Dynamic load shedding and frequency regulation coordinated control method for grid-connected wind-storage system based on state of charge drive

Abstract

The present invention provides a method for coordinated control of dynamic load shedding and frequency regulation of a grid-connected wind-storage system driven by state of charge, comprising the following steps: Step 1: establishing a grid-connected model of a doubly-fed wind turbine generator, and constructing a wind-storage combined system in combination with an energy storage system; Step 2: designing a control strategy for the wind-storage combined system based on the wind-storage combined system; Step 3: designing a wind turbine frequency regulation control strategy based on the wind-storage combined system control strategy; Step 4: designing an adaptive dynamic load shedding strategy for the wind-storage system in combination with the state of charge based on the wind turbine frequency regulation control strategy; The present invention introduces an adaptive SOC adjustment coefficient to achieve dynamic coordination of the frequency support capability of the wind-storage system while ensuring the safety and efficiency of wind turbine operation.

Description

Technical Field

[0001] The present invention relates to the field of power system control technology, and in particular to a method for coordinated control of dynamic load reduction and frequency regulation of a grid-connected wind-storage system driven by state of charge. Background Art

[0002] As wind power penetration continues to increase, its impact on power system frequency stability is becoming increasingly prominent. As a typical non-inertia power source, traditional wind turbines struggle to proactively respond to system frequency disturbances during grid-connected operation, impacting the response speed and power support capabilities of the primary frequency regulation process. To address this, grid-connected wind power technology has emerged. By introducing a virtual synchronous control mechanism, this technology imbues the wind turbine's power electronics interface with virtual inertia and damping characteristics, enabling it to achieve frequency response capabilities similar to synchronous generators.

[0003] Existing grid-connected wind turbine frequency regulation methods primarily include rotor kinetic energy release and power load shedding. The former releases mechanical kinetic energy by adjusting the rotational speed to support short-term frequency response, but is limited by wind speed and rotational inertia, making sustained output difficult. The latter reduces turbine active power output to reserve frequency regulation capacity, suitable for medium- and long-term frequency regulation. However, fixed load shedding strategies can cause frequency regulation capabilities to become disconnected from the actual system state, resulting in wasted reserve capacity or insufficient frequency regulation capability. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for coordinated control of dynamic load reduction and frequency regulation of a grid-connected wind-storage system driven by state of charge, so as to at least solve the above problems.

[0005] The technical solution adopted in the present invention is as follows:

[0006] The method for coordinated control of dynamic load shedding and frequency regulation of a grid-connected wind-storage system driven by state of charge includes the following steps:

[0007] Step 1: Establish a grid-connected model for a doubly-fed wind turbine generator and build a wind-storage combined system;

[0008] Step 2: Design the control strategy of the wind-storage combined system;

[0009] Step 3: Design the wind turbine frequency regulation control strategy based on the wind-storage combined system control strategy;

[0010] Step 4: Based on the wind turbine frequency control strategy and combined with the state of charge, design an adaptive dynamic load reduction strategy for the wind-storage system.

[0011] Furthermore, step 1 is specifically as follows:

[0012] A mathematical model of a doubly-fed wind turbine generator set is established. The rotor-side converter adopts VSG outer-loop control and voltage-current inner-loop control. The grid-side converter adopts DC voltage control to maintain the stability of the system DC side voltage. The energy storage system is connected to the DFIG DC bus through a bidirectional DC / DC converter. The energy storage system adopts virtual droop control. The rotor-side converter controls the target operating state of the doubly-fed wind turbine generator set through the maximum power tracking control module, and combines VSG control to dynamically control the output energy.

[0013] Furthermore, step 2 is specifically as follows:

[0014] The rotor-side converter adopts VSG control. Based on the virtual phase angle and voltage amplitude generated by VSG control, the rotor voltage is generated by voltage and current dual closed-loop control, and the active power and reactive power on the stator side are decoupled.

[0015] Maximum power tracking uses wind speed, output active power of the doubly-fed wind turbine and rotor speed as input parameters, calculates the active power reference value in real time, and uses the active power reference value as the input power command of the VSG to adjust the output power of the doubly-fed wind turbine;

[0016] The capacitor energy storage system adopts virtual droop control to dynamically adjust the active power reference values ​​of the wind turbine and energy storage so that their output power changes in coordination.

