Islanded microgrid distributed adaptive frequency modulation method and system thereof

Abstract

This invention discloses a distributed adaptive frequency regulation method for isolated microgrids. The method is executed collaboratively by each distributed power generation unit. First, it monitors the system frequency and its own status in real time to determine frequency regulation needs, and dynamically activates or suspends its frequency regulation participation status through an event-triggered mechanism. The activated frequency regulation participating units calculate dynamic weighting coefficients based on the frequency deviation direction, combined with equipment type, power generation stability, reserve power utilization rate, and operating costs. Then, it exchanges information with neighboring units through a sparse communication network, runs an adaptive distributed consensus algorithm based on the dynamic weights, and generates frequency recovery and power allocation control signals. After integration, a reference frequency correction is obtained, and the traditional droop control is corrected in real time to adjust the unit output. This invention can achieve dynamic adaptive allocation of frequency regulation priorities, reduce communication burden, quickly restore system frequency, and improve the stability and economy of isolated microgrid operation.

Description

Technical Field

[0001] This invention relates to the field of microgrid operation and control technology, specifically to a distributed adaptive frequency regulation method and system for islanded microgrids. Background Technology

[0002] Islanded microgrids, as key power systems integrating distributed renewable energy and energy storage devices, are widely used in remote islands, mountainous areas, and other scenarios without large power grid coverage. Their frequency stability directly determines the reliability of power supply. However, islanded microgrids have low inertia and weak damping, and renewable energy generation such as wind and solar power is intermittent and uncertain, which can easily lead to an imbalance between power generation and consumption, resulting in large frequency fluctuations and seriously threatening equipment safety and power supply continuity. Therefore, an efficient coordinated frequency regulation mechanism is urgently needed to ensure the stable operation of the system.

[0003] To address this need, isolated microgrids typically employ a hierarchical architecture for frequency control. Primary frequency regulation achieves coarse power allocation through local droop control, while secondary frequency regulation specifically eliminates frequency deviations and restores rated values. However, existing secondary frequency regulation schemes still have significant limitations: centralized systems rely on a central controller and high-speed communication networks, which not only poses a single point of failure risk but also suffers from poor scalability; while conventional distributed collaborative frequency regulation can eliminate dependence on a central node, it fails to fully consider the fundamental differences in frequency regulation capabilities, costs, and operational constraints among heterogeneous devices such as wind, solar, and energy storage, lacks a flexible adaptive mechanism for power regulation priorities, and cannot dynamically allocate power output based on equipment status and frequency regulation requirements; furthermore, it often employs periodic communication modes, making it difficult to achieve a balance between system response speed and communication burden. Ultimately, this leads to problems such as low frequency regulation efficiency and energy waste, failing to meet the requirements for safe and economical operation of isolated microgrids. Summary of the Invention

[0004] This invention proposes a distributed adaptive frequency modulation method and system for isolated microgrids to address the shortcomings of existing technologies, such as the inability of isolated microgrid frequency control to dynamically allocate output priorities based on equipment status and frequency modulation requirements, and the difficulty in balancing response speed and communication burden in periodic communication modes. This invention achieves dynamic adaptive allocation of frequency modulation priorities for each distributed power unit, rapid recovery of system frequency, and optimized utilization of communication resources.

[0005] This invention provides a distributed adaptive frequency regulation method for isolated microgrids, the method being executed collaboratively by multiple distributed power supply units, including:

[0006] Step S1: Monitor the frequency deviation of the isolated microgrid, the output power change rate of each distributed power unit, and the state of charge of the energy storage device in real time. When at least one of the frequency deviation, power change rate, or state of charge exceeds the corresponding dynamic adjustable trigger threshold, trigger the corresponding distributed power unit as a frequency modulation participation unit; otherwise, keep the frequency modulation dormant state.

[0007] Step S2: Determine the power adjustment direction based on the direction of the frequency deviation. The frequency modulation participation unit calculates a dynamic weighting coefficient for allocating power output priority based on its own equipment type, operating status parameters and the power adjustment direction.

[0008] In step S3, the frequency modulation participating unit exchanges its own frequency and power state information with adjacent frequency modulation participating units through a sparse communication network, and generates frequency recovery control input signal and power allocation control input signal based on the dynamic weight coefficient calculated in step S2 through an adaptive distributed consensus algorithm.

[0009] In step S4, the frequency modulation participation unit superimposes and integrates the frequency recovery control input signal and the power distribution control input signal generated in step S3 to generate a correction amount for the reference frequency.

[0010] Step S5: Input the correction amount of the reference frequency to the local active power-frequency droop controller, adjust the output power of the frequency modulation participating unit, so that the frequency of the islanded microgrid is restored to the rated value, and the output ratio of each frequency modulation participating unit is allocated according to the dynamic weighting coefficient.

