Energy storage type SVG primary frequency modulation control method and system based on dynamic droop coefficient

Abstract

The invention belongs to the technical field of power system adjustment, relates to an energy storage type SVG primary frequency modulation control method based on a dynamic droop coefficient, and aims to improve the flexibility and response speed of energy storage type SVG frequency adjustment. According to the method, a Logistic function is adopted to dynamically adjust a droop coefficient, so that the droop coefficient is non-linearly adjusted according to the magnitude of frequency deviation and the change rate; when the frequency deviation is small, the energy storage type SVG adopts a small droop coefficient, and the stability of frequency modulation is kept; when the frequency deviation is relatively large, the droop coefficient is gradually increased through a Logistic function, so that the energy storage type SVG can quickly respond under the condition of large deviation; the dynamic droop coefficient adjusting strategy has the advantages of being high in response speed, high in adjusting precision, high in frequency stability and the like. In addition, the invention further designs an energy storage type SVG primary frequency modulation control system, and flexible adjustment of the frequency of the power grid side is further achieved.

Description

Technical Field

[0001] The invention belongs to the field of power system frequency regulation, and relates to an energy storage type SVG primary frequency regulation control method and system based on a dynamic droop coefficient. Background Art

[0002] As the penetration rate of renewable energy generation continues to increase, the frequency regulation capability of traditional synchronous generators in power systems has gradually decreased, resulting in a significant increase in grid frequency volatility. Due to the volatility and uncertainty of the output of renewable energy generation (such as wind power and photovoltaics), it is impossible to stably provide inertia and frequency regulation capabilities through traditional synchronous generators. Faced with this change, the frequency regulation means of traditional power systems have been unable to cope with the increasingly complex frequency regulation needs. In this context, energy storage static VAR generators (energy storage SVGs) have become an important frequency regulation means due to their fast response speed and high regulation accuracy. Energy storage SVGs can quickly respond to frequency deviations and provide effective support for modern power systems.

[0003] However, the existing frequency modulation strategy of energy storage SVG is usually based on a fixed droop coefficient. This fixed droop coefficient control strategy has the technical defect of being unable to adapt to the dynamic changes of grid frequency fluctuations. When the frequency fluctuation is large, the fixed droop coefficient may lead to insufficient frequency modulation response and fail to effectively suppress frequency deviation; when the frequency fluctuation is small, the fixed droop coefficient may cause the energy storage device to over-respond to small frequency fluctuations, resulting in frequent charging and discharging, and increasing the loss and wear of the energy storage system. Therefore, the frequency modulation strategy based on the fixed droop coefficient has the problem of poor frequency modulation effect in actual application, and cannot give full play to the role of energy storage SVG in frequency stability.

[0004] Based on this, it is urgent to adjust the existing energy storage type SVG frequency modulation strategy to solve the technical defects of the above-mentioned existing technology. Summary of the invention

[0005] One of the purposes of the present invention is to provide a dynamic droop coefficient adjustment strategy based on the Logistic function to address the deficiencies of the prior art, and to apply it to the primary frequency regulation control of energy storage type SVG, so as to achieve more flexible and efficient frequency regulation and ensure the stability of the grid side frequency.

[0006] In order to achieve the above-mentioned invention object, the present invention implements the following technical solutions: The energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient includes the following steps: S101, constructing a primary frequency modulation control equation for an energy storage type SVG, where the primary frequency modulation control equation for the energy storage type SVG is used to control the output power of the energy storage type SVG; S201. According to the droop external characteristics of the energy storage type SVG, a dynamic droop coefficient equation is constructed through a Logistic function. The dynamic droop coefficient equation dynamically adjusts the droop coefficient in the primary frequency modulation control equation of the energy storage type SVG according to the frequency deviation fluctuation in the power grid; S301. Input the frequency deviation of the power grid into a dynamic droop coefficient equation to obtain a real-time droop coefficient and a primary frequency modulation output power of the energy storage type SVG. The energy storage type SVG performs primary frequency modulation on the power grid according to the primary frequency modulation output power.

