High-frequency composite pulsed electron beam welding beam current feedback control circuit, method and system

Abstract

This invention relates to the field of electron beam welding technology, and discloses a high-frequency composite pulse electron beam welding beam current feedback control circuit, method, and system. The control circuit includes a sampling unit, a data processing unit, and a power supply unit, with the data processing unit connected to both the sampling unit and the power supply unit. The sampling unit collects the current signal of the electron beam and the voltage signal of the power supply unit to obtain a sampling signal. The data processing unit performs calculations based on the sampling signal and outputs a voltage control signal, which is used to adjust the output voltage of the power supply unit. The power supply unit adjusts its low-voltage output according to the voltage control signal output by the data processing unit. The power supply unit inverts and converts the low-voltage output to output a high-voltage output, which is used to control the electron beam. This invention solves the problem of inaccurate control during electron beam welding, making the control of the electron beam more precise.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of electron beam welding technology, and particularly to a high-frequency composite pulse electron beam welding beam current feedback control circuit, method and system. Background Technology

[0002] In the field of welding technology, high-frequency composite pulsed electron beam welding is an advanced welding technique that combines the characteristics of high-frequency and low-frequency pulses to achieve more precise control over the welding process, thereby improving welding quality and efficiency. In electron beam additive manufacturing, this composite pulsed electron beam welding technology has a significant impact on welding quality and efficiency. Low-frequency pulses are primarily used to provide a stable melting rate and heat input, while high-frequency pulses are used to more precisely control droplet transfer and the dynamic behavior of the molten pool.

[0003] In low-frequency pulsed electron beam welding systems below 1kHz, current sampling in the high-voltage accelerating power supply circuit within the high-voltage tank is commonly used for beam current feedback control. Other designs use output voltage sampling from the bias grid within the high-voltage tank, estimating the beam current through a computational model for further feedback control. However, because the high-voltage tank requires a high-voltage isolation transformer for energy transmission and high-voltage isolation, the inverter AC voltage on the transformer generates significant electromagnetic and conducted interference to signal measurements when higher pulse frequencies are output, leading to measurement inaccuracies.

[0004] In constant current electron beam feedback systems, analog PID controllers are used to change the bias voltage, thereby effectively controlling the beam current. However, in conventional pulsed electron beam welding, if analog PID control is used, the feedback delay time significantly affects the upper limit of the output pulse frequency. Therefore, at higher output pulse frequencies, the current practice is mostly to use a "beam-bias lookup table method" for closed-loop control of the bias output and open-loop control of the beam current adjustment. This method is also known as beam coarse adjustment. However, as the beam pulse frequency increases, the influence of parasitic parameters in the circuit becomes greater, and the deviation between the actual output beam base peak value and the set beam base peak value continuously increases. Summary of the Invention

[0005] The purpose of this invention is to provide at least a high-frequency composite pulsed electron beam welding beam current feedback control circuit, method, and system, which can at least solve the technical problem that the deviation between the actual output beam current base peak value and the set beam current base peak value increases with the increase of beam current pulse, and at least achieve the technical effect of reducing the deviation between the actual output beam current base peak value and the set beam current base peak value.

[0006] To address the aforementioned technical problems, at least one embodiment of this application provides a high-frequency composite pulse electron beam welding beam current feedback control circuit, including a sampling unit, a data processing unit, and a power supply unit. The data processing unit is connected to both the sampling unit and the power supply unit. The sampling unit is used to acquire the current signal of the electron beam and the voltage signal of the power supply unit, and amplifies the current signal and voltage signal respectively to obtain a sampled current signal and a sampled voltage signal. The data processing unit performs calculations based on the sampled current signal and the sampled voltage signal, and outputs a voltage control signal to adjust the output voltage of the power supply unit. The power supply unit adjusts the output voltage according to the output voltage control signal to control the electron beam.

[0007] At least one embodiment of this application also provides a high-frequency composite pulsed electron beam welding beam current feedback control method, comprising: setting pulsed electron beam parameters; outputting first low voltage and second low voltage parameters according to a beam current-bias voltage lookup table; sampling the first low voltage, second low voltage, and electron beam current signals; shaping the collected data to obtain sampled data; statistically analyzing the distribution range of the sampled data; calculating the second integral value of the sampled data within one operation cycle; calculating the first integral value of the sampled data for each high-frequency pulsed beam cycle within one operation cycle to obtain effective integral values; obtaining the maximum effective integral value and the minimum effective integral value within one operation cycle; calculating an estimated beam parameter value based on the maximum effective integral value, the data distribution range corresponding to the maximum effective integral value, the minimum effective integral value, the data distribution range corresponding to the minimum effective integral value, and the high-frequency pulse parameters; calculating the third integral of the estimated beam parameter value; when the first deviation rate between the third integral and the second integral meets the requirements, the estimated beam parameter value is valid; using the valid estimated beam parameter value for calculation, adjusting the output of the first low voltage and the second low voltage.

[0008] At least one embodiment of this application also provides a high-frequency composite pulse electron beam welding beam current feedback control system, including the high-frequency composite pulse electron beam welding beam current feedback control circuit and an electron beam generating device as described above. The electron beam generating device is connected to a power supply unit and a sampling unit, and is used to generate an electron beam acting on the workpiece according to the output voltage of the power supply unit. The sampling unit is used to collect the current signal of the electron beam current and the voltage signal of the power supply unit, convert the electron beam current signal into a voltage for acquisition, and divide and amplify the acquired voltage signal, and convert the amplified voltage signal back into a current to obtain a sampled current signal. The data processing unit, based on the sampled current signal and the sampled power supply voltage signal, adopts the high-frequency composite pulse electron beam welding beam current feedback control method as described above, and outputs a voltage control signal to control the output voltage of the power supply unit.

[0009] The high-frequency composite pulsed electron beam welding beam feedback control circuit, method, and system provided in the embodiments of this application, compared with the prior art, amplify and integrate the sampled data to obtain effective beam parameter estimates, and then perform PID calculations based on the effective beam parameter estimates to output control signals to control the output of the power supply unit, thereby solving the beam feedback control problem and realizing precise beam control.

[0010] In addition, the sampling unit includes a current sampling module and a voltage sampling module. The current sampling module is used to collect the current signal of the electron beam, and the voltage sampling module is used to collect the voltage signal of the power supply unit. The sampling data is collected separately and used as a feedback basis to ensure the accuracy of feedback control.

[0011] In addition, the current sampling module includes a sampling circuit, an amplification circuit, and a voltage-to-current conversion circuit connected in sequence. The sampling circuit is used to acquire the current signal of the electron beam to obtain a acquired voltage signal. The amplification circuit is used to amplify the acquired voltage signal to obtain an amplified voltage signal. The voltage-to-current conversion circuit is used to convert the amplified voltage signal into a sampled current signal and transmit it to the data processing unit. Amplifying and converting the current sampling data of the beam and outputting it as current extends the signal transmission distance and reduces signal loss during transmission.

[0012] In addition, the sampling circuit includes a sampling sub-circuit and a voltage divider sub-circuit connected in parallel. The sampling sub-circuit is used to acquire the beam signal acting on the workpiece, and the voltage divider sub-circuit is used to divide and filter the sampled beam signal to obtain the acquired voltage signal. The use of the voltage divider circuit reduces the amplitude of the input signal.

[0013] Furthermore, the amplification circuit includes: a first amplification sub-circuit, a voltage follower sub-circuit, a second amplification sub-circuit, and a third amplification sub-circuit connected in sequence. The first amplification sub-circuit is used to amplify the acquired voltage signal for the first time; the voltage follower sub-circuit is used to follow the first amplification result of the first amplification sub-circuit; the second amplification sub-circuit is used for impedance isolation and amplification; and the third amplification sub-circuit is used for a third amplification to obtain the amplified voltage signal. After amplification and isolation processing, differential-mode noise in the signal is reduced, preventing high-voltage faults from damaging subsequent circuits.

[0014] In addition, the first amplification sub-circuit includes a high-speed instrumentation amplifier, which reduces differential-mode noise in the signal; the second amplification sub-circuit includes a high-speed isolation amplifier; and the third amplification sub-circuit includes a differential amplifier, which prevents high-voltage faults from damaging subsequent circuits.

[0015] In addition, the voltage-to-current conversion circuit includes a current transmitter, which amplifies the amplified voltage signal output by the amplifier circuit again and converts the amplified result into a current signal for output, thereby extending the transmission distance and reducing signal loss.