[0017] Furthermore, step 3 includes the following steps:

[0018] Step 31: Detect the grid frequency deviation and change rate in real time, and calculate the total power change required to be provided by the doubly-fed wind turbine generator set;

[0019] Step 32: When the wind turbine is in a load-reduced overspeed operation state, the doubly-fed wind turbine generator system reduces the wind energy utilization coefficient by increasing the tip speed ratio, outputs suboptimal power, and reserves frequency regulation standby capacity;

[0020] Step 33: Based on the current rotor speed and load reduction level, the reserved frequency regulation capacity is calculated as the limit frequency regulation power. The actual frequency regulation power is controlled to be less than or equal to the limit frequency regulation power to ensure that the rotor speed does not fall below the optimal speed.

[0021] Step 34: Adjust the output electromagnetic power of the doubly-fed wind turbine generator set according to the total power variation. When the frequency drops, the power is increased from the suboptimal power to release the rotor kinetic energy. When the frequency rises again, the power is reduced to absorb energy and restore the rotor speed.

[0022] Step 35: After the grid frequency stabilizes, the power reference value returns to the initial load reduction power, restoring the initial frequency regulation reserve capacity to ensure subsequent frequency regulation capabilities.

[0023] Furthermore, the total power change calculation formula in step 31 is:

[0024]

[0025] in, , indicating that the active power reference value controlled by VSG is determined by the wind turbine MPPT output power and FM output power composition; Indicates the primary frequency modulation coefficient; Indicates the grid angular frequency deviation, Indicates the rate of change of grid angular frequency deviation; represents the damping coefficient; represents the moment of inertia; Indicates the total power change;

[0026] In step 32, the wind turbine reduces the wind energy utilization coefficient by increasing the tip speed ratio, and the output suboptimal power calculation formula is:

[0027]

[0028] in, Indicates load shedding The suboptimal power obtained by the wind turbine is Indicates the initial load shedding level; represents the wind energy utilization coefficient in the load-reduced state, and , represents the optimal wind energy utilization coefficient; Indicates the air density; represents the fan swept area; Indicates the fan rotor speed; Indicates the fan blade radius; Indicates the tip speed ratio in the unloaded state; represents the suboptimal power proportionality factor;

[0029] The calculation formula for the limit frequency modulation power in step 33 is:

[0030]

[0031] in, Indicates the fan's maximum frequency modulation power; represents the maximum power tracking coefficient; represents the optimal tip speed ratio;

[0032] Furthermore, step 4 is specifically as follows:

[0033] The active power reduction ratio of the suboptimal power relative to the maximum power during load shedding is calculated. In the process of providing spare capacity by the wind turbine frequency regulation control strategy, the SOC adjustment coefficient is introduced to establish a dynamic SOC adjustment mechanism. The load shedding ratio of the doubly fed wind turbine generator set is dynamically adjusted by real-time calculation of the SOC adjustment coefficient.

[0034] Furthermore, the active power reduction ratio of the suboptimal power to the maximum power during load reduction is calculated as follows:

[0035]

[0036] in, Indicates the active power load reduction ratio of suboptimal power relative to maximum power; represents suboptimal power; Indicates maximum power;

[0037] The SOC adjustment coefficient is introduced to establish the SOC dynamic adjustment mechanism. The calculation formula is:

[0038]

[0039] in, Indicates the power after dynamic adjustment; Indicates the SOC adjustment coefficient.

[0040] Furthermore, the SOC adjustment coefficient uses a piecewise logistic function according to the range of the energy storage SOC, and the calculation formula is:

[0041]

[0042] in, Indicates the curve change rate factor; Indicates the initial power of energy storage; Indicates the maximum output power of energy storage; Represent the minimum and maximum values ​​of SOC respectively; is an intermediate parameter, whose value is .

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention provides a method for coordinated control of dynamic load shedding and frequency regulation of a grid-type wind-storage system driven by state of charge. A coordinated mechanism of VSG control and virtual droop control is designed, fully considering the rotor kinetic energy release capability of the doubly-fed wind turbine and the output capability of the energy storage system. By introducing a dynamic load shedding adjustment mechanism driven by SOC, the optimal distribution of wind-storage combined frequency regulation power is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only preferred embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 It is a schematic flow chart of the method provided by the present invention;

[0047] Figure 2 This is a schematic diagram of the structure of the doubly-fed wind turbine control model provided by the present invention;

[0048] Figure 3 This is a schematic diagram of the VSG outer loop control structure provided by the present invention;

[0049] Figure 4 It is a schematic diagram of the load shedding control principle of the doubly-fed wind turbine generator set provided by the present invention. DETAILED DESCRIPTION

[0050] The principles and features of the present invention are described below with reference to the accompanying drawings. The enumerated embodiments are only used to explain the present invention and are not used to limit the scope of the present invention.

