A test process control method for a vehicle-mounted electric power test bench based on working condition self-recognition

Abstract

The application discloses a kind of based on self-identification of working condition vehicle-mounted electric power test bench test process control method, it is related to process control technical field, for solving the problem of transient stage misjudgment and protection malfunction occurrence probability increases, by introducing multiple physical sensors in vehicle-mounted electric power test bench, on the basis of current loop signal in the initial stage of vehicle power-on, power-on trigger condition is judged, in the working condition identification stage, the voltage climbing coefficient is calculated by the bus current change characteristic, the pre-charging working condition is quantitatively identified, in the pre-charging working condition, further combined with the AC ripple mutation index and current change spike feature, the main relay switching transient is identified, after relay switching, whether bus electrical state reaches steady-state requirement or whether secondary working condition identification needs to be executed is judged by the comprehensive evaluation of current disturbance energy and ripple proportion, by the working condition identification mechanism of multiple parameters in stages, avoid transient stage misjudgment and protection malfunction.

Description

Technical Field

[0001] This invention relates to the field of process control technology, and more specifically, to a test process control method for an on-board power test bench based on self-identification of operating conditions. Background Technology

[0002] With the rapid development of new energy vehicle technology, the safety and reliability of the vehicle's high-voltage electrical system have become an important part of vehicle testing and verification. In actual testing, due to the complex characteristics of the transient phase, traditional testing procedures are difficult to distinguish the subdivided operating conditions in a timely and accurate manner. Especially when the vehicle is powered on for the first time or the high-voltage system architecture is updated, transient current spikes and ripple changes may cause the test bench to misjudge the steady-state operating condition, thereby prematurely triggering power or efficiency test items, or malfunctioning protection mechanisms, resulting in distorted test data, increased repeated testing, or even risks to test equipment.

[0003] The existing technology has the following shortcomings: Currently, existing technologies mainly rely on manually preset test procedures and fixed threshold judgment methods, lacking the ability to automatically identify operating conditions and dynamically adapt control the entire high-voltage power-on process of the vehicle. This makes it difficult to distinguish between subdivided operating conditions such as the pre-charging stage, the main relay closing stage, and the steady-state power supply stage, leading to an increased probability of transient false tests and protection malfunctions. This can prematurely trigger power or efficiency test items, and also easily cause test bench protection malfunctions when current spikes or ripple changes are large. Therefore, this paper proposes a test process control method for an on-board power test bench based on self-identification of operating conditions.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a test process control method for an on-board power test bench based on operating condition self-identification. This method utilizes current sensors, bus ripple sampling sensors, and voltage slope sensors, combined with operating condition discrimination feature vector construction and dynamic threshold identification mechanisms, to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a test process control method for an on-board power test bench based on working condition self-identification, comprising the following steps: Step S1: Use the vehicle power test bench to monitor the vehicle under test, collect the current loop signal of the vehicle under test, analyze the power-on status of the vehicle under test based on the current loop signal, and determine whether the working condition identification mechanism has been entered. Step S2: In the working condition identification mechanism, set the identification period, detect the bus current data and AC ripple data of the vehicle under test within the identification period, calculate the voltage ramp-up coefficient based on the bus current data and determine whether the vehicle under test is in the pre-charging working condition. Step S3: When the vehicle under test is in the pre-charging condition, generate a ripple mutation index based on the AC ripple data, detect the current change amplitude and statistically analyze the change peak characteristics, and analyze the relay switching status of the vehicle under test in combination with the ripple mutation index. Step S4: Based on the relay switching state, select to stop the test or collect the current disturbance energy and ripple ratio of the vehicle under test, and determine whether to perform secondary operating condition identification on the vehicle under test by combining the current disturbance energy and ripple ratio.

[0007] In a preferred embodiment, in step S1, the current circuit signal of the vehicle under test is collected by a current sensor arranged in the output circuit of the vehicle power test bench. The current loop signal is a sampling sequence of actual current values ​​that change over time. Its physical meaning is the magnitude of the instantaneous conduction current in the loop during the process of the on-board power test bench supplying power to the vehicle under test. Within the preset sampling period, the vehicle-mounted power test bench continuously samples the current loop signal at the preset sampling period.

