A method for determining energy storage capacitor in electronic detonator

Abstract

The present application discloses a method for determining an energy storage capacitor in an electronic detonator, which relates to the technical field of electronic detonators, and comprises: charging the energy storage capacitor to a preset voltage V1 through a constant current source; measuring the leakage current of the energy storage capacitor; discharging the energy storage capacitor in segments; adjusting the sampling frequency and the AD conversion rate according to the instantaneous voltage of the energy storage capacitor in each discharge time period; performing curve fitting on the voltage-time data pairs collected in multiple discharge time periods; calculating the voltage value V2 at the discharge termination moment; and calculating the leakage charge Q according to the leakage current and the discharge duration t. leak ; Distribute the leakage charge evenly throughout the discharge process, which is equivalent to a correction voltage ΔV leak ; Using the correction voltage ΔV leak The voltage value V2 is corrected to obtain a corrected voltage value V2'; according to V1, V2', t, the energy storage capacitor C is calculated. In view of the low measurement accuracy of the energy storage capacitor in the electronic detonator in the prior art, the present application improves the measurement accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of electronic detonators, and in particular to a method for determining an energy storage capacitor in an electronic detonator. Background Art

[0002] Electronic detonators are electronic ignition devices used to detonate explosives. They are widely used in mining, blasting, aerospace and other fields. Electronic detonators store electrical energy through energy storage capacitors. After receiving the detonation signal, they release the electrical energy in the energy storage capacitors to the electric heating elements, causing the electric heating elements to heat up rapidly and ignite the explosives, thereby achieving the detonation of the detonator. The energy storage capacitor is a key component of the electronic detonator. Its capacity and performance stability directly affect the detonation energy and reliability of the detonator.

[0003] With the continuous development of electronic detonator technology, higher and higher requirements are placed on the safety, reliability and consistency of detonators. In order to ensure the reliable initiation of electronic detonators, it is necessary to accurately measure and screen the energy storage capacitors and eliminate products with large capacity deviations or unstable performance. At present, the measurement of energy storage capacitors mainly adopts the discharge method, that is, charging the capacitor to a preset voltage, then releasing the electricity through the discharge circuit, and calculating the capacitor capacity based on the discharge duration and voltage change.

[0004] However, existing energy storage capacitor measurement methods generally have problems such as low accuracy and susceptibility to environmental interference. Specifically, in the actual discharge process, due to the influence of the equivalent series resistance and insulation leakage current of the energy storage capacitor itself, the discharge is not a complete exponential decay process, and the error is large when the capacitance is calculated using a simplified discharge model; for energy storage capacitors with smaller capacity, the discharge time is extremely short and the voltage drops sharply, and conventional discharge measurement circuits are difficult to take into account both measurement sensitivity and dynamic range. Summary of the invention

[0005] In view of the problem of low measurement accuracy of energy storage capacitors in electronic detonators in the prior art, the present application provides a method for determining the energy storage capacitors in electronic detonators, which fully considers the leakage current, equivalent series resistance, dielectric absorption effect and temperature characteristics of the energy storage capacitor, adopts segmented constant current discharge and dynamic sampling, etc., to analyze the measurement errors of key parameters, and improves the measurement accuracy.

[0006] The purpose of this application is achieved through the following technical solutions.

[0007] The present application provides a method for determining an energy storage capacitor in an electronic detonator, comprising: S1, charging the energy storage capacitor to a preset voltage V through a constant current source 1, monitor the charging current and voltage at the same time, and judge that the charging is completed when the charging current drops below the preset threshold; specifically, select a suitable constant current source as the charging power supply for the energy storage capacitor. Commonly used constant current sources can be dedicated integrated circuit chips (such as LM334, REF200, etc.), or constant current source circuits based on operational amplifiers. According to the capacity and rated charging voltage of the energy storage capacitor, calculate the appropriate charging current value. The charging current should not be too large to avoid damage to the capacitor; nor should it be too small to avoid too long charging time. Generally, the charging current can be set between 0.1C and 1C of the capacitor capacity, where C represents the capacitance value of the capacitor in farads (F). According to the rated working voltage of the energy storage capacitor, preset the charging target voltage value. In order to leave a certain margin, the preset voltage value can be slightly lower than the rated working voltage, generally between 80% and 90%. During the charging process, monitor the changes in the charging current and the voltage across the capacitor in real time. A high-precision current sensor (such as a sampling resistor + op amp circuit, Hall current sensor, etc.) can be used to measure the charging current, and a high-impedance voltage sampling circuit can be used to measure the voltage across the capacitor, and the measured value can be transmitted to the main control unit for recording and judgment. As charging progresses, the voltage across the capacitor continues to rise and the charging current gradually decreases. When the capacitor voltage approaches the preset value, the charging current will drop rapidly. By setting a current threshold (such as 1% or 5% of the preset charging current), when the measured current drops below the threshold, it can be judged that the charging is basically completed, and charging can be stopped at this time.

[0008] S2, after charging is completed, the charging circuit is cut off and the leakage current of the energy storage capacitor is measured; S3, by controlling the discharge switch, the energy storage capacitor is discharged in segments, and the discharge process is divided into multiple time periods, each of which is equal; the segmented discharge includes: by controlling the on and off of the semiconductor switch, intermittent discharge is performed, and the discharge pulse width is controllable;

[0009] S4, in each discharge time period, according to the instantaneous voltage of the energy storage capacitor, the sampling frequency and the AD conversion rate are adjusted; specifically, in the early stage of discharge, the capacitor voltage changes rapidly, and the sampling frequency should be set to a higher value to obtain more voltage sample points and accurately capture the rapid change process of the voltage; as the discharge progresses, the capacitor voltage changes gradually slows down, and the sampling frequency can be reduced accordingly to reduce the amount of data and the processing burden; several voltage thresholds can be pre-set, and when the capacitor voltage drops below a certain threshold, the adjustment of the sampling frequency is triggered. The selection of the threshold can be determined according to the discharge characteristic curve of the capacitor. The adjustment of the AD conversion rate is carried out simultaneously with the adjustment of the sampling frequency. In the early stage of discharge, the sampling frequency is high, and accordingly, the AD conversion rate should also be set to a higher value to ensure that the sampled voltage value can be converted into a digital value in time to keep up with the pace of the sampling frequency; as the sampling frequency decreases, the AD conversion rate can also be reduced accordingly to match the sampling frequency, reduce conversion time and power consumption; the adjustment of the AD conversion rate needs to consider the performance limitations of the ADC, such as the maximum conversion rate, conversion accuracy, etc., and cannot exceed the working range of the ADC. Preferably, in order to achieve dynamic adjustment of the sampling frequency and the AD conversion rate, a special clock and control circuit needs to be designed. The clock circuit is responsible for generating sampling clocks and conversion clocks of different frequencies, and the control circuit is responsible for selecting the appropriate clock frequency and controlling the operation of the ADC according to the instantaneous value of the capacitor voltage. Due to the dynamic adjustment of the sampling frequency and the AD conversion rate, the intervals of the collected voltage sample points on the time axis are no longer uniform. In order to facilitate subsequent data processing and analysis, the collected data needs to be cached and transmitted. A FIFO (first in, first out) buffer can be used to temporarily store data, record the timestamp corresponding to each data point, and then send the data packet to the main control unit for processing.

[0010] S5, curve fitting is performed on the voltage-time data pairs collected in multiple discharge time periods to obtain a discharge curve equation; based on the discharge curve equation, the voltage value V at the discharge termination time is calculated. 2 ; S6, calculate the leakage charge Q according to the leakage current and discharge duration t leak ; Distribute the leakage charge evenly throughout the discharge process, which is equivalent to a correction voltage ΔV leak ; Using the correction voltage ΔV leak For voltage value V 2 Correction is performed to obtain the corrected voltage value V 2 '; S7, according to the preset voltage V 1 , the corrected voltage value V 2 ', discharge duration t, calculate the energy storage capacitance C.

[0011] Among them, S2, after charging is completed, cuts off the charging circuit and measures the leakage current of the energy storage capacitor, including: S21, selects a suitable operational amplifier (op amp) as the core device of the current-voltage conversion circuit. Commonly used op amp models include CA3140, LMP7721, ADA4530, etc. Feedback resistor R f The resistance value of R determines the conversion sensitivity of the current-to-voltage conversion circuit, that is, the output voltage amplitude generated by the unit leakage current. f The resistance value can be selected between 10kΩ and 10GΩ. To reduce leakage current and noise, R f A high insulation resistor should be selected, such as a metal film resistor with glass glaze package. Connect the positive electrode of the energy storage capacitor to the inverting input terminal of the op amp, and the negative electrode to ground; the non-inverting input terminal of the op amp is directly grounded, and the output terminal is connected to the feedback resistor R f One end, R f The other end is connected to the inverting input of the operational amplifier to form a feedback current path.

[0012] S22, the adjustable gain amplifier adopts a circuit topology composed of a digital potentiometer and an operational amplifier. The resistance of the digital potentiometer determines the feedback resistance of the operational amplifier, and then determines the gain of the amplifier. By changing the resistance of the digital potentiometer, the amplifier gain can be continuously adjusted. Common adjustable gain amplifier circuits include the following: inverting proportional operational amplifier, non-inverting proportional operational amplifier, and differential proportional operational amplifier. A digital potentiometer is a potentiometer that changes its resistance through a digital control interface. Common digital potentiometer models include AD5241, MCP4151, X9C102, etc. The digital potentiometer is connected to the controller through the SPI interface. The controller writes the resistance control value to the digital potentiometer through the SPI interface to change its resistance. According to the expected range of the leakage current and the range of the ADC, the controller dynamically adjusts the resistance of the digital potentiometer according to the preset control strategy to achieve adaptive adjustment of the amplifier gain.

