CN116613819A - Wind power grid-connected system self-adaptive transient stability control method and device based on angular frequency offset, storage medium and equipment - Google Patents

Wind power grid-connected system self-adaptive transient stability control method and device based on angular frequency offset, storage medium and equipment Download PDF

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Publication number
CN116613819A
CN116613819A CN202310686464.1A CN202310686464A CN116613819A CN 116613819 A CN116613819 A CN 116613819A CN 202310686464 A CN202310686464 A CN 202310686464A CN 116613819 A CN116613819 A CN 116613819A
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power grid
phase
angular frequency
wind power
locked loop
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Inventor
崔晓丹
吴家龙
陈燕东
罗聪
谢志为
许剑冰
邓馗
王彦品
冯佳期
刘小可
刘玉城
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Hunan University
NARI Group Corp
Nari Technology Co Ltd
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Hunan University
NARI Group Corp
Nari Technology Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H02J3/241—The oscillation concerning frequency
    • 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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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention discloses a wind power grid-connected system self-adaptive transient stability control method, device, storage medium and equipment based on angular frequency offset. In different fault depths, the virtual voltage component can adjust the virtual electromagnetic torque of the wind power grid-connected system, remodel the synchronous characteristic of the phase-locked loop, and self-adaptively offset the unbalance of the synchronous torque, so that the wind power grid-connected system can automatically search for a balance point in the transient process, and the transient stability of the wind power grid-connected system is effectively enhanced. The invention does not need to add hardware equipment, is not limited by factors such as disturbance type, system parameters, converter capacity and the like, and has strong self-adaptive capacity.

Description

Wind power grid-connected system self-adaptive transient stability control method and device based on angular frequency offset, storage medium and equipment
Technical Field
The invention relates to a wind power grid-connected system self-adaptive transient stability control method, device, storage medium and equipment based on angular frequency deviation, and belongs to the technical field of transient stability in new energy power generation.
Background
With the rapid development of new energy power generation technology, the installed capacity of new energy in an electric power system represented by wind power is continuously increased. However, since the distribution of wind energy resources is opposite to the distribution of electricity loads, the wind power grid-connected system needs to perform large-scale long-distance transportation, which causes the grid to exhibit weak synchronous grid characteristics. When the power grid has short circuit fault, transient instability phenomenon of the wind power grid-connected system can occur during low voltage ride through, and serious threat is caused to safe and stable operation of the power system. Therefore, improving the transient stability of a wind power grid-connected system during grid faults is an important problem for current wind power development. However, the existing control strategy is limited by the capacity of the converter, so that the problem of transient stability of the wind power grid-connected system during faults is difficult to solve, and self-adaptive adjustment under transient conditions cannot be achieved.
Disclosure of Invention
The invention aims to provide a wind power grid-connected system self-adaptive transient stability control method, device, storage medium and equipment based on angular frequency offset, which are free from increasing equipment hardware, and are characterized in that a negative feedback loop is added into a phase-locked loop by changing a control structure of the phase-locked loop in the wind power grid-connected system, and the synchronous characteristic is remodeled by negatively feeding back the angular frequency offset to the input end of the phase-locked loop so as to improve the transient synchronous stability of the wind power grid-connected system during faults.
In order to solve the technical problems, the invention is realized by adopting the following technical scheme.
In a first aspect, the invention provides a wind power grid-connected system self-adaptive transient stability control method based on angular frequency offset, which comprises the following steps:
obtaining an angular frequency offset according to the output angular frequency of a phase-locked loop and the angular frequency of a power grid in the wind power grid-connected system;
according to the angular frequency offset, virtual voltage is obtained through a negative feedback loop preset in the phase-locked loop, and the virtual voltage is fed back to the input end of the phase-locked loop;
based on the virtual voltage self-adaptive control wind power grid-connected system, a phase-locked loop synchronization characteristic equation is remodeled, so that an inverter in the wind power grid-connected system is kept synchronous with a power grid in a transient process.
With reference to the first aspect, further, the negative feedback loop includes an integrating loop K/s, where K is a customized control parameter and s is a complex parameter.
