Standby power control method and standby power control system

Abstract

The application discloses a standby power control method and a standby power control system. The standby power control system comprises a photovoltaic system, an energy storage system and a household power distribution circuit connected to a power grid. The photovoltaic system and the energy storage system are connected to the household power distribution circuit respectively. The photovoltaic system can independently supply power to loads on the household power distribution circuit, and the energy storage system can independently supply power to the loads. The standby power control method comprises the following steps: acquiring real-time surplus power of the photovoltaic system transmitted to the power grid, wherein the real-time surplus power is equal to power generation power of the photovoltaic system minus power consumption power of the loads; controlling the energy storage system to take power from the household power distribution circuit to charge according to the real-time surplus power; and dynamically adjusting charging power of the energy storage system according to the real-time surplus power. In this way, the application tracks the surplus power of the photovoltaic system in real time and dynamically adjusts the charging power of the energy storage, thereby utilizing the photovoltaic power originally sent back to the power grid to improve the self-generation and self-use rate and avoiding the impact of power fluctuation on the battery.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a backup power control method and a backup power control system. Background Technology

[0002] With the rapid development of the new energy industry, energy storage systems, due to their flexible deployment and plug-and-play characteristics, are widely used in emergency rescue, outdoor operations, and temporary power supply scenarios. Photovoltaic power generation systems, as an important form of clean energy, are often used in conjunction with energy storage systems to achieve energy transfer.

[0003] However, energy storage systems and photovoltaic (PV) systems often operate independently, lacking an effective energy interaction mechanism. When energy storage systems need additional power, they typically rely on manual connection to the mains or a diesel generator, or are limited to charging within their own fixed application scenarios. On the other hand, the output power of PV systems is highly intermittent and fluctuates. Directly connecting the PV output to the energy storage system for charging may lead to unstable charging due to power fluctuations, and could even damage the energy storage batteries. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art. Therefore, this application provides a backup power control method and a backup power control system.

[0005] The present application discloses a backup power control method for an energy storage system, wherein the energy storage system and a photovoltaic system are respectively connected to a household power distribution line, the photovoltaic system is capable of independently supplying power to the loads on the household power distribution line, the energy storage system is capable of independently supplying power to the loads, and the household power distribution line is also connected to the power grid. The method includes: The real-time surplus power delivered by the photovoltaic system to the power grid is obtained, and the real-time surplus power is equal to the power generation of the photovoltaic system minus the power consumption of the load. Based on the real-time surplus power, the energy storage system is controlled to draw power from the household power distribution line for charging. The charging power of the energy storage system is dynamically adjusted based on the real-time surplus power.

[0006] In some implementations, controlling the energy storage system to draw power from the household power distribution line for charging based on the real-time surplus power includes: When the real-time surplus power is greater than the preset charging start threshold, the energy storage system is started to charge.

[0007] In some embodiments, dynamically adjusting the charging power of the energy storage system based on the real-time surplus power includes: During the charging process of the energy storage system at a preset charging power, if the power consumption of the load increases but the increase is less than the preset charging power, the charging power of the energy storage system is adjusted to the difference between the preset charging power and the increase.

[0008] In some embodiments, dynamically adjusting the charging power of the energy storage system based on the real-time surplus power includes: If the power consumption of the load increases and the increase is greater than or equal to the preset charging power during the charging process of the energy storage system at a preset charging power, the charging of the energy storage system shall be stopped.

[0009] In some embodiments, dynamically adjusting the charging power of the energy storage system based on the real-time surplus power includes: During the charging process of the energy storage system at a preset charging power, if the power consumption of the load decreases, the charging power of the energy storage system is increased by the amount of the decrease, and the increased charging power does not exceed the maximum allowable charging power of the energy storage system.

[0010] In some implementations, if the increased charging power exceeds the maximum permissible charging power, the energy storage system charges at the maximum permissible charging power.

[0011] In some implementations, after adjusting the charging power of the energy storage system, the adjusted real-time surplus power is used as the reference power for the next adjustment.

[0012] In some embodiments, obtaining the real-time surplus power delivered by the photovoltaic system to the power grid includes: The real-time surplus power is detected by a power detection unit located at the connection point between the photovoltaic system and the power grid.

