CN113162021A - VSC inner loop current control method based on uncertain interference estimation - Google Patents
VSC inner loop current control method based on uncertain interference estimation Download PDFInfo
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Abstract
The invention discloses a VSC inner loop current control method based on uncertain interference estimation, which comprises the following steps: s1, constructing a VSC current mathematical model of a direct-current power distribution network; s2, carrying out standardization processing on the current in the VSC current mathematical model to obtain a VSC inner ring current uncertain dynamic model; s3, obtaining a VSC inner ring current reference model based on uncertain interference estimation, an error equation based on uncertain interference estimation, and uncertainty and disturbance estimation values based on a VSC inner ring current uncertain dynamic model; and S4, calculating a control rule of the VSC inner ring current according to the VSC inner ring current reference model, the error equation and the uncertainty and disturbance estimation value. The method can solve the problem of poor interference resistance under the traditional PI control of the VSC inner loop current, improves the robustness of the power grid system, and greatly simplifies the parameter setting process of the power grid system.
Description
Technical Field
The invention relates to the field of direct-current power distribution networks, in particular to a VSC inner loop current control method based on uncertain interference estimation.
Background
With the development of new energy technologies such as photovoltaic, wind power and storage battery, the direct current power distribution network has certain flexibility and convenience for various new energy accesses and receives more and more attention. In a dc power distribution network structure, a VSC (voltage source converter) is an important element that plays a role of rectification, and therefore, control of the VSC is very important for stable operation of the dc power distribution network system.
The double-loop control consisting of the voltage outer loop and the current inner loop is a widely applied VSC traditional control strategy, and the double-loop control uses a traditional synchronous coordinate system PI controller. For the inner loop current controller, the current regulated by the synchronous coordinate system PI controller is a direct current quantity, so that a better tracking effect can be ensured theoretically. However, in a dc distribution network environment, the operation of VSC is often affected by system disturbances; in addition, in the design process of the VSC controller, the problem of uncertain parameters widely exists, which makes the PI controller face a huge challenge of parameter setting when in application, the parameter selection process often adopts a trial and error method, and when the parameter selection is inappropriate, it is difficult to achieve a more ideal robust control effect under the PI control.
Disclosure of Invention
In view of the above, the present invention aims to overcome the defects in the prior art, and provide a VSC inner loop current control method based on uncertain interference estimation, which can solve the problem of poor immunity under the conventional PI control of the VSC inner loop current, improve the robustness of the power grid system, and greatly simplify the parameter setting process of the power grid system.
The invention discloses a VSC inner loop current control method based on uncertain interference estimation, which comprises the following steps:
s1, constructing a VSC current mathematical model of a direct-current power distribution network;
s2, carrying out standardization processing on the current in the VSC current mathematical model to obtain a VSC inner ring current uncertain dynamic model;
s3, obtaining a VSC inner ring current reference model based on uncertain interference estimation, an error equation based on uncertain interference estimation, and uncertainty and disturbance estimation values based on a VSC inner ring current uncertain dynamic model;
and S4, calculating a control rule of the VSC inner ring current according to the VSC inner ring current reference model, the error equation and the uncertainty and disturbance estimation value.
Further, in step S1, constructing a VSC current mathematical model of the dc power distribution network specifically includes:
s11, determining a VSC alternating current side dynamic differential equation of the direct current distribution network:
wherein, Vsa、VsbAnd VscIs the three-phase voltage of an alternating current system; vta、VtbAnd VtcThe three-phase voltage at the VSC alternating current side; l issThe sum of the equivalent inductance of the connecting transformer and the reactor and the leakage inductance of the transformer; i.e. ia、ibAnd icThree-phase current of an alternating current system; t is time; rs+ronI represents an alternating-current side current for an equivalent resistance connecting the transformer and the reactor; rsIs an equivalent resistance connected with the transformer; r isonA switching loss for connecting the transformer and the reactor;
s12, carrying out coordinate transformation processing on the VSC alternating side dynamic differential equation to obtain a VSC current mathematical model:
wherein idThe component of the alternating side current on the d axis under the d-q coordinate system is shown; i.e. iqThe component of the alternating side current on the q axis under a d-q coordinate system is shown; t is time; rs+ronAn equivalent resistance for connecting the transformer and the reactor; omega is the angular frequency of an alternating current system; u. ofcdA control signal of a d axis of the VSC in a d-q coordinate system; u. ofcqA control signal of a q axis of the VSC under a d-q coordinate system; u. ofsdThe component of the alternating current power supply voltage on the d axis under the d-q coordinate system; u. ofsqIs the component of the alternating current power supply voltage on the q axis in the d-q coordinate system.
