Sodium-ion battery charge-discharge equalization control system for railway passenger cars

Abstract

The present application relates to the technical field of electric control and energy storage management of rail vehicles, in particular to a sodium-ion battery charge-discharge equalization control system for railway passenger cars, which comprises a control main unit connected with a main power supply network and a passenger car equipment load, a main circuit relay, an energy storage monomer matrix, a magnetic chain coupling type transient energy redirection network, a super backup capacitor element, a high-frequency hardware comparator detection array, a control central storage chip and a reverse flow blocking gating diode matrix; a state anchoring module extracts the lowest voltage monomer as a target node and controls access during the self-checking period; the monomer voltage is dynamically collected during charging, any monomer reaches the highest safety threshold, and the residual electric energy is unidirectionally injected into the target node within the relay delay window; during discharging, the total pressure is cut off, and the reactive rebound energy on the load side is stored in the super backup capacitor element, so as to realize safe disconnection, low-voltage monomer compensation and power-off log keeping.

Description

Technical Field

[0001] This invention relates to the field of electrical control and energy storage management technology for railway vehicles, specifically a sodium-ion battery charge-discharge equalization control system for railway passenger cars. Background Technology

[0002] As an important component of the auxiliary power supply system for railway passenger cars, the backup power supply link typically undertakes the tasks of platform power replenishment, standby operation, and emergency power supply after abnormal disconnection from the main network. To ensure the power supply safety and availability of sodium-ion battery packs under the above operating conditions, it is usually necessary to control the charging access, overvoltage disconnection, discharge cutoff, and consistency status between individual energy storage cells, so as to avoid problems such as overcharging and over-discharging of individual cells and a decrease in the overall capacity utilization rate of the pack.

[0003] However, when controlling the charging and discharging of sodium-ion battery packs in railway passenger cars, existing solutions mainly rely on overall total voltage control or conventional individual cell threshold protection. Although these solutions can achieve basic connection and disconnection functions, the parasitic inductance energy and load-side rebound energy in the circuit are often directly dissipated or converted into contact arcs at the moment the relay disconnects, making it difficult to simultaneously meet the requirements of individual cell equalization compensation and control maintenance. Furthermore, when there are voltage differences between energy storage cells, using fixed equalization or simple threshold disconnection methods can easily lead to insufficient compensation for low-voltage cells, frequent disconnection of cells that reach the upper limit first, and difficulty in completely saving the status information at the moment of power failure. This affects the safety of the railway passenger car backup power supply system, the lifespan of the relays, and the overall operational stability of the battery pack. Summary of the Invention

[0004] The purpose of this invention is to provide a charge-discharge equalization control system for sodium-ion batteries in railway passenger cars, addressing the following technical problems: Existing charge-discharge control technologies for railway passenger cars have significant shortcomings in addressing the direct dissipation or conversion of parasitic inductance and load-side rebound energy during relay disconnection into contact arcs, insufficient compensation for low-voltage cells due to simple threshold cutoff, and difficulty in fully preserving state information during power outages. Therefore, there is an urgent need for a charge-discharge equalization control system for sodium-ion batteries in railway passenger cars that can redirect residual energy from the circuit breaker transient for targeted compensation of low-voltage cells and capture load reactive rebound energy to simultaneously achieve contact protection and control log retention. This invention can be achieved through the following technical solutions:

[0005] A sodium-ion battery charge / discharge equalization control system for railway passenger cars includes a main control unit connecting the main power grid and the passenger car equipment load. This main control unit connects a main circuit relay, an energy storage cell matrix, a magnetic flux-coupled transient energy redirection network, a super-backup capacitor element, a high-frequency hardware comparator detection array, a control central storage chip, and a reverse-current blocking gating diode matrix. The main circuit relay includes a control coil and mechanical moving and stationary contacts. The magnetic flux-coupled transient energy redirection network is connected across the two ends of the main circuit relay, and its output is controlled to be connected to the energy storage cell matrix. The main control unit includes:

[0006] State anchoring module: During the power supply self-test period, it acquires the initial voltage data of each energy storage cell, marks the cell with the lowest voltage as a specific target node, and controls the main circuit relay to close to connect to the main power grid when the data meets the preset access voltage range conditions;

[0007] Dynamic evolution monitoring module: continuously collects voltage data of each energy storage cell during charging to construct a real-time voltage data set;

[0008] Residual trigger module: Determines the comparison status of the set with the preset highest safety threshold, generates a command to be sent to the control coil to adjust the main circuit relay to maintain connection or disconnect; During the delayed action window period of the disconnect command cutting off the main power grid, controls the magnetic flux coupling transient energy redirection network to open the physical conduction path to the target node, and injects the residual inductance energy at the moment of disconnection into the target node unidirectionally for compensation.

[0009] Discharge closed-loop module: During discharge, compare the total voltage of the entire system with the preset cutoff discharge threshold. At the instant the power supply network connected to the bus equipment load is cut off, capture the reactive rebound energy data of the load end and transfer it to the super backup capacitor element for storage.

[0010] Optionally, the flux-coupled transient energy redirection network includes an inductive reactance absorbing buffer branch and a multiplexed solid-state switch matrix;

[0011] The inductive reactance absorbing buffer branch is connected in parallel to the two ends of the main circuit relay;

[0012] The current input terminal of the multiplexed solid-state switch matrix is ​​connected to the inductive reactance absorbing buffer branch, and the branch output terminals of the multiplexed solid-state switch matrix are electrically connected in parallel to the two pole pins of each of the energy storage cells.

[0013] The residual triggering module establishes the directional matching physical conduction path by manipulating a specific switch channel in the multiplexed solid-state switch matrix corresponding to the target node.

[0014] Optionally, the process of the state anchoring module extracting the minimum voltage cell and marking the minimum voltage cell as the target node includes:

[0015] Extract the steady-state static voltage value of each energy storage cell in the energy storage cell matrix within a preset monitoring time period;

[0016] Retrieve the preset voltage consistency tolerance threshold range, calculate the maximum absolute difference between each of the static voltage steady-state values, and configure it as the full matrix limit deviation parameter;

[0017] If the full matrix limit deviation parameter is less than the voltage consistency tolerance threshold range, then the associated energy storage cell with the smallest actual value is selected from each of the static voltage steady-state values, and the associated energy storage cell is established as the smallest voltage cell and marked as the target node accordingly.

[0018] If the full matrix limit deviation parameter is greater than or equal to the voltage consistency tolerance threshold range, a matrix unit instability alarm signal is issued, and the main circuit relay is kept in the disconnection suppression state to prevent power supply.

[0019] Optionally, the process by which the residual triggering module determines the comparison status between the real-time voltage data set and a preset maximum safety threshold to generate a switching command includes:

[0020] If all real-time voltage data in the real-time voltage data set are less than the maximum safety threshold, then the keep-connection command is generated to maintain the excitation current input to the main circuit relay control coil without decay, and the continuous power loading operation of connecting to the main power grid is executed.

[0021] If at least one real-time voltage data point in the real-time voltage data set is greater than or equal to the highest safety threshold, then the circuit breaker command is generated to remove the excitation current for the control coil, and the energy transient transfer equalization process is activated for processing.

[0022] Optionally, the process of activating the energy transient transfer equalization procedure includes:

[0023] Step 1: Record the pre-calibrated mechanical disconnection delay time constant between the issuance of the circuit breaker command and the physical separation of the mechanical moving contact from the stationary contact of the main circuit relay, and determine that the mechanical disconnection delay time constant is the delay action window period.

[0024] Step 2: During the delayed action window, extract the parasitic inductance parameter data of the bus and the slope parameter of the sudden change in the instantaneous current of the bus, and calculate the peak value data of the induced electromotive force generated by the circuit breaker.

[0025] Step 3: Control the switching action of the multiplexed solid-state switch matrix to close the physical conduction path of the target node. The peak value data of the induced electromotive force is reconstructed into transient current pulse data through the waveform trimming of the inductive reactance absorbing buffer branch. The transient current pulse data is applied to the target node in the lowest voltage state along the physical conduction path to perform forced current injection compensation.

[0026] Step 4: Combining the peak-shaving effect of induced energy during the waveform trimming and reconstruction dissipation process, a non-arc-induced degraded disconnection response is completed at the contact separation surface of the main circuit relay.

[0027] Optionally, the process by which the dynamic evolution monitoring module continuously collects voltage data from each energy storage cell to construct a real-time voltage dataset includes:

[0028] The parallel real-time channel feedback status of the high-frequency hardware comparator detection array is retrieved, and a continuous high-frequency sampling queue is established for all energy storage cell polarity interfaces.

[0029] The real-time voltage data collected in the high-frequency sampling queue is extracted and spliced ​​to construct a voltage ramp-up time series of each energy storage cell as it gradually evolves over time during the charging process. Then, the voltage ramp-up time series is combined and reconstructed into a three-dimensional voltage distribution surface model that reflects the fluctuation of the overall energy storage cell matrix with the charging state over time.

[0030] Optionally, the process of calculating the peak value of the induced electromotive force due to the circuit breaker includes:

[0031] Acquire and analyze the parasitic inductance parameter data of the main power grid and connecting power cables under the power supply connection architecture as the parasitic inductance parameter data of the bus. Simultaneously extract the information of the instantaneous power supply current change rate of the total bus before the trigger point of the circuit breaker command execution as the instantaneous current sudden drop slope parameter of the bus.

[0032] The peak value of the induced electromotive force, which characterizes the peak value of the induced polarization sudden voltage change, is obtained by multiplying the parasitic inductance parameter data of the bus with the slope parameter of the instantaneous current change and fall back of the bus.

