Method and system for suppressing direct-current bus impulse current output by direct-current charger

Abstract

The invention belongs to the technical field of impact current suppression, and relates to a method and system for suppressing the impact current of a DC bus output by a DC charger, and the method comprises the following steps: collecting the output voltage of the DC bus and the required voltage of a vehicle side, and forming a voltage sequence; calculating the change rate and the pressure difference of the two; when the change rate exceeds a threshold value or the communication time sequence is discontinuous, entering voltage limiting constraint control; determining a limiting function according to the change rate and the voltage difference and updating a voltage reference value; adjusting the output voltage according to the updated reference value; and continuously executing voltage reference value updating and output adjustment until the output and the required voltage tend to be consistent, then exiting the voltage limiting constraint, and continuously performing dynamic adjustment according to the required voltage. According to the technical scheme, through dynamic monitoring and voltage difference constraint on the bus and the required voltage, voltage limiting adjustment and reference value smooth updating during sudden change are achieved, the impact current peak value is effectively restrained, and it is ensured that the voltage is stable, the current is limited, and the system operates stably.

Description

Technical Field

[0001] This invention belongs to the field of inrush current suppression technology, and specifically relates to a method and system for suppressing inrush current on the DC bus output of a DC charger. Background Technology

[0002] In existing technologies, the suppression of inrush current on the DC bus output of a DC charger typically relies on a pre-charging branch, a soft-start ramp, and a buffer energy absorption network. These methods limit the voltage rise rate and initial energizing current to meet the requirements of charging safety and device protection. However, existing suppression strategies often involve setting fixed control logic around the power-on phase, which is insufficient for adapting to electrical disturbances during operation and makes it difficult to maintain dynamic consistency between the bus side and the vehicle side under complex operating conditions.

[0003] In actual operation, the output contactor is prone to abnormal operation due to mechanical rebound, contact erosion, or vibration. At the same time, communication timing may jitter or be discontinuous for a short time, causing a mismatch between the vehicle-side demand voltage and the charger output reference. At this time, the control loop is prone to rapid switching between constant current and constant voltage, resulting in a sudden rise in bus voltage and an instantaneous increase in the voltage difference between the bus and the vehicle side, which brings a significant surge current. This, in turn, creates a high-stress impact on the power converter, bus capacitor, and contactor contacts, and induces protection malfunctions and charging interruptions.

[0004] Meanwhile, existing current surge suppression methods are mostly based on fixed thresholds and static limiting. Their control models have low sensitivity to the rate of change of output voltage, the rate of change of demand voltage on the vehicle side, and the voltage difference between the two. The adjustment process has limited adaptability to the intensity of disturbances. Moreover, the voltage loop and the current loop usually operate as parallel independent units, making it difficult to form synchronous constraints and dynamic coordination in sudden change scenarios. This leads to inconsistent control timing, and the bus voltage generates an overshoot superposition effect within a short time window, weakening the surge current suppression effect and reducing the system stability margin.

[0005] It is evident that existing technologies often suffer from problems such as severe bus voltage fluctuations, increased current surges, and decreased system dynamic stability during short-term disturbances. This is a shortcoming of existing technologies.

[0006] In view of this, it is very necessary to provide a method and system for suppressing the inrush current of the DC bus output of a DC charger in order to solve the above-mentioned defects in the prior art. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the prior art, such as severe bus voltage fluctuations, increased current surges, and decreased system dynamic stability during short-term disturbances, by providing a method and system for suppressing DC bus surge current at the output of a DC charger, thereby solving the aforementioned technical problems.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A method for suppressing inrush current on the DC bus output of a DC charger includes the following steps: The output voltage of the charger's DC bus and the demand voltage on the vehicle side are collected to form a voltage sequence; Calculate the rate of change of output voltage, the rate of change of demand voltage, and the voltage difference between demand voltage and output voltage based on the voltage sequence. When the rate of change of output voltage or the rate of change of demand voltage exceeds the preset threshold, or when communication timing becomes discontinuous, the voltage limiting constraint control state is entered. Under voltage-limited constraint control, the limiting function is determined based on the rate of change of output voltage, the rate of change of demand voltage, and the voltage difference, and the voltage reference value is updated accordingly. Adjust the output voltage according to the updated voltage reference value; The voltage reference value is continuously updated and the output voltage is adjusted until the output voltage and the required voltage are consistent. Then, the voltage limit constraint control state is exited, and the voltage reference value is updated and the output voltage is adjusted according to the required voltage.

[0009] By adopting the above technical solution, through dynamic monitoring and differential voltage constraint control of the DC bus output of the DC charger and the demand voltage on the vehicle side, the voltage limiting adjustment and smooth update of the reference value are realized when the bus output voltage shows a sudden trend. It can effectively suppress the peak inrush current caused by various factors such as abnormal contactor operation, discontinuous communication timing, sudden change in voltage rate, or dynamic load fluctuation when short-term disturbances occur, and meet the requirements of keeping the bus voltage stable, limiting the peak current inrush, and maintaining dynamic and stable operation of the system when short-term disturbances occur.

[0010] The system generates a voltage sequence by collecting the DC bus output voltage and the vehicle-side demand voltage, providing a real-time voltage state basis for the control system. This allows for continuous tracking and calculation of the relationship between the bus and vehicle ends. The calculation process calculates the output voltage change rate, the demand voltage change rate, and the voltage difference between the two, enabling the system to quantitatively judge voltage change trends. It also proactively triggers voltage limiting constraint control when the change rate exceeds limits or communication is discontinuous, thus mitigating the rate of increase in bus voltage in advance. Under voltage limiting constraints, a constraint function based on the change rate and voltage difference is used to adjust the voltage reference value, resulting in a non-linear response characteristic for the output voltage adjustment. This achieves flexible voltage limiting in the early stages of disturbances, preventing the generation of high-amplitude inrush currents. The updated voltage reference value continuously corrects the bus output, ensuring that voltage changes dynamically align with demand changes, forming a closed-loop stable regulation process. Once the bus voltage and demand voltage re-align, the system automatically exits voltage limiting constraint control and returns to normal operation, ensuring a smooth and stable energy transfer channel before and after disturbances. This achieves rapid suppression of inrush currents and a highly reliable dynamic response.

[0011] Preferably, the preset threshold is adaptively adjusted based on historical data through a learning-based trigger threshold model. The historical data includes at least one of voltage change trends, temperature characteristics, and communication delay characteristics during historical charging cycles.

[0012] This technical solution achieves the following technical effects by introducing a learning-based trigger threshold model to adaptively adjust the preset threshold: First, the learning-based trigger threshold model establishes a dynamic mapping relationship based on multi-dimensional data such as voltage change trends, temperature characteristics, and communication delay characteristics within historical charging cycles. This makes the preset threshold no longer dependent on fixed parameters, but can automatically correct the judgment boundary according to changes in ambient temperature, voltage fluctuation frequency, and communication delay. This ensures that the voltage limiting triggering process maintains reasonable sensitivity under different operating conditions, avoids excessively high thresholds leading to response lag, or excessively low thresholds causing false triggering, and improves judgment accuracy and operational reliability. Second, by converting historical data into threshold adjustment weights, the model learns the statistical law between the bus voltage change rate and the peak value of the inrush current, and forms a self-learning update mechanism in multiple charge and discharge cycles, so that the threshold can gradually approach the optimal range as the operating conditions change, ensuring that it can still enter the voltage limiting constraint control state in a timely manner in scenarios such as voltage surge, temperature rise or increased communication delay, and improving the ability to predict abnormal changes. Third, adaptive filtering and confidence correction mechanisms can be further introduced during the threshold update process to ensure that random noise and individual abnormal samples in historical data do not affect the overall threshold trend, maintain the long-term stability and robustness of the model, and realize the threshold evolution from static setting to dynamic learning, so that the system can maintain accurate and sensitive trigger response in different environments, and improve the adaptability and intelligence level of surge current suppression.

[0013] Preferably, the limiting function is a nonlinear differential pressure response function. The output value of the limiting function has a nonlinear relationship with the rate of change of the output voltage, the rate of change of the demand voltage, and the differential pressure. This nonlinear relationship imposes constraints on the update amplitude of the voltage reference value during the differential pressure change process.

[0014] This technical solution achieves the following technical effects by setting a nonlinear differential pressure response function to form a constraint mechanism: First, a nonlinear correspondence is established between the output value of the limiting function and the output voltage change rate, the demand voltage change rate, and the voltage difference. This makes the update amplitude of the voltage reference value no longer respond linearly proportionally, but exhibits a nonlinear decay characteristic when the voltage difference changes abruptly or the rate of change is abnormal. This automatically reduces the update rate of the reference value during the rapid voltage rise phase, limits the bus voltage ramp-up slope, and effectively suppresses the instantaneous generation of high-amplitude inrush current. Second, the nonlinear response function dynamically adjusts the constraint strength according to the pressure difference change trend. It maintains a low suppression coefficient when the pressure difference changes steadily and rapidly increases the suppression coefficient when the pressure difference rises suddenly. This gives the voltage reference value adjustment process a flexible buffer characteristic, avoids overshoot or oscillation in the control loop, improves the smoothness and dynamic stability of the voltage limiting process, and reduces the stress impact on capacitors and power devices. Third, the constraint effect of the limiting function enables the voltage reference value update and the differential pressure state to form a closed-loop feedback, allowing the control system to actively slow down the adjustment step size when the differential pressure increases and restore normal response when the differential pressure converges. This achieves adaptive and flexible adjustment of the voltage control loop, significantly improving the system's shock resistance and response accuracy under transient disturbances, and ensuring the synchronous consistency between the bus voltage and the vehicle demand voltage.

