Control method, device, system and equipment for multi-battery-module parallel energy storage system

Abstract

The invention discloses a control method, device, system and equipment for a multi-battery-module parallel energy storage system. Comprising the following steps: controlling each battery module to perform translation correction in different directions on the basis of an initial droop curve in combination with state parameters of each battery module in a grid-connected and off-grid state to obtain a corrected droop curve; and controlling the power redistribution and equalization of each battery module according to the corrected droop curve corresponding to each battery module and the output total power limit. According to the invention, bidirectional equalization of the multiple battery modules is realized while power distribution is realized, so that the operation stability of the energy storage system is improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage system technology, and in particular to control methods, devices, systems and equipment for multi-battery module parallel energy storage systems. Background Technology

[0002] With the increasing awareness of environmental protection, new energy sources such as wind power and photovoltaics are being used more and more. Correspondingly, energy storage systems, as energy storage devices, provide important support for the stable development of the new energy field. In order to adapt to the increase in the capacity of energy storage systems, existing technologies provide an energy storage system with multiple battery modules connected in parallel.

[0003] In a multi-module parallel energy storage system, when the state of charge (SOC) of a battery module is low, the maximum discharge current voltage (MDCV) limits the module's discharge capacity. Therefore, the energy storage system exhibits a "weakest link" effect: if the battery module with the lowest load-carrying capacity is overloaded, it will exit the system, and the load will be distributed among the remaining modules, thus impacting the overall stability of the system. Summary of the Invention

[0004] This invention provides a control method, device, system, and equipment for a multi-battery module parallel energy storage system, which can achieve bidirectional balancing of multiple battery modules while distributing power, thereby improving the stability of the energy storage system operation.

[0005] According to one aspect of the present invention, a control method for a multi-battery module parallel energy storage system is provided, comprising:

[0006] In both on-grid and off-grid states, based on the state parameters of each battery module, each battery module is controlled to undergo translational correction in different directions on the basis of the initial droop curve, thus obtaining a corrected droop curve.

[0007] Based on the corrected droop curve and total output power limit corresponding to each battery module, the power redistribution and balancing of each battery module are controlled.

[0008] Optionally, the step of combining the state parameters of each battery module to control each battery module to perform translational correction in different directions based on the initial sag curve, thereby obtaining a corrected sag curve, specifically includes:

[0009] Based on the state parameters of each battery module, determine the target value for balancing the battery state parameters;

[0010] Based on the state parameters of the battery module itself and the balanced target value of the battery state parameters, determine the first shift correction amount of the current reference voltage value of the battery module;

[0011] Based on the reference voltage value and the first translation correction amount, the initial droop curve is translated and corrected to obtain the current corrected droop curve of the battery module.

[0012] Optionally, after determining the first shift correction amount of the current reference voltage value of the battery module based on the battery module's own state parameters and the balanced target value of the battery state parameters, the method further includes:

[0013] The first translation correction amount is subjected to amplitude limiting control to obtain the first translation correction amount after amplitude limiting; and the initial droop curve is translated and corrected using the first translation correction amount after amplitude limiting.

[0014] Optionally, before performing translation correction on the initial droop curve based on the reference voltage value and the first translation correction amount to obtain the current corrected droop curve of the battery module, the method further includes:

[0015] Based on the bus voltage and the bus voltage reference value, a second translation correction amount for the reference voltage value is determined; and the initial droop curve is translated and corrected using the first translation correction amount and the second translation correction amount.

[0016] Optionally, after determining the second shift correction amount of the reference voltage value based on the bus voltage and the bus voltage reference value, the method further includes:

[0017] The second translation correction amount is subjected to amplitude limiting control to obtain the amplitude-limited second translation correction amount; and the amplitude-limited second translation correction amount is used to perform translation correction on the initial droop curve.

[0018] Optionally, the step of applying the first translation correction amount and the second translation correction amount to the initial sag curve for translation correction specifically includes:

[0019] The final voltage reference value offset is obtained based on the reference voltage value, the first translation correction amount, and the second translation correction amount.

[0020] The initial droop curve is shifted and corrected based on the offset of the final voltage reference value.

[0021] Optionally, determining the first shift correction amount of the current reference voltage value of the battery module based on the battery module's own state parameters and the balanced target value of the battery state parameters includes:

[0022] The equilibrium target difference is obtained based on the state parameters of the battery module itself and the equilibrium target value of the battery state parameters.

[0023] Based on the balance target difference and the first translation correction curve, the first translation correction amount of the current reference voltage value of the battery module is determined; wherein, the first translation correction amount curve represents the correspondence between the balance target difference and the first translation correction amount;

[0024] And / or, the determination of the second shift correction amount of the reference voltage value based on the bus voltage and the bus voltage reference value includes:

[0025] Determine the target voltage difference based on the bus voltage and the bus voltage reference value;

[0026] Based on the voltage target difference and the second translation correction curve, the second translation correction amount of the reference voltage value is determined; wherein, the second translation correction curve characterizes the correspondence between the voltage target difference and the second translation correction amount.

[0027] Optionally, the method for obtaining the reference voltage value includes:

[0028] The reference voltage value is determined based on the initial droop curve and the total output power of each battery module.

