Cooperative frequency modulation control method for flywheel energy storage auxiliary thermal power generating unit

Abstract

The invention relates to the technical field of power systems, and discloses a flywheel energy storage assisted thermal power generating unit collaborative frequency modulation control method, which comprises the following steps: extracting dominant dynamic characteristics based on state matrix eigenvalue analysis through a joint dynamic model, and setting layered optimization time granularity according to the dominant dynamic characteristics; aiming at the difference between the thermal power slow dynamic characteristic and the flywheel fast dynamic characteristic, optimization objective functions of a thermal power layer and a flywheel layer are respectively designed, robust consistency constraint is introduced, and multi-time scale optimization instruction iteration generation is realized through an asynchronous coordination algorithm. The system monitors the frequency change rate of a power grid in real time, dynamically adjusts virtual inertia parameters of the flywheel and generates dynamic compensation power, and finally fuses the coordinated reference instruction and the dynamic compensation amount to form an execution instruction. According to the scheme, the frequency dynamic stability in the new energy power grid frequency modulation process can be remarkably improved, and meanwhile, the frequency modulation equipment loss and the sustainable operation capability of the energy storage system are balanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems, and in particular relates to a coordinated frequency regulation control method for a flywheel energy storage-assisted thermal power generation unit. Background Art

[0002] As the penetration rate of new energy sources gradually increases, the problem of grid frequency stability becomes more serious. There is an urgent need to improve dynamic response capabilities and inertial support through coordinated frequency regulation of thermal power and energy storage to avoid the risk of large-scale power outages caused by frequency collapse.

[0003] Traditional coordination schemes often use fixed-proportion allocation or simple superposition control, which does not fully consider the dynamic differences between thermal power and energy storage on a time scale. This leads to conflicts in the power instructions of slow-dynamic units and fast-dynamic energy storage across the time dimension, which not only reduces the frequency regulation accuracy but also increases the risk of control oscillation. In addition, existing methods lack adaptability to the dynamic changes in system inertia. When the equivalent inertia decreases due to the increase in the penetration rate of new energy, the virtual inertia support strength cannot be adjusted in real time, which limits the frequency change rate suppression effect and the system's anti-disturbance capability. The energy storage charge state management strategy is also not deeply coupled with the frequency regulation requirements. Excessive charging and discharging accelerates equipment aging and restricts the sustainable regulation capability of energy storage.

[0004] Therefore, there is an urgent need to develop a flywheel energy storage-assisted coordinated frequency regulation control method for thermal power units, which can significantly improve the dynamic stability of the frequency during the frequency regulation process of the new energy power grid, while balancing the loss of the frequency regulation equipment and the sustainable operation capability of the energy storage system. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a flywheel energy storage-assisted coordinated frequency regulation control method for thermal power units, which can significantly improve the dynamic frequency stability during the frequency regulation process of the new energy power grid, while balancing the loss of frequency regulation equipment and the sustainable operation capability of the energy storage system.

[0006] The present invention provides a coordinated frequency regulation control method for a flywheel energy storage-assisted thermal power unit, the method comprising the following steps: S1. Construct a joint dynamic model of the thermal power unit and the flywheel energy storage, where the joint dynamic model includes the state equation of the thermal power unit and the state equation of the flywheel energy storage; S2. Extract the dominant dynamic characteristics of the thermal power unit and the flywheel energy storage based on the state matrix eigenvalues ​​of the joint dynamic model; S3. According to the time constant of the dominant dynamic characteristics of the thermal power unit, the first cycle time granularity of the thermal power layer optimization is set, and according to the time constant of the dominant dynamic characteristics of the flywheel energy storage, the second cycle time granularity of the flywheel layer optimization is set; S4. Constructing an optimization objective function for the thermal power layer according to the first cycle time granularity, and constructing an optimization objective function for the flywheel layer according to the second cycle time granularity; S5. Define robust consistency constraints for the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer, iteratively optimize the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer through an asynchronous coordination algorithm, and output the coordinated thermal power reference instruction and flywheel reference instruction; S6. Real-time monitoring of the frequency change rate of the power system, dynamic adjustment of the virtual inertia parameters of the flywheel energy storage according to the frequency change rate, and generation of flywheel dynamic compensation power matching the virtual inertia parameters; S7. Obtain a thermal power unit execution instruction according to the coordinated thermal power reference instruction and the thermal power unit control input; obtain a flywheel energy storage execution instruction according to the coordinated flywheel reference instruction and the flywheel dynamic compensation power.

