High-power equalization topology circuit based on push-pull transformer and control method

Abstract

The application belongs to the technical field of battery equalization management. A large-power equalization topology circuit and control method based on push-pull transformer are provided, which comprises a battery pack composed of n series-connected battery monomers, a push-pull transformer, a primary side transformer switch group, a discharge side switch group, a charging side switch group and a secondary side output diode. Through the cooperative control of the discharge side and the charging side switch group, the sub-battery pack composed of any monomer or any adjacent monomer can be flexibly connected to the primary side or the secondary side of the push-pull transformer, realizing full-path, bidirectional and high-efficiency energy transfer. Whether to enable the ACAC micro equalization mode is judged according to the voltage standard deviation. If the dispersion is high, the optimal strategy is adaptively selected from a plurality of preset equalization modes in combination with the K-Means clustering algorithm and multi-dimensional clustering characteristics. The application simplifies the circuit structure, and significantly improves the equalization flexibility, efficiency and intelligent level in the large-power scene.

Description

Technical Field

[0001] This invention relates to the field of battery equalization management technology, and in particular to a high-power equalization topology circuit and control method based on a push-pull transformer. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Driven by the rapid development of new energy vehicles and large-scale energy storage systems, lithium-ion battery packs, as the core energy carriers, directly affect the efficiency and safety of the entire system. To improve the overall performance and lifespan of battery packs, battery balancing technology has become an indispensable key component of battery management systems. Active balancing technology has attracted much attention due to its high energy utilization rate, with transformer-based topologies enabling efficient energy transfer between different battery cells. Push-pull converters, as a classic isolated power conversion architecture, are widely used in the power supply field due to their advantages such as bidirectional core excitation, high power density, and good electrical isolation. This provides an important technological foundation for constructing high-performance battery balancing circuits.

[0004] However, existing transformer-based active balancing schemes struggle to support flexible and bidirectional energy dispatching between any individual cell or any adjacent cell sub-packs within a single, compact topology. Many designs either have limited balancing paths, enabling only fixed-mode energy transfer, or introduce excessive passive components or complex control logic to increase flexibility, leading to increased system cost and size, and potentially sacrificing power handling capabilities. Especially in high-power applications, traditional topologies often struggle to balance high efficiency and high integration due to the large number of switching devices and low utilization of magnetic components. Furthermore, the lack of dynamic adaptability to arbitrary sub-pack combinations limits balancing speed and energy transfer accuracy, failing to fully unleash the potential of high-performance battery packs. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-power equalization topology circuit and control method based on a push-pull transformer. The magnetic flux in the transformer core is opposite in direction and equal in amplitude during the positive and negative half-cycles, synthesizing into a complete alternating magnetic flux. This mechanism allows the entire primary winding to be fully utilized on the magnetic circuit, and the energy that can be transferred per unit time is higher than that of a single-ended excitation topology, thus providing the necessary power foundation for outputting large currents.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a high-power equalization topology circuit based on a push-pull transformer.

[0007] A high-power equalization topology circuit based on a push-pull transformer, comprising: A battery pack consisting of individual battery cells connected in series, a push-pull transformer, a primary-side transformer switch group, a discharge-side switch group, a charging-side switch group, and a secondary-side output diode; The primary side of the push-pull transformer is connected to the primary side transformer switch group to receive discharge energy from any single cell or any adjacent cells in the battery pack; the secondary side of the push-pull transformer is connected to the charging side switch group through the secondary side output diode to provide charging energy to any single cell or any adjacent cells in the battery pack. The discharge-side switch group is configured to selectively connect any single cell or any adjacent cell forming a sub-cell group in the battery pack to the primary-side transformer switch group; the charging-side switch group is configured to selectively connect the secondary-side output diode to any single cell or any adjacent cell forming a sub-cell group in the battery pack.

