirement Uf＝-KAIghThe equivalent voltage source is understood to be a "current controlled voltage source", the so-called CCVS.
In order to make the design process more general and make the variable symbol writing conform to the reading habit, the variable symbol in the formula (5) can be replaced, and the expression after replacement is:
Figure BDA0002600127810000101
in the formula (I), the compound is shown in the specification,
Figure BDA0002600127810000102
u＝Kctuf，d＝upc；h1and h2Respectively connected with active damping inversion filter inductance LfAnd its equivalent resistance RfThe value is related; also, u is the new control input variable and d is the new disturbance input variable. Variable h1And h2The filter parameters are filter parameters of the controlled object, and if the actual values of the filter parameters deviate from the nominal values, the internal structure parameters are perturbed. The physical meaning of the variable d is: the phase voltage borne by the active damping inverter is also a disturbance input variable of a control object. The active damper and the passive damper are used for carrying out series voltage division on the power grid voltage; if the voltage of the power grid fluctuates, the disturbance input variable d also changes correspondingly and acts on the controlled object.
In an embodiment of the present invention, a robust current controller with fixed switching gain is designed as follows. Defining damping current (controlled variable) idThe tracking error signal e of (a) is:
e＝id–id_ref (7)
in the formula (7), id_refIs a damping current reference.
The following proportional-integral slip form surface is designed:
Figure BDA0002600127810000103
in the formula (8), kpIs a proportionality coefficient, kiIs an integral coefficient.
The following Lyapunov (Lyapunov) function was constructed:
Figure BDA0002600127810000104
obviously v1Is positive.
Next, a control law for the controlled object, i.e., equation (6), is found, so that the Lyapunov function v1Derivative with respect to time
Figure BDA0002600127810000105
Is negative half definite.
Finding v1Derivative with respect to time, given as:
Figure BDA0002600127810000106
derivation of the sliding mode surface function, i.e. derivation of the time derivative of equation (8) to obtain
Figure BDA0002600127810000107
Bringing formula (11) into formula (10) to obtain
Figure BDA0002600127810000111
From equation (7), the derivative of the tracking error signal e with respect to time is readily obtained
Figure BDA0002600127810000112
This is then taken into formula (12) to give:
Figure BDA0002600127810000113
bringing formula (6) into formula (13) to obtain:
Figure BDA0002600127810000114
designing tracking and switching items, namely enabling the control input variable u to have the following form:
Figure BDA0002600127810000115
in the equation (15), ρ is a switching gain for controlling the input switching term and is a normal number. To ensure that the state variables have a sliding mode, i.e. the state variables e and
Figure BDA0002600127810000116
attracted by the slip manifold and stopped thereon, and slid toward the origin (balance point), requires: and | rho | is more than or equal to | d |, namely the switching gain is more than or equal to the boundary of the input variable d with the most serious disturbance.
It should be understood that the control input variables u are of practical physical significance; by the relationship u ═ KctufIt can be known that u is the output phase voltage of the active damping inverter after being converted to the primary side of the coupling transformer. In fact, the voltage is the result after PWM, corresponding to a modulation signal of u/Kct。
Bringing formula (15) into formula (14) and finishing to obtain:
Figure BDA0002600127810000117
it is clear that,
Figure BDA0002600127810000118
the function is semi-negative and the v function is positive. Therefore, with the control law of equation (15) under the premise that there is no perturbation in the internal structural parameters (filter inductance), when time t tends to ∞, the state variables e and
Figure BDA0002600127810000119
will return to the origin; i.e. closed loop control systems in
Figure BDA00026001278100001110
The origin of (a) is progressively stabilized.
In fact, the internal structural parameter h1And h2Perturbation (i.e. L)fAnd RfDeviation from the true value of the nominal value), sudden change of external disturbance d (u caused by network voltage fluctuation)pcFluctuation) cannot be avoided. These perturbation and perturbation factors cause the state variables e and
Figure BDA00026001278100001111
deviation fromThe balance surface s is balanced, and the existence condition of the sliding mode can be damaged; i.e. the state variables of the system cannot move on the set sliding manifold and approach the origin.