[0008] In a preferred embodiment, in step S1, when the amplitude of the current loop signal remains at zero within a preset sampling period, it indicates that the loop of the vehicle under test has not been established and the vehicle under test is in an unpowered state. When the current loop signal remains non-zero for at least one consecutive sampling period and does not fall back to zero in the next sampling period, the current loop signal is determined to have a continuous characteristic. When the current loop signal simultaneously switches from zero to non-zero and does not exhibit continuous characteristics in subsequent continuous sampling periods, the vehicle under test is determined to be in a powered-on state and enters the operating condition identification mechanism. Conversely, maintain the current monitoring status and do not enter the operating condition identification mechanism.

[0009] In a preferred embodiment, in step S2, after entering the working condition identification mechanism, an identification period for working condition determination is set, and the bus current data and AC ripple data of the vehicle under test are synchronously detected within the identification period. Bus current data reflects the actual conduction current on the bus during the process of the on-board power test bench supplying power to the vehicle under test; The AC ripple data is the amplitude of the AC component superimposed on the bus voltage, which is acquired by a ripple sampling sensor located on the bus output circuit side.

[0010] In a preferred embodiment, in step S2, a bus current data sequence is constructed in chronological order from the bus current data obtained by continuous sampling within the identification period; Based on the constructed bus current data sequence, the change in bus current between adjacent sampling points is calculated to obtain the bus current change rate. The voltage ramp-up coefficient is calculated by statistically processing the rate of change of current of each bus during the identification period. When the voltage ramp-up coefficient is less than or equal to the preset ramp-up judgment threshold, the bus voltage is judged to be in a slow build-up state, and the corresponding vehicle under test is in a pre-charging state. When the voltage ramp-up coefficient is greater than the preset ramp-up judgment threshold, it is determined that the bus voltage establishment process does not meet the pre-charging characteristics, and the vehicle under test is not in the pre-charging condition.

[0011] In a preferred embodiment, in step S3, when the vehicle under test is in the pre-charging condition, the AC ripple data are arranged in chronological order, and the difference between adjacent AC ripple data is calculated and the absolute value is taken to obtain the ripple difference value. The difference between the maximum and minimum values ​​of the ripple difference is used to obtain the ripple amplitude expansion. The ratio of the ripple amplitude expansion to the recognition period is used as the ripple mutation index. A preset sampling period is used to detect the high-voltage bus current through a Hall current sensor within the preset sampling period. The high-voltage bus currents are arranged in chronological order, and the absolute value of the difference between adjacent high-voltage bus currents is used to obtain the current change amplitude.

[0012] In a preferred embodiment, in step S3, the vehicle test record library is accessed to obtain samples of current change amplitudes during historical power-on processes, including each historical current change amplitude, and a current change peak reference is calculated based on each historical current change amplitude. If the current change amplitude is greater than the current change peak reference, it is determined to be a current change peak event. Conversely, it is not considered a current change spike event; The number of current change spike events is used as the change spike count, and the ratio of the change spike count to the preset sampling period is used as the change spike characteristic. The product of the standardized peak characteristics and the ripple mutation index is used as the switching joint index. If the switching joint index is greater than the preset switching joint threshold, the relay switching state is determined to be a relay switching occurrence state. Conversely, the relay switching state is determined to be a non-relay switching state.

[0013] In a preferred embodiment, in step S4, when the relay switching state is non-relay switching state, the current disturbance energy and ripple ratio of the vehicle under test are selected for acquisition. When the relay switching state is in the relay switching occurrence state, select Stop Test; When the relay switching state is non-relay switching state, a preset disturbance assessment period is set. Within the preset disturbance assessment period, the high-voltage bus current of the vehicle under test is continuously sampled, and the current change amplitude is calculated. The current disturbance energy is calculated based on the current change amplitude.

[0014] In a preferred embodiment, in step S4, the AC ripple data detected within the disturbance assessment period are arranged in chronological order, and the difference between adjacent AC ripple data is used to obtain the AC ripple change amplitude. If the amplitude of the previous AC ripple change is less than the amplitude of the next AC ripple change, then the amplitude of the next AC ripple change is marked. Conversely, the amplitude of AC ripple variation is not marked; The amplitude of adjacent marker AC ripple changes is combined into an AC ripple duration sequence, and the ripple ratio is calculated based on the time length corresponding to the AC ripple duration sequence. The current disturbance energy and ripple ratio are standardized separately to obtain the current disturbance coefficient and ripple ratio coefficient. The total disturbance coefficient is obtained by summing the current disturbance coefficient and the ripple ratio coefficient.

