Flywheel-compressed air hybrid energy storage primary frequency modulation control method, system and device based on fuzzy coordination and medium

Abstract

The present application relates to the technical field of energy storage primary frequency modulation control, and particularly to a flywheel-compressed air hybrid energy storage primary frequency modulation control method, system, device and medium based on fuzzy coordination. State characteristic quantities and flywheel state of charge are collected; the current transient type in which compressed air energy storage target safety power, actual active power and energy storage safety state characteristic quantities are located is identified; the total primary frequency modulation power instruction of the hybrid energy storage is calculated according to the grid-connected point frequency and frequency change rate, and fuzzy reasoning is performed with the frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristic quantities and output power reduction urgency as inputs to output the climbing correction coefficient, flywheel compensation coefficient and filter time constant; the compressed air energy storage transient reference power meeting the safety boundary of the device is generated according to the transient type, climbing correction coefficient and allowed climbing rate, the transient power shortage is calculated and compensated by the flywheel energy storage, and the primary frequency modulation control for the compressed air energy storage transient process is completed.

Description

Technical Field

[0001] This invention relates to the field of primary frequency regulation control technology for energy storage, and in particular to a method, system, equipment, and medium for primary frequency regulation control of flywheel-compressed air hybrid energy storage based on fuzzy coordination. Background Technology

[0002] A high proportion of renewable energy grid connection reduces the equivalent inertia of the power system, resulting in faster frequency fluctuations and greater uncertainty. Compressed air energy storage has advantages such as large capacity, long continuous discharge time, and suitability for long-term energy support; however, its output power is constrained by multiple factors including tank pressure, thermal state, expander inlet temperature, valve flow rate, and shaft speed, limiting its power ramp-up speed. Flywheel energy storage offers advantages such as fast response, high power density, and long cycle life, making it suitable for second-level rapid power compensation; however, its energy capacity is relatively small, and prolonged continuous power supply can lead to a rapid approach to the state of charge boundary.

[0003] Unlike conventional thermal or hydropower units, compressed air energy storage power stations may enter a safe power reduction or shutdown preparation process during daily operation due to insufficient gas storage energy, thermal energy storage, hot tank liquid level, expander inlet temperature, or equipment protection conditions. When compressed air energy storage reduces from full power to the safe target power, if the reduction rate is too fast, an active power gap will be formed at the grid connection point, causing a frequency drop; if the power ramp-up is limited by valve groups and thermal processes, the frequency support capability will also be weakened because the actual power lags behind the primary frequency regulation demand.

[0004] Existing flywheel-compressed air hybrid energy storage primary frequency regulation methods mostly employ fixed low-pass filters, fixed droop coefficients, or fuzzy allocation strategies based solely on the flywheel's state of charge. These methods primarily address power allocation issues under steady-state or conventional disturbances, but do not adequately cover the unique constraints of compressed air energy storage during transient processes such as safe power reduction, derating, power ramp-up, and power recovery. If compressed air energy storage is only required to rapidly reduce its output according to a safe target power without simultaneous flywheel compensation and frequency feedback, a mismatch between evidence and conclusion may occur, where "compressed air energy storage safety is met, but system frequency deteriorates." Conversely, if frequency control is emphasized while ignoring the gas and heat storage boundaries of compressed air energy storage, equipment safety constraints may be violated. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the problem this invention aims to solve is how to address the degradation of primary frequency regulation performance in compressed air energy storage during safe output reduction or power ramp-up due to response hysteresis, power deficit, and state constraints. This method, while prioritizing the safety boundaries of the compressed air energy storage device, utilizes flywheel energy storage to compensate for transient power gaps, and dynamically adjusts the output reduction rate, ramp-up trajectory, and flywheel compensation intensity through fuzzy adaptive judgment of frequency deviation, frequency change rate, and energy storage state.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, embodiments of the present invention provide a primary frequency regulation control method for flywheel-compressed air hybrid energy storage based on fuzzy coordination, which includes collecting grid connection point frequency, frequency change rate, actual active power of compressed air energy storage, target safe power, allowable ramp rate, energy storage safety state characteristic quantity and flywheel state of charge. Based on the target safe power and the actual active power, combined with the energy storage safety state characteristic quantities, the current transient state type of compressed air energy storage is identified; Calculate the total frequency regulation power command for hybrid energy storage based on the grid connection point frequency and frequency change rate; Based on the transient type and ramp correction coefficient, a transient reference power for compressed air energy storage is generated. Based on the total frequency regulation power command and the transient reference power, the transient power deficit is calculated, and a rapid compensation power command is issued to the flywheel energy storage. The flywheel energy storage system performs a charging and discharging response according to the instructions.

[0008] As a preferred embodiment of the flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination described in this invention, wherein: the acquisition of grid connection point frequency and frequency change rate includes: continuously acquiring grid connection point frequency at a fixed sampling period, and subtracting the acquired grid connection point frequency from the rated frequency to obtain frequency deviation; The frequency change rate is obtained by calculating the trend of the frequency deviation of continuous sampling. When the frequency deviation is within the frequency tuning dead zone, a standby command is sent to the flywheel energy storage and compressed air energy storage. When the state of charge of the flywheel deviates from the target range, a charge recovery charging and discharging command is sent to the flywheel energy storage. When the frequency deviation exceeds the frequency modulation dead zone, subsequent transient type identification and frequency modulation control steps are triggered.

[0009] As a preferred embodiment of the flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination described in this invention, wherein: the identification of the current transient type of compressed air energy storage includes, when the target safe power of compressed air energy storage is lower than the actual active power and the energy storage safety state characteristic quantity is lower than the safety lower limit, identifying it as a safe power reduction transient. When the target safe power of the compressed air energy storage is higher than the actual active power and the system requires an increase in active power output, it is identified as a power ramp-up transient. When the target safe power of compressed air energy storage is lower than the actual active power and the energy storage safety state characteristic quantity does not trigger the safety boundary, it is identified as a power reduction ramping transient. When the compressed air energy storage returns from a dated state to usable power, it is identified as a power recovery transient. The subsequent climbing trajectory generation and compensation strategy are determined based on the identified transient type.