Further, in step S2, the VSC inner loop current uncertainty dynamic model is:
wherein the content of the first and second substances,
a derivative with respect to time t of a system state vector; x (t) is a state vector at time t, where x is [ i ═ id iq]T(ii) a u (t) is a control input vector at time t, and u ═ ucd ucq]T；f0(t) a known perturbation vector at time t, said
Ls0A rated value which is the sum of the equivalent inductance of the coupling transformer and the reactor and the leakage inductance of the transformer; a (t) is a state matrix at time t
B (t) is a control matrix at time t
f (t) is an unknown perturbation vector at time t, f (t) ═ fd(t) fq(t)]T，fd(t) is the component of the unknown disturbance vector at the t moment on the d axis; f. ofq(t) unknown disturbance vector at t moment is on q axisThe component (c).
Further, f isd(t) and fq(t) determined according to the following equation:
wherein, said Δ Ls＝Ls-Ls0，id(t) is the component of the alternating side current on the d axis under the d-q coordinate system at the time t; said Δ Rs＝Rs-Rs0，Rs0A rated value for an equivalent resistance of the link transformer; the delta ron＝ron-ron0，ron0A rated value of a switching loss connecting the transformer and the reactor; i.e. iq(t) is the component of the alternating side current on the q axis under the d-q coordinate system at the time t; u. ofsd(t) is the component of the alternating current power supply voltage on the d axis under the d-q coordinate system at the moment t; u. ofcd(t) is a d-axis control signal of the VSC under a d-q coordinate system at the moment t; sigmad(t) is the lumped uncertainty and disturbance of the d-axis at time t; sigmaq(t) is the lumped uncertainty and disturbance of the q axis at the time t; i.e. iq(t) is the component of the alternating side current on the q axis under the d-q coordinate system at the time t; u. ofsq(t) is the component of the voltage of the alternating current power supply on the q axis under the d-q coordinate system at the moment t; u. ofcqAnd (t) is a control signal of a q axis of the VSC under a d-q coordinate system at the time t.
Further, the VSC inner loop current reference model based on the uncertain interference estimation is:
wherein the content of the first and second substances,
is the reference state vector at time t; x is the number ofm(t) a reference state vector at time t, said xm(t)＝[idm iqm]T，idmIs in the reference model idA state vector of (a); i.e. iqmIs prepared from radix GinsengIn examination model iqA state vector of (a); u. ofm(t) is a system reference instruction at time t, um(t)＝[ucd ucq]T；AmIs a constant matrix, the
BmIs a constant matrix, the
Alpha is the bandwidth parameter of the filter.
Further, the error equation based on the uncertain interference estimation is:
e(t)＝xm(t)-x(t)；
wherein e (t) is the state error at time t; x (t) is a state vector at time t, where x ═ id iq]T。
Further, the uncertainty and disturbance estimate is:
wherein the content of the first and second substances,
the estimated value of the lump uncertainty and disturbance at the time t; sigma (t) is the lump uncertainty and disturbance at the time t; gfAnd (t) is an uncertainty and disturbance estimation filter at the time t.
Further, step S4 specifically includes:
s41, determining an equation met by an inner loop current control law:
Bu(t)＝Amx(t)+Bmum(t)-Ax(t)-Ke(t)-(d0(t)+f(t))；
wherein K is an error feedback gain matrix; d0(t) is the known perturbation vector at time t;
s42, solving an equation which is satisfied by the inner loop current control law to obtain a solution of the VSC inner loop current robust control law based on uncertain interference estimation:
wherein the content of the first and second substances,
is an inverse laplace transform; s is a laplace operator; is a convolution symbol;
s43, parameter transformation is carried out on the solution of the robust control law of the VSC inner loop current based on the uncertain interference estimation, and the VSC physical quantity of the direct-current power distribution network is obtained:
wherein idrefIs a component i of the alternating side currentdA reference value of (d); i.e. iqrefIs a component i of the alternating side currentqTo the reference value of (c).
