CN116054120A - DC micro-grid power control method, system, equipment and storage medium - Google Patents
DC micro-grid power control method, system, equipment and storage medium Download PDFInfo
- Publication number
- CN116054120A CN116054120A CN202211511922.XA CN202211511922A CN116054120A CN 116054120 A CN116054120 A CN 116054120A CN 202211511922 A CN202211511922 A CN 202211511922A CN 116054120 A CN116054120 A CN 116054120A
- Authority
- CN
- China
- Prior art keywords
- power
- grid
- micro
- model
- output
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 65
- 238000003860 storage Methods 0.000 title claims abstract description 14
- 230000003044 adaptive effect Effects 0.000 claims abstract description 19
- 238000011217 control strategy Methods 0.000 claims abstract description 8
- 238000013501 data transformation Methods 0.000 claims abstract description 4
- 239000011159 matrix material Substances 0.000 claims description 28
- 230000006870 function Effects 0.000 claims description 13
- 230000008569 process Effects 0.000 claims description 12
- 238000004590 computer program Methods 0.000 claims description 8
- 230000008859 change Effects 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 7
- 238000004364 calculation method Methods 0.000 description 5
- 238000004146 energy storage Methods 0.000 description 5
- 238000004891 communication Methods 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 3
- 238000004088 simulation Methods 0.000 description 3
- 238000013499 data model Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 238000007665 sagging Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000006467 substitution reaction Methods 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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/10—Parallel operation of dc sources
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention relates to a direct-current micro-grid power control method, a system, equipment and a storage medium, wherein the method comprises the following steps: step S1, on the premise that line impedance influence is not ignored, a dynamic linearization model based on a distributed secondary control signal is established by utilizing input and output data of a micro-grid system, a nonlinear system is obtained through discretization, and an incremental DC micro-grid power control system model is obtained through equivalent data transformation; and S2, constructing a model-free secondary control strategy based on the adaptive observer, estimating a secondary control signal, and distributing load power according to the rated capacity of the distributed power supply by combining a voltage-power droop control method based on the secondary control signal. Compared with the prior art, the method of the invention does not need priori knowledge of a controlled system, can realize accurate distribution of load power, ensures that the voltage of the direct current bus is basically maintained around a rated value, ensures good power supply quality of a micro-grid, and has the advantage of high robustness.
Description
Technical Field
The invention relates to the technical field of micro-grid power control, in particular to a direct-current micro-grid power control method, a system, equipment and a storage medium.
Background
The ability of a microgrid to efficiently integrate distributed power sources (distribution generator, DG), energy storage and controllable loads is considered to be an effective way to handle the in-situ consumption of distributed power sources, and is also an important development direction for future smartgrids. Along with the rapid development of direct current power sources such as photovoltaic, energy storage equipment and fuel cells in a micro-grid system and the massive access of direct current loads such as electric automobiles and LED illumination, the direct current micro-grid has the advantages of low cost, small loss and the like, and meanwhile, the alternating current problems such as reactive power compensation and frequency stability do not need to be considered, so that the direct current micro-grid is paid attention to and researched.
The traditional droop control mode cannot ensure that each distributed power supply accurately distributes load power according to the rated capacity of each distributed power supply, and the inherent voltage deviation reduces the quality of the power supply voltage of the direct-current micro-grid system. Hierarchical control is the primary control mode of the microgrid. Wherein the primary control is droop control, and the secondary control is used for compensating power distribution errors and voltage deviations caused by the primary droop control.
However, since model information such as a system structure, a system order, and the like of an actual nonlinear controlled system is unknown, it is difficult to build an accurate mathematical model.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method, a system, equipment and a storage medium for controlling the power of a direct-current micro-grid, which can realize the accurate distribution of load power, ensure that the voltage of a direct-current bus is basically maintained around a rated value and ensure the good power supply quality of the micro-grid.
