CN117526319B - Multi-converter cooperative control method for restraining broadband oscillation and related device - Google Patents
Multi-converter cooperative control method for restraining broadband oscillation and related device Download PDFInfo
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Abstract
The invention provides a multi-converter cooperative control method for restraining broadband oscillation and a related device. The method comprises the following steps: establishing a small signal model of a multi-scale standard closed-loop feedback system containing a multi-power electronic converter system; calculating a system robust stability margin based on the established small signal model of the multi-scale standard closed loop feedback system; based on the calculated system robust stability margin, solving the robust stability margin sensitivity and gradient field of different control parameters, and solving a control parameter set with the largest influence on the system stability margin according to the gradient field; and according to the solved robust stability margin parameter sensitivity and gradient field, changing a plurality of control parameters in the control parameter set, and calculating an optimal parameter solution for enabling the system to meet the maximum stability margin by applying an iterative algorithm of incremental search. The invention effectively increases the stability margin of the system and solves the problem of restraining the broadband oscillation of the system caused by insufficient stability margin.
Description
Technical Field
The invention relates to the field of novel power system stability analysis, in particular to a multi-converter cooperative control method for restraining broadband oscillation and a related device.
Background
The power electronic converter is used as a core device of new energy equipment, the problem of small interference and instability of the system caused by the power electronic converter is outstanding, broadband oscillation accidents frequently occur, the improvement of the new energy duty ratio is seriously restricted, and the power electronic converter is one of main obstacles faced in the construction of a novel power system. Many researchers have developed a series of studies on the measure of suppression of broadband oscillations. The current method for suppressing broadband oscillation mainly comprises the following two methods:
1. additional damping control: the additional damping control is generally based on a state space model or an impedance model of the system, and a superior key feedback signal and an output signal additional position are selected to design a damping controller of the system. In the prior art, a damping controller is added based on a state space model, so that characteristic roots of a system are configured, and oscillation suppression is realized; damping control is added based on an impedance model, and the method realizes impedance remodelling through transfer function design, changes the position of a resonance point or increases the phase margin of a system, so as to inhibit oscillation.
2. Optimizing and designing control parameters: at present, the parameter setting method of the PSS stabilizer of the traditional synchronous machine is used for the control parameter design and setting of the new energy equipment: before the new energy equipment leaves the factory, engineers apply a pole allocation method (setting ideal characteristic roots) or a phase compensation method (setting damping ratio) to design control parameters for a single machine system; and then, in the system construction and debugging stage, partial control parameters in the multi-machine system are set through a trial-and-error method (a large number of simulation experiments). Obviously, the method is difficult to obtain optimal control parameters, and when the system structure and the operating point are changed, the system is easy to be unstable due to insufficient stability margin, poor robustness and the like. The lack of advanced multi-equipment stable control parameter design and setting methods brings great difficulty to operation scheduling personnel of a power grid and manufacturers of fans and photovoltaics. Therefore, in the prior art, a sensitivity analysis result based on modal analysis in a new energy multi-machine system is proposed, and a heuristic optimization algorithm, a system coordination design algorithm and the like are applied to perform phase compensation on a subsystem with high sensitivity, so that setting of key control parameters is realized.
The prior art has the following defects:
(1) When additional damping control is performed on a specific unit, the actual oscillation frequency is not in the damping control range and greatly influences the effect of the damping controller because the actual oscillation frequency is possibly caused by the different working conditions and parameters in actual operation.
(2) The optimal design of the existing control parameters mainly starts from a single machine system, researches on a multi-machine system are less, the existing control parameter collaborative design method can enable the system to have characteristic roots with better damping under certain running conditions, but the robustness of the system is difficult to guarantee, and the risk of insufficient robustness exists for partial uncertainty parameters.
Disclosure of Invention
The invention aims to provide a multi-converter cooperative control method and a related device for inhibiting broadband oscillation, which can judge a key control parameter set influencing the stability margin of a system according to the running state, and further solve the control parameter set meeting the maximum stability margin of the system under the current running condition through an iterative algorithm, thereby inhibiting the broadband oscillation and improving the robustness of the system.