[0011] Preferably, in step S1, when the frequency deviation and the power change rate exceed the corresponding dynamic adjustable trigger threshold, the dynamic adjustable trigger threshold is dynamically adjusted according to the absolute values ​​of the frequency deviation change rate and the power change rate: when the absolute values ​​of the frequency deviation change rate and the power change rate increase, the corresponding dynamic adjustable trigger threshold is lowered; when the absolute values ​​of the frequency deviation change rate and the power change rate decrease, the corresponding dynamic adjustable trigger threshold is raised.

[0012] Preferably, when the state of charge exceeds the preset safe operating range, the energy storage device is triggered to participate in or withdraw from frequency regulation.

[0013] Preferably, the adjustment strategy for the dynamically adjustable trigger threshold is as follows: when the system state variables change rapidly, the trigger threshold is lowered to accelerate the coordinated frequency modulation response; when the system state variables change gradually, the trigger threshold is raised to reach a steady-state reference value to reduce communication; specific calculations are as follows:

[0014]

[0015]

[0016] in, This is the reference threshold under steady-state frequency conditions; This is the reference threshold under steady-state power conditions; This is the frequency adjustment factor; This is the power adjustment coefficient; This is the minimum threshold lower limit for frequency. This is the lower limit of the minimum threshold for power.

[0017] Preferably, the adaptive allocation rule for the dynamic weight coefficients in step S2 is as follows:

[0018] When the frequency deviation is negative, new energy equipment will increase its output first, and energy storage equipment will serve as a backup. The output of new energy equipment will be allocated according to the backup power utilization rate, power generation stability and power generation cost, and the output of energy storage equipment will be allocated according to the backup power utilization rate and power generation stability.

[0019] When the frequency deviation is positive, the energy storage device prioritizes charging and absorbing power, while the new energy device serves as a backup. The energy storage devices allocate charging power according to the SOC. When the frequency cannot be restored by energy storage alone, the new energy devices work together to reduce power output and allocate the power reduction according to the cost of curtailment.

[0020] when At this time, the unit Weighting coefficients The calculation formula is:

[0021]

[0022] in, Gain coefficients calculated for weights; For unit The coefficient for normalized power generation cost; For unit The baseline weights; For unit The normalized power generation stability coefficient; For unit exist The available reserve power at any given time is defined as the difference between the equipment's current maximum generating power and its current output, calculated using the following formula: ; Indicates the rated standby power; It is a pre-defined, extremely small positive number; This is for frequency deviation;

[0023] when At this time, the unit Weighting coefficients The calculation formula is:

[0024]

[0025] in, Gain coefficients calculated for weights; For unit The baseline weights; For unit The normalized curtailment cost coefficient; For unit exist The state of charge at any given time; when the unit When it is a new energy equipment unit, The value is 0.5.

[0026] Preferably, in step S3, the adaptive distributed consensus algorithm is a unit participating in frequency modulation. Generated frequency recovery control input and power distribution control input Superimposed to generate total control input The adaptive distributed consensus formula is:

[0027]

[0028]

[0029]

[0030] in, To be with unit Adjacent unit sets; These are elements of the communication adjacency matrix; For unit exist Angular frequency at time; For unit exist Angular frequency at time; The weight coefficient for the leadership node; The rated value for the frequency modulation participating unit; For unit exist Active power at any given moment; For unit exist Active power at any given moment; for Consistency control gain; for Consistency control gain; For application to the unit The result of the dynamic weighting function; For application to the unit The result of the dynamic weighting function.

[0031] Preferably, in step S4, the function of the integrator is to integrate the sum of the control inputs to generate the reference frequency correction. for:

[0032]

[0033] The integral stage continues to operate until the system frequency recovers to the rated value. Furthermore, each frequency modulation participating unit participates in power allocation according to a dynamic weighting coefficient.

[0034] This invention also provides a control system for a distributed adaptive frequency modulation method for isolated microgrids, comprising:

[0035] The status monitoring and judgment module is used to monitor the frequency deviation of the islanded microgrid, the output power change rate of each distributed power unit, and the state of charge of the energy storage device in real time. When at least one of the frequency deviation, power change rate, or state of charge exceeds the corresponding dynamic adjustable trigger threshold, the corresponding distributed power unit is triggered as a frequency modulation participation unit; otherwise, the frequency modulation dormancy state is maintained.

[0036] The weight calculation module is used to determine the power adjustment direction based on the direction of the frequency deviation. The frequency modulation participation unit calculates the dynamic weight coefficient for allocating output priority based on its own equipment type, operating status parameters and the power adjustment direction.

[0037] The consensus control module is used for the frequency modulation participating unit to exchange its own frequency and power state information with adjacent frequency modulation participating units through a sparse communication network, and to generate frequency recovery control input signal and power allocation control input signal based on the dynamic weight coefficient calculated in step S2 through an adaptive distributed consensus algorithm.

