CN113300402B - Self-adaptive virtual impedance control method and system for LCC converter station - Google Patents
Self-adaptive virtual impedance control method and system for LCC converter station Download PDFInfo
- Publication number
- CN113300402B CN113300402B CN202110580711.0A CN202110580711A CN113300402B CN 113300402 B CN113300402 B CN 113300402B CN 202110580711 A CN202110580711 A CN 202110580711A CN 113300402 B CN113300402 B CN 113300402B
- Authority
- CN
- China
- Prior art keywords
- lcc
- impedance
- converter station
- virtual impedance
- direct current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 32
- 230000005540 biological transmission Effects 0.000 claims abstract description 50
- 238000001914 filtration Methods 0.000 claims abstract description 38
- 230000003044 adaptive effect Effects 0.000 claims description 39
- 230000000694 effects Effects 0.000 claims description 24
- 238000005259 measurement Methods 0.000 claims description 13
- 238000012887 quadratic function Methods 0.000 claims description 8
- 238000004364 calculation method Methods 0.000 claims description 7
- 238000010304 firing Methods 0.000 claims 2
- 238000010276 construction Methods 0.000 claims 1
- 230000006870 function Effects 0.000 description 50
- 238000010586 diagram Methods 0.000 description 16
- 238000013016 damping Methods 0.000 description 14
- 238000003860 storage Methods 0.000 description 14
- 238000004590 computer program Methods 0.000 description 9
- 238000012545 processing Methods 0.000 description 5
- 238000011160 research Methods 0.000 description 5
- 238000004088 simulation Methods 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 101100499229 Mus musculus Dhrsx gene Proteins 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004422 calculation algorithm Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000368 destabilizing effect Effects 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- HOWHQWFXSLOJEF-MGZLOUMQSA-N systemin Chemical compound NCCCC[C@H](N)C(=O)N[C@@H](CCSC)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](CC(O)=O)C(=O)OC(=O)[C@@H]1CCCN1C(=O)[C@H]1N(C(=O)[C@H](CC(O)=O)NC(=O)[C@H](CCCN=C(N)N)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CO)NC(=O)[C@H]2N(CCC2)C(=O)[C@H]2N(CCC2)C(=O)[C@H](CCCCN)NC(=O)[C@H](CO)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@@H](NC(=O)[C@H](C)N)C(C)C)CCC1 HOWHQWFXSLOJEF-MGZLOUMQSA-N 0.000 description 1
- 108010050014 systemin Proteins 0.000 description 1
Images
Classifications
-
- 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
- H02J3/01—Arrangements for reducing harmonics or ripples
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for AC mains or AC distribution networks
- H02J3/36—Arrangements for transfer of electric power between AC networks via a high-tension DC link
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
-
- 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
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
The invention discloses a self-adaptive virtual impedance control method and a self-adaptive virtual impedance control system for an LCC converter station.A high-pass filter is used as a link for filtering a direct current component of self-adaptive virtual impedance, and the link for filtering the direct current component is obtained according to cut-off frequency; determining a direct current reference value of an LCC converter station in the LCC-VSC hybrid direct current transmission system; determining boundary conditions of a control system of the LCC converter station and the type of an impedance function of the used self-adaptive virtual impedance; determining an impedance function of the self-adaptive virtual impedance according to the boundary condition and the impedance function type by using a direct current reference value of the LCC converter station; determining the feedforward gain of the self-adaptive virtual impedance control according to the impedance function and the link of filtering the direct current component; and the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct-current transmission system is realized by controlling the feedforward gain. The invention effectively improves the small signal stability of the system.
Description
Technical Field
The invention belongs to the technical field of direct current transmission, and particularly relates to a self-adaptive virtual impedance control method and system for an LCC converter station.
Background
The direct-current power transmission technology based on the power electronic device can realize stable new energy grid connection, has research value in the direction of constructing a direct-current power grid, and can realize large-scale new energy grid connection and large-capacity long-distance power transmission. The traditional LCC-HVDC (Line Committed Converter High Voltage Direct Current) technology has the advantage of large transmission capacity, but has the problem of phase commutation failure and can not supply power to a passive network; the VSC-HVDC (Voltage Source Converter High Voltage Direct Current) technology based on the full-control device can decouple and control active and reactive power, can supply power to a weak alternating Current power grid, and does not have the problem of commutation failure. In order to combine the respective advantages of the LCC and the VSC, the research community proposes a concept of a hybrid direct-current transmission system, which has a wider application prospect. With the rise of voltage level and the increase of transmission capacity of the dc engineering put into operation nowadays, the stability of dc transmission at a steady-state operating point is gradually paid attention by scholars. Firstly, the stable characteristic of the direct current system near a stable working point shows the anti-interference capability of the system and determines whether the direct current system can stably run or not; secondly, through impedance analysis, reference basis can be provided for design and optimization improvement of equipment selection and control systems.
