Parallel energy storage system power control method and parallel energy storage system

Abstract

The embodiment of the invention discloses a power control method of a parallel energy storage system and the parallel energy storage system. The method comprises the following steps: an energy storage converter host receives a total battery power scheduling instruction, collects battery side actual power reported by each energy storage converter slave and calculates total actual power; generating a corrected total power instruction based on the scheduling instruction and the total actual power, and distributing the corrected total power instruction to each energy storage converter slave; and each energy storage converter slave generates and executes a power execution instruction of the DC / AC module based on the received power reference instruction and the actual power collected by the energy storage converter slave. The battery side total power is ensured to accurately track the scheduling instruction through the system-level closed-loop control, the efficiency conversion error is eliminated through the single-machine-level closed-loop control, the high-precision control of the battery power is realized, the accurate scheduling of the system total power can still be ensured even under the condition that the single-machine power is limited, and the control precision and reliability of the parallel energy storage system are improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of power control, and in particular to a power control method for a parallel energy storage system. Background Technology

[0002] Energy storage systems typically consist of batteries and energy storage converters, with the energy storage converter comprising two stages of sub-converters: DC / DC and DC / AC. These two stages of converters use closed-loop control to dispatch power on the DC side of the battery and on the AC side of the grid / load, respectively, thereby achieving precise power control. To cope with dynamic conditions such as sudden load increases on the AC side, the energy storage converter needs to have a fast dynamic response capability. The conventional approach is to operate the DC / DC converter in an open-loop state and transmit the battery-side power dispatch command to the DC / AC converter in an open-loop manner, allowing the DC / AC converter to execute the battery-side power dispatch.

[0003] However, this conventional approach has the following main drawbacks: First, because the actual operating efficiency of an energy storage converter is affected by a combination of factors such as switching device losses, passive component losses, current load rate, and temperature, its efficiency characteristics exhibit significant nonlinearity and time-varying characteristics, making it difficult to accurately characterize with a fixed value or a simple formula. In practical applications, the charge / discharge efficiency is usually simplified to the converter's maximum efficiency point or a certain empirical constant. Using a fixed efficiency value for power conversion ignores the dynamic changes in efficiency during actual operation, inevitably introducing a steady-state error between the expected battery power and the actual power on the battery side, reducing power control accuracy, and thus affecting the accuracy of battery power scheduling.

[0004] Secondly, in parallel energy storage systems with shared battery sides, the system master unit needs to uniformly schedule the total power on the battery side. In this case, each energy storage converter in the system must not only respond to the master unit's scheduling commands but also ensure that its battery-side power does not exceed its own hardware limits. When a converter in the system triggers a power limit due to battery performance or its own conditions, its actual output capacity will be lower than the command value issued by the master unit. If the upper-level controller fails to detect and redistribute the total power command in a timely manner, the actual total power output on the battery side will fail to reach the expected target, resulting in a significant deviation in system-level total power control and failure to meet scheduling requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a power control method for a parallel energy storage system, which can solve at least some of the defects in the existing power control schemes for parallel energy storage systems.

[0006] In a first aspect, embodiments of the present invention provide a power control method for a parallel energy storage system, the parallel energy storage system comprising N parallel energy storage converters, where N>1, and each energy storage converter comprising a DC / DC module and a DC / AC module; the method comprising the following steps: receiving a total battery power scheduling command and acquiring the actual battery-side power reported by each energy storage converter slave, and calculating the total actual battery-side power; generating a corrected total power command based on the total battery power scheduling command and the total actual battery-side power; allocating the corrected total power command to each energy storage converter slave, and generating a battery-side power reference command for each energy storage converter slave; sending the battery-side power reference command to the corresponding energy storage converter, so that the corresponding energy storage converter generates and executes a power execution command for the corresponding DC / AC module based on the received battery-side power reference command and its own collected actual battery-side power.

[0007] Optionally, generating a corrected total power command based on the total battery power scheduling command and the total actual power on the battery side includes: calculating the difference between the total battery power scheduling command and the total actual power on the battery side to obtain a total power error; inputting the total power error into a system-level closed-loop controller for adjustment to generate a correction amount; and superimposing the total battery power scheduling command and the correction amount to generate the corrected total power command; the system-level closed-loop controller includes a PI controller and a PID controller.

[0008] Optionally, the step of allocating the corrected total power command to each energy storage converter slave and generating a battery-side power reference command for each energy storage converter slave includes: allocating the corrected total power command to each energy storage converter slave according to the capacity ratio of each energy storage converter slave, and generating a battery-side power reference command for each energy storage converter slave.

[0009] Optionally, the formula for calculating the battery-side power reference command of the j-th energy storage converter slave is:

[0010] Among them, P bat_ref_j For the battery-side power reference command of the j-th energy storage converter slave, P total_corrected The corrected total power command, cap j Let be the rated capacity of the j-th energy storage converter.

[0011] Optionally, sending the battery-side power reference command to the corresponding energy storage converter, so that the corresponding energy storage converter generates and executes the power execution command of the corresponding DC / AC module based on the received battery-side power reference command and the actual battery-side power it collects, includes: the energy storage converter host sending the battery-side power reference command to the corresponding energy storage converter; the corresponding energy storage converter calculating the difference between the battery-side power reference command and the actual battery-side power to obtain the single-unit power error; the corresponding energy storage converter inputting the single-unit power error into a single-unit level closed-loop controller for adjustment to generate a single-unit correction value; the corresponding energy storage converter superimposing the battery-side power reference command and the single-unit correction value to generate the power execution command; the single-unit level closed-loop controller includes a PI controller and a PID controller.

