AC / DC micro-grid energy management method and device

Abstract

The invention discloses an AC / DC micro-grid energy management method and device, relates to the technical field of power systems, and mainly aims to improve the smoothness, stability and reliability of a power grid after an AC / DC micro-grid is accessed. According to the main technical scheme, whether a power failure fault occurs in a main power grid or not is judged; if not, the common coupling point is closed, the micro-grid is controlled to operate in a grid-connected mode, the grid-connected mode is used for representing that the micro-grid maintains stable operation of the main power grid through a cooperative scheduling strategy, and the cooperative scheduling strategy comprises active support of descending fluctuation and peak load shifting or local absorption based on energy storage scheduling constraint; if yes, the common coupling point is disconnected, the micro-grid is controlled to operate in an isolated grid mode, the isolated grid mode is used for representing that the micro-grid maintains self-stable operation through an independent power protection strategy, and the independent power protection strategy comprises self-balancing based on energy storage safety limitation and self-balancing based on energy storage safety limitation. And uninterruptible power supply is carried out on the key power utilization load. The method is used for energy management of the AC / DC micro-grid.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to an AC / DC microgrid energy management method and device. Background Art

[0002] With the increasing global demand for clean energy and the improvement of environmental awareness, distributed energy resources (DERs), such as solar energy, wind energy and other renewable energy power generation systems, have gradually become an important part of the modern power system. At the same time, microgrids, as a small power network that can integrate a variety of distributed power sources and loads, have shown great potential in improving power supply reliability and promoting the consumption of new energy due to their high flexibility and strong adaptability. Low-voltage AC / DC microgrid technology, as an effective strategy to improve the smoothness and stability of the power grid after the access of new energy, can promote the construction of a clean, low-carbon, safe and efficient energy system, especially a new power system with new energy as the main body.

[0003] At present, most microgrid systems in the existing technology have two modes: grid-connected operation and isolated operation. In the grid-connected mode, the microgrid can work with the main grid, and in the event of a fault, it can switch to the isolated mode and operate independently. However, both the grid-connected mode and the isolated mode lack intelligent energy management strategies, that is, in the grid-connected mode, it is difficult to effectively support the frequency and voltage of the main grid to maintain stable operation, and in the isolated mode, it is impossible to ensure the continuous power supply of important loads in the microgrid, which in turn affects the smoothness, stability and reliability of the power grid after the AC / DC microgrid is connected. Summary of the invention

[0004] In view of the above problems, the present application provides an AC / DC microgrid energy management method and device, the main purpose of which is to improve the smoothness, stability and reliability of the AC / DC microgrid after it is connected to the power grid.

[0005] In order to solve the above technical problems, this application proposes the following solutions:

[0006] In a first aspect, the present application provides an AC / DC microgrid energy management method, wherein the microgrid is connected to a main grid via a common coupling point, and the method comprises:

[0007] Determine whether a power outage occurs in the main power grid;

[0008] If not, the common coupling point is closed, and the microgrid is controlled to operate in a grid-connected mode, wherein the grid-connected mode is used to characterize that the microgrid maintains stable operation of the main grid with a coordinated dispatching strategy, wherein the coordinated dispatching strategy includes active support for downward fluctuations, and peak shaving or local consumption based on energy storage dispatch constraints;

[0009] If so, the common coupling point is disconnected and the microgrid is controlled to operate in an isolated grid mode. The isolated grid mode is used to characterize that the microgrid maintains its own stable operation with an independent power protection strategy. The independent power protection strategy includes self-balancing based on energy storage safety limitations and uninterrupted power supply to critical power loads.

[0010] In a second aspect, the present application provides an AC / DC microgrid energy management device, wherein the microgrid is connected to a main grid via a common coupling point, and the device comprises:

[0011] A judgment unit, used to judge whether a power failure occurs in the main power grid;

[0012] a first control unit, configured to close the common coupling point and control the microgrid to operate in a grid-connected mode if the judgment unit determines that no power failure occurs in the main grid, wherein the grid-connected mode is used to characterize that the microgrid maintains stable operation of the main grid with a coordinated dispatching strategy, wherein the coordinated dispatching strategy includes actively supporting downward fluctuations, and performing peak load shaving or local consumption based on energy storage dispatching constraints;

[0013] The second control unit is used to disconnect the common coupling point and control the microgrid to operate in an isolated grid mode if the judgment unit determines that a power outage has occurred in the main grid. The isolated grid mode is used to characterize that the microgrid maintains its own stable operation with an independent power protection strategy. The independent power protection strategy includes self-balancing based on energy storage safety limitations and uninterrupted power supply to key power loads.

[0014] In order to achieve the above-mentioned purpose, according to the third aspect of the present application, a storage medium is provided, which includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the AC / DC microgrid energy management method of the above-mentioned first aspect.

[0015] In order to achieve the above-mentioned purpose, according to a fourth aspect of the present application, a processor is provided, wherein the processor is used to run a program, wherein the program executes the AC / DC microgrid energy management method of the above-mentioned first aspect when running.

