CN112186779A - Parameter optimization method and device for double-fed wind generating set controller - Google Patents

Parameter optimization method and device for double-fed wind generating set controller Download PDF

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CN112186779A
CN112186779A CN202010958464.9A CN202010958464A CN112186779A CN 112186779 A CN112186779 A CN 112186779A CN 202010958464 A CN202010958464 A CN 202010958464A CN 112186779 A CN112186779 A CN 112186779A
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power grid
wind power
connected system
doubly
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迟永宁
李琰
田新首
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State Grid Corp of China SGCC
China Electric Power Research Institute Co Ltd CEPRI
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State Grid Corp of China SGCC
China Electric Power Research Institute Co Ltd CEPRI
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • 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
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • 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
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects

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Abstract

The invention provides a parameter optimization method and device for a double-fed wind generating set controller, which are used for determining whether a wind power grid-connected system generates subsynchronous oscillation or not based on equivalent impedance of a double-fed wind generating set and equivalent impedance of a power grid side; when the wind power grid-connected system generates subsynchronous oscillation, the closed-loop pole sensitivity of the wind power grid-connected system is determined based on the characteristic circuit of the wind power grid-connected system, the parameters of the doubly-fed wind generating set controller are optimized based on the closed-loop pole sensitivity, parameter optimization is realized through the closed-loop pole sensitivity, the parameter adaptability is strong, and the anti-interference capability of the wind power grid-connected system is improved; according to the method, the closed loop pole stability criterion is determined through the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side, the voltage and current of the wind turbine generator after subsynchronous oscillation of the wind power grid-connected system and the component of subsynchronous/supersynchronous frequency in the output power can be effectively inhibited, and the operation stability of the wind power grid-connected system is greatly improved.

Description

Parameter optimization method and device for double-fed wind generating set controller
Technical Field
The invention relates to the technical field of new energy, in particular to a method and a device for optimizing parameters of a double-fed wind generating set controller.
Background
A Double-Fed wind turbine Generator (DFIG) is a wound Induction Generator, a stator winding of a Double-Fed asynchronous Generator is directly connected with a power grid, a rotor winding is connected with the power grid through a frequency converter, the frequency, the voltage, the amplitude and the phase of a rotor winding power supply are automatically adjusted by the frequency converter according to operation requirements, the Generator can realize constant-frequency power generation at different rotating speeds, and the requirements of power loads and grid connection are met. Because the alternating current excitation is adopted, the generator and the power system form flexible connection, namely, the excitation current can be adjusted according to the voltage and the current of a power grid and the rotating speed of the generator, and the output voltage of the generator can be accurately adjusted to meet the requirement. The double-fed wind driven generator has the advantages that: 1. the reactive power can be controlled, and the active power and the reactive power are controlled by independently controlling the rotor exciting current decoupling. 2. Without being excited from the grid, but from the rotor circuit. 3. Reactive power can be generated and can be transmitted to the stator via the grid-side converter.
With the continuous expansion of the scale of grid-connected wind power, a wind power grid-connected system based on a power electronic technology faces severe oscillation. At present, the oscillation problem of a wind power grid-connected system is generally solved by adopting additional damping control and a control measure based on an equivalent circuit damping stability criterion, the method can only analyze a specific electric circuit, and if the input and the output of the equivalent system cannot form a circuit relation, the damping stability criterion cannot be applied to design, so that the existing control method has poor parameter adaptability and poor stability of the wind power grid-connected system, and the anti-interference capability is poor.
Disclosure of Invention
In order to overcome the defect of poor anti-interference capability of a wind power grid-connected system in the prior art, the invention provides a parameter optimization method of a double-fed wind generating set controller, which comprises the following steps:
determining whether the wind power grid-connected system generates subsynchronous oscillation or not based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
when the wind power grid-connected system generates subsynchronous oscillation, the closed-loop pole sensitivity of the wind power grid-connected system is determined based on the characteristic circuit of the wind power grid-connected system, and the parameters of the doubly-fed wind generator set controller are optimized based on the closed-loop pole sensitivity.
The method for determining whether subsynchronous oscillation occurs in the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side comprises the following steps:
determining equivalent impedance of the doubly-fed wind turbine generator based on equivalent impedance of a rotor-side converter considering a current inner loop, and determining equivalent impedance of a power grid side based on total inductance of the power grid side including a transformer and line inductance;
determining a transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
determining a closed loop pole of the wind power grid-connected system based on the transfer function;
and when the real part of the closed loop pole is positive, determining that the wind power grid-connected system generates subsynchronous oscillation.
The equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the system are as follows:
Figure BDA0002679532170000021
in the formula, Zdfig(s) is equivalent impedance of the doubly-fed wind turbine generator, Znet(s) is the equivalent impedance of the power grid side, s is a complex variable, RsIs the stator resistance, R, of a doubly-fed wind turbinerIs the rotor resistance, L, of a doubly-fed wind turbinesFor stator leakage inductance, LrFor rotor leakage inductance, GPLL(s) is the phase-locked loop frequency domain transfer function, σ2Is slip, Zrsc(s) rotor-side converter equivalent impedance considering the current inner loop, IrFor rotor current, UrThe rotor voltage is used, R is the total line resistance, L is the total grid side inductance including the transformer and the line inductance, and C is the line series compensation capacitance.
The method for determining the transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side comprises the following steps:
determining an equivalent circuit of the wind power grid-connected system based on a topological structure of the wind power grid-connected system;
determining a voltage equation of the wind power grid-connected system based on the equivalent circuit;
and determining a transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator, the equivalent impedance of the power grid side and a voltage equation corresponding to an equivalent circuit of the wind power grid-connected system.
The equivalent circuit comprises a wind power field side part and a power grid side part, wherein the wind power field side part comprises an ideal current source and a double-fed wind turbine equivalent impedance which are connected in parallel, and the power grid side part comprises a system equivalent voltage source and a system equivalent impedance which are connected in series.
The voltage equation of the wind power grid-connected system is as follows:
(I(s)-Ii(s))Zdfig(s)+I(s)Znet(s)＝-Usys(s)
in the formula, s is a complex variable, I(s) is the current of the wind power grid-connected system, Ii(s) is the current of an ideal current source, UsysAnd(s) is the voltage of the system equivalent voltage source.
The transfer function of the wind power grid-connected system is as follows:
Figure BDA0002679532170000022
wherein G(s) is a transfer function of the wind power grid-connected system, lambdaiIs the ith closed-loop pole, RiAnd m is a constant term, and n is the number of closed-loop poles.
The method for determining the closed loop pole sensitivity of the wind power grid-connected system based on the characteristic equation of the wind power grid-connected system comprises the following steps:
determining a characteristic equation of the wind power grid-connected system based on an equivalent circuit of the wind power grid-connected system;
and respectively deriving parameters of a closed-loop pole and a doubly-fed wind generator set controller based on the characteristic equation of the wind power grid-connected system to obtain the sensitivity of the closed-loop pole of the wind power grid-connected system.
The characteristic equation of the wind power grid-connected system is as follows:
Figure BDA0002679532170000031
in the formula, H (lambda)iK) is the characteristic equation at the closed-loop pole, Znet(λiK) is the grid-side equivalent impedance at the closed-loop pole, Zdfig(λiAnd K) is equivalent impedance of the doubly-fed wind generator set at the closed-loop pole point, and K is a controller parameter of the doubly-fed wind generator set.
The closed loop pole sensitivity of the wind power grid-connected system is as follows:
Figure BDA0002679532170000032
in the formula, S2K(λiK) closed-loop pole sensitivity, Delta lambda, for wind power grid systemsiIs the deviation of the closed loop poles, delta K is the deviation of the doubly fed wind generator set controller parameters, H'K(λiK) is H (lambda)iK) derivative of K, H'λi(λiK) is H (lambda)iK) to λiDerivative of, Z'sysK(λiAnd K) is the derivative of the equivalent impedance of the wind power grid-connected system at the closed-loop pole point to K.
The optimizing the parameters of the doubly-fed wind generating set controller based on the closed-loop pole sensitivity comprises the following steps:
taking the controller parameter of the doubly-fed wind generating set corresponding to the maximum real part absolute value of the closed-loop pole sensitivity as an optimization object;
and aiming at an optimization object, when the real part of the closed-loop pole sensitivity is positive, reducing the parameters of the doubly-fed wind generating set controller, and when the real part of the closed-loop pole sensitivity is negative, increasing the parameters of the doubly-fed wind generating set controller.
On the other hand, the invention also provides a parameter optimization device of the double-fed wind generating set controller, which comprises the following steps:
the determining module is used for determining whether the wind power grid-connected system generates subsynchronous oscillation or not based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
and the optimization module is used for determining the closed-loop pole sensitivity of the wind power grid-connected system based on the characteristic circuit of the wind power grid-connected system when the wind power grid-connected system generates subsynchronous oscillation, and optimizing the parameters of the double-fed wind generating set controller based on the closed-loop pole sensitivity.
