A high-efficiency parallel active equalization method for energy storage batteries based on PWM control

Abstract

This invention provides a high-efficiency parallel active balancing method for energy storage batteries based on PWM control, relating to the field of battery energy storage system balancing control technology. The method includes: constructing a series-parallel energy storage battery network; configuring controllable high-frequency power electronic switches at electrical connections to form a bidirectional active balancing topology; collecting system electrical parameters and constructing an energy interaction model using a bidirectional converter and a PWM controllable switching mechanism; based on the model, performing PWM charge-discharge control on battery clusters and individual cells that are not yet in operation to achieve inter-cluster balancing; and then performing refined PWM control on the individual cell switches based on the inter-cluster results to achieve intra-cluster parallel balancing. This invention solves the problem in existing energy storage battery system balancing control strategies that struggle to simultaneously achieve efficient parallel active balancing and inter-cluster balancing of multiple unbalanced cells with different state of charge (SOC), resulting in low balancing circuit utilization, limited energy transfer, and insufficient overall system balancing efficiency.

Description

Technical Field

[0001] This invention relates to the field of battery energy storage system equalization control technology, and in particular to a high-efficiency parallel active equalization method for energy storage batteries based on PWM control. Background Technology

[0002] With the rapid development of electrochemical energy storage, the inherent safety issues of energy storage systems are becoming increasingly prominent. Energy storage battery systems are often composed of several battery modules connected in series and parallel. However, even cells of the same specification and model naturally differ in parameters such as voltage, state of charge, capacity, internal resistance, lifespan, and self-discharge rate. These subtle differences are amplified after being assembled into battery modules, resulting in a high degree of discreteness in the entire battery system. In an energy storage system, the charging and discharging current received by modules connected in series is consistent. However, due to the discreteness, the capacity of each battery module differs, and the charging and discharging capacity of the entire battery system depends on the smallest single cell, thus creating the "weakest link" effect.

[0003] During charging and discharging, the smaller capacity battery module reaches the charge / discharge depth threshold first, limiting the charging and discharging capabilities of other batteries in the battery system. If the battery system cannot be fully charged or discharged for an extended period, it will lose some capacity, causing irreversible damage to the battery system's capacity. This results in inaccurate State of Charge (SOC), decreased depth of discharge, and reduced operating efficiency. Over long periods of operation, the polarization between battery sizes becomes increasingly severe, further reducing the usable capacity of the battery system and leading to issues related to safety and economics. Therefore, battery balancing technology is of paramount importance.

[0004] Battery balancing technology is an effective means of improving the overall performance of battery packs. Battery balancing can be classified into energy-dissipating balancing and non-dissipative balancing based on energy transfer methods. Energy-dissipating balancing typically involves connecting a resistor in parallel across the battery terminals, converting electrical energy into heat energy through resistive discharge. Balancing is based on the cell with the lowest charge level within the battery pack. This method is simple in structure and low in cost, but it poses thermal safety risks and is also a waste of energy. Non-dissipative balancing can be further divided into balancing based on energy storage components such as capacitors and inductors, and balancing based on DC-DC converters. Non-dissipative balancing mainly uses capacitors, inductors, or DC-DC converters to transfer energy between individual cells or between a cell and the entire battery pack. Although its structure is more complex than energy-dissipative balancing, it offers higher energy utilization and more flexible energy transfer.

[0005] In recent years, energy storage systems based on bidirectional active balancing technology have received widespread attention. Bidirectional active balancing technology is a comprehensive balancing strategy mechanism based on factors such as individual cell voltage, individual cell SOC, individual cell SOH, and historical data. This scheme can perform real-time analysis of various battery characteristic data, select individual cells in the battery cluster that require maintenance charging and maintenance discharging, and supplement the low-energy cells with the energy from high-energy cells. Essentially, it performs energy conversion within the battery pack to improve the differences between individual cells. Bidirectional active balancing technology performs active balancing according to the required degree of balancing, which can quickly improve the consistency of individual cell voltage and performance within the battery cluster, while also improving the consistency of battery stack performance, further extending the cycle life of the battery system and enhancing the overall profitability of the energy storage system throughout its life cycle. Balancing does not require tiers and can achieve bidirectional energy transfer between any individual cells within the cluster, across modules, and across packs, without the need for secondary balancing at the module level.