With reference to the first aspect, further, the angular frequency offset Δω pll After passing through the integrating loop of the negative feedback loop, an additional virtual voltage DeltaU is generated tq And virtual voltage DeltaU tq Feedback to the input end of the phase-locked loop through virtual voltageΔU tq And (3) adaptively counteracting errors of an output phase angle of an inverter and a phase angle of a power grid in the wind power grid-connected system.
With reference to the first aspect, further, the reshaped phase-locked loop synchronization characteristic equation is as follows:
wherein J is v In order for the coefficient of rotational inertia to be the same,to use adaptive control of post virtual prime mover torque, T v To use the self-adaptive control to post-virtual electromagnetic torque, D v For damping coefficient, k p Is the proportional control coefficient of the phase-locked loop, L g For the grid-side inductance value, < >>Is d-axis current command value, k i For integrating control coefficients, ω, of the phase-locked loop pll For outputting angular frequency, omega for phase-locked loop g For the angular frequency of the power grid,for q-axis current command value, R g Is the line resistance, U g The delta is the angle difference between the grid voltage and the output voltage of the inverter, and K is the self-adaptive control parameter.
According to the remodeled phase-locked loop synchronous characteristic equation, the damping coefficient of the system is obviously increased after the self-adaptive transient control is adopted, and the system has stronger anti-interference performance and disturbance inhibition capability, so that the reliability and stability of the wind power grid-connected system are improved. More importantly, the introduction of the self-adaptive transient control, the virtual electromagnetic torque Tv is self-adaptively adjusted according to the angular frequency offset, so that the system has the capability of automatically searching a balance working point after suffering from large interference such as coincidence change, power grid fault and the like, and the synchronous characteristic with the power grid is maintained.
With reference to the first aspect, further, obtaining, by an iterative algorithm, an optimal value of the adaptive control parameter K includes:
initializing an adaptive control parameter K; solving by utilizing a second-order synchronous equation of a phase-locked loop through MATLAB command 'ode 45' to obtain a real-time power angle delta under the current self-adaptive control parameter; judging whether the power angle delta exceeds the set maximum overshoot delta max The method comprises the steps of carrying out a first treatment on the surface of the If delta > delta max Adding 0.01 to the self-adaptive control parameter, and recalculating the real-time power angle according to the updated self-adaptive control parameter K until delta is less than or equal to delta max The method comprises the steps of carrying out a first treatment on the surface of the If delta is less than or equal to delta max The iteration is terminated, and the optimal value K of the adaptive control parameter K is output cr 。
According to the method, the adaptive control parameters are designed and optimized, so that better stage performance can be obtained, and progressive stability is realized.
In a second aspect, the present invention provides an adaptive transient stability control device for a wind power grid-connected system based on angular frequency offset, including:
the data acquisition module is used for obtaining an angular frequency offset according to the output angular frequency of the phase-locked loop and the angular frequency of the power grid in the wind power grid-connected system;
the negative feedback module is used for obtaining virtual voltage through a negative feedback loop preset in the phase-locked loop according to the angular frequency offset and feeding back the virtual voltage to the input end of the phase-locked loop;
the transient stability control module is used for adaptively controlling the wind power grid-connected system based on the virtual voltage, and remolding a phase-locked loop synchronization characteristic equation to enable an inverter in the wind power grid-connected system to keep synchronization with a power grid in a transient process.
With reference to the second aspect, the negative feedback loop further includes an integrating loop K/s, where K is a customized control parameter and s is a complex parameter;
the negative feedback is specifically used for: offset the angular frequency by an amount delta omega pll After passing through the integrating loop of the negative feedback loop, an additional virtual voltage DeltaU is generated tq And virtual voltage DeltaU tq And feeding back to the input end of the phase-locked loop.
With reference to the second aspect, further, in the transient stability control module, a reshaped phase-locked loop synchronization characteristic equation is as follows:
wherein J is v In order for the coefficient of rotational inertia to be the same,to use adaptive control of post virtual prime mover torque, T v To use the self-adaptive control to post-virtual electromagnetic torque, D v For damping coefficient, k p Is the proportional control coefficient of the phase-locked loop, L g For the grid-side inductance value, < >>Is d-axis current command value, k i For integrating control coefficients, ω, of the phase-locked loop pll For outputting angular frequency, omega for phase-locked loop g For the angular frequency of the power grid,for q-axis current command value, R g Is the line resistance, U g The delta is the angle difference between the grid voltage and the output voltage of the inverter, and K is the self-adaptive control parameter.
