A Method, System and Device for Suppressing Nonlinear Error of Pulse Width Modulation Dead Time

Abstract

The present invention relates to a method, system and device for suppressing non-linear errors in the dead time of pulse width modulation. The method includes: obtaining delay characteristic data and PWM signal parameters of a switching device in a target circuit, and performing initialization parameter configuration to obtain initial configuration parameters; obtaining real-time current data of the target circuit, comparing and compensating it with the initial configuration parameters to obtain a dynamic compensation interval; obtaining the actual conduction state of the switching device, adjusting the dead time according to the dynamic compensation interval for the actual conduction state to obtain a critical safety dead time value; performing duty cycle correction based on the critical safety dead time value and the dynamic compensation interval to obtain a directional compensation amount; verifying the waveform harmonic distortion degree and dynamic response of the directional compensation amount and the initial configuration parameters to obtain a dead time compensation control strategy. The present invention can more accurately evaluate the dead time requirements under actual working conditions and improve the accuracy of dead time compensation.

Description

Technical Field

[0001] The present invention relates to the technical field of pulse width modulation, and particularly relates to a method, system and device for suppressing dead-time non-linear error in pulse width modulation. Background Art

[0002] Pulse width modulation (PWM) technology, as an important power electronics control method, has been widely applied in modern power electronics devices such as frequency converters and motor drives. With the continuous improvement of industrial automation and precision control requirements, how to effectively suppress the dead-time non-linear error in PWM control to achieve high-precision operation and performance optimization of the system has become one of the key research topics. Existing dead-time compensation methods usually only focus on the fixed delay characteristics of switching devices or only consider the judgment of a single current direction, while ignoring the comprehensive influence of factors such as current and temperature on the switching characteristics during actual operation. This simplified compensation strategy often fails to accurately handle the dead-time non-linear effect under actual working conditions, resulting in waveform distortion of the system output and degradation of dynamic response performance, ultimately affecting the performance of the entire control system. Summary of the Invention

[0003] The main object of the present invention is to provide a method, system and device for suppressing dead-time non-linear error in pulse width modulation, which can more accurately evaluate the dead-time requirements under actual working conditions and improve the accuracy of dead-time compensation.

[0004] To achieve the above object, the present invention provides a method for suppressing dead-time non-linear error in pulse width modulation, including:

[0005] Obtaining the delay characteristic data of the switching device of the target circuit and the PWM signal parameters, and performing initialization parameter configuration to obtain the initial configuration parameters;

[0006] Obtaining the real-time current data of the target circuit, comparing it with the initial configuration parameters for compensation to obtain the dynamic compensation interval;

[0007] Obtaining the actual conduction state of the switching device, and adjusting the dead-time according to the dynamic compensation interval for the actual conduction state to obtain the critical safety dead-time value;

[0008] Based on the critical safety dead-time value and the dynamic compensation interval, performing duty cycle correction to obtain the directional compensation amount;

[0009] Verifying the waveform harmonic distortion and dynamic response of the directional compensation amount and the initial configuration parameters to obtain the dead-time compensation control strategy.

[0010] Further, the obtaining the delay characteristic data of the switching device of the target circuit and the PWM signal parameters, and performing initialization parameter configuration to obtain the initial configuration parameters includes:

[0011] Perform switching timing analysis on the delay characteristic data to obtain the turn-on delay time, turn-off delay time, and on-resistance value of the switching device;

[0012] Perform device time analysis based on the turn-on delay time and the turn-off delay time to obtain the total delay time and the critical conduction time;

[0013] Perform temperature coefficient correction on the total delay time and the critical conduction time, and perform voltage drop compensation based on the on-resistance value to obtain corrected delay parameters;

[0014] Extract sampling window parameters from the PWM signal according to the corrected delay parameters to obtain PWM signal parameters including duty cycle parameters, frequency parameters, and edge time parameters;

[0015] Perform piecewise linear interpolation compensation calculation based on the corrected delay parameters and the PWM signal parameters to obtain the initial dead time compensation time;

[0016] Perform boundary limiting processing on the initial dead time compensation time, and perform dynamic configuration adjustment based on the PWM signal parameters to obtain initial configuration parameters.

[0017] Further, obtain the real-time current data of the target circuit, and perform compensation comparison with the initial configuration parameters to obtain a dynamic compensation interval, including:

[0018] Perform Fourier transform processing on the real-time current data to obtain current spectrum component data;

[0019] Perform current waveform reconstruction on the current spectrum component data to obtain reconstructed current waveform data;

[0020] Perform zero-crossing detection on the reconstructed current waveform data to obtain a current zero-crossing time sequence;

[0021] Perform switching timing comparison on the initial configuration parameters according to the current zero-crossing time sequence to obtain phase deviation data;

[0022] Perform compensation interval statistics on the phase deviation data to obtain the range of the dead time compensation interval;

[0023] Perform dynamic piecewise mapping on the initial configuration parameters according to the range of the dead time compensation interval to obtain a dynamic compensation interval.

[0024] Further, obtain the actual conduction state of the switching device, and perform dead time adjustment on the actual conduction state according to the dynamic compensation interval to obtain a critical safety dead time value, including:

[0025] Sample and detect the conduction voltage and conduction current of the switch device to obtain the actual conduction state;

[0026] Calculate the conduction and turn-off moments of the switch device based on the actual conduction state to obtain the actual switch timing;

[0027] Calculate the time interval of the actual switch timing to obtain the actual dead time;

[0028] Compare and calculate the upper and lower limits of the actual dead time with the dynamic compensation interval to obtain the dead time deviation;

[0029] Calculate the conduction delay compensation coefficient and turn-off delay compensation coefficient for the actual switch timing, and perform dead time compensation on the dead time deviation to obtain the compensated dead time;

[0030] Verify the safety margin of the compensated dead time to obtain the critical safety dead time value.

[0031] Further, performing duty cycle correction based on the critical safety dead time value and the dynamic compensation interval to obtain the directional compensation amount, including:

[0032] Perform sequential sampling on the critical safety dead time value and the dynamic compensation interval to obtain a dead time compensation sampling sequence;

[0033] Perform PWM waveform transformation on the dead time compensation sampling sequence to obtain frequency domain waveform characteristic data;

[0034] Extract harmonic components from the frequency domain waveform characteristic data to obtain fundamental components and high-order harmonic components;

[0035] Perform PWM waveform phase correction based on the fundamental component and the high-order harmonic component to obtain a phase compensation coefficient;

[0036] Perform non-linear correction mapping on the phase compensation coefficient to obtain a duty cycle correction amount;

[0037] Perform PWM waveform compensation based on the duty cycle correction amount to obtain an initial compensation amount;

[0038] Perform waveform direction filtering on the initial compensation amount to obtain the directional compensation amount.