[0013] S23, input the voltage signal output by the adjustable gain amplifier to the ADC for sampling, and convert the analog voltage into a digital quantity. Commonly used high-resolution ADC models include AD7190, ADS1262, LTC2400, etc. The controller monitors the output digital quantity of the ADC in real time, calculates the current change ΔI and the time interval Δt between two adjacent sampling points, and obtains the instantaneous change rate v = ΔI / Δt. The change rate v is compared with the preset threshold v 1 and v 2 For comparison, when v>v 1 When the sampling frequency is increased to f 1 ; When v<v 2 When v 2 ≤v≤v 1When , the current sampling frequency is maintained. 1 and f 2 It can be set according to the maximum sampling rate of the ADC and the expected change characteristics of the leakage current. At each sampling frequency, the number of sampling points n in each measurement cycle is dynamically adjusted according to the change rate v. When v is large, n is increased to obtain more data points; when v is small, n is reduced to reduce the amount of data. The value range of n can be set according to the measurement time and data processing capability. Through the adaptive sampling strategy, the sampling frequency and the number of sampling points can be automatically adjusted when the leakage current change rate changes, while ensuring the measurement accuracy, while optimizing the data volume and processing burden.

[0014] S24, multiple sampling and arithmetic averaging. In each sampling period, the ADC continuously samples multiple digital quantities, and the controller performs arithmetic averaging on these digital quantities to obtain the average sampling value of the sampling period. Suppose the digital quantity collected in the i-th sampling period is x(i,j), j=1,2,.....,n, where n is the number of sampling points, then the average sampling value of the sampling period is: Through multiple sampling and arithmetic averaging, the impact of random errors on the sampling values ​​can be effectively reduced.

[0015] Standard deviation calculation and threshold judgment, in order to determine whether the sampled value is stable, it is necessary to calculate the standard deviation of the sampled value in multiple consecutive sampling periods and compare it with the preset threshold. The standard deviation reflects the degree to which the sampled value deviates from the average value and is an important indicator for measuring the stability of the sampling. Suppose the average sampled value of m consecutive sampling periods is: avg (i), i = 1, 2, ..., m, then the standard deviation of these m sampling values ​​is:

[0016] Among them, x mean is the arithmetic mean of m average sample values: The controller calculates the standard deviation std of m consecutive sampling cycles in real time dev , and compare it with the preset threshold ε. When k consecutive standard deviations are all smaller than the threshold, that is, std dev <ε for k consecutive std dev If both are true, the sampled value is considered stable and the next measurement can be performed. Suppose the average leakage current in the i-th sampling period is I leak (i), the average sampling value is x_avg(i), and the voltage error introduced by the leakage current is ΔV leak (i), then the corrected sampling value is: x avg_corr (i) = x avg (i) -ΔV leak (i), where the voltage error ΔV introduced by the leakage current leak (i) and leakage current Ileak (i) Proportional to the equivalent impedance Z of the sampling circuit: ΔV leak (i)=I leak (i) × Z.

[0017] S25, converting the average sampling value into a measurement value linearly related to the leakage current according to the feedback resistance of the operational amplifier, the resistance value of the digital potentiometer, the fixed gain of the amplifier and the range of the AD converter; S26, repeating steps S23 to S25, measuring the leakage current multiple times, and performing consistency check, when the maximum deviation of the continuous multiple measurement results is less than the threshold, taking the arithmetic mean as the final leakage current measurement value I leak .

[0018] Furthermore, the correction voltage ΔV leak , calculated by the following formula:

[0019]

[0020] Where, ΔV leak is the correction voltage; C 0 is the initial estimated value of the energy storage capacitor; T(i×Δt) and V(i×Δt) represent the average temperature and average voltage in the i-th time interval, respectively, in degrees Celsius (℃) and volts (V); N represents the division of the continuous time t into N small areas, and the duration of each area is Δt = t / N; T 0 and V 0 are the reference temperature and reference voltage, usually 25°C and rated working voltage; α and β are the temperature correction coefficient and voltage correction coefficient of leakage current, in units of 1 / °C and 1 / V, respectively, which need to be obtained through experimental testing; [1+α×(T(i×Δt)-T 0 )] and [1+β×(V(i×Δt)-V 0 )] are the temperature correction factor and voltage correction factor, respectively, which are used to compensate for the measurement error caused by the leakage current changing with temperature and voltage.

[0021] Specifically, the correction voltage ΔV leak The calculation formula introduces multiple correction factors, comprehensively considering the changing characteristics of leakage current with time, temperature and voltage, which can effectively compensate for the measurement errors caused by various factors, thereby improving the accuracy of energy storage capacitor capacity measurement. The formula divides the continuous discharge time t into segments and divides it into N small intervals, each with a duration of Δt. By accumulating the leakage current in each time interval, the change process of leakage current with time can be more finely characterized, improving the accuracy of integral calculation. The temperature correction factor [1+α×(T(i×Δt)-T 0)], where α is the temperature correction coefficient of the leakage current, T(i×Δt) is the average temperature in the i-th time interval, and T0 is the reference temperature. This correction factor can compensate for the measurement error caused by the change of leakage current with temperature. When the temperature rises, the conductivity of the capacitor medium increases and the leakage current increases; when the temperature decreases, the leakage current decreases. The introduction of the temperature correction factor can obtain consistent leakage current measurement results under different temperature conditions. The voltage correction factor [1+β×(V(i×Δt)-V 0 )], where β is the voltage correction coefficient of the leakage current, V(i×Δt) is the average voltage in the i-th time interval, V 0 is the reference voltage. This correction factor can compensate for the measurement error caused by the change of leakage current with voltage. The leakage current has a nonlinear relationship with the voltage across the capacitor. The higher the voltage, the greater the leakage current. By introducing the voltage correction factor, normalized leakage current measurement results can be obtained at different voltage levels. The initial estimated value C of the energy storage capacitor is used in the formula 0 , as a reference value for converting leakage charge to voltage. In practical applications, the nominal capacity or empirical value can be used as an initial estimate to calculate a corrected voltage value. Then, the energy storage capacitor capacity is recalculated using the corrected voltage to obtain an estimate closer to the true value. Through iterative calculations, C is continuously updated. 0 and ΔV leak , until it converges to a stable measurement result. Taking into account the two influencing factors of temperature and voltage, the corresponding correction coefficients α and β are introduced to quantify the sensitivity of the leakage current to temperature and voltage. By correcting the leakage current through the correction factor, the measurement error caused by changes in environmental conditions and device parameter drift can be effectively compensated, and the consistency and repeatability of the measurement results can be improved. The calculation formula of the correction voltage is universal and applicable to various types of capacitor devices. Only by reasonably setting the reference temperature T0, reference voltage V0 and correction coefficients α and β according to the characteristics of the specific device can an optimized correction effect be obtained.

[0022] Furthermore, S25, considering the influence of the input offset voltage, input offset current, input bias current of the operational amplifier on the measurement accuracy, as well as the temperature drift characteristics of the digital potentiometer, the original linear relationship is improved, and multiple correction factors are introduced to obtain the improved leakage current calculation formula:

[0023] Among them, I leak Indicates the leakage current measurement value in ampere (A); V out Indicates the average sampling value of the AD converter, that is, the digital output value; D Nis the nominal resistance of the digital potentiometer at a reference temperature (such as 25°C), in ohms (Ω); ξ is the temperature drift coefficient of the digital potentiometer, which indicates the relative rate of change of the digital potentiometer resistance with temperature, in 1 / °C; ΔT is the difference between the actual operating temperature of the digital potentiometer and the reference temperature, in °C; R f Represents the operational amplifier feedback resistor value; G ain is the fixed gain of the amplifier, which is a dimensionless constant; n is the number of conversion bits of the AD converter; I os I is the input offset current of the operational amplifier, in amperes (A), which indicates the leakage current at the input of the operational amplifier, which will cause measurement deviation; b V is the input bias current of the operational amplifier, in amperes (A), which indicates the DC current that the input stage of the operational amplifier needs to obtain from the signal source, and will also cause measurement deviation; os I is the input offset voltage of the operational amplifier, in volts (V), which indicates the DC voltage difference at the input of the operational amplifier. After being converted into current by the feedback resistor, it will also cause measurement deviation. os ,I b and V os These are intrinsic parameters of the operational amplifier and can be obtained by referring to the device manual. When calculating the leakage current, the deviation component caused by them needs to be deducted from the measured value.

[0024] Specifically, the temperature drift coefficient ξ of the digital potentiometer and the difference ΔT between the actual operating temperature and the reference temperature are introduced into the formula. The multiplicative correction term (1+ξ×ΔT) can be used to compensate for the measurement error caused by the change in the digital potentiometer resistance with temperature. The temperature coefficient of the digital potentiometer resistance is usually at the ppm level. If it is not compensated, the measurement result will drift with the ambient temperature. By introducing the temperature compensation term, consistent leakage current measurements can be obtained under different temperature conditions. The formula takes into account the input offset current I of the operational amplifier. os , Input bias current I b and input offset voltage V os The impact on the measurement results. os and I b It will introduce additional current components and affect the leakage current measurement; V os The feedback resistor R f An additional voltage drop is generated on the MOSFET, which introduces measurement errors. By introducing I os ,I b and These three corrections can eliminate the impact of the non-ideal characteristics of the operational amplifier on the measurement results and improve the measurement accuracy. The formula includes the fixed gain G of the amplifier. ainThe gain of the amplifier amplifies the tiny leakage current signal to a voltage range that the ADC can effectively resolve, thereby improving the measurement sensitivity. The number of conversion bits n of the AD converter determines the resolution of the digital output. The higher the number of conversion bits, the higher the resolution and the smaller the quantization error. In the formula, the ADC output value V out Divide by 2 n , the digital quantity can be restored to the actual voltage value, and the leakage current value can be restored in combination with the amplifier gain. This formula comprehensively considers and corrects various factors that affect the leakage current measurement, such as digital potentiometer temperature drift, operational amplifier parameters, amplifier gain, and AD conversion accuracy. By introducing multiple corrections into the measured value, the influence of various error sources can be weakened, and a more accurate and stable leakage current measurement result can be obtained. The parameters involved in this formula, such as the digital potentiometer resistance, operational amplifier feedback resistor, amplifier gain, AD conversion bit number, etc., can be determined by hardware circuit design and device selection. The temperature drift coefficient can be obtained through experimental testing or by referring to the device manual. The offset voltage and current of the operational amplifier can be compensated by zero calibration or automatic zeroing circuit. Therefore, this formula has strong engineering applicability and is easy to implement in hardware circuits.