[0016] In addition, the data processing unit includes a current-to-voltage conversion circuit, an analog-to-digital conversion circuit, and a control circuit connected in sequence. The current-to-voltage conversion circuit converts the current signal from the sampling unit into a voltage signal and samples it to obtain an analog voltage signal. The analog-to-digital conversion circuit performs analog-to-digital conversion on the analog voltage signal to obtain a digital sampled current signal. The control circuit performs calculations based on the digital sampled current signal and the sampled voltage signal from the power supply unit to obtain a voltage control signal, which is then transmitted to the power supply unit. By processing the sampled data and outputting effective beam current parameter estimates for feedback control, the accuracy of beam current control is improved.

[0017] Furthermore, the power supply unit includes a first high-voltage generating circuit and a second high-voltage generating circuit. One output terminal of the first high-voltage generating circuit is connected to one output terminal of the second high-voltage generating circuit. The other output terminals of the first and second high-voltage generating circuits serve as output terminals of the power supply unit. The first high-voltage generating circuit is connected to a sampling unit and a data processing unit, respectively. The second high-voltage generating circuit is also connected to both the sampling unit and the data processing unit. The sampling unit samples a first low-voltage signal from the first high-voltage generating circuit and a second low-voltage signal from the second high-voltage generating circuit, respectively. The data processing unit controls the outputs of the first and second high-voltage generating circuits based on the sampled first and second low-voltage signals and the sampled current signal. Adjusting the low-voltage output to control the high-voltage output reduces the difficulty of feedback control.

[0018] Furthermore, the first and second high-voltage generating circuits have the same structure, including: a low-frequency pulse bias power supply circuit, an inverter circuit, an isolation transformer, and a high-frequency pulse bias power supply high-voltage circuit connected in sequence. The low-frequency pulse bias power supply circuit outputs low-voltage DC power, the inverter circuit converts the low-voltage DC power into first AC power, the isolation transformer converts the first AC power into second AC power, and the high-frequency pulse bias power supply high-voltage circuit outputs high voltage based on the second AC power. By transforming low voltage into high voltage, the purpose of high-voltage output is achieved.

[0019] The high-frequency composite pulsed electron beam welding beam current feedback control method of this application includes: using a sampling unit to acquire the current signal of the electron beam and the low-voltage signal of the power supply unit, and amplifying the sampled current signal and the sampled voltage signal respectively to obtain sampled data, wherein the sampled data includes the sampled current signal of the electron beam and the sampled voltage signal of the power supply unit; using a data processing unit to set the pulsed electron beam parameters, and outputting a voltage control signal according to the beam current-bias voltage lookup table to control the low-voltage output of the power supply unit; and using the data processing unit to perform calculation processing on the sampled data, adjusting the voltage control signal, and then adjusting the low-voltage output of the power supply unit based on the adjusted voltage control signal; the power supply unit is controlled by the voltage control signal, adjusts the low-voltage output, and outputs a high voltage after inverting the low-voltage output; and controlling the electron beam based on the high voltage output of the power supply unit.

[0020] The method of this application first starts the low-voltage output using a beam bias reference table, then the sampling unit samples and processes the data, and the data processing unit adjusts the output of the power supply unit based on the sampled data, thereby realizing feedback control of the beam and improving the accuracy of beam control.

[0021] Furthermore, the processing and calculation of the sampled data specifically includes: statistically analyzing the distribution range of the sampled data; calculating the second integral value of the sampled data within one operation cycle; calculating the first integral value of the sampled data for each high-frequency pulse beam cycle within one operation cycle to obtain effective integral values, and obtaining the maximum and minimum effective integral values ​​within one operation cycle; calculating the estimated beam parameters based on the maximum effective integral value, the data distribution range corresponding to the maximum effective integral value, the minimum effective integral value, the data distribution range corresponding to the minimum effective integral value, and the high-frequency pulse parameters; calculating the third integral of the estimated beam parameters; when the first deviation rate between the third integral and the second integral meets the requirements, the estimated beam parameters are considered valid. The valid estimated beam parameters are used for calculation, and a voltage control signal is output to the power supply unit to adjust the low-voltage output of the power supply unit. Actual sampled data, due to factors such as delay and interference, cannot be accurately and promptly used for feedback control. This method improves the accuracy of feedback control by processing the sampled data and then performing integral calculations to obtain effective estimated beam parameters.

[0022] In addition, the process of processing the sampled data using the data processing unit further includes: calculating a second deviation rate between the estimated beam parameter value and the set value within a second set time period; and updating the beam-bias comparison table when the second deviation rate is less than a second deviation rate threshold. Updating the comparison table based on the estimated beam parameter value improves the accuracy of the comparison table and allows for more precise control of the output in the next step.

[0023] Furthermore, calculating the maximum and minimum effective integral values ​​within a computational cycle includes: calculating the first integral value of the sampled data for each high-frequency pulse beam cycle within a computational cycle; marking the first integral value of the current cycle as an effective integral value when the rate of change between the first integral value of the current cycle and the first integral value of the previous cycle is greater than a set value; and obtaining the maximum and minimum effective integral values ​​from the effective integral value dataset of a computational cycle. Only the maximum and minimum values ​​are retained for the high-frequency pulses within the computational cycle; the maximum value corresponds to the high frequency, and the minimum value corresponds to the low frequency, ensuring the data integrity for both high and low frequency computations.

[0024] In addition, the calculation of the estimated beam parameters includes: obtaining a beam value from the data distribution interval corresponding to the maximum effective integral value, and combining the maximum effective integral value and the set beam parameters to calculate a first set of estimated beam parameters, including the estimated peak current value. I p Peak-to-peak current estimation value I pp A beam parameter is obtained from the data distribution interval corresponding to the minimum effective integral value. Combined with the minimum effective integral value and the set beam parameter, a second set of estimated beam parameter values ​​is calculated, including the estimated base current value. I b Estimated peak current of the base stack I bp By performing integration, signal glitches are smoothed out, and timing delays are ignored, thus ensuring data accuracy.

[0025] In addition, obtaining a beam value from the data distribution interval includes: statistically analyzing the sampled data using a distribution histogram, and selecting a value from the interval with the largest amount of data in the distribution histogram as a beam value. Using a histogram provides a more intuitive way to obtain the beam value, and selecting a value from the interval with the largest amount of data as the beam value ensures the probability of the beam value occurring and improves the reliability of the data.

[0026] In addition, the calculated peak-to-peak current estimate I pp This includes: obtaining a value as a beam value from the interval with the most sampled values ​​in the distribution histogram of the sampled data corresponding to the maximum effective integral. I 1. Assuming the beam current value I 1 represents the estimated peak current. I p The peak-to-peak current estimate is then calculated using the following formula. I pp :

[0027] I pp = ( SH，MAX f H - I 1(1 - d H )) / d H ; (1);

[0028] Based on peak current estimation I p Peak-to-peak current estimation value I pp The two values ​​are compared to determine the final peak current estimate. I p Or peak-to-peak current estimation value I pp ;

[0029] like( S H，MAX f H - I 1(1 - d H )) / d H Greater than or equal to I 1. Then the assumption is true:

[0030] I p = I 1. I pp = ( S H，MAX f H - I 1(1 - d H )) / d H (2);

[0031] like( S H，MAX f H - I 1(1 - d H )) / d H Less than I 1. Then the assumption is not true:

[0032] I pp = I 1. I p = ( SH，MAX f H - I 1 d H ) / (1 - d H (3); where S H，MA This represents the maximum effective integral. f H Indicates the frequency of a high-frequency pulse. d H This indicates the duty cycle of the high-frequency pulse.

[0033] In addition, the calculated base stack peak current estimate I bp This includes: obtaining a value as a beam value from the interval with the most sampled values ​​in the distribution histogram of the sampled data corresponding to the minimum effective integral. I 1. Assuming the beam current value I 1 represents the estimated base current value. I b The estimated value of the base stack peak current is then calculated using the following formula. I bp :

[0034] I bp = ( S H，MIN f H - I 1(1 - d H )) / d H , (4;

[0035] Based on the reference current estimate I b Estimated peak current of the base stack I bp The two values ​​are compared to determine the final reference current estimate. I b Or the estimated peak current of the base stack I bp ;

[0036] like( S H，MIN f H - I 1(1 - d H )) / d H Greater than or equal to I 1. Then the assumption is true:

[0037] I b = I 1. I bp = ( S H，MIN f H - I 1(1 - d H )) / d H ;(5);

[0038] like( S H，MIN f H - I 1(1 - d H )) / d H Less than I 1. Then the assumption is not true:

[0039] I bp = I 1. I b = ( S H，MIN f H - I 1 d H ) / (1 - d H ) ;(6;In the formula, S H，MIN This represents the minimum effective integral. f H Indicates the frequency of a high-frequency pulse. d H This indicates the duty cycle of the high-frequency pulse.