[0029] Optionally, controlling the power redistribution and balancing of each battery module based on the corrected droop curve and total output power limit corresponding to each battery module includes:

[0030] Based on the corrected droop curve and total output power limit corresponding to each battery module, the target reference voltage value and the corresponding power of each battery module are determined; wherein the corresponding power of each battery module can meet the power distribution and balancing requirements.

[0031] Optionally, controlling the power redistribution and balancing of each battery module based on the corrected droop curve and total output power limit corresponding to each battery module specifically includes:

[0032] Based on the corrected droop curve and total output power limit corresponding to each battery module, the final reference voltage value of each battery module is determined;

[0033] Based on the final value of the reference voltage and the current output voltage of each battery module, the battery optimizer of the corresponding battery module is controlled.

[0034] According to another aspect of the present invention, a control device for a multi-battery module parallel energy storage system is provided, comprising:

[0035] The droop curve correction module is used to control each battery module to perform translation correction in different directions based on the initial droop curve, in the parallel and off-grid states, combined with the state parameters of each battery module itself, to obtain the corrected droop curve.

[0036] The power distribution and equalization control module is used to control the power redistribution and equalization of each battery module according to the corrected droop curve and the total output power limit corresponding to each battery module.

[0037] According to another aspect of the present invention, a multi-battery module parallel energy storage system is provided, comprising: a plurality of battery modules, photovoltaic modules and energy storage converters connected in parallel, wherein the energy storage converters perform the control method of the multi-battery module parallel energy storage system according to any embodiment of the present invention.

[0038] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0039] At least one processor; and

[0040] A memory communicatively connected to the at least one processor; wherein,

[0041] The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to execute the control method of the multi-battery module parallel energy storage system according to any embodiment of the present invention.

[0042] According to another aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to execute and implement the control method of the multi-battery module parallel energy storage system according to any embodiment of the present invention.

[0043] The technical solution provided in this invention, by combining the state parameters of each battery module, shifts and corrects the initial droop curve of the battery in different directions to obtain a corrected droop curve. Based on the corrected droop curve of each battery module and the total output power limit, the power redistribution and balancing of each battery module are controlled. During this process, the total output power of each battery module remains constant. The input or output power of each battery module is adjusted according to its corrected droop curve, thereby adjusting the state parameters of each battery module. This setup allows each battery module to adjust its allocated power according to its own situation, enabling power distribution in a multi-battery module parallel energy storage system. It also achieves bidirectional adjustment and balancing of the State of Charge (SOC), improving the cycle life of the cells and enhancing the stability of the energy storage system.

[0044] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of a multi-battery module parallel energy storage system provided in an embodiment of the present invention;

[0047] Figure 2 A flowchart of a control method for a multi-battery module parallel energy storage system provided in an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of a modified sag curve provided in an embodiment of the present invention;

[0049] Figure 4 A flowchart illustrating another control method for a multi-battery module parallel energy storage system provided in an embodiment of the present invention;

[0050] Figure 5 A schematic diagram of a first translation correction curve provided in an embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram of another modified sag curve provided in an embodiment of the present invention;

[0052] Figure 7 A flowchart illustrating another control method for a multi-battery module parallel energy storage system provided in an embodiment of the present invention;

[0053] Figure 8 A schematic diagram of a second translation correction curve provided in an embodiment of the present invention;

[0054] Figure 9 This is a schematic diagram of another modified sag curve provided in an embodiment of the present invention;

[0055] Figure 10 A flowchart illustrating another control method for a multi-battery module parallel energy storage system provided in an embodiment of the present invention;

[0056] Figure 11 This is a schematic diagram of another modified sag curve provided in an embodiment of the present invention;

[0057] Figure 12 This is a schematic diagram of the structure of a control device for a multi-battery module parallel energy storage system provided in an embodiment of the present invention;

[0058] Figure 13 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0059] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0060] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0061] To facilitate understanding of the control method for the multi-battery module parallel energy storage system provided in the embodiments of the present invention, the multi-battery module parallel energy storage system provided in the embodiments of the present invention will first be described. Figure 1 This is a schematic diagram of a multi-battery module parallel energy storage system provided in an embodiment of the present invention. Figure 1As shown, exemplarily, this multi-battery module parallel energy storage system is applied to a photovoltaic system. The multi-battery module parallel energy storage system includes n battery modules 110, a power conversion system (PCS) 120, photovoltaic modules 130, a power grid 140, and a load 150. The n battery modules 110 are designated as first battery module 1101, ..., and nth battery module 110n. Each battery module 110 includes multiple battery cells and a battery optimizer. The battery optimizer, i.e., a DC / DC converter, can regulate the voltage of each battery module 110 to a consistent level, ensuring that all battery modules 110 can be connected in parallel with the same voltage. The DC / DC converter can also increase or decrease the voltage of the battery modules 110 to adapt to the voltage level required by the system. The output voltage of the multiple battery modules 110 is V0. The PCS 120 includes a DC bus voltage V0. BUS Boost converters, bidirectional DC-DC converters (BDC), and inverters (INV).

[0062] PV130 absorbs solar energy, converts it into direct current, and then exchanges energy and converts the voltage with battery module 110 via PCS120 to supply power to grid 140 and / or load 150. For example, if the electrical energy generated by PV130 is sufficient for grid 140 and / or load 150, excess electrical energy is stored in n battery modules 110 for later use. If the electrical energy generated by PV130 is insufficient for grid 140 and / or load 150, power is supplied to grid 140 and / or load 150 through n battery modules 110 to ensure the overall system's power supply reliability.