The aim of the invention can be achieved by the following technical scheme:
according to a first aspect of the present invention, there is provided a direct current micro grid power control method comprising the steps of:
step S1, on the premise that line impedance influence is not ignored, a dynamic linearization model based on a distributed secondary control signal is established by utilizing input and output data of a micro-grid system, a nonlinear system is obtained through discretization, and an incremental DC micro-grid power control system model is obtained through equivalent data transformation;
and S2, constructing a model-free secondary control strategy based on the adaptive observer, estimating a secondary control signal, and distributing load power according to the rated capacity of the distributed power supply by combining a voltage-power droop control method based on the secondary control signal.
Preferably, the dc micro-grid structure in the step S1 includes a dc bus, distributed power sources, and a load, where each of the distributed power sources is connected to a common dc bus in a direct parallel manner.
Preferably, the step S1 specifically includes:
step S11, a dynamic linearization model based on a secondary control signal is established by utilizing input and output data of a micro-grid system, and a mathematical expression is as follows:
y i (t)＝f(y i (t),n i (t))
wherein n is i (t) is a secondary control signal, and f (·) is an unknown system model parameter; y is i ＝[V oi ,P oi ] T For system output vector, V oi Is the output voltage of the ith distributed power supply, P oi Output power for the ith distributed power supply;
in an island operation mode, a distributed power supply in the micro-grid is responsible for maintaining system power balance and stable direct current bus voltage, and the power balance expression of the whole system is as follows:
wherein P is pcc Is the common load on the common DC bus, P linei N is the number of distributed power supplies, which is the power loss on the line impedance;
step S12, discretizing a dynamic linearization model based on the output voltage and the output power of the online measured distributed power supply to obtain a nonlinear system:
y i (k+1)＝f(y i (k),y i (k-1),...,y i (k-d),
n i (k),n i (k-1),...,n i (k-d))
wherein d represents an unknown positive integer of the system order;
step S13, based on nonlinear system assumption, converting nonlinear system partial format linearization equivalent into an incremental DC micro-grid power control system model, wherein the expression is as follows:
in phi, phi i (k)＝[Φ i1 (k),Φ i2 (k),…,Φ iL (k)] T Is a pseudo-jacobian matrix; Δy i Adding the system output vector; u (U) i (k)＝[n i (k),n i (k-1),…,n i (k-L+1)] T ，ΔU i For the corresponding vector increment, L is a dynamic linearization constant.
Preferably, the nonlinear system in step S1 is specifically assumed to be:
suppose 1: control function f (·) is related to control input n i (k) Is continuous;
suppose 2: the system being in the generalized Lipschitz, i.e. for any of the different moments k 1 、k 2 All satisfy:
||y i (k 1 +1)-y i (k 2 +1)||≤b||U i (k 1 )-U i (k 2 )||
where b is a normal number, L is a dynamic linearization constant, U i (k)＝[n i (k),n i (k-1),…,n i (k-L+1)] T ；
When hypothesis 1 and hypothesis 2 are true, if Δu i (k) There must be a pseudo jacobian matrix Φ with i not equal to 0 i (k) So that the nonlinear system is converted into:
in phi, phi i (k)＝[Φ i1 (k),Φ i2 (k),…,Φ iL (k)] T Is a pseudo-jacobian matrix.
Preferably, the step S2 specifically includes:
step S21, constructing an adaptive observer to estimate a pseudo-Jacobian matrix phi (k), wherein the mathematical expression of the adaptive observer of the ith distributed power supply is as follows:
in the method, in the process of the invention,
is the output estimation error of the system; />
Is the system output estimated value; />
Is an estimate of the pseudo-jacobian matrix; k (K) i Is the observer gain matrix; Γ -shaped structure i (k)＝2(||ΔU i (k)||+μ i ) -1 ，μ i >0 is a weight factor for limiting the range of variation of the pseudo-jacobian matrix estimation value;
the output estimation error expression of the system is as follows:
in the method, in the process of the invention,
is the estimation error of the pseudo-jacobian matrix; f (F) i Satisfy F i ＝I-K i ，K i Is the observer gain matrix;
and S22, adopting a model-free secondary controller, and distributing load power according to the rated capacity of the distributed power supply by combining a voltage-power droop control method based on a secondary control signal.