A multi-converter cooperative control method for restraining broadband oscillation comprises the following steps:
establishing a small signal model of a multi-scale standard closed-loop feedback system containing a multi-power electronic converter system, wherein the small signal model of the multi-scale standard closed-loop feedback system is expressed by a transfer function matrix;
calculating a system robust stability margin based on the established small signal model of the multi-scale standard closed loop feedback system;
based on the calculated system robust stability margin, solving the robust stability margin sensitivity and gradient field of different control parameters, and solving a control parameter set with the largest influence on the system stability margin according to the gradient field;
according to the solved robust stability margin parameter sensitivity and gradient field, changing a plurality of control parameters in the control parameter set, and calculating an optimal parameter solution for enabling the system to meet the maximum stability margin by applying an iterative algorithm of incremental search;
the system robust stability margin of the small signal model of the multi-scale standard closed loop feedback system is defined as:
；
the small signal model of the multi-scale standard closed-loop feedback system is a multi-input-multi-output standard closed-loop feedback system, the forward channel of the small signal model is a transfer function matrix P(s), and the feedback channel is a transfer function matrix C(s); for a given system G(s):
wherein the method comprises the steps ofRepresenting the maximum singular value, which is the transfer function matrix G (j omega) and the conjugate transpose G thereof * (jω) maximum eigenvalue of the product.
Further, the establishing a small signal model of the multi-scale standard closed loop feedback system with the multi-power electronic converter system specifically comprises the following steps:
aiming at direct-current voltage scale and alternating-current scale control of the converter, active or reactive power is taken as input, internal potential amplitude and phase are taken as output, and a small signal model of a multi-scale standard closed-loop feedback system containing a multi-power electronic converter system is established.
Further, the small signal model of the multi-scale standard closed loop feedback system is represented by a transfer function matrix, and specifically comprises the following steps:
the three input signals are: the input active power dynamic of the direct current network is delta P in The output active power dynamic of the alternating current network is delta P out The output ac reactive power dynamic of the ac network is Δq; the three output signals are respectively direct-current voltage dynamic delta U dc The phase dynamics Δθ and amplitude dynamics Δe of the potential in the alternating current define:
ΔP in =[ΔP in1 ΔP in2 …ΔP inN ] T ,
ΔP out =[ΔP out1 ΔP out2 …ΔP outN ] T ,
ΔQ=[ΔQ 1 ΔQ 2 …ΔQ N ] T ，
ΔU dc =[ΔU dc1 ΔU dc2 …ΔU dcN ] T ，
Δθ=[Δθ 1 Δθ 2 …Δθ N ] T ，
ΔE=[ΔE 1 ΔE 2 …ΔE N ] T ，
wherein DeltaP in1 ~ΔP inN ，ΔP out1 ~ΔP outN ，ΔU dc1 ~ΔU dcN Active power and DC voltage of the 1 st to N th converters input and output DC capacitors, respectively, deltaQ 1 ~ΔQ N Representing reactive power, delta theta, of the AC side 1 ~Δθ N ，ΔE 1 ~ΔE N Representing the phase and amplitude of the internal potential, the subscript i representing the ith current transformer;
the dynamic process of the equipment is represented by a transfer function matrix in a system with N converters, which is specifically expressed as follows:
；
the power flow in an ac network is represented by the following formula:
；
wherein matrix C(s) represents a Jacobian matrix, K Pθ 、K PE 、K Qθ 、K QE Representing four matrix elements, wherein each parameter in the matrix of the four matrix elements is obtained according to the topology of the system and the solving result of the jacobian matrix under the polar coordinates, and each coefficient is expressed as follows: when i+.j
When i=j
Wherein E is i Representing the voltage at node i, E j A voltage representing node j; g ij Representing the conductance between nodes i and j, B ij Representing the susceptance between nodes i and j, let r= [ Δp ] out ΔQ] T =[r 1 r 2 …r N ] T , y=[Δθ ΔE] T =[y 1 y 2 …y N ] T Obtaining the saidA small signal model of a multi-scale standard closed loop feedback system expressed by a transfer function matrix.
Further, the calculating the robust stability margin of the system based on the calculated robust stability margin solves the robust stability margin sensitivity and gradient field of different control parameters, and obtains a control parameter set with the largest influence on the system stability margin according to the gradient field, which specifically comprises:
according to the calculated robust stability margin, aiming at a set K of a series of control parameters needing to be set and debugged, solving the robust stability margin sensitivity of the set K respectively aiming at different control parameters in the set K, wherein the robust stability margin sensitivity of different parameters is defined as follows:
wherein the method comprises the steps of
；
Wherein, the larger the value of sen (k), the larger the influence of the control parameter on the system stability domain, which indicates that when broadband oscillation occurs, if the control parameter is set, the system stability margin will be rapidly increased, and the broadband oscillation is suppressed;
according to the sensitivity of the robust stability margin, a corresponding gradient field is drawn in matlab, and a control parameter set K with the largest influence on the stability margin of the system is obtained 0 Wherein the sensitivity sen (k) of the robust stability margin corresponding to each control parameter is equal to or greater than 0.1.