[0033] Optionally, the process by which the discharge closed-loop module compares the total voltage across the entire system with a preset cutoff discharge threshold includes:

[0034] Obtain the logical reversal request initiated by the external system based on the physical disconnection identification signal of the main power grid, and construct the discharge model flow direction of the system outputting reverse power supply current to the bus equipment load in reverse;

[0035] Monitor the total system voltage reading output by the energy storage unit matrix, and execute a monitoring mechanism to determine whether the total system voltage reading is greater than the cutoff discharge threshold;

[0036] If the comparison confirms that the total voltage reading of the entire system is greater than the cutoff discharge threshold, then the existing circuit for continuing to discharge to the load of the bus equipment is maintained.

[0037] If the comparison confirms that the total voltage reading of the entire system is less than or equal to the cutoff discharge threshold, a low-level enable command is output to the control coil to control the main circuit relay to cut off the power supply network, and at the same time, the reactive power rebound capture and interception action is initiated on the load side of the bus equipment.

[0038] Optionally, the process of initiating reactive power rebound capture and interception actions on the load side of the bus equipment includes:

[0039] Intercept the flyback reactive power echo electromagnetic inrush current data generated from the load side of the bus equipment at the instant the main circuit relay mechanical moving contact and stationary contact are disconnected due to the low-level enable command;

[0040] When the instantaneous voltage generated by the flyback reactive echo electromagnetic inrush current is higher than the real-time terminal voltage of the super backup capacitor element, the reverse current blocking gating diode matrix is ​​naturally turned on due to forward bias as an introduction channel path, introducing and absorbing the flyback reactive echo electromagnetic inrush current data into the super backup capacitor element for storage and solidification.

[0041] The energy stored in the super backup capacitor drives the central control storage chip to operate continuously to save the log of the power failure state before the circuit is disconnected, and finally cuts off the global power line interaction control within the whole system.

[0042] Optionally, after the delayed action window triggered by the generation of the circuit breaker command ends, the system executes a cyclic takeover process, including:

[0043] After a preset quiet relaxation cooling time, the dynamic evolution monitoring module initiates an overall cyclic scan to read the open-circuit static potential of all energy storage cells.

[0044] By comparing all the open-circuit static potentials, a new selected energy storage cell with the smallest actual value is located and replaced with the previously compensated cell with the smallest voltage, serving as the target node for subsequent relay cycles.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] This application discloses a sodium-ion battery charge-discharge equalization control system for railway passenger cars. This system performs consistency verification on the energy storage cell matrix during the power supply self-test period and anchors the lowest-voltage cell. When any cell reaches the highest safety threshold, it controls the main circuit relay to disconnect and uses a mechanical disconnection delay window to inject the residual parasitic inductance energy at the moment of disconnection into the target node via a magnetic flux coupling transient energy redirection network. Furthermore, at discharge cutoff, it directs the reactive rebound energy from the passenger car equipment load side into the super-backup capacitor element to maintain the state preservation of the control central storage chip. This provides a collaborative control scheme that balances absolute cell safety, low-voltage cell compensation, contact arc suppression, relay life maintenance, and power outage log retention. Compared to existing methods that primarily rely on overall group total voltage control or conventional cell threshold protection, this system effectively improves the problems of insufficient low-voltage cell compensation, direct dissipation of transient energy when cells frequently trigger disconnection at the upper limit, and difficulty in completely preserving state information at the moment of power outage. This enhances the overall capacity utilization, operational stability, and engineering reliability of the railway passenger car backup power supply link. Attached Figure Description

[0047] The present invention will be further explained below with reference to the accompanying drawings and embodiments:

[0048] Figure 1 This is a structural diagram of the system of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0050] like Figure 1 As shown, a sodium-ion battery charge-discharge equalization control system for railway passenger cars includes a main control unit connecting the main power grid and the passenger car equipment load. This main control unit connects a main circuit relay, an energy storage cell matrix, a magnetic flux-coupled transient energy redirection network, a super-backup capacitor element, a high-frequency hardware comparator detection array, a control central storage chip, and a reverse-current blocking gating diode matrix. The main circuit relay includes a control coil and mechanical moving and stationary contacts. The magnetic flux-coupled transient energy redirection network is connected across the two ends of the main circuit relay, and its output is controlled to connect to the energy storage cell matrix. The main control unit includes:

[0051] State anchoring module: During the power supply self-test period, it acquires the initial voltage data of each energy storage cell, marks the cell with the lowest voltage as a specific target node, and controls the main circuit relay to close to connect to the main power grid when the data meets the preset access voltage range conditions;

[0052] Dynamic evolution monitoring module: continuously collects voltage data of each energy storage cell during charging to construct a real-time voltage data set;

[0053] Residual trigger module: Determines the comparison status of the set with the preset highest safety threshold, generates a command to be sent to the control coil to adjust the main circuit relay to maintain connection or disconnect; During the delayed action window period when the disconnect command cuts off the main power grid, it controls the magnetic flux coupling transient energy redirection network to open the physical conduction path to the target node, and injects the residual inductance energy at the moment of disconnection into the target node unidirectionally for compensation.

[0054] Discharge closed-loop module: During discharge, compare the total voltage of the entire system with the preset cutoff discharge threshold. At the instant the power supply network connected to the bus equipment load is cut off, capture the reactive rebound energy data of the load end and transfer it to the super backup capacitor element for storage.

[0055] This embodiment provides a charging and discharging equalization control mechanism for the backup power supply link of railway passenger cars. Specifically, the system is arranged between the railway passenger car battery cabinet and the on-board auxiliary load, serving the entire process of emergency power supply after the train's short-term power replenishment at the platform, standby during operation in the section, and abnormal power failure of the main power grid. The main control unit preferably adopts an industrial control board with isolation sampling capability, which is connected to the main power grid on one side and the passenger car equipment load on the other side, with the main circuit relay connected in series in the middle. The energy storage unit matrix is ​​composed of multiple sodium ion units connected in series, and the magnetic flux coupling transient energy redirection network is connected in parallel at the easily triggered position of the main circuit. The super backup capacitor element and the control central storage chip work together to keep the log saved and the state solidified before the final power failure.

[0056] Specifically, the system's working sequence can be divided into four stages: self-test access, normal charging, overvoltage disconnection compensation, and undervoltage discharge cutoff.

[0057] During the self-test access phase, the state anchoring module reads the initial voltage data of all energy storage cells. For ease of understanding, a simplified four-cell matrix is ​​assumed, with initial voltages of 3.18V, 3.16V, 3.21V, and 3.19V respectively. The module identifies the minimum value of 3.16V, corresponding to the second cell, and records it as the target node for the current cycle. It then determines whether all cells are within the allowed access voltage range, for example, the allowed range can be set to 2.80V to 3.40V. If all four cells are within this range, the control coil is energized, the mechanical moving contact engages with the stationary contact, the main power grid is connected, and charging of the battery pack begins. If any cell is below the lower limit or above the upper limit, engagement is not allowed, the system enters a suppression state, and the fault type is recorded.

[0058] During the normal charging phase, the dynamic evolution monitoring module continuously samples the data through a high-frequency hardware comparator detection array. Taking the above four individual cells as an example, the real-time voltage data set at a certain moment may gradually change from [3.18, 3.16, 3.21, 3.19] to [3.34, 3.31, 3.38, 3.35], and then to [3.55, 3.50, 3.60, 3.57]. Here, the third individual cell reaches the highest safety threshold of 3.60V first. The residual triggering module does not wait for other individual cells to reach the target synchronously, but immediately generates a circuit breaker command and removes the excitation current to the control coil when it detects that at least one value in the set has reached the upper limit.

[0059] It should be clarified that the state anchoring module, dynamic evolution monitoring module, residual triggering module, and discharge closed-loop module here are all pre-compiled and embedded in the control central storage chip, and are low-level program algorithm control logic units that are called and executed in real time by the advanced microprocessor device on the control main unit; among them, the residual of the residual triggering module specifically refers to the logical state of the comparison difference between the real-time voltage data of the energy storage cell and the preset maximum safety threshold.

[0060] The key point is that the mechanical relay does not physically disconnect the moment the control coil is de-energized, but rather has a millisecond-level delay window. The system utilizes this window to control the magnetic flux-coupled transient energy redirection network to open the conduction path to the second cell. Since the main power grid, power cables, and circuit parasitic parameters release residual inductive energy at the moment of disconnection, this energy is shaped by the network into a unidirectional pulse and injected into the lowest voltage cell. For example, if an equivalent compensation pulse is released at the moment of disconnection, raising the second cell from 3.50V to 3.53V, although the overall main circuit has implemented the safety strategy of disconnecting any cell when it reaches its upper limit, the energy that would have caused the contacts to arc is converted into a compensation for the low-voltage cell, thereby gradually reducing the difference between cells in multiple charge-disconnect cycles.

[0061] During the discharge phase, when the main power grid fails or disconnects, the system switches to supplying power to the bus equipment load via the energy storage unit matrix. The discharge closed-loop module monitors the total voltage across the entire system in real time, for example, the total voltage of the four units gradually decreases from 13.8V. When the total voltage is still higher than the cutoff discharge threshold, for example, 11.2V, the load power supply is maintained. When the total voltage drops to 11.2V or below, the system issues a cutoff command. At the instant the bus equipment load is cut off, the load side, such as the motor, fan, and filter, releases flyback or reactive energy into the loop. This energy is not directly dissipated but is introduced into the super backup capacitor element through the reverse current blocking selection diode matrix. The super backup capacitor element then provides short-term holding power to the control central storage chip to complete the storage of information such as the last power failure log, unit voltage snapshot, and relay life count.

