Battery SOC balancing control method, parallel inverter system, device, and medium

Abstract

The present invention relates to the technical field of industrial control, and in particular to a battery SOC balancing control method, a parallel inverter system, a device, and a medium. The battery SOC balancing control method comprises: according to a preset balancing cycle, the current inverter acquiring an actual battery SOC of a high-voltage battery connected to the current inverter, and providing the actual battery SOC to a preset master unit, so as to acquire an average SOC provided by the preset master unit on the basis of the actual battery SOC; acquiring an SOC difference between the actual battery SOC and the average SOC, and acquiring a current correction value on the basis of the SOC difference; and acquiring a charge / discharge state of a parallel inverter system and a battery current threshold of the high-voltage battery, and on the basis of the charge / discharge state, correcting the battery current threshold using the current correction value to acquire a final current threshold. The present invention improves the SOC balance of a parallel inverter system, avoids excessive load on some inverters, and reduces the risk of failure, thereby enhancing the stability and reliability of the parallel inverter system.

Description

Battery SOC equalization control method, inverter parallel system, device and medium TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial control, in particular to a battery SOC equalization control method, an inverter parallel system, a device and a medium. BACKGROUND

[0002] In a grid-connected inverter parallel system, each inverter needs to be connected to a battery module. Due to factors such as illumination angle, illumination intensity, and number of photovoltaic panels, there will be some differences in the photovoltaic side power of each inverter. At the same time, the hardware parameters and working characteristics of each inverter parallel system will also be different. These factors cause the battery SOC of different battery modules to deviate within a certain period of time.

[0003] When the SOC of the battery connected to a certain inverter drops to the discharge cutoff point, the load of the entire parallel system needs to be shared by other online inverters. If the system only has two inverters, all the load needs to be provided by the other inverter, which will cause the load rate of the other inverter to increase sharply, even triggering overload protection, and eventually causing the entire system to power off. TECHNICAL PROBLEM

[0004] The technical problem to be solved by the embodiments of the present application is to provide a battery SOC equalization control method, an inverter parallel system, a device and a medium to solve the load imbalance problem caused by SOC deviation accumulation in the prior art. TECHNICAL SOLUTION

[0005] The present application discloses a battery SOC equalization control method applied to an inverter parallel system, the inverter parallel system comprising at least two groups of battery modules, each battery module comprising an inverter, a photovoltaic panel and a high-voltage battery connected to the inverter, and the inverters of adjacent two groups of battery modules being connected to each other.

[0006] The battery SOC equalization control method comprises the following steps:

[0007] According to a preset equalization period, the current inverter obtains the actual battery SOC of the high-voltage battery connected thereto, and provides the actual battery SOC to a preset host computer to obtain an average SOC provided by the preset host computer according to the actual battery SOC.

[0008] An SOC difference value between the actual battery SOC and the average SOC is obtained, and a current correction value is obtained based on the SOC difference value.

[0009] Obtaining the charge-discharge state of the inverter parallel system and the battery current threshold of the high-voltage battery, correcting the battery current threshold by the current correction value based on the charge-discharge state to obtain a final current threshold.

[0010] Optionally, the step of correcting the battery current threshold by the current correction value based on the charge-discharge state comprises:

[0011] If the current is in the grid-connected charging state, the final current threshold is obtained by subtracting the current correction value from the battery current threshold;

[0012] If the current is in the grid-connected discharging state, the final current threshold is obtained by adding the current correction value to the battery current threshold.

[0013] Optionally, after the step of obtaining the final current threshold, comprising:

[0014] Obtaining the inverter current threshold of the current inverter, taking the minimum of the inverter current threshold and the battery current threshold as a target threshold, and limiting the final current threshold by the target threshold so that the final current threshold is between 0 and the target threshold.

[0015] Optionally, if the current is in the grid-connected charging state, after the step of obtaining the final current threshold, further comprising:

[0016] Obtaining the photovoltaic charging power of the photovoltaic panel connected to itself, obtaining the current charging power according to the final current threshold, and obtaining the excess charging amount based on the photovoltaic charging power and the current charging power;

[0017] Transmitting the excess charging amount to the micro-grid of the inverter parallel system, so that other inverters can obtain at least part of the excess charging amount from the micro-grid to charge the corresponding high-voltage battery of the other inverters; or

[0018] After the step of obtaining the final current threshold, further comprising:

[0019] When the current charging power is higher than the photovoltaic charging power, at least part of the excess charging amount is obtained from the micro-grid according to the difference between the photovoltaic charging power and the current charging power, and at least part of the excess charging amount is provided to the corresponding high-voltage battery.

