Capacitor loss angle determination method and device, storage medium and computer equipment

Abstract

The invention discloses a capacitor loss angle determination method and device, a storage medium and computer equipment, and the method comprises the steps: carrying out the coarse frequency scanning of a measurement loop based on a logarithmic frequency step length, and determining a resonance region based on the change rate of the impedance amplitude of the measurement loop; performing fine frequency scanning on the measurement loop based on the linear frequency step length in the resonance area; determining a resonance peak based on the impedance amplitude of a frequency point in the resonance area; determining resonance attribute information of the resonance peak; selecting a reference frequency point in a preset area around the resonance peak based on the resonance attribute information; determining an initial resonance point frequency of the measurement loop, and compensating the initial resonance point frequency to obtain a resonance point frequency; determining a resonance type and a corresponding loss angle determination mode, determining initial circuit parameters, and performing error compensation on the initial circuit parameters in real time to obtain circuit parameters; and based on the circuit parameters and the resonance point frequency, determining the capacitor loss angle by using a loss angle determination mode.

Description

Technical Field

[0001] This invention relates to the field of capacitor parameter measurement technology, and in particular to a method, apparatus, storage medium, and computer device for determining the capacitor loss angle. Background Art

[0002] With the rapid development of power electronics and new energy technologies, capacitors, as important energy storage and filtering components, are playing an increasingly vital role in power systems, new energy vehicles, rail transportation, aerospace, and other fields. The loss angle of a capacitor is a key parameter for evaluating its performance, directly affecting system efficiency, temperature rise characteristics, service life, and reliability. Therefore, measuring the loss angle of capacitors has significant engineering implications.

[0003] Currently, a fixed step size is typically used to perform a uniform frequency scan of the circuit, and the capacitor loss angle is directly determined based on the scan results. However, this fixed step size frequency scan is prone to missing the true resonant point due to an excessively large scan step size, or taking too long to scan due to an excessively small scan step size, resulting in low efficiency and low accuracy in determining the capacitor loss angle. Summary of the Invention

[0004] This invention provides a method, apparatus, storage medium, and computer equipment for determining the loss angle of a capacitor, which mainly improves the efficiency and accuracy of determining the loss angle of a capacitor.

[0005] According to a first aspect of the present invention, a method for determining the loss angle of a capacitor is provided, applied to a measurement circuit consisting of a signal generator, a capacitor under test, and an inductor, comprising:

[0006] In response to the loss angle determination signal of the capacitor under test, a coarse frequency scan is performed on the measurement circuit through the signal generator based on a logarithmic frequency step. During the coarse frequency scan, the resonant region of the capacitor under test is determined based on the rate of change of the impedance amplitude of the measurement circuit.

[0007] Within the resonant region, a fine frequency scan is performed on the measurement circuit via the signal generator based on a linear frequency step. During the fine frequency scan, the resonant peak is determined based on the impedance amplitude at each frequency point in the resonant region, and the resonant attribute information of the resonant peak is determined, wherein the resonant attribute information is the position and width of the resonant peak.

[0008] Based on the resonance attribute information, a reference frequency point is selected in a preset area around the resonance peak, and the initial resonance point frequency of the measurement circuit is determined based on the impedance value corresponding to the reference frequency point. The initial resonance point frequency is then compensated to obtain the resonance point frequency.

[0009] The resonance type of the measurement circuit is determined, the loss angle determination method of the capacitor under test is determined based on the resonance type, the initial circuit parameters of the measurement circuit are determined, and the initial circuit parameters are compensated for errors in real time to obtain the circuit parameters.

[0010] Based on the circuit parameters and the resonant frequency, the loss angle of the capacitor under test is determined using the loss angle determination method.

[0011] According to a second aspect of the present invention, a device for determining the loss angle of a capacitor is provided, applied to a measurement circuit consisting of a signal generator, a capacitor under test, and an inductor, comprising:

[0012] A coarse frequency scanning unit is used to respond to the loss angle determination signal of the capacitor under test, and to perform a coarse frequency scan on the measurement circuit through the signal generator based on a logarithmic frequency step. During the coarse frequency scan, the resonant region of the capacitor under test is determined based on the rate of change of the impedance amplitude of the measurement circuit.

[0013] A fine-frequency scanning unit is used to perform fine-frequency scanning in the resonant region by means of the signal generator to the measurement circuit based on a linear frequency step. During the fine-frequency scanning process, the resonant peak is determined based on the impedance amplitude of each frequency point in the resonant region, and the resonant attribute information of the resonant peak is determined, wherein the resonant attribute information is the position and width of the resonant peak.

[0014] The frequency determination unit is used to select a reference frequency point in a preset area around the resonance peak based on the resonance attribute information, and determine the initial resonance point frequency of the measurement circuit based on the impedance value corresponding to the reference frequency point, and compensate the initial resonance point frequency to obtain the resonance point frequency.

[0015] The compensation unit is used to determine the resonance type of the measurement circuit, determine the loss angle determination method of the capacitor under test based on the resonance type, determine the initial circuit parameters of the measurement circuit, and perform error compensation on the initial circuit parameters in real time to obtain the circuit parameters.

[0016] The loss angle determination unit is used to determine the loss angle of the capacitor under test based on the circuit parameters and the resonant frequency using the loss angle determination method.

[0017] According to a third aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the above-described method for determining the capacitor loss angle.

[0018] According to a fourth aspect of the present invention, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-described method for determining the capacitor loss angle.

[0019] According to the present invention, a method, apparatus, storage medium, and computer device for determining the loss angle of a capacitor are provided. Compared with the current method of performing a uniform frequency scan of the circuit with a fixed step size and directly determining the loss angle of the capacitor based on the scan results, the present invention first performs a coarse frequency scan of the measurement circuit with a logarithmic frequency step size to determine the resonant region. Within the resonant region, a fine frequency scan of the measurement circuit with a linear frequency step size is performed to determine the resonant peak. Then, based on the impedance values ​​of reference frequency points around the resonant peak, the initial resonant frequency is determined and compensated to obtain the resonant frequency. After that, the resonance type is determined, and a loss angle determination method corresponding to the resonance type is used to analyze the circuit parameters and resonant frequency of the measurement circuit to obtain the loss angle of the capacitor under test. Therefore, by employing a three-level search strategy of adaptive frequency coarse scan, fine scan, and precise positioning to determine the resonant frequency, it is possible to ensure accurate scanning of the resonant point while reducing scanning time, thereby improving the efficiency and accuracy of determining the capacitor loss angle. Furthermore, by performing error compensation on the resonant frequency, the influence of measurement errors on the resonant point can be avoided, thus improving the accuracy of the resonant frequency and consequently, the accuracy of determining the capacitor loss angle. Finally, by performing real-time error compensation on the circuit parameters, the influence of the external environment on the circuit parameters can be avoided, thus ensuring the accuracy of the circuit parameters and further improving the accuracy of determining the capacitor loss angle. Attached Figure Description

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 A flowchart of a method for determining the capacitor loss angle provided by an embodiment of the present invention is shown;

[0022] Figure 2 This diagram illustrates the overall architecture of a capacitor loss angle measurement method provided by an embodiment of the present invention.

[0023] Figure 3 The diagram illustrates a hardware module architecture for determining the capacitor loss angle according to an embodiment of the present invention.

[0024] Figure 4 A schematic diagram of a resonant circuit for determining the capacitor loss angle according to an embodiment of the present invention is shown.

[0025] Figure 5 This diagram illustrates a technical architecture of a resonance measurement module provided by an embodiment of the present invention.

[0026] Figure 6 This diagram illustrates a technical architecture of a signal generation module according to an embodiment of the present invention.

[0027] Figure 7 This diagram illustrates a technical architecture of a data acquisition module according to an embodiment of the present invention.

[0028] Figure 8 This diagram illustrates a technical architecture of a control processing module provided by an embodiment of the present invention.

[0029] Figure 9 This diagram illustrates a technical architecture of a measurement circuit module according to an embodiment of the present invention.

[0030] Figure 10 This diagram illustrates a signal conditioning and interface circuit architecture provided by an embodiment of the present invention.

[0031] Figure 11 This invention provides a flow control diagram for intelligent measurement of capacitor loss angle according to an embodiment of the present invention.

[0032] Figure 12 A flowchart of another method for determining the capacitor loss angle provided by an embodiment of the present invention is shown;

[0033] Figure 13 A schematic diagram of a capacitor loss angle determination device provided in an embodiment of the present invention is shown.

