A low voltage discharge power management system for a parallel dc power supply system

Abstract

The application discloses a low-voltage discharge power management system of a parallel direct-current power supply system, a bidirectional power module is used for performing discharge control on a discharge port, a cushioning power module is connected to the discharge port in a series mode and provides a cushioning voltage in a constant-voltage output mode, a PWM driving signal of the cushioning power module is adjusted through feedback control to maintain the cushioning voltage close to a target value of the cushioning voltage; a PWM fingerprint template library is built in a system controller, the cushioning power module is started when the discharge port enters a preset low-voltage interval, a flow-stopping observation window is entered and the constant-voltage output mode is maintained when a preset termination trigger condition is met, a PWM fingerprint sequence is formed by collecting the PWM driving signal, a PWM fingerprint feature is extracted, a low-voltage discharge in-place judgment result is generated by comparing the PWM fingerprint feature with a PWM fingerprint template, and the application solves the problem of unstable in-place judgment in a low-voltage discharge phase of a lithium battery.

Description

Technical Field

[0001] This invention relates to the field of battery low-voltage discharge and power management technology, and more specifically, to a low-voltage discharge power management system for a parallel DC power supply system. Background Technology

[0002] In lithium-ion battery formation and capacity testing, besides film formation and charging, a discharge process is often required at specified stages to bring the cells to the target state of charge or to verify consistency and controllability. Formation equipment typically uses a parallel DC power supply bus with multiple discharge channels to discharge multiple cells simultaneously. As the discharge enters the low-voltage range or even approaches zero voltage, the cell terminal voltage is already very low. At this point, the proportion of wiring harness resistance, fixture contact resistance, power circuit voltage drop, and sampling path error in the measured value increases significantly. This makes the port voltage easily pulled down by the circuit voltage drop, making it appear as if it has been lowered considerably, but the actual state of the cell may not be as low as it seems. Therefore, whether low-voltage discharge is complete becomes a frequent and easily contentious issue encountered on the formation site.

[0003] The rebound effect, common after low-voltage discharge, further amplifies the aforementioned uncertainties. Rebound refers to the rapid rise in port voltage from an extremely low value after the discharge current stops, followed by a slow increase and stabilization over a period of time. Its physical and chemical causes are usually a combination of factors: the port voltage contains a significant ohmic voltage drop component during discharge; when the current stops, it becomes zero, and this voltage drop disappears, resulting in a rapid rise; simultaneously, charge transfer polarization and double-layer effects exist at the electrode interface during discharge, and the interface quickly relaxes from equilibrium after the current stops; furthermore, a concentration gradient forms between the electrolyte and the active particles, and ion diffusion gradually returns to equilibrium after the current stops, leading to a slower voltage climb over a longer timescale. In the low-voltage range, because the cell's core voltage is very low, any disappearance of voltage drop and recovery of polarization will be more significant in the readings. This means that rebound after the current stops could indicate either a natural recovery within the cell or a false bottom caused by the previous low port voltage due to the circuit voltage drop, making it difficult to draw a stable conclusion based solely on the port voltage threshold or a fixed duration.

[0004] Existing technologies primarily focus on power supply / conversion availability and energy scheduling of multi-battery systems under low-voltage conditions. For example, CN107284259A, "DC Charging System and Charging Method for Low-Voltage Battery Systems," uses an auxiliary DC / DC converter to create a virtual voltage-induced charging pile, with the main DC / DC converter charging the battery system, primarily addressing the voltage range mismatch between the low-voltage battery system and the charging pile. Another example is CN109980741A, "An Active Balancing System for Battery Packs Based on Supercapacitors and Its Working Method," which achieves active balancing through a battery selection matrix, a bidirectional DC-DC constant current charging / discharging module, and a supercapacitor, focusing on energy transfer paths and balancing scheduling. While these solutions can improve charging adaptability or balancing capabilities under low-voltage conditions, they typically do not consider the rebound effect after low-voltage discharge as a criterion for determining whether discharge is complete, and lack a dedicated mechanism to distinguish the impact of the rapid jump caused by the disappearance of voltage drop during rebound and the slow climb caused by electrochemical recovery on the determination.