[0016] By means of the above technical scheme, the present application provides an AC / DC microgrid energy management method and device. When it is necessary to manage the energy of the AC / DC microgrid, it is first determined whether a power outage occurs in the main grid to determine the real-time operating status of the main grid. If no power outage occurs, it means that the status is normal. At this time, the common coupling point is closed, and the microgrid is controlled to operate in a grid-connected mode, that is, the microgrid maintains stable operation of the main grid with a collaborative scheduling strategy. The collaborative scheduling strategy includes active support for downward fluctuations, and peak shaving and valley filling or local consumption based on energy storage scheduling constraints. If a power outage occurs, it means that the main grid is abnormal. At this time, the common coupling point is disconnected, and the microgrid is controlled to operate in an isolated grid mode, that is, the microgrid maintains its own stable operation with an independent power protection strategy. The independent power protection strategy includes self-balancing based on energy storage safety restrictions, and uninterrupted power supply to key power loads. Through the technical solution provided by this application, when the main grid is operating normally, by closing the common coupling point and adopting a coordinated scheduling strategy, the microgrid can effectively support the frequency and voltage stability of the main grid, including active support for downward fluctuations and peak shaving or local consumption based on energy storage scheduling constraints, thereby enhancing the stability of the entire power system and maximizing the use of renewable energy. When a power outage in the main grid is detected, the closed common coupling point is quickly disconnected and the microgrid is switched to an isolated grid mode. An independent power protection strategy is adopted to ensure continuous power supply to key loads within the microgrid. By performing self-balancing based on energy storage safety restrictions, the risk of overcharging or over-discharging is avoided, and the uninterrupted operation of important facilities is guaranteed, which significantly improves the smoothness, stability and reliability of the power grid after the microgrid is connected. In addition, real-time monitoring and intelligent decision-making mechanisms ensure that the system can respond flexibly under different conditions, achieving smooth switching and stable operation. Overall, it provides strong technical support for building a more intelligent, efficient and reliable new power system.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0019] Figure 1 A flow chart of an AC / DC microgrid energy management method provided in an embodiment of the present application is shown;

[0020] Figure 2 Another flow chart of an AC / DC microgrid energy management method provided by an embodiment of the present application is shown;

[0021] Figure 3 A block diagram of an AC / DC microgrid energy management device provided in an embodiment of the present application is shown;

[0022] Figure 4 A block diagram showing another AC / DC microgrid energy management device provided in an embodiment of the present application is shown;

[0023] Figure 5 A structural schematic diagram of an AC / DC microgrid energy management device provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0024] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0025] At present, most microgrid systems in the existing technology have two modes: grid-connected operation and isolated operation. In the grid-connected mode, the microgrid can work with the main grid, and in the event of a fault, it can switch to the isolated mode and operate independently. However, both the grid-connected mode and the isolated mode lack intelligent energy management strategies, that is, in the grid-connected mode, it is difficult to effectively support the frequency and voltage of the main grid to maintain stable operation, and in the isolated mode, it is impossible to ensure the continuous power supply of important loads in the microgrid, which in turn affects the smoothness, stability and reliability of the power grid after the AC / DC microgrid is connected.

[0026] After research, the inventor found that the state of the main grid can be monitored in real time, and the common coupling point can be closed when the state is normal, so as to support the stable operation of the main grid with a coordinated dispatching strategy, that is, by actively supporting frequency and voltage fluctuations, peak shaving and valley filling based on energy storage dispatching constraints, and local consumption, etc., to enhance the stability of the main grid. When a power outage or other situation occurs and causes an abnormal state, the common coupling point is quickly disconnected and switched to the isolated grid mode, and an independent power protection strategy is adopted to ensure the continuous power supply of key loads within the microgrid, that is, self-balancing based on energy storage safety restrictions, and giving priority to ensuring uninterrupted power supply to key power loads. In this way, the AC / DC microgrid can realize intelligent dispatching and optimized control, thereby significantly improving the smoothness, stability and reliability of the power grid after the AC / DC microgrid is connected.

[0027] Based on the above considerations, the embodiment of the present application provides an AC / DC microgrid energy management method, by which the smoothness, stability and reliability of the power grid after the AC / DC microgrid is connected can be improved. The specific execution steps are as follows: Figure 1 As shown, including:

[0028] 101. Determine whether a power outage occurs in the main power grid.

[0029] It should be noted that, in this embodiment, the microgrid is specifically an AC / DC microgrid, which includes an AC side, a DC side, an AC / DC energy router, and a microgrid energy management system (EMS). Figure 5 As shown in the figure, a 380V AC bus can be designed, which is connected to 200kW rooftop photovoltaic, 500kW ground photovoltaic, 500kW / 2MWh energy storage, and 200kW load as the AC side; a 750V DC bus can be designed, which is connected to 50kW rooftop photovoltaic, 50kW / 100kWh energy storage system, 50kW uninterruptible load, and 250kW electronic load as the DC side; an AC / DC energy router is designed to realize the exchange of energy and information between AC / DC buses. The rated power of the AC / DC energy router is 300kW, which is specifically used for DC side voltage stabilization and auxiliary AC side voltage and frequency. The power rate is regulated; a grid-connected mode is designed for the grid-connected connection between the microgrid and the main grid, that is, the AC side of the microgrid can be connected to the main grid by setting up a microgrid integrated switch and a metering cabinet at the common coupling point (PCC); a microgrid energy management system (EMS) is designed to manage the operation of the AC / DC microgrid, including the grid-connected mode and the isolated grid mode. It mainly includes hardware equipment such as an advanced microgrid controller, a rack server, a central control room workstation and a full-station timing system, as well as software parts such as energy management, protection, and customized strategy development, which are used to realize the functions of dispatching control, monitoring, energy management, data display, and interaction with the upper level of the system.

[0030] In this step, the execution subject is the microgrid energy management system. By deploying sensors, smart meters, and metering cabinets near the common coupling point (PCC), key parameters such as voltage, frequency, and current are collected in real time to monitor the operating status of the main power grid. Advanced fault detection algorithms can be used in combination with historical data and machine learning models to quickly and accurately identify whether there is a power outage or abnormal situation in the main power grid, such as voltage sag, excessive frequency deviation, etc. For example, a series of thresholds corresponding to key parameters are pre-set. When certain key parameters are monitored to exceed these thresholds, the system will trigger an alarm and start further analysis. In order to avoid misjudgment, a multiple verification mechanism is adopted to ensure that the fault is confirmed only when multiple data sources are consistent, that is, the fault is confirmed only when the key parameters that exceed the threshold at the same time reach a certain number or a certain proportion. Primary and secondary parameters can also be set for key parameters, and the fault is confirmed by the number or proportion of primary and secondary parameters. This embodiment does not limit this.

[0031] 102. Close the common coupling point and control the microgrid to operate in grid-connected mode.

[0032] Among them, the grid-connected mode is used to characterize the microgrid to maintain the stable operation of the main power grid with a coordinated dispatching strategy. The coordinated dispatching strategy includes active support for downward fluctuations, as well as peak shaving or local consumption based on energy storage dispatch constraints.

