Distributed power distribution control method and system capable of accurately constraining voltage operation boundaries

Abstract

The present invention discloses a distributed power distribution control method and system capable of accurately constraining voltage operation boundaries, and belongs to the field of distribution operation control; the distributed power distribution control method capable of accurately constraining voltage operation boundaries comprises: for droop-controlled distributed power sources with voltage support capability, a simplified voltage deviation control model based on droop-controlled distributed power sources in a distribution system is constructed through key process and parameter extraction; a symmetric state transition mapping function is designed in combination with the characteristics of a tangent transformation function, and the original control problem with upper and lower voltage limits is converted into an unconstrained continuous space for processing; based on the simplified voltage deviation control model, a distributed control algorithm based on sliding mode is designed on the basis of an unconstrained continuous space, so that the voltage can achieve coordinated control of multiple distributed power sources without exceeding the limit.

Description

Technical Field

[0001] The present invention belongs to the field of power distribution operation control, and in particular relates to a distributed power distribution control method and system that can accurately constrain voltage operation boundaries. Background Art

[0002] As the penetration rate of distributed power sources (such as solar power generation, wind power generation, etc.) in the power system continues to increase, the voltage control of the distribution system has become increasingly complex and critical. Traditional centralized voltage control methods often find it difficult to effectively deal with the voltage fluctuations and uncertainties brought by distributed power sources. Most of the existing distribution system voltage control strategies are based on simplified models or assumptions, and fail to fully consider the dynamic characteristics of distributed power sources and the coupling effects between them, resulting in poor control effects in practical applications, and may even cause safety issues such as voltage over-limit. In addition, traditional control methods often regard voltage control problems as constrained optimization problems, and the solution process is complex and computationally intensive, making it difficult to meet the real-time requirements for distribution system operation control. Therefore, there is an urgent need for a distributed distribution control method that can accurately constrain the voltage operation boundary. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a distributed power distribution control method and system that can accurately constrain voltage operating boundaries, thereby solving the problems in the prior art.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A distributed power distribution control method capable of accurately constraining voltage operation boundaries comprises the following steps:

[0006] For droop-controlled distributed power sources with voltage support capability, a simplified voltage deviation control model based on droop-controlled distributed power sources in the distribution system is constructed by extracting key processes and parameters;

[0007] Combining the characteristics of the tangent transformation function, a symmetric state transition mapping function is designed to transform the original control problem with voltage upper and lower limits into an unconstrained continuous space for processing;

[0008] Based on the simplified voltage deviation control model and unconstrained continuous space, a distributed control algorithm based on sliding mode is designed to achieve coordinated control of multiple distributed power sources without exceeding the voltage limit.

[0009] Furthermore, the dynamic model of the droop control distributed power supply is:

[0010]

[0011]

[0012] In the formula, , , , To droop control the nonlinear dynamic process inside the distributed power generation, The system state variables for droop control of distributed generation, yes The differential state of is the output variable of the system, is the input variable of the system, is the disturbance variable; and To droop the output frequency and voltage state of the distributed power supply, is the angular frequency state, and is the output active and reactive power after low-pass filtering; and are the frequency and voltage reference values ​​of the distributed power supply, Represent the droop control distributed power supply output voltage and output current of d Axis and q Axis component, and To control the grid connection point voltage of distributed generation for droop of d Axis and q Axis component, and To droop the distributed generation output line current of d Axis and q Axis component, The rated frequency at which the power distribution system operates.

[0013] Furthermore, the simplified voltage deviation control model is:

[0014]

[0015] In the formula, the subscript i Indicates that this power supply is the first i A controllable power source connected to a distributed control network, Indicates voltage deviation, for The differential state of is the intermediate state defined, yes The differential state of is the voltage output value, is the voltage input reference value, is the voltage reference value, is the input gain, Nonlinear processes inside a power supply.

[0016] Furthermore, the symmetric state conversion mapping function is:

[0017]

[0018] In the formula, yes The maximum boundary value of This is the state after voltage deviation mapping.

