Photovoltaic energy storage charging and discharging control method, device and equipment and storage medium

Abstract

The invention provides a photovoltaic energy storage charging and discharging control method, device and equipment and a storage medium, and relates to the field of photovoltaic energy storage. The method is suitable for a power utilization process in which a photovoltaic energy storage system and an external energy source cooperate to supply power to a load, and comprises the steps of obtaining an output state of the photovoltaic energy storage system and an output state of the external energy source in real time, and determining a first working mode of the photovoltaic energy storage system; obtaining the residual electric quantity of a battery unit in the photovoltaic energy storage system, and determining a second working mode of the battery unit according to a preset first electric quantity threshold value, a preset second electric quantity threshold value and the determined first working mode; when the battery unit is in the charging mode and the electric quantity reaches a second electric quantity threshold value, the battery unit is controlled to be discharged to the target electric quantity and then recharged; and when the battery unit is in the discharge mode and the electric quantity is reduced to a third electric quantity threshold, controlling the battery unit to stop discharging and enter a standby state. Through full-process intelligent regulation and control, energy supply and demand are balanced, the risk of over-charging and over-discharging is avoided, and the economical efficiency and reliability of the system are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic energy storage, in particular to a photovoltaic energy storage charging and discharging control method, device, equipment and storage medium. BACKGROUND

[0002] Solar energy as a clean and renewable energy source has received a lot of attention. Photovoltaic power generation has intermittency and instability, and its output power is greatly affected by factors such as day and night alternation, weather changes, and seasonal changes. At the same time, the output power of photovoltaic power generation often cannot be matched with the load demand in real time. When the photovoltaic power generation is more than the local load demand, the excess power is difficult to store and utilize effectively, which may cause energy waste. When the photovoltaic power generation is insufficient, it needs to rely on external power grid for power supply, which affects the reliability and stability of power supply, which seriously restricts the large-scale application and development of photovoltaic power generation.

[0003] To solve the above problems of photovoltaic power generation, the combination of energy storage technology and photovoltaic power generation has emerged as the times require. The energy storage system can store excess power when the photovoltaic power generation is sufficient, and release power when the photovoltaic power generation is insufficient or the peak demand for electricity, thereby effectively balancing power supply and demand and improving the stability and reliability of the power system. Battery energy storage has been widely used in photovoltaic energy storage due to its high energy density and fast response speed. In the photovoltaic energy storage system, grid-connected and off-grid control technology can realize flexible switching and stable operation of the photovoltaic energy storage system in grid-connected and off-grid modes to meet different power demand and application scenarios. In off-grid mode, the system can independently supply power to the load without being affected by the power grid, which is suitable for remote areas, islands, emergency power supply and other occasions, and improves the autonomy and reliability of power supply. The power grid environment in some parts of Africa is very poor, and the light intensity is very good, so the demand for photovoltaic energy storage equipment is increasing, and the following problems exist: 1) Over-discharge problem. Due to the instability of photovoltaic power generation, the battery cannot store enough power to meet the demand at night, resulting in over-discharge of the battery, which cannot be charged the next day. 2) Overcharge problem. When the light is good, the battery can be fully charged, which may cause overcharge of the battery. Long-term overcharge may cause poor stability and consistency of the battery, and the bucket effect is getting worse, which may cause great hidden danger to the system safety. SUMMARY

[0004] The present application aims to provide a photovoltaic energy storage charging and discharging control method, device, equipment and storage medium, which solves the problems of overcharge and over-discharge of the battery in the existing photovoltaic energy storage system by designing the charging and discharging control strategy of the photovoltaic energy storage system in different working modes.

[0005] To achieve the above purpose, the present application proposes the following technical solutions: In a first aspect, a control method for photovoltaic energy storage charging and discharging is provided, which is suitable for a power consumption process in which a photovoltaic energy storage system and an external energy source cooperate to supply power to a load, and includes the following steps: acquiring an output state of the photovoltaic energy storage system and an output state of the external energy source in real time, and determining a first working mode of the photovoltaic energy storage system; wherein the first working mode includes an off-grid no-light mode, an off-grid light mode, a grid-connected no-light mode, and a grid-connected light mode; acquiring a remaining amount of electricity of a battery unit in the photovoltaic energy storage system, and determining a relationship between the remaining amount of electricity and preset first and second electricity thresholds; determining a second working mode of the battery unit according to the first working mode of the photovoltaic energy storage system and the relationship between the remaining amount of electricity and the preset first and second electricity thresholds; wherein the second working mode includes a charging mode and a discharging mode, and the first electricity threshold is smaller than the second electricity threshold; when the second working mode of the battery unit is the charging mode and the amount of electricity thereof reaches the second electricity threshold, an energy management system controls the battery unit to discharge to a target amount of electricity and then recharge, so as to avoid overcharging of the battery unit; when the second working mode of the battery unit is the discharging mode and the amount of electricity thereof decreases to a third electricity threshold, the energy management system controls the battery unit to stop discharging and enter a standby state, so as to avoid over-discharging of the battery unit; wherein the third electricity threshold is smaller than the first electricity threshold.