[0039] Further, verifying the waveform harmonic distortion and dynamic response of the directional compensation amount and the initial configuration parameters to obtain a dead time compensation control strategy, including:

[0040] Perform quantitative evaluation and calculation of the harmonic distortion of the directional compensation amount to obtain harmonic distortion evaluation data;

[0041] Perform dynamic response characteristic analysis on the directional compensation amount to obtain a dynamic response performance evaluation result;

[0042] Based on the harmonic distortion evaluation data and the dynamic response performance evaluation, construct a strategy for the initial configuration parameters to obtain an initial dead zone compensation strategy;

[0043] Perform simulation verification on the initial dead zone compensation strategy to obtain a dead zone simulation verification result;

[0044] According to the dead zone simulation verification result, correct the parameters of the initial dead zone compensation strategy to obtain the dead zone compensation control strategy.

[0045] Furthermore, the quantitative evaluation calculation of the harmonic distortion degree of the directional compensation amount to obtain harmonic distortion evaluation data includes:

[0046] Separate the components of the directional compensation amount to obtain the fundamental wave amplitude and the amplitudes of each harmonic;

[0047] Perform harmonic statistics on the fundamental wave amplitude and the amplitudes of each harmonic to obtain a harmonic amplitude sequence;

[0048] Calculate the content of each harmonic in the harmonic amplitude sequence to obtain the total harmonic distortion;

[0049] Perform distribution analysis on the total harmonic distortion to obtain harmonic distribution data;

[0050] Construct a function based on the harmonic distribution data to obtain a harmonic distribution density function;

[0051] Perform distortion index operations on the harmonic distribution density function to obtain an accumulated harmonic distortion index;

[0052] Quantitatively evaluate the harmonic distortion degree according to the accumulated harmonic distortion index to obtain the harmonic distortion evaluation data.

[0053] The present invention also provides a pulse width modulation dead zone non-linear error suppression system, which is applied to the pulse width modulation dead zone non-linear error suppression method described in any one of the above, and includes:

[0054] An acquisition module, which is used to obtain the delay characteristic data and PWM signal parameters of the switching device of the target circuit, and perform initialization parameter configuration to obtain the initial configuration parameters;

[0055] An analysis module, which is used to obtain the real-time current data of the target circuit, compare it with the initial configuration parameters for compensation, and obtain a dynamic compensation interval;

[0056] An association module, which is used to obtain the actual conduction state of the switching device, adjust the dead time of the actual conduction state according to the dynamic compensation interval, and obtain a critical safety dead time value;

[0057] A processing module, which is used to perform duty cycle correction based on the critical safety dead time value and the dynamic compensation interval to obtain a directional compensation amount;

[0058] A control module, which is used to perform waveform harmonic distortion and dynamic response test verification on the directional compensation amount and the initial configuration parameters to obtain a dead time compensation control strategy.

[0059] The present invention also provides a device for suppressing the non-linear error of the PWM dead time, including:

[0060] A memory for storing programs;

[0061] A processor for executing the program to implement each step of the method for suppressing the non-linear error of the PWM dead time described in any one of the above.

[0062] A method, a system and a device for suppressing the non-linear error of the PWM dead time provided by the present invention have the following beneficial effects:

[0063] By comprehensively analyzing the delay characteristics of the switching device and the PWM signal parameters, and combining real-time current data for dynamic compensation, the dead time requirements under actual working conditions can be more accurately evaluated, thereby improving the accuracy of dead time compensation and providing a more reliable basis for system control. By compensating and comparing the real-time current data with the initial configuration parameters and adjusting the dead time according to the dynamic compensation interval, the refined control of the conduction state of the switching device is realized, which helps to reduce the switching loss and avoid over-compensation. The directional correction of the duty cycle based on the critical safety dead time value can ensure that the system can maintain good output waveform quality under different working conditions, reduce harmonic distortion, and improve the dynamic response performance of the system. By comprehensively analyzing the dead time compensation amount and the initial configuration parameters, a more reasonable compensation control strategy is formulated, and the optimal operation of the entire system is realized through waveform harmonic distortion and dynamic response test verification, thereby effectively suppressing the non-linear error of the dead time and improving the control accuracy of the system. At the same time, by considering the influence of current changes on the switching characteristics, the dead time compensation strategy can be flexibly adjusted according to the characteristics and demand changes under different working conditions, making the system more adaptable to complex operating scenarios. Description of the Drawings

[0064] Figure 1 It is a flowchart of a method for suppressing the non-linear error of the PWM dead time provided by the present invention;

[0065] Figure 2 This invention provides a structure diagram of a pulse width modulation dead-time non-linear error suppression system;

[0066] Figure 3 This invention provides a structure diagram of a pulse width modulation dead-time non-linear error suppression device.

[0067] The realization, functional features and advantages of the objectives of this invention will be further described with reference to the embodiments and the attached drawings. Detailed implementation manners

[0068] In order to make the objectives, technical solutions and advantages of this invention clearer and more understandable, the following further details this invention in combination with the attached drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this invention and not to limit this invention.

[0069] Next, this invention will be further described in combination with the attached drawings and the specific implementation manners.

[0070] Referring to Figure 1 as shown, this invention provides 1. A pulse width modulation dead-time non-linear error suppression method, characterized by including:

[0071] Step S1: Obtain the delay characteristic data of the switching device of the target circuit and the PWM signal parameters, and perform initial parameter configuration to obtain the initial configuration parameters;

[0072] Step S2: Obtain the real-time current data of the target circuit, perform compensation comparison with the initial configuration parameters to obtain the dynamic compensation interval;

[0073] Step S3: Obtain the actual conduction state of the switching device, and adjust the dead-time according to the dynamic compensation interval to obtain the critical safety dead-time value;

[0074] Step S4: Perform duty cycle correction based on the critical safety dead-time value and the dynamic compensation interval to obtain the directional compensation amount;

[0075] Step S5: Perform waveform harmonic distortion and dynamic response test verification on the directional compensation amount and the initial configuration parameters to obtain the dead-time compensation control strategy.

[0076] Based on the steps shown above, the detailed step process is as follows:

[0077] Step S1: Obtain key timing parameters such as turn-on delay time td(on), turn-off delay time td(off), rise time tr, and fall time tf of the switching device (such as MOSFET, IGBT, etc.) through experimental measurement or by referring to the device manual. For PWM signal parameters, it includes basic parameters such as carrier frequency fc, modulation ratio M, and dead time Td. Input these parameters into the controller for initial configuration. Specifically, when implementing, use an oscilloscope to measure the delay characteristic curves of the switching device under different junction temperatures and different drive voltages, and establish a delay characteristic database in the form of a look-up table. At the same time, according to the requirements of the application scenario, set an appropriate PWM carrier frequency (usually from a few kHz to dozens of kHz), modulation ratio range (between 0 and 1), and initial dead time (usually from a few hundred ns to a few μs). These initial configuration parameters will be used as the reference values for subsequent dynamic compensation.