[0020] Optionally, the step of obtaining the excess charging amount from the micro-grid comprises:

[0021] Obtaining a total discharge current limiting value, and obtaining an average discharge current limiting value according to the total discharge current limiting value;

[0022] At least part of the excess charging capacity is obtained from the micro-grid at a current lower than the average discharge current limit value.

[0023] Optionally, the step of obtaining the current correction value based on the SOC difference value comprises:

[0024] Optionally, the step of obtaining the current correction value based on the SOC difference value comprises:

[0025] Optionally, the step of providing the actual SOC of the battery to the preset host comprises:

[0026] Optionally, the step of providing the actual SOC of the battery to the preset host comprises:

[0027] Optionally, the step of providing the actual SOC of the battery to the preset host comprises:

[0028] The inverter is used to implement the battery SOC balancing control method as described above.

[0029] A computer readable storage medium stores a computer program, and the computer program, when executed by a processor, causes the processor to perform the steps of the method as described above.

[0030] A power supply device comprises a memory and a processor, and the memory stores a computer program, and the computer program, when executed by the processor, causes the processor to perform the steps of the method as described above. Advantages

[0031] Compared with the prior art, the battery SOC balancing control method provided by the embodiment has the advantages that: the average SOC is calculated according to the actual SOC of each battery module, each inverter can calculate the difference between the actual SOC and the average SOC, and obtain a current correction value based on the difference, and the current correction value is used to adjust the battery current threshold value according to the charging and discharging state of the inverter parallel system and the battery current threshold value of the high-voltage battery, to obtain a final current threshold value, which can be adjusted in real time according to the actual situation, helps to control the charging speed of each high-voltage battery, improves the balance of the SOC of the inverter parallel system, avoids excessive load of part of the inverters, reduces the risk of failure, and thus enhances the stability and reliability of the inverter parallel system. BRIEF DESCRIPTION OF DRAWINGS

[0032] The scheme of the present application will be further described in detail below with reference to the accompanying drawings and embodiments, and the drawings show:

[0033] Fig. 1 is a flowchart of an embodiment of the battery SOC equalization control method provided by the present application;

[0034] Fig. 2 is a structural diagram of an inverter parallel system provided by the present application;

[0035] Fig. 3 is a flowchart of another embodiment of the battery SOC equalization control method provided by the present application;

[0036] Fig. 4 is a flowchart of still another embodiment of the battery SOC equalization control method provided by the present application;

[0037] Fig. 5 is a structural diagram of an embodiment of the energy supply device provided by the present application;

[0038] Fig. 6 is a structural diagram of an embodiment of the computer readable storage medium provided by the present application.

[0039] The reference signs in the drawings are as follows:

[0040] 10, inverter parallel system; 11, battery module; 111, inverter; 112, photovoltaic panel; 113, high-voltage battery; 20, energy supply device; 21, processor; 22, memory; 30, computer readable storage medium; 31, computer program. Best Mode for Carrying Out the Invention

[0041] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The preferred embodiments of the present application will be described in detail with reference to the drawings.

[0042] Please refer to Figs. 1 and 2. Fig. 1 is a flowchart of an embodiment of the battery SOC equalization control method provided by the present application. Fig. 2 is a structural diagram of an inverter parallel system provided by the present application. As shown in Fig. 2, the inverter parallel system 10 includes at least two battery modules 11. Each battery module 11 includes an inverter 111, a photovoltaic panel 112 connected to the inverter 111, and a high-voltage battery 113 connected to the inverter 111. The inverter 111 is used to convert the direct current power stored in the high-voltage battery 113 into alternating current power for use by off-grid devices, and is also used to convert the direct current power stored in the high-voltage battery 113 into alternating current power and connect it to the power grid for use by the power grid.