[0062] As an alternative control strategy, if the minimum voltage of a single cell is found to be below the absolute safety lower limit during the self-test phase, such as below 2.00V, then no connection will be made, and manual maintenance will be required. If a single cell voltage jump, comparator channel distortion, or communication verification failure occurs during sampling, then targeted compensation will not be performed temporarily, and the redirection network will be put into a closed state to avoid incorrect selection. If the super backup capacitor is already fully charged at the moment of discharge cutoff, then only the rebound energy will be limited and absorbed, and no further charging will be carried out to prevent overvoltage.

[0063] When an intercity railway passenger train enters the platform for power replenishment after completing its journey at the previous station, some of the sodium-ion energy storage cells in the battery cabinet have low voltage due to temperature differences and aging variations from the previous operating cycle. When the train is stationary and the main power grid is reconnected, this embodiment first identifies the cell with the lowest voltage and establishes a target marker. During the power replenishment process, when a cell with a relatively fast voltage rises and reaches the 3.60V upper limit first, the system still strictly executes the disconnection, but at the same time transfers the residual electromagnetic energy that would have impacted the relay contacts at the moment of disconnection to the cell with the lowest voltage. When the train leaves the station and the contact network is abnormal, this embodiment can still maintain emergency power supply until the total voltage reaches the safety lower limit, and then use the rebound energy on the load side to allow the control system time to save the log.

[0064] The purpose of this step is to incorporate the residual energy that would inevitably appear at the moment the relay is disconnected into a controllable path, forming a coordinated closed loop of safe disconnection + low voltage individual unit compensation + control hold, thereby achieving a balance between absolute safety of individual units, relay life maintenance and improvement of overall capacity utilization.

[0065] The magnetic flux coupling feature here essentially refers to the fact that the inductive reactance absorption buffer branch is equipped with an energy storage inductor. When capturing the residual electromagnetic energy released at the moment the main circuit relay is disconnected, the inductor uses the magnetic flux evolution and cross-linking induction law of its own coil to convert the excitation energy of the main power supply circuit into a controlled smooth current, which is then transferred to the absorption circuit.

[0066] In this embodiment, the flux-coupled transient energy redirection network includes an inductive reactance absorbing buffer branch and a multiplexed solid-state switch matrix;

[0067] The inductive reactance absorbing buffer branch is connected in parallel to the two ends of the main circuit relay;

[0068] The current input terminal of the multiplexed solid-state switch matrix is ​​connected to the inductive absorber buffer branch, and the branch output terminals of the multiplexed solid-state switch matrix are electrically connected in parallel to the two pole pins of each energy storage cell.

[0069] The residual triggering module establishes a directional matching physical conduction path by manipulating a specific switch channel in the multiplexed solid-state switch matrix corresponding to the target node.

[0070] This embodiment provides a network topology for controllable transfer of transient energy. Specifically, in the previous embodiment, although it was explained that residual energy at the moment of disconnection can be transferred to the lowest voltage unit, if there is no clear hardware path, this part of the energy may still oscillate randomly in the loop, making it difficult to achieve stable directional injection. Therefore, this embodiment implements the redirection function as a combination structure of an inductive reactance absorbing buffer branch and a multiplexed solid-state switch matrix.

[0071] Specifically, the inductive reactance absorbing buffer branch is directly connected in parallel to the two ends of the main circuit relay. Thus, when the mechanical moving contact and the stationary contact are about to separate or have already begun to separate, the transient energy in the main circuit is preferentially intercepted by this branch, rather than forming a high-amplitude arc in the contact gap. This branch can be composed of an inductor, a capacitor, and a current-limiting element, used to modify the high-voltage peak with a high voltage change rate into a pulse current more suitable for introduction into the individual cell. Preferably, the inductive reactance absorbing buffer branch includes an absorption capacitor and a current-limiting resistor connected in series. This series circuit, as the first absorption branch, is connected in parallel across the two ends of the main circuit relay corresponding to the mechanical moving contact and the stationary contact. The inductor, as a waveform smoothing element, is connected in series between the parallel junction of the first absorption branch and the input of the subsequent multiplexed solid-state switch matrix.

[0072] The input of the multiplexed solid-state switch matrix is ​​connected to the buffer branch mentioned above, and the output is connected to the two pins of each energy storage cell respectively. In this way, the system does not need to deploy a complete absorption channel for each cell, but shares a single energy inlet and then achieves target allocation through different solid-state channels.

[0073] For ease of understanding, taking the aforementioned four-cell matrix as an example, the switch matrix can be understood as four selectable branches, denoted as channels C1, C2, C3, and C4 respectively. The numbers C1 to C4 represent only four candidate conduction switch channels within the multiplexed solid-state switch matrix, corresponding to the first to fourth energy storage cells respectively. These letter identifiers are merely for identification and do not represent additional voltage, current, or capacitance quantities. If the second cell has been determined to be the lowest voltage cell during the state anchoring phase, the residual trigger module, after issuing a circuit breaker command, will only conduct channel C2, while keeping channels C1, C3, and C4 closed. At this time, the transient energy intercepted by the inductive reactance absorbing buffer branch will only flow along the path from the relay terminals → buffer branch → channel C2 → second cell. If the lowest voltage cell becomes the fourth cell in the next cycle, the residual trigger module will switch to conduction channel C4, achieving conduction path switching.

[0074] Without introducing this multiplexing topology, the most direct approach would be to configure an independent energy recovery branch for each individual cell. However, in railway passenger car battery boxes, the number of individual cells is large, space is limited, and vibration resistance requirements are high. Independent branches would lead to a multiple increase in the number of devices or a direct increase with the number of individual cells, resulting in increased wiring length and exacerbating the uncertainty of parasitic parameters. Therefore, this embodiment adopts a shared absorbing inlet combined with a selective channel, which effectively simplifies the hardware scale and control logic complexity.

[0075] As an alternative control strategy, if the residual triggering module detects a conflict between two conditions at a certain moment, such as the target node update not being completed but the relay disconnection being triggered, the protection strategy will be prioritized: all solid-state switches will be turned off, and only the buffer branch will undertake the wave absorption task, and the target node will be re-anchored in the next cycle; if a solid-state channel is determined to have abnormal leakage current during self-test, the channel will be marked as disabled, and the transient compensation function of the corresponding unit will be turned off, and a maintenance alarm will be issued directly if necessary.

[0076] It should be noted that the disabling here refers to the energy redirection action of the corresponding solid-state switch channel, rather than negating the objective result of the energy storage cell in the voltage ranking; even if the cell still shows the actual lowest voltage cell in subsequent scans, the system will only record it as an abnormally weak cell and keep the redirection network closed until the channel fault is repaired and restored, thereby avoiding the situation where the target identification result is confused with the actual executable conduction path.

[0077] During the continuous power replenishment process of the same railway passenger car, the second unit is the lowest voltage unit in the first few disconnection cycles. Therefore, the system continuously selects channel C2 to form repeated pulse compensation. As the compensation accumulates, the second unit is no longer the lowest, and the lowest value is transferred to the fourth unit. At this time, there is no need to change the main circuit structure. It is only necessary to control the main unit to switch to channel C4 in the next disconnection window to direct the residual energy to the new weak unit.

[0078] The purpose of this mechanism is to use a defined hardware topology to transform transient energy from uncontrollable transient high voltage spikes or destructive voltage spikes into selectable unidirectional compensation pulses, thereby achieving directional balance between different cells and reducing the risk of contact arcing.

[0079] In this embodiment, the process of the state anchoring module extracting the minimum voltage cell and marking the minimum voltage cell as the target node includes:

[0080] Extract the steady-state static voltage value of each energy storage cell in the energy storage cell matrix within the preset monitoring time.

[0081] Retrieve the preset voltage consistency tolerance threshold range and calculate the maximum absolute difference between each static voltage steady-state value to configure it as the full matrix limit deviation parameter;

[0082] If the limit deviation parameter of the entire matrix is ​​less than the voltage consistency tolerance threshold, the associated energy storage cell with the smallest actual value is selected from each static voltage steady-state value, and the associated energy storage cell is established as the smallest voltage cell and marked as the target node accordingly.

[0083] If the limit deviation parameter of the entire matrix is ​​greater than or equal to the voltage consistency tolerance threshold, an instability alarm signal of the matrix unit is issued, and the main circuit relay is kept in the disconnection suppression state to prevent power supply.

[0084] This embodiment provides a reliable anchoring mechanism for target nodes during the initialization phase. Specifically, although the previous-level scheme can find the lowest voltage cell from multiple cells, if the consistency deviation of the energy storage cell matrix itself exceeds the preset safety tolerance range, sampling drift occurs, or a certain cell has experienced abnormal degradation, relying solely on a simple minimum value screening may treat the faulty cell as an ordinary low-voltage cell, amplifying the risk in subsequent access. Therefore, this embodiment first checks the consistency of the entire group before deciding whether to allow access and whether to mark the target node.

[0085] Specifically, the state anchoring module does not make judgments at a single instantaneous sampling point, but rather extracts the steady-state value of static voltage within a pre-set monitoring time. For example, after a passenger bus stops at the station, it waits for 30 seconds before collecting voltage data 10 times at a frequency of once per second, and then calculates the average value for each individual unit to obtain a more stable static value. Assuming the steady-state values ​​of the four individual units are 3.22V, 3.20V, 3.23V, and 3.21V, the maximum absolute difference between the individual units is 0.03V. If the preset consistency tolerance threshold is 0.08V, then 0.03V is less than 0.08V, indicating that the matrix as a whole is in an accessible state. At this time, the second individual unit with a voltage of 3.20V is marked as the target node.