[0078] Step S2: Use a current sensor to continuously collect the load current in the circuit and input it into the controller after ADC conversion. Based on the initially configured dead time parameter, analyze the deviation between the actual current waveform and the ideal PWM waveform. Determine the upper and lower limit ranges of dynamic compensation by establishing the mapping relationship between the current sampling value and the dead time. The determination of the compensation interval takes into account the influence of factors such as current magnitude, current direction, and switching frequency. When the current is large, due to the more significant Miller effect of the switching device, the compensation interval increases accordingly; when the current is small, the compensation interval decreases accordingly. The setting of this dynamic compensation interval ensures the accuracy and reliability of the dead time adjustment.

[0079] Step S3: Determine the actual conduction state of the switching device by collecting the voltage signal across the switching device. Use a comparator circuit to detect the drain-source (or collector-emitter) voltage of the switch tube to determine whether the switch tube is fully conducting or turned off. Combine the obtained dynamic compensation interval to adjust the dead time in real time. Ensure that the upper and lower arm switch tubes do not conduct simultaneously during the adjustment process to avoid shoot-through phenomenon. The determination of the critical safety dead time value is based on the actual switching characteristics of the switching device and the load current conditions, and the dead time is minimized as much as possible while ensuring the safety of the switch. This value is dynamically updated with the change of the load condition, realizing the adaptive adjustment of the dead time.

[0080] Step S4: Calculate the duty cycle correction value of the PWM waveform through the critical safety dead zone value and the dynamic compensation interval. The duty cycle correction process takes into account the influence of the current direction, and different compensation strategies are adopted for positive and negative currents respectively. When the current is positive, the turn-off delay of the lower-arm switch tube will cause the actual duty cycle to be greater than the given value, and the compensation amount is negative; when the current is negative, the turn-off delay of the upper-arm switch tube will cause the actual duty cycle to be less than the given value, and the compensation amount is positive. The magnitude of the compensation amount has a non-linear relationship with the current amplitude and the switching frequency, and is calculated through a look-up table or a mathematical model. The corrected duty cycle ensures the symmetry of the output voltage and reduces the waveform distortion caused by the dead zone effect. The calculation of the directional compensation amount also takes into account the influence of the temperature characteristics and load characteristics of the switching device, realizing precise control of the compensation.

[0081] Step S5: Compare the output voltage waveforms before and after compensation through FFT analysis, and calculate the total harmonic distortion THD. Adopt a step response test to evaluate the dynamic characteristics of the system, including indicators such as rise time, overshoot, and settling time. Based on the test results, optimize and adjust the compensation strategy, including the range of the compensation interval, the calculation method of the compensation amount, etc. The final determination of the dead zone compensation control strategy comprehensively considers the steady-state performance and dynamic performance of the system. The implementation of the control strategy uses a digital controller, and functions such as parameter configuration, data acquisition, compensation calculation, and PWM output are realized through program code. The effectiveness of the compensation control strategy is verified through experiments under different working conditions, including different modulation ratios, different load conditions, and different temperature environments.

[0082] A method for suppressing the non-linear error of the PWM dead zone provided by the present invention can more accurately evaluate the dead zone requirements under actual working conditions by comprehensively analyzing the delay characteristics of the switching device and the PWM signal parameters and combining real-time current data for dynamic compensation, thereby improving the accuracy of dead zone compensation and providing a more reliable basis for system control. By comparing and compensating the real-time current data with the initial configuration parameters and adjusting the dead zone time according to the dynamic compensation interval, the refined control of the conduction state of the switching device is realized, which helps to reduce the switching loss and avoid over-compensation. The directional correction of the duty cycle based on the critical safety dead zone value can ensure that the system can maintain good output waveform quality under different working states, reduce harmonic distortion, and improve the dynamic response performance of the system. By comprehensively analyzing the dead zone compensation amount and the initial configuration parameters, a more reasonable compensation control strategy is formulated, and the optimal operation of the entire system is realized through the verification of the waveform harmonic distortion degree and the dynamic response test, thereby effectively suppressing the non-linear error of the dead zone and improving the control accuracy of the system. At the same time, by considering the influence of current changes on the switching characteristics, the dead zone compensation strategy can be flexibly adjusted according to the characteristics and demand changes under different working conditions, making the system more adaptable to complex operating scenarios.

[0083] In one embodiment, delay characteristic data of the switching device of the target circuit and PWM signal parameters are acquired, and initial parameter configuration is performed. The obtained initial configuration parameters include:

[0084] The voltage and current waveforms of the switching device in different operating states are collected by an oscilloscope. The sampling frequency is set to 100 times the switching frequency, and the sampling duration is 1000 switching cycles to ensure the integrity and representativeness of the data.

[0085] During the switching timing analysis process, the collected waveform data is processed. The measurement start point of the turn-on delay time td(on) is the transition point of the drive signal level from low to high, and the end point is the moment when the current of the switching device starts to rise. The measurement start point of the turn-off delay time td(off) is the transition point of the drive signal level from high to low, and the end point is the moment when the current of the switching device starts to fall. The on-resistance value Ron is calculated by the ratio of the voltage to the current in the fully-conducted state of the switching device, and the average value of 100 cycles is taken as the final result.

[0086] In the device time analysis stage, the measured turn-on delay time td(on) and turn-off delay time td(off) are added to obtain the total delay time. The determination of the critical conduction time tc is achieved by analyzing the rising segment of the current waveform of the switching device, which is the time interval from when the current starts to rise to when it reaches the stable value. This time reflects the transition process of the switching device from the start of conduction to full conduction.

[0087] In the temperature coefficient correction section, the switching device is tested at different temperature points to establish the correspondence between temperature and delay time. The temperature change range is from -40 degrees Celsius to +125 degrees Celsius, and a set of data is recorded every 25 degrees. The temperature coefficient is obtained by interpolation method and used to correct the total delay time and the critical conduction time tc. The voltage drop compensation is based on the on-resistance value, taking into account the influence of the voltage drop in the conducting state of the switching device on the delay characteristics, and the corrected delay parameters are comprehensively obtained.

[0088] During the process of extracting the pulse width modulation signal parameters, the width of the sampling window is set to 5 times the corrected delay parameter. Within this window, the duty cycle parameter D is obtained through level detection, the frequency parameter is obtained through signal period measurement, and the edge time parameters tr (rise time) and tf (fall time) are obtained through level transition time measurement. The average value of multiple cycles is taken for each parameter to eliminate the influence of random fluctuations.

