A method, system and related devices for dynamic correction of charging terminal operating state

Abstract

The application discloses a charging terminal working state dynamic correction method, system and related device, which is used for delaying irreversible damage of terminal physical structure, prolonging the service life of the charging terminal while controlling the terminal temperature rise and maintaining the safe running state. The method comprises the following steps: extracting high-frequency ripples of a wide-frequency voltage signal and a wide-frequency current signal in a switching frequency band of a power converter, and calculating high-frequency transient AC impedance of the charging terminal; calculating a thermal drift amount of a terminal body resistance based on a temperature signal and a preset thermodynamic model, and stripping the thermal drift amount from the high-frequency transient AC impedance to obtain a real-time equivalent contact resistance; weightedly calculating a contact stability index; extracting a degradation acceleration representing a contact performance degradation trend; judging whether the terminal is in a contact performance degradation state according to the contact stability index and the degradation acceleration; if yes, generating a dynamic correction instruction to realize active intervention on the terminal temperature rise and the contact state.

Description

Technical Field

[0001] This application relates to the field of electrical technology, and in particular to a method, system and related apparatus for dynamically correcting the working state of a charging terminal. Background Technology

[0002] With the development of the electric vehicle industry, high-power DC fast charging technology has been widely used. DC fast charging mainly involves physically connecting the charging equipment side and the vehicle side's charging terminals to achieve the transmission of high voltage and high current.

[0003] In existing technologies, DC charging control typically employs a temperature threshold-based monitoring and protection mechanism. This involves placing temperature sensors, such as thermistors, inside the charging terminal body or its insulating base to collect real-time temperature data of the terminal area. When the vehicle controller or charging pile controller detects that the terminal temperature reaches a preset derating threshold, the system triggers a protection action, limiting or reducing the output current according to a preset fixed step ratio. When the monitored temperature reaches the ultimate safety threshold, the system directly cuts off the power output of the charging circuit.

[0004] However, due to the thermal resistance and thermal capacity characteristics of the heat conduction path of the terminal metal body and its surrounding structure, the temperature sensor's measurement feedback has a significant thermal inertia delay, causing the temperature data collected by the system to lag behind the actual transient temperature rise changes at the contact interface. Furthermore, the existing technology is a delayed intervention; within the time range where the contact performance of the charging terminal has deteriorated but the temperature has not yet reached the protection threshold, the system cannot implement proactive intervention. If the charging terminal operates in this sub-healthy state for a long time, it is prone to irreversible physical damage such as localized thermal ablation. Summary of the Invention

[0005] This application provides a method, system, and related apparatus for dynamically correcting the operating state of a charging terminal, which is used to delay irreversible damage to the physical structure of the terminal while controlling the temperature rise of the terminal and maintaining its safe operating state, thereby extending the service life of the charging terminal.

[0006] The first aspect of this application provides a method for dynamically correcting the operating state of a charging terminal, including:

[0007] Simultaneously acquire wideband voltage signals, wideband current signals, and temperature signals of the charging terminals in the DC charging circuit; Extract the high-frequency ripple of the wideband voltage signal and wideband current signal in the switching frequency band of the power converter, and calculate the high-frequency transient AC impedance of the charging terminal; The thermal drift of the terminal body resistance is calculated based on the temperature signal and the preset thermodynamic model, and the real-time equivalent contact resistance is obtained by stripping the thermal drift from the high-frequency transient AC impedance. Based on the offset rate and fluctuation dispersion of the real-time equivalent contact resistance relative to the reference value, and combined with the deviation between the measured temperature rise gradient and the theoretical temperature rise gradient, the contact stability index is calculated by weighting. The reference value is the real-time equivalent contact resistance during the initial connection stage of charging. Within a preset time window, the contact stability index of the continuous sequence is fitted with a second-order polynomial, and the coefficients of the quadratic term are extracted as the deterioration acceleration characterizing the contact performance degradation trend. The contact stability index and the degradation acceleration are used to determine whether the terminal is in a state of deteriorated contact performance. If so, a dynamic correction command is generated, and the charging current change rate or liquid cooling circuit flow rate is adjusted through feedforward control to achieve active intervention on terminal temperature rise and contact status.

[0008] A second aspect of this application provides a system for dynamically correcting the operating state of a charging terminal, comprising: The acquisition unit is used to synchronously acquire wideband voltage signals, wideband current signals, and temperature signals of the charging terminals in the DC charging circuit; The first calculation unit is used to extract the high-frequency ripple of the wideband voltage signal and wideband current signal in the switching frequency band of the power converter, and to calculate the high-frequency transient AC impedance of the charging terminal. The second calculation unit is used to calculate the thermal drift of the terminal body resistance based on the temperature signal and the preset thermodynamic model, and to obtain the real-time equivalent contact resistance by stripping the thermal drift from the high-frequency transient AC impedance. The third calculation unit is used to calculate the contact stability index by weighting the deviation rate and fluctuation dispersion of the real-time equivalent contact resistance relative to the reference value, combined with the deviation value between the measured temperature rise gradient and the theoretical temperature rise gradient. The reference value is the real-time equivalent contact resistance during the initial connection stage of charging. The extraction unit is used to perform second-order polynomial fitting on the contact stability index of the continuous sequence within a preset time window, and extract the coefficients of the quadratic term as the deterioration acceleration characterizing the contact performance degradation trend. The judgment unit is used to determine whether the terminal is in a state of deteriorated contact performance based on the contact stability index and the deterioration acceleration. The correction unit is used to generate a dynamic correction command when the judgment result of the judgment unit is yes, and to actively intervene in the terminal temperature rise and contact state by adjusting the charging current change rate or the liquid cooling circuit flow rate through feedforward control.

[0009] A third aspect of this application provides an apparatus for dynamically correcting the operating state of a charging terminal, the apparatus comprising: Processor, memory, input / output units, and bus; The processor is connected to the memory, the input / output unit, and the bus; The memory stores a program, which the processor calls to execute the first aspect and any optional method of dynamically correcting the operating state of the charging terminals.

[0010] The fourth aspect of this application provides a computer-readable storage medium storing a program that, when executed on a computer, performs the first aspect and any optional method of dynamically correcting the operating state of a charging terminal.

[0011] As can be seen from the above technical solutions, this application has the following advantages: By using the high-frequency ripple of the power converter of the charging device as the sensing excitation, the transient AC impedance of the terminal is calculated, and the influence of thermal drift of the metal body is deducted to obtain the equivalent contact resistance that reflects the microscopic changes of the charging terminal contact interface in real time. Furthermore, the deviation amplitude and fluctuation characteristics of the equivalent contact resistance and the measured temperature rise deviation are comprehensively processed to generate a contact stability index that quantifies the sub-health state of the terminal. Second-order curve fitting is performed in the time dimension to extract the degradation acceleration that reflects the degradation trend. Finally, the contact stability index and degradation acceleration drive the generation of dynamic correction commands. Before the terminal heating reaches the limit protection threshold, the charging current change rate or liquid cooling circuit flow rate is adjusted in advance through feedforward control, so that the charging system can actively intervene and adjust within the time range of terminal contact performance degradation.