[0086] Here's another set of abnormal data: if the steady-state values ​​of the four individual cells are 3.25V, 2.91V, 3.24V, and 3.23V, then the maximum absolute difference reaches 0.34V. This value significantly exceeds the tolerance threshold of 0.08V, indicating that at least one of the individual cells has an abnormal deviation, wiring abnormality, or sampling abnormality. In this case, the system temporarily suspends the program of setting the individual cell corresponding to 2.91V as the compensation target, and instead directly outputs a matrix unit instability alarm. At the same time, the main circuit relay is kept open, and connection to the main power grid is prohibited to prevent the faulty individual cell from further losing control under high current conditions.

[0087] The reason for adding this consistency judgment is that the battery cabinets of railway passenger cars are usually subjected to vibration, temperature difference and cable connection conditions that exceed the conventional calibration threshold. Sometimes the voltage deviation of a single cell is not a normal difference in state of charge, but may be caused by loose connecting bolts, poor contact of sampling lines or a sudden increase in the internal resistance of a single cell. If charging is started directly, it will not only be difficult to achieve equalization, but may also lead to local overheating.

[0088] As an alternative control strategy, if individual sampling points change abruptly during the monitoring period, such as a sample being more than 0.20V higher than the adjacent sample, the abnormal point can be removed and the steady-state value recalculated. If the number of valid samples after removal is less than the minimum requirement, such as less than 5 samples, the entire group is judged as unreliable and access is not performed. If the limit deviation of the entire matrix is ​​exactly equal to the tolerance threshold, the conservative strategy is adopted to regard it as not meeting the access conditions, and the relay is still kept off.

[0089] Before the nighttime power replenishment of the same railway passenger car begins, the car has been parked for a long time and the battery pack temperature is low. The main control unit first performs static sampling to confirm that the steady-state voltage difference of each cell is within a reasonable range before allowing the main circuit relay to engage. If the potential difference between a cell and the other cells is found to exceed the range threshold, the on-site maintenance personnel can first check the tab connection, sampling line and the status of the cell to avoid the system from continuing to charge under fault conditions.

[0090] The purpose of this step is to first eliminate the false low-voltage effect caused by the fault, and then perform targeted compensation for the normal low-voltage cells, thereby ensuring safe access and the accuracy of subsequent compensation.

[0091] In this embodiment, the process by which the residual triggering module determines the comparison status between the real-time voltage data set and the preset maximum safety threshold to generate a switching command includes:

[0092] If all real-time voltage data in the real-time voltage data set are less than the maximum safety threshold, a keep-connection command is generated to maintain the excitation current input to the main circuit relay control coil without decay, and to perform a continuous power loading operation to connect to the main power grid.

[0093] If at least one real-time voltage data point in the real-time voltage dataset is greater than or equal to the maximum safety threshold, a circuit breaker command is generated to remove the excitation current for the control coil, and the energy transient transfer equalization process is activated for processing.

[0094] This embodiment provides a triggering logic for intermittent switching during the charging phase. Specifically, after initial screening, although the system can safely connect to the main power grid, if the disconnection conditions are not set reasonably, two types of problems may occur: one is response lag, causing individual units to exceed the safety limit; the other is poor anti-interference capability, generating high-frequency oscillations under short-term noise, causing relays to open and close ineffectively. Therefore, this embodiment clarifies the determination mechanism for the charging phase as follows: if all units are below the threshold, the connection is maintained; if any unit reaches the threshold, the connection is immediately disconnected and the equalization process is triggered.

[0095] Specifically, the highest safety threshold is set to 3.60V; the main control unit acquires a real-time voltage data set once per sampling cycle and performs parallel comparisons; taking the aforementioned four individual units as an example:

[0096] When the set is [3.48, 3.46, 3.52, 3.49], all values ​​are less than 3.60V. The system outputs a connection-maintaining command, the control coil is continuously energized, the main circuit relay remains energized, and charging continues.

[0097] When the set changes to [3.56, 3.53, 3.60, 3.58], the third individual cell reaches 3.60V. The system immediately outputs a circuit breaker command, removes the excitation current of the control coil, and hands over the subsequent process to the transient transfer balancing process. At this time, it is not necessary to wait for all individual cells to reach the upper limit synchronously, because the absolute safety of individual cells must be given priority in the power replenishment process of railway passenger cars.

[0098] Compared to the simple method of disconnecting when the total pressure reaches a certain value, this embodiment directly monitors each cell, which helps to avoid overcharging of the first cell that is fully charged due to differences in cell consistency. At the same time, since the subsequent disconnection is not just passive but is combined with transient energy redirection, this strategy of disconnecting at any threshold will not waste the energy at the moment of disconnection.

[0099] As an alternative control strategy, if a channel in the real-time data experiences a momentary jitter that happens to touch 3.60V, and multiple adjacent sampling periods are significantly lower than this value, the hardware comparator output can be required to meet the minimum duration condition, for example, disconnection is only confirmed when two consecutive sampling periods are not lower than the threshold. If the sampled value exceeds the sensor's confidence range, for example, a single section momentarily displays 4.50V, it is first judged as a sampling abnormality and the transfer process is temporarily suspended, while a channel fault alarm is issued. If multiple individual sections reach or exceed the threshold at the same time, a disconnection action can still be performed, and the subsequent target nodes are not determined based on the number of high-voltage individual sections, but continue to be determined based on the previously anchored lowest voltage individual section.

[0100] At the end of the rapid power replenishment process at the train platform, due to the inherent differences in the consistency of individual cells, a certain cell often reaches its upper limit first. Once the system recognizes this state, it immediately removes the relay excitation and stops the main power grid from continuously supplying energy to the battery pack, thereby ensuring that the individual cell voltage is maintained within the safe boundary range. At the same time, the disconnection energy that would have become a burden on the electric arc is introduced into the subsequent process to compensate for the previously identified low-voltage lagging cells.

[0101] The purpose of this mechanism is to establish clear, executable, and engineering-stable disconnection criteria, so as to form a definite switching condition between continuous charging of the main circuit and forced termination, thereby achieving reliable triggering of safety threshold control and subsequent equalization processes.

[0102] In this embodiment, the process of activating the energy transient transfer equalization step includes:

[0103] Step 1: Record the pre-calibrated mechanical disconnection delay time constant that occurs between the issuance of the circuit breaker command and the physical separation of the mechanical moving contact from the stationary contact of the main circuit relay. Determine that the mechanical disconnection delay time constant is the delay operation window period.

[0104] Step 2: During the delayed action window, extract the parasitic inductance parameters of the bus and the slope parameters of the sudden change in the instantaneous current of the bus, and calculate the peak value of the induced electromotive force generated by the circuit breaker.

[0105] Step 3: Control the switching action of the multiplexed solid-state switch matrix to close the physical conduction path of the target node. The peak data of induced electromotive force is reconstructed into transient current pulse data through the waveform trimming of the inductive reactance absorbing buffer branch. The transient current pulse data is then applied to the target node in the lowest voltage state along the physical conduction path to perform forced current injection compensation.

[0106] Step 4: Combining the peak-shaving effect of induced energy during waveform trimming and reconstruction dissipation, a non-arc-induced degraded disconnection response is completed at the contact separation surface of the main circuit relay.

[0107] This embodiment provides a time-sequential processing mechanism for instantaneous energy redistribution during disconnection. Specifically, the previous-level scheme provides the criteria for when to disconnect, but if only this level is achieved, the disconnection action may still remain in the traditional hard cut-off mode, and cannot be compensated by the time difference of mechanical disengagement. Therefore, this embodiment further refines the transient energy transfer into an executable four-step process.

[0108] Specifically, the first step is to determine the delayed action window; there is usually a pre-calibrated time constant, such as 15ms, from the de-energization of the control coil to the complete separation of the moving contact from the stationary contact of the mechanical relay; this time constant can be measured at the factory by the test fixture, or it can be updated and written into the control central memory chip during vehicle maintenance; after the system issues the circuit breaker command, it regards this 15ms as the available window, rather than treating the disconnection as an event that is completed at zero time.

[0109] The second step is to estimate the recoverable induced energy during the window period. For example, if the bus parasitic inductance is equivalent to 20μH, the bus current is 50A before disconnection, and there is a drop in current higher than the set rate of change within a preset time period, then the induced surge will form a peak trend in the main circuit. The control unit does not need to perform complex high-dimensional calculations, but generates an energy level estimate based on the parasitic inductance and the current drop slope, for example, divided into three levels: low, medium, and high, to select the subsequent conduction width and current limiting strategy.

[0110] The third step is to perform targeted conduction and pulse injection. For example, if the current targeted node is still the second cell, its voltage lags behind other cells by 0.05V, the system quickly closes the corresponding solid-state channel within a 15ms window, so that the pulse shaped by the buffer branch is injected only into the second cell. If a pulse current lasting tens to hundreds of microseconds is obtained after shaping, this current will not cause long-term overcharging, but it is sufficient to compensate for a certain amount of charge each time it is disconnected. Assuming that each disconnection compensates 0.001Ah, the difference between cells can be gradually reduced after multiple rounds of compensation.

[0111] The fourth step is to utilize the circuit state after peak clipping to complete low-arc or non-arc disconnection; when the induced peak value is carried away by the buffer branch and the targeting path, the voltage and current burden on the contact separation surface is greatly reduced, and the actual burn-out of the relay is reduced accordingly; in other words, the compensation action and the contact protection are not independent of each other, but are jointly achieved by the same transient energy path.