[0013] The backup power control system according to the embodiments of this application includes: A photovoltaic system, connected to a household power distribution line, is used to supply power to loads on the household power distribution line and / or feed power to the grid; An energy storage system, connected to the household power distribution line, is used to supply power to the load and / or draw power from the household power distribution line for charging. A power detection unit is installed at the connection point between the photovoltaic system and the power grid to detect the real-time surplus power delivered by the photovoltaic system to the power grid. The energy storage system is communicatively connected to the power detection unit and is configured to execute the control method.

[0014] In some embodiments, the power detection unit is a current transformer clamped at the connection point.

[0015] In some embodiments, the household power distribution line includes a first phase line and a second phase line, the photovoltaic system and the energy storage system are both connected to the first phase line and the second phase line, and the power detection unit is set at the detection points corresponding to the first phase line and the second phase line.

[0016] The backup power control method and energy storage system disclosed in this application acquire the surplus power transmitted by the photovoltaic system to the grid in real time, and control the energy storage system to draw power from the household distribution line for charging based on the surplus power. At the same time, the charging power is dynamically adjusted to achieve real-time matching between the photovoltaic output power and the energy storage charging power. This allows the energy storage charging process to follow the changes in the photovoltaic surplus power, thereby effectively utilizing the abandoned photovoltaic energy that might otherwise be fed back to the grid, significantly improving the self-consumption rate of photovoltaic power generation, and reducing dependence on grid power. Furthermore, since the charging power is dynamically adjusted with the surplus power, it can avoid the impact of drastic fluctuations in photovoltaic power on the energy storage battery, ensuring stable and controllable charging current and voltage, avoiding overcharging or undercharging, and thus ensuring battery safety and extending its cycle life. In addition, since the existing household distribution line is used as the energy interaction channel, there is no need to add a new dedicated charging line, reducing the system transformation cost. At the same time, it enables the photovoltaic and energy storage systems to operate collaboratively in household power consumption scenarios, improving power supply flexibility and energy utilization efficiency.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the backup power control system in some embodiments of this application.

[0019] Figure 2 This is another schematic diagram of the backup power control system in some embodiments of this application.

[0020] Figure 3-8 This is a flowchart illustrating the backup power control method for an energy storage system in certain embodiments of this application.

[0021] Explanation of symbols in the attached drawings: Backup power control system 1000, photovoltaic system 100, photovoltaic panel 101, first inverter 102, energy storage system 200, energy storage battery 201, second inverter 202, first phase line L1, second phase line L2, distribution box 300, power detection unit 400. Detailed Implementation

[0022] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0023] Please see Figure 1 and Figure 2 This application provides a backup power control system 1000, which includes a photovoltaic system 100, an energy storage system 200, and a household power distribution line. The photovoltaic system 100 is connected to the household power distribution line and can independently supply power to the loads on the household power distribution line and / or feed power to the grid. The energy storage system 200 is connected to the household power distribution line and is used to supply power to the loads and / or draw power from the household power distribution line for charging.

[0024] Please see Figure 3 This application also proposes a backup power control method for the aforementioned energy storage system 200, the backup power control method comprising: 01. Obtain the real-time surplus power delivered by the photovoltaic system to the grid. The real-time surplus power is equal to the power generated by the photovoltaic system minus the power consumed by the load. 02. Based on the real-time surplus power, control the energy storage system to draw power from the household power distribution line for charging; 03. Dynamically adjust the charging power of the energy storage system based on the real-time surplus power.

[0025] In the backup power control method and backup power control system 1000 of this application, the surplus power transmitted by the photovoltaic system 100 to the grid in real time is acquired, and the energy storage system 200 is controlled to draw power from the household power distribution line for charging based on the surplus power. At the same time, the charging power is dynamically adjusted, which can realize the real-time matching between the photovoltaic output power and the energy storage charging power. This allows the energy storage charging process to follow the changes in the photovoltaic surplus power, thereby effectively utilizing the abandoned photovoltaic energy that might otherwise be fed back to the grid, significantly improving the self-consumption rate of photovoltaic power generation, and reducing dependence on grid power. Furthermore, since the charging power is dynamically adjusted with the surplus power, the impact of drastic fluctuations in photovoltaic power on the energy storage battery can be avoided, ensuring that the charging current and voltage are stable and controllable, avoiding overcharging or undercharging, thereby ensuring battery safety and extending its cycle life. In addition, since the existing household power distribution line is used as the energy interaction channel, there is no need to add a new dedicated charging line, reducing the system transformation cost. At the same time, the photovoltaic and energy storage systems can achieve coordinated operation in household power consumption scenarios, improving power supply flexibility and energy utilization efficiency.