[0015] Preferably, the constraint function exhibits a linear response when the pressure difference is in a stable state of change, and a nonlinear response when the pressure difference is in a rapidly changing state.

[0016] This technical solution distinguishes between linear and nonlinear response modes under pressure difference changes, enabling the constraint function to possess dynamic response characteristics, thereby achieving the following technical effects: First, the limiting function maintains a linear response when the differential pressure is in a stable state of change, so that the voltage reference value can be updated at a constant ratio. This ensures that the control gain and output continuity are maintained when the bus voltage and the vehicle-side demand voltage change smoothly, avoiding excessive constraint or response lag in the system during normal charging, thereby ensuring the smoothness and accuracy of the power regulation process. Second, when the differential pressure is changing rapidly, the limiting function automatically switches to a nonlinear response mode, so that the update amplitude of the voltage reference value decreases nonlinearly with the increase of the differential pressure change rate. This effectively suppresses the overshoot of the bus voltage during the differential pressure surge phase, improves the damping characteristics of the control loop, prevents transient current surges caused by voltage changes, and enhances the system's ability to quickly suppress short-term disturbances. Third, by switching between stable and abrupt changes in response, the control system can achieve a dynamic adjustment strategy that balances sensitivity and robustness in different operating ranges, ensuring that energy transfer efficiency during normal operation and shock protection performance during abnormal disturbances coexist, thereby improving the adaptability of DC charger output bus voltage control and the overall stability of the system.

[0017] Preferably, the constraint function forms a constraint relationship with the output of the current feedback control loop, and the update magnitude of the voltage reference value is synchronously corrected according to the current feedback signal.

[0018] This technical solution establishes a constraint relationship between the limiting function and the current feedback control loop, achieving coordinated regulation of both voltage and current loops, and thus obtaining the following technical effects: First, the constraint function and the current feedback signal form a linkage constraint, so that the update of the voltage reference value no longer depends solely on the voltage change rate and voltage difference, but is synchronously corrected in combination with the current feedback. When the output current approaches the rated upper limit or transient fluctuations occur, the voltage adjustment amplitude is automatically reduced, thereby avoiding overshoot caused by single voltage control and realizing real-time coordination between voltage regulation and current load status. Second, when the current feedback control loop detects that the rate of change of current exceeds the set threshold, it can directly affect the output of the limiting function, so that the voltage control loop converges and updates the amount in advance during the high current surge stage, limits the rate of rise of bus voltage, prevents power devices from being subjected to excessive stress due to sudden current increase, and improves the electrical safety and dynamic robustness of the system. Third, by synchronously correcting the voltage reference value update amplitude, the voltage control and current control are transformed from parallel operation to a coupled and coordinated relationship. A unified dynamic constraint model is established, which ensures that the bus voltage and output current maintain a consistent trend when disturbances occur, improving the coordination and response consistency of the control loop. This enables bidirectional control of voltage and current in short-term impact scenarios, significantly improving the stability and energy transfer balance of the system.

[0019] Preferably, the voltage limiting constraint control and the current feedback control form a coordinated control link. When the coordinated control link detects a sudden change in the voltage difference, it synchronously updates the voltage reference value and the current reference value.

[0020] This technical solution establishes a collaborative control link between voltage limiting constraint control and current feedback control, enabling synchronous dynamic updates of voltage and current, and achieving the following technical effects: First, when the collaborative control link detects a sudden change in differential pressure, it simultaneously corrects the voltage reference value and the current reference value, so that the bus voltage adjustment and current regulation maintain time consistency, avoiding energy imbalance or instantaneous overshoot caused by single-loop delay, thereby achieving rapid linkage response during the stage of sudden increase in differential pressure, shortening the system stability recovery time, and improving the dynamic tracking accuracy under disturbance. Second, by establishing synchronous update logic between voltage limiting constraint control and current feedback control, the voltage control loop has the auxiliary constraint capability of the current side when the voltage difference changes suddenly, and the current control loop can also converge the output in advance according to the voltage change trend, forming a bidirectional driving collaborative feedback channel, thereby maintaining the stable operation of the system when voltage surge and current surge occur simultaneously, and improving the anti-disturbance and anti-surge performance. Third, the introduction of the collaborative control link means that the voltage and current control loops no longer operate independently, but form a unified control framework in the event of a sudden change in differential pressure. This enables joint adjustment and dynamic compensation of reference values, making the energy distribution process more continuous and coordinated, reducing phase deviation and control lag between voltage and current, and improving the overall efficiency of bus inrush current suppression and the real-time stability of the system.

[0021] As a preferred approach, the collaborative control link executes the control logic corresponding to the voltage control loop, current control loop, and contactor timing control loop respectively during the control process, and coordinates the updates by sharing control variables.

[0022] This technical solution achieves the following technical effects by executing the control logic of the voltage control loop, current control loop, and contactor timing control loop separately within the coordinated control link, and by using shared control variables to achieve coordinated updates: First, the collaborative control link establishes a unified variable interaction mechanism between the voltage loop, current loop, and contactor timing loop, so that the target quantities of each control loop are calculated synchronously within the same control cycle. By sharing differential pressure, current change rate, and timing state parameters, it ensures that the response direction of each control loop is consistent, avoids mutual cancellation or delay of control logic, and improves the time coordination and execution consistency of the overall control chain. Second, during the charging process, when the contactor operates or the communication timing changes, the contactor timing control loop can feed back the status quantity to the voltage loop and current loop in real time, so that the voltage limiting and current limiting commands can be dynamically adjusted according to the timing of the contactor closing or opening, preventing voltage surges or current surges caused by control delays or judgment deviations, and realizing cross-link timing adaptive control. Third, by coordinating updates through shared control variables, the collaborative control link forms a closed-loop regulation system under multi-loop interaction. The voltage, current, and contactor control units execute update commands based on the same data, reducing signal redundancy and control lag, and ensuring that the bus voltage and output current maintain a smooth transition during the contactor dynamic switching phase, thereby improving the system's response synchronization and operational stability.

[0023] Furthermore, the present invention also provides a DC charger output DC bus inrush current suppression system, comprising: The acquisition module is used to obtain the output voltage of the charger's DC bus and the required voltage on the vehicle side and form a voltage sequence; The calculation module is used to calculate the rate of change of the output voltage, the rate of change of the demand voltage, and the voltage difference between the demand voltage and the output voltage based on the voltage sequence. The determination module is used to determine whether to enter the voltage limiting constraint control state based on the rate of change of output voltage, the rate of change of demand voltage, and the continuity of communication timing, combined with a preset threshold. The control module is used to determine the limiting function and generate an updated voltage reference value based on the rate of change of the output voltage, the rate of change of the demand voltage, and the voltage difference under the voltage limiting constraint control state. The execution module is used to adjust the output voltage of the power converter according to the updated voltage reference value, and when it detects that the output voltage is close to the demand voltage, the control system exits the voltage limit constraint control state and continues to update the voltage reference value and adjust the output voltage according to the demand voltage.

[0024] By adopting the above technical solution, through the hierarchical collaborative operation of the acquisition module, calculation module, judgment module, control module and execution module, real-time monitoring of the voltage status of the charger output terminal and the vehicle side, dynamic judgment of voltage difference and execution of voltage limiting constraints can be realized. It can quickly enter the voltage limiting control state when the output voltage changes suddenly or the communication is abnormal, and dynamically correct the output voltage reference value of the power converter, thereby suppressing the sudden rise of the bus voltage and the current surge peak, and ensuring the system's operational stability and energy transfer continuity under short-term disturbances. The acquisition module provides voltage time-series data, which forms the basis for the calculation module to calculate the voltage change rate and voltage difference. The calculation module compares the voltage change rates at the output and demand ends in real time. The judgment module identifies the sudden change trend of the bus voltage based on the change rate and communication continuity and triggers voltage limiting control. Under the voltage limiting state, the control module determines the limiting function based on the voltage difference and change rate, and generates a constrained voltage reference value. The execution module adjusts the output of the power converter according to the updated reference value to keep the bus voltage and the demand voltage dynamically consistent. After the deviation converges, it exits the voltage limiting constraint, realizing smooth voltage recovery and closed-loop steady-state control of the system.

[0025] Preferably, the system also includes a learning threshold module, which is communicatively connected to the determination module and is used to adaptively adjust the preset threshold based on historical data. The historical data includes at least one of voltage change trends, temperature characteristics, and communication delay characteristics during historical charging cycles.