[0034] Figure 14 A schematic diagram of another capacitor loss angle determination device provided in an embodiment of the present invention is shown;

[0035] Figure 15 A schematic diagram of the physical structure of a computer device provided by an embodiment of the present invention is shown. Detailed Implementation

[0036] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the present application can be combined with each other.

[0037] Currently, the method of performing a uniform frequency scan on the circuit using a fixed step size and directly determining the capacitor loss angle based on the scan results is prone to missing the true resonant point due to an excessively large scan step size, or taking too long to scan due to an excessively small scan step size. This results in low efficiency and low accuracy in determining the capacitor loss angle.

[0038] To address the above problems, embodiments of the present invention provide a method for determining the capacitor loss angle, such as... Figure 1 As shown, the method includes:

[0039] 101. Applied to a measurement circuit consisting of a signal generator, a capacitor under test, and an inductor, it responds to the loss angle of the capacitor under test to determine the signal, and performs a coarse frequency scan of the measurement circuit through the signal generator based on a logarithmic frequency step. During the coarse frequency scan, the resonant region of the capacitor under test is determined based on the rate of change of the impedance amplitude of the measurement circuit.

[0040] Specifically, if Figure 2 As shown, the overall architecture of the capacitor loss angle measurement method in this embodiment of the invention includes a signal generation module, a resonance measurement module (resonance measurement circuit), a data acquisition module, and a control processing module (intelligent control unit, calibration reference module, and data processing unit). The architecture diagram of each module (hardware module) is shown below. Figure 3 As shown, the measurement circuit (resonant circuit) is as follows: Figure 4 As shown in the diagram, the technical architecture of the resonance measurement module is as follows: Figure 5 As shown, the technical architecture diagram of the signal generation module is as follows: Figure 6 As shown in the diagram, the technical architecture of the data acquisition module is as follows: Figure 7 As shown, the technical architecture diagram of the control processing module is as follows: Figure 8 As shown. The overall architecture adopts a distributed design concept, with each module connected via a high-speed digital bus, supporting efficient data exchange and collaborative operation between modules. The signal generation module uses a high-precision signal generator; for example, the signal generator can be based on a 32-bit phase accumulator and a 14-bit DAC (Digital-to-Analog Converter). Low-distortion sine wave output is achieved through multi-stage filtering and feedback control, with a total harmonic distortion (THD) < -80dB and a spurious-free dynamic range (SFDR) > 70dBc. Programmable output amplitude control uses a combination of a high-precision digitally controlled attenuator and a variable gain amplifier, with an amplitude range of 10mV-10V. The signal generator also integrates amplitude and phase modulation functions, supporting multiple operating modes such as frequency sweep, frequency modulation, and frequency hopping. The output impedance matching circuit uses a broadband transformer and a balun to unbalanced converter to ensure impedance matching across the entire frequency range.

[0041] The resonant measurement module includes a high-precision air-core inductor using a multi-layer winding process. The low-loss test fixture uses insulating materials and gold-plated conductors, and all parasitic parameters are precisely calibrated. Multi-range current detection employs a combination of Hall effect sensors and precision shunts. The test fixture also integrates open-circuit / short-circuit / load calibration components, supporting rapid calibration.

[0042] The data acquisition module is equipped with a 24-bit Sigma-Delta ADC (Σ-Δ analog-to-digital converter). The differential input design utilizes an instrumentation amplifier and an active filter. Synchronous sampling is achieved through a phase-locked loop and a high-precision clock distribution system. The data acquisition module also integrates a programmable gain amplifier. The anti-aliasing filter employs an 8th-order Butterworth filter with a programmable cutoff frequency.

[0043] The control and processing module uses a high-performance processor, integrating a floating-point unit and a DSP coprocessor. It features a large-capacity memory to support complex algorithm implementation and large-scale data storage. A multi-interface design supports various communication interfaces such as Gigabit Ethernet, USB 3.0, RS-232, and RS-485, facilitating system integration and remote control. The real-time operating system uses embedded Linux, supporting multi-tasking parallel processing and real-time response.

[0044] Precision measurement circuits (measurement loops) are crucial for achieving high-precision measurements. These circuits consist of a signal generator, the capacitor under test, and an inductor. For example, ... Figure 9 The circuit shown features a low-noise front-end design employing an ultra-low-noise chopper-stabilized amplifier, with input voltage noise density less than [value missing] and input current noise density less than [value missing] set according to actual requirements. The amplifier utilizes dynamic bias technology, eliminating 1 / f noise and bias voltage by periodically swapping the input terminals and reversing the signal polarity. The precision resistor network uses high-precision resistors manufactured using thin-film technology, with resistance accuracy better than 0.01%, temperature coefficient less than 2ppm / ℃, and long-term stability better than 5ppm / year. Active protection circuitry includes overvoltage protection, overcurrent protection, and electrostatic discharge protection, with programmable protection thresholds and a response time less than 1μs. The precision reference circuit includes a temperature-compensated reference source, employing a combination of a bandgap reference and a temperature sensor, with an output voltage temperature coefficient less than 1ppm / ℃ and long-term stability better than 2ppm / 1000 hours. The high-precision reference capacitor uses an air-dielectric variable capacitor, with capacitance value precisely adjustable within the range of 10pF-1000pF, accuracy 0.01%, and a temperature coefficient less than 10ppm / ℃. The real-time calibration circuit integrates multiple calibration references, including voltage, current, and impedance references, supporting automatic periodic calibration. Signal conditioning and interface circuitry: The signal conditioning circuitry is responsible for converting the measured signal into a standard signal suitable for ADC sampling, and the interface circuitry enables reliable connection to external devices. For example, ... Figure 10As shown, the programmable gain amplifier employs a precision instrumentation amplifier and a relay-switched resistor network, achieving a gain setting accuracy better than 0.01%, gain linearity better than 0.001%, and a gain temperature coefficient less than 5ppm / ℃. The amplifier bandwidth remains at 10MHz even at maximum gain, with a slew rate greater than 1000V / μs, ensuring faithful amplification of fast signals. Gain control uses a digital interface, supporting programmable gain setting and automatic sizing. The programmable filter uses a combination of switched-capacitor filters and continuous-time filters, with filter types including low-pass, high-pass, band-pass, and band-stop, and a cutoff frequency that can be programmably set within the 1Hz-1MHz range. The filter design employs a multi-order structure, with single-order filters reaching up to 8th order, and multiple filters can be cascaded. Filter parameters, including cutoff frequency, quality factor, and gain, are independently adjustable. The signal isolation circuit combines transformer coupling and opto-isolation, with isolation voltage and impedance both exceeding the values ​​set according to actual requirements. Analog signal isolation uses linear optocouplers, achieving linearity better than 0.01% and a bandwidth greater than 10MHz. Digital signal isolation utilizes magnetic couplers, achieving data transmission rates of up to 100Mbps with a transmission delay of less than 10ns. The interface protection circuitry includes multi-level protection such as transient voltage suppressors, gas discharge tubes, and varistors, capable of withstanding 4kV electrostatic discharge and 2kV electrical fast transient / burst damage. The interface circuitry also integrates open / short circuit detection, automatically identifying the connection status of the test lines.