[0025] Further, S3, by controlling the on and off of the semiconductor switch, intermittent discharge is performed, including: S31, in the discharge test of the energy storage capacitor, it is necessary to control the discharge process by controlling the on and off of the discharge circuit. This can be achieved by connecting a controllable switch device (such as MOSFET, IGBT, etc.) in series in the discharge circuit. When the switch is turned on, the energy storage capacitor is discharged through the discharge circuit; when the switch is turned off, the discharge circuit is disconnected and the energy storage capacitor stops discharging. By periodically switching and controlling the switch device, a series of discharge control pulses can be generated to control the discharge process of the energy storage capacitor. The discharge control pulse can be generated by a programmable controller (such as FPGA, MCU, etc.). The controller outputs a digital control signal through its I / O interface to drive the switch device in the discharge circuit. The digital control signal is a periodic rectangular wave pulse, and its high level corresponds to the switch on state, and the low level corresponds to the switch off state. Taking a commonly used MCU as an example, its built-in general timer (such as TIM) can realize the generation of discharge control pulses. TIM can work in output comparison mode, and generate a PWM waveform with adjustable duty cycle and frequency by setting the comparison register and the count register. The GPIO port of the MCU can be configured as a push-pull output mode to output the PWM waveform to the control end of the external switching device. By modifying the comparison register and count register of the TIM, the width and interval time of the discharge control pulse can be adjusted. In order to achieve optimal control of the discharge process of the energy storage capacitor, the width and interval time of the discharge control pulse need to be preset according to the discharge characteristic curve of the energy storage capacitor. The discharge characteristic curve reflects the change law of the voltage, current and other parameters of the energy storage capacitor over time, and is related to the characteristic parameters such as the capacity, equivalent series resistance (ESR) and dielectric material of the energy storage capacitor. By testing the discharge characteristics of the energy storage capacitor, its typical discharge characteristic curve can be obtained. The curve usually includes two main stages: the initial stage: the capacitor voltage drops rapidly, the discharge current is large, and the duration is short; the steady-state stage: the capacitor voltage drops slowly, the discharge current is small, and the duration is long.

[0026] S32, input the discharge control pulse into the control end of the semiconductor switch to realize the on-off control of the semiconductor switch. The semiconductor switch can be selected from MOSFET, IGBT, GTO and other devices, and its control ends are the gate, gate and control electrode respectively. When the control end voltage is higher than the threshold voltage of the device, the device is turned on; when the control end voltage is lower than the threshold voltage, the device is turned off. S33, by modulating the width of the discharge control pulse, the on-time of the semiconductor switch is changed to control the discharge process in segments; the implementation steps of segmented discharge control are as follows: determine the total discharge time T and the number of segments N, and calculate the discharge time ΔT for each segment: According to each discharge time ΔT and discharge current I, calculate each discharge charge ΔQ: ΔQ = I × ΔT. In each discharge time period, adjust the discharge pulse width tp so that each discharge charge is equal to ΔQ. Assume the discharge pulse period is T p , then t p The relationship with ΔQ is: By adjusting the discharge pulse period T p and width t p , the same amount of charge can be discharged in each discharge time period. S34, adjust the discharge duty cycle. By adjusting the time interval between adjacent discharge control pulses, the off time of the semiconductor switch can be changed, thereby adjusting the discharge duty cycle. The discharge duty cycle D is defined as the discharge pulse on time t p With period T p Ratio: D = t p / T p .

[0027] Preferably, in order to further improve the accuracy and dynamic response performance of constant current control, the change rate of the voltage across the energy storage capacitor can be introduced as feedback to adaptively adjust the discharge duty cycle. The specific method is as follows: the voltage V across the energy storage capacitor is measured by sampling the voltage sensor. c , get the voltage value V sampled k times c (k). Calculate the change in voltage between two adjacent samplings ΔV c (k):ΔV c (k) = V c (k)-V c (k-1). Calculate the voltage change rate Among them, T s is the sampling period. The voltage change rate The preset rate of change threshold By comparison, we can get the duty cycle adjustment value ΔD(k): Then ΔD(k)=-ΔD 0 ;like Then ΔD(k)=+ΔD 0 ; Otherwise, ΔD(k)=0. Where, ΔD 0 is the duty cycle adjustment step, which can be set according to the control accuracy and stability requirements. The duty cycle adjustment amount ΔD(k) is added to the reference duty cycle D 0 The new duty cycle D(k) = D 0+ΔD(k) adjusts the duty cycle of the PWM modulation signal according to the new duty cycle D(k) to control the off time of the semiconductor switch. By introducing the feedback of the voltage change rate of the energy storage capacitor, the adaptive adjustment of the discharge duty cycle can be achieved, compensating for the influence of the internal resistance of the energy storage capacitor and the load impedance change on the constant current control, and improving the robustness and adaptability of the constant current control.

[0028] S35, control the segmented constant current. In each discharge time period, by adjusting the width and time interval of the discharge control pulse, the segmented constant current control of the discharge current can be achieved. The constant current discharge process is divided into several constant current segments. In each constant current segment, the discharge current is kept constant, and a step-like discharge current waveform is formed by switching the constant current values ​​of different segments. The implementation steps of segmented constant current control are as follows: Determine the number of constant current segments M and the constant current value of each segment

[0029] I m (m=1,2,.....,M), calculate the duration of each constant current according to the total discharge charge Q and total time T In the mth constant current section, by adjusting the width t of the discharge control pulse p and time interval t i , to achieve constant current value I m Assume that the discharge control pulse period is T p , then t p and t i Need to meet: t p ×I m =t i ×(I p -I m ),T p =t p +t i ; Among them, I p is the peak discharge current, which is determined by the energy storage capacitor voltage and load impedance. The discharge current I is measured by current sensor sampling p (k), calculate the current error ΔI(k): ΔI(k) = I m -I p (k), calculate the pulse width adjustment value Δt according to the current error ΔI(k) and the PI control algorithm p (k) and time interval adjustment Δt i (k):Δt p (k) = K p ×ΔI(k)+K i ×∑ΔI(k),Δt i (k) = -Δt p (k), where K p and K iThe proportional coefficient and integral coefficient of the PI controller can be set according to the control performance requirements. p (k) and time interval adjustment Δt i (k) are superimposed on the initial value t p (0) and t i (0), and the new pulse width t p (k) and time interval t i (k):

[0030] t p (k) = t p (0)+t p (k-1), t i (k) = t i (0)+t i (k-1), according to the new pulse width t p (k) and time interval t i (k), generate PWM modulation signal to control the on and off of semiconductor switch. Repeat until the mth constant current segment ends. Switch the constant current value to the next segment I m+1 , repeat until all M constant current segments are completed. Through segmented constant current control, the discharge current can be accurately adjusted while suppressing the measurement error caused by the internal resistance of the energy storage capacitor. The stepped constant current discharge waveform is conducive to reducing the influence of the capacitor internal resistance voltage drop and load impedance changes, and improving the constant current control accuracy.

[0031] S36, discharge end judgment and control, collect the voltage value V at both ends of the energy storage capacitor in real time through the voltage sensor c (t), and convert it into a digital quantity and send it to the controller for processing. According to the calculation formula of the residual charge of the capacitor, the residual charge Q of the capacitor at the current moment is estimated r (t). The calculated residual charge Q r (t) and the preset charge threshold Q th For comparison: If Q r (t)>Q th , indicating that the residual charge of the capacitor is higher than the threshold, and the discharge process continues; if Q r (t)≤Q th, indicating that the residual charge of the capacitor has dropped below the threshold and the discharge process can be ended. When it is determined that the discharge process can be ended, the controller outputs a control signal, turns off the discharge switch, stops the discharge control pulse, and disconnects the discharge circuit. At the same time, the controller can output a discharge end mark to prompt the user or the host computer that the discharge process has been completed. After the discharge is completed, the controller can also wait for the capacitor voltage to further decay according to the set delay time to ensure that the residual charge of the capacitor is fully released and avoid the charge accumulation effect. After the delay is over, the controller outputs a discharge completion mark to prompt the system to enter the next working cycle.

[0032] Further, S36, the residual charge of the capacitor is calculated by the following formula:

[0033] Among them, t 0 is the discharge start time, in seconds (s); τ is the time constant of the energy storage capacitor, τ=R*×C 0 , R* is the equivalent resistance of the discharge circuit, in seconds (s); C 0 Represents the initial estimated value of the energy storage capacitor; is the exponential decay factor, reflecting the characteristic of exponential decay of capacitor voltage over time; ∫[t 0 ,t]I leak (t)dt is the amount of leakage charge from the start of discharge to time t, in coulombs (C), which needs to be calculated by numerical integration. The estimation of the time constant τ will affect the calculation accuracy of the residual charge of the capacitor. In practical applications, the time constant τ can be calculated by measuring the equivalent resistance R of the discharge circuit and the initial value C of the energy storage capacitor through a pre-calibrated method. It is also possible to estimate the time constant τ online during the discharge process based on the attenuation curve of the capacitor voltage to improve the estimation accuracy.