[0015] In a preferred embodiment, in step S4, the current disturbance weight and ripple ratio weight are calculated using the total disturbance coefficient. The disturbance intensity characteristics are further obtained by weighting the current disturbance weight and the ripple ratio weight with the current disturbance coefficient and the ripple ratio coefficient, respectively. If the disturbance intensity characteristic is greater than the preset disturbance intensity threshold, it is determined that the vehicle under test will undergo secondary operating condition identification. Conversely, if the condition is not specified, it will be determined that the vehicle under test will not undergo secondary condition identification.

[0016] The technical effects and advantages of this invention are as follows: This invention introduces multiple types of physical sensors into an on-board power test bench to achieve automated segmented identification of operating conditions and adaptive control of the testing process throughout the high-voltage power-on process. Using current sensors and bus ripple sampling sensors as core sensing units, the system determines the power-on trigger condition based on the current loop signal at the initial stage of vehicle power-on. During the operating condition identification phase, the voltage ramp-up coefficient is calculated based on the bus current change characteristics to quantitatively identify the pre-charge condition. Within the pre-charge condition, the system further combines the AC ripple mutation index and current change peak characteristics to identify the main relay switching transient. After the relay switching, a comprehensive evaluation of the current disturbance energy and ripple ratio determines whether the bus electrical state has reached steady-state requirements or whether a secondary operating condition identification is necessary. This multi-parameter, segmented operating condition identification mechanism avoids false measurements and protection malfunctions during transient phases, improving the effectiveness, consistency, and repeatability of on-board power test data. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the implementation of a test process control method for an on-board power test bench based on working condition self-identification according to the present invention.

[0018] Figure 2 This is a schematic diagram illustrating the steps of a test process control method for an on-board power test bench based on working condition self-identification according to the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention introduces multiple types of physical sensors into an on-board power test bench to achieve automatic segmented identification of operating conditions and adaptive control of the testing process throughout the high-voltage power-on process. Using current sensors and bus ripple sampling sensors as core sensing units, the invention determines the power-on trigger condition based on the current loop signal at the initial stage of vehicle power-on. During the operating condition identification phase, the voltage ramp-up coefficient is calculated based on the bus current change characteristics to quantitatively identify the pre-charge operating condition. Within the pre-charge operating condition, the invention further combines the AC ripple mutation index and current change peak characteristics to identify the main relay switching transient. After the relay switching, a comprehensive evaluation of the current disturbance energy and ripple ratio determines whether the bus electrical state has reached steady-state requirements or whether secondary operating condition identification is necessary, thus avoiding false measurements and protection malfunctions during the transient phase.

[0021] Examples, such as Figures 1 to 2 As shown, a test process control method for an on-board power test bench based on working condition self-identification includes the following steps: Step S1: Use the vehicle power test bench to monitor the vehicle under test, collect the current loop signal of the vehicle under test, analyze the power-on status of the vehicle under test based on the current loop signal, and determine whether the working condition identification mechanism has been entered. Step S2: In the working condition identification mechanism, set the identification period, detect the bus current data and AC ripple data of the vehicle under test within the identification period, calculate the voltage ramp-up coefficient based on the bus current data and determine whether the vehicle under test is in the pre-charging working condition. Step S3: When the vehicle under test is in the pre-charging condition, generate a ripple mutation index based on the AC ripple data, detect the current change amplitude and statistically analyze the change peak characteristics, and analyze the relay switching status of the vehicle under test in combination with the ripple mutation index. Step S4: Based on the relay switching state, select to stop the test or collect the current disturbance energy and ripple ratio of the vehicle under test, and determine whether to perform secondary operating condition identification on the vehicle under test by combining the current disturbance energy and ripple ratio.

[0022] The specific implementation is as follows: In step S1, the vehicle under test is monitored using an on-board power test bench. A current sensor located in the output circuit of the on-board power test bench acquires the current circuit signal of the vehicle under test. The current sensor is a Hall effect current sensor, installed between the output of the on-board power test bench and the interface of the vehicle under test, used to obtain the actual current value in the circuit in real time.