[0026] This system achieves the following technical effects by introducing a learning-based threshold module to adaptively correct the judgment threshold: First, the learning-type threshold module establishes a multi-dimensional feature mapping relationship based on the voltage change trend, temperature characteristics and communication delay characteristics in historical charging cycles, so that the judgment module can automatically adjust the threshold judgment boundary under different ambient temperatures, different communication rates and different load conditions, thereby maintaining a dynamic balance between judgment sensitivity and reliability, and avoiding response lag or false triggering caused by fixed thresholds. Second, through continuous learning and weight iteration of historical data, the threshold module can extract statistical patterns in long-term operation and achieve periodic optimization of the threshold based on the characteristics of charging frequency and voltage fluctuation. This enables the system to maintain stable entry and exit judgment criteria in complex scenarios such as high temperature, high frequency oscillation or unstable communication, thereby improving the accuracy and robustness of voltage limit control triggering. Third, confidence assessment and outlier filtering mechanisms can be introduced during the adaptive adjustment process to ensure that the threshold correction results are not affected by random fluctuations and transient noise, maintain the continuity and predictability of threshold changes, thereby realizing the transformation of threshold setting from static fixed value to dynamic learning, and improving the system's environmental adaptability and intelligence under long-term operating conditions.

[0027] Preferably, a coordination module is also included, which is connected to the control module and the execution module to form a nonlinear coordination control link, the nonlinear coordination control link including: The constraint function unit is used to perform a linear response when the pressure difference changes steadily and a nonlinear response when the pressure difference changes rapidly. The current feedback unit is used to correct the update magnitude of the voltage reference value based on the current feedback signal. The synchronous update unit is used to simultaneously update the voltage reference value and the current reference value when a sudden change in differential pressure is detected.

[0028] This technical solution constructs a nonlinear collaborative control link by setting up a collaborative module, thereby achieving joint coordination between voltage control and current control and obtaining the following technical effects: First, the collaborative module restricts the function unit to execute a linear response when the differential pressure changes steadily and a nonlinear response when the differential pressure changes rapidly, so that the voltage regulation process has adaptive flexibility. It maintains linear control accuracy under stable operating conditions and enhances the suppression capability under sudden operating conditions. Thus, it automatically weakens the adjustment step size during the stage of sudden rise in bus voltage or current surge, ensuring the continuity and safety of voltage and current change process. Second, the current feedback unit introduces the real-time current signal into the voltage reference value correction logic, enabling the voltage control loop to dynamically adjust and update the amplitude according to the rate of current change, achieving coordinated adjustment of bidirectional constraints. When the current approaches the upper limit or transient fluctuations occur, the voltage adjustment amount is automatically converged to prevent voltage overshoot or power device impact, thereby improving the robustness and response consistency of the system under high dynamic loads. Third, when the synchronous update unit detects a sudden change in differential pressure, it simultaneously corrects the voltage and current reference values, forming a parallel response path. This enables the collaborative module to complete the dual-loop synchronous update within milliseconds, avoiding the energy imbalance and impact superposition effect caused by single-loop delay. This significantly improves the transient stability and overall control coordination of the DC charger under sudden disturbances.

[0029] The beneficial effects of this invention are that by dynamically monitoring and controlling the voltage difference between the DC bus output of the DC charger and the demand voltage on the vehicle side, it can achieve voltage limiting adjustment and smooth update of reference value when the bus output voltage shows a sudden change trend. It can effectively suppress the peak inrush current caused by various factors such as abnormal contactor operation, discontinuous communication timing, sudden change in voltage rate, or dynamic load fluctuation when short-term disturbances occur, and meet the requirements of keeping the bus voltage stable, limiting the peak current inrush, and maintaining dynamic and stable operation of the system when short-term disturbances occur.

[0030] Furthermore, the design principle of this invention is reliable, the structure is simple, and it has a very wide range of application prospects.

[0031] Therefore, it is evident that the present invention has outstanding substantive features and significant progress compared with the prior art, and the beneficial effects of its implementation are also obvious. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 This is a flowchart of a method for suppressing inrush current on the DC bus output of a DC charger, provided by the present invention. Figure 2 This is a schematic diagram of a DC charger output DC bus inrush current suppression system provided by the present invention.

[0034] The module consists of 1. Acquisition module, 2. Calculation module, 3. Judgment module, 4. Control module, and 5. Execution module. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following implementation methods.

[0036] Example 1: like Figure 1 As shown in the figure, this embodiment provides a method for suppressing the inrush current on the DC bus output of a DC charger, which includes the following steps: Step S1: Collect the output voltage of the charger's DC bus and the required voltage on the vehicle side to form a voltage sequence; Step S2: Calculate the rate of change of the output voltage, the rate of change of the demand voltage, and the voltage difference between the demand voltage and the output voltage based on the voltage sequence. Step S3: When the rate of change of the output voltage or the rate of change of the demand voltage exceeds the preset threshold, or when communication timing becomes discontinuous, the voltage limiting constraint control state is entered. Step S4: Under the voltage limiting constraint control state, determine the limiting function based on the rate of change of output voltage, the rate of change of demand voltage, and the voltage difference, and update the voltage reference value; Step S5: Adjust the output voltage according to the updated voltage reference value; Step S6: Continuously update the voltage reference value and adjust the output voltage until the output voltage and the required voltage are consistent. Exit the voltage limit constraint control state, and continue to update the voltage reference value and adjust the output voltage according to the required voltage.

[0037] By adopting the above technical solution, through dynamic monitoring and differential voltage constraint control of the DC bus output of the DC charger and the demand voltage on the vehicle side, the voltage limiting adjustment and smooth update of the reference value are realized when the bus output voltage shows a sudden trend. It can effectively suppress the peak inrush current caused by various factors such as abnormal contactor operation, discontinuous communication timing, sudden change in voltage rate, or dynamic load fluctuation when short-term disturbances occur, and meet the requirements of keeping the bus voltage stable, limiting the peak current inrush, and maintaining dynamic and stable operation of the system when short-term disturbances occur.

[0038] Specifically, by collecting the DC bus output voltage and the vehicle-side demand voltage to form a voltage sequence, a real-time voltage state quantity basis is provided for the control system, enabling continuous tracking and calculation of the relationship between the bus and vehicle ends. In the calculation phase, the output voltage change rate, demand voltage change rate, and the voltage difference between the two are calculated, giving the system the ability to quantitatively judge voltage change trends. When the change rate exceeds the limit or communication is discontinuous, voltage limiting constraint control is actively triggered to reduce the rate of rise of the bus voltage in advance. Under voltage limiting constraint, a constraint function is established based on the change rate and voltage difference to adjust the voltage reference value, making the output voltage adjustment exhibit non-linear response characteristics. This achieves flexible voltage limiting in the early stages of disturbances, avoiding the generation of high-amplitude inrush currents. The bus output is continuously corrected based on the updated voltage reference value, keeping voltage changes dynamically consistent with demand changes, forming a closed-loop stable regulation process. When the bus voltage and demand voltage re-align, the voltage limiting constraint control automatically exits and returns to normal operation mode, ensuring a smooth and stable energy transfer channel before and after disturbances, thereby achieving rapid suppression of inrush currents and a highly reliable dynamic response of the system.

[0039] Hereinafter, steps S1 to S6 will be specifically described according to embodiments of this application.

[0040] In step S1, in order to effectively suppress the inrush current of the output DC bus, it is necessary to first monitor and prepare the key voltage quantities in real time before the charger is put into operation.

[0041] In this embodiment of the application, by continuously collecting the DC bus output voltage of the charger and the demand voltage on the vehicle side, the time correspondence between the two is established to form a voltage sequence, which provides basic data support for subsequent dynamic current limiting, voltage limiting and control strategies.

[0042] Specifically, during the charger's power-on phase, the bus-side output is typically connected to the DC bus capacitor bank via a power converter, while the vehicle-side voltage demand is calculated by the on-board charging control unit and transmitted in real-time via a communication interface. To obtain complete dynamic characteristics, the charger output voltage and the vehicle-side voltage demand need to be sampled synchronously. The sampling period is set according to the system control frequency, ensuring a strict correspondence between the collected results on the time axis. This synchronous sampling method ensures that the transient responses at the bus and vehicle ends can be accurately recorded during voltage surges or communication disturbances, providing a high-precision timing basis for subsequent calculations of the rate of change and voltage difference. For example, the sampling period can be set on the order of milliseconds, such as 10ms, to ensure complete capture of transient characteristics even under conditions with high voltage change rates.

[0043] The sampled signal enters the signal conditioning unit via an isolated measurement channel for amplification and filtering to eliminate high-frequency components caused by environmental noise and electromagnetic interference, and to ensure the smoothness and continuity of the sampled waveform. For example, digital low-pass filtering or moving average filtering can be used to suppress transient spike interference while retaining the main dynamic components. For example, the cutoff frequency of the filter can be set according to the switching frequency of the power converter, and can be in the range of one-tenth to one-twentieth of it, to balance response speed and anti-interference performance.

[0044] The filtered output voltage and demand voltage data are recorded in timestamp format to form a voltage sequence. and .in, Indicates at time The output voltage of the DC bus of the charger. This represents the demand voltage on the vehicle side at the same time point. The sampling points of the two correspond one-to-one on the time axis, forming a set of discrete-time voltage sequences that reflect the continuous-time variation relationship. ,in For continuous sampling time.

