A microgrid multi-source coordinated control method, device, apparatus and system

Abstract

The present application relates to the field of microgrid control technology, and specifically to a microgrid multi-source coordinated control method, equipment, device and system, the method comprising: determining the energy storage utilization of each type of distributed power generation unit at each acquisition moment based on the output voltage of each type of distributed power generation unit at each acquisition moment and the intensity of the coordinated power generation; determining the energy storage imbalance of each energy storage unit at each acquisition moment based on the downward trend of all stored electricity of each energy storage unit and the discrete degree of all output voltages; determining the coordination stability of the microgrid based on the energy storage utilization and the energy storage imbalance, and regulating the microgrid grid-connected operation mode. The present application improves the accuracy of the switching control of the microgrid operation mode by analyzing the coordination between different distributed power generation units and energy storage units during the microgrid grid-connected operation.

Description

Technical Field

[0001] The present application relates to the field of microgrid control technology, and in particular to a microgrid multi-source coordinated control method, equipment, device and system. Background Art

[0002] Microgrids are usually composed of distributed power sources, such as distributed photovoltaics, distributed wind power, gas turbines, etc., as well as load units, energy storage devices, control systems, etc. It is a new type of power network with independent management, protection, and control capabilities. It has good compatibility and wide acceptance of renewable energy. Microgrids have become an ideal way to consume renewable energy with their many advantages and have received widespread attention. At present, the structure of microgrids is mainly divided into centralized control structure and distributed control structure. In the distributed control structure, different microgrid energy managers are relatively independent. If you want to achieve systematic operation of the microgrid, you need to coordinate with each other and jointly participate in the task of energy control management.

[0003] However, the existing methods for smoothly switching the microgrid operation mode, in most cases, only realize the switching control of the microgrid operation mode based on the change of the DC bus voltage, but lack consideration of the coordination between different distributed power generation units and energy storage units, which reduces the accuracy of the switching control of the microgrid operation mode. Summary of the invention

[0004] In a first aspect, an embodiment of the present application provides a microgrid multi-source coordinated control method, the method comprising the following steps:

[0005] Within a preset time, obtain the output voltage and environmental information data of each type of distributed generation unit at all collection times in the microgrid grid-connected operation mode, as well as the storage power and output voltage of each energy storage unit at all collection times;

[0006] In the neighborhood of each collection time, based on the correlation degree of all environmental information data between different distributed power generation units, the cooperative power generation characteristic value of the microgrid at each collection time is determined, and combined with all environmental information data of each type of distributed power generation unit, the cooperative power generation intensity of the microgrid at each collection time is determined; based on the output voltage of each type of distributed power generation unit at each collection time and the cooperative power generation intensity, the energy storage utilization of each type of distributed power generation unit at each collection time is determined;

[0007] In the neighborhood of each collection time, based on the discreteness of all output voltages of each energy storage unit and the downward trend of all stored electricity, the energy storage imbalance degree of each energy storage unit at each collection time is determined;

[0008] Based on the average distribution of energy storage utilization of all distributed generation units at each acquisition moment and the average distribution of energy storage imbalance of all energy storage units, the coordination stability of the microgrid is determined and the grid-connected operation mode of the microgrid is regulated.

[0009] Preferably, the expression of the cooperative power generation characteristic value of the microgrid at each acquisition time is: ; In the formula, represents the cooperative power generation characteristic value of the microgrid at the acquisition time i; It represents the mean value of the correlation between the environmental information data of all types of distributed power generation units in the neighborhood at the collection time i; exp( ) represents an exponential function with a natural constant as the base.

[0010] Preferably, the method for determining the coordinated power generation intensity of the microgrid at each collection moment is:

[0011] At each collection moment, the cumulative sum of the normalized values ​​of all environmental information data of each type of distributed power generation unit is analyzed, and the addition result of the cumulative sum of all types of distributed power generation units is determined. The collaborative power generation intensity of each type at each collection moment is the result of the fusion of the collaborative power generation characteristic value at each collection moment and the said addition result.

[0012] Preferably, the energy storage utilization of each type of distributed power generation unit at each collection moment is the ratio of the output voltage of each type of distributed power generation unit at each collection moment to the coordinated power generation intensity.

[0013] Preferably, the method for determining the energy storage imbalance degree of each energy storage unit at each acquisition moment is:

[0014] All the stored electricity of each energy storage unit in the neighborhood at each acquisition time is used as the input of the time series decomposition algorithm, and the trend sequence of each energy storage unit at each acquisition time is output. The ratio of the number of all negative elements in the first-order difference sequence of the trend sequence to the number of all elements is recorded as the electricity attenuation characteristic value of each energy storage unit at each acquisition time;

[0015] The energy storage imbalance degree of the kth energy storage unit at the acquisition time i The expression is: ; In the formula, Indicates the power attenuation characteristic value of the kth energy storage unit at the acquisition time i; represents the discrete degree of all output voltages of the kth energy storage unit in the neighborhood of the acquisition time i; norm( ) represents the normalization function.