[0034] Specifically, an exponential decay factor is introduced into the formula Where τ is the time constant of the energy storage capacitor, which reflects the characteristic of the exponential decay of the capacitor voltage over time. The discharge process of the capacitor follows the exponential decay law, and the voltage decreases exponentially over time. By introducing the exponential decay factor, the dynamic characteristics of the capacitor discharge can be more accurately described and the accuracy of the residual charge calculation can be improved. The time constant τ in the formula is determined by the initial estimated value C of the energy storage capacitor. 0 and the equivalent resistance R of the discharge circuit, τ=R*×C 0 Among them, C 0 An initial estimate can be given based on the nominal value of the capacitor or prior knowledge, and R* can be obtained through measurement or theoretical calculation. By reasonably estimating the time constant, the capacitor discharge curve can be better fitted and the error in residual charge calculation can be reduced. 0 ,t]I leakThe (t)dt term calculates the amount of leakage charge from the start of discharge to the current time t. Leakage current causes the capacitor to self-discharge, affecting the estimation of the residual charge. By integrating the leakage current over time, the effect of leakage charge accumulation over time can be quantified, improving the accuracy of the residual charge calculation. The leakage current can be sampled and calculated in real time using the leakage current measurement circuit and formula described above. The initial estimate of the energy storage capacitor C is used in the formula 0 and the voltage V(t 0 ) Calculate the initial charge C 0 ×V(t 0 ). This term represents the amount of charge in the energy storage capacitor at the beginning of discharge and is the starting point for calculating the residual charge. By reasonably estimating the initial capacitance value and accurately measuring the initial voltage, an accurate initial value can be provided for the subsequent exponential decay and leakage current integration, thereby improving the overall calculation accuracy. This formula supports real-time calculation and dynamic tracking of the residual charge of the energy storage capacitor. By sampling the capacitor voltage V(t) and the leakage current I at different times t, leak (t), and substitute it into the formula for calculation, we can get the estimated value of the residual charge at any time during the capacitor discharge process. Real-time computing capability is crucial for evaluating the initiation performance and safety of electronic detonators, and helps to timely discover and diagnose potential fault risks.

[0035] Further, S5, curve fitting is performed on the voltage-time data pairs collected in multiple discharge time periods to obtain a discharge curve equation; based on the discharge curve equation, the voltage value V at the discharge termination time is calculated. 2 , including: S51, the collection and recording of the energy storage capacitor voltage. In each discharge time period, the instantaneous voltage value at both ends of the energy storage capacitor is sampled through the AD converter, and the corresponding sampling time is recorded, so that a set of voltage-time data pairs can be obtained for subsequent data processing and analysis. To select a suitable AD converter, it is required to have sufficient sampling frequency, conversion rate and resolution to meet the needs of energy storage capacitor voltage sampling. Commonly used AD converters include successive approximation type, Sigma-Delta type, dual slope type, etc., which need to be selected based on factors such as sampling speed, accuracy and cost. Assume that the maximum sampling frequency of the AD converter is f s_max , the maximum conversion rate is f s_max / N, where N is the resolution (number of bits) of the AD converter. Assume that the maximum value of the voltage change rate across the energy storage capacitor is dV c_max / dt, minimum value is dV c_min / dt. According to the range of voltage change rate, determine the adjustment range of sampling frequency and conversion rate, for example:

[0036] f s_min =k 1 ×dV c_min / dt,f s_max =k 2 ×dV c_max / dt, where k 1 and k 2 is the proportional coefficient, which is selected according to the sampling accuracy and data volume requirements. During the discharge process, the change rate dV of the voltage across the energy storage capacitor is calculated in real time. c / dt, according to the magnitude of the rate of change, at f s_min and f s_max Linearly adjust the sampling frequency f s : According to the sampling frequency f s , calculate the interval T of the conversion trigger signal t : Control the clock signal of the AD converter so that its frequency is equal to f s ; At the same time, the conversion trigger signal of the AD converter is controlled so that its interval is equal to Tt. After each sampling and conversion is completed, the controller reads the digital output of the AD converter to obtain a digital quantity representing the instantaneous voltage value. At the same time, the controller records the current clock count value or timestamp as the corresponding sampling moment. The collected voltage value and timestamp are combined into a voltage-time data pair and stored in the controller's cache or external memory. In order to save storage space, compressed storage or incremental storage can be used to record only the difference between adjacent data pairs.

[0037] S52, integration of voltage-time data and curve generation. During the discharge process of the energy storage capacitor, the voltage value at both ends of the capacitor is obtained at a certain sampling frequency through the voltage sampling circuit and the AD converter, and the corresponding timestamp is recorded at the same time to form a voltage-time data pair (t i ,V i ). For the voltage-time data pairs collected in multiple discharge time periods, they are sorted and integrated according to the timestamp. An efficient sorting algorithm such as merge sort and heap sort can be used to arrange the data pairs in chronological order. The sorted voltage-time data pairs are organized into a two-dimensional array, with the first column being the time value and the second column being the corresponding voltage value, that is: [(t 1 ,V 1 ),(t 2 ,V 2 ),......,(t i ,V i ),.....,(t n ,V m )], where n is the number of sampling points, t i and V iare the time and voltage values ​​of the i-th sampling point, respectively. Based on the voltage-time two-dimensional array, the voltage-time curve of the discharge process is generated. Mathematical tools or programming languages ​​such as MATLAB and Python can be used to plot data points in a coordinate system with time as the horizontal axis and voltage as the vertical axis, and connect adjacent data points to form a continuous curve.

[0038] S53, select a suitable discharge curve model according to the physical characteristics of the energy storage capacitor and the actual discharge conditions. The model used in this solution is:

[0039]

[0040] in, is the model parameter to be solved, which reflects the initial state of the capacitor, ESR characteristics, dielectric absorption effect, temperature characteristics, etc. Construct an error function to describe the difference between the model output and the measured data: Among them, V(t i ) is the model at time t i The output voltage, V i is the measured voltage value. Select appropriate initial values ​​for the model parameters. You can use prior knowledge such as the material properties, structural parameters, and environmental conditions of the capacitor to Make a preliminary estimate as the starting point for the least squares iteration. i is the independent variable, voltage V i As the dependent variable, the least squares method is used to iteratively optimize the parameters to minimize the error function:

[0041] You can choose the commonly used least squares algorithm such as gradient descent method, Newton method, Gauss-Newton method, Levenberg-Marquardt method, etc., and make the error function converge to the minimum value through iterative calculation to obtain the optimal parameter estimation value. Compare the discharge curve equation obtained by fitting with the measured voltage-time data, calculate the root mean square error, maximum absolute error and other evaluation indicators, and evaluate the fitting accuracy. If the accuracy meets the requirements, the discharge curve equation is established; otherwise, it is necessary to further optimize the model structure and parameter identification algorithm.

[0042] S54, obtain the time t' at which the discharge is judged to be finished in step S36. When the energy storage capacitor is discharged, the current sampling circuit and the AD converter are used to monitor the current changes at both ends of the capacitor in real time. When the current value drops to a preset threshold value (such as 1mA), the discharge process is judged to be finished and the timestamp t' is recorded. Substitute the discharge termination time t' into the discharge curve equation obtained by fitting, and calculate the voltage value V at the discharge termination time 2 . The calculated V 2The predicted accuracy of the discharge curve equation is evaluated by comparing it with the measured discharge termination voltage value. If the predicted error is within the allowable range, then V 2 It can be used as an important parameter for subsequent capacitance estimation; otherwise, the discharge curve model and parameter identification process need to be optimized to improve the prediction accuracy.

[0043] Furthermore, the discharge curve equation is as follows:

[0044]

[0045] Among them, V 0 Represents the initial voltage, which is the voltage value of the energy storage capacitor at the start of discharge t = 0, in volts (V); τ 0 It represents the time constant under ideal conditions, reflecting the discharge rate of the energy storage capacitor without ESR and dielectric absorption effect, τ 0 Determined by the initial estimated value of the energy storage capacitor and the parallel load resistance R, the relationship τ is satisfied 0 =R×C 0 ; δ τ Indicates the correction value of the time constant, reflecting the effect of ESR on the discharge time constant, in seconds (s), δ τ The size is proportional to the ESR. The larger the ESR, the larger the δ τ The larger the value, the larger the actual discharge time constant and the slower the discharge rate; κ represents the nonlinear correction coefficient of the time constant, which reflects the influence of the capacitor material characteristics and temperature on the discharge time constant. The size of κ reflects the degree of nonlinear change of the time constant over time, and the unit is seconds. -1 (s -1 ). The size of κ reflects the degree of nonlinear change of the time constant over time. The larger κ is, the stronger the nonlinearity of the time constant is. e Represents the transient response voltage, which represents the peak value of the instantaneous voltage change caused by the dielectric absorption effect, V e The size reflects the strength of the dielectric absorption effect, and its unit is volt (V). e The size of V reflects the strength of the medium absorption effect. e The larger the value, the more significant the impact on transient response; e The time constant of transient response reflects the duration of dielectric absorption effect, expressed in seconds (s). e The larger the value, the slower the transient response decays and the longer the impact on the discharge curve lasts. t Temperature-dependent voltage, indicating the voltage correction caused by temperature change, V t The size of reflects the influence of temperature on the capacitance characteristics, indicating the voltage correction caused by temperature change, and the unit is volt (V). t The size reflects the influence of temperature on the capacitance characteristics.t The larger the value, the more significant the voltage deviation caused by temperature; τ t The temperature-related time constant reflects the duration of the temperature effect; f represents the temperature-related oscillation frequency, which represents the frequency of the voltage oscillation caused by temperature changes, and the unit is Hertz (Hz). The size of f reflects the speed of temperature change. The larger f is, the faster the temperature changes and the more violent the voltage oscillation is. represents the initial phase of temperature-related oscillation, represents the initial phase of voltage oscillation caused by temperature, The size of reflects the phase relationship between the temperature change and the start of discharge, indicating the initial phase of the voltage oscillation caused by temperature, and the unit is radian (rad). The size of reflects the phase relationship between temperature change and the start of discharge.