[0012] By dynamically correcting the working state of the charging terminals, it is possible to effectively suppress local thermal ablation of the terminals and accelerated degradation of the contact interface. While controlling the temperature rise of the terminals and maintaining their safe operating state, it can delay irreversible damage to the physical structure of the terminals and extend the service life of the charging terminals. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 A schematic flowchart of an embodiment of the method for dynamically correcting the working state of the charging terminal provided in this application; Figure 2 A schematic flowchart of an embodiment of the method for dynamically correcting the working state of the charging terminal provided in this application, which calculates the high-frequency transient AC impedance of the charging terminal; Figure 3A schematic flowchart of an embodiment of the method for dynamically correcting the working state of charging terminals provided in this application, which calculates the real-time equivalent contact resistance; Figure 4 A schematic flowchart of an embodiment of the method for dynamically correcting the working state of charging terminals provided in this application, which calculates the contact stability index; Figure 5 A flowchart illustrating an embodiment of the method for dynamically correcting the working state of a charging terminal provided in this application, which determines whether the terminal is in a state of deteriorated contact performance. Figure 6 A schematic flowchart of an embodiment of the method for dynamically correcting the working state of the charging terminal provided in this application, which generates a dynamic correction instruction; Figure 7 A schematic diagram of an embodiment of the system for dynamically correcting the working state of the charging terminal provided in this application; Figure 8 A schematic diagram of an embodiment of the device for dynamically correcting the working state of the charging terminal provided in this application. Detailed Implementation

[0015] This application provides a method, system, and related apparatus for dynamically correcting the operating state of a charging terminal, which is used to delay irreversible damage to the physical structure of the terminal while controlling the temperature rise of the terminal and maintaining its safe operating state, thereby extending the service life of the charging terminal.

[0016] It should be noted that the method for dynamically correcting the working state of charging terminals provided in this application is applicable to various charging terminals and charging systems, especially in DC fast charging scenarios. The executing entity can be a charging controller or power distribution unit main control module deployed inside the DC charging equipment, or it can be an edge computing node specifically used for charging safety monitoring; no specific limitation is made here. Furthermore, the method steps of this application can be executed independently by the aforementioned single controller, or they can be executed collaboratively by the controller on the charging equipment side and the controller on the vehicle side through a charging communication network. Typically, the vehicle controller or battery management system interacts and collaborates with the controller on the charging equipment side to optimize the charging process, but the core dynamic correction task is generally executed by the controller on the charging equipment side. For ease of explanation, this application uses the controller on the charging equipment side as the single executing entity for description, but this should not be construed as a limitation on the scope of protection of this invention.

[0017] Please see Figure 1 , Figure 1 An embodiment of the method for dynamically correcting the operating state of the charging terminal provided in this application includes: 101. Synchronously acquire wideband voltage signals, wideband current signals, and temperature signals from the charging terminals in the DC charging circuit; In implementing this invention, it is first necessary to simultaneously acquire wideband voltage signals, wideband current signals, and temperature signals from the charging terminals in the DC charging circuit. In practical applications of high-power DC fast charging, the charging equipment and the new energy vehicle establish a physical connection through the charging terminals to form a DC charging circuit for energy transfer. This DC charging circuit not only carries the main DC component used for energy transfer, but also inevitably contains high-frequency electrical fluctuation components due to the high-frequency continuous operation of the switching devices inside the power converter of the charging equipment. Acquiring wideband voltage and current signals specifically means that the data acquisition hardware used has a high sampling frequency and a wide analog front-end bandwidth, so that the acquired signals can completely cover and retain the transient electrical fluctuation characteristics generated by the inherent high-frequency operation of the system in the DC charging circuit. By acquiring wideband signals, the controller can capture microscopic information that cannot be obtained by conventional low-frequency steady-state sampling.

[0018] While acquiring the aforementioned wideband electrical signals, the controller also needs to obtain temperature signals through temperature sensors placed around the charging terminals. Temperature signals effectively monitor the temperature rise of the charging terminals and their surrounding environment, preventing electrical safety issues caused by abnormal temperatures. Since the electrical contact state and thermodynamic heating state of the charging terminals constitute a highly coupled multi-physics interaction process, to ensure that subsequent algorithms have a time-matched reference for decoupling analysis of the terminal contact state, the acquisition of the aforementioned wideband voltage, current, and temperature signals must be strictly synchronized based on a unified system clock source.

[0019] 102. Extract the high-frequency ripple of the wideband voltage signal and wideband current signal in the switching frequency band of the power converter, and calculate the high-frequency transient AC impedance of the charging terminal. DC fast charging equipment relies on its internal power converter to convert high-voltage electrical energy into output. During normal operation of the power converter, the internal high-power semiconductor switching devices continuously switch on and off at a specific high frequency. This periodic switching action generates high-frequency electrical fluctuation components superimposed on the stable DC level of the DC charging main circuit. Based on this, the controller performs frequency domain feature extraction on the acquired wideband voltage and current signals, and selectively locks onto the high-frequency band corresponding to the switching frequency of the power converter, thereby separating the signal within this specific frequency band to obtain the high-frequency voltage ripple and high-frequency current ripple within the target frequency band. In existing conventional charging control logic, these ripple signals generated by switching actions are usually considered electromagnetic interference noise that should be filtered out by hardware circuitry. However, this embodiment converts them into a continuous detection excitation source, obtaining a source signal for impedance detection without adding an external high-frequency signal generator to the charging circuit.

[0020] After separating the high-frequency voltage ripple and high-frequency current ripple, the controller calculates the high-frequency transient AC impedance of the charging terminal based on the dynamic response relationship between the ripple voltage and ripple current. In the actual engineering environment of new energy vehicle charging, if the ratio of the total voltage drop to the DC current of the DC circuit is directly used to evaluate the terminal contact resistance, the calculation result will be severely interfered with by the complex electrochemical polarization internal resistance of the vehicle's power battery, the battery back electromotive force, and the DC voltage drop of the long charging cable. This causes the micro-ohm level changes in the physical contact resistance of the terminal to be completely masked by the overall system background voltage. Since the polarization characteristics of the power battery exhibit extremely low equivalent impedance characteristics under high-frequency AC excitation, this embodiment uses the ripple under a specific high-frequency band to calculate the AC impedance, which can effectively isolate and eliminate the interference caused by battery terminal voltage fluctuations and the long DC cable voltage drop, so that the calculated high-frequency transient AC impedance can accurately map the real electrical contact state of the physical mating interface of the charging terminal.

[0021] For high-frequency AC signals, the battery pack physically acts as a giant capacitor, exhibiting extremely low impedance to high-frequency AC power. Therefore, when the high-frequency ripple generated by the charging device flows through the charging circuit, the resulting high-frequency voltage drop is only related to the physical metal hardware (cables, terminal contacts) in the circuit, and is independent of the battery's current charge and chemical state. The high-frequency transient AC impedance calculated through the above steps is the true resistance presented solely by the physical structure of the terminals and cables after eliminating chemical battery interference. Therefore, it can reflect microscopic physical changes such as oxidation, wear, or mechanical loosening of the terminal surface plating. Through this calculation step, the controller can detect microscopic contact changes caused by poor contact or aging, eliminating interference from macroscopic DC load changes at the level of underlying electrical parameters, thus exhibiting higher sensitivity.