[0038] The integral adjustment module, wherein the frequency modulation participation unit superimposes and integrates the frequency recovery control input signal and the power distribution control input signal generated in step S3 to generate a correction amount for the reference frequency;

[0039] The power allocation execution module inputs the correction amount of the reference frequency to the local active power-frequency droop controller, adjusts the output power of the frequency modulation participating unit, restores the frequency of the islanded microgrid to the rated value, and allocates the output ratio of each frequency modulation participating unit according to the dynamic weighting coefficient.

[0040] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of any of the above-described distributed adaptive frequency modulation methods for islanded microgrids.

[0041] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the above-described distributed adaptive frequency modulation methods for isolated microgrids.

[0042] This invention proposes a distributed adaptive frequency regulation method for isolated microgrids. By introducing adjustable dynamic weight coefficients, the output weight of each distributed power unit can be dynamically adjusted according to the direction of frequency change, equipment type, power generation stability, reserve power utilization rate, and operating cost, thereby achieving adaptive allocation of power regulation priority. Furthermore, an event triggering mechanism based on frequency deviation, power change, and energy storage state of charge (SOC) is designed. By dynamically adjusting the trigger threshold, the frequency regulation participation status of each unit can be flexibly controlled, effectively reducing the communication burden while ensuring rapid system response. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the distributed adaptive frequency modulation method for isolated microgrids provided by the present invention;

[0045] Figure 2 This is the overall control framework diagram for the operation of the islanded microgrid distributed adaptive frequency regulation system provided by the present invention;

[0046] Figure 3 This is a control architecture diagram based on a distributed consensus algorithm in the distributed adaptive frequency regulation method for isolated microgrids provided by this invention;

[0047] Figure 4 This is a flowchart of the dynamic weight coefficient adaptive adjustment process in the distributed adaptive frequency modulation method for isolated microgrids provided by this invention;

[0048] Figure 5 This is a flowchart of the event triggering mechanism in the distributed adaptive frequency modulation method for isolated microgrids provided by this invention;

[0049] Figure 6 This is a schematic diagram of the module of the islanded microgrid distributed adaptive frequency modulation system provided by the present invention;

[0050] Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0052] Combination Figure 1 This invention describes a distributed adaptive frequency regulation method for isolated microgrids, wherein the method is executed collaboratively by multiple distributed power supply units, including:

[0053] Step S1: Monitor the frequency deviation of the isolated microgrid, the output power change rate of each distributed power unit, and the state of charge of the energy storage device in real time. When at least one of the frequency deviation, power change rate, or state of charge exceeds the corresponding dynamic adjustable trigger threshold, trigger the corresponding distributed power unit as a frequency modulation participation unit; otherwise, keep the frequency modulation dormant state.

[0054] Step S2: Determine the power adjustment direction based on the direction of the frequency deviation. The frequency modulation participation unit calculates a dynamic weighting coefficient for allocating power output priority based on its own equipment type, operating status parameters and the power adjustment direction.

[0055] In step S3, the frequency modulation participating unit exchanges its own frequency and power state information with adjacent frequency modulation participating units through a sparse communication network, and generates frequency recovery control input signal and power allocation control input signal based on the dynamic weight coefficient calculated in step S2 through an adaptive distributed consensus algorithm.

[0056] In step S4, the frequency modulation participation unit superimposes and integrates the frequency recovery control input signal and the power distribution control input signal generated in step S3 to generate a correction amount for the reference frequency.

[0057] Step S5: Input the correction amount of the reference frequency to the local active power-frequency droop controller, adjust the output power of the frequency modulation participating unit, so that the frequency of the islanded microgrid is restored to the rated value, and the output ratio of each frequency modulation participating unit is allocated according to the dynamic weighting coefficient.

[0058] Furthermore, in step S1, when the frequency deviation and the power change rate exceed the corresponding dynamic adjustable trigger threshold, the dynamic adjustable trigger threshold is dynamically adjusted according to the absolute values ​​of the system frequency deviation change rate and the power change rate: when the change rate increases, the corresponding dynamic adjustable trigger threshold is lowered; when the change rate decreases, the corresponding dynamic adjustable trigger threshold is raised.

[0059] Combination Figure 2 This invention describes the overall control framework for the operation of an islanded microgrid distributed adaptive frequency regulation system. The system comprises multiple distributed power generation units, including renewable energy sources and energy storage devices with frequency regulation potential. All power generation units are connected to the load via a common AC bus. Each distributed power generation unit is equipped with a local status monitoring module, an event triggering module, and a secondary frequency regulation controller. The secondary frequency regulation controller includes a weight calculation module, a consistency control module, and an integral adjustment module. It achieves status information exchange between adjacent units through a sparse communication network, eliminating the need for a central controller and supporting plug-and-play functionality.