[0040] Values ​​are taken from the histogram, and calculations are performed in conjunction with the set parameters. Based on the relationship between the peak value and the base value, estimated beam parameters are obtained for subsequent feedback control, avoiding the inability to perform timely feedback control due to delays in actual sampling data.

[0041] Furthermore, the requirement that the beam parameter estimation value is valid when the first deviation rate between the third integral and the second integral meets the requirements includes: calculating the third integral of the beam parameter estimation value based on the first set of beam parameter estimation values ​​and the second set of beam parameter estimation values; calculating the first deviation rate between the third integral value and the second integral value; if the first deviation rate is less than the first deviation rate threshold, the beam parameter estimation value is valid; if the first deviation rate is greater than or equal to the first deviation rate threshold, recalculating the first integral value, the first set of beam parameter estimation values, the second set of beam parameter estimation values, and the third integral of the beam parameter estimation values ​​for each high-frequency pulse beam cycle within one operation cycle to obtain a valid beam parameter estimation value. Evaluating the beam parameter estimation value ensures the accuracy of the estimation value.

[0042] In addition, after setting the pulsed electron beam parameters and outputting the first and second low-voltage parameters according to the beam-bias voltage lookup table, the first and second low-voltage parameters are sampled. Based on the sampled first and second low-voltage parameters, the first calculation is performed, and a voltage control signal is output to control the output of the first and second low-voltage parameters. By controlling the low-voltage output according to the lookup table, the output is coarsely adjusted to improve the output accuracy.

[0043] Furthermore, the low-voltage output includes a first low-voltage output and a second low-voltage output. The process of processing the sampled data to adjust the voltage control signal and thus adjust the low-voltage output of the power supply unit includes: sampling the first low-voltage and the second low-voltage; performing calculations based on the sampled first low-voltage and second low-voltage; outputting voltage control signals to adjust the outputs of the first low-voltage and the second low-voltage, respectively. Using dual-voltage superposition expands the high-voltage range. Additionally, the process of processing the sampled data using the data processing unit further includes: setting a first preset time period; after the first preset time period has elapsed, performing calculations using effective beam current parameter estimates; outputting voltage control signals to control the low-voltage output. Performing calculations after the preset time period, when the beam current signal is stable, improves the accuracy of the low-voltage output.

[0044] The high-frequency composite pulse electron beam welding beam current feedback control system of this application includes: the high-frequency composite pulse electron beam welding beam current feedback control circuit and the electron beam generating device described in this application. The electron beam generating device is connected to a power supply unit and a sampling unit, and is used to generate an electron beam acting on the workpiece according to the output voltage of the power supply unit. The sampling unit is used to collect the current signal of the electron beam current and the voltage signal of the power supply unit, and amplifies the current signal and the voltage signal respectively to obtain a sampled current signal and a sampled voltage signal. The data processing unit performs calculations based on the sampled current signal and the sampled voltage signal of the power supply unit, and outputs a voltage control signal, which is used to adjust the output voltage of the power supply unit. The power supply unit is used to adjust the low-voltage output of the power supply unit according to the voltage control signal output by the data processing unit. The power supply unit inverts and converts the low-voltage output to output a high voltage. The high voltage output of the power supply unit is transmitted to the electron beam generating device, and the electron beam generating device controls the electron beam current according to the high voltage. By placing the sampling resistor inside the vacuum chamber and grounding the chamber shell to effectively shield it from external interference, the accuracy of the sampling signal is ensured. Through a series of calculations on the sampled data, precise control of the beam is achieved. Attached Figure Description

[0045] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0046] Figure 1 This is a schematic diagram of a control circuit structure according to an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the structure of the sampling circuit to the second amplifier circuit according to an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the structure of the third amplifier circuit to analog-to-digital converter circuit provided according to an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of the control system structure provided according to an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of the control method structure provided according to an embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram of beam parameter waveforms provided according to an embodiment of the present invention;

[0052] Figure 7This is a schematic diagram of histogram data distribution according to an embodiment of the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of the present invention to enable the reader to better understand the present invention. However, the technical solutions claimed in the present invention can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0054] Example 1:

[0055] The embodiments of the present invention relate to a high-frequency composite pulse electron beam welding beam current feedback control circuit.

[0056] Compared with the prior art, the embodiments of the present invention employ a sampling unit, a data processing unit, and a power supply unit to sample the current parameters of the beam, convert them into voltage for amplification, and then convert the amplified result back into current and transmit it to the data processing unit. The data processing unit performs calculations to obtain effective estimated values ​​of the beam parameters and controls the output of the power supply unit, thus solving the problem of feedback control of the beam.

[0057] The following is a detailed description of the implementation details of the beam feedback control circuit in this embodiment. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0058] This invention provides a high-frequency composite pulsed electron beam welding beam current feedback control circuit, comprising: a sampling unit, a data processing unit, and a power supply unit. The data processing unit is connected to both the sampling unit and the power supply unit. The sampling unit is used to acquire the current signal of the electron beam and the voltage signal of the power supply unit, and amplifies the current signal and voltage signal respectively to obtain a sampled current signal and a sampled voltage signal. The data processing unit performs calculations based on the sampled current signal and sampled voltage signal, and outputs a voltage control signal, which is used to adjust the output voltage of the power supply unit. The power supply unit is used to adjust the low-voltage output of the power supply unit according to the voltage control signal output by the data processing unit. The power supply unit inverts and converts the low-voltage output to output a high voltage, which is used to control the electron beam.

[0059] The sampling unit acquires the current signal of the electron beam, performs voltage division and amplification on the acquired current signal to obtain a sampled current signal, which is a digital voltage signal. It also acquires the voltage signal from the power supply unit to obtain a sampled voltage signal, which is also a digital voltage signal. Both the sampled current and voltage signals are transmitted to the data processing unit. The data processing unit performs calculations based on the acquired sampled current and voltage signals and outputs a voltage control signal to adjust the voltage of the power supply unit. The power supply unit, based on the voltage control signal, outputs the adjusted voltage to control the electron beam, thus achieving feedback control of the welding beam. Figure 1 As shown.

[0060] The sampling unit includes a current sampling module and a voltage sampling module. The current sampling module is used to acquire the current signal of the electron beam, and the voltage sampling module is used to acquire the voltage signal of the power supply unit.

[0061] The current sampling module includes a sampling circuit, an amplification circuit, and a voltage-to-current conversion circuit connected in sequence. The sampling circuit is used to acquire the current signal of the electron beam to obtain the acquired voltage signal. The amplification circuit is used to amplify the acquired voltage signal to obtain the amplified voltage signal. The voltage-to-current conversion circuit is used to convert the amplified voltage signal into a sampled current signal and transmit it to the data processing unit.

[0062] The data processing unit includes a current-to-voltage conversion circuit, an analog-to-digital conversion circuit, and a control circuit connected in sequence. The current-to-voltage conversion circuit converts the current signal of the sampling unit into a voltage signal and samples it to obtain an analog voltage signal. The analog-to-digital conversion circuit performs analog-to-digital conversion on the analog voltage signal to obtain a digital sampled current signal. The control circuit performs calculations based on the digital sampled current signal and the sampled voltage signal of the power supply unit to obtain a voltage control signal, which is then transmitted to the power supply unit.

[0063] The power supply unit controls the output voltage according to the voltage control signal, thereby controlling the electron beam current and realizing feedback control of the welding beam current.

[0064] The sampling circuit is used to acquire the beam current magnitude. It includes a sampling sub-circuit and a voltage divider sub-circuit connected in parallel. The sampling sub-circuit is used to acquire the beam current magnitude acting on the workpiece and prevent transient high voltage. The voltage divider sub-circuit is used to divide and filter the sampled signal to obtain the acquired voltage signal.

[0065] The sampling sub-circuit includes a sampling resistor and a transient suppression diode connected in parallel. The sampling resistor is used to collect the beam current acting on the workpiece, and the transient suppression diode is used to suppress the instantaneous voltage increase caused by the instantaneous current.

[0066] The sampling resistor is a non-inductive resistor to avoid waveform distortion of the high-frequency pulse beam signal under test. The transient suppression diode is used to protect the subsequent circuits and prevent damage from overvoltage.