[0022] 103. Calculate the thermal drift of the terminal body resistance based on the temperature signal and the preset thermodynamic model, and obtain the real-time equivalent contact resistance by removing the thermal drift from the high-frequency transient AC impedance. In high-power charging scenarios, Joule heating is inevitable when the charging terminal transmits a large current. The metal substrate that makes up the charging terminal usually has a positive temperature coefficient. As the temperature of the overall structure increases, the inherent resistance of the terminal metal body itself will show a corresponding increase. This increase in intrinsic resistance caused by physical heating is the thermal drift of the terminal body resistance.

[0023] The high-frequency transient AC impedance calculated in step 103 is, in a physical sense, a macroscopic physical quantity. It includes not only the microscopic contact impedance characterizing the physical state of the mating interface but also the impedance drift component generated by the heating of the terminal body material. To eliminate the interference of temperature changes on the contact state assessment, the controller calls the synchronously acquired temperature signal and inputs it as a known parameter into a preset thermodynamic model. This preset thermodynamic model pre-characterizes the temperature response coefficient of the terminal's conductive substrate and the thermal conductivity distribution characteristics of the terminal's internal structure. It maps the local temperature data acquired by the sensor to the overall temperature rise distribution of the terminal body's metal material, thereby accurately calculating the thermal drift of the terminal body resistance under the current environment and load. Subsequently, the calculated thermal drift is subtracted from the total high-frequency transient AC impedance to obtain the real-time equivalent contact resistance.

[0024] Existing conventional monitoring technologies typically cannot distinguish between the natural increase in body resistance caused by normal terminal heating and the abnormal increase in contact resistance caused by wear of the contact surface plating or spring relaxation. This makes it easy for safety protection strategies to generate false alarms during normal high-current charging and temperature rise, or to miss alarms in the early stages of actual micro-motion wear. In this embodiment, step 103 introduces a thermodynamic dimension benchmark compensation to decouple the physical quantities of electrical contact from those of thermal conduction, completely eliminating the background impedance drift interference caused by high-power loads. This allows the final output real-time equivalent contact resistance to truly characterize the microscopic state of the physical mating between the charging device and the vehicle terminals.

[0025] 104. Based on the deviation rate and fluctuation dispersion of the real-time equivalent contact resistance relative to the reference value, and combined with the deviation between the measured temperature rise gradient and the theoretical temperature rise gradient, the contact stability index is calculated by weighting. The reference value is the real-time equivalent contact resistance in the initial connection stage of charging. During the initial handshake connection phase of each charging task, before the terminals are subjected to the deep thermal stress caused by the continuous high current, the controller records the real-time equivalent contact resistance at this time and sets it as a reference value. As the charging process progresses, the controller continuously calculates the deviation of the current real-time equivalent contact resistance from this reference value, i.e., generating the offset rate. In real-world scenarios, if the terminal metal plating is oxidized or the contact surface is severely worn, this offset rate will show a gradual upward trend, reflecting the microscopic reduction of the effective conductive area of ​​the contact interface. Simultaneously, the controller calculates the degree of discrete change in the real-time equivalent contact resistance over a specific observation period, i.e., obtaining the fluctuation dispersion. The fluctuation dispersion is mainly used to capture the microscopic loosening phenomenon caused by mechanical spring fatigue in the terminal during the mating state. For example, when the charging cable connected to the vehicle is blown by external wind or slightly touched by a person, if the internal mechanical clamping force of the terminal is insufficient, its real-time equivalent contact resistance will experience high-frequency and discrete electrical jitter.

[0026] In addition to electrical evaluation metrics, the controller also incorporates thermal gradient analysis. It calculates the measured temperature rise gradient of the terminal based on continuously collected temperature signals, representing the actual rate of temperature change over time. Simultaneously, the controller calculates the theoretical temperature rise gradient based on the actual charging current flowing through the terminal and the ambient temperature. This theoretical gradient represents the normal heating rate that the terminal should exhibit under perfectly healthy contact conditions and with good heat dissipation. The controller calculates the deviation between the measured and theoretical temperature rise gradients. A significant increase in this deviation indicates that the terminal is accumulating abnormal heat beyond normal Joule heating expectations, which is a direct thermodynamic characteristic of deteriorated contact performance.

[0027] By comprehensively analyzing the above-mentioned offset rate representing the increase in macroscopic impedance, the fluctuation dispersion representing the loosening of mechanical mating, and the deviation value representing the abnormal heating rate, and by assigning corresponding weight proportions for weighted calculation, a unified contact stability index is finally output.

[0028] 105. Within a preset time window, perform second-order polynomial fitting on the contact stability index of the continuous sequence, and extract the coefficients of the quadratic term as the deterioration acceleration characterizing the contact performance degradation trend. In real-world DC fast charging, the degradation of contact performance at charging terminals is typically not an instantaneous abrupt change, but rather a nonlinear, gradual evolution. Most existing safety monitoring solutions only focus on whether a single physical quantity exceeds a set static protection boundary at the current moment. This static, single-point monitoring logic is prone to control-level response lag at critical points where controller parameters deteriorate rapidly. To achieve more advanced state warnings, this embodiment maintains a preset time window during operation and constructs a continuous sequence of multiple contact stability indices calculated continuously at fixed intervals within this time window. A second-order polynomial curve fitting algorithm is then applied to the contact stability indices of this continuous sequence to construct a mathematical model that reflects the trajectory of contact state evolution over time.

[0029] Among the characteristic parameters of the second-order polynomial, the coefficient of the quadratic term mathematically represents the curvature change of the curve. Mapped to the physical scenario of charging terminal contact degradation, this coefficient directly reflects the acceleration of the change in the contact stability index. The controller extracts this quadratic term coefficient and uses it as the degradation acceleration. When the micro-contact interface of the charging terminal begins to expand due to continuous high current load, or when the mechanical clamping force begins to decay rapidly due to external cable tension, the value of this degradation acceleration will significantly increase positively. This allows the identification of the physical inflection point where the terminal's operating state changes from slow, slight degradation to accelerated deterioration.

[0030] 106. Determine whether the terminal is in a state of deteriorated contact performance based on the contact stability index and deterioration acceleration; The contact stability index, at the physical level, characterizes the overall deviation of the charging terminal contact interface at the current moment, reflecting the current health level of the charging terminal; while the degradation acceleration, in the time dimension, describes the severity of the evolution of this deviation, and can reflect the evolution trend of the charging terminal undergoing serious failure.

[0031] In actual high-power DC charging scenarios, due to physical differences in manufacturing tolerances and cumulative service life of different vehicle terminals, some charging terminals may exhibit conventionally high impedance during initial insertion and the initial stage of high current loading, leading to an increase in the calculated contact stability index. However, if the degradation acceleration remains gradual at this time, it indicates that the state is within the range of normal thermal expansion of the material or controllable static tolerance matching, and the controller can determine that the charging terminal has not experienced substantial contact performance degradation. Conversely, if the controller detects that the contact stability index is at an abnormal level, and at the same time, the degradation acceleration shows a significant upward trend, it physically means that the micro-contact points of the terminal contact interface are undergoing continuous and irreversible deformation due to thermal stress or mechanical fatigue. A positive feedback accumulation is forming between contact resistance heating and mechanical structure degradation. At this time, the controller can determine that the terminal has truly entered a state of contact performance degradation, and then execute step 107.