[0006] Existing bidirectional active balancing strategies are primarily applicable to scenarios including a high-SOC battery cell discharging into a redundant battery module, a low-SOC battery cell charging from a redundant battery module, and two cells with inconsistent SOCs simultaneously charging and discharging, using the redundant battery module as an energy relay. However, for energy storage systems with multiple unbalanced cells, existing strategies struggle to achieve simultaneous balancing. Current solutions involve adding balancing circuits. But existing balancing methods pose an overcurrent risk if two or more cells simultaneously discharge into or charge from the redundant module. Furthermore, battery cells inherently exhibit inconsistencies, and the output voltage of a battery cell is mathematically related to its SOC. Therefore, when multiple cells are connected in parallel, differences in output voltage and balancing speed can occur, potentially leading to voltage imbalance and circulating current. Consequently, energy storage manufacturers typically do not allow multiple batteries to be charged and discharged simultaneously for balancing. A single balancing circuit can only simultaneously balance two cells or two modules, resulting in low circuit utilization. Therefore, simply increasing the number of balancing circuits is not the optimal solution.

[0007] Regarding the balancing between clusters, the existing strategy is to first sort the battery strings according to the SOC information of each cluster, and then discharge them from highest to lowest SOC and charge them from lowest to highest SOC. The number of battery strings to be switched is then determined based on the charging and discharging power requirements. However, when the power command exceeds N-1 clusters but is less than N clusters, all N clusters of battery strings are put into operation, thus losing the balancing function. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide a high-efficiency parallel active balancing method for energy storage batteries based on PWM control. This invention solves the problem that the balancing control strategy of existing energy storage battery systems is difficult to simultaneously achieve efficient parallel active balancing of multiple unbalanced SOC cells and inter-cluster balancing, resulting in low utilization of the balancing circuit, limited energy transfer, and insufficient overall system balancing efficiency.

[0009] To achieve the above objectives, the present invention provides the following solution: A high-efficiency parallel active balancing method for energy storage batteries based on PWM control includes: Construct a battery network containing several series and parallel energy storage battery cells; Controllable high-frequency power electronic switches are configured at the electrical connection points of each battery cell and battery string to construct the circuit topology of a bidirectional active balancing energy storage system. Based on the circuit topology of the bidirectional active equalization energy storage system, a dataset of electrical parameter characteristics is collected. Based on the aforementioned electrical parameter feature dataset, a balanced circuit energy interaction model is constructed using a bidirectional converter and a PWM controllable switching mechanism. Based on the aforementioned energy interaction model, PWM charge and discharge control is performed on battery clusters and individual battery cells that are not in operation to obtain inter-cluster balance results; Based on the inter-cluster equalization results, PWM fine-tuning control is applied to the high-frequency power electronic switches between the battery cells and the equalization circuit to obtain intra-cluster parallel equalization results.

[0010] Preferably, the battery network is an N-parallel M-string battery network based on lithium iron phosphate battery cells, where N is the number of clusters in the battery network and M is the number of battery cells in each cluster.

[0011] Preferably, the positive and negative terminals of the battery cell are connected to the bypass common DC bus via a first high-frequency power electronic switching device and a second high-frequency power electronic switching device, respectively.

[0012] Preferably, each battery cluster is connected to the main common DC bus via a third high-frequency power electronic switching device.

[0013] Preferably, the first high-frequency power electronic switching device and the second high-frequency power electronic switching device are MOSFET devices.

[0014] Preferably, the third high-frequency power electronic switch is an IGBT device.

[0015] Preferably, the electrical parameter feature dataset includes: The voltage, state of charge (SOC), and state of health (SOH) of each individual battery cell; the state of charge of each battery string cluster; the output voltage and current of the energy storage system; and external power commands.

[0016] Preferably, the energy interaction model of the equalization circuit includes: Equalization circuit control model and SOC equalization control model; The equalization circuit control model includes a bidirectional forward converter and a battery module. The battery module is used to interact with the individual cells in the battery pack, and the bidirectional forward converter is used to realize bidirectional energy transmission between the individual cells in the battery pack. The SOC equalization control model is used to control the switching of each cluster of battery strings.

[0017] Preferably, the energy interaction model of the equalization circuit further includes: An improved SOC equalization control model; The improved SOC equalization control model is used to control the equalization results of battery clusters and individual battery cells using PWM.