[0067] The voltage divider circuit includes a combination of resistors and capacitors for filtering and dividing the sampled signal, effectively suppressing common-mode noise.

[0068] The amplifier circuit is used to amplify the acquired voltage signal in multiple stages to obtain an amplified voltage signal.

[0069] It includes a first amplification sub-circuit, a voltage follower sub-circuit, a second amplification sub-circuit, and a third amplification sub-circuit connected in sequence.

[0070] The first amplification sub-circuit includes a high-speed instrumentation amplifier for precise amplification of the acquired voltage signal. This ensures accurate measurement of the pulse beam signal while effectively suppressing common-mode noise.

[0071] The voltage follower sub-circuit is used to follow the first amplification result of the first amplification sub-circuit.

[0072] The second amplifier sub-circuit includes a high-speed isolation amplifier, which is used for impedance isolation and amplification, electrically isolating the preceding and following stage circuits and protecting the following stage circuit.

[0073] The third amplifier sub-circuit includes a differential amplifier, which is used to amplify the signal again to obtain an amplified voltage signal.

[0074] Voltage-to-current conversion circuits are used to convert amplified voltage signals into current signals. These circuits include current transmitters that convert voltage signals into current signals for long-distance transmission, reducing losses.

[0075] The current-to-voltage conversion circuit includes a conversion resistor to convert current into voltage for long-distance transmission, reducing losses.

[0076] The analog-to-digital converter circuit converts the analog voltage across the switching resistor into a digital value, thus obtaining the sampled current signal.

[0077] The control circuit receives the sampling current signal output by the sampling unit and the sampling voltage signal output by the power supply unit, performs calculations to obtain a voltage control signal, controls the output voltage of the power supply unit, and thus controls the electron beam current to achieve feedback control.

[0078] The power supply unit includes a low-frequency bias module, an inverter module, an isolation transformer module, and a high-frequency bias module. The low-frequency bias module includes a first low-frequency pulse bias power supply circuit and a second low-frequency pulse bias power supply circuit. The inverter module includes a first inverter circuit and a second inverter circuit. The isolation transformer module includes a first isolation transformer and a second isolation transformer. The high-frequency bias module includes a first high-frequency pulse bias power supply high-voltage circuit and a second high-frequency pulse bias power supply high-voltage circuit.

[0079] The first low-frequency pulse bias power supply circuit, the first inverter circuit, the first isolation transformer, and the first high-frequency pulse bias power supply high-voltage circuit are connected in sequence to form the first high-voltage generating circuit. The second low-frequency pulse bias power supply circuit, the second inverter circuit, the second isolation transformer, and the second high-frequency pulse bias power supply high-voltage circuit are connected in sequence to form the second high-voltage generating circuit. The output of the first high-voltage generating circuit and the output of the second high-voltage generating circuit are connected in series to control the generation voltage of the electron beam.

[0080] The first low-frequency pulse bias power supply circuit is used to output a first low voltage. Its output is connected to the input terminal of the first inverter circuit. The first inverter circuit is used to invert the first low voltage to obtain a first AC voltage. The first isolation transformer induces the first AC voltage to the first high-frequency pulse bias power supply high-voltage circuit to generate a first high voltage.

[0081] Similarly, the second low-frequency pulse bias power supply circuit is used to output a second low voltage. Its output is connected to the input terminal of the second inverter circuit. The second inverter circuit is used to invert the second low voltage to obtain a second AC voltage. The second isolation transformer induces the second AC voltage to the second high-frequency pulse bias power supply high-voltage circuit to generate a second high voltage.

[0082] The first high voltage and the second high voltage are connected in series to output the control voltage of the electron beam.

[0083] The voltage sampling module of the sampling unit collects the voltage signals of the first low voltage and the second low voltage respectively. The control circuit performs analog-to-digital conversion on the first low voltage acquisition signal and the second low voltage acquisition signal respectively to obtain the sampled voltage signal, which includes the first low voltage sampled voltage signal and the second low voltage sampled voltage signal.

[0084] The voltage control signals output by the control module are used to control the first low-frequency pulse bias power supply circuit, the second low-frequency pulse bias power supply circuit, and the second inverter circuit, respectively, to control the first voltage output, the second voltage output, and the second AC voltage output, thereby realizing the output control of the first high voltage and the second high voltage.

[0085] Example 2

[0086] The embodiments of the present invention are a detailed description of the above-described Example 1.

[0087] like Figure 2 As shown, the sampling sub-circuit includes a sampling resistor R9 and a transient suppression diode (TVS) D1. The sampling resistor R9 and the TVS diode D1 are connected in parallel. One end is used to connect to the beam output terminal acting on the workpiece, and the other end is connected to ground. The current flowing through the resistor R9 is collected to obtain the sampling voltage.

[0088] The voltage divider circuit includes a series combination of capacitors C4 and C12 and a series combination of resistors R5 and R16. These capacitor and resistor combinations are connected in parallel with the sampling sub-circuit. The connection points of the capacitor and resistor combinations are connected to ground GND1. Capacitor C4 and resistor R5 are connected in parallel, as are capacitor C12 and resistor R16. Capacitors C4 and C12 are used for voltage division and filtering of the sampled voltage, while resistors R5 and R16 are used for voltage division of the sampled voltage. Using a RC voltage divider effectively suppresses common-mode noise.

[0089] The first amplification sub-circuit includes operational amplifiers U1, U3, and U5, and their peripheral circuits. The positive input terminal of operational amplifier U1 is connected to the beam output terminal through resistor R1, and the negative input terminal is connected to one end of resistor R7 and one end of resistor R11. Its output terminal is connected to the other end of resistor R7 and one end of resistor R8. The positive input terminal of operational amplifier U5 is connected to ground through resistor R20, and its negative input terminal is connected to the other end of resistor R11 and one end of resistor R13. Its output terminal is connected to the other end of resistor R13 and one end of resistor R14. The positive input terminal of operational amplifier U3 is connected to the other end of resistor R14 and one end of resistor R17, and its negative input terminal is connected to the other end of resistor R18, one end of resistor R3, and one end of capacitor C2. Its output terminal is connected to the other end of resistor R3 and the other end of capacitor C2, and serves as the output terminal of the first amplification sub-circuit. The other end of resistor R17 is grounded to GND1.

[0090] Operational amplifiers U1, U3, and U5 are connected to positive and negative 5V power supplies respectively, and the power supplies are filtered.

[0091] The voltage follower sub-circuit includes operational amplifier U4 and its peripheral circuits. The positive input terminal of operational amplifier U4 is connected to one end of resistor R10 and one end of resistor R6. The other end of resistor R10 is connected to the output terminal of the first amplification sub-circuit. Its negative input terminal is connected to one end of resistor R19, and its output terminal is connected to the other end of resistor R19, serving as the output terminal of the voltage follower sub-circuit. The other end of resistor R6 is connected to one end of resistor R2 and one end of resistor R4. The other end of resistor R2 is connected to the first 5V power supply terminal, and the other end of resistor R4 is grounded to GND1.

[0092] The series combination of resistors R2 and R4 divides the 5V voltage. The voltage division result is applied to the positive input terminal of operational amplifier U4 through resistor R6, which is equivalent to setting a bias voltage for the positive input terminal of operational amplifier U4. The output of the first amplification sub-circuit is also applied to the positive input terminal of operational amplifier U4 through resistor R10, and operational amplifier U4 follows the output of the first amplification sub-circuit.

[0093] The second amplifier sub-circuit includes a high-speed isolation amplifier U2 and its peripheral circuits. The AIP terminal of the high-speed isolation amplifier U2 is connected to one end of resistor R12 and one end of capacitor C10. Its AIN terminal is connected to one end of resistor R15 and the other end of capacitor C10. The other end of resistor R15 is connected to one end of resistor R18 and one end of resistor R21. The other end of resistor R21 is connected to the 3.3V power supply terminal. The other end of resistor R18 is grounded to GND1. Capacitor C15 is connected in parallel between the 3.3V power supply and ground GND1 for filtering the 3.3V power supply.

[0094] The series combination of resistors R21 and R18 divides the 3.3V voltage. The voltage division result is applied to the AIN input terminal of the high-speed isolation amplifier U2 through resistor R15, which is equivalent to setting a bias voltage for the AIN input terminal of the high-speed isolation amplifier U2.