[0012] Optionally, the method further includes: when a power signal reporting timeout or communication interruption is detected in a certain energy storage converter slave, suspending the power command allocation to the certain energy storage converter slave; and using the historical power value of the certain energy storage converter slave as a fixed value in the calculation of the total actual power on the battery side.

[0013] Optionally, the method further includes: when the actual power on the battery side of a certain energy storage converter slave reaches a preset power limit and cannot respond to the corresponding power execution command, increasing the corrected total power command to increase the power command allocation to other energy storage converter slaves, so that the total actual power on the battery side keeps tracking the total battery power scheduling command.

[0014] In a second aspect, embodiments of the present invention provide an electronic device, comprising: at least one processor; at least one network interface communicatively connected to a corresponding processor; and a memory communicatively connected to the at least one processor; wherein the network interface is used to establish a communication connection between the processor and other external devices; the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform a power control method for a parallel energy storage system as described in the first aspect.

[0015] Thirdly, embodiments of the present invention provide a non-volatile computer storage medium storing computer-executable instructions, which are executed by one or more processors to cause the one or more processors to perform the power control method for the parallel energy storage system as described in the first aspect.

[0016] Fourthly, embodiments of the present invention provide a parallel energy storage system, comprising: a battery pack; N parallel energy storage converters, N>1; the battery side of the N parallel energy storage converters is connected to the battery pack, and the grid side is connected to the power grid and the load; one of the N parallel energy storage converters is configured as the energy storage converter master, used to execute the power control method of the parallel energy storage system as described in the first aspect.

[0017] The beneficial effects of the embodiments of the present invention are as follows: Unlike the prior art, the embodiments of the present invention ensure that the total power of the battery side accurately tracks the scheduling command through system-level closed-loop control, and eliminate efficiency conversion error through single-machine-level closed-loop control, thereby achieving high-precision control of battery power. Even when the power of a single machine is limited, it can still ensure the accurate scheduling of the total power of the system, thus improving the control accuracy and reliability of the parallel energy storage system. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 This is a schematic diagram of a parallel energy storage system provided by an embodiment of the present invention; Figure 2 This is a schematic flowchart of a power control method for a parallel energy storage system provided by an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Detailed Implementation

[0020] To facilitate understanding of this application, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "bottom," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0022] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0023] In some embodiments of this application, reference is made to Figure 1 This paper provides a parallel energy storage system, which includes a battery pack 40, N parallel-operated energy storage converters, and a corresponding communication network. Here, N is a positive integer greater than 1. Figure 1 In the embodiment shown, the N energy storage converters include an energy storage converter master unit 110 and energy storage converter slave units 1 to N-1.

[0024] Specifically, the battery side of the N parallel-connected energy storage converters is connected to the battery pack 40, and the grid side is connected to the grid 20 and the load 30. Power is transferred between the battery pack 40 and the energy storage converters via power lines, and power is also transferred between the energy storage converters and the grid 20 and the load 30 via power lines.

[0025] In some embodiments of this application, the battery pack 40 may include M groups of batteries connected in parallel, where M is a positive integer greater than or equal to 1. For example... Figure 1 As shown, the battery pack 40 includes battery 1, battery 2 to battery M. Among them, battery 1 can be set as the battery host, responsible for collecting the operating information of the M battery packs.

[0026] It should be noted that one of the N parallel energy storage converters is designated as the energy storage converter master 110. The energy storage converter master 110 is used to receive total battery power dispatch commands from the outside and to exchange data with each energy storage converter slave through the internal communication network of the energy storage converter.

[0027] As an example, and not a limitation, each energy storage converter includes a DC / DC module and a DC / AC module. The DC / DC module is responsible for power regulation on the battery side, and the DC / AC module is responsible for power control on the grid side. The two are decoupled through an intermediate DC bus.

[0028] In some embodiments of this application, the parallel energy storage system further includes a communication network. The communication network includes external communication between the energy storage converter and the battery pack, internal communication between the energy storage converter and the battery, and internal communication between the batteries. The energy storage converter master 110 interacts with the battery master in the battery pack 40 through an external communication interface, and distributes commands and collects data with each energy storage converter slave through internal communication.

[0029] Specifically, the energy storage converter master unit 110 collects the actual battery-side power reported by each energy storage converter slave unit through the internal communication network of the energy storage converter, and sends the allocated power reference command to each energy storage converter slave unit. Each energy storage converter slave unit performs corresponding power control according to the received power reference command.

[0030] In some embodiments of this application, reference is made to Figure 2 A power control method for a parallel energy storage system is provided. By way of example and not limitation, this method is applied to the parallel energy storage system provided in the previous embodiment and is executed by the energy storage converter host 110.

[0031] The power control method for this parallel energy storage system specifically includes the following steps: Step S100: Receive the total battery power scheduling command, obtain the actual battery-side power reported by each energy storage converter slave, and calculate the total actual battery-side power.

[0032] In some embodiments of this application, the energy storage converter host 110 receives a total battery power dispatch command from an external upper-level controller. The total battery power dispatch command represents the total charging or discharging power required by the parallel energy storage system. By way of example and not limitation, a positive total battery power dispatch command indicates that the battery needs to be discharged; a negative total battery power dispatch command indicates that the battery needs to be charged.

[0033] Meanwhile, the energy storage converter host 110 collects the actual battery-side power reported by each energy storage converter slave in real time through the internal communication network. The actual battery-side power is the local battery-side DC power obtained by each energy storage converter slave in real time through sensors.

[0034] Specifically, the energy storage converter master unit 110 sums up the actual battery-side power reported by the slave units from the first to the (N-1)th energy storage converters, as well as the actual battery-side power measured by the master unit 110 itself, to calculate the total actual battery-side power. The total actual battery-side power reflects the total power currently actually output or absorbed by the parallel energy storage system.