[0010] As a preferred embodiment of the flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination described in this invention, the method involves calculating the total frequency regulation power command for hybrid energy storage based on the grid connection point frequency and the frequency change rate. This includes performing fuzzy inference using the grid connection point frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristics, and reduction power urgency as inputs, and outputting a ramp correction coefficient, a flywheel compensation coefficient, and a filtering time constant. The frequency deviation is divided into multiple fuzzy subsets according to the direction and amplitude of fluctuation; the frequency change rate is divided into multiple fuzzy subsets according to the rate and direction of change; the flywheel charge state is divided into multiple fuzzy subsets according to the charge and discharge margin; and the energy storage safety state characteristic quantity and the urgency of power reduction are divided into multiple fuzzy subsets according to safety, early warning, and urgency, respectively. Based on three-level priority collaborative reasoning: when the urgency of reducing output exceeds the mandatory threshold, the ramp correction coefficient shall not be lower than the minimum value required for safe reduction output; When the frequency deviation and the frequency change rate both worsen in the same direction, increase the flywheel compensation coefficient and slow down the power reduction ramp rate. After the frequency deviation returns to the dead zone, the flywheel compensation coefficient is reduced and the filter time constant is increased to restore the flywheel's state of charge to the target range. The inference results are defuzzified to obtain the ramp correction coefficient, flywheel compensation coefficient, and filter time constant.

[0011] As a preferred embodiment of the flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination described in this invention, wherein: the energy storage safety state characteristic quantity is jointly determined by the pressure state quantity of the gas storage tank, the heat state quantity of the heat storage tank and the inlet temperature state quantity of the expander, and each state quantity is weighted and synthesized after being normalized according to its respective safety range. The urgency of the reduced output force is determined by the smallest margin from the lower safety limit among the pressure state of the gas storage tank, the heat state of the heat storage tank, and the temperature state of the expander inlet. When the energy storage safety state characteristic quantity is lower than the safety lower limit, the compressed air energy storage is marked as a forced output reduction state, and the minimum allowable power reduction ramp rate is determined according to the urgency of the output reduction. The compressed air energy storage output shall not be forcibly maintained due to frequency requirements.

[0012] As a preferred embodiment of the flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination described in this invention, wherein: the transient reference power is sent to the compressed air energy storage, and the flywheel energy storage performs a charge and discharge response according to the rapid compensation power command, including: adjusting the expander inlet mass flow rate according to the transient reference power, rapidly correcting the valve position according to the shaft speed deviation, and adjusting the heat storage medium flow rate according to the expander inlet temperature; When the pressure of the gas storage tank, the temperature of the heat storage tank, the inlet temperature of the expander, or the speed of the shaft system exceeds the limit, the operation based on the transient reference power will be stopped, and the operation will be switched to protection derating. In case of overspeed or overpressure, unloading and venting will be performed. The flywheel motor torque command is generated based on the fast compensation power command, and then converted into a bidirectional converter current command through the inner current loop. The flywheel energy storage performs a fast charge and discharge response based on the current command.

[0013] As a preferred embodiment of the flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination described in this invention, in the power ramp-up and power recovery transient states, the actual power of the compressed air energy storage is constrained by the valve opening change rate and the expander inlet mass flow rate, and lags behind the total primary frequency regulation power command of the hybrid energy storage. A ramp-up front compensation command is issued to the flywheel energy storage, and the flywheel energy storage bears the transient power deficit during the ramp-up lag period. As the actual power of compressed air energy storage gradually approaches the transient reference power, the compensation power command issued to flywheel energy storage is gradually reduced according to the slope limit until the compensation power returns to zero. After the frequency deviation at the grid connection point returns to the frequency regulation dead zone, a state of charge recovery command is sent to the flywheel energy storage. The flywheel energy storage then charges and discharges at low power to return the state of charge to the target range.

[0014] Secondly, embodiments of the present invention provide a flywheel-compressed air hybrid energy storage primary frequency regulation control system based on fuzzy coordination, which includes a feature characterization module that collects grid connection point frequency, frequency change rate, actual active power of compressed air energy storage, target safe power of compressed air energy storage, allowable ramp rate, energy storage safety state characteristic quantity characterizing the safety state of compressed air energy storage, and flywheel state of charge. The identification module identifies the current transient state type of compressed air energy storage based on the target safe power, actual active power, and energy storage safety state characteristics of the compressed air energy storage. The calculation module calculates the total primary frequency regulation power command for hybrid energy storage based on the grid connection point frequency and frequency change rate. It performs fuzzy inference with the grid connection point frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristics and power reduction urgency as inputs, and outputs the ramp correction coefficient, flywheel compensation coefficient and filter time constant. The issuing module generates a compressed air energy storage transient reference power that meets the equipment safety boundary based on the transient type, ramp correction coefficient and allowable ramp rate. It calculates the transient power deficit based on the total primary frequency regulation power command of the hybrid energy storage and the compressed air energy storage transient reference power. When the flywheel charge state is within the safe range, it issues a fast compensation power command to the flywheel energy storage. The frequency modulation control module sends the transient reference power to the compressed air energy storage, and the flywheel energy storage executes the charging and discharging response according to the fast compensation power command, thus completing the first frequency modulation control for the transient process of compressed air energy storage.

[0015] Thirdly, embodiments of the present invention provide a computer device, including a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, the steps of the fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency modulation control method as described in the first aspect of the present invention are implemented.

[0016] Fourthly, embodiments of the present invention provide a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, the steps of the fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency modulation control method as described in the first aspect of the present invention are implemented.

[0017] The beneficial effects of this invention are as follows: By collecting grid connection point frequency, frequency change rate, and multi-dimensional safety state quantities of compressed air energy storage and identifying its current transient type, subsequent power allocation can detect in advance whether compressed air energy storage is about to enter a safe reduction output or ramp-up limitation stage, avoiding a decrease in frequency support capability due to state lag; by using energy storage safety state characteristics and reduction output urgency as inputs for fuzzy inference, the equipment safety constraints of compressed air energy storage are directly incorporated into power allocation decisions, enabling the output of ramp-up correction coefficient and flywheel compensation coefficient to take into account frequency response requirements while ensuring equipment safety, thus solving the problem of fixed ramp rate and fixed... The problem of the allocation ratio being difficult to adapt to different transient scenarios is addressed by generating a compressed air energy storage transient reference power that meets the equipment safety boundary based on the transient type and ramp correction coefficient. The flywheel energy storage then compensates for the gap between the total frequency regulation command and this reference power in real time, ensuring that the active power gap generated by the compressed air energy storage during power reduction or ramp lag can be filled in a timely manner, preventing the gap from being directly transmitted as a frequency drop. The flywheel compensation power gradually withdraws as the actual power of the compressed air energy storage approaches the reference value, and guides the flywheel's state of charge to recover after the frequency returns to the dead zone, avoiding secondary frequency fluctuations caused by the sudden withdrawal of compensation power, and also preventing the flywheel from deviating from the healthy charge range for a long time. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart for a fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control method; Figure 2 A computer device diagram for a fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control method; Figure 3 A schematic diagram of an energy storage system structure for a fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control method; Figure 4 Control structure diagram for a fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control method; Figure 5 A diagram illustrating the reduced output monitoring and power regulation scheme for a fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control method. Figure 6 Flowchart of flywheel auxiliary control for transient output reduction process in primary frequency regulation control method of flywheel-compressed air hybrid energy storage for fuzzy coordination; Figure 7Simulation comparison of primary frequency regulation under different control schemes in the conventional case of the fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control method; Figure 8 Initialization of a fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control method Comparison chart of primary frequency modulation under the condition of <0.25; Figure 9 Initialization of a fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control method A schematic diagram of primary frequency modulation under the condition of >0.75; Figure 10 A schematic diagram of the simulation curve of the power reduction process for the primary frequency regulation control method of fuzzy coordinated flywheel-compressed air hybrid energy storage. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0023] Example 1 Reference Figure 1 This is the first embodiment of the present invention, which provides a primary frequency regulation control method for flywheel-compressed air hybrid energy storage based on fuzzy coordination, including: The system collects the grid connection point frequency, frequency change rate, actual active power of compressed air energy storage, target safe power of compressed air energy storage, allowable ramp rate, energy storage safety state characteristic quantities characterizing the safety state of compressed air energy storage, and flywheel state of charge.