If a sliding mode exists, namely the control system is ensured to have the capability of resisting larger internal structure parameter perturbation and the most serious external disturbance, the switching gain rho must be preset to be a larger value; enabling rho to offset the sum of possible and most severe perturbation and perturbation effect effects; namely, under any working condition, the condition | rho | is more than or equal to | d | can be ensured.
However, the value of the switching gain ρ is fixed and conservative (large value), which causes the control variable u to generate serious buffeting, i.e., causes the motion state to repeatedly and continuously pass through the sliding manifold up and down with a large amplitude, aggravates the motion effect of the non-ideal sliding mode, and reduces the robustness of the control system. From the power electronic perspective, buffeting introduces high frequency ripples into the modulated signal and is reproduced in the form of harmonic current at the damping current idIn (1).
Nevertheless, buffeting is a necessary product of variable structure control, and is a power for ensuring that a motion state slides on a sliding manifold and approaches an origin, so that the buffeting is eliminated, and the robustness of the system is completely eliminated. Thus, embodiments of the present invention attenuate buffeting rather than completely destroy it. Therefore, a switching gain self-adaption law can be designed, lumped uncertain factors caused by perturbation of filtering parameters and voltage disturbance of a power grid are calculated in real time, and the factors are offset by the switching gain in real time; and on the premise of ensuring the existence of a sliding mode, the buffeting of the control input is reduced as much as possible.
In order to realize automatic adjustment of the switching gain rho and avoid severe buffeting of control input caused by conservative and fixed-valued switching gain, so that the robustness of a control system is prevented from deteriorating, a Lyapunov function is redesigned:
Figure BDA0002600127810000121
wherein gamma is an adaptive coefficient and is a normal number;
Figure BDA0002600127810000122
an observation error of ρ, and
Figure BDA0002600127810000123
obviously v2Is positive.
Next, a control law for the controlled object, i.e., equation (6), is found, so that the Lyapunov function v2Derivative with respect to time
Figure BDA0002600127810000124
Is negative half definite. Then, when time t tends to ∞, the vector
Figure BDA0002600127810000125
Will tend to be [0,0,0,0 ]]I.e. the control system is progressively stabilized.
Finding v2Derivative with respect to time, given as:
Figure BDA0002600127810000126
in pair formula (18)
Figure BDA0002600127810000127
The terms are equivalently transformed in 2 steps as follows: first, formula (11) is substituted
Figure BDA0002600127810000128
In an item
Figure BDA0002600127810000129
Next, the intermediate calculation formula is replaced with the formula (6)
Figure BDA00026001278100001210
The equivalent transformation process is shown in formula (19).
Figure BDA00026001278100001211
Simulating a perturbation parameter-free control law, namely an equation (15), and designing the perturbation parameter control law; assume that the new tracking and switching control laws are:
Figure BDA0002600127810000131
in the formula (I), the compound is shown in the specification,
Figure BDA0002600127810000132
and
Figure BDA0002600127810000133
are respectively h1And h2An estimated value of, and
Figure BDA0002600127810000134
Δh1and Δ h2Are the amount of uptake, i.e. Δ h1And Δ h2Are respectively deviation from true value h1And h2The size of (2). True value h cannot be obtained in practice1And h2Thus, Δ h1And Δ h2Are both objective. sgn (X) denotes a sign function when X>0 time output 1, X<Output-1 at 0.