The normal operation of the dc transmission system is mainly dependent on the control system of the converter station. The control of the actual direct current transmission system engineering usually adopts a master-slave control strategy, namely one converter station adopts constant direct current voltage control, and the other converter stations adopt constant power control. When the constant power control station operates in an inversion state, the impedance action of the converter station on the system can be equivalent to negative impedance, and the negative impedance characteristic is stronger when the power is transmitted. If the remainder of the dc system does not provide sufficient positive damping characteristics, the system will likely enter a glitch destabilizing state. Therefore, the stability of the direct current side of the system can be improved by increasing the equivalent resistance of the direct current system. The method for increasing the equivalent resistance comprises the steps of (1) adding actual impedance, and (2) realizing positive damping effect through a control algorithm, namely adding virtual impedance control. Because the addition of the actual impedance can cause the increase of system loss, and the method has no practicability in engineering, the current common method is to add a virtual impedance control link. Existing research on virtual impedance control is mostly directed to control systems of the VSC converter station, and research on virtual impedance control of the LCC converter station is still vacant.
The constant direct current control of a common direct current system is shown in fig. 1, and an actual direct current is subjected to a difference with a current instruction value after passing through a measurement link, then passes through a PI controller, is subjected to a difference with PI, and is output to a trigger control system. The traditional constant direct current control adopted at the LCC side has strict requirements on PI parameters, and the small interference instability of the system can be caused by slightly larger or smaller values, so that certain difficulties are caused in simulation research and subsequent analysis of a direct current system.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a method and a system for controlling an adaptive virtual impedance of an LCC converter station, which overcome the shortcomings in the prior art, and adopt a design of a variable impedance coefficient to ensure that the system can quickly respond to a small signal interference condition and quickly return to a stable state, thereby effectively improving the stability of a dc transmission system including the LCC converter station.
The invention adopts the following technical scheme:
a self-adaptive virtual impedance control method for an LCC converter station comprises the following steps:
s1, determining cutoff frequency omega of used adaptive virtual impedance direct-current component filtering link according to alternating-current side power frequency angular frequency of LCC converter station control system in LCC-VSC hybrid direct-current transmission system c A high-pass filter is used as a link for filtering out direct-current components of the self-adaptive virtual impedance according to the cut-off frequency omega c Obtaining a link of filtering direct current components;
s2, determining a direct current reference value of an LCC converter station control system in the LCC-VSC hybrid direct current transmission system;
s3, when the LCC converter station control system operates in a steady state, the virtual impedance effect is maximum; when the LCC converter station control system is in a direct current transmission system starting state, the virtual impedance effect is minimum; when the LCC converter station control system operates in a steady state, the derivative of the virtual impedance relative to the direct-current side current measurement value of the LCC converter station control system is 0, and the impedance function type of the self-adaptive virtual impedance used in the LCC converter station control system is determined;
s4, determining an impedance function of the self-adaptive virtual impedance according to the boundary condition, the impedance function type and the direct current reference value of the LCC converter station obtained in the step S2 obtained in the step S3;
s5, determining the feedforward gain of the self-adaptive virtual impedance control according to the impedance function obtained in the step S4 and the filtered direct-current component link obtained in the step S1; and the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct current transmission system is realized by controlling the feedforward gain.
Specifically, in step S1, the frequency domain of the link for filtering the dc component is
s is the frequency domain variable.
Further, a cut-off frequency ω c Less than the power frequency angular frequency.
Specifically, in step S2, the dc reference value i dcref The calculation is as follows:
wherein, P LCCref For rated power, U, of LCC converter station dcref The voltage is rated for the dc side of the LCC converter station.
Specifically, in step S3, the impedance function type of the adaptive virtual impedance is a quadratic function type, and the boundary condition of the quadratic function type structure is specifically: r (i) dc ＝0)＝0，R(i dc ＝i dcref ) =1 and R' (i) dc ＝i dcref )＝0，i dcref Is a DC current reference value, i dc For direct current, R is the adaptive virtual impedance with respect to direct current i dc The impedance function of (a).
Specifically, in step S4, DC current i is applied dc Is equal to the reference value i of the direct current dcref Adaptive virtual impedance function R (i) dc ) The control degenerates into virtual impedance control of a constant impedance coefficient; adaptive virtual impedance function R (i) at offset steady state dc ) Control degenerates to conventional constant dc current control.
Further, an adaptive virtual impedance function R (i) is determined by constructing an impedance function R term using a quadratic function dc ) Comprises the following steps:
wherein i dcref Is a DC current reference value i dc Is a direct current.
Specifically, in step S5, the product of the adaptive virtual impedance function and the filtered dc link is used as a feed-forward gain of the dc current measurement value, the feed-forward gain is fed back to the dc current control link of the LCC converter station control system, a trigger angle instruction value is obtained through the PI controller, and the trigger angle instruction value is output to the thyristors of each bridge arm to realize turn-on.
Another technical solution of the present invention is a system for controlling an adaptive virtual impedance of an LCC converter station, including:
the frequency module is used for determining the cutoff frequency omega of the used adaptive virtual impedance direct-current component filtering link according to the alternating-current side power frequency angular frequency of the LCC converter station control system in the LCC-VSC hybrid direct-current transmission system c Using a high-pass filter as a link for filtering the direct-current component of the self-adaptive virtual impedance according to the cut-off frequency omega c Obtaining a link for filtering direct current components;
the calculation module is used for determining a direct current reference value of an LCC converter station in the LCC-VSC hybrid direct current transmission system;
the boundary module is used for maximizing the virtual impedance effect when the LCC converter station control system operates in a steady state; when the LCC converter station control system is in a direct current transmission system starting state, the virtual impedance effect is minimum; when the LCC converter station control system operates in a steady state, the derivative of the virtual impedance relative to the LCC direct current side current measurement value is 0 and serves as a boundary condition, and the impedance function type of the self-adaptive virtual impedance used in the LCC converter station control system is determined;
the impedance module is used for determining an impedance function of the self-adaptive virtual impedance according to the boundary condition obtained by the boundary module, the impedance function type and the direct current reference value of the LCC converter station obtained by the boundary module;
the control module determines the feedforward gain of the self-adaptive virtual impedance control according to the impedance function obtained by the impedance module and the filtered direct-current component link obtained by the frequency module; and the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct-current transmission system is realized by controlling the feedforward gain.