[0032] In summary, step 106 uses the contact stability index as the basis for condition assessment and the degradation acceleration as the verification condition for evolution trend, so as to achieve accurate diagnosis of whether the terminal is in a state of contact performance degradation, thereby providing a decision basis for subsequent active intervention.

[0033] 107. Generate dynamic correction commands and adjust the charging current change rate or liquid cooling circuit flow rate through feedforward control to achieve active intervention on terminal temperature rise and contact status.

[0034] Traditional charging protection mechanisms are typically passive, hysteresis-based feedback control. This means that power is cut off or the current is drastically reduced only when the temperature sensor detects that the terminal's absolute temperature exceeds the physical protection limit. This rigid control not only interrupts the charging process but also often causes irreversible thermal stress damage to the terminals by the time the action is triggered. This embodiment, however, proactively generates targeted dynamic correction commands when it determines that the terminals are in a state of deteriorated contact performance. These dynamic correction commands directly act on the underlying power or heat dissipation actuators of the charging system, encompassing both electrical regulation and thermophysical regulation. Specifically, in terms of electrical regulation, by dynamically changing the rate of change of the charging current, it directly intervenes in the transient surge of Joule heating at the source of heat, smoothing the application of electrical load to avoid further electrical shock to the micro-contact points. In terms of thermophysical regulation, for charging devices with active cooling architectures, by adjusting the flow rate of the liquid cooling circuit, it changes the heat exchange flux of the cooling fluid in advance, dissipating heat before abnormal heat accumulates and conducts to the terminal casing on a large scale.

[0035] By dynamically adjusting the rate of change of current or cooling flow rate in advance, proactive intervention and correction can be carried out before micro-contact deterioration evolves into macro-thermal runaway, enabling high-power charging systems to maintain continuous and stable power transmission to the maximum extent while ensuring the physical safety of the hardware.

[0036] In this embodiment, the transient AC impedance of the terminal is calculated by using the high-frequency ripple of the power converter of the charging device as the sensing excitation, and the influence of thermal drift of the metal body is eliminated to obtain the equivalent contact resistance that reflects the microscopic changes of the contact interface of the charging terminal in real time. Furthermore, the deviation amplitude and fluctuation characteristics of the equivalent contact resistance and the measured temperature rise deviation are comprehensively processed to generate a contact stability index that quantifies the sub-health state of the terminal. Second-order curve fitting is performed in the time dimension to extract the degradation acceleration that reflects the degradation trend. Finally, the contact stability index and degradation acceleration drive the generation of dynamic correction commands. Before the terminal heating reaches the limit protection threshold, the charging current change rate or liquid cooling circuit flow rate is adjusted in advance through feedforward control, so that the charging system can actively intervene and adjust within the time range of terminal contact performance degradation.

[0037] By dynamically correcting the working state of the charging terminals, it is possible to effectively suppress local thermal ablation of the terminals and accelerated degradation of the contact interface. While controlling the temperature rise of the terminals and maintaining their safe operating state, it can delay irreversible damage to the physical structure of the terminals and extend the service life of the charging terminals.

[0038] Please see Figure 2 According to some embodiments of the present invention, in step 102, the high-frequency ripple of the wideband voltage signal and wideband current signal in the switching frequency band of the power converter is extracted, and the high-frequency transient AC impedance of the charging terminal is calculated, including but not limited to the following: 201. Configure a digital bandpass filter synchronized with the switching frequency of the power converter to filter and extract wideband voltage and current signals, and obtain high-frequency voltage ripple sequences and high-frequency current ripple sequences. In actual operation, the DC charging circuit not only contains the DC component that carries energy, but also broadband noise such as background harmonics from the power grid and electromagnetic interference from surrounding equipment. To optimize power conversion efficiency, the power converter of some high-power charging equipment dynamically adjusts its switching frequency according to the current charging stage and load demand. Traditional hardware filtering circuits with fixed cutoff frequencies are prone to excessive attenuation of the target ripple signal or failure to filter out out-of-band noise when the power converter changes frequency.

[0039] Therefore, this embodiment employs a digital bandpass filter, a signal processing module based on a software algorithm. This filter only allows signals within a specific bandwidth to pass through, blocking signals in other frequency bands. In practical applications, the controller reads the current switching frequency from the underlying driver of the power converter in real time and updates this frequency synchronously with the center frequency of the digital bandpass filter. Thus, wideband voltage and current signals can be continuously input to the filter. The filter effectively removes zero-frequency DC components and out-of-band spurious noise, retaining only the electrical fluctuations caused by the high-frequency switching action of the power converter, thereby ensuring that the extracted high-frequency voltage ripple and high-frequency current ripple are undistorted. The filtered discrete data points are continuously arranged on the time axis, forming a high-frequency voltage ripple sequence and a high-frequency current ripple sequence.

[0040] 202. Use a digital phase-locked loop to extract the phase difference between the high-frequency voltage ripple sequence and the high-frequency current ripple sequence, and calculate the time-domain amplitude of the high-frequency voltage ripple and the high-frequency current ripple. In practical high-power charging circuits, the physical structure of the terminals and the long wires inevitably introduce parasitic inductance and capacitance, causing a phase difference in time between the high-frequency current and voltage signals. Therefore, after obtaining the high-frequency voltage ripple sequence and the high-frequency current ripple sequence, the controller needs to use a digital phase-locked loop (PLL) algorithm to extract the phase difference between them. A PLL is a closed-loop control technology capable of accurately tracking and locking the phase of signals. By inputting these two sets of high-frequency ripple signals into the PLL, the controller can calculate the phase difference between the voltage ripple and the current ripple, and in the process, resolve their time-domain amplitudes, i.e., the AC effective value or peak value of the ripple signal.

[0041] 203. The high-frequency transient AC impedance of the charging terminal is calculated by multiplying the ratio of the time-domain amplitude with the cosine value of the phase difference.

[0042] After obtaining the time-domain amplitude and phase difference of the high-frequency voltage ripple and current ripple, the controller calculates the ratio of the time-domain amplitude of the high-frequency voltage ripple to the time-domain amplitude of the high-frequency current ripple, and performs a product operation by combining the cosine value of the phase difference, and finally obtains the high-frequency transient AC impedance of the charging terminal.