[0026] Specifically, the backup power control system 1000 includes a grid access terminal, a distribution box 300, a household power distribution line, a photovoltaic system 100, and an energy storage system 200, with all electrical equipment connected in parallel to the household power distribution line.

[0027] The power grid input terminal is connected to the external power grid and then to the distribution box 300 via the main switch. The input terminal of the household power distribution line is connected to the distribution box 300 as a regular power source. The household power distribution line includes a first phase line L1 and a second phase line L2. Household loads (e.g., load 1, load 2... load 6) can be connected in parallel to the first phase line L1 and the second phase line L2 of the household power distribution line. The household power distribution line is responsible for the collection and distribution of electrical energy from various sources (grid or photovoltaic) to various loads and energy storage.

[0028] Please see Figure 2 The photovoltaic system 100 can be an existing rooftop photovoltaic system in a user's home. The photovoltaic system 100 may include photovoltaic panels 101 and a first inverter 102. The photovoltaic panels 101 convert solar energy into electrical energy (direct current). The first inverter 102 is connected to the first phase line L1 and the second phase line L2 of the home's power distribution line, converting the direct current into alternating current (AC) and independently supplying power to the AC loads on the home's power distribution line. The first inverter 102 can be composed of micro-inverters. The photovoltaic panels 101 receive sunlight and output direct current based on the photovoltaic effect. The micro-inverters are configured for one or more photovoltaic panels 101, locally converting the direct current generated by the photovoltaic panels 101 into AC power suitable for the household loads. This eliminates the need for a centralized combiner inverter structure, allowing for the independent conversion of power from a single photovoltaic module.

[0029] Energy storage system 200 serves as an energy buffer and storage unit. It can be a consumer-grade energy storage system, targeting residential, balcony, outdoor, and small-scale commercial and industrial applications. It features high integration, easy installation, and quiet operation. Energy storage system 200 connects to the household power distribution line and can operate in grid-connected mode to independently power loads via the household power distribution line. For example, in the event of a grid outage, energy storage system 200 can power loads independently via the household power distribution line, or it can share power with the grid to power loads. For instance, if a high-power load is connected to the household power distribution line and the grid is insufficient to supply it, energy storage system 200 can share power with the grid to supply the high-power load via the household power distribution line. Energy storage system 200 can also draw power from the household power distribution line for charging. The power source for energy storage system 200 can be the grid, photovoltaic system 100, or both the grid and photovoltaic system 100.

[0030] like Figure 2As shown, the energy storage system 200 may include an energy storage battery 201 and a second inverter 202. The second inverter 202 and the energy storage battery 201 can be integrated into the same enclosure, relying on natural heat dissipation for thermal management. The heat generated by the second inverter 202 during operation is transferred to the energy storage battery 201 through radiation, convection, and structural conduction, forming a thermal coupling effect. The energy storage system 200 can be connected to the first phase line L1 and the second phase line L2 of the household power distribution line through the second inverter 202. The second inverter 202 can be a bidirectional energy storage converter, which can rectify the AC power from the household power distribution line into DC power in grid-connected mode to charge the energy storage battery 201, and can invert the DC power from the energy storage battery 201 into AC power to feed back to the household power distribution line in off-grid or grid-connected discharge mode to supply power to the load or to the grid.

[0031] The photovoltaic system 100 and the energy storage system 200 can work independently without interfering with each other. That is, the photovoltaic system 100 can work independently without the energy storage system 200, and the energy storage system 200 can also work independently without the photovoltaic system 100.

[0032] Furthermore, the energy storage system 200 can be preset with a backup power strategy. The photovoltaic system 100 and the energy storage system 200 can also cooperate with each other to work together. When the energy storage system 200 detects that its own power is less than the preset power (when it needs to be charged) or detects that the photovoltaic system 100 generates surplus power under sufficient sunlight, it can automatically start the backup power strategy to automatically provide backup power, so that all the power generated by the photovoltaic system 100 can be fully utilized to achieve the maximum economic benefits.

