Charging pile output power limiting method and system based on battery dynamic parameters

Abstract

The invention discloses a charging pile output power limiting method and system based on battery dynamic parameters. The method comprises the steps that the maximum output power Pmax of a charging pile is set based on the power supply capacity Pgrid of a power grid, and a first sampling period T1 is set; acquiring a battery open-circuit voltage Uoc, an initial charging voltage U0 and a charging current I0; obtaining Rbat based on the Uoc, the U0 and the I0; based on the Pmax, the Rbat and the Uoc, the maximum allowable current Imax of the charging pile is determined; a charging request current Ireq is obtained, if Ireq is larger than Imax, I is set to be equal to Imax, and otherwise I is set to be equal to Ireq; and based on T1, collecting a charging voltage U and a charging current I, and updating Uoc and Rbat so as to limit the output power of the charging pile. The method has the advantages that the maximum allowable output current is dynamically adjusted according to the dynamic parameters of the battery, the output power is effectively prevented from exceeding the limit, and the polarization of the battery is prevented from being aggravated.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle charging, and particularly to a charging pile output power limiting algorithm and system based on battery dynamic parameters. Background Art

[0002] In the charging technology system of electric vehicles, the charging pile, as a key hub for energy transmission, undertakes the important mission of efficiently and safely injecting grid electric energy into the vehicle power battery. During the charging process, the charging pile needs to dynamically and accurately adjust the output power according to the real-time requirements of the electric vehicle power battery, so as to achieve the goal of efficient energy transmission. This is not only the key to improving the charging efficiency, but also an important link to ensure charging safety and extend the battery service life.

[0003] However, the adjustment of the charging pile output power is not unrestricted, but is subject to two key constraints. First, the charging pile itself has a rated power limit, which is determined by the hardware design, heat dissipation capacity, and electrical characteristics of the charging pile. Once the output power exceeds this rated upper limit, the charging pile may be damaged due to overheating, overload of electrical components, etc., and even cause safety accidents. Second, the output power of the charging pile also needs to adapt to the power supply capacity P grid of the power grid. The power supply capacity of the power grid is limited. If the output power of the charging pile is too large, it may cause local power grid voltage drop and frequency fluctuation, affect the stable operation of the power grid, and even trigger the protection device of the power grid, resulting in large-scale power outages.

[0004] Most traditional power control schemes adopt a fixed current limit strategy. Its core logic is based on a preset static parameter model, that is, according to the rated power of the charging pile, the power supply capacity of the power grid, and some basic parameters of the battery, a fixed charging current value is preset in advance. During the charging process, the charging pile delivers electric energy to the battery according to this fixed current value. This strategy is simple and easy to implement, but it exposes many drawbacks in practical applications.

[0005] As the power battery is used, its state of charge (SOC), temperature, and aging degree will continuously change. These factors will cause the battery parameters equivalent internal resistance (R bat ) and open circuit voltage (U oc ) to exhibit significant dynamic characteristics. This dynamic change makes it difficult for the traditional fixed current mode to adapt to the actual needs of the battery, thus causing two typical problems.

[0006] (1) When the battery voltage rises, since the charging current is fixed, according to the power calculation formula P = UI (where P is power, U is voltage, and I is current), the output power will increase accordingly. Once the output power exceeds the rated upper limit of the charging pile, the protection mechanism of the charging pile will be triggered, and the charging process will be forced to interrupt. This will not only affect the user's charging experience but also may cause damage to the charging pile and the battery.

[0007] (2) When the internal resistance of the battery suddenly increases, since the charging current cannot be adjusted in time, according to Ohm's law U = IR (where U is the voltage drop, I is the current, and R is the resistance), the voltage drop inside the battery will increase, resulting in a decrease in the actual charging voltage of the battery. To maintain a certain charging power, the charging pile needs to increase the output voltage, but this will further increase the power loss. At the same time, the excessive current will also accelerate the polarization phenomenon of the battery, reducing the performance and lifespan of the battery. Summary of the Invention

[0008] The technical problem to be solved by the present invention is: to provide an output power limiting method and system that can dynamically adjust the maximum allowable output current of the charging pile in real time according to the dynamic parameters of the battery, ensuring that the charging pile can always achieve the maximum output power under the premise of safety throughout the charging process of the battery, effectively avoiding the problem of triggering the protection mechanism to interrupt charging due to the output power exceeding the rated upper limit of the charging pile caused by the increase in battery voltage, and at the same time avoiding the problems of increased power loss rate and aggravated battery polarization phenomenon caused by the increase in the internal voltage drop of the battery and the inability of the system to adjust the current in time.