[0024] Based on the target safe power, actual active power and energy storage safety status characteristics of compressed air energy storage, the current transient state type of compressed air energy storage is identified.

[0025] Based on the grid connection point frequency and frequency change rate, the total primary frequency regulation power command of hybrid energy storage is calculated. Fuzzy inference is performed with the grid connection point frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristics and the urgency of power reduction as inputs, and the outputs include ramp correction coefficient, flywheel compensation coefficient and filter time constant.

[0026] Based on the transient type, ramp correction coefficient, and allowable ramp rate, a compressed air energy storage transient reference power that meets the equipment safety boundary is generated. The transient power deficit is calculated based on the total primary frequency regulation power command of the hybrid energy storage and the compressed air energy storage transient reference power. When the flywheel's state of charge is within the safe range, a rapid compensation power command is issued to the flywheel energy storage.

[0027] A transient reference power is issued to the compressed air energy storage, and the flywheel energy storage executes a charging and discharging response based on the fast compensation power command, thus completing the first frequency regulation control for the transient process of compressed air energy storage.

[0028] It should be noted that the output power of compressed air energy storage during the energy release and power generation stage is not always stable. It is constrained by the triple physical boundaries of the gas storage tank pressure, the available heat of the heat storage tank, and the inlet temperature of the expander. During daily operation, it may enter a state of safe reduced output or power limitation due to the consumption of gas storage energy, insufficient heat storage, or low inlet temperature.

[0029] First, the grid connection point frequency, frequency change rate, and multi-dimensional state variables of compressed air energy storage and flywheel energy storage are collected. The current transient type is identified based on the target safe power, actual active power, and energy storage safety state characteristics. Then, the total primary frequency regulation power command for hybrid energy storage is calculated, and fuzzy inference is performed using five inputs: frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristics, and urgency of power reduction. The ramp correction coefficient, flywheel compensation coefficient, and filter time constant are output according to a three-level priority system: equipment safety first, frequency safety second, and state of charge recovery last. Based on the transient type and ramp correction coefficient, a compressed air energy storage transient reference power that meets the equipment safety boundary is generated. The difference between the total command and the transient reference power is taken as the transient power deficit. Within the safe range of the flywheel state of charge, a fast compensation power command is issued to the flywheel energy storage. The flywheel energy storage fills the deficit with a millisecond-level charge and discharge response. The compressed air energy storage simultaneously performs valve group regulation according to the transient reference power, thus completing the primary frequency regulation control that maintains frequency support even when the compressed air energy storage must be derated or ramping is limited.

[0030] Example 2 Reference Figure 1 - Figure 6 This is the second embodiment of the present invention.

[0031] In this embodiment, step S100, which involves collecting the grid connection point frequency, frequency change rate, actual active power of compressed air energy storage, target safe power of compressed air energy storage, allowable ramp rate, energy storage safety state characteristic quantities characterizing the safety state of compressed air energy storage, and flywheel state of charge, includes the following A1 steps: A1: Collect grid connection point frequency and frequency change rate, including continuously collecting grid connection point frequency at a fixed sampling period, and subtracting the collected grid connection point frequency from the rated frequency to obtain the frequency deviation; The frequency change rate is obtained by calculating the trend of the frequency deviation of continuous sampling. When the frequency deviation is within the frequency modulation dead zone, a standby command is sent to the flywheel energy storage and compressed air energy storage. When the state of charge of the flywheel deviates from the target range, a charge recovery charging and discharging command is sent to the flywheel energy storage. When the frequency deviation exceeds the frequency modulation dead zone, subsequent transient type identification and frequency modulation control steps are triggered.

[0032] Specifically, refer to Figure 3 This implementation method is applied to an integrated hybrid energy storage frequency regulation scenario consisting of a flywheel energy storage unit, an advanced-adiabatic-compressed-air-energy-Storage (AA-CAES) unit, a hybrid energy storage coordination controller, a bidirectional converter, and a grid-connected measurement device. The flywheel energy storage unit consists of a high-strength carbon fiber composite rotor, a permanent-magnetic-synchronous-motor (PMSM), a bidirectional converter, and a flywheel speed sensor. The flywheel rotor is mounted in a vacuum-sealed chamber via magnetic levitation bearings or rolling bearings. The PMSM shaft is rigidly connected to the rotor. The bidirectional converter connects to the motor stator winding on the AC side and to the power distribution network on the DC side, realizing bidirectional conversion of electrical energy and kinetic energy.

[0033] The compressed air energy storage unit consists of a high-pressure air tank, a heat storage tank, a multi-stage expander, a compressor, and a valve group (power control valve PCV, speed control valve SCV, temperature control valve TCV, shut-off valve CV, and exhaust valve EV). The air tank is connected to the expander inlet through a high-pressure pipeline, and the heat storage tank provides high-temperature heat storage medium to the expander through a heat exchanger.

[0034] Under the above structure, the hybrid energy storage coordination controller operates at a sampling period of 10ms. =0.01s) is a fixed sampling period, and the frequency of the grid connection point is measured by a sensor array. Actual active power of compressed air energy storage Gas storage tank pressure Heat storage tank can store heat Expander inlet temperature and flywheel real-time angular velocity Perform synchronous data collection.

[0035] The grid connection point frequency at each sampling time With rated frequency (Taking 50Hz) The difference is used to obtain the frequency deviation. The frequency change rate is obtained by dividing the first-order difference of the frequency deviation of continuous sampling by the sampling period. This refers to the rate of change of frequency deviation (RoCoF). The sign of the frequency deviation reflects the direction of the deviation from the rated value, while the magnitude of the absolute value reflects the degree of deviation. The sign of the frequency reflects the direction of the frequency fluctuation, and the absolute value reflects the fluctuation rate. Both serve as the basic input for subsequent frequency modulation command calculation and fuzzy inference.