[0089] In the piecewise linear interpolation compensation calculation stage, the switching frequency f range is divided into multiple intervals. The interval division principle is to ensure that the change of the delay characteristics within each interval is approximately linear. Within each interval, according to the corrected delay parameter and the PWM signal parameters (D, f, tr, tf), the dead-time compensation time of this interval is calculated through linear interpolation.

[0090] During the boundary clipping process, the minimum compensation time is set to the smaller value of the turn-on delay time and the turn-off delay time, and the maximum compensation time is set to the total delay time. Compensation times outside this range will be limited to the boundary values. The dynamic configuration adjustment finely tunes the compensation time based on the PWM signal parameters measured in real time, with an adjustment step of one-thousandth of the original compensation time, finally obtaining the initial configuration parameters to ensure the smoothness of the system response.

[0091] In this embodiment, through the high-precision acquisition and systematic analysis of the delay characteristic data of the switching device, accurate measurement of the turn-on delay time, turn-off delay time, and on-resistance value is achieved, laying a foundation for the precise compensation of the dead time. A multi-level correction mechanism using temperature coefficient correction and voltage drop compensation effectively eliminates the influence of temperature changes and on-state voltage drops on the delay characteristics, significantly improving the accuracy of the compensation parameters. The compensation calculation method based on piecewise linear interpolation enables accurate dead-time compensation times to be obtained in different switching frequency intervals, overcoming the limitations of traditional fixed dead-time compensation schemes. Through the boundary clipping and dynamic configuration adjustment mechanisms, both the effectiveness of the compensation time is ensured and real-time response to changes in PWM signal parameters is achieved, enhancing the dynamic adaptability of the system. This method establishes a complete parameter recording system, facilitating online optimization and fault diagnosis of the system, and improving the reliability and maintainability of dead-time nonlinear error suppression.

[0092] In one embodiment, real-time current data of the target circuit is obtained and compared with the initial configuration parameters for compensation to obtain a dynamic compensation interval, including:

[0093] The dynamic configuration adjustment process of the pulse width modulation signal parameters is achieved by adjusting parameters such as the carrier frequency, modulation ratio, and dead time. The carrier frequency determines the operating frequency of the switching transistor, the modulation ratio controls the magnitude of the output voltage, and the dead time prevents the upper and lower bridge arm switching transistors from conducting simultaneously. The adjustment of these parameters follows the requirements of circuit stability and generates the initial configuration parameters on the premise of ensuring the safe operation of the system.

[0094] The real-time current data of the target circuit is obtained by sampling with a closed-loop Hall current sensor. The sampling frequency of the sensor is set to twenty times the carrier frequency, and the sampling accuracy is sixteen bits. The sampled data undergoes anti-aliasing filtering to eliminate high-frequency interference components and ensure the validity of the sampled data.

[0095] The Fourier transform process converts the sampled time-domain current data into the frequency domain. The transformation process uses a fast algorithm based on radix-2 decimation to decompose the continuous current data into sine components of different frequencies. Each frequency component contains two characteristic quantities, amplitude and phase, and these characteristic quantities together constitute the current spectrum component data.

[0096] Current waveform reconstruction is a key step in processing spectral component data. When reconstructing, the frequency components that have a significant impact on the current characteristics are retained, including the fundamental wave and harmonic components with amplitudes exceeding 5% of the fundamental wave. By superimposing these main components, the main characteristics of the current waveform are restored to obtain the reconstructed current waveform data.

[0097] Zero-crossing detection is to find the time points when the current value changes from positive to negative or from negative to positive in the reconstructed current waveform data. The detection uses the three-point linear interpolation method to accurately locate the zero-crossing moment between sampling points. All detected zero-crossing moments are arranged in chronological order to form a current zero-crossing moment sequence.

[0098] Switching timing comparison is to compare the current zero-crossing moment sequence with the theoretical switching timing in the initial configuration parameters. During the comparison process, the time difference between the actual zero-crossing moment and the theoretical switching moment is calculated, and these time differences are converted into phase angles to obtain the phase deviation data.

[0099] Dead zone compensation interval statistics is to quantitatively analyze the phase deviation data. In the statistical process, the maximum value, minimum value, and mean value of the deviation are calculated, and the upper and lower limits of the dead zone compensation interval are determined based on these statistical characteristics. The range of the compensation interval directly affects the adjustment range of the dead zone time.

[0100] Dynamic segmented mapping is to divide the range of the dead zone compensation interval into multiple sub-intervals. Each sub-interval corresponds to a different working state and uses a different compensation coefficient. The mapping relationship takes into account the non-linear characteristics of the phase deviation to achieve precise compensation at different working points, and finally obtains the dynamic compensation interval.

[0101] In this embodiment, by performing Fourier transform processing and waveform reconstruction on real-time current data, the main characteristics of the current waveform can be accurately captured, high-frequency noise interference can be effectively filtered, and the analysis accuracy of the current signal is improved. The use of a high-precision closed-loop Hall current sensor and anti-aliasing filtering processing ensures the accuracy and effectiveness of the sampled data, providing a reliable data basis for subsequent dead zone compensation. Through the three-point linear interpolation method for zero-crossing detection, the current zero-crossing moment is accurately located, and combined with the switching timing comparison, the characteristics of the dead zone non-linear error can be accurately identified. Based on the statistical analysis of the phase deviation and dynamic segmented mapping, the adaptive adjustment of the dead zone time is realized, effectively suppressing the influence of the dead zone non-linear error on the system performance.

[0102] In one embodiment, obtaining the actual conduction state of the switching device and adjusting the dead zone time for the actual conduction state according to the dynamic compensation interval to obtain the critical safety dead zone value, including:

[0103] The conduction voltage refers to the voltage value across the switching device, and the conduction current refers to the current value flowing through the switching device. The actual conduction state of the switching device is determined based on the sampled voltage and current data, and the actual conduction state includes three states: fully conducting, partially conducting, and fully off.

[0104] Based on the actual conduction state data, combined with the voltage threshold and current threshold of the switching device, the actual switching timing of the switching device is calculated. The actual switching timing includes two key time points: the turn-on time and the turn-off time. The turn-on time refers to the time point when the switching device changes from the off state to the on state, and the turn-off time refers to the time point when the switching device changes from the on state to the off state.

[0105] The time interval between adjacent turn-on times and turn-off times in the actual switching timing is calculated to obtain the actual dead time. The actual dead time represents the time interval between two switching operations of the switching device.

[0106] The actual dead time is compared with the preset dynamic compensation interval. The dynamic compensation interval is determined by the upper limit value and the lower limit value. The upper limit value is the maximum allowable dead time, and the lower limit value is the minimum allowable dead time. The dead time deviation is calculated through comparison, and the dead time deviation represents the degree to which the actual dead time deviates from the ideal dead time.

