Vehicle fast charger circuit detection system and method

Abstract

The application relates to the technical field of vehicle-mounted fast-charging chargers, and particularly discloses a vehicle-mounted fast-charging charger circuit detection system and method, which comprises a signal acquisition module, a protocol analysis module used for being connected with a communication interface in a circuit, the protocol analysis module being used for synchronously analyzing communication protocol data between the circuit and external equipment, an electromagnetic compatibility detection module used for being connected with a power input end and a signal output end in the circuit, a chip detection module used for being connected with a chip in the circuit, a data analysis and processing module, and the signal acquisition module, the protocol analysis module, the electromagnetic compatibility detection module, the chip detection module and the data analysis and processing module are cooperatively matched, so that the vehicle-mounted fast-charging charger circuit can be comprehensively and deeply detected, basic performance parameters and a communication protocol can be detected, hidden faults in a chip and complex electromagnetic compatibility problems can be accurately found, and the detection accuracy and reliability are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vehicle-mounted fast-charging chargers, and particularly relates to a vehicle-mounted fast-charging charger circuit detection system and method. BACKGROUND

[0002] The vehicle-mounted fast-charging charger circuit is a vehicle-mounted charging device for electric vehicles or hybrid electric vehicles, which mainly shortens the charging time and improves user experience through fast charging technology. At present, the detection of the vehicle-mounted fast-charging charger circuit usually needs to use special automatic test equipment to perform comprehensive performance testing and fault detection.

[0003] For example, a detection device for a vehicle-mounted charger is disclosed in Chinese patent document application No. 201310522070.9. The detection device is connected to the vehicle-mounted charger through an electronic power meter and a PCAN by a BMS host computer. The low-voltage output end of the vehicle-mounted charger is connected to a low-voltage electronic load, and the high-voltage output end of the vehicle-mounted charger is connected to a high-voltage electronic load and an oscilloscope to simulate the CAN communication state of the real vehicle and transmit and receive instructions. The vehicle-mounted charger is comprehensively detected by the detection software on the BMS host computer and the oscilloscope. The advantages of the invention are as follows: 1. The vehicle-mounted charger can be conveniently and quickly detected comprehensively; 2. The cost of the electrical devices used is relatively low, which maximally reduces the production cost; and 3. The electronic load is used to replace the real vehicle, which is convenient and fast for detection.

[0004] However, the above detection device can perform comprehensive detection, but mainly focuses on the detection of the basic performance and communication of the charger circuit. For some complex and deep circuit faults, such as hidden faults in the chip and complex electromagnetic compatibility problems, accurate detection and positioning may not be possible, thereby affecting the accuracy of the detection. Therefore, we need to propose a vehicle-mounted fast-charging charger circuit detection system and method to solve the above problems, so that the vehicle-mounted fast-charging charger circuit can be comprehensively and deeply detected, and the accuracy and reliability of the detection are improved. SUMMARY

[0005] The purpose of the present application is to provide a vehicle-mounted fast-charging charger circuit detection system and method, which can comprehensively and deeply detect the vehicle-mounted fast-charging charger circuit, not only detect basic performance parameters and communication protocols, but also accurately find hidden faults in the chip and complex electromagnetic compatibility problems, thereby improving the accuracy and reliability of the detection to solve the problems proposed in the above background.

[0006] To achieve the above purpose, the present application adopts the following technical solutions:

[0007] The vehicle fast charger circuit detection system includes: a signal acquisition module, which acquires basic electrical signals of voltage, current and frequency in the circuit in real time through a sensor group;

[0008] A protocol parsing module connected to the communication interface in the circuit, the protocol parsing module being used to synchronously parse the communication protocol data between the circuit and external devices;

[0009] An electromagnetic compatibility (EMC) testing module is connected to the power input terminal and signal output terminal of the circuit. The EMC testing module is used to perform EMI testing and EMS testing on the circuit respectively.

[0010] A chip testing module connected to a chip in a circuit, the chip testing module being used to perform functional testing and electrical characteristic testing on the chip in the circuit;

[0011] The data analysis and processing module receives all data from each module and performs comprehensive analysis and processing to identify potential faults and abnormalities in the circuit. Based on the identification results, it generates a diagnostic report and provides fault information and maintenance suggestions.

[0012] The data analysis and processing module is electrically connected to the signal acquisition module, protocol parsing module, electromagnetic compatibility detection module, and chip detection module, respectively.

[0013] Preferably, the signal acquisition module includes a sensor group and a signal conditioning unit. The sensor group includes a voltage sensor, a current sensor, and a frequency counter, and the voltage sensor, current sensor, and frequency counter are all connected to the signal conditioning unit.

[0014] Preferably, the protocol parsing module includes a signal receiving unit, a signal decoding unit, and a protocol verification unit. The signal receiving unit is electrically connected to the signal decoding unit, and the signal decoding unit is electrically connected to the protocol verification unit. The signal receiving unit receives communication signals between the vehicle fast charger and external devices through a communication interface circuit.

[0015] Preferably, the process by which the signal decoding unit synchronously parses the communication protocol data is as follows:

[0016] A1. According to the data frame format specified in the fast charging protocol, find the start bit, end bit, frame header and frame tail markers in the signal, and divide the continuous signal into data frames.

[0017] A2. Extract the instruction code, data format, and transmission rate information from the data frame according to the field order and length specified in the protocol;

[0018] A3. Use a decoding algorithm to convert the extracted information into raw binary data.

[0019] Preferably, the protocol verification unit performs the following process to detect whether there are errors or anomalies:

[0020] B1. Check whether the format of the decoded data frame conforms to the protocol standard. The data frame format includes the order, length and value range of the fields.