[0005] Therefore, in parallel multi-channel low-voltage discharge scenarios, there has long been a pain point in engineering that is easily overlooked but difficult to address: the readings in the low-voltage range are highly sensitive to loop voltage drop and channel differences, and the rebound after current interruption makes this sensitivity explicit, making it difficult to maintain consistency and traceability in arrival determination across different channels, different fixture states, and different wiring harness conditions. This problem is difficult to solve for two reasons: firstly, the rebound is the result of the superposition of electrochemical and loop effects, and it is difficult to reliably separate the causes by simply looking at the port voltage curve; secondly, the parallel operation of multiple channels amplifies the differences, and traditional threshold-based determination methods often cannot reliably identify false arrival, thus affecting the stability and consistency of the formation process. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a low-voltage discharge power management system for a parallel DC power supply system, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A low-voltage discharge energy management system for a parallel DC power supply system includes a parallel DC power supply bus, multiple discharge channels, and a system controller.

[0009] Each discharge channel includes a discharge port, a voltage sampling unit, a current sampling unit, a bidirectional power supply module, and a riser power supply module. The bidirectional power supply module is used to perform discharge control on the discharge port. The riser power supply module is connected in series to the discharge port and provides a riser voltage in a constant voltage output manner. It also adjusts its PWM drive signal through feedback control to maintain the riser voltage close to the target value. The system controller has a built-in PWM fingerprint template library.

[0010] The system controller is configured to: start the raised power module when the discharge port enters a preset low voltage range; stop the discharge control of the bidirectional power module and enter the current-stop observation window when the preset termination trigger condition is met, while keeping the raised power module in the constant voltage output mode; collect the PWM drive signal to form a PWM fingerprint sequence and extract the PWM fingerprint features within the current-stop observation window; compare the PWM fingerprint features with at least one PWM fingerprint template in the PWM fingerprint template library to generate a low voltage discharge completion determination result.

[0011] Preferably, the raised power supply module includes a power conversion unit, a filtering unit, a voltage sampling feedback unit, and a control unit. The power conversion unit includes a switching transistor and an inductor. The filtering unit includes a capacitor. The voltage sampling feedback unit is used to acquire the raised voltage and generate a feedback quantity. The control unit is used to generate the PWM drive signal based on the deviation between the feedback quantity and the target value of the raised voltage to drive the switching transistor.

[0012] Preferably, the discharge control of the bidirectional power module within the current-stop observation window is restricted to make the discharge current zero, and the voltage sampling unit also collects the port voltage within the current-stop observation window to form a rebound voltage sequence.

[0013] Preferably, the PWM fingerprint sequence includes duty cycle data collected within the stop-flow observation window at a preset sampling period.

[0014] Preferably, the PWM fingerprint features include duty cycle fall-off magnitude, duty cycle fall-off rate, bottoming time when the duty cycle reaches a preset lower limit, and duty cycle fluctuation magnitude.

[0015] Preferably, the PWM fingerprint template library includes at least one PWM fingerprint template, each of which includes a template feature vector and a template determination label; the system controller is configured to generate the template determination label based on a historical low-voltage discharge process, wherein the historical low-voltage discharge process includes performing a retest determination after a current-stop observation window, the retest determination being used to determine whether the low-voltage discharge of the corresponding discharge channel is in place or not in place, wherein the template determination label is determined by the result of the retest determination and is associated with the template feature vector corresponding to the historical low-voltage discharge process and stored in the PWM fingerprint template library.

[0016] Preferably, comparing the PWM fingerprint feature with the at least one PWM fingerprint template includes: performing a distance metric calculation on the PWM fingerprint feature and the template feature vector, selecting the target PWM fingerprint template with the smallest distance metric, and determining the template determination label of the target PWM fingerprint template as the low voltage discharge in place determination result.

[0017] Preferably, the system controller is configured to extract rebound features based on the rebound voltage sequence, the rebound features including the rapid jump amplitude at the moment of current interruption and the slow climb amplitude after current interruption; the system controller has a built-in rebound feature template library, the rebound feature template library includes at least one rebound feature template, and each rebound feature template includes a rebound template feature vector and a rebound template determination label.