[0009] To solve the above technical problem, the technical solution provided by the present invention, an output power limiting method based on battery dynamic parameters, at least includes the following steps:

[0010] Step S1, based on the power supply capacity P of the power grid grid Set the maximum output power P of the charging pile max , and set the first sampling period T1;

[0011] Step S2, obtain the open-circuit voltage U of the battery oc , as well as the initial charging voltage U0 and charging current I0 of the charging pile;

[0012] Step S3, based on the open-circuit voltage U of the battery oc , as well as the initial charging voltage U0 and charging current I0 of the charging pile, obtain the initial battery equivalent resistance R bat ;

[0013] Step S4, based on the maximum output power P of the charging pile max , the battery equivalent resistance R bat and the open-circuit voltage U of the battery oc , determine the maximum allowable current I of the charging pilemax , which is specifically implemented by the following calculation method:

[0014]

[0015] Step S5: Obtain the vehicle charging request current I req , if the vehicle charging request current I req is greater than the maximum allowable current I of the charging pile max , then set the charging current I of the current charging pile to I max , otherwise set the charging current I of the current charging pile to I req ;

[0016] Step S6: Based on the first sampling period T1, collect the charging voltage U and charging current I of the charging pile in real time, and update the battery open-circuit voltage U oc and the battery equivalent resistance R bat ;

[0017] Step S7: Based on the updated battery open-circuit voltage U oc and the battery equivalent resistance R bat , repeat steps S4 - S5 to limit the output power of the charging pile.

[0018] A preferred embodiment, step S6 specifically includes the following steps:

[0019] Step S601: Based on the first sampling period T1, collect the charging voltage U k and charging current I k of the charging pile in the kth period in real time, where k > 1;

[0020] Step S602: Based on the charging voltage U k and charging current I k of the charging pile in the kth period, and the battery equivalent resistance Rbat k-1 in the (k - 1)th period, obtain the battery open-circuit voltage U oc k in the kth period, which is specifically implemented by the following calculation method:

[0021]

[0022] Step S603: Collect the charging voltage U k+1 and charging current I k+1 of the charging pile in the (k + 1)th period in real time, and based on the battery open-circuit voltage U oc k in the kth period, obtain the battery equivalent resistance R bat k+1, which is specifically implemented by the following calculation method:

[0023]

[0024] Step S604, update the current open-circuit voltage U of the battery oc to U oc k , and the equivalent resistance R of the battery bat is R bat k+1 .

[0025] In a preferred embodiment, in step S601, the charging voltage U k and charging current I k of the charging pile in the k-th cycle are collected in real time, or / and in step S603, the charging voltage U k+1 and charging current I k+1 of the charging pile in the (k + 1)-th cycle are collected in real time. A sliding average filter is used to suppress high-frequency noise, and the specific method is as follows:

[0026] Set the size of the sliding window to N, where N > 1;

[0027] Based on the first sampling period T1, N data points in this period are collected, and any one of the data points includes the charging voltage of the charging pile and the corresponding charging current;

[0028] Calculate the arithmetic mean of the N data points in this period, and use them as the charging voltage and charging current of the charging pile in this period after filtering. The specific calculation method is as follows:

[0029]

[0030] where U[i] is the charging voltage of the charging pile at the i-th data point in this period, and I[i] is the charging current of the charging pile at the i-th data point in this period.

[0031] In a preferred embodiment, when using the sliding average filter to suppress high-frequency noise, the following method is also used:

[0032] Set the first threshold η1;

[0033] Solve the standard deviation σ1 of the charging voltage of the charging pile among the N data points, and the standard deviation σ2 of the corresponding charging current. The specific calculation method is as follows:

[0034]

[0035] If σ1 ≥ η1 or σ2 ≥ η1, then increase the size of the sliding window N to enhance the sliding average filtering effect.

[0036] A preferred embodiment, the power supply capacity P of the power grid grid Set the maximum output power P of the charging pile max , which specifically includes the following steps:

[0037] Obtain the current power supply capacity P of the power grid through the smart meter grid ;

[0038] Set the second sampling period T2 and the second threshold η2;

[0039] Based on the second threshold η2 and the current power supply capacity P of the power grid grid Set the real-time maximum output power P of the charging pile max , which is specifically implemented by the following calculation method:

[0040] P max = η2 × P grid ;

[0041] Update the current power supply capacity P of the power grid based on the second sampling period T2 grid , thereby updating the maximum output power P of the charging pile max .