[0033] In this step, once the main grid is confirmed to be operating normally, the energy management system will issue an instruction to close the common coupling point so that the microgrid can be reconnected to or remain connected to the main grid. At this time, the operation mode of the microgrid is the grid-connected mode. The microgrid will determine whether it is necessary to actively support the main grid according to the voltage or frequency fluctuation of the main grid. Specifically, the frequency fluctuation can be achieved through inertia and damping support or through the primary frequency regulation function, while the voltage fluctuation can be achieved through the reactive voltage regulation function. Among them, inertia and damping support refers to the energy storage system in the microgrid immediately adjusting the output power according to the frequency change, simulating the behavior of the traditional synchronous generator, helping to slow down the frequency drop speed and maintain the stability of the system. The primary frequency regulation function refers to responding to the frequency deviation, automatically adjusting the active power output, and quickly restoring the frequency to the rated value. The reactive voltage regulation function refers to the reactive power mainly used to compensate the inductive load (such as motors, transformers, etc.) in the line to offset this effect and help maintain the voltage within a reasonable range. Sufficient reactive power can reduce voltage fluctuations and improve the power supply quality.

[0034] In addition to the downward fluctuations of the main grid, the microgrid may also receive dispatch instructions sent by the main grid based on power generation, load, etc. In order to ensure that the microgrid can operate safely and efficiently in the grid-connected mode and maximize the potential of the energy storage system, a storage dispatch constraint can be set, and a dispatch interval can be set for the remaining power of the energy storage system in the microgrid. By monitoring whether the remaining power is within the dispatch interval, and real-time monitoring whether the charging and discharging power of the energy storage system has reached the limit, the charging and discharging state of the energy storage system can be dynamically adjusted according to the monitoring results to ensure the balance of energy supply and demand within the microgrid. If the remaining power or charging and discharging power of the energy storage system in the microgrid meets the dispatch constraint at this time, it means that the dispatch instruction can be executed. At this time, the microgrid will perform peak shaving and valley filling on the main grid, that is, during the peak power consumption period, the energy storage system releases the stored energy and outputs power to the main grid to relieve the pressure on the main grid, and during the low power consumption period, the energy storage system absorbs excess power for charging to balance the load curve. If the remaining power or charging and discharging power of the energy storage system in the microgrid does not meet its scheduling constraints at this time, it means that the scheduling instruction cannot be executed. In this case, the microgrid will consume the power locally, that is, according to the current state of the energy storage system, it will give priority to consuming the power generated by distributed power sources (such as photovoltaic and wind power) locally, that is, giving priority to local use, so as to reduce the phenomenon of abandoned light and wind and maximize the use of renewable energy.

[0035] It should be noted that when the dispatch constraints are met and the main power grid is subjected to peak load shaving and valley filling, a storage output curve of the energy storage system can be formulated in advance according to the operating status of the main power grid, so that output can be carried out according to the storage output curve to improve the efficiency and accuracy of peak load shaving and valley filling.

[0036] 103. Disconnect the common coupling point and control the microgrid to operate in isolated grid mode.

[0037] Among them, the isolated grid mode is used to characterize the microgrid maintaining its own stable operation with an independent power protection strategy. The independent power protection strategy includes self-balancing based on energy storage safety limitations and uninterrupted power supply to key power loads.

[0038] In this step, when a power failure is detected in the main grid, the energy management system immediately issues an instruction to disconnect the common coupling point and isolate the microgrid from the main grid. At this time, the operation mode of the microgrid is an isolated grid mode. Since there may be power loads on both the AC side or the DC side of the microgrid, the power loads are all powered by the energy storage system in the microgrid. Therefore, the charging and discharging safety of the energy storage system and the maintenance of a high residual power to stably supply the power load are top priorities. In order to avoid extreme situations such as overcharging and over-discharging of the energy storage system, which affect the maintenance of the residual power and its own safety, an energy storage safety limit can be set, and a power protection interval can be set for the residual power. By monitoring whether the residual power is within the power protection interval, and real-time monitoring whether the charging and discharging power of the energy storage system reaches the limit, the charging and discharging state of the energy storage system is dynamically adjusted according to the monitoring results to ensure the balance of energy supply and demand within the microgrid. At the same time, the energy management system can also flexibly adjust the charging and discharging plan according to the residual capacity and load demand of the energy storage system to extend the effective power supply time of the energy storage system.

[0039] In addition, since the power loads themselves have different properties, such as data centers, transportation facilities, industrial production and other power loads are facilities or equipment that have strict requirements for continuous power supply. If the power is cut off, it may cause serious consequences, such as threats to personal safety, economic losses or service interruptions. However, office building lighting, outdoor billboards and other power loads are facilities or equipment that will not cause major impacts even if the power is cut off for a short time. Therefore, the power loads can be identified and classified to determine the different types of power loads, such as critical power loads and non-critical power loads. For critical power loads, ensure that they can get priority power supply under any circumstances, and for non-critical power loads, they can be removed step by step when necessary to save limited energy storage resources, extend the power supply time of the energy storage system, and ensure the continuous operation of critical loads.