[0107] In the actual switching timing of the switching device, the timestamps of each turn-on time and turn-off time are recorded. For any adjacent turn-on time and turn-off time, the difference between the two timestamps is calculated, and this time difference is the actual dead time. The timestamps use microsecond-level precision to ensure the accuracy of the calculation results.

[0108] The comparison calculation process of the dynamic compensation interval is described as follows:

[0109] The upper limit value and the lower limit value of the dynamic compensation interval are determined by the physical characteristics of the switching device and system requirements. The ideal dead time is set as the middle value of the dynamic compensation interval. The difference between the actual dead time and the ideal dead time is calculated, and the resulting value is the dead time deviation. When the actual dead time is greater than the ideal dead time, the deviation is positive; when the actual dead time is less than the ideal dead time, the deviation is negative.

[0110] Specific calculation example: Assume that the upper limit value of the dynamic compensation interval is 5 microseconds and the lower limit value is 1 microsecond, then the ideal dead time is 3 microseconds. When the measured actual dead time is 4 microseconds, the dead time deviation is 1 microsecond; when the measured actual dead time is 2 microseconds, the dead time deviation is -1 microsecond.

[0111] Among them, the calculation formula for the dead time deviation is:

[0112] ;

[0113] Indicates the dead time deviation, in microseconds; Indicates the actually measured dead time, in microseconds; Indicates the ideal dead time, in microseconds; Indicates the upper limit value of the dynamic compensation interval, in microseconds; Indicates the lower limit value of the dynamic compensation interval, in microseconds.

[0114] Actual dead time The calculation formula is:

[0115] ;

[0116] Indicates the timestamp at the turn-off moment, in microseconds; Indicates the timestamp at the turn-on moment, in microseconds.

[0117] Calculate the time difference compensation coefficient according to the voltage change rate and current change rate of the switching device. The turn-on delay compensation coefficient is used to compensate for the turn-on delay time of the switching device from off to on, and the turn-off delay compensation coefficient is used to compensate for the turn-off delay time of the switching device from on to off. Multiply these two compensation coefficients by the dead time deviation to obtain the compensated dead time. The compensated dead time is the dead time value after dynamic compensation.

[0118] Perform a safety margin check on the compensated dead time. The safety margin check includes a minimum dead time check and a maximum dead time check. The minimum dead time check ensures that the compensated dead time is not less than the minimum dead time required for the safe operation of the switching device, and the maximum dead time check ensures that the compensated dead time does not exceed the maximum dead time allowed by the system. The compensated dead time after passing the safety margin check is the critical safety dead time value. The critical safety dead time value not only meets the safe operation requirements of the switching device but also can suppress the dead time nonlinear error to the greatest extent.

[0119] In this embodiment, the on - state voltage and on - state current of the switching device are collected in real - time for state monitoring. By combining the dynamic compensation interval to adjust the dead - time of the actual on - state, the actual working state of the switching device can be accurately obtained, effectively avoiding the non - linear error caused by the traditional fixed dead - time method. Through the calculation of the time interval and dynamic compensation of the actual switching timing, the precise control of the dead - time is realized, significantly improving the control accuracy of pulse - width modulation. The on - delay compensation coefficient and off - delay compensation coefficient are used to compensate the dead - time deviation, effectively overcoming the delay characteristics of the switching device during the on - and off - processes. Through the safety margin verification, it is ensured that the compensated dead - time is always within the safe operating range, which not only guarantees the reliable operation of the switching device but also maximally suppresses the dead - time non - linear error, improving the overall performance and stability of the system.

[0120] In one embodiment, the duty - cycle is corrected based on the critical safety dead - time value and the dynamic compensation interval to obtain the directional compensation amount, including:

[0121] When sampling the critical safety dead - time value, the sampling frequency is set to 100 kHz, the sampling accuracy is 12 bits, and the sampling time window is 1 ms. Through the synchronous triggering method, the voltage and current signals are synchronously collected at the starting point of each switching cycle of the PWM waveform. The sampling of the dynamic compensation interval is carried out synchronously with the sampling of the critical safety dead - time value. The sampled data is converted by analog - to - digital conversion and stored in the data buffer to form a dead - time compensation sampling sequence. This sequence contains 1000 sampling points, and each sampling point contains voltage value and timestamp information.

[0122] The PWM waveform transformation process of the dead - time compensation sampling sequence: The dead - time compensation sampling sequence is processed by 1024 - point FFT transformation. The Hanning window function is used to reduce the spectral leakage, and the transformation resolution is 0.1 Hz. The obtained frequency - domain waveform characteristic data after transformation contains the amplitude spectrum and the phase spectrum, and the frequency range covers 0 - 50 kHz.

[0123] The harmonic component extraction process of the frequency - domain waveform characteristic data: The harmonic analysis algorithm is used to extract the fundamental component and the 2nd - 10th harmonic components from the frequency - domain data. The fundamental component extraction uses a band - pass filter with the center frequency set to the switching frequency and the bandwidth of 100 Hz. The high - order harmonic component extraction uses a multiple - band - pass filter bank, and the center frequency of each filter corresponds to the frequency of each harmonic, and the bandwidth increases with the increase of the harmonic order.

[0124] The PWM waveform phase correction process: Based on the extracted fundamental component and high - order harmonic components, a phase error model is established. The model uses the least - squares method to calculate the phase offset amount, the number of iterative calculations is set to 50 times, and the convergence threshold is 0.01 degrees. The calculated phase compensation coefficient is in radians and ranges from - π to π.

[0125] Nonlinear correction mapping process of phase compensation coefficient: Establish a piecewise linear interpolation function to map the phase compensation coefficient to the duty cycle correction amount. The interpolation function is divided into 5 segments, each with a different slope, and the slope value is determined according to the nonlinear characteristics of the dead zone effect. The mapped duty cycle correction amount is expressed as a percentage and ranges from -5% to 5%.

[0126] PWM waveform compensation process: Convert the duty cycle correction amount into a time-domain compensation signal, and the amplitude of the compensation signal is proportional to the switching period of the PWM waveform. Apply the compensation signal at the rising edge and falling edge of the PWM waveform respectively, and the compensation method is time-delay modulation to obtain the initial compensation amount.

[0127] Waveform direction filtering process: Design a low-pass filter with a cut-off frequency of 1 / 10 of the switching frequency and a roll-off rate of 40 dB / decade. The filter adopts Butterworth characteristics to ensure the flatness of the passband. The filtered signal retains the directional characteristics of the waveform, and finally obtains the directional compensation amount.