[0007] The above technical solution produces the following technical effects: In view of the technical defects of the existing energy storage type SVG primary frequency modulation control strategy, the present invention proposes a dynamic droop coefficient adjustment method implemented by a Logistic function to solve the defects of a fixed droop coefficient. This method enables the droop coefficient to be dynamically adjusted with the real-time frequency deviation by introducing the Logistic function. Specifically, the Logistic function provides a nonlinear adjustment mechanism, so that when the frequency deviation is small, the frequency modulation response intensity is relatively weak, thereby avoiding the energy storage system from over-responding to small frequency fluctuations; when the frequency deviation is large, the droop coefficient increases accordingly, ensuring that the system can quickly provide sufficient regulation power to stabilize the frequency. This dynamic adjustment strategy can significantly improve the frequency modulation effect and reduce frequency fluctuations.

[0008] As a further improvement to the energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient of the present invention, the dynamic droop coefficient equation in step S201 is:

[0009] in, is the frequency deviation; is the droop coefficient, which changes with the frequency deviation; is the maximum value of the sag coefficient; is the minimum value of the droop coefficient; It is the curve slope adjustment factor in the dynamic droop coefficient equation, which controls the sensitivity of the response; It is the center point of the droop system adjustment, corresponding to a specific frequency deviation.

[0010] As a further improvement to the energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient of the present invention, The value range is: 5-15; The value range is: 0-1.

[0011] As a further improvement to the energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient of the present invention, The value range is: 5-20.

[0012] As a further improvement to the energy storage type SVG primary frequency modulation control method based on the dynamic droop coefficient of the present invention, the process of the primary frequency modulation of the power grid in step S301 is based on the frequency change amount and frequency change rate The two indicators divide the process of energy storage SVG participating in primary frequency modulation into three stages: The first stage is to meet and , at this time, the frequency deviation does not exceed the dead zone threshold, and only a slight correction of the frequency deviation is required through the energy storage SVG; The second stage is to meet and At this time, the frequency deviation is large and deteriorates seriously, and the energy storage SVG begins to intervene on a large scale to adjust the frequency deviation; The third stage is to satisfy At this time, the frequency deviation gradually decreases, and the energy storage SVG begins to gradually reduce the adjustment of the frequency deviation; in, is the dead zone threshold.

[0013] As a further improvement to the energy storage type SVG primary frequency modulation control method based on the dynamic droop coefficient of the present invention, the energy storage type SVG primary frequency modulation control equation is:

[0014] in, is the output power of the energy storage SVG; is the initial output power of the energy storage SVG; is the droop coefficient, which changes with the frequency deviation; is the frequency deviation.

[0015] As a further improvement to the energy storage type SVG primary frequency modulation control method based on the dynamic droop coefficient of the present invention, the energy storage type SVG primary frequency modulation control equation is 0.

[0016] The second object of the present invention is to address the deficiencies of the prior art and to provide an energy storage type SVG primary frequency modulation control system comprising any of the above-mentioned energy storage type SVG primary frequency modulation control methods based on a dynamic droop coefficient, so as to achieve flexible adjustment of the grid side frequency.

[0017] In order to achieve the above technical objectives, the present invention implements the following technical solutions: A primary frequency modulation control system for an energy storage type SVG comprises an energy storage type SVG and a control module electrically connected to the energy storage type SVG, wherein the control module obtains a real-time frequency deviation through real-time frequency calculation on a power grid side, and obtains a real-time droop coefficient and a primary frequency modulation output power of the energy storage type SVG through calculation of the real-time frequency deviation according to a primary frequency modulation control method for an energy storage type SVG based on a dynamic droop coefficient as claimed in any one of claims 1 to 7; the control module outputs the primary frequency modulation output frequency to the energy storage type SVG, and drives the energy storage type SVG to adjust the frequency deviation on the power grid side; and a frequency detection module is electrically connected to the control module, and is used to detect the real-time frequency on the power grid side and transmit the real-time frequency to the control module.

[0018] The above technical solution produces the following technical effects: The control module of the present invention significantly improves the response speed of the energy storage type SVG frequency modulation by calculating the frequency deviation in real time and dynamically adjusting the droop coefficient. In the case of a large frequency deviation, the energy storage type SVG primary frequency modulation control system of the present invention can quickly adjust the output power of the energy storage type SVG, thereby effectively restoring the frequency to a normal range. Compared with the frequency modulation method with a fixed droop coefficient, the dynamic control system has more advantages in frequency recovery time, can effectively suppress frequency fluctuations, and ensure the stable operation of the power grid.