The technical scheme provided by the invention has the following beneficial effects:
in the parameter optimization method of the double-fed wind generating set controller, whether the wind power grid-connected system generates subsynchronous oscillation is determined based on the equivalent impedance of the double-fed wind generating set and the equivalent impedance of the power grid side; when the wind power grid-connected system generates subsynchronous oscillation, the closed-loop pole sensitivity of the wind power grid-connected system is determined based on the characteristic circuit of the wind power grid-connected system, the parameters of the doubly-fed wind generating set controller are optimized based on the closed-loop pole sensitivity, parameter optimization is realized through the closed-loop pole sensitivity, the parameter adaptability is strong, and the anti-interference capability of the wind power grid-connected system is improved;
according to the method, the closed-loop pole stability criterion is determined through the equivalent impedance of the double-fed wind turbine generator and the equivalent impedance of the power grid side, and a basis is provided for the optimization of parameters of the double-fed wind turbine generator controller;
the technical scheme provided by the invention can effectively inhibit subsynchronous/supersynchronous frequency components in the voltage, current and output power of the wind turbine generator after subsynchronous oscillation of the wind power grid-connected system, and greatly improves the operation stability of the wind power grid-connected system.
Drawings
Fig. 1 is a flowchart of a parameter optimization method for a doubly-fed wind turbine generator set controller according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an equivalent circuit of a wind power integration system in the embodiment of the invention;
FIG. 3 is a schematic diagram illustrating a variation trend of a pole of a closed loop when a current inner loop scaling factor is 0.6 according to an embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating a variation trend of a closed loop pole when a current inner loop scaling factor is 0.5 according to an embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating a variation trend of a pole of a closed loop when a current inner loop scaling factor is 0.4 according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Example 1
The embodiment 1 of the invention provides a method for optimizing parameters of a doubly-fed wind generating set controller, a specific flow chart is shown in fig. 1, and the specific process is as follows:
s101: determining whether the wind power grid-connected system generates subsynchronous oscillation or not based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
s102: when the wind power grid-connected system generates subsynchronous oscillation, the closed-loop pole sensitivity of the wind power grid-connected system is determined based on the characteristic circuit of the wind power grid-connected system, and the parameters of the doubly-fed wind generator set controller are optimized based on the closed-loop pole sensitivity.
Whether the wind power grid-connected system has subsynchronous oscillation or not is determined based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side, and the method comprises the following steps:
determining equivalent impedance of the doubly-fed wind turbine generator based on equivalent impedance of a rotor-side converter considering a current inner loop, and determining equivalent impedance of a power grid side based on total inductance of the power grid side including a transformer and line inductance;
determining a transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
determining a closed loop pole of the wind power grid-connected system based on the transfer function;
and when the real part of the closed loop pole is positive, determining that the wind power grid-connected system generates subsynchronous oscillation.
The equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the system are as follows:
Figure BDA0002679532170000051
in the formula, Zdfig(s) is equivalent impedance of the doubly-fed wind turbine generator, Znet(s) is the grid sideEquivalent impedance, s is a complex variable, RsIs the stator resistance, R, of a doubly-fed wind turbinerIs the rotor resistance, L, of a doubly-fed wind turbinesFor stator leakage inductance, LrFor rotor leakage inductance, GPLL(s) is the phase-locked loop frequency domain transfer function, σ2Is slip, Zrsc(s) rotor-side converter equivalent impedance considering the current inner loop, IrFor rotor current, UrThe rotor voltage is used, R is the total line resistance, L is the total grid side inductance including the transformer and the line inductance, and C is the line series compensation capacitance.
The method for determining the transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side comprises the following steps:
determining an equivalent circuit of the wind power grid-connected system based on a topological structure of the wind power grid-connected system;
determining a voltage equation of the wind power grid-connected system based on the equivalent circuit;
and determining a transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator, the equivalent impedance of the power grid side and a voltage equation corresponding to an equivalent circuit of the wind power grid-connected system.
An equivalent circuit of a wind power grid-connected system is shown in fig. 2, the equivalent circuit comprises a wind power field side part and a power grid side part, the wind power field side part comprises an ideal current source and a double-fed wind turbine equivalent impedance which are connected in parallel, the power grid side part comprises a system equivalent voltage source and a system equivalent impedance which are connected in series, namely the power grid side is represented by the power grid side equivalent impedance and the power grid side system equivalent voltage source, the wind power field side is represented by the ideal current source and the double-fed wind turbine equivalent impedance, in fig. 2, I is a current of the wind power gridiCurrent of ideal current source on wind farm side, ZnetIs the equivalent impedance of the grid side, ZdfigEquivalent impedance, U, of double-fed wind turbine generator at wind power plant sidesysThe voltage of the equivalent voltage source of the power grid side system.