[0095] The high-speed isolation amplifier U2 uses a 3.3V power supply, and its AOP and AON terminals serve as the output terminals of the second amplification sub-circuit.

[0096] like Figure 3 As shown, the third amplification sub-circuit includes a differential amplifier U7 and its peripheral circuits. The positive input terminal of the differential amplifier U7 is connected to one end of resistor R28 and one end of resistor R29. The other end of resistor R28 is connected to the AOP output terminal of the second amplification sub-circuit and one end of capacitor C21. The negative input terminal of the differential amplifier U7 is connected to one end of resistor R26, one end of resistor R23, and one end of capacitor C17. The other end of resistor R26 is connected to the AON output terminal of the second amplification sub-circuit and the other end of capacitor C21. Capacitor C21 is used to filter the signal between the AOP terminal and the AON terminal. The other end of resistor R29 is grounded to GND2. The output terminal of the differential amplifier U7 is connected to the other end of resistor R23 and the other end of capacitor C17, and serves as the output terminal of the third amplification sub-circuit.

[0097] The series combination of resistors R28 and R29 is used to divide the output signal at the AOP terminal.

[0098] The voltage-to-current conversion circuit includes a current transmitter, which includes an operational amplifier U6 and its peripheral circuitry. The positive input terminal of the operational amplifier U6 is connected to one end of resistor R27, one end of resistor R32, and one end of resistor R25. Its negative input terminal is grounded to GND2. The other end of one end of resistor R27 is connected to the output terminal of the third amplifier sub-circuit. The other end of resistor R25 is connected to one end of resistor R22 and one end of resistor R24. One end of resistor R22 is connected to the second 5V power supply terminal, and the other end of resistor R24 ​​is grounded to GND2. The other end of resistor R32 is connected to one end of resistor R33 and serves as the second output terminal of the voltage-to-current conversion circuit. The other end of resistor R33 is connected to one end of resistor R30 and grounded to GND2.

[0099] The output of operational amplifier U6 is connected to the base of NPN transistor Q1. The emitter of transistor Q1 is grounded to GND2 through resistor R30. The collector of transistor Q1 is connected to the positive terminal of power supply E and serves as the first output of the voltage-to-current conversion circuit.

[0100] Operational amplifier U6 and transistor Q1 convert the input voltage into current. Taking advantage of the small error, strong anti-interference ability, and suitability for long-distance transmission of current signals, the transmission distance is increased.

[0101] The current-to-voltage conversion circuit includes a power supply E and a conversion resistor R31. The positive output terminal of the power supply E serves as one input terminal of the current-to-voltage conversion circuit and is connected to the first output terminal of the voltage-to-current conversion circuit. One end of the conversion resistor R31 is connected to the negative terminal of the power supply E, and the other end serves as another input terminal of the current-to-voltage conversion circuit and is connected to the second output terminal of the voltage-to-current conversion circuit.

[0102] In one embodiment of this application, the conversion power supply E is connected in series with the conversion resistor R31. One end of the conversion resistor R31 is connected to the positive terminal of the conversion power supply E, and the other end serves as an input terminal of the current-to-voltage conversion circuit, connected to the first output terminal of the voltage-to-current conversion circuit. The negative terminal of the conversion power supply E serves as another input terminal of the current-to-voltage conversion circuit, connected to the second output terminal of the voltage-to-current conversion circuit.

[0103] The analog-to-digital converter (ADC) circuit samples the voltage across the conversion resistor, performs analog-to-digital conversion, and obtains the sampled current signal.

[0104] Example 3:

[0105] This invention provides a high-frequency composite pulse electron beam welding beam current feedback control system, including a high-frequency composite pulse electron beam welding beam current feedback control circuit and an electron beam generating device. The electron beam generating device is connected to a power supply unit and a sampling unit, and is used to generate an electron beam acting on the workpiece according to the output voltage of the power supply unit. The sampling unit is used to collect the current signal of the electron beam and the voltage signal of the power supply unit, and amplifies the current signal and voltage signal respectively to obtain a sampled current signal and a sampled voltage signal. The data processing unit performs calculations based on the sampled current signal and the sampled signal of the power supply unit, and outputs a voltage control signal, which controls the output voltage of the power supply unit. The power supply unit is used to adjust the low-voltage output of the power supply unit according to the voltage control signal output by the data processing unit. The power supply unit inverts and converts the low-voltage output to output a high voltage, which is transmitted to the electron beam generating device, and the electron beam generating device uses the high voltage to control the electron beam current.

[0106] like Figure 1 As shown, a high-frequency composite pulse electron beam welding beam current feedback control system includes a sampling unit, a data processing unit, a power supply unit, and an electron beam generating device. The electron beam generating device is connected to the power supply unit and the sampling unit, and is used to generate an electron beam based on the output voltage of the power supply unit, which then acts on the workpiece. The sampling unit is used to collect the current signal of the electron beam and the voltage signal of the power supply unit, converting the electron beam current signal into a voltage for acquisition, and then performing voltage division and amplification on the acquired voltage signal. The amplified voltage signal is then converted back into a current to obtain the sampled current signal. Taking advantage of the small error and strong anti-interference capability of the current signal during transmission, long-distance transmission is achieved.

[0107] The power supply unit includes a first high-voltage generating circuit and a second high-voltage generating circuit. The output of the first high-voltage generating circuit is connected in series with the output of the second high-voltage generating circuit to obtain the generation voltage of the electron beam.

[0108] The sampling unit also acquires the first low voltage and the second low voltage of the power supply unit to obtain the first low voltage sampling voltage signal and the second low voltage sampling voltage signal.

[0109] After receiving the sampling current signal, the first low-voltage sampling voltage signal, and the second low-voltage sampling voltage signal, the data processing unit performs calculations and outputs a voltage control signal to control the output voltage of the power supply unit, thereby realizing feedback control of the electron beam current.

[0110] Example 4

[0111] The embodiments of the present invention are a detailed description of the above-described Example 3.

[0112] like Figure 4As shown, the power supply unit includes: a first high voltage generating circuit and a second high voltage generating circuit. The first high voltage generating circuit is used to convert a first low voltage into a first high voltage, and the second high voltage generating circuit is used to convert a second low voltage into a second high voltage. The first high voltage and the second high voltage are connected in series and superimposed to output a third high voltage, which is used to provide bias voltage to the electron beam generating device.

[0113] The first high-voltage generating circuit includes a first low-frequency pulse bias power supply circuit, a first inverter circuit, a first isolation transformer, and a first high-frequency pulse bias power supply high-voltage circuit connected in sequence. The first low-frequency pulse bias power supply circuit is used to output a first low voltage U1. The first inverter circuit converts the first low voltage U1 into a first AC current. The first isolation transformer isolates and transforms the first AC current to obtain a second AC current. The first high-frequency pulse bias power supply high-voltage circuit generates a first high voltage U3 based on the second AC current. The first low voltage U1 and the first high voltage U3 are direct current.

[0114] The second high-voltage generating circuit includes a second low-frequency pulse bias power supply circuit, a second inverter circuit, a second isolation transformer, and a second high-frequency pulse bias power supply high-voltage circuit connected in sequence. The second low-frequency pulse bias power supply circuit outputs a second low voltage U2. The second inverter circuit converts the second low voltage U2 into a third AC current. The second isolation transformer isolates and transforms the third AC current to obtain a fourth AC current. The second high-frequency pulse bias power supply high-voltage circuit generates a second high voltage U based on the fourth AC current. The second low voltage U2 and the second high voltage U4 are direct current.

[0115] The negative output terminal of the first high voltage U3 is connected to the positive output terminal of the second high voltage U4. The positive output terminal of the first high voltage U3 serves as the positive output terminal of the power supply unit, and the negative output terminal of the second high voltage U4 serves as the negative output terminal of the power supply unit, outputting the third high voltage U5.

[0116] The sampling unit samples the first low voltage U1 and the second low voltage U2, and performs calculations on them respectively to obtain the first low voltage sampled voltage signal and the second low voltage sampled voltage signal. The calculations include at least one of signal filtering, amplification, and analog-to-digital conversion.