[0019] As a further improvement to an energy storage type SVG primary frequency modulation control system of the present invention, the energy storage type SVG includes an active power compensation module and a reactive power compensation module, and the active power compensation module and the reactive power compensation module can realize the power four-quadrant operation of the energy storage type SVG through decoupling control.

[0020] As a further improvement of an energy storage type SVG primary frequency modulation control system of the present invention, the active power compensation module is a super capacitor module, which is used to provide primary frequency modulation output power to the grid side; The reactive power compensation power module is at least two full-bridge modular multilevel converters; each full-bridge modular multilevel converter can independently perform voltage control and reactive power regulation on the grid side. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 It is a flow chart of the primary frequency modulation control method of energy storage type SVG based on dynamic droop coefficient in Example 1 of the present invention; Figure 2 This is a frequency adjustment stage division diagram in Embodiment 2 of the present invention; Figure 3 is a curve of the droop coefficient with respect to the frequency deviation in Example 3 of the present invention; Figure 4 It is a structural schematic diagram of the energy storage type SVG primary frequency modulation control system in Example 4 of the present invention; Figure 5 Schematic diagram of the structure of the energy storage type SVG in Example 4 of the present invention; in: 11- Active power compensation module; 12- Reactive power compensation module; DETAILED DESCRIPTION The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0022] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0023] To facilitate understanding of the solutions provided by the following embodiments of the present invention, before describing the technical solutions provided by the present invention, the terms involved in the present invention are explained as follows: Energy storage SVG, also known as energy storage static var generator (Static Var Generator), is a device that can provide reactive power compensation and active power regulation. Combined with energy storage system, it can realize dual control of frequency and voltage of power grid. Its rapid response capability makes it an important auxiliary frequency regulation means, especially in power systems with a high proportion of new energy.

[0024] Primary frequency regulation is the regulation phase in the power grid that responds to frequency deviations by quickly adjusting output power. Primary frequency regulation is the automatic response of power generation equipment or energy storage equipment in a short period of time when the power grid frequency deviates. It is usually completed within a few seconds and is the first line of defense for power grid frequency control, used to quickly mitigate frequency deviations and prevent further deterioration of the frequency.

[0025] Frequency deviation is the difference between the actual grid frequency and the rated frequency, where the rated frequency (such as 50Hz or 60Hz) is the target frequency when the grid is operating normally. Frequency deviation indicates the degree of deviation between the current grid operating frequency and the target frequency. Frequency deviation is an important indicator for measuring grid frequency stability. Excessive deviation may affect the safe operation of system equipment.

[0026] Real-time frequency is the actual operating frequency of the power grid at a certain moment. It is the frequency value obtained by the frequency measuring device at the current moment. The measurement of real-time frequency is very important for judging whether the power grid is stable and whether frequency regulation is required. Energy storage SVG uses real-time frequency to judge whether frequency regulation is required.

[0027] The Logistic function is an S-curve function used for control, which is scaled and offset adjusted to adapt to specific applications. The Logistic function is a nonlinear function, and its output presents a smooth S-curve. By adjusting the scaling and offset of the function, it can be adapted to specific control requirements. In the present invention, the Logistic function is used to dynamically adjust the droop coefficient so that it changes flexibly with the change of frequency deviation, thereby achieving the adaptability of the frequency modulation response.

[0028] The dead zone threshold refers to an input range set in the control system to avoid meaningless or overly sensitive responses to small input signals (such as frequency change, frequency change rate). Within this range, the control system will not react to reduce the response to meaningless fluctuations. In the frequency regulation of the power system, the dead zone threshold is used to define the frequency change amplitude or rate that requires frequency regulation measures. When the frequency change or change rate is lower than the dead zone threshold, the system believes that the frequency deviation is not enough to threaten the stability of the system, so the frequency regulation action will not be triggered.