[0018] Preferably, the system controller is configured to perform a comparison between the PWM fingerprint feature and the PWM fingerprint template library to obtain a first determination result, and a comparison between the rebound feature and the rebound feature template library to obtain a second determination result, and generate the low voltage discharge in place determination result based on the first determination result and the second determination result, wherein when the first determination result and the second determination result are consistent, the consistent result is determined as the low voltage discharge in place determination result, and when the first determination result and the second determination result are inconsistent, the result indicating that the discharge has not been completed is determined as the low voltage discharge in place determination result.

[0019] Preferably, the preset termination triggering condition includes at least one of the following: the port voltage reaches a preset low voltage threshold or the discharge current reaches a preset minimum discharge current threshold.

[0020] The advantage of this invention over existing technologies lies in its utilization of the rebound law after low-voltage current interruption. Specifically, within the current interruption observation window, the port voltage exhibits a recovery process that is initially fast and then slows down. Simultaneously, the power regulation unit generates an observable feedback adjustment trajectory to maintain constant voltage output. Furthermore, when the power supply module provides the raised voltage in a constant voltage output mode and maintains it close to the target raised voltage value, the rebound of the port voltage changes the feedback deviation, driving the power supply module to adjust the PWM drive signal. Compared to simply observing the port voltage, the PWM adjustment process transforms the deviation change caused by the rebound into a quantifiable timing characteristic, amplifying the rebound effect in the control domain. This makes it easier to distinguish between false arrival caused by channel voltage drop and true arrival caused by changes in the equivalent state of the battery terminals.

[0021] Based on the above principles, this invention acquires PWM drive signals within the current-stop observation window to form a PWM fingerprint sequence and extracts PWM fingerprint features. By comparing this sequence with templates in the PWM fingerprint template library, a low-voltage discharge completion determination result is generated. This eliminates reliance on a single voltage threshold or empirical duration for completion determination, allowing for more stable output through the repeatability of feedback control behavior. Furthermore, the raised power module employs a constant-voltage structure including switching transistors, inductors, capacitors, and a feedback control unit, ensuring a one-to-one correspondence between the PWM fingerprint and the constant-voltage maintenance process, enhancing the template's portability and reproducibility. Within the current-stop observation window, the discharge current is limited to zero while simultaneously acquiring port voltages to form a rebound voltage sequence. Rebound features such as fast jump amplitude and slow creep amplitude are extracted to construct a rebound feature template library, which is then consistently fused with the determination results of the PWM fingerprint template. When the two types of determinations are inconsistent, a conservative strategy is adopted to output "not in place," reducing the risk of misjudging as "in place." The template determination label is obtained from the retest determination results of historical low-voltage discharge processes and stored in association with the template feature vector, enabling the template library to be gradually calibrated according to process and equipment conditions, improving long-term operational robustness. Attached Figure Description

[0022] Figure 1 This is the overall system architecture diagram of the present invention;

[0023] Figure 2 This is a detailed working principle diagram of the raised power module of the present invention;

[0024] Figure 3 This is the main flowchart of the low-voltage discharge management system of the present invention;

[0025] Figure 4 This is a flow chart of the construction and training of the feature template library of this invention. Detailed Implementation

[0026] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0027] like Figure 1 As shown, the low-voltage discharge energy management system of the parallel DC power supply system of the present invention includes a parallel DC power supply bus, multiple discharge channels, and a system controller. The parallel DC power supply bus provides a unified DC energy interface for multiple discharge channels. Each discharge channel corresponds to one battery to be discharged or a group of batteries to be discharged, and each discharge channel is independently controlled, which facilitates the parallel formation equipment to achieve simultaneous discharge and independent judgment of multiple channels on the same bus.

[0028] In one embodiment, each discharge channel includes a discharge port, a voltage sampling unit, a current sampling unit, a bidirectional power supply module, and a raised power supply module. The discharge port is the electrical connection interface between the discharge channel and an external battery, and includes at least two connection points: a positive terminal and a negative terminal. The port voltage refers to the potential difference measured by the voltage sampling unit across the discharge port. The measurement point for the port voltage can be positioned near the port side of the clamp to reduce the impact of the additional voltage drop introduced by the wiring harness on the measurement. The current sampling unit is used to collect the discharge current of the discharge channel, which is the actual current corresponding to the current control quantity applied by the bidirectional power supply module to the discharge port.