Compared with the prior art, the invention has at least the following beneficial effects:
after the LCC converter station adopts the self-adaptive virtual impedance control claimed by the invention, because the virtual impedance link can increase the positive damping characteristic of the equivalent impedance at the direct current side of the LCC system, the system can quickly respond and enter a new stable state after interference occurs, and the transient process is shortened. The method can be obtained from the knowledge of an impedance analysis method, and the stability of the direct current system depends on the equivalent direct current side impedance of the input end and the output end; after the virtual impedance control claimed by the invention is adopted, the impedance positive characteristic of the equivalent direct current side of the LCC system is increased, the stability of the system is improved, and therefore, the selection of the control parameters of the LCC converter station is looser.
Further, the direct current part in the feedback quantity is filtered by using the straight filtering loop section as a product term of the self-adaptive virtual impedance, so that the input of the self-adaptive impedance control is the alternating current part in the feedback quantity.
Furthermore, in order to avoid the influence of a steady-state component in the direct current measurement value on control, so that a steady-state operation point of the system is changed, a filter for filtering the direct current component is designed in the feedback path, and a high-pass filter is adopted, so that the influence on control of the electric quantity on the power frequency side is avoided, and the cutoff frequency is selected to be smaller than the power frequency angular frequency.
Further, a direct current reference value i is obtained through calculation of rated power of the LCC converter station and rated voltage of a direct current side dcref And selecting the adaptive impedance control parameters corresponding to the steady-state working condition of the system.
Furthermore, the impedance function R term is constructed by using a quadratic function, so that three boundary conditions considered in the step S2 can be met, the function form is simple, and the control system is convenient to realize.
Further, a direct current i is added in the control loop dc The gain is sR (i) dc )/(s+ω c )，R(Δi dc ) Is as a function of Δ i dc Varying adaptive product term, s/(s + ω) c ) For filtering out DC component, preventing DC component in feedback quantity from changing steady state operation parameter, determining and considering R (i) dc = 0) =0; considering that the virtual impedance action of the feedback quantity becomes stronger in the process that the system enters the steady state, the damping action is stronger under the condition of being closer to the steady state, and the feedback quantity is degraded into the virtual impedance control with constant damping coefficient in the steady state, determining R (i) dc ＝i dcref ) =1; r' (i) is determined in consideration of the fact that the impedance coefficient can smoothly transit at the steady state dc ＝i dcref )＝0。
Further, in i dc ＝i dcref Namely when the system runs in a rated state, the positive damping effect of the controller reaches the maximum, the virtual impedance of the system is ensured to play a role in a steady state, and the small signal stability of a steady-state running point is increased; when the system is in an offset steady state, the self-adaptive virtual impedance control is degraded to the constant direct current control, so that the system can respond quickly when the working condition is changed, and the control effect of the system is ensured.
Further, the self-adaptive virtual impedance control of the LCC side is realized according to the piecewise function of the step S5, the stability of the LCC is ensured through the virtual impedance control under the condition of a system steady state, and the system response is ensured to be rapid under the condition of a system transient state.
Further, according to the DC reference valuei dcref With an adaptive virtual impedance function R (i) dc ) And the selected virtual impedance is controlled, and the damping effect can be adjusted according to the current working condition.
In conclusion, the damping effect can be adjusted according to the direct current measured value of the LCC converter station, and the small signal stability of the system is effectively improved.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a conventional constant DC current control diagram for an LCC converter station;
FIG. 2 is a diagram of an adaptive virtual impedance control diagram for an LCC converter station according to the present invention;
FIG. 3 is a diagram illustrating the relationship between the impedance coefficient of the virtual impedance and the DC current;
FIG. 4 is a voltage-current variation diagram in a steady state of the system, in which (a) is a system DC voltage variation and (b) is a system DC current variation;
FIG. 5 is a simulated waveform diagram of the absorbed power of the boosted constant power station, wherein (a) is the system DC voltage variation and (b) is the system DC current variation;
fig. 6 is a small-signal equivalent circuit diagram of the hybrid multi-terminal direct-current power transmission system.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.
Various structural schematics according to the disclosed embodiments of the invention are shown in the drawings. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.
The virtual resistance control is to add a feedback quantity to simulate the actual impedance on the basis of the original constant DC current control loop, generally set a deviation quantity of current or power to be multiplied by a resistance, and then give the product to the constant DC current control loop as the deviation quantity. The invention provides a self-adaptive virtual impedance control method for an LCC converter station, which is characterized in that a feedback quantity based on direct current is added in the traditional constant direct current control of the LCC converter station to simulate the actual impedance, and the system is realized to show the positive damping characteristic to a direct current port through a control system, so that the stability of the direct current side of the system is improved.