[0008] In one implementation of the first aspect of the present invention, the primary side transformer switch group includes a first switch and a second switch; The center tap of the primary winding of the push-pull transformer is selectively connected to the positive terminal of the battery cell or the positive terminal of the sub-battery group via the discharge side switch group. The upper end of the primary winding is connected to the positive terminal of the battery cell or the negative terminal of the sub-battery group via the first switch and the discharge side switch group. The lower end of the primary winding is connected to the positive terminal of the battery cell or the negative terminal of the sub-battery group via the second switch and the discharge side switch group. The first and second switches are switched on alternately to form alternating magnetic fluxes with opposite directions and equal amplitudes on the primary side of the push-pull transformer.

[0009] As a further limitation of the first aspect of the invention, the discharge-side switch group includes a connection with the first... individual battery cells The corresponding first, second, third, and fourth electronic switches; The first and second discharge switches are connected in series at the center tap of the primary winding of the push-pull transformer. individual battery cells Between the positive poles; The first terminal of the third and fourth electronic switches connected in series is respectively connected to the... individual battery cells The negative electrode and the first individual battery cells The positive terminal is connected, and the second terminal of the third and fourth discharge switches connected in series is connected to the first and second switches respectively.

[0010] As a further limitation of the first aspect of the present invention, the charging side switch group includes a first charging sub-switch, a second charging sub-switch, a third charging sub-switch and a fourth charging sub-switch corresponding to the i-th battery cell Bi, and the secondary side output diode includes a first diode and a second diode. The upper end of the secondary winding of the push-pull transformer is connected to the anode of the first diode, and the lower end of the secondary winding of the push-pull transformer is connected to the anode of the second diode. The cathodes of the first diode and the second diode are connected to the common charging node. The first terminal of the first charging electronic switch connected in series with the second charging electronic switch is connected to the... individual battery cells The positive terminal is connected, and the second terminal of the first charging electronic switch and the second charging electronic switch connected in series is connected to the common charging node; The first terminal of the third and fourth charging electronic switches connected in series is respectively connected to the first... individual battery cells The negative electrode and the first individual battery cells The positive terminal is connected, and the second terminal of the third and fourth charging electronic switches connected in series is connected to the center tap of the secondary winding of the push-pull transformer.

[0011] In one implementation of the first aspect of the present invention, the balanced topology supports five balanced modes, namely: P2C mode where the total battery pack charges individual cells, C2P mode where individual cells charge the total battery pack, ACAC mode where any individual cells balance each other, Sub2P mode where sub-battery packs charge the total battery pack, and P2Sub mode where the total battery pack charges sub-battery packs.

[0012] As a further limitation of the first aspect of the present invention, at the end of any equalization mode, the switching control state remains unchanged until the energy in the push-pull transformer is completely exhausted, so that the circuit enters a static state, thereby ensuring that the entire equalizer operates in the DCM (Discontinuous Conduction Mode) intermittent mode.

[0013] Secondly, the present invention provides a high-power equalization method based on a push-pull transformer.

[0014] A high-power equalization method based on a push-pull transformer, utilizing the high-power equalization topology circuit based on a push-pull transformer of the first aspect of this invention, includes the following process: Collect voltage data for all individual cells in the battery pack; Calculate the standard deviation of the collected voltage data and determine whether the standard deviation is less than a preset threshold; if yes, execute the ACAC mode for mutual balancing between any individual units; if no, proceed to the next step. The K-Means clustering algorithm is applied to the voltage data. The optimal number of clusters K is determined by the elbow rule and the silhouette coefficient, and all battery cells are divided into K clusters. The characteristics of each cluster are analyzed, including cluster size, mean voltage within the cluster, standard deviation of voltage within the cluster, and physical proximity score of individual cells within the cluster. Based on the characteristics of each cluster and the number of clusters K, the optimal equilibrium mode is determined from P2C mode, C2P mode, ACAC mode, Sub2P mode and P2Sub mode and then executed.

[0015] In one implementation of the second aspect of the present invention, when the number of clusters K is 1, the voltage is uniformly distributed and the ACAC mode is adopted.