[0029] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

[0030] Example 1 like Figure 1 As can be seen from the flowchart shown, in order to solve the significant defects of the prior art energy storage type SVG using a fixed droop coefficient method for primary frequency modulation when facing grid frequency fluctuations, the present invention proposes a dynamic droop coefficient adjustment strategy based on the Logistic function and applies it to the primary frequency modulation control of energy storage type SVG. Specifically, the present invention's primary frequency modulation control method of energy storage type SVG based on dynamic droop coefficient includes the following steps: S101, constructing a primary frequency modulation control equation for an energy storage type SVG, where the primary frequency modulation control equation for the energy storage type SVG is used to control the output power of the energy storage type SVG; S201. According to the droop external characteristics of the energy storage type SVG, a dynamic droop coefficient equation is constructed through a Logistic function. The dynamic droop coefficient equation dynamically adjusts the droop coefficient in the primary frequency modulation control equation of the energy storage type SVG according to the frequency deviation fluctuation in the power grid; S301. Input the frequency deviation of the power grid into a dynamic droop coefficient equation to obtain a real-time droop coefficient and a primary frequency modulation output power of the energy storage type SVG. The energy storage type SVG performs primary frequency modulation on the power grid according to the primary frequency modulation output power.

[0031] Among them, the primary frequency modulation control equation of energy storage type SVG in the specific implementation process is:

[0032] in, is the output power of the energy storage SVG; is the initial output power of the energy storage SVG; is the droop coefficient, which changes with the frequency deviation; is the frequency deviation. In the specific implementation process, the energy storage type SVG primary frequency modulation control equation is 0 and can be ignored. Furthermore, it can be seen from the above-mentioned energy storage type SVG primary frequency modulation control equation that the existing technical solution cannot effectively adapt to grid frequency fluctuations due to the solidification of the droop coefficient, thereby affecting the frequency modulation effect. In order to solve this problem, the present invention proposes a dynamic droop coefficient adjustment strategy based on the Logistic function. The Logistic function can dynamically adjust the droop coefficient according to the size of the frequency deviation, so that the energy storage type SVG can more flexibly adjust the output power when the grid frequency fluctuates, thereby improving the effect of primary frequency modulation. Specifically, the basic expression of the Logistic function is:

[0033] in, is the independent variable (can be any real number); e is the base of the natural logarithm, which is approximately 2.718. In the basic expression of the Logistic function above, the function It is always between 0 and 1, and the graph of the Logistic function presents a smooth S-shape with two upper and lower asymptotes (0 and 1). This is consistent with the variation characteristics of the droop coefficient in primary frequency modulation. However, considering that the droop coefficient of the present invention should be combined with the characteristics of the moments when the grid frequency changes slightly and the moments when the changes are drastic, the Logistic function needs to be appropriately adjusted. That is, considering that in the stage when the frequency deterioration is not serious, the energy storage type SVG does not perform significant frequency adjustment, and only needs to make a slight correction to the frequency deviation. Therefore, the present invention scales and offsets the Logistic function to adapt to the characteristics of grid frequency fluctuations. The adjusted Logistic function can be expressed as:

[0034] Where L is the scaling factor, which represents the maximum amplitude of the Logistic curve; is the offset, which is used to change the starting position or the lowest value of the entire function; k is the steepness of the curve; is the center point of the Logistic function curve (determines the symmetry center of the curve); in the above basic expression, the Logistic function The value range of is limited to the interval (0, 1). However, in view of the requirement of the present invention that when the frequency deviation is small, the droop coefficient should be controlled at a lower level (i.e., the lower limit value); and when the frequency deviation is large, the droop coefficient needs to be adjusted to a higher level (i.e., the upper limit value). Therefore, the above-mentioned scaled and offset Logistic function provides a nonlinear adjustment mechanism, so that when the frequency deviation is small, the frequency modulation response intensity is relatively weak, thereby avoiding the excessive response of the energy storage system to small frequency fluctuations; and when the frequency deviation is large, the droop coefficient increases accordingly, ensuring that the system can quickly provide sufficient regulation power to stabilize the frequency. This dynamic adjustment strategy can significantly improve the frequency modulation effect and reduce frequency fluctuations.