[0007] Furthermore, in S1, the expressions of the state equation of the thermal power unit and the state equation of the flywheel energy storage are as follows: ; in, Indicates the rate of change of the output power of the thermal power unit over time, T th represents the time constant of the thermal power unit, x1(t) represents the output power of the thermal power unit at time t, K th Indicates the gain coefficient of thermal power unit, u th (t) represents the control input of the thermal power unit at time t, d1(t) represents the first renewable energy disturbance term at time t, and t represents time; The expression of the flywheel energy storage state equation is as follows: ; in, Indicates the rate of change of flywheel energy storage output power over time, T f represents the flywheel energy storage time constant, x2(t) represents the flywheel energy storage output power at time t, K f Indicates the flywheel energy storage gain coefficient, u f (t) represents the flywheel energy storage control input at time t, and d2(t) represents the second renewable energy disturbance term at time t.

[0008] Furthermore, in S3, the first cycle time granularity is a preset multiple of the time constant of the thermal power unit, and the second cycle time granularity is a preset multiple of the flywheel energy storage time constant.

[0009] Furthermore, in S4, the optimization objective function of the thermal power layer is expressed as follows: ; Among them, n represents the nth first time window, the length of the first time window is the first cycle time granularity, u th (n) represents the optimization instruction of the thermal power layer in the first time window of n, u th (n-1) represents the optimization instruction of the thermal power layer in the n-1th first time window, N represents the total number of first time windows, represents the quadratic coefficient of the power generation cost of the thermal power unit, b represents the thermal power ramp penalty coefficient, ρ represents the coordination weight coefficient, and z(n) represents the coordination variable generated by the flywheel layer in the nth first time window.

[0010] Furthermore, in S4, the expression of the optimization objective function of the flywheel layer is as follows: ; Among them, m represents the mth second time window, the length of the second time window is the second cycle time granularity, u f (m) represents the optimization instruction of the flywheel layer in the mth second time window, M represents the total number of second time windows, β represents the flywheel energy storage loss coefficient, μ represents the SOC penalty coefficient, SOC(m) represents the flywheel energy storage charge state in the mth second time window, ρ represents the coordination weight coefficient, Represents the coordination variable generated by the thermal power layer in the mth second time window.

[0011] Furthermore, in S5, the robust consistency constraints of the optimization objective functions of the thermal power layer and the flywheel layer are defined as follows: ; Where M represents the total number of second time windows, m represents the mth second time window, and u f (m) represents the optimization instruction of the flywheel layer in the mth second time window, u th (n) represents the optimization instruction of the thermal power layer in the first time window of n, Δ max Indicates the maximum allowable power deviation.

[0012] Furthermore, in S5, the process of iteratively optimizing the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer through the asynchronous coordination algorithm also includes updating the coordination variables. The formula for updating the coordination variables is as follows: ; Where z represents the coordination variable generated by the flywheel layer or the coordination variable generated by the thermal power layer, z k+1 It represents the coordination variable generated by the flywheel layer or the thermal power layer at the k+1th iteration, k represents the number of iterations, It represents the optimization instruction of the thermal power layer in the nth first time window iteration k+1 times, M represents the total number of second time windows, ) represents the optimization instruction of the flywheel layer in the kth iteration of the mth second time window.

[0013] Furthermore, in S6, the dynamic adjustment rules of the virtual inertia parameters include: When the power system frequency change rate is greater than a preset threshold, the virtual inertia parameter is adjusted to a preset multiple of the virtual inertia base value; when the power system frequency change rate is less than or equal to the preset threshold, the virtual inertia parameter is adjusted to the virtual inertia base value.

[0014] Furthermore, in S6, the calculation formula of the flywheel dynamic compensation power is as follows: ; in, represents the flywheel dynamic compensation power at time t, represents the compensation gain, Indicates the rate of change of frequency.