[0063] Figure 2 This is a flowchart illustrating a control method for a multi-battery module parallel energy storage system according to an embodiment of the present invention. This embodiment is applicable to the equalization control of a multi-battery module parallel energy storage system in both grid-connected and off-grid (grid-connected or off-grid) states. The method can be executed by a control device for the multi-battery module parallel energy storage system. This control device can be implemented in hardware and / or software and can be configured within the multi-battery module parallel energy storage system, specifically within the battery optimizer of each battery module. Figure 2 As shown, the method includes the following steps:

[0064] S210. In both parallel and off-grid states, based on the state parameters of each battery module, each battery module is controlled to undergo translational correction in different directions on the basis of the initial droop curve, thereby obtaining the corrected droop curve.

[0065] The terms "grid-connected" and "off-grid" refer to whether the multi-battery module parallel energy storage system is in a grid-connected or off-grid state. In the grid-connected state, the system is connected to the power grid and can supply power to or obtain power from the grid; in the off-grid state, the system is disconnected from the power grid.

[0066] State parameters refer to various indicators used to describe the current state of a battery module. These indicators can reflect the health status, performance, and safety of the battery module. For example, the state parameters of a battery module include at least one of the following: current charge level, output voltage, output current, and state of charge (SOC), preferably SOC.

[0067] The initial droop curve refers to the relationship curve between the output power and output voltage of the battery module, issued by the upper-level control system. In this embodiment of the invention, the droop curve of each battery module is adjusted based on this initial droop curve. For example, Figure 3 This is a schematic diagram illustrating an initial sag curve and a corrected sag curve, provided as an embodiment of the present invention. Figure 3 As shown, the horizontal axis (power axis) of the initial droop curve Droop_Initial represents the output power P of the battery module, and the vertical axis (voltage axis) represents the output voltage V of the battery module. The voltage corresponding to the battery module's output power of P1 is the reference voltage value V. oref The maximum output power is P. n The corresponding voltage is V omax The lower limit of output power is -P. n The corresponding voltage is V omin .

[0068] A corrected droop curve refers to the curve obtained after correcting the initial droop curve. Specifically, it can be achieved by shifting the initial droop curve along the voltage axis. See also the examples below. Figure 3 The horizontal axis (power axis) represents the output power P of the battery module, and the vertical axis (voltage axis) represents the output voltage V of the battery module. The black solid line Droop_Initial represents the initial droop curve, while the orange solid line Droop_SOC1 and the red solid line Droop_SOC2 both represent corrected droop curves. For example, the orange solid line Droop_SOC1 is the corrected droop curve corresponding to the first battery module, and its corresponding state parameter is SOC1; the red solid line Droop_SOC2 is the corrected droop curve corresponding to the second battery module, and its corresponding state parameter is SOC2; SOC1 > SOC2.

[0069] like Figure 3As shown, the corrected droop curves Droop_SOC1 and Droop_SOC2 of the first battery module are shifted in different directions. For example, for the first battery module, shifting the initial droop curve downwards yields the corrected droop curve Droop_SOC1, increasing its output power while maintaining the same output voltage. For the second battery module, shifting the initial droop curve upwards yields the corrected droop curve Droop_SOC2, decreasing its output power while maintaining the same output voltage.

[0070] As the foregoing analysis shows, the output voltage of each battery module should be the same. Figure 3 It can be seen that, at the same output voltage V oref_fin Due to the different correction droop curves, the power of the first and second battery modules differs. Specifically, the first battery module has a higher SOC1 and a positive power P2, indicating it is in a discharging state; the second battery module has a lower SOC2 and a negative power P3, indicating it is in a charging state. During this process, the SOC1 of the first battery module decreases, while the SOC2 of the second battery module increases. Therefore, by adjusting the power of each battery module, this embodiment of the invention can optimize its state parameters, achieving bidirectional balance between the battery modules.

[0071] S220: Based on the corrected droop curve and total output power limit of each battery module, control the power redistribution and balancing of each battery module.

[0072] The corrected droop curve is obtained in step S210 above. The total output power limit refers to the total output power required by the system for the multi-battery module parallel energy storage system. This total output power limit can be jointly determined by the load, other new energy systems, and the power grid. See [link to relevant documentation] Figure 3 For example, when all battery modules use the initial droop curve Droop_Initial, the output power of each battery module is P1, and their sum is the total output power. Power redistribution refers to adjusting the output power of each battery cell according to the real-time status and load demand of the battery modules, meaning that the power of each battery module is different. Battery module balancing refers to ensuring that the state parameters of each battery module remain consistent during charging and discharging to avoid large differences between batteries, thereby preventing the battery module with the lowest load capacity from exiting the energy storage system due to overload.

[0073] Optionally, S220 specifically includes: determining the target reference voltage value and the corresponding power of each battery module based on the corrected droop curve and the total output power limit corresponding to each battery module; wherein the corresponding power of each battery module can meet the power distribution and balancing requirements.

