Self-adaptive cooperative primary frequency modulation control method and device for energy storage battery based on SOC and frequency difference partition

Abstract

The invention relates to an energy storage battery self-adaptive cooperative primary frequency modulation control method based on SOC and frequency difference partition, and the method comprises the steps: obtaining a frequency deviation value, and calculating a frequency deviation change rate; comparing the frequency deviation value with the frequency modulation dead zone; judging and selecting virtual inertia control or negative virtual inertia control, and calculating output of a primary frequency modulation response stage; calculating droop control output in a primary frequency modulation response stage; and calculating the total output of the energy storage battery. According to the method, rapid response is performed aiming at the initial rate of frequency change, and rapid fluctuation of the frequency is effectively inhibited; the stability of the frequency recovery process is remarkably improved, smooth and continuous adjustment can be carried out according to the real-time system frequency requirement and the energy storage SOC level, the energy storage output process is more stable and more friendly, the frequency modulation power requirement is preferentially guaranteed under the frequency emergency condition, the frequency modulation capacity of energy storage can be fully exerted in the SOC normal interval, and the energy storage efficiency is improved. And the battery safety is guaranteed preferentially.

Description

Technical Field

[0001] This invention relates to the field of primary frequency regulation technology for power grids, and in particular to an adaptive and coordinated primary frequency regulation control method and device for energy storage batteries based on SOC and frequency difference partitioning. Background Technology

[0002] With the large-scale grid connection of clean energy power generation, such as wind power and photovoltaic power, the equivalent inertia of the power system has been significantly reduced. When active power disturbances occur, the frequency fluctuation amplitude of the power grid increases and the frequency change rate accelerates. Wind power and photovoltaic power generation are affected by the environment and geographical location, thus exhibiting volatility and randomness. Their large-scale grid connection has seriously affected the safe and stable operation of the power system.

[0003] Traditional thermal power plants have slow frequency regulation response speeds, with delays of several to tens of seconds in their primary frequency regulation response, resulting in insufficient regulation precision and making it difficult to meet the primary frequency regulation requirements of modern power grids. Meanwhile, the rapid development of energy storage technology has made energy storage batteries a new method to assist in primary frequency regulation of the power grid. Energy storage battery systems can respond at millisecond speeds, offer high regulation precision, and possess bidirectional regulation capabilities. Furthermore, they are not limited by geography or fuel, making energy storage batteries a key technology for participating in primary frequency regulation of the power grid. When used in conjunction with traditional generator sets, they can effectively improve the primary frequency regulation capability of the power grid. Therefore, the control methods and strategies for energy storage batteries to participate in primary frequency regulation of the power grid have become a key area of ​​current research.

[0004] In existing technologies for energy storage batteries participating in primary grid frequency regulation, the main architectures employed are virtual droop control and virtual inertial control. However, when combining these two control methods, secondary disturbances can easily occur during frequency recovery, affecting frequency stability. Furthermore, regarding battery output, traditional fixed droop control coefficient methods use a fixed unit adjustment power, which may lead to overcharging and over-discharging of the State of Charge (SOC) during emergency frequency regulation, and insufficient output during normal frequency regulation. While some variable droop coefficient methods consider SOC protection, they do not deeply integrate with frequency deviation zoning, and the coefficient curves are often stepped, easily causing sudden changes in energy storage output. This results in a contradiction: easy overcharging and over-discharging of the SOC during priority frequency regulation, and insufficient frequency regulation during priority SOC protection. Summary of the Invention

[0005] To address the issues of secondary frequency drops and short battery life in existing technologies where energy storage participates in primary frequency regulation of the power grid based on a combination of virtual inertial control and virtual droop control, the primary objective of this invention is to provide an adaptive and cooperative primary frequency regulation control method for energy storage batteries based on SOC and frequency difference partitioning. This method can effectively suppress sharp frequency fluctuations, making the energy storage output process smoother and more user-friendly.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an adaptive cooperative primary frequency regulation control method for energy storage batteries based on SOC and frequency difference partitioning, the method comprising the following sequential steps:

[0007] (1) Obtain the frequency deviation value Calculate the rate of change of frequency deviation ;

[0008] (2) The frequency deviation value Compared with the frequency regulation dead zone, if the energy storage stops charging and discharging within the frequency regulation dead zone, the frequency regulation is not started; if it is not within the frequency regulation dead zone, the energy storage is started to participate in the primary frequency regulation and proceeds to step (3).