[0006] Further, when the photovoltaic energy storage system is in the off-grid no-light mode and under a fault-free condition, then: when the remaining amount of electricity of the battery unit is greater than the first electricity threshold and a battery voltage is greater than a first voltage threshold, the battery unit outputs a voltage for use by the load and enters the discharging mode until the amount of electricity thereof decreases to the third electricity threshold and enters the standby state.

[0007] Further, when the photovoltaic energy storage system is in the off-grid light mode and under a fault-free condition, then: when an output power of a photovoltaic unit of the photovoltaic energy storage system is less than a required power of the load, and the remaining amount of electricity of the battery unit is greater than the first electricity threshold and the battery voltage is greater than the first voltage threshold, the photovoltaic unit and the battery unit of the photovoltaic energy storage system jointly output a voltage for use by the load, and the photovoltaic unit preferentially carries the load, and a remaining power insufficient part is supplied by the battery unit in the discharging mode for use by the load; When the output power of the photovoltaic unit of the photovoltaic energy storage system is greater than the required power of the load, the remaining power of the battery unit is less than the second power threshold, and the battery voltage is less than the second voltage threshold, the photovoltaic unit of the photovoltaic energy storage system outputs voltage for the load, and charges the battery unit at the same time, and the battery unit enters a charging mode; wherein the second voltage threshold is greater than the first voltage threshold.

[0008] Further, when the battery unit enters a discharging mode for the load until the remaining power of the battery unit decreases to a third power threshold, the battery unit enters a standby state, and the photovoltaic energy storage system stops outputting to charge the photovoltaic unit to the battery unit until the remaining power of the battery unit reaches a fourth power threshold, and the photovoltaic energy storage system resumes outputting to load; wherein the fourth power threshold is less than the second power threshold and greater than the first power threshold.

[0009] Further, when the photovoltaic energy storage system is in a grid-connected lightless mode and a fault-free condition, the external energy source preferentially loads the load. When the remaining power of the battery unit is less than the second power threshold and the output power of the external energy source is greater than the required power of the load, the external energy source charges the battery unit while bypassing the load, so that the battery unit enters a charging mode until the remaining power of the battery unit reaches the second power threshold and enters a standby state.

[0010] Further, when the photovoltaic energy storage system is in a grid-connected light mode and a fault-free condition, the external energy source outputs voltage for the load, and when the remaining power of the battery unit is less than the second power threshold and the battery voltage is less than the second voltage threshold, the photovoltaic unit and the external energy source jointly charge the battery unit, so that the battery unit enters a charging mode until the remaining power of the battery unit reaches the second power threshold; wherein the photovoltaic unit preferentially charges.

[0011] In a second aspect, a photovoltaic energy storage charging and discharging control device is provided, comprising: a photovoltaic energy storage system, an external energy source, a load, and an energy management system, the photovoltaic energy storage system comprising a photovoltaic unit, a battery unit, a PCS unit, an MPPT unit, and an STS unit; further comprising: An acquisition and determination module is configured to acquire the output state of the photovoltaic energy storage system and the output state of the external energy source in real time, and determine a first working mode of the photovoltaic energy storage system; wherein the first working mode includes an off-grid lightless mode, an off-grid light mode, a grid-connected lightless mode, and a grid-connected light mode. An acquisition and determination module is configured to acquire the output state of the photovoltaic energy storage system and the output state of the external energy source in real time, and determine a first working mode of the photovoltaic energy storage system; wherein the first working mode includes an off-grid lightless mode, an off-grid light mode, a grid-connected lightless mode, and a grid-connected light mode. determining module, configured to determine a second working mode of the battery unit according to a relationship between the first working module of the photovoltaic energy storage system, the residual electric quantity and preset first and second electric quantity thresholds; wherein the second working mode comprises a charging mode and a discharging mode, and the first electric quantity threshold is less than the second electric quantity threshold; Further, the energy management system controls the battery unit to discharge to a target electric quantity and then recharge when the second working mode of the battery unit is the charging mode and the electric quantity of the battery unit reaches the second electric quantity threshold, so as to avoid overcharging of the battery unit; the energy management system controls the battery unit to stop discharging and enter a standby state when the second working mode of the battery unit is the discharging mode and the electric quantity of the battery unit decreases to a third electric quantity threshold, so as to avoid overdischarging of the battery unit; wherein the third electric quantity threshold is less than the first electric quantity threshold.

[0012] Further, when the photovoltaic energy storage system is in the off-grid light mode and has no fault, the battery unit enters the discharging mode to supply the load until the residual electric quantity of the battery unit decreases to the third electric quantity threshold, the energy management system controls the battery unit to enter the standby state, controls the photovoltaic energy storage system to stop outputting, controls the photovoltaic unit to charge the battery unit until the residual electric quantity of the battery unit reaches a fourth electric quantity threshold, and then controls the photovoltaic energy storage system to resume outputting to carry the load; wherein the fourth electric quantity threshold is less than the second electric quantity threshold and greater than the first electric quantity threshold.