A multi-converter cooperative control apparatus for suppressing broadband oscillation, comprising:
the model building module is used for building a small signal model of a multi-scale standard closed-loop feedback system containing a multi-power electronic converter system, and the small signal model of the multi-scale standard closed-loop feedback system is represented by a transfer function matrix;
the first calculation module is used for calculating the system robust stability margin based on the established small signal model of the multi-scale standard closed-loop feedback system;
the second calculation module is used for solving the sensitivity of the robust stability margin of different control parameters and a gradient field based on the calculated robust stability margin of the system, and solving a control parameter set with the largest influence on the system stability margin according to the gradient field;
the optimal parameter solution calculation module is used for changing a plurality of control parameters in the control parameter set according to the solved robust stability margin parameter sensitivity and gradient field, and calculating an optimal parameter solution for enabling the system to meet the maximum stability margin by applying an iterative algorithm of incremental search;
the system robust stability margin of the small signal model of the multi-scale standard closed loop feedback system is defined as:
the small signal model of the multi-scale standard closed-loop feedback system is a multi-input-multi-output standard closed-loop feedback system, the forward channel of the small signal model is a transfer function matrix P(s), and the feedback channel is a transfer function matrix C(s); for a given system G(s):
wherein the method comprises the steps ofRepresenting the maximum singular value, which is the transfer function matrix G (j omega) and the conjugate transpose G thereof * (jω) maximum eigenvalue of the product.
Furthermore, the model building module is specifically used for building a multi-scale standard closed-loop feedback system small signal model containing a multi-power electronic converter system by taking active or reactive power as input and internal potential amplitude and phase as output aiming at direct-current voltage scale and alternating-current scale control of the converter.
Further, the small signal model of the multi-scale standard closed loop feedback system is represented by a transfer function matrix, and specifically comprises the following steps:
the three input signals are: the input active power dynamic of the direct current network is delta P in The output active power dynamic of the alternating current network is delta P out The output ac reactive power dynamic of the ac network is Δq; the three output signals are respectively direct-current voltage dynamic delta U dc The phase dynamics Δθ and amplitude dynamics Δe of the potential in the alternating current define:
ΔP in =[ΔP in1 ΔP in2 …ΔP inN ] T ,
ΔP out =[ΔP out1 ΔP out2 …ΔP outN ] T ,
ΔQ=[ΔQ 1 ΔQ 2 …ΔQ N ] T ，
ΔU dc =[ΔU dc1 ΔU dc2 …ΔU dcN ] T ，
Δθ=[Δθ 1 Δθ 2 …Δθ N ] T ，
ΔE=[ΔE 1 ΔE 2 …ΔE N ] T ，
wherein DeltaP in1 ~ΔP inN ，ΔP out1 ~ΔP outN ，ΔU dc1 ~ΔU dcN Active power and DC voltage of the 1 st to N th converters input and output DC capacitors, respectively, deltaQ 1 ~ΔQ N Representing reactive power, delta theta, of the AC side 1 ~Δθ N ，ΔE 1 ~ΔE N Representing the phase and amplitude of the internal potential, the subscript i representing the ith current transformer;
the dynamic process of the equipment is represented by a transfer function matrix in a system with N converters, which is specifically expressed as follows:
the power flow in an ac network is represented by the following formula:
；
wherein matrix C(s) represents a Jacobian matrix, K Pθ 、K PE 、K Qθ 、K QE Representing four matrix elements, wherein each parameter in the matrix of the four matrix elements is obtained according to the topology of the system and the solving result of the jacobian matrix under the polar coordinates, and each coefficient is expressed as follows: when i+.j
When i=j
Wherein E is i Representing the voltage at node i, E j A voltage representing node j; g ij Representing the conductance between nodes i and j, B ij Representing the susceptance between nodes i and j, let r= [ Δp ] out ΔQ] T =[r 1 r 2 …r N ] T , y=[Δθ ΔE] T =[y 1 y 2 …y N ] T And obtaining the small signal model of the multi-scale standard closed-loop feedback system expressed by the transfer function matrix.