[0016] Preferably, the method for determining the coordination stability of the microgrid is:

[0017] Analyze the average value of energy storage utilization of all distributed energy storage units at each collection time, and analyze the average value of energy storage imbalance of all energy storage units at each collection time;

[0018] The ratio of the average value of the energy storage utilization degree to the average value of the energy storage imbalance degree at each collection time is recorded as the coordination effect value at each collection time;

[0019] Coordination and stability of microgrids The expression is: ; In the formula, , They represent the coordination value of the microgrid at the acquisition time i and i-1 respectively; N represents the number of all acquisition times; exp( ) represents an exponential function with a natural constant as the base.

[0020] Preferably, the process of regulating the microgrid grid-connected operation mode is:

[0021] If the coordination stability of the microgrid in the microgrid grid-connected operation mode is less than a preset threshold, the microgrid operation mode is set to an off-grid state; otherwise, the microgrid is adjusted to a grid-connected operation mode.

[0022] In a second aspect, an embodiment of the present application provides a microgrid multi-source coordinated control device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of any one of the above-mentioned microgrid multi-source coordinated control methods when executing the computer program.

[0023] In a third aspect, an embodiment of the present application provides a microgrid multi-source coordinated control device, on which a computer program is stored, and the computer program is used to implement the steps of any one of the microgrid multi-source coordinated control methods described above.

[0024] In a fourth aspect, an embodiment of the present application further provides a microgrid multi-source coordinated control system, the system comprising:

[0025] The microgrid data acquisition module is used to obtain the output voltage and environmental information data of each type of distributed power generation unit at all acquisition times in the microgrid grid-connected operation mode, as well as the storage power and output voltage of each energy storage unit at all acquisition times within a preset time period;

[0026] The microgrid data analysis module is used to determine the cooperative power generation characteristic value of the microgrid at each collection time based on the correlation degree of all environmental information data between different distributed power generation units in the neighborhood at each collection time, and determine the cooperative power generation intensity of the microgrid at each collection time in combination with all environmental information data of each type of distributed power generation unit; based on the output voltage of each type of distributed power generation unit at each collection time and the cooperative power generation intensity, determine the energy storage utilization of each type of distributed power generation unit at each collection time;

[0027] In the neighborhood of each collection time, based on the discreteness of all output voltages of each energy storage unit and the downward trend of all stored electricity, the energy storage imbalance degree of each energy storage unit at each collection time is determined;

[0028] The microgrid control module is used to determine the coordination stability of the microgrid and regulate the microgrid grid-connected operation mode based on the average distribution of energy storage utilization of all distributed power generation units at each collection moment and the average distribution of energy storage imbalance of all energy storage units.

[0029] It can be seen from the above embodiments that the microgrid multi-source coordinated control method provided in the embodiments of the present application has at least the following beneficial effects:

[0030] The present application determines the energy storage utilization of each type of distributed power generation unit at each collection time by analyzing the correlation degree of all environmental information data between different distributed power generation units in the neighborhood at each collection time, as well as all environmental information data of each type of distributed power generation unit, and combining the output voltage of each type of distributed power generation unit. The beneficial effect is that it can reflect the energy storage utilization characteristics of the coordinated power generation between different distributed power generation units, and improve the accuracy of switching control of the microgrid operation mode; the present application determines the energy storage imbalance of each energy storage unit at each collection time by analyzing the downward trend of all stored electricity of each energy storage unit in the neighborhood at each collection time, as well as the discrete degree of all output voltages, and the beneficial effect is that it can reflect the stability of the microgrid operation process; the present application determines the coordination stability of the microgrid based on the energy storage utilization and the energy storage imbalance, and uses the coordination stability to smoothly switch the microgrid operation mode. The beneficial effect is that it avoids the impact on the operation of the microgrid when the coordination between the distributed power generation unit and the energy storage unit in the microgrid is poor, solves the problem of voltage fluctuation in a large range on the DC bus, and improves the accuracy of switching control of the microgrid operation mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 A flowchart of a multi-source coordinated control method for a microgrid provided in one embodiment of the present application;

[0033] Figure 2 A schematic diagram of a power change trend of an energy storage unit provided in one embodiment of the present application;

[0034] Figure 3 A schematic diagram of a coordinated stability extraction process of a microgrid provided in one embodiment of the present application;

[0035] Figure 4 A block diagram of a microgrid multi-source coordinated control system provided for one embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the microgrid multi-source coordinated control method, equipment, device and system proposed in the present application, its specific implementation method, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0037] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0038] The following is a detailed description of a microgrid multi-source coordinated control method, equipment, device and system provided by the present application in conjunction with the accompanying drawings.