[0013] In a third aspect, an electronic device is provided, comprising at least one processor coupled with a memory, and the memory stores a computer program configured to be executed by the processor to implement the above-mentioned photovoltaic energy storage charging and discharging control method.

[0014] In a fourth aspect, a computer readable storage medium is provided, and the computer readable storage medium stores a computer program configured to be executed by a computer to implement the above-mentioned photovoltaic energy storage charging and discharging control method.

[0015] According to the above technical solutions, the technical solutions of the present application have the following beneficial effects: The photovoltaic energy storage charging and discharging control method, device, equipment and storage medium disclosed by the application are suitable for the power consumption process of the photovoltaic energy storage system and external energy cooperating to supply power to a load, and include the following steps: acquiring the output state of the photovoltaic energy storage system and the output state of the external energy in real time, and determining the first working mode of the photovoltaic energy storage system; acquiring the residual power of the battery unit in the photovoltaic energy storage system, and determining the second working mode of the battery unit according to the preset first power threshold and second power threshold and the first working mode of the photovoltaic energy storage system; when the battery unit is in the charging mode and the power thereof reaches the second power threshold, controlling the battery unit to discharge to the target power and then recharge, so as to avoid overcharging; and when the battery unit is in the discharging mode and the power thereof decreases to the third power threshold, controlling the battery unit to stop discharging and enter the standby state, so as to avoid overdischarging. The application balances the supply and demand of energy through intelligent regulation and control in the whole process, avoids the risks of overcharging and overdischarging, and significantly improves the economy and reliability of the system.

[0016] The control strategy of the application considers different working modes of the photovoltaic energy storage system, determines the charging mode or discharging mode of the battery unit according to the output state of the photovoltaic unit and the external energy, avoids the risks of overcharging and overdischarging, avoids damage to the battery unit, and prolongs the service life of the battery unit; the control method of the application preferentially utilizes the photovoltaic unit for the battery unit in the charging mode, and the external energy is used to supplement the power; the control method of the application preferentially guarantees the load demand for the battery unit in the discharging mode; and the application fully ensures the efficient and safe charging and discharging process of the battery unit of the photovoltaic energy storage system.

[0017] It should be understood that all combinations of the aforementioned concepts and additional concepts described in greater detail below can be seen as part of the subject matter of the present disclosure as long as such concepts are not mutually inconsistent.

[0018] The foregoing and other aspects, embodiments and features of the present teachings can be better understood from the following description of the present teachings taken in conjunction with the accompanying drawings. Other aspects, embodiments and features of the present teachings will be apparent from the description that follows and from the claims. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings are not drawn to true scale. In the drawings, each same or like component is denoted with the same reference numeral irrespective of its number of appearance. For the sake of clarity, not every component of each drawing is labeled in each figure. Now, embodiments of various aspects of the present teachings will be described with reference to the drawings, wherein: Figure 1 A schematic diagram of an off-grid lightless mode of a photovoltaic energy storage system is provided for the present application; Figure 2A schematic diagram of an off-grid light mode of a photovoltaic energy storage system provided in the present application; Figure 3 A schematic diagram of a grid-connected lightless mode of a photovoltaic energy storage system provided in the present application; Figure 4 A schematic diagram of a grid-connected light mode of a photovoltaic energy storage system provided in the present application; Figure 5 A schematic diagram of a control device for photovoltaic energy storage charging and discharging provided in the present application; Figure 6 A schematic diagram of a control structure of a photovoltaic energy storage system provided in the present application; Figure 7 An example diagram of an electronic device provided in the present application. DETAILED DESCRIPTION

[0020] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are some, but not all of the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should have the usual meanings understood by those of ordinary skill in the art to which the present application belongs.

[0021] The terms "first", "second", and similar terms used in the patent application specification and claims of the present application do not represent any order, number or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms "a", "an" or "the" and the like do not represent a quantity limitation, but represent the existence of at least one. The terms "include" or "contain" and the like mean that the elements or objects appearing before "include" or "contain" cover the features, integers, steps, operations, elements and / or components listed after "include" or "contain", and do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, components and / or sets thereof.

[0022] Based on the current poor grid environment, photovoltaic energy storage equipment is added to ensure power demand, but the photovoltaic energy storage equipment is unstable, and there are problems of insufficient power storage and battery over-discharge at night, and there are problems of battery overcharge when the sunlight is good; The overcharge and overdischarge of the battery will cause damage to the battery, which will cause safety hazards to the equipment; The present application aims to provide a photovoltaic energy storage charging and discharging control method, device, equipment and storage medium, which determines the working mode of the battery unit according to the different working modes of the photovoltaic energy storage system, sets accurate control scheme for different working modes of the battery unit, avoids overcharge and overdischarge of the battery unit, and improves the power safety of the photovoltaic energy storage system.

[0023] Next, in combination with the drawings and specific embodiments, the photovoltaic energy storage charging and discharging control method, device, equipment and storage medium disclosed by the present application will be further described in detail.