[0046] Among them, the nonlinear time constant correction term κt is introduced to compensate for the nonlinear change of the discharge time constant caused by factors such as capacitor material characteristics and temperature. In practical applications, the discharge time constant of the energy storage capacitor may show a nonlinear change trend over time in addition to being affected by ESR. The introduction of the nonlinear correction coefficient κ can describe the nonlinear change law of the time constant over time. κt represents the nonlinear correction amount of the time constant. The larger t is, the larger the correction amount is, and the more significant the impact on the discharge process is. Introducing the temperature-related oscillation term Compensate for voltage oscillation caused by temperature changes. The characteristic parameters of energy storage capacitors, such as capacity and ESR, will change with temperature, causing oscillations in the discharge voltage curve. The temperature-dependent oscillation term is composed of the temperature-dependent voltage V t , time constant τ t , oscillation frequency f and initial phase Composition. t Reflects the voltage deviation amplitude caused by temperature change; Represents the attenuation process of temperature effect over time; represents the voltage oscillation caused by temperature, and f reflects the speed of temperature change. It reflects the phase relationship between temperature change and discharge start time.

[0047] Specifically, the first term in Eq. represents the exponential decay discharge characteristic under ideal conditions. 0 is the initial voltage, τ 0 is the ideal time constant, and the initial estimated value of the energy storage capacitor C 0 and the parallel load resistance R. This term describes the basic discharge behavior without ESR and dielectric absorption effect, and provides a benchmark for subsequent correction terms. The time constant correction δ is introduced into the equation τ , which is used to reflect the effect of ESR on the discharge time constant. ESR will cause the actual discharge time constant to deviate from the ideal value, δτ The size of reflects the influence of ESR. τ The correction term can compensate for the change in discharge rate caused by ESR and improve the accuracy of discharge curve fitting. The nonlinear correction coefficient κ of the time constant is introduced into the equation to reflect the influence of capacitor material characteristics and temperature on the discharge time constant. The discharge process of an actual capacitor may show nonlinear characteristics, and the time constant changes with time. The size of κ reflects the intensity of the nonlinear effect. By dynamically adjusting the time constant through the κt term, the shape of the actual discharge curve can be better described. The transient response voltage V is introduced into the equation e and transient response time constant τ e , used to describe the influence of dielectric absorption effect on the discharge curve. The dielectric absorption effect will cause instantaneous voltage changes in the early stage of discharge, V e The size of reflects the strength of the effect, τ e Reflects the duration of the effect. The discharge curve is corrected by the term to more accurately capture the transient response caused by the dielectric absorption effect.

[0048] Further, S7, according to the preset voltage V 1 , the corrected voltage value V 2 ', discharge duration t, calculate the energy storage capacitor C, including: according to the preset voltage V 1 , the corrected voltage value V 2 ', discharge duration t, equivalent resistance R* of the discharge circuit and equivalent series resistance r of the energy storage capacitor, calculate the theoretical value C of the energy storage capacitor C theory : Among them, ln(V 2 ' / V 1 ) is the natural logarithmic attenuation of the capacitor discharge process; (R*+r) is the total equivalent resistance of the discharge circuit, which affects the discharge time constant.

[0049] Analysis V 1 、V 2 ', t, R* and r measurement errors, calculate the maximum relative deviation δC introduced max : Where, ΔV 1 , ΔV 2 ', Δt, ΔR* and Δr are V 1 、V 2 The upper limit of measurement error of ', t, R* and r. The measurement error comprehensively reflects the accuracy, resolution, linearity, repeatability, stability and other indicators of the measurement system.

[0050] According to the maximum relative deviation δC max , calculate the minimum possible value C of the energy storage capacitor Cmin and the maximum possible value C max , forming the theoretical capacitance value C theory Confidence interval for : This interval indicates that, considering the influence of measurement error, the confidence that the true capacitance value is within the interval [C_min, C_max] is very high.

[0051] C min and C max The arithmetic mean of is taken as the measured value of the energy storage capacitance C, which can be regarded as an unbiased estimate of the capacitance value: Calculate C min and C max The half-interval length of is taken as the uncertainty ΔC, which characterizes the discreteness of the capacitance measurement result: The physical meaning of ΔC is that the probability that the true capacitance value falls within the interval [C-ΔC, C+ΔC] is very high. The smaller ΔC is, the higher the accuracy of the measurement result. The measured value of the energy storage capacitor C and the uncertainty ΔC are used as the final output to form complete capacitance measurement data, for example: C±ΔC (μF).

[0052] Among them, the corrected voltage value V 2 The calculation process of ' is as follows: During the discharge process of the energy storage capacitor, a series of voltage-time data pairs (t i ,V i ), where t i is the sampling time, V i is the voltage across the capacitor. The collected voltage-time data pair (t i ,V i ) are integrated and arranged in time sequence to form a voltage-time two-dimensional array, forming a discrete voltage-time curve. Using the least squares method, the time t i is the independent variable, voltage V i As the dependent variable, curve fitting is performed on the voltage-time curve to obtain the best fitting discharge curve equation; the discharge termination time t' is obtained, that is, the time when the discharge is judged to be finished in step S36. Substitute t' into the discharge curve equation to calculate the voltage value V at the discharge termination time 2 . Measure the leakage current during discharge and calculate the equivalent leakage charge correction voltage ΔV leak Using leakage charge to correct voltage ΔV leak The voltage value V 2 Correction is performed to obtain the corrected voltage value V 2 ':V 2 '=V 2 +ΔV leak At this point, the corrected voltage value V 2 'Calculation process. V 2'It comprehensively considers the nonlinearity and dynamic characteristics of the discharge process and the measurement error caused by the leakage current changing with temperature and voltage, and is a dynamic correction value for the voltage at the end of capacitor discharge.

[0053] Specifically, in scientific measurement and engineering applications, the measurement results usually consist of two parts: measurement value and uncertainty. The measurement value is the best estimate of the measured physical quantity, reflecting the position or size of the measurement result. Uncertainty characterizes the dispersion or credible range of the measurement result, reflecting the accuracy of the measurement value. The measurement value and uncertainty are two independent quantities and cannot be added directly. They need to be expressed separately to form a complete measurement result. The usual expression method is: measurement result = measurement value ± uncertainty. For example, if the measured value of the energy storage capacitor C is 100μF and the uncertainty ΔC is 5μF, the complete capacitance measurement data is expressed as: (100±5)μF. This expression method indicates that the true value of the measured capacitance may be in the range of 95μF to 105μF, and 100μF is the best estimate based on the current measurement conditions. Uncertainty provides a quantitative description of the credibility of the measurement result and is indispensable information for evaluating the quality of the measurement. Therefore, when the S76 outputs the complete capacitance measurement data, the measured value C and the uncertainty ΔC should be given as two independent quantities in the format of "measured value ± uncertainty" instead of adding the two together. This representation method meets the requirements of measurement science and engineering practice, and facilitates the subsequent analysis and application of the measurement results.

[0054] Compared with the prior art, the advantages of this application are:

[0055] The segmented discharge mode is adopted to realize intermittent discharge and step-like constant current control by controlling the on and off of the semiconductor switch. In each discharge time period, the discharge pulse width is adjusted to keep the discharge charge in each section consistent; by adjusting the time interval between adjacent discharge control pulses and adjusting the discharge duty cycle, the measurement error caused by the internal resistance of the energy storage capacitor is reduced and the measurement range is expanded.

[0056] After charging is completed, the charging circuit is cut off, and the leakage current is converted into a voltage signal using a current-voltage conversion circuit and a programmable gain amplifier and amplified to the AD converter range. The current-voltage conversion and programmable gain amplification can convert the tiny leakage current signal into a voltage signal linearly related to it, and automatically adjust it to the optimal range of the AD converter, making full use of the AD resolution and improving the measurement sensitivity. Multiple sampling averages and consistency checks can effectively reduce the impact of random noise and outliers, ensuring the high accuracy and reliability of leakage current measurement.

[0057] Control the semiconductor switch to discharge the energy storage capacitor in segments and intermittently, and realize segmented constant current discharge by modulating the discharge control pulse width and interval. Segmented intermittent constant current discharge can reduce the measurement error caused by the internal resistance of the capacitor. By modulating and controlling the discharge process, different discharge currents can be used at different stages, which not only shortens the discharge time, but also obtains rich voltage-time characteristic data. Real-time monitoring of the residual charge can accurately control the termination time of the discharge, avoid excessive discharge, and reduce the influence of the discharge depth on the measurement results.

[0058] During the discharge process, the sampling frequency and conversion rate of the AD converter are dynamically adjusted according to the capacitor voltage change rate to obtain voltage-time data pairs in multiple time periods. During the discharge process, the voltage change rate of the energy storage capacitor will change significantly. By adopting a dynamically adjusted sampling strategy, the sampling frequency can be increased to obtain more data during the stage of drastic voltage changes, and the sampling frequency can be reduced during the stage of gentle changes to save storage and processing resources. This method can obtain voltage-time data that fully reflects the discharge characteristics of the capacitor with a limited amount of data.

[0059] By integrating and sorting the segmented data, a complete voltage-time curve can be obtained. The least squares method is used for curve fitting to overcome the limitations of the pure theoretical model and obtain a discharge curve equation that conforms to the actual situation. During the fitting, multiple influencing factors such as ESR, dielectric absorption, and temperature effect are comprehensively considered, which can accurately characterize the true discharge characteristics of the energy storage capacitor. The voltage value at the end of discharge can be calculated based on the fitting curve equation to eliminate the uncertainty of the measured value at the end of discharge.

[0060] Energy storage capacitors will have leakage current during the discharge process, and the leakage charge will cause measurement errors. By measuring the leakage current and discharge duration, the leakage charge can be estimated more accurately. The leakage charge is equivalent to a correction voltage, which is used to correct the voltage measurement value at the end of the discharge. This can largely eliminate the influence of the leakage effect on the measurement results and improve the accuracy of capacitance measurement.