In a third aspect, the present invention provides a computer readable storage medium, on which a computer program is stored, which when being executed by a processor, implements the adaptive transient stability control method of a wind power grid-connected system according to the first aspect.
In a fourth aspect, the present invention provides an apparatus comprising:
a memory for storing instructions;
and the processor is used for executing the instructions to enable the equipment to execute the operation of realizing the adaptive transient stability control method of the wind power grid-connected system according to the first aspect.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a wind power grid-connected system self-adaptive transient stability control method, a device, a storage medium and equipment based on angular frequency offset, wherein a negative feedback loop is added in a phase-locked loop, the angular frequency offset is used as a negative feedback quantity to be introduced into the input end of the phase-locked loop, the wind power grid-connected system is further self-adaptively adjusted according to the angular frequency offset, the dynamic characteristics of the phase-locked loop are remodeled, and the inverter is kept synchronous with a power grid in the transient process under the condition that equipment hardware is not increased, so that the safe and stable operation of the power system is ensured.
Drawings
FIG. 1 is a schematic diagram of a direct-drive wind power grid-connected system;
FIG. 2 is a schematic diagram of a wind power grid-connected system with a negative feedback loop in an embodiment of the invention;
FIG. 3 is a schematic diagram of a step flow of a wind power grid-connected system adaptive transient stability control method based on angular frequency offset;
FIG. 4 is a schematic diagram of spatial position relationship of output power angles of a PLL in an embodiment of the present invention;
FIG. 5 is a phase trajectory diagram of a wind power grid-connected system employing adaptive control in an embodiment of the present invention;
fig. 6 is a schematic diagram of a parameter design flow of the adaptive control parameter K according to an embodiment of the present invention.
Detailed Description
It should be noted that: the existing direct-drive wind power grid-connected system is shown in figure 1, and mainly comprises a permanent magnet synchronous generator, a machine side converter, a grid-connected inverter and a power grid, wherein a phase-locked loop can be arranged between the grid-connected inverter of the wind power grid-connected system and the power grid, and is used for controlling the synchronization of the system through the phase-locked loop, but when the power grid has a short-circuit fault, the dynamic characteristic of the phase-locked loop is destroyed, and the transient synchronous stability of the wind power grid-connected system in the fault period cannot be maintained, so that a negative feedback loop is added between the input end and the output end of the phase-locked loop, the angular frequency offset of the system is introduced into the input end of the phase-locked loop through the negative feedback loop, the dynamic characteristic of the phase-locked loop is remodelled, and the wind with self-adaptive transient stable control capability is obtainedAn electrical grid-tie system as shown in fig. 2. In FIGS. 1 and 2, U dc For inverter input voltage, L f Filtering inductance for inverter, C f For the filter capacitance of the inverter, u a 、u b 、u c Respectively a phase voltage, b phase voltage and c phase voltage, R g Is the line resistance, L g Is the inductance of the power grid side, U q For phase-locked loop input voltage, k p Is the proportional control coefficient of the phase-locked loop, k i Is the integral control coefficient of the phase-locked loop, s is a complex parameter, and delta omega pll As an amount of angular frequency offset, g for the angular frequency, θ of the network pll For phase-locked loop output phase angle, K is adaptive control parameter, deltaU tq Is Deltaomega pll The virtual voltage generated after integrating K/s.
The following detailed description of the present invention is made with reference to the accompanying drawings and specific embodiments, and it is to be understood that the specific features of the embodiments and the embodiments of the present invention are detailed description of the technical solutions of the present invention, and not limited to the technical solutions of the present invention, and that the embodiments and the technical features of the embodiments of the present invention may be combined with each other without conflict.