[0045] Furthermore, to avoid sampling deviations caused by contactor bounce, communication delays, or sensor response lags during the sampling process, this embodiment introduces a synchronous triggering mechanism into the sampling control logic. When the control unit issues a sampling command, the DC bus voltage detection channel and the communication receiving channel simultaneously enter the sampling state and latch the data using a unified time base. This method ensures that time-aligned voltage data can still be obtained even under system clock jitter or communication delays, thereby eliminating the error accumulation problem caused by sampling asynchrony.

[0046] To further improve sampling accuracy, temperature and electromagnetic compensation mechanisms can be implemented in the sampling channel. Since temperature rise in power devices and sampling resistors can lead to measurement deviations, a temperature sensor can monitor the temperature of the measurement nodes in real time and compensate for and correct the sampling results based on the temperature coefficient. For scenarios with strong electromagnetic interference, shielded sampling lines and differential amplification can be used to reduce the impact of common-mode noise. Through these methods, the acquired output voltage and the required voltage not only maintain continuity in time but also exhibit high consistency in amplitude accuracy, ensuring accurate judgment in subsequent control algorithms.

[0047] After data acquisition, the sampled voltage sequence needs to be recorded and cached in real time. For example, the cache can adopt a ring structure to ensure continuous data updates without frame loss during high-frequency sampling. The length of the historical sampling window is determined by the calculation cycle of the control algorithm and can cover several sampling cycles, enabling sliding window calculations in subsequent rate of change and differential voltage calculations. This sliding storage structure allows for the continuous output of the complete voltage change trajectory up to the current moment during system operation, providing support for real-time determination of the dynamic trend of the bus voltage.

[0048] In other embodiments of this application, in order to enhance data stability and prevent occasional outliers from affecting the calculation results, an outlier removal strategy can be introduced after data recording. Based on the statistical distribution characteristics of historical samples, abrupt values ​​or distorted samples can be automatically identified and replaced with the nearest mean, thereby ensuring that the formed time series is statistically continuous and differentiable, and meeting the calculation requirements for the rate of change.

[0049] Furthermore, during the acquisition of bus voltage and vehicle demand voltage, the communication interface status can also be included in the monitoring scope. When anomalies such as communication delay, frame loss, or period discontinuity are detected, the time point of the anomaly is recorded, and weight corrections are made in subsequent rate of change calculations to prevent abnormal data from interfering with trend judgment. This measure effectively avoids false abrupt changes caused by communication anomalies and improves the judgment accuracy and stability of the bus inrush current suppression algorithm.

[0050] Thus far, step S1 has completed the high-precision synchronous acquisition of the charger output voltage and the vehicle-side demand voltage, as well as the construction of the voltage sequence. Through real-time dynamic monitoring and anomaly compensation mechanisms, the data continuity and sampling robustness have been significantly improved, providing a reliable input basis for subsequent differential pressure calculation, rate of change judgment, and pressure limiting control.

[0051] In step S2, to identify the dynamic relationship between the charger output voltage and the vehicle-side voltage, it is necessary to calculate the rate of change of the output voltage, the rate of change of the demand voltage, and the voltage difference between the two voltages based on the voltage sequence data obtained in step S1. Through the quantitative calculation of these parameters, the changing trends of the bus voltage and the vehicle demand voltage at different time points can be accurately reflected, thus providing a basis for judgment in voltage limiting constraint control.

[0052] In this embodiment of the application, it is necessary to first process the acquired output voltage sequence. Vehicle-side demand voltage sequence Discretization is performed. Since the sampling times of the two sets of data correspond exactly, at each time step... The voltage change between adjacent sampling points can be calculated above:

[0053] in, This indicates the change in the charger's output voltage between adjacent sampling periods. This indicates the change in vehicle-side demand voltage between adjacent sampling periods.

[0054] To more intuitively reflect the rate of voltage change, the output voltage change rate and the demand voltage change rate can be calculated and defined as follows:

[0055] in, The rate of change of the output voltage. The rate of change of the required voltage, This represents the time interval between adjacent sampling points. Using this calculation method, the system can obtain the voltage change rate at the current moment within each sampling period.

[0056] Furthermore, in this embodiment, considering that measurement noise and voltage transients may cause discrete fluctuations in the calculation of the rate of change, a moving average filtering mechanism can be introduced during the calculation process to achieve dynamic smoothing of the rate of change. Specifically, by analyzing the most recent... The smoothed rate of change is obtained by weighting the rate of change results within each sampling period:

[0057] in, Indicates the length of the sliding window, for example, Five to ten sampling periods can be used to maintain response speed, effectively smooth noise, suppress the influence of high-frequency disturbances, and make the rate of change curve smoother and more stable, thereby improving the reliability of subsequent differential pressure judgment.

[0058] After the rate of change is calculated, in order to reflect the transient difference between the bus output voltage and the vehicle demand voltage, the voltage difference between the two is further calculated:

[0059] in, Indicates at time The instantaneous voltage difference between the vehicle-side voltage and the bus output voltage reflects the degree of voltage matching between the two sides, and its trend is used to determine whether there is a risk of sudden change in the system.

[0060] when If the voltage rises continuously in a short period of time or its growth rate exceeds a predetermined threshold, it indicates that the rate of increase of the charger's output voltage is not matched with the absorption capacity of the vehicle side, which may lead to the formation of inrush current; conversely, when the voltage difference is stable or gradually converges, it indicates that the system is in a dynamic equilibrium state and the energy transfer of the bus is stable.

[0061] In other embodiments of this application, to further improve the judgment accuracy, a hysteresis discrimination mechanism can be introduced when calculating the differential pressure. When the differential pressure change is within a set threshold range, the control logic remains unchanged; the control state is only updated when the differential pressure continuously exceeds the upper limit or falls below the lower limit threshold, thereby avoiding frequent triggering caused by measurement noise or transient disturbances and ensuring the stability and anti-jitter performance of the voltage limiting control process. For example, the voltage differential threshold can be set in the range of tens of volts according to the equipment level and safety requirements; the hysteresis width can be appropriately adjusted according to communication delay and sampling accuracy to avoid unnecessary repeated triggering.

[0062] Furthermore, the calculation of the rate of change and pressure difference is used not only to identify abrupt changes but also to characterize the voltage response inertia of the system. For example, when Significantly higher than and During synchronous expansion, it can be determined that the output voltage rise rate is too fast, requiring voltage limiting constraint control to reduce the bus voltage ramp-up rate; while when Higher than At this time, it may be a response phase where the vehicle-side demand voltage rises rapidly, in which case normal control mode can be maintained. By comparing and determining the rates of change on both sides, the system can identify potential impact risks in the early stages and achieve preventative control.

[0063] In other embodiments of this application, in order to avoid over-responding to a single abnormal sampling, an anomaly suppression mechanism can also be introduced during the calculation process. When the rate of change in a certain period deviates from the average of the most recent multiple periods by more than a set multiple, the data point will be marked as an anomaly and participate in the confidence correction calculation. The corrected rate of change result participates in the average calculation through weight decay to prevent the mutation sample from misleading the overall trend judgment, thereby ensuring that the control triggering logic is based on the real dynamic trend rather than transient noise.

[0064] Through the above calculations, real-time values ​​and trend information of output voltage change rate, demand voltage change rate and voltage difference can be obtained in each control cycle. These data are continuously transmitted to the subsequent voltage limit constraint judgment stage to identify the sudden change trend of bus voltage and energy imbalance state.

[0065] Thus, in step S2, through discretization, rate of change calculation, sliding smoothing, voltage difference calculation, and hysteresis determination of the voltage sequence data, high-precision extraction of the dynamic characteristics of the voltage at the charger output and the vehicle side is achieved, providing a solid computational foundation for the intelligent triggering of the voltage limiting constraint and the active suppression of the inrush current.

[0066] In step S3, in order to achieve early identification of the sudden change trend of the bus voltage and feedforward suppression of the inrush current, it is necessary to determine whether to enter the voltage limit constraint control state based on the output voltage change rate, demand voltage change rate and communication status calculated in step S2. When the output voltage change rate or demand voltage change rate exceeds the preset threshold, or when a discontinuity in the communication timing is detected, it is determined that there is a sudden change risk, and then the voltage limit constraint control state is entered to limit the rise rate of the bus voltage and stabilize the energy transfer process.

[0067] Specifically, the rate of change of the output voltage can be measured in each sampling period. Demand voltage change rate Combined with communication status signals, a threshold for the output voltage change rate is set. The threshold for the rate of change of demand voltage is The communication continuity identifier quantity is When communication is normal When communication is abnormal or the delay exceeds the allowable range The control logic is as follows: When any of the following conditions are met:

[0068] or

[0069] or

[0070] This triggers the pressure limiting constraint control state. For example, and It can be set to 10V / ms.

