Multi-machine parallel energy storage system and its charge / discharge control method

Abstract

This application relates to the technical field of energy storage power supplies, and more particularly, to a multi-machine parallel energy storage system and a charge / discharge control method thereof. The multi-machine parallel energy storage system includes a single-channel renewable energy device, at least two energy storage devices, an AC bus, and a load. When the renewable energy device is connected to one of the at least two energy storage devices, a master and a slave are identified, and the master dynamically acquires first data, second data, and third data. The master determines the current state of the multi-machine parallel energy storage system based on the first data, second data, and third data. If the current state meets a charging condition, the renewable energy device is controlled to supply electrical energy to the master. If the master is fully charged, the renewable energy device is controlled to supply electrical energy to the slave. When multiple energy storage devices are connected in parallel, the application can automatically charge the multiple energy storage devices by simply connecting one set of single-channel renewable energy devices.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to a Chinese patent application filed with the China Patent Office on February 14, 2023, bearing application number 202310108608.5 and entitled "Multi-machine parallel energy storage system and its charge / discharge control method," the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of energy storage power supply, and particularly to a multi-machine parallel energy storage system and its charge / discharge control method. [Background technology]

[0003] With the development of the photovoltaic (PV) industry and the boom in outdoor travel, the photovoltaic energy storage industry is also developing rapidly, and the application scenarios of photovoltaic energy storage products are becoming more and more diverse. Faced with the ever-increasing demand for load power, it is common for multiple energy storage devices to be connected in parallel to output power to supply electricity to high-power loads.

[0004] Here, the AC sides of each independent energy storage device are connected to each other, and the AC sides can only be used to drive a load. Because the battery side and DC charging side of each independent energy storage device are independent, each energy storage device must be connected to a separate photovoltaic (solar energy) solar panel to charge the energy storage device with solar energy. However, since users often only have one solar energy photovoltaic panel, they must manually connect each photovoltaic solar panel to each energy storage device one by one to charge them. This is not only cumbersome, but also poses safety issues when repeatedly connecting photovoltaic solar panels to each energy storage device. Summary of the Invention [Problem to be solved by the invention]

[0005] The present application provides a multi-machine parallel energy storage system and a charge / discharge control method thereof, which solves the problem that when multiple energy storage devices are connected in parallel, users need to connect renewable energy devices to each energy storage device one by one for charging, which is cumbersome and poses safety risks. [Means for solving the problem]

[0006] In order to solve the above technical problems, one technical solution adopted in the embodiments of the present application is as follows: a single-channel renewable energy device, at least two energy storage devices, an AC bus, and a load, wherein the renewable energy device is for connecting to one of the at least two energy storage devices, and AC output terminals of the at least two energy storage devices are connected to the load via the AC bus; When the renewable energy device is connected to any one of the at least two energy storage devices, the energy storage device connected to the renewable energy device is identified as a master, and the energy storage device not connected to the renewable energy device is identified as a slave, and the master: dynamically acquiring first data of the master, second data of the slave, and third data of the renewable energy device; determining a current state of the multi-machine parallel energy storage system based on the first data, the second data, and the third data; Provided is a multi-machine parallel energy storage system, which is used to control the renewable energy devices to supply electrical energy to the master when the current state satisfies a charging condition, and to control the renewable energy devices to supply electrical energy to the slaves when the master is fully charged.

[0007] Preferably, determining the current state of the multi-machine parallel energy storage system based on the first data, the second data, and the third data includes: calculating a total power of a load of the multi-machine parallel energy storage system based on the first data and the second data; determining whether the third data, including the power generation power of the renewable energy devices, is greater than the total power of the load; determining that the current state satisfies the charging condition if the third data is greater than the total power of the load; and determining that the current state does not satisfy the charging condition if the third data is equal to or less than the total power of the load.

[0008] More preferably, the system further includes, after determining that the current state does not satisfy the charging condition, controlling the renewable energy device to supply electrical energy to the load, and simultaneously discharging the master and the slave in parallel to supply power to the load.

[0009] Preferably, the system adopts a dual-loop control method: an AC output voltage outer loop and an inverter current inner loop.

[0010] More preferably, the master introduces photovoltaic power generation power and battery discharge power as feedforward control into the AC output voltage outer loop of the dual-loop control system, and the AC output target voltage of the master is expressed by the following equation: JPEG2026500128000002.jpg1068JPEG2026500128000003.jpg1037 Here, VAC Ref_M1 is the master AC output voltage target value, and VAC rated is the rated AC output voltage of the system, and P PV is the power generated by the current renewable energy device, and P ratedis the system rated power, ΔU is the AC output voltage adjustment amount, which is correlated with the discharge power of the master battery pack, and P discharge is the discharge power of the master battery pack, Ki is the coefficient of the output voltage adjustment rate corresponding to the discharge power of the master battery pack, which is adjusted based on the demand for the dynamic response of the actual load, 0 < Ki ≤ 1. The larger Ki is, the faster the response at the moment of rapid load change, and the shorter the time taken for the output voltage adjustment. The smaller Ki is, the longer the time taken for the output voltage adjustment, and the smoother the adjustment process becomes.