[0042] A preferred embodiment, the range of the second sampling period T2 is 10 - 30 s.

[0043] A preferred embodiment, the step S3 specifically includes the following steps:

[0044] Step S301, judge the current battery charging state based on the charging current I0;

[0045] Step S302, if the battery charging state is normal, then based on the open-circuit voltage U of the battery oc , and the initial charging voltage U0 and charging current I0 of the charging pile, obtain the initial equivalent resistance R of the battery bat , which is specifically implemented by the following calculation method:

[0046]

[0047] A preferred embodiment, the step S301 specifically includes the following steps:

[0048] If the detected value of the charging current I0 is 0, it is determined that the current battery charging state is abnormal, and the warning information sending mechanism is immediately triggered, otherwise it is determined that the current battery charging state is normal.

[0049] A preferred embodiment, the range of the first sampling period T1 is 1 - 5 s.

[0050] The present invention also provides a system using any one of the above-mentioned methods for limiting the output power of a charging pile based on battery dynamic parameters, which at least includes:

[0051] A grid monitoring module, configured to obtain the power supply capacity P of the grid in real time grid and set the maximum output power P of the charging pile based on the power supply capacity P of the grid grid ; max

[0052] A data acquisition module, which at least includes a voltage sensor and a current sensor, and is configured to collect the open-circuit voltage U of the battery oc , the initial charging voltage U0 and charging current I0 of the charging pile, as well as the real-time charging voltage U and charging current I, and transmit the collected data to the data processing module;

[0053] A data processing module, configured to calculate the equivalent resistance R of the battery based on the open-circuit voltage U of the battery oc , the initial charging voltage U0 and charging current I0 of the charging pile, and calculate the maximum allowable current I of the charging pile based on the maximum output power P bat , the equivalent resistance R of the battery max , and the open-circuit voltage U of the battery bat ; oc max

[0054] A vehicle communication module, configured to receive the charging current I requested by the vehicle req and transmit it to the control module;

[0055] A control module, based on the charging current I requested by the vehicle req and the maximum allowable current I of the charging pile max , outputs a control signal according to the following logic:

[0056] If the I req is greater than the I max , then set the current charging current I of the charging pile to I max , otherwise set the current charging current I of the charging pile to I req ;

[0057] A battery dynamic parameter update module, configured to periodically collect the real-time charging voltage U and charging current I based on the first sampling period T1, and update the open-circuit voltage U of the battery oc and the equivalent resistance R of the battery based on the real-time charging voltage U and charging current I bat , and transmit the updated open-circuit voltage U of the battery oc and the equivalent resistance R of the battery bat to the data processing module;

[0058] A power output module, configured to dynamically adjust the charging current I of the charging pile based on the control signal of the control module.

[0059] The method for limiting the output power of the charging pile based on the dynamic parameters of the battery according to the present invention has the following beneficial effects compared with the prior art:

[0060] (1) A method for limiting the output power of the charging pile based on the dynamic parameters of the battery disclosed by the present invention at least includes step S1 of setting the maximum output power P of the charging pile based on the power supply capacity P of the power grid grid and setting the first sampling period T1. On the one hand, by dynamically setting the maximum output power P of the charging pile max , it adapts to the real-time power supply capacity of the power grid, prevents the grid voltage from dropping or the frequency from fluctuating due to excessive charging power, and ensures the stability of the power grid; on the other hand, according to the change of the grid load, it flexibly adjusts the maximum output power P of the charging pile max , and improves the coordination between the charging pile and the power grid. max

[0061] Step S2, obtaining the open-circuit voltage U of the battery oc , as well as the initial charging voltage U0 and charging current I0 of the charging pile; step S3, based on the open-circuit voltage U of the battery oc , as well as the initial charging voltage U0 and charging current I0 of the charging pile, obtaining the initial battery equivalent resistance R bat . Wherein U oc reflects the current state of charge (SOC) and aging degree of the battery, U0 and I0 provide a reference value for the subsequent calculation of the battery internal resistance, and the three together constitute the starting point for the analysis of the dynamic characteristics of the battery. The acquisition of the initial parameters provides a data basis for the subsequent calculation of I max , ensuring that the power can be dynamically allocated according to the battery state at the initial stage of charging.