[0071] This judgment logic comprehensively considers two scenarios: abnormal voltage change rate and communication discontinuity. The former is used to detect sudden characteristics of voltage changes, while the latter is used to identify system uncertainties caused by communication jitter or frame drops. When the voltage change rate suddenly increases, the energy release rate on the bus side may not match the absorption capacity on the vehicle side; and when the communication signal is discontinuous, the real-time update of the vehicle side's required voltage fails, and the control system loses effective tracking of the target value. Both situations can lead to a sharp increase in voltage difference and the formation of inrush current. Therefore, when either of the above conditions is met, it is necessary to immediately switch to the voltage limiting constraint state to suppress further rise in bus voltage.

[0072] In some embodiments of this application, to avoid false triggering caused by transient noise or individual data anomalies, a continuous determination mechanism can be set before entering the pressure limit constraint control, that is, continuous determination is required. The voltage limiting state can only be confirmed if the above conditions are met within a sampling period. The continuous time length can be set according to the control period and the system response speed. For example, if the control period is 1ms, the continuous judgment period can be 3 to 5 sampling periods, that is, the sudden event is confirmed within a few milliseconds, thereby ensuring the response speed while avoiding misjudgment of instantaneous disturbances.

[0073] In some embodiments of this application, to enable the voltage limiting trigger threshold to have adaptive capability, a learning-based trigger threshold model can be introduced to adjust the preset threshold. , Dynamic correction is performed. The model learns and updates the threshold based on the statistical patterns of historical operating data. Historical data includes at least one of the following: voltage change trends during historical charging cycles, ambient temperature characteristics, and communication delay characteristics. Its core idea is to establish a threshold adjustment function through multi-dimensional input features, so that the sensitivity of voltage limiting triggering is automatically optimized under different operating conditions.

[0074] Specifically, the input features of a learned thresholding model can be represented as a vector:

[0075] in, This represents the average ambient temperature during historical operation. This indicates the average variation in bus voltage over past charging cycles. This indicates the average duration or fluctuation characteristics of communication delay.

[0076] The model establishes a mapping relationship between feature vectors and the optimal threshold:

[0077] in, To learn the function, the output is The adaptive threshold corresponds to the current operating conditions.

[0078] Through this learning mechanism, the system can dynamically adjust the trigger boundary according to the environment and operating status. For example, when the temperature rises or the communication delay increases, the overall system response speed decreases, and the threshold is lowered accordingly to enter the pressure-limiting state earlier; conversely, under low temperature or stable communication conditions, the system can appropriately increase the threshold to avoid frequent triggering of the pressure-limiting constraint. This adaptive adjustment strategy ensures that the system can maintain reasonable trigger sensitivity and anti-interference capability under different external environments and operating conditions.

[0079] This step, by introducing a learned trigger threshold model to adaptively adjust the preset threshold, achieves the following technical effects: First, the learning-based trigger threshold model establishes a dynamic mapping relationship based on multi-dimensional data such as voltage change trends, temperature characteristics, and communication delay characteristics within historical charging cycles. This makes the preset threshold no longer dependent on fixed parameters, but can automatically correct the judgment boundary according to changes in ambient temperature, voltage fluctuation frequency, and communication delay. This ensures that the voltage limiting triggering process maintains reasonable sensitivity under different operating conditions, avoids excessively high thresholds leading to response lag, or excessively low thresholds causing false triggering, and improves judgment accuracy and operational reliability. Second, by converting historical data into threshold adjustment weights, the model learns the statistical law between the bus voltage change rate and the peak value of the inrush current, and forms a self-learning update mechanism in multiple charge and discharge cycles, so that the threshold can gradually approach the optimal range as the operating conditions change, ensuring that it can still enter the voltage limiting constraint control state in a timely manner in scenarios such as voltage surge, temperature rise or increased communication delay, and improving the ability to predict abnormal changes. Third, adaptive filtering and confidence correction mechanisms can be further introduced during the threshold update process to ensure that random noise and individual abnormal samples in historical data do not affect the overall threshold trend, maintain the long-term stability and robustness of the model, and realize the threshold evolution from static setting to dynamic learning, so that the system can maintain accurate and sensitive trigger response in different environments, and improve the adaptability and intelligence level of surge current suppression.

[0080] Furthermore, to prevent threshold drift caused by abnormal data, a confidence correction mechanism can be introduced during the threshold update process. This mechanism assigns lower weights to outliers in the historical sample set (such as communication interruptions or extreme temperature samples) and retains only high-confidence samples for threshold calculation. At the same time, the model can also perform incremental updates after each charging cycle, so that the threshold gradually converges to the statistically optimal range during multi-cycle operation.

[0081] In this embodiment, the running cycle of the learning model can be synchronized with the charging cycle, and the model parameter update frequency can be set according to the amount of sampled data and computing power to achieve a balance between computational complexity and real-time performance. For example, after each charging task is completed, the data of the previous cycle can be statistically analyzed and updated to enable the model to continuously optimize the threshold boundary, thereby achieving stable performance and adaptive evolution under long-term operation.

[0082] Thus, step S3 not only achieves rapid identification and voltage limiting triggering of sudden events, but also establishes an adaptive triggering mechanism by introducing a learning threshold model, enabling the system to maintain stable response sensitivity and anti-interference capability under various operating conditions. This significantly improves the robustness and intelligence of voltage limiting constraint control, providing an accurate and dynamic triggering basis for subsequent limit function calculation and voltage reference value update.

[0083] In step S4, after entering the voltage-limiting constraint control state, in order to achieve flexible constraint on the rate of rise of the bus voltage and dynamic suppression of the inrush current, it is necessary to determine the limiting function based on the real-time data of the output voltage change rate, the demand voltage change rate, and the voltage difference, and use this limiting function to update the voltage reference value. The limiting function plays a core regulatory role; its output value determines the adjustment amplitude and direction of the voltage reference value, enabling the bus voltage to respond smoothly and gradually converge during abrupt changes, thereby effectively preventing transient impacts caused by sudden voltage rises.

[0084] Specifically, upon detecting the entry into the voltage-limiting constraint state, the constraint function calculation phase will be initiated, using the output voltage change rate within the current sampling period. Demand voltage change rate and pressure difference The output coefficients of the constraint function are calculated in real time, using the input variables as input variables. This coefficient is used to constrain the update step size of the voltage reference value, thereby dynamically limiting the rate of rise of the bus voltage during the disturbance phase.

[0085] In this embodiment, the constraint function is defined as a nonlinear differential pressure response function, the mathematical expression of which is as follows:

[0086] Among them, the function It is a nonlinear mapping function, and its output value is... Used to impose limits on the amount of voltage reference value updates.

[0087] This step, by setting a nonlinear differential pressure response function to form a constraint mechanism, achieves the following technical effects: First, a nonlinear correspondence is established between the output value of the limiting function and the output voltage change rate, the demand voltage change rate, and the voltage difference. This makes the update amplitude of the voltage reference value no longer respond linearly proportionally, but exhibits a nonlinear decay characteristic when the voltage difference changes abruptly or the rate of change is abnormal. This automatically reduces the update rate of the reference value during the rapid voltage rise phase, limits the bus voltage ramp-up slope, and effectively suppresses the instantaneous generation of high-amplitude inrush current. Second, the nonlinear response function dynamically adjusts the constraint strength according to the pressure difference change trend. It maintains a low suppression coefficient when the pressure difference changes steadily and rapidly increases the suppression coefficient when the pressure difference rises suddenly. This gives the voltage reference value adjustment process a flexible buffer characteristic, avoids overshoot or oscillation in the control loop, improves the smoothness and dynamic stability of the voltage limiting process, and reduces the stress impact on capacitors and power devices. Third, the constraint effect of the limiting function enables the voltage reference value update and the differential pressure state to form a closed-loop feedback, allowing the control system to actively slow down the adjustment step size when the differential pressure increases and restore normal response when the differential pressure converges. This achieves adaptive and flexible adjustment of the voltage control loop, significantly improving the system's shock resistance and response accuracy under transient disturbances, and ensuring the synchronous consistency between the bus voltage and the vehicle demand voltage.

[0088] Furthermore, the design principle of this function is: when the voltage difference is small and the change is stable, the voltage reference value is allowed to be updated linearly; while when the voltage difference suddenly increases or the rate of change exceeds the threshold, the update rate is automatically reduced, forming a nonlinear constraint response.

[0089] Specifically, when the pressure difference is in a steady state, the linear response relationship of the constraint function can be expressed as:

[0090] in, Based on control gain, This is the linear adjustment coefficient. When the differential pressure changes slowly, the update rate is approximately linearly related to the differential pressure, which can ensure that the bus voltage maintains a smooth transition within the normal operating range and does not introduce excessive constraints.

[0091] When the rate or magnitude of pressure difference change exceeds a set threshold, the limiting function can switch to a nonlinear response mode to enhance the pressure limiting constraint strength. The nonlinear response relationship can be expressed as:

[0092] in, and This is a nonlinear attenuation coefficient that controls the influence of pressure difference and rate of change on the constraint function. Therefore, when the pressure difference or rate of change increases rapidly, the denominator term increases accordingly. The value is significantly reduced, thereby decreasing the update range of the voltage reference value, limiting the rate of rise of the bus voltage, and achieving flexible voltage limiting.