[0060] For distributed power sources with frequency regulation potential in the system, droop control is used for local primary frequency regulation. Based on this, under the distributed cooperative control framework, combined with multi-agent consensus theory, an adaptive distributed consensus algorithm is designed and embedded into the secondary frequency regulation controller to form multiple distributed adaptive frequency regulation units. When the frequency of the independent microgrid fluctuates, the frequency regulation unit status and frequency regulation requirements can be used for priority adaptive secondary frequency control.

[0061] Combination Figure 3 The control architecture based on a distributed consensus algorithm in the distributed adaptive frequency regulation method for isolated microgrids of the present invention is described, wherein the distributed frequency control architecture is applied to each distributed power unit. The local frequency-power droop characteristic is expressed as:

[0062]

[0063] in, Distributed power supply unit exist The actual output angular frequency at that moment; For unit exist The reference angular frequency at that moment; For unit Active power-frequency droop factor; For unit exist The active power output at any given time.

[0064] Since frequency recovery cannot be achieved solely through droop control, this invention adds a secondary frequency modulation controller to the frequency modulation unit, embedding an adaptive distributed consensus algorithm within it to correct the frequency deviation in traditional droop control until frequency recovery is achieved, i.e., adding a correction amount to the rated frequency. :

[0065]

[0066] Therefore, the specific design of the adaptive distributed consensus algorithm is as follows:

[0067] First, based on the concept of consistency control:

[0068]

[0069] Differentiating the improved droop control formula yields:

[0070]

[0071] Define auxiliary control input variables:

[0072] , ,

[0073] Therefore, the actual frequency deviation correction input to the droop control can be expressed as:

[0074]

[0075] For each unit Design frequency recovery control inputs separately and power distribution control input ,for:

[0076]

[0077]

[0078] in, To be with unit Adjacent unit sets; For elements of the communication adjacency matrix, if the cell and unit If there is a communication link between them, then ,otherwise ; and Units and exist Angular frequency at time; For a given unit in the network that is selected as the leader node, the weight coefficient is used. For other follower nodes, ;this This ensures that the system frequency can be restored to the rated value. . and Units and exist Active power at any given moment; and To ensure consistent gain control, the goal is to make the frequency and power orders of magnitude higher. and It is the same dynamic weight function Applied to different units ( and The result after that.

[0079] In summary, the control input of each frequency modulation participating unit is based on the proposed adaptive distributed consensus algorithm. Represented as:

[0080]

[0081] In subsequent steps, the integrator integrates the sum of the control inputs to generate the reference frequency correction. for:

[0082]

[0083] The integral stage continues to operate until the system frequency recovers to the rated value. Furthermore, each frequency modulation participating unit participates in power allocation according to a dynamic weighting coefficient.

[0084] Combination Figure 4 The present invention describes the adaptive adjustment of dynamic weighting coefficients in the distributed adaptive frequency regulation method for isolated microgrids. These dynamic weighting coefficients can be adaptively adjusted according to the direction of frequency change, device type, and operating status to achieve the following power priority allocation:

[0085] When the frequency decreases, renewable energy equipment is prioritized to increase output, with energy storage equipment serving as a backup. The participation level among different renewable energy equipment is allocated based on the availability of their backup power, power generation stability, and power generation cost. When the frequency increases, energy storage equipment is prioritized to charge and absorb power, while renewable energy equipment serves as a backup. The participation level among different energy storage equipment is allocated based on their state of charge. When energy storage alone cannot restore the frequency, renewable energy equipment will work together to reduce its output to achieve frequency restoration. The participation level among different renewable energy entities is allocated based on the cost of curtailment.

[0086] The process of calculating dynamic weighting coefficients is as follows: Figure 4 As shown, the details are as follows:

[0087] First, the system frequency is obtained through the status monitoring module to determine the frequency deviation. The direction of the force determines whether the system needs to increase or decrease its output.

[0088] When the frequency deviation is negative, the output needs to be increased. New energy equipment should increase its output first, and energy storage equipment should be used as a backup. The output of new energy equipment should be allocated according to the backup power utilization rate, power generation stability and power generation cost. The output of energy storage equipment should be allocated according to the backup power utilization rate and power generation stability.

[0089] When the frequency deviation is positive, the output needs to be reduced. The energy storage equipment is charged and absorbs power first, while the new energy equipment is used as a backup. The charging power is allocated among the energy storage equipment according to the SOC. When the frequency cannot be restored by energy storage alone, the new energy equipment reduces the output in coordination and the reduction power is allocated according to the cost of curtailment.