[0043] Specifically, the ratio of time-domain amplitudes reflects the total apparent impedance of the local charging circuit in that high-frequency band. During actual charging, due to the parasitic inductance of the charging terminals and surrounding leads, these structures introduce an inductive reactance component when high-frequency current flows through them, causing the total apparent impedance obtained directly from the amplitude ratio to include inductive interference. Directly using the unprocessed apparent impedance to evaluate the terminal contact state may lead to misjudgment. Therefore, to eliminate these interferences, the controller calculates the cosine of the phase difference, which in AC signal processing represents the proportion of the purely resistive effective component in the total impedance vector. The controller multiplies the ratio of time-domain amplitudes by the cosine of the phase difference. This calculation process is equivalent to stripping the inductive reactance component from the total apparent impedance, retaining the real resistance component that accurately reflects the terminal contact state. Mathematically, this is equivalent to physically projecting the total apparent impedance, including inductive reactance, onto the purely resistive real axis on the impedance complex plane. This precisely isolates the imaginary inductive reactance component, retaining only the real resistance component that accurately characterizes the physical contact state and actual heating characteristics of the terminal mating interface—the high-frequency transient AC impedance of the charging terminal. In this way, the controller can accurately measure the microscopic physical state of the terminal contact surface, avoiding the influence of inductive reactance on the calculation results.

[0044] In this embodiment, by introducing projection decoupling operation based on the phase difference cosine value, the purely resistive electrical physical quantity is accurately filtered and extracted from the total impedance of the controller mixed with inductive reactance, so that the calculated impedance parameter can accurately reflect the microscopic physical state of the terminal contact surface.

[0045] Please see Figure 3 According to some embodiments of the present invention, in step 103, the thermal drift of the terminal body resistance is calculated based on the temperature signal and a preset thermodynamic model, and the real-time equivalent contact resistance is obtained by stripping the thermal drift from the high-frequency transient AC impedance, including but not limited to the following: 301. Based on the temperature coefficient of the conductive substrate of the charging terminal and the characteristics of the heat conduction path from the temperature signal acquisition point to the contact interface, a thermal resistance-capacitance network containing equivalent thermal resistance and equivalent thermal capacity is constructed as a preset thermodynamic model. In practical high-power DC charging equipment, due to physical limitations, temperature sensors are typically not directly mounted on the microscopic contact interface between the charging terminal and the vehicle socket. Instead, they are positioned around the periphery of the terminal body as temperature signal acquisition points. This results in a spatial gradient difference and a temporal conduction delay between the temperature actually measured by the sensor and the core temperature of the contact interface where Joule heating actually occurs. To eliminate this difference, this embodiment constructs a pre-defined thermodynamic model.

[0046] Specifically, the main structure of the charging terminal is typically made of a conductive metal substrate such as copper alloy. These materials have an inherent temperature coefficient, meaning their resistivity increases systematically with increasing internal temperature. Simultaneously, the physical distance heat travels from the contact interface to the temperature signal acquisition point, the material's cross-sectional area, and its thermal conductivity collectively determine the heat conduction path characteristics of this region. The controller converts these heat conduction path characteristics into parameters similar to resistive-capacitive elements in circuitry. The physical properties that impede heat transfer are calculated as equivalent thermal resistance, while the physical properties of the terminal material itself that absorb and store heat are calculated as equivalent thermal capacity. Using these equivalent thermal resistances and equivalent thermal capacitive capacitive capacitive networks, a thermal resistance-capacitive network capable of simulating the dynamic process of actual heat conduction can be constructed. This network serves as a preset thermodynamic model, thereby characterizing the resistance drift of the terminal's conductive substrate with temperature changes and reconstructing the physical characteristics of heat diffusion and attenuation within the terminal.

[0047] 302. The Joule heat power calculated from the real-time collected DC charging current is used as the heat source input to the preset thermodynamic model. The temperature rise distribution inside the terminal body is calculated in combination with the temperature signal, and the thermal drift of the terminal body resistance is calculated based on the temperature rise distribution and temperature coefficient. In actual high-power DC charging processes, DC charging currents of up to hundreds of amperes continuously flow through the charging terminals. This current overcomes the inherent physical resistance of the conductive substrate of the terminals, inevitably generating significant Joule heating. The controller converts the real-time DC charging current value into a corresponding continuous heating power, using this power as the internal heat source driving the thermodynamic evolution of the controller. This heat power is then input into the network model established in the previous steps, which includes equivalent thermal resistance and equivalent thermal capacity. Simultaneously, real-time temperature signals synchronously collected by sensors arranged around the terminals are used as dynamic boundary conditions for solving the thermodynamic network. The temperature rise distribution within the terminal body is calculated and deduced within the preset thermodynamic model. This temperature rise distribution maps the gradual temperature gradient process from the most intensely heated internal contact interface to the peripheral temperature measurement points.

[0048] After obtaining the actual temperature levels of each region inside the terminal, the controller, combined with the inherent temperature coefficient of the conductive substrate—that is, the physical property that the material resistance intrinsically increases with increasing temperature—calculates the additional resistance increment caused by uneven internal heating of the terminal structure. This additional resistance component is entirely caused by physical thermal effects, namely, the thermal drift of the terminal's body resistance.

[0049] 303. Based on the phase difference between high-frequency voltage ripple and high-frequency current ripple, calculate the real resistance component of the high-frequency transient AC impedance, and subtract the thermal drift from the real resistance component to obtain the real-time equivalent contact resistance.

[0050] In order to accurately quantify the physical properties that actually generate Joule heating and characterize the state of the contact surface, the controller can use the phase difference parameter calculated in step 202 to perform trigonometric function calculation on the high-frequency transient AC impedance, eliminate the inductive reactance component caused by parasitic inductance of physical form, and extract the real resistance component that characterizes electrical resistance.

[0051] Although the extracted real resistance component eliminates the interference of spatial morphology, it still belongs to the macroscopic superposition resistance. It includes not only the microscopic physical contact resistance of the terminal mating interface but also the intrinsic resistance increment caused by the natural heating of the terminal's metal material due to continuous high current. Therefore, it is necessary to subtract the thermal drift from the real resistance component to obtain the real-time equivalent contact resistance that characterizes the true microscopic state of the terminal mating interface.

[0052] In this embodiment, the resistive thermal drift of the terminal body due to temperature rise is calculated using an equivalent thermal resistance-capacitance network model and DC heating power, reducing the temperature conduction delay error between the external temperature measurement point and the internal contact interface. Simultaneously, the real resistance component of the AC impedance is extracted using phase difference to eliminate interference from parasitic inductance of the spatial structure. Finally, by subtracting the thermal drift from the real resistance, the actual equivalent contact resistance is separated, thus objectively reflecting the physical wear or relaxation state of the terminal contact interface and improving the accuracy of condition monitoring under high load conditions.

[0053] Please see Figure 4 According to some embodiments of the present invention, the contact stability index is calculated in step 104, including but not limited to the following: 401. Within the set sliding time window, calculate the ratio of the change in real-time equivalent contact resistance to the reference value calibrated in the initial connection stage as the offset rate, and calculate the ratio of the standard deviation to the mean of the real-time equivalent contact resistance within the sliding time window as the fluctuation dispersion. In this embodiment, the real-time equivalent contact resistance recorded during the initial connection phase of the current charging task is first extracted as a reference value. This reference value characterizes the initial background physical contact conditions under the current specific mating state. Then, the change in the real-time equivalent contact resistance within the current sliding time window relative to this reference value is calculated, and the change is divided by the reference value to obtain the ratio. This ratio is used as the offset rate.

