Output current sampling and evaluation system for dual-shaft low-voltage motor drivers

Abstract

This invention discloses an output current sampling and evaluation system for a dual-axis low-voltage motor driver, comprising modules for single-resistor signal acquisition, common-mode interference suppression, dual-axis current separation, current parameter extraction, sampling accuracy evaluation, and evaluation result integration. The system acquires the bus current signal through a single resistor. The common-mode interference suppression module filters out interference based on an equivalent common-mode circuit model. The dual-axis current separation module then separates the dual-axis current signal according to the single-resistor bus current sampling model. After extracting characteristic parameters, the system generates accuracy data through sampling accuracy evaluation and finally integrates the results into a comprehensive evaluation report. This system solves the problems of insufficient dual-axis coupling processing and systematic deficiencies in common-mode interference evaluation in traditional evaluation methods, improving the accuracy and comprehensiveness of dual-axis current sampling evaluation.

Description

Technical Field

[0001] This invention relates to the field of dual-axis low-voltage motor drivers, and more particularly to an output current sampling and evaluation system for dual-axis low-voltage motor drivers. Background Technology

[0002] With the rapid development of industrial automation, robotics, and precision transmission systems, dual-axis low-voltage motor drives are widely used in small robotic arms, precision CNC machine tools, and intelligent warehousing equipment due to their ability to achieve multi-dimensional collaborative control. These drives require real-time and accurate acquisition of the dual-axis output current to ensure motor operation stability and control precision. Single-resistor bus current sampling has become the mainstream choice due to its low cost and simple structure. However, the complex electromagnetic environment during dual-axis motor operation, interference from switching states, and the dual-axis current coupling effect pose challenges to the accuracy of output current sampling, necessitating the development of a dedicated evaluation system to verify the reliability of the sampled data.

[0003] Existing technologies have significant shortcomings in the sampling and evaluation of output current for dual-axis low-voltage motor drivers. On the one hand, traditional evaluation methods are mostly designed for single-axis motors and do not fully consider the coupling relationship of dual-axis currents in a single-resistor sampling circuit. This makes it difficult to accurately separate and evaluate the true characteristics of the currents in each axis, leading to deviations between the evaluation results and actual operating conditions. On the other hand, the suppression and evaluation of common-mode interference lack a systematic approach, relying solely on simple filtering circuits without combining equivalent common-mode circuit models to analyze the sources and extent of interference. This fails to quantify the specific impact of common-mode interference on the sampling accuracy of dual-axis currents, thus affecting the accuracy of the overall driver performance evaluation. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the present invention provides an output current sampling and evaluation system for a dual-axis low-voltage motor driver.

[0005] The technical solution adopted in this invention is an output current sampling and evaluation system for a dual-axis low-voltage motor driver, comprising:

[0006] A single-resistor signal acquisition module acquires the raw current signal through a single sampling resistor set on the bus of a dual-axis low-voltage motor driver. The raw current signal includes bus current fluctuation information during the operation of the dual-axis motor. The signal output terminal of this module is connected to the signal input terminal of a common-mode interference suppression module.

[0007] The common-mode interference suppression module receives the raw current signal output by the single-resistor signal acquisition module, constructs a common-mode signal path suppression structure based on the equivalent common-mode circuit model, and filters out the common-mode interference components included in the raw current signal. The signal output terminal of this module is connected to the signal input terminal of the dual-axis current separation module.

[0008] The dual-axis current separation module receives the interference-reducing current signal output by the common-mode interference suppression module. Based on the mapping relationship between the phase current of the dual-axis motor and the bus current in the single-resistor bus current sampling model, the interference-reducing current signal is separated into the A-axis current signal and B-axis current signal of the corresponding dual-axis motor by analyzing the current conduction path under different switching states. The signal output terminal of this module is connected to the signal input terminal of the current parameter extraction module.

[0009] The current parameter extraction module receives the A-axis current signal and B-axis current signal output by the dual-axis current separation module, performs time-domain feature analysis on the A-axis current signal and B-axis current signal, and extracts feature parameters including current peak value, current effective value, current ripple coefficient, current rise slope and current fall slope. The signal output terminal of this module is connected to the signal input terminal of the sampling accuracy evaluation module.

[0010] The sampling accuracy evaluation module receives various characteristic parameters output by the current parameter extraction module, combines them with the preset standard parameter range of the output current of the dual-axis motor driver, and generates A-axis current sampling accuracy data and B-axis current sampling accuracy data by comparing the degree of deviation between the characteristic parameters and the standard parameters. The signal output terminal of this module is connected to the signal input terminal of the evaluation result integration module.

[0011] The evaluation result integration module receives the A-axis current sampling accuracy data and B-axis current sampling accuracy data output by the sampling accuracy evaluation module. According to the axis priority sorting rules of the dual-axis motor driver, the module integrates the A-axis current sampling accuracy data and B-axis current sampling accuracy data into a comprehensive evaluation report that includes a dual-axis current sampling deviation comparison table, sampling accuracy level classification, and calibration sampling point error distribution.

[0012] Furthermore, the common-mode interference suppression module, based on the equivalent common-mode circuit model, constructs a common-mode signal path suppression structure that satisfies the following formula:

[0013] ;

[0014] in, Indicates the equivalent common-mode capacitance; This represents the parasitic capacitance between the single-resistance signal acquisition module and the A-axis motor power module; This represents the parasitic capacitance between the single-resistance signal acquisition module and the B-axis motor power module; This represents the stray capacitance between the sampling circuit and the motor housing;

[0015] Meanwhile, the module's suppression of common-mode interference satisfies the following:

[0016] ;

[0017] in, Indicates the common-mode rejection ratio; Indicates the common-mode interference input voltage; Indicates the common-mode interference output voltage; Indicates the angular frequency of the common-mode interference signal; This represents the suppression resistor in a common-mode rejection circuit; This represents a differential capacitor.

[0018] Furthermore, in the single-resistance bus current sampling model upon which the dual-axis current separation module is based, the mapping relationship between the phase current of the dual-axis motor and the bus current satisfies the following formula:

[0019] ;

[0020] in, This represents the bus current at time t; This represents the A-axis current mapping coefficient, the value of which is determined by the ratio of the on-state voltage drop of the A-axis motor power transistor to the resistance value of the sampling resistor; This represents the A-axis motor phase current at time t; This represents the switching duty cycle of the A-axis motor power module at time t, with a value ranging from 0 to 1. This represents the B-axis current mapping coefficient, the value of which is determined by the ratio of the on-state voltage drop of the B-axis motor power transistor to the resistance value of the sampling resistor. This represents the B-axis motor phase current at time t; This represents the duty cycle of the B-axis motor power module at time t, with a value ranging from 0 to 1.

[0021] The formula is obtained through analysis. shaft current signal and The separation expression for the shaft current signal is:

[0022] .

[0023] Furthermore, the current ripple coefficient extracted by the current parameter extraction module satisfies the following formula:

[0024] ;

[0025] in, Indicates the current ripple factor; Indicates the peak value of the current signal; Represents the valley value of the current signal; This represents the effective value of the current signal;

[0026] Meanwhile, the current rising edge slope and current falling edge slope extracted by this module satisfy the following:

[0027] ;

[0028] in, Indicates the slope of the current rising edge; This indicates that the peak value is reached on the rising edge. The current value; This indicates the current value that reaches 10% of the peak value during the rising edge; This indicates that the peak value is reached on the rising edge. The moment This indicates that the peak value is reached on the rising edge. The moment; Indicates the slope of the falling edge of the current; Indicates the drop to the peak value at the middle of the falling edge. The moment; Indicates the drop to the peak value at the middle of the falling edge. At that moment.

[0029] Furthermore, the A-axis current sampling accuracy data and B-axis current sampling accuracy data generated by the sampling accuracy evaluation module satisfy the following formula:

[0030] ;

[0031] in, This indicates the overall error of the A-axis current sampling; This indicates the measured peak value of the A-axis current; This indicates the standard value of the peak A-axis current; This represents the measured effective value of the A-axis current. This indicates the standard value of the effective value of the A-axis current; This represents the measured value of the A-axis current ripple coefficient; This represents the standard value of the A-axis current ripple factor; This indicates the overall error of the B-axis current sampling; This indicates the measured peak value of the B-axis current. This indicates the standard value of the B-axis current peak. This represents the measured effective value of the B-axis current. This indicates the standard value of the effective value of the B-axis current; This represents the measured value of the B-axis current ripple coefficient; This represents the standard value of the B-axis current ripple coefficient.

[0032] Furthermore, when the evaluation result integration module integrates the comprehensive evaluation report, the deviation quantification value of the biaxial current sampling deviation comparison table satisfies the following formula:

[0033] ;

[0034] in, This represents the percentage of relative deviation between the current sampling of the A-axis and B-axis at time t. This indicates the overall error of the A-axis current sampling; This represents the A-axis motor phase current at time t; This indicates the overall error of the B-axis current sampling; This represents the B-axis motor phase current at time t;

[0035] Meanwhile, the classification of sampling accuracy levels is based on the following formula:

[0036] ;

[0037] Here, Grade represents the sampling accuracy level, with levels 1 to 4 corresponding to high accuracy, medium-high accuracy, medium accuracy, and low accuracy, respectively.

[0038] Furthermore, the biaxial current separation module includes:

[0039] The switching state analysis unit receives the interference-reducing current signal output by the common-mode interference suppression module and synchronously acquires the switching state signals of the A-axis power module and the B-axis power module in the dual-axis motor driver. The switching state signals include the on / off indicators of the upper and lower bridge arm switches of each phase. By performing timing analysis on the switching state signals, the switching state combination in each PWM cycle is determined.