[0016] In one implementation of the second aspect of the present invention, when the number of clusters K is 2, it is determined whether there is a main cluster whose size accounts for more than 60%; if there is a main cluster, then based on the voltage level and size of the non-main clusters relative to the main cluster, a decision is made to execute the P2C mode, C2P mode, Sub2P mode or P2Sub mode. If two clusters are of similar size and are adjacent, then subgroup equilibrium is used.

[0017] In one implementation of the second aspect of the present invention, when the number of clusters K is greater than or equal to 3, it is determined whether there is a major cluster with a significant size; if there is, the equilibrium mode is decided based on the characteristics of the remaining high-voltage clusters or low-voltage clusters; if there is not, it is further determined whether there are multiple sub-clusters with adjacent physical locations; if so, the inter-subgroup equilibrium is performed, otherwise the ACAC mode is performed.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention effectively solves the problem of flexible, efficient, and bidirectional energy dispatching between any single cell or adjacent sub-cell pack within a single compact structure by constructing a high-power balancing topology circuit based on a push-pull transformer. This topology uses a shared push-pull transformer as the core of energy transfer, and with the coordinated control of the primary-side transformer switching group, the discharge-side switching group, and the charging-side switching group, the discharge energy from any selected cell or adjacent sub-cell pack can be injected into the transformer on the primary side and precisely fed back to another arbitrary target cell or sub-cell pack via the secondary-side output diode. This structure avoids the drawbacks of traditional solutions that require multiple independent magnetic components or redundant switching devices to support multi-path balancing, significantly simplifying the hardware architecture and improving core utilization and power density. Simultaneously, the push-pull topology itself possesses excellent electrical isolation and high conversion efficiency characteristics. Combined with a precise switching selection mechanism, it can achieve low-loss, high-reliability energy transfer under high-power conditions, thus balancing system integration, cost control, and balancing performance, meeting the core requirements of high-performance battery packs for fast, flexible, and high-power balancing.

[0019] This invention proposes a high-power equalization method based on a push-pull transformer. Leveraging the hardware flexibility of the aforementioned topology, it further achieves adaptive and efficient equalization in complex and inconsistent scenarios through an intelligent mode decision-making mechanism. First, this invention determines the overall dispersion of the battery pack based on the voltage standard deviation. If the consistency is good, the efficient ACAC mode is directly activated for fine-tuning; if the dispersion is severe, the K-Means clustering algorithm is introduced, combining the elbow rule and silhouette coefficient to automatically determine the optimal number of clusters, ensuring scientific and reasonable grouping. More importantly, this invention not only considers the voltage mean but also comprehensively evaluates multi-dimensional features such as cluster size, internal consistency, and physical adjacency score, thereby intelligently selecting the strategy most suitable for the current state among various equalization modes such as P2C, C2P, Sub2P, P2Sub, and ACAC. For example, when a high-voltage cluster consists of adjacent cells, the Sub2P mode can be activated to improve power efficiency by utilizing the overall discharge of the sub-cell pack; conversely, the same applies. This data-driven, multimodal collaborative control logic fully leverages the full-path scheduling capability of the topology circuit of this invention, significantly reducing energy loss and switching stress while ensuring equalization speed, ultimately achieving more accurate, efficient, and robust high-power battery equalization.