[0019] Furthermore, the sliding mode-based distributed control algorithm is expressed as:

[0020]

[0021] In the formula, is the sliding surface; is a nonlinear function defined as Indicates its differential state; , and are all positive integers, A positive number less than 1.

[0022] Furthermore, the sliding surface The calculation formula is:

[0023] ,

[0024]

[0025] In the formula, is the tracking error between distributed power sources, yes The differential state of N is the number of distributed generation in the system and satisfies , and is the element in the communication matrix, For the j The output state quantity of a distributed power source.

[0026] Distributed power distribution control system that can accurately constrain voltage operating boundaries, including:

[0027] Model building module: For droop-controlled distributed power sources with voltage support capability, a simplified voltage deviation control model based on droop-controlled distributed power sources in the distribution system is constructed through key process and parameter extraction;

[0028] State mapping module: Based on the characteristics of the tangent transformation function, a symmetric state conversion mapping function is designed to transform the original control problem with voltage upper and lower limits into an unconstrained continuous space for processing;

[0029] And, control module: Based on the simplified voltage deviation control model, on the basis of unconstrained continuous space, a distributed control algorithm based on sliding mode is designed to achieve coordinated control of multiple distributed power sources without exceeding the voltage limit.

[0030] A computer storage medium stores a readable program, which, when running, can execute the above-mentioned distributed power distribution control method that can accurately constrain voltage operating boundaries.

[0031] An electronic device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0032] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the above-mentioned distributed power distribution control method that can accurately constrain voltage operation boundaries.

[0033] A computer program product includes computer instructions, wherein the computer instructions instruct a computing device to execute operations corresponding to the above-mentioned distributed power distribution control method that can accurately constrain voltage operating boundaries.

[0034] Beneficial effects of the present invention:

[0035] 1. The present invention can more accurately describe the voltage control characteristics of the distributed power supply by constructing a simplified voltage control model and a symmetrical state transition mapping function, thereby improving the accuracy of voltage control.

[0036] 2. The distributed voltage dynamic control algorithm based on sliding mode of the present invention can realize the coordinated control of multiple distributed power sources, adjust the control strategy in real time according to the system operation status, and enhance the flexibility of voltage control.

[0037] 3. The present invention converts the constrained voltage control problem into an unconstrained continuous space through space mapping technology, which simplifies the solution process of the control problem, reduces the computational complexity, and improves the real-time performance of the control algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 is a schematic diagram of a distributed control architecture of a power distribution system provided by the present invention;

[0040] Figure 2 The present invention is a distributed power distribution control flow chart that can accurately constrain voltage operation boundaries;

[0041] Figure 3 It is a simulation system diagram of the power distribution system for testing of the present invention;

[0042] Figure 4 This is the result of the distributed control operation of the present invention which can accurately constrain the voltage. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Example 1

[0045] like Figure 1 As shown, it is the overall application scenario of the control method of the present invention. In the power distribution system in the figure, N distributed power sources with droop control are connected. They are driven by their own controllers, and the controllers are interconnected through a distributed communication network. Since the distributed power supply is connected to the power grid through power electronic equipment, when power disturbance problems such as load switching occur in the system, the power distribution system is prone to rapid voltage fluctuations and over-limit problems, thereby endangering the safe and stable execution of the system. This practical problem will be solved by the control method of the present invention.

[0046] like Figure 2 As shown, a distributed power distribution control method that can accurately constrain voltage operation boundaries includes the following steps:

[0047] S1, for droop-controlled distributed power sources with voltage support capability, a simplified voltage deviation control model based on droop-controlled distributed power sources in the distribution system is constructed through key process and parameter extraction;

[0048] The droop-controlled distributed power source simulates the droop characteristics of the synchronous motor, so it can achieve voltage support and recovery for the distribution system. The present invention models the droop-controlled distributed power source and then simplifies the design so that it meets the distributed control design requirements of the distribution system.