[0093] This step, by distinguishing between linear and nonlinear response modes under varying pressure differentials, enables the constraint function to possess dynamic response characteristics, achieving the following technical effects: First, the limiting function maintains a linear response when the differential pressure is in a stable state of change, so that the voltage reference value can be updated at a constant ratio. This ensures that the control gain and output continuity are maintained when the bus voltage and the vehicle-side demand voltage change smoothly, avoiding excessive constraint or response lag in the system during normal charging, thereby ensuring the smoothness and accuracy of the power regulation process. Second, when the differential pressure is changing rapidly, the limiting function automatically switches to a nonlinear response mode, so that the update amplitude of the voltage reference value decreases nonlinearly with the increase of the differential pressure change rate. This effectively suppresses the overshoot of the bus voltage during the differential pressure surge phase, improves the damping characteristics of the control loop, prevents transient current surges caused by voltage changes, and enhances the system's ability to quickly suppress short-term disturbances. Third, by switching between stable and abrupt changes in response, the control system can achieve a dynamic adjustment strategy that balances sensitivity and robustness in different operating ranges, ensuring that energy transfer efficiency during normal operation and shock protection performance during abnormal disturbances coexist, thereby improving the adaptability of DC charger output bus voltage control and the overall stability of the system.

[0094] Then, based on the output of the constraint function, the updated voltage reference value is calculated:

[0095] in, This represents the updated voltage reference value at the current moment. This represents the deviation between the vehicle-side demand voltage and the bus output voltage. The update formula dynamically adjusts the proportional coefficient. This allows the bus voltage reference value to exhibit adaptive nonlinear response characteristics, enabling it to quickly track the demand voltage in steady state and suppress voltage surges during disturbances.

[0096] When the system is in the stable differential pressure range, the limiting function maintains a linear update pattern, resulting in a smooth control output and sensitive response. However, when the differential pressure enters the rapidly changing range, the function automatically switches to a nonlinear decay form, giving the voltage adjustment process a flexible buffering characteristic and preventing overshoot and oscillation. This dual-mode switching mechanism ensures that the control system possesses dynamic characteristics that balance stability and sensitivity in different operating ranges.

[0097] Furthermore, to improve the coordination between voltage limiting control and output current, in this embodiment, a current feedback signal is introduced in the calculation of the limiting function, expressed as follows: When the output current is detected to be close to the rated upper limit or a transient fluctuation occurs, the limiting function output is synchronously corrected based on the current feedback signal. The formula for calculating the corrected limiting coefficient is:

[0098] in, Rated current, This is the current feedback correction factor. When the output current rises close to the rated value, the correction term reduces the overall gain, thereby reducing the voltage reference value update rate, ensuring consistency in the control behavior of voltage and current, and preventing current transient surges caused by individual voltage limiting.

[0099] This step establishes a constraint relationship between the limiting function and the current feedback control loop, achieving coordinated regulation of the voltage and current dual loops, and thus obtaining the following technical effects: First, the constraint function and the current feedback signal form a linkage constraint, so that the update of the voltage reference value no longer depends solely on the voltage change rate and voltage difference, but is synchronously corrected in combination with the current feedback. When the output current approaches the rated upper limit or transient fluctuations occur, the voltage adjustment amplitude is automatically reduced, thereby avoiding overshoot caused by single voltage control and realizing real-time coordination between voltage regulation and current load status. Second, when the current feedback control loop detects that the rate of change of current exceeds the set threshold, it can directly affect the output of the limiting function, so that the voltage control loop converges and updates the amount in advance during the high current surge stage, limits the rate of rise of bus voltage, prevents power devices from being subjected to excessive stress due to sudden current increase, and improves the electrical safety and dynamic robustness of the system. Third, by synchronously correcting the voltage reference value update amplitude, the voltage control and current control are transformed from parallel operation to a coupled and coordinated relationship. A unified dynamic constraint model is established, which ensures that the bus voltage and output current maintain a consistent trend when disturbances occur, improving the coordination and response consistency of the control loop. This enables bidirectional control of voltage and current in short-term impact scenarios, significantly improving the stability and energy transfer balance of the system.

[0100] Furthermore, in this embodiment, the voltage limiting constraint control and current feedback control are jointly constructed as a cooperative control link, enabling them to respond synchronously to voltage differential surge events. When a voltage differential surge is detected, the control unit simultaneously updates the voltage reference value. With current reference value This ensures that the two control loops remain consistent on the time axis, preventing short-term overshoot caused by energy distribution delays. This collaborative update process can be represented as:

[0101] in, This is the current actual output current. This is the filtered current signal. This is the current-side adjustment coefficient.

[0102] This step involves constructing a collaborative control link between voltage-limiting constraint control and current feedback control to achieve synchronous dynamic updates of voltage and current, resulting in the following technical effects: First, when the collaborative control link detects a sudden change in differential pressure, it simultaneously corrects the voltage reference value and the current reference value, so that the bus voltage adjustment and current regulation maintain time consistency, avoiding energy imbalance or instantaneous overshoot caused by single-loop delay, thereby achieving rapid linkage response during the stage of sudden increase in differential pressure, shortening the system stability recovery time, and improving the dynamic tracking accuracy under disturbance. Second, by establishing synchronous update logic between voltage limiting constraint control and current feedback control, the voltage control loop has the auxiliary constraint capability of the current side when the voltage difference changes suddenly, and the current control loop can also converge the output in advance according to the voltage change trend, forming a bidirectional driving collaborative feedback channel, thereby maintaining the stable operation of the system when voltage surge and current surge occur simultaneously, and improving the anti-disturbance and anti-surge performance. Third, the introduction of the collaborative control link means that the voltage and current control loops no longer operate independently, but form a unified control framework in the event of a sudden change in differential pressure. This enables joint adjustment and dynamic compensation of reference values, making the energy distribution process more continuous and coordinated, reducing phase deviation and control lag between voltage and current, and improving the overall efficiency of bus inrush current suppression and the real-time stability of the system.

[0103] Furthermore, during operation, the coordinated control link executes the control logic corresponding to the voltage control loop, current control loop, and contactor timing control loop respectively. Each control loop achieves coordinated updates by sharing control variables, that is, using differential pressure, rate of change, and current feedback as common inputs, so that the three can complete synchronous calculation and updates within the same control cycle.

[0104] This step achieves the following technical effects by executing the control logic of the voltage control loop, current control loop, and contactor timing control loop separately within the coordinated control link, and by using shared control variables to achieve coordinated updates: First, the collaborative control link establishes a unified variable interaction mechanism between the voltage loop, current loop, and contactor timing loop, so that the target quantities of each control loop are calculated synchronously within the same control cycle. By sharing differential pressure, current change rate, and timing state parameters, it ensures that the response direction of each control loop is consistent, avoids mutual cancellation or delay of control logic, and improves the time coordination and execution consistency of the overall control chain. Second, during the charging process, when the contactor operates or the communication timing changes, the contactor timing control loop can feed back the status quantity to the voltage loop and current loop in real time, so that the voltage limiting and current limiting commands can be dynamically adjusted according to the timing of the contactor closing or opening, preventing voltage surges or current surges caused by control delays or judgment deviations, and realizing cross-link timing adaptive control. Third, by coordinating updates through shared control variables, the collaborative control link forms a closed-loop regulation system under multi-loop interaction. The voltage, current, and contactor control units execute update commands based on the same data, reducing signal redundancy and control lag, and ensuring that the bus voltage and output current maintain a smooth transition during the contactor dynamic switching phase, thereby improving the system's response synchronization and operational stability.

[0105] For example, when the rate of change of differential pressure exceeds a preset threshold and the output current approaches the rated value, the limiting function automatically enters the nonlinear response mode and outputs updated coefficients. The voltage reference value is rapidly reduced, making the adjustment range of the voltage reference value lower than 30% to 50% under stable operating conditions. At this time, the current feedback correction term further weakens the gain, and the current reference value in the coordinated link decreases synchronously, realizing the joint suppression of voltage and current during the sudden change phase, thereby effectively eliminating the bus inrush current.

[0106] Thus, step S4 establishes a nonlinear limiting function based on voltage change rate, demand change rate, and voltage difference, and combines it with current feedback correction and collaborative link synchronous update mechanism to realize the adaptive, nonlinear, and collaborative characteristics of bus voltage limiting control. It can dynamically balance the voltage and current change rates under short-term disturbance conditions, significantly improving the inrush current suppression effect and the overall dynamic stability of the system.

[0107] In step S5, to achieve precise regulation of the bus voltage and immediate suppression of inrush current, the charger output voltage needs to be dynamically adjusted based on the updated voltage reference value from step S4. This step is an execution stage under voltage-limited constraint control. Its core purpose is to transform the reference voltage value, corrected by the limiting function and current feedback, into specific power conversion control commands, thereby achieving smooth regulation of the bus voltage at the physical level.

[0108] Specifically, the control unit acquires the updated voltage reference value. Then, the modulation parameters of the power converter are immediately corrected to ensure the bus output voltage. Towards Convergence. For example, the power converter may employ a full-bridge or bidirectional DC / DC topology, with control methods including a composite control of voltage loop regulation and current loop constraint. In this process, the voltage loop... Calculate the voltage deviation in real time, using the target value as an example:

[0109] The control unit generates a modulation signal based on the deviation value to adjust the duty cycle or phase shift angle of the PWM (Pulse Width Modulation) to correct the bus output voltage.