[0043] The inverter 111 parallel system in the embodiment supports off-grid mode and grid-connected mode. In the off-grid mode, the inverter converts the direct current power of the high-voltage battery 113 into alternating current power for use by off-grid equipment. When the high-voltage battery 113 needs to be charged, the photovoltaic panel 112 can be used for charging. In the grid-connected mode, the inverter 111 converts the direct current power of the high-voltage battery 113 into alternating current power and connects to the power grid. In this mode, the inverter parallel system 10 can charge or supply power to the power grid, realizing bidirectional flow of power.

[0044] In the embodiment, each inverter 111 is connected to a corresponding high-voltage battery 113 and photovoltaic panel 112, which may cause the SOC of each high-voltage battery 113 to be unbalanced. Therefore, the SOC of the high-voltage battery 113 in each battery module 11 needs to be calibrated regularly to ensure that the deviation between them is as small as possible, so as to reduce the SOC deviation between different battery modules 11, improve the power supply reliability of the entire inverter parallel system 10 in the off-grid parallel mode, and prolong the power supply time to cope with sudden power grid outages and the like.

[0045] In the inverter parallel system shown in FIG. 2, the inverters 111 of the battery modules 11 of two adjacent groups are connected to each other and can communicate with each other to implement the method shown in FIG. 1. Specifically, the two inverters 111 are connected through a CAN communication bus, and the communication rate of the CAN bus is adjustable. In the embodiment, the bit stream is 250 kpbs.

[0046] The battery SOC equalization control method provided by the application comprises the following steps:

[0047] S101: The current inverter obtains the actual SOC of the high-voltage battery connected thereto, and provides the actual SOC to a preset host to obtain an average SOC provided by the preset host according to the actual SOC.

[0048] In a specific implementation scenario, the inverter parallel system shown in FIG. 2 comprises a plurality of inverters, each of which is connected to a corresponding high-voltage battery. One of the inverters is selected as a preset host, and the remaining inverters are slaves of the host. The host can obtain the actual SOC of the high-voltage battery connected thereto, and the slave obtains the actual SOC of the high-voltage battery connected thereto and transmits it to the preset host through the connection between them, so that the host can obtain the actual SOC of all high-voltage batteries in the inverter parallel system. The average SOC is obtained by adding all the actual SOCs and dividing by the number of high-voltage batteries. The host can distribute the average SOC to each slave through the connection between the inverters. Both the host and the slave can obtain the average SOC.

[0049] S102: Obtain a SOC difference value between the actual SOC of the battery and the average SOC, and obtain a current correction value based on the SOC difference value.

[0050] In one specific implementation scenario, for each inverter, the actual SOC of the high-voltage battery connected to the inverter is obtained, and the received / calculated average SOC is obtained. The SOC difference value between the actual SOC of the battery and the average SOC is obtained, which reflects the difference between the actual SOC of the battery and the average SOC. For example, if the SOC difference value is positive, it means that the actual SOC of the high-voltage battery exceeds the average SOC. If the battery is in a charging state, the charging power needs to be reduced, and if the battery is in a discharging state, the discharging power needs to be increased, thereby reducing the gap between the actual SOC of the battery and the average SOC. For another example, if the SOC difference value is negative, it means that the actual SOC of the high-voltage battery is lower than the average SOC. If the battery is in a charging state, the charging power needs to be increased, and if the battery is in a discharging state, the discharging power needs to be reduced, thereby reducing the gap between the actual SOC of the battery and the average SOC.

[0051] Based on the SOC difference value, a current correction value is obtained, which is used to correct the charging and discharging current of the high-voltage battery, thereby realizing the adjustment of the SOC of the high-voltage battery to reduce the gap between the SOCs of the high-voltage batteries.

[0052] In one embodiment, the current correction value can be obtained based on the proportional coefficient correction method according to the SOC difference value. The proportional coefficient is a pre-set parameter used to adjust the size of the current correction value. For example, the current correction value = proportional coefficient x SOC difference value.