[0040] Based on the above Figure 1It can be seen from the implementation method that the present application provides an AC / DC microgrid energy management method. When it is necessary to manage the energy of the AC / DC microgrid, it is first determined whether a power outage occurs in the main grid to determine the real-time operating status of the main grid. If no power outage occurs, it means that the state is normal. At this time, the common coupling point is closed, and the microgrid is controlled to operate in a grid-connected mode, that is, the microgrid maintains stable operation of the main grid with a collaborative scheduling strategy. The collaborative scheduling strategy includes active support for downward fluctuations, and peak shaving and valley filling or local consumption based on energy storage scheduling constraints. If a power outage occurs, it means that the state of the main grid is abnormal. At this time, the common coupling point is disconnected, and the microgrid is controlled to operate in an isolated grid mode, that is, the microgrid maintains its own stable operation with an independent power protection strategy. The independent power protection strategy includes self-balancing based on energy storage safety restrictions and uninterrupted power supply to key power loads. Through the technical solution provided by this application, when the main grid is operating normally, by closing the common coupling point and adopting a coordinated scheduling strategy, the microgrid can effectively support the frequency and voltage stability of the main grid, including active support for downward fluctuations and peak shaving or local consumption based on energy storage scheduling constraints, thereby enhancing the stability of the entire power system and maximizing the use of renewable energy. When a power outage in the main grid is detected, the closed common coupling point is quickly disconnected and the microgrid is switched to an isolated grid mode. An independent power protection strategy is adopted to ensure continuous power supply to key loads within the microgrid. By performing self-balancing based on energy storage safety restrictions, the risk of overcharging or over-discharging is avoided, and the uninterrupted operation of important facilities is guaranteed, which significantly improves the smoothness, stability and reliability of the power grid after the microgrid is connected. In addition, real-time monitoring and intelligent decision-making mechanisms ensure that the system can respond flexibly under different conditions, achieving smooth switching and stable operation. Overall, it provides strong technical support for building a more intelligent, efficient and reliable new power system.

[0041] Further, the preferred embodiment of the present application is in the above Figure 1 Based on this, a detailed description of the process of AC / DC microgrid energy management is given. The specific steps are as follows: Figure 2 As shown, including:

[0042] 201. Determine whether a power outage occurs in the main power grid.

[0043] This step is combined with the description of step 101 in the above method, and the same content is not repeated here. It should be noted that if the main grid does not have a power failure, the microgrid operates in a grid-connected mode, and steps 202-207 are executed at this time. If the main grid has a power failure, the microgrid operates in an isolated grid mode, and steps 208-210 are executed at this time.

[0044] 202. Detect whether an actual voltage drop value of the main power grid is lower than a preset voltage drop threshold value for multiple times within a specified time period, and / or whether an actual frequency drop value of the main power grid is lower than a preset frequency drop threshold value.

[0045] In this step, by deploying sensors, smart meters or metering cabinets near the common coupling point (PCC), key parameters such as voltage and frequency are collected in real time to obtain the actual value of voltage drop and the actual value of frequency drop. The voltage drop threshold and the frequency drop threshold are preset, and the voltage drop threshold and the frequency drop threshold are used to characterize the voltage drop range relative to the rated voltage and the rated frequency drop range under normal operation of the main power grid. For example, the voltage drop threshold is 5% of the rated voltage, and the frequency drop threshold is 0.5Hz, etc. Define a specified time length (such as 1 minute), and count the number of voltage drops during this period. If the actual voltage drop value exceeds the voltage drop threshold for multiple times (such as more than 5 times cumulatively) or for multiple times (more than 3 times in a row) during this time period, it is considered that there is a voltage drop fluctuation in the main power grid. If the actual frequency drop value exceeds the preset drop threshold during this time period, it is considered that there is a frequency drop fluctuation in the main power grid. When one of the two is met, step 203 is executed.

[0046] It should be noted that the voltage drop threshold and the frequency drop threshold can be obtained by analyzing historical data when fluctuations occur in the main power grid using a machine learning model. On this basis, the safety margin can be customized in combination with the security of the power grid to increase the sensitivity to the decline fluctuations, thereby improving the timeliness of the processing of the decline fluctuations in step 203.

[0047] 203. Control the virtual synchronous generator in the microgrid to actively support the main grid.

[0048] Among them, active support includes frequency support for the main grid through inertia support, damping support and primary frequency regulation, as well as voltage support for the main grid through reactive voltage regulation.

[0049] In this step, inertia support specifically refers to the virtual synchronous generator (VSG) simulating the behavior of a traditional synchronous generator. When a frequency drop is detected, the active power output is quickly increased to provide an inertia effect and slow down the frequency drop. Damping support specifically refers to suppressing low-frequency oscillations in the main grid and enhancing the stability of the main grid by adjusting the control parameters of the virtual synchronous generator. Primary frequency regulation specifically refers to the virtual synchronous generator automatically adjusting the active power output according to the frequency deviation, quickly restoring the frequency to the rated value, and ensuring frequency stability. Reactive voltage regulation specifically refers to maintaining the voltage level and improving the power quality by adjusting the reactive power output of the virtual synchronous generator.

[0050] During the inertia support process, the frequency change of the main power grid is monitored in real time, and the frequency deviation Δf=f-f0 is calculated, where f is the current frequency and f0 is the rated frequency. According to the frequency deviation, the inertia coefficient H of the virtual synchronous generator is adjusted. The inertia coefficient determines the rotational inertia simulated by the virtual synchronous generator. A larger inertia coefficient can slow down the frequency drop speed, but it will also prolong the recovery time.

[0051] The specific expression is:

[0052]

[0053] Among them, P inertia is the active power increment provided by the inertial support, and T is the time constant, which is usually set according to the system characteristics.

[0054] During the damping support process, the low-frequency oscillation phenomenon of the main power grid is detected using fast Fourier transform (FFT) or other signal processing techniques, and the damping coefficient (D) of the virtual synchronous generator is adjusted according to the amplitude and frequency of the oscillation. A larger damping coefficient helps to suppress the oscillation faster, but it may increase the response time of the system.

[0055] The specific expression is:

[0056] P damping =D·Δf;

[0057] Among them, P damping is the active power increment provided by the damping support, and Δf is the frequency deviation.

[0058] During the primary frequency regulation process, the upper and lower limits of the frequency deviation are set (such as ±0.5Hz). When the frequency exceeds this range, the primary frequency regulation function is started, and the frequency regulation gain (K) of the virtual synchronous generator is adjusted according to the magnitude of the frequency deviation. A larger frequency regulation gain can restore the frequency to the rated value faster, but too large a gain may lead to over-regulation.

[0059] The specific expression is:

[0060] P primary =K·Δf;

[0061] Among them, P primary is the active power increment provided by the damping support, and Δf is the frequency deviation.