[0011] More preferably, the slave adopts a constant voltage control method in the AC output voltage outer loop of the dual-loop control method, and the AC output target voltage of the slave is represented by the following formula, JPEG2026500128000004.jpg536 Here, VAC Ref_M2 is the AC output voltage target value of the slave, and VAC rated is the system AC rated output voltage.

[0012] More preferably, when there are at least three energy storage devices, the slave includes at least two of the energy storage devices, and the master is further used to specify the charging order of the slave according to a predetermined rule when the master is fully charged, and control the renewable energy device based on the charging order to supply electrical energy from the master to the slave.

[0013] In order to solve the above technical problems, another technical solution adopted in the embodiments of the present application is as follows: A charge / discharge control method for a multi-machine parallel energy storage system, which is applied to the multi-machine parallel energy storage system, wherein the multi-machine parallel energy storage system includes a renewable energy device, at least two energy storage devices, an AC bus, and a load, the renewable energy device is connected to the energy storage device, and AC output terminals of the at least two energy storage devices are connected to the load via the AC bus, and when the renewable energy device is connected to any one of the at least two energy storage devices, the energy storage device connected to the renewable energy device is called a master. and identifying the energy storage device not connected to the renewable energy device as a slave, and identifying the energy storage device as a slave, wherein the charge and discharge control method for the system includes: dynamically acquiring first data of the master, second data of the slave, and third data of the renewable energy device; determining a current state of the multi-machine parallel energy storage system based on the first data, the second data, and the third data; when the current state satisfies a charging condition, controlling the renewable energy device to supply electric energy to the master; and when the master is fully charged, controlling the renewable energy device to supply electric energy to the slave.

[0014] Preferably, the charge / discharge control method of the system includes that the system adopts a dual-loop control method of an output voltage outer loop and an inverter current inner loop, and the master introduces photovoltaic power generation power and battery discharge power as feedforward control into the AC output voltage outer loop of the dual-loop control method, and the AC output target voltage of the master is expressed by the following equation: JPEG2026500128000005.jpg1068JPEG2026500128000006.jpg1037 Here, VAC Ref_M1 is the master's AC output voltage target value, and VAC rated is the system AC rated output voltage, and P PV is the power generation power of the current renewable energy device, and P rated is the system rated power, ΔU is the output voltage adjustment amount, which is correlated with the discharge power of the battery pack, and P discharge is the discharge power of the master's battery pack; Ki is the coefficient of the output voltage adjustment rate corresponding to the discharge power of the master's battery pack, which is adjusted based on the demand for the dynamic response of the actual load, 0 < Ki ≤1. The larger Ki is, the faster the response at the moment of sudden change of the load, and the shorter the time required for the adjustment of the output voltage. The smaller Ki is, the longer the time required for the adjustment of the output voltage becomes, and the adjustment process becomes smoother.

[0015] The slave adopts a constant voltage control method for the AC output voltage outer loop of the dual-loop control method, and the AC output target voltage of the slave is expressed by the following formula: <> JPEG2026500128000007.jpg536 Here, VAC Ref_M2 is the slave's AC output voltage target value, and VAC rated is the system AC rated output voltage.

[0016] This application further provides an electronic device comprising at least one processor and a memory communicatively connected to the at least one processor, wherein the memory stores commands executable by the at least one processor, and the commands enable the at least one processor to execute the charge and discharge control method of the multi-machine parallel energy storage system as described above.

[0017] The present application further provides a non-volatile computer storage medium having stored thereon computer-executable instructions, the computer-executable instructions being executed by one or more processors such that the one or more processors can execute the method for controlling charging and discharging of a multi-machine parallel energy storage system as described above.

[0018] In the prior art, only AC parallel discharging can be realized when multiple energy storage devices are connected in parallel. In contrast to this, in the present application, when the AC sides of multiple energy storage devices are connected in parallel, the current state of the multi-machine parallel energy storage system is determined based on the first data, second data, and third data. If the current state meets the charging conditions, the energy storage system is charged according to the principle of master first and slave last while maintaining the connection relationship between the renewable energy device and the current energy storage device in the system, thereby realizing charging via AC bus. By simply connecting one set / single channel of renewable energy devices, the function of automatically charging the multiple energy storage devices can be realized. [Brief explanation of the drawings]

