Optical storage micro-grid off-grid autonomous control method based on adaptive segmented network construction
By adopting an adaptive segmented grid construction strategy, dynamically switching the control modes of energy storage and photovoltaic DC/DC converters, and combining this with orderly switching of load switches, the problem of the lack of integration between the energy storage SOC and the DC bus voltage in the off-grid mode of the microgrid was solved, thus achieving system stability and maximizing the utilization of new energy sources.
Patent Information
- Application Number
- CN202511015029.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-23
- Publication Date
- 2025-10-28
AI Technical Summary
In off-grid mode, existing microgrids face a risk of overall power outages because the energy storage SOC and DC bus voltage are not designed in conjunction with the photovoltaic energy storage routing control strategy, and the load and new energy access cannot be preserved to the maximum extent.
By adopting an adaptive segmented grid construction strategy, the control modes of energy storage and photovoltaic DC/DC converters are dynamically switched, and the load switches are switched on and off in an orderly manner, so as to achieve stable operation of photovoltaic-storage microgrid and maximize the consumption of new energy.
While ensuring system stability, we will retain load and new energy access to the maximum extent possible, reduce the risk of microgrid power outages, and improve power supply reliability and new energy utilization.
Smart Images
Figure CN120855490A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power grid control technology, and in particular to an off-grid autonomous control method for photovoltaic-storage microgrids based on adaptive segmented grid construction. Background Technology
[0002] With the ongoing national energy transition, a large number of distributed renewable energy sources are being connected to the distribution network. Establishing microgrids is a crucial means to improve the utilization rate of distributed renewable energy, enhance power supply reliability, and improve power quality. Due to the volatility and intermittency of distributed renewable energy output, real-time matching of power generation and load within a microgrid is difficult. Power deficits and surpluses within the microgrid can significantly impact system stability, potentially leading to voltage exceeding limits, frequency instability, and equipment damage. In off-grid operation mode, without the distribution network as a backup power source, the rational configuration of energy storage and microgrid autonomous control strategies is essential for real-time power flow balancing and ensuring stable microgrid operation.
[0003] Currently, photovoltaic (PV) energy is the primary renewable energy source connected to low-voltage microgrids. This paper addresses the energy coordination problem in off-grid microgrids by proposing an off-grid autonomous control method for PV-storage microgrids based on adaptive segmented network construction. First, an off-grid AC microgrid structure is designed, dominated by PV and energy storage routers and incorporating other distributed resources. Then, an adaptive segmented network construction strategy for the dominant PV and energy storage routers is proposed: when the energy storage's State of Charge (SOC) has sufficient active power absorption margin, the DC bus voltage is supported by energy storage; when the energy storage SOC approaches saturation, the DC bus voltage is supported by PV. Based on the segmented network construction based on energy storage SOC, the DC bus voltage fluctuation signal is used as the basis for switching between energy storage and PV-supported DC bus modes. Simultaneously, load switches with power detection capabilities are connected to each branch. Based on the average power ranking over a certain period, the switches of each branch are sequentially switched when the energy storage capacity is too high or too low. This minimizes the disconnection of external sources and loads while ensuring stable system operation, maximizing power supply reliability and distributed renewable energy absorption.
[0004] Existing microgrid energy coordination control is divided into centralized control and distributed control, which regulate the active / reactive power output and grid connection mode of distributed resources within the microgrid. However, many current microgrids are supported by a dominant energy storage system or a "new energy-energy storage" energy routing system, allowing users within the microgrid to independently connect to distributed power sources and expand loads. Existing patents do not consider the existence of uncontrollable distributed new energy sources externally, do not combine the energy storage SOC and DC bus voltage segmentation design of photovoltaic-storage energy routing control strategies, and do not incorporate the sequential connection and disconnection of branch lines by load switches. Therefore, when the dominant energy storage or "new energy-energy storage" integrated equipment experiences power overflow or deficit, there is a risk of overall microgrid blackout, and the control algorithm proposed in this invention cannot maximize the preservation of load and new energy access. Summary of the Invention
[0005] This invention provides an off-grid autonomous control method and system for photovoltaic-storage microgrids based on adaptive segmented grid construction, in order to solve some problems existing in the current off-grid autonomous control methods for photovoltaic-storage microgrids.