[0062] During the reactive voltage regulation process, the node voltage changes are monitored in real time, and the voltage deviation ΔV=V-V0 is calculated, where V is the current voltage and V0 is the rated voltage. According to the voltage deviation, the reactive power Q output by the VSG is adjusted. Larger reactive power can more effectively increase the voltage level, but excessive reactive power may cause other problems (such as reactive reverse transmission).

[0063] The specific expression is:

[0064] Q=K v ΔV;

[0065] Where Q is the reactive power increment, K v is the voltage regulation factor.

[0066] 204. Prepare the energy storage output curve of the microgrid in advance according to the operating status of the main grid.

[0067] In this step, the energy storage output curve is used to characterize the charging and discharging power and power status of the energy storage system in the microgrid in different time periods, so as to achieve peak shaving and valley filling of the main power grid and local consumption of the microgrid itself. Historical data and weather forecasts can be used to predict the load demand in the future. For renewable energy sources (such as photovoltaics and wind power), their power generation capacity can be predicted in combination with meteorological data. Linear programming, genetic algorithms, etc. are used to comprehensively consider economic and technical constraints to formulate the optimal energy storage output curve. It is used to output according to the energy storage output curve after determining the time point and power level of the energy storage system discharging during peak hours and charging during valley hours.

[0068] 205. Determine whether the energy storage system in the microgrid meets the energy storage constraint conditions.

[0069] Among them, the energy storage constraints include energy storage quantity constraints and energy storage power constraints. The energy storage quantity constraints require that the remaining quantity of the energy storage system in the microgrid is within the preset scheduling range, and the energy storage power constraints require that the charging and discharging power of the energy storage system in the microgrid does not reach the power limit.

[0070] In this step, for the energy storage power constraint condition, a reasonable remaining power range can be defined for the energy storage system of the microgrid as a preset scheduling interval to ensure that the energy storage system operates within a safe working range. The preset scheduling interval can be set according to the specific type of scheduling instructions received by the microgrid from the main grid. When the scheduling instruction is energy storage charging, the upper limit of the scheduling interval is that the remaining power is not higher than 90%, and when the scheduling instruction is energy storage discharging, the lower limit of the scheduling interval is that the remaining power is not less than 10%. That is, the preset scheduling interval is 10%-90%. According to the current remaining power of the energy storage system, the charging and discharging plan of the energy storage system can be flexibly adjusted to keep it within a safe range. If the lower limit or upper limit is exceeded, it is considered that the energy storage power constraint condition is not met, otherwise it is considered that the energy storage power constraint condition is met.

[0071] As for the energy storage power constraint, the maximum charge and discharge power limit (such as ±1MW) can be set according to the rated power of the energy storage system and the equipment safety limit. The charge and discharge power of the energy storage system is monitored in real time to ensure that it does not reach the power limit. Once it is detected that the power is close to or exceeds the limit value, it is considered that the energy storage power constraint is not met, otherwise it is considered that the energy storage frequency constraint is met.

[0072] It should be noted that in this step, when the energy storage quantity constraint condition and the energy storage power constraint condition are met at the same time, the energy storage constraint condition is considered to be met, and step 206 is executed at this time. Otherwise, it is considered that the energy storage constraint condition is not met, and step 207 is executed at this time.

[0073] 206. When the microgrid receives a dispatch instruction from the main grid, the microgrid is controlled to perform peak shaving and valley filling for the main grid according to the energy storage output curve.

[0074] In this step, the dispatching instruction includes the energy storage charging type and the energy storage discharging type. Peak shaving and valley filling is achieved by precisely controlling the charging and discharging operations of the energy storage system. When the dispatching instruction from the main power grid dispatching center is received in real time, the specific peak shaving and valley filling tasks are determined according to the type and content of the dispatching instruction, including energy storage charging, energy storage discharging, time point, power level, etc. Based on the energy storage output curve formulated in step 204, the charging and discharging operations of the energy storage system are precisely controlled to achieve the peak shaving and valley filling goal. In addition, the peak shaving and valley filling effect of the energy storage system can be regularly evaluated to ensure that it functions as expected, and the energy storage output curve can be adjusted according to its effect to optimize future dispatching strategies and improve overall efficiency.

[0075] 207. Control the microgrid for local power consumption.

[0076] In this step, local consumption specifically refers to giving priority to using the electricity generated by distributed power sources (such as photovoltaics and wind power) to meet the local load needs of the microgrid, reduce the phenomenon of abandoned solar and wind power, and maximize the use of renewable energy. Arrange the energy storage system to give priority to absorbing the excess electricity generated by distributed power sources to reduce dependence on the external power grid. Without affecting the quality of power supply, as much renewable energy as possible is consumed to reduce the abandonment rate of solar and wind power. Specifically, according to the current power generation and load conditions, the matching relationship is dynamically adjusted to ensure the balance of power supply and demand. At the same time, combined with the energy storage system and other controllable loads, power resources are flexibly dispatched to improve overall efficiency.

[0077] 208. When the energy storage system in the microgrid is in an overcharge state, a power limit instruction is sent to the photovoltaic inverter in the microgrid to limit the photovoltaic output of the microgrid.

[0078] Among them, the overcharge state is that the charging power of the energy storage system in the microgrid reaches the power limit or the remaining power of the energy storage system in the microgrid is higher than the upper limit of the preset power protection range.

[0079] It should be noted that, since the operation mode of the microgrid is isolated grid mode at this time, it is necessary to maintain self-balance and ensure uninterrupted power supply to key loads. Therefore, in order to prevent the energy storage system from being affected by overcharging or over-discharging and affecting the effective power supply time of key loads to ensure its safe operation, a reasonable remaining power range can be defined for the energy storage system of the microgrid as a preset power protection interval. Compared with the preset scheduling interval, the lower limit of the preset power protection interval should be adjusted to a higher value, such as 40%-90%. At the same time, in combination with the charging and discharging efficiency, the maximum charging and discharging power limit (such as ±1MW) can be set according to the rated power of the energy storage system and the equipment safety limit, and the charging and discharging power of the energy storage system can be monitored in real time to ensure that it does not reach the power limit. Once it is detected that the charging power is close to or exceeds the limit value, or the remaining power of the energy storage system exceeds the upper and lower limits of the preset power protection interval, the energy storage system is considered to be in an overcharged state or an over-discharged state.