[0117] The electron beam generating device includes a high-voltage accelerating power supply, a filament heating power supply, and an electron beam generator. The negative output terminal of the high-voltage accelerating power supply is connected to the positive output terminal of the third high-voltage U5, and its positive output terminal is grounded. The positive output terminal of the third high-voltage U5 is connected to the series connection point of series resistors R1 / R2. The series combination of series resistors R1 / R2 is connected in parallel between the positive and negative output terminals of the filament heating power supply. The positive output terminal of the filament heating power supply is connected to the insulating block 2 of the electron beam generator, and the negative output terminal is connected to the insulating block 1 of the electron beam generator. The electron beam generator includes a filament 3, an insulating block 4, a bias grid 5, a high-voltage anode 6, a coaxial coil 7, an astigmatism correction coil 8, a vacuum chamber wall 9, a focusing coil 10, a deflection coil 11, an electron beam 12, an insulating block 13, a beam sampling circuit 14, a workpiece 15, a pad 16, an insulating plate 17, and a motion platform 18. The filament heating power supply applies pressure to both ends of the filament 3 to generate an electron beam. The bias grid 5, high voltage anode 6, coaxial coil 7, astigmatism-eliminating coil 8, focusing coil 10, and deflection coil 11 accelerate the electron beam, causing the electron beam current 12 to act on the workpiece 15. The conduction current and penetration current flow through the pad 16 and through the beam sampling circuit 14. The beam sampling circuit 14 returns to the positive terminal of the high voltage accelerating power supply through the moving platform 18 connected to the ground.

[0118] The beam sampling circuit 14 is set inside the vacuum chamber. The vacuum chamber shell, which is connected to the ground, can effectively shield external interference. The signal input terminals of the sampling circuit are connected to the pad under the workpiece and the grounded motion platform, respectively. The pad and the motion platform are electrically isolated by an insulating plate, which ensures that the sampling signal has low noise and no distortion.

[0119] Example 5

[0120] The embodiments of the present invention provide a high-frequency composite pulse electron beam welding beam current feedback control method, including using a sampling unit to collect the current signal of the electron beam current and the low voltage signal of the power supply unit, and amplifying the sampling current signal and the sampling voltage signal respectively to obtain sampling data, wherein the sampling data includes the sampling current signal of the electron beam current and the sampling voltage signal of the power supply unit;

[0121] Using a data processing unit, pulsed electron beam parameters are set, and a voltage control signal is output according to the beam-bias voltage lookup table to control the low-voltage output of the power supply unit; and the data processing unit performs calculations on the sampled data to adjust the voltage control signal, and then adjusts the low-voltage output of the power supply unit based on the adjusted voltage control signal.

[0122] The power supply unit is controlled by the voltage control signal to adjust the low-voltage output and then inverts and converts the low-voltage output to output a high-voltage output; and

[0123] The high-voltage output of the power supply unit controls the electron beam.

[0124] Low pressure includes the first low pressure and the second low pressure.

[0125] The pulsed electron beam parameters are set, and the first and second low-voltage parameters are adjusted according to the beam-bias voltage lookup table to quickly adjust the electron beam to near the set value and maintain a stable state. The first and second low-voltages are sampled, and the sampled current signal of the electron beam is sampled for data shaping. Within each calculation cycle, the integral value SH and distribution of the sampled data within the high-frequency pulsed beam cycle are used, combined with the maximum and minimum values ​​of SH within the calculation cycle (i.e., the extreme value method), to solve for the base peak parameter value in the high-frequency composite pulsed beam waveform. This allows for fine-tuning of the electron beam, improving the accuracy of the output beam waveform. During fine-tuning, the bias data in the "beam-bias voltage lookup table" is updated to improve the accuracy of the coarse-tuning results.

[0126] In one specific embodiment of this application, the calculation period is the period of the low-frequency pulse beam.

[0127] like Figure 5 As shown in a specific embodiment of this application, the high-frequency composite pulsed electron beam welding beam current feedback control method includes:

[0128] Set the pulsed electron beam parameters 49. According to the beam-bias voltage lookup table and the set parameters 50, control the output of the first low voltage and the second low voltage 51. Sample the first low voltage, the second low voltage 54 and the electron beam value 55. Based on the sampled values ​​of the first low voltage and the second low voltage, perform the first PID calculation 52 and output a voltage control signal 53 to adjust the output of the first low voltage and the second low voltage, i.e., the first low voltage output adjustment, which is the inner loop of the beam feedback, also known as beam coarse adjustment. Perform data shaping on the sampled values ​​of the electron beam value 56 and 57 to obtain sampled data. Calculate the sampled data, including block diagrams 58 to 64, to obtain an effective current estimate. Perform the second calculation 65 based on the effective current estimate and output a voltage control signal to adjust the output of the first low voltage and the second low voltage, i.e., the second low voltage output adjustment, also known as beam fine adjustment. When the effective current estimate meets the conditions 66, update the beam-bias voltage lookup table 67.

[0129] Specifically, the pulsed electron beam parameters include low-frequency pulsed beam parameters and high-frequency pulsed beam parameters. The low-frequency pulsed beam parameters include the base current. I b Peak current I p low frequency f L Low-frequency duty cycle d L The high-frequency pulsed beam parameters include the base stack peak current. I bp Peak-to-peak currentI pp High frequency f H High-frequency duty cycle d H A high-frequency signal superimposed on a low-frequency signal results in a base current. I b , base stack peak current I bp Peak current I p Peak-to-peak current I pp The relationship between them, such as Figure 6 As shown, the peak current of the base stack I bp It is the base current at low frequency. I b Superimposed high-frequency peak current, peak-to-peak current I pp It is a high-frequency peak current superimposed on a low-frequency peak current, where the first low voltage U1 is... U p High level, second low voltage U2 is U pp When the level is low, the corresponding reference current is... I b Low, at the reference current I b The peak current of the superimposed base is I bp ; in the first low voltage U1 is U b Low level, the second low voltage U2 is U bp When the level is high, the corresponding peak current is I p High, at peak current I p Superimposed peak peak current I pp .

[0130] The sampled current signal is shaped, including linear verification and digital filtering, to obtain the sampled data.

[0131] The sampled data is processed, including:

[0132] With a low-frequency pulsed beam period of 1 / f LFor each high-frequency pulse sampled data within the parameter operation period, the first integral value is calculated. If the rate of change between the first integral value of the current high-frequency pulse and the first integral value of the previous high-frequency pulse is less than a threshold, the first integral value of the current high-frequency pulse is considered a valid integral value. This yields a dataset of valid integral values ​​within one parameter operation period, thus obtaining the maximum and minimum valid integral values. Based on the maximum valid integral value, its corresponding distribution histogram, and the high-frequency pulse parameters, the estimated peak current value is calculated. I p Peak-to-peak current estimation value I pp Based on the minimum effective integral, the histogram of the distribution corresponding to the minimum effective integral, and the high-frequency pulse parameters, the estimated value of the reference current is calculated. I b Estimated peak current of the base stack I bp Based on the current estimate, the third integral value of the current estimate is calculated, the second integral value of the sampled data is calculated, and the first deviation rate between the third integral value and the second integral value is calculated. When the first deviation rate is less than the first deviation rate threshold, the current estimate is valid. Based on the valid current estimate, after a period of time longer than the first set time, a second PID operation is performed, and a voltage control signal is output to control the output of the first low voltage and the second low voltage, and to control the output of the third high voltage. Within the second set time, the second deviation rate between the current estimate and the set value is calculated. When the current estimate is less than the second deviation rate threshold, the beam current-bias voltage lookup table is updated.

[0133] Calculate the effective integral value and the current estimate, including:

[0134] A1. Calculate the period 1 / f of a low-frequency pulsed beam. L 1 / f of each high-frequency cycle within H The first integral value S of the sampled data H To obtain a low-frequency pulsed beam period 1 / f L From the dataset of valid integral values, obtain the maximum and minimum valid integral values, f. L f represents the low-frequency pulsed beam frequency. H Indicates the frequency of a high-frequency pulse;

[0135] A2. Statistical analysis of low-frequency pulse beam period 1 / f L 1 / f of each high-frequency cycle within H The distribution of the sampled data is used to approximate the estimated beam parameters by taking the boundary or median values ​​of the region with the highest number of sampled data. I 1 or I 1p ;

[0136] A3. Based on the maximum effective integral value in A1 and the corresponding beam parameter calculation values ​​in A2, combined with the set beam parameters, obtain the first estimated beam parameter values, including the estimated peak current value. I p Peak-to-peak current estimation value I pp Based on the minimum effective integral value in A1 and the corresponding calculated beam parameter value in A2, combined with the set beam parameters, the estimated values ​​of the second beam parameters are obtained, including the estimated base current value. I b Estimated peak current of the base stack I bp ;

[0137] A4. Based on the sampled data, calculate a low-frequency pulse beam period 1 / f. L The second integral value S of the internally sampled data L ;

[0138] A5. Calculate the low-frequency pulsed beam period 1 / f L The third integral value S of the beam parameter estimation. C Calculate the third integral value S C With the second integral value S in A4 L If the first deviation rate is greater than or equal to the first deviation rate threshold, the estimated beam parameter value is incorrectly calculated, and the process returns to A1 to start over; if the first deviation rate is less than the first deviation rate threshold, the estimated beam parameter value is valid, and the process proceeds to the next step.

