Intelligent charging security early warning and alarming system for electric vehicle

Abstract

The invention relates to the technical field of intelligent charging early warning, and discloses an electric vehicle intelligent charging security early warning alarm system, which comprises a charging data acquisition module used for acquiring the charging voltage of an electric vehicle during charging, analyzing and processing the charging voltage of the electric vehicle during charging and the rated voltage of an electric vehicle battery to obtain a charging voltage difference, and sending the charging voltage difference to an early warning module; the system comprises a monitoring module for monitoring the charging voltage difference when the electric vehicle is charged and processing and analyzing the charging voltage difference to obtain an over-limit early warning value, an over-limit early warning judgment module for judging whether charging over-limit early warning needs to be carried out when the electric vehicle is charged according to the over-limit early warning value, and a charging fluctuation analysis module for constructing a voltage difference change curve according to the charging voltage difference when the electric vehicle is charged in a monitoring period, the charging fluctuation early warning module is used for establishing a positive and negative voltage difference interval and processing and analyzing the voltage difference change curve and the established positive and negative voltage difference interval to obtain a charging fluctuation performance value, and the fluctuation early warning module is used for judging whether charging fluctuation early warning needs to be carried out when the electric vehicle is charged or not according to the charging fluctuation performance value.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent charging early warning, and in particular to an intelligent charging security early warning alarm system for electric vehicles. Background Art

[0002] With the vigorous development of new energy technologies, new energy vehicles have been integrated into human life. Electric vehicles have become an important means of transportation for humans. Solving some of the risks of charging electric vehicles is conducive to promoting the vigorous development of electric vehicles. In the prior art, the existing electric vehicle charging security system only relies on a single voltage or current threshold for early warning, lacks a comprehensive analysis and evaluation of voltage fluctuations during the charging process, resulting in insufficient accuracy of the early warning and prone to false alarms or missed alarms. Due to the lack of a comprehensive analysis mechanism for multiple charging data, the existing system cannot issue an accurate early warning signal when a charging anomaly occurs, resulting in an ambiguous response. Users cannot judge the specific abnormal situation through the early warning, increasing safety risks. The data processing flow of the existing system is single, and it is impossible to conduct a comprehensive analysis and processing of the charging data, and it is impossible to conduct a multi-faceted analysis of the abnormal situation, and it is impossible to accurately analyze and warn the fluctuations generated during the charging process. Due to the inaccurate and untimely early warning, the existing system cannot understand the specific dynamic situation of charging, which affects the user's charging experience and reduces user satisfaction. Summary of the invention

[0003] The purpose of the present invention is to provide an electric vehicle intelligent charging security early warning alarm system. In order to solve the above-mentioned prior art problems, the present invention is implemented through the following technical solutions: The present invention provides an electric vehicle intelligent charging security early warning alarm system, comprising the following modules: Charging data acquisition module: obtains the charging voltage of the electric vehicle during charging through the BMS, analyzes and processes the charging voltage of the electric vehicle during charging and the rated voltage of the electric vehicle battery to obtain the charging voltage difference. During the monitoring period, the charging voltage difference of the electric vehicle during charging is monitored in real time, and the average duration ratio, average interval time ratio and voltage difference constant are analyzed and analyzed to obtain the over-limit warning value. Out-of-bounds warning judgment module: according to the out-of-bounds warning value, it is determined whether it is necessary to issue an out-of-bounds warning for the electric vehicle when charging; Charging fluctuation analysis module: Based on the charging not exceeding the limit signal, the voltage difference change curve is constructed according to the charging voltage difference when the electric vehicle is charging during the monitoring period, and the positive and negative voltage difference intervals are established according to the charging voltage difference standard range. The voltage difference change curve and the established positive and negative voltage difference intervals are processed and analyzed to obtain the wave point group ratio, voltage deviation ratio and change zone time ratio, and the charging fluctuation performance value is obtained through comprehensive analysis; Fluctuation warning module: According to the charging fluctuation performance value, it is determined whether it is necessary to issue a charging fluctuation warning to the electric vehicle when charging.