[0062] Step S4, based on the maximum output power P of the charging pile max , the battery equivalent resistance R bat and the open-circuit voltage U of the battery oc , determining the maximum allowable current I of the charging pile max , and restricting the charging current in real time to solve the problem of power overlimit caused by the rise of the battery voltage. Even if the battery voltage U oc increases due to the increase of SOC, I max can still be adaptively reduced, avoiding the power from breaking through the rated upper limit of the charging pile and preventing charging interruption and equipment damage. P max limits the power upper limit, and I max limits the current upper limit. The combination of the two can avoid potential safety hazards caused by the failure of a single constraint.

[0063] Step S5, obtaining the vehicle charging request current I req, if the vehicle charging request current I req is greater than the maximum allowable current I max of the charging pile, then set the charging current I of the current charging pile to I max , otherwise set the charging current I of the current charging pile to I req . Ensure that the maximum output power can always be achieved on the premise of safety, effectively avoiding the problem of triggering the protection mechanism to interrupt charging due to the output power exceeding the rated upper limit of the charging pile caused by the rise of the battery voltage, and avoiding the problem of increasing the power loss rate due to the inability to adjust the current in time, taking into account both charging efficiency and equipment safety.

[0064] Step S6, based on the first sampling period T1, collect the charging voltage U and charging current I of the charging pile in real time, and update the open-circuit voltage U oc of the battery and the equivalent resistance R bat of the battery based on the charging voltage U and charging current I of the charging pile. On the one hand, update U oc and R bat periodically, enabling the system to perceive the changes in the battery SOC, temperature, and aging state in real time, providing the latest data for the subsequent calculation of I max , and avoiding control lag caused by fixed parameters; on the other hand, reduce the polarization effect caused by the sudden increase in internal resistance by dynamically adjusting the current to match the change in R bat , reduce the attenuation of the battery capacity, and extend the service life.

[0065] Step S7, based on the updated open-circuit voltage U oc of the battery and the equivalent resistance R bat of the battery, repeat steps S4 - S5 to limit the output power of the charging pile. On the one hand, ensure that the power at any stage during the charging process is ≤ P max through continuous iterative parameter update and current adjustment, solving the problem of power overlimit caused by static parameters in the traditional scheme; on the other hand, even in the face of drastic fluctuations in battery parameters, the system can still quickly converge to the safe operating point through closed-loop control, avoiding charging interruption or equipment failure.

[0066] (2) For a method for limiting the output power of a charging pile based on dynamic battery parameters according to the present invention, step S6 specifically includes step S601, based on the first sampling period T1, collect the charging voltage U k and charging current I k of the charging pile in the k-th period in real time; step S602, based on the charging voltage U k and charging current I k of the charging pile in the k-th period, and the equivalent resistance R bat k-1 of the battery in the (k - 1)-th period, obtain the open-circuit voltage U oc kBy the real-time charging voltage (U k ) in the k-th cycle, current (I k ) and the equivalent battery resistance (R bat k-1 ) in the (k - 1)-th cycle, the current open-circuit voltage is deduced. On the one hand, the influence of transient interference is eliminated. By using historical resistance data (R bat k-1 ), the transient voltage drop is corrected to make U oc closer to the true electrochemical state of the battery; on the other hand, dynamic R bat compensation can avoid the lag in U oc calculation and ensure that the power limit strategy responds in a timely manner.

[0067] Step S603: Real-time collect the charging voltage U k+1 and charging current I k+1 within the (k + 1)-th cycle, and based on the open-circuit voltage U oc k of the battery in the k-th cycle, obtain the equivalent battery resistance R bat k+1 in the (k + 1)-th cycle; Step S604: Update the current open-circuit voltage U oc to U oc k , and the equivalent battery resistance R bat to R bat k+1 . The internal resistance of the battery varies significantly with SOC, temperature, and aging degree. By updating R bat through multi-cycle iteration, on the one hand, the power distribution deviation caused by fixed parameters is avoided, and on the other hand, the parameter calculation error is gradually corrected through multi-cycle iteration to avoid control oscillation caused by single-cycle noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 FIG. 47 is a flowchart of the technical solution of Embodiment 1 of a method for limiting the output power of a charging pile based on dynamic battery parameters according to the present invention;

[0069] Figure 2 FIG. 51 is a structural diagram of System Embodiment 2 of the method for limiting the output power of a charging pile using the method based on dynamic battery parameters according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0070] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0071] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0072] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, an integral connection, or a detachable connection; it may be the communication inside two elements; it may be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] Embodiment 1

[0074] A method for limiting the output power of a charging pile based on battery dynamic parameters in this embodiment is as Figure 1 shown, and at least includes the following steps:

[0075] Step S1, based on the power supply capacity P of the power grid grid set the maximum output power P of the charging pile max , and set the first sampling period T1. On the one hand, by dynamically setting the maximum output power P of the charging pile max to adapt to the real-time power supply capacity of the power grid, prevent the charging power from being too large and causing voltage drop or frequency fluctuation of the power grid, and ensure the stability of the power grid; on the other hand, according to the change of the power grid load, flexibly adjust the maximum output power P of the charging pile max , and improve the coordination between the charging pile and the power grid.