[0139] A6. After the first set time period, the second PID calculation is performed based on the estimated beam parameters, and the voltage control signal is output to adjust the output of the first low voltage and the second low voltage.

[0140] A7. Calculate the second deviation rate between the estimated beam parameter value calculated in A3 and the set value within the second set time period. If the second deviation rate is less than the second deviation rate threshold, update the beam-bias comparison table.

[0141] Specifically, A1 includes:

[0142] Calculate the period 1 / f of a low-frequency pulsed beam. L 1 / f of each high-frequency cycle within H The first integral value S of the sampled data H Calculate the current first integral value S Hi The first integral value S of the previous high-frequency cycle H(i-1) rate of change s H and the rate of change sH With the rate of change threshold s H,th Comparison, if the rate of change s H Less than the rate of change threshold s H,th Then mark the current first integral value S. Hi For the effective integral value S H The effective integral value indicates that the current beam is in a stable phase, and the beam waveform in the stable phase is more in line with a square wave.

[0143] Calculate the period 1 / f of a low-frequency pulsed beam. L The effective integral value S of all high-frequency pulses within H A low-frequency pulsed beam period of 1 / f is obtained. L From the dataset of valid integral values, obtain the minimum valid integral value S. H，MIN and the maximum effective integral S H，MAX .

[0144] A2 includes:

[0145] Histograms were used to statistically analyze the low-frequency pulse beam period 1 / f. L 1 / f of each high-frequency cycle within H The distribution of the sampled data includes:

[0146] The beam spacing value i (mA) of the distribution histogram is used as the accuracy value for solving the beam parameters. Since the pulsed beam waveform is a square wave, the beam current... I x ( I b or I p )or I xp ( I bp or I pp A beam current value in ) I 1. It must be located in the interval with the largest number of sampled values ​​in the distribution histogram, and the median value of the interval with the largest number of samples is used as an approximation. I x ( I b or I p )or I xp ( I bp or I pp At this point, a beam current value is obtained. I 1 is Ix or I xp one of the.

[0147] Histogram structure, such as Figure 7 As shown, different amounts of data are distributed in different intervals. The interval with the most data is selected, and a value from that interval is taken as the beam value. I 1.

[0148] A3 includes:

[0149] Based on the maximum effective integral S H，MAX With the maximum effective integral S H，MAX The corresponding distribution histogram is used to solve for the beam value. I 1. Combining high-frequency pulse parameters, including duty cycle. d H and frequency f H Then, the first set of estimated beam parameters, including the estimated peak current, is calculated. I p Peak-to-peak current estimation value I pp ;

[0150] At this point, assuming the beam current value... I 1 is I p ,but I pp = ( S H，MAX f H - I 1(1 - d H )) / d H The final decision is made based on the magnitude of the two values. I p or I pp ;

[0151] like( S H，MAX f H - I 1(1 - d H )) / d H Greater than or equal to I 1. Then the assumption is true:

[0152] I p = I 1.I pp = ( S H，MAX f H - I 1(1 - d H )) / d H .

[0153] like( S H，MAX f H - I 1(1 - d H )) / d H Less than I 1. Then the assumption is not true:

[0154] I pp = I 1. I p = ( S H，MAX f H - I 1 d H ) / (1 - d H ).

[0155] Similarly, solve I b and I bp :

[0156] Based on the minimum effective integral S H，MIN minimum effective integral S H，MIN The corresponding distribution histogram was used to solve for the value. I 1. Combining the high-frequency pulse rectification cycle parameters, the high-frequency pulse parameters include the duty cycle. d H and frequency f H Then, the second set of estimated beam parameters is calculated, including the estimated reference current. I b Estimated peak current of the base stack I bp ;

[0157] At this point, the assumed value I 1 is I b ,but Ibp = ( S H，MIN f H - I 1(1 - d H )) / d H The final decision is made based on the magnitude of the two values. I b or I pp ;

[0158] like( S H，MIN f H - I 1(1 - d H )) / d H Greater than or equal to I 1. Then the assumption is true:

[0159] I b = I 1. I bp = ( S H，MIN f H - I 1(1 - d H )) / d H .

[0160] like( S H，MIN f H - I 1(1 - d H )) / d H Less than I 1. Then the assumption is not true:

[0161] I bp = I 1. I b = ( S H，MIN f H - I 1 d H ) / (1 - dH ).

[0162] After the above calculations, a low-frequency pulse beam period 1 / f is obtained. L The estimated beam current parameters, including the estimated reference current, are included. I b Estimated peak current of the base stack I bp Peak current estimation value I p Peak-to-peak current estimation value I pp .

[0163] A5 includes:

[0164] Based on the estimated beam parameters, calculate the third integral S of the estimated beam parameters. C Calculate the third integral value S C With the second integral value S L The first deviation rate between e L Determine the first deviation rate e L Is it less than the first deviation rate threshold? e L,th , if the first deviation rate e L Less than the first deviation rate threshold e L,th This indicates that the beam waveform is in a stable state, and the calculated... I b , I p , I bp , I pp Valid; if the first deviation rate e L Greater than or equal to the first deviation rate threshold e L,th This indicates that the estimated value is incorrect; recalculate starting from A1.

[0165] Set the pulse beam parameters at t=0. t >t1, that is, after the first set time period, a second PID calculation is performed based on the effective estimated value of the beam parameters, and the output voltage control signal is used to control the output of the first low voltage, the second low voltage and the third high voltage, and to adjust the base peak parameter value in the high frequency composite pulse beam waveform. This is the outer loop of beam feedback, also known as beam fine adjustment.

[0166] During the fine-tuning process, within the second set time period, the second deviation rate between the effective current estimate and the set value is calculated. When the second deviation rate is less than the second deviation rate threshold, the beam current-bias voltage comparison table is updated to make the next coarse-tuning result more accurate.

[0167] The high-frequency composite pulse electron beam welding beam feedback control method in this embodiment performs integral calculations on the high-frequency pulse sampling data, ignoring the influence of timing, delay, and other factors on the beam parameters. Based on the result of the integral calculation, the maximum and minimum values ​​of the integral calculation result are selected. A value is obtained from the interval with the most data in the statistical data distribution histogram corresponding to the maximum value of the integral calculation result, approximating a beam parameter estimate. Combined with the high-frequency pulse parameters, a first set of beam parameter estimates is calculated. Similarly, a value is obtained from the interval with the most data in the statistical data distribution histogram corresponding to the minimum value of the integral calculation result, approximating a beam parameter estimate. Combined with the high-frequency pulse parameters... The second set of estimated beam parameters is calculated, thereby calculating the estimated values ​​of all beam currents in one operation cycle. The estimated beam currents are then integrated to obtain the third integral, and the sampled data is integrated to obtain the second integral. The deviation rate between the third integral and the second integral is calculated. If the deviation rate is less than the deviation rate threshold, the estimated value is considered valid. Through the above calculations, the influence of real-time sampled data on feedback due to factors such as delay and interference is eliminated, ensuring the accuracy of the data used for feedback calculation and the accuracy of feedback adjustment of the first and second low voltages. The beam-bias comparison table is updated with the valid estimated values, further improving the accuracy of bias control.

[0168] This application designs a method for calculating the waveform parameters of a high-frequency composite pulse beam based on the integral values ​​of sampled data within high- and low-frequency pulse periods and the distribution of sampled data within high-frequency pulse periods. When the pulse beam output is relatively stable, this method can effectively solve for the base peak parameter values ​​in both conventional pulse beam waveforms and high-frequency composite pulse beam waveforms, which are then used for feedback control, improving the accuracy of the feedback control. It also solves the problem of large deviations between the actual output beam parameters and the setpoint values ​​during high-frequency pulses.

[0169] It should be understood that the terms "mechanism," "device," "component," etc., used in this application are merely one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they can be replaced by other expressions.