Bringing formula (20) into formula (18)
Figure BDA0002600127810000135
The item, namely, the belt-in (19), includes:
Figure BDA0002600127810000136
bringing formula (21) into formula (18) to obtain
Figure BDA0002600127810000137
Observe the items in the "middle brackets" on the right side of the equal sign of formula (22), except
Figure BDA0002600127810000138
Besides the terms, the rest of the terms perturb the filter parameter (Δ h)1And Δ h2) External voltage disturbances (d); therefore, these perturbation and perturbation terms can be regarded as "lumped uncertainty factor" and used as dlumpRepresents:
Figure BDA0002600127810000139
then, equation (22) can be simplified as:
Figure BDA00026001278100001310
due to the fact that
Figure BDA00026001278100001311
The condition of negative half definite is satisfied, and the progressive stability of the closed-loop system can be ensured. For this purpose, can design
Figure BDA00026001278100001312
Law of observation such that
Figure BDA00026001278100001313
Just cancel out
Figure BDA00026001278100001314
D in (1)lumpItem, and then ensure
Figure BDA00026001278100001315
The negative half-definite condition is satisfied.
For this purpose, in formula (24) can be eliminated
Figure BDA00026001278100001316
Item (i) can be represented by
Figure BDA00026001278100001317
The item design is as follows:
Figure BDA00026001278100001318
in other words,
Figure BDA00026001278100001319
the observation law of (2) can be designed as follows:
Figure BDA0002600127810000141
substituting formula (26) for formula (24) to obtain:
Figure BDA0002600127810000142
it is clear that,
Figure BDA0002600127810000147
is negatively semi-definite, and v2Is positive. Therefore, the tracking and switching control law shown in the formula (20) is applied to the controlled object (namely, the formula (6)), the filtering parameter perturbation and the grid voltage disturbance are observed in real time (the self-adaptive law is the formula (26)), and the closed-loop control system is gradually stable. In other words, as long as the initial state is maintained
Figure BDA0002600127810000143
Even if the filter parameters perturbate, the grid voltage fluctuates, the motion states e and
Figure BDA0002600127810000144
will eventually return to the origin; i.e. closed loop control systems in
Figure BDA0002600127810000145
Figure BDA0002600127810000146
The origin of (a) is progressively stabilized. Therefore, the control method of the embodiment of the invention not only ensures the gradual stability of the system, but also reduces buffeting of the control input signal and improves the robustness of the control system.
Refer to FIG. 9 and FIG. 9Fig. 10, wherein fig. 9 is a schematic diagram of coordinated damping robust current control including a main circuit, and fig. 10 is a schematic diagram of a coordinated damping robust three-phase current control method. The input signals of the coordinated damping robust current controller are the following three-phase signals (subscripts a, b and c are omitted in the province): damping current idDamping current reference id_refAnd a tracking error signal e.
The above input signal is obtained by the following steps:
1) damping current idDirectly extracted by the hall current sensor.
2) Damping current reference id_ref＝-KAighNamely: extraction of grid-connected current i by Hall current sensorgThen, the harmonic component i is extracted by a software modeghThen multiplied by an active damping proportionality coefficient KA。
3) The tracking error signal e, namely: damping current (controlled variable) idSatisfies e ═ i, of the tracking error signald–id_refThe relationship can be obtained by real-time calculation in a digital controller.
The coordinated damping robust current controller is composed of 3 sub-control units, and control parameters are completely the same. They respectively realize: dynamic tracking damping current reference i for output phase current of active damping inverterd_ref,a、id_ref,b、id_ref,cDynamic tracking of (2). Each sub-control unit comprises 3 modules: the sliding mode surface, the tracking and switching term and the switching gain are adaptive and respectively correspond to an equation (8), an equation (20) and an equation (26).
In the tracking and switching term, equation (20),
Figure BDA0002600127810000151
and
Figure BDA0002600127810000152
are respectively h1And h2An estimated value of (A), and
Figure BDA0002600127810000153
in the case of the implementation of digital control programming,
Figure BDA0002600127810000154
and
Figure BDA0002600127810000155
value can be taken together with filter inductance LfAnd R thereoffAre the same. On the one hand, the nominal value cannot be exactly equal to the true value, and on the other hand, the filter element inductance changes (perturbation of the parameters) as the environmental conditions and the operating time change. Therefore, even if the nominal value is adopted, there is always a model identification error.