[0051] Reference Figure 1 and Figure 2 The present invention provides a method for coordinated control of dynamic load shedding and frequency regulation of a grid-connected wind-storage system based on state of charge drive, comprising the following steps:

[0052] Step 1: Establish a grid-connected model for a doubly-fed wind turbine generator and build a wind-storage combined system, specifically:

[0053] A mathematical model of a doubly fed wind turbine generator is established. The rotor-side converter adopts VSG outer loop control and voltage-current inner loop control. The grid-side converter adopts DC voltage control to maintain the stability of the system DC side voltage. The energy storage system is connected to the DFIG DC bus through a bidirectional DC / DC converter. The energy storage system adopts virtual droop control. The rotor-side converter controls the target operating state of the doubly fed wind turbine generator set through the maximum power tracking control module, and combines VSG control to dynamically control the output energy.

[0054] Exemplarily, the transfer function of the system frequency characteristic model is:

[0055]

[0056] in, Indicates the system frequency deviation; Indicates the change in total active power of the system; represents the Laplace operator; represents the renewable energy penetration rate; represents the equivalent inertia time constant of the system; represents the equivalent damping coefficient of the system; Indicates the power change of the synchronous unit; Indicates the total power change of the system; Indicates the power change of the power supply; Indicates the load change.

[0057] Step 2: Design the control strategy for the wind-storage combined system, specifically:

[0058] The rotor-side converter adopts VSG control. Based on the virtual phase angle and voltage amplitude generated by VSG control, the rotor voltage is generated by voltage and current dual closed-loop control, and the active power and reactive power on the stator side are decoupled.

[0059] Maximum power tracking uses wind speed, output active power of the doubly-fed wind turbine and rotor speed as input parameters, calculates the active power reference value in real time, and uses the active power reference value as the input power command of the VSG to adjust the output power of the doubly-fed wind turbine;

[0060] The capacitor energy storage system adopts virtual droop control to dynamically adjust the active power reference values ​​of the wind turbine and energy storage so that their output power changes in coordination.

[0061] For example, according to Figure 3 The wind turbine uses VSG outer loop control and voltage-current inner loop control. VSG control calculates the synchronous angular frequency through active power deviation, adjusts the stator voltage amplitude through reactive power deviation, and generates stator voltage through vector synthesis. The VSG active and reactive power control equations are:

[0062]

[0063] in, Indicates the given active power reference value for maximum power point tracking; Indicates the actual output value of active power; and represents the inertia and damping coefficients; and Respectively represent the rated angular frequency and actual angular frequency values ​​of VSG; and Respectively represent the reactive power reference value and the reactive power actual output value; and Respectively represent the reactive loop ratio and integral coefficient; and Respectively represent the given reference voltage amplitude and output voltage amplitude; represents the Laplace operator.

[0064] According to the mathematical model of the doubly fed wind turbine generator, ignoring the dynamic process of the stator current, the control equation of the current inner loop can be obtained as follows:

[0065]

[0066] in, 、 、 、 Represent the current components and reference values ​​of the rotor d and q axes respectively; 、 denote the inductance of the rotor and stator respectively; 、 Respectively represent the proportional and integral coefficients of the current loop; 、 Represent the voltage output of the rotor d and q axes respectively; 、 They represent the current components of the stator d and q axes respectively; represents the Laplace operator; Indicates the actual angular frequency value;

[0067] Since the excitation current of the doubly fed wind turbine is mainly provided by the rotor current, the stator flux equation is substituted into the stator voltage equation and the stator current is ignored. When only the steady-state term is considered and the electromagnetic transient process is ignored, the following equation can be obtained:

[0068]

[0069] From the above equation, we can know that 、 and 、 They are linearly related, and the control equation of the voltage outer loop is:

[0070]

[0071] in, 、 Indicates the PI coefficient of the current loop; 、 、 、 Indicates the reference value and actual value of the d-axis and q-axis respectively.