[0018] A high-efficiency parallel active balancing system for energy storage batteries based on PWM control, comprising: The battery network construction module is used to build a battery network containing several series and parallel energy storage battery cells; The circuit topology construction module is used to configure controllable high-frequency power electronic switches at the electrical connection points of each battery cell and battery string in order to construct the circuit topology of a bidirectional active balancing energy storage system. The dataset construction module is used to collect a dataset of electrical parameter characteristics based on the circuit topology of the bidirectional active equalization energy storage system. The equalization circuit energy interaction model construction module is used to construct an equalization circuit energy interaction model based on the electrical parameter feature dataset and using a bidirectional converter and PWM controllable switching mechanism. The charging and discharging control module is used to perform PWM charging and discharging control on battery clusters and individual battery cells that are not in operation based on the road energy interaction model, so as to obtain the inter-cluster equalization result. The equalization module is used to perform PWM fine-tuning control on the high-frequency power electronic switch between the battery cell and the equalization circuit based on the inter-cluster equalization result, so as to obtain the intra-cluster parallel equalization result.

[0019] The present invention discloses the following technical effects: This invention provides a high-efficiency parallel active balancing method for energy storage batteries based on PWM control, comprising: constructing a battery network containing several series-parallel connected energy storage battery cells; configuring controllable high-frequency power electronic switches at the electrical connection points of each battery cell and battery string to construct a circuit topology for a bidirectional active balancing energy storage system; collecting a dataset of electrical parameter characteristics based on the circuit topology of the bidirectional active balancing energy storage system; constructing an energy interaction model for the balancing circuit based on the dataset of electrical parameter characteristics using a bidirectional converter and a PWM controllable switching mechanism; performing PWM charge-discharge control on battery clusters and individual cells that are not in operation based on the energy interaction model to obtain inter-cluster balancing results; and performing refined PWM control on the high-frequency power electronic switches between the battery cells and the balancing circuit based on the inter-cluster balancing results to obtain intra-cluster parallel balancing results. This invention introduces a bidirectional active balancing mechanism based on PWM control, achieving hierarchical parallel active balancing control of energy storage battery systems both between and within clusters. It can dynamically adjust the switching states of individual battery cells and battery clusters according to power commands and SOC distribution, realizing flexible energy distribution under different operating conditions. This not only improves the utilization rate and energy transfer efficiency of the balancing circuit but also significantly improves the SOC consistency among battery cells, enhancing the overall system output power and operational stability, and extending the service life of the energy storage battery. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the 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.

[0021] Figure 1 A flowchart of a high-efficiency parallel active balancing method for energy storage batteries based on PWM control is provided in an embodiment of the present invention. Figure 2 This is a structural diagram of a bidirectional active balancing energy storage system provided in an embodiment of the present invention; Figure 3 A schematic diagram of an existing equilibrium strategy provided in an embodiment of the present invention; Figure 4 A schematic diagram illustrating the improved strategy provided in an embodiment of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1 As shown, this invention provides a high-efficiency parallel active balancing method for energy storage batteries based on PWM control, comprising: Step 100: Construct a battery network containing several series-parallel connected energy storage battery cells; Step 200: Configure controllable high-frequency power electronic switches at the electrical connection points of each battery cell and battery string to construct the circuit topology of the bidirectional active balancing energy storage system. Step 300: Based on the circuit topology of the bidirectional active equalization energy storage system, collect a dataset of electrical parameter characteristics; Step 400: Based on the electrical parameter feature dataset, construct an energy interaction model for the equalization circuit using a bidirectional converter and a PWM controllable switching mechanism; Step 500: Based on the aforementioned energy interaction model, perform PWM charge and discharge control on the battery clusters and individual battery cells that are not in operation to obtain inter-cluster balance results; Step 600: Based on the inter-cluster equalization results, perform PWM fine-tuning control on the high-frequency power electronic switch between the battery cell and the equalization circuit to obtain the intra-cluster parallel equalization results.

[0025] Furthermore, a circuit topology for a bidirectional active balancing energy storage system is established. The circuit topology is a battery network based on N parallel and M string lithium iron phosphate battery cells. The positive and negative terminals of each battery cell are connected to the bypass common DC bus through a high-frequency power electronic switch device. The high-frequency power electronic switches here are all MOSFET devices. At the same time, each battery string cluster is connected to the main common DC bus through a high-frequency power electronic switch device. The high-frequency power electronic switches here are all IGBT devices.