Further, the second computing module is specifically configured to: according to the calculated robust stability margin, aiming at a series of sets of control parameters needing to be set and debuggedK，Respectively for the collectionKThe robust stability margin sensitivity is calculated by different control parameters in the control system, and the robust stability margin sensitivity of different parameters is defined as:
wherein the method comprises the steps of
In senk) The larger the value of (2), the control parameter versus system stability domainThe larger the influence of the control parameter is, the more the system stability margin is increased rapidly if the control parameter is set when broadband oscillation occurs, and the broadband oscillation is restrained;
according to the sensitivity of the robust stability margin, a corresponding gradient field is drawn in matlab, and a control parameter set with the largest influence on the stability margin of the system is obtainedK 0 Wherein the robust stability margin sensitivity sen corresponding to each control parameterk)≥0.1。
A multi-converter cooperative control system for suppressing wideband oscillations, comprising: a computer readable storage medium and a processor;
the computer-readable storage medium is for storing executable instructions;
the processor is configured to read executable instructions stored in the computer readable storage medium and execute the method for controlling the multi-converter in coordination with suppressing wideband oscillation.
A non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the method of multi-converter cooperative control for suppressing wideband oscillations.
The invention establishes a small signal model of a multi-scale standard closed loop feedback system containing a multi-power electronic converter system, evaluates the robust stability margin of a multi-input multi-output system, solves the sensitivity and gradient field of the robust stability margin of different control parameters, and can further apply an iterative algorithm to obtain an optimal parameter solution which enables the system to meet the maximum stability margin; in the method, the robust stability margin is applied to the multi-equipment cooperative control method of the power electronic converter, when the system generates broadband oscillation, the stability margin of the system is inevitably insufficient, the key control parameter set influencing the stability margin of the system can be judged according to the result of sensitivity, the control parameter set meeting the maximum stability margin of the system under the running condition is further solved through an iterative algorithm, the original control parameters of the multi-equipment are adjusted to be optimal parameters, the oscillation is eliminated, and the broadband oscillation is restrained.
Drawings
Fig. 1 is a schematic structural diagram of a small signal model of a multi-scale standard closed-loop feedback system with a multi-power electronic converter system, which is built in an embodiment of the invention;
FIG. 2 is a flow chart of an algorithm for solving an optimal set of parameters according to the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The embodiment of the invention provides a multi-converter cooperative control method for inhibiting broadband oscillation, which comprises the following steps:
step (1): establishing a small signal model of a multi-scale standard closed-loop feedback system containing a multi-power electronic converter system, wherein the small signal model of the multi-scale standard closed-loop feedback system is represented by a transfer function matrix as shown in fig. 1; the specific implementation steps of the step (1) are as follows:
aiming at direct-current voltage scale and alternating-current scale control of the converter, active or reactive power is taken as input, internal potential amplitude and phase are taken as output, and a small signal model of a multi-scale standard closed-loop feedback system containing a multi-power electronic converter system is established. And the small signal model of the multi-scale standard closed loop feedback system is expressed by a transfer function matrix, and specifically comprises the following steps:
the three input signals are: the input active power dynamic of the direct current network is delta P in The output active power dynamic of the alternating current network is delta P out The output ac reactive power dynamic of the ac network is Δq; the three output signals are respectively direct-current voltage dynamic delta U dc The phase dynamics Δθ and amplitude dynamics Δe of the potential in the alternating current define:
ΔP in =[ΔP in1 ΔP in2 …ΔP inN ] T ,
ΔP out =[ΔP out1 ΔP out2 …ΔP outN ] T ,
ΔQ=[ΔQ 1 ΔQ 2 …ΔQ N ] T ，
ΔU dc =[ΔU dc1 ΔU dc2 …ΔU dcN ] T ，
Δθ=[Δθ 1 Δθ 2 …Δθ N ] T ，
ΔE=[ΔE 1 ΔE 2 …ΔE N ] T ，
wherein DeltaP in1 ~ΔP inN ，ΔP out1 ~ΔP outN ，ΔU dc1 ~ΔU dcN Active power and DC voltage of the 1 st to N th converters input and output DC capacitors, respectively, deltaQ 1 ~ΔQ N Representing reactive power, delta theta, of the AC side 1 ~Δθ N ，ΔE 1 ~ΔE N Representing the phase and amplitude of the internal potential, the subscript i representing the ith current transformer;
the dynamic process of the equipment is represented by a transfer function matrix in a system with N converters, which is specifically expressed as follows:
the power flow in an ac network is represented by the following formula:
wherein matrix C(s) represents a Jacobian matrix, K Pθ 、K PE 、K Qθ 、K QE Representing four matrix elements, wherein each parameter in the matrix of the four matrix elements is obtained according to the topology of the system and the solving result of the jacobian matrix under the polar coordinates, and each coefficient is expressed as follows: when i+.j
When i=j
Wherein E is i Representing the voltage at node i, E j A voltage representing node j; g ij Representing the conductance between nodes i and j, B ij Representing the susceptance between nodes i and j, let r= [ Δp ] out ΔQ] T =[r 1 r 2 …r N ] T , y=[Δθ ΔE] T =[y 1 y 2 …y N ] T And obtaining the small signal model of the multi-scale standard closed-loop feedback system expressed by the transfer function matrix.