Preferably, the step S22 is based on the secondary control signalThe pressure-power droop control method specifically comprises the following steps: each converter is directly controlled by a droop function by adopting a distributed secondary control model, and a secondary control signal n is added to the droop function of the main control layer i Wherein the mathematical expression of the droop function is:
V oi ＝V ref -m i P oi +n i
wherein V is oi Is the output voltage of the ith distributed power source DG, V ref Is the rated voltage of a direct current bus, m i Is the droop coefficient of the ith distributed power supply, n i Is the secondary control signal of the ith distributed power supply.
Preferably, the mathematical expression of the model-free secondary controller in the step S22 is:
in the method, in the process of the invention,
for the desired output of the system, α > 0 is a weighting factor and δ is a finite normal number used to limit the rate of change of the control input.
According to a second aspect of the present invention, there is provided an adaptive observer-based direct current microgrid power control system employing a method according to any one of the preceding claims, the system comprising:
the direct-current micro-grid power control model building module is used for building a direct-current micro-grid power control system model;
the self-adaptive observer is used for observing a coefficient matrix in the direct-current micro-grid power control system model;
the model-free secondary controller is used for carrying out model-free secondary control based on the coefficient matrix estimated value output by the adaptive observer and the observed data to obtain a secondary control signal;
the voltage-power droop control module is used for performing droop control according to a secondary control signal output by the model-free secondary controller to obtain load power distribution data of each distributed power supply;
and the direct-current micro-grid control module is used for controlling the power of the direct-current micro-grid according to the load power distribution data of each distributed power supply output by the voltage-power droop control module.
According to a third aspect of the present invention there is provided an electronic device comprising a memory and a processor, the memory having stored thereon a computer program, the processor implementing the method of any one of the above when executing the program.
According to a fourth aspect of the present invention, there is provided a computer readable storage medium having stored thereon a computer program which when executed by a processor implements the method of any one of the above.
Compared with the prior art, the invention has the following advantages:
the invention provides a model-free secondary control method based on a self-adaptive observer aiming at a distributed power supply of a island direct-current micro-grid, a dynamic linearization model is established by utilizing input and output data of a system, load power is distributed according to rated capacity and system bus voltage is recovered based on a model-free control strategy, and the control method does not need prior knowledge of a controlled system, has a simple structure, is easy to realize and has stronger robustness.
Drawings
FIG. 1 is a block diagram of a DC micro-grid;
FIG. 2 is a simple system architecture of a double parallel DGs;
FIG. 3 is a secondary control block diagram;
FIG. 4 is a block diagram of an RTDS-based system;
FIG. 5 is a schematic diagram of simulation results of example 1; fig. 5 (a) shows DG output power, fig. 5 (b) shows bus voltage, and fig. 5 (c) shows DG output voltage;
FIG. 6 is a schematic diagram of simulation results of example 2; fig. 6 (a) shows DG output power, fig. 6 (b) shows bus voltage, and fig. 6 (c) shows DG output voltage;
FIG. 7 is a schematic diagram of simulation results of example 3; fig. 7 (a) shows DG output power, fig. 7 (b) shows bus voltage, and fig. 7 (c) shows DG output voltage.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
Examples
The invention provides a direct-current micro-grid power model-free secondary control method based on a self-adaptive observer aiming at a island direct-current micro-grid distributed power supply. The control scheme provided by the invention does not need priori knowledge of a controlled system, has a simple structure, is easy to realize and has stronger robustness, and the method comprises the following steps:
step S1, on the premise that line impedance influence is not ignored, a dynamic linearization model based on a distributed secondary control signal is established by utilizing input and output data of a micro-grid system, a nonlinear system is obtained through discretization, and an incremental DC micro-grid power control system model is obtained through equivalent data transformation;
and S2, constructing a model-free secondary control strategy based on the adaptive observer, estimating a secondary control signal, and distributing load power according to the rated capacity of the distributed power supply by combining a voltage-power droop control method based on the secondary control signal.
Next, the method of the present invention will be described in detail.
1. DC micro-grid system
A typical microgrid system structure is shown in fig. 1, comprising a dc bus, a distributed power source (including photovoltaic, energy storage units) and a load. In the direct-current micro-grid, each distributed power source DG is typically connected to a common bus in a direct parallel manner.