[0049] By analyzing the dynamic control process of the distributed power source with droop control, especially the internal current and voltage double loops, the power outer loop, and the droop process, a complete dynamic model of the distributed power source with droop control in the following distribution system can be constructed:

[0050] (1.1)

[0051] In the formula, , , , To droop control the nonlinear dynamic process inside the distributed power generation, The system state variables for droop control of distributed generation, yes The differential state of is the output variable of the system, is the input variable of the system, are disturbance variables; they are expressed as:

[0052] (1.2)

[0053] in, and To droop the output frequency and voltage state of the distributed power supply, is the angular frequency state, and is the output active and reactive power after low-pass filtering; and are the frequency and voltage reference values ​​of the distributed power supply, Represent the droop control distributed power supply output voltage and output current of d Axis and q Axis component, and To control the grid connection point voltage of distributed generation for droop of d Axis and q Axis component, and To droop the distributed generation output line current of d Axis and q Axis component, The rated frequency at which the power distribution system operates.

[0054] By extracting the key processes and key parameters of the voltage control process, a simplified voltage deviation control model based on droop control of distributed power sources in the distribution system can be constructed;

[0055] (1.3)

[0056] In the formula, the subscript i Indicates that this power supply is the first i A controllable power source connected to a distributed control network, Indicates voltage deviation, for The differential state of yes The differential state of is the voltage output value, is the voltage input reference value, is the voltage reference value, is the input gain, Nonlinear processes inside a power supply.

[0057] S2, combining the characteristics of the tangent transformation function, designs a symmetric state transition mapping function to transform the original control problem with voltage upper and lower limits into an unconstrained continuous space for processing;

[0058] Using the tangent transformation function for one cycle The symmetrical state conversion mapping function that constrains the upper and lower limits of voltage operation can be designed as follows:

[0059] (1.4)

[0060] In the formula, yes The maximum boundary value of This is the state after voltage deviation mapping.

[0061] The mapped state can be expressed as:

[0062] (1.5)

[0063] The above mapping results show that when Approaching the border When the voltage deviation state after conversion is will tend to infinity. Therefore, if can be bounded by finite values, then Under the condition of , it can always ensure that the voltage deviation does not exceed the set maximum operating limit, that is ,when hour.

[0064] The time derivative of the mapping function is:

[0065] (1.6)

[0066] To facilitate calculation, a nonlinear function is defined , expressed as , and it is easy to derive .

[0067] S3, based on the simplified voltage deviation control model, on the basis of unconstrained continuous space, design a distributed control algorithm based on sliding mode, so that the voltage can quickly and smoothly achieve coordinated control of multiple distributed power sources without exceeding the limit;

[0068] Based on the distributed control requirements, the tracking error between distributed power sources is defined as follows:

[0069] (1.7)

[0070] In the formula, is the tracking error between distributed power sources, N is the number of distributed generation in the system, and For the elements in the communication matrix, when the power i and power supply j When data is being transmitted, ,otherwise , when distributed power i When a global reference is available, ,otherwise ; For the j The output state quantity of a distributed power source.

[0071] Then, based on the defined tracking error filling, the sliding surface is further defined for:

[0072] (1.8)

[0073] In the formula, yes The differential state of , is a positive integer.

[0074] Based on the above tracking error and sliding surface state, a distributed control algorithm based on sliding mode described in the present invention can be designed as follows:

[0075] (1.9)

[0076] In the formula, Indicates its differential state; and are all positive integers, A positive number less than 1.

[0077] In summary, if the initial value of the distributed power supply voltage in the distribution system is can be guaranteed, then the output voltage of the distributed power supply can always be maintained within the given maximum range during the coordination process. .

[0078] The global asymptotic stability of the system is proved using Lyapunov stability theory, and the performance of the control method is comprehensively evaluated through simulation experiments.