[0021] B2. According to the checksum algorithm specified in the protocol, certain fields in the data frame are calculated to obtain the calculated checksum value. Then, the calculated checksum value is compared with the checksum value carried in the data frame. If the checksum value is not equal to the checksum value carried in the data frame, it indicates that an error has occurred in the data transmission process.

[0022] B3. Construct a state machine based on the state transition diagram of the fast charging protocol. Based on the received instructions and data, determine whether the current protocol is transitioning as expected. If the state transition does not conform to the protocol, it indicates that there is a protocol anomaly.

[0023] Preferably, the electromagnetic compatibility testing module includes an EMI testing unit for measuring electromagnetic radiation and conducted interference signals generated when the vehicle fast charger circuit is working, and an EMS testing unit for evaluating the anti-interference capability of the vehicle fast charger circuit. Both the EMI testing unit and the EMS testing unit are connected to the data analysis and processing module.

[0024] Preferably, the procedure for measuring electromagnetic radiation and conducted interference signals by the EMI detection unit is as follows:

[0025] C1. Place the vehicle fast charger in an electromagnetic shielding room and use a near-field probe to collect electromagnetic radiation signals from various parts of the vehicle fast charger circuit.

[0026] C2. Connect a conducted interference measuring device to the power line of the vehicle fast charger circuit to measure the electromagnetic interference signal transmitted from the vehicle fast charger circuit to the power grid through the power line.

[0027] C3. Perform frequency domain signal conversion on the collected electromagnetic radiation and electromagnetic interference signals. The frequency domain signal conversion formula is as follows:

[0028] k = 0, 1, ..., N-1, where X(k) is the k-th component of the frequency domain signal, x(m) is the m-th sampling point of the time domain signal, N is the number of sampling points, k is the frequency domain index used to represent different frequency points, k takes values ​​from 0 to N-1, m is the time domain index used to traverse all sampling points, and j is the imaginary unit;

[0029] C4. Compare the electromagnetic radiation intensity or conducted interference intensity at different frequency points with the limits specified in the relevant standards to determine whether they meet the standards. If the electromagnetic radiation intensity or conducted interference intensity at that frequency point meets the standards, then there is no electromagnetic interference problem in the vehicle fast charger circuit. If the electromagnetic radiation intensity or conducted interference signal at that frequency point does not meet the standards, then there is an electromagnetic interference problem in the vehicle fast charger circuit.

[0030] Preferably, the chip detection module includes a boundary scanning unit for functional testing of the internal logic circuits of the chip and a chip detection unit for electrical characteristic testing of the chip, both of which are connected to the data analysis and processing module.

[0031] Preferably, the data analysis and processing module performs comprehensive analysis and processing through an embedded processor, and the analysis and processing flow is as follows:

[0032] H1. Convert the data output from different modules into a unified format;

[0033] H2. Extract features from each module based on the transformed data;

[0034] H3. Compare the extracted data features with the features in the normal mode to confirm whether there is a potential fault. If there is no potential fault, repeat steps H1-H3; if there is a potential fault, determine the fault location and proceed to H4.

[0035] H4. After identifying potential faults, use a location algorithm to determine the location of the fault;

[0036] H5. Generate a detailed diagnostic report based on the analysis results and provide maintenance recommendations; the diagnostic report includes information on the type of fault, the location of the fault, and the severity assessment of the fault.

[0037] Based on the on-board fast charger circuit testing system described above, this invention also provides an on-board fast charger circuit testing method, comprising the following steps:

[0038] S1. Connect the vehicle fast charger circuit to the signal acquisition module, protocol parsing module, electromagnetic compatibility testing module, and chip testing module;

[0039] S2. Start the vehicle fast charger circuit to start charging, and initialize the signal acquisition module, protocol parsing module, electromagnetic compatibility detection module and chip detection module to ensure that each module can work normally.

[0040] S3. The signal acquisition module collects the basic parameter electrical signals of voltage, current and frequency in the vehicle fast charger circuit in real time, and transmits the basic parameter electrical signals to the data analysis and processing module.

[0041] S4. Synchronously parse the communication protocol data between the vehicle fast charger circuit and external devices through the protocol parsing module, and transmit the parsed protocol data to the data analysis and processing module.

[0042] S5. Perform EMI and EMS tests on the vehicle fast charger circuit through the electromagnetic compatibility testing module to obtain the electromagnetic radiation and conducted interference capabilities and anti-interference capabilities of the vehicle fast charger circuit, and transmit the test results to the data analysis and processing module.

[0043] S6. The chip detection module performs functional and electrical characteristic tests on the chip in the vehicle fast charger circuit and transmits the chip-related data to the data analysis and processing module.

[0044] S7. The data analysis and processing module performs comprehensive analysis and processing on all received data, identifies potential faults and abnormalities in the on-board fast charger circuit, generates a diagnostic report based on the identification results, and provides fault information and maintenance suggestions.

[0045] The on-board fast charger circuit detection system and method proposed in this invention have the following advantages compared with the prior art:

[0046] 1. This invention, through the coordinated operation of a signal acquisition module, a protocol parsing module, an electromagnetic compatibility detection module, a chip detection module, and a data analysis and processing module, can perform comprehensive and in-depth testing of the circuit of an on-board fast charger. It can not only detect basic performance parameters and communication protocols, but also accurately detect hidden faults inside the chip and complex electromagnetic compatibility issues, thereby improving the accuracy and reliability of the testing.