[0026] Specifically, Figure 2The structural topology of a bidirectional active balancing energy storage system is demonstrated. The entire system consists of a 3-parallel, 8-string battery network based on lithium iron phosphate (LFP) cells and a balancing circuit. The positive and negative terminals of each battery cell are connected to a bypass common DC bus via a high-frequency power electronic switch, while each battery string is connected to the main common DC bus via a high-frequency power electronic switch. All high-frequency power electronic switches mentioned here are IGBT devices. The balancing circuit mainly includes two bidirectional forward converters and a redundant battery module. The bidirectional forward converters enable bidirectional energy flow between the high-voltage and low-voltage sides while also providing isolation and voltage transformation. The redundant battery module can interact with the individual cells in the battery pack, allowing cells with higher or lower SOCs to charge and discharge to the redundant module; or it can act as an energy relay to transfer and balance energy from cells with higher SOCs to cells with lower SOCs, ultimately achieving overall balancing of the battery pack.

[0027] Monitor and collect various electrical parameters of the energy storage system, including the voltage, state of charge (SOC), and state of health (SOH) of each individual battery cell, the state of charge of each battery string cluster, the system's output voltage and current, and external power commands.

[0028] Furthermore, the energy interaction model of the equalization circuit includes: Equalization circuit control model and SOC equalization control model; The equalization circuit control model includes a bidirectional forward converter and a battery module. The battery module is used to interact with the individual cells in the battery pack, and the bidirectional forward converter is used to realize bidirectional energy transmission between the individual cells in the battery pack. The SOC equalization control model is used to control the switching of each cluster of battery strings.

[0029] Specifically, a balanced circuit control model is established, which mainly includes a bidirectional forward converter and a redundant battery module. This battery module can interact with the individual cells in the battery pack to enable cells with higher or lower SOC to charge and discharge to the redundant battery module; or it can act as an energy relay to achieve the transfer and balance of electrical energy from cells with higher SOC to cells with lower SOC, ultimately achieving the overall balance of the battery pack.

[0030] A SOC balancing control model for a bidirectional active balancing energy storage system is established. The SOC data of each individual battery cell, the SOC data of each battery cluster, and external power commands are input into the control module. Real-time analysis of various battery characteristic data is performed to select individual cells in the battery cluster that require maintenance charging and maintenance discharging. Active balancing is performed according to the required degree of balancing. The switching of each individual battery cell in the balancing circuit is controlled by controlling the MOSFET switches between the positive and negative terminals of each individual battery cell and the bypass common DC bus. The switching of each battery cluster is also controlled by controlling the IGBTs between each battery cluster and the main common DC bus.

[0031] Furthermore, the energy interaction model of the equalization circuit also includes: An improved SOC equalization control model; The improved SOC equalization control model is used to control the equalization results of battery clusters and individual battery cells using PWM.

[0032] Specifically, the SOC equalization control model is improved by implementing PWM charge and discharge control for unused clusters and cells. When the power command does not exceed the output power of N-1 clusters of battery strings, an equalization strategy of N-choosing N-1 (clusters) and M-choosing M-1 (strings) is adopted. When the power command exceeds the output power of N-1 clusters of battery strings, PWM control is used for the high-frequency power electronic switches of the Nth cluster of battery strings and the Mth battery cell to improve the output voltage and power of the energy storage system. When the power command exceeds the total output power of N clusters of battery strings, all cells in the energy storage system are put into operation, and the entire system operates in full-power mode.

[0033] The SOC balancing control model is improved by implementing PWM control for the high-frequency power switch between the battery cells and the balancing circuit. Each data acquisition delay interval is divided into smaller time scales. When one or more battery cells in different modules within the same battery cluster have unbalanced SOC, the duty cycle of each unbalanced cell is determined by calculating the difference between the excess or insufficient charge and the balancing cell. This allows for PWM control of the power electronic switch of the unbalanced battery cell. PWM charge / discharge control is applicable to scenarios where multiple higher SOC cells charge a single lower SOC cell, a single higher SOC cell charges multiple lower SOC cells, and multiple higher SOC cells charge multiple lower SOC cells, improving the utilization rate of the balancing circuit and further enhancing balancing efficiency.

[0034] Specifically, Figure 3 The diagrams show the existing battery cell balancing strategies, respectively. Figure 3 (a) Only one cell in the same battery string discharges equally to the redundant battery module. Figure 3 (b) Only one cell in the same battery cluster is charged and balanced from redundant battery modules. Figure 3 (c) Two individual cells in different modules within the same battery cluster simultaneously start charging and discharging for equalization.