[0076] Based on the power supply capacity P of the power grid grid set the maximum output power P of the charging pile max , which specifically includes the following steps:

[0077] Obtain the current available power supply capacity P of the power grid through an intelligent electricity meter grid ;

[0078] Set the second sampling period T2 and the second threshold η2;

[0079] Based on the second threshold η2 and the current available power supply capacity P of the power grid grid set the real-time maximum output power P of the charging pile max , which is specifically implemented by the following calculation method:

[0080] p max = η2 × P grid ;

[0081] Update the current power supply capacity P of the power grid based on the second sampling period T2 grid , so as to update the maximum output power P of the charging pile max .

[0082] Among them, the range of the second sampling period T2 is 10 - 30 s. In this embodiment, the second period T2 is set to 10 s. The range of the first sampling period T1 is 1 - 5 s, and in this embodiment, the first sampling period T1 is set to 1 s.

[0083] Step S2, obtain the open-circuit voltage U of the battery oc , as well as the initial charging voltage U0 and charging current I0 of the charging pile. In this embodiment, the open-circuit voltage of the battery is read by the ADC digital-to-analog converter during the pre-charging stage.

[0084] Step S3, based on the open-circuit voltage U of the battery oc , as well as the initial charging voltage U0 and charging current I0 of the charging pile, obtain the initial battery equivalent resistance R bat , where U oc reflects the current state of charge (SOC) and aging degree of the battery, U0 and I0 provide a reference value for the subsequent calculation of the battery internal resistance, and the three together constitute the starting point for the analysis of the battery dynamic characteristics. The acquisition of the initial parameters provides a data basis for the subsequent I max calculation, ensuring that the power can be dynamically allocated according to the battery state at the charging start stage.

[0085] Step S3 specifically includes the following steps:

[0086] Step S301, judge the current charging state of the battery based on the charging current I0:

[0087] Step S302, if the battery charging state is normal, then based on the open-circuit voltage U of the battery oc , as well as the initial charging voltage U0 and charging current I0 of the charging pile, obtain the initial battery equivalent resistance R bat , which is specifically implemented by the following calculation method:

[0088]

[0089] Among them, step S301 specifically includes the following steps:

[0090] If the detected value of the charging current I0 is 0, it is determined that the current charging state of the battery is in an abnormal condition, and the sending mechanism of the warning information is immediately triggered, otherwise it is determined that the current charging state of the battery is in a normal state.

[0091] Step S4, based on the maximum output power P of the charging pile max 、battery equivalent resistance Rbat and the open-circuit voltage U of the battery oc , determine the maximum allowable current I of the charging pile max , which is specifically implemented by the following calculation method:

[0092]

[0093] Real-time constraint on the charging current to solve the problem of power overlimit caused by the rise of the battery voltage. Even if the battery voltage U oc increases due to the increase of SOC, I max can still adaptively decrease, avoiding the power breaking through the rated upper limit of the charging pile and preventing charging interruption and equipment damage. P max Limit the power upper limit, and I max limit the current upper limit. The combination of the two can avoid potential safety hazards caused by the failure of a single constraint.

[0094] Step S5, obtain the vehicle charging request current I req , if the vehicle charging request current I req is greater than the maximum allowable current I of the charging pile max , then set the current charging current I of the charging pile = I max , otherwise set the current charging current I of the charging pile = I req . Ensure that the maximum output power can always be achieved under the premise of safety, effectively avoiding the problem of triggering the protection mechanism to interrupt charging due to the output power exceeding the rated upper limit of the charging pile caused by the rise of the battery voltage, and taking into account both charging efficiency and equipment safety.

[0095] Step S6, based on the first sampling period T1, collect the charging voltage U and charging current I of the charging pile in real time, and update the open-circuit voltage U of the battery oc and the equivalent resistance R of the battery bat . On the one hand, update U oc and R bat periodically, so that the system can perceive the changes in the battery SOC, temperature and aging state in real time, provide the latest data for the subsequent I max calculation, and avoid control lag caused by fixed parameters; on the other hand, reduce the polarization effect caused by the sudden increase of the internal resistance by dynamically adjusting the current to match the R bat change, reduce the battery capacity attenuation, and extend the service life.