[0040] The current path mapping unit receives the switch state combination output by the switch state analysis unit. Based on the current flow rules under different switch states in the single resistor bus current sampling model, it establishes the correspondence between the switch state combination and the conduction paths of the A-axis current and B-axis current, and clarifies the contribution ratio of the bus current to the A-axis current and B-axis current under different states.

[0041] The separation algorithm execution unit receives the contribution ratio output by the current path mapping unit and the de-interference current signal output by the common-mode interference suppression module. Based on the preset dual-axis current separation algorithm, the de-interference current signal is decomposed into independent A-axis current signal and B-axis current signal according to the contribution ratio. The decomposition process must meet the current conservation constraint under different switching states.

[0042] The separation result verification unit receives the A-axis current signal and B-axis current signal output by the separation algorithm execution unit. By comparing the deviation value between the algebraic sum of the A-axis current signal and the B-axis current signal in the same PWM cycle and the de-interference current signal, if the deviation value exceeds the preset threshold, the separation algorithm execution unit is triggered to re-perform the current separation process.

[0043] Furthermore, the current parameter extraction module includes:

[0044] The time-domain feature detection unit receives the A-axis current signal and B-axis current signal output by the dual-axis current separation module, performs point-by-point scanning on the A-axis current signal and B-axis current signal, identifies the peak point, valley point, rising edge start point, rising edge end point, falling edge start point and falling edge end point in the signal waveform, and records the current value and timestamp corresponding to each feature point.

[0045] The effective value calculation unit receives the current signal waveform data output by the time domain feature detection unit, and performs integration on the square values ​​of the A-axis current signal and the B-axis current signal within a preset time window according to the definition of the effective value of current. Then, the integration result is divided by the length of the time window and the square root is taken to obtain the effective value of the A-axis current and the effective value of the B-axis current.

[0046] The ripple coefficient analysis unit receives the peak and valley current values ​​output by the time-domain feature detection unit, as well as the effective current value output by the effective value calculation unit. Based on the difference between the peak and valley values ​​and the ratio of the effective current value, the A-axis current ripple coefficient and the B-axis current ripple coefficient are calculated.

[0047] The slope calculation unit receives the current values ​​and timestamps of the rising and falling edge feature points output by the time-domain feature detection unit. It obtains the current rising edge slope by calculating the ratio of the current change from 10% peak value to 90% peak value in the rising edge to the corresponding time change, and obtains the current falling edge slope by calculating the ratio of the current change from 90% peak value to 10% peak value in the falling edge to the corresponding time change.

[0048] Furthermore, the sampling accuracy evaluation module includes:

[0049] The standard parameter storage unit stores the standard parameters of the output current of the dual-axis motor driver under different operating conditions. The standard parameters include the rated peak current, rated effective current, maximum allowable ripple coefficient, standard rise slope range, and standard fall slope range of the A-axis and B-axis. The standard parameters are updated through an external interface.

[0050] The feature parameter comparison unit receives the A-axis and B-axis feature parameters output by the current parameter extraction module and the corresponding standard parameters output by the standard parameter storage unit. It calculates the difference between the current peak value, current effective value, current ripple coefficient, current rise slope and current fall slope one by one to obtain the absolute deviation value of each parameter.

[0051] The deviation quantization unit receives the absolute deviation values ​​output by the feature parameter comparison unit, takes the ratio of the absolute deviation value to the corresponding standard parameter as the relative deviation value, and then integrates the relative deviation values ​​into the A-axis current sampling comprehensive deviation and the B-axis current sampling comprehensive deviation by weighted summation.

[0052] The accuracy level determination unit receives the comprehensive deviation of A-axis current sampling and the comprehensive deviation of B-axis current sampling from the deviation quantization unit, determines the sampling accuracy level of A-axis and B-axis respectively with reference to the preset accuracy level classification threshold, and generates accuracy evaluation data including accuracy level identifier and deviation out-of-tolerance items.

[0053] Beneficial Effects: This invention proposes an output current sampling and evaluation system for dual-axis low-voltage motor drivers. This system achieves comprehensive and accurate evaluation of the output current sampling of dual-axis low-voltage motor drivers by constructing a complete module chain including single-resistor signal acquisition, common-mode interference suppression, dual-axis current separation, current parameter extraction, sampling accuracy evaluation, and evaluation result integration. Its beneficial effects are reflected in the following aspects: Specifically designed for dual-axis motors, it analyzes the dual-axis current coupling relationship using a single-resistor bus current sampling model and accurately extracts the current characteristics of each axis through a dual-axis current separation module, overcoming the shortcomings of traditional single-axis evaluation methods in handling dual-axis coupling; it introduces an equivalent common-mode circuit model to construct a common-mode interference suppression structure, and combines this with a sampling accuracy evaluation module to quantify the impact of interference on sampling accuracy, replacing simple filtering and solving the problem of a lack of systematic approach in common-mode interference evaluation. Simultaneously, through multi-dimensional parameter extraction and comprehensive evaluation, it provides a reliable basis for driver performance optimization, significantly improving the accuracy and practicality of dual-axis current sampling evaluation. Attached Figure Description

[0054] Figure 1 This is a diagram showing the system module composition of the present invention;

[0055] Figure 2 This is a flowchart of the system operation of the present invention. Detailed Implementation

[0056] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] like Figure 1 As shown, an output current sampling and evaluation system for a dual-shaft low-voltage motor driver includes:

[0058] A single-resistor signal acquisition module acquires the raw current signal through a single sampling resistor set on the bus of a dual-axis low-voltage motor driver. The raw current signal includes bus current fluctuation information during the operation of the dual-axis motor. The signal output terminal of this module is connected to the signal input terminal of a common-mode interference suppression module.

[0059] Specifically, the single-resistor signal acquisition module is the fundamental component of the entire system for obtaining raw current information. Its core function is to capture the bus current signal generated during the operation of the dual-axis low-voltage motor by using a single sampling resistor located on the bus of the dual-axis low-voltage motor driver. The performance of this module directly affects the accuracy of all subsequent processing stages. The selection of the sampling resistor value is crucial, typically determined based on the rated current range of the driver, generally between 0.01 ohms and 0.1 ohms. This range ensures a sufficiently large voltage signal for acquisition at the rated current while avoiding increased power loss due to excessive resistance. Simultaneously, to adapt to the operating environment of the low-voltage motor driver, the sampling resistor must have a low temperature coefficient, typically controlled below 50 ppm / ℃, to reduce the impact of ambient temperature changes on sampling accuracy. Furthermore, the module's signal output must employ a differential output method to initially suppress common-mode interference, and the output signal bandwidth should be no less than 1 MHz to ensure complete capture of current fluctuations generated by high-frequency switching actions.

[0060] In the specific implementation process, firstly, a suitable sampling resistor is selected based on the rated operating current of the dual-axis low-voltage motor driver (e.g., a rated current of 5A). If the driver's maximum operating current is 10A, a 0.05-ohm precision alloy resistor with a power rating of 5W can be selected. This resistor has an accuracy of 0.1%, which meets the basic requirements for sampling accuracy. The sampling resistor is connected in series with the DC bus of the driver, ensuring good contact at the connection point between the resistor and the bus. The contact resistance is controlled below 1 milliohm to avoid introducing additional measurement errors due to contact resistance. The signal conditioning circuit inside the module amplifies the voltage signal across the sampling resistor. The amplification factor is set according to the actual situation. For example, when the bus current is 10A, the voltage across the sampling resistor is 0.5V. The voltage signal is amplified to 5V by an operational amplifier with a magnification factor of 10 to match the input range of the subsequent analog-to-digital conversion circuit (usually 0-5V). At the same time, an RC filter network is set in the conditioning circuit, with a capacitor value of 10nF and a resistor value of 1k ohm, forming a low-pass filter with a cutoff frequency of approximately 16kHz to filter out high-frequency noise. After conditioning, the signal is transmitted to the signal input of the common-mode interference suppression module via a differential transmission line (length controlled within 10cm). Twisted-pair cable is used in the transmission line to reduce the impact of electromagnetic radiation. The module's power supply design employs a ±15V precision regulated power supply with power ripple controlled within 1mV to ensure stable operation of the conditioning circuit. The entire module operates within a temperature range of -40℃ to 85℃ to adapt to various industrial environments.

[0061] The common-mode interference suppression module receives the raw current signal output by the single-resistor signal acquisition module, constructs a common-mode signal path suppression structure based on the equivalent common-mode circuit model, and filters out the common-mode interference components included in the raw current signal. Its signal output terminal is connected to the signal input terminal of the dual-axis current separation module.

[0062] Specifically, the common-mode interference suppression module is a key component in improving the system's anti-interference capability. Its main function is to eliminate or reduce common-mode interference components contained in the original current signal. These interferences mainly originate from the high-frequency switching action of the power switching transistors in the motor driver, electromagnetic radiation from the motor windings, and electromagnetic noise in the external environment. Common-mode interference can cause a shift in the sampled signal, affecting the accuracy of subsequent current separation and parameter extraction. Therefore, the performance of this module is crucial to the overall system evaluation accuracy. The module is designed based on an equivalent common-mode circuit model and can specifically suppress common-mode interference within a specific frequency range. The common-mode rejection ratio (CMRR) is an important indicator of the module's performance; in the frequency range of 100Hz to 1MHz, the CMRR should be no less than 80dB. In addition, the insertion loss of this module should be less than 0.5dB to avoid excessive attenuation of the useful signal, and the input impedance of the module should be no less than 100k ohms to reduce the impact on the preceding single-resistor signal acquisition module.