[0112] Without this time-sequential process, if balancing is only considered after disconnection, the energy window in the effective recovery range is often missed. If relying entirely on additional DC-DC converter balancing units, the volume, heat dissipation, and failure points in the bus battery cabinet will increase. This embodiment utilizes the inherent disconnection delay of mechanical relays to transform the inevitable physical process into a balancing opportunity.

[0113] As an alternative control strategy, if the measured mechanical disconnection time deviates significantly due to temperature or aging, for example, from 15ms to 9ms, the system can automatically adopt a conservative value with a shorter window to avoid conduction timeout; if the estimated induced energy exceeds the upper limit of the target node's allowable injection, the amplitude is limited by shortening the solid-state conduction time or increasing the dissipation ratio of the buffer branch; if the target node is no longer at its lowest point just before disconnection, compensation will still be performed once as if the node has been locked, and the node will be reselected in subsequent cycles to ensure timing stability.

[0114] During a specific disconnection cycle of the power supply at the end of the train platform, the third unit first reaches 3.60V; after the main control unit issues the circuit breaker command, the relay still has about 15ms of mechanical action margin; the system reads the trend of the bus current drop in this window, judges that a medium-intensity compensation pulse can be formed, and quickly conducts the corresponding channel of the second unit, so that the buffer branch shapes the spike into a restricted pulse and injects it into the second unit; when the moving contact is completely separated, the main circuit has already been disconnected in a low arc or even no obvious arcing state;

[0115] The purpose of this step is to expand the circuit breaking action from simply stopping the power supply to a combined process of using the circuit breaking to compensate and suppress the contact arc, thereby achieving the synchronization of transient energy recovery and mechanical device protection.

[0116] In this embodiment, the process by which the dynamic evolution monitoring module continuously collects voltage data from each energy storage cell to construct a real-time voltage data set includes:

[0117] The parallel real-time channel feedback status of the high-frequency hardware comparator detection array is retrieved, and a continuous high-frequency sampling queue is established for all energy storage cell polarity interfaces.

[0118] Real-time voltage data collected from the high-frequency sampling queue are extracted and spliced ​​to construct a voltage ramp-up time series of each energy storage cell as it gradually evolves over time during the charging process. This voltage ramp-up time series is then combined and reconstructed into a three-dimensional voltage distribution surface model that reflects the fluctuation of the overall energy storage cell matrix with the charging state over time.

[0119] This embodiment provides a dynamic evolution monitoring mechanism for fine-grained observation of the charging process. Specifically, the previous-level scheme can trigger disconnection at a single sampling point. However, in the high-current charging environment of railway passenger cars, the voltage of individual cells does not rise smoothly and linearly, but often exhibits different ramp-up rates due to temperature rise, wiring impedance, and power supply fluctuations. If only the threshold is recorded, it is difficult to identify in advance which cell is close to the upper limit and which cell lags behind for a long time, which is not conducive to the optimization of the targeted compensation strategy. Therefore, this embodiment further constructs the sampling results into a time series and a three-dimensional distribution model.

[0120] Specifically, the high-frequency hardware comparator detection array can be connected in parallel to all individual polarity interfaces to perform sampling at a frequency higher than the mechanical response speed of the relay. For clarity, assume that at the first to fourth consecutive adjacent sampling times t1, t2, t3, and t4 obtained by the four individual cells according to a unified sampling clock sequence, the continuous voltage data sequence collected by the first individual cell is constructed as [3.30, 3.38, 3.47, 3.56], the continuous voltage data sequence collected by the second individual cell is constructed as [3.26, 3.33, 3.41, 3.50], the continuous voltage data sequence collected by the third individual cell is constructed as [3.32, 3.41, 3.52, 3.60], and the continuous voltage data sequence collected by the fourth individual cell is constructed as [3.29, 3.37, 3.46, 3.57].

[0121] Expanding each individual cell along time yields four corresponding voltage ramp-up time series. Then, multi-dimensional combination reconstruction is performed using the cell number as a parameter axis, the sampling time as a parameter axis, and the real-time voltage value as a parameter axis, forming a three-dimensional voltage distribution surface that reflects the overall matrix state. By observing the surface distribution model data processed by the system backend, it can be intuitively deduced that the voltage ramp-up of the third cell is the fastest, and that of the second cell is the slowest, indicating that the potential energy distribution in the system is not uniform.

[0122] This type of distribution model can be used to assist control at two levels: first, to predict the most likely cell to reach its limit before it approaches the upper limit, thus making disconnection preparation more relaxed; second, to track whether the long-term lagging cells continue to lag behind. If they continue to lag behind for more than a number of charge-discharge cycles, it indicates that the cell may be experiencing accelerated aging or an increase in internal resistance.

[0123] If such a time-continuous model is not established, and the judgment is only made at the threshold point, the system can only perform the circuit breaking operation based on the current threshold, and cannot trace the historical evolution factors of the abnormal voltage rise of a specific unit, making it difficult to provide support for subsequent maintenance and parameter calibration.

[0124] As an alternative control strategy, if a sampling channel loses data for a short period of time, the method of geometric interpolation of the nearest time point can be used to fill in the single accurate point. However, if the continuous loss exceeds the preset length, the channel should be marked as measurement abnormal and invalid. If the sampling clocks of different channels are offset, they should be re-aligned with a unified reference clock before reconstruction and splicing to avoid incorrect construction of the three-dimensional surface model. If the reconstruction process of the corresponding surface shows that the voltage of all individual cells generally has a synchronous large jump, it should be preferentially judged as an external power supply disturbance rather than an independent internal state change of individual cells.

[0125] During multiple power replenishment cycles at various stations on the same passenger train, the control unit cumulatively recorded the ramp-up curves of each individual unit. The maintenance system analyzed the constructed historical evolution reconstruction surface and determined that the third unit always approached the safety limit first, while the second unit always lagged significantly behind. Combined with the targeted compensation results data executed at the moment of disconnection, it can be determined that the second unit belongs to a unit with long-term high internal resistance or abnormal capacity decay. Its contact impedance and unit health can be monitored in the future.

[0126] The purpose of this mechanism is to extend discrete independent threshold control criteria to three-dimensional observation and tracking of continuous processes, thereby achieving a precise grasp of the dynamic global characteristics of charging and providing underlying data support for disconnection preparation, targeted compensation determination, and subsequent operation and maintenance testing.

[0127] In this embodiment, the process of calculating the peak value of the induced electromotive force generated by the circuit breaker includes:

[0128] Acquire and analyze the parasitic inductance parameter data of the main power grid and connecting power cables under the power supply connection architecture as bus parasitic inductance parameter data, and simultaneously extract the information of the total bus instantaneous power supply current change rate before the corresponding circuit breaker command execution trigger origin as the bus instantaneous current sudden drop slope parameter.

[0129] The peak value of the induced electromotive force, which characterizes the peak value of the induced polarization sudden voltage change, is obtained by multiplying the parasitic inductance parameter data of the bus with the slope parameter of the instantaneous current change and fall back.

[0130] It should be specifically pointed out that the peak value of the induced electromotive force extracted here through algebraic multiplication is actually the peak value of the equivalent excitation terminal voltage, which characterizes the intensity of transient electromagnetic shock. The system bottom layer indirectly quantifies and maps the instantaneous shock energy level parameter that the system needs to perform discharge transfer operation by classifying and evaluating the amplitude level of the extracted voltage peak value.

[0131] This embodiment provides a simplified calculation mechanism for transient energy level estimation. Specifically, the previous scheme has given the general idea of ​​extracting bus parasitic inductance and current change parameters within the disconnection window. However, without a clear estimation method, the control unit will find it difficult to set a reasonable conduction strategy according to different line conditions. Therefore, this embodiment clarifies that the source of the peak induced electromotive force data is the combined estimation of bus parasitic inductance parameters and current sudden change fall slope.

[0132] Specifically, there are usually long power cables, connection terminals, and relay bodies between the main power grid of a railway passenger car and the battery cabinet. These structures together form an equivalent parasitic inductance. This parasitic inductance does not need to be measured precisely in real time every time. A reference quantitative value can be given in advance by the line length, cable specifications, and maintenance calibration table, or it can be directly measured during the commissioning phase by excitation with a known waveform. For example, the equivalent parasitic inductance of the busbar of this car can be approximately denoted as 20μH.

[0133] Before the circuit breaker command is issued, the system synchronously and continuously reads the change trend of the instantaneous power supply current in the main bus. Assuming that the current value before the current breaker is intercepted is about 40A, and the short-term fallback polarization slope is estimated to be 8A / μs based on high-frequency sampling, the control master unit establishes an algebraic product operation between the 20μH parasitic inductance parameter and the 8A / μs fallback slope parameter, and calculates the control estimate used to characterize the evolution trend of the peak voltage of the induced polarization sudden change. According to the above example, its magnitude can correspond to a predicted terminal voltage spike of about 160V.

[0134] It should be noted that the naming label used in this embodiment for the peak value of the induced electromotive force refers to the data reference item used by the main control unit to predict and determine the boundary of energy transfer intensity. It does not directly equate the above product calculation result to the Joule energy value under the strict physical energy measurement system at the microscopic level. The actual available compensation power that is actually cut into the target node is also affected by the shunt voltage limit of the peripheral buffer branch, the series voltage drop of the switching device, the actual pulse conduction time, and the synergistic effect of the heat dissipation ratio characteristics.

[0135] The system does not require this value to be introduced into deep, purely theoretical, and complex analysis. Instead, it maps it to a multi-level discrimination criterion in the control logic algorithm: for example, when the estimated value generated by the deduction is lower than the calibration threshold set at the first level, it is directly determined to trigger a low-energy pulse condition; when the estimated value is exactly between the calibration threshold at the first level and the boundary set at the second level, it is determined to trigger a medium-energy pulse condition; and if the estimated value generated by the deduction even exceeds the upper limit threshold set at the second level, it is automatically located and determined to trigger a high-energy heavy pulse condition that includes peak shaving requirements. Correspondingly, the main control drive system can independently judge the output result based on this and adaptively execute short-window conduction, medium-level flat-window conduction, or non-saturated conduction strategy with forced overload limiting protection for different conditions.