Step (2): and (3) solving a system robust stability margin based on the standard feedback system model expressed by the transfer function matrix established in the step (1).
The system robust stability margin of the small signal model of the multi-scale standard closed loop feedback system is defined as:
the small signal model of the multi-scale standard closed-loop feedback system is a multi-input-multi-output standard closed-loop feedback system, the forward channel of the small signal model is a transfer function matrix P(s), and the feedback channel is a transfer function matrix C(s); for a given system G(s):
wherein the method comprises the steps ofRepresenting the maximum singular value, which is the transfer function matrix G (j omega) and the conjugate transpose G thereof * (jω) maximum eigenvalue of the product.
Step (3): and (3) solving the sensitivity of the robust stability margin of different control parameters and a gradient field based on the system robust stability margin calculated in the step (2), and solving a control parameter set with the greatest influence on the system stability margin according to the gradient field.
The specific implementation steps of the step (3) are as follows:
according to the calculated robust stability margin, aiming at a set K of a series of control parameters needing to be set and debugged, solving the robust stability margin sensitivity of the set K respectively aiming at different control parameters in the set K, wherein the robust stability margin sensitivity of different parameters is defined as follows:
wherein the method comprises the steps of
Wherein, the larger the value of sen (k), the larger the influence of the control parameter on the system stability domain, which indicates that when broadband oscillation occurs, if the control parameter is set, the system stability margin will be rapidly increased, and the broadband oscillation is suppressed;
according to the sensitivity of the robust stability margin, a corresponding gradient field is drawn in matlab, and a control parameter set K with the largest influence on the stability margin of the system is obtained 0 Wherein the sensitivity sen (k) of the robust stability margin corresponding to each control parameter is equal to or greater than 0.1.
Step (4): and (3) according to the calculated robust stability margin parameter sensitivity and gradient field result, changing a plurality of parameters with larger sensitivity, and calculating an optimal parameter solution for enabling the system to meet the maximum stability margin by applying an iterative algorithm of incremental search.
The overall solution process is shown in fig. 2, and specifically includes the following 9 steps:
step 1: an interaction path with a smaller robust stability margin b [ P(s), C(s) ] is selected.
Step 2: calculating the sensitivity of the control parameter k in a nominal system。
Step 3: judgingIf the ratio is greater than or equal to 0.1, the step 5 is carried out if the ratio is satisfied, and if the ratio is not satisfied, the step 4 is carried out.
Step 4: another control parameter is selected to enter step 2.
Step 5: changing the control parameter k, inputting k according to some iterative algorithm 1 ,k 2 And satisfy k 1 <k 0 <k 2 。
Step 6: get K into set K 0 。
Step 7: calculation of K 0 System robust stability margin at time。
Step 8: judgingWhether or not greater than b [ P(s), C(s)]If yes, the process proceeds to step 8, and if not, the process returns to step 5.
Step 9: results are obtained inThe parameter set at the time is K 0 And (5) the optimized parameter set.