[0015] Furthermore, S7 specifically includes: performing dead-zone processing on the coordinated thermal power reference instruction and the thermal power unit control input to obtain the thermal power unit execution instruction; The coordinated flywheel reference instruction is superimposed on the flywheel dynamic compensation power and then the state of charge safety limit processing is performed to obtain the flywheel energy storage execution instruction.

[0016] The embodiments of the present invention have the following technical effects: This solution constructs a joint dynamic model of thermal power and flywheel energy storage, characterizes the slow and fast dynamic characteristics of the two based on state space separation, and uses a hierarchical optimization framework to design control objectives at minute and second time granularities, respectively. Combined with an asynchronous coordination algorithm, it achieves consistent matching of cross-scale power commands, resolving the control conflict problem caused by dynamic response mismatch. A virtual inertia segmented adjustment mechanism is introduced on the flywheel side to dynamically improve the inertial support strength based on the real-time frequency change rate. By integrating compensatory power generation with energy storage output, the system's adaptability to inertia-missing scenarios is enhanced. At the same time, energy storage state of charge safety constraints and life loss cost items are embedded in the optimization objectives, and the output boundary is adjusted in combination with a dynamic scaling factor, achieving a coordinated balance between frequency regulation requirements and energy storage health status. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1This is a flow chart of a coordinated frequency regulation control method for a flywheel energy storage-assisted thermal power unit provided by an embodiment of the present invention; Figure 2 is a schematic diagram of iteratively updating a coordination variable provided by an embodiment of the present invention; Figure 3 This is a comparison diagram of the thermal power-flywheel synergy and independent frequency regulation effects provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0020] The embodiment of the present invention provides a coordinated frequency regulation control method for a flywheel energy storage-assisted thermal power generation unit. Figure 1 This is a flow chart of a coordinated frequency regulation control method for a flywheel energy storage-assisted thermal power unit provided by an embodiment of the present invention. Figure 1 , the method comprises the following steps: S1. Construct a joint dynamic model of the thermal power unit and the flywheel energy storage. The joint dynamic model includes the state equation of the thermal power unit and the state equation of the flywheel energy storage.

[0021] In some embodiments, the state equation of the thermal power unit and the state equation of the flywheel energy storage are expressed as follows: ; in, Indicates the rate of change of the output power of the thermal power unit over time, T th represents the time constant of the thermal power unit. For example, the typical value is 30s. x1(t) represents the output power of the thermal power unit at time t. K th Indicates the gain coefficient of thermal power unit, u th (t) represents the control input of the thermal power unit at time t, d1(t) represents the first renewable energy disturbance term at time t, and t represents time; The expression of the flywheel energy storage state equation is as follows: ; in, Indicates the rate of change of flywheel energy storage output power over time, T f represents the flywheel energy storage time constant, for example, the typical value is 0.5s, x2(t) represents the flywheel energy storage output power at time t, K f Indicates the flywheel energy storage gain coefficient, u f(t) represents the flywheel energy storage control input at time t, and d2(t) represents the second renewable energy disturbance term at time t.

[0022] S2. Based on the state matrix eigenvalues ​​of the joint dynamic model, the dominant dynamic characteristics of the thermal power unit and the flywheel energy storage are extracted.

[0023] ; Among them, A represents the state matrix, according to which the dominant dynamic characteristic λ of the thermal power unit can be obtained th = , flywheel energy storage dominates the dynamic characteristics λ f = .

[0024] S3. According to the time constant of the dominant dynamic characteristics of the thermal power unit, the first cycle time granularity of the thermal power layer optimization is set, and according to the time constant of the dominant dynamic characteristics of the flywheel energy storage, the second cycle time granularity of the flywheel layer optimization is set.

[0025] In some embodiments, the first cycle time granularity is a preset multiple of the time constant of the thermal power unit, and the second cycle time granularity is a preset multiple of the time constant of the flywheel energy storage. For example, the first cycle time granularity can be set to 2T th , i.e. 60s, the second cycle time granularity can be set to 2T f , that is 1s.