[0074] For example, see Figure 3 By shifting the output voltage up and down along the vertical axis, different power combinations can be determined on the corrected sag curve. These power combinations need to satisfy the total output power. In this embodiment, when the target reference voltage is determined to be the output voltage V, oref_fin At that time, the power corresponding to the first battery module is P2; the power corresponding to the second battery module is P3.

[0075] The technical solution provided in this invention, by combining the state parameters of each battery module, shifts and corrects the initial droop curve of the battery in different directions to obtain a corrected droop curve. Based on the corrected droop curve of each battery module and the total output power limit, the power redistribution and balancing of each battery module are controlled. During this process, the total output power of each battery module remains constant. The input or output power of each battery module is adjusted according to its corrected droop curve, thereby adjusting the state parameters of each battery module. This setup allows each battery module to adjust its allocated power according to its own situation, enabling power distribution in a multi-battery module parallel energy storage system. It also achieves bidirectional adjustment and balancing of the State of Charge (SOC), improving the cycle life of the cells and enhancing the stability of the energy storage system.

[0076] Furthermore, in this embodiment of the invention, the adjustment of the initial droop curve targets the relationship between the power and voltage of the battery module. Those skilled in the art will understand that the adjustment of the droop curve can also include frequency adjustment. However, in grid-connected mode, the system frequency should remain constant. This embodiment of the invention uses a droop curve with a linear relationship between power and output voltage, which is applicable to both grid-connected and off-grid modes, has a wider range of applications, and helps to make the system operation more stable. Furthermore, the adjustment of the output voltage will affect the power of the battery module, and the voltage bus of the battery module will also be output after passing through the energy storage converter. This voltage can be adjusted through the energy storage converter, thus not affecting the load or the grid voltage.

[0077] Figure 4 A flowchart illustrating another control method for a multi-battery module parallel energy storage system provided in an embodiment of the present invention. Figure 4 As shown, based on the above embodiments, optionally, in S210, under the parallel-to-off-grid state, by combining the state parameters of each battery module, each battery module is controlled to perform translational correction in different directions based on the initial droop curve to obtain a corrected droop curve. Specifically, this may include the following steps:

[0078] S211. Determine the target value for balancing the battery state parameters based on the state parameters of each battery module.

[0079] Taking the State of Charge (SOC) as an example, the balancing target value can be interpreted as the simultaneous SOC that each battery module can achieve. Setting the balancing target value helps maintain consistency among the battery modules during charging and discharging. It is understood that the state parameters change in real time during the operation of the energy storage system; therefore, the balancing target value needs to be dynamically adjusted according to the actual situation at different times. For example, the balancing target value should be dynamically adjusted between the minimum and maximum SOC of the battery modules.

[0080] S212. Based on the state parameters of the battery module itself and the balanced target value of the battery state parameters, determine the first shift correction amount of the reference voltage value of the current battery module.

[0081] For example, refer to Figure 3 The reference voltage value Voref is determined by the total power P required to be output by each battery module. o The decision is made, and P1 = P O / n, where n is the number of battery modules. If the power P1 remains constant, the output voltage of the corrected droop curve Droop_SOC1 corresponding to the first battery module changes, and this change is the first shift correction amount. The magnitude of this change can be determined by the first shift correction amount curve, which can be adjusted and determined as needed in practical applications.

[0082] Optionally, the first translation correction amount can be determined by constructing a first translation correction amount curve, which represents the correspondence between the equilibrium target difference and the first translation correction amount. The equilibrium target difference is obtained based on the battery module's own state parameters and the equilibrium target values ​​of the battery state parameters; the first translation correction amount for the current battery module's reference voltage value is determined based on the equilibrium target difference and the first translation correction amount curve.

[0083] For example, Figure 5 This is a schematic diagram of a first translation correction curve provided in an embodiment of the present invention. Figure 5 As shown, its horizontal axis is E. rr_soc The vertical axis represents the difference between the current state of charge (SOC) of the battery module and the target equilibrium value; the vertical axis represents the first translation correction V1 of the drooping curve. The first translation correction of the drooping curve can be determined based on the SOC equilibrium target difference. For example, when the equilibrium target difference between the current battery module's SOC and the target equilibrium value is Δsoc1, the corresponding first translation correction is V1. offset1 .

[0084] Figure 6 This is a schematic diagram illustrating another modified sag curve provided in an embodiment of the present invention. (In conjunction with...) Figures 5-6Obtain the total output power P of each battery module. o The power allocated to each battery module is P1 = P O / n, where n is the number of battery modules. The initial droop curve of the battery module is Droop_Initial, based on the power P of the battery module. O The reference voltage V can be determined by using / n and the initial droop curve Droop_Initial. oref Based on the SOC value of the battery module and the balanced target SOC value... target The equilibrium target difference Δsoc1 can be obtained. Based on the equilibrium target difference Δsoc1 and Figure 5 The curve shown represents the first translation correction, from which the first translation correction V is obtained. offset1 .

[0085] S213. Based on the reference voltage value and the first translation correction amount, the initial droop curve is translated and corrected to obtain the corrected droop curve of the current battery module.

[0086] See also Figure 6 For example, based on the initial droop curve Droop_Initial, a first translation correction amount V is shifted downwards. offset1 The corrected droop curve Droop_Modified1 of the battery module is obtained, which is the corrected droop curve Droop_SOC1.