The invention has the beneficial effects that: according to the VSC inner loop current control method based on the uncertain interference estimation, all uncertainties and disturbances suffered by a VSC inner loop current control part are estimated and compensated by adopting the uncertain interference estimator, the problem of poor immunity under the traditional PI control of the VSC inner loop current is solved, the direct current bus voltage can be well controlled, and the system robustness is guaranteed; meanwhile, the control parameters can be simply expressed as two bandwidth parameters alpha and beta with uncoupled control effect, compared with the traditional PI control method of the VSC inner loop current, the parameter setting process is greatly simplified, and appropriate parameters are easily selected, so that a better robust control effect is achieved.
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The invention is further described below with reference to the following figures and examples:
FIG. 1 is a schematic flow diagram of the process of the present invention;
FIG. 2 is a topology and control structure diagram of a two-level VSC;
FIG. 3 is a schematic diagram of an inner loop current robust controller according to the present invention;
FIG. 4 is a diagram illustrating the DC voltage control effect of a conventional PI controller for inner loop current;
fig. 5 is a diagram illustrating the dc voltage control effect of the inner loop current controller according to the present invention.
Detailed Description
The invention is further described with reference to the drawings, as shown in fig. 1:
the invention discloses a VSC inner loop current control method based on uncertain interference estimation, which comprises the following steps:
s1, constructing a VSC current mathematical model of a direct-current power distribution network;
s2, carrying out standardization processing on the current in the VSC current mathematical model to obtain a VSC inner ring current uncertain dynamic model;
s3, obtaining a VSC inner ring current reference model based on uncertain interference estimation, an error equation based on uncertain interference estimation, and uncertainty and disturbance estimation values based on a VSC inner ring current uncertain dynamic model;
and S4, calculating a control rule of the VSC inner ring current according to the VSC inner ring current reference model, the error equation and the uncertainty and disturbance estimation value.
On one hand, the invention adopts the uncertain interference estimator to estimate and compensate all uncertainties and disturbances suffered by the VSC inner loop current control part, and solves the problem of poor immunity under the traditional PI control of the VSC inner loop current, thereby better controlling the voltage of the direct current bus and ensuring the robustness of the system; on the other hand, the control parameters can be simply expressed as two bandwidth parameters alpha and beta with uncoupled control effect, compared with the traditional PI control method of the VSC inner loop current, the parameter setting process is greatly simplified, and appropriate parameters are easily selected, so that a better robust control effect is achieved.
It should be noted that, in order to better understand the design idea of the present invention, the following modified portions of the present invention are described: as shown in fig. 2, the control principle of VSC in the rectifier operating state is: by measuring voltage on the DC sideThe current is subjected to constant active power control, constant direct current voltage control, droop control and the like to obtain idrefWhile i is generated by constant reactive power control or constant AC voltage controlqref(wherein, idrefIs a component i of the alternating side currentdReference value of iqrefIs a component i of the alternating side currentqReference value of (d); and further obtaining a direct-current voltage reference value, and inputting the direct-current voltage reference value into the VSC voltage and current double-loop PI control system. The double-loop PI control system is generally completed under a synchronous rotation dq coordinate system; the outer loop control generally provides a current reference for the inner loop current control to control the system dc side voltage or the inverter power. Inner loop current control by quickly tracking its reference value idrefAnd iqrefAnd outputting an alternating current side current component i under a dq coordinate systemdAnd iqTherefore, the PWM input to the IGBT is changed in a mode of controlling the duty ratio, so that the purpose of controlling the output voltage of the VSC direct current side is achieved, and the improved part of the invention is a current PI control part in double-loop control.
In this embodiment, in step S1, a VSC current mathematical model of the dc power distribution network is constructed, which specifically includes:
s11, determining a VSC alternating current side dynamic differential equation of the direct current distribution network:
wherein, Vsa、VsbAnd VscIs the three-phase voltage of an alternating current system; vta、VtbAnd VtcThe three-phase voltage at the VSC alternating current side; l issThe sum of the equivalent inductance of the connecting transformer and the reactor and the leakage inductance of the transformer; i.e. ia、ibAnd icThree-phase current of an alternating current system; t is time; rs+ronI represents an alternating-current side current for an equivalent resistance connecting the transformer and the reactor; rsIs an equivalent resistance connected with the transformer; r isonA switching loss for connecting the transformer and the reactor is expressed as an equivalent resistance;
s12, carrying out park coordinate transformation on the VSC alternating-current side dynamic differential equation to obtain a VSC current mathematical model under a synchronous rotation dq coordinate system:
wherein idThe component of the alternating side current on the d axis under the d-q coordinate system is shown; i.e. iqThe component of the alternating side current on the q axis under a d-q coordinate system is shown; t is time; rs+ronAn equivalent resistance for connecting the transformer and the reactor; omega is the angular frequency of an alternating current system; u. ofcdA control signal of a d axis of the VSC in a d-q coordinate system; u. ofcqA control signal of a q axis of the VSC under a d-q coordinate system; u. ofsdThe component of the alternating current power supply voltage on the d axis under the d-q coordinate system; u. ofsqIs the component of the alternating current power supply voltage on the q axis in the d-q coordinate system.