The voltage equation of the wind power grid-connected system can be obtained from fig. 1, and is as follows:
(I(s)-Ii(s))Zdfig(s)+I(s)Znet(s)＝-Usys(s)
in the formula, s is a complex variable, I(s) is the current of the wind power grid-connected system, Ii(s) is the current of an ideal current source, UsysAnd(s) is the voltage of the system equivalent voltage source. The variables in the text with s each represent a physical quantity under a complex variable.
The expression of I(s) obtained from a voltage equation of the wind power grid-connected system is as follows:
Figure BDA0002679532170000061
the transfer function of the wind power grid-connected system can be obtained by the expression of I(s)
Figure BDA0002679532170000062
By combining the expression of the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the system, the transfer function can be expressed in the form of a closed loop pole and a reserved number, and the transfer function of the wind power grid-connected system as follows is obtained specifically:
Figure BDA0002679532170000063
wherein G(s) is a transfer function of the wind power grid-connected system, lambdaiFor the ith closed-loop pole, i.e. the system characteristic root, RiAnd m is a constant term, and n is the number of closed-loop poles.
λiExpressed as λ in real and imaginary formi＝αi+jωiWherein α isiIs λiReal part of, ωiIs λiImaginary part of, angular frequency ωi＝2πfi，fiIs the corresponding oscillation frequency.
Each closed-loop pole represents an oscillation mode of the wind power grid-connected system, and the amplitude and the phase of the oscillation mode are mainly influenced by the corresponding residue. The real part of the closed-loop pole is the damping coefficient and the imaginary part is the angular frequency determined by the oscillation frequency. Only when allWhen the closed loop poles are not located on the right half plane of the complex plane, the wind power grid-connected system is stable. If a certain lambdaiReal part of (a)iIf the frequency is positive, the occurrence frequency of the wind power grid-connected system is fiOtherwise, the oscillation indicates that the non-occurrence frequency of the wind power grid-connected system is fiIs oscillated.
The method for determining the closed loop pole sensitivity of the wind power grid-connected system based on the characteristic equation of the wind power grid-connected system comprises the following steps:
determining a characteristic equation of the wind power grid-connected system based on an equivalent circuit of the wind power grid-connected system;
and respectively deriving parameters of the closed-loop pole and the doubly-fed wind generator set controller based on a characteristic equation of the wind power grid-connected system to obtain the sensitivity of the closed-loop pole of the wind power grid-connected system.
The characteristic equation of the wind power grid-connected system is as follows:
Figure BDA0002679532170000064
in the formula, H (lambda)iK) is the characteristic equation at the closed-loop pole, Znet(λiK) is the grid-side equivalent impedance at the closed-loop pole, Zdfig(λiAnd K) is equivalent impedance of the doubly-fed wind generator set at the closed-loop pole point, and K is a controller parameter of the doubly-fed wind generator set.
The characteristic equation of the wind power grid-connected system is derived to obtain
Figure BDA0002679532170000065
H′K(λiK) is H (lambda)iThe derivative of K) to K,
Figure BDA0002679532170000079
is H (lambda)iK) to λiDerivative of (a), Δ λiAnd the delta K is the deviation of the parameters of the doubly-fed wind generating set controller.
According to H'λi(λi,K)Δλi+H′K(λiAnd K) delta K is 0 to obtain the wind power integration network with the following formulaClosed loop pole sensitivity of the system:
Figure BDA0002679532170000071
due to Zsys(li,K)＝Znet(li,K)+Zdifg(liK) to
Figure BDA0002679532170000072
So that Z can be obtainedsys(λiAnd K) is 0, and the residue is defined to obtain the residue corresponding to the ith closed-loop pole, which is specifically represented by the following formula:
Figure BDA0002679532170000073
further, the method can be obtained as follows:
Figure BDA0002679532170000074
bonding of
Figure BDA0002679532170000075
And
Figure BDA0002679532170000076
and is based on H'λi(λi,K)＝Z′sysλi(λiK) and H'K(λi,K)＝Z′sysK(λiAnd K), the closed loop pole sensitivity of the wind power grid-connected system can be obtained as follows:
Figure BDA0002679532170000077
in the formula, S2K(λiK) closed-loop pole sensitivity, Delta lambda, for wind power grid systemsiIs the deviation of the closed loop poles, delta K is the deviation of the doubly fed wind generator set controller parameters, H'K(λiK) is H (lambda)iThe derivative of K) to K,
Figure BDA00026795321700000710
is H (lambda)iK) to λiDerivative of, Z'sysK(λiAnd K) is the derivative of the equivalent impedance of the wind power grid-connected system at the closed-loop pole point to K.