[0023] It should be noted that the vehicle-mounted power test bench is a specialized testing device used to simulate the actual power supply environment of a vehicle and to detect the vehicle's power status. It provides a controllable test power to the vehicle under test and monitors the electrical status during the power supply process in real time in the output circuit. The output circuit is the power supply path formed between the vehicle-mounted power test bench and the vehicle under test, and its electrical status directly reflects whether the vehicle under test has established a power supply circuit. The Hall effect current sensor works based on the Hall effect. It detects the changes in the magnetic field generated around the current-carrying conductor and converts the magnetic field signal into an electrical signal output that is proportional to the magnitude of the circuit current.

[0024] The current loop signal output by the current sensor is a sampling sequence of actual current values ​​that change over time. Its physical meaning is the magnitude of the instantaneous conduction current in the loop during the process of the on-board power test bench supplying power to the vehicle under test.

[0025] Within a preset sampling period, the vehicle-mounted power test bench continuously samples the current loop signal at the preset sampling period, and performs amplitude determination and time continuity analysis on the sampled current loop signal.

[0026] The amplitude of the current loop signal is used to reflect whether the loop has formed an effective conduction path. The larger the value, the higher the degree of conduction in the loop. When the amplitude of the current loop signal remains at zero within the preset sampling period, it indicates that the loop of the vehicle under test has not been established and the vehicle under test is in an unpowered state.

[0027] Specifically, based on the analysis of whether the amplitude of the current loop signal is zero, the maintenance status of the current loop signal in multiple consecutive sampling periods is further judged. When the current loop signal remains non-zero for at least one consecutive sampling period and does not fall back to zero in the next sampling period, the current loop signal is determined to have a continuous characteristic.

[0028] The persistence characteristic is used to distinguish transient interference current from real power-on current. The longer the duration, the higher the reliability of the power-on behavior of the vehicle under test.

[0029] When the current loop signal simultaneously switches from zero to non-zero and does not exhibit a continuous characteristic in subsequent continuous sampling periods, it is determined that the vehicle under test has entered the power-on state, and the triggering conditions for the entry into the working condition identification mechanism are met accordingly. If the above conditions are not met, the current monitoring status will be maintained and the operating condition identification mechanism will not be activated.

[0030] By using the current loop signal collected by the current sensor, the power-on status of the vehicle under test can be quantified and calculated, thus providing a clear and reliable starting basis for the subsequent working condition identification process.

[0031] In step S2, after entering the operating condition identification mechanism, the on-board power test bench sets an identification period for operating condition determination, and synchronously detects the bus current data and AC ripple data of the vehicle under test within the identification period.

[0032] The bus current data is obtained by a current sensor arranged in the bus output circuit of the vehicle power test bench. The current sensor is the same as the Hall current sensor used to collect the current circuit signal in step S1. The bus current data reflects the actual conduction current on the bus during the process of the vehicle power test bench supplying power to the vehicle under test. Its value is used to characterize the change state of the bus load. The larger the bus current data value, the larger the load currently carried by the bus.

[0033] AC ripple data is acquired by a ripple sampling sensor installed on the bus output circuit side, reflecting the variation characteristics of the superimposed AC component in the bus voltage. The AC ripple sampling sensor detects the AC component in the high-voltage bus voltage, and its output AC ripple data is the amplitude of the superimposed AC component in the bus voltage. The AC ripple data reflects the stability of the bus voltage; the smaller the amplitude, the more stable the bus voltage; the larger the amplitude, the stronger the fluctuation component in the bus voltage, indicating that the bus is in a non-steady-state state.

[0034] After collecting bus current data within the identification period, the voltage ramp-up coefficient is calculated based on the bus current data, and the vehicle under test is determined to be in pre-charging condition. The specific calculation process is as follows.

[0035] First, a bus current data sequence is constructed in chronological order from the continuously sampled bus current data obtained within the identification period. This bus current data sequence characterizes the change of the high-voltage bus current over time within the identification period, and its trend indirectly reflects the establishment process of the high-voltage bus voltage.

[0036] Based on the constructed bus current data sequence, the change in bus current between adjacent sampling points is calculated to obtain the bus current change rate. The bus current change rate reflects the degree of change of bus current per unit time. Its value characterizes the smoothness of the bus current change; the smaller the value of the bus current change rate, the smoother the bus current change.