[0009] (3) Based on the frequency deviation value and frequency deviation change rate The product of these factors determines whether to select virtual inertial control or negative virtual inertial control, and the output of virtual inertial control during the primary frequency modulation response stage is calculated. ;

[0010] (4) Obtain the state of charge of the energy storage battery, divide the frequency and SOC into zones, and calculate the virtual control droop coefficient of the energy storage battery when virtual control droop is used based on the frequency zone and SOC zone. Calculate the droop control output during the first frequency modulation response stage. ;

[0011] (5) Calculate the total output of the energy storage battery Based on the total output of the energy storage battery Control the charging and discharging of the energy storage battery;

[0012] (6) Allow the energy storage battery to participate in the primary frequency regulation control under adaptive control. After the primary frequency regulation is performed, the frequency deviation value is judged again. If the frequency is within the dead zone, the frequency modulation ends; otherwise, repeat steps (1) to (5).

[0013] In step (1), the frequency deviation The formula is:

[0014] ;

[0015] In the formula, The rated frequency of the power grid. = 50Hz; This is the actual frequency of the power grid.

[0016] In step (2), the frequency modulation dead zone range is -0.033Hz to +0.033Hz.

[0017] Step (3) specifically refers to:

[0018] when At that time, virtual inertial control is used, and calculations are performed. ;

[0019] when At that time, negative virtual inertial control is used, and calculations are performed. ;

[0020] In the formula, This is the virtual inertial control coefficient for energy storage.

[0021] In step (4), the frequency partitioning specifically refers to: according to Based on the absolute value, divide the system into three adjustment intervals:

[0022] Dead zone: This interval The downward output force is not calculated;

[0023] Normal adjustment range: 0.033Hz < | For values ​​≤ 0.2Hz, the SOC range and charge / discharge state need to be considered, and the SOC sine function needs to be used for calculation. ;

[0024] Emergency Adjustment Zone: | |> 0.2Hz, prioritizing FM performance, take , This is the maximum adjustable power per unit.

[0025] In step (4), the partitioning of SOC specifically refers to dividing the real-time SOC value into three intervals:

[0026] Danger Zone: ≤ or ≥ Prioritize protecting SOC and reduce ;

[0027] Transition zone: < ≤ or ≤ < Smooth transition ;

[0028] Normal area: < < Priority should be given to frequency modulation. Take the maximum value;

[0029] In the formula, State of charge, which is the percentage of the current remaining charge of the energy storage battery relative to its rated capacity; This refers to the minimum allowable capacity threshold for energy storage batteries. This refers to the maximum allowable capacity threshold for energy storage batteries. This represents the lower capacity threshold of the energy storage battery. This represents the higher capacity threshold of the energy storage battery.

[0030] In step (4), the Adaptive computation:

[0031] In discharge state The value can be: ;

[0032] In charging state The value can be:

[0033] ;

[0034] In the formula, State of charge, which is the percentage of the current remaining charge of the energy storage battery relative to its rated capacity; This refers to the minimum allowable capacity threshold for energy storage batteries. This refers to the maximum allowable capacity threshold for energy storage batteries. This represents the lower capacity threshold of the energy storage battery. This represents the higher capacity threshold of energy storage batteries;

[0035] Calculate the droop control output during the first frequency modulation response stage :

[0036] ;

[0037] The negative sign ensures that energy storage discharges when the frequency decreases and charges when the frequency increases.

[0038] In step (5), the total output of the energy storage battery for:

[0039] .