[0029] To make the circuit layout clearer, in one embodiment, a bidirectional power supply module serves as the main power module of the discharge channel. Its electrical terminals are connected to the discharge port, and constant current discharge or current-limited discharge is achieved through control commands. The raised power supply module is connected to the discharge port in series. Series connection means that the output terminal of the raised power supply module is connected in series with the discharge port circuit, so that the equivalent operating voltage presented by the discharge port is equal to the superposition of the battery terminal voltage and the raised voltage. The purpose of this design is that when the battery voltage is very low in the low-voltage range, the controllable range or measurement resolution of the bidirectional power supply module itself is easily limited. The series-connected raised power supply module provides a controllable raised voltage, keeping the circuit in a more controllable and measurable operating range, thereby ensuring that the discharge process in the low-voltage stage is sustainable, observable, and measurable.

[0030] like Figure 2 As shown, the raised power module in this invention can be understood as a commercially available constant voltage source module or a DC-DC module capable of constant voltage output. Its constant voltage source principle is not based on a naturally constant voltage, but rather on continuously adjusting the power switch drive through feedback control to bring the output voltage close to the set target. Since the raised power module is connected in series to the discharge port, the equivalent load seen at its output terminal changes with the battery terminal voltage. When the battery voltage drops or rebounds after a current interruption, the raised power module needs to adjust its output capability to maintain the raised voltage close to the target value. Therefore, its PWM drive signal will produce an observable adjustment trajectory. This invention utilizes this point to amplify the low-voltage rebound effect in the control domain, forming a comparable PWM fingerprint sequence.

[0031] In one embodiment, the raised power module can be implemented using a commercially available 5V 3A constant voltage riser, which is a high-efficiency, low-ripple switching regulated constant voltage source. The raised power module consists of a control section and a power circuit section. The control section can be composed of a microcontroller, a PWM switching control chip, a sampling chip, and peripheral circuitry. The power circuit consists of a switching transistor, an inductor, and a capacitor. The feedback network consists of an operational amplifier, an RC network, and an ADC. After connecting to the discharge port, the raised power module enters a constant voltage control mode. The control chip drives the switching transistor at a fixed switching frequency, such as 570kHz, to reduce the size of the inductor and capacitor while maintaining efficiency.

[0032] During the constant voltage implementation process, the voltage sampling feedback unit continuously collects the raised voltage and sends it to the feedback terminal through a voltage divider network. The feedback terminal voltage maintains a corresponding relationship with the reference voltage inside the control chip. For example, when the reference voltage is 0.8V, by configuring the voltage divider resistors, the feedback terminal voltage is 0.8V when the raised voltage is 5V, thus forming a stable negative feedback. The control unit compares the feedback terminal voltage with the reference voltage to obtain the deviation signal, and generates a control quantity through an error amplification and compensation network, thereby adjusting the duty cycle of the PWM drive signal. The switching transistor is turned on and off at high speed under the control of the PWM drive signal. The inductor stores current and freewheels, and the capacitor smooths the voltage ripple. Together, the inductor and capacitor convert the pulse energy into a continuous DC output, stabilizing the raised voltage near the target value.

[0033] When load changes or battery voltage fluctuations cause a downward trend in the boost voltage, the feedback voltage decreases accordingly. Upon detecting this deviation, the control unit increases the PWM duty cycle, lengthening the on-time of the switching transistor and increasing the average inductor current, thus pulling the output voltage back to the set value. Conversely, when the boost voltage slightly increases, the feedback voltage rises, and the control unit decreases the PWM duty cycle, causing the output to fall back to the set value. This adjustment process is dynamic and continuous, ensuring that the boost voltage remains close to the target value even under conditions of loop voltage drop, port status changes, or battery voltage variations, and forming an observable adjustment trajectory within the PWM duty cycle sequence.

[0034] like Figure 3 As shown, the main process of low-voltage discharge power management in this invention is executed in the system controller. The system controller is used to coordinate the working status of each discharge channel and output the judgment result. A typical process includes stages such as low voltage triggering, heightening start-up, discharge termination triggering, current stop observation, PWM fingerprint extraction, template comparison and arrival determination.