[0020] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0022] Figure 1 A schematic diagram of an equalization topology circuit provided as an exemplary embodiment of the present invention; Figure 2 A schematic diagram of battery pack discharge provided as an exemplary embodiment of the present invention; Figure 3 A schematic diagram of a battery cell charging as provided in an exemplary embodiment of the present invention; Figure 4 A schematic diagram of a single battery cell discharge provided as an exemplary embodiment of the present invention; Figure 5 A schematic diagram of battery pack charging is provided as an exemplary embodiment of the present invention; Figure 6 A schematic diagram of the discharge of a sub-battery pack is provided as an exemplary embodiment of the present invention; Figure 7 A schematic diagram of a sub-battery pack charging is provided as an exemplary embodiment of the present invention; Figure 8 A schematic diagram of the K-Means algorithm flow provided as an exemplary embodiment of the present invention; Figure 9 A diagram illustrating the effect of a P2C equalization experiment provided as an exemplary embodiment of the present invention; Figure 10 A C2P equalization experiment effect diagram provided as an exemplary embodiment of the present invention; Figure 11 A diagram illustrating the effect of an ACAC equalization experiment provided as an exemplary embodiment of the present invention; Figure 12 A diagram illustrating the effect of a Sub2P equalization experiment provided as an exemplary embodiment of the present invention; Figure 13 The diagram shows the effect of a P2Sub equalization experiment provided as an exemplary embodiment of the present invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] This implementation proposes a high-power balancing topology circuit based on a push-pull transformer. The push-pull transformer achieves balanced energy transfer, effectively overcoming the low excitation efficiency problem of traditional single-ended transformers. This structure alternates conduction during the positive and negative half-cycles, enabling bidirectional symmetrical magnetization of the transformer core, significantly improving core utilization and energy conversion efficiency. This not only increases output power but also provides the system with a larger balancing current capability, thus achieving a faster and more efficient battery balancing process. The high-power balancing topology circuit achieves full-path balancing of the battery pack and supports balancing of any number of adjacent battery cells forming sub-battery packs, providing more options for balancing strategies and improving the flexibility of the battery management system. To select the most suitable balancing path and further improve balancing efficiency, this patent proposes a balancing strategy based on the K-Means algorithm. This strategy classifies the battery voltage distribution and calculates the appropriate balancing path, thereby improving balancing efficiency.

[0026] The equalization topology based on push-pull transformers in this implementation is as follows: Figure 1 As shown. Wherein, B1, B2, ... B n-1 B n These are individual battery cells in a battery pack. n This is the individual item number. Q 11 (i.e., the first discharge switch of battery cell B1), Q 12 (i.e., the second discharge switch of battery cell B1), Q 15 (i.e., the third electronic switch of battery cell B1), Q 16 (i.e., the fourth discharge switch of battery cell B1)...Q n1 (i.e., battery cell B) n First electronic switch), Q n2 (i.e., battery cell B) n The second electronic switch), Q n5 (i.e., battery cell B) n The third electronic switch), Q n6 This indicates the switch group on the discharge side (i.e., battery cell B). n The fourth electronic switch), Q 13 (i.e., the first charging electronic switch of battery cell B1), Q 14 (i.e., the second charging electronic switch of battery cell B1), Q 17 (i.e., the third charging electronic switch of battery cell B1), Q 18 (i.e., the fourth charging electronic switch of battery cell B1)...Q n3 (i.e., battery cell B) n First charging electronic switch), Q n4 (i.e., battery cell B) n The second charging electronic switch), Q n7(i.e., battery cell B) n The third charging electronic switch), Q n8 (i.e., battery cell B) n The fourth charging electronic switch) represents the switch group on the charging side, Q. a (i.e., the first switch), Q b (i.e., the second switch) represents the primary-side transformer switch group, used to achieve primary-side push-pull input. D1 (i.e., the first diode) and D2 (i.e., the second diode) are the secondary-side output diodes of the transformer, used to achieve secondary-side push-pull output. In conventional designs, analog front-end chips are often used to acquire battery voltage, and a microcontroller generates pulse width modulation signals to control the on and off states of the IGBTs.

[0027] To better illustrate the work process, the following assumptions are made: 1) On the primary side, the current flowing out of the battery is positive, and the current flowing into the battery on the secondary side is positive. When the voltage on the primary side of the transformer is positive at the top and negative at the bottom, it is positive; when the voltage on the secondary side is negative at the top and positive at the bottom, it is positive. 2) When the primary current flows into the transformer's corresponding terminal, it is in the positive reference direction and the magnetic flux is positive; when the current flows out of the transformer's corresponding terminal, it is in the negative reference direction and the magnetic flux is negative. 3) When the current flows out of the transformer's secondary side terminal, it is in the positive reference direction and the magnetic flux is positive; when the current flows into the transformer's secondary side terminal, it is in the negative reference direction and the magnetic flux is negative. 4) The main control unit generates a pair of complementary PWM (Pulse Width Modulation), namely PWM+ and PWM-, where PWM+ controls the primary side discharge switch group and PWM- controls the secondary side charging switch group.