[0036] The coordinating controller synchronously acquires the target safe power of compressed air energy storage. Compared with the allowable gradeability (baseline power reduction gradeability) and power ramp rate ), and based on the real-time angular velocity of the flywheel Calculate the flywheel's state of charge (SOC). The state of charge (SBC) of a flywheel represents the ratio of its current stored kinetic energy to its rated kinetic energy. Its calculation is based on the mapping relationship between flywheel speed and SBC. At this point, all the data collected by S100 is in place, providing complete status input for S200 transient identification.

[0037] In this embodiment, step S200 identifies the current transient state type of compressed air energy storage based on the target safe power, actual active power, and energy storage safety state characteristics, including the following step B1: B1: Identify the current transient state type of compressed air energy storage, including identifying it as a safe power reduction transient when the target safe power of compressed air energy storage is lower than the actual active power and the energy storage safety state characteristic quantity is lower than the safety lower limit; When the target safe power of compressed air energy storage is higher than the actual active power and the system requires an increase in active power output, it is identified as a power ramp-up transient. When the target safe power of compressed air energy storage is lower than the actual active power and the energy storage safety state characteristic quantity has not triggered the safety boundary, it is identified as a power reduction ramping transient. When compressed air energy storage returns from a dated state to usable power, it is identified as a power recovery transient. The subsequent climbing trajectory generation and compensation strategy are determined based on the identified transient type.

[0038] Specifically, the energy storage safety state characteristic quantity is the equivalent state of charge of compressed air energy storage. It is a comprehensive measurement of three dimensions: the pressure state of the gas storage tank, the heat state of the heat storage tank, and the inlet temperature state of the expander.

[0039] The three state variables are respectively classified according to their respective safety ranges. , ]、[ , ]、[ , After normalization, a weighted composite is formed, with the weights... , , satisfy + + =1, the weight values ​​are adjusted based on the degree of influence of each dimension on the compressed air energy storage output capacity, and in this embodiment, it is taken as 1. =0.5、 =0.3、 =0.2: This comprehensively reflects the current available energy margin of compressed air energy storage: The lower the value, the closer the gas storage, thermal storage, or expander inlet temperature is to the safe lower limit, and the higher the risk of continuing to maintain the current output power.

[0040] Based on this, refer to Figure 5 The coordinating controller calculates the urgency η of the reduced output force. η is defined as the normalized value of the smallest distance from the lower safety margin among the three dimensions: gas tank pressure, available heat in the heat storage tank, and expander inlet temperature. The maximum value of the three-dimensional distance is taken as the quantitative expression of η. in, The current pressure of the gas storage tank. The current available heat in the heat storage tank, This refers to the expander inlet temperature. , , These represent the early warning margins for each dimension.

[0041] The larger η is, the closer the compressed air energy storage is to the forced safety reduction force boundary; when η exceeds the forced threshold, the coordinating controller must reduce the output force and must not forcibly maintain the output simply because of frequency requirements.

[0042] Coordination controller based on and The direction of the difference, combined with With η, the transient type is identified according to the following logic: < and When the output is below the safety lower limit, it is identified as a safety reduction transient. > Furthermore, it is required that when the active power output is increased, it be identified as a power ramp-up transient. < but When the safety boundary is not triggered, it is identified as a power reduction ramping transient; when the compressed air energy storage returns from the dated state to the available power, it is identified as a power recovery transient. The transient type identification result serves as a prerequisite for generating the S300 ramping trajectory and is also updated to the state feedback closed loop for use in the next control cycle.

[0043] In this embodiment, step S300 calculates the total primary frequency regulation power command for hybrid energy storage based on the grid connection point frequency and frequency change rate. Fuzzy inference is performed using the grid connection point frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristics, and reduction power urgency as inputs. The outputs include ramp correction coefficients, flywheel compensation coefficients, and filter time constants, comprising the following steps C1-C2: C1: Fuzzy inference is performed using grid connection point frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristics, and reduction force urgency as inputs. Outputs include ramp correction coefficients, flywheel compensation coefficients, and filter time constants, including... The frequency deviation is divided into multiple fuzzy subsets according to the direction and amplitude of the fluctuation; the frequency change rate is divided into multiple fuzzy subsets according to the rate and direction of change; the flywheel charge state is divided into multiple fuzzy subsets according to the charge and discharge margin; and the energy storage safety state characteristic quantity and the urgency of power reduction are divided into multiple fuzzy subsets according to safety, early warning, and urgency, respectively. Based on three-level priority collaborative reasoning: when the urgency of reducing output exceeds the mandatory threshold, the ramp correction coefficient shall not be lower than the minimum value required for safe reduction output; When the frequency deviation and the frequency change rate both worsen in the same direction, increase the flywheel compensation coefficient and slow down the power reduction ramp rate. After the frequency deviation returns to the dead zone, the flywheel compensation coefficient is reduced and the filter time constant is increased to restore the flywheel's state of charge to the target range. The inference results are defuzzified to obtain the ramp correction coefficient, flywheel compensation coefficient, and filter time constant.

[0044] Specifically, refer to Figure 4 The generation of the total primary frequency regulation power command for hybrid energy storage adopts a combination of droop control and virtual inertia control. This is done when the frequency deviation is within the frequency regulation dead zone. ,+ ]( (Take ±0.033Hz) and In the dead zone of rate of change [- ,+ Within this timeframe, the coordinating controller sends standby commands to both the flywheel energy storage and compressed air energy storage; hybrid energy storage does not participate in frequency regulation. If the target range is deviated from, the coordination controller sends a low-power state-of-charge recovery command to the flywheel energy storage, causing... Gradually return to the target range.

[0045] When the frequency deviation exceeds the frequency modulation dead zone, the coordination controller uses the droop coefficient. Frequency deviation Proportional response is performed using virtual inertia coefficients. Differential response to the rate of change of frequency RoCoF(k), the sum of which is truncated by the limiting function sat[·] within the maximum output range of the hybrid energy storage. ,+ ], thus obtaining the primary frequency modulation incremental power ;Will Superimposed on the hybrid energy storage benchmark active power The target active power for primary frequency regulation of hybrid energy storage is obtained. : Positive values ​​represent active power injected into the grid, while negative values ​​represent active power absorbed from the grid. In this embodiment... Take 4000 p.u. Take 4000 p.u. Take 11MW (the sum of 1MW flywheel and 10MW compressed air).