Referring to fig. 2, a method for controlling adaptive virtual impedance of an LCC converter station according to the present invention includes the following steps:
s1, determining the cutoff of a direct-current component filtering link of a used self-adaptive virtual impedance according to the alternating-current side power frequency angular frequency of an LCC converter station control system in an LCC-VSC hybrid direct-current transmission systemStop frequency omega c Using a high-pass filter as a link for filtering the direct-current component of the self-adaptive virtual impedance according to the cut-off frequency omega c Obtaining a link for filtering direct current components;
the frequency domain expression of the link for filtering the direct current component is
s is the frequency domain variable.
Cut-off frequency omega c The angular frequency is less than the power frequency, preferably 50rad/s.
S2, determining a direct current reference value of an LCC converter station in the LCC-VSC hybrid direct current transmission system;
direct current reference value i for determining an impedance function of an adaptive virtual impedance dcref (ii) a Obtaining rated power P of LCC converter station according to steady state working condition of hybrid direct current transmission system LCCref With the rated voltage U of the DC side dcref To obtain i dcref Comprises the following steps:
s3, when the LCC converter station control system operates in a steady state, the virtual impedance effect is maximum; when the LCC converter station control system is in a direct current transmission system starting state, the virtual impedance effect is minimum; when the LCC converter station control system operates in a steady state, the derivative of the virtual impedance relative to the LCC direct current side current measurement value is 0 and serves as a boundary condition, and the impedance function type of the self-adaptive virtual impedance used in the LCC converter station control system is determined;
adding a term based on DC current i in the control loop dc The gain is sR (i) dc )/(s+ω c )，R(Δi dc ) Is as a function of Δ i dc Varying adaptive product term, s/(s + ω) c ) For filtering out DC component, preventing DC component in feedback quantity from changing steady state operation parameter, determining and considering R (i) dc = 0) =0; virtual impedance function change in the process that the direct current side direct current of the LCC converter station approaches the direct current reference value when the hybrid direct current transmission system enters a steady state and the feedback quantity is consideredStrong, and the damping effect is stronger the closer to the steady state condition, and degraded to the virtual impedance control of the constant damping coefficient at the steady state, R (i) is determined dc ＝i dcre ) f =1; r' (i) is determined in consideration of the fact that the impedance coefficient can smoothly transit at the steady state dc ＝i dcre ) f ＝0；
S4, determining an impedance function of the self-adaptive virtual impedance according to the boundary condition, the impedance function type and the direct current reference value of the LCC converter station obtained in the step S2 obtained in the step S3;
referring to FIG. 3, the function type is obtained from the factors of step S2, and the impedance function R term is constructed by using the quadratic function to construct R (i) dc ) Comprises the following steps:
wherein i dcref Is a dc current reference value.
The purpose of constructing the virtual resistance using the function is to construct the virtual resistance at i dc ＝i dcref Namely, in steady state operation, the direct current offset plays a positive damping role, and the adaptive virtual impedance function R (i) at the moment dc ) The control degenerates into virtual impedance control of a constant impedance coefficient; and under the condition of an offset steady state, the controller participates in adjusting the steady state, and does not introduce a high-order current offset term, wherein the self-adaptive virtual impedance function R (i) is adopted dc ) Control degenerates to conventional constant dc current control.
S5, determining the feedforward gain of the self-adaptive virtual impedance control according to the impedance function obtained in the step S4 and the filtered direct-current component link obtained in the step S1; and the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct-current transmission system is realized by controlling the feedforward gain.
The expression R (i) of the adaptive virtual impedance function is obtained from the steps S5 and S1 dc ) And filtering out direct current link
The product of the two is used as the feedback gain of the DC current measurement value and is sent to the original LCC control systemIn the constant direct current control link, a trigger angle instruction value is obtained through the PI controller. For nominal operating state i of the system dc ＝i dcref The positive damping effect provided by the adaptive virtual impedance control is strongest under the working condition of (1).
In the constant direct current control of the LCC converter station, the feedforward gain obtained in the step S6 is added between a measured value output by the direct current side through the sampling link and the direct current reference value obtained in the step S2 to be a differential link, so that the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct current transmission system is realized. In another embodiment of the present invention, an adaptive virtual impedance control system for an LCC converter station is provided, where the system can be used to implement the above adaptive virtual impedance control method for the LCC converter station, and specifically, the adaptive virtual impedance control system for the LCC converter station includes a frequency module, a calculation module, a boundary module, an impedance module, and a control module.
The frequency module determines the cutoff frequency omega of a used adaptive virtual impedance direct-current component filtering link according to the alternating-current side power frequency angular frequency of an LCC converter station control system in the LCC-VSC hybrid direct-current transmission system c Using a high-pass filter as a link for filtering the direct-current component of the self-adaptive virtual impedance according to the cut-off frequency omega c Obtaining a link for filtering direct current components;
the calculation module is used for determining a direct current reference value of an LCC converter station in the LCC-VSC hybrid direct current transmission system;
the boundary module is used for maximizing the virtual impedance effect when the LCC converter station control system operates in a steady state; when the LCC converter station control system is in a direct current transmission system starting state, the virtual impedance effect is minimum; when the LCC converter station control system operates in a steady state, the derivative of the virtual impedance relative to the LCC direct current side current measurement value is 0 and serves as a boundary condition, and the impedance function type of the self-adaptive virtual impedance used in the LCC converter station control system is determined;
the impedance module is used for determining an impedance function of the self-adaptive virtual impedance according to the boundary condition obtained by the boundary module, the impedance function type and the direct current reference value of the LCC converter station obtained by the boundary module;
the control module determines the feedforward gain of the self-adaptive virtual impedance control according to the impedance function obtained by the impedance module and the filtered direct-current component link obtained by the frequency module; and the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct-current transmission system is realized by controlling the feedforward gain.