[0026] S4. Construct an optimization objective function for the thermal power layer according to the first cycle time granularity, and construct an optimization objective function for the flywheel layer according to the second cycle time granularity.

[0027] In some embodiments, the optimization objective function of the thermal power layer is expressed as follows: ; Among them, n represents the nth first time window, the length of the first time window is the first cycle time granularity, u th (n) represents the optimization instruction of the thermal power layer in the first time window of n, u th (n-1) represents the optimization instruction of the thermal power layer in the n-1th first time window, N represents the total number of first time windows, represents the quadratic coefficient of the power generation cost of the thermal power unit, which can be set to 0.005 for example, and b represents the thermal power ramp penalty coefficient, which satisfies , exemplarily, it can be set to 0.1, ρ represents the coordination weight coefficient, exemplarily, it can be set to 0.2, and z(n) represents the coordination variable generated by the flywheel layer in the nth first time window. Thermal power units have slow response speeds but large capacity and low cost. Introducing quadratic terms and ramping penalties into the optimization objective reduces frequent thermal power adjustments, lowering wear and fuel consumption.

[0028] In some embodiments, the optimization objective function of the flywheel layer is expressed as follows: ; Among them, m represents the mth second time window, the length of the second time window is the second cycle time granularity, u f (m) represents the optimization instruction of the flywheel layer in the mth second time window, M represents the total number of second time windows, M is the ratio of the first cycle time granularity to the second cycle time granularity, for example, when the first cycle time granularity is 60s and the second cycle time granularity is 1s, M=60, β represents the flywheel energy storage loss coefficient, satisfying , for example, it can be set to 0.01, μ represents the SOC penalty coefficient, which is used to quantify the weight parameter of the flywheel energy storage state of charge (SOC(m)) deviating from the nominal value (0.5). For example, it can be set to 100, SOC(m) represents the flywheel energy storage state of charge in the mth second time window, and the safety range of SOC is [0.2, 0.8]. ρ represents the coordination weight coefficient. represents the coordination variable generated by the thermal power layer in the mth second time window. Flywheels have fast response but small capacity and are sensitive to cycle life. The SOC penalty term limits the SOC to a safe range (0.2-0.8) to extend the energy storage life.

[0029] S5. Define the robust consistency constraints of the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer, iteratively optimize the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer through the asynchronous coordination algorithm, and output the coordinated thermal power reference instruction and flywheel reference instruction.

[0030] In some embodiments, the robust consistency constraints are as follows: ; Where M represents the total number of second time windows, m represents the mth second time window, and u f (m) represents the optimization instruction of the flywheel layer in the mth second time window, u th (n) represents the optimization instruction of the thermal power layer in the first time window of n, Δ max The maximum allowable power deviation can be set based on actual conditions. In this example, it is set to 3% of the system's rated power. The robust consistency constraint enforces consistency between thermal power and flywheel output over long timescales, preventing cumulative deviations due to timescale differences (e.g., thermal power failing to catch up after a short-term flywheel overcompensation). By limiting power deviation, secondary frequency fluctuations caused by uncoordinated thermal power and flywheel output during frequency regulation can be avoided.

[0031] In some embodiments, the process of iteratively optimizing the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer using the asynchronous coordination algorithm also includes updating the coordination variables. The formula for updating the coordination variables is as follows: ; Where z represents the coordination variable generated by the flywheel layer or the coordination variable generated by the thermal power layer, z k+1 It represents the coordination variable generated by the flywheel layer or the thermal power layer at the k+1th iteration, k represents the number of iterations, It represents the optimization instruction of the thermal power layer in the nth first time window iteration k+1 times, M represents the total number of second time windows, ) represents the optimization instruction of the flywheel layer during the kth iteration of the mth second time window. The coordination variable z gradually approaches the global optimum through asynchronous fusion, taking into account both the economic efficiency of thermal power generation and the dynamic performance of the flywheel.