[0046] The fuzzy coordination controller takes five state variables as inputs and three adjustment variables as outputs, operating with an update cycle of 0.1 seconds (i.e., updating once every 10 sampling cycles). The fuzzification method for the five inputs is as follows: Frequency deviation The universe of discourse is set to [-1, +1] Hz, and is divided into five fuzzy subsets according to the direction and amplitude of the fluctuation: negative large (NB), negative small (NS), zero (ZO), positive small (PS), and positive large (PB). The membership function adopts a triangular function. Rate of change of frequency The universe of discourse is set to [-1,+1] Hz / s, and is also divided into five fuzzy subsets: NB / NS / ZO / PS / PB. The universe of discourse is set to [0.2, 0.8], and it is divided into three fuzzy subsets: low (L), medium (M), and high (H) according to the charge / discharge margin. The membership function adopts a hybrid function of trapezoidal and triangular functions. (i.e., the energy storage safety state characteristic quantity) takes the universe of discourse as [0,1], and is divided into three fuzzy subsets according to the safety margin: safety (S), early warning (W), and urgency (U); The domain of the reduced force urgency η is set to [0,1], and is also divided into three fuzzy subsets: safety (S), early warning (W), and urgency (U).

[0047] In the three-channel output, the ramp correction coefficient The universe of discourse is [0,2], and the flywheel compensation coefficient is... The universe of discourse is [0,1], and the filtering time constant is... The universe of discourse is set to [0.1, 10]s, and the output membership function is a Gaussian function to ensure smooth output. Inference is performed using the Mamdani fuzzy inference method, which synthesizes the output fuzzy set by taking the smaller membership degree of the rule antecedent and the larger membership degree between rules. Defuzzification is performed using the centroid method, taking the universe of discourse value corresponding to the centroid of the area of ​​the output fuzzy set as the adjustment output for the current cycle.

[0048] C2: The energy storage safety state characteristic quantities are jointly determined by the gas storage tank pressure state quantity, the heat storage tank heat state quantity, and the expander inlet temperature state quantity. Each state quantity is normalized according to its own safety range and then weighted and synthesized. The urgency of reducing output force is determined by the smallest margin from the lower safety limit among the pressure state of the gas storage tank, the heat state of the heat storage tank, and the temperature state of the expander inlet. When the energy storage safety state characteristic quantity is lower than the safety lower limit, the compressed air energy storage is marked as a forced output reduction state, and the minimum allowable power reduction ramp rate is determined according to the urgency of the output reduction. The output of compressed air energy storage shall not be forcibly maintained due to frequency requirements.

[0049] Specifically, refer to Figure 6 The fuzzy rules are designed collaboratively with a three-layer priority system. The first layer (device safety priority): when η exceeds the mandatory threshold (0.8 in this embodiment), It must not be lower than the minimum value required for safe reduction force. / At this point, regardless of the frequency, compressed air energy storage must implement a safe reduction in output force. according to The maximum available value is used for limiting, and the flywheel compensates for the power deficit.

[0050] Second layer (frequency security is secondary): <0 and <0 (frequency continues to decline) and When in the middle to high range, reduce (Slow down the rate of power reduction in compressed air energy storage), increase (Strengthen flywheel discharge compensation), reduce (Accelerate flywheel response); >0 and >0 (frequency continues to rise) and If the upper limit is not reached, increase (Accelerate compressed air energy storage and reduce output), increase (The flywheel absorbs excess power during charging.) <0 and When approaching the lower limit, reduce Limit flywheel discharge Based on safety boundaries, compressed air energy storage maintains or mitigates derating.

[0051] Third layer (state of charge recovery): After the frequency deviation returns to the dead zone, reduce... Increase The coordinating controller sends a state-of-charge recovery command to the flywheel energy storage, enabling... The target range is gradually returned to using low power.

[0052] Power-up ramp-up lag scenario ( Lagging behind and When available, increase and reduce The flywheel provides compensation power at the ramp-up front, and as the actual power of the compressed air energy storage gradually approaches the reference power, it gradually decreases according to the slope limit. Exit at zero. The above rules constitute a total of 5×3×3×3=135 basic rules. After rule trimming, 49 effective rules covering the main operating conditions are retained and stored in the rule base for table lookup and reasoning in each control cycle.

[0053] In this embodiment, step S400 generates a compressed air energy storage transient reference power that satisfies the equipment safety boundary based on the transient type, ramp correction coefficient, and allowable ramp rate. It calculates the transient power deficit based on the total primary frequency regulation power command for hybrid energy storage and the compressed air energy storage transient reference power. When the flywheel's state of charge is within a safe range, a rapid compensation power command is issued to the flywheel energy storage, including the following step D1: D1: Send transient reference power to compressed air energy storage, and flywheel energy storage performs charging and discharging response according to the rapid compensation power command, including adjusting the mass flow rate of the expander inlet according to the transient reference power, quickly correcting the valve position according to the shaft speed deviation, and adjusting the flow rate of the heat storage medium according to the expander inlet temperature. When the pressure of the gas storage tank, the temperature of the heat storage tank, the inlet temperature of the expander, or the speed of the shaft system exceeds the limit, the operation based on the transient reference power will be stopped, and the operation will be switched to protection derating. In case of overspeed or overpressure, unloading and venting will be performed. The flywheel motor torque command is generated based on the fast compensation power command, and then converted into a bidirectional converter current command through the inner current loop. The flywheel energy storage performs a fast charge and discharge response based on the current command.

[0054] Specifically, the coordination controller, based on the transient type identified by B1 and the outputs of C1-C2... Generate the practically executable power reduction ramp rate for compressed air energy storage as follows: With power ramp rate : Reduced power ramp rate from the baseline through After correction, the amplitude is truncated by the limiting function at [ , The result obtained between ] is: in, The minimum power reduction ramp rate is determined by the urgency η of the reduced output (the larger η is, the lower the ramp rate). The larger the amount, the faster the reduction in the credit limit will be required. Based on the benchmark up-power ramp rate through After correction, truncation is set to [0, ]between: In this embodiment Take 10% / min of the rated power. Take 8% / min of the rated power. Take 15% / min of the rated power. Take 12% / min of the rated power.

[0055] in accordance with and The coordinating controller generates the compressed air energy storage transient reference power recursively. : the previous cycle Based on this, the target safe power and The difference is truncated at [-] by the amplitude limiting function. · , · The values ​​between [ ] are summed to obtain the current period's [ ]. : This recursive approach ensures that the compressed air energy storage power trajectory does not exceed the allowable variations of the valve and thermodynamic processes in each control cycle, while simultaneously converging towards the target safe power, thus balancing safety boundary constraints and frequency regulation response requirements. Storage pressure safety boundary constraints require... Always maintain [ , Between [a certain point], the expander inlet temperature requirement Not less than When any boundary triggers an out-of-limit event, the coordination controller stops pressing. Execute, switch to protection derating operation, and trigger the exhaust valve EV to perform unloading and exhaust in case of overspeed or overpressure.