[0024] The photovoltaic energy storage charging and discharging control method disclosed by the present application is suitable for the power consumption process of the photovoltaic energy storage system and external energy cooperating to supply power to the load, which comprises: Real-time acquisition of the output state of the photovoltaic energy storage system and the output state of the external energy, to determine the first working mode of the photovoltaic energy storage system; wherein the first working mode includes off-grid no light mode, off-grid light mode, grid-connected no light mode and grid-connected light mode; Acquire the remaining power of the battery unit in the photovoltaic energy storage system, and judge the relationship between the remaining power and the first and second preset power thresholds; According to the first working mode of the photovoltaic energy storage system, the relationship between the remaining power and the first and second preset power thresholds, the second working mode of the battery unit is determined; wherein the second working mode includes charging mode and discharging mode, and the first power threshold is less than the second power threshold; When the second working mode of the battery unit is charging mode and its power reaches the second power threshold, the energy management system controls the battery unit to discharge to the target power and then recharge to avoid overcharging of the battery unit; when the second working mode of the battery unit is discharging mode and its power decreases to the third power threshold, the energy management system controls the battery unit to stop discharging and enter standby state to avoid overdischarge of the battery unit; wherein the third power threshold is less than the first power threshold.

[0025] The protection scheme for overcharge and overdischarge of the battery unit in each first working mode of the photovoltaic energy storage system is described as follows. In the embodiment, the first, second, third and fourth power thresholds are set to 1%, 100%, 0 and 5% respectively, and the first and second voltage thresholds are set to 3.05V and 3.5V respectively; the external energy is grid (GRID) or generator (GEN).

[0026] Figure 1The photovoltaic energy storage system is in off-grid light mode and no fault condition, at this time the photovoltaic unit of the photovoltaic energy storage system cannot start, and the external energy is not connected; when the remaining power of the battery unit is greater than 1% and the battery voltage is greater than 3.05V, the battery unit outputs voltage for the load, enters the discharge mode until the power is reduced to 0 to enter the standby state; when the remaining power of the battery unit is 0 and the battery voltage is less than 3.05V, the photovoltaic energy storage system stops discharging, and the battery unit enters the standby state and does not output power to the outside except for part of the internal self-consumption power, and stops the load. In addition, when the load (LOAD) is not connected, the photovoltaic energy storage system is in standby.

[0027] Figure 2 The photovoltaic energy storage system is in off-grid light mode and no fault condition, at this time the photovoltaic unit of the photovoltaic energy storage system cannot start, and the external energy is not connected; when the remaining power of the battery unit is greater than 1% and the battery voltage is greater than 3.05V, the battery unit outputs voltage for the load, enters the discharge mode until the power is reduced to 0 to enter the standby state; when the remaining power of the battery unit is 0 and the battery voltage is less than 3.05V, the photovoltaic energy storage system stops discharging, and the battery unit enters the standby state and does not output power to the outside except for part of the internal self-consumption power, and stops the load. In addition, when the load (LOAD) is not connected, the photovoltaic energy storage system is in standby. When the output power of the photovoltaic unit of the photovoltaic energy storage system is less than the required power of the load, and the remaining power of the battery unit is greater than 1% and the battery voltage is greater than 3.05V, the photovoltaic unit and the battery unit of the photovoltaic energy storage system jointly output voltage for the load, and the photovoltaic unit preferentially carries the load, and the remaining power is insufficient part is supplied to the load by the battery unit entering the discharge mode; in order to avoid excessive discharge of the battery unit, after the battery unit enters the discharge mode to supply the load until the remaining power is reduced to 0 to enter the standby state, the photovoltaic energy storage system stops outputting to charge the battery unit by the photovoltaic unit until the remaining power of the battery unit reaches 5%, and the photovoltaic energy storage system resumes outputting to carry the load, and the process of carrying the load and discharging, stopping outputting and charging is repeated.

[0028] When the output power of the photovoltaic unit of the photovoltaic energy storage system is greater than the required power of the load, and the remaining power of the battery unit is less than 100% and the battery voltage is less than 3.5V, the photovoltaic unit of the photovoltaic energy storage system outputs voltage for the load while charging the battery unit, and the battery unit enters the charging mode; after the battery unit is fully charged in the charging mode, the energy management system controls the battery unit to actively discharge, such as low-power discharge of 2KW to a target power, such as 95%; then the photovoltaic unit recharges the battery unit until it is fully charged.

[0029] In addition, when the load is not connected, it is first judged whether the remaining power of the battery unit reaches 100%, if the battery unit is fully charged, the photovoltaic energy storage system enters the standby state; if the remaining power is less than 100%, the photovoltaic unit directly charges the battery unit, and the system enters the standby state when the power is charged to 100%.

[0030] Figure 3The photovoltaic energy storage system is in grid-connected lightless and fault-free condition, the photovoltaic unit of the photovoltaic energy storage system cannot be started, the external energy is connected, and the external energy is preferentially used to carry the load; When the remaining power of the battery unit is less than 100% and the output power of the external energy is greater than the required power of the load, the external energy charges the battery unit while bypassing the load, so that the battery unit enters a charging mode until the remaining power of the battery unit reaches 100%, and the external energy continues to bypass the load.