[0063] In practical implementation, the module employs a three-stage common-mode interference suppression measure. The first stage is a common-mode choke, using a nanocrystalline core material with an inductance of 10mH and a rated current of 20A. This effectively suppresses high-frequency common-mode interference, covering an operating frequency range of 1kHz to 100MHz. The common-mode choke is connected in series in the signal transmission path, with the turns ratio of the two windings strictly controlled at 1:1, with an error not exceeding 0.1%, to ensure minimal impact on differential-mode signals. The second stage is an active common-mode rejection circuit, using a dedicated instrumentation amplifier (such as the AD8221) as the core component. This amplifier achieves a common-mode rejection ratio of up to 140dB at DC and maintains above 120dB at 1kHz. By appropriately setting the external resistor of the amplifier, the gain is adjusted to 1x to maintain a constant signal amplitude. The feedback network in the circuit uses high-precision resistors (0.1% accuracy) and low-temperature drift capacitors (temperature coefficient 20ppm / ℃) to ensure the stability of circuit performance. The third stage is the shielding layer driver circuit, which keeps the shielding layer of the signal transmission line consistent with the common-mode voltage, reducing capacitive coupling between the shielding layer and the signal line. The output impedance of the shielding layer driver circuit is controlled below 10 ohms, and the response time is less than 100ns. In the module's grounding design, a single-point grounding method is adopted, with a grounding resistance of less than 1 ohm, avoiding interference introduced by ground loops. The entire module operates at ±12V, with an operating current of less than 5mA. Within a temperature range of -40℃ to 85℃, the change in the common-mode rejection ratio does not exceed 5dB, ensuring stable operation in various environments.

[0064] The dual-axis current separation module receives the de-interference current signal output by the common-mode interference suppression module. Based on the mapping relationship between the phase current of the dual-axis motor and the bus current in the single-resistor bus current sampling model, the de-interference current signal is separated into the A-axis current signal and B-axis current signal of the corresponding dual-axis motor by analyzing the current conduction path under different switching states. Its signal output terminal is connected to the signal input terminal of the current parameter extraction module.

[0065] Specifically, the dual-axis current separation module is the core component for achieving independent evaluation of dual-axis current. Its function is to separate the interference-reduced current signal (after common-mode interference suppression) into corresponding current signals for the A-axis and B-axis motors according to certain rules. Since the dual-axis motors share a single bus sampling resistor, the bus current may be the A-axis current, the B-axis current, or a combination of both, under different switching states. Therefore, accurate separation of the dual-axis current is required based on the switching state information of the motor driver. The separation accuracy of this module directly affects the accuracy of subsequent parameter extraction and accuracy evaluation; the separation error should be controlled within 1%. The module needs to receive the driver's switching state signal (such as the IGBT's on / off signal) in real time and synchronize it with the current signal, with a synchronization error not exceeding 100ns. Furthermore, the module's processing speed should meet the driver's switching frequency requirements; when the switching frequency is 20kHz, the module's processing cycle should not exceed 50μs.

[0066] In the specific implementation process, the switching status signals of the dual-axis motor driver are first received via a high-speed optocoupler (such as 6N137). The optocoupler's response time is less than 50ns, ensuring rapid capture of changes in the switching status. The switching status signals include the on / off information of six switching transistors in the upper and lower bridge arms of the A and B axes. These signals are then input to the Field Programmable Gate Array (FPGA) inside the module after level conversion. The FPGA uses the Xilinx Spartan-6 series with a clock frequency of 100MHz, enabling real-time processing of the switching status signals. Simultaneously, the interference-reducing current signal is converted into a digital signal via an analog-to-digital converter (ADC). The ADC uses a 16-bit precision chip with a sampling rate of 1MSPS (such as ADS8344), with a conversion error of less than ±1LSB. The sampling time is synchronized with the switching status signals via the FPGA, and the synchronization error is controlled within 50ns. The FPGA internally employs a separation algorithm based on a single-resistor bus current sampling model. The algorithm first determines the current conduction path based on the switch states. For example, when the upper bridge arm of the A-axis is on and the lower bridge arm is off, and the upper bridge arm of the B-axis is off and the lower bridge arm is on, the bus current equals the difference between the A-axis and B-axis currents. Then, based on different switch state combinations, the corresponding current separation formula is applied to separate the bus current digital signal into A-axis and B-axis current digital signals. To improve separation accuracy, compensation for the on-state voltage drop of the switching transistors is incorporated into the algorithm. Based on the current switch state and current magnitude, a pre-stored on-state voltage drop compensation table (obtained through experimental measurements; for example, when the current is 5A, the IGBT's on-state voltage drop is 1.2V) is consulted to correct the separation result. The separated A-axis and B-axis current signals are transmitted to the current parameter extraction module via an internal bus at a transmission rate of 10Mbps to ensure real-time data updates. The module is also equipped with a self-test function. When an abnormal switch status signal is detected (such as the upper and lower switches of the same bridge arm being turned on at the same time), a fault signal is immediately issued, and the separation result of the previous cycle is used as a temporary substitute to prevent erroneous data from entering the subsequent stages.

[0067] The current parameter extraction module receives the A-axis current signal and B-axis current signal output by the dual-axis current separation module, performs time-domain feature analysis on the A-axis current signal and B-axis current signal, and extracts feature parameters including current peak value, current effective value, current ripple coefficient, current rise slope and current fall slope. Its signal output terminal is connected to the signal input terminal of the sampling accuracy evaluation module.

[0068] Specifically, the main task of the current parameter extraction module is to extract various characteristic parameters reflecting the current characteristics from the separated A-axis and B-axis current signals. These parameters are the basis for evaluating sampling accuracy and include peak current, RMS current, current ripple coefficient, current rise slope, and current fall slope. Accurate extraction of these parameters requires the module to have high-precision signal analysis capabilities, able to identify key feature points in the current waveform and perform precise calculations. This module has high requirements for signal processing accuracy; for example, the measurement error of the peak current should not exceed 0.5%, and the calculation error of the RMS current should be controlled within 0.2%. Simultaneously, the module needs to have a fast processing speed; for the current signal of each axis, the parameter update cycle should not exceed 1ms to meet the needs of real-time evaluation. Furthermore, the module's input interface should have good compatibility, capable of receiving digital signals of different formats (such as parallel or serial data).

[0069] In practical implementation, the module receives A-axis and B-axis digital current signals (e.g., 16-bit parallel data) from the dual-axis current separation module. First, the digital signals are buffered in a dual-port RAM with a capacity of 4KB, capable of storing 1ms of data (1ms of data is 1000 points at a sampling rate of 1MSPS). The microprocessor (e.g., STM32H743) reads the data from the RAM for processing. First, the current signal is smoothed using a moving average filtering algorithm with a window size of 10 sampling points to eliminate the influence of high-frequency noise on feature point recognition. The distortion of the filtered signal waveform is controlled within 0.1%. For current peak extraction, the microprocessor compares the filtered current values ​​point by point, recording the maximum value within each cycle as the current peak. For example, in a 50Hz current signal, each cycle contains 20,000 sampling points (sampling rate 1MSPS). By comparison, the maximum value is found, achieving a measurement accuracy of 0.3%. The effective value of the current is calculated using the root mean square (RMS) algorithm. The square of the current over one period is integrated, divided by the period length, and the square root is taken. The integration uses the trapezoidal rule, resulting in a calculation error of less than 0.1%. For example, for a sinusoidal current signal, the calculated effective value deviates from the theoretical value by no more than 0.2%. The current ripple coefficient is obtained by calculating the difference between the peak and valley values ​​and then dividing by the effective value. The method for extracting valley values ​​is similar to that for peak values. To avoid misjudgment, a threshold is set; a valley value is only identified when five consecutive sampling points are all less than a certain value. The current rising edge slope is calculated by first determining the start point (when the current reaches 10% of the peak value) and the end point (when the current reaches 90% of the peak value) of the rising edge. The ratio of the current change to the time change between these two points is calculated. For example, if the current change from 10% peak value to 90% peak value is 4A and the time change is 20μs, then the slope is 200A / ms. The falling edge slope is calculated similarly, except that the start and end points are the 90% and 10% peak values ​​of the falling edge. The extracted parameters are stored in a data register and transmitted to the sampling accuracy evaluation module via an SPI interface (10Mbps). Each parameter is updated every 1ms to ensure real-time performance. The module also has a parameter calibration function, which uses an external standard signal source to input a current signal with known parameters to calibrate the extraction results. The calibration error can be controlled within 0.1%.

[0070] The sampling accuracy evaluation module receives various characteristic parameters output by the current parameter extraction module, combines them with the preset standard parameter range of the output current of the dual-axis motor driver, and generates A-axis current sampling accuracy data and B-axis current sampling accuracy data by comparing the degree of deviation between the characteristic parameters and the standard parameters. Its signal output terminal is connected to the signal input terminal of the evaluation result integration module.

[0071] Specifically, the sampling accuracy evaluation module is a crucial component for realizing the system's evaluation function. Its role is to compare the characteristic parameters obtained from the current parameter extraction module with preset standard parameters, quantifying and analyzing the degree of deviation in the sampled data, thereby generating sampling accuracy data for the A-axis and B-axis currents. The evaluation results of this module are the direct basis for judging the output current sampling performance of the dual-axis low-voltage motor driver; therefore, the objectivity and accuracy of the evaluation are paramount. The preset standard parameter range in the module should be determined based on the rated parameters and performance indicators of the dual-axis motor, covering parameter values ​​under different operating conditions (such as no-load, full-load, and different speeds). The evaluation method should be scientific, comprehensively reflecting the deviation of various parameters, and the output format of the evaluation results should be concise and clear, facilitating subsequent integration and processing. Furthermore, the module should have a standard parameter update function to adapt to the evaluation needs of motor drivers of different models or in different application scenarios.