[0096] Step S6 specifically includes the following steps:

[0097] Step S601, based on the first sampling period T1, collect the charging voltage U of the charging pile in the kth period in real time k and the charging current I k , where k > 1.

[0098] Step S602: Based on the charging voltage U of the charging pile within the k-th cycle k and the charging current I k , as well as the battery equivalent resistance R of the (k - 1)-th cycle bat k-1 , obtain the open-circuit voltage U of the battery in the k-th cycle oc k . The specific implementation is as follows:

[0099]

[0100] By using the real-time charging voltage (U k ) and current (I k ) in the k-th cycle and the battery equivalent resistance (R bat k-1 ) in the (k - 1)-th cycle to reverse-infer the current open-circuit voltage. On the one hand, eliminate the influence of transient interference, and correct the transient voltage drop through historical resistance data (R bat k-1 ) to make U oc closer to the true electrochemical state of the battery; on the other hand, dynamic R bat compensation can avoid the lag in U oc calculation and ensure that the power limit strategy responds in a timely manner.

[0101] Step S603: Real-time collect the charging voltage U of the charging pile within the (k + 1)-th cycle k+1 and the charging current I k+1 , and based on the open-circuit voltage U of the battery in the k-th cycle oc k , obtain the battery equivalent resistance R of the (k + 1)-th cycle bat k+1 . The specific implementation is as follows:

[0102]

[0103] Step S604: Update the current open-circuit voltage U oc to U oc k , and the battery equivalent resistance R bat to R bat k+1 .

[0104] The internal resistance of the battery varies significantly with SOC, temperature, and aging degree. By updating R bat through multi-cycle iteration, on the one hand, avoid the power distribution deviation caused by fixed parameters, and on the other hand, gradually correct the parameter calculation error using multi-cycle iteration to avoid control oscillation caused by single-cycle noise.

[0105] Among them, in step S601, the real-time collection of the charging voltage U of the charging pile within the k-th cyclek and charging current I k or / and the charging voltage U of the charging pile collected in real time in the (k + 1)-th cycle in step S603 k+1 and charging current I k+1 , and a moving average filter is adopted to suppress high-frequency noise. The specific method is as follows:

[0106] Set the moving window size to N, where N is greater than 1;

[0107] Based on the first sampling period T1, N data points in this period are collected. Any data point includes the charging voltage of the charging pile and the corresponding charging current;

[0108] Calculate the arithmetic mean of the N data points in this period, and use them as the charging voltage of the charging pile and the charging current in this period after filtering respectively. The specific calculation method is as follows:

[0109]

[0110] where U[i] is the charging voltage of the charging pile at the i-th data point in this period, and I[i] is the charging current of the charging pile at the i-th data point in this period;

[0111] Set the first threshold η1;

[0112] Solve the standard deviation σ1 of the charging voltage of the charging pile among the N data points, and the standard deviation σ2 of the corresponding charging current. The specific calculation method is as follows:

[0113]

[0114] If σ1 ≥ η1 or σ2 ≥ η1, increase the moving window size N to enhance the moving average filtering effect.

[0115] On the one hand, by calculating the arithmetic mean of the N data points in the window, electromagnetic interference, switching noise and other high-frequency noises are effectively filtered, so that the measured values of the charging voltage U of the charging pile and the corresponding charging current I in this period are closer to the true values, random fluctuations are eliminated, data stability is improved, and measurement errors of battery parameters R bat and U oc are avoided; on the other hand, by calculating the standard deviations σ1 and σ2 of the charging voltage and current in real time, the moving window size N is dynamically adjusted to realize the adaptive adjustment of the noise suppression intensity.

[0116] Step S7, based on the updated open-circuit voltage U of the battery oc and the equivalent resistance R of the battery bat, repeat steps S4 - S5 to limit the output power of the charging pile. On the one hand, through continuous iterative parameter update and current regulation, ensure that the power at any stage during charging is ≤ P max , solve the problem of power over - limit caused by static parameters in the traditional solution; on the other hand, even in the face of drastic fluctuations in battery parameters, the system can still quickly converge to a safe operating point through closed - loop control, avoiding charging interruption or equipment failure.