[0045] Furthermore, in terms of measurement process control algorithms, for example, such as Figure 11The measurement process control algorithm shown realizes an automated, high-precision measurement process. The algorithm employs a state machine design, including multiple working states such as initialization, calibration, measurement, data processing, and result output. Switching between states is event-driven. The initialization phase includes a hardware self-test program, which verifies the working status of each hardware module through built-in self-test functions, including the frequency accuracy of the signal generator, the gain accuracy of the amplifier, and the quantization accuracy of the ADC. The environmental parameter monitoring program reads environmental parameters such as temperature, humidity, and atmospheric pressure in real time, establishing an environmental parameter database. The measurement parameter setting program automatically optimizes the excitation frequency, signal amplitude, measurement time, and filtering parameters according to the type of capacitor being measured and the measurement requirements. Parameter optimization uses a machine learning algorithm, which can predict the optimal parameter settings based on historical measurement data. The adaptive frequency scanning program in the measurement execution phase dynamically adjusts the scanning step size and measurement time according to the preset frequency range and accuracy requirements. The scanning algorithm uses a strategy combining the golden section method and the bisection method, improving search efficiency while ensuring search completeness. The resonant point identification program uses multiple criteria, including impedance maximum / minimum detection, phase zero-point detection, and energy peak detection, to ensure the accuracy of resonant point identification. The quality factor extraction program employs a nonlinear fitting algorithm, supporting various circuit models, including a simple RLC model (a combined model of resistance, inductance, and capacitance), a corrected model incorporating parasitic parameters, and a frequency-dependent parameter model. The real-time error compensation program dynamically adjusts compensation parameters based on environmental conditions and system status to ensure measurement accuracy. The results processing stage includes a data validity verification program, which verifies the reliability of measurement data through physical consistency checks, statistical consistency checks, and historical data comparisons. The outlier handling program identifies and marks suspicious data, employing robust statistical methods to handle outliers. The uncertainty calculation program calculates combined and expanded uncertainties based on uncertainty propagation theory. The results output program supports multiple data formats, including standard measurement report formats, database formats, and graphical report formats. Data processing and analysis algorithms: Data processing algorithms are crucial for ensuring measurement accuracy; the algorithm design fully considers noise suppression, baseline correction, parameter extraction, and other aspects. The signal preprocessing module employs a multi-stage digital filtering structure, including pre-filtering, anti-aliasing filtering, and bandpass filtering. Pre-filtering employs median filtering and morphological filtering to remove impulse noise and transient interference. Anti-aliasing filtering uses digital resampling technology to prevent spectral aliasing. Bandpass filtering uses a cascaded array of filters: one for steep frequency selectivity and another for linear phase characteristics. Noise suppression uses an adaptive Wiener filtering algorithm, dynamically adjusting filter parameters based on the statistical properties of the signal and noise. The algorithm also integrates wavelet denoising technology, removing noise components through wavelet decomposition and reconstruction.Baseline correction employs a combination of polynomial fitting and spline interpolation to handle various types of baseline drift. The parameter extraction module utilizes an improved Levenberg-Marquardt nonlinear fitting algorithm, combined with a genetic algorithm for global optimization. The fitting algorithm supports various circuit models, including ideal RLC models, modified models considering parasitic parameters, and complex frequency-dependent models. To improve fitting accuracy, the algorithm uses weighted least squares, allocating weights based on measurement uncertainty. A multi-starting-point strategy is employed during the fitting process to avoid getting trapped in local optima. The algorithm also integrates physical constraints on the parameters to ensure the physical reasonableness of the fitting results. Convergence judgment uses a multi-criteria method, including multiple indicators such as parameter change rate, fitting residual, and gradient magnitude. The result verification module includes multiple verification mechanisms to ensure the reliability of the measurement results. Physical reasonableness checks verify whether parameter values ​​are within reasonable ranges, such as whether the quality factor is positive and whether the resonant frequency is within the measurement range. Statistical consistency checks evaluate the reproducibility and stability of measurements through statistical analysis of repeated measurements. Historical data comparison analysis compares current measurement results with historical data to identify possible systematic changes. The algorithm also integrates anomaly detection, capable of identifying abnormal measurement results caused by equipment malfunctions or external interference. Adaptive control and optimization algorithms: To achieve optimal performance under different measurement conditions, the system integrates multiple adaptive control and optimization algorithms. The measurement parameter optimization algorithm automatically adjusts excitation signal parameters, measurement time, filter settings, etc., based on the characteristics of the measured capacitor and measurement requirements. The optimization objective is to minimize measurement time while ensuring measurement accuracy. The algorithm employs a multi-objective optimization method, establishing a Pareto front for accuracy-time and selecting the optimal solution based on user priorities. Parameter optimization also considers the dynamic characteristics of the system, dynamically adjusting parameter settings through adaptive control theory. The environmental adaptability algorithm monitors changes in environmental conditions and automatically adjusts system operating parameters to maintain optimal performance. The temperature compensation algorithm dynamically adjusts calibration parameters and compensation factors based on real-time temperature measurements. The humidity compensation algorithm considers the impact of humidity on insulating materials and the dielectric constant of capacitors. The electromagnetic interference adaptation algorithm dynamically adjusts filter parameters and measurement strategies based on the intensity and spectral distribution of environmental electromagnetic interference. The learning optimization algorithm possesses machine learning capabilities, continuously improving algorithm performance based on historical measurement data. The algorithm uses a neural network model to learn the patterns of measurement errors and establish error prediction and compensation models. Support Vector Machine (SVM) algorithms are used for anomaly detection and fault diagnosis. Reinforcement learning algorithms are used to optimize measurement strategies, finding the optimal measurement sequence through trial and error. Experimental verification and performance evaluation: Standard capacitor verification testing: To comprehensively verify the performance of the capacitor loss angle measurement system, various types of standard capacitors were used for testing and verification. The test scheme covered capacitors with different capacitance values, different loss levels, and different operating frequencies, ensuring the comprehensiveness and representativeness of the verification.For example, polystyrene standard capacitor testing uses traceable standard capacitors with capacitance values ​​ranging from 100pF to 10μF, nominal accuracy of 0.01%, and loss tangent tanδ < 2×10. -4 The frequency range was 1kHz-1MHz. Tests were conducted in a constant temperature and humidity environment, for example, temperature controlled at 23±1℃ and relative humidity controlled at 45±5%. Each capacitance value was measured 10 times repeatedly, and the average value and standard deviation were calculated. Test results showed that the relative error of the capacitance value measurement was less than 0.005%, and the absolute error of the loss tangent was less than 1×10⁻⁶. -5 The ceramic standard capacitor testing covers capacitors with different dielectric types such as C0G, X7R, and Y5V, with capacitance values ​​ranging from 1pF to 1μF and loss tangent values ​​ranging from 10°. -3 -10 -2 The frequency range was 100kHz-10MHz. Due to the nonlinear characteristics of ceramic capacitors, small-signal excitation was used, with the excitation voltage controlled below 100mV. The effects of DC bias, temperature, and frequency on capacitor parameters were also evaluated. The results show that the system can accurately measure the frequency and temperature characteristics of ceramic capacitors. Electrolytic standard capacitor tests included aluminum electrolytic capacitors and tantalum electrolytic capacitors, with capacitance values ​​ranging from 1μF to 1000μF and loss tangent values ​​ranging from 10°. -2 -1, with a frequency range of 100Hz-100kHz. Due to the large equivalent series resistance of electrolytic capacitors, the four-terminal method was used to eliminate the influence of lead resistance. The test also evaluated parameters such as leakage current and the frequency characteristics of the equivalent series resistance. The system provides accurate and reliable measurement results throughout the entire test range. Measurement accuracy verification: The system's measurement accuracy was fully verified through comparison measurements with national standards laboratories. The comparison tests were conducted according to the comparison specifications of international metrology organizations to ensure the authority and credibility of the comparison results. The measurement accuracy verification of low-loss capacitors used a loss tangent value of 10°. -5 -10 -3 Ultra-low loss capacitors within the specified range. Experimental results confirm the system's excellent measurement stability. The distribution of measurement deviations conforms to a normal distribution, with no significant systematic bias. Measurement accuracy verification for medium loss capacitors covers loss tangent values ​​within 10°. -3 -10 -1 Capacitors within a certain range. Measuring these capacitors is relatively easy, but frequency-dependent loss mechanisms and nonlinear effects still need to be considered. Comparison results show that they meet the high-precision requirements of engineering measurements. The accuracy verification of high-loss capacitor measurements is performed for loss tangent values ​​within 10°. -1Capacitors in the -1°C range. These capacitors are commonly used in power electronics applications, and their loss mechanisms are complex, making measurement challenging. The system optimizes the excitation signal and measurement algorithm to achieve lower measurement uncertainty, providing an effective solution for the accurate measurement of high-loss capacitors. Temperature stability testing: Temperature stability is a crucial indicator for precision measuring instruments, directly affecting the reliability of long-term measurements. This system underwent comprehensive temperature stability testing to evaluate the impact of temperature changes on measurement accuracy. For example, the temperature stability test was conducted in a dedicated temperature test chamber with a temperature range of 15°C-35°C, and the temperature change rate was controlled within 1°C / hour to ensure the system could effectively track temperature changes. The test cycle was 72 consecutive hours, with measurement data recorded hourly. A high-stability standard capacitor was used as the test piece, and its measured value was monitored as a function of temperature.