[0061] The theoretical value of the energy storage capacitor can be calculated based on the charge and discharge voltage difference and the discharge time. However, due to various error factors in the measurement process, there is a certain deviation between the theoretical value and the actual value. By analyzing the upper limit of the measurement error of each influencing parameter, the possible range of the actual value of the capacitance can be estimated, and the uncertainty of the measurement value can be given accordingly. The introduction of measurement uncertainty improves the credibility of the measurement data. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The present application will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0063] Figure 1 is an exemplary flow chart of a method for determining an energy storage capacitor in an electronic detonator according to some embodiments of the present application;

[0064] Figure 2 is an exemplary flow chart of obtaining leakage current measurement values ​​according to some embodiments of the present application;

[0065] Figure 3 is an exemplary flow chart of obtaining the voltage value V2 at the discharge termination moment according to some embodiments of the present application;

[0066] Figure 4 is an exemplary flow chart of obtaining final capacitance measurement data according to some embodiments of the present application. DETAILED DESCRIPTION

[0067] The method and system provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0068] Figure 1 The present invention is an exemplary flow chart of a method for determining an energy storage capacitor in an electronic detonator according to some embodiments of the present application. The method for determining an energy storage capacitor in an electronic detonator comprises: charging the energy storage capacitor to a preset voltage V1 through a constant current source, and monitoring the charging current and voltage at the same time. When the charging current drops below a preset threshold, the charging is judged to be completed; after the charging is completed, the charging circuit is cut off, and the leakage current Ileak of the energy storage capacitor is measured; by controlling the discharge switch, the energy storage capacitor is discharged in segments, and the discharge process is divided into multiple time periods, each of which is equal; the segmented discharge comprises: intermittent discharge by controlling the on and off of the semiconductor switch, and the discharge pulse width is controllable; in each discharge time period, according to the instantaneous voltage of the energy storage capacitor , adjust the sampling frequency and AD conversion rate; perform curve fitting on the voltage-time data pairs collected in multiple discharge time periods to obtain the discharge curve equation; calculate the voltage value V2 at the end of the discharge according to the discharge curve equation; calculate the leakage charge Qleak according to the leakage current Ileak and the discharge duration t; evenly distribute the leakage charge to the entire discharge process, which is equivalent to a correction voltage ΔV_leak; use the correction voltage ΔV_leak to correct the voltage value V2 to obtain the corrected voltage value V2'; calculate the energy storage capacitor C according to the preset voltage V1, the corrected voltage value V2', and the discharge duration t; wherein the correction voltage ΔV_leak is calculated by the following formula:

[0069]

[0070] Wherein, ΔV_leak is the correction voltage; C0 is the initial estimated value of the energy storage capacitor; T(i×Δt) and V(i×Δt) represent the average temperature and average voltage in the i-th time interval respectively; N represents dividing the continuous time t into N small areas, and the duration of each interval is Δt=t / N; T 0 and V 0 are the reference temperature and reference voltage respectively; α and β are the temperature correction coefficient and voltage correction coefficient of leakage current respectively; [1+α×(T(i×Δt)-T 0 )] and [1+β×(V(i×Δt)-V 0 )] are the temperature correction factor and voltage correction factor, respectively, which are used to compensate for the measurement error caused by the leakage current changing with temperature and voltage.

[0071] Assume that the nominal capacity of the energy storage capacitor is 100μF, the preset charging voltage V1 is 30V, and the threshold value for judging the completion of charging is 0.1mA. Charging circuit design: A high-precision programmable constant current source is selected, the output current is set to 10mA, the current accuracy is better than 0.05%, and the current noise is less than 50μA. A 10kΩ high-precision sampling resistor is connected in parallel to the output end of the constant current source to convert the charging current into a voltage signal. Voltage detection circuit: A differential op amp circuit is used to connect the two ends of the energy storage capacitor, and the amplification factor is set to 1 / 10 to convert the energy storage capacitor voltage into a single-ended voltage with a range of 0-3V, which matches the ADC range of the microcontroller. The op amp uses an ultra-low offset voltage model, and the input offset voltage is less than 10μV to ensure the voltage detection accuracy. Current monitoring circuit: A precision op amp is used to form a transimpedance amplifier circuit, which amplifies the voltage across the sampling resistor by 10 times and converts the 10mA charging current into a 1V voltage signal, which matches the ADC range of the microcontroller. The op amp uses an ultra-low bias current model with an input bias current of less than 1nA to ensure current detection sensitivity. Charging process control: The microcontroller triggers the ADC conversion regularly, the sampling frequency is set to 100Hz, and the voltage values ​​of the voltage monitoring and current monitoring channels are collected alternately, that is, the sampling frequency of each channel is 50Hz. Charging voltage judgment: When the collected voltage value of the voltage monitoring channel multiplied by the amplification factor of 10 reaches 30V, that is, the voltage across the energy storage capacitor reaches the preset value V1, and the charging completion judgment process is entered. Charging completion judgment: Continuously collect the voltage values ​​of 100 current monitoring channels and calculate their arithmetic mean. Divide the average voltage value by 10 times the resistance amplification factor and multiply it by the sampling resistance value of 10kΩ to obtain the current charging current value. When the charging current is less than or equal to 0.1mA, it is judged that the charging is completed and the constant current source output is cut off. After a period of charging, the voltage of the energy storage capacitor reaches 30V, and the charging completion judgment process is entered. The ADC values ​​of 100 current monitoring channel voltages collected continuously are: {100, 98, 101, 99, 102, 100, 98, 101, 99, 102, …}. The calculated average value is 100 mV. The corresponding actual current is: I = 100 mV ÷ 10 × 10 kΩ = 0.1 mA. The charging completion condition is met, the constant current source is cut off, and the charging stage ends. The actual capacity of the energy storage capacitor is 95μF, and the actual leakage current after charging reaches a steady state is 0.08mA. The voltage across the energy storage capacitor is: V=30V-0.08mA×10kΩ÷10=29.92V, the current monitoring channel voltage is: V_I=0.08mA×10kΩ×10=80mV, and the voltage monitoring channel voltage is: V_V=29.92V÷10=2.992V. After ADC quantization, the error between the digital quantity and the actual analog quantity is less than 0.1%, and the charging completion status can be accurately judged.

[0072] Figure 2This is an exemplary flow chart for obtaining leakage current measurement values ​​according to some embodiments of the present application. Leakage current measurement: A precision operational amplifier AD8615 is selected to form a current-voltage conversion circuit, and its feedback resistor Rf is a precision chip resistor of 1GΩ, with a resistance accuracy of 0.1% and a temperature coefficient of 25ppm / ℃. The digital potentiometer uses AD5262, whose nominal resistance is 200kΩ, resistance accuracy is 1%, and temperature drift coefficient is 35ppm / ℃. The high end of the digital potentiometer is connected to the output end of AD8615, the low end is grounded, and the slider end is connected to the in-phase input end of the amplifier AD8656. The fixed gain Gain of the amplifier AD8656 is set to 10 times, the inverting input end is grounded, and the output end is connected to the input end of the 12-bit successive approximation AD converter AD7091. The reference voltage of AD7091 is 2.5V, and the conversion result is transmitted to the programmable controller via the SPI interface. Both the digital potentiometer and the AD converter are controlled by the SPI interface of the programmable controller. The programmable controller sets the initial value of the digital potentiometer to 128, corresponding to a resistance of 100 kΩ. According to the expected range of the leakage current of the energy storage capacitor, the initial sampling frequency of the AD converter is set to 1 kHz, and 1024 sample points are collected each time.

[0073] At an ambient temperature of 25°C, the actual leakage current of the energy storage capacitor is 50nA, and the input offset current, input bias current, and input offset voltage of the operational amplifier are 20fA, 50fA, and 25μV, respectively. The voltage value after conversion by the operational amplifier is: V_amp=50nA×1GΩ=50mV, and the voltage value after amplification by the digital potentiometer and amplifier is: V_ad=50mV×(100kΩ / 200kΩ)×10=250mV, and the digital output value of the AD converter is: D_out=250mV / 2.5V×2^12=410. 1024 samples are collected continuously, and the calculated average value is 409, with a standard deviation of 1.2. The standard deviation of 10 consecutive samples is less than 2, and the sampling is considered stable. Substitute the average sampling value 409 into the leakage current calculation formula, and substitute the relevant parameters: I_leak = (409×200kΩ×(1+35ppm×0)) / (1GΩ×10×2^12)-20fA-50fA-25μV / 1GΩ=49.96nA. Repeat the measurement 10 times, and the leakage current values ​​obtained are: {49.96nA, 50.03nA, 49.98nA, 50.01nA, 49.97nA, 50.02nA, 49.99nA, 50.00nA, 49.98nA, 50.01nA}. The calculated maximum deviation is 0.07nA, which is less than the preset threshold value of 0.1nA. The arithmetic mean of the 10 measurements is taken as the final leakage current measurement result, that is: I_leak = 49.995nA.

[0074] Figure 3It is an exemplary flow chart for obtaining the voltage value V2 at the end of discharge as shown in some embodiments of the present application, and the segmented discharge measurement: the nominal capacity of the energy storage capacitor under test is 100μF, the charging voltage is 30V, and the equivalent resistance of the discharge circuit is 1kΩ. The single-chip microcomputer uses STM32F407, which has a built-in 12-bit DAC and 12-bit ADC, and the conversion rate can reach 1MSPS. The semiconductor switch uses ADG1419, whose on-resistance is less than 1Ω and the switching time is less than 10ns. The control end of ADG1419 is connected to the PWM output pin of STM32F407. The programmable amplifier uses AD8656, whose gain-bandwidth product is 24MHz, which can meet the fast buffering requirements. The input end of AD8656 is connected to the energy storage capacitor, and the output end is connected to the ADC conversion channel. The digital potentiometer uses AD5263, with a resistance range of 0-200kΩ, and forms an adjustable gain amplifier circuit with AD8656, which is controlled by the SPI interface of STM32F407. According to the discharge characteristic curve of the energy storage capacitor, the preset segmented discharge sequence is: Section 1: on-time 20μs, off-time 80μs, lasting 10ms; Section 2: on-time 50μs, off-time 150μs, lasting 20ms; Section 3: on-time 100μs, off-time 300μs, lasting 40ms; Section 4: on-time 200μs, off-time 800μs, lasting 80ms.