[0087] It should be noted that this embodiment uses a downward-shifted corrected droop curve as an example for illustration, and is not intended to limit the invention. In practical applications, there are a large number of battery modules in the energy storage system, and there are both downward-shifted and upward-shifted corrected droop curves. Therefore, the embodiment of the present invention can achieve both high SOC to low SOC and low SOC to high SOC.

[0088] Through S211-S213, the corrected droop curve of the current battery module can be obtained. The embodiments of the present invention enable each battery module to adjust the allocated power according to its own situation, realize the power distribution of the multi-battery module parallel energy storage system, and realize bidirectional adjustment and balancing of SOC, improve the cycle life of the cells, and enhance the stability of the energy storage system operation.

[0089] See also Figure 6 Based on the above embodiments, optionally, after determining the first translation correction amount of the reference voltage of the current battery module according to the state parameters of the battery module itself and the equalization target value of the battery state parameters, the method further includes: limiting the first translation correction amount to obtain the limited first translation correction amount; and using the limited first translation correction amount to perform translation correction on the initial droop curve.

[0090] In this embodiment of the invention, amplitude limiting control can be interpreted as applying upper and lower limits to a certain parameter (in this example, the first translation correction amount) to ensure that the parameter is corrected within a certain reasonable range. Amplitude limiting control of the first translation correction amount can prevent unreasonable translation correction output due to excessive correction amount.

[0091] like Figure 5 As shown, in the first quadrant, the vertical axis of the inflection point of the first translation correction corresponds to the maximum offset V. offset1_UpLimit That is, the upper limit of the first translation correction is V. offset1_UpLimit At this point, the horizontal axis corresponds to the maximum SOC difference, Δsoc_max. In the third quadrant, the vertical axis at the inflection point of the first translation correction corresponds to the minimum offset, V. offset1_DownLimit That is, the lower limit of the first translation correction is V. offset1_DownLimit At this point, the horizontal axis corresponds to the largest negative SOC difference value -Δsoc_max.

[0092] Based on the above embodiments, optionally, before S213, when the initial droop curve is shifted and corrected according to the reference voltage reference value and the first shift correction amount to obtain the corrected droop curve of the current battery module, the method further includes: determining a second shift correction amount of the reference voltage reference value according to the bus voltage and the bus voltage reference value.

[0093] Figure 7 A flowchart of another control method for a multi-battery module parallel energy storage system provided in an embodiment of the present invention is shown below. Figure 7 Specifically, in S210, under both parallel and off-grid conditions, based on the state parameters of each battery module, each battery module is controlled to undergo translational correction in different directions according to the initial droop curve, resulting in a corrected droop curve. This can include the following steps:

[0094] S211. Determine the target value for balancing the battery state parameters based on the state parameters of each battery module.

[0095] S212. Based on the state parameters of the battery module itself and the balanced target value of the battery state parameters, determine the first shift correction amount of the reference voltage value of the current battery module.

[0096] S214. Determine the second shift correction amount of the reference voltage value based on the bus voltage and the bus voltage reference value.

[0097] For example, such as Figure 1As shown, the bus voltage can be the DC bus voltage VBUS of the inverter (INV) in the energy storage converter 120. In some cases, the energy storage system also includes new energy power generation systems such as photovoltaic (PV) modules. Due to the instability of their power generation, the bus voltage may spike. This embodiment of the invention further adjusts the droop curve based on the real-time status of the bus voltage, thereby further improving the stability of the energy storage system.

[0098] Optionally, the second translation correction amount can be determined by constructing a second translation correction amount curve, which characterizes the correspondence between the voltage target difference and the second translation correction amount. The voltage target difference is determined based on the bus voltage and the bus voltage reference value; the second translation correction amount for the reference voltage value is determined based on the voltage target difference and the second translation correction amount curve.

[0099] For example, Figure 8 This is a schematic diagram of a second translation correction curve provided in an embodiment of the present invention. Figure 8 As shown, its horizontal axis is Err_V dif The vertical axis represents the target voltage difference between the current bus voltage and the bus voltage reference value; the vertical axis represents the second translation correction amount V2 of the droop curve. The second translation correction amount of the droop curve can be determined based on the target voltage difference. For example, if the target voltage difference between the current bus voltage and the bus voltage reference value is ΔV1, the corresponding second translation correction amount of the droop curve is V2. offset2 .

[0100] Figure 9 This is a schematic diagram illustrating another modified sag curve provided in an embodiment of the present invention. (In conjunction with...) Figures 8-9 Obtain the total output power P of each battery module. o The power allocated to each battery module is P1 = P O / n, where n is the number of battery modules. The initial droop curve of the battery module is Droop_Initial, based on the power P of the battery module. O The / n and initial droop curve Droop_Initial can determine the reference voltage V of the battery module. oref Based on the SOC value of the battery module and the balanced target SOC value... target The equilibrium target difference Δsoc1 can be obtained. Based on the equilibrium target difference Δsoc1 and Figure 5 The curve shown represents the first translation correction, from which the first translation correction V is obtained. offset1 And, based on the bus voltage value V of the battery module BUS Compared with the bus voltage reference value V BUSref The target voltage difference ΔV1 can be obtained, based on the target voltage difference ΔV1 and Figure 8The second translation correction curve shown yields the second translation correction V. offset2 .