[0037] Subsequently, the rate of change of each bus current within the identification period is statistically processed to calculate the voltage ramp-up coefficient. Specifically, the average of all bus current rate of change within the identification period is calculated to obtain the voltage ramp-up coefficient. The voltage ramp-up coefficient is a comprehensive indicator of the bus current rate of change within the identification period, used to reflect the ramp-up status of the bus voltage. The smaller the value of the voltage ramp-up coefficient, the more uniform the change of the bus current within the identification period, and the more stable the corresponding bus voltage ramp-up process; the larger the value of the voltage ramp-up coefficient, the larger the fluctuation of the bus current within the identification period, and the more severe the corresponding bus voltage ramp-up process.

[0038] After obtaining the voltage ramp-up coefficient, the voltage ramp-up coefficient is compared with the preset ramp-up judgment threshold. When the voltage ramp-up coefficient is less than or equal to the preset ramp-up judgment threshold, the bus voltage is judged to be in a slow build-up state, and the corresponding vehicle under test is in a pre-charging state. When the voltage ramp-up coefficient is greater than the preset ramp-up judgment threshold, it is determined that the bus voltage establishment process does not meet the pre-charging characteristics, and the vehicle under test is not in the pre-charging condition.

[0039] Through the above calculation process, the pre-charge condition can be quantified based on the bus current data, providing a clear basis for the identification of subsequent relay switching conditions.

[0040] It should be noted that the ramp-up threshold is a quantitative criterion used to distinguish between the slow voltage build-up process and the rapid voltage transition process of the bus. Its value is set by the on-board power test bench during the calibration phase based on the bus current change characteristics under typical pre-charge conditions. Specifically, during the test bench calibration phase, multiple sets of power-on test data confirmed to be in the pre-charge condition are collected, and the corresponding voltage ramp-up coefficients are calculated to form a coefficient sample set. The coefficient sample set is statistically analyzed, and the mean and standard deviation are calculated. The sum of the mean and standard deviation is used as the ramp-up threshold.

[0041] In step S3, when the vehicle under test is in the pre-charging condition, the AC ripple data are arranged in chronological order, and the difference between adjacent AC ripple data is calculated and the absolute value is taken to obtain the ripple difference value. The difference between the maximum and minimum values ​​of the ripple differential is used to obtain the ripple amplitude expansion. The ratio of the ripple amplitude expansion to the identification period is used as the ripple mutation index. The larger the ripple mutation index, the more drastic the change in the high-frequency electrical characteristics of the bus. A preset sampling period is set. Within the preset sampling period, the high-voltage bus current is detected by a Hall current sensor. The high-voltage bus currents are arranged in chronological order, and the absolute value of the difference between adjacent high-voltage bus currents is taken to obtain the current change amplitude. Access the vehicle test record library to obtain samples of current variation amplitudes during historical electrical processes. The current variation amplitude samples include the current variation amplitudes of each historical process. The median of the historical current variation is taken as the median of the current variation. The absolute value of the difference between the median of the current variation and the historical current variation is taken as the current amplitude deviation. The median of the current amplitude deviation is taken as the median of the current amplitude deviation. The current change peak reference is obtained by summing the median current change and the median current amplitude deviation, which reflects the level of current change amplitude during historical normal pre-charging and power-on processes. Compare the magnitude of current change with a current change peak reference to statistically analyze the characteristics of the change peak: If the current change amplitude is greater than the current change peak reference, it is determined to be a current change peak event. Conversely, it is not considered a current change spike event; The number of current change spike events is used as the change spike count. The ratio of the change spike count to the preset sampling period is used as the change spike characteristic, which reflects the degree of clustering of current changes exceeding the historical normal level under pre-charging conditions. The larger the value, the more frequently the current change exceeds the historical normal range. The change spike feature and ripple mutation index are standardized separately to obtain the change spike coefficient and ripple mutation coefficient. Specifically, the historical maximum and minimum values ​​of the change spike feature and ripple mutation index are obtained from the vehicle test record library, and the change spike feature and ripple mutation index are standardized using the Min-Max standardization method. The product of the change peak coefficient and the ripple mutation coefficient is used as the switching joint index; The switching joint index is compared with the preset switching joint threshold to analyze the relay switching status of the vehicle under test: If the switching joint index is greater than the preset switching joint threshold, the relay switching state of the vehicle under test is determined to be the relay switching occurrence state. Conversely, if the relay switching state of the vehicle under test is determined to be a non-relay switching state; When the switching joint index is greater than the preset switching joint threshold, it indicates that a switching action such as relay closing or opening has occurred; when the switching joint index is less than or equal to the preset switching joint threshold, it indicates that the current current and ripple changes are still in the continuous change range under the pre-charge condition, and no obvious relay switching characteristics have yet appeared.