[0047] 2. This invention comprehensively analyzes and processes the basic parameters of the vehicle fast charger circuit, the communication protocol data between the vehicle fast charger circuit and external devices, the electromagnetic radiation and conducted interference signals generated by the vehicle fast charger circuit, the anti-interference capability, and the chip-related data. This enables comprehensive and accurate detection of the vehicle fast charger circuit, timely detection of various potential faults and problems, improved fault detection accuracy and efficiency, and reduced errors and missed detections in manual testing. Attached Figure Description

[0048] Figure 1 A system block diagram of a detection system according to an embodiment of the present invention is shown;

[0049] Figure 2 A flowchart illustrating the synchronous parsing of communication protocol data by a signal decoding unit according to an embodiment of the present invention is shown.

[0050] Figure 3A flowchart illustrating the measurement of electromagnetic radiation and conducted interference signals by an EMI detection unit according to an embodiment of the present invention is shown.

[0051] Figure 4 A flowchart of the data analysis and processing module according to an embodiment of the present invention is shown, which performs comprehensive analysis and processing through an embedded processor.

[0052] Figure 5 A flowchart of a circuit detection method according to an embodiment of the present invention is shown. Detailed Implementation

[0053] 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. The specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention. 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.

[0054] This invention provides, for example Figures 1-4 The vehicle fast charger circuit testing system shown includes a signal acquisition module, a protocol parsing module for connecting to the communication interface in the vehicle fast charger circuit, an electromagnetic compatibility testing module for connecting to the power input terminal and signal output terminal in the vehicle fast charger circuit, a chip testing module for connecting to the chip in the vehicle fast charger circuit, and a data analysis and processing module. The data analysis and processing module is electrically connected to the signal acquisition module, the protocol parsing module, the electromagnetic compatibility testing module, and the chip testing module, respectively.

[0055] The signal acquisition module collects basic parameter electrical signals of voltage, current and frequency in the on-board fast charger circuit in real time through the sensor group, and transmits the basic parameter electrical signals to the data analysis and processing module. The voltage and current signals output by the signal acquisition module are analog signal sampling data, and the frequency signal is digital counting data.

[0056] The signal acquisition module includes a sensor group and a signal conditioning unit. The sensor group includes a voltage sensor, a current sensor, and a frequency counter. The voltage sensor, current sensor, and frequency counter are all connected to the signal conditioning unit. The voltage and current sensors acquire voltage and current signals in the circuit, and the frequency counter acquires frequency signals. The signal conditioning unit then amplifies and filters the signals output by the sensor group to improve signal quality. The processed signal is then transmitted to the data analysis and processing module.

[0057] The protocol parsing module is used to synchronously parse the communication protocol data between the vehicle fast charger circuit and the external device, and transmit the parsed protocol data to the data analysis and processing module. The character instruction data output by the protocol parsing module is the parsed communication protocol instruction, such as charging instruction, data transmission instruction, etc.

[0058] The protocol parsing module includes a signal receiving unit, a signal decoding unit, and a protocol verification unit. The signal receiving unit is electrically connected to the signal decoding unit, and the signal decoding unit is electrically connected to the protocol verification unit. The signal receiving unit receives communication signals between the vehicle fast charger and external devices through a communication interface circuit. The signal decoding unit decodes the received signals according to the standard specifications of the fast charging protocol, extracting information such as instruction codes, data formats, and transmission rates. The protocol verification unit compares the decoded information with the protocol standard to determine the correctness and integrity of the protocol and detect any errors or anomalies. The protocol verification unit mainly detects errors or anomalies in the communication protocol itself, such as data frame format errors, checksum errors, and abnormal protocol state transitions.

[0059] The signal receiving unit is connected to the communication lines of the vehicle fast charger and external devices via a USB or CAN communication interface. The operating mode and baud rate parameters of the interface circuit are set to match the format of the communication signal. Then, the receiving program is started to continuously monitor the signal on the communication line.

[0060] The process by which the signal decoding unit synchronously parses the communication protocol data is as follows:

[0061] A1. According to the data frame format specified in the fast charging protocol, find the start bit, end bit, frame header and frame tail markers in the signal, and divide the continuous signal into data frames.

[0062] A2. Extract the instruction code, data format, and transmission rate information from the data frame according to the field order and length specified in the protocol;

[0063] A3. Use a decoding algorithm to convert the extracted information back into original binary data. The formula for the decoding algorithm is:

[0064] If V(0.5T)-V(0)>0, then the bit is 0; if V(0.5T)-V(0)<0, then the bit is 1, where V(0) is the level at the beginning of the bit period, T is the bit period, and V(0.5T) is the level at the middle of the bit period.

[0065] The protocol verification unit performs the following process to detect whether there are errors or anomalies:

[0066] B1. Check whether the format of the decoded data frame conforms to the protocol standard. The data frame format includes the order, length and value range of the fields.

[0067] B2. According to the checksum algorithm specified in the protocol, certain fields in the data frame are calculated to obtain a checksum value. This checksum value is then compared with the checksum value carried in the data frame. If the checksum value is not equal to the checksum value carried in the data frame, it indicates that an error occurred during data transmission. The formula for the checksum algorithm is:

[0068] Where C is the checksum, d i This represents the i-th byte in the data, where n is the total number of bytes in the data;

[0069] The checksum value is calculated by applying a protocol-defined algorithm to specified fields in the data frame. It is used to verify the correctness of data transmission. The checksum value carried in the data frame is calculated by the sender during frame construction, according to protocol requirements (such as fast charging protocols). Key fields (such as instruction codes and data content) are selected, and a pre-defined checksum algorithm (such as cumulative summation or CRC cyclic redundancy check) is used to calculate the checksum. This value is then added to a specific location in the data frame (such as the frame trailer) as a basis for data integrity verification.

[0070] B3. Construct a state machine based on the state transition diagram of the fast charging protocol. Based on the received instructions and data, determine whether the current protocol is transitioning as expected. If the state transition does not conform to the protocol, it indicates that there is a protocol anomaly.