[0110] In some embodiments of this application, to avoid jumps in the control quantity due to sudden changes in the reference value, a smooth transition strategy can be introduced during voltage adjustment. Specifically, a proportional-integral (PI) control structure can be adopted, with anti-saturation protection set in the integral stage. When the output voltage rapidly approaches the reference value, the integral stage automatically weakens to prevent overshoot or reverse oscillation. The proportional loop then adjusts the output response amplitude in real time according to the transient change rate of the deviation, enabling the bus voltage to smoothly track the reference value in a short time.

[0111] After the voltage control signal is generated, it is output to the drive system. The drive system controls the switching on and off of the power devices to gradually correct the bus voltage. This process forms a closed-loop feedback system: the voltage sampling unit detects changes in the bus voltage in real time and feeds the detected value back to the control unit for deviation calculation and reference value update in the next cycle. Through this closed-loop regulation mechanism, the bus voltage is continuously corrected within the control cycle, ensuring that its output trajectory remains dynamically consistent with the target reference value.

[0112] Furthermore, to ensure a balance between control stability and response speed, an adaptive gain adjustment mechanism can be set. When the system is in the initial stage of voltage limiting constraints and the deviation is large, the controller gain remains at a high level to quickly reduce the voltage difference; as the bus voltage gradually approaches the reference value, the control gain automatically decreases, achieving a natural transition from response speed to stable accuracy, thereby avoiding secondary overshoot or oscillation of the output voltage.

[0113] In other embodiments of this application, the current feedback signal can continue to participate in the control quantity correction during the control execution phase. When the output current rise rate is detected to be too fast or close to the rated upper limit, the control unit introduces a suppression factor into the voltage regulation to limit the rise rate of the bus voltage, thereby keeping the voltage and current dynamically coordinated. This strategy effectively prevents current spikes during disturbance phases, further enhancing the suppression effect of inrush current.

[0114] For example, in actual operation, when the updated reference voltage rises by tens of volts, the voltage control unit can complete the duty cycle adjustment within milliseconds; simultaneously, the current loop feedback correction frequency is the same as the voltage loop, ensuring strict synchronization between bus voltage adjustment and current response in the time domain. Through this dynamic, smooth, and coupled adjustment method, the output voltage can quickly approach the target value under voltage-limiting constraints, while avoiding the response jumps and energy overshoot problems present in traditional voltage control, thereby achieving stable and controllable regulation of the bus voltage.

[0115] In step S6, the system enters the steady-state convergence phase. By continuously updating the voltage reference value and synchronously adjusting the output voltage, the bus voltage and the vehicle demand voltage are dynamically consistent. When the difference between the two gradually converges to the allowable range, the system automatically exits the voltage limit constraint state, returns to the normal operation mode, and continues to perform normal reference value updates and voltage regulation according to the vehicle side demand voltage.

[0116] Specifically, two core tasks are repeatedly performed in each control cycle: updating the voltage reference value based on the output voltage, demand voltage, and differential voltage status. According to the updated Adjust bus output voltage The above cycle operates at a high frequency, forming a real-time self-correcting closed loop that continuously converges the bus voltage to the vehicle's required voltage.

[0117] To avoid system oscillations and overshoots during the convergence process, a differential pressure convergence monitoring mechanism is introduced in this embodiment to continuously monitor the differential pressure. ,when continuously below the threshold And the rate of change When the voltage approaches zero, the system is deemed to have reached steady-state convergence. At this point, the voltage limiting constraint control logic automatically shuts down, exits the voltage limiting state, and returns to the normal voltage control mode.

[0118] After exiting the voltage limiting state, it enters the demand voltage tracking phase. Vehicle-side demand voltage. It continues to update dynamically and tracks its changing trend in real time, maintaining synchronization between the output voltage and the demand voltage through a conventional voltage control loop. Unlike the voltage-limiting state, the reference value update rate returns to normal levels, and the control response curve transitions from nonlinear constraint to linear dynamic, thereby improving energy transfer efficiency and reducing steady-state error.

[0119] During continuous operation, to prevent external disturbances from causing sudden voltage spikes or communication anomalies on the busbar, the differential voltage change rate, communication status, and current feedback are continuously monitored. When a new abrupt change trend is detected, the voltage limiting constraint control logic is automatically re-triggered, achieving an adaptive switch from normal operation to voltage limiting state, forming a complete self-recovering control closed loop. This dynamic switching mechanism ensures that the system maintains rapid response and high stability in the face of multiple disturbance events during long-term operation.

[0120] Meanwhile, throughout the entire voltage limiting control to convergence process, the internal collaborative control loop remains operational. The voltage control loop and current control loop continue to share key control variables, and the contactor timing control loop synchronously adjusts the action timing according to the voltage difference change, ensuring the coordination and consistency of voltage, current, and mechanical action. This multi-loop collaborative continuous operation structure enables the system to prevent secondary impacts caused by mechanical factors such as early contactor opening or delayed contactor closing while the voltage change stabilizes.

[0121] For example, after a sudden surge in bus voltage, convergence is typically completed within tens of milliseconds: the voltage difference gradually decreases to below the threshold, the voltage change rate approaches zero, and the current waveform returns to stability; thereafter, the voltage limiting control is automatically exited, and the system enters the normal voltage tracking phase. During this phase, the voltage reference value continues to be updated according to the changes in the vehicle's required voltage, ensuring that the entire charging process remains stable and seamless.

[0122] Thus, step S6 establishes a complete closed-loop process from the voltage limiting constraint stage to the steady-state tracking stage. This process can maintain the long-term consistency between the bus voltage and the demand voltage under multiple disturbances, communication interruptions, or load fluctuations, significantly improving the continuity and reliability of system operation and ensuring that the DC charger outputs stably throughout the entire charging cycle without inrush current.

[0123] In summary, this method achieves full-process suppression of inrush current by dynamically acquiring, calculating the rate of change of the DC bus output voltage of the charger and the demand voltage on the vehicle side, applying voltage limiting constraints and coordinated control. It can actively limit the rate of rise of the bus voltage under disturbances such as sudden rise in output voltage, communication abnormalities or load fluctuations, smoothly adjust the energy transfer process, keep the bus voltage dynamically consistent with the demand voltage of the vehicle, and prevent high-amplitude current surges from causing stress damage to power devices and contactors, thereby ensuring the safe, stable and efficient operation of the system throughout the charging process.

[0124] It should be noted that, although the embodiments in this application are based on... Figure 1 Steps S1 to S6 are described sequentially, but this does not mean that steps S1 to S6 must be performed in a strict order. The reason this embodiment follows this order is... Figure 1The order in which steps S1 to S6 are described is provided to facilitate understanding of the technical solutions of the embodiments of this application by those skilled in the art. In other words, in the embodiments of this application, the order of steps S1 to S6 can be appropriately adjusted according to actual needs.

[0125] Example 2: like Figure 2 As shown, this embodiment provides a DC charger output DC bus inrush current suppression system, comprising: Acquisition module 1 is used to acquire the output voltage of the charger's DC bus and the required voltage on the vehicle side and form a voltage sequence; Calculation module 2 is used to calculate the rate of change of output voltage, the rate of change of demand voltage, and the voltage difference between demand voltage and output voltage based on the voltage sequence. The determination module 3 is used to determine whether to enter the voltage limiting constraint control state based on the rate of change of output voltage, the rate of change of demand voltage, and the continuity of communication timing, combined with a preset threshold. Control module 4 is used to determine the limiting function and generate an updated voltage reference value based on the rate of change of output voltage, the rate of change of demand voltage, and the voltage difference under voltage limiting constraint control. The execution module 5 is used to adjust the output voltage of the power converter according to the updated voltage reference value, and when it detects that the output voltage is close to the demand voltage, the control system exits the voltage limit constraint control state and continues to update the voltage reference value and adjust the output voltage according to the demand voltage.

[0126] By adopting the above technical solution, through the hierarchical collaborative operation of the acquisition module 1, calculation module 2, judgment module 3, control module 4 and execution module 5, real-time monitoring of the voltage status of the charger output terminal and the vehicle side, dynamic judgment of voltage difference and execution of voltage limiting constraints can be realized. It can quickly enter the voltage limiting control state when the output voltage changes suddenly or the communication is abnormal, and dynamically correct the output voltage reference value of the power converter, thereby suppressing the sudden rise of the bus voltage and the current surge peak, and ensuring the system's operational stability and energy transfer continuity under short-term disturbances. Specifically, the acquisition module 1 provides voltage time-series data, which forms the basis for the calculation module 2 to calculate the voltage change rate and voltage difference. The calculation module 2 compares the voltage change rates at the output and demand ends in real time. The judgment module 3 identifies the sudden change trend of the bus voltage based on the change rate and communication continuity and triggers voltage limiting control. Under the voltage limiting state, the control module 4 determines the limiting function based on the voltage difference and change rate, and generates a constrained voltage reference value. The execution module 5 adjusts the output of the power converter according to the updated reference value to keep the bus voltage and the demand voltage dynamically consistent. After the deviation converges, it exits the voltage limiting constraint, realizing smooth voltage recovery and closed-loop steady-state control of the system.