[0039] See also Figure 1 , which shows a flowchart of a microgrid multi-source coordinated control method provided by an embodiment of the present application, the method comprising the following steps:

[0040] Step S1: within a preset time period, obtain the output voltage and environmental information data of each type of distributed generation unit at all collection times in the microgrid grid-connected operation mode, as well as the storage power and output voltage of each energy storage unit at all collection times.

[0041] In this embodiment, the microgrid includes multiple distributed power generation units and multiple energy storage units. In the microgrid grid-connected operation mode, the sampling interval is set to T, and the output voltage and environmental information data of various distributed power generation units at all collection times within the preset time length t, and the stored power and output voltage of each energy storage unit at all collection times within the preset time length t are collected through the microgrid information terminal. Among them, different distributed power generation units have different types of collected environmental information data. For example, when the distributed power generation unit is a wind power generation unit, the collected environmental information data is wind speed data, and when the distributed power generation unit is a solar power generation unit, the collected environmental information data is light intensity data.

[0042] It should be noted that the values ​​of the preset time length t and the sampling interval T are manually set. In this embodiment, the value of the preset time length t is 10 minutes, and the value of the sampling interval T is 0.5 seconds. The implementer can also set them according to the specific situation. This embodiment does not impose any special restrictions.

[0043] Step S2: In the neighborhood of each collection time, based on the correlation degree of all environmental information data between different distributed power generation units, determine the collaborative power generation characteristic value of the microgrid at each collection time, and combine all environmental information data of each type of distributed power generation unit to determine the collaborative power generation intensity of the microgrid at each collection time; based on the output voltage of each type of distributed power generation unit at each collection time and the collaborative power generation intensity, determine the energy storage utilization of each type of distributed power generation unit at each collection time.

[0044] Normally, during the renewable energy generation process, due to changes in the suitability of the power generation environment, strong collaborative power generation characteristics may appear. In the state of renewable energy collaborative power generation, distributed power generation units have stronger power generation capabilities, that is, at this time, distributed power generation units can maintain a high level of power generation, and it is necessary to store energy for excess power production in order to provide power for the operation of the microgrid through the microgrid's energy storage unit when renewable energy generation is unstable.

[0045] Therefore, in order to analyze the coordination between different distributed power generation units and energy storage units in the microgrid at each collection time, the neighborhood W is divided with each collection time as the center, where the value of the neighborhood W is artificially set. In this embodiment, the value of the neighborhood W is 60, and the implementer can also set it by himself according to the specific situation. This embodiment does not impose any special restrictions.

[0046] Among different types of distributed generation units, for example, for wind power generation units, the greater the wind speed, the higher the power generation efficiency and power generation of wind power generation; for solar power generation units, the stronger the light intensity, the higher the power generation efficiency and power generation of solar power generation. Therefore, in order to better evaluate the impact of environmental information data on the power generation intensity of distributed generation units, all environmental information data are normalized to eliminate the impact of the environmental information data dimension.

[0047] It should be noted that there are many commonly used data normalization methods. In this embodiment, the z-score normalization method is used to normalize all environmental information data. The implementer can also use other normalization methods such as maximum and minimum value normalization method. This embodiment does not impose any special restrictions on the selection of data normalization method.

[0048] Among them, the z-score normalization method is a well-known technology, and the specific process of normalizing the data is not repeated here.

[0049] Furthermore, in order to more comprehensively evaluate the performance of various distributed generation units in the microgrid, improve the utilization rate of energy storage, and thus determine the operation mode of the microgrid, so as to be able to provide power for the operation of the microgrid through the energy storage unit of the microgrid when the renewable energy generation is unstable, therefore, in the neighborhood of each collection time, by analyzing the correlation degree of all environmental information data between different distributed generation units, and all environmental information data of each type of distributed generation unit, and combining the output voltage of each type of distributed generation unit, the energy storage utilization of the microgrid at each collection time is determined, specifically:

[0050] (1) Based on the correlation degree of all environmental information data between different distributed generation units in the neighborhood at each collection time, the collaborative power generation characteristic value at each collection time is determined.