[0028] (A) Balance between battery pack and individual battery cells (P2C).

[0029] The battery pack discharge process is as follows Figure 2 As shown, the working process of the equalizer is analyzed using an equalization topology composed of four batteries as an example. The red path represents the discharge current path and the blue path represents the charging current path.

[0030] Write the current-voltage equations based on Kirchhoff's laws: (1); (2); in, Indicates the discharge current. Indicates the battery pack voltage. This represents the equivalent resistance of the primary circuit. L 11 and L 12This represents the inductance coefficients of the upper and lower half of the primary winding. t Indicates the equilibrium time. V L1 This represents the primary winding voltage. As can be seen from formulas (1) and (2), the current gradually increases and the discharge voltage gradually decreases during the battery pack discharge process.

[0031] The charging process of a single battery cell is as follows Figure 3 As shown, the equations can be written according to Kirchhoff's laws: (3); (4); in, Indicates the charging current. Indicates the voltage of a single battery cell. This represents the equivalent resistance of the secondary circuit. L 21 and L 22 This represents the inductance coefficient of the upper and lower halves of the secondary winding. i f This represents the initial current mapped from the primary side to the secondary side. V L2 This represents the secondary side voltage. As can be seen from formulas (3) and (4), the charging current gradually decreases from its maximum value, and the charging voltage gradually decreases from its maximum value until the transformer is completely demagnetized.

[0032] At the last moment, maintain the same switching control state as the previous moment and wait for the transformer energy to be completely exhausted. At this time, the circuit enters a static state, ensuring that the equalizer is always in the DCM intermittent working mode.

[0033] (B) Balance between individual cells and battery pack (C2P).

[0034] Battery cell discharge such as Figure 4 As shown, the equations can be written according to Kirchhoff's laws: (5); (6); L p1 Let be the inductance coefficient of the primary winding. From formulas (5) and (6), it can be seen that when a single battery cell discharges to the primary side of the transformer, the discharge current gradually increases and the voltage gradually decreases.

[0035] The battery pack charging process is as follows Figure 5 As shown, the equations can be written according to Kirchhoff's laws: (7); (8); As can be seen from formulas (7) and (8), during the battery pack charging process, the charging current and charging voltage gradually decrease from their maximum values.

[0036] At the last moment, maintain the same switching control state as the previous moment and wait for the transformer energy to be completely exhausted. At this time, the circuit enters a static state, ensuring that the equalizer is always in the DCM intermittent working mode.

[0037] (C) Equilibrium between any individual units (ACAC).

[0038] Battery cell discharge such as Figure 4 As shown, equations (5) and (6) are written according to Kirchhoff's laws. From the formulas, it can be seen that when a battery cell discharges to the primary side of the transformer, the discharge current gradually increases and the voltage gradually decreases.

[0039] Battery cell charging, such as Figure 3 As shown, equations (3) and (4) are written according to Kirchhoff's laws. From the formulas, it can be seen that the charging current of a single battery cell gradually decreases from its maximum value, while the charging voltage gradually decreases from its maximum value until the transformer is completely demagnetized, finally entering DCM mode.

[0040] (D) Balancing between sub-cell packs and the main cell pack (Sub2P).

[0041] The equalization process of Sub2P is similar to that of C2P. Taking a sub-cell pack consisting of three individual cells (battery 1, battery 2, and battery 3) as an example, the discharge process of the sub-cell pack is as follows: Figure 6 As shown. Based on Kirchhoff's laws, the equation for the discharge process is written as follows: (9); (10); in, This represents the voltage of the sub-cell pack. As can be seen from formulas (9) and (10), when a single cell discharges to the primary side of the transformer, the discharge current gradually increases and the voltage gradually decreases.