In this embodiment, in step S2, writing a standard state equation form for the current in the VSC current mathematical model, and obtaining the VSC inner ring current uncertainty dynamic model as:
wherein the content of the first and second substances,
a derivative with respect to time t of a system state vector; x (t) is a state vector at time t, where x is [ i ═ id iq]T(ii) a u (t) is a control input vector at time t, and u ═ ucd ucq]T；f0(t) a known perturbation vector at time t, said
Ls0A rated value which is the sum of the equivalent inductance of the coupling transformer and the reactor and the leakage inductance of the transformer; a (t) is a state matrix at time t, said stateState matrix
B (t) is a control matrix at time t
f (t) is an unknown perturbation vector at time t, f (t) ═ fd(t) fq(t)]T，fd(t) is the component of the unknown disturbance vector at the t moment on the d axis; f. ofq(t) is the component of the unknown disturbance vector at the time t on the q axis;
in this embodiment, fd(t) and fq(t) determined according to the following equation:
wherein, said Δ Ls＝Ls-Ls0，id(t) is the component of the alternating side current on the d axis under the d-q coordinate system at the time t; said Δ Rs＝Rs-Rs0，Rs0A rated value for an equivalent resistance of the link transformer; the delta ron＝ron-ron0，ron0A rated value of a switching loss connecting the transformer and the reactor; i.e. iq(t) is the component of the alternating side current on the q axis under the d-q coordinate system at the time t; u. ofsd(t) is the component of the alternating current power supply voltage on the d axis under the d-q coordinate system at the moment t; u. ofcd(t) is a d-axis control signal of the VSC under a d-q coordinate system at the moment t; sigmad(t) is the lumped uncertainty and disturbance of the d-axis at time t; sigmaq(t) is the lumped uncertainty and disturbance of the q axis at the time t; i.e. iq(t) is the component of the alternating side current on the q axis under the d-q coordinate system at the time t; u. ofsq(t) is the component of the voltage of the alternating current power supply on the q axis under the d-q coordinate system at the moment t; u. ofcqAnd (t) is a control signal of a q axis of the VSC under a d-q coordinate system at the time t.
In this embodiment, a filter decoupling first-order system with a bandwidth of α is selected, and the VSC inner loop current indeterminate dynamic model is processed to obtain the VSC inner loop current reference model based on the indeterminate interference estimation as follows:
wherein the content of the first and second substances,
is the reference state vector at time t; x is the number ofm(t) a reference state vector at time t, said xm(t)＝[idm iqm]T，idmIs in the reference model idA state vector of (a); i.e. iqmIs in the reference model iqA state vector of (a); u. ofm(t) is a system reference instruction at time t, um(t)＝[ucd ucq]T；AmIs a constant matrix, the
BmIs a constant matrix, the
Alpha is the bandwidth parameter of the filter;
in this embodiment, the error equation based on the uncertain interference estimation is as follows:
e(t)＝xm(t)-x(t)；
wherein e (t) is the state error at time t; x (t) is a state vector at time t, where x ═ id iq]T。
In this embodiment, the total parameterized uncertain dynamics and system external interference are listed:
σ(t)＝f0(t)+f(t)；
wherein σ (t) is lumped uncertainty and disturbance at the time t, and the lumped uncertainty and disturbance comprise terms of uncertainty dynamics, nonlinear dynamics and unknown disturbance; the above-mentioned
(t) fd(t)fq(t)]T；
Selecting a first order filter with a bandwidth of beta
And estimating sigma (t), wherein the uncertainty and disturbance estimation value are obtained by:
wherein the content of the first and second substances,
the estimated value of the lump uncertainty and disturbance at the time t; sigma (t) is the lump uncertainty and disturbance at the time t; gf(t) an uncertainty and disturbance estimation filter at time t;
in this embodiment, the step S4 specifically includes:
s41, determining an equation met by an inner loop current control law:
Bu(t)＝Amx(t)+Bmum(t)-Ax(t)-Ke(t)-(d0(t)+f(t))；
wherein K is an error feedback gain matrix; d0And (t) is a known disturbance vector at the time t.