[0136] Without this pre-estimation mechanism, the system can only use a fixed-allocation constant conduction duration and a single topology path for discharge conduction, which can easily lead to insufficient compensation of individual units in the low-energy range, or apply high-voltage pulses exceeding safety limits to the target node during high-energy impacts, causing irreversible hardware damage. Especially in typical railway vehicle operation scenarios, the parasitic effects introduced by long-span cables will exceed the calibration range of ordinary short-distance enclosed equipment. Therefore, it is necessary to calculate and establish them as quantifiable dynamic adaptive control parameters through linear algorithms.

[0137] As an alternative control strategy, if the actual parasitic inductance parameter calculated after the actual line is modified and the initial storage value is mismatched with the calibration value, the parameter definition table and weight can be updated through the underlying maintenance correction protocol interface; if the extreme value of the sudden current fall slope obtained by the high frequency measurement circuit sampling capture shows an amplitude characteristic that exceeds the set safety range, but shows a serious sluggish or inconsistent logical deviation with the current action record of the relay switch contact stroke, then the extreme value can be pre-judged as an external occasional transient spike interference, and the confidence filter channel parameters stored in the previous reliable cycle will be called by default to perform the substitution operation.

[0138] If the induced peak estimation parameters obtained by the final product operation exceed the upper limit of the safety bearing capacity of the underlying system, the control program will intercept the switch control command corresponding to the abnormal high extreme value and perform extreme value truncation processing to limit it within the system standard protection upper limit parameter area to prevent the underlying layer from causing a breakdown short circuit safety accident due to abnormal channel crosstalk values.

[0139] In the same high-speed train, the carriages located near the pantograph high-voltage side of the main feeder have cable lengths below the preset distance threshold, and their physical equivalent parasitic inductance values ​​are within the first parameter range. However, the trailer carriages located at the rear, away from the power receiving position, have power cables exceeding the preset distance threshold and multiple relay nodes, resulting in a non-linear increase in parasitic inductance constant. Even when facing the same busbar rated disconnection load, the electrical load nodes at these two different distances will inevitably exhibit transient overlapping peak characteristics with drastically different peak intensity levels due to the difference in the underlying inductive energy storage of the system.

[0140] This mechanism relies on independently and actively calling and reading the equivalent deduction parameter table of the basic line that has been saved and entered in the corresponding associated carriage, and combining it with dynamic superposition and real-time extraction of calculation basis such as the rapid current drop fluctuation and sudden change trend of the power supply feeder before disconnection. It automatically adapts to the corresponding settlement selection to generate different matching safety level window widths of the drive pulse conduction bandwidth time and channel, so that each transient transfer impact absorption compensation intervention action at the break can be highly targeted and accurately adapted to the unique and isolated underlying dynamic electromagnetic evolution bus application environment of each carriage.

[0141] The purpose of this mechanism is to provide a basis for accurate quantitative calculation and judgment for capturing the transient uncertainty reabsorption compensation process. This enables the dynamic conduction adjustment strategies of various multiple channels in the main control link to change the control method that relies on fixed empirical thresholds. It realizes dynamic closed-loop intervention control based on the evolution characteristics of the power supply line and the intensity of the transient current change, thereby taking into account both the transient compensation effect and the underlying safety margin of the system. Based on the characteristic parameters of the power supply line and the intensity of the transient current change, it performs adaptive dynamic closed-loop intervention to take into account both the transient compensation effect and the underlying safety margin of the system.

[0142] In this embodiment, the process by which the discharge closed-loop module compares the total voltage across the entire system with a preset discharge cutoff threshold includes:

[0143] Obtain the logic reversal request initiated by the external system based on the physical disconnection identification signal of the main power grid, and construct the discharge model flow direction of the system outputting reverse power supply current to the bus equipment load in reverse;

[0144] Monitor the total voltage reading of the entire system output by the energy storage unit matrix, and execute a monitoring mechanism to determine whether the total voltage reading of the entire system is greater than the cutoff discharge threshold;

[0145] If the comparison confirms that the total voltage reading of the entire system is greater than the cutoff discharge threshold, then the existing circuit for continuing to discharge to the bus equipment load will be maintained.

[0146] If the comparison confirms that the total voltage reading of the entire system is less than or equal to the cutoff discharge threshold, a low-level enable command is output to the control coil to control the main circuit relay to cut off the power supply network, and at the same time, the reactive power rebound capture and interception action is initiated for the load side of the bus equipment.

[0147] This embodiment provides a closed-loop discharge control mechanism for mainline network failures. Specifically, in the aforementioned implementations, the system focuses on charging disconnection and transient compensation. However, the backup power supply for railway passenger cars must also cover emergency discharge scenarios where the mainline network is physically disconnected. If only charging safety is considered while discharge cutoff control is ignored, the battery pack may be over-discharged during the fault power supply process, affecting subsequent recovery and lifespan. Therefore, this embodiment provides reverse power supply logic and total voltage cutoff control after the mainline network is disconnected.

[0148] Specifically, when an external signal indicating physical disconnection from the main grid is detected, the control unit receives a logic reversal request, and the energy flow of the system switches from the main power grid → battery matrix to the battery matrix → bus equipment load; at this time, the discharge closed-loop module starts to continuously monitor the total voltage of the entire system; for ease of explanation, a simplified four-cell matrix is ​​set to a cutoff discharge threshold of 11.2V.

[0149] If the total voltage measured by the current system is 12.6V, it obviously meets the judgment standard of being greater than the set threshold of 11.2V. The system continues to maintain the closed-loop connection of the drive control loop to maintain the discharge drive of the core bus equipment loads such as the carriage lighting, communication system, and underlying control devices. As the load continues to discharge, if the total voltage of the entire system gradually drops to nodes such as 11.8V, 11.5V, and 11.3V, as long as the monitored value is still higher than the cutoff discharge threshold, the control module will maintain the power supply state. Once the total voltage of the entire system drops to 11.2V or falls to the lower limit of 11.1V, the underlying judgment module will determine that the over-discharge protection condition has been met. Immediately, the internal control main unit will output a low-level circuit break command to the control coil of the main circuit relay, controlling the main circuit relay to disconnect the external power supply network to terminate the continued discharge to the vehicle equipment.

[0150] The reason for adopting total pressure instead of continuing to use the highest threshold of a single cell or the local isolated single-cell judgment scheme at this stage is that the core protection objective of the extreme emergency discharge stage is to avoid damage to the energy storage cell matrix due to excessive discharge. At the same time, based on the underlying independent multi-channel individual cell cross-monitoring technology base network that is already widely available in the whole system, we can take advantage of the situation to extract and summarize the total output statistical aggregation indicators that better reflect the overall macro-robust characteristics of the entire domain to determine the timing and entry point for triggering the global macro-cutoff operation of the entire system-level protection.

[0151] When railway passenger cars are dealing with a sudden power outage in the main line network, the core of their control lies in assessing the total time for maintaining stable power supply with the remaining power and executing a protection strategy of overall physical disconnection when the total voltage drops to the design lower limit threshold. The total voltage threshold cutoff decision algorithm system is used as the highest priority disconnection condition, which can meet the final control requirements for safe shutdown of the system.

[0152] As an alternative control strategy, if the physical disconnection identification signal of the main grid is inconsistent with the downward trend of the total voltage, for example, if disconnection is detected but the total voltage still shows an increase in charging, the system needs to check the contactor status before switching modes; if the total voltage sampling is distorted or missing, the conservative criterion of using the most recent reliable value combined with the lowest value of the individual unit is used to disconnect in advance; if the total voltage fluctuates around the threshold, for example, repeatedly jumping between 11.19V and 11.22V, a hysteresis band condition can be added, such as disconnection when the voltage is less than or equal to 11.2V, and reconnection is only allowed when the voltage is higher than 11.4V.

[0153] When a railway passenger car encounters a power supply anomaly from the main line network while running in a section, the lighting and communication systems inside the car are powered by sodium-ion batteries. The discharge closed-loop module continuously summarizes the total voltage of the entire matrix. When the total voltage is still higher than the safety lower limit, the on-board load operation is maintained. Once the total voltage reaches the lower limit, the system controls the relay to disconnect and hands over the subsequent load-side rebound energy capture action to the subsequent mechanism for processing.

[0154] The purpose of this mechanism is to establish a clear emergency discharge boundary in the event of a mainline grid failure, thereby achieving a controllable balance between battery pack discharge safety, load continuity and system-level disconnection timing.

[0155] In this embodiment, the process of initiating the reactive power rebound capture and interception action on the load side of the bus equipment includes:

[0156] Intercepting the flyback reactive echo electromagnetic inrush current data generated from the load side of the bus equipment at the moment when the main circuit relay mechanical moving contact and stationary contact are disconnected due to the low-level enable command;

[0157] When the instantaneous voltage generated by the flyback reactive power echo electromagnetic inrush current is higher than the real-time terminal voltage of the super backup capacitor element, the reverse current blocking gating diode matrix is ​​naturally turned on due to forward bias as the introduction channel path, introducing the flyback reactive power echo electromagnetic inrush current data and absorbing and buffering it into the super backup capacitor element for storage and solidification.

[0158] Relying on the energy stored in the super backup capacitor, the central storage chip is driven to operate continuously to complete the logging of the power failure state before the circuit is disconnected, and finally cut off the global power line interaction control within the whole system.