S2K(λiAnd K) respectively represents the influence of the change of K in a small range on the real part, namely damping, and the imaginary part, namely the oscillation frequency of the pole of the closed loop. The real part and the imaginary part of the closed loop pole sensitivity are respectively as follows:
Figure BDA0002679532170000078
if S2KReIf the K is positive, it indicates that the closed loop pole moves towards the right half plane of the complex plane along with the increase of K, that is, the damping is reduced, which is not beneficial to the stability of the wind power grid-connected system;
if S2KReAnd if the voltage is negative, the closed loop pole is shown to move towards the left half plane of the complex plane, and the damping of the wind power grid-connected system is increased.
If S2KImPositive indicates that as K increases, the imaginary part of the closed loop pole moves upward and the frequency of oscillation increases;
if S2KImIf the amplitude value is negative, the oscillation frequency is reduced, and the influence degree of K on the oscillation mode of the wind power grid-connected system can also be judged according to the amplitude value of the sensitivity.
Optimizing the parameters of the doubly-fed wind generating set controller by using the closed-loop pole sensitivity, comprising the following steps:
taking the controller parameter of the doubly-fed wind generating set corresponding to the maximum real part absolute value of the closed-loop pole sensitivity as an optimization object;
and aiming at an optimization object, when the real part of the closed-loop pole sensitivity is positive, reducing the parameters of the doubly-fed wind generating set controller, and when the real part of the closed-loop pole sensitivity is negative, increasing the parameters of the doubly-fed wind generating set controller.
Example 2
An embodiment 2 of the present invention provides a parameter optimization apparatus for a doubly-fed wind turbine generator system controller, including:
the determining module is used for determining whether the wind power grid-connected system generates subsynchronous oscillation or not based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
and the optimization module is used for determining the closed-loop pole sensitivity of the wind power grid-connected system based on the characteristic circuit of the wind power grid-connected system when the wind power grid-connected system generates subsynchronous oscillation, and optimizing the parameters of the double-fed wind generating set controller based on the closed-loop pole sensitivity.
The determining module comprises:
the double-fed wind turbine generator system comprises a first determining unit, a second determining unit and a control unit, wherein the first determining unit is used for determining the equivalent impedance of a double-fed wind turbine generator system based on the equivalent impedance of a rotor-side converter considering a current inner loop and determining the equivalent impedance of a power grid side based on the total power grid side inductance including a transformer and line inductance;
the second determination unit is used for determining a transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
the third determining unit is used for determining a closed loop pole of the wind power grid-connected system based on the transfer function;
and the fourth determining unit is used for determining that the sub-synchronous oscillation occurs to the wind power grid-connected system when the real part of the closed loop pole is positive.
The first determining unit determines the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the system according to the following formula:
Figure BDA0002679532170000081
in the formula, Zdfig(s) is equivalent impedance of the doubly-fed wind turbine generator, Znet(s) is the equivalent impedance of the power grid side, s is a complex variable, RsIs the stator resistance, R, of a doubly-fed wind turbinerIs the rotor resistance, L, of a doubly-fed wind turbinesFor stator leakage inductance, LrFor rotor leakage inductance, GPLL(s) is the phase-locked loop frequency domain transfer function, σ2Is slip, Zrsc(s) rotor-side converter equivalent impedance considering the current inner loop, IrFor rotor current, UrThe rotor voltage is used, R is the total line resistance, L is the total grid side inductance including the transformer and the line inductance, and C is the line series compensation capacitance.
The second determining unit is specifically configured to:
determining an equivalent circuit of the wind power grid-connected system based on a topological structure of the wind power grid-connected system;
determining a voltage equation of the wind power grid-connected system based on the equivalent circuit;
and determining a transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator, the equivalent impedance of the power grid side and a voltage equation corresponding to an equivalent circuit of the wind power grid-connected system.
The equivalent circuit comprises a wind power plant side part and a power grid side part;
the wind power plant side part comprises an ideal current source and a double-fed wind turbine generator equivalent impedance which are connected in parallel, and the power grid side part comprises a system equivalent voltage source and a system equivalent impedance which are connected in series.
The second determining unit determines a voltage equation of the wind power grid-connected system according to the following formula:
(I(s)-Ii(s))Zdfig(s)+I(s)Znet(s)＝-Usys(s)
in the formula, s is a complex variable, I(s) is the current of the wind power grid-connected system, Ii(s) is the current of an ideal current source, UsysAnd(s) is the voltage of the system equivalent voltage source.