S42, setting an unknown disturbance vector f (t) in an equation satisfied by the inner loop current control law as an uncertainty and disturbance estimation value, setting K to be 0, and obtaining a solution of the VSC inner loop current robust control law based on the uncertainty interference estimation through parameter transformation:
wherein the content of the first and second substances,
is an inverse laplace transform; s is a laplace operator; is a convolution symbol;
s43, parameter transformation is carried out on the solution of the robust control law of the VSC inner loop current based on the uncertain interference estimation, and the VSC physical quantity of the direct-current power distribution network is obtained:
wherein idrefIs a component i of the alternating side currentdA reference value of (d); i.e. iqrefIs a component i of the alternating side currentqTo the reference value of (c).
In order to verify the anti-interference capability and robustness of the VSC inner-loop current control method based on uncertain interference estimation, which is provided by the invention, for the direct-current bus voltage and the inner-loop current control, the traditional PI control and the control method are respectively adopted for the VSC inner-loop current control part, and simulation analysis is respectively carried out. The control effect on the bus direct-current voltage is respectively shown in the attached figures 4 and 5.
As is apparent from fig. 4 and 5, when the conventional PI control and the control of the present invention are applied to the inner loop current, the dc bus voltage can better track the desired dc bus reference voltage 780V, i.e. both have better tracking performance; for transient characteristics, at the time of 0.5s when the single-phase earth fault of the alternating current power supply end occurs and at the time of 0.55s when the fault is eliminated, in the two control methods, the recovery process of the voltage of the direct current bus to the voltage steady-state value shows higher response speed and has better anti-interference capability. It can be concluded that the system controlled by the invention has stronger anti-interference capability to the external disturbance of the system. Under the condition of ideal parameter setting, the influence can be eliminated to the greatest extent based on the method, the direct current bus voltage can be well controlled, and the system robustness is ensured.
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (8)
1. A VSC inner loop current control method based on uncertain interference estimation is characterized in that: the method comprises the following steps:
s1, constructing a VSC current mathematical model of a direct-current power distribution network;
s2, carrying out standardization processing on the current in the VSC current mathematical model to obtain a VSC inner ring current uncertain dynamic model;
s3, obtaining a VSC inner ring current reference model based on uncertain interference estimation, an error equation based on uncertain interference estimation, and uncertainty and disturbance estimation values based on a VSC inner ring current uncertain dynamic model;
and S4, calculating a control rule of the VSC inner ring current according to the VSC inner ring current reference model, the error equation and the uncertainty and disturbance estimation value.
2. The VSC inner loop current control method based on uncertain interference estimation of claim 1, wherein: in step S1, a VSC current mathematical model of the dc power distribution network is constructed, specifically including:
s11, determining a VSC alternating current side dynamic differential equation of the direct current distribution network:
wherein, Vsa、VsbAnd VscIs the three-phase voltage of an alternating current system; vta、VtbAnd VtcThe three-phase voltage at the VSC alternating current side; l issThe sum of the equivalent inductance of the connecting transformer and the reactor and the leakage inductance of the transformer; i.e. ia、ibAnd icThree-phase current of an alternating current system; t is time; rs+ronI represents an alternating-current side current for an equivalent resistance connecting the transformer and the reactor; rsIs an equivalent resistance connected with the transformer; r isonA switching loss for connecting the transformer and the reactor;
s12, carrying out coordinate transformation processing on the VSC alternating side dynamic differential equation to obtain a VSC current mathematical model:
wherein idThe component of the alternating side current on the d axis under the d-q coordinate system is shown; i.e. iqThe component of the alternating side current on the q axis under a d-q coordinate system is shown; t is time; rs+ronAn equivalent resistance for connecting the transformer and the reactor; omega is the angular frequency of an alternating current system; u. ofcdA control signal of a d axis of the VSC in a d-q coordinate system; u. ofcqA control signal of a q axis of the VSC under a d-q coordinate system; u. ofsdThe component of the alternating current power supply voltage on the d axis under the d-q coordinate system; u. ofsqIs the component of the alternating current power supply voltage on the q axis in the d-q coordinate system.