[0035] During the low-voltage triggering phase, the system controller determines whether the discharge port has entered the preset low-voltage range based on the port voltage of the voltage sampling unit. When the port voltage is lower than the upper threshold of the low-voltage range, it can be determined that the low-voltage range has been entered. This upper threshold can be selected according to process requirements; in one embodiment, it ranges from 0.5V to 3.0V. If the equipment mainly faces the final stage of formation discharge, it can be set to 1.0V to 2.0V to balance distinguishability and stability. After entering the low-voltage range, the power supply module is activated, and the power supply module is controlled to output the raised voltage according to the target raised voltage value. The target raised voltage value can be selected based on the optimal controllable voltage window of the bidirectional power supply module; in one embodiment, it ranges from 1.0V to 5.0V, and commonly, it is set to 2.0V to 3.5V. This keeps the equivalent operating voltage of the low-voltage range within a region that is easy to sample and control, avoiding unnecessary energy consumption due to excessive raised voltage.

[0036] During the discharge termination triggering phase, the system controller determines whether preset termination triggering conditions are met. These preset termination triggering conditions include at least one of the following: the port voltage reaches a preset low voltage threshold or the discharge current reaches a preset minimum discharge current threshold. The preset low voltage threshold is used to limit the target voltage level at the end of the discharge, and in one embodiment, its value ranges from 0.0V to 0.5V. The preset minimum discharge current threshold is used to limit the discharge capacity to decay to an approximate stop state, and in one embodiment, its value ranges from 0.01A to 0.20A. Parameter selection typically follows two principles: first, it must match the capacity and discharge rate of the battery being measured, ensuring the threshold is within a measurable and stable range; second, it must match the measurement accuracy of the equipment, ensuring the threshold does not fall within the noise-dominated region.

[0037] After the preset termination trigger condition is met, the system controller stops the discharge control of the bidirectional power module and enters the current-stop observation window. Simultaneously, the elevated power module remains in constant voltage output mode to allow it to continuously adjust its PWM drive signal. The current-stop observation window exists to observe the rebound process of the port voltage after the discharge current is removed, and simultaneously observes the feedback adjustment trajectory of the elevated power module in response to the deviation caused by the rebound, thereby forming fingerprint information that can be used for judgment. The duration of the current-stop observation window can be selected according to the battery system and process cycle; in one embodiment, it ranges from 0.2s to 10.0s; if it is desired to cover both the fast jump and part of the slow climb process of the rebound, it can be taken as 1.0s to 5.0s.

[0038] How to measure voltage under current-stop conditions is one of the key aspects of this invention. Within the current-stop observation window, the discharge control of the bidirectional power module is limited to zero discharge current. The voltage sampling unit continues to acquire port voltage with high input impedance, forming a rebound voltage sequence. Since the input impedance of the voltage sampling unit is much greater than the loop impedance, the sampling process does not significantly load the battery. Therefore, the measured port voltage can be approximated as the voltage recovery process of the battery in an open-circuit or near-open-circuit state. The sampling period of the rebound voltage sequence can be consistent with or more dense than that of the PWM fingerprint sequence. In one embodiment, it can be 0.5ms to 20ms. At the low voltage end, 1ms to 5ms is commonly used to capture fast jump amplitudes.

[0039] Within the current-stop observation window, the system controller acquires the PWM drive signal to form a PWM fingerprint sequence and extracts PWM fingerprint features from the sequence. Since the power supply module operates in constant voltage output mode, the rebound causes changes in the port equivalent conditions. The control unit adjusts the PWM drive signal to maintain the raised voltage close to the target value, thus leaving a identifiable drop and fluctuation trajectory in the PWM fingerprint sequence. In one embodiment, the PWM fingerprint sequence includes duty cycle data acquired within the current-stop observation window at a preset sampling period. The preset sampling period can be consistent with the controller scheduling period; in one embodiment, it ranges from 0.5ms to 10ms.