[0033] Specifically, the energy storage system 200 may include an energy management controller. When executing a backup power strategy, the energy management controller can first collect the power at the connection point between the photovoltaic system 100 and the grid in real time. When it detects that the power direction is from the photovoltaic side to the grid side, it determines that there is positive power. This positive power value is the real-time surplus power (indicating that there is excess electrical energy). For example, the real-time power output from the photovoltaic system 100 to the grid side is denoted as Pct_curr. When Pct_curr is less than 0, it means that the current photovoltaic system 100 has strong sunlight and, in addition to being able to provide all the loads, has excess power energy of the size of |Pct_curr|, i.e., there is surplus power. When Pct_curr is greater than 0, it means that the current photovoltaic system 100 has weak sunlight and the energy of the photovoltaic system 100 is insufficient to provide all the loads below it. It also needs the grid to input electrical energy of Pct_curr. At this time, there is no surplus power.

[0034] Alternatively, the energy management controller can also collect the power generation Ppv of the photovoltaic system 100 and the power consumption Pload of the household load in real time, calculate the difference between the two Psurplus=Ppv-Pload, and obtain the real-time surplus power. When the difference is positive, it indicates that the photovoltaic power is in excess, and when it is negative, it indicates that the power needs to be supplemented from the grid.

[0035] Next, the energy management controller can send a charging enable signal to the second inverter 202 according to the real-time surplus power, thereby controlling the second inverter 202 to switch from standby or discharge mode to rectification charging mode, drawing power from the household power distribution line, and charging the energy storage battery 201 of the energy storage system 200 after AC / DC conversion.

[0036] After charging is enabled, the system enters the dynamic tracking and adjustment phase. Based on the real-time surplus power, the charging power of the energy storage system 200 is dynamically adjusted, ensuring that the second inverter 202 dynamically follows the changes in real-time surplus power. When the real-time surplus power increases due to increased photovoltaic output or decreased load, the actual charging power is increased synchronously. Conversely, when the real-time surplus power decreases due to cloud cover or a sudden increase in load, the actual charging power is decreased synchronously. This ensures that the actual charging power of the energy storage system 200 never exceeds the real-time surplus power, preventing power backflow or grid-based power extraction.

[0037] Please see Figure 2 and Figure 4 In some embodiments, the energy storage system 200 further includes a power detection unit 400, and step 01 includes: 011, Real-time surplus power is detected by a power detection unit installed at the connection point between the photovoltaic system and the power grid.

[0038] Specifically, the power detection unit 400 is set at the detection point corresponding to the first phase line L1 and the second phase line L2, and is used to detect the real-time surplus power transmitted by the photovoltaic system to the household power distribution line. The power detection unit 400 can obtain energy from the first phase line L1 and the second phase line L2 through electromagnetic induction, so as to know whether the photovoltaic system 100 has surplus photovoltaic power generation.

[0039] The power detection unit 400 can be a current transformer-type smart meter, which is characterized by its small size and easy installation. The power detection unit 400 includes a current transformer and a smart meter. The current transformer can be connected to the detection points corresponding to the first phase line L1 and the second phase line L2 to sample the current signals of the mains input / output in real time. The smart meter is electrically connected to the current transformer and calculates the power magnitude and direction at the grid connection interface in real time based on the sampled voltage and current. When the power direction is detected to be flowing from the household distribution line side to the grid side, this represents the real-time surplus power transmitted from the photovoltaic system 100 to the grid. The smart meter communicates with the energy management controller of the energy storage system 200 via wired or wireless communication, uploading this data to the energy management controller of the energy storage system 200.

[0040] For example, the smart meter can communicate with the energy storage system 200 via Wi-Fi, or the energy storage system 200 can obtain the real-time surplus power monitored by the smart meter through local area network communication or cloud-to-cloud connection. Alternatively, the energy storage system 200 and the smart meter can obtain the real-time surplus power monitored by the smart meter through wired communication such as RS485 / CAN.