3. The VSC inner loop current control method based on uncertain interference estimation of claim 1, wherein: in step S2, the VSC inner loop current uncertain dynamic model is:
wherein the content of the first and second substances,
a derivative with respect to time t of a system state vector; x (t) is a state vector at time t, where x is [ i ═ id iq]T(ii) a u (t) is a control input vector at time t, and u ═ ucd ucq]T；f0(t) a known perturbation vector at time t, said
Ls0For coupling transformers and reactors, or the likeA rated value of a sum of an effective inductance and a transformer leakage inductance; a (t) is a state matrix at time t
B (t) is a control matrix at time t
f (t) is an unknown perturbation vector at time t, f (t) ═ fd(t) fq(t)]T，fd(t) is the component of the unknown disturbance vector at the t moment on the d axis; f. ofqAnd (t) is the component of the unknown disturbance vector at the time t on the q axis.
4. The VSC inner loop current control method based on uncertain interference estimation of claim 3, wherein: f isd(t) and fq(t) determined according to the following equation:
wherein, said Δ Ls＝Ls-Ls0，id(t) is the component of the alternating side current on the d axis under the d-q coordinate system at the time t; said Δ Rs＝Rs-Rs0，Rs0A rated value for an equivalent resistance of the link transformer; the delta ron＝ron-ron0，ron0A rated value of a switching loss connecting the transformer and the reactor; i.e. iq(t) is the component of the alternating side current on the q axis under the d-q coordinate system at the time t; u. ofsd(t) is the component of the alternating current power supply voltage on the d axis under the d-q coordinate system at the moment t; u. ofcd(t) is a d-axis control signal of the VSC under a d-q coordinate system at the moment t; sigmad(t) is the lumped uncertainty and disturbance of the d-axis at time t; sigmaq(t) is the lumped uncertainty and disturbance of the q axis at the time t; i.e. iq(t) is the component of the alternating side current on the q axis under the d-q coordinate system at the time t; u. ofsq(t) is a d-q coordinate system at the time of tA component of the supply voltage on the q-axis; u. ofcqAnd (t) is a control signal of a q axis of the VSC under a d-q coordinate system at the time t.
5. The VSC inner loop current control method based on uncertain interference estimation of claim 1, wherein: the VSC inner ring current reference model based on the uncertain interference estimation is as follows:
wherein the content of the first and second substances,
is the reference state vector at time t; x is the number ofm(t) a reference state vector at time t, said xm(t)＝[idmiqm]T，idmIs in the reference model idA state vector of (a); i.e. iqmIs in the reference model iqA state vector of (a); u. ofm(t) is a system reference instruction at time t, um(t)＝[ucd ucq]T；AmIs a constant matrix, the
BmIs a constant matrix, the
Alpha is the bandwidth parameter of the filter.
6. The VSC inner loop current control method based on uncertain interference estimation of claim 1, wherein: the error equation based on uncertain interference estimation is:
e(t)＝xm(t)-x(t)；
wherein e (t) is the state error at time t; x (t) is a state vector at time t, where x ═ id iq]T。
7. The VSC inner loop current control method based on uncertain interference estimation of claim 1, wherein: the uncertainty and disturbance estimate is:
wherein the content of the first and second substances,
the estimated value of the lump uncertainty and disturbance at the time t; sigma (t) is the lump uncertainty and disturbance at the time t; gfAnd (t) is an uncertainty and disturbance estimation filter at the time t.
8. The VSC inner loop current control method based on uncertain interference estimation of claim 1, wherein: the step S4 specifically includes:
s41, determining an equation met by an inner loop current control law:
Bu(t)＝Amx(t)+Bmum(t)-Ax(t)-Ke(t)-(d0(t)+f(t))；
wherein K is an error feedback gain matrix; d0(t) is the known perturbation vector at time t;
s42, solving an equation which is satisfied by the inner loop current control law to obtain a solution of the VSC inner loop current robust control law based on uncertain interference estimation:
wherein the content of the first and second substances,
is an inverse laplace transform; s is a laplace operator; is a convolution symbol;
s43, parameter transformation is carried out on the solution of the robust control law of the VSC inner loop current based on the uncertain interference estimation, and the VSC physical quantity of the direct-current power distribution network is obtained:
wherein idrefIs a component i of the alternating side currentdA reference value of (d); i.e. iqrefIs a component i of the alternating side currentqTo the reference value of (c).
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| CN116317744A (en) * | 2023-03-20 | 2023-06-23 | 南京航空航天大学 | Three-stage generator voltage regulating method based on second-order filter UDE |
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