[0072] In practical implementation, the module first stores the standard parameters of the dual-axis motor driver's output current under various operating conditions through an internal storage unit (such as EEPROM). For example, under rated speed (3000 rpm) and full load (5A) conditions, the standard peak current of the A-axis motor is 7A, the standard effective current is 5A, the standard current ripple coefficient is 0.15, the standard rise slope is 100A / ms, and the standard fall slope is 80A / ms. These standard parameters are pre-written by the host computer, and the storage accuracy is retained to three decimal places. The module receives the current parameters and extracts the characteristic parameters of the A-axis and B-axis output by the module. For example, the current peak current of the A-axis is 7.1A, the effective value is 5.05A, the ripple coefficient is 0.16, the rise slope is 95A / ms, and the fall slope is 78A / ms. The microprocessor (such as DSPTMS320F28335) compares each parameter one by one, calculating the absolute deviation and relative deviation. The absolute deviation is the difference between the measured value and the standard value (e.g., the peak absolute deviation is 0.1A), and the relative deviation is the ratio of the absolute deviation to the standard value (e.g., the peak relative deviation is 1.43%). For each relative deviation, the module calculates the overall deviation using a weighted summation method, where the peak current and RMS value have higher weights (30% each), the ripple coefficient accounts for 20%, and the rise and fall slopes each account for 10%. For example, the overall deviation of the A-axis is (1.43%×30%+1.00%×30%+6.67%×20%+5.00%×10%+2.50%×10%)=2.13%. The sampling accuracy level is determined based on the magnitude of the overall deviation, such as a comprehensive deviation less than 1% for Level 1 accuracy, 1%-3% for Level 2 accuracy, etc. Sampling accuracy data for both the A-axis and B-axis is generated, including the deviation values ​​of each parameter, the overall deviation value, and the accuracy level. This data is transmitted to the evaluation result integration module via an asynchronous serial communication interface (baud rate of 115200bps). During transmission, a checksum is used to ensure data integrity, with the checksum error rate controlled within 0.01%. The module also features a parameter over-limit alarm function. When the relative deviation of a parameter exceeds a preset threshold (e.g., 5%), an alarm signal is output to indicate that the parameter may be abnormal.

[0073] The evaluation result integration module receives the A-axis current sampling accuracy data and B-axis current sampling accuracy data output by the sampling accuracy evaluation module. According to the axis priority sorting rules of the dual-axis motor driver, the module integrates the A-axis current sampling accuracy data and B-axis current sampling accuracy data into a comprehensive evaluation report that includes a dual-axis current sampling deviation comparison table, sampling accuracy level classification, and calibration sampling point error distribution.

[0074] Specifically, the evaluation result integration module systematically integrates the A-axis and B-axis current sampling accuracy data output by the sampling accuracy evaluation module to form a comprehensive and intuitive integrated evaluation report, providing users with an overall assessment of the output current sampling performance of the dual-axis low-voltage motor driver. This module needs to organize and present the scattered accuracy data according to certain rules, highlighting key information to facilitate users' quick understanding of the sampling system's performance. The integrated report should include sufficient details, such as a comparison of dual-axis current sampling deviations, the sampling accuracy level of each axis, and the error distribution of key sampling points. Furthermore, the report format should be standardized for easy archiving and subsequent analysis. In addition, the module should have data storage capabilities, able to save evaluation reports for a certain period and support users in querying historical data.

[0075] In the specific implementation process, the module first receives the A-axis and B-axis sampling accuracy data transmitted by the sampling accuracy evaluation module. The data format includes timestamps, deviation values ​​of various parameters for each axis, overall deviation values, and accuracy levels. Data is received via a USB interface (USB 2.0 standard), with a transmission rate of up to 12Mbps, ensuring real-time data reception. The microcontroller inside the module (such as an ARM Cortex-A8) parses and classifies the received data, storing it in chronological order on an 8GB SD card, which can store approximately one year's worth of evaluation data (stored 24 hours a day, generating one report file per hour, each file approximately 100KB in size). According to the axis priority ranking rules of the dual-axis motor driver (e.g., the A-axis is the primary drive axis, with higher priority than the B-axis), the accuracy data of the A-axis and B-axis are sorted and compared to generate a dual-axis current sampling deviation comparison table. The table lists the relative deviation values ​​of each parameter, using different colors to indicate parameters with larger deviations (e.g., parameters with deviations exceeding 3% are displayed in red). Simultaneously, the overall sampling accuracy level of the dual axes is determined based on the overall deviation value and clearly marked in the report. For the error distribution of key sampling points (such as motor start-up time, load change time, etc.), the module presents it using statistical analysis tools (such as histograms). The statistical sample size is 100 sampling data points before and after each key sampling point. The mean, variance, and other statistical measures of the error are calculated to intuitively show the distribution range and central tendency of the error. The comprehensive evaluation report is generated in PDF format. Each page of the report includes time information, a dual-axis deviation comparison table, accuracy level classification results, and error distribution map of key sampling points. The report generation cycle can be set according to user needs (such as generating once per hour).

[0076] Preferably, the common-mode interference suppression module is based on a common-mode signal path suppression structure constructed using an equivalent common-mode circuit model, satisfying the following formula:

[0077] ;

[0078] in, This represents the equivalent common-mode capacitance, measured in farads (F). This represents the parasitic capacitance between the single-resistance signal acquisition module and the A-axis motor power module, measured in farads (F). This represents the parasitic capacitance between the single-resistance signal acquisition module and the B-axis motor power module, measured in farads (F). This represents the stray capacitance between the sampling circuit and the motor housing, measured in farads (F).

[0079] Meanwhile, the module's suppression of common-mode interference satisfies the following:

[0080] ;

[0081] in, This indicates the common-mode rejection ratio, expressed in decibels (dB). This represents the common-mode interference input voltage, measured in volts (V). This represents the common-mode interference output voltage, measured in volts (V). This represents the angular frequency of the common-mode interference signal, expressed in radians per second ( ). ); This represents the suppression resistor in a common-mode rejection circuit, with the unit being ohms (Ω). ); This represents differential capacitance, measured in farads (F).

[0082] Specifically, the common-mode interference suppression module constructs a common-mode signal path suppression structure based on an equivalent common-mode circuit model. Its core lies in effectively suppressing common-mode interference by accurately calculating the equivalent common-mode capacitance and the common-mode rejection ratio (CMRR). The calculation of the equivalent common-mode capacitance comprehensively considers the parasitic capacitance between the single-resistance signal acquisition module and the A-axis and B-axis motor power modules, as well as the stray capacitance between the sampling circuit and the motor housing. These capacitance parameters directly affect the coupling strength of common-mode interference. The size of the parasitic capacitance is usually related to the layout and packaging of the power module, while the stray capacitance is affected by the wiring method and housing material. By incorporating these capacitance parameters into the calculation, the propagation path characteristics of common-mode interference can be more accurately reflected. The calculation of the CMRR is related to parameters such as the common-mode interference input and output voltage, angular frequency, suppression resistor, and differential capacitor. The angular frequency reflects the frequency characteristics of the interference signal; different frequencies of interference have different degrees of impact on the system. The selection of the suppression resistor and differential capacitor needs to be matched according to the interference frequency range to ensure that the ideal suppression effect is achieved within the target frequency band. During implementation, it is necessary to first measure the specific values ​​of parasitic and stray capacitance using precision instruments. Impedance analyzers are typically used to measure at different frequency points to ensure data accuracy. Suppression resistors and differential capacitors are optimized and selected using simulation software. Appropriate parameter values ​​are determined based on the system's operating frequency range (e.g., 100Hz to 1MHz) to ensure a common-mode rejection ratio of no less than 80dB. Simultaneously, in terms of circuit layout, it is necessary to reduce the generation of parasitic capacitance, rationally plan the distance between the sampling loop and the power module, and adopt shielding measures to reduce the impact of stray capacitance. Ultimately, targeted suppression of common-mode interference is achieved, providing a stable and reliable signal foundation for subsequent current separation and parameter extraction.

[0083] Preferably, in the single-resistance bus current sampling model upon which the dual-axis current separation module is based, the mapping relationship between the phase current of the dual-axis motor and the bus current satisfies the following formula:

[0084] ;

[0085] in, The bus current at time t is expressed in amperes (A). This represents the A-axis current mapping coefficient, which is dimensionless and its value is determined by the ratio of the on-state voltage drop of the A-axis motor power transistor to the resistance value of the sampling resistor. The A-axis motor phase current at time t is expressed in amperes (A). This represents the switching duty cycle of the A-axis motor power module at time t. It is dimensionless and ranges from 0 to 1. This represents the B-axis current mapping coefficient, which is dimensionless and its value is determined by the ratio of the on-state voltage drop of the B-axis motor power transistor to the resistance value of the sampling resistor. The motor phase current of the B-axis at time t is expressed in amperes (A). This represents the duty cycle of the B-axis motor power module at time t. It is dimensionless and ranges from 0 to 1.

[0086] The formula is obtained through analysis. shaft current signal and The separation expression for the shaft current signal is:

[0087] .