[0053] In other implementation scenarios, the current correction value can also be obtained according to other methods. For example, the PID control method, the PID controller (proportional-integral-derivative controller) can calculate the current correction value according to the size of the SOC difference value combined with the proportional, integral and differential parts. The PID controller can be adjusted according to the real-time state of the system, and has good stability and dynamic performance. For another example, the fuzzy logic control method, the fuzzy logic controller can infer the corresponding current correction value according to the fuzzy rules and the input SOC difference value. Fuzzy logic can handle uncertainty and ambiguity. For another example, using neural network can input the SOC difference value as a feature according to the trained model, and output the corresponding current correction value. Neural network can learn complex nonlinear relationship, which is suitable for control problems requiring high precision and complexity.

[0054] S103: Obtain the charging and discharging state of the inverter parallel system and the battery current threshold of the high-voltage battery, and correct the battery current threshold based on the charging and discharging state using the current correction value to obtain the final current threshold.

[0055] In one specific implementation scenario, a battery current threshold of the high-voltage battery is obtained, the battery current threshold is used to limit the amplitude of the input / output current when the high-voltage battery is charging / discharging, and the battery current threshold is used to limit the amplitude of the input / output current to protect the use safety of the high-voltage battery.

[0056] In the present implementation scenario, the charging / discharging power of the high-voltage battery is adjusted by adjusting the amplitude of the input / output current to narrow the gap of the SOC of each high-voltage battery. According to the analysis in the foregoing, the power adjustment strategy for the high-voltage battery is inconsistent in the charging state and the discharging state, and therefore the adjustment of the current also needs to be set according to the specific charging / discharging state. Therefore, in the present embodiment, the charging / discharging state of the parallel inverter system is obtained, and based on the charging / discharging state, the battery current threshold is corrected by using a current correction value to obtain a final current threshold.

[0057] If the current is in the grid-connected charging state, the final current threshold is obtained by subtracting the current correction value from the battery current threshold. If the current is in the grid-connected discharging state, the final current threshold is obtained by adding the current correction value to the battery current threshold.

[0058] Specifically, if the current is in the grid-connected charging state and the SOC difference is positive, the corresponding current correction value is positive, the final current threshold obtained by subtracting the current correction value from the battery current threshold is smaller, so that the upper limit of the charging current of the high-voltage battery is reduced, and the charging power is reduced, so that the growth speed of the high SOC of the high-voltage battery is slowed down. The SOC difference is negative, the corresponding current correction value is negative, the final current threshold obtained by subtracting the current correction value from the battery current threshold is larger, so that the upper limit of the charging current of the high-voltage battery is increased, and the charging power is increased, so that the growth speed of the low SOC of the high-voltage battery is accelerated. In this way, by slowing down the growth speed of the high SOC and accelerating the growth speed of the low SOC, the SOC of all high-voltage batteries can be balanced.

[0059] If the current is in the grid-connected discharging state and the SOC difference is positive, the corresponding current correction value is positive, the final current threshold obtained by adding the current correction value to the battery current threshold is larger, so that the upper limit of the discharging current of the high-voltage battery is increased, and the discharging power is increased, so that the reduction speed of the high SOC of the high-voltage battery is accelerated. The SOC difference is negative, the corresponding current correction value is negative, the final current threshold obtained by adding the current correction value to the battery current threshold is smaller, so that the upper limit of the discharging current of the high-voltage battery is reduced, and the charging power is reduced, so that the reduction speed of the low SOC of the high-voltage battery is slowed down. In this way, by increasing the reduction speed of the high SOC and reducing the reduction speed of the low SOC, the SOC of all high-voltage batteries can be balanced. This strategy can ensure that the SOC of each battery module is in a relatively balanced state, and improve the performance and stability of the system.

[0060] In other implementation scenarios, each inverter has an inverter current threshold for limiting the current size of the inverter input / output to protect the inverter. In order to be able to protect the inverter and the high-voltage battery, for each battery module, the inverter current threshold of the inverter and the battery current threshold of the high-voltage battery are obtained, the minimum of the inverter current threshold and the battery current threshold is taken as a target threshold, and the target threshold is used to limit the final current threshold so that the final current threshold is between 0 and the target threshold. That is, if the final current threshold has not reached or is equal to the target threshold, the final current threshold remains unchanged, if the final current threshold is negative, it is set to 0 to ensure that there is no negative value. If the final current threshold has exceeded the target threshold, it is set to the size of the target threshold to avoid exceeding the set limit. In this way, the inverter and the high-voltage battery of each battery module can be effectively protected, so that each component can work normally, which helps to maintain the stability and reliability of the system, and protects the key equipment from being damaged.