[0051] The synergy between distributed generation units is a key factor in evaluating the stability and efficiency of the energy system. Therefore, in order to determine the impact of environmental factors on the synergy between different distributed generation units, the synergy generation characteristic value at each collection moment is determined by analyzing the correlation of environmental information data to accurately evaluate the coordination between distributed generation units. Specifically:

[0052] The cooperative power generation characteristic value of the microgrid at the acquisition time i The expression is: ; In the formula, It represents the mean value of the correlation between the environmental information data of all types of distributed power generation units in the neighborhood at the collection time i; exp( ) represents an exponential function with a natural constant as the base.

[0053] It should be noted that, in this embodiment, one implementation method of the correlation degree of environmental information data between all types of distributed power generation units in the neighborhood at each collection time is: analyzing the Pearson correlation coefficient between each type of environmental information sequence composed of environmental information data of different types of distributed power generation units in the neighborhood at each collection time, to measure the correlation degree of environmental information data between different types of distributed power generation units; in actual application, as other implementation methods, the implementer may also adopt other methods for measuring the degree of correlation, such as the Spearman correlation coefficient or the Kendall correlation coefficient. Regarding the selection of the method for measuring the degree of correlation, this embodiment does not impose any special restrictions.

[0054] According to the collaborative power generation characteristic values ​​of the microgrid at each collection moment, it can be understood that when the collaborative power generation characteristics between different distributed power generation units are stronger, that is, the correlation degree of environmental information data between different types of distributed power generation units is greater, including being beneficial to power generation of different distributed power generation units and being unfavorable to power generation of different distributed power sources at the same time, the collaborative power generation characteristic value will increase; conversely, when the collaborative power generation characteristics between different distributed power generation units are weaker, that is, the correlation degree of environmental information data between different types of distributed power generation units is smaller, the collaborative power generation characteristic value is smaller.

[0055] (2) Based on the collaborative power generation characteristic value and all environmental information data of each type of distributed power generation unit in the neighborhood at each collection time, determine the collaborative power generation intensity of the microgrid at each collection time.

[0056] Furthermore, in order to quantify the comprehensive performance and synergy effect of different distributed generation units working together in the microgrid at a specific moment, the coordinated generation intensity of the microgrid at each collection moment is determined based on the coordinated generation characteristic value and all environmental information data of each type of distributed generation unit in the neighborhood at each collection moment, specifically:

[0057] At each collection moment, the cumulative sum of normalized values ​​of all environmental information data of each type of distributed power generation unit is analyzed. For ease of expression, the cumulative sum is recorded as the power generation intensity of each type of distributed power generation unit at each collection moment.

[0058] Further, the addition result of the power generation intensity of all types of distributed power generation units at each collection moment is determined, and the coordinated power generation intensity of the microgrid at each collection moment is the result of the fusion of the coordinated power generation characteristic value of the microgrid at each collection moment and the addition result.

[0059] It should be understood that fusion refers to a method of positively fusing multiple indicators together, and positive fusion refers to combining two or more indicators by adding or multiplying them together in order to obtain a comprehensive indicator, thereby more comprehensively and accurately evaluating a phenomenon or problem. This positive fusion method is not limited to simple arithmetic operations, but can also include more complex statistical models and analysis methods, which can be selected by the implementer according to the specific situation, and this embodiment does not impose any special restrictions.

[0060] Preferably, in the present embodiment, the collaborative power generation intensity of the microgrid at each collection moment is the product of the collaborative power generation characteristic value at each collection moment and the said addition result; in actual application, as other implementation methods, the collaborative power generation intensity of the microgrid at each collection moment is an exponential function value with a natural constant as the base and the sum of the collaborative power generation characteristic value of the microgrid at each collection moment and the said addition result as the independent variable.

[0061] Furthermore, according to the collaborative power generation intensity at each collection moment, it can be understood that the stronger the collaborative power generation feature between different types of distributed power generation units at the current collection moment, that is, the larger the collaborative power generation characteristic value, and the greater the power generation intensity of all types of distributed power generation units, the greater the collaborative power generation intensity of the microgrid at the current collection moment, indicating that the collaborative power generation effect between different distributed power generation units is higher; conversely, the weaker the collaborative power generation feature between different types of distributed power generation units at the current collection moment, that is, the smaller the collaborative power generation characteristic value, and the smaller the power generation intensity of all types of distributed power generation units, the smaller the collaborative power generation intensity of the microgrid at the current collection moment, indicating that the collaborative power generation effect between different distributed power generation units is lower.

[0062] (3) Based on the output voltage of each type of distributed power generation unit at each collection time and the coordinated power generation intensity, determining the energy storage utilization of each type of distributed power generation unit at each collection time.