[0046] Test results show that for low-loss capacitors, the system temperature coefficient is less than a certain value, such as 1×10⁻⁶. -6 / ℃, far exceeding the technical specifications. Throughout the entire temperature range, the peak-to-peak value of the measurement deviation is less than any root mean square value, meeting the requirements. The temperature compensation algorithm effectively compensates for the effects of temperature changes, further reducing the temperature coefficient to the set temperature after compensation. Long-term stability testing was conducted for an extended period, monitoring the system's long-term drift characteristics under normal operating conditions. Test results show that the system exhibits good long-term stability, meeting the long-term stability requirements for precision measurement. The main influencing factors on stability are the aging of electronic components and slow changes in environmental conditions; regular calibration effectively maintains the system's long-term stability. This tested system can then be used to measure the capacitor loss angle, ensuring accurate measurement results. The modular hardware design and standardized software interface in the overall architecture of the capacitor loss angle measurement in this embodiment facilitate industrial production and maintenance.

[0047] Specifically, the signal generator provides signals of different frequencies to the measurement loop. This invention proposes a gradient-guided intelligent resonance search algorithm, which employs a three-stage search strategy of coarse scan, fine scan, and precise positioning. The coarse scan stage uses a logarithmic frequency step size for rapid scanning (i.e., by adjusting the frequency of the signal generator), with the step size set as follows:

[0048] Δf coarse =f current ×α coarse

[0049] Where, Δf coarse f is the coarse frequency scan step size. current α is the current frequency value. coarseThe coarse scan coefficients are set according to actual needs. The scanning is performed by increasing the frequency from low frequency to high frequency. During the scanning process, the impedance amplitude change at adjacent frequency points is calculated in real time, and the peak range of the impedance amplitude change rate is determined. The resonance corresponding to this range is determined as the resonance candidate region (resonance region).

[0050] 102. Within the resonant region, a fine frequency scan is performed on the measurement circuit using a signal generator based on a linear frequency step size. During the fine frequency scan, the resonant peak is determined based on the impedance amplitude at each frequency point in the resonant region, and the resonant attribute information of the resonant peak is determined, where the resonant attribute information is the position and width of the resonant peak.

[0051] Specifically, the fine scanning stage employs a linear frequency step size scan within the identified resonant region, with the frequency formula shown below:

[0052]

[0053] Where, Δf fine f is the linear step size for the fine scan phase. max f is the maximum frequency in the resonant region. min Nf is the minimum frequency in the resonant region. fine The fine scanning point count is used to precisely determine the position and width of the resonant peak. Specifically, during the fine scanning process, scanning can be performed based on a predetermined number of fine scanning points. For example, starting from the lower limit of the resonant region, the frequency is increased with a fixed step size. Impedance data is collected three times at each frequency point, and the average value is taken. The impedance amplitude |Z| and its corresponding frequency f are recorded. Based on the impedance amplitude array, a curve is fitted using quadratic interpolation. The point with the maximum impedance in this curve is the resonant peak, and its corresponding frequency is the resonant peak frequency. The position of the point with the maximum impedance is the position of the resonant peak. The difference between the upper and lower limit frequencies corresponding to the impedance amplitude |Z| is taken as the resonant width of the resonant peak.

[0054] 103. Based on the resonance attribute information, select a reference frequency point in the preset area around the resonance peak, and determine the initial resonance frequency of the measurement circuit based on the impedance value corresponding to the reference frequency point. Then, compensate for the initial resonance frequency to obtain the resonance frequency.

[0055] Furthermore, in the precise positioning stage, a parabolic fitting method is used to accurately determine the resonant frequency, and the calculation formula is shown below:

[0056]

[0057] Where a and b are the coefficients of the fitted parabola, f resonance To pinpoint the resonant frequency after precise location, f peakThe initial frequency of the resonant peak is determined. Specifically, a preset region is defined with the resonant peak location as the center and a distance *r* selected according to actual needs as the radius. For example, multiple reference frequency points are selected at equal intervals within the preset region. The corresponding impedance amplitude (impedance value) is measured at each selected reference point, and a quadratic polynomial is used to fit the impedance amplitude corresponding to the reference frequency point. The extreme point of the fitted curve is calculated, and this extreme point is taken as the resonant point. The frequency of this extreme point is taken as the initial resonant point frequency. Furthermore, to improve the accuracy of determining the resonant point frequency, the initial resonant point frequency also needs to be calibrated and compensated. This embodiment of the invention determines the resonant point frequency through a three-level search strategy of adaptive frequency coarse scanning-fine scanning-precise positioning. This ensures accurate scanning of the resonant point while reducing scanning time, thereby improving the efficiency and accuracy of determining the capacitor loss angle. By compensating for the resonant point frequency error, the influence of measurement error on the resonant point can be avoided, thereby improving the accuracy of the resonant point frequency and, consequently, the accuracy of determining the capacitor loss angle.

[0058] 104. Determine the resonance type of the measurement circuit, determine the loss angle determination method of the capacitor under test based on the resonance type, determine the initial circuit parameters of the measurement circuit, and perform error compensation on the initial circuit parameters in real time to obtain the circuit parameters.

[0059] The resonance types include series resonance, parallel resonance, and higher-order resonance; the initial electrical parameters include capacitance, resistance, and inductance.

[0060] In this embodiment of the invention, to accurately determine the capacitor loss angle, it is first necessary to determine the resonance type of the measurement circuit. Therefore, step 104 specifically includes: during the frequency scanning process of the signal generator towards the measurement circuit, determining the impedance frequency characteristic curve and impedance phase of the measurement circuit; extracting the peak value, valley value, and rate of change of the impedance frequency characteristic curve using frequency domain features, and determining the frequency domain resonance type of the measurement circuit based on the peak value, valley value, and rate of change; analyzing the change characteristics of the impedance phase using phase domain features, and determining the phase domain resonance type of the measurement circuit based on the change characteristics; and determining the resonance type of the measurement circuit based on the frequency domain resonance type and the phase domain resonance type.

[0061] Specifically, during the frequency scanning process of the signal generator to the measurement circuit, the first-order difference of the impedance amplitude is calculated, and the extreme points of the rate of change of the impedance amplitude are identified based on the first-order difference. The point where the first-order difference changes from positive to negative is taken as the peak point, and the point where the first-order difference changes from negative to positive is taken as the valley point, and the phase change rate is determined. Frequency domain feature extraction identifies different types of resonance by analyzing the peak, valley, and rate of change of the impedance frequency characteristic curve. Series resonance corresponds to the frequency of the minimum impedance, parallel resonance corresponds to the frequency of the maximum impedance, and higher-order resonances are manifested as local extreme points of the impedance curve. Phase domain feature analysis verifies the resonance type by analyzing the phase change characteristics of the impedance. In series resonance, the phase changes from positive to negative, and the zero-crossing point corresponds to the resonant frequency; in parallel resonance, the phase changes from negative to positive, and the zero-crossing point corresponds to the resonant frequency. Resonance mode confirmation combines frequency domain and phase domain features, and a pattern recognition algorithm is used to confirm the resonance type, ensuring that the correct resonance point is selected for loss calculation.

[0062] Furthermore, in order to determine the capacitor loss angle, it is also necessary to determine the circuit parameters in the measurement loop. The circuit parameters can be measured by a measuring device or calculated using the following formula:

[0063] Z(f)=R+j[2πfL-1 / (2πfC)]

[0064] Where Z(f) is the impedance value in the measurement circuit, R is the resistance value, L is the inductance value, C is the capacitance value, f is the resonant frequency corresponding to the impedance value, and j is the impedance coefficient set according to actual needs.

[0065] Furthermore, different loss angle determination methods are used for different resonance types; that is, series resonance, parallel resonance, and high-frequency resonance each correspond to different loss angle determination methods. Finally, the determined loss angle determination method is used to determine the capacitor's loss angle. During the process of determining the capacitor's loss angle, since circuit parameters are affected by environmental factors, error compensation is needed for the initial circuit parameters to ensure the accuracy of the loss angle determination. Based on this, the method includes: acquiring a sample circuit parameter dataset, wherein the sample circuit parameter dataset includes sample circuit parameters P under different sample temperature values ​​T. T The reference circuit parameters P0 at the reference temperature T0; based on the sample circuit parameter dataset, the temperature compensation coefficients α1 and α2 of the initial circuit parameters are determined, wherein, Determine the acquisition temperature value at the time of initial circuit parameter acquisition, and compensate the initial circuit parameters based on the temperature compensation coefficients α1 and α2, the acquisition temperature value, and the reference temperature value T0, and use the compensated initial circuit parameters as the circuit parameters.