In yet another embodiment of the present invention, a terminal device is provided that includes a processor and a memory for storing a computer program comprising program instructions, the processor being configured to execute the program instructions stored by the computer storage medium. The Processor may be a Central Processing Unit (CPU), or may be other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable gate array (FPGA) or other Programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc., which is a computing core and a control core of the terminal, and is adapted to implement one or more instructions, and is specifically adapted to load and execute one or more instructions to implement a corresponding method flow or a corresponding function; the processor provided by the embodiment of the invention can be used for the operation of the LCC converter station self-adaptive virtual impedance control method, and comprises the following steps:
determining cutoff frequency omega of used adaptive virtual impedance direct-current component filtering link according to alternating-current side power frequency angular frequency of LCC converter station control system in LCC-VSC hybrid direct-current transmission system c Using a high-pass filter as a link for filtering the direct-current component of the self-adaptive virtual impedance according to the cut-off frequency omega c Obtaining a link for filtering direct current components; determining a direct current reference value of an LCC converter station in the LCC-VSC hybrid direct current transmission system; when the LCC converter station control system operates in a steady state, the virtual impedance effect is maximum; when the LCC converter station control system is in a direct current transmission system starting state, the virtual impedance effect is minimum; when the LCC converter station control system operates in a steady state, the derivative of the virtual impedance relative to the LCC direct current side current measured value is 0 and serves as a boundary condition, and the LCC converter station control system is determinedThe type of impedance function of the adaptive virtual impedance used in (1); determining an impedance function of the self-adaptive virtual impedance according to the boundary condition and the impedance function type by using a direct current reference value of the LCC converter station; determining the feedforward gain of the self-adaptive virtual impedance control according to the impedance function and the link of filtering the direct current component; and the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct-current transmission system is realized by controlling the feedforward gain.
In still another embodiment of the present invention, the present invention further provides a storage medium, specifically a computer-readable storage medium (Memory), which is a Memory device in a terminal device and is used for storing programs and data. It is understood that the computer readable storage medium herein may include a built-in storage medium in the terminal device, and may also include an extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space storing an operating system of the terminal. Also, one or more instructions, which may be one or more computer programs (including program code), are stored in the memory space and are adapted to be loaded and executed by the processor. It should be noted that the computer-readable storage medium may be a high-speed RAM memory, or may be a non-volatile memory (non-volatile memory), such as at least one disk memory.
One or more instructions stored in a computer readable storage medium may be loaded and executed by a processor to implement the corresponding steps of the method for controlling adaptive virtual impedance of an LCC converter station in the above embodiments; one or more instructions in the computer-readable storage medium are loaded by the processor and perform the steps of:
determining cutoff frequency omega of used adaptive virtual impedance direct-current component filtering link according to alternating-current side power frequency angular frequency of LCC converter station control system in LCC-VSC hybrid direct-current transmission system c Using a high-pass filter as a link for filtering the direct-current component of the self-adaptive virtual impedance according to the cut-off frequency omega c Obtaining a link for filtering direct current components; determining direct current of LCC converter station in LCC-VSC hybrid direct current transmission systemA current reference value; when the LCC converter station control system operates in a steady state, the virtual impedance effect is maximum; when the LCC converter station control system is in a direct current transmission system starting state, the virtual impedance effect is minimum; when the LCC converter station control system operates in a steady state, the derivative of the virtual impedance relative to the LCC direct current side current measurement value is 0 and serves as a boundary condition, and the impedance function type of the self-adaptive virtual impedance used in the LCC converter station control system is determined; determining an impedance function of the self-adaptive virtual impedance according to the boundary condition and the impedance function type by using a direct current reference value of the LCC converter station; determining the feedforward gain of the self-adaptive virtual impedance control according to the impedance function and the link of filtering the direct current component; and the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct-current transmission system is realized by controlling the feedforward gain.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The parameter selection of the self-adaptive virtual impedance needs to consider a steady-state direct current reference value i dcref Taking the used direct current transmission system simulation model as an example, the power generated by the LCC converter station in a steady state is 5000MW, and the direct current reference value is 6.25kA when the direct current voltage is 800kV. R (i) thus constructed dc ) Comprises the following steps:
s/(s + omega) for filtering out DC components c ) Omega in (1) c Take 50rad/s.
FIG. 6 shows the equivalent circuit diagram of a small signal, Δ u, of the system s1 And Z du Is an equivalent small interference voltage source and an equivalent direct current side impedance, Z of the VSC-I converter station dp And Δ i s2 Is an equivalent small interference current source and an equivalent direct current side impedance, Z of the VSC-II converter station di And Δ i s3 Equivalent small interference current source and equivalent direct current side impedance R of LCC converter station 12 ，L 12 And C 12 Respectively the equivalent resistance, the equivalent reactance and the equivalent capacitance of the line between the VSC-I converter station and the VSC-II converter station. R is 23 ，L 23 And C 23 Respectively, the equivalent resistance, the equivalent inductance and the equivalent capacitance, L, of the line between the VSC-II converter station and the LCC converter station p Is the direct current side smoothing reactance of the LCC converter station.