[0072] Step 3: Based on the wind-storage combined system control strategy, design the wind turbine frequency regulation control strategy, which includes the following steps:

[0073] Step 31: Detect the grid frequency deviation and change rate in real time, and calculate the total power change required to be provided by the doubly-fed wind turbine generator set;

[0074] Step 32: When the wind turbine is in a load-reduced overspeed operation state, the doubly-fed wind turbine generator system reduces the wind energy utilization coefficient by increasing the tip speed ratio, outputs suboptimal power, and reserves frequency regulation standby capacity;

[0075] Step 33: Based on the current rotor speed and load reduction level, the reserved frequency regulation capacity is calculated as the limit frequency regulation power. The actual frequency regulation power is controlled to be less than or equal to the limit frequency regulation power to ensure that the rotor speed does not fall below the optimal speed.

[0076] Step 34: Adjust the output electromagnetic power of the doubly-fed wind turbine generator set according to the total power variation. When the frequency drops, the power is increased from the suboptimal power to release the rotor kinetic energy. When the frequency rises again, the power is reduced to absorb energy and restore the rotor speed.

[0077] Step 35: After the grid frequency stabilizes, the power reference value returns to the initial load reduction power, restoring the initial frequency regulation reserve capacity to ensure subsequent frequency regulation capabilities.

[0078] For example, for a VSG controlled wind turbine, the total power variation is Related to frequency deviation and frequency change rate. The total output power change of the grid-connected wind turbine with primary frequency modulation function is The expression is as follows:

[0079]

[0080] in, , indicating that the active power reference value controlled by VSG is determined by the wind turbine MPPT output power and FM output power composition; Indicates the primary frequency modulation coefficient; Indicates the grid angular frequency deviation, Indicates the rate of change of grid angular frequency deviation; represents the damping coefficient; represents the moment of inertia; Indicates the total power change;

[0081] In the MPPT operation area, the pitch angle of the doubly fed wind turbine Always , the tip speed ratio is defined as

[0082]

[0083] in: Indicates the fan rotation angular velocity; represents the blade radius; Indicates wind speed;

[0084] Maximum mechanical power captured by the fan It can be expressed as

[0085]

[0086] in, Indicates the air density; represents the wind energy conversion rate; represents the optimal tip speed ratio; Indicates the area swept by the fan; represents the pitch angle; Indicates the fan rotation angular velocity; represents the blade radius; Indicates wind speed; Indicates intermediate calculation variables;

[0087] The doubly fed wind turbine generator is based on the current rotor speed Determining the Maximum Power Point and use it as the active power reference value input of VSG

[0088]

[0089] in, 、 for:

[0090]

[0091] in, represents the power tracking coefficient; represents the number of generator stages; Indicates the gearbox transmission coefficient; Indicates the air density; represents the wind energy conversion rate; represents the blade radius; Indicates the maximum tip speed ratio;

[0092] Figure 4 The power-speed curves during the frequency modulation process of the wind turbine VSG control during a sudden system load increase are shown. Before frequency modulation, the DFIG was operating at overspeed load shedding point A. When the frequency dropped significantly, the electromagnetic power increased from point A to point B. Because the output power exceeded the wind turbine's mechanical power, the rotor decelerated to release kinetic energy, and the electromagnetic power subsequently dropped to point O (the same power as point A). Afterward, the speed began to recover, and the DFIG needed to absorb grid energy, further reducing the output power. Throughout this process, the electromagnetic power varied along the ABOCA path, actively supporting the system frequency through the coordinated response of kinetic energy release and reserve capacity.

[0093] Assume that the initial load reduction level of the wind turbine is , then the wind energy utilization coefficient under load reduction state is for:

[0094]

[0095] in, Indicates the maximum power factor;

[0096] It can be obtained that the load reduction hour:

[0097]

[0098] in, Indicates fan load reduction Tip speed ratio at ;

[0099] Substitute the above formula into In the middle, load reduction is obtained The load shedding power expression is:

[0100]

[0101] in, Indicates load shedding The suboptimal power obtained by the wind turbine is Indicates the initial load shedding level; represents the wind energy utilization coefficient in the load-reduced state, and , represents the optimal wind energy utilization coefficient; Indicates the air density; represents the fan swept area; Indicates the fan rotor speed; Indicates the fan blade radius; Indicates the tip speed ratio in the unloaded state; represents the suboptimal power proportionality factor;