Example 1
The embodiment introduces a wind power grid-connected system adaptive transient stability control method based on angular frequency offset, and performs adaptive transient stability control based on the system structure in fig. 2, as shown in fig. 3, and specifically includes:
and step A, obtaining an angular frequency offset according to the output angular frequency of the phase-locked loop and the angular frequency of the power grid in the wind power grid-connected system.
And B, obtaining virtual voltage through a negative feedback loop preset in the phase-locked loop according to the angular frequency offset, and feeding back the virtual voltage to the input end of the phase-locked loop.
And C, adaptively controlling the wind power grid-connected system based on the virtual voltage, and remolding a phase-locked loop synchronization characteristic equation to enable an inverter in the wind power grid-connected system to keep synchronization with a power grid in a transient process.
In dq coordinates, the characteristic equation of the phase-locked loop is:
wherein U is td Output voltage U of grid-connected inverter in wind power grid-connected system t In the d-axis component of the phase-locked loop coordinate system, U tq Is U (U) t In the q-axis component of the phase-locked loop coordinate system, delta is U t And U g Angle difference, called work angle, I d For outputting d-axis component, omega of current in phase-locked loop coordinate system pll For phase-locked loop output angular frequency, I q The q-axis component of the phase-locked loop coordinate system is used for outputting current.
In wind power grid-connected control, the bandwidth of the current inner loop is far higher than that of the phase-locked loop, and the dynamic response of the current inner loop is far faster than that of the phase-locked loop, so that the influence of the current inner loop on the phase-locked loop can be ignored, and the method comprises the following steps:
wherein,,for d-axis current command value,/->Is the q-axis current command value.
In order to accurately describe the synchronization characteristics of the inverter and the power grid, the invention defines the power angle delta as the phase-locked loop output phase angle and the power grid phase angle difference. The expression of the power angle delta according to the spatial position relation of the output power angle of the phase-locked loop in fig. 4 is:
δ＝∫(ω pll -ω g )dt (3)
based on formulas (1) - (3), a phase-locked loop type inverter synchronization equation under the condition that no negative feedback loop is added is obtained, and the specific expression is as follows:
as can be seen from the formula (4), the phase-locked loop type inverter synchronization equation has similarity with the synchronous generator phase-locked loop type inverter synchronization equation. Phase locked loop synchronous inverters may exhibit oscillation behavior similar to rotor wobble when they fail, out of synchronization with the grid.
In order to solve the problems, the invention adds a negative feedback loop in the phase-locked loop, wherein the negative feedback loop comprises an integral loop K/s, and the angular frequency offset can be introduced into the input end of the phase-locked loop as the negative feedback quantity through the negative feedback loop.
The basic idea of the method of the invention is that: under normal conditions, the frequency and the phase of the power grid should be kept unchanged, and at this time, the output angular frequency of the phase-locked loop and the angular frequency of the power grid are kept synchronous, and no deviation exists between the output angular frequency of the phase-locked loop and the angular frequency of the power grid. If the power grid is greatly disturbed and influenced by short-circuit fault, the phase-locked loop outputs angular frequency omega pll Angular frequency omega to the grid g An offset delta omega is generated between the two pll ，Δω pll ＝ω pll -ω g Therefore, errors are generated between the output phase angle of the inverter and the phase angle of the power grid, and the transient instability phenomenon of the wind power grid-connected system is caused. To counteract this phase error, the method of the present invention shifts the angular frequency by an amount Δω pll After passing through the integrating loop, an additional virtual voltage DeltaU is generated tq And negatively feed back the same to the phase-locked loop input loop, and add the virtual voltage DeltaU tq The output phase angle of the inverter and the phase angle error of the power grid can be self-adaptively counteracted according to the angular frequency deviation. The control strategy of the method can adaptively adjust the balance of the virtual moment of the virtual synchronous generator, remodel the dynamic characteristics of the phase-locked loop, and ensure that the inverter is kept synchronous with the power grid in the transient process.
In step C, the above adaptive transient control strategy is adopted, and the phase-locked loop synchronization characteristic equation after remodeling is as follows:
wherein,,and T v The self-adaptive control is adopted to control the virtual prime motor torque and the virtual electromagnetic torque, and the balance of the two is the key for keeping the transient synchronous stability; j (J) v And D v The moment of inertia coefficient and the damping coefficient, respectively.