[0080] In this step, when the charging power of the energy storage system in the microgrid reaches the power limit or the remaining power of the energy storage system in the microgrid is higher than the upper limit of the preset power protection interval, it is considered to be in an overcharge state and an overcharge alarm can be triggered. The energy management system generates a power limit instruction based on the overcharge alarm and sends the power limit instruction to the photovoltaic inverter to limit the output power of the photovoltaic inverter. In addition, the intensity of the power limit instruction can be flexibly adjusted according to the current state of the energy storage system to ensure that the energy storage system gradually returns to a normal state.

[0081] 209. When the energy storage system in the microgrid is in an over-discharge state, non-critical power loads in the microgrid are cut off to ensure the continuous operation of critical power loads.

[0082] Among them, the over-discharge state is that the discharge power of the energy storage system in the microgrid reaches the power limit or the remaining power of the energy storage system in the microgrid is lower than the lower limit of the preset power protection range.

[0083] Combined with the description in step 208, in this step, when the discharge power of the energy storage system in the microgrid reaches the power limit or the remaining power of the energy storage system in the microgrid is lower than the lower limit of the preset power protection interval, it is considered that it is in an over-discharge state at this time, and an over-discharge alarm can be triggered. The energy management system identifies the types of power loads in the microgrid according to the over-discharge alarm to determine which are critical power loads and which are non-critical power loads. Among them, critical power loads are facilities or equipment that have strict requirements for continuous power supply. If power is cut off, serious consequences may occur, such as threats to personal safety, economic losses or service interruptions, including but not limited to data centers, transportation facilities, industrial production, etc., while non-critical power loads are facilities or equipment that will not cause significant impacts even if power is cut off for a short time, including but not limited to office building lighting, outdoor billboards, etc. The types of power loads in the microgrid can be defined in advance to quickly determine the types of power loads. For non-critical power loads, non-critical power loads can be cut off step by step in priority order according to the remaining power and discharge power of the energy storage system to ensure continuous power supply to critical power loads.

[0084] It should be noted that the specific implementation process of cutting off non-critical power loads in the microgrid to ensure the continuous operation of critical power loads is: obtaining the load type of the power load in the microgrid, the load type includes critical power loads and non-critical power loads; calculating whether the number of non-critical power loads is unique; if so, cutting off the non-critical power loads in the microgrid; if not, cutting off the non-critical power loads in the microgrid step by step according to the preset cutting time and cutting number.

[0085] The load type is predefined according to the power supply sensitivity and operation importance of the power load.

[0086] In this step, for power supply sensitivity, the power-consuming equipment can be classified according to its requirements for power supply stability. For example, medical equipment, data center servers, and other equipment that are very sensitive to voltage fluctuations are classified as critical power loads. For operational importance, the power-consuming equipment can be classified according to its function and its importance to the overall operation. For example, facilities such as hospital operating rooms and airport towers are classified as critical power loads, while office lighting, advertising screens, etc. are classified as non-critical power loads. Establish a load database in the energy management system to record the load type of each power-consuming equipment and its corresponding power supply sensitivity and operational importance. Set an electronic tag or identifier for each power-consuming equipment to facilitate real-time monitoring and management. At the same time, the load classification can be regularly evaluated and updated according to actual conditions to ensure that it meets current operational needs and technical standards, and allow users to manually adjust the load type of certain equipment through the EMS interface to meet special needs.

[0087] Since the number of non-critical power loads may be one or more, before cutting off, the operating status of all power loads in the microgrid can be monitored in real time through smart meters, sensors, metering cabinets, etc., and the number of non-critical power loads currently online can be counted. The statistical results are summarized in the energy management system to generate a list of non-critical power loads, including equipment name, power consumption, location and other information. Check whether the number of non-critical power loads is unique. If there is only one non-critical power load, cut off the load immediately to ensure the continuous operation of the critical power load. If there are multiple non-critical power loads, these loads can be cut off gradually to ensure the continuous operation of the critical power load and minimize interference with users. Specifically, the energy management system generates a cut-off command based on the non-critical power loads specified to be cut off, and sends the cut-off command to the corresponding circuit breaker or switch.

[0088] In the process of step-by-step removal, the removal priority can be set according to the importance and impact range of non-critical power loads. For example, equipment with less impact on production, such as landscape lighting and advertising screens, can be removed first. The time interval for each removal is preset (such as once every 5 minutes) to avoid removing too many loads at one time and causing inconvenience to users. The maximum number of removals is set to prevent excessive removal from affecting normal operations. For example, a maximum of 3 removals are allowed, after which other measures must be taken (such as starting the backup power supply). According to the real-time status of the energy storage system, the number of removals and time intervals can be flexibly adjusted to ensure the stability and economy of the system. At the same time, before each removal, a notification is sent to the affected users through the EMS to inform them of the upcoming operation and the estimated impact time, and to collect user feedback to optimize future removal strategies and improve user experience.

[0089] 210. When the energy storage system in the microgrid is not in an overcharge state or an over-discharge state, the microgrid is controlled to operate normally.

[0090] Combined with the description in step 208, in this step, when the energy storage system in the microgrid is not in an overcharge state or an over-discharge state, it indicates that the energy storage system is in a normal state. It is possible to check whether there is a record of switching non-critical power loads in the past period of time. If so, these loads are gradually restored according to the current state to ensure that the stability of the microgrid and user needs are met. Since the energy management system records each operation of cutting off non-critical power loads in real time, including time, device name, power consumption and other information, and saves it in the database. A reasonable time window (such as the past 24 hours) can be pre-defined for querying and analyzing the load removal records during this period. At the same time, the charging and discharging power and remaining power of the energy storage system are continuously monitored to ensure that it is always in a preset power protection range, such as 40%-90%. Set the non-critical power load recovery conditions, such as only when the state of the energy storage system returns to normal and there is sufficient remaining power (more than 60%) and power margin (less than 90%), consider restoring the cut non-critical load. Specifically, the logic of gradually cutting off non-critical power loads in step 209 can be reversed to gradually restore these loads to avoid restoring too many loads at one time, which may cause excessive pressure on the system.