[0019] One or more embodiments are illustratively described in the accompanying drawings, which do not limit the embodiments, and in which like reference numerals represent similar elements and in which the figures are not to scale unless otherwise specified. [Figure 1] 1 is a schematic diagram of a multi-machine parallel energy storage system according to an embodiment of the present application; FIG. [Figure 2] FIG. 1 is an operation mode block diagram of a multi-machine parallel energy storage system according to an embodiment of the present application. [Figure 3] FIG. 1 is a block diagram of AC output control in a non-discharging state of a master in a multi-machine parallel energy storage system according to an embodiment of the present application. [Figure 4] FIG. 1 is a block diagram of AC output control in a discharging state of the master in a multi-machine parallel energy storage system according to an embodiment of the present application. [Figure 5] FIG. 1 is a charging control block diagram of a slave in a multi-machine parallel energy storage system according to an embodiment of the present application. [Figure 6] FIG. 2 is a schematic diagram of the charge / discharge control flow of the multi-machine parallel energy storage system according to an embodiment of the present application. [Figure 7] 1 is a schematic diagram illustrating the configuration of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0020] In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be described in more detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to illustrate the present application and are not used to limit the present application.

[0021] It should be noted that the features in the embodiments of the present application may be combined with each other if they do not conflict, and all are within the scope of protection of the present application. Also, although the schematic diagram of the device is divided into functional modules and the flowchart shows a logical procedure, in some cases the steps shown or described may be performed in a different manner or procedure from the module division in the schematic diagram of the device or the procedure in the flowchart.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art of this application. The terms used in the description of this application are only for the purpose of describing specific embodiments and are not intended to limit the scope of this application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0023] Energy storage device: An energy storage conversion device, consisting of key components such as an energy conversion unit (e.g., a bidirectional converter), an energy storage unit (energy storage battery), an energy management unit, and a safety system, which can charge the energy storage battery using photovoltaic power / commercial power, etc., and can power loads (refrigerators, TVs, power tools, smart terminals, etc.) in an off-grid state. The energy storage device itself can operate independently.

[0024] Renewable energy devices: include photovoltaic / wind / hydroelectric power generation devices, such as photovoltaic cell panels, wind power generators, etc. The following description will take the photovoltaic cell panels as an example.

[0025] See FIG. 1 for a multi-machine parallel energy storage system 100 according to an embodiment of the present application. The multi-machine parallel energy storage system 100 includes a photovoltaic cell panel 10, at least two energy storage devices (e.g., energy storage device 1 to energy storage device n, where n≧2, in FIG. 1 ), an AC bus 30, and a load 40. The photovoltaic cell panel 10 is connected to one of the energy storage devices (e.g., energy storage device 1 is selected and connected to the photovoltaic cell panel 10 in FIG. 1 ). The at least two energy storage devices are connected to the load 40 via the AC bus 30. The AC bus 30 includes a power line, which includes a live line and a dead line, and is used for power connection between the energy storage devices. Data is exchanged between the energy storage devices via wired or wireless communication (not shown), and may be via a communication method such as a controller area network (CAN), WIFI (wireless network communication technology), Bluetooth (registered trademark), or serial interface.

[0026] When the photovoltaic cell panel 10 is connected to any one of the at least two energy storage devices, the energy storage device connected to the photovoltaic cell panel 10 is identified as the master 21, and the energy storage device not connected to the photovoltaic cell panel 10 is identified as the slave 22. Specifically, when the photovoltaic cell panel 10 is connected to the energy storage device 1, if the energy storage device 1 detects that the PV voltage signal of the PV port satisfies a first voltage range (for example, 50V to 200V, 10V to 150V, etc., and this first voltage range can be determined according to the actual situation), the energy storage device 1 is automatically identified as the master 21, and simultaneously communicates with the other energy storage devices, identifying the energy storage devices 2 to n as slaves 22.

[0027] The configuration and functions of both the master and slave energy storage devices are the same. Specifically, each energy storage device includes a photovoltaic controller, a battery pack, a control unit, and a bidirectional converter. The control unit is connected to the photovoltaic controller, battery pack, and bidirectional converter. The photovoltaic controller is one of the core components of a photovoltaic power generation system. It mainly detects the connection of photovoltaic cell panels and uses an MPPT maximum power tracking algorithm to charge the current energy storage device with solar energy. At the same time, it has the following functions: 1) preventing overcharging or over-discharging of the battery pack and extending its lifespan; 2) preventing reverse polarity connection of the photovoltaic cell panel array and storage battery; and 3) preventing damage caused by lightning strikes. The battery pack is used to store or release electrical energy. The control unit is for controlling each unit / module in the energy storage device and communicating with other energy storage devices, and includes one or more processors, memory, and one or more programs. The control unit is the same for each energy storage device, but the programs and / or functions called may differ between the master and slave. The bidirectional converter is for conversion including DC-AC and AC-DC.