[0004] Beneficial effects of the present invention: 1. Intuitively analyze the difference between the charging voltage and the rated voltage of the electric vehicle. During the monitoring period, the charging voltage difference of the electric vehicle is monitored in real time. The average duration ratio, average interval time ratio and voltage difference constant are analyzed and analyzed to obtain the over-limit warning value. According to the over-limit warning value, it is determined whether it is necessary to issue an over-limit warning for the electric vehicle during charging. The charging data is monitored in real time, and the time when the abnormal situation occurs is statistically analyzed, which is conducive to analyzing and judging the persistence and severity of the abnormality. The degree of voltage deviation and the duration of the abnormality are intuitively observed, so as to facilitate timely warning to remind users to take timely measures to protect the safety of electric vehicle charging.

[0005] 2. By analyzing the fluctuation of charging voltage during charging, detecting and evaluating the fluctuation performance of charging voltage, it is helpful to analyze and judge the stability of electric vehicle charging during the charging process. The safety of electric vehicle charging can be reasonably analyzed through the size and continuity of charging voltage fluctuation. It helps users to judge the fluctuation of charging behavior during the charging process, and receive early warning signals in time when abnormalities occur, so as to prevent charging behavior from causing further damage to the electric vehicle and improve the user's charging experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. Figure 1 This is a flow chart of the steps of an electric vehicle intelligent charging security early warning alarm system provided by the present invention; Figure 2 It is a system block diagram of an electric vehicle intelligent charging security early warning alarm system provided by the present invention. DETAILED DESCRIPTION

[0007] In order to enable persons skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present invention. Embodiment 1: Figure 1This is a flow chart of an electric vehicle intelligent charging security warning alarm system provided by Embodiment 1 of the present invention. An electric vehicle intelligent charging security warning alarm system provided by an embodiment of the present invention specifically includes: Charging data acquisition module: obtains the charging voltage of the electric vehicle during charging through the BMS, analyzes and processes the charging voltage of the electric vehicle during charging and the rated voltage of the electric vehicle battery to obtain the charging voltage difference. During the monitoring period, the charging voltage difference of the electric vehicle during charging is monitored in real time, processed and analyzed, and an out-of-bounds warning value is obtained; It should be noted that BMS stands for battery management system, which monitors the voltage, current and temperature of electric vehicle batteries in real time to accurately understand the working status of the batteries; Specifically, the charging voltage of the electric vehicle during charging is obtained, and the charging voltage of the electric vehicle during charging is processed with the rated voltage of the battery of the electric vehicle to obtain the charging voltage difference; Compare the charging voltage difference when the electric vehicle is charged with the charging voltage difference standard range; If the charging voltage difference during charging of the electric vehicle is within the charging voltage difference standard range, a voltage difference normal signal is generated; If the charging voltage difference during charging of the electric vehicle is within the charging voltage difference standard range, a voltage difference abnormality signal is generated; During the monitoring period, the number of times the voltage difference abnormal signal is generated and the duration of each generation of the voltage difference abnormal signal are recorded, the duration of each generation of the voltage difference abnormal signal is summed up to obtain the total generation time of the voltage difference abnormal signal, the total generation time of the voltage difference abnormal signal is ratioed with the number of times the voltage difference abnormal signal is generated to obtain the average duration of the voltage difference abnormal signal, the average duration of the voltage difference abnormal signal is ratioed with the time corresponding to the monitoring period to obtain the average duration ratio, which is recorded as CX; During the monitoring period, the interval time between adjacent voltage difference