[0091] Furthermore, as a response to the above Figure 1-2 The implementation of the method embodiment shown in the figure, the embodiment of the present application provides an AC / DC microgrid energy management device, which is used to improve the smoothness, stability and reliability of the power grid after the AC / DC microgrid is connected. The embodiment of the device corresponds to the aforementioned method embodiment. For ease of reading, this embodiment will no longer repeat the details of the aforementioned method embodiment one by one, but it should be clear that the device in this embodiment can correspond to all the contents of the aforementioned method embodiment. Specifically, Figure 3 As shown, the device comprises:

[0092] A judging unit 31 is used to judge whether a power failure occurs in the main power grid;

[0093] A first control unit 32 is configured to close the common coupling point and control the microgrid to operate in a grid-connected mode if the judgment unit determines that the main grid has not experienced a power outage, wherein the grid-connected mode is used to characterize that the microgrid maintains stable operation of the main grid with a coordinated dispatching strategy, wherein the coordinated dispatching strategy includes actively supporting downward fluctuations, and performing peak load shaving or local consumption based on energy storage dispatching constraints;

[0094] The second control unit 33 is used to disconnect the common coupling point and control the microgrid to operate in an isolated grid mode if the judgment unit determines that a power outage has occurred in the main grid. The isolated grid mode is used to characterize that the microgrid maintains its own stable operation with an independent power protection strategy. The independent power protection strategy includes self-balancing based on energy storage safety limitations and uninterrupted power supply to key power loads.

[0095] Further, such as Figure 4 As shown, the first control unit 32 includes:

[0096] A detection module 321 is used to detect whether the actual value of the voltage drop of the main power grid is lower than a preset voltage drop threshold value for multiple times within a specified time period, and / or whether the actual value of the frequency drop of the main power grid is lower than a preset frequency drop threshold value;

[0097] The first control module 322 is used to control the virtual synchronous generator in the microgrid to actively support the main grid if the detection module 321 detects that the actual value of the voltage drop of the main grid is lower than the preset voltage drop threshold for multiple times within a specified time period, and / or the actual value of the frequency drop of the main grid is lower than the preset frequency drop threshold. The active support includes frequency support for the main grid through inertia support, damping support and primary frequency regulation, and voltage support for the main grid through reactive voltage regulation.

[0098] Further, such as Figure 4 As shown, the first control unit 32 includes:

[0099] A determination module 323 is used to formulate the energy storage output curve of the microgrid in advance according to the operating status of the main grid;

[0100] A judgment module 324 is used to judge whether the energy storage system in the microgrid meets the energy storage constraint condition;

[0101] A second control module 325 is used to control the microgrid to perform peak shaving and valley filling for the main grid according to the energy storage output curve obtained by the determination module when the microgrid receives a dispatch instruction from the main grid if the determination module 324 determines that the energy storage system in the microgrid meets the energy storage constraint condition;

[0102] The third control module 326 is used to control the microgrid to perform local energy consumption if the judgment module 325 determines that the energy storage system in the microgrid does not meet the energy storage constraint conditions.

[0103] Further, such as Figure 4 As shown, the device also includes:

[0104] The fourth control module 327 is used to, after the second control module 325, send a power limit instruction to the photovoltaic inverter in the microgrid to limit the photovoltaic output of the microgrid when the energy storage system in the microgrid does not meet the energy storage constraint condition.

[0105] Further, such as Figure 4 As shown, the device also includes:

[0106] The energy storage constraint condition includes an energy storage quantity constraint condition and an energy storage power constraint condition. The energy storage quantity constraint condition is that the remaining quantity of the energy storage system in the microgrid is within a preset scheduling interval, and the energy storage power constraint condition is that the charging and discharging power of the energy storage system in the microgrid does not reach the power limit.

[0107] Further, such as Figure 4 As shown, the second control unit 33 includes:

[0108] The fifth control module 331 is used to send a power limit instruction to the photovoltaic inverter in the microgrid to limit the photovoltaic output of the microgrid when the energy storage system in the microgrid is in an overcharge state, wherein the overcharge state is when the charging power of the energy storage system in the microgrid reaches the power limit or the remaining power of the energy storage system in the microgrid is higher than the upper limit of a preset power protection interval;

[0109] The sixth control module 332 is used to cut off non-critical power loads in the microgrid to ensure the continuous operation of critical power loads when the energy storage system in the microgrid is in an over-discharge state, wherein the discharge power of the energy storage system in the microgrid reaches the power limit or the remaining power of the energy storage system in the microgrid is lower than the lower limit of the preset power protection interval;

[0110] The seventh control module 333 is used to control the microgrid to operate normally when the energy storage system in the microgrid is not in the overcharge state and the over-discharge state.

[0111] Further, such as Figure 4 As shown, the sixth control module 332 is specifically used for:

[0112] Obtaining load types of power loads in the microgrid, wherein the load types include critical power loads and non-critical power loads, and the load types are predefined according to power supply sensitivity and operation importance of the power loads;

[0113] Calculating whether the number of the non-critical power loads is unique;

[0114] If yes, then cutting off non-critical power loads in the microgrid;

[0115] If not, the non-critical power loads in the microgrid are removed step by step according to the preset removal time and removal times.

[0116] Furthermore, an embodiment of the present application further provides a storage medium, wherein the storage medium is used to store a computer program, wherein when the computer program is running, the device where the storage medium is located is controlled to execute the above Figure 1-2 The AC / DC microgrid energy management method described in.

[0117] Furthermore, the embodiment of the present application also provides a processor, the processor is used to run a program, wherein the program executes the above Figure 1-2 The AC / DC microgrid energy management method described in.