[0006] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides an off-grid autonomous control method for a photovoltaic-storage microgrid based on adaptive segmented network construction, comprising the following steps: (1) Construct an off-grid AC microgrid system, including a dominant photovoltaic energy storage routing system, a load switch controller, external loads and distributed power sources; the dominant photovoltaic energy storage routing system includes energy storage batteries, photovoltaic panels, photovoltaic DC / DC converters, energy storage DC / DC converters and DC / AC converters; the energy storage batteries and photovoltaic panels are connected to the DC bus through the energy storage DC / DC converter and the photovoltaic DC / DC converter respectively, and the DC / AC converter converts the DC bus power into power frequency AC power output; (2) Based on the state of charge of the energy storage battery and the DC bus voltage fluctuation signal, dynamically switch the control mode of the energy storage DC / DC converter and the photovoltaic DC / DC converter; Energy storage DC / DC converter control mode switching includes: When the energy storage SOC is within the preset range, the energy storage DC / DC converter operates in DC bus voltage regulation control mode; When SOC>SOC max At this time, the energy storage DC / DC converter switches to constant active power control mode and outputs constant power. P bat_ref ; When SOC <SOC min At that time, a system power deficit signal is issued; The control mode switching of the energy storage DC / DC converter is also affected by the DC bus voltage. vdc Constraints, including: like v dc < v dc_low or v dc > v dc_high Immediately exit the constant active power mode and switch to the DC bus voltage regulation control mode; when v dc > v dc_high At the same time, a system power overload signal is triggered synchronously; The control mode switching of the photovoltaic DC / DC converter includes: When SOC≤SOC max At this time, the photovoltaic DC / DC converter operates in MPPT control mode; When SOC>SOC max At this time, the photovoltaic DC / DC converter switches to DC bus voltage regulation control mode, and the photovoltaic output voltage command... v pv_ref satisfy: v pv_ref > k a · v pv_mppt ,in, k a This is the margin coefficient. v pv_mppt The voltage at the MPPT point; (3) Based on the average power ranking of branches detected by the load switch, perform orderly switching: When power is exceeded: Loads are cut off in descending order of active power of the branches until the total power of the remaining branches is ≤0; When power is insufficient: Loads are removed in ascending order of active power of the remaining branches until the total power absorbed by the remaining branches is greater than or equal to the active power of the branches. k 2. P pv ( k 2<1); Among them, the active power of the branch includes active power generated and active power absorbed, with active power generated being positive and active power absorbed being negative; Conditions for power restoration: When SOC remains below SOC n2 Exceeding time T n2 Restore excess resection branches in time; When SOC remains higher than SOC n3 Exceeding time Tn3 The missing resection branch was restored in time.
[0007] Optionally, in step (1), the load switch controller is connected to the load switches of each branch line through a communication link, and the load switches are equipped with active power detection modules.
[0008] Optionally, in step (2), the mode switching of the photovoltaic DC / DC converter is also affected by the DC bus voltage. v dc constraint; like v dc < v dc_low Immediately exit the DC bus voltage regulation mode and switch to MPPT mode; like v dc > v dc_high Then the photovoltaic DC / DC converter is locked until SOC ≤ SOC n1 .
[0009] Optionally, in the load switch switching sequence, the average power of the branch is... P 1~ P n The calculation period is T c Seq, sorted sequence n according to P i The values are generated from largest to smallest, where positive values represent active power emitted by a branch and negative values represent active power absorbed by a branch. The average power is calculated during generation. P i After taking the absolute value, generate the data according to the order from largest to smallest; The resection procedure must ensure SOC (State of Occlusion) max / SOC min The setting value allows for a time margin for the load switch to operate.