In the island operation mode, the distributed power source DG in the micro grid is responsible for maintaining the system power balance and the dc bus voltage stability. The power balance of the overall system can be expressed as:
wherein P is oi For the output power, P, of the ith distributed power source DG pcc Is the common load on the common DC bus, P linei Is the power loss at the ith line impedance.
2. Traditional droop control and power allocation
The power distribution between the converters is controlled by voltage-power V-P droop, expressed as follows:
V oi ＝V ref -m i P oi (2)
wherein V is oi Is the output voltage of the ith distributed power source DG, V ref Is the rated voltage of a direct current bus, m i Is the droop coefficient of the i-th distributed power supply DG.
A simple system model of two sets of distributed power sources DGs running in parallel is shown in fig. 2. Wherein V is o1 And V o2 Output voltages of DGs, P o1 And P o2 Output powers of DGs, R line1 And R is line2 Line impedance, R, of DGs respectively load Is equivalent to load impedance, V pcc Is the DC bus voltage.
When the system is operating stably, if the influence of the line impedance is ignored, the output voltage of each distributed power source DG satisfies the relationship:
V o1 ＝V o2 ＝V pcc (3)
from the formulas (2) and (3), it is known that when the droop coefficient is set according to the rated capacity of the individual DG, the load power can be distributed according to the rated capacity ratio, that is
However, in practical applications of the micro grid, the line impedance cannot be neglected. Impedance parameters of the DG power transmission lines are generally not uniform, so that actual output voltages of the DG units of the distributed power sources are different.
Two groups of distributed power sources DG with equal rated capacity are adopted for illustration, if the same droop coefficient is selected, when the line impedance is different,
V o1 ≠V o2 ≠V pcc (5)
therefore, the conventional droop control cannot achieve accurate power distribution of each DG, subject to interference from line impedance.
3. Dynamic linearization modeling
In order to realize stable system voltage and accurate power distribution, the invention provides a novel distributed secondary control method, each converter is directly controlled by a droop function, and the overall control scheme is shown in fig. 3.
Then, a secondary control signal n is designed i To be added to the sagging function (2) of the main control layer, i.e
V oi ＝V ref -m i P oi +n i (6)
The micro grid system shown in fig. 3 may build an input-output model of the form:
y i (t)＝f(y i (t),n i (t)) (7)
wherein y is i ＝[V oi ,P oi ] T For the system output vector, f (·) is an unknown system model parameter.
The DG output voltage and power are measured on line, and the input-output model (7) can be discretized into:
where d represents the system order and is an unknown positive integer.
The nonlinear system (8) has the assumption that it can be equivalently converted into an incremental form of the data model by partial format linearization.
Suppose 1: control function f (·) is related to control input n i (k) Is continuous.
Suppose 2: the system being of the generalized Lipschitz type, i.e. for any of the different moments k 1 、k 2 All satisfy
||y i (k 1 +1)-y i (k 2 +1)||≤b||U i (k 1 )-U i (k 2 )|| (9)
Where b is a normal number, L is a dynamic linearization constant, U i (k)＝[n i (k),n i (k-1),…,n i (k-L+1)] T 。
When the above assumption is satisfied, if ΔU i (k) There must be a pseudo jacobian matrix Φ with i not equal to 0 i (k) So that the system (8) can be converted into:
in phi, phi i (k)＝[Φ i1 (k),Φ i2 (k),…,Φ iL (k)] T Is a PDD matrix.
The off-grid linearization model (10) of the microgrid system is an equivalent data model whose existence can be demonstrated by a rigorous mathematical analysis process.
4. Model-free control based on adaptive observer
Prior to designing the controller, an adaptive observer is proposed to estimate the parameter Φ (k). The structure of the ith observer measures the output voltage and power of the distributed power supply DG in the system as follows:
in the method, in the process of the invention,
is the output estimation error, +.>
Is the system output estimate,/, for>
Is the estimated value of PPD matrix, K i Is an observer gain matrix and satisfies F i ＝I-K i 。
By combining the equation (10) and the equation (11), the output estimation error of the system is given,
in the method, in the process of the invention,
is PPD parameter estimation error. The adaptive update rate of Φ (k) can then be expressed as:
wherein, Γ i (k)＝2(||ΔU i (k)||+μ i ) -1 ，μ i >0 is a weight factor for limiting the range of PPD estimate variation.