[0041] Thus, by setting up a power detection unit 400 at the connection point between the photovoltaic system 100 and the grid, real-time direct detection of the power magnitude and direction at the grid connection interface is achieved. Compared with indirect calculation methods (such as separately collecting photovoltaic power generation and load power consumption and then subtracting them), this avoids calculation errors caused by asynchronous sampling, sensor accuracy differences, or accumulated communication delays, effectively improving the accuracy and real-time response of surplus power data. At the same time, since the detection location is on the energy convergence bus, the measured data naturally integrates the dynamic balance results of photovoltaic output and load consumption, eliminating the need to acquire independent data from the first inverter 102 and each load branch. This simplifies the system communication topology and data processing logic, reducing system complexity and implementation costs.

[0042] Please see Figure 5 In some implementations, step 02 includes: 021. When the real-time surplus power is greater than the preset charging start threshold, the energy storage system is started to charge.

[0043] It is worth noting that the range of the charging start-up threshold is pre-calibrated based on the lower limit of the rated charging power of the second inverter 202, the minimum allowable charging current of the battery, and the loss characteristics of the household power distribution line. For example, if the charging start-up threshold is set to 50W, it means that when the surplus power delivered by the photovoltaic system 100 to the grid reaches 50W or more, it is determined that there is sufficient absorbable electrical energy, and the conditions for starting charging are met. The charging start-up threshold can be pre-set in the storage unit of the energy management controller, or it can be manually adjusted by the user through the human-machine interface according to actual electricity demand.

[0044] During the automatic backup power process of the energy storage system 200, a preset sampling period (e.g., every 200ms) can be used to obtain the real-time surplus power value and compare it with the charging start threshold. Only after the real-time surplus power is continuously greater than the start threshold for a duration that reaches a preset anti-jitter time (e.g., 5 seconds) is it determined that the start condition is met; otherwise, it continues to maintain standby mode and monitors cyclically. The anti-jitter time can be adaptively adjusted according to the overshoot of the real-time surplus power relative to the threshold.

[0045] Once the startup conditions are met, the energy management controller can send a startup charging command to the bidirectional inverter of the energy storage system 200 via a communication link (such as wired RS485 or wireless Wi-Fi / Bluetooth), causing the second inverter 202 to switch from standby mode to charging mode. After the energy storage system 200 enters the charging state, the startup process is complete.

[0046] In this way, by setting a charging start threshold, the energy storage system 200 only enters the charging state when the photovoltaic surplus power is sufficient, avoiding repeated start-stop due to low surplus power or frequent fluctuations. This eliminates the frequent switching action of the second inverter 202, reduces switching losses and system standby power consumption, and prevents the battery from ineffective cycling in the shallow charge and discharge state, effectively extending the battery cycle life.

[0047] Please see Figure 6 In some implementations, step 03 includes: 031. During the charging process of the energy storage system at the preset charging power, if the power consumption of the load increases but the increase is less than the preset charging power, the charging power of the energy storage system will be adjusted to the difference between the preset charging power and the increase.

[0048] The preset charging power is the target charging power value of the energy storage system 200 in the current control cycle. The preset charging power is determined by the output result of the previous dynamic adjustment cycle, or by the real-time surplus power when the energy storage system 200 just starts charging. For example, the preset charging power can be equal to the real-time surplus power.

[0049] After the energy storage system 200 starts backup power and charges at the preset charging power, if an increase in load power is detected, such as turning on the whole house air conditioner, and the increase in power consumption is less than the current preset charging power, it is determined that the current photovoltaic output power is basically stable, and the increased load power can be made up by reducing the energy storage charging power without drawing power from the grid. At this time, the formula for calculating the adjusted charging power target value is: Pcharge_new=Pcharge_set-ΔPload Where Pcharge_new is the adjusted charging power, Pcharge_set is the preset charging power, and ΔPload is the increase in the load's power consumption.

[0050] The energy management controller encapsulates the calculated final charging power value Pcharge_final into a control command and sends it to the bidirectional converter of the energy storage system 200 via the communication link. After receiving the command, the second inverter 202 adjusts the current loop setpoint on its AC / DC rectifier side to make the actual charging power track the target value, completing one dynamic adjustment cycle.