[0056] Transient power deficit = - This is the difference between the total target power of hybrid energy storage and the executable power of compressed air energy storage. The coordination controller is based on... Determine if the flywheel's state of charge is within a safe range. , (In this embodiment, the range is [0.2, 0.8]): Flywheel discharge is permitted when the discharge level is above the lower limit. The flywheel is allowed to charge when the power is below the upper limit, and the upper and lower limits of the flywheel's charging and discharging power are determined accordingly. and .

[0057] Flywheel state-of-charge recovery power From the target state of charge With the present The difference via proportionality coefficient Magnified, we get: In this embodiment, 0.5 is used.

[0058] Flywheel compensation power Transient power deficit and state-of-charge recovery power The sum is obtained by truncation of the upper and lower limits of charge and discharge power: A positive value indicates that the flywheel discharges and injects active power into the grid, while a negative value indicates that the flywheel charges and absorbs active power from the grid.

[0059] when When it is below the lower limit, Set the discharge level to zero and prevent the flywheel from continuing to discharge. when When it exceeds the upper limit, Set the charge to zero and prevent the flywheel from continuing to charge.

[0060] In this embodiment, step S500 sends a transient reference power to the compressed air energy storage, and the flywheel energy storage executes a charge and discharge response according to the fast compensation power command, completing the primary frequency regulation control for the transient process of compressed air energy storage, including the following E1 steps: E1: During the power ramp-up and power recovery transient, the actual power of compressed air energy storage is constrained by the valve opening change rate and the mass flow rate at the expander inlet, lagging behind the total primary frequency regulation power command of hybrid energy storage. A ramp-up compensation command is issued to flywheel energy storage, and flywheel energy storage assumes the transient power deficit during the ramp-up lag period. As the actual power of compressed air energy storage gradually approaches the transient reference power, the compensation power command issued to flywheel energy storage is gradually reduced according to the slope limit until the compensation power returns to zero. After the frequency deviation at the grid connection point returns to the frequency regulation dead zone, a state of charge recovery command is sent to the flywheel energy storage. The flywheel energy storage then charges and discharges at low power to return the state of charge to the target range.

[0061] Specifically, the coordination controller will Convert to compressed air energy storage valve assembly execution commands: Power control valve PCV based Adjust the mass flow rate at the expander inlet so that the expander output power tracks the transient reference power; The speed control valve (SCV) quickly corrects the valve position based on the speed deviation of the compressed air shaft system, thus suppressing shaft speed fluctuations. The temperature control valve TCV is based on the expander inlet temperature. Adjust the flow rate of the heat storage medium to maintain the inlet temperature within a safe range.

[0062] Flywheel execution layer based on Generate flywheel motor torque command : Employing a zero d-axis control strategy (i.e., setting the direct-axis component of the stator current to zero), the electromagnetic torque is determined solely by the q-axis current. The torque command is calculated by the power outer loop and then sent to the current inner loop. The current inner loop generates the q-axis current command of the bidirectional converter (BDC), which drives the BDC through space vector pulse width modulation (SVPWM) to achieve fast charging and discharging response of flywheel energy storage, with a response time of up to milliseconds.

[0063] During the power ramp-up and power recovery transients, the actual power of compressed air energy storage... Due to the physical inertia of the valve opening change rate and the expander inlet mass flow rate, it lags behind... Transient power deficit = - The initial climb is relatively steep, and the flywheel stores energy primarily... • The intensity of the transient power deficit provides compensation power at the ramp front: Follow Approaching gradually The coordinating controller gradually decreases according to the slope limit. Until the compensation power reaches zero, the flywheel exits the frequency regulation response, and the compressed air energy storage fully undertakes the primary frequency regulation power, realizing a smooth power handover between the two types of energy storage and avoiding secondary frequency fluctuations caused by the sudden exit of the flywheel.

[0064] Grid connection point frequency deviation After the frequency modulation dead zone is reached and |RoCoF(k)| is below the rate of change dead zone, the coordinating controller sends a state-of-charge recovery command to the flywheel energy storage, which then... Using low-power charging and discharging Regression target range : The state feedback closed loop updates the status feedback at the end of each control cycle. , , , and The data is written back to the coordinating controller for use in the next cycle for transient identification, fuzzy reasoning, and trajectory generation, completing a primary frequency modulation closed-loop control for the entire process of compressed air energy storage output reduction and hill climbing.

[0065] Example 3 Reference Figure 7 - Figure 10 This is the third embodiment of the present invention.

[0066] The figure shows the frequency regulation under different control schemes. The load undergoes a 10kW step change in 500s. The frequency regulation effect under different power distribution control schemes is compared. Scheme 1 is a system without energy storage; Scheme 2 is virtual droop control; Scheme 3 is virtual inertia + virtual droop control; and Scheme 4 is adaptive FLC control. The hybrid energy storage droop coefficient KH and the flywheel energy storage virtual inertia coefficient MF are both set to 4000. The delay parameters R1 and R2 are 0.05 and 0.045, respectively. The initial Kf and Kc values ​​are the same for Scheme 3 and Scheme 4, set to 0.5. To avoid system instability caused by frequent adjustments during the regulation process, the output Kf value is first filtered by a first-order filter before being applied to the control. The time constant of this first-order filter is set to 0.5s.

[0067] Combination Figure 7 The data in Table 1 compares the FLC scheme with those without energy storage, droop control, and inertia + droop control. The figures show that during the frequency degradation phase, the inertia + droop control scheme has the fastest adjustment speed and the best frequency support; while during the frequency recovery phase, the adaptive FLC control significantly outperforms other control methods in frequency regulation. Furthermore, a comparison of the data in Tables 4-5 reveals that the scheme without energy storage has the worst frequency response with a maximum frequency deviation of -0.22473Hz and a steady-state deviation of -0.19062Hz. The scheme with droop control has a maximum frequency deviation of -0.06255Hz and a steady-state deviation of -0.03636Hz. The inertia + droop control schemes have frequencies of -0.06578Hz and -0.04310Hz, respectively. The FLC scheme exhibits the best performance in both metrics: a maximum frequency deviation of -0.05158Hz, which is 17.5% lower than droop control and 21.6% lower than inertia + droop; and a steady-state deviation of -0.03359Hz, which is 7.6% lower than droop control and 22.1% lower than inertia + droop. The FLC scheme outperforms the other three schemes in both transient and steady-state performance, demonstrating strong frequency support capabilities.

[0068] Table 1 Comparison of evaluation indicators for primary frequency regulation under different control strategies

[0069] Figure 8 and Figure 9 Initially <0.25 and The frequency regulation performance under conditions >0.75 is analyzed by comparing the continuous frequency regulation effects of the four control schemes mentioned above, with the load power fluctuating between [-5kW, 5kW]. The specific analysis is as follows: 1) When When the state parameter is below 0.25: When Δf > 0, the flywheel energy storage output depth is greater than other controls; when Δf < 0, the flywheel energy storage output depth is basically the same as other controls. By limiting the flywheel energy storage output, stable system regulation is achieved. (See...) Figure 8 .