[0042] The battery pack charging process is as follows Figure 5 As shown, the equations are written according to Kirchhoff's laws as shown in formulas (7) and (8). From the formulas, it can be seen that during the battery pack charging process, the charging current and charging voltage gradually decrease from their maximum values. At the final moment, the same switching control state as the previous moment is maintained, waiting for the transformer energy to be completely depleted. At this time, the circuit enters a static state, ensuring that the equalizer is always in the DCM intermittent working mode.

[0043] (E) Balancing between the main battery pack and sub-battery packs (P2Sub).

[0044] P2Sub balancing mode is similar to P2C, and the overall battery pack discharge process is as follows: Figure 2 As shown. Based on Kirchhoff's laws, the equations are written as shown in equations (3) and (4). It can be seen from the equations that the charging current gradually decreases from its maximum value, and at the same time, the charging voltage gradually decreases from its maximum value until the transformer is completely demagnetized.

[0045] The demonstration will be conducted using a battery pack consisting of two individual cells, battery 1 and battery 2. Figure 7 As shown, the equations can be written according to Kirchhoff's laws: (11); (12); As can be seen from formulas (11) and (12), the charging current gradually decreases from its maximum value, and the charging voltage gradually decreases from its maximum value until the transformer is completely demagnetized.

[0046] At the last moment, maintain the same switching control state as the previous moment and wait for the transformer energy to be completely exhausted. At this time, the circuit enters a static state, ensuring that the equalizer is always in the DCM intermittent working mode.

[0047] The intelligent battery balancing path classification system based on K-means clustering algorithm achieves adaptive decision-making for balancing strategies in the equalizer through voltage distribution feature analysis. The system workflow diagram is as follows: Figure 8 As shown. First, the system analyzes the voltage distribution characteristics of the battery pack, including calculating statistical indicators such as the mean, standard deviation, range, and interquartile range of the voltage, to gain a preliminary understanding of the overall concentration and dispersion of the voltage. When the voltage standard deviation is less than 10mV, the system directly determines it to be in ACAC mode, because in this case, the voltages of all batteries are very close, and no complex balancing strategy is needed.

[0048] If the voltage distribution is relatively dispersed, the system will enter the K-means clustering stage, automatically determining the optimal number of clusters K through the elbow rule and silhouette coefficient. Usually, 2-4 clusters are considered to adapt to different complexities.

[0049] Next, K-means clustering is performed to divide the batteries into several groups based on voltage similarity, and the characteristics of each cluster are analyzed, including cluster size, mean voltage, standard deviation, and adjacency score.

[0050] Classification decisions are based on clustering results: If there is only one cluster, it indicates that the voltage is uniformly distributed, and ACAC is adopted; If there are two clusters, check the proportion of the main cluster. When the main cluster exceeds 60%, further analyze the voltage relationship between the other cluster and the main cluster. High-voltage small clusters trigger C2P mode, high-voltage adjacent small clusters trigger Sub2P mode, low-voltage small clusters trigger P2C mode, and low-voltage adjacent small clusters trigger P2Sub mode. If the two clusters are of similar size and adjacent, subgroup balancing is used. Here, a high-voltage small cluster means that some cells have high voltage, most cells have low voltage, most cells with low voltage form a large cluster, and the few high-voltage cells form a small cluster. A high-voltage adjacent small cluster means that some cells have high voltage but are all adjacent cells and can form a sub-cell group to participate in balancing. A low-voltage small cluster means that some cells have low voltage but most cells have high voltage. A low-voltage adjacent small cluster means that some cells have low voltage but are all adjacent cells and can form a sub-cell group.

[0051] When there are 3 or more clusters, the system will first check whether there is a clear main cluster and select the appropriate balancing mode according to the high and low voltage clusters. If there is no clear main cluster but there are multiple adjacent subgroups, the subgroup balancing mode will be used. Otherwise, the ACAC mode will be used by default.

[0052] The entire process comprehensively considers the numerical similarity of voltage, the physical proximity of batteries, and the scale of the cluster, realizing a complete classification link from data-driven to intelligent decision-making.

[0053] To better illustrate the effect of the topology circuit of this invention, a balancing experimental platform consisting of 12 lithium battery cells connected in series was built. Balancing experiments were conducted using P2C, C2P, ACAC, Sub2P, and P2Sub methods. The experimental results are as follows: Figures 9 to 13 As shown.