[0040] PWM fingerprint features can be used to quantify the aforementioned adjustment trajectory. In one embodiment, the PWM fingerprint features include duty cycle fall-off magnitude, duty cycle fall-off rate, bottoming time when the duty cycle reaches a preset lower limit, and duty cycle fluctuation amplitude. The duty cycle fall-off magnitude can be obtained by the difference between the duty cycle at the start of the current-stop observation window and the lowest duty cycle within the window, reflecting how much adjustment the raised power module needs to release under rebound impact. The duty cycle fall-off rate can be obtained by dividing the duty cycle change in the initial stage of current-stop by the corresponding time, reflecting how quickly the rebound causes deviation. The bottoming time is the moment when the duty cycle first reaches the preset lower limit, characterizing whether the control quantity saturates rapidly. The preset lower limit can be the minimum controllable duty cycle that matches the PWM resolution, and in one embodiment, it can be 0.0 to 0.05. The duty cycle fluctuation amplitude can be obtained by the difference between the maximum and minimum duty cycle values ​​within the window, characterizing the degree of jitter in the control loop during the rebound process, which is more likely to occur when the contact is unstable or the loop voltage drop dominates.

[0041] During the template comparison and arrival determination stage, the system controller compares the PWM fingerprint features with at least one PWM fingerprint template in the PWM fingerprint template library to generate a low-voltage discharge arrival determination result. The PWM fingerprint template library stores tagged template feature vectors, enabling the system to maintain consistency in determinations across different channels, batches, and device states. Figure 4As shown, the template library can be constructed and trained using historical low-voltage discharge processes. Each PWM fingerprint template includes a template feature vector and a template determination label. The system controller generates the template determination label based on historical low-voltage discharge processes, which include a retest determination performed after the current-stop observation window. The retest determination is used to determine whether the low-voltage discharge of the corresponding discharge channel is in place or not. The template determination label is determined by the retest determination result and is associated with the template feature vector corresponding to that historical low-voltage discharge process and stored in the PWM fingerprint template library.

[0042] In engineering, the low-voltage discharge completion state is usually defined manually by operating conditions, and different processes have different acceptance criteria for completion. Some operating conditions focus more on whether the port voltage has been pulled close to 0, while others focus more on whether the rebound after current interruption has converged to a stable level. This invention does not limit a single definition of completion during the template library construction stage, but allows the system controller to retest and determine historical low-voltage discharge processes according to preset completion criteria and generate template determination labels, thereby ensuring that the template comparison output is consistent with the process criteria.

[0043] In one embodiment, the near-zero threshold is used as the positioning criterion. The system controller continuously samples the port voltage at the end of the discharge phase and uses a preset near-zero threshold as the positioning criterion. The preset near-zero threshold can be between 0.00V and 0.10V. To avoid false triggering caused by sampling noise and fixture jitter, a hold condition can also be set so that the port voltage does not exceed the preset near-zero threshold for a duration of 0.05s to 0.50s. If the voltage and duration requirements are met, the system is determined to be in position, and the corresponding PWM fingerprint feature is used as a template.

[0044] In a further embodiment, a retest determination may be included. The retest determination is performed after the first current-stop observation window ends. The system controller then controls the bidirectional power module to continue discharging with a small current. The retest discharge current level can be 0.02A to 0.30A, and the retest discharge duration can be 0.2s to 2.0s. During the retest discharge phase, it is determined again whether the port voltage can reach and meet the preset near-zero threshold and holding condition. If the retest discharge phase still cannot reach and meet the condition, it indicates that the PWM fingerprint corresponding to the first current-stop observation window was not generated in the near-zero condition, and the retest determination is incomplete. If the condition can be reached and met, the retest determination is complete, and the PWM fingerprint feature obtained in the first current-stop observation window is assigned a complete label and stored in the PWM fingerprint template library.