[0128] In this embodiment, by performing high-precision sequential sampling on the critical safety dead zone value and the dynamic compensation interval, combined with FFT transformation and harmonic analysis, the dead zone effect of the PWM waveform is accurately captured and quantified, effectively improving the accuracy of dead zone characteristic analysis. The use of the phase error model and piecewise linear interpolation mapping makes the dead zone compensation more targeted and significantly reduces the nonlinear distortion in PWM modulation. By applying time-delay compensation at the rising edge and falling edge of the PWM waveform respectively, combined with the directional filtering with Butterworth characteristics, not only the real-time nature of the compensation is ensured, but also the high-frequency interference is effectively suppressed, enabling the system to maintain a stable and reliable compensation effect under high-frequency switching operating conditions.

[0129] In one embodiment, the directional compensation amount and the initial configuration parameters are tested and verified for waveform harmonic distortion and dynamic response to obtain the dead zone compensation control strategy, including:

[0130] Set the sampling frequency of the output waveform to 100 times the switching frequency, and the sampling time span covers 50 complete cycles. The sampled data passes through the digital signal processing unit, and the DC component, fundamental component, and 2nd to 20th harmonic components are decomposed through Fourier transform. Calculate the ratio of the amplitude of each harmonic to the amplitude of the fundamental wave, and substitute the obtained data into the total harmonic distortion rate calculation model. The harmonic distortion evaluation data is output in the form of a numerical report, including the fundamental wave amplitude, the amplitude of each harmonic, the phase angle, and the total harmonic distortion rate.

[0131] In the dynamic response characteristic analysis stage, tests are carried out in open-loop and closed-loop working modes respectively. In the open-loop test, step signals with amplitudes of 20%, 50%, and 80% of the rated value are used as inputs, and the output response curves are recorded. In the closed-loop test, a sine sweep signal is used, and the frequency range covers 0.1 Hz to 1 kHz. The amplitude-frequency characteristic and phase-frequency characteristic are recorded. The dynamic response analysis module extracts the characteristic points of the response curve, calculates time-domain indexes such as rise time, peak time, settling time, overshoot, etc., and obtains frequency-domain indexes such as bandwidth, cut-off frequency, resonance peak, etc. through frequency-domain analysis. The dynamic response performance evaluation results present various performance indexes in the form of charts.

[0132] In the strategy construction stage, the mapping relationship between compensation parameters and performance indexes is established. The compensation parameters include the estimated value of dead zone width, compensation gain coefficient, non-linear function form parameters, etc. The performance indexes include key indexes such as total harmonic distortion rate, bandwidth, phase margin, etc. The optimization algorithm takes the weighted sum of performance indexes as the objective function, and searches for the optimal parameter combination through iterative calculation. The initial dead zone compensation strategy includes the analytical formula of the compensation function and the corresponding parameter values, and sets the parameter adjustment range and constraint conditions.

[0133] In the simulation verification stage, a complete simulation test platform is built. The simulation model includes a power electronic converter module, a controller module, a load module, etc. The test conditions cover operating states such as no-load, rated load, overload, etc., and the input signals include various waveforms such as DC, sine wave, square wave, etc. The simulation process records data such as the conduction state of switching devices, output voltage and current waveforms, control signals, etc. The dead zone simulation verification results include waveform diagrams, performance index data tables, and analysis reports.

[0134] In the parameter correction stage, the simulation results are compared with the design indexes. The adaptive algorithm is used in the correction process, and the parameter correction step size is dynamically adjusted according to the magnitude of the performance deviation. The parameter correction follows the principle of stability first to ensure stable operation within the full operating conditions range. The dead zone compensation control strategy is corrected and optimized through multiple rounds, and finally a complete technical solution including compensation algorithms, parameter configuration, and usage instructions is formed.

[0135] In this embodiment, through the systematic evaluation of harmonic distortion degree and dynamic response characteristic analysis of the directional compensation amount, the accurate quantification of the dead zone non-linear error of the pulse width modulation system is realized, providing reliable data support for the formulation of compensation strategies. The dead zone compensation strategy constructed based on the multi-objective optimization method effectively balances the harmonic distortion degree and dynamic response performance of the system, and significantly improves the overall control accuracy of the system. The open-loop and closed-loop dual-mode test method is adopted to comprehensively evaluate the dynamic characteristics of the system under different working conditions, ensuring the adaptability and robustness of the compensation strategy. Through the simulation verification and parameter adaptive correction mechanism, the reliability and stability of the dead zone compensation control strategy in practical applications are ensured.

[0136] In one embodiment, a harmonic distortion degree quantitative evaluation calculation is performed on the directional compensation amount to obtain harmonic distortion evaluation data, including:

[0137] During the harmonic distortion degree quantitative evaluation calculation of the directional compensation amount, the directional compensation amount refers to the compensation signal applied to suppress the dead-time non-linear error during the pulse width modulation process. This compensation signal corrects the voltage in the dead-time region to reduce the distortion of the output waveform.

[0138] In the component separation stage, the discrete Fourier transform is used to perform frequency-domain decomposition on the directional compensation amount. During the decomposition process, the time-domain signal is converted into a frequency-domain representation, and the fundamental wave amplitude and the amplitudes of each harmonic are extracted. The fundamental wave amplitude reflects the main frequency component of the signal, and the amplitudes of each harmonic characterize the high-frequency components in the signal. The separation process is achieved through signal sampling, windowing processing, and spectrum analysis.

[0139] In the harmonic statistics stage, the fundamental wave amplitude and the amplitudes of each harmonic are sorted and organized to generate a harmonic amplitude sequence. The statistical process includes the identification, extraction, and sorting of the amplitudes of each harmonic. The harmonic amplitude sequence contains the complete amplitude information from the fundamental wave to the high-order harmonics, reflecting the spectral characteristics of the signal.

[0140] In the calculation stage of the harmonic content of each order, the total harmonic distortion degree is calculated based on the harmonic amplitude sequence. The calculation process involves the comparative analysis of the amplitudes of each harmonic and the fundamental wave amplitude, and the obtained total harmonic distortion degree reflects the overall distortion level of the signal.

[0141] In the distribution analysis stage, statistical processing is performed on the total harmonic distortion degree, and the distribution of different distortion degree values is recorded to form harmonic distribution data. The analysis process includes the interval division of the distortion degree values, frequency statistics, and extraction of distribution characteristics.

[0142] In the function construction stage, the harmonic distribution density function is established by using the harmonic distribution data and adopting a Gaussian mixture model. The construction process includes data smoothing processing, curve fitting, and normalization processing. The obtained function describes the probability distribution law of the distortion degree values.