[0010] Optionally, in the dominant photovoltaic energy storage routing system, the DC / AC converter always adopts a network control strategy, including droop control or virtual synchronous motor control.
[0011] In a second aspect, embodiments of this application provide an off-grid autonomous control system for a photovoltaic-storage microgrid based on adaptive segmented network construction, used to implement any of the methods described in the first aspect, including: The dominant photovoltaic energy storage routing system consists of energy storage batteries, photovoltaic panels, photovoltaic DC / DC converters, energy storage DC / DC converters, and DC / AC converters connected in sequence. At least two branches: connected to the AC bus via load switches, with the branches containing external loads or distributed power sources; Load switch controller: It communicates with the load switch to acquire active power data of each branch in real time and execute switching commands; The load switch integrates an active power detection module, and the detection direction is: when the branch outputs active power. P i >0, when active power is absorbed P i <0.
[0012] Beneficial effects: This invention provides an off-grid autonomous control method for photovoltaic-storage microgrids based on adaptive segmented network architecture. It considers the autonomous access of distributed renewable energy sources and loads to a microgrid supported by a dominant energy storage system or a "new energy-storage" energy routing system, addressing the issue of uncontrollable external users accessing distributed renewable energy sources and loads. Under traditional control strategies, off-grid microgrids face the risk of overall outages due to active power surplus / deficit. This invention, by switching the control strategies of each converter within the photovoltaic-storage energy router and controlling the orderly switching of load switches, maximizes the regulatory potential of photovoltaic and energy storage resources, preserving loads and renewable energy access to the greatest extent possible while ensuring the stability of the microgrid system. Attached Figure Description
[0013] Figure 1 This is a diagram of an off-grid AC microgrid structure according to a preferred embodiment of the present invention; Figure 2 These are control block diagrams of various converters according to preferred embodiments of the present invention; Figure 3 One of the simulation diagrams provided for a preferred embodiment of the present invention; Figure 4 The second simulation diagram is provided for a preferred embodiment of the present invention. Detailed Implementation
[0014] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0015] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.
[0016] See Figure 1-2 This application provides an off-grid autonomous control method for a photovoltaic-storage microgrid based on adaptive segmented network construction, comprising the following steps: (1) Construct an off-grid AC microgrid system, including a dominant photovoltaic energy storage routing system, a load switch controller, external loads and distributed power sources; the dominant photovoltaic energy storage routing system includes energy storage batteries, photovoltaic panels, photovoltaic DC / DC converters, energy storage DC / DC converters and DC / AC converters; the energy storage batteries and photovoltaic panels are connected to the DC bus through the energy storage DC / DC converter and the photovoltaic DC / DC converter respectively, and the DC / AC converter converts the DC bus power into power frequency AC power output; (2) Based on the state of charge of the energy storage battery and the DC bus voltage fluctuation signal, dynamically switch the control mode of the energy storage DC / DC converter and the photovoltaic DC / DC converter; Energy storage DC / DC converter control mode switching includes: When the energy storage SOC is within the preset range, the energy storage DC / DC converter operates in DC bus voltage regulation control mode; When SOC>SOC max At this time, the energy storage DC / DC converter switches to constant active power control mode and outputs constant power. P bat_ref ; When SOC <SOC min At that time, a system power deficit signal is issued; The control mode switching of the energy storage DC / DC converter is also affected by the DC bus voltage. v dc Constraints, including: like v dc < v dc_low or v dc > vdc_high Immediately exit the constant active power mode and switch to the DC bus voltage regulation control mode; when v dc > v dc_high At the same time, a system power overload signal is triggered synchronously; The control mode switching of the photovoltaic DC / DC converter includes: When SOC≤SOC max At this time, the photovoltaic DC / DC converter operates in MPPT control mode; When SOC>SOC max At this time, the photovoltaic DC / DC converter switches to DC bus voltage regulation control mode, and the photovoltaic output voltage command... v pv_ref satisfy: v pv_ref > k a · v pv_mppt ,in, k a This is the margin coefficient. v pv_mppt The voltage at the MPPT point; (3) Based on the average power ranking of branches detected by the load switch, perform orderly switching: When power is exceeded: Loads are cut off in descending order of active power of the branches until the total power of the remaining branches is ≤0; When power is insufficient: Loads are removed in ascending order of active power of the remaining branches until the total power absorbed by the remaining branches is greater than or equal to the active power of the branches. k 2. P pv ( k 2<1); Among them, the active power of the branch includes active power generated and active power absorbed, with active power generated being positive and active power absorbed being negative; Conditions for power restoration: When SOC remains below SOC n2 Exceeding time T n2 Restore excess resection branches in time; When SOC remains higher than SOC n3 Exceeding time T n3 The missing resection branch was restored in time.