[0028] Specifically, as shown in FIG. 1, the master 21 includes a main control unit 211, a main photovoltaic power controller 212, a main battery pack 213, and a main bidirectional converter 214, and the slave 22 includes a sub control unit 221, a sub photovoltaic power controller 222, a sub battery pack 223, and a sub bidirectional converter 224.

[0029] An input terminal of the main photovoltaic power controller 212 is connected to the photovoltaic cell panel 10, an output terminal of the main photovoltaic power controller 212 is connected to a first terminal of the main battery pack 213, a second terminal of the main battery pack 213 is connected to a first terminal of the main bidirectional converter 214, and a second terminal of the main bidirectional converter 214 is connected to the load 40 via the AC bus 30, and a main control unit 211 is connected to the main photovoltaic power controller 212, the main battery pack 213, and the main bidirectional converter 214, respectively. Here, the main control unit 211 is for transmitting data with the slave control unit 221 and controlling the operating states of the main photovoltaic power controller 212, the main battery pack 213, and the main bidirectional converter 214.

[0030] A first end of the slave bidirectional converter 224 is connected to a second end of the slave battery pack 223, a second end of the slave bidirectional converter 224 is connected to a load 40 via an AC bus 30, and a first end of the slave battery pack 223 is connected to the slave photovoltaic power controller 222. A slave control unit 221 is connected to the slave photovoltaic power controller 222, the slave battery pack 223, and the slave bidirectional converter 224, respectively, and the slave control unit 221 is for transmitting data with the master control unit 211 and controlling the operating states of the slave photovoltaic power controller 222, the slave battery pack 223, and the slave bidirectional converter 224.

[0031] The main control unit 211 in the master is used to: firstly, dynamically obtain the first data of the master, the second data of the slaves 22, and the third data of the photovoltaic cell panels 10; then, determine the current state of the multi-machine parallel energy storage system 100 based on the first data, the second data, and the third data; then, if the current state meets the charging condition, control the photovoltaic cell panels 10 to supply electrical energy to the master 21; when the master 21 is fully charged, control the photovoltaic cell panels 10 to supply electrical energy to the slaves 22 via the master 21, that is, control the photovoltaic cell panels 10 to supply electrical energy to the master 21, and simultaneously control the master 21 to supply electrical energy to the slaves 22.

[0032] In some embodiments, the first data of the master 21 includes the battery capacity of the master 21 and the load power of the master 21, etc., the second data of the slave 22 includes the battery capacity of the slave 22 and the load power of the slave 22, etc., and the third data of the photovoltaic panel 10 includes the generated power P pv Includes.

[0033] Based on the first data and the second data, the total power P of the master and slave loads is calculated. Load Then, calculate the total power of the load P Load , the third data of the generated power P pv and the master's battery capacity SOC to determine the operation mode of the multi-machine parallel energy storage system 100.

[0034] Please refer to Figure 2. Figure 2 is an operation mode block diagram of a multi-machine parallel energy storage system according to an embodiment of the present application. After the photovoltaic cell panels 10 are connected to the master 21, the master 21 dynamically acquires the first data of the master 21, the second data of the slave 22 and the third data of the photovoltaic cell panels 10, and calculates the total power P of the load. Load and generated power P pv P pv >P LoadIf it is not, it is determined that the current state does not meet the charging conditions, so the system enters AC parallel discharging mode, that is, it controls the photovoltaic cell panel 10 to supply electrical energy to the load, and the master 21 and slave 22 are both discharging for use by the load; if it is positive, it is determined that the current state meets the charging conditions, and it further determines whether the master 21 is fully charged; if the master is not fully charged, it enters standalone charging mode, that is, it controls the photovoltaic cell panel 10 to supply electrical energy to the master 21; once the master is fully charged, it enters AC bus charging mode, that is, it controls the photovoltaic cell panel 10 to supply electrical energy to the master 21, and at the same time controls the master 21 to supply electrical energy to the slave 22.

[0035] In AC parallel discharge mode, the total power output of the multi-machine parallel energy storage system 100 is equal to the total power P Load Current PV power generation P Pv minus P Load -P Pv is.

[0036] Regarding the standalone charging mode and AC bus charging mode after the current state meets the charging conditions as described above, the essence is to charge according to the principle of master first and slave last. The basis for determining whether the master is fully charged is whether its battery capacity exceeds a set threshold. For example, if the battery capacity of the master 21 exceeds 80% or 100%, the master 21 is considered to be fully charged, and conversely, the master 21 is considered not to be fully charged. When the master is fully charged, the photovoltaic cell panel 10 is controlled to charge the slave 22 by the master 21. The power that the photovoltaic cell panel 10 charges the master or slave is the generated power P of the photovoltaic cell panel 10. Pv to the total power P of the load Load minus P Pv -P Load is equal to.