[0035] Furthermore, in order to more clearly express the dynamic adjustment of the droop coefficient by the Logistic function in the present invention, the above-mentioned Logistic function after scaling and offset processing can be further expressed as:

[0036] in, is the frequency deviation; is the droop coefficient, which changes with the frequency deviation; is the maximum value of the sag coefficient; is the minimum value of the droop coefficient; is the curve slope adjustment factor in the dynamic droop coefficient equation, controlling the sensitivity of the response; is the center point of the droop system adjustment, corresponding to a specific frequency deviation. Among them, in the above-mentioned scaled and offset Logistic function, L is the upper limit of the function, which determines the range of the curve. In this formula, L is The purpose is to make the range of the Logistic function cover the adjustment range of the droop coefficient. Covering In this way, the output of the Logistic function changes from the minimum value to At the beginning, as the frequency deviation changes, it gradually rises to the maximum value Specifically, when the frequency deviation is small (close to zero or the deviation is small), The value of is close to zero, Approximately ; When the frequency deviation is large (greater than hour), The value of approaches 1. Approximately +( )= . This ensures The output is arrive changes, for The maximum value of .

[0037] In summary, in the Logistic function with scaling and offset, the present invention adjusts the scaling factor L to , plus the offset , so that the output range of the entire function is from arrive This adjustment method ensures that when the frequency deviation is small, the system can respond slightly with a smaller droop coefficient, and when the frequency deviation increases, the system will respond quickly with a higher droop coefficient, achieving flexible regulation of the grid frequency.

[0038] Furthermore, when the frequency deviation is small and the deviation between the real-time frequency of the power grid and the rated frequency has not yet reached a level that requires a significant adjustment, the output of the Logistic function is close to , the droop coefficient is kept at a low level. By adopting a smaller droop coefficient, the system can maintain the smoothness of frequency modulation and avoid over-response to small fluctuations in frequency. At the same time, this approach also helps to reduce the power output of energy storage SVG, extend the service life of the equipment, and avoid frequent charging and discharging operations.

[0039] When the frequency deviation gradually increases and the frequency of the power grid deviates from the rated value to a certain extent, the system needs to take a more active frequency regulation response. At this time, the nonlinear characteristics of the Logistic function make the droop coefficient gradually increase, approaching , so that the energy storage SVG provides a stronger rapid regulation at this stage, which can effectively curb the further expansion of frequency deviation and prevent the negative impact of low or high frequency on the stability of the power grid. That is, when the frequency deviation reaches a large level, the system adjusts the Logistic function to make the droop coefficient close to its maximum value. At this time, the energy storage SVG provides fast and strong active power output under large deviation conditions to ensure that the frequency returns to a safe range as soon as possible. Since the output change rate of the Logistic function is significantly accelerated when the deviation is large, it ensures that severe frequency fluctuations can be dealt with in a timely manner.

[0040] Example 2 like Figure 2 As shown, in order to further improve the present invention to solve the significant defects of the prior art energy storage type SVG using a fixed droop coefficient method to perform a frequency modulation process when facing grid frequency fluctuations. Specifically, in step S301, the grid performs a frequency modulation process based on the frequency change amount. and frequency change rate The two indicators divide the process of energy storage SVG participating in primary frequency modulation into three stages: The first stage is to meet and At this time, the frequency deviation does not exceed the dead zone threshold, and only a slight correction of the frequency deviation is required through the energy storage SVG; is the dead zone threshold. Since the frequency deviation is small at this time and does not exceed the adjustment threshold range, the energy storage SVG does not perform significant frequency adjustment, and only needs to make a slight correction to the frequency deviation to avoid the energy storage SVG from over-responding to small frequency fluctuations.

[0041] The second stage is the stage of severe frequency deterioration, meeting and At this time, the frequency deviation is large and deteriorates seriously, and the energy storage SVG needs to respond quickly to provide active power support and increase the frequency regulation of the power grid to prevent the frequency from further declining. The energy storage SVG will begin to intervene on a large scale to adjust the frequency.

[0042] The third stage is to satisfy At this time, the frequency deviation gradually decreases, and the energy storage SVG begins to gradually reduce the adjustment of the frequency deviation.