[0075] The constant current values ​​in each discharge segment are set as follows: 100mA for the first segment, 50mA for the second segment, 20mA for the third segment, and 5mA for the fourth segment. The STM32F407 generates the corresponding PWM waveform to control the ADG1419 to achieve segmented constant current discharge. At the same time, the voltage divider ratio of the AD5263 is adjusted, and the gain of the AD8656 is switched from the initial 1x to 2x, 5x, and 10x in sequence to ensure that the voltage of the energy storage capacitor always falls within the optimal range of the ADC. In each discharge segment, the STM32F407 continuously triggers the ADC conversion at a frequency of 100kSPS to collect the voltage value across the energy storage capacitor in real time.

[0076] The sampling voltage at the end of the first stage of discharge is: V(10ms) = 24.85V, which is substituted into the residual charge calculation formula and the relevant parameters:

[0077] Q(10ms)=100μF×24.85V×e^[-10ms / 1kΩ×100μF)]+50nA×10ms=2.214μC. Similarly, the residual charge at the end of the 2nd, 3rd, and 4th discharges is calculated as follows: Q(30ms)=1.383μC, Q(70ms)=0.672μC, Q(150ms)=0.218μC. The discharge end threshold is set to 0.2μC. When the 4th discharge is completed, the residual charge has dropped below the threshold, and the discharge is determined to be completed. The STM32F407 turns off the ADG1419 and stops the discharge control and data acquisition. During the entire segmented discharge process, the STM32F407 reads the voltage sampling value from the ADC through the SPI interface, with a cumulative sampling point count of more than 10,000, forming a high-density voltage-time data sequence, which lays a data foundation for the subsequent discharge curve fitting.

[0078] Discharge data integration: Following the setting of the above-mentioned segmented discharge measurement, the STM32F407 controls the ADC to adopt different sampling strategies in different discharge stages: During the first discharge, the voltage of the energy storage capacitor changes rapidly. In order to accurately capture the voltage drop curve, the ADC sampling frequency is set to the highest 1MSPS, and 10,000 points are continuously collected, corresponding to a sampling time of 10ms. During the second discharge, the voltage of the energy storage capacitor changes slowly, and the ADC sampling frequency is reduced to 500kSPS, and 10,000 points are continuously collected, corresponding to a sampling time of 20ms. During the third discharge, the ADC sampling frequency is further reduced to 200kSPS, and 8,000 points are continuously collected, corresponding to a sampling time of 40ms. During the fourth discharge, the ADC sampling frequency is reduced to 100kSPS, and 8,000 points are continuously collected, corresponding to a sampling time of 80ms. In each discharge segment, the STM32F407 reads the sampled data from the ADC buffer through DMA, and attaches the timestamp information to each sampling point to form a voltage-time data pair. Some data pairs of the first discharge segment are as follows: (0.00us, 29.98V), (1.00us, 29.95V), (2.00us, 29.91V), ..., (9.99ms, 24.87V), (10.00ms, 24.85V), similarly, some data pairs of the second, third, and fourth discharge segments are as follows: (10.01ms, 24.84V), (10.02ms, 24.83V), ..., (29.99ms, 20.77V), (30.00ms, 20.76V), (30.01ms, 20 .75V), (30.03ms, 20.74V), ..., (69.98ms, 15.42V), (70.00ms, 15.41V), (70.02ms, 15.40V), (70.06ms, 15.39V), ..., (149.94ms, 7.78V), (150.00ms, 7.77V), STM32F407 concatenates the data pairs of the four discharge segments in chronological order to form a complete voltage-time two-dimensional array with a total length of 36,000, covering the entire 150ms discharge process. In order to intuitively display the changing trend of the discharge curve, STM32F407 uses the floating-point math library to interpolate the voltage-time data pairs in the two-dimensional array to obtain an equidistant scattered sequence with an interval of 10us, and the length is extended to 15,000.Some data pairs after interpolation are as follows: (0.00us, 29.98V), (10.00us, 29.86V), (20.00us, 29.74V), ..., (149.99ms, 7.77V), (150.00ms, 7.77V). STM32F407 transmits the interpolated voltage-time series to the host computer through the UART interface, and uses data analysis tools such as MATLAB or Python to draw the voltage-time curve.

[0079] Based on the results of the above discharge data integration, the interpolated voltage-time series is fitted using the Curve Fitting tool of MATLAB. Select Custom Equation as the fitting equation and enter the discharge curve equation into the expression box:

[0080] Set the initial values ​​and boundary conditions of the fitting parameters as follows: V 0 =30, boundary [28, 32], τ 0 =0.1, boundary [0.05, 0.2], δτ =0, boundary [-0.02, 0.02], κ =0, boundary [-e- 3 ,e- 3 ],V e =0, boundary [-1, 1], τ e =e -3 , the boundary [e- 4 ,e- 2 ],V t =0, boundary [-0.1, 0.1], τ t =e -2 , boundary [e- 3 ,e- 1 ]f=e 3 , the boundary [e 2 ,e 4 ], Boundary [-π,π]. Click the "Fit" button to start fitting, and the fitting results are as follows: V 0 =30.02, τ 0 =0.114, δτ=-0.005, κ=-2.7e -4 , V e =0.18V, τ e =3.6e -3 , V t =0.03, τ t =0.024, f=732,

[0081] Figure 4This is an exemplary flow chart for obtaining the final capacitance measurement data according to some embodiments of the present application. According to the leakage current measurement result, the average leakage current is 50nA. STM32F407 substitutes it into the discharge curve equation after fitting, and numerically integrates and solves the corresponding correction voltage:

[0082]

[0083] , the resolution voltage of ADC is: V_res = 2.5V / 2^12 = 610uV, obviously, ΔV leak <<V_res, so it is determined that the discharge has ended at 150ms. STM32F407 substitutes the discharge termination time t'=150ms into the fitted discharge curve equation and calculates the termination voltage: V(150ms)=5.64V.

[0084] According to the results of the discharge curve fitting, the following key parameters are obtained: charging voltage V1 = 30V, discharge termination time t' = 150ms, discharge termination voltage V2' = 5.64V, discharge circuit equivalent resistance R* = 1kΩ, energy storage capacitor equivalent series resistance r = 10Ω, and the theoretical value of energy storage capacitor capacity is calculated by substituting it into the capacitor discharge formula: C_theory = -150ms / [ln(5.64V / 30V)×(1kΩ+10Ω)] = 97.8μF. Considering the influence of measurement error, The upper limits of the measurement errors of the parameters are as follows: ΔV1=0.1V, ΔV2'=0.05V, Δt=1ms, ΔR*=10Ω, Δr=1Ω. Substituting into the relative deviation calculation formula, we get the maximum relative deviation: δC_max=|(0.1V / 30V)+(0.05V / 5.64V)+(1ms / 150ms)+(10Ω / 1kΩ)+(1Ω / 10Ω)|=0.0033+0.0089+0.0067+0.01+0.1=0.129=12.9%.

[0085] Based on this, the minimum and maximum values ​​of the energy storage capacitor capacity are calculated: C_min=97.8μF×(1-12.9%)=85.2μF, C_max=97.8μF×(1+12.9%)=110.4μF, and the average value of the minimum and maximum values ​​is taken as the measured value of the energy storage capacitor capacity: C=(85.2μF+110.4μF) / 2=97.8μF. The difference between the minimum and maximum values ​​is calculated as the uncertainty of the measurement result: ΔC=(110.4μF-85.2μF) / 2=12.6μF. Therefore, the capacity measurement result of the energy storage capacitor is: (97.8±12.6)μF. To further evaluate the reliability of the measurement results, Monte Carlo simulation was performed using MATLAB. Each error source obeys the following distribution: voltage measurement error: normal distribution N(0, 0.02^2), time measurement error: normal distribution N(0, 0.5^2), resistance measurement error: uniform distribution U(-5, 5). 10,000 groups of error samples were randomly generated and substituted into the capacitance calculation formula. From the simulation results, it can be concluded that the capacitance presents an approximate normal distribution, with a mean of 97.6μF and a standard deviation of 6.3μF, which is close to the theoretical calculation results. Taking the standard deviation of the simulation sample as the reference value of the measurement uncertainty, the final measurement result is expressed as: (97.8±6.3)μF.

[0086] The nominal value of the capacitance of this type of capacitor is 100μF, and the allowable deviation is ±20%. The qualified range of capacitance is [80μF, 120μF]. Comparing the measurement results with this range, it can be determined whether the measured capacitor is qualified. After 10 repeated measurements, the measurement results of the capacitance are as follows: 98.2μF, 96.5μF, 97.9μF, 99.1μF, 97.4μF, 98.6μF, 96.8μF, 97.3μF, 98.8μF, 97.6μF; calculating the arithmetic mean, the measured value of the capacitance is: 97.8μF; taking the average of the 10 measurement uncertainties, the measurement uncertainty is: 6.5μF; so far, the final measurement result of the capacitance is: (97.8±6.5)μF, the error is less than 5% of the nominal value, and the uncertainty is less than 10%, which meets the requirements of accurate measurement. The above measurement results are applied to the screening of electronic detonators. If the capacitance of a sample is found to be out of the range of [80μF, 120μF], or the measurement uncertainty is greater than 20μF, the sample is judged to be unqualified and shall be discarded.