[0051] In one embodiment, after the energy storage system 200 starts to provide backup power and charges with a charging power of 100W, if the user suddenly turns on the light bulb, the energy storage system 200 will reduce the charging power by 50W accordingly, thereby adjusting the charging power from 100W to 50W.

[0052] In this way, by monitoring changes in load power and dynamically adjusting the energy storage charging power accordingly, the increased load power demand is preferentially met by the surplus photovoltaic power originally used for charging. This achieves an instantaneous balance between load power and energy storage charging power on the household distribution line without starting grid power or increasing the output load of the first inverter 102. This avoids the mains power consumption caused by the grid supplementing the power deficit due to sudden load increases, and also prevents the energy storage charging power from remaining constant during load fluctuations, thus avoiding backflow or reverse current protection actions on the bus. At the same time, since the power adjustment is precisely limited to the preset charging power range, the energy storage system 200 always operates within a safe power range and the adjustment process is smooth and controlled, effectively reducing the current impact on the battery and improving the stability of system operation.

[0053] Please see Figure 7 In some implementations, step 03 further includes: 032. During the charging process of the energy storage system at the preset charging power, if the power consumption of the load increases and the increase is greater than or equal to the preset charging power, the charging of the energy storage system shall be stopped.

[0054] Specifically, the total load power Pload on the household power distribution line can be continuously collected at a fixed sampling period, and the difference in load power between the current moment and the previous moment, ΔPload=Pload(t), can be calculated. Pload(t The difference is calculated as Δt), and this difference is compared in real time with the current preset charging power Pcharge_set of the energy storage system 200. When ΔPload ≥ Pcharge_set, it means that the photovoltaic system 100 no longer has surplus power to charge the energy storage system 200, and the energy storage system 200 stops providing backup power.

[0055] In addition, to enhance the reliability of the judgment, the condition can only be confirmed as true when ΔPload≥Pcharge_set is detected in multiple consecutive sampling cycles (e.g., 3 consecutive times, i.e., for 300ms). This is to filter out false triggers caused by instantaneous load fluctuations.

[0056] In one embodiment, after the energy storage system 200 starts to provide backup power and charges with a charging power of 100W, if the user suddenly turns on a whole-house air conditioner (consuming 2000W), which is greater than the charging power of the energy storage system 200 (100W), then the energy storage system 200 is controlled to shut down charging, thereby stopping the backup power of the energy storage system 200.

[0057] In this way, by detecting when the load power increment reaches or exceeds the current charging power, the energy storage charging is immediately stopped, so that all the electricity generated by the photovoltaic is immediately transferred to the load. In the case of a sudden increase in load, the priority of household electricity supply is ensured, and the bus power drop or power is drawn from the grid is avoided because the charging power and load demand exceed the photovoltaic output.

[0058] Please see Figure 8 In some implementations, step 03 further includes: 033. During the charging process of the energy storage system at a preset charging power, if the power consumption of the load decreases, the charging power of the energy storage system will be increased or decreased by the amount, and the increased charging power will not exceed the maximum allowable charging power of the energy storage system.

[0059] Specifically, after the energy storage system 200 starts to provide backup power and charges at a preset charging power, if a sudden load drop is detected in the photovoltaic system 100, and the photovoltaic system 100 still has surplus power (real-time surplus power) to charge the energy storage system 200, the charging power of the energy storage system 200 can be increased: if the sum of the preset charging power and the real-time surplus power is less than the maximum charging power of the energy storage system 200, the charging power of the energy storage system 200 is adjusted to the sum of the preset charging power and the real-time surplus power; if the sum of the preset charging power and the real-time surplus power is greater than or equal to the maximum charging power of the energy storage system 200, that is, the increased charging power exceeds the maximum allowable charging power, the energy storage system 200 charges at the maximum allowable charging power.

[0060] In addition, after adjusting the charging power of the energy storage system 200, the adjusted charging power will be used as the reference power for the next adjustment.

[0061] In one embodiment, when the energy storage system 200 starts to provide backup power, the power of the photovoltaic system 100 connected to the grid is initially detected to be 100W, and the inverter of the energy storage system 200 is already charging at a charging power of 100W. If the user suddenly turns off the light bulb (adding 50W to the power distribution line), the energy storage system 200 needs to increase the charging power by 50W, adjusting it from 100W to 150W. If the user suddenly turns off the whole house air conditioner (consuming 2000W), and considering the maximum charging power of the energy storage system 200, if the charging power of the energy storage system 200 is 1500W, then only 1500W of power can be installed for backup charging, and the remaining excess power can only flow to the grid.