[0031] In addition, when the load is not connected, it is first determined whether the remaining power of the battery unit reaches 100%. If the battery unit is fully charged, the battery unit enters a standby state. If the remaining power is less than 100%, the external energy directly charges the battery unit, and the system enters a standby state when the battery unit is fully charged.

[0032] Figure 4 The photovoltaic energy storage system is in grid-connected lightless and fault-free condition, the photovoltaic unit of the photovoltaic energy storage system cannot be started, the external energy is connected, and the external energy is preferentially used to carry the load; When the remaining power of the battery unit is less than 100% and the output power of the external energy is greater than the required power of the load, the external energy charges the battery unit while bypassing the load, so that the battery unit enters a charging mode until the remaining power of the battery unit reaches 100%, and the external energy continues to bypass the load.

[0033] In addition, when the load is not connected, it is first determined whether the remaining power of the battery unit reaches 100%. If the battery unit is fully charged, the battery unit enters a standby state. If the remaining power is less than 100%, the external energy directly charges the battery unit, and the system enters a standby state when the battery unit is fully charged.

[0034] In summary, under the condition that the external energy is connected or the photovoltaic unit is started, if the battery unit is allowed to be charged, the energy management system usually controls the battery unit to enter a charging mode, if the battery unit is fully charged, the energy management system controls the battery unit to enter a standby state; if the external energy is not connected and the photovoltaic unit is not started, the energy management system usually controls the battery unit to enter a discharging mode; if the photovoltaic energy storage system has a fault, the energy management system usually controls the photovoltaic energy storage system to enter a fault mode.

[0035] The application is to realize efficient utilization of photovoltaic energy, safe and stable operation of photovoltaic energy storage system and collaborative matching. According to different working modes of the photovoltaic energy storage system, the battery unit is determined to be in charging mode or discharging mode according to the output state of the photovoltaic unit and the external energy source, so as to avoid overcharging or overdischarging risk and avoid damage to the battery unit and prolong the service life of the battery unit. The control method of the application gives priority to using the photovoltaic unit for the battery unit in the charging mode, and the external energy source is used to supplement the shortage. Through intelligent regulation and control of the whole process, the energy supply and demand are balanced, the risk of overcharging and overdischarging is avoided, and the economy and reliability of the system are significantly improved.

[0036] Based on the same inventive concept as the above method embodiment, the application embodiment also discloses a control device for photovoltaic energy storage charging and discharging, as shown in Figure 5 The application discloses a control device for photovoltaic energy storage charging and discharging, as shown in Further, the energy management system controls the battery unit to discharge to a target electric quantity and then recharge when the second working mode of the battery unit is the charging mode and the electric quantity reaches the second electric quantity threshold, so as to avoid overcharging of the battery unit; the energy management system controls the battery unit to stop discharging and enter a standby state when the second working mode of the battery unit is the discharging mode and the electric quantity decreases to a third electric quantity threshold, so as to avoid overdischarging of the battery unit; wherein the third electric quantity threshold is less than the first electric quantity threshold.

[0037] The device is used to realize the steps of the control method for photovoltaic energy storage charging and discharging disclosed in the above embodiments, which has been described.

[0038] The PCS unit is an energy storage converter, which is the core equipment responsible for power conversion and control in the photovoltaic energy storage system. Its main function is to realize AC-DC power conversion between the energy storage battery and external energy or load, coordinate the charging and discharging process of the energy storage system, and ensure safe and efficient operation of the system. The MTTP unit is a maximum power point tracking device, which is one of the core components of the photovoltaic power generation system. Its core function is to track the maximum power output point of the solar panel in real time, ensuring that the photovoltaic system always converts solar energy with the highest efficiency, thereby improving overall power generation income. The STS unit is a static transfer switch, which is a power electronic device used to realize fast and uninterrupted switching between two power sources, such as the main power source and the backup power source. Its core role is to ensure continuous power supply to critical loads and avoid losses caused by power interruptions.

[0039] The energy management system, EMS, is an intelligent system that realizes the optimization management of the whole process of energy production, storage, distribution and consumption through data acquisition, analysis, decision and control. Its core goal is to improve energy utilization efficiency, reduce energy consumption cost, ensure stable operation of the energy system, and support efficient integration of renewable energy. EMS is usually composed of hardware such as servers, controllers, communication devices, and software such as data acquisition modules, analysis algorithms, control logic, and human-computer interaction interfaces. The core is optimization algorithms such as dynamic programming and model predictive control, which realize intelligent decision of energy scheduling through algorithms. In this embodiment, the functions of the acquisition determination module, the acquisition judgment module and the determination module are integrated in the energy management system, and the energy management system uniformly realizes data acquisition, data judgment, target determination and instruction issuance.

[0040] The battery unit includes a battery management system BMS, which is a core electronic system specially used for monitoring, protecting, controlling and optimizing the operating state of the battery pack. Through real-time acquisition of battery parameters, execution of safety protection strategies, and balancing of battery performance, it ensures efficient, safe and long-life operation of the battery pack, and is an indispensable key component in various electrochemical energy storage systems. The battery parameters include the temperature and voltage of the battery. The battery management system BMS makes real-time processing and judgment on the battery unit being in a high-voltage state, standby state, charging mode or discharging mode, adjusts the working state of the battery unit in real time, dynamically adjusts the charging current and voltage, and ensures efficient and safe charging process.