[0054] In actual operating conditions, the offset rate characterizes the macroscopic degradation of the conductivity of the terminal contact interface over time, reflecting phenomena such as the slow increase in impedance caused by continuous oxidation of the plating or surface wear. Simultaneously, statistical calculations are performed on all real-time equivalent contact resistance samples included within the sliding time window, calculating the standard deviation and arithmetic mean of the data set within the time window. The ratio of the standard deviation to the mean is then used as the fluctuation dispersion. The fluctuation dispersion reflects the relative severity of the contact resistance fluctuations over a short time interval.

[0055] 402. Obtain the current charging current and the collected ambient temperature, and look up the theoretical temperature rise gradient through a pre-established heat source matching table; During DC charging, the natural heating rate of the terminals is not constant but dynamically depends on the amount of Joule heat generated internally and the heat dissipation conditions of the external environment. The current charging current flowing through the terminals determines the basic heating power, while the ambient temperature constitutes the natural boundary condition for heat transfer from the controller. The controller acquires the current charging current and the collected ambient temperature, and obtains the theoretical temperature rise gradient by looking up a pre-established heat source matching lookup table. This lookup table is pre-stored in the controller and records the normal temperature rise rate calibration data of the charging terminals under different combinations of current load and ambient temperature in a healthy state. The controller uses the real-time acquired charging current and ambient temperature as joint index parameters to look up this table, thereby obtaining the theoretical temperature rise gradient that the terminals should exhibit under the current operating conditions.

[0056] 403. Take the first time derivative of the temperature signal as the measured temperature rise gradient and subtract the theoretical temperature rise gradient to obtain the deviation value; In a physical sense, the first derivative of the continuously acquired temperature signal over time represents the actual rate of temperature change of the entire terminal, which is the measured temperature rise gradient. The controller calculates the difference between this measured temperature rise gradient and the aforementioned theoretical temperature rise gradient to obtain the corresponding deviation value. If additional impedance heating occurs inside the terminal due to oxidation of the contact surface or physical wear, its actual heating rate will deviate from the theoretical expectation, resulting in a corresponding increase in the deviation value.

[0057] 404. Perform a weighted summation of the offset rate, fluctuation dispersion, and deviation value to output the contact stability index.

[0058] By assigning weights to the above-mentioned characteristic data, the offset rate representing the increase in long-term resistance, the fluctuation dispersion representing the loosening of mechanical mating, and the deviation value representing the abnormal accumulation rate of heat are weighted and summed. This allows the dispersed characteristics of multiple physical fields to be fused and output as a quantifiable contact stability index, thereby comprehensively and objectively reflecting the overall contact health level of the charging terminal under high-power dynamic operating conditions.

[0059] In some specific embodiments, considering that each physical insertion and separation between the charging terminal and the vehicle socket causes frictional wear and stress accumulation on the conductive plating layer on the terminal surface and the internal mechanical spring at the microscopic level, the contact stability index can be calculated by combining the total number of historical insertion and removal cycles of the charging terminal. Specifically, the total number of historical insertion and removal cycles of the charging terminal is obtained, and the current wear cycle stage of the charging terminal is assessed based on this total number of cycles. A first weighting coefficient corresponding to the offset rate, a second weighting coefficient corresponding to the fluctuation dispersion, and a third weighting coefficient corresponding to the deviation value are configured according to the wear cycle stage. The offset rate, fluctuation dispersion, and deviation value are then multiplied individually by their respective first, second, and third weighting coefficients, and the results of each product are summed to output the contact stability index.

[0060] Specifically, the controller compares the total number of historical insertion and removal cycles with a pre-calibrated mechanical life threshold to determine the current wear cycle stage of the terminal, which typically includes the initial break-in stage, the intermediate stable operation stage, and the late fatigue aging stage. The potential failure physical characteristics exhibited by the terminal differ significantly depending on the physical aging stage. For example, in the intermediate stable operation stage of the terminal's service life, the main progressive degradation risk is the slow oxidation and wear of the contact surface plating. At this stage, abnormal temperature rise in thermodynamic dimensions and a slow increase in macroscopic static impedance are the core diagnostic features, thus allowing for larger values ​​for the first and third weighting coefficients. However, when the terminal enters the late fatigue aging stage due to excessive insertion and removal cycles, the mechanical clamping force of the internal springs weakens substantially. The contact interface is prone to high-frequency vibration when subjected to the weight of the charging cable or external wind disturbances. At this stage, the fluctuation dispersion characterizing transient instability becomes the core diagnostic feature, allowing for a targeted increase in the value of the second weighting coefficient and a corresponding decrease in the other two weighting coefficients. Finally, the extracted offset rate, fluctuation dispersion, and deviation value are multiplied by their respective matching weight coefficients, and the three product results are added together to obtain a highly comprehensive and quantitative contact stability index.

[0061] Please see Figure 5According to some embodiments of the present invention, in step 106, it is determined whether the terminal is in a state of deteriorated contact performance based on the contact stability index and the deterioration acceleration, including but not limited to the following: 501. Compare the real-time calculated contact stability index with the preset stability threshold. If the contact stability index is greater than the stability threshold, extract the degradation acceleration within the preset time window. The real-time calculated contact stability index is compared with a preset stability threshold. The stability threshold is a reference value pre-set within the controller to characterize the safe operating boundary of the terminal. If the comparison result shows that the contact stability index is greater than the stability threshold, it indicates that the current contact state of the terminal has deviated from the normal operating health baseline range. To further verify whether this deviation is a continuous physical degradation or an accidental data disturbance, the controller extracts the degradation acceleration within a preset time window to analyze the dynamic evolution trend of the contact state.

[0062] 502. If the deterioration acceleration is greater than zero within a continuous set period, the charging terminal is confirmed to be in a state of contact performance deterioration. Based on the numerical characteristics of the fluctuation dispersion, the failure mode is classified. When the fluctuation dispersion is greater than the preset fluctuation threshold, it is determined to be mechanical relaxation deterioration. When the fluctuation dispersion is not greater than the preset fluctuation threshold, it is determined to be coating wear deterioration.

[0063] If the degradation acceleration is greater than zero for a continuous set period, meaning the quadratic coefficient remains positive, it physically indicates that the rate of deterioration of the terminal contact interface is accelerating. When this condition is met, the controller determines that the charging terminal is in a state of contact performance degradation. This dual confirmation mechanism, combining the degree of deviation from the current state with the trend of state evolution, can effectively filter out single data jumps caused by transient fluctuations in the power grid or test sampling errors, thus improving the reliability of degradation determination.

[0064] In this embodiment, when it is determined that the terminal is in a state of contact performance degradation, failure mode classification is further performed based on the numerical characteristics of the fluctuation dispersion extracted in the previous steps. The fluctuation dispersion directly reflects the relative jitter of the contact resistance over a short period of time. The controller compares the current fluctuation dispersion with a preset fluctuation threshold. When the fluctuation dispersion is greater than the preset fluctuation threshold, it indicates that the terminal contact interface experiences a rise in macroscopic impedance accompanied by high-frequency electrical parameter jumps. This phenomenon is usually caused by stress fatigue of the mechanical clamping spring inside the terminal, resulting in insufficient contact force and microscopic physical displacement. Therefore, the controller classifies it as mechanical relaxation degradation. Conversely, when the fluctuation dispersion is not greater than the preset fluctuation threshold, it indicates that although the conductivity of the contact interface decreases, leading to an increase in impedance, the overall contact state is relatively stable, and no significant mechanical jitter has occurred. This physical phenomenon usually corresponds to uniform physical wear or continuous chemical oxidation of the conductive plating on the terminal contact surface. Therefore, the controller classifies it as plating wear degradation.