[0101] S215. The initial droop curve is shifted and corrected according to the reference voltage value, the first shift correction amount, and the second shift correction amount to obtain the corrected droop curve of the current battery module.

[0102] See also Figure 9 For example, based on the initial droop curve Droop_Initial, a first translation correction amount V is shifted downwards. offset1 The intermediate corrected droop curve Droop_SOC of the battery module is obtained, and the second translation correction amount V is then shifted downwards. offset2 The corrected droop curve Droop_SOC2 of the battery module is obtained.

[0103] It should be noted that this embodiment uses an upwardly shifted corrected droop curve as an example for illustration, and is not intended to limit the invention. In practical applications, there are a large number of battery modules in the energy storage system, and there are both upwardly shifted corrected droop curves and downwardly shifted corrected droop curves. Therefore, the embodiment of the present invention can achieve both high SOC to low SOC and low SOC to high SOC.

[0104] The technical solution provided in this invention obtains a second shift correction amount by calculating the difference between the bus voltage and the bus voltage reference value. Based on this second shift correction amount, the charging strategy of the battery module can be adjusted to better receive the remaining energy on the bus. That is, the remaining energy of the PV module can be absorbed by the parallel-connected multiple battery modules, reducing the impact on the stability of the parallel energy storage system when the battery module with the lowest load capacity exits the system due to overload.

[0105] Optionally, after determining the second shift correction amount of the reference voltage value based on the bus voltage and the bus voltage reference value, the method further includes:

[0106] The second translation correction is subjected to amplitude limiting control to obtain the amplitude-limited second translation correction; and the amplitude-limited second translation correction is used to perform translation correction on the initial droop curve.

[0107] like Figure 8 As shown, in the first quadrant, the vertical axis of the inflection point of the second translation correction corresponds to the maximum offset V. offset2_Uplimit That is, the upper limit of the second translation correction is V. offset2_Uplimit At this point, the horizontal axis corresponds to the maximum SOC difference ΔV_max. In the third quadrant, the vertical axis at the turning point of the second translation correction corresponds to the minimum offset V. offset2_Downlimit That is, the lower limit of the second translation correction is V. offset2_DownlimitAt this point, the horizontal axis corresponds to the largest negative difference in SOC, -ΔV_max.

[0108] Specifically, limiting the second translation correction amount can prevent curve distortion or unreasonable voltage output caused by excessive correction amount, and ensure the rationality and stability of the correction process.

[0109] Figure 10 A flowchart illustrating another control method for a multi-battery module parallel energy storage system provided in an embodiment of the present invention. Figure 10 As shown, based on the above embodiments, optionally, the control method includes:

[0110] S310: Obtain the power required by each battery module in the PCS under both parallel and off-grid conditions.

[0111] S320, Determine the reference voltage value V based on the current output power. oref .

[0112] S330: Obtain the current state parameters of each battery module and the target value for balancing the battery state parameters.

[0113] S340. Determine the first shift correction amount V of the reference voltage value based on the state parameters of each battery module and the difference between the equilibrium target value. offset1 .

[0114] S350: Obtain bus voltage and bus voltage reference value.

[0115] S360. When the bus voltage is not equal to the bus voltage reference value, the DC bus voltage control loop is triggered. Based on the difference between the DC bus voltage and the bus voltage reference value, the second shift correction amount V of the reference voltage value is determined. offset2 .

[0116] S370. Based on the reference voltage value of the battery module, the first translation correction amount, and the second translation correction amount, the final voltage reference value offset V is obtained. off_fin_SOCX Then, based on the corrected droop curve and total output power limit corresponding to each battery module, the target reference voltage value is determined.

[0117] S380 controls the power redistribution and balancing of each battery module based on the target reference voltage value, enabling the multi-battery module parallel energy storage system to reach a new stable operating point.

[0118] Specifically, Figure 11 This is a schematic diagram of another modified sag curve provided in an embodiment of the present invention. For example... Figure 11 As shown, taking a multi-battery module including two battery modules with different SOCs as an example, the power P required by the PCS from each battery module is obtained from the power acquisition unit.o And based on the initial droop curve of each battery module, the reference voltage value of the battery is found to be V. oref That is, the point pointed to by the black arrow in the diagram, where P is satisfied. o =2*P1. Then, based on the SOC of the two battery modules and the bus voltage V... BUS The final translation correction for each battery module is determined by the first and second translation correction curves. Calculations show that the initial droop curve of the first battery module was ultimately shifted downwards by V. off_fin_SOC1 The initial sag curve of the second battery module was eventually shifted upward by V. off_fin_SOC2 .

[0119] Because the PCS requires each battery module to output power of P o By combining the droop curve after translation correction, the reference value of the bus voltage at this time can be found to be V. oref_fin (The point indicated by the blue arrow), and satisfies P o =2*P1=P2-P3. At this point, the discharge power P2 of the battery module with higher SOC (the first battery module) is greater than the discharge power P1 corresponding to the initial droop curve, while the discharge power P3 of the battery module with lower SOC (the second battery module) is less than the discharge power P1 corresponding to the initial droop curve. The second battery module is now operating in charging mode, thus gradually increasing the SOC of the low-SOC battery module. Eventually, the SOC of the two battery modules will become nearly identical, and the droop curves of both battery modules will stabilize at the green dashed line Droop_Target, meaning the green dashed line Droop_Target is the target corrected droop curve for each battery module. Furthermore, experiments show that the technical solution provided in this embodiment of the invention can efficiently balance the SOC of each battery module even when there is an imbalance, ultimately stabilizing its SOC at the target corrected droop curve Droop_Target.