[0061] In the present application, SOC balancing control is only performed for charging and discharging in grid-connected state, and not for charging and discharging in off-grid state, for the following reasons:

[0062] In the off-grid discharging state, if SOC balancing is achieved by limiting the discharge current size of the high-voltage battery, once the load exceeds the limit of the battery discharge, it will cause the DC bus voltage in the system to drop, and even cause the devices or machines in the system to fail to operate normally. This is because the discharge capacity of the battery is limited and cannot meet the needs of the system, resulting in the system failing to operate normally and triggering the machine protection mechanism. If the parallel current sharing strategy is changed to non-current sharing, some inverters will trigger overload protection first, and some inverters will need to bear more load, which may cause the entire system protection action. Non-current sharing will also introduce high-frequency circulating current, affecting power quality and system stability.

[0063] In the off-grid charging state, limiting the input of photovoltaic energy of the photovoltaic panel to achieve SOC balancing will cause the system to suffer a loss of income. Photovoltaic energy is the main charging source of the system, and limiting its input will reduce the income of the system and affect the economic efficiency of the system. The off-grid system should prioritize the use of photovoltaic energy to extend the power supply time, but limiting the input of photovoltaic energy to achieve SOC balancing will violate this principle and cause the system to fail to maximize the use of renewable energy.

[0064] In summary, the off-grid discharging SOC balancing and off-grid charging SOC balancing have the problem that implementing the SOC balancing strategy will cause serious challenges in system stability, economy and power quality, etc. These problems can cause abnormal system operation, reduced income, equipment damage and other serious consequences, so not opening the SOC balancing function in the off-grid state can avoid these problems and ensure the reliability and economy of the system.

[0065] In the embodiment, steps S101-S103 are performed according to a preset period, so as to realize real-time SOC balancing of the entire inverter parallel system, so as to ensure that the difference between the SOCs of the high-voltage batteries is as small as possible at any time, avoid the problem of overloading of part of the inverters due to unbalanced SOC, and improve the stability and reliability of the entire inverter parallel system.

[0066] As can be seen from the above description, in the embodiment, the average SOC is calculated according to the actual SOC of each battery module, the difference between the actual SOC and the average SOC can be calculated by each inverter, and the current correction value is obtained based on the difference. According to the charging and discharging state of the inverter parallel system and the battery current threshold of the high-voltage battery, the current correction value is used to adjust the battery current threshold to obtain the final current threshold. The current can be adjusted in real time according to the actual situation, which helps to control the charging speed of each high-voltage battery, improve the balance of the SOC of the inverter parallel system, avoid overloading of part of the inverters, reduce the risk of failure, and thus enhance the stability and reliability of the inverter parallel system.

[0067] Please refer to FIG. 2 and FIG. 3, FIG. 3 is a flowchart of another embodiment of the battery SOC balancing control method provided by the present application. The battery SOC balancing control method provided by the present application further comprises the following steps:

[0068] S201: Obtain the photovoltaic charging power of the photovoltaic panel connected to itself, obtain the current charging power according to the final current threshold, and obtain the excess charging amount based on the photovoltaic charging power and the current charging power.

[0069] In a specific implementation scenario, when the inverter parallel system is in a grid-connected charging state, after the final current threshold is obtained, since the final current threshold may limit the charging power, for example, when the actual SOC of the battery module is higher than the average SOC, it is necessary to limit the current size of the charging to reduce the SOC growth rate of the high-voltage battery, and the charging power of the high-voltage battery at this time is low. At this time, the electric energy collected by the photovoltaic panel of the same battery module as the high-voltage battery from the light energy exceeds the current demand of the high-voltage battery, and an electric energy surplus may occur.

[0070] To make full use of these excess electrical energy, the current charging power of the high-voltage battery can be obtained based on the photovoltaic charging power of the photovoltaic panel and the final current threshold currently obtained. If the current charging power is lower than the photovoltaic charging power, it means that the electrical energy provided by the photovoltaic panel is excessive. Based on the photovoltaic charging power and the excess charging power obtained when the charging power exceeds the charging power, the excess charging amount can be obtained according to the excess charging power.