[0117] Embodiment 2

[0118] This embodiment also provides a system applying the method for limiting the output power of a charging pile based on dynamic battery parameters as described in any one of the above, as Figure 2 shown, at least including:

[0119] Grid monitoring module, used to obtain the power supply capacity P of the grid in real - time grid , and set the maximum output power P of the charging pile based on the power supply capacity P of the grid grid ; max ;

[0120] Data acquisition module, at least including a voltage sensor and a current sensor, used to collect the open - circuit voltage U of the battery oc , the initial charging voltage U0 and charging current I0 of the charging pile, as well as the real - time charging voltage U and charging current I, and transmit the collected data to the data processing module;

[0121] Data processing module, used to calculate the equivalent resistance R of the battery based on the open - circuit voltage U of the battery oc , the initial charging voltage U0 and charging current I0 of the charging pile, and calculate the maximum allowable current I of the charging pile based on the maximum output power P bat , the equivalent resistance R of the battery max , and the open - circuit voltage U of the battery bat ; oc ; max ;

[0122] Vehicle communication module, used to receive the charging current I requested by the vehicle req , and transmit it to the control module;

[0123] Control module, based on the charging current I requested by the vehicle req and the maximum allowable current I of the charging pile max , output a control signal according to the following logic:

[0124] If the I req is greater than the I max , then set the current charging current I of the charging pile to I max , otherwise set the current charging current I of the charging pile to I req ;

[0125] A battery dynamic parameter update module, which is configured to periodically collect the real-time charging voltage U and the charging current I based on the first sampling period T1, and update the battery open-circuit voltage U based on the real-time charging voltage U and the charging current I oc and the battery equivalent resistance R bat , and transmit the updated battery open-circuit voltage U oc and the battery equivalent resistance R bat to the data processing module;

[0126] A power output module, which is configured to dynamically adjust the charging current I of the charging pile based on the control signal of the control module.

[0127] In summary, the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for limiting the output power of a charging pile based on battery dynamic parameters, characterized in that, At least include the following steps: Step S1, based on the power supply capacity P of the power grid grid Set the maximum output power P of the charging pile max , and set the first sampling period T l ; Step S2, obtain the open-circuit voltage U of the battery oc , as well as the initial charging voltage U0 and charging current I0 of the charging pile; Step S3, based on the battery open-circuit voltage U oc , and the initial charging voltage U0 and charging current I0 of the charging pile, obtain the initial battery equivalent resistance R bat ; Step S4, based on the maximum output power P of the charging pile max , the equivalent resistance R of the battery bat , and the open-circuit voltage U of the battery oc , determine the maximum allowable current I of the charging pile max , which is specifically implemented by the following calculation method: Step S5, obtain the vehicle charging request current I req , if the vehicle charging request current I req is greater than the maximum allowable current I of the charging pile max , then set the charging current I of the current charging pile to I max , otherwise set the charging current I of the current charging pile to I req ; Step S6, based on the first sampling period T1, collect the charging voltage U and charging current I of the charging pile in real time, and update the battery open-circuit voltage U and the battery equivalent resistance R based on the charging voltage U and charging current I of the charging pile oc and the battery equivalent resistance R bat ; Step S7, based on the updated open-circuit voltage U of the battery oc and the equivalent resistance R of the battery bat , repeat steps S4 - S5 to limit the output power of the charging pile.

2. A method for limiting the output power of a charging pile based on battery dynamic parameters according to claim 1, characterized in that The step S6 specifically includes the following steps: Step S601, based on the first sampling period T1, in real time collect the charging voltage U of the k-th period k and the charging current I k , where k > l; Step S602: Based on the charging voltage U of the charging pile and the charging current I within the k-th cycle, as well as the equivalent battery resistance R in the (k - 1)-th cycle k and the charging current I k , the open-circuit voltage U of the battery in the k-th cycle is obtained bat k-1 , which is specifically implemented by the following calculation method: oc k ​ Step S603, in real time, collect the charging voltage U of the charging pile in the (k + 1)-th cycle k+1 and the charging current I k+1 , and based on the open-circuit voltage U of the battery in the k-th cycle oc k , obtain the equivalent resistance R of the battery in the (k + 1)-th cycle bat k+1 , which is specifically implemented by the following calculation method: Step S604, update the current open-circuit voltage U of the battery oc to U oc k , and the equivalent resistance R of the battery bat is R bat k+1 .