Comparing equation (4) with equation (5), it can be known that the phase-locked loop synchronization characteristic is changed under the action of the adaptive transient control strategy of the present invention. The damping coefficient of the wind power grid-connected system is obviously increased, and the wind power grid-connected system has stronger anti-interference performance and disturbance inhibition capability, so that the reliability and stability of the wind power grid-connected system are improved. More importantly, the introduction of adaptive transient control, virtual electromagnetic torque T v According to the self-adaptive adjustment of the angular frequency offset, the system has the capability of automatically searching a balance working point after suffering from large interference such as load change, power grid fault and the like, so that the synchronous characteristic with the power grid is maintained.
In the embodiment of the invention, the effect of the method of the invention is further analyzed by combining the following two cases:
1) Virtual prime mover torqueMoment surplus exists in wind power grid-connected system, so that omega PLL >ω g At this time, the angular frequency is shifted by Δω pll ＝ω pll -ω g Is positive, T v Will increase with increasing angular frequency offset. Due to the action of the integral controller in the negative feedback loop, the virtual electromagnetic torque T is as long as angular frequency deviation exists v Will increase until the virtual prime mover torque +.>And virtual electromagnetic torque T v The equilibrium is reached, at which point the system has a new equilibrium point and the inverter remains synchronized with the grid.
2) Virtual prime mover torqueThe system has moment deficiency such that omega PLL <ω g At this time, the angular frequency is shifted by Δω pll ＝ω pll -ω g Negative number, T v Will decrease as the angular frequency offset increases. Due to the action of the integral controller in the negative feedback loop, the virtual electromagnetic torque T is as long as angular frequency deviation exists v Will decrease until the virtual prime mover torque +.>And virtual electromagnetic torque T v The equilibrium is reached, at which point the system has a new equilibrium point and the inverter remains synchronized with the grid.
FIG. 5 is a phase trajectory diagram of a wind grid system employing adaptive control. It can be seen from the figure that the system can be stabilized under the action of different control parameters. When choosing the smaller control parameter (k=0.05), the power angle will cross the maximum allowable overshoot and after several periodic oscillations reach the equilibrium point b to resynchronize with the grid, which is called non-asymptotic stabilization; when a larger control parameter is chosen (k=0.1), the power angle does not go beyond the maximum allowed value, but converges directly to the equilibrium point a, which is called progressive stabilization. Non-asymptotic stabilization produces a greater power angle overshoot than asymptotic stabilization and requires more time to reach the equilibrium point.
In order to obtain better dynamic performance, the invention needs to design and optimize the self-adaptive control parameter K in the negative feedback loop so as to realize progressive stability. In practical operation, the parameter K should not be too small and too large, because too large parameter K will increase the oscillation time, so the method of the invention needs to find the critical value of the parameter K to make the system reach gradual stability exactly.
In the embodiment of the present invention, the optimal design of the adaptive control parameter K is found by an iterative algorithm as shown in fig. 6:
initializing the adaptive control parameter K to a small value, e.g. 0.01, K 0 . Solving by utilizing a second-order synchronous equation of the phase-locked loop through MATLAB command 'ode 45' to obtain a power angle delta under different time,determining whether the power angle delta exceeds a set maximum overshoot delta max . If delta > delta max Then entering the next iteration, adding 0.01 to the self-adaptive control parameter in each iteration, and recalculating the real-time power angle; if delta is less than or equal to delta max The iteration is terminated, and K is the critical value, namely the optimal value K in the method cr 。
Example 2:
based on the same inventive concept as that of embodiment 1, this embodiment introduces a wind power grid-connected system adaptive transient stability control device based on angular frequency offset, which includes a data acquisition module, a negative feedback module and a transient stability control module.
The data acquisition module is mainly used for obtaining the angular frequency offset according to the output angular frequency of the phase-locked loop and the angular frequency of the power grid in the wind power grid-connected system.