[0088] Specifically, the core of the dual-axis current separation module is to establish a mapping relationship between the phase currents of the dual-axis motor and the bus current based on a single-resistor bus current sampling model, and to separate the current signals through this relationship. The construction of the mapping relationship needs to consider parameters such as the current mapping coefficients of the A-axis and B-axis, the phase currents, and the switching duty cycle of the power module. The current mapping coefficients are related to the on-state voltage drop of the power transistor and the resistance value of the sampling resistor. The on-state voltage drop of the power transistor varies with the current magnitude and temperature, requiring precise experimental measurement and compensation. The switching duty cycle reflects the operating state of the power module at different times and directly determines the coupling mode between the bus current and the dual-axis current. In the implementation process, firstly, the on-state voltage drop of the power transistor under different current and temperature conditions needs to be experimentally measured to establish a dynamic compensation table of mapping coefficients, ensuring the accuracy of the mapping coefficients under different operating conditions. Secondly, the switch duty cycle signal and bus current signal are synchronously acquired through a high-speed sampling circuit. The sampling frequency needs to be much higher than the switching frequency (e.g., when the switching frequency is 20kHz, the sampling frequency should not be lower than 1MHz) to capture subtle changes in the duty cycle. Then, the mapping relationship is calculated in real time based on high-speed processing chips such as FPGAs. The corresponding current separation formula is quickly switched according to the change of the switch state to ensure that the separation result can reflect the actual situation of the dual-axis current in real time. At the same time, to verify the separation accuracy, a comparative experiment needs to be designed. Independent current sensors are used to measure the dual-axis current separately and compare it with the separation result. By adjusting the compensation parameters in the separation algorithm, the separation error is controlled within 1%. In addition, the transient process during switch state switching needs to be considered. A transient compensation mechanism is added to the algorithm to avoid the increase of separation error caused by switching action. Finally, accurate separation of the A-axis and B-axis current signals is achieved, providing accurate raw data for subsequent parameter extraction.

[0089] Preferably, the current ripple coefficient extracted by the current parameter extraction module satisfies the following formula:

[0090] ;

[0091] in, This represents the current ripple factor, which is dimensionless. This indicates the peak value of the current signal, measured in amperes (A). This indicates the valley value of the current signal, measured in amperes (A). This represents the effective value of the current signal, measured in amperes (A).

[0092] Meanwhile, the current rising edge slope and current falling edge slope extracted by this module satisfy the following:

[0093] ;

[0094] in, Indicates the current rise slope, in amperes per second (A / s). ); This indicates that the peak value is reached on the rising edge. The current value, in amperes (A); This indicates the current value that reaches 10% of the peak value during the rising edge, and the unit is ampere (A). This indicates that the peak value is reached on the rising edge. The time is in seconds. This indicates that the peak value is reached on the rising edge. The time is expressed in seconds (s); Indicates the slope of the falling edge of the current, in amperes per second (A / s). ); Indicates the drop to the peak value at the middle of the falling edge. The time is expressed in seconds (s); Indicates the drop to the peak value at the middle of the falling edge. The time is expressed in seconds (s).

[0095] Specifically, the current parameter extraction module mainly involves the extraction of current ripple coefficient, rising edge slope, and falling edge slope. These parameters are important indicators for evaluating the quality of current signals and the operating status of motors. The current ripple coefficient reflects the degree of fluctuation of the current signal and is related to the peak, valley, and RMS values ​​of the current. Accurate identification of peak and valley values ​​requires eliminating noise interference in the signal, while the calculation of the RMS value needs to cover the complete current cycle to ensure the accuracy of the results. The rising and falling edge slopes reflect the rate of change of the current signal and are closely related to the current value and timestamp of the feature points. The accurate determination of feature points (such as the 10% peak and 90% peak points) directly affects the accuracy of the slope calculation. In the implementation process, firstly, a high-precision signal conditioning circuit needs to be designed, employing low-noise operational amplifiers and filter networks to reduce the impact of noise on peak and valley value identification. The cutoff frequency of the filter network needs to be reasonably set according to the bandwidth of the current signal, filtering out high-frequency noise while avoiding signal distortion. Secondly, a high-resolution analog-to-digital converter (such as 16-bit precision) is used to sample the current signal, and the sampling rate must satisfy the Nyquist sampling theorem to ensure that the waveform characteristics of the signal can be completely preserved. Then, automatic identification of feature points is achieved through digital signal processing algorithms. A sliding window combined with threshold judgment is used to accurately capture the feature points of peaks, valleys, rising edges, and falling edges. For signals with significant noise interference, multiple sampling can be used. To improve the stability of feature point recognition, a uniform approach is adopted. When calculating the effective value, the integration operation must be strictly performed according to the definition of the effective value, and the integration interval must cover at least one complete current cycle to ensure the accuracy of the calculation results. At the same time, to verify the accuracy of parameter extraction, a standard signal (such as a sine wave signal with known ripple coefficient and slope) can be input, and the extraction results can be compared with the theoretical values. The error can be controlled within the specified range through a calibration algorithm (such as ripple coefficient error less than 0.5% and slope error less than 1%). In addition, the influence of different operating conditions of the motor on parameter extraction should be considered. An operating condition identification mechanism should be added to the algorithm to adopt corresponding extraction strategies for different operating conditions (such as starting, running, and braking) to ensure the adaptability and accuracy of parameter extraction.

[0096] Preferably, the A-axis current sampling accuracy data generated by the sampling accuracy evaluation module and The shaft current sampling accuracy data satisfies the following formula:

[0097] ;

[0098] in, This represents the overall error of the A-axis current sampling, which is dimensionless. This represents the peak measured value of the A-axis current, in amperes (A). This represents the standard peak value of the A-axis current, in amperes (A). This represents the measured effective value of the A-axis current, in amperes (A). This indicates the standard value of the effective value of the A-axis current, in amperes (A). This represents the dimensionless measured value of the A-axis current ripple coefficient. This represents the standard value of the A-axis current ripple coefficient, which is dimensionless. This represents the overall error of the B-axis current sampling, which is dimensionless. This represents the peak measured value of the B-axis current, in amperes (A). This represents the standard value of the peak current along the B-axis, in amperes (A). This represents the measured effective value of the B-axis current, in amperes (A). This represents the standard value of the effective value of the B-axis current, in amperes (A). This represents the measured value of the B-axis current ripple coefficient, which is dimensionless. This represents the standard value of the B-axis current ripple coefficient, which is dimensionless.

[0099] Specifically, the sampling accuracy evaluation module quantifies the sampling accuracy by calculating the comprehensive error of the A-axis and B-axis current sampling. This comprehensive error calculation covers deviations in key parameters such as peak current, RMS current, and ripple coefficient. The deviation calculations for each parameter are compared with preset standard parameters. These standard parameters are determined based on the motor's rated operating conditions and performance indicators, covering ideal parameter values ​​under different speeds and load conditions to provide a reliable benchmark for evaluation. The comprehensive error is obtained by weighted summation of the relative deviations of each parameter. The weighting is determined based on the parameter's impact on motor operation. Peak current and RMS current have a significant impact on motor power and heat generation, therefore they are assigned higher weights, while parameters such as the ripple coefficient are assigned relatively lower weights. During implementation, the first step is to determine the range of various standard parameters based on the motor's rated parameters and design specifications, and store them in the module's standard parameter storage unit. These standard parameters must be updatable via an external interface to accommodate the evaluation needs of different motor models. Secondly, a high-precision data acquisition system is designed to ensure the accuracy of characteristic parameter measurements. Measurement errors are controlled within a small range (e.g., peak measurement error less than 0.5%) through comparison and calibration with a standard signal source. Then, a high-performance microprocessor is used to calculate the deviation and perform a weighted summation of the overall error. The calculation accuracy must meet the evaluation requirements (e.g., floating-point arithmetic accuracy not less than 32 bits) to ensure the accuracy of the calculation results. Simultaneously, to improve the reliability of the evaluation, multiple measurements are performed and averaged to reduce the impact of random errors. The number of measurements is determined based on the evaluation accuracy requirements (e.g., at least 10 measurements). Furthermore, an error analysis mechanism must be established. When the overall error exceeds a preset threshold, the specific deviation parameter can be located, providing a clear direction for subsequent system optimization. Ultimately, accurate A-axis and B-axis current sampling accuracy data is generated, providing a quantitative basis for driver performance evaluation.

[0100] Preferably, when the evaluation result integration module integrates the comprehensive evaluation report, the deviation quantification value of the biaxial current sampling deviation comparison table satisfies the following formula:

[0101] ;

[0102] in, This represents the percentage of relative deviation between the current sampling of the A-axis and B-axis at time t, in units of... This represents the overall error of the A-axis current sampling, which is dimensionless. The A-axis motor phase current at time t is expressed in amperes (A). This represents the overall error of the B-axis current sampling, which is dimensionless. The motor phase current of the B-axis at time t is expressed in amperes (A).

[0103] Meanwhile, the classification of sampling accuracy levels is based on the following formula:

[0104] ;

[0105] Here, Grade represents the sampling accuracy level, which is dimensionless, with levels 1 to 4 corresponding to high accuracy, medium-high accuracy, medium accuracy, and low accuracy, respectively.

[0106] Specifically, the evaluation result integration module mainly involves the calculation of deviation quantification values ​​and the classification of sampling accuracy levels in the dual-axis current sampling deviation comparison table. These are the core components of the comprehensive evaluation report. The deviation quantification value reflects the relative difference in sampling accuracy between the A-axis and B-axis, and is related to the overall error and phase current of the two axes, providing a clear view of the consistency of the two-axis sampling performance. The sampling accuracy level is determined based on the maximum value of the overall error of the two axes. The threshold for level classification needs to be formulated in conjunction with industry standards and actual application requirements. Different levels correspond to different sampling performance levels, providing users with clear evaluation results. During implementation, firstly, the axis priority ranking rules need to be determined. Based on the role of the motor in the system, the priorities of the A-axis and B-axis are determined, and the data is presented in the deviation comparison table according to priority order. Secondly, a real-time calculation algorithm for the deviation quantification value is designed, using a high-precision floating-point arithmetic unit to ensure the accuracy of the results. Simultaneously, a protection mechanism is added to avoid calculation errors, considering the special case of zero phase current. Regarding the accuracy level classification, a reasonable threshold range needs to be determined through extensive experimental data so that the level classification can truly reflect the performance of the sampling system. For example, defining an overall error of less than 0.5% as high precision meets the needs of high-end application scenarios. Then, the comprehensive evaluation report is developed. The software for generating evaluation reports integrates deviation comparison tables, accuracy levels, and error distribution charts according to a standardized format. The reports must include time information and detailed data for key sampling points to facilitate traceability and analysis. To improve readability, data is presented using a combination of charts and graphs, such as bar charts to show dual-axis deviation comparisons and histograms to display error distribution. Furthermore, the software must support the storage and retrieval of evaluation data, using high-capacity storage media to store historical data and a user-friendly interface for rapid data retrieval. Ultimately, the software provides users with a comprehensive, intuitive, and accurate evaluation report, contributing to the performance optimization and quality control of dual-axis low-voltage motor drives.