[0035] Step S200: Generate a corrected total power command based on the total battery power scheduling command and the total actual power on the battery side.

[0036] In some embodiments of this application, the energy storage converter host 110 compares the total battery power dispatch command with the total actual power on the battery side to generate a corrected total power command. The corrected total power command is used to compensate for the deviation between the total actual power on the battery side and the total battery power dispatch command.

[0037] By generating a corrected total power command, system-level closed-loop control can be achieved. When there is a deviation between the actual total power on the battery side and the total battery power dispatch command, the energy storage converter host 110 corrects the total power command in real time to ensure that the actual total power on the battery side can accurately track the total battery power dispatch command.

[0038] As an example rather than a limitation, even if a slave device of an energy storage converter cannot fully respond to the allocated power command due to reaching the power limit, the system-level closed-loop control can still adjust the power command allocation to other slave devices of the energy storage converter by correcting the total power command, thereby maintaining accurate tracking of the total actual power on the battery side to the total battery power scheduling command.

[0039] Step S300: Distribute the corrected total power command to each energy storage converter slave and generate the battery-side power reference command for each energy storage converter slave.

[0040] In some embodiments of this application, the energy storage converter master 110 distributes the corrected total power command to N energy storage converters according to a preset allocation strategy, generating a battery-side power reference command for each energy storage converter slave. The battery-side power reference command represents the power target value that each energy storage converter slave needs to execute on the battery side.

[0041] Specifically, the energy storage converter master unit 110 rationally distributes the corrected total power command to each energy storage converter slave unit based on parameters such as the operating status and capacity of each energy storage converter. The distribution strategy can be selected according to actual application requirements to achieve reasonable power scheduling.

[0042] Step S400: Send the battery-side power reference command to the corresponding energy storage converter, so that the corresponding energy storage converter can generate and execute the power execution command of the corresponding DC / AC module based on the received battery-side power reference command and the actual battery-side power it collects.

[0043] In some embodiments of this application, the energy storage converter master 110 sends a battery-side power reference command to the corresponding energy storage converter slave via an internal communication network. After receiving the battery-side power reference command, each energy storage converter slave collects its own actual battery-side power in real time.

[0044] Specifically, each energy storage converter slave compares the received battery-side power reference command with its own collected actual battery-side power, and generates a corresponding power execution command for the DC / AC module based on the deviation between the two. The power execution command controls the DC / AC module to perform corresponding power regulation actions, enabling the battery to output electrical energy to the grid or load, or the grid to supply electrical energy to the battery.

[0045] It is easy to understand that each energy storage converter slave unit can achieve precise power control at the single-unit level through local closed-loop control. The single-unit level closed-loop control compensates in real time for power execution errors caused by factors such as changes in energy storage converter efficiency and differences in device parameters, ensuring that the actual power on the battery side accurately tracks the battery side power reference command.

[0046] As an example rather than a limitation, each energy storage converter slave device continuously collects its own actual battery power while performing power control, and reports the collected actual battery power to the energy storage converter master device 110, thereby forming a continuously operating two-level closed-loop control system.

[0047] In some embodiments of this application, the power control method further includes fault-tolerant processing for communication interruption or timeout. Specifically, when the energy storage converter master 110 detects a power signal reporting timeout or communication interruption from a certain energy storage converter slave, it executes the corresponding fault-tolerant strategy to ensure the stable operation of the parallel energy storage system.

[0048] As an example and not a limitation, in step S100, when the energy storage converter master 110 collects the actual battery-side power reported by each energy storage converter slave through the internal communication network, it will monitor the communication status of each energy storage converter slave in real time. When it is detected that an energy storage converter slave has not reported a power signal within a preset time, or when the communication link is interrupted, it is determined that the energy storage converter slave has a communication abnormality.

[0049] When a communication failure occurs in a slave device of the energy storage converter, the master device 110 of the energy storage converter suspends the allocation of power commands to that slave device. Specifically, in step S300, when the master device 110 allocates the corrected total power command to each slave device of the energy storage converter, it no longer allocates power commands to the slave device of the energy storage converter that has experienced a communication failure, thereby avoiding power control failure caused by the communication failure.

[0050] In some embodiments of this application, to ensure the continuity and accuracy of the calculation of the total actual power on the battery side, the energy storage converter master 110 uses the historical power value of the energy storage converter slave that experienced a communication anomaly as a fixed value in the calculation of the total actual power on the battery side. The historical power value is the actual power on the battery side last successfully reported by the energy storage converter slave before the communication anomaly occurred.

[0051] By using historical power values ​​as fixed values ​​in the calculation, the normal operation of the system-level closed-loop control can be maintained during communication anomalies, allowing the other normally functioning energy storage converters in the parallel energy storage system to continue performing power dispatching tasks, thus ensuring the overall stability of the system.

[0052] As an example and not a limitation, the energy storage converter host 110 can also generate an alarm signal when a communication anomaly is detected, notifying the upper-level controller or maintenance personnel to handle the abnormal situation in a timely manner. When communication is restored, the energy storage converter host 110 resumes the power command allocation to the energy storage converter slave and re-collects its real-time battery-side actual power for calculation.

[0053] In other embodiments of this application, the power control method further includes a dynamic compensation mechanism when the power of a single unit is limited. Specifically, when the actual power on the battery side of a slave unit of an energy storage converter reaches a preset power limit and cannot respond to the corresponding power execution command, the system-level closed-loop control automatically performs power redistribution to maintain accurate tracking of the total actual power on the battery side to the total battery power scheduling command.