[0045] In another embodiment, the arrival caliber adopts a springback convergence definition, suitable for processes that do not force the port voltage to be close to 0, but rather focus on whether the recovery state after current interruption is stable. The system controller collects port voltage data within the first current interruption observation window to form a springback voltage sequence, extracts the fast jump amplitude at the moment of current interruption and the slow creep amplitude after current interruption, and determines arrival based on a preset convergence threshold. The preset convergence threshold can be selected according to the equipment noise floor and product consistency requirements; the fast jump amplitude threshold can be 0.02V to 0.20V, and the slow creep amplitude threshold can be 0.02V to 0.30V. Re-testing is performed using a repeated observation method. After the first current interruption observation window ends, the system controller first performs a short-term small-current discharge to restore a comparable end state, then re-enters the second current interruption observation window and collects the second springback voltage sequence and the second PWM fingerprint sequence. If the rapid jump and slow climb amplitudes of the second rebound voltage sequence decrease relative to the first and enter the preset convergence threshold range, and the duty cycle decline amplitude and bottoming time in the second PWM fingerprint feature show a convergence trend, it indicates that the rebound has stabilized and the feedback adjustment of the power supply module has entered a repeatable state, and the retest is judged as in place. If the rebound still does not converge or the PWM fingerprint feature shows a rapid bottoming and large fluctuation amplitude, the retest is judged as not in place. The final template judgment label is determined by the retest judgment result and is associated with the template feature vector corresponding to the first current stop observation window and stored in the PWM fingerprint template library, so that the label in the template library is consistent with the in place caliber adopted by the process.

[0046] Template comparison can be implemented using distance metric calculation. The system controller performs distance metric calculation on the PWM fingerprint features and template feature vectors, selects the target PWM fingerprint template with the smallest distance metric, and determines the template determination label of this target PWM fingerprint template as the low-voltage discharge in-place determination result. The distance metric can be Euclidean distance or weighted Euclidean distance, and the weight can be set according to the feature stability. In one embodiment, higher weights are given to bottoming time and fall amplitude to enhance sensitivity to false in-place. Since the feature vector dimension of the template library is limited, this comparison process has low computational load and is suitable for real-time operation of embedded controllers.

[0047] In a further embodiment, the system controller can also extract rebound features based on the rebound voltage sequence and construct a rebound feature template library to form a dual-evidence judgment with the PWM fingerprint template. The rebound features include the fast jump amplitude at the moment of current interruption and the slow creep amplitude after current interruption. The fast jump amplitude can be determined by the maximum increment of the port voltage within a short period after current interruption, which can be 0.01s to 0.20s; the slow creep amplitude can be determined by the change in port voltage within a longer period after current interruption, which can be 0.2s to 5.0s. The rebound feature template library includes at least one rebound feature template, and each rebound feature template includes a rebound template feature vector and a rebound template judgment label. The rebound template judgment label can also be determined by the retest judgment results of historical low-voltage discharge processes, ensuring that the label sources of the two types of templates are consistent, facilitating fusion judgment.

[0048] In one embodiment of the fusion judgment, the system controller performs a comparison between the PWM fingerprint feature and the PWM fingerprint template library to obtain a first judgment result, and performs a comparison between the rebound feature and the rebound feature template library to obtain a second judgment result. Based on the first and second judgment results, a low-voltage discharge completion judgment result is generated. When the two results are consistent, the consistent result is determined as the final judgment; when the two results are inconsistent, the result indicating incomplete completion is determined as the final judgment. The purpose of this strategy is to reduce the risk of false completion judgment, because at the low-voltage end, occasional changes in circuit voltage drop and contact state can easily lead to deviations from single evidence, while the consistency of dual evidence can improve the reliability of the judgment.

[0049] The above implementation methods cover all the key technical aspects, including parallel DC power supply buses, multiple discharge channels, bidirectional power modules, constant voltage output and PWM feedback regulation of elevated power modules, current-stop observation windows, PWM fingerprint sequences and feature extraction, PWM fingerprint template library construction and tag generation, distance metric comparison, rebound voltage sequence acquisition and rebound feature extraction, rebound feature template library, and dual-judgment fusion strategies. Those skilled in the art can make equivalent substitutions or engineering adjustments to the sampling period, window duration, threshold range, and distance metric form without altering the core concepts described above.

[0050] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A low-voltage discharge power management system for a parallel DC power supply system, characterized in that, Includes a parallel DC power supply bus, multiple discharge channels, and a system controller; Each discharge channel includes a discharge port, a voltage sampling unit, a current sampling unit, a bidirectional power supply module, and a riser power supply module. The bidirectional power supply module is used to perform discharge control on the discharge port. The riser power supply module is connected in series to the discharge port and provides a riser voltage in a constant voltage output manner. It also adjusts its PWM drive signal through feedback control to maintain the riser voltage close to the target value. The system controller has a built-in PWM fingerprint template library. The system controller is configured to: start the raised power module when the discharge port enters a preset low voltage range; stop the discharge control of the bidirectional power module and enter the current-stop observation window when the preset termination trigger condition is met, while keeping the raised power module in the constant voltage output mode; collect the PWM drive signal to form a PWM fingerprint sequence and extract the PWM fingerprint features within the current-stop observation window; compare the PWM fingerprint features with at least one PWM fingerprint template in the PWM fingerprint template library to generate a low voltage discharge completion determination result.