[0017] Optionally, in step (1), the load switch controller is connected to the load switches of each branch line through a communication link, and the load switches are equipped with active power detection modules.
[0018] Optionally, in step (2), the mode switching of the photovoltaic DC / DC converter is also affected by the DC bus voltage. v dc constraint; like v dc < v dc_low Immediately exit the DC bus voltage regulation mode and switch to MPPT mode; like v dc > v dc_high Then the photovoltaic DC / DC converter is locked until SOC ≤ SOC n1 .
[0019] In the above embodiments, the DC / AC converter always adopts a grid-based control strategy, such as (existing droop and virtual synchronous motor control); based on the energy storage SOC and DC bus voltage fluctuations, the control strategy of switching the energy storage DC / DC converter and the photovoltaic DC / DC converter is used, and the load switch switching is controlled by the branch active power sequence measured by the load switch.
[0020] Specifically, for energy storage batteries and energy storage DC / DC converters: When the SOC of the energy storage battery is lower than the preset upper limit value max And higher than the lower limit SOC min When the energy storage DC / DC converter operates in DC bus voltage regulation control mode, it adopts voltage and current dual closed-loop control, and the DC bus voltage is stabilized by the energy storage battery.
[0021] When the SOC of the energy storage battery is higher than the upper limit SOC max Subsequently, the energy storage DC / DC converter operates in constant active power control mode, controlling the energy storage to output a relatively low constant active power. P bat_ref This causes the SOC of the energy storage battery to decrease slowly until it falls below a preset value. n1 SOC n1 Slightly lower than SOC max The energy storage DC / DC converter exits the constant active power control mode and re-operates in the DC bus voltage regulation control mode. Based on this, the DC bus voltage is monitored. v dc .when v dc The voltage drop is below the lower limit of the DC bus voltage. v dc_low When this happens, the energy storage DC / DC converter immediately exits the constant active power control mode and re-enters the DC bus voltage regulation control mode. v dc Higher than the upper limit of DC bus voltage vdc_high When this happens, the energy storage DC / DC converter immediately exits the constant active power control mode and resumes operation in the DC bus voltage regulation control mode, issuing a system power overload signal and controlling the load switch to sequentially disconnect the active power branches.
[0022] When the SOC of the energy storage battery is lower than the lower limit SOC min Then, a system power deficit signal is issued, controlling the load switch to sequentially disconnect the active power-absorbing branches.
[0023] Specifically, for photovoltaic cells and photovoltaic DC / DC converters: When the SOC of the energy storage battery is lower than the preset upper limit value max When the photovoltaic DC / DC converter operates in Maximum Power Point Tracking (MPPT) control mode, it maximizes the output power by adjusting the output voltage of the photovoltaic cells.