A mixed three-terminal direct-current transmission system simulation model based on LCC-VSC is established in PSCAD/EMTDC simulation software, wherein a VSC-I station adopts constant direct-current voltage control, a VSC-II station adopts constant power control, and an LCC station adopts constant direct-current control.
Referring to fig. 4, steady-state operating conditions of the system are set to be a VSC-I station absorbed power 3500mw, a VSC-II station absorbed power 1500mw, an lcc station emitted power 5000MW, and a dc voltage of 800kV. Under the steady-state working condition of the system, the VSC-II station raises the absorbed power to 2000MW, the system can keep stable operation, and the accuracy of the built model is verified. The dc voltage and current of the system are shown in fig. 4.
PSCAD simulation analysis shows that when LCC adopts traditional direct current control, the system is unstable when the absorption power of the VSC-II station is increased to 4000 MW. This is improved by using an adaptive virtual impedance in the control system of the LCC and observing the system voltage and current, as compared to when not improved.
Referring to fig. 5, simulation is performed in the PSCAD, based on steady-state conditions, the absorbed power of the fixed power station is increased to 4000mw at 3s, and the LCC station uses adaptive virtual resistance control/conventional constant dc current control to observe the dc voltage and current variation at the outlet of the LCC station. As can be seen from the solid line of fig. 5, when the LCC station employs constant dc current control, the dc system is destabilized after the absorbed power of the constant power VSC station is raised to 4000 MW; however, after the LCC station adopts the self-adaptive virtual impedance control of the invention, the system can still keep stable.
In summary, the method and the system for controlling the self-adaptive virtual impedance of the LCC converter station according to the present invention can adjust the damping effect according to the dc current measurement value of the LCC converter station, and compared with the conventional LCC converter station controlled by constant dc current, the method effectively improves the small signal stability of the system.
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 so forth) 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.
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.
Claims (9)
1. An adaptive virtual impedance control method for an LCC converter station is characterized by comprising the following steps:
s1, determining cutoff frequency omega of used adaptive virtual impedance direct-current component filtering link according to alternating-current side power frequency angular frequency of LCC converter station control system in LCC-VSC hybrid direct-current transmission system c Using a high-pass filter as a link for filtering the direct-current component of the self-adaptive virtual impedance according to the cut-off frequency omega c Obtaining a link for filtering direct current components;
s2, determining a direct current reference value of an LCC converter station control system in the LCC-VSC hybrid direct current transmission system;
s3, when the LCC converter station control system operates in a steady state, the virtual impedance effect is maximum; when the LCC converter station control system is in a direct current transmission system starting state, the virtual impedance effect is minimum; when the LCC converter station control system operates in a steady state, the derivative of the virtual impedance relative to the direct-current side current measurement value of the LCC converter station control system is 0 and serves as a boundary condition, and the impedance function type of the self-adaptive virtual impedance used in the LCC converter station control system is determined;
s4, determining an impedance function of the self-adaptive virtual impedance according to the boundary condition obtained in the step S3, the impedance function type and the direct current reference value of the LCC converter station obtained in the step S2;
s5, determining the feedforward gain of the self-adaptive virtual impedance control according to the impedance function obtained in the step S4 and the filtered direct-current component link obtained in the step S1; and the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct current transmission system is realized by controlling the feedforward gain.
2. The method of claim 1, wherein in step S1, the frequency domain for filtering out DC component is
s is a frequency domain variable.
3. Method according to claim 2, characterized in that the cut-off frequency ω is c Less than the power frequency angular frequency.
4. Method according to claim 1, characterized in that in step S2, the direct current reference value i dcref The calculation is as follows:
wherein, P LCCref Rated power, U, of LCC converter station dcref The voltage is rated for the dc side of the LCC converter station.
5. The method according to claim 1, wherein in step S3, the impedance function type of the adaptive virtual impedance is a quadratic function type, and the boundary conditions of the quadratic function type construction are specifically: r (i) dc ＝0)＝0，R(i dc ＝i dcref ) =1 and R' (i) dc ＝i dcref )＝0，i dcref Is a DC current reference value i dc For direct currents, R is the adaptive virtual impedance with respect to the direct current i dc Impedance function ofAnd (4) counting.
6. Method according to claim 1, characterized in that in step S4, the direct current i is applied dc Is equal to the reference value i of the direct current dcref Adaptive virtual impedance function R (i) dc ) The control degenerates into virtual impedance control of a constant impedance coefficient; in shifting from steady state, the virtual impedance function R (i) is adapted dc ) Control degenerates to conventional constant dc current control.
7. The method of claim 6, wherein the adaptive virtual impedance function R (i) is determined using a quadratic function to construct the impedance function R term dc ) Comprises the following steps:
wherein i dcref Is a DC current reference value, i dc Is a direct current.
8. The method according to claim 1, wherein in step S5, a product of the adaptive virtual impedance function and the filtered dc link is used as a feed-forward gain of the dc current measurement value, the feed-forward gain is fed back to a constant dc current control link of the LCC converter station control system, a firing angle command value is obtained through a PI controller, and the firing angle command value is output to thyristors of each bridge arm to realize alternate turn-on.