[0066] Specifically, the sample circuit parameters P under the sample temperature value T in the sample circuit parameter dataset.T Substitute the reference circuit parameter P0 at the reference temperature T0 into the formula. A system of equations containing unknowns α1 and α2 is established. Solving this system yields the temperature compensation coefficients α1 and α2. Then, the temperature value at the initial circuit parameter acquisition time is taken as T, the reference temperature value as T0, the initial circuit parameters as P0, and the temperature value as T, reference temperature value T0, initial circuit parameters P0, and temperature compensation coefficients α1 and α2 are substituted into the above formula to obtain the compensated circuit parameters. This embodiment of the invention, by performing temperature compensation on the circuit parameters, avoids the influence of temperature changes on the circuit parameters, ensuring the validity of the circuit parameters and thus improving the accuracy of determining the capacitor loss angle.

[0067] In another embodiment of the present invention, during the acquisition process of the initial circuit parameters, the nonlinear characteristics of the acquisition system will affect the consistency of large-signal and small-signal measurements. That is, the initial circuit parameters will also be affected by the signal changes in the measurement loop during the acquisition process. Therefore, it is necessary to perform nonlinear compensation on the initial circuit parameters. Based on this, the method includes: acquiring a sample signal amplitude dataset, wherein the sample signal amplitude dataset includes sample signal amplitudes A in different signal ranges and sample circuit parameters G(A) under the sample signal amplitude A. The signal amplitude refers to the current value or voltage value in the sample measurement loop composed of a sample signal generator, a sample capacitor under test, and a sample inductor; determining the nonlinear compensation coefficient of the circuit parameters corresponding to different signal ranges based on the sample signal amplitude dataset; determining the current signal amplitude of the measurement loop and determining the target signal range to which the current signal amplitude belongs, and compensating the initial circuit parameters using the nonlinear compensation coefficient of the circuit parameters corresponding to the target signal range, and using the compensated initial circuit parameters as the circuit parameters.

[0068] Specifically, taking the capacitance value as an example, the nonlinear compensation coefficients for different signal ranges are determined according to the following formula:

[0069] G(A) = G0 + G1A + G2A 2 +G3A 3

[0070] Specifically, by substituting different sample circuit parameters G(A) and their corresponding sample signal amplitudes A within the same signal range into the above formula, a system of equations is established to solve for the nonlinear coefficients of G0, G1, G2, and G3. Solving this system of equations yields the values ​​of G0, G1, G2, and G3 within the signal range. Thus, the values ​​of G0, G1, G2, and G3 within different signal ranges can be determined in the above manner. The current signal amplitude of the measurement loop is determined, and A in the above formula is replaced with the current signal amplitude. The signal range to which the current signal amplitude belongs is determined, and the current values ​​of G0, G1, G2, and G3 within that signal range are determined. These current values ​​of G0, G1, G2, and G3 are then substituted into the above formula, thereby calculating the nonlinearly compensated circuit parameters. This embodiment of the invention, by performing nonlinear compensation on the circuit parameters, avoids the influence of changes in the acquisition system signal during the acquisition process, thereby ensuring the accuracy of the circuit parameter determination and improving the accuracy of the capacitor loss angle determination.

[0071] Furthermore, electromagnetic interference is a significant factor affecting high-precision measurements during circuit parameter acquisition. This invention employs a multi-layered interference suppression strategy. At the hardware level, interference suppression utilizes a multi-layered shielding design to effectively suppress external electromagnetic interference; differential signal transmission reduces common-mode interference; and the selection of low-noise components improves the signal-to-noise ratio. At the software level, interference suppression includes adaptive digital filtering to adjust filter parameters in real time; correlation detection technology to extract useful signals; and outlier detection and removal to improve measurement reliability. Intelligent environmental assessment monitors the level of environmental electromagnetic interference in real time; automatically adjusts measurement parameters and integration time; and selects the optimal measurement strategy based on the interference situation.

[0072] 105. Based on circuit parameters and resonant frequency, determine the loss angle of the capacitor under test using the loss angle determination method.

[0073] In this embodiment of the invention, after determining the circuit parameters and the resonant frequency, it is necessary to determine the loss angle of the capacitor based on the above information. Therefore, step 105 specifically includes: if the resonance type is series resonance, then based on the resonant frequency f0, the resistance value R, and the capacitance value C, determine the quality factor Q of the measurement circuit, wherein... Based on the quality factor Q, the loss angle of the capacitor under test is determined.

[0074] Specifically, after determining the single-channel parameters R and C of the measurement circuit, as well as the resonant frequency of the measurement circuit, the above information is substituted into the formula for calculating the Q value to obtain the quality factor Q. Then, the tangent value tanα of the capacitor loss angle is determined according to the following formula, and finally, the capacitor loss angle α is determined based on tanα.

[0075]

[0076] If the resonance type is parallel resonance, the loss angle of the capacitor is determined using the loss angle determination method corresponding to parallel cointegration. If the resonance type is high-frequency resonance, the loss angle determination method corresponding to high-frequency resonance is used. In summary, this embodiment of the invention uses a three-level search strategy of adaptive frequency coarse scanning-fine scanning-precise positioning to determine the resonant frequency. This ensures accurate scanning of the resonant point while reducing scanning time, thereby improving the efficiency and accuracy of determining the capacitor loss angle. By compensating for the resonant frequency error, the influence of measurement errors on the resonant point can be avoided, thus improving the accuracy of the resonant frequency and consequently, the accuracy of determining the capacitor loss angle. By performing real-time error compensation on circuit parameters in various ways, the influence of external environment and acquisition device signals on circuit parameters can be avoided, thus ensuring the accuracy of circuit parameters and consequently improving the accuracy of determining the capacitor loss angle. By selecting the loss angle determination method based on the resonance type, personalized determination of the loss angle can be achieved, ensuring the accuracy of the capacitor loss angle determination.

[0077] According to the present invention, a method for determining the loss angle of a capacitor is provided. Compared with the current method of performing a uniform frequency scan of the circuit with a fixed step size and directly determining the loss angle of the capacitor based on the scan results, the present invention first performs a coarse frequency scan of the measurement circuit with a logarithmic frequency step size to determine the resonant region. Within the resonant region, a fine frequency scan of the measurement circuit with a linear frequency step size is performed to determine the resonant peak. Then, based on the impedance value of the reference frequency point around the resonant peak, the initial resonant frequency is determined and compensated to obtain the resonant frequency. After that, the resonance type is determined, and the circuit parameters and resonant frequency of the measurement circuit are analyzed using a loss angle determination method corresponding to the resonance type to obtain the loss angle of the capacitor under test. Therefore, by employing a three-level search strategy of adaptive frequency coarse scan, fine scan, and precise positioning to determine the resonant frequency, it is possible to ensure accurate scanning of the resonant point while reducing scanning time, thereby improving the efficiency and accuracy of determining the capacitor loss angle. Furthermore, by performing error compensation on the resonant frequency, the influence of measurement errors on the resonant point can be avoided, thus improving the accuracy of the resonant frequency and consequently, the accuracy of determining the capacitor loss angle. Finally, by performing real-time error compensation on the circuit parameters, the influence of the external environment on the circuit parameters can be avoided, thus ensuring the accuracy of the circuit parameters and further improving the accuracy of determining the capacitor loss angle.

[0078] Furthermore, to better illustrate the process of determining the capacitor loss angle described above, as a refinement and extension of the above embodiments, this invention provides another method for determining the capacitor loss angle, such as... Figure 12As shown, the method includes:

[0079] 201. Applied to a measurement circuit consisting of a signal generator, a capacitor under test, and an inductor, it responds to the loss angle of the capacitor under test to determine the signal, and performs a coarse frequency scan of the measurement circuit through the signal generator based on a logarithmic frequency step. During the coarse frequency scan, the resonant region of the capacitor under test is determined based on the rate of change of the impedance amplitude of the measurement circuit.

[0080] 202. Within the resonant region, a fine frequency scan is performed on the measurement circuit using a signal generator based on a linear frequency step size. During the fine frequency scan, the resonant peak is determined based on the impedance amplitude at each frequency point in the resonant region, and the resonant attribute information of the resonant peak is determined. The resonant attribute information includes the position and width of the resonant peak.

[0081] 203. Based on the resonance attribute information, select a reference frequency point in the preset area around the resonance peak, and determine the initial resonance frequency of the measurement circuit based on the impedance value corresponding to the reference frequency point.