[0159] This embodiment provides an energy interception mechanism for power preservation in a control system at the moment of discharge cutoff. Specifically, the previous solution has already achieved the cutting off of load power supply when the total voltage reaches the lower limit. However, if the control main unit also loses power synchronously after the cutting-off action is completed, the fault state before the power failure, the individual voltage snapshot, and the relay action record may not be written to the control central storage chip, making it difficult for subsequent maintenance personnel to trace the fault process. Therefore, this embodiment transforms the load-side flyback reactive power echo electromagnetic inrush current data from harmful rebound into short-term control to preserve energy.

[0160] Specifically, when the discharge closed-loop module confirms that the total voltage of the entire system is less than or equal to the cutoff discharge threshold, the control main unit outputs a low-level enable command to the control coil, causing the mechanical moving contact and stationary contact of the main circuit relay to enter the disconnection process. For the bus equipment load, there may still be magnetic field energy or reactive energy stored in the input terminals of the lighting driver, ventilation motor, filter inductor and auxiliary converter. This part of the energy will generate flyback or echo electromagnetic inrush current to the power supply circuit at the moment of circuit breaking. If no controlled path is set, the inrush current may impact the contact gap or enter the control circuit through an unexpected path.

[0161] This embodiment establishes a unidirectional input channel path through a reverse-current blocking gating diode matrix. The function of this diode matrix is ​​not to allow the super backup capacitor element to discharge in reverse to the bus equipment load, but to allow the rebound energy to flow unidirectionally into the super backup capacitor element when the rebound voltage on the load side is higher than the terminal voltage of the super backup capacitor element and the conduction condition is met. In this way, the flyback reactive power echo electromagnetic inrush current data released on the load side of the bus equipment is absorbed and buffered into the super backup capacitor element, which reduces the circuit impact at the moment of disconnection and also provides a short time to maintain power supply for the control central storage chip.

[0162] For ease of understanding, assume that the voltage of the super-backup capacitor element is in a low holding state before the system discharges to the cutoff, and a short rebound pulse appears at the load end at the moment the relay is disconnected; the reverse current blocking gating diode matrix detects that the rebound direction matches the introduction direction and then conducts, allowing the rebound energy to enter the super-backup capacitor element through the current limiting path; the super-backup capacitor element provides holding power to the central control storage chip for hundreds of milliseconds to several seconds, enabling it to complete the recording and saving of the last power failure status log, the total voltage of the entire system, the last voltage of each energy storage unit, the main grid disconnection flag, the relay action count, and the reactive power rebound capture status;

[0163] It should be noted that the so-called "reserve solidification" does not mean that the transient electromagnetic inrush current is preserved in its original waveform for a long time. Rather, it refers to the conversion of transient energy into short-term DC holding energy that can be used by the controllable central storage chip through the super-backup capacitor element. After the controllable central storage chip completes the writing, the control main unit then shuts down the relevant sampling branch and gating branch, so that the global power line interaction control within the whole system is finally cut off, avoiding the continued consumption of the residual power of the energy storage unit matrix under low voltage conditions. Furthermore, the "persistent operation" here refers to the controllable central storage chip continuously completing the necessary state writing and safety termination within the controlled holding time, as opposed to its long-term continuous power supply operation after the main circuit is disconnected. The corresponding holding time is limited to meet the requirements of log saving, key flag solidification, and orderly shutdown, and then it exits the working state.

[0164] As an alternative control strategy, if the super-backup capacitor element is already fully charged or nearly fully charged before being disconnected, the reverse current blocking selection diode matrix, together with the limiting absorption branch, only performs peak clipping absorption and no longer charges the super-backup capacitor element with energy exceeding the safety limit. If the load-side rebound pulse amplitude is insufficient to turn on the diode matrix, the system does not force capture, but relies on the original energy storage of the super-backup capacitor element to complete the minimum log writing. If a reverse leakage abnormality is detected in the diode matrix, the discharge closed-loop module issues a maintenance alarm in advance and shortens the control hold process at the next discharge cutoff, saving only the necessary status fields.

[0165] When a railway passenger car is running in a section, emergency lighting and communication are maintained by sodium-ion batteries. When the total voltage of the entire system drops to the cutoff discharge threshold, the main circuit relay disconnects the load power supply. At this time, the flyback energy released by the input terminal of the ventilation fan driver and the filter is directed by the reverse current blocking selection diode matrix into the super backup capacitor element. The central storage chip is controlled to maintain power supply with the help of the capacitor to complete a power outage record. Thus, even if the auxiliary power supply link of the whole vehicle is eventually completely disconnected, maintenance personnel can still read the key status of this cutoff discharge in subsequent maintenance.

[0166] The purpose of this mechanism is to incorporate the load-side rebound energy, which may have caused shock and information loss at the moment of discharge cutoff, into the controlled path, thereby simultaneously achieving contact impact suppression, control log retention, and safe shutdown of the whole machine under low voltage conditions.

[0167] In this embodiment, after the delayed action window caused by the generation of the circuit breaker command ends, the system executes a cyclic takeover process, including:

[0168] After a preset quiet relaxation cooling time, the overall cycle scan is initiated through the dynamic evolution monitoring module to read the open-circuit static potential of all energy storage cells.

[0169] By comparing all open-circuit static potentials, a new selected energy storage cell with the smallest actual value is located and replaced with the previously compensated smallest voltage cell, serving as the target node for subsequent relay cycles.

[0170] This embodiment provides a target node cyclic takeover mechanism after multiple rounds of charge-disconnect compensation. Specifically, as described in the foregoing implementation, transient energy can be introduced into the current target node within a single circuit breaker delay action window. However, the target node should not remain fixed throughout its entire lifespan, because after several circuit breaker compensations, the original lowest voltage cell may have been improved, while other cells may become new low-voltage lagging cells. Therefore, this embodiment sets up a cyclic takeover process after the end of a single delay action window, so that the subsequent compensation target can be updated as the cell state changes.

[0171] Specifically, after the residual trigger module has completed the circuit breaker command, solid-state switch matrix selection, transient current pulse injection, and non-arc-induced degradation disconnection response after relay contact separation, the system does not immediately re-determine the target node, but instead enters a pre-set silent relaxation cooling time. This silent relaxation cooling time is used to wait for the individual cell voltage to fall back from the pulse disturbance and charging polarization state, so that the read potential is closer to the open-circuit static potential. The silent relaxation cooling time can be set from 30 seconds to several minutes, and the specific value can be calibrated according to the sodium ion cell capacity, the charging pulse intensity, and the vehicle operating conditions.

[0172] After the silent relaxation cooling time ends, the dynamic evolution monitoring module initiates an overall cyclic scan to read the open-circuit static potential of each energy storage cell in the energy storage cell matrix. Taking the aforementioned four-cell matrix as an example, if the initial target node is the second cell, after one or more compensations, the measured open-circuit static potential reading changes from the original combination of [3.22V, 3.20V, 3.23V, 3.21V] to the current sequence set data response of [3.25V, 3.24V, 3.26V, 3.23V].

[0173] The system releases the target lock on the initial minimum voltage cell, locates the fourth cell with the lowest current static terminal voltage through polling comparison, confirms it as the new minimum voltage cell, and updates it as the target node for the next equalization cycle according to the control command.

[0174] The cyclic takeover process does not conflict with the initial anchoring of the state anchoring module; the initial anchoring is used to confirm whether the entire group has the conditions for access and to establish the first round of target nodes during the power supply self-test period; the cyclic takeover is used to select the next round of compensation target based on the static potential of the open circuit end after the circuit breaker compensation has occurred; through this relay method, the system can avoid continuously injecting compensation pulses into the same cell and ignoring other low-voltage lagging cells, thus better meeting the dynamic balance requirements of the multi-cell matrix;

[0175] As an alternative control strategy, if a certain cell's potential still shows significant rebound oscillation after the quiet relaxation cooling time ends, the quiet time will be extended by one and the scan will be re-scanned; if a sampling channel is lost or fails to be verified during the overall cyclic scan, the target node will not be replaced, the redirection network will remain closed, and a sampling anomaly alarm will be issued; if the open-circuit static potentials of two or more energy storage cells are the same and are all at the minimum value, the energy storage cell that was not compensated in the previous round will be selected first. If it is still impossible to distinguish them, one of them will be selected according to the pre-set cell number order to ensure that the control logic is determined.

[0176] During a short-term power replenishment process at multiple stations on an intercity railway passenger train, the second unit continuously served as the target node in the first two power replenishment cycles. After pulse compensation at the moment of disconnection, its static potential gradually caught up. After the system re-scanned after the next quiet relaxation cooling time, it found that the fourth unit had become the new lowest potential unit. Therefore, the selection channel of the subsequent solid-state switch matrix was switched from the channel corresponding to the second unit to the channel corresponding to the fourth unit. Thus, the compensation action was carried out in relay between different low-voltage hysteresis units, rather than being fixed on the earlier initial lowest voltage unit for a long time.

[0177] It should be noted that the cyclic takeover process in this embodiment corresponds to the re-anchoring process after the delayed action window caused by the circuit breaker command during the charging phase ends. Its scanning object is the static potential of the open-circuit terminal of the energy storage unit matrix after transient compensation. The scenario in this embodiment corresponds to the log retention and safe exit process after the discharge cutoff. During the power supply maintenance period of the super backup capacitor element, the system prioritizes completing state preservation and orderly shutdown, and does not concurrently execute new target node switching during this short-term maintenance period. When the access conditions are met again and the charging process is re-entered, a new target node is activated based on the overall cyclic scan results after the silent relaxation cooling. Therefore, the discharge cutoff power preservation action and the cyclic takeover after the charging circuit breaker are sequentially connected and functionally independent, and will not conflict with the control objectives within the same time period.