9. An LCC converter station adaptive virtual impedance control system, comprising:
the frequency module is used for determining the cutoff frequency omega of the used adaptive virtual impedance direct-current component filtering link according to the alternating-current side power frequency angular frequency of the LCC converter station control system in the LCC-VSC hybrid direct-current transmission system c A high-pass filter is used as a link for filtering out direct-current components of the self-adaptive virtual impedance according to the cut-off frequency omega c Obtaining a link for filtering direct current components;
the calculation module is used for determining a direct current reference value of an LCC converter station in the LCC-VSC hybrid direct current transmission system;
the boundary module is used for maximizing the virtual impedance effect when the LCC converter station control system operates in a steady state; when the LCC converter station control system is in a direct current transmission system starting state, the virtual impedance effect is minimum; when the LCC converter station control system operates in a steady state, the derivative of the virtual impedance relative to the LCC direct current side current measurement value is 0 and serves as a boundary condition, and the impedance function type of the self-adaptive virtual impedance used in the LCC converter station control system is determined;
the impedance module is used for determining an impedance function of the self-adaptive virtual impedance according to the boundary condition obtained by the boundary module, the impedance function type and the direct current reference value of the LCC converter station obtained by the boundary module;
the control module determines the feedforward gain of the self-adaptive virtual impedance control according to the impedance function obtained by the impedance module and the filtered direct-current component link obtained by the frequency module; and the self-adaptive virtual impedance control of the LCC side in the LCC-VSC hybrid direct current transmission system is realized by controlling the feedforward gain.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110580711.0A CN113300402B (en) | 2021-05-26 | 2021-05-26 | Self-adaptive virtual impedance control method and system for LCC converter station |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110580711.0A CN113300402B (en) | 2021-05-26 | 2021-05-26 | Self-adaptive virtual impedance control method and system for LCC converter station |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113300402A CN113300402A (en) | 2021-08-24 |
| CN113300402B true CN113300402B (en) | 2023-01-24 |
Family
ID=77325331
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110580711.0A Active CN113300402B (en) | 2021-05-26 | 2021-05-26 | Self-adaptive virtual impedance control method and system for LCC converter station |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113300402B (en) |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06175705A (en) * | 1992-12-07 | 1994-06-24 | Matsushita Electric Works Ltd | Impedance control method |
| CN104092242A (en) * | 2014-07-15 | 2014-10-08 | 上海电力学院 | Inverter parallel control method based on controllable virtual impedance |
| CN104716886A (en) * | 2015-03-31 | 2015-06-17 | 西安交通大学 | Virtual impedance voltage converter-based control method of virtual synchronous motor |
| CN107658904A (en) * | 2017-10-30 | 2018-02-02 | 浙江大学 | Consider the impedance self-adaptive power decoupled control method that virtual synchronous machine generator rotor angle influences |
| CN108306329A (en) * | 2018-02-28 | 2018-07-20 | 湖南大学 | The positive damping of HVDC transmission system reconstructs impedance stabilization control method |
| CN108429281A (en) * | 2018-03-15 | 2018-08-21 | 上海电力学院 | A kind of LCL type gird-connected inverter parallel virtual impedance adjustment |
| CN108667029A (en) * | 2018-06-12 | 2018-10-16 | 湖南大学 | A kind of connection in series-parallel impedance remodeling procedure of smooth busbar voltage |
| CN108767873A (en) * | 2018-05-23 | 2018-11-06 | 湖南大学 | A kind of highly reliable damping remodeling procedure of large size new energy power station |
| CN110739678A (en) * | 2018-07-20 | 2020-01-31 | 华北电力大学（保定） | Control method for series virtual impedance of grid-connected converters |
| CN112271733A (en) * | 2020-11-11 | 2021-01-26 | 南方电网科学研究院有限责任公司 | Harmonic suppression method for direct-current loop of 12-pulse high-voltage converter system and related device |
| CN112803383A (en) * | 2020-12-30 | 2021-05-14 | 佛山科学技术学院 | DC micro-grid overcurrent suppression method and system of self-adaptive virtual impedance |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105932678B (en) * | 2016-06-07 | 2018-07-06 | 湖南大学 | A kind of virtual impedance integrated control method of eletric power induction filtering system |
| EP3376627B1 (en) * | 2017-03-14 | 2021-04-28 | ABB Schweiz AG | Method and control system for controlling a power converter |
| CN110829480A (en) * | 2019-11-07 | 2020-02-21 | 国网江苏省电力有限公司经济技术研究院 | Control strategy suitable for LCC-MMC hybrid cascade converter station parallel MMC unit |
-
2021
- 2021-05-26 CN CN202110580711.0A patent/CN113300402B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06175705A (en) * | 1992-12-07 | 1994-06-24 | Matsushita Electric Works Ltd | Impedance control method |
| CN104092242A (en) * | 2014-07-15 | 2014-10-08 | 上海电力学院 | Inverter parallel control method based on controllable virtual impedance |