[0040] Another object of the present invention is to provide an electronic device comprising:

[0041] Processor; and

[0042] The memory stores computer program instructions that, when executed by the processor, cause the processor to perform the adaptive cooperative primary frequency regulation control method for energy storage batteries based on SOC and frequency difference partitioning as described above.

[0043] The present invention also provides a computer-readable storage medium having stored thereon computer program instructions, which, when executed by a processor, cause the processor to perform the adaptive cooperative primary frequency regulation control method for energy storage batteries based on SOC and frequency difference partitioning as described above.

[0044] As can be seen from the above technical solution, the beneficial effects of the present invention are as follows: First, by organically combining virtual inertial control and virtual droop control, the strategy effectively covers different stages of frequency disturbance. Virtual inertial control provides a rapid response at the initial moment of frequency change, effectively suppressing sharp frequency fluctuations; while virtual droop control focuses on improving the steady-state frequency deviation of the system. When the system frequency enters the recovery period, the strategy activates corresponding negative virtual inertial control to suppress possible frequency overshoot or oscillation. This mechanism significantly improves the smoothness of the frequency recovery process and avoids the secondary disturbance problem that may be caused by improper adjustment in traditional control. Second, the present invention divides the frequency deviation into zones and SOC intervals. Deep coupling enables the droop coefficient to be smoothly and continuously adjusted according to the real-time system frequency demand and energy storage SOC level, avoiding the power command abrupt changes that may be caused by traditional piecewise linear methods. This makes the energy storage output process more stable and user-friendly. On the one hand, it prioritizes the frequency regulation power demand in frequency emergencies. On the other hand, it allows the strategy to fully utilize the frequency regulation capability of energy storage within the normal SOC range. When the SOC is close to the limit, it can automatically and smoothly reduce the output priority to ensure battery safety and prevent overcharging and over-discharging. Thus, while providing high-quality frequency regulation services, it greatly extends the service life of the energy storage system and improves its long-term economic efficiency and sustainability. Attached Figure Description

[0045] Figure 1 This is a flowchart of the method of the present invention;

[0046] Figure 2 This invention is based on the droop control curve of the SOC sine function;

[0047] Figure 3 This is a schematic diagram of the SOC partitioning of the energy storage battery of the present invention;

[0048] Figure 4 This is the random load disturbance variation curve of the present invention;

[0049] Figure 5 This is a frequency deviation comparison chart of the present invention. Detailed Implementation

[0050] like Figure 1 As shown, an adaptive cooperative primary frequency regulation control method for energy storage batteries based on SOC and frequency difference partitioning is proposed. The method includes the following sequential steps:

[0051] (1) Obtain the frequency deviation value Calculate the rate of change of frequency deviation ;

[0052] (2) The frequency deviation value Compared with the frequency regulation dead zone, if the energy storage stops charging and discharging within the frequency regulation dead zone, the frequency regulation is not started; if it is not within the frequency regulation dead zone, the energy storage is started to participate in the primary frequency regulation and proceeds to step (3).

[0053] (3) Based on the frequency deviation value and frequency deviation change rate The product of these factors determines whether to select virtual inertial control or negative virtual inertial control, and the output of virtual inertial control during the primary frequency modulation response stage is calculated. ;

[0054] (5) Obtain the state of charge of the energy storage battery, divide the frequency and SOC into zones, and calculate the virtual control droop coefficient of the energy storage battery when virtual control droop is used based on the frequency zone and SOC zone. Calculate the droop control output during the first frequency modulation response stage. ;

[0055] (5) Calculate the total output of the energy storage battery Based on the total output of the energy storage battery Control the charging and discharging of the energy storage battery;

[0056] (6) Allow the energy storage battery to participate in the primary frequency regulation control under adaptive control. After the primary frequency regulation is performed, the frequency deviation value is judged again. If the frequency is within the dead zone, the frequency modulation ends; otherwise, repeat steps (1) to (5).

[0057] In step (1), the frequency deviation The formula is:

[0058] ;

[0059] In the formula, The rated frequency of the power grid. = 50Hz; This is the actual frequency of the power grid.