The switching gain self-adaptation formula (26) can jointly bring 'lumped uncertain factors'd to perturbation of filter parameters and power grid voltage disturbancelumpCarrying out observation; in other words,
Figure BDA0002600127810000156
dynamically modifying self-size for real-time cancellation of dlumpThe impact on the control system.
The robust current controller operating mechanism is described as follows:
calculating a sliding mode surface module: calculating a real-time value of the sliding mode surface function s by using a tracking error signal e obtained in real time according to a formula (8); and sending the real-time calculated value of s to a tracking and switching item module and a switching gain self-adaption module.
The calculation process of the switching gain self-adaption module comprises the following steps: receiving the calculation output from the sliding mode surface module in real time, and calculating the derivative of the switching gain observation value to the time by the formula (26)
Figure BDA0002600127810000157
And performing time integral processing on the derivative to obtain a switching gain observed value
Figure BDA0002600127810000158
Will be provided with
Figure BDA0002600127810000159
The real-time calculated value is sent to a tracking and switching item module.
The calculation process of the tracking and switching item module comprises the following steps: accepting transmissions from a switching gain adaptation module
Figure BDA00026001278100001510
Receiving s transmitted from the sliding mode surface module and receiving damping current idDamping current reference id_refA tracking error signal e; the control output signal u is calculated in real time using equation (20) with the 5 real-time signals as inputs.
Three-phase pulse width modulation module: the calculated control output signal u (u)a、ub、uc) Six paths of driving pulses are output through a three-phase pulse width modulation module, sent to the IGBTs of the active damping inversion component and used as grid driving signals of the IGBT and the IGBT.
Control input variable ua、ub、ucSix paths of driving pulses are transmitted to an active damping inverter (consisting of three bridge arms IGBT + diode) through three-phase pulse width modulation, and closed-loop control ensures that the output phase voltage of the inverter meets uf＝-KAighThe relationship (voltage source type PWM inverter, which can be considered as a current controlled voltage source, i.e., CCVS).
In the embodiment of the invention, an MATLAB simulation model is also utilized for verifying the treatment effect of the robust current control method on the broadband harmonic resonance. The structure of the simulation main circuit and the controller is completely consistent with that of fig. 9 and 10 respectively.
The simulation parameters are set as follows:
(1) a passive damper: l isp＝16.9mH，Cp＝600μF；
(2) Coupling the transformer: kct1 (i.e. transformer transformation ratio 1);
(3) an active damper: l isf＝0.1mH，Rf＝0.0168Ω，KA＝15；
(4) Robust current controller:
a slip form surface: k is a radical ofp＝5，ki＝20；
Lyapunov function: γ is 1;
tracking and switching item:
Figure BDA0002600127810000161
(true value h)1＝0.1)，
Figure BDA0002600127810000162
(true value h)2＝-0.0168)；
(5) And (3) power grid parameters: zg＝0.002+jω0.0012Ωug220V (one phase effective value RMS).
The following is a harmonic pollution source frequency mutation test. The harmonic pollution source emits fundamental wave current and is mixed with 5 th, 7 th, 11 th and 13 th harmonic current. In the 1 st second, the harmonic current frequency of the pollution source is instantaneously switched to 17, 19, 23 and 25. Fig. 11 and 12 are simulation waveforms of the a-phase harmonic current source and the a-phase grid-connected current before and after the 1 st-second abrupt change occurs. Referring to FIG. 11, before 1 second, the pollution source emits 5, 7, 11, 13 harmonic currents; 0.96 to 0.98 seconds, i in the 1 power frequency periods,aThe Total Harmonic Distortion (THD) of 27.63%. After 1 second, the pollution source emits 17, 19, 23 and 25 harmonic currents instead; 1.02 th to 1.04 th seconds, i in the 1 power frequency periods,aThe THD of (a) was still 27.63%, but i after mutation was compared with i before mutations,aThe waveform exhibits a ripple at a higher frequency. Referring to fig. 12, with the robust current controller shown in fig. 10, the coordinated damper can effectively handle harmonic currents; before and after mutation, ig,aThe THD of (A) is less than 3%. More importantly: after the sudden change occurs, the grid-connected current i can not be seeng,aAny transition process exists; this shows that the whole control system has extremely strong robustness, in other words, the dynamic governing effect of harmonic resonance is excellent. In conclusion, the grid-connected current THD index and the controlled variable igTransient behavior is sufficient to account for: the coordinated damping robust current control method is completely competent for harmonic current frequency mutation, and under the extremely severe condition, harmonic resonance governance requirements are met.