| CN104716886A (en) * | 2015-03-31 | 2015-06-17 | 西安交通大学 | Virtual impedance voltage converter-based control method of virtual synchronous motor |
| CN107658904A (en) * | 2017-10-30 | 2018-02-02 | 浙江大学 | Consider the impedance self-adaptive power decoupled control method that virtual synchronous machine generator rotor angle influences |
| CN108306329A (en) * | 2018-02-28 | 2018-07-20 | 湖南大学 | The positive damping of HVDC transmission system reconstructs impedance stabilization control method |
| CN108429281A (en) * | 2018-03-15 | 2018-08-21 | 上海电力学院 | A kind of LCL type gird-connected inverter parallel virtual impedance adjustment |
| CN108767873A (en) * | 2018-05-23 | 2018-11-06 | 湖南大学 | A kind of highly reliable damping remodeling procedure of large size new energy power station |
| CN108667029A (en) * | 2018-06-12 | 2018-10-16 | 湖南大学 | A kind of connection in series-parallel impedance remodeling procedure of smooth busbar voltage |
| CN110739678A (en) * | 2018-07-20 | 2020-01-31 | 华北电力大学（保定） | Control method for series virtual impedance of grid-connected converters |
| CN112271733A (en) * | 2020-11-11 | 2021-01-26 | 南方电网科学研究院有限责任公司 | Harmonic suppression method for direct-current loop of 12-pulse high-voltage converter system and related device |
| CN112803383A (en) * | 2020-12-30 | 2021-05-14 | 佛山科学技术学院 | DC micro-grid overcurrent suppression method and system of self-adaptive virtual impedance |
Non-Patent Citations (4)
| Title |
|---|
| A Control Method for Parallel Inverter with Adaptive Virtual Impedance;Ben Nie 等;《2018 5th International Conference on Systems and Informatics (ICSAI)》;20190103;全文 * |
| A New Adaptive Virtual Impedance based Fault Current Limiter for Converters;Siavash Beheshtaein 等;《2019 IEEE Energy Conversion Congress and Exposition (ECCE)》;20191128;全文 * |
| 一种考虑累计调节量的虚拟同步机准同期方法;王嘉乐 等;《电力电子技术》;20210131;全文 * |
| 基于自适应虚拟阻抗改进无功环路的虚拟同步功率解耦控制策略;李旭枫 等;《电网技术》;20191031;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113300402A (en) | 2021-08-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109149620B (en) | Self-energy-storage multi-terminal flexible-straight system control method and system | |
| CN109980657B (en) | Method for analyzing influence of fixed reactive power outer loop on stability of converter grid-connected system | |
| CN111478356A (en) | Control parameter optimization design method for multi-terminal flexible direct current transmission system | |
| Cai et al. | Research on an improved droop control strategy for soft open point | |
| Shi et al. | Improved comprehensive energy-based control for MMC-HVDC system | |
| Li et al. | Small-signal stability modeling for MMC-based DC grids with voltage slope control and influence analysis of parameters | |
| CN113300402B (en) | Self-adaptive virtual impedance control method and system for LCC converter station | |
| CN109861226A (en) | A kind of LCL filter design method of complex optimum harmonic stability and damping loss | |
| CN111651947B (en) | Impedance ratio stability judgment method suitable for distributed energy storage system | |
| CN117973096B (en) | Direct-drive wind farm parallel simulation method, system, terminal and medium based on double-layer network division | |
| CN109149981B (en) | A kind of Multipurpose Optimal Method based on genetic algorithm suitable for MMC | |
| CN112039105A (en) | Alternating current power grid frequency oscillation suppression method for high-voltage direct current transmission line interconnection | |
| CN113872189B (en) | Equivalent PLL (phase locked loop) analysis method for low-frequency oscillation characteristics when VSC (Voltage Source converter) is connected into weak power grid | |
| CN115730468A (en) | Method, system and device for hybrid control of direct-current side voltage of network-structured type converter | |
| Huang et al. | Generalized VSG Control Strategy for Active Power Transient Characteristic Optimization of Voltage Source Inverter | |
| Dai et al. | Virtual Resistor/Capacitor Droop Control based Power Allocation Strategy for Virtual Synchronous Generator | |
| Fang et al. | Analysis of Additional Damping Control Strategy and Parameter Optimization for Improving Small Signal Stability of VSC-HVDC System | |
| Wang et al. | Load stability analysis of Kazakhstan photovoltaic power system based on data visualization | |
| CN113972676B (en) | Distributed BESS coordination control method for improving transient stability of power system | |
| CN117952056B (en) | Parameter design method and device of photovoltaic inverter system and electronic equipment | |
| Zhou et al. | Comparison of Effects of Different Fault Current Limiting Control Strategies on Transient Synchronization Stability of Virtual Synchronous Inverters | |
| Wang et al. | Small Signal Stability Analysis of Micro-source Inverter System in Grid-connected Series Micro-grid | |
| CN117977682A (en) | Photovoltaic power generation system and alternating current fault ride-through method and device | |
| Weian et al. | Transient Damping Optimization Strategy for Active Power Response of VSG in Grid Connected Energy Storage Converter | |
| CN116526509A (en) | Droop control voltage frequency stable control method for energy storage voltage type converter in micro-grid based on cooperative control theory |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20231225 Address after: 710049 No. 28 West Xianning Road, Shaanxi, Xi'an Patentee after: XI'AN JIAOTONG University Patentee after: STATE GRID ELECTRIC POWER RESEARCH INSTITUTE Co.,Ltd. Address before: 710049 No. 28 West Xianning Road, Shaanxi, Xi'an Patentee before: XI'AN JIAOTONG University Patentee before: NARI TECHNOLOGY Co.,Ltd. |