Thus, the pseudo partial derivative adaptive observer of the system model (10) is:
according to the observer (14), the model-free secondary controller of the system is as follows:
in the method, in the process of the invention,
for the desired output of the system, α > 0 is a weighting factor and δ is a finite normal number used to limit the rate of change of the control input. The stability of the model-free control closed loop system (7) can be ensured by Lyapunov stability theory.
5. Calculation case analysis
In order to verify the effectiveness of the proposed island direct current micro-grid power control strategy based on the adaptive observer, an island direct current micro-grid system containing three groups of parallel distributed power supplies (DG 1, DG2 and DG 3) and 3 resistive loads as shown in fig. 4 is built based on an RTDS (real time digital system) experimental platform, and the load power distribution conditions among distributed power supplies are unfolded and analyzed, and specific system parameters are shown in table 1.
TABLE 1
| Parameters (parameters) | Value taking |
| DG1 rated capacity (P) rate1 ) | 1kW |
| DG2 rated capacity (P) rate2 ) | 2kW |
| DG3 rated capacity (P) rate3 ) | 3kW |
| Load 1 (R) load1 ) | 100Ω |
| Load 2 (R) load2 ) | 200Ω |
| Load 3 (R) load3 ) | 100Ω |
| Line resistance R line1 | 0.3Ω |
| Line resistance R line2 | 0.9Ω |
| Line resistance R line3 | 1.5Ω |
| Rated voltage (V) ref ) | 400V |
| Maximum allowable voltage deviation | ±5％(20V) |
In the proposed model-free secondary control method, the desired output power y 1 * (k+1)＝(P ratei /∑P ratei )∑P oi (k) The desired output voltage is the nominal voltage.
Calculation example 1: DG load power distribution situation
When the micro-grid operates normally and independently, the energy storage system formed by the distributed energy storage units maintains the power balance in the system, namely in the calculation example 1, the validity of the proposed strategy is verified through the power distribution condition when the system operates in a steady state. Within 0-2s, the system operates in a conventional droop control state. As can be seen from fig. 5 (a), the load power distribution between DG cannot be distributed proportionally due to the influence of the line impedance. At 2s DGs switches to the proposed model-free control scheme. Under the proposal, the controller dynamically adjusts the actual output power of each DG through the expected output power, and realizes the proportional accurate distribution of the load power. At the same time, the desired output voltage is introduced to control the converter outlet side voltage to restore the bus voltage to the system rated voltage, as shown in fig. 5 (b) and 5 (c).
Calculation example 2: DG output variation
The present example verifies the effectiveness of the proposed model-free control strategy under DG rated capacity changes. At 5s, the rated capacity of DG1 was increased to 1.5kW, and the rated capacities of DG2 and DG3 were reduced to 1.5kW. When the DG rated capacity is changed, the model-free secondary controller can quickly adjust the load power distribution ratio, so that the DG output powers tend to be consistent, as shown in fig. 6 (a). Fig. 6 (b) and 6 (c) are system bus voltage and converter output voltage operating results. In the whole operation process, the voltage of the direct current bus is basically maintained around the rated value, and the good power supply quality of the micro-grid is ensured.
Calculation example 3: load side power surge condition
In example 3, when the load side power fluctuates, the validity of the proposed model-free secondary control is verified. Within 0-5s, the system load side only loads R load1 Normally works; at t=5s, the load side enters the load R load2 The method comprises the steps of carrying out a first treatment on the surface of the At t=10s, the load side access load R load3 . Fig. 7 is a system operation result under load side power fluctuation. As can be seen from fig. 7 (a), the load power can be distributed according to the rated capacity ratio under the proposed control strategy regardless of the load variation. In addition, during load-side power fluctuation, the bus voltage fluctuates within a reasonable voltage range, as shown in fig. 7 (b) and 7 (c).