[0090] Secondly, through the indicator factors of new energy equipment and energy storage device indicator factors Distinguish between equipment types: When equipment When it comes to new energy equipment (wind turbines, photovoltaics), , When the equipment When used as an energy storage device, , This provides the baseline weights for new energy and energy storage devices. The calculation formula is:

[0091]

[0092] in, , These are preset benchmark values ​​for the types of new energy equipment and energy storage equipment, respectively, and their values ​​are determined based on frequency deviation. The direction setting is used to establish global priority:

[0093] when When increased output is required, set ;

[0094] when When it is necessary to reduce output, set ;

[0095] Next, normalized cost coefficients need to be preset for different types of equipment for output allocation within each type: when output needs to be increased, equipment with higher generation costs has a lower weight; when output needs to be reduced, equipment with higher curtailment costs has a lower weight. The specific preset ranges are as follows:

[0096] Normalized generation cost coefficient Preset: When When the unit is a new energy device, The value approaches 0; when When the unit is an energy storage device, The value approaches 1;

[0097] Normalized curtailment cost coefficient Preset: When When the unit is a new energy device, The value is determined based on the cost of power curtailment, with higher costs approaching 1 and lower costs approaching 0.5. The lower limit is not set to 0 to avoid excessively high weighting of new energy equipment, which could disregard the requirement that energy storage devices should be prioritized for power absorption, while new energy equipment serves as a backup. When the unit is an energy storage device, The value approaches 0.

[0098] When the system needs to increase its output, the dynamic weighting coefficient of power allocation is also related to the power generation stability coefficient. This is related to prioritizing the use of highly stable equipment in frequency regulation, avoiding frequency fluctuations caused by unstable equipment such as low-wind-speed wind turbines and photovoltaic systems operating under weak sunlight. Specifically, the method should be determined based on the equipment type and normalized to the [0,1] interval.

[0099] When the device is an energy storage device:

[0100]

[0101] This formula indicates that the stability of the energy storage device is best when its state of charge is maintained at 0.5.

[0102] When the equipment is a fan:

[0103]

[0104] in, Real-time wind speed; Rated wind speed; , These are the inlet wind speed and outlet wind speed of the fan, respectively.

[0105] When the equipment is a photovoltaic device:

[0106]

[0107] in, Real-time light intensity; The threshold of light intensity at which photovoltaic equipment begins to generate electricity. This is the standard light intensity.

[0108] Based on the above parameters The unified calculation method and its effective logic in different scenarios are as follows:

[0109] when At that time, unit Weighting coefficients Designed as follows:

[0110]

[0111] in, Gain coefficients calculated for weights; For unit The coefficient for normalized power generation cost; For equipment The baseline weights; For equipment The normalized power generation stability coefficient; For unit exist The available reserve power at any given time is defined as the difference between the equipment's current maximum generating power and its current output, calculated using the following formula: ; This represents the rated reserve power; the ratio of the two is used to represent the utilization rate of the available reserve power. It is a pre-defined, extremely small positive number; This is for frequency deviation;

[0112] In this case, due to the preset and The preset values ​​for new energy equipment are significantly lower than those for energy storage equipment, resulting in new energy equipment receiving higher weight and being prioritized for use. The output of different new energy equipment is allocated based on a comprehensive consideration of the utilization rate of available backup power, power generation stability, and power generation cost.

[0113] However, the weight of energy storage devices is relatively low. The high power generation cost coefficient is effectively suppressed. The allocation of backup power is based only on its own reserve power utilization rate and power generation stability. The higher the reserve power utilization rate and the better the power generation stability, the greater the weight and the higher the priority of power output.

[0114] when When the weighting coefficients are designed as follows:

[0115]

[0116] in, Gain coefficients calculated for weights; For unit The baseline weights; For unit The normalized curtailment cost coefficient; For unit exist The state of charge at any given time; when the unit When it is a new energy equipment unit, The value is set to 0.5 to ensure that the coefficient is of the same order of magnitude in energy storage and new energy equipment, thus having a limited impact on reducing output priority.

[0117] In this case, due to the preset and Since the preset values ​​for new energy equipment are greater than those for energy storage equipment, energy storage equipment has a higher weighting. Different energy storage devices are ranked according to their state of charge. Distribute charging power. A higher value indicates more abundant current power, a lower weight, and a lighter charging task assigned to it; while the weight of new energy equipment is effectively suppressed to an extremely low level, and its allocation is mainly based on the cost of power curtailment. The allocation of power reduction is carried out, with higher-cost renewable energy equipment receiving lower weight. To further reduce communication burden, based on the distributed architecture, the frequency regulation participation of each distributed power unit will be dynamically activated or suspended through an event-triggered mechanism.