The embodiment of the invention also provides a multi-converter cooperative control device for inhibiting broadband oscillation, which comprises the following components:
the model building module is used for building a small signal model of a multi-scale standard closed-loop feedback system containing a multi-power electronic converter system, and the small signal model of the multi-scale standard closed-loop feedback system is represented by a transfer function matrix;
the first calculation module is used for calculating the system robust stability margin based on the established small signal model of the multi-scale standard closed-loop feedback system;
the second calculation module is used for solving the sensitivity of the robust stability margin of different control parameters and a gradient field based on the calculated robust stability margin of the system, and solving a control parameter set with the largest influence on the system stability margin according to the gradient field;
and the optimal parameter solution calculation module is used for changing a plurality of control parameters in the control parameter set according to the solved robust stability margin parameter sensitivity and gradient field, and calculating an optimal parameter solution for enabling the system to meet the maximum stability margin by applying an iterative algorithm of incremental search.
The invention establishes a small signal model of a multi-scale standard closed loop feedback system containing a multi-power electronic converter system, evaluates the robust stability margin of a multi-input multi-output system, solves the sensitivity and gradient fields of the robust stability margin of different control parameters, and can further apply an iterative algorithm to obtain an optimal parameter solution which enables the system to meet the maximum stability margin. In the method, the robust stability margin is applied to the cooperative control method of the multiple devices of the power electronic converter, when the system generates broadband oscillation, the stability margin of the system is inevitably insufficient, the key control parameter set influencing the stability margin of the system can be judged according to the running state, the control parameter set meeting the maximum stability margin of the system under the running condition is further solved through an iterative algorithm, the original control parameters of the multiple devices are adjusted to optimal parameters, the oscillation is eliminated, and the broadband oscillation is restrained.
Another embodiment of the present invention provides a multi-converter cooperative control system for suppressing broadband oscillation, including: a computer readable storage medium and a processor;
the computer-readable storage medium is for storing executable instructions;
the processor is configured to read executable instructions stored in the computer readable storage medium and execute the method for controlling the multi-converter in coordination with suppressing wideband oscillation.
Another embodiment of the present invention provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the method of multi-variator cooperative control that suppresses wideband oscillations.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the 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 foregoing is merely illustrative embodiments of the present invention, and the present invention is not limited thereto, and any changes or substitutions that may be easily contemplated by those skilled in the art within the scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.
Claims (6)
1. A method for cooperative control of a multi-converter for suppressing broadband oscillation, comprising the steps of:
establishing a small signal model of a multi-scale standard closed-loop feedback system containing a multi-power electronic converter system, wherein the small signal model of the multi-scale standard closed-loop feedback system is expressed by a transfer function matrix;
calculating a system robust stability margin based on the established small signal model of the multi-scale standard closed loop feedback system;
based on the calculated system robust stability margin, solving the robust stability margin sensitivity and gradient field of different control parameters, and solving a control parameter set with the largest influence on the system stability margin according to the gradient field;
according to the solved robust stability margin parameter sensitivity and gradient field, changing a plurality of control parameters in the control parameter set, and calculating an optimal parameter solution for enabling the system to meet the maximum stability margin by applying an iterative algorithm of incremental search;
the system robust stability margin of the small signal model of the multi-scale standard closed loop feedback system is defined as:
；
wherein the small signal model of the multi-scale standard closed-loop feedback system is a multi-input-multi-output standard closed-loop feedback system, and the forward channel transfer function matrix thereofP(s) The feedback channel is a transfer function matrixC(s) The method comprises the steps of carrying out a first treatment on the surface of the For a given systemG(s)：
Wherein the method comprises the steps ofRepresenting the maximum singular value, which is a transfer function matrixG(jω) To conjugate transpose ofG * (jω) The maximum eigenvalue of the product;