[0037] When the system has at least three energy storage devices, that is, when the system has multiple slaves, the slaves are charged in sequence according to a predetermined rule, where the predetermined rule can be in the order of the slaves' electric power amounts from smallest to largest, or in the order of the slaves' electric power amounts from largest to smallest, or in the order of the slave addresses, etc.

[0038] During the operation of the multi-machine parallel energy storage system 100, the master monitors the operating status of all energy storage devices and photovoltaic cell panels 10, and when the connection status of the photovoltaic cell panels, the photovoltaic generated power, and the load 40 change, it adjusts the operating status of the multi-machine parallel energy storage system 100 in a timely manner to prioritize and ensure the demand for electrical power supply.

[0039] The multi-machine parallel energy storage system 100 adopts a dual-loop control method of an AC output voltage outer loop and an inverter current inner loop. For the AC output voltage outer loop, the master and slave are specifically as follows:

[0040] Please refer to Figures 3 and 4. Figure 3 is a block diagram of AC output control in a non-discharging state of the master in a multi-machine parallel energy storage system according to an embodiment of the present application, and Figure 4 is a block diagram of AC output control in a discharging state of the master in a multi-machine parallel energy storage system according to an embodiment of the present application. For the energy storage device 1 (i.e., the master 21) connected to the photovoltaic battery panel 10 in the multi-machine parallel energy storage system, the photovoltaic generation power and the battery discharge power are introduced as feedforward control into the AC output voltage outer loop of the dual-loop control method, thereby realizing power control of photovoltaic charging and AC parallel discharging.

[0041] After being connected to the photovoltaic battery panel 10, the master 21 performs maximum power point tracking (MPPT) control and simultaneously adjusts its AC output voltage based on the photovoltaic power. The AC output target voltage of the master is expressed by the following formula: JPEG2026500128000008.jpg Equation (1) Here, VAC Ref_M1 is the target value of the master's AC output voltage, VAC rated is the rated AC output voltage of the system, P PV is the generated power of the current renewable energy device, P rated is the rated power of the system, ΔU is the AC output voltage adjustment amount, and it is correlated with the discharge power of the master's battery pack.

[0042] JPEG2026500128000009.jpg Equation (2) Here, P discharge is the discharge power of the master's battery pack, Ki is the coefficient of the output voltage adjustment rate corresponding to the discharge power of the master's battery pack, and it is adjusted based on the requirements of the dynamic response of the actual load. 0 < Ki ≤ 1. The larger Ki is, the faster the response at the moment of rapid load change, and the shorter the time required for output voltage adjustment. The smaller Ki is, the longer the time required for output voltage adjustment, and the smoother the adjustment process becomes.

[0043] Referring to FIG. 3, Equation (1) and Equation (2), the generated power P pv of the current renewable energy device meets the current charging and load driving power requirements of the multi - machine parallel energy storage system, and the master's battery pack (i.e., the main battery pack 213) is in a non - discharging state. At this time, P discharge = 0 W, ΔU = 0, and the master's AC output voltage gradually increases with the increase in the generated power P <s pv of the current renewable energy device. Referring to FIG. 4, Equation (1) and Equation (2), the generated power P pvHowever, the current charging and load driving power requirements of the multi-machine parallel energy storage system cannot be met, and the master battery pack (i.e., the main battery pack 213) enters a discharging state. At this time, P discharge >0 W, and it can be seen from equation (2) that ΔU<0 W, and the AC output voltage of the master gradually decreases along with the discharge power of the master battery pack.

[0044] Please refer to Figure 5. Figure 5 is a block diagram of charging control of a slave in a multi-machine parallel energy storage system according to an embodiment of the present application. For the energy storage devices 2 to n (i.e., slaves 22) connected to the photovoltaic cell panel 10 in the multi-machine parallel energy storage system, a constant voltage control method is adopted for the AC output voltage outer loop of the dual loop control method, and charging is achieved by the AC bus. The voltage outer loop target voltage of the slave, i.e., the AC output target voltage of the slave, is expressed by the following equation: JPEG2026500128000010.jpg536 formula (3) Here, VAC Ref_M2 is the slave's AC output voltage target value, and VAC rated is the rated AC output voltage of the system.

[0045] Referring to FIG. 1, as can be seen from equation (3) and FIG. 5, the voltage at the AC bus common point PCC>VAC rated The slave is charged via the AC bus, and the charging is realized through the route of the photovoltaic cell panel - master - AC parallel bus - slave, and the voltage of the AC bus common point PCC <VAC rated If so, the slave battery pack (ie, the secondary battery pack 223) discharges through the AC bus to drive the load.