The second determining unit determines a transfer function of the wind power grid-connected system according to the following formula:
Figure BDA0002679532170000091
wherein G(s) is a transfer function of the wind power grid-connected system, lambdaiIs the ith closed-loop pole, RiAnd m is a constant term, and n is the number of closed-loop poles.
The optimization module includes a fifth determination unit, and the fifth determination unit is specifically configured to:
determining a characteristic equation of the wind power grid-connected system based on an equivalent circuit of the wind power grid-connected system;
and respectively deriving parameters of the closed-loop pole and the doubly-fed wind generator set controller based on a characteristic equation of the wind power grid-connected system to obtain the sensitivity of the closed-loop pole of the wind power grid-connected system.
The fifth determining unit determines a characteristic equation of the wind power grid-connected system according to the following formula:
Figure BDA0002679532170000092
in the formula, H (lambda)iK) is the characteristic equation at the closed-loop pole, Znet(λiK) is the grid-side equivalent impedance at the closed-loop pole, Zdfig(λiAnd K) is equivalent impedance of the doubly-fed wind generator set at the closed-loop pole point, and K is a controller parameter of the doubly-fed wind generator set.
The fifth determining unit determines the closed-loop pole sensitivity of the wind power grid-connected system according to the following formula:
Figure BDA0002679532170000101
in the formula, S2K(λiK) closed-loop pole sensitivity, Delta lambda, for wind power grid systemsiIs the deviation of the closed loop poles, delta K is the deviation of the doubly fed wind generator set controller parameters, H'K(λiK) is H (lambda)iThe derivative of K) to K,
Figure BDA0002679532170000103
is H (lambda)iK) to λiDerivative of, Z'sysK(λiAnd K) is the derivative of the equivalent impedance of the wind power grid-connected system at the closed-loop pole point to K.
The optimization module comprises an optimization unit, and the optimization unit is specifically used for:
taking the controller parameter of the doubly-fed wind generating set corresponding to the maximum real part absolute value of the closed-loop pole sensitivity as an optimization object;
and aiming at an optimization object, when the real part of the closed-loop pole sensitivity is positive, reducing the parameters of the doubly-fed wind generating set controller, and when the real part of the closed-loop pole sensitivity is negative, increasing the parameters of the doubly-fed wind generating set controller.
Example 3
The embodiment 3 of the invention provides a parameter optimization method for a double-fed wind generating set controller, which uses a 100MVA double-fed wind power plant model and a line series compensation degree kLThe setting was 16.66%. When the wind power grid-connected system operates in a steady state, the rotor rotating speed frequency f of the doubly-fed wind turbine generatorrThe active power P emitted by the wind power plant is 0.9pu and the reactive power Q emitted by the wind power plant is 0 at 60 Hz. When the series compensation capacitor in the power transmission line is put into use, the generation frequency of the system is about 15.5Hz (namely fer15.5 Hz). At kLUnder the series compensation degree, subsynchronous oscillation of the wind power grid-connected system is unstable, and the k of the wind power grid-connected system can be calculated according to the closed-loop pole sensitivityLThe wind generating set controller parameter sensitivity at the series compensation degree is shown in table 1.
TABLE 1
Figure BDA0002679532170000102
In the table 1, a sub-synchronous oscillation mode, S ', based on a wind power grid-connected system'21Is a closed loop pole to RSC current inner loop proportionality coefficient Kp2Sensitivity of (2), S'22Is a closed loop pole to RSC current inner loop proportionality coefficient Ki2Sensitivity of (2), S'23Controlling parameter K for PLL for closed-loop pole pairppSensitivity of (2), S'24Controlling parameter K for PLL for closed-loop pole pairpiThe sensitivity of (2).
According to the table 1, the closed loop pole sensitivity of the wind power grid-connected system subsynchronous oscillation mode can be known, and the damping of the wind power grid-connected system is mainly influenced by the RSC current inner loop proportionality coefficient Kp2，Kp2The closed loop pole of the subsynchronous oscillation mode of the wind power grid-connected system moves to the right half part of the complex plane, namely the damping of the wind power grid-connected system is reduced, so that the K can be reducedp2The subsynchronous oscillation of the wind power grid-connected system is restrained by the measure (2).