[0024] When the SOC of the energy storage battery is higher than the upper limit SOC max Subsequently, the photovoltaic cells operate in DC bus voltage regulation control mode, stabilizing the DC bus voltage. When the photovoltaic cell output voltage... v pv Less than its MPPT point voltage v pv_mppt At that time, the system is unstable. Therefore, the DC bus voltage regulation control mode must limit the operation of the photovoltaic cells to... v pv Greater than v pv_mppt Within the specified range, the photovoltaic output voltage command v pv_ref As shown in the following formula, where V dcref This is the rated value of the DC bus voltage. Although, v pv_mppt It shifts to the right as light intensity increases and to the left as temperature rises, but the magnitude of the shift is very small. Therefore, the MPPT point voltage under rated operating conditions can be... v pv_mpptN (Or the photovoltaic output voltage under MPPT control before switching to DC bus voltage regulation) multiplied by a certain margin factor. k a ( k a >1), as a guarantee in actual implementation v pv_ref > v pv_mppt The basis. When v dc The voltage drop is below the lower limit of the DC bus voltage. vdc_low When the photovoltaic DC / DC converter exits the DC bus voltage regulation control mode, it re-enters the MPPT control mode. v dc Higher than the upper limit of DC bus voltage v dc_high At this time, the photovoltaic DC / DC converter is locked down, reducing its output power to zero, until the SOC of the energy storage battery falls below the SOC. n1 The photovoltaic DC / DC converter is restarted in MPPT control mode.
[0025] .
[0026] Optionally, in the load switch switching sequence, the average power of the branch is... P 1~ P n The calculation period is T c Seq, sorted sequence n according to P i The values are generated from largest to smallest, where positive values represent active power emitted by a branch and negative values represent active power absorbed by a branch. The average power is calculated during generation. P i After taking the absolute value, generate the data according to the order from largest to smallest; The resection procedure must ensure SOC (State of Occlusion) max / SOC min The setting value allows for a time margin for the load switch to operate.
[0027] Optionally, in the dominant photovoltaic energy storage routing system, the DC / AC converter always adopts a network control strategy, including droop control or virtual synchronous motor control.
[0028] In the above embodiments, the load switch is equipped with a line active power detection module, which can measure the line active power and direction, and upload the active power data to the load switch controller in the microgrid-dominated photovoltaic energy storage routing system.
[0029] Each load switch detects the active power of branch 1 to branch n within a certain time. T c The average power within is P 1. P 2 to P n The value of active power generated is positive, and the value of active power absorbed is negative. The load switch controller... P 1. P 2 to P n Sort the sequence from largest to smallest to obtain the sequence Seq. n .
[0030] When a system power overload signal is received, in order to minimize the number of branches to be disconnected, the load switch controller controls the load switch according to Seq. n Cut off branches from largest to smallest until the sum of the active power of the remaining branches is less than or equal to 0. This continues when the SOC of the energy storage battery remains below the SOC. n2 A certain time T n2 After that (SOC) n2 <SOC n1 The load switch controller controls the load switch to operate and restore power supply to all branch lines.
[0031] When a system power deficit signal is received, in order to minimize the number of branches to be disconnected, the load switch controller controls the load switch according to Seq. n Cut off branches from smallest to largest until the sum of the active power absorbed by the remaining branches equals " k 2* P pv " P pv For a certain period of time T c Average output of photovoltaic cells within the unit k 2 is the margin factor ( k 2<1) Less than or equal to 0. When the SOC of the energy storage battery is consistently higher than the SOC... n3 A certain time T n3 After that (SOC) n3 SOC min The load switch controller controls the load switch to operate and restore power supply to all branch lines.
[0032] Among them, SOC max and SOC max The settings should take into account the time required for the load switch to disconnect the load, and leave a certain margin to prevent the overall collapse of the microgrid due to excess or deficiency of active power during the disconnection process.