[0062] In this way, by detecting the reduction in load power consumption and adding the reduction amount to the energy storage charging power, the surplus photovoltaic power released by the load is immediately received and absorbed by the energy storage system 200. This avoids the waste of photovoltaic power originally intended for power supply being fed back to the grid due to load disconnection, thus maximizing the local consumption of photovoltaic power generation during dynamic load fluctuations. At the same time, the increment of charging power is the amount of load reduction, which does not exceed the physical upper limit of the actual surplus power. Furthermore, by setting a maximum allowable charging power clamp, it ensures that the adjustment process is always controlled within the rated boundary of the equipment and the safety current constraint of the battery, avoiding the impact damage to the battery cells and inverter power devices caused by sudden increases in charging current.

[0063] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A backup power control method for an energy storage system, characterized in that, The energy storage system and the photovoltaic system are respectively connected to the household power distribution line. The photovoltaic system can independently supply power to the load on the household power distribution line, and the energy storage system can independently supply power to the load. The household power distribution line is also connected to the power grid. The method includes: The real-time surplus power delivered by the photovoltaic system to the power grid is obtained, and the real-time surplus power is equal to the power generation of the photovoltaic system minus the power consumption of the load. Based on the real-time surplus power, the energy storage system is controlled to draw power from the household power distribution line for charging. The charging power of the energy storage system is dynamically adjusted based on the real-time surplus power.

2. The method according to claim 1, characterized in that, The step of controlling the energy storage system to draw power from the household power distribution line for charging based on the real-time surplus power includes: When the real-time surplus power is greater than the preset charging start threshold, the energy storage system is started to charge.

3. The method according to claim 1, characterized in that, The step of dynamically adjusting the charging power of the energy storage system based on the real-time surplus power includes: During the charging process of the energy storage system at a preset charging power, if the power consumption of the load increases but the increase is less than the preset charging power, the charging power of the energy storage system is adjusted to the difference between the preset charging power and the increase.

4. The method according to claim 1, characterized in that, The step of dynamically adjusting the charging power of the energy storage system based on the real-time surplus power includes: If the power consumption of the load increases and the increase is greater than or equal to the preset charging power during the charging process of the energy storage system at a preset charging power, the charging of the energy storage system shall be stopped.

5. The method according to claim 1, characterized in that, The step of dynamically adjusting the charging power of the energy storage system based on the real-time surplus power includes: During the charging process of the energy storage system at a preset charging power, if the power consumption of the load decreases, the charging power of the energy storage system will be increased or decreased by the amount, and the increased charging power will not exceed the maximum allowable charging power of the energy storage system.

6. The method according to claim 5, characterized in that, If the increased charging power exceeds the maximum allowable charging power, the energy storage system charges at the maximum allowable charging power.

7. The method according to claim 1, characterized in that, After adjusting the charging power of the energy storage system, the adjusted charging power is used as the reference power for the next adjustment.

8. The method according to claim 1, characterized in that, The step of obtaining the real-time surplus power delivered by the photovoltaic system to the power grid includes: The real-time surplus power is detected by a power detection unit located at the connection point between the photovoltaic system and the power grid.

9. A backup power control system, characterized in that, include: A photovoltaic system, connected to a household power distribution line, is used to supply power to loads on the household power distribution line and / or feed power to the grid; An energy storage system, connected to the household power distribution line, is used to supply power to the load and / or draw power from the household power distribution line for charging. A power detection unit is installed at the connection point between the photovoltaic system and the power grid to detect the real-time surplus power delivered by the photovoltaic system to the power grid. The energy storage system is communicatively connected to the power detection unit and is configured to perform the backup power control method according to any one of claims 1 to 8.

10. The backup power control system according to claim 9, characterized in that, The household power distribution line includes a first phase line and a second phase line. The photovoltaic system and the energy storage system are both connected to the first phase line and the second phase line. The power detection unit is set at the detection points corresponding to the first phase line and the second phase line.

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