FIG. 13 and FIG. 14 are the movement state traces of the controlled system before and after the frequency mutation of the harmonic pollution source; wherein the controlled systemSystematic 2 state variables: error eaAnd integral of error
Figure BDA0002600127810000171
Constituting the phase plane of the system state. FIG. 13 may decompose the system state trajectory into the following motions:
1) the system state moves from the starting point position in the anticlockwise direction, and once the system state falls into a sliding manifold (a balance surface and a sliding mode surface), the system state vibrates up and down along the sliding manifold and tends to the original point (a balance point);
2) after moving along the sliding manifold for a period of time, the system state penetrates out of the sliding manifold, continues to move in the counterclockwise direction, and waits to be intersected with the sliding manifold again and fall into the sliding manifold;
3) every time the system falls into the sliding manifold, the system state continuously approaches the origin along the direction indicated by the sliding manifold; after passing through the sliding manifold for a plurality of times, the system state will oscillate slightly near the origin-the control system shows extremely strong robustness.
When the harmonic pollution source generates the frequency sudden change shown in fig. 11, the track of the motion state of the system is shown in fig. 14. FIG. 14 shows that: before the sudden change occurs, the motion state of the system falls into a range strongly attracted by an origin, and the control system shows extremely strong robustness, namely the motion state cannot break away from the constraint of a balance point when the harmonic current frequency sudden change is responded; this also explains why the grid-connection current i is hardly seen in fig. 13gThere is any reason for the transition.
The harmonic pollution source amplitude spikes were tested below. The harmonic pollution source emits fundamental wave current and is mixed with 5 th, 7 th, 11 th and 13 th harmonic current. At 1 second, the harmonic current amplitudes of the pollution source are instantaneously doubled. Fig. 15 and 16 are simulation waveforms of the a-phase harmonic current source and the a-phase grid-connected current before and after the occurrence of the sudden increase in the amplitude of each harmonic current at the 1 st second, respectively. Referring to fig. 15, before 1 second, the pollution source emits 5 th, 7 th, 11 th, and 13 th harmonic currents; 0.96 to 0.98 seconds, i in the 1 power frequency periods,aThe Total Harmonic Distortion (THD) of 27.63%. After 1 second, emitted by the sourceDoubling the amplitude of the harmonic current; 1.02 th to 1.04 th seconds, i in the 1 power frequency periods,aThe THD rise of (D) was 55.25%. Referring to FIG. 16, it can be seen that with the robust current controller shown in FIG. 4, the coordinated damper is able to effectively attenuate harmonics; before and after sudden increase, ig,aThe THD of (A) is less than 5%. And more importantly: after sudden increase, almost no grid-connected current i can be seeng,aAny transition process exists; this shows that the whole control system has extremely strong robustness, in other words, the dynamic governing effect of harmonic resonance is excellent. In conclusion, the grid-connected current THD index and the controlled variable ig,aTransient behavior is sufficient to account for: the coordinated damping robust current control method is completely competent for the sudden amplitude increase of harmonic current, and under the extremely severe condition, the harmonic resonance treatment is required.