[0035] For inter-cluster balancing, the switching order of battery strings is first sorted according to the SOC information of each battery string collected by monitoring. Discharge is performed from largest to smallest SOC, and charging is performed from smallest to largest SOC. Then, the number of battery strings to be switched is determined according to the charging and discharging power requirements. However, when the power command exceeds N-1 clusters but is less than N clusters, all N battery strings are put into operation, and the balancing function is lost.

[0036] Figure 4 The diagram illustrates a high-efficiency parallel active balancing method for energy storage batteries based on PWM control proposed in this invention under various operating conditions. Figure 4 (a) represents inter-cluster equilibrium. Figure 4 (b) To enable PWM discharge equalization for three individual cells within the same module simultaneously, Figure 4 (c) Enable PWM charging balancing for three individual cells within the same module simultaneously. Figure 4 (d) This refers to the simultaneous activation of PWM charge / discharge balancing for two individual cells within the same module. Figure 4 (e) Simultaneous PWM charge / discharge balancing is enabled for 6 individual cells across different modules. For inter-cluster balancing, PWM charge / discharge control is applied to unused clusters and unused cells. When the power command does not exceed the output power of N-1 clusters, a balancing strategy of selecting 2 out of 3 clusters or 7 out of 8 cells is adopted. When the power command exceeds the total output power of 3 clusters, all cells in the energy storage system are put into operation, and the entire system operates in full-power mode. When the power command exceeds the output power of 2 clusters, PWM control is applied to the high-frequency power electronic switches of the 3rd cluster and the 8th cell in each cluster to improve the output voltage and power of the energy storage system. At this time, the duty cycle of the PWM signal of the power electronic switch is... It is expressed as the ratio of the excess power to the rated power of a single cluster of cells, i.e.: ; In the formula, The duty cycle of the PWM signal for the power electronic switch. P 总 External power command. P 单 N represents the rated power of a single battery cluster, and N is the number of clusters in the battery network. For balancing within the same battery cluster, each data acquisition delay interval needs to be divided into smaller time scales, and PWM control should be applied to the high-frequency power switches between the battery cells and the balancing circuit. When there are multiple battery cells with unbalanced SOC within the same battery cluster, the difference between the excess or insufficient charge of each cell and the balancing cell is calculated. Then, the duty cycle of the corresponding unbalanced cell is determined based on the ratio of each difference, and the PWM control is applied to the power electronic switches of the unbalanced battery cells. The duty cycle of the PWM signal of the power electronic switch at this time... for: ; In the formula, For the first i The duty cycle of the PWM signal of the power electronic switch of an unbalanced battery cell. SOC i For the first iThe amount of charge in an unbalanced battery cell SOC average is the average charge level of individual cells within the same cluster, and m is the number of individual cells within the same cluster that have not reached the average charge level.

[0037] PWM charge and discharge control can be applied to scenarios where multiple high-SOC cells discharge to redundant modules within the same module or between different modules, multiple low-SOC cells charge from redundant modules, a single high-SOC cell charges multiple low-SOC cells, multiple high-SOC cells charge a single low-SOC cell, and multiple high-SOC cells charge multiple low-SOC cells. It mainly achieves power balancing within the module, improves the utilization rate of the balancing circuit, and further improves the balancing efficiency.

[0038] This embodiment also provides a high-efficiency parallel active balancing system for energy storage batteries based on PWM control, including: The battery network construction module is used to build a battery network containing several series and parallel energy storage battery cells; The circuit topology construction module is used to configure controllable high-frequency power electronic switches at the electrical connection points of each battery cell and battery string in order to construct the circuit topology of a bidirectional active balancing energy storage system. The dataset construction module is used to collect a dataset of electrical parameter characteristics based on the circuit topology of the bidirectional active equalization energy storage system. The equalization circuit energy interaction model construction module is used to construct an equalization circuit energy interaction model based on the electrical parameter feature dataset and using a bidirectional converter and PWM controllable switching mechanism. The charging and discharging control module is used to perform PWM charging and discharging control on battery clusters and individual battery cells that are not in operation based on the road energy interaction model, so as to obtain the inter-cluster equalization result. The equalization module is used to perform PWM fine-tuning control on the high-frequency power electronic switch between the battery cell and the equalization circuit based on the inter-cluster equalization result, so as to obtain the intra-cluster parallel equalization result.