[0082] Specifically, the gradient-guided intelligent resonance search algorithm uses a three-level search strategy of coarse scan, fine scan, and precise positioning to determine the initial resonant frequency of the measurement circuit.

[0083] 204. Based on the logarithmic equal interval method, select multiple calibration frequency points in the entire measurement frequency band of the measurement loop, determine the actual frequency and measurement frequency corresponding to the calibration frequency points, and construct a calibration factor determination function with frequency as independent variable and calibration factor as dependent variable based on the actual frequency and measurement frequency.

[0084] 205. Substitute the initial resonant frequency into the calibration factor determination function to calculate the calibration factor, obtain the calibration factor of the initial resonant frequency, and use the calibration factor to calibrate the initial resonant frequency to obtain the resonant frequency.

[0085] Specifically, the measurement circuit can be a sample measurement circuit composed of a sample signal generator, a sample capacitor, and a sample inductor. To address the frequency correlation error problem in broadband measurements, this embodiment of the invention establishes a frequency response compensation model based on multi-point calibration. Calibration frequency points are selected using a logarithmically evenly spaced method to ensure a reasonable distribution of calibration points throughout the entire measurement frequency band. The formula for determining the calibration frequency points is as follows:

[0086]

[0087] Where, N cal Where i is the number of calibration frequency points, i is the calibration frequency point identifier, and f is the number of calibration frequency points. max To measure the upper limit of the frequency band, f min To measure the lower limit of the frequency band, f cal(i)Let i be the i-th calibration frequency point. Then, determine the actual frequencies and the measured frequencies obtained by the measuring device for multiple frequency points in the measurement loop. Based on the actual and measured frequencies, a calibration factor determination function with frequency as the independent variable and calibration factor as the dependent variable is constructed using a piecewise cubic spline interpolation method, as shown below:

[0088]

[0089] Among them, C freq (f) is the calibration factor at frequency f, a i Here, n represents the polynomial difference coefficient, and i represents the polynomial order. The ratio of the actual frequency to the measured frequency at multiple calibration frequency points is determined as the calibration factor C. freq (f), based on the test frequency f and the corresponding C at multiple calibration frequency points. freq (f) and the above formula, construct the solution to a i The system of equations can be solved to obtain a. i The specific values. Then, the initial resonant frequency and a... i Substituting the specific values ​​into the above formula yields the calibration factor for the initial resonant frequency. The product of the calibration factor and the initial resonant frequency is then used as the calibrated resonant frequency. This embodiment of the invention improves the accuracy of resonant frequency determination by calibrating and compensating for the resonant frequency, thereby improving the accuracy of capacitor loss angle determination.

[0090] 206. Determine the resonance type of the measurement circuit, determine the loss angle determination method of the capacitor under test based on the resonance type, determine the initial circuit parameters of the measurement circuit, and perform error compensation on the initial circuit parameters in real time to obtain the circuit parameters.

[0091] In this embodiment of the invention, after determining the initial circuit parameters, the acquisition process of the initial circuit parameters is affected by the environment, signals from the acquisition device, etc. Therefore, in order to ensure the quality of the initial circuit parameters, it is necessary to correct and compensate the initial circuit parameters. The specific compensation method includes: obtaining the circuit parameter baseline value Baseline(t-1) at time t-1, and based on the circuit parameter baseline value Baseline(t-1) and the initial circuit parameter Measurement acquired at the current time t... ref (t), determine the baseline value of the circuit parameters at the current time t, Baseline(t), where Baseline(t) = α × Baseline(t-1) + (1-α) × Measurement ref (t), where α is the filter coefficient; the initial circuit parameters are measured based on the baseline value of the circuit parameters Baseline(t). ref(t) Perform baseline compensation and use the baseline-compensated initial circuit parameters as the circuit parameters.

[0092] Specifically, baseline drift of circuit parameters during measurement can affect measurement accuracy. Therefore, it is necessary to periodically measure open-circuit and short-circuit standards to monitor baseline changes; continuously monitor the DC bias of key nodes; and evaluate noise levels and stability in real time. Finally, circuit parameter compensation is performed based on noise levels and stability. The compensation process is as follows: First, determine the circuit parameter baseline (Baseline(t)) at the current time t (the time of initial circuit parameter acquisition). Then, use the circuit parameter baseline (Baseline(t)) to compensate for the initial circuit parameters. The compensation method is as follows: determine the difference between the circuit parameter baseline (Baseline(t)) at the current time t and the circuit parameter baseline (Baseline(t-1)) at the previous time t-1, compare the initial circuit parameters with this difference, and obtain the circuit parameters. This embodiment of the invention performs dynamic baseline determination and uses the dynamically determined baseline to calibrate and compensate for the circuit parameters. This avoids errors caused by baseline drift in the circuit parameters, ensures the accuracy of the circuit parameters, and thus improves the measurement accuracy of the capacitor loss angle.

[0093] In another embodiment of the present invention, in order to provide reliable circuit parameter measurement results, the method further includes: determining the temperature uncertainty U of the initial circuit parameters during the measurement process. A Signal uncertainty U B Baseline drift uncertainty U env Environmental electromagnetic interference uncertainty U cal Based on temperature uncertainty U A Signal uncertainty U B Baseline drift uncertainty U env Environmental electromagnetic interference uncertainty U cal Determine the total measurement uncertainty U of the circuit parameters. total ,in, Based on the total measurement uncertainty U total The initial circuit parameters are calibrated and compensated, and the compensated initial circuit parameters are used as the circuit parameters. Based on the total measurement uncertainty U... total One way to compensate for the initial circuit parameters is to reduce the total measurement uncertainty U. total The circuit parameters are obtained by multiplying them with the initial circuit parameters. The various uncertainties can be determined based on historical experimental data. For example, each uncertainty can be determined by analyzing the actual and measured circuit parameters over historical periods, considering both random errors from statistical analysis and systematic errors based on prior knowledge.

[0094] 207. Based on circuit parameters and resonant frequency, determine the loss angle of the capacitor under test using the loss angle determination method.

[0095] Specifically, based on circuit parameters and resonant frequency, the loss tangent of the capacitor under test is determined using a loss tangent determination method, and finally, the capacitor loss angle is determined based on the loss tangent. This embodiment of the invention's capacitor loss angle determination method can cover the measurement of capacitor loss angles across various frequency bands.

[0096] According to another method for determining the capacitor loss angle provided by the present invention, compared with the current method of performing a uniform frequency scan of the circuit with a fixed step size and directly determining the capacitor loss angle based on the scan results, the present invention first performs a coarse frequency scan of the measurement circuit with a logarithmic frequency step size to determine the resonance region. Within the resonance region, a fine frequency scan of the measurement circuit with a linear frequency step size is performed to determine the resonance peak. Then, based on the impedance value of the reference frequency point around the resonance peak, the initial resonance point frequency is determined and compensated to obtain the resonance point frequency. After that, the resonance type is determined, and the circuit parameters and resonance point frequency of the measurement circuit are analyzed using a loss angle determination method corresponding to the resonance type to obtain the loss angle of the capacitor under test. Therefore, by employing a three-level search strategy of adaptive frequency coarse scan, fine scan, and precise positioning to determine the resonant frequency, it is possible to ensure accurate scanning of the resonant point while reducing scanning time, thereby improving the efficiency and accuracy of determining the capacitor loss angle. Furthermore, by performing error compensation on the resonant frequency, the influence of measurement errors on the resonant point can be avoided, thus improving the accuracy of the resonant frequency and consequently, the accuracy of determining the capacitor loss angle. Finally, by performing real-time error compensation on the circuit parameters, the influence of the external environment on the circuit parameters can be avoided, thus ensuring the accuracy of the circuit parameters and further improving the accuracy of determining the capacitor loss angle.

[0097] Further, as Figure 1 In a specific implementation, this invention provides a device for determining the loss angle of a capacitor, applied to a measurement circuit consisting of a signal generator, a capacitor under test, and an inductor, such as... Figure 13 As shown, the device includes: a coarse frequency scanning unit 31, a fine frequency scanning unit 32, a frequency determination unit 33, a compensation unit 34, and a loss angle determination unit 35.

[0098] The coarse frequency scanning unit 31 can be used as a coarse frequency scanning unit to perform a coarse frequency scan on the measurement circuit based on the logarithmic frequency step size in response to the loss angle determination signal of the capacitor under test. During the coarse frequency scanning process, the resonant region of the capacitor under test is determined based on the rate of change of the impedance amplitude of the measurement circuit.