[0118] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0119] It is understandable that the related features in the above methods and devices can be referenced to each other. In addition, the "first", "second" and the like in the above embodiments are used to distinguish the embodiments, and do not represent the advantages and disadvantages of the embodiments.

[0120] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0121] The algorithm and display provided herein are not inherently related to any particular computer, virtual system or other device. Various general purpose systems can also be used together with the teachings based on this. According to the above description, it is obvious that the structure required for constructing such systems. In addition, the application is not directed to any specific programming language either. It should be understood that various programming languages ​​can be utilized to realize the content of the application described herein, and the description of the specific language above is for the purpose of disclosing the best mode of implementation of the application.

[0122] In addition, the memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0123] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0124] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes 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 generate 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.

[0125] 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.

[0126] 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. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0127] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0128] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0129] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include transitory media such as modulated data signals and carrier waves.

[0130] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0131] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt 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.) that contain computer-usable program code.

[0132] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. An AC / DC microgrid energy management method, characterized in that: The microgrid is connected to the main grid via a common coupling point, and the method comprises: Determine whether a power outage occurs in the main power grid; If not, the common coupling point is closed, and the microgrid is controlled to operate in a grid-connected mode, wherein the grid-connected mode is used to characterize that the microgrid maintains stable operation of the main grid with a coordinated dispatching strategy, wherein the coordinated dispatching strategy includes active support for downward fluctuations, and peak shaving or local consumption based on energy storage dispatch constraints; If so, the common coupling point is disconnected and the microgrid is controlled to operate in an isolated grid mode. The isolated grid mode is used to characterize that the microgrid maintains its own stable operation with an independent power protection strategy. The independent power protection strategy includes self-balancing based on energy storage safety limitations and uninterrupted power supply to critical power loads.

2. The method according to claim 1, characterized in that Controlling the microgrid to operate in a grid-connected mode, comprising: Detecting whether the actual voltage drop value of the main power grid is lower than a preset voltage drop threshold value for multiple times within a specified time period, and / or whether the actual frequency drop value of the main power grid is lower than a preset frequency drop threshold value; If so, the virtual synchronous generator in the microgrid is controlled to actively support the main grid, wherein the active support includes frequency support for the main grid through inertia support, damping support and primary frequency regulation, and voltage support for the main grid through reactive voltage regulation.

3. The method according to claim 1, characterized in that Controlling the microgrid to operate in a grid-connected mode, comprising: Formulate the energy storage output curve of the microgrid in advance according to the operating status of the main grid; Determining whether the energy storage system in the microgrid meets the energy storage constraint condition; If yes, when the microgrid receives the dispatch instruction from the main grid, the microgrid is controlled to perform peak load shaving and valley filling for the main grid according to the energy storage output curve; If not, the microgrid is controlled to consume the energy locally.

4. The method according to claim 3, characterized in that After controlling the microgrid to perform peak shaving and valley filling for the main grid according to the energy storage output curve, the method further includes: When the energy storage system in the microgrid does not meet the energy storage constraint condition, a power limit instruction is sent to the photovoltaic inverter in the microgrid to limit the photovoltaic output of the microgrid.

5. The method according to any one of claims 3 to 4, characterized in that: The energy storage constraint condition includes an energy storage quantity constraint condition and an energy storage power constraint condition. The energy storage quantity constraint condition is that the remaining quantity of the energy storage system in the microgrid is within a preset scheduling interval, and the energy storage power constraint condition is that the charging and discharging power of the energy storage system in the microgrid does not reach the power limit.

6. The method according to claim 1, characterized in that Controlling the microgrid to operate in an isolated grid mode includes: When the energy storage system in the microgrid is in an overcharge state, a power limit instruction is issued to the photovoltaic inverter in the microgrid to limit the photovoltaic output of the microgrid. The overcharge state is when the charging power of the energy storage system in the microgrid reaches the power limit or the remaining power of the energy storage system in the microgrid is higher than the upper limit of the preset power protection interval; When the energy storage system in the microgrid is in an over-discharge state, non-critical power loads in the microgrid are cut off to ensure that critical power loads continue to operate. The over-discharge state is when the discharge power of the energy storage system in the microgrid reaches the power limit or the remaining power of the energy storage system in the microgrid is lower than the lower limit of the preset power protection interval; When the energy storage system in the microgrid is not in the overcharge state and the over-discharge state, the microgrid is controlled to operate normally.

7. The method according to claim 6, characterized in that Cutting off non-critical power loads in the microgrid to ensure continuous operation of critical power loads includes: Obtaining load types of power loads in the microgrid, wherein the load types include critical power loads and non-critical power loads, and the load types are predefined according to power supply sensitivity and operation importance of the power loads; Calculating whether the number of the non-critical power loads is unique; If yes, then cutting off non-critical power loads in the microgrid; If not, the non-critical power loads in the microgrid are removed step by step according to the preset removal time and removal times.

8. An AC / DC microgrid energy management device, characterized in that: The microgrid is connected to the main grid via a common coupling point, and the device comprises: A judgment unit, used to judge whether a power failure occurs in the main power grid; a first control unit, configured to close the common coupling point and control the microgrid to operate in a grid-connected mode if the judgment unit determines that no power failure occurs in the main grid, wherein the grid-connected mode is used to characterize that the microgrid maintains stable operation of the main grid with a coordinated dispatching strategy, wherein the coordinated dispatching strategy includes actively supporting downward fluctuations, and performing peak load shaving or local consumption based on energy storage dispatching constraints; The second control unit is used to disconnect the common coupling point and control the microgrid to operate in an isolated grid mode if the judgment unit determines that a power outage has occurred in the main grid. The isolated grid mode is used to characterize that the microgrid maintains its own stable operation with an independent power protection strategy. The independent power protection strategy includes self-balancing based on energy storage safety limitations and uninterrupted power supply to key power loads.

9. A storage medium, characterized in that: The storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the AC / DC microgrid energy management method according to any one of claims 1 to 7.

10. A processor, characterized in that: The processor is used to run a program, wherein the program, when running, executes the AC / DC microgrid energy management method according to any one of claims 1 to 7.

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