[0054] As an example rather than a limitation, the preset power limit can be determined based on factors such as the hardware allowable range of the energy storage converter, the charging and discharging capacity of the battery, and temperature protection requirements. When the actual power of a slave energy storage converter reaches the preset power limit due to its own conditions or battery performance limitations, the slave energy storage converter cannot continue to increase or decrease its power output, resulting in its actual power on the battery side not being able to fully respond to the power execution command generated in step S400.

[0055] Specifically, in step S100, the actual battery power reported by the slave unit of the energy storage converter, collected by the energy storage converter master 110, will remain near the power limit and will not reach the battery power reference command value allocated to it. Therefore, the total actual battery power calculated in step S200 will be lower than the total battery power scheduling command, resulting in a total power deviation.

[0056] In some embodiments of this application, the energy storage converter host 110 generates a corrected total power command in step S200 based on the deviation between the total battery power dispatch command and the total actual power on the battery side. Specifically, when the system-level closed-loop control detects that the total actual power on the battery side is lower than the total battery power dispatch command, it increases the corrected total power command to make it greater than the original total battery power dispatch command.

[0057] In step S300, the energy storage converter master 110 distributes the increased and corrected total power command to each energy storage converter slave. For energy storage converter slaves that have reached their power limits, the battery-side power reference command they are allocated may still exceed their actual capacity, but the slave will operate at the power limit. For other energy storage converter slaves that have not reached their power limits, the battery-side power reference command they are allocated will be increased accordingly, thereby increasing the power command allocation to other energy storage converter slaves.

[0058] As an example, and not a limitation, by increasing the power command allocation to other energy storage converter slaves, the total power gap caused by the power limitation of a single unit can be dynamically compensated, ensuring that the total actual power on the battery side keeps track of the total battery power dispatch command. System-level closed-loop control continuously detects and corrects power deviations, ensuring that even when the power of some energy storage converter slaves is limited, the parallel energy storage system can still accurately complete the power dispatch task.

[0059] In some embodiments of this application, through the cooperation of the aforementioned communication fault-tolerance mechanism and power limitation response mechanism, the power control method can maintain stable operation under various abnormal operating conditions, improving the reliability and robustness of the parallel energy storage system. System-level closed-loop control automatically responds to single-unit anomalies or power limitations without requiring manual intervention from the upper-level controller, achieving a highly automated power scheduling management.

[0060] In some embodiments of this application, step S200 specifically includes the following steps: Step S210: Calculate the difference between the total battery power scheduling command and the total actual power on the battery side to obtain the total power error.

[0061] In some embodiments of this application, the energy storage converter host 110 compares the total battery power scheduling command received in step S100 with the calculated total actual power on the battery side, calculates the difference between the two, and obtains the total power error. The total power error reflects the deviation between the current actual total output power of the parallel energy storage system and the expected total output power.

[0062] Specifically, the total power error equals the total battery power dispatch command minus the total actual battery power. When the total power error is positive, it means that the total actual battery power is lower than the total battery power dispatch command, and the parallel energy storage system needs to increase its power output; when the total power error is negative, it means that the total actual battery power is higher than the total battery power dispatch command, and the parallel energy storage system needs to reduce its power output.

[0063] As an example and not a limitation, the causes of total power error may include: power conversion error caused by dynamic changes in the efficiency of energy storage converters, power gap caused by limited power of individual units, power disturbance caused by load fluctuations, and factors such as communication delays or measurement errors.

[0064] Step S220: Input the total power error into the system-level closed-loop controller for adjustment to generate a correction value.

[0065] In some embodiments of this application, the energy storage converter host 110 inputs the total power error calculated in step S210 into the system-level closed-loop controller. The system-level closed-loop controller processes and adjusts the total power error to generate a correction amount for compensating for the power deviation.

[0066] Specifically, system-level closed-loop controllers include PI controllers and PID controllers. PI controllers contain proportional and integral elements, while PID controllers add a derivative element to the PI controller. As examples and not limitations, the type of controller can be selected based on actual application requirements and control performance specifications.

[0067] In some embodiments of this application, when a PI controller is used, the correction amount is obtained by adding the outputs of the proportional and integral components. The proportional component amplifies the total power error proportionally and outputs a correction component proportional to the total power error for rapid response to power deviation. The integral component integrates the total power error and outputs a correction component proportional to the accumulated value of the total power error for eliminating steady-state error.

[0068] The proportional gain of the proportional element determines the system's response speed; a larger proportional gain results in a faster response, but an excessively large proportional gain may lead to overshoot or oscillation. The integral gain of the integral element determines the speed at which steady-state error is eliminated; a larger integral gain results in faster elimination of steady-state error, but an excessively large integral gain may lead to decreased system stability.

[0069] As an example, and not a limitation, when using a PID controller, the correction also includes the output of the derivative element. The derivative element processes the rate of change of the total power error and outputs a correction component proportional to the rate of change of the total power error. This component is used to predict the trend of power deviation changes, perform corrections in advance, improve the dynamic performance of the system, and reduce overshoot and settling time.

[0070] In some embodiments of this application, the control parameters of the system-level closed-loop controller can be tuned according to the actual operating characteristics of the parallel energy storage system. The control parameters include proportional coefficient, integral coefficient, and derivative coefficient. By reasonably setting the control parameters, rapid response and high-precision control can be achieved while ensuring system stability.

[0071] Step S230: Superimpose the total battery power scheduling command with the correction amount to generate the corrected total power command.

[0072] In some embodiments of this application, the energy storage converter host 110 superimposes the total battery power scheduling command received in step S100 with the correction amount generated in step S220 to obtain the corrected total power command.

[0073] Specifically, the corrected total power command equals the total battery power scheduling command plus the correction amount. When the correction amount is positive, the corrected total power command is greater than the original total battery power scheduling command, used to compensate for insufficient power; when the correction amount is negative, the corrected total power command is less than the original total battery power scheduling command, used to suppress excessive power.