abnormal signals is recorded, the interval time between all adjacent voltage difference abnormal signals is summed up to obtain the total interval time of the voltage difference normal signals, the number of intervals between the voltage difference normal signals is counted, and the total interval time of the voltage difference normal signals is ratioed to the number of intervals between the voltage difference normal signals to obtain the average interval time ratio, which is recorded as JG; The period when the voltage difference normal signal appears is marked as the voltage difference normal period, and the voltage difference normal period is divided into several sub-periods of equal time length. The transition time nodes between adjacent sub-periods are used as collection points, and the charging voltage difference at the collection point is obtained, and the difference is processed with the adjacent and nearest charging voltage difference standard range endpoint value to obtain the charging voltage relative difference, and the charging voltage relative difference is processed with the adjacent and nearest charging voltage difference standard range endpoint value to obtain the charging voltage relative difference ratio at the collection point, and the charging voltage relative difference ratios at all collection points are summed and averaged to obtain the voltage difference constant value, which is recorded as YC; It should be noted that the transition time nodes between adjacent sub-periods are expressed as collection points: assuming that the voltage difference is often 1.00-3.00, it is divided into two sub-periods of 1.00-2.00 and 2.00-3.00, then the transition time node is 2.00; assuming that the voltage difference is often 1.00-3.00 and 4.00-5.00, it is divided into sub-periods of 30 minutes, then the transition time nodes are 1.30, 2.00, 2.30, 4.30; The obtained average duration ratio CX, average interval time ratio JG and voltage difference constant YC are processed by the formula: Obtain the over-limit warning value CY, where s1, s2 and s3 are all preset proportional coefficients; Out-of-bounds warning judgment module: according to the out-of-bounds warning value, it is determined whether it is necessary to issue an out-of-bounds warning for the electric vehicle when charging; Specifically, the out-of-bounds warning value is compared with the out-of-bounds warning threshold: If the over-limit warning value is greater than the over-limit warning threshold, it means that it is necessary to issue a charging over-limit warning to the electric vehicle during charging, and generate an over-limit warning signal; If the over-limit warning value is less than or equal to the over-limit warning threshold, it means that there is no need to issue a charging over-limit warning to the electric vehicle during charging, and a charging not over-limit signal is generated; Based on the over-limit warning signal, an over-limit warning is issued to the electric vehicle during charging; It should be noted that the meaning of the over-limit warning signal and the overall meaning of the charging over-limit warning is: when the charging voltage of the electric vehicle exceeds the preset safety range or standard value, that is, the over-limit warning threshold, the system detects the over-limit warning and triggers the corresponding warning mechanism, that is, the over-limit warning signal, according to the comparison result; The technical solution of the embodiment of the present invention is: obtaining the charging voltage of the electric vehicle during charging through the BMS, analyzing and processing the charging voltage of the electric vehicle during charging and the rated voltage of the electric vehicle battery, and obtaining the charging voltage difference, which is conducive to intuitively analyzing the difference between the charging voltage and the rated voltage of the electric vehicle, and monitoring the charging voltage difference of the electric vehicle during charging in real time within the monitoring period, analyzing and obtaining the average duration ratio, the average interval time ratio and the voltage difference constant, and processing and analyzing to obtain the over-limit warning value, and judging whether it is necessary to issue a charging over-limit warning for the electric vehicle during charging according to the over-limit warning value, monitoring the charging data in real time, and statistically analyzing the time when the abnormal situation occurs, which is conducive to analyzing and judging the persistence and severity of the abnormality, and intuitively observing the voltage deviation degree and the abnormal duration, so as to facilitate timely warning to remind users to take timely measures to protect the safety of electric vehicle charging.