[0120] The technical solution of this invention, by combining the state parameters of each battery module, shifts and corrects the initial droop curve of the battery in different directions to obtain a corrected droop curve. Based on the corrected droop curve of each battery module and the total output power limit, a target reference voltage value and the corresponding power of each battery module are determined. This allows each battery module to adjust its allocated power according to its own situation, enabling power distribution in a multi-battery module parallel energy storage system, while simultaneously achieving bidirectional adjustment and balancing of SOC, thus improving the cycle life of the cells. This technical solution helps achieve efficient, safe, and sustainable operation of battery modules, ensuring stable system operation under various conditions.

[0121] Based on the above embodiments, optionally, after obtaining the modified droop curve Droop_Modified for each battery module, the method further includes: controlling the battery optimizer (DC / DC converter) of the battery module according to the modified droop curve Droop_Modified.

[0122] Specifically, taking the first battery module as an example, its output power is P2 and the corrected droop curve is Droop_SOC1, thus obtaining the final reference voltage value V. oref_fin Based on the final value of the reference voltage V oref_fin The voltage difference is obtained by combining the current output voltage V0 of the multi-battery module. The DC / DC controller module controls the operation of the battery optimizer based on this voltage difference, generates a drive signal and transmits it to the drive signal generator, which controls the operating state of the battery optimizer.

[0123] Figure 12 This is a schematic diagram of a control device for a multi-battery module parallel energy storage system provided in an embodiment of the present invention. Based on the above embodiments, as follows... Figure 12 As shown, the device includes:

[0124] The droop curve correction module 610 is used to control each battery module to perform translation correction in different directions based on the initial droop curve in the parallel and off-grid states, combined with the state parameters of each battery module itself, to obtain the corrected droop curve.

[0125] The power distribution and equalization control module 620 is used to control the power redistribution and equalization of each battery module according to the corrected droop curve and the total output power limit corresponding to each battery module.

[0126] The control device for the multi-battery module parallel energy storage system provided in the embodiments of the present invention can execute the control method for the multi-battery module parallel energy storage system provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the method.

[0127] Optionally, the sag curve correction module 610 specifically includes:

[0128] The equilibrium target value determination unit is used to determine the equilibrium target value of the battery state parameters based on the state parameters of each battery module.

[0129] The first translation correction determination unit is used to determine the first translation correction amount of the reference voltage of the current battery module based on the battery module's own state parameters and the balanced target value of the battery state parameters.

[0130] The corrected droop curve acquisition unit is used to perform translation correction on the initial droop curve based on the reference voltage value and the first translation correction amount to obtain the corrected droop curve of the current battery module.

[0131] Optionally, the sag curve correction module 610 also includes:

[0132] The first limiting unit is used to limit the first translation correction amount to obtain the first translation correction amount after limiting; and to use the first translation correction amount after limiting to perform translation correction on the initial droop curve.

[0133] Optionally, the sag curve correction module 610 also includes:

[0134] The second translation correction determination unit is used to determine the second translation correction amount of the reference voltage value based on the bus voltage and the bus voltage reference value; and to perform translation correction on the initial droop curve using the first translation correction amount and the second translation correction amount.

[0135] Optionally, the sag curve correction module 610 also includes:

[0136] The second limiting unit is used to limit the second translation correction amount to obtain the limited second translation correction amount; and the limited second translation correction amount is used to perform translation correction on the initial droop curve.

[0137] Optionally, the droop curve acquisition unit is also used to obtain the final voltage reference value offset based on the reference voltage reference value, the first translation correction amount, and the second translation correction amount.

[0138] The initial droop curve is shifted and corrected based on the offset of the final voltage reference value.

[0139] Optionally, the method for obtaining the reference voltage value includes:

[0140] Based on the initial droop curve and the total output power of each battery module, a reference value for the base voltage is determined.

[0141] Optionally, the power distribution and equalization control module 620 is specifically used to determine the target reference voltage value and the corresponding power of each battery module based on the corrected droop curve and the total output power limit corresponding to each battery module; wherein the corresponding power of each battery module can meet the power distribution and equalization requirements.

[0142] This invention also provides a multi-battery module parallel energy storage system, including: multiple battery modules, photovoltaic modules and energy storage converters connected in parallel, wherein the energy storage converters execute the control method of the multi-battery module parallel energy storage system provided in any embodiment of this invention.

[0143] Figure 13This is a schematic diagram of an electronic device provided for an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0144] like Figure 13 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 may also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0145] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0146] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the control methods for a multi-battery module parallel energy storage system.

[0147] In some embodiments, the control method for a multi-battery module parallel energy storage system can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the control method for the multi-battery module parallel energy storage system described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the control method for the multi-battery module parallel energy storage system by any other suitable means (e.g., by means of firmware).

[0148] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0149] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0150] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0151] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0152] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0153] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0154] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0155] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A control method for a multi-battery module parallel energy storage system, characterized in that, include: In both on-grid and off-grid states, based on the state parameters of each battery module, each battery module is controlled to undergo translational correction in different directions on the basis of the initial droop curve, thus obtaining a corrected droop curve. Based on the corrected droop curve and total output power limit corresponding to each battery module, the power redistribution and balancing of each battery module are controlled.