Next, a dc micro-grid power control system based on an adaptive observer is provided, and the method is adopted, where the system includes:
the direct-current micro-grid power control model building module is used for building a direct-current micro-grid power control system model;
the self-adaptive observer is used for observing a coefficient matrix in the direct-current micro-grid power control system model;
the model-free secondary controller is used for carrying out model-free secondary control based on the coefficient matrix estimated value output by the adaptive observer and the observed data to obtain a secondary control signal;
the voltage-power droop control module is used for performing droop control according to a secondary control signal output by the model-free secondary controller to obtain load power distribution data of each distributed power supply;
and the direct-current micro-grid control module is used for controlling the power of the direct-current micro-grid according to the load power distribution data of each distributed power supply output by the voltage-power droop control module.
The electronic device of the present invention includes a Central Processing Unit (CPU) that can perform various appropriate actions and processes according to computer program instructions stored in a Read Only Memory (ROM) or computer program instructions loaded from a storage unit into a Random Access Memory (RAM). In the RAM, various programs and data required for the operation of the device can also be stored. The CPU, ROM and RAM are connected to each other by a bus. An input/output (I/O) interface is also connected to the bus.
A plurality of components in a device are connected to an I/O interface, comprising: an input unit such as a keyboard, a mouse, etc.; an output unit such as various types of displays, speakers, and the like; a storage unit such as a magnetic disk, an optical disk, or the like; and communication units such as network cards, modems, wireless communication transceivers, and the like. The communication unit allows the device to exchange information/data with other devices via a computer network, such as the internet, and/or various telecommunication networks.
The processing unit performs the respective methods and processes described above, for example, the methods S1 to S2. For example, in some embodiments, methods S1-S2 may be implemented as a computer software program tangibly embodied on a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and/or installed onto the device via the ROM and/or the communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of the methods S1-S2 described above may be performed. Alternatively, in other embodiments, the CPU may be configured to perform methods S1-S2 by any other suitable means (e.g., by means of firmware).
The functions described above herein may be performed, at least in part, by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), an Application Specific Standard Product (ASSP), a system on a chip (SOC), a load programmable logic device (CPLD), etc.
Program code for carrying out methods of the present invention may be written in any combination of one or more programming languages. These program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus such that the program code, when executed by the processor or controller, causes the functions/operations specified in the flowchart and/or block diagram to be implemented. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.
In the context of the present invention, a machine-readable medium may be a tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
While the invention has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.
Claims (10)
1. The direct-current micro-grid power control method is characterized by comprising the following steps of:
step S1, on the premise that line impedance influence is not ignored, a dynamic linearization model based on a distributed secondary control signal is established by utilizing input and output data of a micro-grid system, a nonlinear system is obtained through discretization, and an incremental DC micro-grid power control system model is obtained through equivalent data transformation;
and S2, constructing a model-free secondary control strategy based on the adaptive observer, estimating a secondary control signal, and distributing load power according to the rated capacity of the distributed power supply by combining a voltage-power droop control method based on the secondary control signal.
2. The method according to claim 1, wherein the dc micro-grid structure in the step S1 includes dc buses, distributed power sources, and loads, and each of the distributed power sources is connected to a common dc bus in a direct parallel manner.
3. The method for controlling power of a dc micro-grid according to claim 2, wherein the step S1 specifically includes:
step S11, a dynamic linearization model based on a secondary control signal is established by utilizing input and output data of a micro-grid system, and a mathematical expression is as follows:
y i (t)＝f(y i (t),n i (t))
wherein n is i (t) is a secondary control signal, and f (·) is an unknown system model parameter; y is i ＝[V oi ,P oi ] T For system output vector, V oi Is the output voltage of the ith distributed power supply, P oi Output power for the ith distributed power supply;
in an island operation mode, a distributed power supply in the micro-grid is responsible for maintaining system power balance and stable direct current bus voltage, and the power balance expression of the whole system is as follows:
wherein P is pcc Is the common load on the common DC bus, P linei N is the number of distributed power supplies, which is the power loss on the line impedance;
step S12, discretizing a dynamic linearization model based on the output voltage and the output power of the online measured distributed power supply to obtain a nonlinear system:
y i (k+1)＝f(y i (k),y i (k-1),…,y i (k-d),
n i (k),n i (k-1),…,n i (k-d))
wherein d represents an unknown positive integer of the system order;
step S13, based on nonlinear system assumption, converting nonlinear system partial format linearization equivalent into an incremental DC micro-grid power control system model, wherein the expression is as follows:
in phi, phi i (k)＝[Φ i1 (k),Φ i2 (k),…,Φ iL (k)] T Is a pseudo-jacobian matrix; Δy i Adding the system output vector; u (U) i (k)＝[n i (k),n i (k-1),…,n i (k-L+1)] T ，ΔU i For the corresponding vector increment, L is a dynamic linearization constant.