[0118] Combination Figure 5 The process of the event triggering mechanism in the distributed adaptive frequency modulation method for isolated microgrids of the present invention is described. Each frequency modulation participating unit dynamically activates or suspends the secondary frequency modulation function through a local event trigger, reducing unnecessary communication and computation. The specific process is as follows:

[0119] Frequency deviation trigger: when Time-triggered, designed to initiate secondary frequency regulation when a significant power imbalance occurs in the system;

[0120] Power change trigger: when Time-triggered, designed to capture local power surges and prevent potential frequency fluctuations;

[0121] State of Charge (SOC) exceeding the preset safe range is triggered when the SOC of the energy storage device exceeds the preset safe range. It is triggered at certain times to protect the device from overcharging and over-discharging.

[0122] in, For frequency in The deviation at time; For power in The deviation at time; The minimum safe operating boundary is set based on the chemical properties of the energy storage device, manufacturer specifications, and system backup requirements; The maximum safe operating boundary is set based on the chemical characteristics of the energy storage device, manufacturer specifications, and system backup requirements, and meets... ; The frequency-based dynamic trigger threshold; The power dynamic trigger threshold is dynamically adjusted based on the absolute values ​​of the system frequency deviation change rate and the power change rate: when the change rate increases, the trigger threshold is lowered to speed up the response; when the change rate decreases, the trigger threshold is raised to approach the steady-state reference value.

[0123] When the system is subjected to a large disturbance and the state variables change drastically, the trigger threshold is lowered to improve the system response speed, allowing each unit to quickly initiate coordinated frequency modulation and rapidly suppress frequency abrupt changes. When the system is in a stable or slowly changing state, the trigger threshold is brought closer to the reference value to reduce communication. The specific calculation formula is as follows:

[0124]

[0125]

[0126] middle, This is the reference threshold under steady-state frequency conditions; This is the reference threshold under steady-state power conditions; This is the frequency adjustment factor; This is the power adjustment coefficient; This is the minimum threshold lower limit for frequency. This represents the lower limit of the power threshold. Wherein, This is the reference threshold under steady-state frequency conditions; This is the reference threshold under steady-state power; and Based on the system's steady-state accuracy requirements and communication resource settings; This is the frequency adjustment factor; This is the power adjustment coefficient; the... and A value greater than zero determines the sensitivity of the threshold to the rate of change of the state; This is the minimum threshold lower limit for frequency. This is the lower limit of the minimum threshold for power; and Greater than zero; used to prevent communication congestion or computational overload caused by an excessively small threshold, and also satisfies... , .

[0127] Combination Figure 6 The islanded microgrid distributed adaptive frequency modulation system of the present invention includes:

[0128] The status monitoring and judgment module is used to monitor the frequency deviation of the islanded microgrid, the output power change rate of each distributed power unit, and the state of charge of the energy storage device in real time. When at least one of the frequency deviation, power change rate, or state of charge exceeds the corresponding dynamic adjustable trigger threshold, the corresponding distributed power unit is triggered as a frequency modulation participation unit; otherwise, the frequency modulation dormancy state is maintained.

[0129] The weight calculation module is used to determine the power adjustment direction based on the direction of the frequency deviation. The frequency modulation participation unit calculates the dynamic weight coefficient for allocating output priority based on its own equipment type, operating status parameters and the power adjustment direction.

[0130] The consensus control module is used for the frequency modulation participating unit to exchange its own frequency and power state information with adjacent frequency modulation participating units through a sparse communication network, and to generate frequency recovery control input signal and power allocation control input signal based on the dynamic weight coefficient calculated in step S2 through an adaptive distributed consensus algorithm.

[0131] The integral adjustment module, wherein the frequency modulation participation unit superimposes and integrates the frequency recovery control input signal and the power distribution control input signal generated in step S3 to generate a correction amount for the reference frequency;

[0132] The power allocation execution module inputs the correction amount of the reference frequency to the local active power-frequency droop controller, adjusts the output power of the frequency modulation participating unit, restores the frequency of the islanded microgrid to the rated value, and allocates the output ratio of each frequency modulation participating unit according to the dynamic weighting coefficient.

[0133] Figure 7 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 7 As shown, the electronic device may include: a processor 710, a communication interface 720, a memory 730, and a communication bus 740, wherein the processor 710, the communication interface 720, and the memory 730 communicate with each other through the communication bus 740. The processor 710 can call logical instructions in the memory 730 to execute a distributed adaptive frequency modulation method for an islanded microgrid, the method including:

[0134] Step S1: Monitor the frequency deviation of the isolated microgrid, the output power change rate of each distributed power unit, and the state of charge of the energy storage device in real time. When at least one of the frequency deviation, power change rate, or state of charge exceeds the corresponding dynamic adjustable trigger threshold, trigger the corresponding distributed power unit as a frequency modulation participation unit; otherwise, keep the frequency modulation dormant state.

[0135] Step S2: Determine the power adjustment direction based on the direction of the frequency deviation. The frequency modulation participation unit calculates a dynamic weighting coefficient for allocating power output priority based on its own equipment type, operating status parameters and the power adjustment direction.