[0071] S202: Transmit the excess charging amount to the micro-grid of the inverter parallel system, so that other inverters can obtain at least part of the excess charging amount from the micro-grid to charge the high-voltage battery corresponding to the other inverters.

[0072] In a specific implementation scenario, the excess charging amount is transmitted to the micro-grid of the inverter parallel system, so that other inverters can obtain the excess charging amount from the micro-grid to charge the high-voltage battery corresponding to the other inverters. This mechanism of sharing charging amount helps to optimize the charging state of each high-voltage battery in the inverter parallel system and improve the overall efficiency and performance of the system.

[0073] The micro-grid refers to the local power network formed before the output side of multiple machines of the entire inverter parallel system is connected to the actual power grid, that is, the inverter parallel system in the embodiment realizes overall anti-backflow, and the parallel power network before the total CT (Current transformer, current transformer) sampling port. In this micro-grid, multiple inverters are operated in parallel to form a local power network. This micro-grid can operate independently or be connected to the actual power grid. In this micro-grid, inverters can share energy, operate cooperatively, and ensure system stability and safety through designed control strategies. The output currents of all inverters are sampled and then monitored and controlled through CT. Through monitoring and analysis of these current data, the inverter parallel system can realize overall anti-backflow function to ensure that the current output by the inverter parallel system to the power grid meets the requirements and avoid the occurrence of backflow phenomenon.

[0074] For example, when the actual SOC of the battery module is lower than the average SOC, the charging current needs to be increased to speed up the SOC growth rate of the high-voltage battery, and the charging power required by the high-voltage battery is higher at this time. At this time, the electrical energy collected by the photovoltaic panel of the same battery module as the high-voltage battery cannot meet the current demand of the high-voltage battery, which not only affects the charging efficiency of the battery module, but also affects the SOC balancing effect of the entire inverter parallel system. At this time, the inverter of the battery module obtains at least part of the excess electrical energy through the micro-grid to meet the charging demand of the current battery module, which not only better maintains the SOC balance of the entire inverter parallel system, but also fully utilizes the electrical energy provided by each photovoltaic panel, thereby improving the resource utilization rate.

[0075] Please refer to FIG. 4 and FIG. 2, FIG. 4 is a flow chart of another embodiment of the battery SOC equalization control method provided by the present application. The battery SOC equalization control method provided by the present application further comprises the following steps:

[0076] S301: When the current charging power is higher than the photovoltaic charging power, at least part of the excess charging power is obtained from the micro-grid according to the difference between the photovoltaic charging power and the current charging power, and the at least part of the excess charging power is provided to the corresponding high-voltage battery.

[0077] In a specific implementation scenario, when the current charging power of a battery module is higher than the photovoltaic charging power, it indicates that the current power provided by the photovoltaic panel cannot meet the charging demand of the high-voltage battery. Therefore, the actual charging power required is obtained according to the difference between the photovoltaic charging power and the current charging power, at least part of the excess charging power is obtained from the micro-grid as the actual charging power, and the actual charging power is charged into the high-voltage battery. In this way, the charging demand of the current battery module can be met, and the excess power of other battery modules can be reasonably used.

[0078] The current inverter parallel system opens the anti-backflow function, and needs to adjust the maximum average grid-connected current of all battery modules according to the current size of the inverter parallel system feeding into the grid. The purpose of this is that in the case that the excess energy generated by the photovoltaic panel is used to charge other battery modules, the inverter parallel system can still meet the anti-backflow requirement.

[0079] In this embodiment, the power output by the inverter feeding into the grid is defined as backflow, and the anti-backflow function is to prevent the excess power of the inverter system from feeding into the grid and affecting the quality of the grid. When the power output by the photovoltaic panel exceeds the demand of the corresponding high-voltage battery, it can be fed into the micro-grid of the inverter parallel system, but the interface of the entire inverter parallel system connected with the grid still meets the system-level anti-backflow requirement. That is, if there is still excess power after the internal coordination of the entire inverter parallel system (for example, all high-voltage batteries are fully charged, but there is still excess power provided by the photovoltaic panel), it needs to be further limited according to the anti-backflow requirement.