[0102] The power relationship between the maximum power tracking point and the overspeed point can be expressed as:

[0103]

[0104] From the power relationship between the maximum power tracking point and the overspeed point, the relationship between the two points can be obtained:

[0105]

[0106] Substituting the above formula into the load reduction power expression, the limit frequency modulation power can be obtained:

[0107]

[0108] in, Indicates the fan's maximum frequency modulation power; represents the maximum power tracking coefficient; represents the optimal tip speed ratio;

[0109] Step 4: Based on the wind turbine frequency modulation control strategy and combined with the state of charge, design an adaptive dynamic load reduction strategy for the wind-storage system. Specifically:

[0110] The active power reduction ratio of the suboptimal power relative to the maximum power during load shedding is calculated. In the process of providing spare capacity by the wind turbine frequency regulation control strategy, the SOC adjustment coefficient is introduced to establish a dynamic SOC adjustment mechanism. The load shedding ratio of the doubly fed wind turbine generator set is dynamically adjusted by real-time calculation of the SOC adjustment coefficient.

[0111] The formula for calculating the active power reduction ratio of suboptimal power to maximum power during load reduction is:

[0112]

[0113] in, Indicates the active power load reduction ratio of suboptimal power relative to maximum power; represents suboptimal power; Indicates maximum power;

[0114] The SOC adjustment coefficient is introduced to establish the SOC dynamic adjustment mechanism. The calculation formula is:

[0115]

[0116] in, Indicates the power after dynamic adjustment; Indicates the SOC adjustment coefficient.

[0117] The SOC adjustment coefficient uses a piecewise logistic function according to the range of the energy storage SOC. The calculation formula is:

[0118]

[0119] in, Indicates the curve change rate factor; Indicates the initial power of energy storage; Indicates the maximum output power of energy storage; Represent the minimum and maximum values ​​of SOC respectively; is an intermediate parameter, whose value is .

[0120] For example, Table 1 is a comparison chart of the adaptive dynamic load reduction strategy, the MPPT control strategy, and the fixed load reduction control strategy:

[0121] Table 1 Comparison of frequency regulation of grid-connected wind turbines

[0122]

[0123] As shown in the figure, the adaptive dynamic load shedding strategy flexibly adjusts the load shedding level based on the energy storage SOC, ensuring the timing of frequency regulation and reducing wind curtailment costs. When the energy storage SOC is low, wind power assumes more frequency regulation power by increasing the load shedding rate, thereby reducing the depth of energy storage discharge. When the wind turbine speed drops to near the limit of 0.7 pu, to prevent a secondary frequency drop, the energy storage system supports the system frequency by increasing its active power. When this strategy is used, the final energy storage SOC is 0.352 pu, which is higher than the fixed load shedding strategy. This provides sufficient backup resources for subsequent frequency regulation and optimizes the frequency response capability of the wind-storage coordinated system.

[0124] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for coordinated control of dynamic load shedding and frequency regulation of a grid-connected wind-storage system driven by state of charge, characterized in that: The following steps are involved: Step 1: Establish a grid-connected model for a doubly-fed wind turbine generator and build a wind-storage combined system in combination with an energy storage system. Specifically: A mathematical model of a doubly-fed wind turbine generator is established. The rotor-side converter uses VSG outer-loop control and voltage-current inner-loop control. The grid-side converter uses DC voltage control to maintain DC-side voltage stability. The energy storage system is connected to the DFIG DC bus via a bidirectional DC / DC converter. The energy storage system uses virtual droop control. The rotor-side converter uses a maximum power point tracking control module to control the target operating state of the doubly-fed wind turbine generator set, and combines VSG control to dynamically control the output energy. Step 2: Design a control strategy for the wind-storage combined system based on the wind-storage combined system; Step 3: Design the wind turbine frequency regulation control strategy based on the wind-storage combined system control strategy; Step 4: Based on the wind turbine frequency modulation control strategy and combined with the state of charge, design an adaptive dynamic load reduction strategy for the wind-storage system. Specifically: The active power reduction ratio of the suboptimal power relative to the maximum power during load shedding is calculated. In the process of providing spare capacity by the wind turbine frequency regulation control strategy, the SOC adjustment coefficient is introduced to establish a dynamic SOC adjustment mechanism. The load shedding ratio of the doubly fed wind turbine generator set is dynamically adjusted by real-time calculation of the SOC adjustment coefficient.