[0070] 2) When the SOC state parameter is higher than 0.75: When the value is greater than 0, the flywheel energy storage output is higher than other control outputs. When the value is less than 0, the flywheel energy storage output is similar to that of the droop control, effectively limiting the flywheel energy storage output and ensuring system operational safety. (See...) Figure 9 .

[0071] Overall simulation results show that, under continuous disturbances, the primary frequency regulation effect of the FLC strategy is optimal regardless of whether the initial SOC parameter of the flywheel energy storage is below 0.25 or above 0.75.

[0072] Furthermore, the flywheel energy storage SOC deviation under the FLC strategy is generally better than other schemes. In the disturbance range unfavorable to flywheel energy storage output, its output characteristics are comparable to droop control; in the range suitable for flywheel energy storage output, the flywheel energy storage increases the output depth, thereby restoring the SOC state. Its SOC change trend is more inclined towards the healthy SOC range.

[0073] As shown in Table 2, the proposed FLC scheme exhibits excellent primary frequency regulation performance under both high and low initial SOCf conditions. Compared to the scheme without energy storage, the maximum frequency deviation of the FLC scheme is reduced by 74.8% and 73.6%, respectively, and further reduced by 26.7% and 23.6% compared to traditional droop control, significantly improving the suppression capability of frequency transient fluctuations. The root mean square frequency is reduced by 66.8% and 71.2% compared to the scheme without energy storage, respectively, and reduced by 17.7% and 10.2% compared to droop control, respectively, greatly improving the overall frequency fluctuation level of the system. Meanwhile, the average SOC of the FLC scheme... It is closer to the initial healthy range, effectively ensuring the operational safety and sustainable frequency regulation capability of the energy storage system.

[0074] Table 2 Comparison of primary frequency regulation evaluation indicators under different initial SOC states

[0075] Compressed air energy storage safety output reduction primary frequency regulation control. Assuming the rated power of compressed air energy storage is 10MW, due to insufficient gas pressure or heat storage status, it needs to reduce from full power to the safe target power. Candidate power reduction rates are 15% / min, 10% / min, and 5% / min. Flywheel energy storage has a rated power of 1MW, stored energy of 0.025MWh, and a flywheel state-of-charge (SOC) operating range of 0.2 to 0.8. The grid rated frequency is 50Hz, with a frequency dead zone of ±0.033Hz. The controller sampling period is 0.01s, and the fuzzy controller update period is 0.1s.

[0076] When the compressed air energy storage reduces its output at a relatively high rate and the frequency begins to drop, the controller identifies it as a "safe output reduction - frequency deterioration" condition. If the flywheel SOC is in the medium to high range, the flywheel immediately discharges to compensate, and the compressed air energy storage power reduction rate slows down within the safe boundary allowable range. When the frequency recovers to near the dead zone, the flywheel compensation power gradually withdraws. Figure 10 The diagram shows a simulation curve of the reduced output force given in the document.

[0077] Safety protection and abnormal handling

[0078] Example 4 Reference Figure 2 This is the fourth embodiment of the present invention.

[0079] The above is a schematic scheme of a primary frequency regulation control method for flywheel-compressed air hybrid energy storage based on fuzzy coordination. It should be noted that the technical solution of this fuzzy coordination flywheel-compressed air hybrid energy storage primary frequency regulation control system belongs to the same concept as the technical solution of the aforementioned fuzzy coordination flywheel-compressed air hybrid energy storage primary frequency regulation control method. Details not described in detail in the technical solution of the fuzzy coordination flywheel-compressed air hybrid energy storage primary frequency regulation control system in this embodiment can be found in the description of the technical solution of the aforementioned fuzzy coordination flywheel-compressed air hybrid energy storage primary frequency regulation control method.

[0080] This embodiment also provides a flywheel-compressed air hybrid energy storage primary frequency regulation control system based on fuzzy coordination, including: a feature characterization module, which collects grid connection point frequency, frequency change rate, actual active power of compressed air energy storage, target safe power of compressed air energy storage, allowable ramp rate, energy storage safety state characteristic quantity characterizing the safety state of compressed air energy storage and flywheel state of charge. The identification module identifies the current transient state type of compressed air energy storage based on the target safe power, actual active power, and energy storage safety state characteristics. The calculation module calculates the total primary frequency regulation power command for hybrid energy storage based on the grid connection point frequency and frequency change rate. It performs fuzzy inference with the grid connection point frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristics and the urgency of power reduction as inputs, and outputs the ramp correction coefficient, flywheel compensation coefficient and filter time constant. The module generates a compressed air energy storage transient reference power that meets the equipment safety boundary based on the transient type, ramp correction coefficient and allowable ramp rate. It calculates the transient power deficit based on the total primary frequency regulation power command of the hybrid energy storage and the compressed air energy storage transient reference power. When the flywheel charge state is within the safe range, it issues a fast compensation power command to the flywheel energy storage. The frequency control module sends transient reference power to the compressed air energy storage, and the flywheel energy storage executes charging and discharging responses according to the fast compensation power command, completing the first frequency control for the transient process of compressed air energy storage.

[0081] This embodiment also provides an electronic device suitable for fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency regulation control method proposed in the above embodiment.

[0082] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the flywheel-compressed air hybrid energy storage primary frequency modulation control method for achieving fuzzy coordination as proposed in the above embodiments.

[0083] The storage medium proposed in this embodiment belongs to the same inventive concept as the flywheel-compressed air hybrid energy storage primary frequency regulation control method for achieving fuzzy coordination proposed in the above embodiments. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0084] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0085] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A primary frequency regulation control method for flywheel-compressed air hybrid energy storage based on fuzzy coordination, characterized in that: This includes collecting data on grid connection frequency, frequency change rate, actual active power of compressed air energy storage, target safe power, allowable ramp rate, energy storage safety status characteristics, and flywheel state of charge. Based on the target safe power and the actual active power, combined with the energy storage safety state characteristic quantities, the current transient state type of compressed air energy storage is identified; Calculate the total frequency regulation power command for hybrid energy storage based on the grid connection point frequency and frequency change rate; Based on the transient type and ramp correction coefficient, a transient reference power for compressed air energy storage is generated. Based on the total frequency regulation power command and the transient reference power, the transient power deficit is calculated, and a rapid compensation power command is issued to the flywheel energy storage. The flywheel energy storage system performs a charging and discharging response according to the instructions.