[0178] The purpose of this step is to re-identify the actual low-voltage hysteresis cells after each circuit breaker compensation, so that the transient energy redirection network has the ability to periodically self-update, thereby improving the balancing efficiency in multiple charge-disconnect cycles and reducing the risk of local overcompensation caused by repeated compensation of a single cell.

[0179] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A sodium-ion battery charge-discharge equalization control system for railway passenger cars, comprising a main control unit connecting the main power grid and the passenger car equipment load; the main control unit connects a main circuit relay, an energy storage cell matrix, a magnetic flux-coupled transient energy redirection network, a super-reserve capacitor element, a high-frequency hardware comparator detection array, a control central storage chip, and a reverse-current blocking gating diode matrix; the main circuit relay includes a control coil and mechanical moving and stationary contacts; characterized in that, The magnetic flux-coupled transient energy redirection network is connected across the two ends of the main circuit relay, and its output is controlled to be connected to the energy storage unit matrix; the control main unit includes: State anchoring module: During the power supply self-test period, it acquires the initial voltage data of each energy storage cell, marks the cell with the lowest voltage as a specific target node, and controls the main circuit relay to close to connect to the main power grid when the data meets the preset access voltage range conditions; Dynamic evolution monitoring module: continuously collects voltage data of each energy storage cell during charging to construct a real-time voltage data set; Residual trigger module: Determines the comparison status of the set with the preset highest safety threshold, generates a command to be sent to the control coil to adjust the main circuit relay to maintain connection or disconnect; During the delayed action window period of the disconnect command cutting off the main power grid, controls the magnetic flux coupling transient energy redirection network to open the physical conduction path to the target node, and injects the residual inductance energy at the moment of disconnection into the target node unidirectionally for compensation. Discharge closed-loop module: During discharge, compare the total voltage of the entire system with the preset cutoff discharge threshold. At the instant the power supply network connected to the bus equipment load is cut off, capture the reactive rebound energy data of the load end and transfer it to the super backup capacitor element for storage.

2. The sodium-ion battery charge-discharge equalization control system for railway passenger cars according to claim 1, characterized in that, The magnetic flux coupled transient energy redirection network includes an inductive reactive wave-absorbing buffer branch and a multiplexed solid-state switch matrix. The inductive reactance absorbing buffer branch is connected in parallel to the two ends of the main circuit relay; The current input terminal of the multiplexed solid-state switch matrix is ​​connected to the inductive reactance absorbing buffer branch, and the branch output terminals of the multiplexed solid-state switch matrix are electrically connected in parallel to the two pole pins of each of the energy storage cells. The residual triggering module establishes the directional matching physical conduction path by manipulating a specific switch channel in the multiplexed solid-state switch matrix corresponding to the target node.

3. The sodium-ion battery charge-discharge equalization control system for railway passenger cars according to claim 2, characterized in that, The process by which the state anchoring module extracts the minimum voltage cell and marks the minimum voltage cell as the target node includes: Extract the steady-state static voltage value of each energy storage cell in the energy storage cell matrix within a preset monitoring time period; The preset voltage consistency tolerance threshold range is retrieved, and the maximum absolute difference between each of the static voltage steady-state values ​​is calculated to be configured as the full matrix limit deviation parameter. If the full matrix limit deviation parameter is less than the voltage consistency tolerance threshold range, then the associated energy storage cell with the smallest actual value is selected from each of the static voltage steady-state values, and the associated energy storage cell is established as the smallest voltage cell and marked as the target node accordingly. If the full matrix limit deviation parameter is greater than or equal to the voltage consistency tolerance threshold range, a matrix unit instability alarm signal is issued, and the main circuit relay is kept in the disconnection suppression state to prevent power supply.

4. The sodium-ion battery charge-discharge equalization control system for railway passenger cars according to claim 3, characterized in that, The process by which the residual triggering module determines the comparison status between the real-time voltage data set and the preset maximum safety threshold to generate a switching command includes: If all real-time voltage data in the real-time voltage data set are less than the maximum safety threshold, then the keep-connection command is generated to maintain the excitation current input to the main circuit relay control coil without decay, and the continuous power loading operation of connecting to the main power grid is executed. If at least one real-time voltage data point in the real-time voltage data set is greater than or equal to the highest safety threshold, then the circuit breaker command is generated to remove the excitation current for the control coil, and the energy transient transfer equalization process is activated for processing.

5. The sodium-ion battery charge-discharge equalization control system for railway passenger cars according to claim 4, characterized in that, The process of activating the energy transient transfer equalization process includes: Step 1: Record the pre-calibrated mechanical disconnection delay time constant between the issuance of the circuit breaker command and the physical separation of the mechanical moving contact from the stationary contact of the main circuit relay, and determine that the mechanical disconnection delay time constant is the delay action window period. Step 2: During the delayed action window, extract the parasitic inductance parameter data of the bus and the slope parameter of the sudden change in the instantaneous current of the bus, and calculate the peak value data of the induced electromotive force generated by the circuit breaker. Step 3: Control the switching action of the multiplexed solid-state switch matrix to close the physical conduction path of the target node. The peak value data of the induced electromotive force is reconstructed into transient current pulse data through the waveform trimming of the inductive reactance absorbing buffer branch. The transient current pulse data is applied to the target node in the lowest voltage state along the physical conduction path to perform forced current injection compensation. Step 4: Combining the peak-shaving effect of induced energy during the waveform trimming and reconstruction dissipation process, a non-arc-induced degraded disconnection response is completed at the contact separation surface of the main circuit relay.

6. The sodium-ion battery charge-discharge equalization control system for railway passenger cars according to claim 5, characterized in that, The process by which the dynamic evolution monitoring module continuously collects voltage data from each energy storage cell to construct a real-time voltage dataset includes: The parallel real-time channel feedback status of the high-frequency hardware comparator detection array is retrieved, and a continuous high-frequency sampling queue is established for all energy storage cell polarity interfaces. The real-time voltage data collected in the high-frequency sampling queue is extracted and spliced ​​to construct a voltage ramp-up time series of each energy storage cell as it gradually evolves over time during the charging process. Then, the voltage ramp-up time series is combined and reconstructed into a three-dimensional voltage distribution surface model that reflects the fluctuation of the overall energy storage cell matrix with the charging state over time.

7. The sodium-ion battery charge-discharge equalization control system for railway passenger cars according to claim 5, characterized in that, The process of calculating the peak value of the induced electromotive force generated by the circuit breaker includes: Acquire and analyze the parasitic inductance parameter data of the main power grid and connecting power cables under the power supply connection architecture as the parasitic inductance parameter data of the bus. Simultaneously extract the information of the instantaneous power supply current change rate of the total bus before the trigger point of the circuit breaker command execution as the instantaneous current sudden drop slope parameter of the bus. The peak value of the induced electromotive force, which characterizes the peak value of the induced polarization sudden voltage change, is obtained by multiplying the parasitic inductance parameter data of the bus with the slope parameter of the instantaneous current change and fall back of the bus.

8. The sodium-ion battery charge-discharge equalization control system for railway passenger cars according to claim 1, characterized in that, The process by which the discharge closed-loop module compares the total voltage across the entire system with the preset cutoff discharge threshold includes: Obtain the logical reversal request initiated by the external system based on the physical disconnection identification signal of the main power grid, and construct the discharge model flow direction of the system outputting reverse power supply current to the bus equipment load in reverse; Monitor the total system voltage reading output by the energy storage unit matrix, and execute a monitoring mechanism to determine whether the total system voltage reading is greater than the cutoff discharge threshold; If the comparison confirms that the total voltage reading of the entire system is greater than the cutoff discharge threshold, then the existing circuit for continuing to discharge to the load of the bus equipment is maintained. If the comparison confirms that the total voltage reading of the entire system is less than or equal to the cutoff discharge threshold, a low-level enable command is output to the control coil to control the main circuit relay to cut off the power supply network, and at the same time, the reactive power rebound capture and interception action is initiated on the load side of the bus equipment.

9. The sodium-ion battery charge-discharge equalization control system for railway passenger cars according to claim 8, characterized in that, The process of initiating reactive power rebound capture and interception actions targeting the load side of the bus equipment includes: Intercept the flyback reactive power echo electromagnetic inrush current data generated from the load side of the bus equipment at the instant the main circuit relay mechanical moving contact and stationary contact are disconnected due to the low-level enable command; When the instantaneous voltage generated by the flyback reactive echo electromagnetic inrush current is higher than the real-time terminal voltage of the super backup capacitor element, the reverse current blocking gating diode matrix is ​​naturally turned on due to forward bias as an introduction channel path, introducing and absorbing the flyback reactive echo electromagnetic inrush current data into the super backup capacitor element for storage and solidification. The energy stored in the super backup capacitor drives the central control storage chip to operate continuously to save the log of the power failure state before the circuit is disconnected, and finally cuts off the global power line interaction control within the whole system.

10. The sodium-ion battery charge-discharge equalization control system for railway passenger cars according to claim 9, characterized in that, After the delay window period triggered by the generation of the circuit breaker command ends, the system executes a cyclic takeover process, including: After a preset quiet relaxation cooling time, the dynamic evolution monitoring module initiates an overall cyclic scan to read the open-circuit static potential of all energy storage cells. By comparing all the open-circuit static potentials, a new selected energy storage cell with the smallest actual value is located and replaced with the previously compensated cell with the smallest voltage, serving as the target node for subsequent relay cycles.

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