[0060] In step (2), the frequency modulation dead zone range is -0.033Hz to +0.033Hz.

[0061] Step (3) specifically refers to:

[0062] when At that time, virtual inertial control is used, and calculations are performed. ;

[0063] when At that time, negative virtual inertial control is used, and calculations are performed. ;

[0064] In the formula, This is the virtual inertial control coefficient for energy storage.

[0065] In step (4), the frequency partitioning specifically refers to: according to Based on the absolute value, divide the system into three adjustment intervals:

[0066] Dead zone: This interval The downward output force is not calculated;

[0067] Normal adjustment range: 0.033Hz < | For values ​​≤ 0.2Hz, the SOC range and charge / discharge state need to be considered, and the SOC sine function needs to be used for calculation. ;

[0068] Emergency Adjustment Zone: | |> 0.2Hz, prioritizing FM performance, take , This is the maximum adjustable power per unit.

[0069] In step (4), the partitioning of SOC specifically refers to dividing the real-time SOC value into three intervals:

[0070] Danger Zone: ≤ or ≥ Prioritize protecting SOC and reduce ;

[0071] Transition zone: < ≤ or ≤ < Smooth transition ;

[0072] Normal area: < < Priority should be given to frequency modulation. Take the maximum value;

[0073] In the formula, State of charge, which is the percentage of the current remaining charge of the energy storage battery relative to its rated capacity; This refers to the minimum allowable capacity threshold for energy storage batteries. This refers to the maximum allowable capacity threshold for energy storage batteries. This represents the lower capacity threshold of the energy storage battery. This represents the higher capacity threshold of the energy storage battery.

[0074] In step (4), the Adaptive computation:

[0075] In discharge state The value can be: ;

[0076] In charging state The value can be:

[0077] ;

[0078] In the formula, State of charge, which is the percentage of the current remaining charge of the energy storage battery relative to its rated capacity; This refers to the minimum allowable capacity threshold for energy storage batteries. This refers to the maximum allowable capacity threshold for energy storage batteries. This represents the lower capacity threshold of the energy storage battery. This represents the higher capacity threshold of energy storage batteries;

[0079] Calculate the droop control output during the first frequency modulation response stage :

[0080] ;

[0081] The negative sign ensures that energy storage discharges when the frequency decreases and charges when the frequency increases.

[0082] In step (5), the total output of the energy storage battery for:

[0083] .

[0084] like Figure 2 As shown, Figure 2 This diagram displays a smooth curve showing the droop coefficient of an energy storage battery as a function of its state of charge (SOC) under charging and discharging conditions. The long dashed line represents the discharge coefficient, the short dashed line represents the charging coefficient, and the vertical axis represents the magnitude of the droop coefficient (maximum value is...). The horizontal axis represents the SOC value (covering...). to (Interval). The curve adopts a sine function model to achieve a continuous and smooth transition of coefficients in the SOC transition region, avoiding the sudden output problem of traditional piecewise linear methods. It not only ensures the full frequency regulation capability in the normal SOC range, but also gradually reduces the output when the SOC approaches the dangerous threshold, effectively preventing battery overcharging and over-discharging, and achieving synergy between frequency regulation performance and battery safety.

[0085] like Figure 3 As shown, Figure 3 The five operating ranges of the energy storage battery's State of Charge (SOC) and their corresponding thresholds are clearly defined. =0.9 and =0.1 represents the boundary of the danger zone. =0.55 and =0.45 is the dividing point between the transition zone and the normal zone. The area where the SOC exceeds 0.9 or falls below 0.1 is considered a danger zone, and battery safety should be prioritized; 0.1 0.45 is the charging priority zone, 0.55 0.9 is the discharge priority zone (both are transition zones), achieving a smooth power output transition; 0.45 0.55 represents the normal charging and discharging range, prioritizing the fulfillment of power grid frequency regulation requirements.