[0032] In some embodiments, the asynchronous coordination algorithm is an alternating direction multiplier method, which uses the alternating direction multiplier method to perform hierarchical iterations on the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer. For example, the optimization objective function of the thermal power layer is executed once every 60 seconds, and the optimization objective function of the flywheel layer is executed once every 1 second. The coordination variables are updated at the same time in each iteration. Figure 2 This is a schematic diagram of an iterative update of a coordination variable provided by an embodiment of the present invention, see Figure 2 The vertical axis represents the absolute value of the deviation between the control input of the thermal power unit or the control input of the flywheel energy storage and the coordination variable, which represents the degree of deviation between the control instruction and the coordination target. It can be seen from the figure that the deviation between the thermal power unit and the flywheel energy storage gradually reaches synchronous convergence during the iteration process, indicating that the two have reached an agreement under the global goal, solving the cross-time scale coordination problem of the slow dynamics of thermal power and the fast dynamics of the flywheel, and can effectively coordinate the control quantities of thermal power and flywheel to meet the consistency requirements of frequency regulation.

[0033] S6. Real-time monitoring of the frequency change rate of the power system, dynamic adjustment of the virtual inertia parameters of the flywheel energy storage according to the frequency change rate, and generation of flywheel dynamic compensation power matching the virtual inertia parameters.

[0034] In some embodiments, the dynamic adjustment rules of the virtual inertia parameters include: When the power system frequency change rate exceeds a preset threshold, the virtual inertia parameter is adjusted to a preset multiple of the virtual inertia base value. When the power system frequency change rate is less than or equal to the preset threshold, the virtual inertia parameter is adjusted to the virtual inertia base value. The virtual inertia parameter is used to increase system inertia and suppress sudden frequency changes. Under normal operating conditions, the base inertia is maintained and increased only in emergency conditions to prevent the flywheel from operating under continuous high loads.

[0035] For example, assuming that the preset threshold is 0.1 Hz / s and the preset multiple is 1.5, the expression of the virtual inertia parameter is as follows: ; Among them, H f (t) represents the virtual inertia parameter, H base Indicates the virtual inertia base value, which can be set to 0.5 for example. Indicates the rate of change of frequency, obtained through real-time measurement.

[0036] In some embodiments, the calculation formula of the flywheel dynamic compensation power is as follows: ; ; in, represents the flywheel dynamic compensation power at time t, represents the compensation gain, S represents the system base capacity, Represents the rate of change of frequency. The flywheel's dynamic compensation power is directly related to the rate of change of frequency. The flywheel can provide reverse power in milliseconds (e.g., releasing energy when the frequency drops suddenly), quickly smoothing out disturbances.

[0037] S7. Obtain a thermal power unit execution instruction according to the coordinated thermal power reference instruction and the thermal power unit control input; obtain a flywheel energy storage execution instruction according to the coordinated flywheel reference instruction and the flywheel dynamic compensation power.

[0038] Specifically include: The coordinated thermal power reference instruction and the thermal power unit control input are dead-zone processed to obtain the thermal power unit execution instruction. The calculation formula is as follows: ; in, Indicates that the thermal power unit executes the instruction. represents the final thermal power reference instruction output in step S5, represents the actual thermal power unit input, and DeadZone represents the dead zone function, which is used to suppress small fluctuations within the range of ±2% to avoid frequent adjustments of the thermal power unit due to noise or measurement errors.

[0039] The coordinated flywheel reference command is superimposed on the flywheel dynamic compensation power and then subjected to state of charge safety limiting processing to obtain the flywheel energy storage execution command. The calculation formula is as follows: ; ; in, Indicates the flywheel energy storage execution instruction, The final flywheel reference command outputted in step S5, SOCt Indicates the safety scaling factor. When the SOC approaches the lower limit, the output is automatically reduced to prevent over-discharge.

[0040] Frequency regulation control is performed on the thermal power unit and the flywheel energy storage device respectively according to the thermal power unit execution instruction and the flywheel energy storage execution instruction.