[0063] Generally speaking, when different distributed generation units have strong synergistic power generation intensity characteristics, it indicates to a certain extent that the ability to generate electricity using renewable energy is strong. However, when the distributed generation units are at a lower output voltage level, it means that renewable energy is not fully utilized. At this time, it is more necessary to smoothly switch the microgrid operation mode to prevent the instability of renewable energy from affecting the stability of the microgrid power supply.

[0064] Therefore, in order to evaluate the utilization efficiency of renewable energy by the energy storage system at a specific moment, thereby ensuring the effective utilization of stored energy and improving the overall energy utilization efficiency, the energy storage utilization of each type of distributed generation unit at each collection moment is determined based on the output voltage of each type of distributed generation unit at each collection moment and the coordinated generation intensity, specifically:

[0065] The energy storage utilization of each type of distributed power generation unit at each collection moment is the ratio of the output voltage of each type of distributed power generation unit at each collection moment to the coordinated power generation intensity.

[0066] Furthermore, according to the energy storage utilization of each type of distributed generation unit at each collection moment, it can be understood that the greater the collaborative power generation intensity at the current collection moment, the stronger the collaborative power generation intensity characteristics between the distributed generation units at the current collection moment, and the smaller the output voltage of the distributed generation unit, to a certain extent, it shows that the utilization rate of renewable energy at the current collection moment is lower, renewable energy is not fully utilized, and the efficiency of energy storage in the energy storage unit is low, then the energy storage utilization is smaller; conversely, the smaller the collaborative power generation intensity at the current collection moment. It means that the collaborative power generation intensity characteristics between the distributed generation units at the current collection moment are weaker, and the larger the output voltage of the distributed generation unit, to a certain extent, it shows that the utilization rate of renewable energy at the current collection moment is higher, renewable energy is fully utilized at the current collection moment, and the efficiency of energy storage in the energy storage unit is high, then the energy storage utilization is greater.

[0067] Step S3: In the neighborhood of each collection time, based on the discreteness of all output voltages of each energy storage unit and the downward trend of all stored electricity, determine the energy storage imbalance degree of each energy storage unit at each collection time.

[0068] Normally, affected by the energy consumption of electronic devices in the microgrid and the power supply and storage of distributed generation units, the energy consumption of electronic devices in the microgrid will lead to a decrease in the stored electricity in the energy storage unit, and the power supply and storage of distributed generation units will lead to an increase in the stored electricity in the energy storage unit. Therefore, during the operation of the microgrid, the electricity in each energy storage unit will generally show a trend of fluctuating changes. If the electricity in the energy storage unit shows a continuous downward trend and the output voltage of the energy storage unit shows a large load change characteristic, it is easy to cause the energy storage unit to have an energy storage imbalance. At this time, it is more necessary to smoothly switch the operation mode of the microgrid in order to ensure the stability and sustainability of the energy in the energy storage unit, thereby avoiding a large range of voltage fluctuations on the DC bus.

[0069] Therefore, in order to monitor whether the energy storage unit is in an unbalanced state and adjust the microgrid operation mode in time, the energy storage imbalance of each energy storage unit at each acquisition time is determined by analyzing the discrete degree of all output voltages of each energy storage unit and the downward trend of all stored electricity in the neighborhood of each acquisition time, so as to prevent the unstable operation of the microgrid, adjust the microgrid operation mode in time, and improve the system stability. Specifically:

[0070] (1) In order to analyze the trend fluctuation of the electricity in the energy storage unit, all the stored electricity of each energy storage unit in the neighborhood at each collection time is used as the input of the time series decomposition algorithm, and the trend sequence of each energy storage unit at each collection time is output.

[0071] It should be noted that there are many commonly used time series decomposition algorithms. In this embodiment, the seasonal trend decomposition algorithm (STL) is used to obtain the electricity trend series. The implementer can also use the SEATS decomposition algorithm to obtain the trend series. This embodiment does not impose any special restrictions on the selection of the time series decomposition algorithm.

[0072] Among them, the seasonal trend decomposition algorithm is a well-known technology, and the specific process of obtaining the electricity trend series will not be repeated here.

[0073] Preferably, the schematic diagram of the power change trend of the energy storage unit provided in this embodiment is as follows: Figure 2 shown.

[0074] (2) Furthermore, in order to extract the power attenuation characteristics of each energy storage unit, the ratio of the number of all negative elements in the first-order difference sequence of the trend sequence of each energy storage unit at each collection time to the number of all elements is recorded as the power attenuation characteristic value of each energy storage unit at each collection time.