[0008] Example 2: Figure 1 As shown, based on Example 1, an electric vehicle intelligent charging security early warning alarm system provided by the embodiment of the present invention includes: Charging fluctuation analysis module: Based on the charging not exceeding the limit signal, the voltage difference change curve is constructed according to the charging voltage difference when the electric vehicle is charging during the monitoring period, and the positive and negative voltage difference intervals are established according to the charging voltage difference standard range. The voltage difference change curve and the established positive and negative voltage difference intervals are processed and analyzed to obtain the charging fluctuation performance value; Wherein, the positive and negative voltage difference interval includes a positive voltage difference interval and a negative voltage difference interval; Specifically, an XY two-dimensional coordinate system is established with the time corresponding to the monitoring period as the X-axis and the charging voltage difference as the Y-axis; In the XY two-dimensional coordinate system, the charging voltage differences at different times in the monitoring period are marked and connected to obtain a voltage difference variation curve; Taking the two endpoint values ​​of the charging voltage difference standard range as reference values, constructing a reference line in the XY two-dimensional coordinate system, wherein the reference line includes a first reference line and a second reference line, the endpoint value corresponding to the first reference line is the maximum value within the charging voltage difference standard range, and the endpoint value corresponding to the second reference line is the minimum value within the charging voltage difference standard range; Marking the interval enclosed by the first reference line and the X-axis as a positive voltage difference interval; Marking the interval enclosed by the second reference line and the X-axis as a negative voltage difference interval; Integrate the peak points and trough points on the voltage difference change curve, specifically: integrate adjacent peak points and trough points into a point group; Based on any wave point group; If the wave peak point and the wave valley point in the wave point group are not in the same positive and negative voltage difference interval, the wave point group is marked as a variable area wave point group; If the peak point and the trough point in the wave point group are in the same positive and negative voltage difference interval, the wave point group is marked as a non-variable area wave point group; The number of variable area wave point groups is counted and the ratio is processed with the total number of wave point groups to obtain the ratio of variable area wave point groups and marked as BQ; Based on any variable zone wave point group; Obtain the charging voltage difference corresponding to the peak point and the charging voltage difference corresponding to the trough point in the wave point group, perform difference processing, and take the absolute value of the difference to obtain the voltage deviation difference corresponding to the variable area wave point group; The voltage deviation differences corresponding to all the wave point groups in the transformer area are summed up and averaged to obtain the mean value of the voltage deviation difference. The mean value of the voltage deviation difference is ratioed with the maximum value of the voltage deviation difference to obtain the voltage deviation ratio, which is marked as DP. The maximum voltage deviation difference is obtained by taking the absolute value of the difference between the two end points of the standard range of the charging voltage difference; Based on any variable zone wave point group; Obtain the time point corresponding to the peak point and the time point corresponding to the trough point in the variable area wave point group, perform difference processing, and obtain the variable area time of the variable area wave point group; sum and average the variable area time of all variable area wave point groups to obtain the mean of the variable area time; perform ratio processing on the mean of the variable area time and the time corresponding to the monitoring period to obtain the variable area time ratio, and mark it as BS; The obtained area change wave point group ratio BQ, voltage deviation ratio DP and area change time ratio BS are processed by data, and the formula is: Obtaining a charging fluctuation performance value BD, wherein a1, a2, and a3 are all preset proportional coefficients; Fluctuation warning module: According to the charging fluctuation performance value, it is determined whether it is necessary to issue a charging fluctuation warning to the electric vehicle during charging; Specifically, the charging fluctuation performance value is compared with the charging fluctuation performance threshold; If the charging fluctuation performance value is greater than the charging fluctuation performance threshold, it means that a charging fluctuation warning needs to be issued to the electric vehicle during charging, and a charging fluctuation warning signal is generated; If the charging fluctuation performance value is less than or equal to the charging fluctuation performance threshold, it means that there is no need to issue a charging fluctuation warning for the electric vehicle when charging; Based on the charging fluctuation warning signal, the electric vehicle is warned of charging fluctuations during charging; It should be noted that the meaning of the charging fluctuation warning signal and the overall meaning of the charging fluctuation warning is: through real-time monitoring and evaluation of the fluctuation performance of the electric vehicle charging process, when it is found that the fluctuation performance exceeds the normal range, a warning signal is generated in time and corresponding warning measures are taken to ensure the safety of the charging process and the performance stability of the electric vehicle; The technical solution of the embodiment of the present invention is: based on the charging not exceeding the limit signal, a voltage difference change curve is constructed according to the charging voltage difference when the electric vehicle is charging within the monitoring period, and a positive and negative voltage difference interval is established according to the charging voltage difference standard range, and the voltage difference change curve and the established positive and negative voltage difference interval are processed and analyzed to obtain the wave point group ratio, voltage deviation ratio and variable area time ratio, and a charging fluctuation performance value is obtained by comprehensive analysis. According to the charging fluctuation performance value, it is determined whether it is necessary to issue a charging fluctuation warning to the electric vehicle when charging. By analyzing the fluctuation of the charging voltage during charging, the fluctuation performance of the charging voltage is detected and evaluated, which is conducive to analyzing and judging the charging stability of the electric vehicle during the charging process. The safety of the electric vehicle charging is reasonably analyzed by the size and continuity of the charging voltage fluctuation, which helps users to judge the fluctuation of the charging behavior during the charging process, and receive warning signals in time when abnormalities occur, so as to prevent the charging behavior from causing further damage to the electric vehicle and improve the user's charging experience.