[0041] Figure 3 This is a comparison diagram of the thermal power-flywheel synergy and independent frequency regulation effects provided by an embodiment of the present invention, see Figure 3 The absolute value of the frequency deviation in this coordinated frequency regulation scheme (solid green line) is significantly lower than that in the independent frequency regulation scheme throughout the entire process. Independent thermal power generation (dashed red line) suffers from slow dynamics: initial response lag (maximum deviation between 0 and 10 seconds), and low-frequency fluctuations (0.2-0.4 Hz) persist during the steady-state phase due to mechanical inertia. Independent flywheel frequency regulation (dashed blue line) is subject to capacity limitations: initial rapid response (with a rapid decrease in deviation between 10 and 20 seconds), but later on, due to insufficient energy storage capacity (SOC limitation), the deviation rebounds to 0.3 Hz. As shown in the figure, the coordinated frequency regulation curve is significantly smoother than the independent scheme, and coordinated frequency regulation suppresses secondary frequency drops caused by the slow dynamics of thermal power generation, thus avoiding the risk of system instability.

[0042] This solution constructs a joint dynamic model of thermal power and flywheel energy storage, characterizes the slow and fast dynamic characteristics of the two based on state space separation, and uses a hierarchical optimization framework to design control objectives at minute and second time granularities, respectively. Combined with an asynchronous coordination algorithm, it achieves consistent matching of cross-scale power commands, resolving the control conflict problem caused by dynamic response mismatch. A virtual inertia segmented adjustment mechanism is introduced on the flywheel side to dynamically improve the inertial support strength based on the real-time frequency change rate. By integrating compensatory power generation with energy storage output, the system's adaptability to inertia-missing scenarios is enhanced. At the same time, energy storage state of charge safety constraints and life loss cost items are embedded in the optimization objectives, and the output boundary is adjusted in combination with a dynamic scaling factor, achieving a coordinated balance between frequency regulation requirements and energy storage health status.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A flywheel energy storage assisted thermal power unit coordinated frequency modulation control method, characterized in that: The method comprises the following steps: S1. Constructing a joint dynamic model of a thermal power unit and a flywheel energy storage, wherein the joint dynamic model includes a state equation of the thermal power unit and a state equation of the flywheel energy storage; S2. extracting the dominant dynamic characteristics of the thermal power unit and the dominant dynamic characteristics of the flywheel energy storage based on the state matrix eigenvalues ​​of the joint dynamic model; S3. Setting a first cycle time granularity for thermal power layer optimization according to the time constant of the dominant dynamic characteristics of the thermal power unit, and setting a second cycle time granularity for flywheel layer optimization according to the time constant of the dominant dynamic characteristics of the flywheel energy storage; S4. Constructing an optimization objective function for the thermal power layer according to the first cycle time granularity, and constructing an optimization objective function for the flywheel layer according to the second cycle time granularity; S5. Define robust consistency constraints for the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer, iteratively optimize the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer through an asynchronous coordination algorithm, and output coordinated thermal power reference instructions and flywheel reference instructions; S6. Real-time monitoring of the frequency change rate of the power system, dynamic adjustment of the virtual inertia parameter of the flywheel energy storage according to the frequency change rate, and generation of a flywheel dynamic compensation power matching the virtual inertia parameter; S7. Obtaining a thermal power unit execution instruction according to the coordinated thermal power reference instruction and the thermal power unit control input; obtaining a flywheel energy storage execution instruction according to the coordinated flywheel reference instruction and the flywheel dynamic compensation power.

2. A coordinated frequency modulation control method for a flywheel energy storage-assisted thermal power unit according to claim 1, characterized in that: In S1, the expressions of the thermal power unit state equation and the flywheel energy storage state equation are as follows: ； in, Indicates the rate of change of the output power of the thermal power unit over time, T th represents the time constant of the thermal power unit, x1(t) represents the output power of the thermal power unit at time t, K th Indicates the gain coefficient of thermal power unit, u th (t) represents the control input of the thermal power unit at time t, d1(t) represents the first renewable energy disturbance term at time t, and t represents time; The expression of the flywheel energy storage state equation is as follows: ； in, Indicates the rate of change of flywheel energy storage output power over time, T f represents the flywheel energy storage time constant, x2(t) represents the flywheel energy storage output power at time t, K f Indicates the flywheel energy storage gain coefficient, u f (t) represents the flywheel energy storage control input at time t, and d2(t) represents the second renewable energy disturbance term at time t.