[0075] (3) Further, based on the power attenuation characteristic value and the discrete degree of all output voltages of each energy storage unit, the energy storage imbalance degree of each energy storage unit at each collection time is determined, specifically:

[0076] The energy storage imbalance degree of the kth energy storage unit at the acquisition time i The expression is: ; In the formula, Indicates the power attenuation characteristic value of the kth energy storage unit at the acquisition time i; represents the discrete degree of all output voltages of the kth energy storage unit in the neighborhood of the acquisition time i; norm( ) represents the normalization function.

[0077] It should be noted that there are many methods for measuring the degree of discreteness of a set of data. In this embodiment, the degree of discreteness of the output voltage of each energy storage unit is measured by calculating the standard deviation of all output voltages of each energy storage unit in the neighborhood at each acquisition moment. In actual application, the implementer may also use other methods for measuring the degree of discreteness of data, such as variance, mean difference or dispersion coefficient. This embodiment does not impose any special restrictions on the selection of the method for measuring the degree of discreteness of data.

[0078] Furthermore, according to the energy storage imbalance degree of each energy storage unit at each collection moment, it can be understood that the larger the power attenuation characteristic value of the energy storage unit at the current collection moment, and the larger the discrete degree of all output voltages of the energy storage unit in the neighborhood of the current collection moment, the stronger the power decrease trend characteristic in the energy storage unit at the current collection moment, and the larger the load change characteristic presented by the output voltage of the energy storage unit, the more likely it is that energy storage imbalance will occur, and the larger the energy storage imbalance degree of the energy storage unit at the current collection moment; conversely, the smaller the power attenuation characteristic value of the energy storage unit at the current collection moment, and the smaller the discrete degree of all output voltages of the energy storage unit in the neighborhood of the current collection moment, the weaker the power decrease trend characteristic in the energy storage unit at the current collection moment, and the smaller the load change characteristic presented by the output voltage of the energy storage unit, the smaller the energy storage imbalance degree of the energy storage unit at the current collection moment.

[0079] Step S4: Determine the coordination stability of the microgrid based on the average distribution of the energy storage utilization of all distributed generation units at each acquisition moment and the average distribution of the energy storage imbalance of all energy storage units.

[0080] Normally, in the microgrid grid-connected operation mode, the distributed generation units and energy storage units play a coordination role to improve the power support for the grid operation. However, when the coordination role played by the distributed generation units and energy storage units is smaller, it is easier to affect the working state of the DC bus, making the power supply quality and stability of the microgrid lower, so it is more necessary to smoothly switch the microgrid operation mode to ensure the stability of the microgrid operation.

[0081] Therefore, in order to ensure the stability of microgrid operation, based on the average distribution of energy storage utilization of all distributed generation units at each acquisition moment and the average distribution of energy storage imbalance of all energy storage units, the coordination stability of the microgrid is determined, and the operation state of the microgrid is adjusted in time to protect the stability of the microgrid operation process. Specifically:

[0082] Analyze the average energy storage utilization of all distributed energy storage units at each collection time;

[0083] Furthermore, the average value of the energy storage imbalance of all energy storage units at each acquisition time is analyzed;

[0084] Further, the ratio of the average value of the energy storage utilization degree to the average value of the energy storage imbalance degree at each collection time is recorded as the coordination effect value at each collection time;

[0085] Coordination and stability of microgrids The expression is: ; In the formula, Z is the coordination stability of the microgrid; , They represent the coordination value of the microgrid at the acquisition time i and i-1 respectively; N represents the number of all acquisition times; exp( ) represents an exponential function with a natural constant as the base.

[0086] According to the coordination stability of the microgrid, it can be understood that the greater the change between the coordination values ​​at adjacent collection moments, the smaller the coordination stability. To a certain extent, it means that the stability of the coordination between the distributed generation unit and the energy storage unit during the microgrid grid-connected operation mode is worse, which makes it easier for the microgrid to fail and fail to provide continuous, reliable, and high-quality power supply to the microgrid. Therefore, the microgrid operation mode should be switched smoothly. On the contrary, the smaller the change between the coordination values ​​at adjacent collection moments, the greater the coordination stability. To a certain extent, it means that the stability of the coordination between the distributed generation unit and the energy storage unit during the microgrid grid-connected operation mode is better, and the grid-connected operation mode can continue to be adopted.

[0087] Preferably, the schematic diagram of the coordinated stability extraction process of the microgrid provided in this embodiment is as follows: Figure 3 shown.

[0088] Step S5: Based on the coordination stability of the microgrid, the grid-connected operation mode of the microgrid is regulated.

[0089] In order to integrate the coordination between various units in the microgrid, a method for smoothly switching the microgrid operation mode is implemented to avoid voltage fluctuations in a large range on the DC bus. The microgrid operation mode is smoothly switched based on the coordination stability of the microgrid.