[0136] In step S3, the frequency modulation participating unit exchanges its own frequency and power state information with adjacent frequency modulation participating units through a sparse communication network, and generates frequency recovery control input signal and power allocation control input signal based on the dynamic weight coefficient calculated in step S2 through an adaptive distributed consensus algorithm.

[0137] In step S4, the frequency modulation participation unit superimposes and integrates the frequency recovery control input signal and the power distribution control input signal generated in step S3 to generate a correction amount for the reference frequency.

[0138] Step S5: Input the correction amount of the reference frequency to the local active power-frequency droop controller, adjust the output power of the frequency modulation participating unit, so that the frequency of the islanded microgrid is restored to the rated value, and the output ratio of each frequency modulation participating unit is allocated according to the dynamic weighting coefficient.

[0139] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0140] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the aforementioned distributed adaptive frequency modulation method for an isolated microgrid, the method comprising:

[0141] Step S1: Monitor the frequency deviation of the isolated microgrid, the output power change rate of each distributed power unit, and the state of charge of the energy storage device in real time. When at least one of the frequency deviation, power change rate, or state of charge exceeds the corresponding dynamic adjustable trigger threshold, trigger the corresponding distributed power unit as a frequency modulation participation unit; otherwise, keep the frequency modulation dormant state.

[0142] Step S2: Determine the power adjustment direction based on the direction of the frequency deviation. The frequency modulation participation unit calculates a dynamic weighting coefficient for allocating power output priority based on its own equipment type, operating status parameters and the power adjustment direction.

[0143] In step S3, the frequency modulation participating unit exchanges its own frequency and power state information with adjacent frequency modulation participating units through a sparse communication network, and generates frequency recovery control input signal and power allocation control input signal based on the dynamic weight coefficient calculated in step S2 through an adaptive distributed consensus algorithm.

[0144] In step S4, the frequency modulation participation unit superimposes and integrates the frequency recovery control input signal and the power distribution control input signal generated in step S3 to generate a correction amount for the reference frequency.

[0145] Step S5: Input the correction amount of the reference frequency to the local active power-frequency droop controller, adjust the output power of the frequency modulation participating unit, so that the frequency of the islanded microgrid is restored to the rated value, and the output ratio of each frequency modulation participating unit is allocated according to the dynamic weighting coefficient.

[0146] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A distributed adaptive frequency regulation method for isolated microgrids, characterized in that, The method is executed collaboratively by multiple distributed power supply units, including: Step S1: Monitor the frequency deviation of the isolated microgrid, the output power change rate of each distributed power unit, and the state of charge of the energy storage device in real time. When at least one of the frequency deviation, power change rate, or state of charge exceeds the corresponding dynamic adjustable trigger threshold, trigger the corresponding distributed power unit as a frequency modulation participation unit; otherwise, keep the frequency modulation dormant state. Step S2: Determine the power adjustment direction based on the direction of the frequency deviation. The frequency modulation participation unit calculates a dynamic weighting coefficient for allocating power output priority based on its own equipment type, operating status parameters and the power adjustment direction. In step S3, the frequency modulation participating unit exchanges its own frequency and power state information with adjacent frequency modulation participating units through a sparse communication network, and generates frequency recovery control input signal and power allocation control input signal based on the dynamic weight coefficient calculated in step S2 through an adaptive distributed consensus algorithm. In step S4, the frequency modulation participation unit superimposes and integrates the frequency recovery control input signal and the power distribution control input signal generated in step S3 to generate a correction amount for the reference frequency. Step S5: Input the correction amount of the reference frequency to the local active power-frequency droop controller, adjust the output power of the frequency modulation participating unit, so that the frequency of the islanded microgrid is restored to the rated value, and the output ratio of each frequency modulation participating unit is allocated according to the dynamic weighting coefficient.

2. The distributed adaptive frequency modulation method for isolated microgrids according to claim 1, characterized in that, In step S1, when the frequency deviation and the power change rate exceed the corresponding dynamic adjustable trigger threshold, the dynamic adjustable trigger threshold is dynamically adjusted according to the absolute values ​​of the frequency deviation change rate and the power change rate: when the absolute values ​​of the frequency deviation change rate and the power change rate increase, the corresponding dynamic adjustable trigger threshold is lowered; when the absolute values ​​of the frequency deviation change rate and the power change rate decrease, the corresponding dynamic adjustable trigger threshold is raised.

3. The distributed adaptive frequency modulation method for isolated microgrids according to claim 1, characterized in that, When the state of charge exceeds the preset safe operating range, the energy storage device is triggered to participate in or withdraw from frequency regulation.