[0080] In order to improve the safety of the inverter parallel system, the inverter parallel system adjusts the average discharge current limit value of all machines. In this implementation scenario, the total discharge current limit value is obtained, and the average discharge current limit value is obtained according to the total discharge current limit value; the inverter needs to obtain at least part of the excess charging power from the micro-grid with a current lower than the average discharge current limit value.

[0081] In this way, the inverter parallel system can effectively utilize the excess energy generated by the photovoltaic panels, while ensuring that the system operation meets the requirements of anti-backflow, thereby improving the energy utilization efficiency and stability of the inverter parallel system.

[0082] As can be seen from the above description, in the embodiment, when the electric energy generated by the photovoltaic panels exceeds the charging demand of the corresponding high-voltage battery, the excess electric energy is provided to the micro-grid of the inverter parallel system, so that the battery module whose electric energy generated by the photovoltaic panels cannot meet the charging demand of the high-voltage battery can obtain the excess electric energy from the micro-grid for charging the high-voltage battery. The SOC of the entire inverter parallel system can be better maintained, and the electric energy provided by each photovoltaic panel can be fully utilized, thereby improving the resource utilization rate.

[0083] Referring to FIG. 5, FIG. 5 is a structural schematic diagram of an embodiment of the energy supply device provided by the present application. The energy supply device 20 comprises a processor 21 and a memory 22. The processor 21 is coupled to the memory 22. The memory 22 stores a computer program, and the processor 21 executes the computer program when working to realize the method as described above. The detailed steps can be referred to the above description, and will not be described here again.

[0084] Referring to FIG. 6, FIG. 6 is a structural schematic diagram of an embodiment of the computer readable storage medium provided by the present application. The computer readable storage medium 30 stores at least one computer program 31, and the computer program 31 is used to be executed by the processor to realize the method as described above. The detailed steps can be referred to the above description, and will not be described here again. In an embodiment, the computer readable storage medium 30 can be a storage chip in a terminal, a hard disk, or a mobile hard disk or an optical disc, or other readable and writable storage tools, and can also be a server, etc.

[0085] The storage medium can be implemented by any type of volatile or nonvolatile storage devices, or a combination thereof. Among them, the nonvolatile memory can be a Read Only Memory (ROM), a Programmable Read-Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a Ferromagnetic Random Access Memory (FRAM), a Flash Memory, a magnetic surface memory, an optical disc, or a Compact Disc Read-Only Memory (CD-ROM). The magnetic surface memory can be a disk memory or a tape memory. The volatile memory can be a Random Access Memory (RAM) used as an external cache. By way of example and not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Synchronous Static Random Access Memory (SSRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDR SDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), Sync Link Dynamic Random Access Memory (SLDRAM), Direct Rambus Random Access Memory (DRRAM). The storage medium described in the embodiments of the present application is intended to include but not limited to these and any other suitable types of memory.

[0086] In several embodiments provided by the present application, it should be understood that the disclosed system and method can be implemented in other manners. The described device embodiments are merely illustrative, for example, the division of the units is only a logical function division, and there can be another division manner in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling, or direct coupling or communication connection between the components can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or in other forms.

[0087] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, can be located in one place, or can be distributed on a plurality of network units; some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0088] In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in the form of hardware, or in the form of hardware plus software functional units.

[0089] Those skilled in the art can understand that all or part of the steps of the above method embodiments can be completed by relevant hardware instructed by programs, and the foregoing programs can be stored in a computer readable storage medium, and when the programs are executed, the steps of the above method embodiments are executed; and the foregoing storage medium includes mobile storage devices, read-only memories (ROMs), random access memories (RAMs), magnetic disks or optical disks, and various media capable of storing program codes.

[0090] Alternatively, the above-mentioned integrated unit of the present application, if realized in the form of a software function module and sold or used as an independent product, can also be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the methods described in the embodiments of the present application. The aforementioned storage medium includes: mobile storage devices, ROM, RAM, magnetic disks or optical disks, and various other media that can store program codes.

[0091] The methods disclosed in the several method embodiments of the present application can be combined arbitrarily without conflict to obtain new method embodiments.

[0092] The features disclosed in the several product embodiments of the present application can be combined arbitrarily without conflict to obtain new product embodiments.