[0071] A state machine is a mathematical model used to describe the state transition process of a protocol under different input conditions. A state machine consists of a set of states, a set of inputs, a state transition function, and an output function. Based on the state transition diagram of the fast charging protocol, various states of the protocol (such as standby state, handshake state, charging state, etc.) and the transition conditions and transition methods between states are defined. This state machine is used to monitor whether the execution of the protocol meets expectations.

[0072] The electromagnetic compatibility testing module performs EMI and EMS tests on the vehicle fast charger circuit to obtain the electromagnetic radiation and conducted interference capabilities and anti-interference capabilities of the vehicle fast charger circuit, and transmits the test results to the data analysis and processing module.

[0073] The electromagnetic compatibility (EMC) testing module includes an EMI testing unit for measuring electromagnetic radiation and conducted interference signals generated during the operation of the vehicle fast charger circuit, and an EMS testing unit for evaluating the anti-interference capability of the vehicle fast charger circuit. Both the EMI and EMS testing units are connected to the data analysis and processing module. The EMI testing unit outputs electromagnetic radiation intensity data in dBμV / m, conducted interference voltage data in dBμV, and conducted interference current data in dBμA. The EMS testing unit outputs anti-interference capability test results including the charger's operating status and performance indicators under different interference intensities. The chip testing module outputs chip pin resistance data in Ω, capacitance data in F, and leakage current data in A. It also includes chip test commands and corresponding response data. The EMI and EMS testing units mainly detect EMC-related issues, such as excessive electromagnetic radiation and insufficient anti-interference capability.

[0074] The procedure for measuring electromagnetic radiation and conducted interference signals by the EMI detection unit is as follows:

[0075] C1. Place the vehicle fast charger in an electromagnetic shielding room and use a near-field probe to collect electromagnetic radiation signals from various parts of the vehicle fast charger circuit. The near-field probe is placed at key parts of the vehicle charger's input / output interface, power conversion module, and control circuit board according to the actual electromagnetic radiation collection requirements, which can effectively locate the electromagnetic radiation source.

[0076] C2. Connect a conducted interference measuring device to the power line of the vehicle fast charger circuit to measure the electromagnetic interference signal transmitted from the vehicle fast charger circuit to the power grid through the power line.

[0077] C3. Perform frequency domain signal conversion on the collected electromagnetic radiation and electromagnetic interference signals. The frequency domain signal conversion formula is as follows:

[0078] k = 0, 1, ..., N-1, where X(k) is the k-th component of the frequency domain signal, x(m) is the m-th sampling point of the time domain signal, N is the number of sampling points, k is the frequency domain index used to represent different frequency points, k takes values ​​from 0 to N-1, m is the time domain index used to traverse all sampling points, j is the imaginary unit, and e is the base of the natural logarithm used to convert the time domain signal x(m) to the frequency domain representation X(k);

[0079] C4. Compare the electromagnetic radiation intensity or conducted interference intensity at different frequency points with the limits specified in the relevant standards to determine whether they meet the standards. If the electromagnetic radiation intensity or conducted interference intensity at that frequency point meets the standards, that is, the measured electromagnetic radiation intensity or conducted interference intensity is less than or equal to the standard electromagnetic radiation intensity or conducted interference intensity value, then there is no electromagnetic interference problem in the vehicle fast charger circuit. If the electromagnetic radiation intensity or conducted interference signal at that frequency point does not meet the standards, that is, the measured electromagnetic radiation intensity or conducted interference intensity is greater than the standard electromagnetic radiation intensity or conducted interference intensity value, then there is an electromagnetic interference problem in the vehicle fast charger circuit. The relevant standards are set as CISPR or RN series standards.

[0080] The process for the EMS detection unit to perform anti-interference capability testing is as follows:

[0081] D1. Use an electromagnetic interference generator to generate electromagnetic interference signals of different types and intensities.

[0082] The formula for generating electromagnetic interference signals using an electromagnetic interference generator is as follows:

[0083] Where V(k) is a voltage signal that varies with time, V g ω is the peak voltage of the signal, i.e., the maximum voltage value the signal can reach, which determines the strength of the interference signal; ω is the angular frequency used to determine the signal's frequency characteristics; and t is the time taken for the signal to change. To determine the initial phase of the signal at the initial moment;

[0084] D2. Apply the generated electromagnetic interference signal to the vehicle fast charger using a discharge gun. When applying the electromagnetic interference signal, it is necessary to operate in accordance with the relevant regulations in terms of method and location to ensure the consistency and reliability of the interference.

[0085] D3. When electromagnetic interference signals are applied, use an oscilloscope and logic analyzer to monitor the output and control signals of the vehicle fast charger in real time.

[0086] D4. Evaluate the anti-interference capability of the vehicle fast charger based on the monitoring results. If the vehicle fast charger can maintain normal operation under the specified interference intensity and all performance indicators are within the allowable range, the charger is considered to have passed the EMS test. Otherwise, if performance degradation, malfunction or failure occurs, the cause needs to be further analyzed and corresponding improvement measures should be taken, such as optimizing circuit design and strengthening electromagnetic shielding. Then, the test should be carried out again until the charger meets the requirements.

[0087] The chip detection module performs functional and electrical characteristic tests on the chips in the vehicle fast charger circuit and transmits the chip-related data to the data analysis and processing module.

[0088] The chip testing module includes a boundary scanning unit for testing the internal logic circuit functions of the chip and a chip detection unit for testing the electrical characteristics of the chip. Both the boundary scanning unit and the chip detection unit are connected to the data analysis and processing module.

[0089] The procedure for functional testing of the internal logic circuits of the chip by the boundary scan unit is as follows:

[0090] E1. Connect the JTAG controller to the chip's JTAG interface, initialize the communication link, and ensure that signals can be transmitted correctly between the JTAG controller and the chip.