Further combining with the stability criterion of the closed loop pole of the equivalent system to adjust Kp2The value of (A) is as follows: in original Kp2On the basis of the value, K is properly reducedp2The obtained current inner ring proportion coefficients of the wind power grid-connected system respectively take the change trends of the closed loop poles of 0.6, 0.5 and 0.4, as shown in fig. 3-5. As can be seen from FIGS. 3 to 5, Kp2The main influence of the change of (2) is the damping of the wind power grid-connected system, and the influence on the frequency of the subsynchronous oscillation mode is small; kp2When the value of (1) is 0.6, the real part of the closed loop pole is positive, which indicates that the wind power grid-connected system can generate unstable subsynchronous oscillation with the frequency of about 15.3 Hz; reduction of Kp2When the value is 0.5, the pole of the closed loop moves to the left half plane, although the equivalent damping of the wind power grid-connected system is increased, the real part of the equivalent damping is near a zero value, and the wind power grid-connected system still has the risk of divergent oscillation; reduction of Kp2And after the value is 0.4, the pole of the closed loop continuously moves to the left half plane, and the real part of the pole is less than zero, which indicates that the wind power grid-connected system is stable.
From the angle analysis of ensuring the stability of the subsynchronous oscillation of the wind power integration system, Kp2The value of K is less than 0.5, namely the closed loop pole of the subsynchronous oscillation mode is positioned on the left half plane, but the RSC fast control characteristic required by the normal operation of the wind power grid-connected system is considered, and K isp2Should not be too small, so this embodiment 3 will use Kp2The value of (A) is 0.4.
For convenience of description, each part of the above apparatus is separately described as being functionally divided into various modules or units. Of course, the functionality of the various modules or units may be implemented in the same one or more pieces of software or hardware when implementing the present application.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only intended to illustrate the technical solution of the present invention and not to limit the same, and a person of ordinary skill in the art can make modifications or equivalent substitutions to the specific embodiments of the present invention with reference to the above embodiments, and any modifications or equivalent substitutions which do not depart from the spirit and scope of the present invention are within the protection scope of the present invention as claimed in the appended claims.

Claims (12)

1. A method for optimizing parameters of a doubly-fed wind generating set controller is characterized by comprising the following steps:
determining whether the wind power grid-connected system generates subsynchronous oscillation or not based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
when the wind power grid-connected system generates subsynchronous oscillation, the closed-loop pole sensitivity of the wind power grid-connected system is determined based on the characteristic circuit of the wind power grid-connected system, and the parameters of the doubly-fed wind generator set controller are optimized based on the closed-loop pole sensitivity.
2. The parameter optimization method for the doubly-fed wind generator set controller according to claim 1, wherein the determining whether subsynchronous oscillation occurs in the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind generator set and the equivalent impedance of the grid side comprises:
determining equivalent impedance of the doubly-fed wind turbine generator based on equivalent impedance of a rotor-side converter considering a current inner loop, and determining equivalent impedance of a power grid side based on total inductance of the power grid side including a transformer and line inductance;
determining a transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
determining a closed loop pole of the wind power grid-connected system based on the transfer function;
and when the real part of the closed loop pole is positive, determining that the wind power grid-connected system generates subsynchronous oscillation.
3. The method for optimizing the parameters of the doubly-fed wind generator set controller according to claim 2, wherein the equivalent impedance of the doubly-fed wind generator set and the equivalent impedance of the system are as follows:
Figure FDA0002679532160000011
in the formula, Zdfig(s) is equivalent impedance of the doubly-fed wind turbine generator, Znet(s) is the equivalent impedance of the power grid side, s is a complex variable, RsIs the stator resistance, R, of a doubly-fed wind turbinerIs the rotor resistance, L, of a doubly-fed wind turbinesFor stator leakage inductance, LrFor rotor leakage inductance, GPLL(s) is the phase-locked loop frequency domain transfer function, σ2Is slip, Zrsc(s) rotor-side converter equivalent impedance considering the current inner loop, IrFor rotor current, UrThe rotor voltage is used, R is the total line resistance, L is the total grid side inductance including the transformer and the line inductance, and C is the line series compensation capacitance.
4. The method for optimizing the parameters of the doubly-fed wind generator set controller according to claim 3, wherein the determining the transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind generator set and the equivalent impedance of the grid side comprises:
determining an equivalent circuit of the wind power grid-connected system based on a topological structure of the wind power grid-connected system;
determining a voltage equation of the wind power grid-connected system based on the equivalent circuit;
and determining a transfer function of the wind power grid-connected system based on the equivalent impedance of the doubly-fed wind turbine generator, the equivalent impedance of the power grid side and a voltage equation corresponding to an equivalent circuit of the wind power grid-connected system.
5. The doubly-fed wind generator set controller parameter optimization method of claim 4, wherein said equivalent circuit comprises a wind farm side portion and a grid side portion;
the wind power plant side part comprises an ideal current source and a double-fed wind turbine generator equivalent impedance which are connected in parallel, and the power grid side part comprises a system equivalent voltage source and a system equivalent impedance which are connected in series.