The apparatus of an embodiment of the present invention, referring to fig. 17, includes: the error signal tracking module 100 is configured to acquire three-phase damping current and three-phase grid-connected current, obtain a damping current reference according to a harmonic component of the grid-connected current, and further obtain a tracking error signal of the damping current; the control signal processing module 200 is used for obtaining a real-time value of the sliding mode surface function according to the tracking error signal, dynamically updating a switching gain observation value based on a self-adaptive law model, and obtaining an output control signal based on a perturbation parameter control law model; and the three-phase pulse width modulation module 300 is used for modulating the output control signal, outputting six paths of driving pulses and driving the grid of the IGBT of the active damping inversion component. In the embodiment of the present invention, the control signal processing module 200 includes three single-phase control submodules 210, which are respectively used for obtaining A, B, C three-phase output control signals. The single-phase control sub-module 210 includes: a sliding mode surface module 211, configured to obtain a real-time value of a sliding mode surface function according to the tracking error signal; a switching gain adaptive module 212, configured to dynamically update a switching gain observation value based on an adaptive law model according to a real-time value of the sliding mode surface function; and the tracking switching module 213 is configured to obtain an output control signal based on the perturbation parameter control law model according to the damping current, the damping current reference, the tracking error signal, the real-time value of the sliding mode surface function, and the switching gain observation value. In an embodiment of the invention, the error signal tracks the modulusThe block 100 collects A, B, C three-phase damping current data and grid-connected current three-phase data, the processing process of each item is the same, taking phase A as an example, firstly, a damping phase A current is collected through a Hall current sensor, grid-connected current phase A data is extracted, harmonic component of phase A is extracted, a damping phase A current reference is obtained, and then a tracking signal difference of the damping phase A current is calculated; and transmits the tracking signal error signals of the damped phase a current, the damped phase a current reference, and the damped phase a current to the single phase control submodule (phase a) 210. Referring to fig. 10, a real-time value of the sliding mode surface function is calculated by the sliding mode surface module 211 according to equation (8), and is transmitted to the switching gain adaptation module 212 and the tracking switching module 213. The switching gain adaptive module 212 calculates the switching gain observed value according to the formula (26) and transmits the switching gain observed value to the tracking switching module 213, and the tracking switching module 213 obtains the output control signal u according to the formula (20)a. The phase B and phase C single-phase control submodules (the phase B and phase C single-phase control submodules are the same as the phase a single-phase control submodule internal module, so the phase B and phase C single-phase control submodules are not marked in fig. 17) similarly perform the above calculation according to the damping current and the grid-connected current of the phase B and phase C single-phase control submodules to respectively obtain output signalsbAnd uc. The three output signals are modulated by the three-phase pulse width modulation module 300 to obtain six paths of driving pulses. The output end of the three-phase pulse width modulation module 300 is connected with the gate of the IGBT of the active damping inverter component, and the output six driving pulses are used as the driving signal of the gate of the IGBT of the active damping inverter component.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.

Claims (9)

1. A broadband harmonic resonance coordinated damping robust current control method is characterized by comprising the following steps:
s100, collecting three-phase damping current and three-phase grid-connected current, obtaining damping current reference according to harmonic components of the grid-connected current, and further obtaining a tracking error signal of the damping current;
s200, obtaining a real-time value of a sliding mode surface function according to the tracking error signal, dynamically updating a switching gain observation value based on a self-adaptive law model, and obtaining an output control signal based on a perturbation parameter control law model;
and S300, modulating the signal through a three-phase pulse width modulation module according to the output control signal, outputting six paths of driving pulses, and driving the grid of the IGBT of the active damping inversion component.
2. The method of claim 1, wherein the step S100 comprises:
s110, collecting three-phase damping current and three-phase grid-connected current through a Hall current sensor;
s120, extracting harmonic component i of the grid-connected currentghAccording to the active damping proportionality coefficient KADeriving the damping current reference id_ref；
S130, according to the damping current and the damping current reference id_refAnd obtaining the tracking error signal e, wherein the calculation method of the tracking error signal e is as follows: e ═ id–id_refWherein idAnd id_refRespectively representing the damping current and the damping current reference of the same phase.