[0074] By directly superimposing the total battery power dispatch command as a feedforward signal onto the output of the system-level closed-loop controller, a composite control structure of feedforward and feedback is formed. Feedforward control can quickly respond to changes in external power dispatch commands, greatly improving the system's response speed; feedback control corrects deviations in the power execution process in real time, ensuring control accuracy.

[0075] As an example, and not a limitation, in the initial stage of operation of a parallel energy storage system or when there are significant changes in the total battery power dispatch command, the feedforward circuit can quickly transmit the power command to the slave devices of each energy storage converter, enabling the system to rapidly establish the corresponding power output. Simultaneously, the feedback circuit continuously monitors the deviation between the actual total power on the battery side and the total battery power dispatch command, and continuously corrects the power command through closed-loop regulation, ultimately ensuring that the actual total power on the battery side accurately converges to the total battery power dispatch command.

[0076] In some embodiments of this application, the combined feedforward and feedback control structure combines the advantages of speed and accuracy. Feedforward control provides rapid dynamic response capability, meeting the needs of energy storage systems to cope with dynamic operating conditions such as sudden load increases on the AC side; feedback control provides accurate steady-state tracking capability, solving the problem of reduced power control accuracy caused by efficiency conversion errors in open-loop control.

[0077] Through the system-level closed-loop control process from steps S210 to S230, the energy storage converter master 110 can generate a corrected total power command in real time based on the deviation between the total battery power dispatch command and the actual total power on the battery side. The corrected total power command is distributed to each energy storage converter slave in step S300, ensuring that the overall power output of the parallel energy storage system accurately tracks the external dispatch requirements.

[0078] In some embodiments of this application, the system-level closed-loop control adjustment process is continuous. After step S400 is completed, each energy storage converter slave reports the updated actual battery power to the energy storage converter master 110. The process returns to step S100 to recalculate the total actual battery power, and then the system-level closed-loop control is executed again in step S200 to form a closed-loop feedback loop, thereby achieving dynamic tracking and precise control of the total power.

[0079] In some embodiments of this application, step S300 specifically includes the following steps: Step S310: Obtain the capacity information of each energy storage converter.

[0080] In some embodiments of this application, the energy storage converter host 110 acquires the rated capacity information of each energy storage converter in the parallel energy storage system. Specifically, the rated capacity of the energy storage converter is determined by its hardware design parameters, including the power rating of the DC / DC module and DC / AC module, the current capacity of the switching devices, the cooling capacity of the heat dissipation system, and other factors.

[0081] The energy storage converter host 110 can obtain the rated capacity information of each energy storage converter in various ways. As an example, and not a limitation, the energy storage converter host 110 can query the rated capacity parameters of each energy storage converter slave device via its internal communication network during the system initialization phase, and save the query results in its local memory. Upon receiving the query request, each energy storage converter slave device will send its own rated capacity information back to the energy storage converter host 110 via the communication network.

[0082] As an example and not a limitation, in a parallel energy storage system containing N energy storage converters, the capacity information obtained by the energy storage converter master 110 includes: the rated capacity of the energy storage converter master 110 itself, the rated capacity of the first energy storage converter slave, the rated capacity of the second energy storage converter slave, and so on up to the rated capacity of the (N-1)th energy storage converter slave.

[0083] Step S320: Calculate the capacity allocation coefficient of each energy storage converter.

[0084] In some embodiments of this application, the energy storage converter host 110 calculates the capacity allocation coefficient of each energy storage converter based on the rated capacity information of each energy storage converter obtained in step S310. The capacity allocation coefficient represents the proportion that each energy storage converter should account for in the total power distribution.

[0085] Specifically, the energy storage converter main unit 110 first calculates the sum of the rated capacities of all energy storage converters, that is, the sum of the rated capacities of the energy storage converters from the 1st to the Nth. For the jth energy storage converter, its capacity allocation factor is equal to its rated capacity divided by the sum of the rated capacities of all energy storage converters. The value of the capacity allocation factor ranges from 0 to 1, and the sum of the capacity allocation factors of all energy storage converters equals 1.

[0086] As an example, and not a limitation, when all energy storage converters have the same rated capacity, the capacity allocation coefficient for each energy storage converter is equal to 1 / N, i.e., an average allocation strategy is adopted. When the rated capacities of the energy storage converters are different, the energy storage converters with larger capacities have larger allocation coefficients, and the energy storage converters with smaller capacities have smaller allocation coefficients, achieving a reasonable allocation according to capacity proportions.

[0087] In some embodiments of this application, the capacity allocation coefficient can be calculated and saved once during the system initialization phase, and the saved capacity allocation coefficient can be directly used in subsequent power allocation processes without repeated calculation. When the configuration of the parallel energy storage system changes, such as increasing or decreasing the number of energy storage converters or replacing energy storage converters with different capacities, the energy storage converter host 110 recalculates the capacity allocation coefficient of each energy storage converter.

[0088] Step S330: According to the capacity allocation coefficient, the corrected total power command is allocated to each energy storage converter slave, and the battery-side power reference command of each energy storage converter slave is generated.

[0089] In some embodiments of this application, the energy storage converter master 110 allocates the corrected total power command generated in step S200 to each energy storage converter slave according to the capacity allocation coefficient calculated in step S320. Specifically, for the j-th energy storage converter slave, its battery-side power reference command is equal to the corrected total power command multiplied by the capacity allocation coefficient of that energy storage converter. The battery-side power reference command reflects the power target value that the energy storage converter slave needs to execute on the battery side.