[0079] To prove the stability, the error and sliding surface in global vector form can be expressed as:

[0080] (1.10)

[0081] In the formula, the error vector in global form is Expressed as , the state vector Expressed as , sliding surface vector Expressed as , is the Laplace matrix of the distributed control system, expressed as ,in is the internal state of the matrix, expressed as as well as .

[0082] Furthermore, a proof model based on Lyapunov stability theory is designed as follows:

[0083] (1.11)

[0084] Its derivative along the sliding surface can be expressed as:

[0085] (1.12)

[0086] In the formula, is a defined matrix quantity, expressed as

[0087] In summary, we can draw the conclusion and , proving the stability of the control algorithm. In addition, the design of the sliding surface can also ensure that the control method can achieve stable voltage recovery.

[0088] Based on similar inventive concepts, an embodiment of the present invention further provides a computer storage medium storing a readable program, which, when executed, can execute the above-mentioned distributed power distribution control method capable of accurately constraining voltage operating boundaries.

[0089] Based on similar inventive concepts, an embodiment of the present invention provides an electronic device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0090] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the above-mentioned distributed power distribution control method that can accurately constrain voltage operation boundaries.

[0091] Based on similar inventive concepts, an embodiment of the present invention further provides a computer program product, including computer instructions, which instruct a computing device to execute operations corresponding to the above-mentioned distributed power distribution control method that can accurately constrain voltage operating boundaries.

[0092] Example 2

[0093] like Figure 3 As shown, the simulation test scenario provided in this embodiment is a multi-node microgrid system, in which 4 droop-controlled distributed power sources and 4 uncontrolled photovoltaic systems (PV) are connected. In addition, 3 loads are connected to the system, load #1 (5kW, 5kVar), load #2 (5kW, 5kVar) and load #3 (15kW, 15kVar). In order to complete the performance test. In this test environment, the operating boundary of the voltage is set to (0.95pu, 1.05pu).

[0094] Figure 4 The simulation test results show the microgrid operation test status from 5:00 to 11:00. Figure 4 In (a), the output data of the four photovoltaics are the actual photovoltaic outputs of the real system. Figure 4 In (b), the results show the output voltage of the four distributed power sources when the photovoltaic power changes greatly. It can be observed from the results that when the photovoltaic power fluctuates greatly, the method provided by the present invention can always maintain the output voltage of the distributed power source within the given constraint boundary, and there is no short-term voltage over-limit safety operation problem.

[0095] Example 3

[0096] In this embodiment, a distributed power distribution control system that can accurately constrain voltage operation boundaries is proposed, including:

[0097] Model building module: For droop-controlled distributed power sources with voltage support capability, a simplified voltage deviation control model based on droop-controlled distributed power sources in the distribution system is constructed through key process and parameter extraction;

[0098] State mapping module: Based on the characteristics of the tangent transformation function, a symmetric state conversion mapping function is designed to transform the original control problem with voltage upper and lower limits into an unconstrained continuous space for processing;

[0099] And, control module: Based on the simplified voltage deviation control model, on the basis of unconstrained continuous space, a distributed control algorithm based on sliding mode is designed to achieve coordinated control of multiple distributed power sources without exceeding the voltage limit.

[0100] The method of the present invention may be implemented in hardware, firmware, or as software or computer code that may be stored in a recording medium (such as a CDROM, RAM, floppy disk, hard disk, or magneto-optical disk), or as computer code that is originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded over a network and will be stored in a local recording medium, so that the method described herein may be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It is understood that a computer, processor, microprocessor controller, or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, processor, or hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the method shown herein.