3. The broadband harmonic resonance coordinated damping robust current control method according to claim 1, wherein the damping current is referenced to id_refThe obtaining method comprises the following steps: i.e. id_ref＝-KAighIn which K isARepresenting the active damping proportionality coefficient, ighRepresents a harmonic component of the grid-tied current in phase with the damping current.
4. The wideband harmonic resonance coordinated damping robust current control method according to claim 1, wherein the sliding-mode surface function comprises:
Figure FDA0002600127800000011
wherein s represents the sliding mode surface function, e represents the tracking error signal, kpIs a proportionality coefficient, kiT represents time as an integral coefficient.
5. The method of claim 4, wherein the method of deriving the switching gain observation based on the adaptive law model comprises:
obtaining a derivative of the switching gain observation value according to the adaptive law model, wherein the adaptive law model is as follows:
Figure FDA0002600127800000021
wherein the content of the first and second substances,
Figure FDA0002600127800000022
representing switching gain observations
Figure FDA0002600127800000023
S represents the sliding mode surface function; gamma represents an adaptive coefficient and is a normal number;
derivative of the switching gain observations
Figure FDA0002600127800000024
Integrating to obtain the switching gain observed value
Figure FDA0002600127800000025
6. The method according to claim 4, wherein the perturbed parametric control law model comprises:
Figure FDA0002600127800000026
wherein u is an output control signal,
Figure FDA0002600127800000027
and
Figure FDA0002600127800000028
respectively represent h1And h2An estimated value of (A), and
Figure FDA0002600127800000029
Figure FDA00026001278000000210
kprepresents the proportionality coefficient, idIs representative of the damping current(s),
Figure FDA00026001278000000211
representing the damping current reference id_refDerivative of, LfRepresenting active damping inverter filter inductance, RfRepresents LfEquivalent resistance of, KctRepresenting the transformation ratio coefficient of the coupling transformer, sgn () representing the sign function, kiRepresenting an integral coefficient, s representing the sliding mode surface function,
Figure FDA00026001278000000212
representing the switching gain observation, e representing the tracking error signal.
7. The method of claim 6, wherein the method further comprises tuning the harmonic resonance to damp the current,
Figure FDA00026001278000000213
and
Figure FDA00026001278000000214
respectively taking active damping inversion filter inductance LfAnd RfNominal value ofWherein R isfRepresents LfThe equivalent resistance of (c).
8. A broadband harmonic resonance coordinated damping robust current control device using the method of any one of claims 1 to 7, comprising:
the error signal tracking module is used for acquiring three-phase damping current and three-phase grid-connected current, obtaining damping current reference according to harmonic component of the grid-connected current and further obtaining a tracking error signal of the damping current;
the control signal processing module is used for obtaining a real-time value of the sliding mode surface function according to the tracking error signal, dynamically updating a switching gain observation value based on a self-adaptive law model, and obtaining an output control signal based on a perturbation parameter control law model;
and the three-phase pulse width modulation module is used for modulating the output control signal, outputting six paths of driving pulses and driving the grid of the IGBT of the active damping inversion component.
9. The broadband harmonic resonance coordinated damping robust current control device according to claim 8, wherein the control signal processing module comprises three single-phase control sub-modules for obtaining the output control signals of three phases respectively, comprising:
the sliding mode surface module is used for obtaining a real-time value of a sliding mode surface function according to the tracking error signal;
the switching gain self-adaptive module is used for dynamically updating the switching gain observation value based on the self-adaptive law model according to the real-time value of the sliding mode surface function;
and the tracking switching module is used for obtaining the output control signal based on the perturbed parameter control law model according to the damping current, the damping current reference, the tracking error signal, the real-time value of the sliding mode surface function and the switching gain observation value.
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