[0046] 3 and 4, the AC output target voltage of the master obtained by the formula (1) and the actual voltage VAC of the AC bus are outThe voltage error value is calculated by subtracting the reference current I from the master inverter current inner loop using a proportional-integral regulator. InvRef_M1 and then obtain the actual inverter current I Inv_M1 The difference between these values ​​is calculated to obtain a current error value, and a modulating wave is obtained by a proportional-integral regulator to control the on / off of the electronically controllable power element.

[0047] Referring to FIG. 5, the slave AC output target voltage obtained by equation (3), i.e., the system AC rated output voltage and the actual voltage VAC of the AC bus, out The voltage error value is calculated by calculating the difference between the two, and the reference current I InvRef_M2 and then obtain the actual inverter current I Inv_M2 The difference between these values ​​is calculated to obtain a current error value, and a modulating wave is obtained by a proportional-integral regulator to control the on / off of the electronically controllable power element.

[0048] When the entire multi-machine parallel energy storage system meets the charging requirements, the operation steps are as follows: 1) When the master 21 connected to the photovoltaic cell panel 10 is not fully charged, the system enters a standalone charging mode and performs standalone charging; 2) After the master is fully charged, the system enters AC bus charging mode, the master performs photovoltaic-AC parallel discharge, controls the photovoltaic power and outputs it to the AC bus, and the voltage of the AC bus common point PCC rises; 3) The slave starts AC constant voltage control and the constant voltage target JPEG2026500128000011.jpg536, which detects an increase in port voltage and controls the slave with a constant AC voltage to perform AC parallel charging.

[0049] The master connected to the photovoltaic cell panel 10 adopts photovoltaic power to perform feedforward control, so that the photovoltaic output power increases / decreases, the discharge output voltage of the master's AC port increases / decreases, and the charging power of the slave is increased / decreased by the AC bus.

[0050] The master connected to the photovoltaic battery panel 10 also simultaneously uses the discharge power of the main battery pack to perform feedforward control. When the main battery pack discharges, it actively reduces the discharge output voltage of the master's AC port, and the charging power of the master is reduced by the AC bus. While maintaining the connection relationship between the renewable energy device and the current energy storage device in the system, the energy storage system is charged according to the principle of master first and slave last.

[0051] It should be understood that the above examples only exemplify photovoltaic power generating devices - photovoltaic cell panels, but may also be renewable energy devices such as wind / hydro power generating devices.

[0052] Please refer to Figure 6. Figure 6 is a schematic flow diagram of a charge / discharge control method for a multi-machine parallel energy storage system according to an embodiment of the present application. This charge / discharge control method is applied to the multi-machine parallel energy storage system 100 as described above, and the method includes the following steps: Step S1: dynamically obtain first data of a master, second data of a slave, and third data of a renewable energy device. Step S2: determining a current state of the multi-machine parallel energy storage system based on the first data, the second data, and the third data; Step S3: If the current state satisfies the charging condition, control the renewable energy device to supply electrical energy to the master 21. Step S4: When the master is fully charged, the renewable energy device is controlled to supply electrical energy to the slave by the master.

[0053] Here, step S2 includes the following steps. Step S21: Calculate the total power of the loads of the multi-machine parallel energy storage system according to the first data and the second data. Step S22: Determine whether the third data including the power generated by the renewable energy device is greater than the total power of the loads. Step S23: if the third data is greater than the total power of the load, it is determined that the current state satisfies the charging condition. Step S24: If the third data is equal to or less than the total power of the load, it is determined that the current state does not satisfy the charging condition.

[0054] After determining that the current state does not satisfy the charging condition, in step S5, the renewable energy device is controlled to supply electrical energy to the load, and at the same time, the master and slave are discharged in parallel to supply power to the load.

[0055] In the above control method, the system adopts a dual-loop control method consisting of an output voltage outer loop and an inverter current inner loop.

[0056] The master introduces the photovoltaic power generation power and the battery discharge power as feedforward control into the AC output voltage outer loop of the dual loop control method, and the AC output target voltage of the master is expressed by the following equation: JPEG2026500128000012.jpg1068 formula (1) JPEG2026500128000013.jpg1037 formula (2) Here, VAC Ref_M1 is the master AC output voltage target value, and VAC rated is the rated AC output voltage of the system, and P PV is the power generated by the current renewable energy device, and P rated is the system rated power, ΔU is the output voltage adjustment amount, which is correlated with the discharge power of the master battery pack, and P dischargeis the discharge power of the master battery pack, Ki is the output voltage adjustment rate coefficient corresponding to the discharge power of the master battery pack, which is adjusted based on the actual load dynamic response demand, and 0 <Ki≦1である。

[0057] The slave employs a constant voltage control method for the AC output voltage outer loop of the dual loop control method, and the AC output target voltage of the slave is expressed by the following equation: JPEG2026500128000014.jpg536 Here, VAC Ref_M2 is the slave's AC output voltage target value, and VAC rated is the rated AC output voltage of the system.