[0039] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0040] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A high-efficiency parallel active balancing method for energy storage batteries based on PWM control, characterized in that, include: Construct a battery network containing several series and parallel energy storage battery cells; Controllable high-frequency power electronic switches are configured at the electrical connection points of each battery cell and battery string to construct the circuit topology of a bidirectional active balancing energy storage system. Based on the circuit topology of the bidirectional active equalization energy storage system, a dataset of electrical parameter characteristics is collected. Based on the aforementioned electrical parameter feature dataset, a balanced circuit energy interaction model is constructed using a bidirectional converter and a PWM controllable switching mechanism. Based on the aforementioned energy interaction model, PWM charge and discharge control is performed on battery clusters and individual battery cells that are not in operation to obtain inter-cluster balance results; Based on the inter-cluster equalization results, PWM fine-tuning control is applied to the high-frequency power electronic switches between the battery cells and the equalization circuit to obtain intra-cluster parallel equalization results.

2. The high-efficiency parallel active balancing method for energy storage batteries based on PWM control according to claim 1, characterized in that, The battery network is an N-parallel M-string battery network based on lithium iron phosphate battery cells, where N is the number of clusters in the battery network and M is the number of battery cells in each cluster.

3. The high-efficiency parallel active balancing method for energy storage batteries based on PWM control according to claim 1, characterized in that, The positive and negative terminals of the battery cell are connected to the bypass common DC bus through a first high-frequency power electronic switching device and a second high-frequency power electronic switching device, respectively.

4. The high-efficiency parallel active balancing method for energy storage batteries based on PWM control according to claim 3, characterized in that, Each battery string is connected to the main common DC bus via a third high-frequency power electronic switching device.

5. A high-efficiency parallel active balancing method for energy storage batteries based on PWM control according to claim 4, characterized in that, The first high-frequency power electronic switching device and the second high-frequency power electronic switching device are MOSFET devices.

6. The high-efficiency parallel active balancing method for energy storage batteries based on PWM control according to claim 4, characterized in that, The third high-frequency power electronic switch is an IGBT device.

7. The high-efficiency parallel active balancing method for energy storage batteries based on PWM control according to claim 1, characterized in that, The electrical parameter feature dataset includes: The voltage, state of charge (SOC), and state of health (SOH) of each individual battery cell; the state of charge of each battery string cluster; the output voltage and current of the energy storage system; and external power commands.

8. The high-efficiency parallel active balancing method for energy storage batteries based on PWM control according to claim 1, characterized in that, The energy interaction model of the equalization circuit includes: Equalization circuit control model and SOC equalization control model; The equalization circuit control model includes a bidirectional forward converter and a battery module. The battery module is used to interact with the individual cells in the battery pack, and the bidirectional forward converter is used to realize bidirectional energy transmission between the individual cells in the battery pack. The SOC equalization control model is used to control the switching of each cluster of battery strings.

9. A high-efficiency parallel active balancing method for energy storage batteries based on PWM control according to claim 1, characterized in that, The energy interaction model of the equalization circuit also includes: An improved SOC equalization control model; The improved SOC equalization control model is used to control the equalization results of battery clusters and individual battery cells using PWM.

10. A high-efficiency parallel active balancing system for energy storage batteries based on PWM control, characterized in that, include: The battery network construction module is used to build a battery network containing several series and parallel energy storage battery cells; The circuit topology construction module is used to configure controllable high-frequency power electronic switches at the electrical connection points of each battery cell and battery string in order to construct the circuit topology of a bidirectional active balancing energy storage system. The dataset construction module is used to collect a dataset of electrical parameter characteristics based on the circuit topology of the bidirectional active equalization energy storage system. The equalization circuit energy interaction model construction module is used to construct an equalization circuit energy interaction model based on the electrical parameter feature dataset and using a bidirectional converter and PWM controllable switching mechanism. The charging and discharging control module is used to perform PWM charging and discharging control on battery clusters and individual battery cells that are not in operation based on the road energy interaction model, so as to obtain the inter-cluster equalization result. The equalization module is used to perform PWM fine-tuning control on the high-frequency power electronic switch between the battery cell and the equalization circuit based on the inter-cluster equalization result, so as to obtain the intra-cluster parallel equalization result.

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