[0041] Due to the uncertainty of photovoltaic, the instability of the power grid, and the uncertainty of the load, in order to ensure that the entire system can operate safely, efficiently, stably and persistently, the MPPT unit, PCS unit, STS unit, EMS and battery management system BMS need to work together effectively.

[0042] In combination with Figure 6The control diagram of the photovoltaic energy storage system shown shows that the EMS uses RS485 communication to interact with the MPPT unit, PCS unit, and the electricity meters EM set at the external energy and load ends. The EMS uses CAN communication to interact with the battery management system BMS.

[0043] In practical implementation, the photovoltaic energy storage system provided by this invention is controlled through an industrial tablet PC. The industrial tablet PC can be designed as a high-performance embedded industrial tablet PC based on the Linux+QT5.14.2 system, featuring a powerful quad-core Cortex-A55 processor with a frequency of up to 2.0GHz, 2GB DDR4 SDRAM, a 10.1-inch TFT true-color LCD screen with a multi-touch capacitive touchscreen, 2GB DDR4 SDRAM memory, a 16GB hard drive, two USB 2.0 HOST interfaces, one USB OTG interface, three RJ45 Gigabit Ethernet interfaces, one SD card / TF card interface, 12 digital inputs, 12 digital outputs, five RS-485 communication interfaces, and three CAN communication interfaces.

[0044] Existing photovoltaic energy storage systems vary across different regional environments and require adaptive commissioning to suit local grid and photovoltaic conditions.

[0045] exist Figure 1 In the off-grid, no-light mode shown, the MPPT unit cannot start, there is no external power, and the STS unit automatically switches to off-grid mode; the EMS sends a command to the PCS unit to start, the PCS unit enters V / F mode to operate off-grid, and outputs voltage to supply the load; when the battery unit stops discharging, the EMS sends a command to the PCS unit to stop the PCS unit and enter standby mode.

[0046] Figure 2 In the off-grid solar mode shown, when the photovoltaic unit starts up, the EMS sends a command to the MPPT unit to start up. Without external energy, the STS unit automatically switches to off-grid mode. When the battery unit's charge is 0%, the EMS sends a command to the PCS unit to stop the PCS unit and enter standby mode. Before the remaining charge of the battery unit reaches 5%, the PCS unit remains in standby mode, without output or load. After the remaining charge of the battery unit reaches 5%, the EMS sends a command to the PCS unit to start up and begin outputting load.

[0047] Figure 3In the grid-connected no-light mode shown, there is no photovoltaic unit, the MPPT cannot be started, there is an external energy source and the voltage is normal, there is no overvoltage, undervoltage, wrong phase, and phase shortage problem, and the STS unit automatically cuts into the grid-connected state; when charging the battery unit, the EMS issues an instruction to the PCS unit to charge, and if the remaining power of the battery unit reaches 100%, the EMS issues an instruction to the PCS unit to be in standby state.

[0048] Figure 4 In the grid-connected light mode shown, both the photovoltaic unit and the external energy source exist, the EMS issues an instruction to the MPPT unit to start, there is an external energy source and the voltage is normal, there is no overvoltage, undervoltage, wrong phase, and phase shortage problem, and the STS unit automatically cuts into the grid-connected state; when charging the battery unit, the EMS issues an instruction to the PCS unit to charge, and if the remaining power of the battery unit reaches 100%, the EMS issues an instruction to the PCS unit to be in standby state.

[0049] In summary, the EMS comprehensively judges the state of the system according to the load condition of the photovoltaic energy storage system (provided by the load meter) and the external energy source condition (grid or generator state), so as to control the power of the MPPT unit or the PCS unit, and the EMS intelligently schedules each unit; Specifically, it includes: according to the output power of the photovoltaic unit, the state of the battery unit and the load demand, intelligent scheduling is realized; load priority principle, when the output power of the photovoltaic unit is greater than the load demand, the excess part is used to charge the battery unit; when the external energy source exists, the external energy source is loaded, and the external energy source and the photovoltaic unit charge the battery unit at the same time; when the output power of the photovoltaic unit is less than the load demand, the battery unit and the photovoltaic unit jointly load. In addition, when regulating the power of the MPPT unit, the EMS and the MPPT unit communicate, the power required by the MPPT unit to output, the actual output power of the photovoltaic unit are judged by the model algorithm, and an instruction is issued to the MPPT unit to adjust the working parameters of the MPPT, so as to realize the charging and loading operation of the battery unit and meet the demand in different stages; when regulating the power of the PCS unit, the EMS and the PCS unit communicate, whether the PCS unit is in rectification state or inversion state, and the rectification power and the inversion power are judged by the model algorithm, and an instruction is issued to the PCS unit to adjust the PCS unit to be in discharge mode, charging mode, small power discharge state or standby state.