[0091] E2, the JTAG controller sends control commands to the chip for testing internal logic circuits and pin states according to the format and timing specified by the JTAG protocol, and uses the control commands to control the boundary scan unit inside the chip to perform different types of tests.

[0092] E3. The boundary scan unit performs corresponding operations based on the received control commands, and the test results are returned to the JTAG controller through the JTAG interface.

[0093] The E4 and JTAG controllers read the data scanned by the boundary scan unit and compare the read data with the pre-set expected results. By checking the consistency of the data, it can be determined whether the internal logic circuit of the chip is working properly. If a data mismatch is found, it means that the chip has a logic error, short circuit, or open circuit problem. The pre-set expected results are set according to industry testing standards and specifications. During boundary scan testing, according to the standard, for a specific test instruction sequence, the chip should return data in a specific format and content. This data specified by the standard is the expected result.

[0094] The process for testing the electrical characteristics of the chip by the chip detection unit is as follows;

[0095] F1. Place the chip on the probe stage, ensuring that the probe is accurately aligned with and in contact with the chip's pins to establish an electrical connection between the probe and the chip's pins.

[0096] F2. Using the electrical connection provided by the probe station, apply test signals from an external signal source to the chip pins. The test signals include voltage signals and current signals.

[0097] F3. While applying the test signal, measure the resistance value of each pin and compare the measured resistance value with the standard value in the chip's datasheet. If the measured resistance value exceeds the normal range of the standard value, it is determined that there is an abnormality in the chip's electrical performance. That is, if the resistance value is infinite, the chip has an open circuit at the pin; if the resistance value is close to 0, the chip has a short circuit. If the measured resistance value is within the normal range of the standard value, it is determined that there is no abnormality in the chip's electrical performance.

[0098] The data analysis and processing module performs comprehensive analysis and processing on all received data, identifies potential faults and abnormalities in the on-board fast charger circuit, generates a diagnostic report based on the identification results, and provides fault information and maintenance suggestions.

[0099] The data analysis and processing module performs comprehensive analysis and processing through an embedded processor. The analysis and processing flow is as follows:

[0100] H1. Convert the data output from different modules into a unified format; specifically: for the analog signal sampling data (voltage, current) of the signal acquisition module, convert it from its original binary format to floating-point format. The conversion formula is: floating-point number = binary value × resolution + offset, where the resolution and offset are determined according to the sensor's range; the digital counting data of the frequency signal is directly converted to floating-point format.

[0101] For character-type instruction data output by the protocol parsing module, convert it into ASCII encoding format for storage;

[0102] For the electromagnetic radiation intensity data (dBμV / m), conducted interference voltage data (dBμV), and conducted interference current data (dBμA) output by the electromagnetic compatibility testing module, the dB values ​​are first converted to actual physical quantities based on the sensor's range and resolution (e.g., electromagnetic radiation intensity is converted from dBμV / m to μV / m). The conversion formula is: physical quantity value = 10^(dB value / 20). A timestamp is added to each detection data (format: YYYY-MM-DDHH:MM:SS.ms). Then, the converted electromagnetic radiation intensity and conducted interference data are organized into a structured data format containing information such as timestamp, physical quantity value, and detection location.

[0103] For the electrical parameter data such as chip pin resistance (Ω), capacitance (F), and leakage current (A) obtained by the chip detection module, the data is converted according to the range and resolution of the measuring instrument (e.g., converting the ADC sample value to the actual resistance value, the conversion formula is: resistance value = reference resistance × (2^n - sample value) / sample value, where n is the number of bits of the ADC and the reference resistance is a known standard resistance). The electrical parameter data of each pin is labeled (e.g., "chip U1 pin 1 resistance") to indicate the chip to which the pin belongs and the pin number. At the same time, the chip test command and the corresponding response data are associated and organized into a structured data format containing information such as command, response and test time.

[0104] H2. Based on the converted data, feature extraction is performed on each module. The specific operation of feature extraction is as follows: For the data of the signal acquisition module, the voltage and current signals in the time domain are converted into frequency domain signals using the Fast Fourier Transform (FFT) algorithm, and their frequency features (such as fundamental frequency, harmonic frequency and their amplitude) are extracted. The FFT algorithm can obtain the spectrum distribution of the signal and analyze whether there are abnormal frequency components. For frequency signals, their numerical features (such as frequency value, frequency stability, etc.) are directly extracted and compared with the frequency range during normal operation to determine whether there are frequency anomalies.

[0105] For the data in the protocol parsing module, key information in the communication protocol is extracted by parsing specific fields of the protocol data packets, such as the version number of the charging protocol and the charging power negotiation value as features.

[0106] For the data from the electromagnetic compatibility testing module, the mean and variance of electromagnetic radiation intensity are calculated to statistically identify characteristics, as well as the threshold of electromagnetic susceptibility.

[0107] The chip detection module performs bitwise operations on the chip register data to obtain the values ​​of specific function bits, thereby determining whether the chip's operating mode is normal.

[0108] H3. Compare the extracted data features with the features in the normal mode to confirm whether there is a potential fault. If there is no potential fault, repeat steps H1-H3; if there is a potential fault, determine the fault location and proceed to H4.

[0109] Specifically: for the voltage data characteristics of the signal acquisition module, if it exceeds the threshold of the normal operating voltage range, an overvoltage fault may be identified; for the charging power negotiation value of the protocol parsing module, if it does not match the power value specified in the charger specification and exceeds the allowable error range, a charging protocol fault may be identified; for the average electromagnetic radiation intensity of the electromagnetic compatibility detection module, if it exceeds the limit specified by the relevant standard, an electromagnetic radiation exceeding the standard fault may be identified; for the error codes of the chip detection module, if a specific error code appears, it indicates that the chip may have a certain type of fault, such as a communication fault or a logic error.