2. The low-voltage discharge power management system of the parallel DC power supply system according to claim 1, characterized in that, The raised power module includes a power conversion unit, a filtering unit, a voltage sampling feedback unit, and a control unit. The power conversion unit includes a switching transistor and an inductor. The filtering unit includes a capacitor. The voltage sampling feedback unit is used to acquire the raised voltage and generate a feedback quantity. The control unit is used to generate the PWM drive signal based on the deviation between the feedback quantity and the target value of the raised voltage to drive the switching transistor.

3. The low-voltage discharge power management system of the parallel DC power supply system according to claim 1, characterized in that, Within the current-stop observation window, the discharge control of the bidirectional power module is restricted to make the discharge current of the discharge channel zero. The voltage sampling unit also collects the port voltage of the discharge port within the current-stop observation window to form a rebound voltage sequence.

4. The low-voltage discharge power management system of the parallel DC power supply system according to claim 1, characterized in that, The PWM fingerprint sequence includes duty cycle data collected within the stop-flow observation window at a preset sampling period.

5. The low-voltage discharge power management system of the parallel DC power supply system according to claim 4, characterized in that, The PWM fingerprint features include duty cycle fall-off magnitude, duty cycle fall-off rate, the time it takes for the duty cycle to reach a preset lower limit and the duty cycle fluctuation magnitude.

6. The low-voltage discharge power management system of the parallel DC power supply system according to claim 1, characterized in that, The PWM fingerprint template library includes at least one PWM fingerprint template, and each PWM fingerprint template includes a template feature vector and a template determination label; The system controller is configured to generate the template judgment tag based on historical low-voltage discharge processes. The historical low-voltage discharge process includes performing a retest judgment after the current stop observation window. The retest judgment is used to determine whether the low-voltage discharge of the corresponding discharge channel is in place or not. The template judgment tag is determined by the result of the retest judgment and is associated with the template feature vector corresponding to the historical low-voltage discharge process and stored in the PWM fingerprint template library.

7. The low-voltage discharge power management system of the parallel DC power supply system according to claim 6, characterized in that, Comparing the PWM fingerprint feature with the at least one PWM fingerprint template includes: performing a distance metric calculation on the PWM fingerprint feature and the template feature vector, selecting the target PWM fingerprint template with the smallest distance metric, and determining the template determination label of the target PWM fingerprint template as the low voltage discharge in place determination result.

8. The low-voltage discharge power management system of the parallel DC power supply system according to claim 3, characterized in that, The system controller is configured to extract rebound features based on the rebound voltage sequence. The rebound features include the rapid jump amplitude at the moment of current interruption and the slow creep amplitude after current interruption. The system controller has a built-in rebound feature template library, which includes at least one rebound feature template. Each rebound feature template includes a rebound template feature vector and a rebound template determination label.

9. The low-voltage discharge power management system of the parallel DC power supply system according to claim 8, characterized in that, The system controller is configured to perform a comparison between the PWM fingerprint feature and the PWM fingerprint template library to obtain a first determination result, and a comparison between the rebound feature and the rebound feature template library to obtain a second determination result, and generate a low-voltage discharge completion determination result based on the first determination result and the second determination result, wherein when the first determination result and the second determination result are consistent, the consistent result is determined as the low-voltage discharge completion determination result, and when the first determination result and the second determination result are inconsistent, the result indicating incomplete completion is determined as the low-voltage discharge completion determination result.

10. The low-voltage discharge power management system of the parallel DC power supply system according to claim 1, characterized in that, The preset termination triggering condition includes at least one of the following: the port voltage of the discharge port reaches a preset low voltage threshold or the discharge current of the discharge channel reaches a preset minimum discharge current threshold.

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