[0127] In some embodiments of this application, the system may further include a learning threshold module, which is communicatively connected to the determination module 3, and is used to adaptively adjust a preset threshold based on historical data. The historical data includes at least one of voltage change trends, temperature characteristics, and communication delay characteristics during historical charging cycles.

[0128] This system achieves the following technical effects by introducing a learning-based threshold module to adaptively correct the judgment threshold: First, the learning-type threshold module establishes a multi-dimensional feature mapping relationship based on the voltage change trend, temperature characteristics and communication delay characteristics in the historical charging cycle, so that the judgment module 3 can automatically adjust the threshold judgment boundary under different ambient temperatures, different communication rates and different load conditions, thereby maintaining a dynamic balance between judgment sensitivity and reliability, and avoiding response lag or false triggering caused by fixed thresholds. Second, through continuous learning and weight iteration of historical data, the threshold module can extract statistical patterns in long-term operation and achieve periodic optimization of the threshold based on the characteristics of charging frequency and voltage fluctuation. This enables the system to maintain stable entry and exit judgment criteria in complex scenarios such as high temperature, high frequency oscillation or unstable communication, thereby improving the accuracy and robustness of voltage limit control triggering. Third, confidence assessment and outlier filtering mechanisms can be introduced during the adaptive adjustment process to ensure that the threshold correction results are not affected by random fluctuations and transient noise, maintain the continuity and predictability of threshold changes, thereby realizing the transformation of threshold setting from static fixed value to dynamic learning, and improving the system's environmental adaptability and intelligence under long-term operating conditions.

[0129] In some embodiments of this application, the system further includes a coordination module connected to the control module 4 and the execution module 5, for forming a nonlinear coordination control link, which includes: The constraint function unit is used to perform a linear response when the pressure difference changes steadily and a nonlinear response when the pressure difference changes rapidly. The current feedback unit is used to correct the update magnitude of the voltage reference value based on the current feedback signal. The synchronous update unit is used to simultaneously update the voltage reference value and the current reference value when a sudden change in differential pressure is detected.

[0130] This technical solution constructs a nonlinear collaborative control link by setting up a collaborative module, thereby achieving joint coordination between voltage control and current control and obtaining the following technical effects: First, the collaborative module restricts the function unit to execute a linear response when the differential pressure changes steadily and a nonlinear response when the differential pressure changes rapidly, so that the voltage regulation process has adaptive flexibility. It maintains linear control accuracy under stable operating conditions and enhances the suppression capability under sudden operating conditions. Thus, it automatically weakens the adjustment step size during the stage of sudden rise in bus voltage or current surge, ensuring the continuity and safety of voltage and current change process. Second, the current feedback unit introduces the real-time current signal into the voltage reference value correction logic, enabling the voltage control loop to dynamically adjust and update the amplitude according to the rate of current change, achieving coordinated adjustment of bidirectional constraints. When the current approaches the upper limit or transient fluctuations occur, the voltage adjustment amount is automatically converged to prevent voltage overshoot or power device impact, thereby improving the robustness and response consistency of the system under high dynamic loads. Third, when the synchronous update unit detects a sudden change in differential pressure, it simultaneously corrects the voltage and current reference values, forming a parallel response path. This enables the collaborative module to complete the dual-loop synchronous update within milliseconds, avoiding the energy imbalance and impact superposition effect caused by single-loop delay. This significantly improves the transient stability and overall control coordination of the DC charger under sudden disturbances.

[0131] In summary, this system, through the coordinated operation of modules such as acquisition module 1, calculation module 2, judgment module 3, control module 4, and execution module 5, and combined with the dynamic participation of the learning threshold module and the coordination module, achieves real-time monitoring of DC bus voltage and vehicle-side demand voltage, adaptive threshold correction, and nonlinear coordinated control of voltage and current. It can quickly enter the voltage limiting constraint state when there are sudden voltage changes at the output end, communication abnormalities, or abnormal contactor operation, and complete the synchronous update of voltage reference values ​​and current reference values. It effectively suppresses the peak value of bus inrush current and maintains the dynamic stability and safe and reliable operation of the system under short-term disturbances.

[0132] The above-disclosed embodiments are merely preferred embodiments of the present invention, but the present invention is not limited thereto. Any non-creative variations that can be conceived by those skilled in the art, as well as any improvements and modifications made without departing from the principles of the present invention, should fall within the protection scope of the present invention.

Claims

1. A method for suppressing inrush current on the DC bus output of a DC charger, characterized in that, Includes the following steps: The output voltage of the charger's DC bus and the demand voltage on the vehicle side are collected to form a voltage sequence; Based on the voltage sequence, calculate the rate of change of the output voltage, the rate of change of the demand voltage, and the voltage difference between the demand voltage and the output voltage. When the rate of change of the output voltage or the rate of change of the demand voltage exceeds a preset threshold, or when communication timing becomes discontinuous, the voltage limiting constraint control state is entered. Under the voltage-limiting constraint control state, a limiting function is determined based on the rate of change of the output voltage, the rate of change of the demand voltage, and the voltage difference, and the voltage reference value is updated accordingly. The output voltage is adjusted according to the updated voltage reference value; The voltage reference value is continuously updated and the output voltage is adjusted until the output voltage is consistent with the required voltage. Then, the voltage limiting constraint control state is exited, and the voltage reference value is updated and the output voltage is adjusted according to the required voltage.

2. The method for suppressing DC bus inrush current at the output of a DC charger as described in claim 1, characterized in that, The preset threshold is adaptively adjusted based on historical data through a learning-based trigger threshold model. The historical data includes at least one of voltage change trends, temperature characteristics, and communication delay characteristics within historical charging cycles.

3. The method for suppressing DC bus inrush current at the output of a DC charger as described in claim 1, characterized in that, The limiting function is a nonlinear differential pressure response function. The output value of the limiting function has a nonlinear relationship with the rate of change of the output voltage, the rate of change of the demand voltage, and the differential pressure. This nonlinear relationship imposes a constraint on the update amplitude of the voltage reference value during the change of the differential pressure.

4. The method for suppressing DC bus inrush current at the output of a DC charger as described in claim 3, characterized in that, The limiting function exhibits a linear response when the pressure difference is in a stable state of change, and a nonlinear response when the pressure difference is in a rapidly changing state.

5. A method for suppressing DC bus inrush current at the output of a DC charger as described in claim 3 or 4, characterized in that, The limiting function forms a constraint relationship with the output of the current feedback control loop, and the update magnitude of the voltage reference value is synchronously corrected according to the current feedback signal.

6. The method for suppressing DC bus inrush current at the output of a DC charger as described in claim 5, characterized in that, The voltage limiting constraint control and the current feedback control constitute a collaborative control link. When the collaborative control link detects a sudden change in the voltage difference, it synchronously updates the voltage reference value and the current reference value.

7. The method for suppressing DC bus inrush current at the output of a DC charger as described in claim 6, characterized in that, The coordinated control link executes the control logic corresponding to the voltage control loop, current control loop and contactor timing control loop respectively during the control process, and coordinates the updates by sharing control variables.

8. A DC charger output DC bus inrush current suppression system, characterized in that, include: The acquisition module is used to obtain the output voltage of the charger's DC bus and the required voltage on the vehicle side and form a voltage sequence; The calculation module is used to calculate the rate of change of the output voltage, the rate of change of the demand voltage, and the voltage difference between the demand voltage and the output voltage based on the voltage sequence. The determination module is used to determine whether to enter the voltage limiting constraint control state based on the rate of change of the output voltage, the rate of change of the demand voltage, and the continuity of the communication timing, in conjunction with a preset threshold. The control module is used to determine the limiting function and generate an updated voltage reference value based on the rate of change of the output voltage, the rate of change of the demand voltage, and the voltage difference under the voltage limiting constraint control state. The execution module is used to adjust the output voltage of the power converter according to the updated voltage reference value, and when it detects that the output voltage is close to the required voltage, the control system exits the voltage limiting constraint control state, and continues to update the voltage reference value and adjust the output voltage according to the required voltage.

9. The DC charger output DC bus inrush current suppression system as described in claim 8, characterized in that, It also includes a learning threshold module, which is communicatively connected to the determination module and is used to adaptively adjust the preset threshold based on historical data. The historical data includes at least one of voltage change trends, temperature characteristics, and communication delay characteristics during historical charging cycles.

10. The DC charger output DC bus inrush current suppression system as described in claim 8, characterized in that, It also includes a coordination module, which is connected to the control module and the execution module to form a nonlinear coordination control link, the nonlinear coordination control link including: A constraint function unit is configured to perform a linear response when the pressure difference changes steadily and a nonlinear response when the pressure difference changes rapidly; A current feedback unit is used to correct the update magnitude of the voltage reference value based on the current feedback signal; The synchronous update unit is used to simultaneously update the voltage reference value and the current reference value when a sudden change in the differential pressure is detected.

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