the method for establishing the small signal model of the multi-scale standard closed loop feedback system with the multi-power electronic converter system specifically comprises the following steps:
aiming at direct-current voltage scale and alternating-current scale control of the converter, taking active or reactive power as input and internal potential amplitude and phase as output, establishing a multi-scale standard closed-loop feedback system small signal model containing a multi-power electronic converter system;
the small signal model of the multi-scale standard closed loop feedback system is expressed by a transfer function matrix, and specifically comprises the following steps:
the three input signals are: the input active power dynamic of the direct current network is deltaP in The output active power dynamic of the alternating current network is deltaP out The output ac reactive power dynamic of the ac network is deltaQThe method comprises the steps of carrying out a first treatment on the surface of the The three output signals are respectively direct-current voltage dynamic deltaU dc Phase dynamics delta of ac internal potentialθAnd amplitude dynamics deltaEDefinition:
ΔP in =[ΔP in1 ΔP in2 …ΔP Nin ] T ,
ΔP out =[ΔP out1 ΔP out2 …ΔP Nout ] T ,
ΔQ=[ΔQ 1 ΔQ 2 …ΔQ N ] T ，
ΔU dc =[ΔU dc1 ΔU dc2 …ΔU Ndc ] T ，
Δθ=[Δθ 1 Δθ 2 …Δθ N ] T ，
ΔE=[ΔE 1 ΔE 2 …ΔE N ] T ，
in the formula deltaP in1 ~ΔP Nin ，ΔP out1 ~ΔP Nout ，ΔU dc1 ~ΔU Ndc Respectively represent 1 st to 1 stNActive power and DC voltage of input and output DC capacitors of each converter, deltaQ 1 ~ΔQ N Representing reactive power, delta at the ac sideθ 1 ~Δθ N ，ΔE 1 ~ΔE N Representing the phase and amplitude of the internal potential, subscriptiRepresents the firstiA plurality of current transformers;
the dynamic process of the equipment is represented by a transfer function matrix in a system with N converters, which is specifically expressed as follows:
the power flow in an ac network is represented by the following formula:
；
wherein the matrixC(s) Representing a jacobian matrix of the matrix,K Pθ 、K PE 、K Qθ 、K QE representing four matrix elements, wherein each parameter in the matrix of the four matrix elements is obtained according to the topology of the system and the solving result of the jacobian matrix under the polar coordinates, and each coefficient is expressed as follows: when i+.j
When i=j
Wherein E is i Representative nodeiVoltage of E j A voltage representing node j; g ij Representative nodeiAnd j, B ij Representative nodeiSusceptance between j, letr=[ΔP out ΔQ] T =[r 1 r 2 …r N ] T ,y=[Δθ ΔE] T =[y 1 y 2 …y N ] T And obtaining the small signal model of the multi-scale standard closed-loop feedback system expressed by the transfer function matrix.
2. A multi-converter cooperative control method for suppressing broadband oscillation as defined in claim 1, wherein: the robust stability margin of the system based on calculation is used for solving the sensitivity and gradient field of the robust stability margin of different control parameters, and the control parameter set with the largest influence on the system stability margin is obtained according to the gradient field, and the method specifically comprises the following steps:
according to the calculated robust stability margin, aiming at a series of sets of control parameters needing to be set and debuggedK，Respectively for the collectionKThe robust stability margin sensitivity is calculated by different control parameters in the control system, and the robust stability margin sensitivity of different parameters is defined as:
wherein the method comprises the steps of
In senk) The larger the value of (2), the larger the influence of the control parameter on the stability domain of the system, indicating that in the event of broadband oscillationsIf the control parameters are set, the stability margin of the system can be rapidly increased, and broadband oscillation is restrained;
according to the sensitivity of the robust stability margin, a corresponding gradient field is drawn in matlab, and a control parameter set with the largest influence on the stability margin of the system is obtainedK 0 Wherein the robust stability margin sensitivity sen corresponding to each control parameterk)≥0.1。
3. A multi-converter cooperative control device for suppressing broadband oscillation, characterized in that: comprising the following steps:
the model building module is used for building a small signal model of a multi-scale standard closed-loop feedback system containing a multi-power electronic converter system, and the small signal model of the multi-scale standard closed-loop feedback system is represented by a transfer function matrix;
the first calculation module is used for calculating the system robust stability margin based on the established small signal model of the multi-scale standard closed-loop feedback system;
the second calculation module is used for solving the sensitivity of the robust stability margin of different control parameters and a gradient field based on the calculated robust stability margin of the system, and solving a control parameter set with the largest influence on the system stability margin according to the gradient field;