2. The control method for a multi-battery module parallel energy storage system according to claim 1, characterized in that, The process involves combining the state parameters of each battery module to control each battery module to perform translational corrections in different directions based on the initial sag curve, thereby obtaining a corrected sag curve. Specifically, this includes: Based on the state parameters of each battery module, determine the target value for balancing the battery state parameters; Based on the state parameters of the battery module itself and the balanced target value of the battery state parameters, determine the first shift correction amount of the current reference voltage value of the battery module; Based on the reference voltage value and the first translation correction amount, the initial droop curve is translated and corrected to obtain the current corrected droop curve of the battery module.

3. The control method for a multi-battery module parallel energy storage system according to claim 2, characterized in that, After determining the first shift correction amount of the current reference voltage value of the battery module based on the battery module's own state parameters and the balanced target value of the battery state parameters, the method further includes: The first translation correction amount is subjected to amplitude limiting control to obtain the first translation correction amount after amplitude limiting; and the initial droop curve is translated and corrected using the first translation correction amount after amplitude limiting.

4. The control method for a multi-battery module parallel energy storage system according to claim 2, characterized in that, Before performing translation correction on the initial droop curve based on the reference voltage value and the first translation correction amount to obtain the corrected droop curve of the current battery module, the method further includes: Based on the bus voltage and the bus voltage reference value, a second translation correction amount for the reference voltage value is determined; and the initial droop curve is translated and corrected using the first translation correction amount and the second translation correction amount.

5. The control method for a multi-battery module parallel energy storage system according to claim 4, characterized in that, After determining the second shift correction amount of the reference voltage value based on the bus voltage and the bus voltage reference value, the method further includes: The second translation correction amount is subjected to amplitude limiting control to obtain the amplitude-limited second translation correction amount; and the amplitude-limited second translation correction amount is used to perform translation correction on the initial droop curve.

6. The control method for a multi-battery module parallel energy storage system according to claim 4, characterized in that, The step of applying the first translation correction amount and the second translation correction amount to the initial sag curve for translation correction specifically includes: The final voltage reference value offset is obtained based on the reference voltage value, the first translation correction amount, and the second translation correction amount. The initial droop curve is shifted and corrected based on the offset of the final voltage reference value.

7. The control method for a multi-battery module parallel energy storage system according to claim 4, characterized in that, The step of determining the first shift correction amount of the current reference voltage value of the battery module based on the battery module's own state parameters and the balanced target value of the battery state parameters includes: The equilibrium target difference is obtained based on the state parameters of the battery module itself and the equilibrium target value of the battery state parameters. Based on the balance target difference and the first translation correction curve, the first translation correction amount of the current reference voltage value of the battery module is determined; wherein, the first translation correction amount curve represents the correspondence between the balance target difference and the first translation correction amount; And / or, the determination of the second shift correction amount of the reference voltage value based on the bus voltage and the bus voltage reference value includes: Determine the target voltage difference based on the bus voltage and the bus voltage reference value; Based on the voltage target difference and the second translation correction curve, the second translation correction amount of the reference voltage value is determined; wherein, the second translation correction curve characterizes the correspondence between the voltage target difference and the second translation correction amount.

8. The control method for a multi-battery module parallel energy storage system according to any one of claims 2-7, characterized in that, The method for obtaining the reference voltage value includes: The reference voltage value is determined based on the initial droop curve and the total output power of each battery module.

9. The control method for a multi-battery module parallel energy storage system according to claim 1, characterized in that, The step of controlling the power redistribution and balancing of each battery module based on the corrected droop curve and total output power limit corresponding to each battery module includes: Based on the corrected droop curve and total output power limit corresponding to each battery module, the target reference voltage value and the corresponding power of each battery module are determined; wherein the corresponding power of each battery module can meet the power distribution and balancing requirements.

10. The control method for a multi-battery module parallel energy storage system according to claim 1, characterized in that, The step of controlling the power redistribution and balancing of each battery module based on the corrected droop curve and total output power limit corresponding to each battery module specifically includes: Based on the corrected droop curve and total output power limit corresponding to each battery module, the final reference voltage value of each battery module is determined; Based on the final value of the reference voltage and the current output voltage of each battery module, the battery optimizer of the corresponding battery module is controlled.

11. A control device for a multi-battery module parallel energy storage system, characterized in that, include: The droop curve correction module is used to control each battery module to perform translation correction in different directions based on the initial droop curve, in the parallel and off-grid states, combined with the state parameters of each battery module itself, to obtain the corrected droop curve. The power distribution and equalization control module is used to control the power redistribution and equalization of each battery module according to the corrected droop curve and the total output power limit corresponding to each battery module.

12. A multi-battery module parallel energy storage system, characterized in that, include: A plurality of battery modules, photovoltaic modules and energy storage converters connected in parallel, wherein the energy storage converters perform the control method of the multi-battery module parallel energy storage system according to any one of claims 1-10.

13. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the control method for the multi-battery module parallel energy storage system according to any one of claims 1-10.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the control method for the multi-battery module parallel energy storage system according to any one of claims 1-10.

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