[0090] In some embodiments of this application, the formula for calculating the battery-side power reference command of the j-th energy storage converter slave can be expressed as:

[0091] Among them, P bat_ref_j For the battery-side power reference command of the j-th energy storage converter slave, P total_corrected The corrected total power command, cap j Let i be the rated capacity of the j-th energy storage converter, and i be the number of the energy storage converter.

[0092] The battery-side power reference command allocated to each energy storage converter slave is proportional to its rated capacity and inversely proportional to the total capacity of all energy storage converters in the system.

[0093] In some embodiments of this application, the energy storage converter master 110 performs the aforementioned power allocation calculation on all energy storage converter slaves. For the energy storage converter master 110 itself, its battery-side power reference command is also calculated according to the capacity allocation factor. Therefore, all N energy storage converters obtain their respective battery-side power reference commands.

[0094] Specifically, the energy storage converter master unit 110 sends the calculated battery-side power reference commands for each energy storage converter slave unit to the corresponding energy storage converter slave unit via the internal communication network. After receiving the battery-side power reference commands, each energy storage converter slave unit performs the corresponding single-unit closed-loop control and power execution operation in step S400.

[0095] As an example, and not a limitation, the capacity-ratio allocation strategy also has good scalability. When a new energy storage converter is added to a parallel energy storage system, the energy storage converter host 110 re-acquires the rated capacity information of all energy storage converters in the system, recalculates the capacity allocation coefficient, and automatically incorporates the newly added energy storage converter into the power allocation system. The newly added energy storage converter receives a corresponding power allocation ratio based on its rated capacity, without requiring additional adjustments to the existing energy storage converters, thus achieving smooth system expansion.

[0096] It is easy to understand that when a slave energy storage converter needs to be taken out of operation due to maintenance or failure, the master energy storage converter 110 excludes that energy storage converter from the power allocation calculation and recalculates the capacity allocation coefficient of the remaining energy storage converters. The remaining energy storage converters obtain updated battery-side power reference commands according to the new capacity allocation coefficients, and automatically share the power tasks originally undertaken by the out-of-operation energy storage converter, ensuring the continuous and stable operation of the parallel energy storage system.

[0097] In some embodiments of this application, step S400 specifically includes the following steps: Step S410: The energy storage converter host sends the battery-side power reference command to the corresponding energy storage converter.

[0098] In some embodiments of this application, after the energy storage converter host 110 completes the power distribution calculation in step S300, it sends the battery-side power reference command of each energy storage converter slave to the corresponding energy storage converter slave through the internal communication network.

[0099] Specifically, the energy storage converter master 110 sends the battery-side power reference command of the first energy storage converter slave to the first energy storage converter slave, sends the battery-side power reference command of the second energy storage converter slave to the second energy storage converter slave, and so on, sending the battery-side power reference command of the (N-1)th energy storage converter slave to the (N-1)th energy storage converter slave.

[0100] In some embodiments of this application, to ensure real-time communication, the energy storage converter master 110 can send battery-side power reference commands to each energy storage converter slave at a fixed period, such as updating every 10 milliseconds, 20 milliseconds, or 50 milliseconds. To ensure communication reliability, the communication message can include a cyclic redundancy check code or other error detection mechanism. Each energy storage converter slave verifies the received communication message to ensure the accuracy of the command data.

[0101] Step S420: The corresponding energy storage converter calculates the difference between the battery-side power reference command and the actual battery-side power to obtain the single-unit power error.

[0102] In some embodiments of this application, after receiving the battery-side power reference command issued by the energy storage converter master 110, each energy storage converter slave device collects its own actual battery-side power in real time through local sensors. The actual battery-side power is calculated by measuring the voltage and current on the battery side.

[0103] Specifically, each energy storage converter slave unit is equipped with a voltage sensor and a current sensor at the output terminal of the DC / DC module or the battery connection terminal. The voltage sensor measures the DC voltage value on the battery side in real time, and the current sensor measures the DC current value flowing through the battery side in real time. The controller of the energy storage converter slave unit collects the measurement signals from the voltage sensor and the current sensor and calculates the actual power on the battery side. The actual power on the battery side is equal to the product of the battery side voltage and the battery side current.

[0104] In some embodiments of this application, the energy storage converter slave compares the battery-side power reference command received in step S410 with the real-time acquired actual battery-side power, calculates the difference between the two, and obtains the single-unit power error. The single-unit power error reflects the deviation between the current actual power and the expected power of the energy storage converter slave.

[0105] Specifically, the single-unit power error equals the battery-side power reference command minus the actual battery-side power. When the single-unit power error is positive, it indicates that the actual battery-side power is lower than the battery-side power reference command, and the energy storage converter slave needs to increase its power output; when the single-unit power error is negative, it indicates that the actual battery-side power is higher than the battery-side power reference command, and the energy storage converter slave needs to decrease its power output.

[0106] Step S430: The corresponding energy storage converter inputs the single-unit power error into the single-unit closed-loop controller for adjustment, generating a single-unit correction value.

[0107] In some embodiments of this application, each energy storage converter slave inputs the single-unit power error calculated in step S420 into the single-unit level closed-loop controller. The single-unit level closed-loop controller processes and adjusts the single-unit power error to generate a single-unit correction amount for compensating for power deviation.

[0108] In some embodiments of this application, when a PI controller is used, the single-unit correction amount is obtained by adding the outputs of the proportional and integral components. The proportional component amplifies the single-unit power error proportionally and outputs a correction component proportional to the single-unit power error for rapid response to power deviation. The integral component integrates the single-unit power error and outputs a correction component proportional to the cumulative value of the single-unit power error for eliminating steady-state error.