the optimal parameter solution calculation module is used for changing a plurality of control parameters in the control parameter set according to the solved robust stability margin parameter sensitivity and gradient field, and calculating an optimal parameter solution for enabling the system to meet the maximum stability margin by applying an iterative algorithm of incremental search;
the system robust stability margin of the small signal model of the multi-scale standard closed loop feedback system is defined as:
；
wherein the small signal model of the multi-scale standard closed-loop feedback system is a multi-input-multi-output standard closed-loop feedback system, and the forward channel transfer function matrix thereofP(s) The feedback channel is a transfer function matrixC(s) The method comprises the steps of carrying out a first treatment on the surface of the For a given systemG(s)：
Wherein the method comprises the steps ofRepresenting the maximum singular value, which is a transfer function matrixG(jω) To conjugate transpose ofG * (jω) The maximum eigenvalue of the product;
the model building module is specifically used for building a multi-scale standard closed-loop feedback system small signal model containing a multi-power electronic converter system by taking active or reactive power as input and internal potential amplitude and phase as output aiming at direct-current voltage scale and alternating-current scale control of the converter;
the small signal model of the multi-scale standard closed loop feedback system is expressed by a transfer function matrix, and specifically comprises the following steps:
the three input signals are: the input active power dynamic of the direct current network is deltaP in The output active power dynamic of the alternating current network is deltaP out The output ac reactive power dynamic of the ac network is deltaQThe method comprises the steps of carrying out a first treatment on the surface of the The three output signals are respectively direct-current voltage dynamic deltaU dc Phase dynamics delta of ac internal potentialθAnd amplitude dynamics deltaEDefinition:
ΔP in =[ΔP in1 ΔP in2 …ΔP Nin ] T ,
ΔP out =[ΔP out1 ΔP out2 …ΔP Nout ] T ,
ΔQ=[ΔQ 1 ΔQ 2 …ΔQ N ] T ，
ΔU dc =[ΔU dc1 ΔU dc2 …ΔU Ndc ] T ，
Δθ=[Δθ 1 Δθ 2 …Δθ N ] T ，
ΔE=[ΔE 1 ΔE 2 …ΔE N ] T ，
in the formula deltaP in1 ~ΔP Nin ，ΔP out1 ~ΔP Nout ，ΔU dc1 ~ΔU Ndc Respectively represent 1 st to 1 stNActive power and DC voltage of input and output DC capacitors of each converter, deltaQ 1 ~ΔQ N Representing reactive power, delta at the ac sideθ 1 ~Δθ N ，ΔE 1 ~ΔE N Representing the phase and amplitude of the internal potential, subscriptiRepresents the firstiA plurality of current transformers;
the dynamic process of the equipment is represented by a transfer function matrix in a system with N converters, which is specifically expressed as follows:
the power flow in an ac network is represented by the following formula:
；
wherein the matrixC(s) Representing a jacobian matrix of the matrix,K Pθ 、K PE 、K Qθ 、K QE representing four matrix elements, wherein each parameter in the matrix of the four matrix elements is obtained according to the topology of the system and the solving result of the jacobian matrix under the polar coordinates, and each coefficient is expressed as follows: when i+.j
When i=j
Wherein E is i Representative nodeiVoltage of E j A voltage representing node j; g ij Representative nodeiAnd j, B ij Representative nodeiSusceptance between j, letr=[ΔP out ΔQ] T =[r 1 r 2 …r N ] T ,y=[Δθ ΔE] T =[y 1 y 2 …y N ] T And obtaining the small signal model of the multi-scale standard closed-loop feedback system expressed by the transfer function matrix.
4. A multi-converter cooperative control apparatus for suppressing broadband oscillation as defined in claim 3, wherein: the second computing module is specifically configured to: according to the calculated robust stability margin, aiming at a series of sets of control parameters needing to be set and debuggedK，Respectively for the collectionKThe robust stability margin sensitivity is calculated by different control parameters in the control system, and the robust stability margin sensitivity of different parameters is defined as:
wherein the method comprises the steps of
In senk) The larger the value of the control parameter is, the larger the influence of the control parameter on the system stability area is, which indicates that when broadband oscillation occurs, if the control parameter is set, the system stability margin is rapidly increased, and the broadband oscillation is restrained;
from finding robust stability marginSensitivity, drawing a corresponding gradient field in matlab, and obtaining a control parameter set with the greatest influence on the stability margin of the systemK 0 Wherein the robust stability margin sensitivity sen corresponding to each control parameterk)≥0.1。
5. A multi-converter cooperative control system for suppressing wideband oscillations, comprising: a computer readable storage medium and a processor;
the computer-readable storage medium is for storing executable instructions;
the processor is configured to read executable instructions stored in the computer readable storage medium and execute a multi-converter cooperative control method for suppressing broadband oscillation according to any one of claims 1-2.
6. A non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a multi-variator cooperative control method of suppressing broadband oscillations according to any one of claims 1-2.
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