[0050] For the off-grid no-light mode, off-grid light mode, grid-connected no-light mode or grid-connected light mode of the photovoltaic energy storage system, the photovoltaic energy storage charging and discharging control device proposed in this embodiment adopts the same control strategy as the corresponding control method, which will not be described here.

[0051] Based on the same inventive concept as the method embodiments, the electronic device in the embodiments of the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the electronic device implements the control method of photovoltaic energy storage charging and discharging in the above embodiments.

[0052] In an embodiment, the electronic device can be a server, and in this embodiment, the structure of the electronic device can be as shown in the figure. Figure 7 The electronic device includes a memory 201, a communication module 203, and one or more processors 202.

[0053] The memory 201 is used to store the computer program executed by the processor 202. The memory 201 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system and programs required for running instant messaging functions, etc.; the data storage area can store various instant messaging information and operation instruction sets, etc. The memory 201 can be a volatile memory such as a random-access memory (RAM); the memory 201 can also be a non-volatile memory such as a read-only memory, a flash memory, a hard disk drive (HDD) or a solid-state drive (SSD); or the memory 201 can be any other medium capable of carrying or storing a desired computer program in the form of instructions or data structures and capable of being accessed by a computer, but is not limited thereto. The memory 201 can be a combination of the above memories.

[0054] The processor 202 can include one or more central processing units (CPUs) or digital processing units, etc. The processor 202 is used to call the computer program stored in the memory 201 to implement the above-mentioned audio data processing method.

[0055] The communication module 203 is used to communicate with terminal devices and other servers.

[0056] The specific connection medium between the above-mentioned memory 201, communication module 203 and processor 202 is not limited in the embodiments of the present application. In the embodiments of the present application, the memory 201 and the processor 202 are connected through a bus 204, and the bus 204 is connected through a bus interface 205. Figure 7 Figure 7 ​The connections between the various components are described using arrows, and the connections between other components are only illustrative and are not limited. The bus 204 can be divided into an address bus, a data bus, a control bus, etc. For ease of description, Figure 7 Only one arrow is described in the figure, but there is not only one bus or one type of bus.

[0057] With the same inventive concept as the above method embodiments, the embodiments of the present application also provide a computer readable storage medium for storing a computer program, which, when running on a computer, causes the electronic device to implement the above-mentioned photovoltaic energy storage charging and discharging control method. The computer readable storage medium can be a readable signal medium or a readable storage medium. The readable storage medium may, for example, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or component, or any combination of the above. More specific examples (non-exhaustive list) of readable storage medium include: electrical connection with one or more conductive wires, portable disk, magnetic disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the above.

[0058] With the same inventive concept as the above method embodiments, the embodiments of the present application also provide a computer program product, which includes a computer program, when the program product runs on an electronic device, the computer program is used to make the electronic device execute the steps in the photovoltaic energy storage charging and discharging control method according to various exemplary embodiments of the present application described in the specification. The program product can adopt any combination of one or more readable media. These computer program commands can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the commands executed by the processor of the computer or other programmable data processing device produce a method for implementing the functions specified in one or more flows or blocks. Figure 1 The flow or block Figure 1 The device that implements the functions specified in one or more flows or blocks.

[0059] Although the present application has been disclosed with reference to the preferred embodiments above, it is not intended to limit the present application. Those skilled in the art, without departing from the spirit and scope of the present application, can make various modifications and improvements. Therefore, the scope of protection of the present application shall be subject to the scope defined by the claims.

Claims

1. A method for controlling the charging and discharging of photovoltaic energy storage, characterized in that, This applies to power supply processes where photovoltaic energy storage systems and external energy sources work together to supply power to loads, including: The output status of the photovoltaic energy storage system and the output status of the external energy are acquired in real time to determine the first working mode of the photovoltaic energy storage system; wherein, the first working mode includes off-grid no-light mode, off-grid with-light mode, grid-connected no-light mode, and grid-connected with-light mode; Obtain the remaining power of the battery cells in the photovoltaic energy storage system, and determine the relationship between the remaining power and a preset first power threshold and a second power threshold; Based on the first working module of the photovoltaic energy storage system and the relationship between the remaining power and the preset first power threshold and second power threshold, the second working mode of the battery cell is determined; wherein, the second working mode includes a charging mode and a discharging mode, and the first power threshold is less than the second power threshold; When the second operating mode of the battery cell is charging mode and its charge reaches the second charge threshold, the energy management system controls the battery cell to discharge to the target charge and then recharge it to avoid overcharging the battery cell. When the second operating mode of the battery cell is the discharge mode and its power level drops to the third power threshold, the energy management system controls the battery cell to stop discharging and enter the standby state to avoid over-discharging of the battery cell; wherein the third power threshold is less than the first power threshold.

2. The photovoltaic energy storage charging and discharging control method according to claim 1, characterized in that, If the photovoltaic energy storage system is in an off-grid, non-light-generating mode and under fault-free conditions, then: When the remaining charge of the battery cell is greater than the first charge threshold and the battery voltage is greater than the first voltage threshold, the battery cell outputs voltage to supply the load and enters a discharge mode until its charge is reduced to the third charge threshold and it enters a standby state.