[0109] It's easy to understand that the proportional element can immediately generate control action based on the current power deviation; the larger the proportional coefficient, the faster the system responds to the power deviation. The integral element can accumulate historical power deviation information; as long as a power deviation exists, the output of the integral element will continue to accumulate until the power deviation is completely eliminated. Through the synergistic effect of the proportional and integral elements, the PI controller can achieve fast response and zero steady-state error control.

[0110] As an example, and not a limitation, when using a PID controller, the single-unit correction also includes the output of the derivative element. The derivative element processes the rate of change of the single-unit power error and outputs a correction component proportional to that rate of change. The derivative element can predict the trend of power deviation changes and correct for them before significant changes occur, improving the system's dynamic performance and reducing overshoot and oscillation.

[0111] It's easy to understand that the control parameters of a single-machine-level closed-loop controller can be coordinated with those of a system-level closed-loop controller. As an example, and not a limitation, the response speed of a single-machine-level closed-loop controller is typically set to be faster than that of the system-level closed-loop controller to quickly track changes in the battery-side power reference command. The system-level closed-loop controller has a relatively slower response speed and is used to stably regulate the total power of the entire parallel energy storage system. Through the appropriate configuration of the response speeds of the two-stage closed-loop controllers, an organic combination of rapid local response and stable global control can be achieved.

[0112] Specifically, the single-unit closed-loop controller processes the single-unit power error and generates a single-unit correction value that can dynamically compensate for various power deviations existing in the slave unit of the energy storage converter. The single-unit correction value will be superimposed with the battery-side power reference command in step S440 to generate the power execution command for the DC / AC module.

[0113] Step S440: The corresponding energy storage converter superimposes the battery-side power reference command with the single-unit correction value to generate a power execution command.

[0114] In some embodiments of this application, each energy storage converter slave device superimposes the battery-side power reference command received in step S410 with the single-machine correction amount generated in step S430 to obtain a power execution command. The power execution command is the actual power control command issued to the DC / AC module.

[0115] Specifically, the power execution command equals the battery-side power reference command plus the single-unit correction amount. When the single-unit correction amount is positive, the power execution command is greater than the battery-side power reference command, used to compensate for insufficient power; when the single-unit correction amount is negative, the power execution command is less than the battery-side power reference command, used to suppress excessive power.

[0116] By directly superimposing the battery-side power reference command as a feedforward signal onto the output of the single-machine-level closed-loop controller, a composite control structure of feedforward and feedback is formed. Feedforward control can quickly respond to changes in the power reference command issued by the energy storage converter host 110, enabling the DC / AC module to rapidly establish the corresponding power output; feedback control corrects deviations in the power execution process in real time, ensuring that the actual power on the battery side accurately tracks the battery-side power reference command.

[0117] In some embodiments of this application, the feedforward plus feedback composite control structure achieves automatic compensation for efficiency conversion errors at the single-machine level. When the efficiency of the energy storage converter slave changes, the actual power on the battery side will deviate from the battery side power reference command, resulting in a single-machine power error. The single-machine level closed-loop controller adjusts the single-machine power error, generates a single-machine correction value, and dynamically adjusts the power execution command so that the actual power on the battery side converges back to the battery side power reference command.

[0118] It's easy to understand that single-machine-level closed-loop control eliminates the reliance on fixed efficiency values, directly using the actual power on the battery side as feedback for closed-loop regulation. Regardless of changes in the efficiency of the energy storage converter slave, the single-machine-level closed-loop controller can automatically adjust the power execution command, compensate for power deviations caused by efficiency changes, and achieve precise tracking of the actual power on the battery side with the battery side power reference command.

[0119] As an example, and not a limitation, during the initial operation of the energy storage converter slave, efficiency may be low, and the actual power on the battery side may be lower than the battery side power reference command. After detecting the single-unit power error, the single-unit closed-loop controller generates a positive single-unit correction, increases the power execution command, improves the power output of the DC / AC module, compensates for efficiency losses, and brings the actual power on the battery side up to the battery side power reference command. As the energy storage converter slave enters a stable operating phase and efficiency gradually improves, the single-unit closed-loop controller automatically reduces the single-unit correction to maintain stable tracking of the actual power on the battery side.

[0120] Step S450: The DC / AC module executes the power execution command.

[0121] In some embodiments of this application, each energy storage converter slave sends the power execution command generated in step S440 to the DC / AC module. The DC / AC module performs power control according to the power execution command, enabling the battery to output electrical energy to the grid or load, or the grid to supply electrical energy to the battery.

[0122] Specifically, the DC / AC module includes a power control loop and a current control loop. The power control loop receives power execution commands and converts them into corresponding current reference values. The current control loop controls the switching devices of the DC / AC module to turn on and off according to the current reference values, regulating the AC current output to or drawn from the grid side, thereby achieving power control.

[0123] It's easy to understand that a DC / AC module controls the active and reactive power exchanged with the grid by adjusting the amplitude and phase of the output current. When the battery needs to discharge, the DC / AC module controls the phase of the AC current to be in phase with the grid voltage, outputting active power to the grid or load; when the battery needs to charge, the DC / AC module controls the phase of the AC current to be out of phase with the grid voltage, absorbing active power from the grid to charge the battery.

[0124] In some embodiments of this application, while the DC / AC module performs power control, the energy storage converter slave continuously collects the actual power on the battery side through sensors, forming a closed-loop feedback. The collection period of the actual power on the battery side matches the control period of the single-machine-level closed-loop controller, ensuring the real-time performance of the closed-loop control.

[0125] Step S460: The corresponding energy storage converter collects the actual power of its own battery side and reports it to the energy storage converter host.

[0126] In some embodiments of this application, each energy storage converter slave device continuously collects its own actual battery power while performing power control, and reports the collected actual battery power to the energy storage converter host 110 through the internal communication network.