[0043] It can be seen that in the present invention, during the process of reducing the frequency deviation, the output value of the Logistic function will gradually decrease, thereby gradually reducing the droop coefficient. This means that the frequency modulation response intensity of the energy storage SVG will weaken as the frequency deviation decreases, until the frequency deviation returns to the normal range, and the system will no longer perform significant frequency regulation. This phased frequency modulation strategy can not only effectively cope with fluctuations in grid frequency, but also ensure the stable operation of the energy storage SVG and extend its service life. Through this method of dynamically adjusting the droop coefficient, the energy storage SVG can respond to changes in grid frequency more intelligently and achieve more accurate and efficient frequency control.

[0044] The other details that are the same as those in Example 1 are not described in detail in this example.

[0045] Example 3 like Figure 3 As shown, the difference from Example 1 is that the dynamic droop coefficient equation in step S201 of the present invention is middle, The value range is: 5-15; The value range is: 0-1; and The value range setting can flexibly adjust the response of the energy storage SVG to the grid frequency change. In practical applications, the appropriate parameter value can be selected according to the specific situation and needs of the grid to achieve the best frequency regulation effect. For example, when the grid has a high requirement for frequency stability, the value of The value of can make the energy storage SVG provide stronger regulation ability when the frequency deviation is large; on the contrary, if the power grid can tolerate a certain degree of frequency fluctuation, or in order to protect the energy storage SVG, it can be appropriately reduced. The value of reduces the regulation intensity of the energy storage SVG.

[0046] and The value of can be adjusted according to the frequency stability requirements of the power grid to ensure that when the frequency deviation is small, the energy storage SVG will not over-respond and maintain the stability of frequency regulation. For example, when the power grid frequency stability requirements are high, the value of can be appropriately reduced. To avoid frequent adjustments of SVG when the frequency fluctuates slightly, thus protecting the energy storage SVG and extending its service life. On the contrary, if the grid has a high tolerance for frequency fluctuations, or if the energy storage SVG needs to intervene in the adjustment when the frequency deviation is small, it can be appropriately increased. The value of enables the energy storage SVG to provide a certain regulation capability when the frequency deviation is small. Through this flexible parameter adjustment, the energy storage SVG can better adapt to the operating status of the power grid and achieve precise control of the power grid frequency.

[0047] In addition, by adjusting the scaling factor α in the Logistic function, the response speed and adjustment accuracy of the energy storage type SVG can be further optimized. The value range is: 5-20. When the α value is larger, the function curve is steeper, the energy storage type SVG responds faster to the frequency deviation, and the regulation accuracy is higher; conversely, the smaller the α value is, the flatter the curve is, and the response speed and regulation accuracy of the energy storage type SVG are relatively low. Therefore, the selection of the α value needs to be comprehensively considered based on the dynamic characteristics of the power grid and the performance of the energy storage type SVG.

[0048] like Figure 3 The droop coefficient curve shown is related to the frequency deviation, where the center point of the droop system regulation is is 50HZ, and this specific frequency deviation is set as the reference frequency, the center point of the adjustment. When the frequency deviation is small, it will be adjusted at a relatively slow response speed according to the characteristics of the Logistic function (i.e., Figure 3 As shown The frequency deviation is defined between 0 and 1 to avoid unnecessary impact on the power grid. As the frequency deviation increases, the output value of the Logistic function increases rapidly, causing the droop coefficient to quickly approach its maximum value (i.e., Figure 3 As shown The preferred value is 10), allowing the energy storage SVG to provide stronger power output to cope with rapid frequency changes. This design ensures that the energy storage SVG can intervene quickly when the frequency deviation is large, and maintain a low regulation intensity when the frequency deviation is small, thereby ensuring the stability of the grid frequency while protecting the energy storage SVG and avoiding possible damage caused by over-regulation. In this way, the energy storage SVG can intelligently adjust its response strategy according to the actual operation of the grid, achieving efficient and precise control of the grid frequency.

[0049] The other details that are the same as those in Embodiment 1 are not described in detail herein.