[0058] For technical details not described in detail in the charge / discharge control method for a multi-machine parallel energy storage system, please refer to the multi-machine parallel energy storage system according to the above-mentioned embodiment of the present application.

[0059] In the multi-machine parallel energy storage system and the charge / discharge control method thereof according to the embodiments of the present application, when multiple energy storage devices are connected in parallel, simply connecting one set / single channel renewable energy device can realize the function of automatically charging the multiple energy storage devices.

[0060] FIG. 7 is a schematic diagram of an electronic device 200 according to an embodiment of the present application. As shown in FIG. 7, the electronic device 200 includes one or more processors 201 and a memory 202. In FIG. 7, one processor 201 is used as an example.

[0061] The processor 201 and the memory 202 may be connected by a bus or other means, and FIG. 7 shows an example in which they are connected by a bus.

[0062] The memory 202 can be used as a non-volatile computer-readable storage medium to store non-volatile software programs, non-volatile computer-executable programs and modules. The processor 201 executes the non-volatile software programs, commands and units stored in the memory 202 to perform various functional applications and data processing of the electronic device 200, that is, to realize the charge / discharge control method for a multi-machine parallel energy storage system according to the embodiment.

[0063] Memory 202 may include a program storage area and a data storage area, where the program storage area may store an operating system and / or application programs required for at least one function, and the data storage area may store data generated based on use of electronic device 200. Note that memory 202 may include high-speed random access memory and / or non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 202 may optionally include memory located remotely from processor 201, and these remote memories may be connected to electronic device 200 via a network. Examples of such networks include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0064] The one or more units are stored in the memory 202 and executed by the one or more processors 201 to implement the charge / discharge control method for a multi-machine parallel energy storage system in any of the method embodiments described above.

[0065] The electronic device 200 can execute the method for controlling charging and discharging of a multi-machine parallel energy storage system according to an embodiment of the present application, and has a program module and beneficial effects corresponding to executing the method. For technical details not described in detail in the embodiment of the electronic device 200, please refer to the method for controlling charging and discharging of a multi-machine parallel energy storage system according to an embodiment of the present application.

[0066] The electronic devices of the embodiments of the present application may exist in a variety of forms, including but not limited to the following: (1) Ultra-Mobile Personal Computer Devices: These devices fall under the category of personal computers and have computing and processing capabilities, and generally also have mobile Internet access features. Such devices include PDAs, MIDs, and UMPC devices, such as the iPad. (2) Server: A device that provides computing services. The server configuration includes a processor, hard disk, internal storage device, system bus, etc. Although the server is similar to a general-purpose computer architecture, it must provide highly reliable services, and therefore has high requirements in terms of processing power, stability, reliability, security, scalability, and manageability. (3) Other electronic devices.

[0067] It should be noted that the above-described device embodiments are merely illustrative, and the units described therein as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, i.e., they may be located at a certain location or distributed across multiple network units. Some or all of the modules may be selected according to actual needs to achieve the objectives of the solutions of the present embodiments.

[0068] From the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be realized by combining software with a general-purpose hardware platform, and of course, by hardware. Those skilled in the art can understand that all or part of the flow of the method in the above embodiments can be realized by a computer program giving commands to related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program can include the flow of each method embodiment. Here, the storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), etc.

[0069] The embodiments of the present application further provide a non-volatile computer-readable storage medium, which may be included in the device described in the above embodiments or may exist independently of the device, carrying one or more programs that, when executed, implement the methods of the embodiments of the present disclosure.

[0070] Finally, it should be noted that the above examples are only for illustrating the technical solutions of the present application, and are not intended to limit the same. In the belief of the present application, the technical features in the above examples or different examples can be combined, and steps can be implemented in any order. There are many other variations in different aspects of the present application as described above, which, for the sake of brevity, are not provided in detail. Although the present application has been described in detail with reference to the above examples, those skilled in the art can still amend the technical solutions described in the above examples or make equivalent substitutions for some of the technical features therein, and it should be understood that these amendments and substitutions will not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A multi-machine parallel energy storage system, comprising: a single-channel renewable energy device; at least two energy storage devices; an AC bus; and a load, wherein the renewable energy device is for connecting to one of the at least two energy storage devices, and AC outputs of the at least two energy storage devices are connected to the load via the AC bus; When the renewable energy device is connected to any one of the at least two energy storage devices, identifying the energy storage device connected to the renewable energy device as a master and identifying the energy storage device not connected to the renewable energy device as a slave; The master dynamically acquiring first data of the master, second data of the slave, and third data of the renewable energy device; determining a current state of the multi-machine parallel energy storage system based on the first data, the second data, and the third data; If the current state satisfies a charging condition, controlling the renewable energy device to supply electrical energy to the master; When the master is fully charged, the master controls the renewable energy device to supply electrical energy to the slave.