3. The coordinated frequency modulation control method for a flywheel energy storage-assisted thermal power unit according to claim 2, characterized in that: In S3, the first cycle time granularity is a preset multiple of the time constant of the thermal power generation unit, and the second cycle time granularity is a preset multiple of the flywheel energy storage time constant.

4. A coordinated frequency modulation control method for a flywheel energy storage-assisted thermal power unit according to claim 3, characterized in that: In S4, the optimization objective function of the thermal power layer is expressed as follows: ； Among them, n represents the nth first time window, the length of the first time window is the first cycle time granularity, u th (n) represents the optimization instruction of the thermal power layer in the first time window of n, u th (n-1) represents the optimization instruction of the thermal power layer in the n-1th first time window, N represents the total number of first time windows, represents the quadratic coefficient of the power generation cost of the thermal power unit, b represents the thermal power ramp penalty coefficient, ρ represents the coordination weight coefficient, and z(n) represents the coordination variable generated by the flywheel layer in the nth first time window.

5. The coordinated frequency modulation control method for a flywheel energy storage-assisted thermal power unit according to claim 3, characterized in that: In S4, the expression of the optimization objective function of the flywheel layer is as follows: ； Among them, m represents the mth second time window, the length of the second time window is the second cycle time granularity, u f (m) represents the optimization instruction of the flywheel layer in the mth second time window, M represents the total number of second time windows, β represents the flywheel energy storage loss coefficient, μ represents the SOC penalty coefficient, SOC(m) represents the flywheel energy storage charge state in the mth second time window, ρ represents the coordination weight coefficient, Represents the coordination variable generated by the thermal power layer in the mth second time window.

6. The coordinated frequency modulation control method for a flywheel energy storage-assisted thermal power unit according to claim 1, characterized in that: In S5, the robust consistency constraints of the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer are defined as follows: ； Where M represents the total number of second time windows, m represents the mth second time window, and u f (m) represents the optimization instruction of the flywheel layer in the mth second time window, u th (n) represents the optimization instruction of the thermal power layer in the first time window of n, Δ max Indicates the maximum allowable power deviation.

7. A coordinated frequency regulation control method for a flywheel energy storage-assisted thermal power unit according to claim 6, characterized in that: In S5, the process of iteratively optimizing the optimization objective function of the thermal power layer and the optimization objective function of the flywheel layer by the asynchronous coordination algorithm also includes updating the coordination variables. The formula for updating the coordination variables is as follows: ； Where z represents the coordination variable generated by the flywheel layer or the coordination variable generated by the thermal power layer, z k+1 It represents the coordination variable generated by the flywheel layer or the thermal power layer at the k+1th iteration, k represents the number of iterations, It represents the optimization instruction of the thermal power layer in the nth first time window iteration k+1 times, M represents the total number of second time windows, ) represents the optimization instruction of the flywheel layer in the kth iteration of the mth second time window.

8. The coordinated frequency modulation control method for a flywheel energy storage-assisted thermal power unit according to claim 1, characterized in that: In S6, the dynamic adjustment rules of the virtual inertia parameters include: When the power system frequency change rate is greater than a preset threshold, the virtual inertia parameter is adjusted to a preset multiple of the virtual inertia base value; when the power system frequency change rate is less than or equal to the preset threshold, the virtual inertia parameter is adjusted to the virtual inertia base value.

9. The coordinated frequency modulation control method for a flywheel energy storage-assisted thermal power unit according to claim 1, characterized in that: In S6, the calculation formula of the flywheel dynamic compensation power is as follows: ； in, represents the flywheel dynamic compensation power at time t, represents the compensation gain, Indicates the rate of change of frequency.

10. The coordinated frequency regulation control method for a flywheel energy storage-assisted thermal power unit according to claim 1, characterized in that: The S7 specifically includes: performing dead zone processing on the coordinated thermal power reference instruction and the thermal power unit control input to obtain the thermal power unit execution instruction; The coordinated flywheel reference instruction is superimposed on the flywheel dynamic compensation power and then subjected to state of charge safety limiting processing to obtain a flywheel energy storage execution instruction.

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