[0050] Example 4 Figure 4-Figure 5 As shown, the difference from Example 1 is that: in order to further realize the flexible adjustment of the grid-side frequency, the present invention improves the existing energy storage type SVG primary frequency modulation control system. Specifically, the present invention provides an energy storage type SVG primary frequency modulation control system, including an energy storage type SVG1 and a control module 2 electrically connected to the energy storage type SVG1. The control module 2 calculates the real-time frequency deviation through the real-time frequency of the grid side, and calculates the real-time droop coefficient and the primary frequency modulation output power of the energy storage type SVG1 by using the real-time frequency deviation according to the energy storage type SVG primary frequency modulation control method based on the dynamic droop coefficient as shown in any one of Examples 1-3; Further, the control module 2 outputs the primary frequency modulation output frequency to the energy storage type SVG1, and drives the energy storage type SVG1 to adjust the frequency deviation on the grid side; Furthermore, the frequency detection module 3 is electrically connected to the control module 2 , and is used to detect the real-time frequency on the grid side and transmit the real-time frequency to the control module 2 .

[0051] Through the above technical scheme, the energy storage type SVG1 primary frequency modulation control system of the present invention can achieve rapid response and precise control of the grid frequency. The control module 2 can dynamically adjust the output power of the SVG according to the droop coefficient calculated according to the real-time frequency deviation, so as to quickly intervene and adjust when the grid frequency deviates. This real-time frequency adjustment mechanism not only improves the stability of the grid, but also can effectively reduce the frequent start and stop of the SVG and extend the service life of the equipment. In addition, through the cooperation of the real-time frequency detection module 3, the control system can monitor the changes in the grid frequency in real time to ensure the timeliness and accuracy of the frequency modulation control. In practical applications, this system can adapt to the fluctuations of the grid load, effectively alleviate the abnormal fluctuations of the grid frequency, and ensure the stable operation of the grid.

[0052] Furthermore, as a further improvement to the energy storage type SVG1 primary frequency modulation control system of the present invention, the energy storage type SVG1 includes an active power compensation module 11 and a reactive compensation power module, and the active power compensation module and the reactive power compensation module can realize the power four-quadrant operation of the energy storage type SVG1 through decoupling control. Specifically, the active power compensation module 11 is responsible for adjusting the active power output of the energy storage type SVG1 to adapt to the changes in the active power demand of the power grid; the reactive power compensation power module is responsible for adjusting the reactive power output of the energy storage type SVG1 to meet the reactive power demand of the power grid. Through this decoupling control, the energy storage type SVG1 can independently control active and reactive power to achieve more flexible and accurate power grid support.

[0053] For example, during peak load periods of the power grid, the active power compensation module 11 can increase the output power to alleviate the active power shortage of the power grid; and during low load periods of the power grid, the reactive power compensation module 12 can adjust the reactive power output to improve the power factor of the power grid and improve the transmission efficiency of the power grid. In addition, this decoupling control can also reduce the impact of the energy storage type SVG1 on the power grid during the regulation process and improve the stability and reliability of the power grid. In practical applications, this improved energy storage type SVG1 primary frequency regulation control system can better adapt to the dynamic changes of the power grid and provide more stable and efficient frequency support for the power grid.

[0054] Furthermore, the active power compensation module 11 is a supercapacitor module, which is used to provide a frequency modulation output power to the grid side; the reactive compensation power module is at least 2 full-bridge modular multilevel converters; each full-bridge modular multilevel converter can independently perform voltage control and reactive power regulation on the grid side. Among them, the supercapacitor module has the characteristics of fast charging and discharging, and can respond quickly when the grid frequency fluctuates to provide the necessary active power support. Its high power density and long life make it an ideal choice for performing a frequency modulation task. On the other hand, the full-bridge modular multilevel converter (MMC) can achieve fine control of voltage through its multi-level structure, thereby effectively regulating reactive power and improving the power factor of the grid. Each full-bridge modular multilevel converter can be independently controlled, which provides the grid with flexible reactive power regulation capabilities and helps maintain the stable operation of the grid.

[0055] Through the modular design as above, the system of the present invention can flexibly adjust the output of active and reactive power according to the actual needs of the power grid, thereby achieving efficient control of the power grid frequency. In addition, this modular structure is also convenient for the expansion and maintenance of the system, and improves the reliability and adaptability of the entire system. During the operation of the power grid, this energy storage type SVG primary frequency modulation control system can effectively balance the power grid load, reduce frequency deviation, and ensure the stability of the power grid and the quality of power supply.