[0009] Example 3: Figure 1 As shown, based on Example 1 and Example 2, an electric vehicle intelligent charging security early warning alarm method provided by an embodiment of the present invention includes: The charging voltage of the electric vehicle is obtained through the BMS, and the charging voltage of the electric vehicle and the rated voltage of the battery of the electric vehicle are analyzed and processed to obtain the charging voltage difference; During the monitoring period, the charging voltage difference of electric vehicles is monitored in real time, and the average duration ratio, average interval time ratio and voltage difference constant are analyzed and processed comprehensively to obtain the over-limit warning value; According to the over-limit warning value, it is determined whether it is necessary to issue an over-limit warning for the electric vehicle during charging; Based on the charging-not-exceeding-limit signal, a voltage difference change curve is constructed according to the charging voltage difference when the electric vehicle is charging during the monitoring period, and a positive and negative voltage difference interval is established according to the charging voltage difference standard range. The voltage difference change curve and the established positive and negative voltage difference intervals are processed and analyzed to obtain the wave point group ratio, voltage deviation ratio and change zone time ratio, and the charging fluctuation performance value is obtained through comprehensive analysis; According to the charging fluctuation performance value, it is determined whether it is necessary to issue a charging fluctuation warning to the electric vehicle when charging.

[0010] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0011] A person of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0012] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. An electric vehicle intelligent charging security early warning alarm system, characterized in that: The following steps are involved: Charging data acquisition module: obtains the charging voltage of the electric vehicle during charging through the BMS, analyzes and processes the charging voltage of the electric vehicle during charging and the rated voltage of the electric vehicle battery to obtain the charging voltage difference. During the monitoring period, the charging voltage difference of the electric vehicle during charging is monitored in real time, and the average duration ratio, average interval time ratio and voltage difference constant are analyzed and analyzed to obtain the over-limit warning value. Out-of-bounds warning judgment module: according to the out-of-bounds warning value, it is determined whether it is necessary to issue an out-of-bounds warning for the electric vehicle when charging; Charging fluctuation analysis module: Based on the charging not exceeding the limit signal, the voltage difference change curve is constructed according to the charging voltage difference when the electric vehicle is charging during the monitoring period, and the positive and negative voltage difference intervals are established according to the charging voltage difference standard range. The voltage difference change curve and the established positive and negative voltage difference intervals are processed and analyzed to obtain the wave point group ratio, voltage deviation ratio and change zone time ratio, and the charging fluctuation performance value is obtained through comprehensive analysis; Fluctuation warning module: Based on the charging fluctuation performance value, determine whether it is necessary to issue a charging fluctuation warning to the electric vehicle when charging.

2. According to claim 1, an electric vehicle intelligent charging security early warning alarm system is characterized in that: The specific method of obtaining the charging voltage difference is: Obtaining the charging voltage of the electric vehicle when it is charging, performing difference processing on the charging voltage of the electric vehicle when it is charging and the rated voltage of the battery of the electric vehicle to obtain the charging voltage difference; Compare the charging voltage difference when the electric vehicle is charged with the charging voltage difference standard range; If the charging voltage difference during charging of the electric vehicle is within the charging voltage difference standard range, a voltage difference normal signal is generated; If the charging voltage difference during charging of the electric vehicle is within the charging voltage difference standard range, a voltage difference abnormality signal is generated.

3. The electric vehicle intelligent charging security early warning alarm system according to claim 1 is characterized in that: The specific process of obtaining the average duration ratio and the average interval time ratio is as follows: During the monitoring period, the number of times the voltage difference abnormal signal is generated and the duration of each generation of the voltage difference abnormal signal are recorded, the duration of each generation of the voltage difference abnormal signal is summed up to obtain the total generation time of the voltage difference abnormal signal, the total generation time of the voltage difference abnormal signal is ratioed with the number of times the voltage difference abnormal signal is generated to obtain the average duration of the voltage difference abnormal signal, the average duration of the voltage difference abnormal signal is ratioed with the time corresponding to the monitoring period to obtain the average duration ratio, which is recorded as CX; During the monitoring period, the interval time between adjacent voltage difference abnormal signals is recorded, the interval time between all adjacent voltage difference abnormal signals is summed up to obtain the total interval time of the voltage difference abnormal signals, the number of intervals between the voltage difference abnormal signals is counted, and the total interval time of the voltage difference abnormal signals is ratioed with the number of intervals between the voltage difference abnormal signals to obtain the average interval time ratio, which is recorded as JG.

4. The electric vehicle intelligent charging security early warning alarm system according to claim 1 is characterized in that: The specific processing process of the voltage difference constant is as follows: The time period when the voltage difference normal signal appears is marked as the voltage difference normal period, and the voltage difference normal period is divided into several sub-periods of equal time length. The transition time nodes between adjacent sub-periods are taken as collection points, and the charging voltage difference at the collection point is obtained. The difference is processed with the nearest adjacent charging voltage difference standard range endpoint value to obtain the charging voltage relative difference. The charging voltage relative difference is processed with the nearest adjacent charging voltage difference standard range endpoint value to obtain the charging voltage relative difference ratio at the collection point. The charging voltage relative difference ratios at all collection points are summed and averaged to obtain the voltage difference constant value, which is recorded as YC.