2. The flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination as described in claim 1, characterized in that: The acquisition of grid connection point frequency and frequency change rate includes continuously acquiring grid connection point frequency at a fixed sampling period, and subtracting the acquired grid connection point frequency from the rated frequency to obtain frequency deviation. The frequency change rate is obtained by calculating the trend of the frequency deviation of continuous sampling. When the frequency deviation is within the frequency tuning dead zone, a standby command is sent to the flywheel energy storage and compressed air energy storage. When the state of charge of the flywheel deviates from the target range, a charge recovery charging and discharging command is sent to the flywheel energy storage. When the frequency deviation exceeds the frequency modulation dead zone, subsequent transient type identification and frequency modulation control steps are triggered.

3. The flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination as described in claim 2, characterized in that: The identification of the current transient state type of compressed air energy storage includes identifying it as a safe power reduction transient when the target safe power of compressed air energy storage is lower than the actual active power and the energy storage safety state characteristic quantity is lower than the safety lower limit. When the target safe power of the compressed air energy storage is higher than the actual active power and the system requires an increase in active power output, it is identified as a power ramp-up transient. When the target safe power of compressed air energy storage is lower than the actual active power and the energy storage safety state characteristic quantity does not trigger the safety boundary, it is identified as a power reduction ramping transient. When the compressed air energy storage returns from a dated state to usable power, it is identified as a power recovery transient. The subsequent climbing trajectory generation and compensation strategy are determined based on the identified transient type.

4. The flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination as described in claim 3, characterized in that: The calculation of the total frequency regulation power command for hybrid energy storage based on the grid connection point frequency and frequency change rate includes: performing fuzzy inference with grid connection point frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristics, and reduction power urgency as inputs; and outputting ramp correction coefficients, flywheel compensation coefficients, and filtering time constants. The frequency deviation is divided into multiple fuzzy subsets according to the direction and amplitude of fluctuation; the frequency change rate is divided into multiple fuzzy subsets according to the rate and direction of change; the flywheel charge state is divided into multiple fuzzy subsets according to the charge and discharge margin; and the energy storage safety state characteristic quantity and the urgency of power reduction are divided into multiple fuzzy subsets according to safety, early warning, and urgency, respectively. Based on three-level priority collaborative reasoning: when the urgency of reducing output exceeds the mandatory threshold, the ramp correction coefficient shall not be lower than the minimum value required for safe reduction output; When the frequency deviation and the frequency change rate both worsen in the same direction, increase the flywheel compensation coefficient and slow down the power reduction ramp rate. After the frequency deviation returns to the dead zone, the flywheel compensation coefficient is reduced and the filter time constant is increased to restore the flywheel's state of charge to the target range. The inference results are defuzzified to obtain the ramp correction coefficient, flywheel compensation coefficient, and filter time constant.

5. The flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination as described in claim 4, characterized in that: The energy storage safety state characteristic quantities are jointly determined by the gas storage tank pressure state quantity, the heat storage tank heat state quantity and the expander inlet temperature state quantity. Each state quantity is normalized according to its own safety range and then weighted and synthesized. The urgency of the reduced output force is determined by the smallest margin from the lower safety limit among the pressure state of the gas storage tank, the heat state of the heat storage tank, and the temperature state of the expander inlet. When the energy storage safety state characteristic quantity is lower than the safety lower limit, the compressed air energy storage is marked as a forced output reduction state, and the minimum allowable power reduction ramp rate is determined according to the urgency of the output reduction. The compressed air energy storage output shall not be forcibly maintained due to frequency requirements.

6. The flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination as described in claim 5, characterized in that: The transient reference power is sent to the compressed air energy storage, and the flywheel energy storage performs a charge and discharge response according to the rapid compensation power command, including adjusting the mass flow rate of the expander inlet according to the transient reference power, rapidly correcting the valve position according to the shaft speed deviation, and adjusting the flow rate of the heat storage medium according to the expander inlet temperature. When the pressure of the gas storage tank, the temperature of the heat storage tank, the inlet temperature of the expander, or the speed of the shaft system exceeds the limit, the operation based on the transient reference power will be stopped, and the operation will be switched to protection derating. In case of overspeed or overpressure, unloading and venting will be performed. The flywheel motor torque command is generated based on the fast compensation power command, and then converted into a bidirectional converter current command through the inner current loop. The flywheel energy storage performs a fast charge and discharge response based on the current command.

7. The flywheel-compressed air hybrid energy storage primary frequency regulation control method based on fuzzy coordination as described in claim 6, characterized in that: During the power ramp-up and power recovery transient, the actual power of compressed air energy storage is constrained by the valve opening change rate and the mass flow rate at the expander inlet, lagging behind the total primary frequency regulation power command of hybrid energy storage. A ramp-up compensation command is issued to flywheel energy storage, and flywheel energy storage assumes the transient power deficit during the ramp-up lag period. As the actual power of compressed air energy storage gradually approaches the transient reference power, the compensation power command issued to flywheel energy storage is gradually reduced according to the slope limit until the compensation power returns to zero. After the frequency deviation at the grid connection point returns to the frequency regulation dead zone, a state of charge recovery command is sent to the flywheel energy storage. The flywheel energy storage then charges and discharges at low power to return the state of charge to the target range.

8. A fuzzy coordination-based flywheel-compressed air hybrid energy storage primary frequency regulation control system, based on the fuzzy coordination-based flywheel-compressed air hybrid energy storage primary frequency regulation control method according to any one of claims 1-7, characterized in that: It also includes, The feature characterization module collects grid connection point frequency, frequency change rate, actual active power of compressed air energy storage, target safe power of compressed air energy storage, allowable ramp rate, energy storage safety state characteristic quantities characterizing the safety state of compressed air energy storage, and flywheel state of charge. The identification module identifies the current transient state type of compressed air energy storage based on the target safe power, actual active power, and energy storage safety state characteristics of the compressed air energy storage. The calculation module calculates the total primary frequency regulation power command for hybrid energy storage based on the grid connection point frequency and frequency change rate. It performs fuzzy inference with the grid connection point frequency deviation, frequency change rate, flywheel state of charge, energy storage safety state characteristics and power reduction urgency as inputs, and outputs the ramp correction coefficient, flywheel compensation coefficient and filter time constant. The issuing module generates a compressed air energy storage transient reference power that meets the equipment safety boundary based on the transient type, ramp correction coefficient and allowable ramp rate. It calculates the transient power deficit based on the total primary frequency regulation power command of the hybrid energy storage and the compressed air energy storage transient reference power. When the flywheel charge state is within the safe range, it issues a fast compensation power command to the flywheel energy storage. The frequency modulation control module sends the transient reference power to the compressed air energy storage, and the flywheel energy storage executes the charging and discharging response according to the fast compensation power command, thus completing the first frequency modulation control for the transient process of compressed air energy storage.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency modulation control method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the fuzzy coordinated flywheel-compressed air hybrid energy storage primary frequency modulation control method according to any one of claims 1-7.

Images