[0065] In this embodiment, by introducing fluctuation dispersion as a classification parameter, not only can the objective confirmation of the terminal deterioration state be achieved, but the specific physical causes of the deterioration can also be further distinguished, providing a specific classification basis for subsequent implementation of differentiated active intervention control.

[0066] Please see Figure 6 According to some embodiments of the present invention, a dynamic correction command is generated in step 107 to adjust the rate of change of charging current or the flow rate of liquid cooling circuit through feedforward control, including but not limited to the following: 601. Match the corresponding dynamic correction strategy based on the failure mode classification results to generate dynamic correction instructions; Since the underlying physical mechanisms and subsequent deterioration characteristics of abnormal terminal heating caused by different failure modes are significantly different, it is necessary to establish a classification intervention mechanism to match the corresponding dynamic correction strategy according to the failure mode classification results in order to generate dynamic correction instructions.

[0067] 602. When mechanical relaxation degradation is determined, the current slope reduction factor is calculated based on the degradation acceleration, and the current rise slope in the current charging demand curve is dynamically reduced through feedforward control. When mechanical relaxation degradation is identified, it typically manifests as a microscopic high-frequency relative displacement at the terminal contact interface. If the original high current and high ramp-up rate are maintained under this physical condition, the transient changes in current can easily trigger a local surge in Joule heating or even micro-arcs at unstable contact points. Therefore, the controller extracts the degradation acceleration characterizing the deterioration trend and converts it into a current slope reduction factor according to a preset mapping function. Through a feedforward control path, the controller directly applies this factor to the drive layer of the power converter, dynamically reducing the ramp-up rate of the charging current. This intervention method effectively mitigates the transient impact of the electrical load on the fragile contact interface without immediately cutting off the charging process, providing time for the natural dissipation of heat inside the terminal, thereby suppressing rapid thermal runaway caused by mechanical vibration.

[0068] 603. When it is determined that the coating is worn and deteriorated, or when the contact stability index continues to rise to the preset limit intervention threshold after the current rise slope is reduced, the current charging current peak value is locked, and the liquid cooling circuit flow rate is increased according to the preset control step.

[0069] The wear and degradation of the plating layer is due to the reduction in the conductive area of ​​the contact interface, leading to an increase in static impedance. Its heating characteristic is a continuous steady-state temperature rise. At this point, simply limiting the current rise slope is insufficient to solve the heat accumulation problem caused by the steady-state high current. Furthermore, if the slope suppression strategy implemented earlier to address mechanical relaxation fails to effectively curb the degradation trend, causing the contact stability index to approach the controller's set limit intervention threshold, it indicates that the terminal heating is nearing the physical safety boundary. In both cases, the controller first instructs the charging device to lock the current peak output current, preventing further load increases and limiting the maximum heating power at the source. Subsequently, it coordinates with the external cooling actuator to gradually increase the operating power of the internal liquid-cooled circulation pump according to a preset control step, increasing the liquid-cooled circuit flow rate. This forcibly increases the heat exchange flux between the contact terminals and the external environment, proactively establishing a new safe thermal equilibrium state before the device thermally melts, ensuring charging safety under extreme conditions.

[0070] The following provides a detailed description of the system for dynamically correcting the operating state of the charging terminal provided in this application. Please refer to [link / reference]. Figure 7 , Figure 7 Another embodiment of the system for dynamically correcting the operating state of the charging terminal provided in this application, the system includes: The acquisition unit 701 is used to synchronously acquire the wideband voltage signal, wideband current signal and temperature signal of the charging terminal in the DC charging circuit; The first calculation unit 702 is used to extract the high-frequency ripple of the wideband voltage signal and wideband current signal in the switching frequency band of the power converter, and to calculate the high-frequency transient AC impedance of the charging terminal. The second calculation unit 703 is used to calculate the thermal drift of the terminal body resistance based on the temperature signal and the preset thermodynamic model, and to obtain the real-time equivalent contact resistance by stripping the thermal drift from the high-frequency transient AC impedance. The third calculation unit 704 is used to calculate the contact stability index by weighting the deviation rate and fluctuation dispersion of the real-time equivalent contact resistance relative to the reference value, combined with the deviation value between the measured temperature rise gradient and the theoretical temperature rise gradient. The reference value is the real-time equivalent contact resistance in the initial connection stage of charging. Extraction unit 705 is used to perform second-order polynomial fitting on the contact stability index of a continuous sequence within a preset time window, and extract the coefficients of the quadratic term as the deterioration acceleration characterizing the contact performance degradation trend. The judgment unit 706 is used to determine whether the terminal is in a state of deteriorated contact performance based on the contact stability index and the deterioration acceleration. The correction unit 707 is used to generate a dynamic correction command when the judgment result of the judgment unit is yes, and to adjust the charging current change rate or the liquid cooling circuit flow rate through feedforward control to achieve active intervention on the terminal temperature rise and contact status.

[0071] In this embodiment, the functions of each unit are the same as described above. Figures 1 to 6 The steps in the method embodiments shown correspond to those in the examples, and will not be repeated here.

[0072] This application also provides a device for dynamically correcting the operating state of the charging terminal; please refer to [link / reference]. Figure 8 , Figure 8 One embodiment of the apparatus for dynamically correcting the operating state of the charging terminal provided in this application includes: Processor 801, memory 802, input / output unit 803, bus 804; The processor 801 is connected to the memory 802, the input / output unit 803, and the bus 804; The memory 802 stores a program, and the processor 801 calls the program to execute the method of dynamically correcting the working state of any of the charging terminals as described above.

[0073] This application also relates to a computer-readable storage medium storing a program that, when run on a computer, causes the computer to perform the method for dynamically correcting the operating state of any of the charging terminals as described above.

[0074] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0075] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between apparatuses or units, and may be electrical, mechanical, or other forms.

[0076] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0077] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0078] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for dynamically correcting the operating state of a charging terminal, characterized in that, The method includes: Simultaneously acquire wideband voltage signals, wideband current signals, and temperature signals of the charging terminals in the DC charging circuit; Extract the high-frequency ripple of the wideband voltage signal and wideband current signal in the switching frequency band of the power converter, and calculate the high-frequency transient AC impedance of the charging terminal; The thermal drift of the terminal body resistance is calculated based on the temperature signal and the preset thermodynamic model, and the real-time equivalent contact resistance is obtained by stripping the thermal drift from the high-frequency transient AC impedance. Based on the offset rate and fluctuation dispersion of the real-time equivalent contact resistance relative to the reference value, and combined with the deviation between the measured temperature rise gradient and the theoretical temperature rise gradient, the contact stability index is calculated by weighting. The reference value is the real-time equivalent contact resistance during the initial connection stage of charging. Within a preset time window, the contact stability index of the continuous sequence is fitted with a second-order polynomial, and the coefficients of the quadratic term are extracted as the deterioration acceleration characterizing the contact performance degradation trend. The contact stability index and the degradation acceleration are used to determine whether the terminal is in a state of deteriorated contact performance. If so, a dynamic correction command is generated, and the charging current change rate or liquid cooling circuit flow rate is adjusted through feedforward control to achieve active intervention on terminal temperature rise and contact status.