[0086] like Figure 4 As shown, Figure 4 The waveform used in the simulation verification is a continuous random load disturbance. The horizontal axis represents time, and the vertical axis represents the load disturbance amplitude (unit: pu). The disturbance duration is 25 seconds, and the amplitude is within -0.05. The disturbance curve, fluctuating randomly within 0.05 pu, simulates active power disturbances caused by fluctuations in renewable energy output and load changes in actual power grid operation. This disturbance curve is used to examine the adaptability of different frequency regulation strategies to dynamic and random disturbances, providing a unified input condition for comparing the frequency control effects of various methods.

[0087] like Figure 5 As shown, Figure 5 The dynamic response of grid frequency deviation under four control strategies was compared. The horizontal axis represents time (in seconds), and the vertical axis represents the frequency deviation value (in Hz). The curves show that under continuous load disturbances, the frequency fluctuation amplitude of primary frequency regulation with energy storage participation is significantly reduced compared to the case without energy storage. Simulation comparisons of the three strategies involving energy storage show that the traditional constant droop coefficient method and the variable droop coefficient method have better primary frequency regulation effects than the case without energy storage, limiting frequency deviation fluctuations to a smaller range. However, they cannot fully utilize the primary frequency regulation capability of energy storage and cannot effectively meet frequency adjustment needs. The method presented in this paper, i.e., the present invention, has the best frequency regulation effect. The designed adaptive energy storage primary frequency regulation integrated strategy allows the energy storage unit to fully utilize its primary frequency regulation capability. The virtual inertial control element reduces the frequency deviation change rate and has the best effect in suppressing sharp frequency fluctuations and improving recovery stability.

[0088] In summary, this invention, through the organic combination of virtual inertial control and virtual droop control, effectively covers different stages of frequency disturbance. Virtual inertial control provides a rapid response at the initial moment of frequency change, effectively suppressing sharp frequency fluctuations; while virtual droop control focuses on improving the steady-state frequency deviation of the system. When the system frequency enters the recovery period, the strategy activates corresponding negative virtual inertial control to suppress possible frequency overshoot or oscillations. This mechanism significantly improves the smoothness of the frequency recovery process and avoids secondary disturbance problems that may be caused by improper adjustment in traditional control. This invention deeply couples the frequency deviation partition with the SOC interval, enabling the following... The vertical coefficient can be smoothly and continuously adjusted according to the real-time system frequency demand and energy storage SOC level, avoiding the sudden power command changes that may be caused by traditional piecewise linear methods. This makes the energy storage output process more stable and user-friendly. On the one hand, it prioritizes the frequency regulation power demand in frequency emergencies. On the other hand, it allows the strategy to fully utilize the frequency regulation capability of energy storage within the normal SOC range. When the SOC is close to the limit, it can automatically and smoothly reduce the output priority to ensure battery safety and prevent overcharging and over-discharging. Thus, while providing high-quality frequency regulation services, it greatly extends the service life of the energy storage system and improves its long-term economic efficiency and sustainability.

[0089] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A SOC and frequency difference partition-based adaptive cooperative primary frequency modulation control method for energy storage batteries, characterized in that: The method comprises the following steps in sequence: (1) Obtain a frequency deviation value , calculate a frequency deviation change rate ; (2) the frequency deviation value In comparison with the frequency modulation dead zone, if the energy storage stops charging and discharging in the frequency modulation dead zone range, the frequency modulation is not started; if it is not in the frequency modulation dead zone range, the energy storage participates in the frequency modulation once, and enters step (3); (3) Based on the frequency deviation value and frequency deviation change rate The product of these factors determines whether to select virtual inertial control or negative virtual inertial control, and the output of virtual inertial control during the primary frequency modulation response stage is calculated. ; (4) Obtain the state of charge of the energy storage battery, partition the frequency and SOC, and calculate the virtual control droop coefficient of the energy storage battery under virtual control droop according to the frequency partition and SOC partition , and calculate the droop control output in the primary frequency regulation response stage ; (5) calculating total output of the energy storage battery controlling the energy storage battery to charge and discharge according to the total output of the energy storage battery controlling the energy storage battery to charge and discharge according to the total output of the energy storage battery (6) Let the energy storage battery participate in the control of primary frequency modulation under adaptive control, and judge the frequency deviation value again after primary frequency modulation whether it is in the frequency modulation dead zone range. If the judgment result is yes, the primary frequency modulation ends, otherwise, the steps (1) to (5) are repeated.