The negative feedback module is mainly used for obtaining virtual voltage through a negative feedback loop preset in the phase-locked loop according to the angular frequency offset, and feeding the virtual voltage back to the input end of the phase-locked loop. The negative feedback loop comprises an integral loop K/s, wherein K is a self-defined control parameter, and s is a complex parameter. Angular frequency offset Δω pll An additional virtual voltage DeltaU can be generated after the integration loop of the negative feedback loop tq Additional virtual voltage DeltaU tq The output phase angle of the inverter and the phase angle error of the power grid can be self-adaptively counteracted according to the angular frequency deviation.
The transient stability control module is mainly used for adaptively controlling the wind power grid-connected system based on the virtual voltage, and remolding a phase-locked loop synchronization characteristic equation to enable an inverter in the wind power grid-connected system to keep synchronization with a power grid in a transient process.
In the transient stability control module, the remodeled phase-locked loop synchronization characteristic equation is as follows:
wherein J is v In order for the coefficient of rotational inertia to be the same,to use adaptive control of post virtual prime mover torque, T v To use the self-adaptive control to post-virtual electromagnetic torque, D v For damping coefficient, k p Is the proportional control coefficient of the phase-locked loop, L g For the grid-side inductance value, < >>Is d-axis current command value, k i For integrating control coefficients, ω, of the phase-locked loop pll For outputting angular frequency, omega for phase-locked loop g For the angular frequency of the power grid,for q-axis current command value, R g Is the line resistance, U g The delta is the angle difference between the grid voltage and the output voltage of the inverter, and K is the self-adaptive control parameter.
Example 3:
based on the same inventive concept as embodiment 1, this embodiment introduces a computer-readable storage medium on which a computer program is stored, which when executed by a processor, implements the adaptive transient stability control method of the wind power grid-connected system in embodiment 1.
Example 4:
the present embodiment introduces an apparatus based on the same inventive concept as embodiment 1, including: a memory for storing instructions; and the processor is used for executing the instructions to enable the equipment to execute the operation of realizing the adaptive transient stability control method of the wind power grid-connected system in the embodiment 1.
In summary, the invention solves the problems that the existing control strategy is limited by the capacity of the converter and the transient stability of the wind power grid-connected system is difficult to solve during the fault period, provides a new control strategy based on the negative feedback loop, utilizes the angular frequency offset as the negative feedback quantity to be introduced into the input end of the phase-locked loop, reshapes the dynamic characteristic of the phase-locked loop, and realizes the synchronization of the inverter and the power grid in the wind power grid-connected system when the power grid breaks down.
The invention has strong self-adaptive capacity, is not limited by factors such as disturbance type, system parameters, converter capacity and the like, and does not need complicated parameter adjustment. The method is not only suitable for fan current source type inverters, but also can be popularized and applied in voltage source type inverters and multi-machine parallel systems.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention 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 invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations 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.
The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the claims, which are all within the protection of the present invention.

Claims (10)

1. The self-adaptive transient stability control method of the wind power grid-connected system based on angular frequency deviation is characterized by comprising the following steps of:
obtaining an angular frequency offset according to the output angular frequency of a phase-locked loop and the angular frequency of a power grid in the wind power grid-connected system;
according to the angular frequency offset, virtual voltage is obtained through a negative feedback loop preset in the phase-locked loop, and the virtual voltage is fed back to the input end of the phase-locked loop;
based on the virtual voltage self-adaptive control wind power grid-connected system, a phase-locked loop synchronization characteristic equation is remodeled, so that an inverter in the wind power grid-connected system is kept synchronous with a power grid in a transient process.
2. The adaptive transient stability control method of a wind power grid-connected system based on angular frequency offset according to claim 1, wherein the negative feedback loop comprises an integral loop K/s, wherein K is a self-defined control parameter, and s is a complex parameter.
3. The adaptive transient stability control method for a wind power grid-connected system based on angular frequency offset according to claim 2, wherein the angular frequency offset Δω is calculated by pll Integration through negative feedback loopAfter the loop, an additional virtual voltage DeltaU is generated tq And virtual voltage DeltaU tq Is fed back to the input end of the phase-locked loop through the virtual voltage delta U tq And (3) adaptively counteracting errors of an output phase angle of an inverter and a phase angle of a power grid in the wind power grid-connected system.