[0101] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A distributed power distribution control method capable of accurately constraining voltage operation boundaries, characterized in that: The following steps are involved: For droop-controlled distributed power sources with voltage support capability, a simplified voltage deviation control model based on droop-controlled distributed power sources in the distribution system is constructed by extracting key processes and parameters; Combining the characteristics of the tangent transformation function, a symmetric state transition mapping function is designed to transform the original control problem with voltage upper and lower limits into an unconstrained continuous space for processing; Based on the simplified voltage deviation control model, a distributed control algorithm based on sliding mode is designed on the basis of unconstrained continuous space, so that the voltage can achieve coordinated control of multiple distributed power sources without exceeding the limit. The simplified voltage deviation control model is: In the formula, the subscript i Indicates that this power supply is the first i A controllable power source connected to a distributed control network, Indicates voltage deviation, for The differential state of is the intermediate state defined, yes The differential state of is the voltage output value, is the voltage input reference value, is the voltage reference value, is the input gain, Nonlinear processes inside a power supply.

2. The distributed power distribution control method capable of accurately constraining voltage operation boundaries according to claim 1 is characterized in that: The dynamic model of the droop control distributed power supply is: In the formula, , , , To droop control the nonlinear dynamic process inside the distributed power generation, The system state variables for droop control of distributed generation, yes The differential state of is the output variable of the system, is the input variable of the system, is the disturbance variable; and To droop the output frequency and voltage state of the distributed power supply, is the angular frequency state, and is the output active and reactive power after low-pass filtering; and are the frequency and voltage reference values ​​of the distributed power supply, Represent the droop control distributed power supply output voltage and output current of d Axis and q Axis component, and To control the grid connection point voltage of distributed generation for droop of d Axis and q Axis component, and To droop the distributed generation output line current of d Axis and q Axis component, The rated frequency at which the power distribution system operates.

3. The distributed power distribution control method capable of accurately constraining voltage operation boundaries according to claim 2 is characterized in that: The symmetric state conversion mapping function is: In the formula, yes The maximum boundary value of This is the state after voltage deviation mapping.

4. The distributed power distribution control method capable of accurately constraining voltage operation boundaries according to claim 3 is characterized in that: The distributed control algorithm based on sliding mode is expressed as: In the formula, is the sliding surface; is a nonlinear function defined as Indicates its differential state; , and are all positive integers, A positive number less than 1.

5. The distributed power distribution control method capable of accurately constraining voltage operation boundaries according to claim 4 is characterized in that: The sliding surface The calculation formula is: ， In the formula, is the tracking error between distributed power sources, yes The differential state of N is the number of distributed generation in the system and satisfies , and is the element in the communication matrix, For the j The output state quantity of a distributed power source.

6. A distributed power distribution control system that can accurately constrain voltage operating boundaries, characterized in that: include: Model building module: For droop-controlled distributed power sources with voltage support capability, a simplified voltage deviation control model based on droop-controlled distributed power sources in the distribution system is constructed through key process and parameter extraction; State mapping module: Based on the characteristics of the tangent transformation function, a symmetric state conversion mapping function is designed to transform the original control problem with voltage upper and lower limits into an unconstrained continuous space for processing; And, control module: Based on the simplified voltage deviation control model, a distributed control algorithm based on sliding mode is designed on the basis of unconstrained continuous space, so that the voltage can achieve coordinated control of multiple distributed power sources without exceeding the limit; The simplified voltage deviation control model is: In the formula, the subscript i Indicates that this power supply is the first i A controllable power source connected to a distributed control network, Indicates voltage deviation, for The differential state of is the intermediate state defined, yes The differential state of is the voltage output value, is the voltage input reference value, is the voltage reference value, is the input gain, Nonlinear processes inside a power supply.

7. A computer storage medium storing a readable program, characterized in that: When the program is running, it can execute the distributed power distribution control method capable of accurately constraining the voltage operating boundary as described in any one of claims 1 to 5.

8. An electronic device, characterized in that: include: A processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the distributed power distribution control method that can accurately constrain voltage operating boundaries as described in any one of claims 1-5.

9. A computer program product comprising computer instructions, characterized in that The computer instructions instruct the computing device to execute operations corresponding to the distributed power distribution control method that can accurately constrain voltage operating boundaries as described in any one of claims 1-5.

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