[0033] This application also provides an off-grid autonomous control system for a photovoltaic-storage microgrid based on adaptive segmented network construction, used to implement any of the methods described in the first aspect, including: The dominant photovoltaic energy storage routing system consists of energy storage batteries, photovoltaic panels, photovoltaic DC / DC converters, energy storage DC / DC converters, and DC / AC converters connected in sequence. At least two branches: connected to the AC bus via load switches, with the branches containing external loads or distributed power sources; Load switch controller: It communicates with the load switch to acquire active power data of each branch in real time and execute switching commands; The load switch integrates an active power detection module, and the detection direction is: when the branch outputs active power.P i >0, when active power is absorbed P i <0.
[0034] The following provides simulation waveforms of the proposed strategy under varying external branch power for the above embodiments.
[0035] refer to Figure 3 External branches 1, 2, and 3 are connected to the main photovoltaic and energy storage routing system via load switches 1, 2, and 3 respectively, with active power of respectively. P 1. P 2 and P 3. For example Figure 3 As shown, in t One moment ago, the energy storage system still had sufficient active power absorption capacity, leading to the photovoltaic DC / DC converter operating in MPPT control mode and the energy storage DC / DC converter operating in DC bus voltage regulation control mode. Due to the active power redundancy of the entire system, the energy storage battery absorbed additional active power, and the SOC gradually increased. t At moment 1, the energy storage SOC reaches SOC. max The energy storage DC / DC converter switches to constant power control mode, while the photovoltaic DC / DC converter operates in DC bus voltage regulation control mode. The photovoltaic output power decreases, and the system achieves power balance. t At time 2, P 1. Power surge, insufficient active power provided by the internal power supply, DC bus voltage drops below 1. v dc_low The energy storage DC / DC converter switches to DC bus voltage regulation control mode, while the photovoltaic DC / DC converter operates in MPPT control mode, and the energy storage discharges to compensate for the power gap. Then, respectively in t 3 and t At time 4, the output of distributed power sources on branches 2 and 3 surges, resulting in system overcapacity, and the energy storage SOC reaches the SOC. max There is still active power redundancy, causing the DC bus voltage to rise. t At time 5, the DC bus voltage exceeds v dc_high The system issues an over-power signal. Based on the power ranking, the load switch controller controls load switch 3 to disconnect, and the system returns to stability, proving the effectiveness of the proposed strategy.
[0036] like Figure 4 As shown, in t Before 1 minute, the photovoltaic DC / DC converter within the dominant solar-energy storage routing system was operating in MPPT control mode, while the energy storage DC / DC converter was operating in DC bus voltage regulation control mode. Because... P 1.P 2 and P 3. When the sum of absorbed power exceeds the output of the photovoltaic cells within the dominant light and energy storage routing system, the energy storage battery discharges, and the SOC continues to decline. t At moment 1, the energy storage SOC drops to SOC min The system sends a power deficit signal, and based on the power ranking, the load switch controller controls load switch 2 to open, and the system returns to stability, proving the effectiveness of the proposed strategy.