[0127] Specifically, each energy storage converter slave device packages the actual power on the battery side into a communication message and sends it to the energy storage converter master device 110 according to a preset reporting period. The reporting period can be configured according to the control requirements of the system. As an example and not a limitation, the reporting period can be set to 10 milliseconds, 20 milliseconds, 50 milliseconds or other appropriate time intervals.

[0128] After receiving the actual battery-side power reported by each energy storage converter slave, the energy storage converter master 110 returns to step S100 to recalculate the total actual battery-side power. Then, in step S200, it executes system-level closed-loop control to generate a new corrected total power command. The new corrected total power command is distributed to each energy storage converter slave in step S300, and each energy storage converter slave executes a new round of single-unit-level closed-loop control in step S400.

[0129] Unlike existing technologies, the embodiments of the present invention ensure that the total power of the battery side accurately tracks the scheduling command through system-level closed-loop control and eliminate efficiency conversion errors through single-machine-level closed-loop control, thereby achieving high-precision control of battery power. Even when the power of a single machine is limited, it can still guarantee the accurate scheduling of the total power of the system, thus improving the control accuracy and reliability of the parallel energy storage system.

[0130] The present invention also provides an electronic device based on the power control method of the parallel energy storage system described above, the schematic diagram of which is shown below. Figure 3 As shown, the electronic device 100 includes: One or more processors 101, a network interface 102, and a memory 103, Figure 3 The example consists of a processor 101, a network interface 102, and a memory 103.

[0131] The network interface 102 is communicatively connected to the corresponding processor 101, and the processor 101 and the memory 102 can be connected via a bus or other means. Figure 3 Taking the example of a connection between China and Israel via a bus.

[0132] The network interface 102 is used to establish communication connections between the processor 101 and other external devices, including the following types: RJ-45 interface, SC fiber optic interface, AUI interface, FDDI interface and Console interface.

[0133] The memory 103, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. The processor 101 executes various functional applications and data processing of the electronic device by running the non-volatile software programs, instructions, and units stored in the memory 103, thereby implementing the power control method of the parallel energy storage system described in the above method embodiment.

[0134] The memory 103 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the electronic device. Furthermore, the memory 103 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 103 may optionally include memory remotely located relative to the processor 101, and these remote memories can be connected to the electronic device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0135] The one or more units are stored in the memory 103, and when executed by one or more processors 101, they execute the power control method of the parallel energy storage system in any of the above method embodiments.

[0136] The aforementioned electronic device can execute the power control method for the parallel energy storage system provided in the embodiments of the present invention, and has the corresponding program modules and beneficial effects for executing the method. Technical details not described in detail in the electronic device embodiments can be found in the power control method for the parallel energy storage system provided in the embodiments of the present invention.

[0137] This invention also provides a non-volatile computer-readable storage medium, which may be included in the device described in the above embodiments; or it may exist independently and not assembled into the device. The non-volatile computer-readable storage medium carries one or more programs, which, when executed, implement the power control method for the parallel energy storage system according to the embodiments of this disclosure.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above. For the sake of brevity, they are not provided in detail; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method of power control for a parallel energy storage system, characterized by, The parallel energy storage system comprises N parallel energy storage converters, N>1, each energy storage converter comprising a DC / DC module and a DC / AC module; the method comprises the following steps: receiving a total battery power scheduling instruction and obtaining the actual battery-side power reported by each energy storage converter slave, calculating the total actual battery-side power; based on the total battery power scheduling instruction and the total actual battery-side power, generating a corrected total power instruction; distributing the corrected total power instruction to each energy storage converter slave to generate a battery-side power reference instruction for each energy storage converter slave; sending the battery-side power reference instruction to the corresponding energy storage converter to enable the corresponding energy storage converter to generate and execute a power execution instruction for the corresponding DC / AC module based on the received battery-side power reference instruction and the battery-side actual power collected by itself.

2. The method of claim 1, wherein, The method further comprises: when detecting that the power signal reporting of a certain energy storage converter slave is timed out or the communication is interrupted, suspending the power instruction distribution to the certain energy storage converter slave; taking the historical power value of the certain energy storage converter slave as a fixed value to participate in the calculation of the total actual battery-side power. The method further comprises:

3. The method of claim 1, wherein, ​ ​ ​ ​ wherein P bat_ref_j is the battery-side power reference instruction of the jth energy storage converter slave, P total_corrected is the corrected total power instruction, cap j is the rated capacity of the jth energy storage converter.

5. The method of claim 1, wherein, ​ ​ ​ ​ ​ 6. The method of claim 1, wherein, ​ ​ ​ 7. The method of claim 1, wherein, ​ When the actual power of a slave energy storage converter reaches the preset power limit and cannot respond to the corresponding power execution instruction, the corrected total power instruction is increased to increase the power instruction allocation to other energy storage converter slaves, so that the total actual power of the battery side keeps track of the total battery power scheduling instruction.

8. An electronic device, comprising: Comprising: at least one processor; at least one network interface, which is in communication connection with the corresponding processor; and, a memory in communication connection with the at least one processor; wherein, the network interface is used to establish a communication connection between the processor and other external devices; the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the power control method of the parallel energy storage system as claimed in any one of claims 1-7.

9. A non-transitory computer storage medium, comprising: The computer storage medium stores computer executable instructions, which are executed by one or more processors, so that the one or more processors perform the power control method of the parallel energy storage system as claimed in any one of claims 1-7.

10. A parallel energy storage system, characterized by, Comprising: a battery pack; N parallel energy storage converters, N>1; the battery side of the N parallel energy storage converters is connected to the battery pack, the grid side is connected to the grid and the load; one of the N parallel energy storage converters is set as an energy storage converter master, which is used to perform the power control method of the parallel energy storage system as claimed in any one of claims 1-7.

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