4. The method for controlling power of a dc micro-grid according to claim 3, wherein the nonlinear system assumption in the step S1 is specifically:
suppose 1: control function f (·) is related to control input n i (k) Is continuous;
suppose 2: the system being in the generalized Lipschitz, i.e. for any of the different moments k 1 、k 2 All satisfy:
||y i (k 1 +1)-y i (k 2 +1)||≤b||U i (k 1 )-U i (k 2 )||
where b is a normal number, L is a dynamic linearization constant, U i (k)＝[n i (k),n i (k-1),…,n i (k-L+1)] T ；
When hypothesis 1 and hypothesis 2 are true, if Δu i (k) There must be a pseudo jacobian matrix Φ with i not equal to 0 i (k) So that the nonlinear system is converted into:
in phi, phi i (k)＝[Φ i1 (k),Φ i2 (k),…,Φ iL (k)] T Is a pseudo-jacobian matrix.
5. The method for controlling power of a dc micro-grid according to claim 3, wherein the step S2 specifically includes:
step S21, constructing an adaptive observer to estimate a pseudo-Jacobian matrix phi (k), wherein the mathematical expression of the adaptive observer of the ith distributed power supply is as follows:
in the method, in the process of the invention,
is the output estimation error of the system; />
Is the system output estimated value; />
Is an estimate of the pseudo-jacobian matrix; k (K) i Is the observer gain matrix; Γ -shaped structure i (k)＝2(||ΔU i (k)||+μ i ) -1 ，μ i >0 is a weight factor for limiting the range of variation of the pseudo-jacobian matrix estimation value;
the output estimation error expression of the system is as follows:
in the method, in the process of the invention,
is the estimation error of the pseudo-jacobian matrix; f (F) i Satisfy F i ＝I-K i ，K i Is the observer gain matrix;
and S22, adopting a model-free secondary controller, and distributing load power according to the rated capacity of the distributed power supply by combining a voltage-power droop control method based on a secondary control signal.
6. The method according to claim 5, wherein the voltage-power droop control method based on the secondary control signal in step S22 specifically comprises: each converter is directly controlled by a droop function by adopting a distributed secondary control model, and a secondary control signal n is added to the droop function of the main control layer i Wherein the mathematical expression of the droop function is:
V oi ＝V ref -m i P oi +n i
wherein V is oi Is the output voltage of the ith distributed power source DG, V ref Is the rated voltage of a direct current bus, m i Is the droop coefficient of the ith distributed power supply, n i Is the secondary control signal of the ith distributed power supply.
7. The method according to claim 5, wherein the mathematical expression of the model-free secondary controller in step S22 is:
in the method, in the process of the invention,
for the desired output of the system, α > 0 is a weighting factor and δ is a finite normal number used to limit the rate of change of the control input.
8. A direct current micro grid power control system based on an adaptive observer, characterized in that the method according to any one of claims 1-7 is used, the system comprising:
the direct-current micro-grid power control model building module is used for building a direct-current micro-grid power control system model;
the self-adaptive observer is used for observing a coefficient matrix in the direct-current micro-grid power control system model;
the model-free secondary controller is used for carrying out model-free secondary control based on the coefficient matrix estimated value output by the adaptive observer and the observed data to obtain a secondary control signal;
the voltage-power droop control module is used for performing droop control according to a secondary control signal output by the model-free secondary controller to obtain load power distribution data of each distributed power supply;
and the direct-current micro-grid control module is used for controlling the power of the direct-current micro-grid according to the load power distribution data of each distributed power supply output by the voltage-power droop control module.