3. The photovoltaic energy storage charging and discharging control method according to claim 1, characterized in that, If the photovoltaic energy storage system is in off-grid, solar-powered mode and without faults, then: When the output power of the photovoltaic unit of the photovoltaic energy storage system is less than the power required by the load, and the remaining power of the battery unit is greater than the first power threshold and the battery voltage is greater than the first voltage threshold, the photovoltaic unit and the battery unit of the photovoltaic energy storage system jointly output voltage to supply the load, and the photovoltaic unit takes priority to carry the load, and the remaining power is insufficient and the battery unit enters the discharge mode to supply the load. When the output power of the photovoltaic unit of the photovoltaic energy storage system is greater than the power required by the load, the remaining power of the battery unit is less than the second power threshold and the battery voltage is less than the second voltage threshold, the photovoltaic unit of the photovoltaic energy storage system outputs voltage to supply the load while charging the battery unit, and the battery unit enters the charging mode; wherein, the second voltage threshold is greater than the first voltage threshold.

4. The photovoltaic energy storage charging and discharging control method according to claim 3, characterized in that, When the battery cell enters discharge mode to supply the load until its remaining charge decreases to the third charge threshold, the battery cell enters standby mode, and the photovoltaic energy storage system stops outputting to allow the photovoltaic cell to charge the battery cell until the remaining charge of the battery cell reaches the fourth charge threshold, at which point the photovoltaic energy storage system resumes output to supply the load; wherein the fourth charge threshold is less than the second charge threshold and greater than the first charge threshold.

5. The photovoltaic energy storage charging and discharging control method according to claim 1, characterized in that, When the photovoltaic energy storage system is connected to the grid without light and without faults, the external energy source will take priority in power supply. When the remaining charge of the battery cell is less than the second charge threshold and the output power of the external energy source is greater than the power required by the load, the external energy source charges the battery cell by bypassing the load, so that the battery cell enters the charging mode until the remaining charge of the battery cell reaches the second charge threshold and then enters the standby state.

6. The photovoltaic energy storage charging and discharging control method according to claim 1, characterized in that, When the photovoltaic energy storage system is in grid-connected, solar-powered mode and without faults, the external energy source outputs voltage to power the load. When the remaining charge of the battery cell is lower than a second charge threshold and the battery voltage is lower than a second voltage threshold, the photovoltaic cell and the external energy source jointly charge the battery cell to put it into charging mode until the remaining charge of the battery cell reaches the second charge threshold. The photovoltaic cell is charged first.

7. A control device for charging and discharging photovoltaic energy storage, characterized in that, The system includes a photovoltaic energy storage system, an external energy source, a load, and an energy management system. The photovoltaic energy storage system comprises photovoltaic units, battery units, PCS units, MPPT units, and STS units; it also includes: The acquisition and determination module is used to acquire the output status of the photovoltaic energy storage system and the output status of the external energy in real time, and determine the first working mode of the photovoltaic energy storage system; wherein, the first working mode includes off-grid no-light mode, off-grid with-light mode, grid-connected no-light mode, and grid-connected with-light mode; The acquisition and judgment module is used to acquire the remaining power of the battery unit in the photovoltaic energy storage system and determine the relationship between the remaining power and the preset first power threshold and second power threshold. The determining module is used to determine the second operating mode of the battery cell based on the first operating module of the photovoltaic energy storage system, the relationship between the remaining power and the preset first power threshold and second power threshold; wherein the second operating mode includes a charging mode and a discharging mode, and the first power threshold is less than the second power threshold; Furthermore, when the second operating mode of the battery cell is charging mode and its charge reaches a second charge threshold, the energy management system controls the battery cell to discharge to the target charge and then recharge, so as to avoid overcharging the battery cell; when the second operating mode of the battery cell is discharging mode and its charge drops to a third charge threshold, the energy management system controls the battery cell to stop discharging and enter a standby state, so as to avoid over-discharging the battery cell; wherein, the third charge threshold is less than the first charge threshold.

8. The photovoltaic energy storage charging and discharging control device according to claim 7, characterized in that, When the photovoltaic energy storage system is in off-grid, solar-powered mode and without faults, and the battery unit enters discharge mode to supply power to the load until its remaining power decreases to the third power threshold, the energy management system controls the battery unit to enter standby mode and controls the photovoltaic energy storage system to stop outputting power. The photovoltaic unit charges the battery unit until the remaining power of the battery unit reaches the fourth power threshold, and then controls the photovoltaic energy storage system to resume output to power the load. The fourth power threshold is less than the second power threshold and greater than the first power threshold.

9. An electronic device, characterized in that, It includes at least one processor coupled to a memory containing a computer program configured to be executed by the processor to perform the photovoltaic energy storage charging and discharging control method according to any one of claims 1-6.

10. A computer-readable storage medium, characterized in that, It stores a computer program, which, when executed by a computer, implements the photovoltaic energy storage charging and discharging control method according to any one of claims 1-6.

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