Claims

1. A method for determining an energy storage capacitor in an electronic detonator, comprising: S1, charging the energy storage capacitor to a preset voltage V1 through a constant current source, while monitoring the charging current and voltage. When the charging current drops below a preset threshold, charging is considered complete; S2, after charging is completed, cut off the charging circuit and measure the leakage current V of the energy storage capacitor leak ; S3, by controlling the discharge switch, the energy storage capacitor is discharged in segments, and the discharge process is divided into multiple time periods, each of which is equal; the segmented discharge includes: by controlling the on and off of the semiconductor switch, intermittent discharge, and the discharge pulse width is controllable; S4, in each discharge time period, adjusting the sampling frequency and the AD conversion rate according to the instantaneous voltage of the energy storage capacitor; S5, performing curve fitting on the voltage-time data pairs collected in multiple discharge time periods to obtain a discharge curve equation; and calculating the voltage value V2 at the discharge termination time according to the discharge curve equation; S6, according to the leakage current I leak and discharge duration t, calculate the leakage charge Q leak ; Distribute the leakage charge evenly throughout the discharge process, which is equivalent to a correction voltage ΔV leak ; Using the correction voltage ΔV leak Correcting the voltage value V2 to obtain a corrected voltage value V2'; S7, calculating the energy storage capacitor C according to the preset voltage V1, the corrected voltage value V2', and the discharge duration t; Among them, S2, after charging is completed, cuts off the charging circuit and measures the leakage current V of the energy storage capacitor leak ,include: S21, connect the energy storage capacitor to the inverting output terminal of the operational amplifier to form a current-voltage conversion circuit; the non-inverting input terminal of the operational amplifier is grounded, and the output terminal is connected to the feedback resistor R f , converting the leakage current into a voltage signal; S22, inputting the voltage signal output by the operational amplifier into an amplifier with programmable gain, adjusting the gain of the amplifier through a digital potentiometer, and amplifying voltage signals of different magnitudes to within the range of the AD converter; wherein the digital potentiometer is connected to a programmable controller through an SPI interface, and the resistance value of the digital potentiometer is controlled by the programmable controller; S23, inputting the amplified voltage signal into an AD converter for sampling to obtain a digital value; wherein the sampling frequency and the number of sampling points of the AD converter are adjusted according to the change rate of the leakage current; S24, performing arithmetic averaging on the multiple digital quantities obtained by sampling to obtain an average sampling value; calculating the standard deviation of the sampling value, and when multiple consecutive standard deviations are all less than a threshold value, determining that the sampling is stable; S25, converting the average sampling value into a measurement value linearly related to the leakage current according to the feedback resistance of the operational amplifier, the resistance value of the digital potentiometer, the fixed gain of the amplifier and the range of the AD converter; S26, repeating steps S23 to S25, measuring the leakage current multiple times, and performing consistency check. When the maximum deviation of the consecutive multiple measurement results is less than the threshold, the arithmetic mean is taken as the final leakage current measurement value I leak ; Correction voltage ΔV leak , calculated by the following formula: Where, ΔV leak is the correction voltage; C0 is the initial estimated value of the energy storage capacitor; T(i×Δt) and V(i×Δt) represent the average temperature and average voltage in the i-th time interval respectively; N represents the division of the continuous time t into N small areas, and the duration of each interval is Δt=t / N; T0 and V0 are the reference temperature and reference voltage respectively; a and β are the temperature correction coefficient and voltage correction coefficient of the leakage current respectively; [1+α×(T(i×Δt)-T0)] and [1+β×(V(i×Δt)-V0)] are the temperature correction factor and voltage correction factor respectively, which are used to compensate for the measurement error caused by the leakage current changing with temperature and voltage; S25, convert the average sampled value into a measurement value linearly related to the leakage current, using the following formula: Among them, I leak Represents the leakage current measurement value; V out Indicates the average sampling value of the AD converter, that is, the digital output value; D N It represents the nominal resistance of the digital potentiometer at the reference temperature; ξ represents the temperature drift coefficient of the digital potentiometer, which represents the relative rate of change of the digital potentiometer resistance with temperature; ΔT is the difference between the actual operating temperature of the digital potentiometer and the reference temperature; R f Represents the operational amplifier feedback resistor value; G ain represents the fixed gain of the amplifier; n is the number of conversion bits of the AD converter; I os It represents the input offset current of the operational amplifier, which represents the leakage current of the operational amplifier at the input end; I b Represents the input bias current of the operational amplifier, which means the DC current that the input stage of the operational amplifier needs to obtain from the signal source; V os It represents the input offset voltage of the operational amplifier, which represents the DC voltage difference at the input terminal of the operational amplifier.

2. The method for determining the energy storage capacitor in the electronic detonator according to claim 1, characterized in that: S3, by controlling the on and off of the semiconductor switch, performs intermittent discharge, including: S31, generating a series of discharge control pulses through a programmable controller, wherein the width and interval time of the discharge control pulses are adjustable; wherein the width and interval time of the discharge control pulses are preset according to the discharge characteristic curve of the energy storage capacitor; S32, inputting a discharge control pulse into a control terminal of a semiconductor switch to control the on and off of the semiconductor switch; S33, by modulating the width of the discharge control pulse, changing the on-time of the semiconductor switch, and controlling the discharge process in sections; in each discharge time period, by adjusting the discharge pulse width, the amount of discharge charge in each section is kept consistent; S34, adjusting the time interval between adjacent discharge control pulses to change the off time of the semiconductor switch and adjust the discharge duty cycle; adjusting the discharge duty cycle according to the rate of change of the voltage across the energy storage capacitor; S35, in each discharge time period, by adjusting the width and time interval of the discharge control pulse, the discharge current is controlled in sections; the constant current values ​​of each section are switched in sequence to form a step-like discharge current, so as to reduce the measurement error caused by the internal resistance of the energy storage capacitor; S36, during the discharge process, the voltage value across the energy storage capacitor is collected in real time to calculate the residual charge of the capacitor; when the charge drops below a preset threshold, the discharge is judged to be complete, the discharge switch is turned off, and the discharge control is stopped.

3. The method for determining the energy storage capacitor in the electronic detonator according to claim 2, characterized in that: S36, calculate the residual charge of the capacitor using the following formula: Wherein, t0 is the time when discharge starts; τ is the time constant of the energy storage capacitor, T=R*×C0, R* is the equivalent resistance of the discharge circuit; C0 represents the initial estimated value of the energy storage capacitor; is the exponential decay factor, reflecting the characteristic of exponential decay of capacitor voltage over time; ∫[t0,t]I leak (t)dt is the amount of leakage charge from the start of discharge to time t.

4. The method for determining the energy storage capacitor in the electronic detonator according to claim 2, characterized in that: S5, performing curve fitting on the voltage-time data pairs collected in multiple discharge time periods to obtain a discharge curve equation; According to the discharge curve equation, the voltage value V2 at the end of discharge is calculated, including: S51, in each discharge time period, collect the instantaneous voltage value across the energy storage capacitor through the AD converter, and record the corresponding sampling time to obtain a set of voltage-time data pairs; wherein the sampling frequency and conversion rate of the AD converter are adjusted according to the change rate of the voltage across the energy storage capacitor, and the sampling frequency and conversion rate are adjusted by controlling the clock signal and conversion trigger signal of the AD converter; S52, integrating the voltage-time data pairs collected in multiple discharge time periods, arranging them in time sequence to form a voltage-time two-dimensional array, and obtaining a voltage-time curve of the discharge process; S53, according to the discharge characteristics of the energy storage capacitor, using the least square method, with time as the independent variable and voltage as the dependent variable, curve fitting is performed on the voltage-time curve to obtain a discharge curve equation; S54, obtaining the time t' at which the discharge is judged to end in step S36, substituting t' as the discharge end time into the discharge curve equation, and calculating the voltage value V2 at the discharge end time.

5. The method for determining the energy storage capacitor in the electronic detonator according to claim 4, characterized in that: The discharge curve equation is as follows: Wherein, V0 represents the initial voltage, which means the voltage value of the energy storage capacitor at the start of discharge t=0; T0 represents the time constant under ideal conditions, T0=R×C0; δ T Indicates the correction value of the time constant; K indicates the nonlinear correction coefficient of the time constant; V e Represents the transient response voltage; T e Represents the time constant of transient response; V t Temperature dependent voltage; T t The temperature-dependent time constant; f represents the temperature-dependent oscillation frequency; represents the initial phase of temperature-dependent oscillation.

6. The method for determining the energy storage capacitor in an electronic detonator according to any one of claims 1 to 5, characterized in that: S7, calculating the energy storage capacitor C according to the preset voltage V1, the corrected voltage value V2', and the discharge duration t, including: S71, calculate the theoretical value C of the energy storage capacitor C according to the preset voltage V1, the corrected voltage value V2', and the discharge duration t theory ; S72, calculate the maximum relative deviation δC introduced by the measurement error max ; S73, according to the maximum relative deviation δC max , calculate the minimum value of the energy storage capacitor C min and the maximum value C max : C min =C theory ×(1-δC max ) C max =C theory ×(1+δC max ) S74, calculate the minimum value C min and the maximum value C max The average value of the energy storage capacitor C is: S75, calculate C min and C max Uncertainty ΔC: S76, outputting the measured value of the energy storage capacitor C and the uncertainty ΔC as the final result to form complete capacitance measurement data.

7. The method for determining the energy storage capacitor in the electronic detonator according to claim 6, characterized in that: Calculate the theoretical value of the energy storage capacitor C theory , through the following formula: Among them, R* is the equivalent resistance of the discharge circuit, and r is the equivalent series resistance of the energy storage capacitor.

8. The method for determining the energy storage capacitor in the electronic detonator according to claim 7, characterized in that: Calculate the maximum relative deviation δC introduced by the measurement error max : Among them, ΔV1, ΔV2', Δt, ΔR* and Δr are the upper limits of the measurement errors of V1, V2', t, R* and r respectively.

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