[0107] Preferably, the biaxial current separation module includes:

[0108] The switching state analysis unit receives the interference-reducing current signal output by the common-mode interference suppression module and synchronously acquires the switching state signals of the A-axis power module and the B-axis power module in the dual-axis motor driver. The switching state signals include the on / off indicators of the upper and lower bridge arm switches of each phase. By performing timing analysis on the switching state signals, the switching state combination in each PWM cycle is determined.

[0109] The current path mapping unit receives the switch state combination output by the switch state analysis unit. Based on the current flow rules under different switch states in the single resistor bus current sampling model, it establishes the correspondence between the switch state combination and the conduction paths of the A-axis current and B-axis current, and clarifies the contribution ratio of the bus current to the A-axis current and B-axis current under different states.

[0110] The separation algorithm execution unit receives the contribution ratio output by the current path mapping unit and the de-interference current signal output by the common-mode interference suppression module. Based on the preset dual-axis current separation algorithm, the de-interference current signal is decomposed into independent A-axis current signal and B-axis current signal according to the contribution ratio. The decomposition process must meet the current conservation constraint under different switching states.

[0111] The separation result verification unit receives the A-axis current signal and B-axis current signal output by the separation algorithm execution unit. By comparing the deviation value between the algebraic sum of the A-axis current signal and the B-axis current signal in the same PWM cycle and the de-interference current signal, if the deviation value exceeds the preset threshold, the separation algorithm execution unit is triggered to re-perform the current separation process.

[0112] Specifically, the dual-axis current separation module includes a switch state analysis unit, a current path mapping unit, a separation algorithm execution unit, and a separation result verification unit. These units work together to achieve accurate separation of the dual-axis current. The core function of the switch state analysis unit is to acquire and analyze the conduction status signals of the power module switching transistors in the dual-axis motor driver in real time. These signals include the on / off indicators of the upper and lower bridge arm switching transistors of each phase. The unit receives these indicators through a high-speed signal acquisition circuit. The response time of the acquisition circuit needs to be controlled within 100ns to ensure accurate capture of high-frequency switching actions. Subsequently, the signal undergoes timing analysis to determine the switching state combination within each PWM cycle. The PWM cycle is typically set between 50μs and 200μs. During the analysis, signal jitter interference needs to be eliminated, and stable identification is achieved by setting a 20ns anti-jitter time window. The current path mapping unit, based on the switch state combination output by the switch state analysis unit, establishes a correspondence between switch states and dual-axis current conduction paths according to the current flow rules under different states in the single-resistor bus current sampling model. It clarifies the contribution ratio of the bus current to the A-axis and B-axis currents under different states. This unit internally stores a preset switch state and current path mapping table, and the update cycle of the mapping table is consistent with the PWM cycle to ensure the real-time nature of the mapping relationship. The separation algorithm execution unit receives the contribution ratio output by the current path mapping unit and the de-interference current signal after common-mode interference suppression. Based on a preset algorithm, it decomposes the de-interference current signal into A-axis and B-axis current signals proportionally. The clock frequency of the algorithm is no less than 100MHz to meet real-time requirements. The decomposition process strictly follows the current conservation constraint, meaning the deviation between the algebraic sum of the decomposed dual-axis currents and the de-interference current signal must be controlled within 0.5%. The separation result verification unit is responsible for comparing the deviation between the algebraic sum of the dual-axis current signals and the interference removal current signal within the same PWM cycle. When the deviation exceeds the preset threshold (usually set to 1%), the separation algorithm execution unit is immediately triggered to re-process the separation. The time overhead of the verification process must be controlled within 10μs to avoid affecting the real-time performance of the overall system. Multiple rounds of verification ensure the accuracy of the separation results and provide a reliable data foundation for subsequent current parameter extraction.

[0113] Preferably, the current parameter extraction module includes:

[0114] The time-domain feature detection unit receives the A-axis current signal and B-axis current signal output by the dual-axis current separation module, performs point-by-point scanning on the A-axis current signal and B-axis current signal, identifies the peak point, valley point, rising edge start point, rising edge end point, falling edge start point and falling edge end point in the signal waveform, and records the current value and timestamp corresponding to each feature point.

[0115] The effective value calculation unit receives the current signal waveform data output by the time domain feature detection unit, and performs integration on the square values ​​of the A-axis current signal and the B-axis current signal within a preset time window according to the definition of the effective value of current. Then, the integration result is divided by the length of the time window and the square root is taken to obtain the effective value of the A-axis current and the effective value of the B-axis current.

[0116] The ripple coefficient analysis unit receives the peak and valley current values ​​output by the time-domain feature detection unit, as well as the effective current value output by the effective value calculation unit. Based on the difference between the peak and valley values ​​and the ratio of the effective current value, the A-axis current ripple coefficient and the B-axis current ripple coefficient are calculated.

[0117] The slope calculation unit receives the current values ​​and timestamps of the rising and falling edge feature points output by the time-domain feature detection unit. It obtains the current rising edge slope by calculating the ratio of the current change from 10% peak value to 90% peak value in the rising edge to the corresponding time change, and obtains the current falling edge slope by calculating the ratio of the current change from 90% peak value to 10% peak value in the falling edge to the corresponding time change.

[0118] Specifically, the current parameter extraction module includes a time-domain feature detection unit, an RMS value calculation unit, a ripple coefficient analysis unit, and a slope calculation unit. These units work collaboratively to extract the dual-axis current characteristic parameters. The main task of the time-domain feature detection unit is to scan the A-axis and B-axis current signals point-by-point, identifying key feature points in the signal waveform. The sampling rate must reach at least 1MHz to capture high-frequency current fluctuations. Identified feature points include peak points, valley points, and the start and end points of rising and falling edges. The current value and timestamp recording accuracy for each feature point are controlled within 0.1% and 10ns, respectively. During the identification process, trend judgment is set using three consecutive sampling points to avoid misjudgments. For example, a peak point must satisfy the condition that the current values ​​of the adjacent points before and after it are all lower than that point. The RMS value calculation unit receives waveform data output from the time-domain feature detection unit. According to the definition of RMS current, it integrates the squared current value within a preset time window, typically set to 10 PWM cycles. The integration operation uses 32-bit floating-point processing to ensure accuracy. The integration result is then divided by the window length and the square root is taken to obtain the dual-axis RMS current value. The calculation error must be controlled within 0.2%. The ripple coefficient analysis unit uses the peak and valley current values ​​output from the time-domain feature detection unit, combined with the RMS value output from the RMS value calculation unit. The ripple coefficient is obtained by dividing the difference between the peak and valley values ​​by the RMS value. During the calculation, a moving average is applied to the peak and valley values, with an average window size of 5 sampling points to reduce the impact of instantaneous fluctuations. The calculation accuracy of the ripple coefficient must reach 0.1%. The slope calculation unit calculates the ratio of the current change from the 10% peak to the 90% peak of the rising edge to the corresponding time change based on the current values ​​and timestamps of the rising and falling edge feature points output by the time-domain feature detection unit, thus obtaining the rising edge slope. Similarly, it calculates the ratio of the falling edge from the 90% peak to the 10% peak to obtain the falling edge slope. The time reference for slope calculation uses a high-precision clock with a clock error of no more than 1ppm, ensuring that the slope calculation error is controlled within 1%. The parameters extracted by each unit are transmitted in real time through the internal bus with a bus transmission rate of no less than 10Mbps to ensure the real-time performance of the parameters.

[0119] Preferably, the sampling accuracy evaluation module includes:

[0120] The standard parameter storage unit stores the standard parameters of the output current of the dual-axis motor driver under different operating conditions. The standard parameters include the rated peak current, rated effective current, maximum allowable ripple coefficient, standard rise slope range, and standard fall slope range of the A-axis and B-axis. The standard parameters can be updated through an external interface.

[0121] The feature parameter comparison unit receives the A-axis and B-axis feature parameters output by the current parameter extraction module and the corresponding standard parameters output by the standard parameter storage unit. It calculates the difference between the current peak value, current effective value, current ripple coefficient, current rise slope and current fall slope one by one to obtain the absolute deviation value of each parameter.

[0122] The deviation quantization unit receives the absolute deviation values ​​output by the feature parameter comparison unit, takes the ratio of the absolute deviation value to the corresponding standard parameter as the relative deviation value, and then integrates the relative deviation values ​​into the A-axis current sampling comprehensive deviation and the B-axis current sampling comprehensive deviation by weighted summation.

[0123] The accuracy level determination unit receives the comprehensive deviation of A-axis current sampling and the comprehensive deviation of B-axis current sampling from the deviation quantization unit, determines the sampling accuracy level of A-axis and B-axis respectively with reference to the preset accuracy level classification threshold, and generates accuracy evaluation data including accuracy level identifier and deviation out-of-tolerance items.