[0090] If the coordination stability of the microgrid during the grid-connected operation mode is less than the preset threshold, it means that the stability of the coordination between the distributed power generation unit and the energy storage unit during the grid-connected operation mode is poor, which will cause the microgrid to fail and fail to provide continuous, reliable and high-quality power supply to the microgrid. At this time, the microgrid operation mode is smoothly switched to put the microgrid operation mode in an off-grid state; conversely, if the coordination stability of the microgrid during the grid-connected operation mode is greater than or equal to the preset threshold, it means that the stability of the coordination between the distributed power generation unit and the energy storage unit during the grid-connected operation mode is good, which will not cause the microgrid to fail and can provide continuous, reliable and high-quality power supply to the microgrid. At this time, the operation mode of the microgrid is still the grid-connected operation mode.

[0091] It should be noted that the value of the preset threshold is manually set. In this embodiment, the value of the preset threshold is 0.2. The implementer can also set it by himself according to the specific situation. This embodiment does not impose any special restrictions.

[0092] So far, this embodiment is based on the analysis of the coordinated power generation characteristics between distributed power generation units, and uses the coordinated power generation intensity to construct the energy storage utilization, which reflects the energy storage utilization characteristics during the coordinated power generation between different distributed power generation units, and improves the accuracy of the subsequent switching control of the microgrid operation mode; at the same time, based on the energy storage utilization and combined with the energy storage imbalance characteristics of the energy storage unit, the coordination stability is constructed, and the coordination stability is used to smoothly switch the microgrid operation mode, avoiding the impact on the microgrid operation when the coordination stability between the distributed power generation units and the energy storage units in the microgrid is low, solving the problem of voltage fluctuations in a large range on the DC bus, and improving the accuracy of switching control of the microgrid operation mode.

[0093] Based on the same inventive concept as the above method, an embodiment of the present application also provides a microgrid multi-source coordinated control device, including a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the steps of any one of the above-mentioned microgrid multi-source coordinated control methods are implemented.

[0094] Based on the same inventive concept as the above method, an embodiment of the present application also provides a microgrid multi-source coordinated control device, on which a computer program is stored, and the computer program is used to implement the steps of any one of the above-mentioned microgrid multi-source coordinated control methods.

[0095] Based on the same inventive concept as the above method, the embodiment of the present application also provides a microgrid multi-source coordinated control system, including:

[0096] The microgrid data acquisition module is used to obtain the output voltage and environmental information data of each type of distributed power generation unit at all acquisition times in the microgrid grid-connected operation mode, as well as the storage power and output voltage of each energy storage unit at all acquisition times within a preset time period;

[0097] The microgrid data analysis module is used to determine the cooperative power generation characteristic value of the microgrid at each collection time based on the correlation degree of all environmental information data between different distributed power generation units in the neighborhood at each collection time, and determine the cooperative power generation intensity of the microgrid at each collection time in combination with all environmental information data of each type of distributed power generation unit; based on the output voltage of each type of distributed power generation unit at each collection time and the cooperative power generation intensity, determine the energy storage utilization of each type of distributed power generation unit at each collection time;

[0098] In the neighborhood of each collection time, based on the discreteness of all output voltages of each energy storage unit and the downward trend of all stored electricity, the energy storage imbalance degree of each energy storage unit at each collection time is determined;

[0099] The microgrid control module is used to determine the coordination stability of the microgrid and regulate the microgrid grid-connected operation mode based on the average distribution of energy storage utilization of all distributed power generation units at each collection moment and the average distribution of energy storage imbalance of all energy storage units.

[0100] A block diagram of a microgrid multi-source coordinated control system provided in an embodiment of the present application is as follows: Figure 4 shown.

[0101] It should be noted that the above sequence of the embodiments of the present application is for description only and does not represent the advantages and disadvantages of the embodiments. The above is a description of a specific embodiment of this specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0102] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0103] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application should be included in the protection scope of the present application.