5. The electric vehicle intelligent charging security early warning alarm system according to claim 1 is characterized in that: The specific process of obtaining the out-of-bounds warning value is as follows: The obtained average duration ratio CX, average interval time ratio JG and voltage difference constant YC are processed by the formula: The over-limit warning value CY is obtained, wherein s1, s2 and s3 are all preset proportional coefficients, which is helpful for the system to analyze and determine whether it is necessary to issue a charging over-limit warning for the electric vehicle when charging.

6. The electric vehicle intelligent charging security early warning alarm system according to claim 1 is characterized in that: The specific processing process of the out-of-bounds warning signal is as follows: Compare the out-of-bounds warning value with the out-of-bounds warning threshold: If the over-limit warning value is greater than the over-limit warning threshold, it means that it is necessary to issue a charging over-limit warning to the electric vehicle during charging, and generate an over-limit warning signal; If the over-limit warning value is less than or equal to the over-limit warning threshold, it means that there is no need to issue a charging over-limit warning to the electric vehicle during charging, and a charging not over-limit signal is generated; Based on the over-limit warning signal, an over-limit charging warning is issued to the electric vehicle during charging.

7. The electric vehicle intelligent charging security early warning alarm system according to claim 1 is characterized in that: The specific process of obtaining the wave point group proportion and voltage deviation ratio is as follows: The positive and negative voltage difference interval includes a positive voltage difference interval and a negative voltage difference interval; In the XY two-dimensional coordinate system, the charging voltage differences at different times in the monitoring period are marked and connected to obtain a voltage difference variation curve; Integrate adjacent peak points and trough points into a wave point group; If the peak point and the trough point in the wave point group are not in the same positive and negative voltage difference interval, the wave point group is marked as a variable area wave point group; If the peak point and the trough point in the wave point group are in the same positive and negative voltage difference interval, the wave point group is marked as a non-variable area wave point group; The number of variable area wave point groups is counted and the ratio is processed with the total number of wave point groups to obtain the ratio of variable area wave point groups and marked as BQ; Obtain the charging voltage difference corresponding to the peak point and the charging voltage difference corresponding to the trough point in the wave point group, perform difference processing, and take the absolute value of the difference to obtain the voltage deviation difference corresponding to the variable area wave point group; The voltage deviation differences corresponding to all the wave point groups in the variable area are summed up and averaged to obtain the mean voltage deviation difference. The mean voltage deviation difference is ratioed with the maximum voltage deviation difference to obtain the voltage deviation ratio, which is marked as DP.

8. The electric vehicle intelligent charging security early warning alarm system according to claim 1 is characterized in that: The specific acquisition process of the variable zone time ratio is as follows: Based on any variable zone wave point group; Get the time point corresponding to the peak point and the time point corresponding to the trough point in the variable area wave point group, and perform difference processing to obtain the variable area time of the variable area wave point group, sum and average the variable area times of all variable area wave point groups to obtain the mean of the variable area time, perform ratio processing on the mean of the variable area time and the time corresponding to the monitoring period to obtain the variable area time ratio, and mark it as BS.

9. The electric vehicle intelligent charging security early warning alarm system according to claim 1 is characterized in that: The specific process of obtaining the charging fluctuation performance value is as follows: The obtained area change wave point group ratio BQ, voltage deviation ratio DP and area change time ratio BS are processed by data, and the formula is: A charging fluctuation performance value BD is obtained, wherein a1, a2 and a3 are all preset proportional coefficients.

10. The electric vehicle intelligent charging security early warning alarm system according to claim 1, characterized in that: The specific processing process of the charging fluctuation warning signal is as follows: comparing the charging fluctuation performance value with a charging fluctuation performance threshold; If the charging fluctuation performance value is greater than the charging fluctuation performance threshold, it means that a charging fluctuation warning is required for the electric vehicle when charging, a charging fluctuation warning signal is generated, and a charging fluctuation warning is issued to the electric vehicle when charging.

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