[0042] It should be noted that the preset sampling period can be set according to the sampling frequency of the test bench and the bus voltage level; the Hall current sensor is a sensor that realizes non-contact current measurement based on the principle of magnetic field induction; the vehicle test record library is a database used to store historical vehicle high-voltage power-on test data; the standardization processing methods include, but are not limited to, standard linear transformation based on interval scaling, Z-Score standardization method based on statistics, or normalization method based on nonlinear mapping function. The application methods of standardization processing will not be elaborated here; the preset switching joint threshold can be set according to the statistical results of historical test data, the protection strategy of the test bench, or the relay response characteristics of different vehicle models. Specifically, the switching joint index corresponding to the actual switching time of multiple relays is extracted from the vehicle test record library and an index sample set is constructed. The mean and standard deviation of the index sample set are calculated, and the result of the mean minus the standard deviation is used as the switching joint threshold.

[0043] This step, based on the electrical physical quantities collected on the test bench, enables the identification of relay switching transients within the pre-charge condition, providing a clear basis for the operating condition status for subsequent test process control.

[0044] In step S4, when the relay switching state is the relay switching occurrence state, the test is stopped and the current disturbance energy and ripple ratio acquisition operations are not performed to avoid the test items with high power supply stability requirements being accidentally triggered during the relay switching transient phase. When the relay switching state is non-relay switching state, select to collect the current disturbance energy and ripple ratio of the vehicle under test. By quantitatively analyzing the cumulative degree of bus current disturbance and the abnormal occupancy ratio of bus ripple, further determine whether the vehicle under test needs to enter the secondary working condition identification process. A disturbance assessment period is preset. During the disturbance assessment period, the high-voltage bus current of the vehicle under test is continuously sampled and the amplitude of each current change is calculated. The current disturbance energy is obtained by squaring the current change amplitudes during the disturbance assessment period and summing them up, which reflects the cumulative intensity of the bus current disturbance in the time dimension after the relay switching. Acquire AC ripple data within the disturbance assessment period and arrange them in chronological order. Subtract adjacent AC ripple data to obtain the AC ripple variation amplitude, and combine the AC ripple variation amplitudes into an AC ripple variation sequence. In the AC ripple change sequence, if the amplitude of the previous AC ripple change is smaller than that of the next AC ripple change, then the amplitude of the next AC ripple change is marked; otherwise, the amplitude of the AC ripple change is not marked. The amplitude of adjacent marked AC ripple changes is combined into an AC ripple duration sequence. The time length corresponding to the AC ripple duration sequence is taken as the AC ripple duration period, reflecting the time span of continuous enhancement of bus ripple changes. The ratio of the sum of the duration of each AC ripple to the disturbance assessment period is taken as the ripple proportion. The larger the value, the higher the proportion of the bus ripple in a continuous changing state within the disturbance assessment period, and the greater the duration of ripple disturbance in the time dimension after relay switching. The current disturbance energy and ripple ratio are standardized separately to obtain the current disturbance coefficient and ripple ratio coefficient. Specifically, the historical maximum and minimum values ​​of current disturbance energy and ripple ratio are obtained from the vehicle test record library, and the Min-Max standardization method is used to standardize the current disturbance energy and ripple ratio. The total disturbance coefficient is obtained by summing the current disturbance coefficient and the ripple ratio coefficient. The ratio of the current disturbance coefficient to the total disturbance coefficient is used as the current disturbance weight, and the ratio of the ripple ratio coefficient to the total disturbance coefficient is used as the ripple ratio weight. After obtaining the current disturbance weight and ripple ratio weight, the current disturbance coefficient is multiplied by the current disturbance weight, the ripple ratio coefficient is multiplied by the ripple ratio weight, and the product results are summed to obtain the disturbance intensity characteristics. The disturbance intensity characteristic reflects the cumulative degree of deviation of the bus electrical parameters from the steady state after the relay switching. The larger the value, the higher the proportion of current disturbance and ripple disturbance in the evaluation period after switching, and the system is in a clear transient transition phase. The disturbance intensity characteristics are compared with a preset disturbance intensity threshold to determine whether secondary operating condition identification should be performed on the vehicle under test. If the disturbance intensity characteristic is greater than the preset disturbance intensity threshold, it is determined that the vehicle under test will undergo secondary operating condition identification. Conversely, if the condition is not specified, it will be determined that the vehicle under test will not undergo secondary condition identification.