4. The distributed adaptive frequency modulation method for isolated microgrids according to claim 1, characterized in that, The adjustment strategy for the dynamically adjustable trigger threshold is as follows: when the system state variables change rapidly, the trigger threshold is lowered to accelerate the coordinated frequency modulation response; when the system state variables change gradually, the trigger threshold is raised to reach the steady-state reference value to reduce communication; specific calculations are as follows: in, This is the reference threshold under steady-state frequency conditions; This is the reference threshold under steady-state power conditions; This is the frequency adjustment factor; This is the power adjustment coefficient; This is the minimum threshold lower limit for frequency. This is the lower limit of the minimum threshold for power.

5. The distributed adaptive frequency modulation method for isolated microgrids according to claim 1, characterized in that, The adaptive allocation rule for the dynamic weight coefficients in step S2 is as follows: When the frequency deviation is negative, new energy equipment will increase its output first, and energy storage equipment will serve as a backup. The output of new energy equipment will be allocated according to the backup power utilization rate, power generation stability and power generation cost, and the output of energy storage equipment will be allocated according to the backup power utilization rate and power generation stability. When the frequency deviation is positive, the energy storage device prioritizes charging and absorbing power, while the new energy device serves as a backup. The energy storage devices allocate charging power according to the SOC. When the frequency cannot be restored by energy storage alone, the new energy devices work together to reduce power output and allocate the power reduction according to the cost of curtailment. when At this time, the unit Weighting coefficients The calculation formula is: in, Gain coefficients calculated for weights; For unit The coefficient for normalized power generation cost; For unit The baseline weights; For unit The normalized power generation stability coefficient; For unit exist The available reserve power at any given time is defined as the difference between the equipment's current maximum generating power and its current output, calculated using the following formula: ; Indicates the rated standby power; It is a pre-defined, extremely small positive number; This is for frequency deviation; when At this time, the unit Weighting coefficients The calculation formula is: in, Gain coefficients calculated for weights; For unit The baseline weights; For unit The normalized curtailment cost coefficient; For unit exist The state of charge at any given time; when the unit When it is a new energy equipment unit, The value is 0.

5.

6. The distributed adaptive frequency modulation method for isolated microgrids according to claim 1, characterized in that, In step S3, the adaptive distributed consensus algorithm is the unit participating in frequency modulation. Generated frequency recovery control input and power distribution control input Superimposed to generate total control input The adaptive distributed consensus formula is: in, To be with unit Adjacent unit sets; These are elements of the communication adjacency matrix; For unit exist Angular frequency at time; For unit exist Angular frequency at time t; The weight coefficient for the leadership node; The rated value for the frequency modulation participating unit; For unit exist Active power at any given moment; For unit exist Active power at any given moment; for Consistency control gain; for Consistency control gain; For application to the unit The result of the dynamic weighting function; For application to the unit The result of the dynamic weighting function.

7. The distributed adaptive frequency modulation method for isolated microgrids according to claim 1, characterized in that, In step S4, the function of the integrator is to integrate the sum of the control inputs to generate the reference frequency correction. for: The integral stage continues to operate until the system frequency recovers to the rated value. Furthermore, each frequency modulation participating unit participates in power allocation according to a dynamic weighting coefficient.

8. A control system for a distributed adaptive frequency modulation method in an islanded microgrid, characterized in that, include: The status monitoring and judgment module is used to monitor the frequency deviation of the islanded microgrid, the output power change rate of each distributed power unit, and the state of charge of the energy storage device in real time. When at least one of the frequency deviation, power change rate, or state of charge exceeds the corresponding dynamic adjustable trigger threshold, the corresponding distributed power unit is triggered as a frequency modulation participation unit; otherwise, the frequency modulation dormancy state is maintained. The weight calculation module is used to determine the power adjustment direction based on the direction of the frequency deviation. The frequency modulation participation unit calculates the dynamic weight coefficient for allocating output priority based on its own equipment type, operating status parameters and the power adjustment direction. The consensus control module is used for the frequency modulation participating unit to exchange its own frequency and power state information with adjacent frequency modulation participating units through a sparse communication network, and to generate frequency recovery control input signal and power allocation control input signal based on the dynamic weight coefficient calculated in step S2 through an adaptive distributed consensus algorithm. The integral adjustment module, wherein the frequency modulation participation unit superimposes and integrates the frequency recovery control input signal and the power distribution control input signal generated in step S3 to generate a correction amount for the reference frequency; The power allocation execution module inputs the correction amount of the reference frequency to the local active power-frequency droop controller, adjusts the output power of the frequency modulation participating unit, restores the frequency of the islanded microgrid to the rated value, and allocates the output ratio of each frequency modulation participating unit according to the dynamic weighting coefficient.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the distributed adaptive frequency modulation method for isolated microgrids as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the distributed adaptive frequency modulation method for isolated microgrids as described in any one of claims 1 to 7.

Images