Claims

1. A microgrid multi-source coordinated control method, characterized in that: The method comprises the following steps: Within a preset time, obtain the output voltage and environmental information data of each type of distributed generation unit at all collection times in the microgrid grid-connected operation mode, as well as the storage power and output voltage of each energy storage unit at all collection times; In the neighborhood of each collection time, based on the correlation degree of all environmental information data between different distributed power generation units, the cooperative power generation characteristic value of the microgrid at each collection time is determined, and combined with all environmental information data of each type of distributed power generation unit, the cooperative power generation intensity of the microgrid at each collection time is determined; based on the output voltage of each type of distributed power generation unit at each collection time and the cooperative power generation intensity, the energy storage utilization of each type of distributed power generation unit at each collection time is determined; In the neighborhood of each collection time, based on the discreteness of all output voltages of each energy storage unit and the downward trend of all stored electricity, the energy storage imbalance degree of each energy storage unit at each collection time is determined; Based on the average distribution of energy storage utilization of all distributed generation units at each acquisition moment and the average distribution of energy storage imbalance of all energy storage units, the coordination stability of the microgrid is determined, and the grid-connected operation mode of the microgrid is regulated; The expression of the cooperative power generation characteristic value of the microgrid at each acquisition time is: ; In the formula, represents the cooperative power generation characteristic value of the microgrid at the acquisition time i; represents the mean value of the correlation between the environmental information data of all types of distributed generation units in the neighborhood at the collection time i; exp( ) represents an exponential function with a natural constant as the base; The method for determining the coordinated power generation intensity of the microgrid at each acquisition moment is: At each collection moment, the cumulative sum of the normalized values ​​of all environmental information data of each type of distributed power generation unit is analyzed, and the addition result of the cumulative sums of all types of distributed power generation units is determined, and the coordinated power generation intensity of each type at each collection moment is the result of the fusion of the coordinated power generation characteristic value at each collection moment and the addition result; The energy storage utilization of each type of distributed power generation unit at each collection moment is the ratio of the output voltage of each type of distributed power generation unit at each collection moment to the coordinated power generation intensity; The method for determining the energy storage imbalance degree of each energy storage unit at each acquisition moment is: All the stored electricity of each energy storage unit in the neighborhood at each acquisition time is used as the input of the time series decomposition algorithm, and the trend sequence of each energy storage unit at each acquisition time is output. The ratio of the number of all negative elements in the first-order difference sequence of the trend sequence to the number of all elements is recorded as the electricity attenuation characteristic value of each energy storage unit at each acquisition time; The energy storage imbalance degree of the kth energy storage unit at the acquisition time i The expression is: ; In the formula, Indicates the power attenuation characteristic value of the kth energy storage unit at the acquisition time i; represents the discrete degree of all output voltages of the kth energy storage unit in the neighborhood at the acquisition time i; norm( ) represents the normalization function; The method for determining the coordination stability of the microgrid is: Analyze the average value of energy storage utilization of all distributed energy storage units at each collection time, and analyze the average value of energy storage imbalance of all energy storage units at each collection time; The ratio of the average value of the energy storage utilization degree to the average value of the energy storage imbalance degree at each collection time is recorded as the coordination effect value at each collection time; Coordination and stability of microgrids The expression is: ; In the formula, , Respectively represent the coordination effect value of the microgrid at the acquisition time i and i-1; N represents the number of all acquisition times; exp( ) represents an exponential function with a natural constant as the base; The process of regulating the microgrid grid-connected operation mode is as follows: If the coordination stability of the microgrid in the microgrid grid-connected operation mode is less than a preset threshold, the microgrid operation mode is set to an off-grid state; otherwise, the microgrid is adjusted to a grid-connected operation mode.

2. A microgrid multi-source coordinated control device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the microgrid multi-source coordinated control method as claimed in claim 1 are implemented.

3. A microgrid multi-source coordinated control device, on which a computer program is stored, and the computer program is used to implement the steps of a microgrid multi-source coordinated control method as claimed in claim 1.

4. A microgrid multi-source coordinated control system, implementing a microgrid multi-source coordinated control method as claimed in claim 1, characterized in that: The system comprises: The microgrid data acquisition module is used to obtain the output voltage and environmental information data of each type of distributed power generation unit at all acquisition times in the microgrid grid-connected operation mode, as well as the storage power and output voltage of each energy storage unit at all acquisition times within a preset time period; The microgrid data analysis module is used to determine the cooperative power generation characteristic value of the microgrid at each collection time based on the correlation degree of all environmental information data between different distributed power generation units in the neighborhood at each collection time, and determine the cooperative power generation intensity of the microgrid at each collection time in combination with all environmental information data of each type of distributed power generation unit; based on the output voltage of each type of distributed power generation unit at each collection time and the cooperative power generation intensity, determine the energy storage utilization of each type of distributed power generation unit at each collection time; In the neighborhood of each collection time, based on the discreteness of all output voltages of each energy storage unit and the downward trend of all stored electricity, the energy storage imbalance degree of each energy storage unit at each collection time is determined; The microgrid control module is used to determine the coordination stability of the microgrid and regulate the microgrid grid-connected operation mode based on the average distribution of energy storage utilization of all distributed power generation units at each collection moment and the average distribution of energy storage imbalance of all energy storage units.

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