[0143] Among them, the harmonic distribution density function is:

[0144] ;

[0145] x represents the total harmonic distortion degree value; n represents the number of Gaussian components; represents the weight coefficient of the i-th Gaussian component; represents the mean value of the i-th Gaussian component; represents the standard deviation of the i-th Gaussian component

[0146] During the distortion index operation stage, numerical integration is performed on the harmonic distribution density function to obtain the cumulative harmonic distortion index. The operation process includes the determination of the integration interval, the implementation of numerical integration, and the standardization processing of the index.

[0147] In the stage of quantitative evaluation of harmonic distortion degree, the cumulative harmonic distortion index is compared with the preset evaluation criteria to obtain the harmonic distortion evaluation data. The evaluation process includes index grading, level division, and determination of the evaluation result. The evaluation data reflects the quality of the compensation effect.

[0148] In this embodiment, by quantitatively evaluating the harmonic distortion degree of the directional compensation amount, a systematic evaluation method is established, and the accurate quantification of the compensation effect is realized. The discrete Fourier transform is used for component separation to accurately extract the fundamental wave and harmonic information, providing a reliable data basis for subsequent analysis. By constructing a harmonic distribution density function based on the Gaussian mixture model, the distribution characteristics of the total harmonic distortion degree are effectively described, making the evaluation result more objective and accurate. This method can not only quantitatively characterize the harmonic distortion degree but also reflect the overall harmonic distortion level of the system through the cumulative harmonic distortion index, providing a scientific basis for the optimization of the compensation strategy. This evaluation method has strong versatility and can be applied to different types of pulse width modulation systems, effectively improving the evaluation accuracy and reliability of the dead-time nonlinear error suppression effect.

[0149] Refer to Figure 2 As shown, the present invention also provides a pulse width modulation dead-time nonlinear error suppression system, which is applied to the pulse width modulation dead-time nonlinear error suppression method of any one of the above, including:

[0150] An acquisition module, which is used to acquire the delay characteristic data of the switching device of the target circuit and the PWM signal parameters, and perform initialization parameter configuration to obtain the initial configuration parameters;

[0151] An analysis module, which is used to acquire the real-time current data of the target circuit, compare it with the initial configuration parameters for compensation, and obtain the dynamic compensation interval;

[0152] An association module, which is used to acquire the actual conduction state of the switching device, adjust the dead time according to the dynamic compensation interval for the actual conduction state, and obtain the critical safety dead-time value;

[0153] A processing module, which is used to correct the duty cycle based on the critical safety dead-time value and the dynamic compensation interval to obtain the directional compensation amount;

[0154] A control module, which is used to verify the waveform harmonic distortion degree and dynamic response of the directional compensation amount and the initial configuration parameters to obtain the dead-time compensation control strategy.

[0155] A pulse-width modulation dead-time nonlinear error suppression system provided by the present invention can more accurately evaluate the dead-time requirements under actual working conditions by comprehensively analyzing the delay characteristics of switching devices and PWM signal parameters and combining real-time current data for dynamic compensation. This improves the accuracy of dead-time compensation and provides a more reliable basis for system control. By compensating and comparing real-time current data with initial configuration parameters and adjusting the dead-time according to the dynamic compensation range, refined control of the conduction state of switching devices is achieved, which helps reduce switching losses and avoid overcompensation. Based on the critical safety dead-time value, the duty cycle is directionally corrected to ensure that the system can maintain good output waveform quality under different working conditions, reduce harmonic distortion, and improve the dynamic response performance of the system. By comprehensively analyzing the dead-time compensation amount and initial configuration parameters, a more reasonable compensation control strategy is formulated, and the optimal operation of the entire system is verified through waveform harmonic distortion and dynamic response tests, thus effectively suppressing the dead-time nonlinear error and improving the control accuracy of the system. At the same time, by considering the influence of current changes on switching characteristics, the dead-time compensation strategy can be flexibly adjusted according to the characteristics and requirements changes under different working conditions, making the system more adaptable to complex operating scenarios.

[0156] Referring to Figure 3 As shown, the present invention also provides a pulse-width modulation dead-time nonlinear error suppression device, including:

[0157] A memory for storing programs;

[0158] A processor for executing the program to implement each step of the pulse-width modulation dead-time nonlinear error suppression method described in any one of the above.

[0159] In this embodiment, the processor and the memory can be connected by a bus or other means. The memory may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as read-only memory, flash memory, hard disk, or solid-state drive. The processor may be a general-purpose processor, such as a central processing unit, a digital signal processor, an application-specific integrated circuit, or one or more integrated circuits configured to implement the embodiments of the present invention.

[0160] It should be noted that those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the above-described system and each module can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0161] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A method for suppressing non-linear error of pulse width modulation dead time, characterized in that Including: Obtaining the delay characteristic data and PWM signal parameters of the switching device of the target circuit, and performing initialization parameter configuration to obtain the initial configuration parameters; Obtaining the real-time current data of the target circuit, compensating and comparing it with the initial configuration parameters to obtain a dynamic compensation interval; Obtaining the actual conduction state of the switching device, and adjusting the dead time according to the dynamic compensation interval for the actual conduction state to obtain a critical safety dead time value; Performing duty cycle correction based on the critical safety dead time value and the dynamic compensation interval to obtain a directional compensation amount; Verifying the waveform harmonic distortion and dynamic response of the directional compensation amount and the initial configuration parameters to obtain a dead time compensation control strategy; The obtaining the real-time current data of the target circuit, compensating and comparing it with the initial configuration parameters to obtain a dynamic compensation interval includes: Performing Fourier transform processing on the real-time current data to obtain current spectrum component data; Performing current waveform reconstruction on the current spectrum component data to obtain reconstructed current waveform data; Performing zero-crossing detection on the reconstructed current waveform data to obtain a current zero-crossing time sequence; Comparing the switching timings of the initial configuration parameters according to the current zero-crossing time sequence to obtain phase deviation data; Performing compensation interval statistics on the phase deviation data to obtain a dead time compensation interval range; Performing dynamic segmented mapping on the initial configuration parameters according to the dead time compensation interval range to obtain a dynamic compensation interval; The obtaining the actual conduction state of the switching device, and adjusting the dead time according to the dynamic compensation interval for the actual conduction state to obtain a critical safety dead time value includes: Sampling and detecting the conduction voltage and conduction current of the switching device to obtain the actual conduction state; Calculating the turn-on and turn-off times of the switching device according to the actual conduction state to obtain the actual switching timings; Calculating the time interval of the actual switching timings to obtain the actual dead time; Performing upper and lower limit comparison calculations on the actual dead time and the dynamic compensation interval to obtain a dead time deviation amount; Calculating the time difference compensation coefficients for the actual switching timings to obtain a turn-on delay compensation coefficient and a turn-off delay compensation coefficient, and performing dead time compensation on the dead time deviation amount to obtain a compensated dead time; Performing safety margin verification on the compensated dead time to obtain a critical safety dead time value.