6. The parameter optimization method for the doubly-fed wind generator set controller according to claim 4, wherein a voltage equation of the wind power grid-connected system is as follows:
(I(s)-Ii(s))Zdfig(s)+I(s)Znet(s)＝-Usys(s)
in which s is a complex variableI(s) is the current of the wind power grid system, Ii(s) is the current of an ideal current source, UsysAnd(s) is the voltage of the system equivalent voltage source.
7. The method of claim 4, wherein the transfer function of the wind power grid-connected system is as follows:
Figure FDA0002679532160000021
wherein G(s) is a transfer function of the wind power grid-connected system, lambdaiIs the ith closed-loop pole, RiAnd m is a constant term, and n is the number of closed-loop poles.
8. The method of claim 7, wherein the determining the closed-loop pole sensitivity of the wind power grid-connected system based on the characteristic equation of the wind power grid-connected system comprises:
determining a characteristic equation of the wind power grid-connected system based on an equivalent circuit of the wind power grid-connected system;
and respectively deriving parameters of a closed-loop pole and a doubly-fed wind generator set controller based on the characteristic equation of the wind power grid-connected system to obtain the sensitivity of the closed-loop pole of the wind power grid-connected system.
9. The method of claim 8, wherein the characteristic equation of the wind power grid-connected system is as follows:
Figure FDA0002679532160000022
in the formula, H (lambda)iK) is the characteristic equation at the closed-loop pole, Znet(λiK) is the grid-side equivalent impedance at the closed-loop pole, Zdfig(λiAnd K) is equivalent impedance of the doubly-fed wind generator set at the closed-loop pole point, and K is a controller parameter of the doubly-fed wind generator set.
10. The method of claim 9, wherein the closed-loop pole sensitivity of the wind grid system is as follows:
Figure FDA0002679532160000023
in the formula, S2K(λiK) closed-loop pole sensitivity, Delta lambda, for wind power grid systemsiIs the deviation of the closed loop poles, delta K is the deviation of the doubly fed wind generator set controller parameters, H'K(λiK) is H (lambda)iK) derivative of K, H'λi(λiK) is H (lambda)iK) to λiDerivative of, Zs′ysK(λiAnd K) is the derivative of the equivalent impedance of the wind power grid-connected system at the closed-loop pole point to K.
11. The doubly-fed wind generator set controller parameter optimization method of claim 8, wherein the optimizing doubly-fed wind generator set controller parameters based on the closed-loop pole sensitivity comprises:
taking the controller parameter of the doubly-fed wind generating set corresponding to the maximum real part absolute value of the closed-loop pole sensitivity as an optimization object;
and aiming at an optimization object, when the real part of the closed-loop pole sensitivity is positive, reducing the parameters of the doubly-fed wind generating set controller, and when the real part of the closed-loop pole sensitivity is negative, increasing the parameters of the doubly-fed wind generating set controller.
12. A doubly-fed wind generating set controller parameter optimization device is characterized by comprising:
the determining module is used for determining whether the wind power grid-connected system generates subsynchronous oscillation or not based on the equivalent impedance of the doubly-fed wind turbine generator and the equivalent impedance of the power grid side;
and the optimization module is used for determining the closed-loop pole sensitivity of the wind power grid-connected system based on the characteristic circuit of the wind power grid-connected system when the wind power grid-connected system generates subsynchronous oscillation, and optimizing the parameters of the double-fed wind generating set controller based on the closed-loop pole sensitivity.
CN202010958464.9A 2020-09-14 2020-09-14 Parameter optimization method and device for double-fed wind generating set controller Pending CN112186779A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113221367A (en) * 2021-05-21 2021-08-06 中国电力科学研究院有限公司 Method and device for judging stability of power electronic power supply area
CN115378054A (en) * 2021-07-19 2022-11-22 上海交通大学 Hybrid control type full-power conversion wind turbine generator
CN115528954A (en) * 2021-06-25 2022-12-27 中国农业大学 Method and system for setting control parameters of double-fed wind power generation system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113221367A (en) * 2021-05-21 2021-08-06 中国电力科学研究院有限公司 Method and device for judging stability of power electronic power supply area
CN115528954A (en) * 2021-06-25 2022-12-27 中国农业大学 Method and system for setting control parameters of double-fed wind power generation system
CN115528954B (en) * 2021-06-25 2024-06-11 中国农业大学 Control parameter setting method and system for doubly-fed wind power generation system
CN115378054A (en) * 2021-07-19 2022-11-22 上海交通大学 Hybrid control type full-power conversion wind turbine generator
CN115378054B (en) * 2021-07-19 2023-10-24 上海交通大学 Hybrid control type full-power conversion wind turbine generator system

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