2. Determining a current state of the multi-machine parallel energy storage system based on the first data, the second data, and the third data includes: calculating a total power of loads of the multi-machine parallel energy storage system based on the first data and the second data; Determining whether the third data including the power generated by the renewable energy device is greater than a total power of the load; determining that the current state satisfies the charging condition when the third data is greater than the total power of the load; and determining that the current state does not satisfy the charging condition if the third data is equal to or less than a total power of the loads.

3. 3. The multi-machine parallel energy storage system of claim 2, further comprising: after determining that the current state does not satisfy the charging condition, controlling the renewable energy device to supply electrical energy to the load, and simultaneously discharging the master and the slave in parallel to supply power to the load.

4. The multi-machine parallel energy storage system according to claim 1, characterized in that the system adopts a dual-loop control method of an AC output voltage outer loop and an inverter current inner loop.

5. The master introduces the photovoltaic power generation power and the battery discharge power as feedforward control into the AC output voltage outer loop of the dual-loop control system, and the AC output target voltage of the master is expressed by the following equation: Here, VAC Ｒｅｆ＿Ｍ１ is the master AC output voltage target value, and VAC ｒａｔｅｄ is the system AC rated output voltage, and P ＰＶ is the power generated by the current renewable energy device, and P ｒａｔｅｄ is the system rated power, ΔU is the AC output voltage adjustment amount, which is correlated with the discharge power of the master battery pack, and P ｄｉｓｃｈａｒｇｅ 5. The multi-machine parallel energy storage system of claim 4, wherein K is the discharge power of the master battery pack, K is the coefficient of the output voltage adjustment rate corresponding to the discharge power of the master battery pack, and 0<K≦1.

6. The slave employs a constant voltage control method for an AC output voltage outer loop of the dual loop control method, and an AC output target voltage of the slave is expressed by the following equation: Here, VAC Ｒｅｆ＿Ｍ２ is the slave's AC output voltage target value, and VAC ｒａｔｅｄ 5. The multi-machine parallel energy storage system of claim 4, wherein: is the system AC rated output voltage.

7. When there are at least three energy storage devices, the slave includes at least two of the energy storage devices, and the master further 7. The multi-machine parallel energy storage system according to claim 1, wherein when the master is fully charged, the charging order of the slaves is determined according to a predetermined rule, and the renewable energy devices are controlled based on the charging order to supply electrical energy to the slaves by the master.

8. A charge / discharge control method for a multi-machine parallel energy storage system, the multi-machine parallel energy storage system including: a single-channel renewable energy device; at least two energy storage devices; an AC bus; and a load; the renewable energy device is connected to one of the at least two energy storage devices; and AC output terminals of the at least two energy storage devices are connected to the load via the AC bus; When the renewable energy device is connected to any one of the at least two energy storage devices, identifying the energy storage device connected to the renewable energy device as a master and identifying the energy storage device not connected to the renewable energy device as a slave; The charge / discharge control method of the system includes: dynamically acquiring first data of the master, second data of the slave, and third data of the renewable energy device; determining a current state of the multi-machine parallel energy storage system based on the first data, the second data, and the third data; If the current state satisfies a charging condition, controlling the renewable energy device to supply electrical energy to the master; and when the master is fully charged, controlling the renewable energy device to supply electrical energy to the slaves by the master.

9. The charge / discharge control method of the system includes:

9. The method for controlling the charging and discharging of a multi-machine parallel energy storage system according to claim 8, wherein the system adopts a dual-loop control method of an output voltage outer loop and an inverter current inner loop.

10. The master introduces the photovoltaic power generation power and the battery discharge power as feedforward control into the AC output voltage outer loop of the dual-loop control system, and the AC output target voltage of the master is expressed by the following equation: Here, VAC Ｒｅｆ＿Ｍ１ is the master AC output voltage target value, and VAC ｒａｔｅｄ is the system AC rated output voltage, and P ＰＶ is the power generated by the current renewable energy device, and P ｒａｔｅｄ is the system rated power, ΔU is the output voltage adjustment amount, which is correlated with the discharge power of the master battery pack, and P ｄｉｓｃｈａｒｇｅ is the discharge power of the master battery pack, Ki is the coefficient of the output voltage adjustment rate corresponding to the discharge power of the master battery pack, and 0<Ki≦1; The slave employs a constant voltage control method for an AC output voltage outer loop of the dual loop control method, and an AC output target voltage of the slave is expressed by the following equation: Here, VAC Ｒｅｆ＿Ｍ２ is the slave's AC output voltage target value, and VAC ｒａｔｅｄ 10. The method for controlling charging and discharging of a multi-machine parallel energy storage system according to claim 9, wherein is the system AC rated output voltage.

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