[0110] H4. After identifying potential faults, the location algorithm is used to determine the fault's location. Specifically: for faults in the signal acquisition module, the location algorithm determines the specific location of the fault point in the charger circuit through the sensor's number or location information; for faults in the protocol parsing module, the location algorithm determines which communication interface or protocol processing unit is malfunctioning through communication link state matrix analysis; the formula for the communication link state matrix is:

[0111] Where h is the total number of horizontal nodes in the communication link, c is the total number of vertical nodes in the communication link, and M is the communication link state matrix. ch When M = 1, it indicates that communication between node c and node h is normal. ch When = 0, it indicates that the communication between node c and node h is abnormal;

[0112] For faults in the electromagnetic compatibility (EMC) detection module, the fault location algorithm is based on the electromagnetic radiation gradient. The gradient along the x-direction in space is calculated, and the fault source location is determined by finding the point of maximum value. The calculation formula is as follows:

[0113]

[0114]

[0115]

[0116] in, and Let Δx, Δy, and Δz be the gradient components of the electromagnetic radiation intensity in the x, y, and z directions, respectively; I(x,y,z) is the electromagnetic radiation intensity measured at coordinates (x,y,z); and Δx, Δy, and Δz are the small displacement increments in the x, y, and z directions, respectively.

[0117] For faults in the chip detection module, the fault location algorithm is based on logic gate circuit fault analysis. The logic gate circuit output formula is:

[0118] Where Y is the logic gate output, l is the number of logic gate inputs, and X... b Let X be the b-th input variable of the logic gate. b When X = 1, the logic gate works normally, indicating no fault. b When the value is 0, the logic gate cannot work, indicating a fault.

[0119] H5. Generate a detailed diagnostic report based on the analysis results and provide maintenance recommendations; the diagnostic report includes information on the type of fault, the location of the fault, and the severity assessment of the fault.

[0120] The repair recommendations include: for faulty chips, it is recommended to replace them with specific models; for issues with excessive electromagnetic radiation, it is recommended to take shielding measures or replace them with components that have better electromagnetic compatibility; the repair recommendations should be actionable so that repair personnel can carry out effective repairs and adjustments based on the report.

[0121] The data analysis and processing module compares the extracted data features with those in normal mode, performing comprehensive fault detection and potential fault identification at the overall system level. It not only includes fault types detected by each module individually, but also identifies anomalies in the relationships between modules and some hidden potential faults that require comprehensive data analysis for diagnosis. The specific correlation methods are as follows:

[0122] Protocol errors or abnormal data detected by the protocol parsing module will be transmitted to the data analysis and processing module as output data. When performing feature extraction, the data analysis and processing module will compare these protocol-related features (such as protocol version number, charging power negotiation value, etc.) with the features in normal mode. If the protocol parsing module has determined that there is a protocol error or abnormality, the data analysis and processing module will further analyze the impact of the abnormality on the operation of the entire system and whether there are other related faults.

[0123] Data indicating excessive electromagnetic radiation or insufficient anti-interference capability detected by the electromagnetic compatibility (EMC) detection module will be transmitted as output data to the data analysis and processing module. During feature extraction, the data analysis and processing module will compare the statistical characteristics of the mean and variance of electromagnetic radiation intensity, as well as the characteristics of the electromagnetic sensitivity threshold, with the characteristics in normal mode. If the EMC detection module has determined that there is an electromagnetic interference problem, the data analysis and processing module will combine data from other modules (such as voltage and current data from the signal acquisition module, chip operating status data from the chip detection module, etc.) to comprehensively analyze the impact of the electromagnetic interference problem on other parts of the circuit, and whether there are other potential faults caused by electromagnetic interference.

[0124] In addition to the faults detected individually by each module, the data analysis and processing module can also discover potential faults that cannot be detected by individual modules by comprehensively analyzing the data characteristics of each module. For example, when the voltage and current data of the signal acquisition module fluctuate abnormally, but the protocol parsing module and the electromagnetic compatibility detection module do not detect obvious abnormalities, the data analysis and processing module may discover potential faults such as component aging and poor contact in the circuit by comparing these data characteristics with those in normal mode.

[0125] The data analysis and processing module can quickly locate the fault based on the data provided by each module and provide detailed diagnostic results, helping maintenance personnel to repair the fault in a timely and accurate manner, reducing troubleshooting time and maintenance costs.

[0126] Through the coordinated operation of the signal acquisition module, protocol parsing module, electromagnetic compatibility testing module, chip testing module, and data analysis and processing module, a comprehensive and in-depth test of the vehicle fast charger circuit can be performed. It can not only test basic performance parameters and communication protocols, but also accurately detect hidden faults inside the chip and complex electromagnetic compatibility issues, thus improving the accuracy and reliability of the test.

[0127] Based on the on-board fast charger circuit testing system described above, this invention also provides an on-board fast charger circuit testing method, such as... Figure 5 As shown, it includes the following steps:

[0128] S1. Connect the vehicle fast charger circuit to the signal acquisition module, protocol parsing module, electromagnetic compatibility testing module, and chip testing module;

[0129] S2. Start the vehicle fast charger circuit to start charging, and initialize the signal acquisition module, protocol parsing module, electromagnetic compatibility detection module and chip detection module to ensure that each module can work normally.

[0130] S3. The signal acquisition module collects the basic parameter electrical signals of voltage, current and frequency in the vehicle fast charger circuit in real time, and transmits the basic parameter electrical signals to the data analysis and processing module.

[0131] S4. Synchronously parse the communication protocol data between the vehicle fast charger circuit and external devices through the protocol parsing module, and transmit the parsed protocol data to the data analysis and processing module.