[0093] The features disclosed in the several method or device embodiments of the present application can be combined arbitrarily without conflict to obtain new method or device embodiments.

[0094] The above is a further detailed description of the present application in combination with specific preferred embodiments, and the specific implementation of the present application cannot be limited to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of equivalent substitutions or obvious modifications can be made, and the performance or use is the same, which should be regarded as belonging to the protection scope of the present application.

Claims

1. A battery SOC equalization control method, characterized by, The application is applied to an inverter parallel system, the inverter parallel system includes at least two groups of battery modules, each of the battery modules includes an inverter, and a photovoltaic panel and a high-voltage battery connected with the inverter; the inverters of two adjacent groups of the battery modules are connected with each other. The battery SOC equalization control method includes the following steps: According to a preset equalization period, a current inverter obtains a battery actual SOC of a high-voltage battery connected with the inverter, and provides the battery actual SOC to a preset host to obtain an average SOC provided by the preset host according to the battery actual SOC; An SOC difference value between the battery actual SOC and the average SOC is obtained, and a current correction value is obtained based on the SOC difference value; A charge-discharge state of the inverter parallel system and a battery current threshold of the high-voltage battery are obtained, the battery current threshold is corrected based on the charge-discharge state by using the current correction value, and a final current threshold is obtained.

2. The battery SOC equalization control method according to claim 1, characterized by, The step of correcting the battery current threshold based on the charge-discharge state by using the current correction value includes: If the current is in a grid-connected charging state, the final current threshold is obtained by subtracting the current correction value from the battery current threshold; If the current is in a grid-connected discharging state, the final current threshold is obtained by adding the current correction value to the battery current threshold.

3. The battery SOC equalization control method according to claim 2, characterized by, After the step of obtaining the final current threshold, the following steps are included: An inverter current threshold of the current inverter is obtained, the minimum one of the inverter current threshold and the battery current threshold is taken as a target threshold, and the final current threshold is limited by using the target threshold, so that the final current threshold is between 0 and the target threshold.

4. The battery SOC equalization control method according to claim 2, characterized by, If the current is in the grid-connected charging state, after the step of obtaining the final current threshold, the following steps are included: A photovoltaic charging power of the photovoltaic panel connected with the current inverter is obtained, a current charging power is obtained according to the final current threshold, an excess charging amount is obtained based on the photovoltaic charging power and the current charging power; the excess charging amount is transmitted to a micro-grid of the inverter parallel system, so that other inverters can obtain at least part of the excess charging amount from the micro-grid to charge the high-voltage battery corresponding to the other inverters; or After the step of obtaining the final current threshold, the following steps are included: When the current charging power is higher than the photovoltaic charging power, at least part of the excess charging amount is obtained from the micro-grid according to the difference between the photovoltaic charging power and the current charging power, and at least part of the excess charging amount is provided to the corresponding high-voltage battery. The step of obtaining the excess charging amount from the micro-grid includes:

5. The battery SOC equalization control method according to claim 4, characterized by, An average discharging current limiting value is obtained according to a total discharging current limiting value; At least part of the excess charging amount is obtained from the micro-grid at a current lower than the average discharging current limiting value. The step of obtaining the current correction value based on the SOC difference value includes:

6. The battery SOC equalization control method according to any one of claims 1 to 5, characterized by, A preset proportion coefficient is obtained, and the proportion coefficient is multiplied by the SOC difference value to obtain the current correction value. ​ 7. The battery SOC equalization control method according to any one of claims 1 to 5, characterized by, The step of providing the preset host with the actual SOC of the battery comprises: One inverter from at least one set of battery modules is selected as the preset host.

8. An inverter paralleling system, characterized by comprising: The inverter parallel system comprises at least one set of battery modules, each of which comprises an inverter, a photovoltaic panel and a high-voltage battery connected to the inverter; the inverters of two adjacent sets of battery modules are connected to each other. The inverter is used to implement the battery SOC equalization control method of any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, A computer program is stored, and when executed by a processor, the computer program causes the processor to execute the steps of the method of any one of claims 1-7.

10. An energy supply device, characterized by A memory and a processor are included, and the memory stores a computer program, which, when executed by the processor, causes the processor to execute the steps of the method of any one of claims 1-7.

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