[0099] The fine-frequency scanning unit 32 can be used to perform fine-frequency scanning in the resonant region by means of the signal generator to the measurement circuit based on a linear frequency step. During the fine-frequency scanning process, the resonant peak is determined based on the impedance amplitude of each frequency point in the resonant region, and the resonant attribute information of the resonant peak is determined, wherein the resonant attribute information is the position and width of the resonant peak.

[0100] The frequency determination unit 33 can be used to select a reference frequency point in a preset area around the resonance peak based on the resonance attribute information, and determine the initial resonance point frequency of the measurement circuit based on the impedance value corresponding to the reference frequency point, and compensate the initial resonance point frequency to obtain the resonance point frequency.

[0101] The compensation unit 34 can be used to determine the resonance type of the measurement circuit, determine the loss angle determination method of the capacitor under test based on the resonance type, determine the initial circuit parameters of the measurement circuit, and perform error compensation on the initial circuit parameters in real time to obtain the circuit parameters.

[0102] The loss angle determination unit 35 can be used to determine the loss angle of the capacitor under test based on the circuit parameters and the resonant frequency using the loss angle determination method.

[0103] In specific application scenarios, in order to compensate for the initial resonant frequency, such as Figure 14 As shown, the frequency determination unit 33 includes a construction module 331 and a frequency calibration module 332.

[0104] The construction module 331 can be used to select multiple calibration frequency points in the entire measurement frequency band of the measurement loop based on logarithmic equal intervals, determine the actual frequency and measurement frequency corresponding to the calibration frequency points, and construct a calibration factor determination function with frequency as independent variable and calibration factor as dependent variable based on the actual frequency and measurement frequency.

[0105] The frequency calibration module 332 can be used to substitute the initial resonant frequency into the calibration factor determination function to calculate the calibration factor, obtain the calibration factor of the initial resonant frequency, and use the calibration factor to calibrate the initial resonant frequency to obtain the resonant frequency.

[0106] In specific application scenarios, in order to determine the resonance type of the measurement circuit, the compensation unit 34 can be used to determine the impedance frequency characteristic curve and impedance phase of the measurement circuit during the frequency scanning process of the signal generator to the measurement circuit; extract the peak value, valley value and rate of change of the impedance frequency characteristic curve using frequency domain features, and determine the frequency domain resonance type of the measurement circuit based on the peak value, valley value and rate of change; analyze the change characteristics of the impedance phase using phase domain features, and determine the phase domain resonance type of the measurement circuit based on the change characteristics; and determine the resonance type of the measurement circuit based on the frequency domain resonance type and the phase domain resonance type.

[0107] In specific application scenarios, in order to perform error compensation on the initial circuit parameters in real time, the compensation unit 34 includes an acquisition module 341, a determination module 342, and a compensation module 343.

[0108] The acquisition module 341 can be used to acquire a sample circuit parameter dataset, wherein the sample circuit parameter dataset includes sample circuit parameters P under different sample temperature values ​​T. T And the reference circuit parameters P0 at the reference temperature T0.

[0109] The determining module 342 can be used to determine the temperature compensation coefficients α1 and α2 of the initial circuit parameters based on the sample circuit parameter dataset, wherein...

[0110] The compensation module 343 can be used to determine the acquisition temperature value at the time of acquisition of the initial circuit parameters, and to compensate the initial circuit parameters based on the temperature compensation coefficients α1 and α2, the acquisition temperature value, and the reference temperature value T0, and to use the compensated initial circuit parameters as the circuit parameters.

[0111] In specific application scenarios, in order to perform error compensation on the initial circuit parameters in real time, the acquisition module 341 can also be used to acquire a sample signal amplitude dataset, wherein the sample signal amplitude dataset includes sample signal amplitudes in different signal ranges and sample circuit parameters under the sample signal amplitudes. The signal amplitude refers to the current value or voltage value in the sample measurement loop composed of the sample signal generator, the sample capacitor under test, and the sample inductor.

[0112] The determining module 342 can also be used to determine the nonlinear compensation coefficients of circuit parameters corresponding to different signal ranges based on the sample signal amplitude dataset.

[0113] The compensation module 343 can also be used to determine the current signal amplitude of the measurement loop, determine the target signal range to which the current signal amplitude belongs, and use the nonlinear compensation coefficient of the circuit parameters corresponding to the target signal range to compensate the initial circuit parameters, and use the compensated initial circuit parameters as the circuit parameters.

[0114] In specific application scenarios, in order to perform error compensation on the initial circuit parameters in real time, the acquisition module 341 can also be used to acquire the circuit parameter baseline value Baseline(t-1) at time t-1, and based on the circuit parameter baseline value Baseline(t-1) and the initial circuit parameter Measurement collected at the current time t, ref (t), determine the baseline value of the circuit parameters at the current time t, Baseline(t), where Baseline(t) = α × Baseline(t-1) + (1-α) × Measurement ref (t), where α is the filter coefficient.

[0115] The compensation module 343 can also be used to adjust the initial circuit parameters based on the circuit parameter baseline value Baseline(t). ref (t) Perform baseline compensation and use the baseline-compensated initial circuit parameters as the circuit parameters.

[0116] In specific application scenarios, circuit parameters include resistance value R and capacitance value C. To determine the loss angle of the capacitor under test, the loss angle determination unit 35 can specifically be used to determine the quality factor Q of the measurement circuit based on the resonant frequency f0, the resistance value R, and the capacitance value C, if the resonance type is series resonance. Based on the quality factor Q, the loss angle of the capacitor under test is determined.

[0117] It should be noted that other corresponding descriptions of the functional modules involved in the capacitor loss angle determination device provided in this embodiment of the invention can be found in the following references. Figure 1 The corresponding description of the method shown will not be repeated here.

[0118] Based on the above Figure 1The method shown, correspondingly, also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the following steps: applied to a measurement circuit consisting of a signal generator, a capacitor under test, and an inductor; responding to a loss angle determination signal of the capacitor under test; performing a coarse frequency scan of the measurement circuit through the signal generator based on a logarithmic frequency step size; during the coarse frequency scan, determining the resonant region of the capacitor under test based on the rate of change of the impedance amplitude of the measurement circuit; and within the resonant region, performing a fine frequency scan of the measurement circuit through the signal generator based on a linear frequency step size; during the fine frequency scan, determining the resonant peak based on the impedance amplitude at each frequency point in the resonant region. The process involves determining the resonance attribute information of the resonance peak, where the resonance attribute information includes the position and width of the resonance peak; selecting a reference frequency point within a preset region around the resonance peak based on the resonance attribute information; determining the initial resonance frequency of the measurement circuit based on the impedance value corresponding to the reference frequency point; compensating for the initial resonance frequency to obtain the resonance frequency; determining the resonance type of the measurement circuit; determining the loss angle determination method for the capacitor under test based on the resonance type; determining the initial circuit parameters of the measurement circuit; and performing error compensation on the initial circuit parameters in real time to obtain the circuit parameters; and determining the loss angle of the capacitor under test based on the circuit parameters and the resonance frequency using the loss angle determination method.

[0119] Based on the above Figure 1 The method shown and Figure 13 The embodiment of the device shown in the figure, the embodiment of the present invention also provides a physical structure diagram of a computer device, such as Figure 15As shown, the computer device includes: a processor 41, a memory 42, and a computer program stored in the memory 42 and executable on the processor. Both the memory 42 and the processor 41 are mounted on a bus 43. When the processor 41 executes the program, it performs the following steps: applied to a measurement circuit consisting of a signal generator, a capacitor under test, and an inductor; responding to a loss angle determination signal of the capacitor under test; performing a coarse frequency scan of the measurement circuit through the signal generator based on a logarithmic frequency step; during the coarse frequency scan, determining the resonant region of the capacitor under test based on the rate of change of the impedance amplitude of the measurement circuit; within the resonant region, performing a fine frequency scan of the measurement circuit through the signal generator based on a linear frequency step; during the fine frequency scan, determining the resonant region based on the resonant region... The impedance amplitude at each frequency point determines the resonant peak, and the resonant attribute information of the resonant peak is determined, wherein the resonant attribute information is the position and width of the resonant peak; based on the resonant attribute information, a reference frequency point is selected in a preset area around the resonant peak, and based on the impedance value corresponding to the reference frequency point, the initial resonant frequency of the measurement circuit is determined, and the initial resonant frequency is compensated to obtain the resonant frequency; the resonance type of the measurement circuit is determined, and based on the resonance type, the loss angle determination method of the capacitor under test is determined, the initial circuit parameters of the measurement circuit are determined, and the initial circuit parameters are error compensated in real time to obtain the circuit parameters; based on the circuit parameters and the resonant frequency, the loss angle of the capacitor under test is determined using the loss angle determination method.