[0054] In P2C experiments, such as Figure 9 As shown, the initial highest single-cell voltage was 3.286V, the lowest single-cell voltage was 2.976V, and the average voltage was 3.2315V. The voltage eventually equalized to approximately 3.2V, with the voltage difference between the highest and lowest single-cell voltages within 10mV. The total equalization time was 14 minutes.

[0055] In C2P experiments, such as Figure 10 As shown in the figure. Initially, the highest single-cell voltage was 3.274V, the lowest single-cell voltage was 3.106V, and the average voltage was 3.152V. The voltage eventually equalized to around 3.1V, with the voltage difference between the highest and lowest single-cell voltages within 10mV. The total equalization time was 28 minutes.

[0056] In the ACAC experiment, such as Figure 11As shown in the figure. Initially, the highest single-cell voltage was 3.286V, the lowest single-cell voltage was 3.067V, and the average voltage was 3.247V. The voltage eventually equalized to approximately 3.2V, with the voltage difference between the highest and lowest single-cell voltages within 10mV. The total equalization time was 55 minutes.

[0057] In the Sub2P experiment, such as Figure 12 As shown in the figure. Initially, the highest single-cell voltage was 3.352V, the lowest single-cell voltage was 3.298V, and the average voltage was 3.314V. The voltage eventually equalized to around 3.3V, with the voltage difference between the highest and lowest single-cell voltages within 10mV. The total equalization time was 5 minutes.

[0058] In the P2Sub experiment, such as Figure 13 As shown in the figure. Initially, the highest single-cell voltage was 3.287V, the lowest single-cell voltage was 3.122V, and the average voltage was 3.217V. The voltage eventually equalized to around 3.2V, with the voltage difference between the highest and lowest single-cell voltages within 10mV. The total equalization time was 16 minutes.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-power equalization topology circuit based on a push-pull transformer, characterized in that, Including by A battery pack consisting of individual battery cells connected in series, a push-pull transformer, a primary-side transformer switch group, a discharge-side switch group, a charging-side switch group, and a secondary-side output diode; The primary side of the push-pull transformer is connected to the primary side transformer switch group to receive discharge energy from any single cell or any adjacent cells in the battery pack; the secondary side of the push-pull transformer is connected to the charging side switch group through the secondary side output diode to provide charging energy to any single cell or any adjacent cells in the battery pack. The primary transformer switchgear includes a first switch and a second switch; The center tap of the primary winding of the push-pull transformer is selectively connected to the positive terminal of the battery cell or the positive terminal of the sub-battery group via the discharge side switch group. The upper end of the primary winding is connected to the positive terminal of the battery cell or the negative terminal of the sub-battery group via the first switch and the discharge side switch group. The lower end of the primary winding is connected to the positive terminal of the battery cell or the negative terminal of the sub-battery group via the second switch and the discharge side switch group. The discharge-side switch group is configured to selectively connect any single cell or any adjacent cell in the battery pack to the primary-side transformer switch group; the charging-side switch group is configured to selectively connect the secondary-side output diode to any single cell or any adjacent cell in the battery pack. The discharge-side switch group includes the first individual battery cells The corresponding first, second, third, and fourth electronic discharge switches; the first and second electronic discharge switches are connected in series at the center tap of the primary winding of the push-pull transformer and the fourth electronic discharge switch. individual battery cells Between the positive terminals; the first terminals of the third and fourth discharge switches connected in series are respectively connected to the first... individual battery cells The negative electrode and the first individual battery cells The positive terminal is connected, and the second terminal of the third and fourth discharge switches connected in series is connected to the first and second switches respectively. The charging side switch group includes the first individual battery cells The corresponding first charging electronic switch, second charging electronic switch, third charging electronic switch and fourth charging electronic switch, the secondary side output diode includes the first diode and the second diode; The K-Means clustering algorithm is applied to the voltage data. The optimal number of clusters K is determined by the elbow rule and the silhouette coefficient, and all battery cells are divided into K clusters. The upper end of the secondary winding of the push-pull transformer is connected to the anode of the first diode, and the lower end of the secondary winding of the push-pull transformer is connected to the anode of the second diode. The cathodes of the first diode and the second diode are connected to the common charging node. The first terminal of the first charging electronic switch connected in series with the second charging electronic switch is connected to the... individual battery cells The positive terminal is connected, and the second terminal of the first charging electronic switch and the second charging electronic switch connected in series is connected to the charging common node; The first terminal of the third and fourth charging electronic switches connected in series is respectively connected to the first... individual battery cells The negative electrode and the first individual battery cells The positive terminal is connected, and the second terminal of the third and fourth charging electronic switches connected in series is connected to the center tap of the secondary winding of the push-pull transformer. The characteristics of each cluster are analyzed, including cluster size, mean voltage within the cluster, standard deviation of voltage within the cluster, and physical proximity score of individual cells within the cluster. Based on the characteristics of each cluster and the number of clusters K, the optimal equilibrium mode is determined and executed from P2C mode, C2P mode, ACAC mode, Sub2P mode and P2Sub mode. The first and second switches are switched on alternately to form alternating magnetic fluxes with opposite directions and equal amplitudes on the primary side of the push-pull transformer.