[0124] Specifically, the sampling accuracy evaluation module consists of a standard parameter storage unit, a characteristic parameter comparison unit, a deviation quantification unit, and an accuracy level determination unit. Through the collaborative work of these units, the quantitative evaluation of the dual-axis current sampling accuracy is achieved. The standard parameter storage unit pre-stores standard output current parameters of the dual-axis motor driver under different operating conditions. These parameters include the rated peak current, rated RMS current, maximum allowable ripple coefficient, and standard rise and fall slope ranges for both the A and B axes. The parameters are stored to three decimal places, and the storage medium is non-volatile memory to ensure data is not lost after power failure. It also supports external updates via an RS485 interface with an update rate of at least 9600bps. A data verification mechanism is included during the update process, with the verification error rate controlled within 0.01%. The feature parameter comparison unit receives the dual-axis feature parameters output by the current parameter extraction module and the corresponding standard parameters output by the standard parameter storage unit. It calculates the difference between each parameter to obtain the absolute deviation value. The comparison process must be time-efficient, with the time cost controlled within 50μs to ensure real-time performance. The calculation process uses 32-bit floating-point arithmetic, with an error not exceeding 0.001%. The deviation quantization unit uses the ratio of the absolute deviation value output by the feature parameter comparison unit to the corresponding standard parameter as the relative deviation value. It integrates these relative deviation values ​​into a weighted summation of the dual-axis current sampling comprehensive deviation. The weight allocation is determined based on parameter importance, with peak current and RMS value each accounting for 30%, ripple coefficient for 20%, and rising and falling edge slopes each accounting for 10%. The accuracy of the weighted calculation must reach 0.01%. The accuracy level determination unit receives the dual-axis comprehensive deviation output by the deviation quantization unit, and determines the sampling accuracy level of each axis by referring to the preset accuracy level classification thresholds (e.g., comprehensive deviation less than 0.5% is level 1, 0.5% to 1.0% is level 2, 1.0% to 2.0% is level 3, and greater than or equal to 2.0% is level 4). It then generates accuracy evaluation data containing accuracy level identifiers and deviation out-of-tolerance items. The level determination process must be completed within 10μs. The evaluation data is transmitted to the evaluation result integration module through a high-speed serial interface. The interface transmission bit error rate does not exceed 10^-6 to ensure accurate transmission and subsequent integration of the evaluation data.

[0125] The single-resistor bus current sampling model is the core model for dual-axis current separation in this invention. It captures the bus current signal containing dual-axis motor operating information by setting a single sampling resistor on the bus of the dual-axis low-voltage motor driver. This model clarifies the mapping relationship between the current of each phase of the dual-axis motor and the bus current under different switching states. Based on the on / off state of the power module switching transistors, it analyzes the current conduction path and separates the bus current signal into separate current signals for the A-axis and B-axis. Its function is to solve the current coupling problem when the dual-axis motor shares a sampling resistor, achieving independent extraction of the current of each axis, providing a foundation for subsequent parameter analysis and accuracy evaluation. The significance of this model lies in achieving accurate sampling of dual-axis current with a low-cost and simple structure, overcoming the shortcomings of high cost and complex structure of traditional multi-resistor sampling methods, and improving the economy and reliability of current sampling for dual-axis motor drivers.

[0126] The equivalent common-mode circuit model is the key model for suppressing common-mode interference in this invention. Based on the electromagnetic environment and circuit structure of the dual-axis motor driver, it constructs a common-mode signal path, clarifies the generation and propagation path of common-mode interference, and covers parameters such as parasitic capacitance between the sampling circuit and the power module, and stray capacitance between the sampling circuit and the motor housing. This model designs a common-mode signal path suppression structure to specifically filter out common-mode interference components in the original current signal, reducing the impact of interference on current sampling accuracy. Its function is to quantify the degree of common-mode interference, providing a theoretical basis for the design of the common-mode suppression circuit and effectively improving the signal-to-noise ratio of the current signal. The significance of this model lies in solving the problems of traditional interference suppression methods lacking systematicity and being unable to quantify the impact of interference, ensuring the accuracy of the sampled signal, providing a high-quality signal source for subsequent dual-axis current separation and parameter extraction, and improving the reliability and accuracy of the entire evaluation system.

[0127] like Figure 2 As shown, an output current sampling and evaluation system for a dual-shaft low-voltage motor driver is described. The system operation includes:

[0128] S1. Obtain the original current signal by a single sampling resistor set on the bus of the dual-axis low-voltage motor driver. The original current signal includes bus current fluctuation information during the operation of the dual-axis motor. Transmit the original current signal to the common-mode interference suppression stage.

[0129] S2. Construct a common-mode signal path suppression structure based on the equivalent common-mode circuit model, filter out the common-mode interference components included in the received original current signal, obtain the interference-free current signal, and transmit the interference-free current signal to the biaxial current separation stage.

[0130] S3. Based on the mapping relationship between the phase current of the dual-axis motor and the bus current in the single-resistor bus current sampling model, by analyzing the current conduction path under different switching states, the received interference-removing current signal is separated into the A-axis current signal and B-axis current signal of the corresponding dual-axis motor, and the A-axis current signal and B-axis current signal are transmitted to the current parameter extraction stage.

[0131] S4. Perform time-domain feature analysis on the received A-axis current signal and B-axis current signal, extract feature parameters including current peak value, current effective value, current ripple coefficient, current rise slope and current fall slope, and transmit the feature parameters to the sampling accuracy evaluation stage.

[0132] S5. Based on the preset standard parameter range of the output current of the dual-axis motor driver, by comparing the deviation between the received characteristic parameters and the standard parameters, A-axis current sampling accuracy data and B-axis current sampling accuracy data are generated, and the A-axis current sampling accuracy data and B-axis current sampling accuracy data are transmitted to the evaluation result integration stage.

[0133] S6. According to the axis priority sorting rules of the dual-axis motor driver, integrate the received A-axis current sampling accuracy data and B-axis current sampling accuracy data into a comprehensive evaluation report that includes a dual-axis current sampling deviation comparison table, sampling accuracy level classification and calibration sampling point error distribution.

[0134] This system is designed for evaluating the output current of a dual-axis low-voltage motor driver. Its significant advantage lies in its complete and highly targeted modular architecture, including key components such as single-resistor signal acquisition, common-mode interference suppression, and dual-axis current separation. These modules work collaboratively to achieve a full-process evaluation of the dual-axis output current sampling. The single-resistor signal acquisition module acquires the raw signal with a simple structure; the common-mode interference suppression module specifically handles interference issues; the dual-axis current separation module accurately extracts the characteristics of each axis; the current parameter extraction module comprehensively captures key features; the sampling accuracy evaluation module quantifies deviations; and the evaluation result integration module generates a comprehensive report. The overall design closely revolves around the characteristics of the dual-axis low-voltage motor driver, ensuring the comprehensiveness and professionalism of the evaluation.

[0135] To address the limitations of traditional single-axis evaluation methods in handling dual-axis coupling, this system utilizes a single-resistor bus current sampling model to deeply analyze the coupling relationship between the dual-axis currents. Through a dual-axis current separation module, based on the current conduction paths under different switching states, the mixed current signal is accurately separated into separate current signals for the A-axis and B-axis. This design is specifically tailored to the operating characteristics of dual-axis motors, overcoming the limitation of traditional methods that are only applicable to single axes. It accurately reflects the true current situation of each axis, ensuring that the evaluation results highly match the actual operating state of the dual-axis motor, effectively overcoming the evaluation challenges caused by dual-axis coupling.

[0136] To address the lack of a systematic approach to common-mode interference (CMI) assessment, this system introduces an equivalent common-mode circuit model to construct a common-mode signal path suppression structure, eliminating reliance on simple filtering. The CSI suppression module uses this model to specifically filter out CSI components in the original current signal. Combined with a sampling accuracy assessment module, the system quantifies the impact of interference on sampling accuracy, clearly presenting the deviations it introduces to the current sampling of each axis. This approach, from model construction to interference processing and impact quantification, forms a complete CSI assessment system, replacing the crude processing of traditional simple filtering. It allows for precise control over the impact of CSI on the assessment results, completely resolving the lack of a systematic approach to CSI assessment.

[0137] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0138] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various equivalent changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An output current sampling and evaluation system for a dual-shaft low-voltage motor driver, characterized in that, include: A single-resistor signal acquisition module acquires the raw current signal through a single sampling resistor set on the bus of the dual-axis low-voltage motor driver. The raw current signal includes bus current fluctuation information during the operation of the dual-axis motor. The signal output terminal of this module is connected to the signal input terminal of the common-mode interference suppression module. The common-mode interference suppression module receives the raw current signal output by the single-resistor signal acquisition module, constructs a common-mode signal path suppression structure based on an equivalent common-mode circuit model, and filters out the common-mode interference components included in the raw current signal. The signal output terminal of this module is connected to the signal input terminal of the dual-axis current separation module. The dual-axis current separation module receives the de-interference current signal output by the common-mode interference suppression module. Based on the mapping relationship between the phase currents of the dual-axis motor and the bus current in the single-resistor bus current sampling model, it separates the de-interference current signal into the corresponding A-axis and B-axis current signals of the dual-axis motor by analyzing the current conduction paths under different switching states. The signal output terminal of this module is connected to the signal input terminal of the current parameter extraction module. The current parameter extraction module receives the A-axis and B-axis current signals output by the dual-axis current separation module, performs time-domain feature analysis on the A-axis and B-axis current signals, and extracts feature parameters including current peak value, current RMS value, current ripple coefficient, current rise slope, and current fall slope. The signal output terminal of this module is connected to the signal input terminal of the sampling accuracy evaluation module.