[0045] It should be noted that the preset disturbance assessment period is used to limit the decay time of the bus electrical disturbance after relay switching, which can be limited according to the duration of the relay switching transient and the time range required for the bus electrical parameters to recover to a steady state; the preset disturbance intensity threshold can be limited according to the statistical results of the disturbance after switching in the historical vehicle test records. Specifically, the corresponding disturbance intensity characteristics are calculated in multiple sets of samples that have completed relay switching and entered a steady state, and a feature sample set is constructed. The mean and standard deviation of the feature sample set are calculated, and the sum of the mean and standard deviation is used as the disturbance intensity threshold.

[0046] Finally, it should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0047] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0048] In this document, the singular forms “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that terms such as “comprising / including” or “having” specify the presence of the stated features, integrals, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integrals, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0049] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0050] The above description of the disclosed embodiments will enable those skilled in the art to make or use various modifications to these embodiments. It will be readily apparent to those skilled in the art that the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A test process control method for an on-board power test bench based on self-identification of operating conditions, characterized in that: Includes the following steps: Step S1: Use the vehicle power test bench to monitor the vehicle under test, collect the current loop signal of the vehicle under test, analyze the power-on status of the vehicle under test based on the current loop signal, and determine whether the working condition identification mechanism has been entered. Step S2: In the working condition identification mechanism, set the identification period, detect the bus current data and AC ripple data of the vehicle under test within the identification period, calculate the voltage ramp-up coefficient based on the bus current data and determine whether the vehicle under test is in the pre-charging working condition. Step S3: When the vehicle under test is in the pre-charging condition, generate a ripple mutation index based on the AC ripple data, detect the current change amplitude and statistically analyze the change peak characteristics, and analyze the relay switching status of the vehicle under test in combination with the ripple mutation index. Step S4: Based on the relay switching state, select to stop the test or collect the current disturbance energy and ripple ratio of the vehicle under test, and determine whether to perform secondary operating condition identification on the vehicle under test by combining the current disturbance energy and ripple ratio.

2. The test process control method for an on-board power test bench based on self-identification of working conditions as described in claim 1, characterized in that: In step S1, the current circuit signal of the vehicle under test is collected by a current sensor arranged in the output circuit of the vehicle power test bench. The current loop signal is a sampling sequence of actual current values ​​that change over time. Its physical meaning is the magnitude of the instantaneous conduction current in the loop during the process of the on-board power test bench supplying power to the vehicle under test. Within the preset sampling period, the vehicle-mounted power test bench continuously samples the current loop signal at the preset sampling period.

3. The test process control method for an on-board power test bench based on self-identification of working conditions according to claim 2, characterized in that: In step S1, when the amplitude of the current loop signal remains at zero within a preset sampling period, it indicates that the loop of the vehicle under test has not been established and the vehicle under test is in an unpowered state. When the current loop signal remains non-zero for at least one consecutive sampling period and does not fall back to zero in the next sampling period, the current loop signal is determined to have a continuous characteristic. When the current loop signal simultaneously switches from zero to non-zero and does not exhibit continuous characteristics in subsequent continuous sampling periods, the vehicle under test is determined to be in a powered-on state and enters the operating condition identification mechanism. Conversely, maintain the current monitoring status and do not enter the operating condition identification mechanism.

4. The test process control method for an on-board power test bench based on self-identification of working conditions according to claim 1, characterized in that: In step S2, after entering the working condition identification mechanism, an identification period for working condition determination is set, and the bus current data and AC ripple data of the vehicle under test are synchronously detected within the identification period. Bus current data reflects the actual conduction current on the bus during the process of the on-board power test bench supplying power to the vehicle under test; The AC ripple data is the amplitude of the AC component superimposed on the bus voltage, which is acquired by a ripple sampling sensor located on the bus output circuit side.