4. The adaptive transient stability control method of a wind power grid-connected system based on angular frequency offset according to claim 1, wherein the remodeled phase-locked loop synchronization characteristic equation is as follows:
wherein J is v In order for the coefficient of rotational inertia to be the same,to use adaptive control of post virtual prime mover torque, T v To use the self-adaptive control to post-virtual electromagnetic torque, D v For damping coefficient, k p Is the proportional control coefficient of the phase-locked loop, L g For the grid-side inductance value, < >>Is d-axis current command value, k i For integrating control coefficients, ω, of the phase-locked loop pll For outputting angular frequency, omega for phase-locked loop g For grid angular frequency>For q-axis current command value, R g Is the line resistance, U g The delta is the angle difference between the grid voltage and the output voltage of the inverter, and K is the self-adaptive control parameter.
5. The adaptive transient stability control method of a wind power grid-connected system based on angular frequency offset according to claim 2, wherein obtaining the optimal value of the adaptive control parameter K by an iterative algorithm comprises:
initializing an adaptive control parameter K; solving by utilizing a second-order synchronous equation of a phase-locked loop through MATLAB command 'ode 45' to obtain a real-time power angle delta under the current self-adaptive control parameter; judging whether the power angle delta exceeds the set maximum overshoot delta max The method comprises the steps of carrying out a first treatment on the surface of the If delta > delta max Adding 0.01 to the self-adaptive control parameter, and recalculating the real-time power angle according to the updated self-adaptive control parameter K until delta is less than or equal to delta max The method comprises the steps of carrying out a first treatment on the surface of the If delta is less than or equal to delta max The iteration is terminated, and the optimal value K of the adaptive control parameter K is output cr 。
6. An adaptive transient stability control device of a wind power grid-connected system based on angular frequency deviation is characterized by comprising:
the data acquisition module is used for obtaining an angular frequency offset according to the output angular frequency of the phase-locked loop and the angular frequency of the power grid in the wind power grid-connected system;
the negative feedback module is used for obtaining virtual voltage through a negative feedback loop preset in the phase-locked loop according to the angular frequency offset and feeding back the virtual voltage to the input end of the phase-locked loop;
the transient stability control module is used for adaptively controlling the wind power grid-connected system based on the virtual voltage, and remolding a phase-locked loop synchronization characteristic equation to enable an inverter in the wind power grid-connected system to keep synchronization with a power grid in a transient process.
7. The adaptive transient stability control device of a wind power grid-connected system based on angular frequency offset according to claim 6, wherein the negative feedback loop comprises an integral loop K/s, wherein K is a self-defined control parameter, and s is a complex parameter;
the negative feedback module is specifically configured to: offset the angular frequency by an amount delta omega pll After passing through the integrating loop of the negative feedback loop, an additional virtual voltage DeltaU is generated tq And virtual voltage DeltaU tq And feeding back to the input end of the phase-locked loop.
8. The adaptive transient stability control device of a wind power grid-connected system based on angular frequency offset according to claim 6, wherein in the transient stability control module, a remodeled phase-locked loop synchronization characteristic equation is as follows:
wherein J is v In order for the coefficient of rotational inertia to be the same,to use adaptive control of post virtual prime mover torque, T v To use the self-adaptive control to post-virtual electromagnetic torque, D v For damping coefficient, k p Is the proportional control coefficient of the phase-locked loop, L g For the grid-side inductance value, < >>Is d-axis current command value, k i For integrating control coefficients, ω, of the phase-locked loop pll For outputting angular frequency, omega for phase-locked loop g For grid angular frequency>For q-axis current command value, R g Is the line resistance, U g The delta is the angle difference between the grid voltage and the output voltage of the inverter, and K is the self-adaptive control parameter.
9. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the method for adaptive transient stability control of a wind power grid connection system according to any one of claims 1-7.
10. An apparatus, comprising:
a memory for storing instructions;
a processor for executing the instructions to cause the apparatus to perform operations to implement the wind power grid-connected system adaptive transient stability control method of any of claims 1-7.
CN202310686464.1A 2023-06-09 2023-06-09 Wind power grid-connected system self-adaptive transient stability control method and device based on angular frequency offset, storage medium and equipment Pending CN116613819A (en)

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