[0056] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0057] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0058] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0059] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0060] 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, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling primary frequency modulation of energy storage type SVG based on dynamic droop coefficient, characterized in that: The following steps are involved: S101, constructing a primary frequency modulation control equation for an energy storage type SVG, wherein the primary frequency modulation control equation for an energy storage type SVG is used to control the output power of the energy storage type SVG; S201, constructing a dynamic droop coefficient equation through a Logistic function according to the droop external characteristics of the energy storage type SVG, wherein the dynamic droop coefficient equation dynamically adjusts the droop coefficient in the primary frequency modulation control equation of the energy storage type SVG according to the frequency deviation fluctuation in the power grid; S301. Input the frequency deviation of the power grid into the dynamic droop coefficient equation to obtain the real-time droop coefficient and the primary frequency modulation output power of the energy storage type SVG, and the energy storage type SVG performs primary frequency modulation on the power grid according to the primary frequency modulation output power.

2. The energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient according to claim 1 is characterized in that: The dynamic droop coefficient equation in step S201 is: in, is the frequency deviation; is the droop coefficient, which changes with the frequency deviation; is the maximum value of the sag coefficient; is the minimum value of the droop coefficient; is the curve slope adjustment factor in the dynamic droop coefficient equation, controlling the sensitivity of the response; It is the center point of the droop system adjustment, corresponding to a specific frequency deviation.

3. The energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient according to claim 2 is characterized in that: Said The value range is: 5-15; The value range is: 0-1.

4. The energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient according to claim 2 is characterized in that: Said The value range is: 5-20.

5. The energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient according to claim 1 is characterized in that: The process of the power grid performing a frequency modulation in step S301 is based on the frequency change amount. and frequency change rate The two indicators divide the process of energy storage SVG participating in primary frequency modulation into three stages: The first stage is to meet and , at this time, the frequency deviation does not exceed the dead zone threshold, and only a slight correction of the frequency deviation is required by the energy storage SVG; The second stage is to satisfy and At this time, the frequency deviation is large and deteriorates seriously, and the energy storage SVG begins to intervene on a large scale to adjust the frequency deviation; The third stage is to satisfy , at this time, the frequency deviation gradually decreases, and the energy storage type SVG begins to gradually reduce the adjustment of the frequency deviation; in, is the dead zone threshold.

6. The energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient according to claim 1 is characterized in that: The primary frequency modulation control equation of the energy storage type SVG is: in, is the output power of the energy storage type SVG; is the initial output power of the energy storage type SVG; is the droop coefficient, which changes with the frequency deviation; is the frequency deviation.

7. The energy storage type SVG primary frequency modulation control method based on dynamic droop coefficient according to claim 6 is characterized in that: The energy storage type SVG primary frequency modulation control equation is 0.

8. An energy storage type SVG primary frequency modulation control system, characterized in that: It comprises an energy storage type SVG and a control module electrically connected to the energy storage type SVG, wherein the control module calculates a real-time frequency deviation through a real-time frequency calculation on the grid side, and calculates a real-time droop coefficient and a primary frequency modulation output power of the energy storage type SVG through the real-time frequency deviation according to the energy storage type SVG primary frequency modulation control method based on a dynamic droop coefficient as claimed in any one of claims 1 to 7; The control module outputs the primary frequency modulation output frequency to the energy storage type SVG, and drives the energy storage type SVG to adjust the frequency deviation on the grid side; The frequency detection module is electrically connected to the control module, and is used to detect the real-time frequency of the power grid side and transmit the real-time frequency to the control module.

9. The energy storage type SVG primary frequency modulation control system according to claim 8, characterized in that: The energy storage type SVG comprises an active power compensation module and a reactive power compensation module. The active power compensation module and the reactive power compensation module can realize the power four-quadrant operation of the energy storage type SVG through decoupling control.

10. The energy storage type SVG primary frequency modulation control system according to claim 9, characterized in that: The active power compensation module is a supercapacitor module, which is used to provide primary frequency modulation output power to the grid side; The reactive power compensation power module is at least two full-bridge modular multilevel converters; each of the full-bridge modular multilevel converters can independently perform voltage control and reactive power regulation on the grid side.

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