5. The test process control method for an on-board power test bench based on self-identification of working conditions according to claim 4, characterized in that: In step S2, a bus current data sequence is constructed in chronological order from the bus current data obtained by continuous sampling within the identification period; Based on the constructed bus current data sequence, the change in bus current between adjacent sampling points is calculated to obtain the bus current change rate. The voltage ramp-up coefficient is calculated by statistically processing the rate of change of current of each bus during the identification period. When the voltage ramp-up coefficient is less than or equal to the preset ramp-up judgment threshold, the bus voltage is judged to be in a slow build-up state, and the corresponding vehicle under test is in a pre-charging state. When the voltage ramp-up coefficient is greater than the preset ramp-up judgment threshold, it is determined that the bus voltage establishment process does not meet the pre-charging characteristics, and the vehicle under test is not in the pre-charging condition.

6. The test process control method for an on-board power test bench based on self-identification of working conditions according to claim 1, characterized in that: In step S3, when the vehicle under test is in the pre-charging condition, the AC ripple data are arranged in chronological order, and the difference between adjacent AC ripple data is calculated and the absolute value is taken to obtain the ripple difference value. The difference between the maximum and minimum values ​​of the ripple difference is used to obtain the ripple amplitude expansion, and the ratio of the ripple amplitude expansion to the recognition period is used as the ripple mutation index. A preset sampling period is used to detect the high-voltage bus current through a Hall current sensor within the preset sampling period. The high-voltage bus currents are arranged in chronological order, and the absolute value of the difference between adjacent high-voltage bus currents is used to obtain the current change amplitude.

7. The test process control method for an on-board power test bench based on self-identification of working conditions as described in claim 6, characterized in that: In step S3, the vehicle test record library is accessed to obtain samples of current change amplitude during the historical power-on process, including each historical current change amplitude, and the current change peak reference is calculated based on each historical current change amplitude. If the current change amplitude is greater than the current change peak reference, it is determined to be a current change peak event. Conversely, it is not considered a current change spike event; The number of current change spike events is used as the change spike count, and the ratio of the change spike count to the preset sampling period is used as the change spike characteristic. The product of the standardized change spike characteristics and the ripple mutation index is used as the switching joint index. If the switching joint index is greater than the preset switching joint threshold, the relay switching state is determined to be a relay switching occurrence state. Conversely, the relay switching state is determined to be a non-relay switching state.

8. The test process control method for an on-board power test bench based on self-identification of working conditions according to claim 7, characterized in that: In step S4, when the relay switching state is non-relay switching state, the current disturbance energy and ripple ratio of the vehicle under test are selected for acquisition. When the relay switching state is in the relay switching occurrence state, select Stop Test; When the relay switching state is non-relay switching state, a preset disturbance assessment period is set. Within the preset disturbance assessment period, the high-voltage bus current of the vehicle under test is continuously sampled, and the current change amplitude is calculated. The current disturbance energy is calculated based on the current change amplitude.

9. The test process control method for an on-board power test bench based on self-identification of working conditions as described in claim 8, characterized in that: In step S4, the AC ripple data detected during the disturbance assessment period are arranged in chronological order, and the difference between adjacent AC ripple data is used to obtain the AC ripple change amplitude. If the amplitude of the previous AC ripple change is less than the amplitude of the next AC ripple change, then the amplitude of the next AC ripple change is marked. Conversely, the amplitude of AC ripple variation is not marked; The amplitude of adjacent marker AC ripple changes is combined into an AC ripple duration sequence, and the ripple ratio is calculated based on the time length corresponding to the AC ripple duration sequence. The current disturbance energy and ripple ratio are standardized separately to obtain the current disturbance coefficient and ripple ratio coefficient. The total disturbance coefficient is obtained by summing the current disturbance coefficient and the ripple ratio coefficient.

10. The test process control method for an on-board power test bench based on self-identification of working conditions according to claim 9, characterized in that: In step S4, the current disturbance weight and ripple ratio weight are calculated using the total disturbance coefficient. The disturbance intensity characteristics are further obtained by weighting the current disturbance weight and the ripple ratio weight with the current disturbance coefficient and the ripple ratio coefficient, respectively. If the disturbance intensity characteristic is greater than the preset disturbance intensity threshold, it is determined that the vehicle under test will undergo secondary operating condition identification. Conversely, if the condition is not specified, it will be determined that the vehicle under test will not undergo secondary condition identification.

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