2. The pulse width modulation dead-time non-linear error suppression method according to claim 1, wherein The obtaining the delay characteristic data and PWM signal parameters of the switching device of the target circuit, and performing initialization parameter configuration to obtain the initial configuration parameters includes: Performing switching timing analysis on the delay characteristic data to obtain the turn-on delay time, turn-off delay time and conduction resistance value of the switching device; Performing device time analysis according to the turn-on delay time and the turn-off delay time to obtain the total delay time and the critical conduction time; Performing temperature coefficient correction on the total delay time and the critical conduction time, and performing voltage drop compensation according to the conduction resistance value to obtain corrected delay parameters; Extract the sampling window parameters of the PWM signal according to the corrected delay parameter, and obtain the PWM signal parameters including the duty cycle parameter, the frequency parameter, and the edge time parameter; Perform piecewise linear interpolation compensation calculation according to the corrected delay parameter and the PWM signal parameters to obtain the initial dead-time compensation time; Perform boundary limiting processing on the initial dead-time compensation time, and perform dynamic configuration adjustment according to the PWM signal parameters to obtain the initial configuration parameters.

3. The pulse width modulation dead time non-linear error suppression method according to claim 1, wherein The duty cycle correction based on the critical safety dead zone value and the dynamic compensation interval to obtain the directional compensation amount includes: Perform sequential sampling on the critical safety dead zone value and the dynamic compensation interval to obtain a dead-time compensation sampling sequence; Perform PWM waveform transformation on the dead-time compensation sampling sequence to obtain frequency-domain waveform characteristic data; Extract the harmonic components from the frequency-domain waveform characteristic data to obtain the fundamental component and the high-order harmonic components; Perform PWM waveform phase correction according to the fundamental component and the high-order harmonic components to obtain the phase compensation coefficient; Perform non-linear correction mapping on the phase compensation coefficient to obtain the duty cycle correction amount; Perform PWM waveform compensation according to the duty cycle correction amount to obtain the initial compensation amount; Perform waveform direction filtering on the initial compensation amount to obtain the directional compensation amount.

4. The pulse width modulation dead time non-linear error suppression method according to claim 1, characterized in that The waveform harmonic distortion and dynamic response test verification of the directional compensation amount and the initial configuration parameter to obtain the dead-time compensation control strategy includes: Perform quantitative evaluation calculation of the harmonic distortion of the directional compensation amount to obtain harmonic distortion evaluation data; Perform dynamic response characteristic analysis on the directional compensation amount to obtain the dynamic response performance evaluation result; Construct a strategy for the initial configuration parameter based on the harmonic distortion evaluation data and the dynamic response performance evaluation to obtain the initial dead-time compensation strategy; Perform simulation verification on the initial dead-time compensation strategy to obtain the dead-time simulation verification result; Perform parameter correction on the initial dead-time compensation strategy according to the dead-time simulation verification result to obtain the dead-time compensation control strategy.

5. The pulse width modulation dead-time non-linear error suppression method according to claim 4, characterized in that, The quantitative evaluation calculation of the harmonic distortion of the directional compensation amount to obtain the harmonic distortion evaluation data includes: Separate the components of the directional compensation amount to obtain the fundamental wave amplitude and the amplitudes of each harmonic; Perform harmonic statistics on the fundamental wave amplitude and the amplitudes of each harmonic to obtain a harmonic amplitude sequence; Calculate the content of each harmonic in the harmonic amplitude sequence to obtain the total harmonic distortion; Perform distribution analysis on the total harmonic distortion to obtain harmonic distribution data; Construct a function according to the harmonic distribution data to obtain the harmonic distribution density function; Perform distortion index operation on the harmonic distribution density function to obtain the cumulative harmonic distortion index; Perform quantitative evaluation of the harmonic distortion degree according to the cumulative harmonic distortion index to obtain the harmonic distortion evaluation data.

6. A pulse width modulation dead-time non-linear error suppression system, characterized in that, Applied to the pulse width modulation dead-time non-linear error suppression method according to any one of the above claims 1-5, including: Acquisition module, which is used to obtain the delay characteristic data and PWM signal parameters of the switching device of the target circuit, and perform initial parameter configuration to obtain the initial configuration parameters; Analysis module, which is used to obtain the real-time current data of the target circuit, perform compensation comparison with the initial configuration parameters to obtain the dynamic compensation interval; Association module, which is used to obtain the actual conduction state of the switching device, and adjust the dead time of the actual conduction state according to the dynamic compensation interval to obtain the critical safety dead time value; Processing module, which is used to perform duty cycle correction based on the critical safety dead time value and the dynamic compensation interval to obtain the directional compensation amount; Control module, which is used to perform waveform harmonic distortion and dynamic response test verification on the directional compensation amount and the initial configuration parameters to obtain the dead time compensation control strategy; The obtaining of the real-time current data of the target circuit, performing compensation comparison with the initial configuration parameters to obtain the dynamic compensation interval includes: Performing Fourier transform processing on the real-time current data to obtain current spectrum component data; Performing current waveform reconstruction on the current spectrum component data to obtain reconstructed current waveform data; Performing zero-crossing detection on the reconstructed current waveform data to obtain the current zero-crossing moment sequence; Performing switching timing comparison on the initial configuration parameters according to the current zero-crossing moment sequence to obtain phase deviation data; Performing compensation interval statistics on the phase deviation data to obtain the dead time compensation interval range; Performing dynamic segmented mapping on the initial configuration parameters according to the dead time compensation interval range to obtain the dynamic compensation interval; The obtaining of the actual conduction state of the switching device, adjusting the dead time of the actual conduction state according to the dynamic compensation interval to obtain the critical safety dead time value includes: Sampling and detecting the conduction voltage and conduction current of the switching device to obtain the actual conduction state; Calculating the turn-on and turn-off moments of the switching device according to the actual conduction state to obtain the actual switching timing; Calculating the time interval of the actual switching timing to obtain the actual dead time; Performing upper and lower limit comparison calculation on the actual dead time and the dynamic compensation interval to obtain the dead time deviation amount; Calculating the time difference compensation coefficient of the actual switching timing to obtain the turn-on delay compensation coefficient and the turn-off delay compensation coefficient, and performing dead time compensation on the dead time deviation amount to obtain the compensated dead time; Performing safety margin verification on the compensated dead time to obtain the critical safety dead time value.

7. A pulse width modulation dead time non-linear error suppression device, characterized in that, Includes: Memory, which is used to store programs; Processor, which is used to execute the program to implement each step of a method for suppressing the non-linear error of the pulse width modulation dead time as described in any one of claims 1-5.

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