[0120] The present invention employs a coarse frequency scan of the measurement circuit using a logarithmic frequency step size to determine the resonant region. Within this region, a fine frequency scan is performed using a linear frequency step size to determine the resonant peak. Then, based on the impedance values ​​of reference frequency points around the resonant peak, the initial resonant frequency is determined and compensated to obtain the resonant frequency. The resonance type is then identified, and a loss angle determination method corresponding to the resonance type is used to analyze the circuit parameters and resonant frequency of the measurement circuit, yielding the loss angle of the capacitor under test. This three-level search strategy of adaptive frequency coarse scan, fine scan, and precise positioning determines the resonant frequency, ensuring accurate scanning of the resonant point while reducing scan time, thus improving the efficiency and accuracy of determining the capacitor's loss angle. Error compensation for the resonant frequency avoids the influence of measurement errors, improving the accuracy of the resonant frequency and consequently the accuracy of determining the capacitor's loss angle. Real-time error compensation for circuit parameters avoids the influence of external environmental factors, ensuring the accuracy of the circuit parameters and further improving the accuracy of determining the capacitor's loss angle.

[0121] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0122] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the loss angle of a capacitor, characterized in that, Applied to measurement circuits consisting of a signal generator, a capacitor under test, and an inductor, including: In response to the loss angle determination signal of the capacitor under test, a coarse frequency scan is performed on the measurement circuit through the signal generator based on a logarithmic frequency step. During the coarse frequency scan, the resonant region of the capacitor under test is determined based on the rate of change of the impedance amplitude of the measurement circuit. Within the resonant region, a fine frequency scan is performed on the measurement circuit via the signal generator based on a linear frequency step. During the fine frequency scan, the resonant peak is determined based on the impedance amplitude at each frequency point in the resonant region, and the resonant attribute information of the resonant peak is determined, wherein the resonant attribute information is the position and width of the resonant peak. Based on the resonance attribute information, a reference frequency point is selected in a preset area around the resonance peak, and the initial resonance point frequency of the measurement circuit is determined based on the impedance value corresponding to the reference frequency point. The initial resonance point frequency is then compensated to obtain the resonance point frequency. The resonance type of the measurement circuit is determined, the loss angle determination method of the capacitor under test is determined based on the resonance type, the initial circuit parameters of the measurement circuit are determined, and the initial circuit parameters are compensated for errors in real time to obtain the circuit parameters. Based on the circuit parameters and the resonant frequency, the loss angle of the capacitor under test is determined using the loss angle determination method.

2. The method according to claim 1, characterized in that, Compensating for the initial resonant frequency to obtain the resonant frequency includes: Multiple calibration frequency points are selected within the entire measurement frequency band of the measurement loop using a logarithmic equidistant method. The actual frequency and measurement frequency corresponding to the calibration frequency points are determined. Based on the actual frequency and measurement frequency, a calibration factor determination function is constructed with frequency as the independent variable and calibration factor as the dependent variable. The initial resonant frequency is substituted into the calibration factor determination function to calculate the calibration factor, thereby obtaining the calibration factor of the initial resonant frequency. The initial resonant frequency is then calibrated using the calibration factor to obtain the resonant frequency.

3. The method according to claim 1, characterized in that, Determining the resonance type of the measurement circuit includes: During the frequency scanning process of the signal generator towards the measurement circuit, the impedance frequency characteristic curve and impedance phase of the measurement circuit are determined. The peak value, valley value, and rate of change of the impedance frequency characteristic curve are extracted using frequency domain features. Based on the peak value, valley value, and rate of change, the frequency domain resonance type of the measurement circuit is determined. The phase domain features are analyzed to determine the phase domain resonance type of the impedance. Based on the frequency domain resonance type and the phase domain resonance type, the resonance type of the measurement circuit is determined.

4. The method according to claim 1, characterized in that, Real-time error compensation is performed on the initial circuit parameters to obtain the circuit parameters, including: Obtain a sample circuit parameter dataset, wherein the sample circuit parameter dataset includes sample circuit parameters P at different sample temperature values ​​T. T And the reference circuit parameter P0 at the reference temperature value T0; Based on the sample circuit parameter dataset, the temperature compensation coefficients α1 and α2 of the initial circuit parameters are determined, wherein, Determine the acquisition temperature value at the time of initial circuit parameter acquisition, and compensate the initial circuit parameters based on the temperature compensation coefficients α1 and α2, the acquisition temperature value, and the reference temperature value T0, and use the compensated initial circuit parameters as the circuit parameters.

5. The method according to claim 1, characterized in that, Real-time error compensation is performed on the initial circuit parameters to obtain the circuit parameters, including: Obtain a sample signal amplitude dataset, wherein the sample signal amplitude dataset includes sample signal amplitude A in different signal ranges and sample circuit parameters G(A) under the sample signal amplitude A. The signal amplitude refers to the current value or voltage value in the sample measurement circuit composed of the sample signal generator, the sample capacitor under test, and the sample inductor. Based on the sample signal amplitude dataset, determine the nonlinear compensation coefficients of the circuit parameters corresponding to different signal ranges; The current signal amplitude of the measurement loop is determined, and the target signal range to which the current signal amplitude belongs is determined. The initial circuit parameters are compensated using the nonlinear compensation coefficient of the circuit parameters corresponding to the target signal range, and the compensated initial circuit parameters are used as the circuit parameters.

6. The method according to claim 1, characterized in that, Real-time error compensation is performed on the initial circuit parameters to obtain the circuit parameters, including: Obtain the circuit parameter baseline value Baseline(t-1) at time t-1, and based on the circuit parameter baseline value Baseline(t-1) and the initial circuit parameter Measurement collected at the current time t... ref (t), determine the baseline value of the circuit parameters at the current time t, Baseline(t), where Baseline(t) = α × Baseline(t-1) + (1-α) × Measurement ref (t), where α is the filter coefficient; Based on the circuit parameter baseline value Baseline(t), the initial circuit parameter Measurement is... ref (t) Perform baseline compensation and use the baseline-compensated initial circuit parameters as the circuit parameters.

7. The method according to claim 1, characterized in that, The circuit parameters include resistance value R and capacitance value C; Based on the circuit parameters and the resonant frequency, the loss angle of the capacitor under test is determined using the loss angle determination method, including: If the resonance type is series resonance, then the quality factor Q of the measurement circuit is determined based on the resonant frequency f0, the resistance value R, and the capacitance value C, wherein... Based on the quality factor Q, the loss angle of the capacitor under test is determined.

8. A device for determining the loss angle of a capacitor, characterized in that, Applied to measurement circuits consisting of a signal generator, a capacitor under test, and an inductor, including: A coarse frequency scanning unit is used to respond to the loss angle determination signal of the capacitor under test, and to perform a coarse frequency scan on the measurement circuit through the signal generator based on a logarithmic frequency step. During the coarse frequency scan, the resonant region of the capacitor under test is determined based on the rate of change of the impedance amplitude of the measurement circuit. A fine-frequency scanning unit is used to perform fine-frequency scanning in the resonant region by means of the signal generator to the measurement circuit based on a linear frequency step. During the fine-frequency scanning process, the resonant peak is determined based on the impedance amplitude of each frequency point in the resonant region, and the resonant attribute information of the resonant peak is determined, wherein the resonant attribute information is the position and width of the resonant peak. The frequency determination unit is used to select a reference frequency point in a preset area around the resonance peak based on the resonance attribute information, and determine the initial resonance point frequency of the measurement circuit based on the impedance value corresponding to the reference frequency point, and compensate the initial resonance point frequency to obtain the resonance point frequency. The compensation unit is used to determine the resonance type of the measurement circuit, determine the loss angle determination method of the capacitor under test based on the resonance type, determine the initial circuit parameters of the measurement circuit, and perform error compensation on the initial circuit parameters in real time to obtain the circuit parameters. The loss angle determination unit is used to determine the loss angle of the capacitor under test based on the circuit parameters and the resonant frequency using the loss angle determination method.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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