2. The SOC and frequency difference partition-based adaptive coordinated primary frequency control method for energy storage batteries according to claim 1, characterized in that: In step (1), the frequency deviation The formula is: ； wherein is the grid nominal frequency, = 50 Hz; is the grid actual frequency.

3. The SOC and frequency difference partition-based adaptive coordinated primary frequency control method for energy storage batteries according to claim 1, characterized in that: In step (2), the frequency modulation dead zone range is -0.033 Hz to +0.033 Hz.

4. The SOC and frequency difference partition-based adaptive coordinated primary frequency control method for energy storage batteries according to claim 1, characterized in that: Step (3) specifically refers to: When a virtual inertia control is used and a virtual inertia control output is calculated ; When a negative virtual inertia control is used and a virtual inertia control output is calculated ; In the formula, is the virtual inertia control coefficient for energy storage.

5. The SOC and frequency difference partition-based adaptive coordinated primary frequency control method for energy storage batteries according to claim 1, characterized in that: In step (4), the frequency partitioning specifically refers to: according to Based on the absolute value, divide the system into three adjustment intervals: Dead band: This interval , the droop output is not calculated; Normal regulation region: 0.033Hz < |f| < 0.2Hz 0.2Hz, combined with SOC region and charge-discharge state, calculated by SOC sine function ; Emergency adjustment area: ∣ ∣> 0.2Hz, priority protection frequency modulation effect, take , The maximum unit adjustment power.

6. The SOC and frequency difference partition-based adaptive coordinated primary frequency control method for energy storage batteries according to claim 1, characterized in that: In step (4), the SOC partitioning specifically refers to: according to the real-time SOC value, three intervals are divided: Danger zone: ≤ or ≥ , preferentially protect the SOC, reduce ; Transition zone: or , smooth transition ;​​​​ Normal zone: Priority protection of frequency modulation, Take the maximum value;​​ wherein, SoC is the state of charge, i.e. the percentage of the rated capacity of the energy storage battery that is currently remaining; SoCmin is the minimum charge threshold allowed for the energy storage battery; SoCmax is the maximum charge threshold allowed for the energy storage battery; SoCmin is the lower charge threshold for the energy storage battery; SoCmax is the higher charge threshold for the energy storage battery.

7. The SOC and frequency difference partition-based adaptive coordinated primary frequency control method for energy storage batteries according to claim 1, characterized in that: In step (4), the Adaptive computation: In the discharged state The value of the parameter ; in a charged state the value of the parameter ； wherein, SoC is the state of charge, i.e. the percentage of the rated capacity of the energy storage battery that is currently remaining; SoCmin is the minimum charge threshold allowed for the energy storage battery; SoCmax is the maximum charge threshold allowed for the energy storage battery; SoCmin is the lower charge threshold for the energy storage battery; SoCmax is the higher charge threshold for the energy storage battery; Computing a droop control output for a primary frequency response phase : ； Wherein, the negative sign ensures that the energy storage is discharged when the frequency decreases and charged when the frequency increases.

8. The SOC and frequency difference partition-based adaptive coordinated primary frequency control method for energy storage batteries according to claim 1, characterized in that: In step (5), the total output power of the energy storage battery is P = P1+ P2+ P3+ P4+ P5 。 9. An electronic device comprising: a processor; and a memory having computer program instructions stored therein, the computer program instructions, when executed by the processor, causing the processor to perform the SOC and frequency difference partition-based adaptive cooperative primary frequency modulation control method of the energy storage battery according to any one of claims 1-8.

10. A computer-readable storage medium having computer program instructions stored thereon, the computer program instructions, when executed by a processor, causing the processor to perform the SOC and frequency difference partition-based adaptive cooperative primary frequency modulation control method of the energy storage battery according to any one of claims 1-8.

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