2. The output current sampling and evaluation system for a dual-axis low-voltage motor driver according to claim 1, characterized in that, The sampling accuracy evaluation module receives various characteristic parameters output by the current parameter extraction module, combines them with the preset standard parameter range of the output current of the dual-axis motor driver, and generates A-axis current sampling accuracy data and B-axis current sampling accuracy data by comparing the degree of deviation between the characteristic parameters and the standard parameters. The signal output terminal of this module is connected to the signal input terminal of the evaluation result integration module. The evaluation result integration module receives the A-axis current sampling accuracy data and B-axis current sampling accuracy data output by the sampling accuracy evaluation module. According to the axis priority sorting rules of the dual-axis motor driver, the A-axis current sampling accuracy data and B-axis current sampling accuracy data are integrated into a comprehensive evaluation report including a dual-axis current sampling deviation comparison table, sampling accuracy level classification and calibration sampling point error distribution. The common-mode interference suppression module is based on a common-mode signal path suppression structure constructed using an equivalent common-mode circuit model, and satisfies the following formula: ； in, Indicates the equivalent common-mode capacitance; This represents the parasitic capacitance between the single-resistance signal acquisition module and the A-axis motor power module; This represents the parasitic capacitance between the single-resistance signal acquisition module and the B-axis motor power module; This represents the stray capacitance between the sampling circuit and the motor housing; Meanwhile, the module's suppression of common-mode interference satisfies the following: ； in, Indicates the common-mode rejection ratio; Indicates the common-mode interference input voltage; Indicates the common-mode interference output voltage; Indicates the angular frequency of the common-mode interference signal; This represents the suppression resistor in a common-mode rejection circuit; This represents a differential capacitor.

3. The output current sampling and evaluation system for a dual-axis low-voltage motor driver according to claim 1, characterized in that, In the single-resistance bus current sampling model upon which the dual-axis current separation module is based, the mapping relationship between the phase current of the dual-axis motor and the bus current satisfies the following formula: ； in, This represents the bus current at time t; This represents the A-axis current mapping coefficient, the value of which is determined by the ratio of the on-state voltage drop of the A-axis motor power transistor to the resistance value of the sampling resistor; This represents the A-axis motor phase current at time t; This represents the switching duty cycle of the A-axis motor power module at time t, with a value ranging from 0 to 1. This represents the B-axis current mapping coefficient, the value of which is determined by the ratio of the on-state voltage drop of the B-axis motor power transistor to the resistance value of the sampling resistor. This represents the B-axis motor phase current at time t; This represents the duty cycle of the B-axis motor power module at time t, with a value ranging from 0 to 1. The formula is obtained through analysis. shaft current signal and The separation expression for the shaft current signal is: 。 4. The output current sampling and evaluation system for a dual-axis low-voltage motor driver according to claim 1, characterized in that, The current ripple coefficient extracted by the current parameter extraction module satisfies the following formula: ； in, Indicates the current ripple factor; Indicates the peak value of the current signal; Represents the valley value of the current signal; This represents the effective value of the current signal; Meanwhile, the current rising edge slope and current falling edge slope extracted by this module satisfy the following: ； in, Indicates the slope of the current rising edge; Indicates that the peak value is reached on the rising edge. The current value; This indicates the current value that reaches 10% of the peak value during the rising edge; Indicates that the peak value is reached on the rising edge. The moment Indicates that the peak value is reached on the rising edge. The moment; Indicates the slope of the falling edge of the current; Indicates the drop to the peak value at the middle of the falling edge. The moment; Indicates the drop to the peak value at the middle of the falling edge. At that moment.

5. The output current sampling and evaluation system for a dual-axis low-voltage motor driver according to claim 2, characterized in that, The A-axis current sampling accuracy data and B-axis current sampling accuracy data generated by the sampling accuracy evaluation module satisfy the following formula: ； in, This indicates the overall error of the A-axis current sampling; This indicates the measured peak value of the A-axis current; This indicates the standard value of the peak A-axis current; This represents the measured effective value of the A-axis current. This indicates the standard value of the effective value of the A-axis current; This represents the measured value of the A-axis current ripple coefficient; This represents the standard value of the A-axis current ripple factor; This indicates the overall error of the B-axis current sampling; This indicates the measured peak value of the B-axis current. This indicates the standard value of the B-axis current peak. This represents the measured effective value of the B-axis current. This indicates the standard value of the effective value of the B-axis current; This represents the measured value of the B-axis current ripple coefficient; This represents the standard value of the B-axis current ripple coefficient.

6. The output current sampling and evaluation system for a dual-axis low-voltage motor driver according to claim 2, characterized in that, When the evaluation result integration module integrates the comprehensive evaluation report, the deviation quantification value of the biaxial current sampling deviation comparison table satisfies the following formula: ； in, This represents the percentage of relative deviation between the current sampling of the A-axis and B-axis at time t. This indicates the overall error of the A-axis current sampling; This represents the A-axis motor phase current at time t; This indicates the overall error of the B-axis current sampling; This represents the B-axis motor phase current at time t; Meanwhile, the classification of sampling accuracy levels is based on the following formula: ； Here, Grade represents the sampling accuracy level, with levels 1 to 4 corresponding to high accuracy, medium-high accuracy, medium accuracy, and low accuracy, respectively.

7. The output current sampling and evaluation system for a dual-axis low-voltage motor driver according to claim 1, characterized in that, The dual-axis current separation module includes: The switching state analysis unit receives the interference-reducing current signal output by the common-mode interference suppression module and synchronously acquires the switching state signals of the A-axis power module and the B-axis power module in the dual-axis motor driver. The switching state signals include the on / off indicators of the upper and lower bridge arm switches of each phase. By performing timing analysis on the switching state signals, the switching state combination in each PWM cycle is determined. The current path mapping unit receives the switch state combination output by the switch state analysis unit. Based on the current flow rules under different switch states in the single resistor bus current sampling model, it establishes the correspondence between the switch state combination and the conduction paths of the A-axis current and B-axis current, and clarifies the contribution ratio of the bus current to the A-axis current and B-axis current under different states. The separation algorithm execution unit receives the contribution ratio output by the current path mapping unit and the de-interference current signal output by the common-mode interference suppression module. Based on the preset dual-axis current separation algorithm, the de-interference current signal is decomposed into independent A-axis current signal and B-axis current signal according to the contribution ratio. The decomposition process must meet the current conservation constraint under different switching states. The separation result verification unit receives the A-axis current signal and B-axis current signal output by the separation algorithm execution unit. By comparing the deviation value between the algebraic sum of the A-axis current signal and the B-axis current signal in the same PWM cycle and the de-interference current signal, if the deviation value exceeds the preset threshold, the separation algorithm execution unit is triggered to re-perform the current separation process.

8. The output current sampling and evaluation system for a dual-axis low-voltage motor driver according to claim 1, characterized in that, The current parameter extraction module includes: The time-domain feature detection unit receives the A-axis current signal and B-axis current signal output by the dual-axis current separation module, performs point-by-point scanning on the A-axis current signal and B-axis current signal, identifies the peak point, valley point, rising edge start point, rising edge end point, falling edge start point and falling edge end point in the signal waveform, and records the current value and timestamp corresponding to each feature point. The effective value calculation unit receives the current signal waveform data output by the time domain feature detection unit, and performs integration on the square values ​​of the A-axis current signal and the B-axis current signal within a preset time window according to the definition of the effective value of current. Then, the integration result is divided by the length of the time window and the square root is taken to obtain the effective value of the A-axis current and the effective value of the B-axis current. The ripple coefficient analysis unit receives the peak and valley current values ​​output by the time-domain feature detection unit, as well as the effective current value output by the effective value calculation unit. Based on the difference between the peak and valley values ​​and the ratio of the effective current value, the A-axis current ripple coefficient and the B-axis current ripple coefficient are calculated. The slope calculation unit receives the current values ​​and timestamps of the rising and falling edge feature points output by the time-domain feature detection unit. It obtains the current rising edge slope by calculating the ratio of the current change from 10% peak value to 90% peak value in the rising edge to the corresponding time change, and obtains the current falling edge slope by calculating the ratio of the current change from 90% peak value to 10% peak value in the falling edge to the corresponding time change.

9. The output current sampling and evaluation system for a dual-axis low-voltage motor driver according to claim 2, characterized in that, The sampling accuracy evaluation module includes: The standard parameter storage unit stores the standard parameters of the output current of the dual-axis motor driver under different operating conditions. The standard parameters include the rated peak current, rated effective current, maximum allowable ripple coefficient, standard rise slope range, and standard fall slope range of the A-axis and B-axis. The standard parameters are updated through an external interface. The feature parameter comparison unit receives the A-axis and B-axis feature parameters output by the current parameter extraction module and the corresponding standard parameters output by the standard parameter storage unit. It calculates the difference between the current peak value, current effective value, current ripple coefficient, current rise slope and current fall slope one by one to obtain the absolute deviation value of each parameter. The deviation quantization unit receives the absolute deviation values ​​output by the feature parameter comparison unit, takes the ratio of the absolute deviation value to the corresponding standard parameter as the relative deviation value, and then integrates the relative deviation values ​​into the A-axis current sampling comprehensive deviation and the B-axis current sampling comprehensive deviation by weighted summation. The accuracy level determination unit receives the comprehensive deviation of A-axis current sampling and the comprehensive deviation of B-axis current sampling from the deviation quantization unit, determines the sampling accuracy level of A-axis and B-axis respectively with reference to the preset accuracy level classification threshold, and generates accuracy evaluation data including accuracy level identifier and deviation out-of-tolerance items.

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