[0037] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A method for off-grid autonomous control of a photovoltaic-storage microgrid based on adaptive segmented network construction, characterized in that, Includes the following steps: (1) Construct an off-grid AC microgrid system, including a dominant photovoltaic energy storage routing system, a load switch controller, external loads and distributed power sources; the dominant photovoltaic energy storage routing system includes energy storage batteries, photovoltaic panels, photovoltaic DC / DC converters, energy storage DC / DC converters and DC / AC converters; the energy storage batteries and photovoltaic panels are connected to the DC bus through the energy storage DC / DC converter and the photovoltaic DC / DC converter respectively, and the DC / AC converter converts the DC bus power into power frequency AC power output; (2) Based on the state of charge of the energy storage battery and the DC bus voltage fluctuation signal, dynamically switch the control mode of the energy storage DC / DC converter and the photovoltaic DC / DC converter; Energy storage DC / DC converter control mode switching includes: When the energy storage SOC is within the preset range, the energy storage DC / DC converter operates in DC bus voltage regulation control mode; When SOC>SOC max At this time, the energy storage DC / DC converter switches to constant active power control mode and outputs constant power. P bat_ref ; When SOC <SOC min At that time, a system power deficit signal is issued; The control mode switching of the energy storage DC / DC converter is also affected by the DC bus voltage. v dc Constraints include: like v dc < v dc_low or v dc > v dc_high Immediately exit the constant active power mode and switch to the DC bus voltage regulation control mode; when v dc > v dc_high At the same time, a system power overload signal is triggered synchronously; The control mode switching of the photovoltaic DC / DC converter includes: When SOC≤SOC max At this time, the photovoltaic DC / DC converter operates in MPPT control mode; When SOC>SOC max At this time, the photovoltaic DC / DC converter switches to DC bus voltage regulation control mode, and the photovoltaic output voltage command... v pv_ref satisfy: v pv_ref > k a · v pv_mppt ,in, k a This is the margin coefficient. v pv_mppt The voltage at the MPPT point; (3) Based on the average power ranking of branches detected by the load switch, perform orderly switching: When power is exceeded: Loads are cut off in descending order of active power of the branches until the total power of the remaining branches is ≤0; When power is insufficient: Loads are removed in ascending order of active power of the remaining branches until the total power absorbed by the remaining branches is greater than or equal to the active power of the branches. k 2· P pv , k 2 < 1; Among them, the active power of the branch includes active power generated and active power absorbed, with active power generated being positive and active power absorbed being negative; Conditions for power restoration: When SOC remains below SOC n2 Exceeding time T n2 Restore excess resection branches in time; When SOC remains higher than SOC n3 Exceeding time T n3 The missing resection branch was restored in time.
2. The off-grid autonomous control method for photovoltaic-storage microgrids based on adaptive segmented network construction according to claim 1, characterized in that, In step (1), the load switch controller is connected to the load switches of each branch line through a communication link, and the load switches are equipped with active power detection modules.
3. The off-grid autonomous control method for photovoltaic-storage microgrids based on adaptive segmented network construction according to claim 1, characterized in that, In step (2), the mode switching of the photovoltaic DC / DC converter is also affected by the DC bus voltage. v dc constraint; like v dc < v dc_low Immediately exit the DC bus voltage regulation mode and switch to MPPT mode; like v dc > v dc_high Then the photovoltaic DC / DC converter is locked until SOC ≤ SOC n1 .
4. The off-grid autonomous control method for photovoltaic-storage microgrids based on adaptive segmented network construction according to claim 1, characterized in that, In the load switch switching sequence, the average power of the branch is... P 1~ P n The calculation period is T c Seq, sorted sequence n according to P i The values are generated from largest to smallest, where positive values represent active power emitted by a branch and negative values represent active power absorbed by a branch. The average power is calculated during generation. P i After taking the absolute value, generate the data according to the order from largest to smallest; The resection procedure must ensure SOC (State of Occlusion) max / SOC min The setting value allows for a time margin for the load switch to operate.
5. The off-grid autonomous control method for photovoltaic-storage microgrids based on adaptive segmented network construction according to claim 1, characterized in that, In the dominant photovoltaic energy storage routing system, the DC / AC converter always adopts a network control strategy, including droop control or virtual synchronous motor control.
6. An off-grid autonomous control system for a photovoltaic-storage microgrid based on adaptive segmented network construction, used to implement the method described in any one of claims 1-5, characterized in that, include: The dominant photovoltaic energy storage routing system consists of energy storage batteries, photovoltaic panels, photovoltaic DC / DC converters, energy storage DC / DC converters, and DC / AC converters connected in sequence. At least two branches: connected to the AC bus via load switches, with the branches containing external loads or distributed power sources; Load switch controller: It communicates with the load switch to acquire active power data of each branch in real time and execute switching commands; The load switch integrates an active power detection module, and the detection direction is: when the branch outputs active power. P i >0, when active power is absorbed P i <0.