9. An electronic device comprising a memory and a processor, the memory having stored thereon a computer program, characterized in that the processor, when executing the program, implements the method according to any of claims 1-7.
10. A computer readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, implements the method according to any one of claims 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211511922.XA CN116054120A (en) | 2022-11-29 | 2022-11-29 | DC micro-grid power control method, system, equipment and storage medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211511922.XA CN116054120A (en) | 2022-11-29 | 2022-11-29 | DC micro-grid power control method, system, equipment and storage medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116054120A true CN116054120A (en) | 2023-05-02 |
Family
ID=86112262
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211511922.XA Pending CN116054120A (en) | 2022-11-29 | 2022-11-29 | DC micro-grid power control method, system, equipment and storage medium |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116054120A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116247734A (en) * | 2023-05-11 | 2023-06-09 | 南方电网数字电网研究院有限公司 | Distributed consistency power control method for edge-side weak communication environment |
-
2022
- 2022-11-29 CN CN202211511922.XA patent/CN116054120A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116247734A (en) * | 2023-05-11 | 2023-06-09 | 南方电网数字电网研究院有限公司 | Distributed consistency power control method for edge-side weak communication environment |
| CN116247734B (en) * | 2023-05-11 | 2024-03-12 | 南方电网数字电网研究院股份有限公司 | Distributed consistency power control method for edge-side weak communication environment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Panda | Multi-objective evolutionary algorithm for SSSC-based controller design | |
| Hooshmand et al. | Combination of AC transmission expansion planning and reactive power planning in the restructured power system | |
| Jazebi et al. | Reconfiguration of distribution networks to mitigate utilities power quality disturbances | |
| Chattopadhyay et al. | Reactive power planning incorporating voltage stability | |
| Kulkarni et al. | Improved droop control strategy for parallel connected power electronic converter based distributed generation sources in an Islanded Microgrid | |
| Marafão et al. | Decoupled reference generator for shunt active filters using the conservative power theory | |
| JP2009124913A (en) | Voltage imbalance elimination supporting device, supporting method, and program thereof | |
| CN114039353B (en) | Unified power flow acquisition method and device for hybrid power distribution network considering converter | |
| Wu et al. | Distributed optimal operation of hierarchically controlled microgrids | |
| CN108471109B (en) | Unified distributed control method and system for direct-current multi-microgrid system | |
| CN116054120A (en) | DC micro-grid power control method, system, equipment and storage medium | |
| Othman et al. | A coordinated real-time voltage control approach for increasing the penetration of distributed generation | |
| CN113890039B (en) | Multi-terminal flexible direct-current power distribution network power flow scheduling optimization method | |
| Abou Houran et al. | Active power filter module function to improve power quality conditions using GWO and PSO techniques for solar photovoltaic arrays and battery energy storage systems | |
| Gil-González et al. | A mixed-integer second-order cone model for optimal siting and sizing of dynamic reactive power compensators in distribution grids | |
| Taye et al. | A dynamic droop control for a DC microgrid to enhance voltage profile and proportional current sharing | |
| Cheng et al. | Distributed fixed-time secondary control for voltage restoration and economic dispatch of DC microgrids | |
| Kavithaa et al. | A prognostic energy optimization technique with unified power quality conditioner for energy stabilization in grid system | |
| Wong et al. | An optimal secondary multi-bus voltage and reactive power sharing control based on non-iterative decoupled linearized power flow for islanded microgrids | |
| CN111327040A (en) | Data-driven direct-current micro-grid power and voltage control method and device | |
| Grabowski et al. | Cost effective allocation and sizing of active power filters using genetic algorithms | |
| Wang et al. | Voltage instability performance of risk-based security constrained optimal power flow | |
| Mueller et al. | Generalized average modeling of DC subsystem in solid state transformers | |
| Xu et al. | Optimal distributed secondary control for an islanded microgrid | |
| Najafi et al. | Optimal capacitor placement and sizing in distribution networks |
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 |