2. The high-power equalization topology circuit based on a push-pull transformer as described in claim 1, characterized in that, The balanced topology supports five balancing modes: P2C mode (charging individual cells from the total battery pack), C2P mode (charging the total battery pack from individual cells), ACAC mode (balancing between any individual cells), Sub2P mode (charging the total battery pack from sub-cells), and P2Sub mode (charging the sub-cells from the total battery pack).

3. The high-power equalization topology circuit based on a push-pull transformer as described in claim 2, characterized in that, At the end of any equalization mode, the switching control state remains unchanged until the energy in the push-pull transformer is completely depleted, causing the circuit to enter a static state, so as to ensure that the entire equalizer operates in DCM intermittent mode.

4. A high-power equalization method based on a push-pull transformer, characterized in that, The high-power equalization topology circuit based on a push-pull transformer as described in any one of claims 1-3 includes the following process: Collect voltage data for all individual cells in the battery pack; Calculate the standard deviation of the collected voltage data and determine whether the standard deviation is less than a preset threshold; if yes, execute the ACAC mode for mutual balancing between any individual units; if no, proceed to the next step. The K-Means clustering algorithm is applied to the voltage data. The optimal number of clusters K is determined by the elbow rule and the silhouette coefficient, and all battery cells are divided into K clusters. The characteristics of each cluster are analyzed, including cluster size, mean voltage within the cluster, standard deviation of voltage within the cluster, and physical proximity score of individual cells within the cluster. Based on the characteristics of each cluster and the number of clusters K, the optimal equilibrium mode is determined from P2C mode, C2P mode, ACAC mode, Sub2P mode and P2Sub mode and then executed.

5. The high-power equalization method based on a push-pull transformer as described in claim 4, characterized in that, When the number of clusters K is 1, the voltage is uniformly distributed, and the ACAC mode is adopted.

6. The high-power equalization method based on a push-pull transformer as described in claim 4, characterized in that, When the number of clusters K is 2, it is determined whether there is a main cluster whose size accounts for more than 60%; if there is a main cluster, the decision to execute P2C mode, C2P mode, Sub2P mode or P2Sub mode is made based on the voltage level and size of the non-main clusters relative to the main cluster. If two clusters are of similar size and are adjacent, then inter-cluster balance is used.

7. The high-power equalization method based on a push-pull transformer as described in claim 4, characterized in that, When the number of clusters K is greater than or equal to 3, determine whether there is a major cluster with a significant size. If it exists, decide on the equilibrium mode based on the characteristics of the remaining high-voltage or low-voltage clusters. If it does not exist, further determine whether there are multiple physically adjacent sub-clusters. If they exist, perform inter-group equilibrium; otherwise, perform ACAC mode.

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