[0132] S5. Perform EMI and EMS tests on the vehicle fast charger circuit through the electromagnetic compatibility testing module to obtain the electromagnetic radiation and conducted interference capabilities and anti-interference capabilities of the vehicle fast charger circuit, and transmit the test results to the data analysis and processing module.

[0133] S6. The chip detection module performs functional and electrical characteristic tests on the chip in the vehicle fast charger circuit and transmits the chip-related data to the data analysis and processing module.

[0134] S7. The data analysis and processing module performs comprehensive analysis and processing on all received data, identifies potential faults and abnormalities in the on-board fast charger circuit, generates a diagnostic report based on the identification results, and provides fault information and maintenance suggestions.

[0135] By comprehensively analyzing and processing the basic parameters of the vehicle fast charger circuit, the communication protocol data between the vehicle fast charger circuit and external devices, the electromagnetic radiation and conducted interference signals generated by the vehicle fast charger circuit, the anti-interference capability, and the chip-related data, it is possible to achieve comprehensive and accurate testing of the vehicle fast charger circuit, timely detect various potential faults and problems, improve the accuracy and efficiency of fault detection, and reduce the errors and missed detections of manual testing.

[0136] It should be noted that the vehicle fast charger circuit used in this invention is a well-known technology in the field. For example, Chinese patent application number 202021333432.1 discloses a fast charging vehicle charger circuit, including capacitor C1, capacitor C2, step-down chip U1 of model IP6520, inductor L1, capacitor C3, capacitor C4 and output port (20). The positive terminal of capacitor C1 is connected to one end of the car battery (10), one end of capacitor C2 and pin 2 of step-down chip U1. The negative terminal of capacitor C1 is connected to the other end of the car battery (10), the other end of capacitor C2, and the ground terminal. One end of inductor L1 is connected to one end of capacitor C3, pin 3 of step-down chip U1, and the ground terminal. The other end of capacitor C3 is connected to pin 4 of step-down chip U1. The other end of inductor L1 is connected to pin 1 of step-down chip U1, the positive terminal of capacitor C4, and the input terminal of output port (20). The negative terminal of capacitor C4 is connected to the ground terminal and the input terminal of output port (20).

[0137] The modules in the vehicle fast charger circuit detection system of the present invention are connected to the fast charging vehicle charger circuit as follows: one end of the voltage sensor is connected to the line connecting the positive terminal of capacitor C1 and the car battery 10, and is used to collect the input DC voltage signal; the other end is connected to the line connecting pin 1 of step-down chip U1, inductor L1, capacitor C4 and output port 20, and is used to collect the output DC voltage signal.

[0138] A current sensor is connected in series in the line connecting the car battery 10 and the positive terminal of the capacitor C1 to collect the charging input current; or it is connected in series in the line connecting the inductor L1 and the output port 20 to collect the output charging current.

[0139] If the fast-charging vehicle charger has a dedicated communication interface (such as a CAN interface or USB interface) for communicating with external devices, the protocol parsing module connects to that communication interface through the corresponding interface circuit. For example, if it is a CAN interface, the CAN transceiver of the protocol parsing module is connected to the CAN interface pin of the vehicle charger to receive and send fast-charging protocol signals transmitted on the CAN bus.

[0140] EMI Detection Unit: The near-field probe can move around the charger circuit board, close to components such as capacitors C1, C2, C3, C4, inductor L1, and step-down chip U1, to collect the electromagnetic radiation signals generated by these components during operation. The conducted interference measurement device is connected in series on the power line connecting the car battery 10 and the charger, and is used to measure the electromagnetic interference signals transmitted by the charger to the power grid through the power line.

[0141] EMS testing unit: The charger is placed in the test area of ​​the electromagnetic compatibility test system. The interference signal generated by the electromagnetic interference generator is applied to the power line (the line connected to the car battery 10) and signal line (if there is a communication signal line, etc.) of the charger through the coupling device, while monitoring the working status and output signal of the charger.

[0142] Boundary Scan Technology (JTAG): Connects to the buck converter chip U1 via a JTAG interface. The pins of the JTAG interface are connected to the corresponding JTAG pins on the buck converter chip U1, typically including test data input (TDI), test data output (TDO), test clock (TCK), and test mode selection (TMS) pins, enabling communication with the internal boundary scan unit of the chip for chip testing.

[0143] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vehicle-mounted fast charger circuit detection system, characterized in that: include: The signal acquisition module acquires basic electrical signals of voltage, current and frequency in the circuit in real time through a sensor group. A protocol parsing module connected to the communication interface in the circuit, the protocol parsing module being used to synchronously parse the communication protocol data between the circuit and external devices; The protocol parsing module includes a signal receiving unit, a signal decoding unit, and a protocol verification unit. The signal receiving unit is electrically connected to the signal decoding unit, and the signal decoding unit is electrically connected to the protocol verification unit. The signal receiving unit receives communication signals between the vehicle fast charger and external devices through a communication interface circuit. The protocol verification unit performs the following process to detect whether there are errors or anomalies: B1. Check whether the format of the decoded data frame conforms to the protocol standard. The data frame format includes the order, length and value range of the fields. B2. According to the checksum algorithm specified in the protocol, certain fields in the data frame are calculated to obtain the calculated checksum value. Then, the calculated checksum value is compared with the checksum value carried in the data frame. If the checksum value is not equal to the checksum value carried in the data frame, it indicates that an error has occurred in the data transmission process. B3. Construct a state machine based on the state transition diagram of the fast charging protocol. Based on the received instructions and data, determine whether the current protocol is transitioning as expected. If the state transition does not conform to the protocol specifications, it indicates that there is a protocol anomaly. An electromagnetic compatibility (EMC) testing module is connected to the power input terminal and signal output terminal of the circuit. The EMC testing module is used to perform EMI testing and EMS testing on the circuit respectively. A chip testing module connected to a chip in a circuit, the chip testing module being used to perform functional testing and electrical characteristic testing on the chip in the circuit; The data analysis and processing module receives all data from each module and performs comprehensive analysis and processing to identify potential faults and abnormalities in the circuit. Based on the identification results, it generates a diagnostic report and provides fault information and maintenance suggestions. The data analysis and processing module is electrically connected to the signal acquisition module, protocol parsing module, electromagnetic compatibility detection module, and chip detection module, respectively.