2. The method for dynamic load shedding and frequency regulation coordinated control of a grid-connected wind-storage system based on state of charge drive according to claim 1 is characterized in that: Step 2 is as follows: The rotor-side converter adopts VSG control. Based on the virtual phase angle and voltage amplitude generated by VSG control, the rotor voltage is generated by voltage and current dual closed-loop control, and the active power and reactive power on the stator side are decoupled. Maximum power tracking uses wind speed, output active power of the doubly-fed wind turbine and rotor speed as input parameters, calculates the active power reference value in real time, and uses the active power reference value as the input power command of the VSG to adjust the output power of the doubly-fed wind turbine; The capacitor energy storage system adopts virtual droop control to dynamically adjust the active power reference values ​​of the wind turbine and energy storage so that their output power changes in coordination.

3. The method for dynamic load shedding and frequency regulation coordinated control of a grid-connected wind-storage system based on state of charge drive according to claim 2 is characterized in that: Step 3 includes the following steps: Step 31: Detect the grid frequency deviation and change rate in real time, and calculate the total power change required to be provided by the doubly-fed wind turbine generator set; Step 32: When the wind turbine is in a load-reduced overspeed operation state, the doubly-fed wind turbine generator system reduces the wind energy utilization coefficient by increasing the tip speed ratio, outputs suboptimal power, and reserves frequency regulation standby capacity; Step 33: Based on the current rotor speed and load reduction level, the reserved frequency regulation capacity is calculated as the limit frequency regulation power. The actual frequency regulation power is controlled to be less than or equal to the limit frequency regulation power to ensure that the rotor speed does not fall below the optimal speed. Step 34: Adjust the output electromagnetic power of the doubly-fed wind turbine generator set according to the total power variation. When the frequency drops, the power is increased from the suboptimal power to release the rotor kinetic energy. When the frequency rises again, the power is reduced to absorb energy and restore the rotor speed. Step 35: After the grid frequency stabilizes, the power reference value returns to the initial load reduction power, restoring the initial frequency regulation reserve capacity to ensure subsequent frequency regulation capabilities.

4. The method for dynamic load shedding and frequency regulation coordinated control of a grid-connected wind-storage system based on state of charge drive according to claim 3 is characterized in that: The total power change calculation formula in step 31 is: in, , indicating that the active power reference value controlled by VSG is determined by the wind turbine MPPT output power and FM output power composition; Indicates the primary frequency modulation coefficient; Indicates the grid angular frequency deviation, Indicates the rate of change of grid angular frequency deviation; represents the damping coefficient; represents the moment of inertia; Indicates the total power change; In step 32, the wind turbine reduces the wind energy utilization coefficient by increasing the tip speed ratio, and the output suboptimal power calculation formula is: in, Indicates load shedding The suboptimal power obtained by the wind turbine is Indicates the initial load shedding level; represents the wind energy utilization coefficient in the load-reduced state, and , represents the optimal wind energy utilization coefficient; Indicates the air density; represents the fan swept area; Indicates the fan rotor speed; Indicates the fan blade radius; Indicates the tip speed ratio in the unloaded state; represents the suboptimal power proportionality factor; The calculation formula for the limit frequency modulation power in step 33 is: in, Indicates the fan's maximum frequency modulation power; represents the maximum power tracking coefficient; represents the optimal tip speed ratio.

5. The method for coordinated control of dynamic load shedding and frequency regulation of a grid-connected wind-storage system based on state of charge drive according to claim 4 is characterized in that: The formula for calculating the active power reduction ratio of suboptimal power to maximum power during load reduction is: in, Indicates the active power load reduction ratio of suboptimal power relative to maximum power; represents suboptimal power; Indicates maximum power; The SOC adjustment coefficient is introduced to establish the SOC dynamic adjustment mechanism. The calculation formula is: in, Indicates the power after dynamic adjustment; Indicates the SOC adjustment coefficient.

6. The method for coordinated control of dynamic load shedding and frequency regulation of a grid-connected wind-storage system based on state of charge drive according to claim 5 is characterized in that: The SOC adjustment coefficient uses a piecewise logistic function according to the range of the energy storage SOC. The calculation formula is: in, Indicates the curve change rate factor; Indicates the initial power of energy storage; Indicates the maximum output power of energy storage; Represent the minimum and maximum values ​​of SOC respectively; is an intermediate parameter, whose value is .

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