3. A method for limiting the output power of a charging pile based on battery dynamic parameters according to claim 2, characterized in that, In the step S601, the charging voltage U of the charging pile within the k-th cycle is collected in real time k and the charging current I k or / and in the step S603, the charging voltage U of the charging pile within the (k + 1)-th cycle is collected in real time k+1 and the charging current I k+1 , and a moving average filter is used to suppress high-frequency noise. The specific method is as follows: Set the sliding window size to N, where N > 1; Based on the first sampling period T1, collect N data points within this period. Any one of the data points includes the charging voltage of the charging pile and the corresponding charging current; Calculate the arithmetic mean of the N data points within this period, and use them as the charging voltage and the charging current of the charging pile after filtering in this period respectively. The specific calculation method is as follows: Where U[i] is the charging voltage of the charging pile at the i-th data point within this period, and I[i] is the charging current of the charging pile at the i-th data point within this period.

4. A method for limiting the output power of a charging pile based on battery dynamic parameters according to claim 3, characterized in that, For suppressing high-frequency noise by using moving average filtering, the following method is also adopted: Set the first threshold η1; Solve the standard deviation σ1 of the charging voltage of the charging pile and the standard deviation σ2 of the corresponding charging current among the N data points. The specific calculation method is as follows: If σ1 ≥ η1 or σ2 ≥ η1, increase the sliding window size N to enhance the moving average filtering effect.

5. A method for limiting the output power of a charging pile based on battery dynamic parameters according to any one of claims 1-4, characterized in that: The power supply capacity P based on the power grid grid Set the maximum output power P of the charging pile max , which specifically includes the following steps: Obtain the current available power supply capacity P of the power grid through the smart meter grid ; Set the second sampling period T2 and the second threshold η2; Based on the second threshold η2 and the current power supply capacity P of the current power grid grid Set the maximum output power P of the real-time charging pile max , which is specifically implemented by the following calculation method: p max = η2 × P grid ; Update the current power supply capacity P of the power grid based on the second sampling period T2 grid , so as to update the maximum output power P of the charging pile max .

6. A method for limiting the output power of a charging pile based on battery dynamic parameters according to claim 5, characterized in that: The range of the second sampling period T2 is 10 - 30s.

7. A method for limiting the output power of a charging pile based on battery dynamic parameters according to any one of claims 1-4 or 6, characterized in that, The step S3 specifically includes the following steps: Step S301, judge the current battery charging state based on the charging current I0; Step S302, if the charging state of the battery is normal, then based on the open-circuit voltage U of the battery oc , and the initial charging voltage U0 and charging current 10 of the charging pile, obtain the initial equivalent resistance R of the battery bat , which is specifically implemented by the following calculation method:

8. A method for limiting the output power of a charging pile based on battery dynamic parameters according to claim 7, characterized in that, The step S301 specifically includes the following steps: If it is detected that the value of the charging current I0 is 0, determine that the current battery charging state is in an abnormal condition, and immediately trigger the sending mechanism of the warning information. Otherwise, determine that the current battery charging state is in a normal state.

9. A method for limiting the output power of a charging pile based on battery dynamic parameters according to any one of claims 1-4, 6 or 8, characterized in that: The range of the first sampling period T1 is 1 - 5s.

10. A system using a method for limiting the output power of a charging pile based on battery dynamic parameters as described in any one of claims 1-9, characterized in that, At least include: The power grid monitoring module is used to obtain the power supply capacity P of the power grid in real time grid and set the maximum output power P of the charging pile based on the power supply capacity P of the power grid grid max ;​ The data acquisition module includes at least a voltage sensor and a current sensor, and is used to collect the open-circuit voltage U of the battery oc , the initial charging voltage U0 and charging current I0 of the charging pile, as well as the real-time charging voltage U and charging current I, and transmit the collected data to the data processing module; A data processing module, for calculating the equivalent resistance R of the battery based on the open-circuit voltage U of the battery oc , the initial charging voltage U0 and the charging current I0 of the charging pile bat , and for calculating the maximum allowable current I of the charging pile based on the maximum output power P max , the equivalent resistance R of the battery bat and the open-circuit voltage U of the battery oc ; max ​ A vehicle communication module, configured to receive a charging current I requested by the vehicle req and transmit it to the control module; The control module, based on the charging current I requested by the vehicle req and the maximum allowable current I of the charging pile max , outputs a control signal according to the following logic: If the said I req is greater than the said I max , then set the charging current I of the current charging pile to I max , otherwise set the charging current I of the current charging pile to I req ; The battery dynamic parameter update module is used to periodically collect the real-time charging voltage U and charging current I based on the first sampling period T1, and update the battery open-circuit voltage U based on the real-time charging voltage U and charging current I oc and the battery equivalent resistance R bat , and transmit the updated battery open-circuit voltage U oc and the battery equivalent resistance R bat to the data processing module; A power output module, used to dynamically adjust the charging current I of the charging pile based on the control signal of the control module.

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