2. The vehicle-mounted fast charger circuit detection system according to claim 1, characterized in that: The signal acquisition module includes a sensor group and a signal conditioning unit. The sensor group includes a voltage sensor, a current sensor, and a frequency counter. The voltage sensor, current sensor, and frequency counter are all connected to the signal conditioning unit.

3. The on-board fast charger circuit detection system according to claim 2, characterized in that: The process by which the signal decoding unit synchronously parses the communication protocol data is as follows: A1. According to the data frame format specified in the fast charging protocol, find the start bit, end bit, frame header and frame tail markers in the signal, and divide the continuous signal into data frames. A2. Extract the instruction code, data format, and transmission rate information from the data frame according to the field order and length specified in the protocol; A3. Use a decoding algorithm to convert the extracted information into raw binary data.

4. The on-board fast charger circuit detection system according to claim 1, characterized in that: The electromagnetic compatibility testing module includes an EMI testing unit for measuring electromagnetic radiation and conducted interference signals generated when the vehicle fast charger circuit is working, and an EMS testing unit for evaluating the anti-interference capability of the vehicle fast charger circuit. Both the EMI testing unit and the EMS testing unit are connected to the data analysis and processing module.

5. The on-board fast charger circuit detection system according to claim 4, characterized in that: The procedure for measuring electromagnetic radiation and conducted interference signals by the EMI detection unit is as follows: C1. Place the vehicle fast charger in an electromagnetic shielding room and use a near-field probe to collect electromagnetic radiation signals from various parts of the vehicle fast charger circuit. C2. Connect a conducted interference measuring device to the power line of the vehicle fast charger circuit to measure the electromagnetic interference signal transmitted from the vehicle fast charger circuit to the power grid through the power line. C3. Perform frequency domain signal conversion on the collected electromagnetic radiation and electromagnetic interference signals. The frequency domain signal conversion formula is as follows: ， in, The first frequency domain signal One portion, The first time domain signal There are N sampling points, where N is the number of sampling points. This is a frequency domain index used to represent different frequency points. The value ranges from 0 to N-1. This is a time-domain index used to traverse all sampling points. The imaginary unit; C4. Compare the electromagnetic radiation intensity or conducted interference intensity at different frequency points with the limits specified in the relevant standards to determine whether they meet the standards. If the electromagnetic radiation intensity or conducted interference intensity at that frequency point meets the standards, then there is no electromagnetic interference problem in the vehicle fast charger circuit. If the electromagnetic radiation intensity or conducted interference signal at that frequency point does not meet the standards, then there is an electromagnetic interference problem in the vehicle fast charger circuit.

6. The on-board fast charger circuit detection system according to claim 5, characterized in that: The chip testing module includes a boundary scanning unit for testing the internal logic circuit functions of the chip and a chip detection unit for testing the electrical characteristics of the chip. Both the boundary scanning unit and the chip detection unit are connected to the data analysis and processing module.

7. The on-board fast charger circuit detection system according to claim 6, characterized in that: The data analysis and processing module performs comprehensive analysis and processing through an embedded processor. The analysis and processing flow is as follows: H1. Convert the data output from different modules into a unified format; H2. Extract features from each module based on the transformed data; H3. Compare the extracted data features with the features in the normal mode to confirm whether there is a potential fault. If there is no potential fault, repeat steps H1-H3; if there is a potential fault, determine the fault location and proceed to H4. H4. After identifying potential faults, use a location algorithm to determine the location of the fault; H5. Generate a detailed diagnostic report based on the analysis results and provide maintenance recommendations; the diagnostic report includes information on the type of fault, the location of the fault, and the severity assessment of the fault.

8. A method for testing the circuit of an on-board fast charger, based on the on-board fast charger circuit testing system according to any one of claims 1-7, characterized in that: Includes the following steps: S1. Connect the vehicle fast charger circuit to the signal acquisition module, protocol parsing module, electromagnetic compatibility testing module, and chip testing module; S2. Start the vehicle fast charger circuit to start charging, and initialize the signal acquisition module, protocol parsing module, electromagnetic compatibility detection module and chip detection module to ensure that each module can work normally. S3. The signal acquisition module collects the basic parameter electrical signals of voltage, current and frequency in the vehicle fast charger circuit in real time, and transmits the basic parameter electrical signals to the data analysis and processing module. S4. Synchronously parse the communication protocol data between the vehicle fast charger circuit and external devices through the protocol parsing module, and transmit the parsed protocol data to the data analysis and processing module. S5. Perform EMI and EMS tests on the vehicle fast charger circuit through the electromagnetic compatibility testing module to obtain the electromagnetic radiation and conducted interference capabilities and anti-interference capabilities of the vehicle fast charger circuit, and transmit the test results to the data analysis and processing module. S6. The chip detection module performs functional and electrical characteristic tests on the chip in the vehicle fast charger circuit and transmits the chip-related data to the data analysis and processing module. S7. The data analysis and processing module performs comprehensive analysis and processing on all received data, identifies potential faults and abnormalities in the on-board fast charger circuit, generates a diagnostic report based on the identification results, and provides fault information and maintenance suggestions.

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