2. The method according to claim 1, characterized in that, The step of extracting the high-frequency ripple of the wideband voltage signal and wideband current signal within the switching frequency band of the power converter, and calculating the high-frequency transient AC impedance of the charging terminal, includes: A digital bandpass filter synchronized with the switching frequency of the power converter is configured to filter and extract the wideband voltage signal and the wideband current signal to obtain a high-frequency voltage ripple sequence and a high-frequency current ripple sequence. The phase difference between the high-frequency voltage ripple sequence and the high-frequency current ripple sequence is extracted using a digital phase-locked loop, and the time-domain amplitudes of the high-frequency voltage ripple and the high-frequency current ripple are calculated. The high-frequency transient AC impedance of the charging terminal is calculated by multiplying the ratio of the time-domain amplitudes with the cosine of the phase difference.

3. The method according to claim 2, characterized in that, The calculation of the thermal drift of the terminal body resistance based on the temperature signal and a preset thermodynamic model, and the extraction of the thermal drift from the high-frequency transient AC impedance to obtain the real-time equivalent contact resistance, includes: Based on the temperature coefficient of the conductive substrate of the charging terminal and the characteristics of the heat conduction path from the temperature signal acquisition point to the contact interface, a thermal resistance-capacitance network containing equivalent thermal resistance and equivalent thermal capacity is constructed as a preset thermodynamic model. The Joule thermal power calculated from the real-time collected DC charging current is used as a heat source input into the preset thermodynamic model. The temperature rise distribution inside the terminal body is calculated in combination with the temperature signal, and the thermal drift of the terminal body resistance is calculated based on the temperature rise distribution and the temperature coefficient. Based on the phase difference between the high-frequency voltage ripple and the high-frequency current ripple, the real resistance component of the high-frequency transient AC impedance is calculated, and the thermal drift is subtracted from the real resistance component to obtain the real-time equivalent contact resistance.

4. The method according to claim 1, characterized in that, The contact stability index is calculated by weighting the deviation rate and fluctuation dispersion of the real-time equivalent contact resistance relative to the reference value, combined with the deviation between the measured temperature rise gradient and the theoretical temperature rise gradient, including: Within the set sliding time window, the ratio of the change in the real-time equivalent contact resistance to the reference value calibrated in the initial connection stage is calculated as the offset rate, and the ratio of the standard deviation to the mean of the real-time equivalent contact resistance within the sliding time window is calculated as the fluctuation dispersion. The current charging current and the ambient temperature are obtained, and the theoretical temperature rise gradient is obtained by looking up a pre-established heat source matching table. The deviation value is obtained by subtracting the theoretical temperature rise gradient from the measured temperature rise gradient using the first time derivative of the temperature signal. The contact stability index is output by performing a weighted summation operation on the offset rate, the fluctuation dispersion, and the deviation value.

5. The method according to claim 4, characterized in that, The step of performing a weighted summation of the offset rate, the fluctuation dispersion, and the deviation value to output the contact stability index includes: Obtain the total number of historical insertion and removal cycles of the charging terminal, and evaluate the current wear cycle stage of the charging terminal based on the total number of historical insertion and removal cycles; Based on the wear cycle stage, configure a first weighting coefficient corresponding to the offset rate, a second weighting coefficient corresponding to the fluctuation dispersion, and a third weighting coefficient corresponding to the deviation value; The offset rate, the fluctuation dispersion, and the deviation value are each multiplied by their corresponding first weight coefficient, second weight coefficient, and third weight coefficient, and the results of each product are added together to output the contact stability index.

6. The method according to any one of claims 1 to 5, characterized in that, The step of determining whether a terminal is in a state of contact performance degradation based on the contact stability index and the degradation acceleration includes: The contact stability index calculated in real time is compared with a preset stability threshold. If the contact stability index is greater than the stability threshold, the degradation acceleration within the preset time window is extracted. If the degradation acceleration is greater than zero throughout the consecutive set period, the charging terminal is confirmed to be in a state of contact performance degradation. Failure mode classification is performed based on the numerical characteristics of the fluctuation dispersion. When the fluctuation dispersion is greater than a preset fluctuation threshold, it is determined to be mechanical relaxation degradation. When the fluctuation dispersion is not greater than the preset fluctuation threshold, it is determined to be coating wear degradation.

7. The method according to claim 6, characterized in that, The generation of dynamic correction instructions, which adjusts the rate of change of charging current or the flow rate of liquid cooling circuit through feedforward control, includes: The dynamic correction instruction is generated by matching the corresponding dynamic correction strategy based on the failure mode classification results. When mechanical relaxation degradation is determined, the current slope reduction factor is calculated based on the degradation acceleration, and the current rise slope in the current charging demand curve is dynamically reduced through feedforward control. When the coating is determined to be worn and deteriorated, or when the contact stability index continues to rise to a preset limit intervention threshold after the current rise slope is reduced, the current charging current peak value is locked, and the liquid cooling circuit flow rate is increased according to a preset control step.

8. A system for dynamically correcting the operating state of a charging terminal, characterized in that, The system includes: The acquisition unit is used to synchronously acquire wideband voltage signals, wideband current signals, and temperature signals of the charging terminals in the DC charging circuit; The first calculation unit is used to extract the high-frequency ripple of the wideband voltage signal and wideband current signal in the switching frequency band of the power converter, and to calculate the high-frequency transient AC impedance of the charging terminal. The second calculation unit is used to calculate the thermal drift of the terminal body resistance based on the temperature signal and the preset thermodynamic model, and to obtain the real-time equivalent contact resistance by stripping the thermal drift from the high-frequency transient AC impedance. The third calculation unit is used to calculate the contact stability index by weighting the deviation rate and fluctuation dispersion of the real-time equivalent contact resistance relative to the reference value, combined with the deviation value between the measured temperature rise gradient and the theoretical temperature rise gradient. The reference value is the real-time equivalent contact resistance during the initial connection stage of charging. The extraction unit is used to perform second-order polynomial fitting on the contact stability index of the continuous sequence within a preset time window, and extract the coefficients of the quadratic term as the deterioration acceleration characterizing the contact performance degradation trend. The judgment unit is used to determine whether the terminal is in a state of deteriorated contact performance based on the contact stability index and the deterioration acceleration. The correction unit is used to generate a dynamic correction command when the judgment result of the judgment unit is yes, and to actively intervene in the terminal temperature rise and contact state by adjusting the charging current change rate or the liquid cooling circuit flow rate through feedforward control.

9. A device for dynamically correcting the working state of a charging terminal, characterized in that, The device includes: Processor, memory, input / output units, and bus; The processor is connected to the memory, the input / output unit, and the bus; The memory stores a program, which the processor invokes to perform the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium contains a program that, when executed on a computer, performs the method as described in any one of claims 1 to 7.

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