[0170] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention. In practical applications, the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification, and various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A high-frequency composite pulse electron beam welding beam current feedback control circuit, characterized in that, include: The system comprises a sampling unit, a data processing unit, and a power supply unit, with the data processing unit connected to both the sampling unit and the power supply unit. The sampling unit acquires the current signal of the electron beam and the voltage signal of the power supply unit, amplifies the current signal and voltage signal respectively, and obtains the sampled current signal and sampled voltage signal. The data processing unit performs calculations based on the sampled current signal and sampled voltage signal, and outputs a voltage control signal, which is used to adjust the output voltage of the power supply unit. The power supply unit adjusts its low-voltage output based on the voltage control signal output by the data processing unit. The power supply unit inverts and converts the low-voltage output to output a high-voltage output, which is used to control the electron beam. The sampling unit includes a current sampling module and a voltage sampling module. The current sampling module is used to acquire the current signal of the electron beam, and the voltage sampling module is used to acquire the voltage signal of the power supply unit. The current sampling module includes: a sampling circuit, an amplification circuit, and a voltage-to-current conversion circuit connected in sequence. The sampling circuit is used to acquire the current signal of the electron beam to obtain the acquired voltage signal. The amplification circuit is used to amplify the acquired voltage signal to obtain the amplified voltage signal. The voltage-to-current conversion circuit is used to convert the amplified voltage signal into a sampled current signal and transmit it to the data processing unit. The data processing unit includes: a current-to-voltage conversion circuit, an analog-to-digital conversion circuit, and a control circuit connected in sequence. The current-to-voltage conversion circuit is used to convert the current signal of the sampling unit into a voltage signal and sample it to obtain an analog voltage signal. The analog-to-digital conversion circuit is used to perform analog-to-digital conversion on the analog voltage signal to obtain a digital sampled current signal. The control circuit is used to perform calculations based on the digital sampled current signal and the sampled voltage signal of the power supply unit to obtain a voltage control signal, which is then transmitted to the power supply unit. The power supply unit includes: a first high-voltage generating circuit and a second high-voltage generating circuit. One output terminal of the first high-voltage generating circuit is connected to one output terminal of the second high-voltage generating circuit. The other output terminals of the first and second high-voltage generating circuits serve as output terminals of the power supply unit. The first high-voltage generating circuit is connected to a sampling unit and a data processing unit. The second high-voltage generating circuit is connected to both the sampling unit and the data processing unit. The sampling unit samples the first low-voltage signal from the first high-voltage generating circuit and the second low-voltage signal from the second high-voltage generating circuit. The data processing unit controls the outputs of the first and second high-voltage generating circuits based on the first low-voltage signal sampling signal, the second low-voltage signal sampling signal, and the sampling current signal. The outputs of the first and second high-voltage generating circuits are superimposed in series to serve as the output of the power supply unit.

2. The high-frequency composite pulse electron beam welding beam current feedback control circuit according to claim 1, characterized in that, The sampling circuit includes a sampling sub-circuit and a voltage divider sub-circuit connected in parallel. The sampling sub-circuit is used to acquire the current signal of the electron beam acting on the workpiece, and the voltage divider sub-circuit is used to divide and filter the current signal of the sampled electron beam to obtain the acquired voltage signal.

3. The high-frequency composite pulse electron beam welding beam current feedback control circuit according to claim 1, characterized in that, The amplification circuit includes: a first amplification sub-circuit, a voltage follower sub-circuit, a second amplification sub-circuit, and a third amplification sub-circuit connected in sequence. The first amplification sub-circuit is used to amplify the acquired voltage signal for the first time; the voltage follower sub-circuit is used to follow the first amplification result of the first amplification sub-circuit; the second amplification sub-circuit is used to perform impedance isolation and a second amplification on the follower output result of the voltage follower sub-circuit; and the third amplification sub-circuit is used to amplify the second amplification result of the second amplification sub-circuit for the third time to obtain an amplified voltage signal.

4. The high-frequency composite pulse electron beam welding beam current feedback control circuit according to claim 3, characterized in that, The first amplification sub-circuit includes a high-speed instrumentation amplifier; the second amplification sub-circuit includes a high-speed isolation amplifier; and the third amplification sub-circuit includes a differential amplifier.

5. The high-frequency composite pulse electron beam welding beam current feedback control circuit according to claim 1, characterized in that, The voltage-to-current conversion circuit includes a current transmitter, which is used to amplify the amplified voltage signal output by the amplifier circuit again and convert the amplification result into a sampled current signal.

6. The high-frequency composite pulse electron beam welding beam current feedback control circuit according to claim 1, characterized in that, The first high-voltage generating circuit and the second high-voltage generating circuit have the same structure, including: a low-frequency pulse bias power supply circuit, an inverter circuit, an isolation transformer, and a high-frequency pulse bias power supply high-voltage circuit connected in sequence. The low-frequency pulse bias power supply circuit is used to output low-voltage DC power, the inverter circuit is used to convert the low-voltage DC power into first AC power, the isolation transformer is used to convert the first AC power into second AC power, and the high-frequency pulse bias power supply high-voltage circuit is used to output high voltage according to the second AC power.

7. A method for beam current feedback control in high-frequency composite pulsed electron beam welding, characterized in that, The method includes: Using a sampling unit, the current signal of the electron beam and the low-voltage signal of the power supply unit are acquired, and the sampled current signal and sampled voltage signal are amplified and processed respectively to obtain sampled data, which includes the sampled current signal of the electron beam and the sampled voltage signal of the power supply unit. Using a data processing unit, pulsed electron beam parameters are set, and a voltage control signal is output according to the beam-bias voltage lookup table to control the low-voltage output of the power supply unit; and the data processing unit performs calculations on the sampled data to adjust the voltage control signal, and then adjusts the low-voltage output of the power supply unit based on the adjusted voltage control signal. The power supply unit is controlled by the voltage control signal to adjust the low-voltage output and then inverts and converts the low-voltage output to output a high-voltage output; and The electron beam is controlled based on the high voltage output of the power supply unit; The processing and calculation of the sampled data specifically includes: Statistical sampling data distribution range; Calculate the second integral value of the sampled data within one computation cycle; Within one operation cycle, the first integral value of the sampled data for each high-frequency pulse beam cycle is calculated to obtain the effective integral value, and the maximum and minimum effective integral values ​​within one operation cycle are obtained. Based on the maximum effective integral value, the data distribution interval corresponding to the maximum effective integral value, the minimum effective integral value, the data distribution interval corresponding to the minimum effective integral value, and the high-frequency pulse parameters, the estimated values ​​of the beam parameters are calculated. The third integral of the beam parameter estimate is calculated. When the first deviation rate between the third integral and the second integral meets the requirements, the beam parameter estimate is valid. The valid beam parameter estimate is used for calculation, and the output voltage control signal is given to the power supply unit to adjust the low voltage output of the power supply unit.

8. The high-frequency composite pulse electron beam welding beam current feedback control method according to claim 7, characterized in that, The process of processing and calculating the sampled data using the data processing unit further includes: Set a second time period, calculate the second deviation rate between the estimated beam parameter value and the set value within the second time period, and update the beam-bias comparison table when the second deviation rate is less than the second deviation rate threshold.

9. The high-frequency composite pulse electron beam welding beam current feedback control method according to claim 7, characterized in that, Calculate the maximum and minimum effective integrals within one computation cycle, including: Within one operation cycle, calculate the first integral value of the sampled data for each high-frequency pulse beam cycle; When the rate of change between the first integral value of the current period and the first integral value of the previous period is less than the rate of change threshold, the first integral value of the current period is marked as a valid integral value. From a dataset of valid integral values ​​in a computation cycle, obtain the maximum and minimum valid integral values.

10. The high-frequency composite pulse electron beam welding beam current feedback control method according to claim 7, characterized in that, The calculated estimated beam parameters include: A beam current value is obtained from the data distribution interval corresponding to the maximum effective integral value. Combined with the maximum effective integral value and the set beam current parameters, the first set of estimated beam current parameters is calculated, including the estimated peak current value. I p Peak-to-peak current estimation value I pp ; A beam current value is obtained from the data distribution interval corresponding to the minimum effective integral value. Combined with the minimum effective integral value and the set beam current parameters, a second set of estimated beam current parameters is calculated, including the estimated base current value. I b Estimated peak current of the base stack I bp .

11. The high-frequency composite pulse electron beam welding beam current feedback control method according to claim 10, characterized in that, A beam value is obtained from the data distribution range, including: The sampled data are statistically analyzed using a distribution histogram. A value is taken from the interval with the most data in the distribution histogram of the sampled data and used as a beam value.

12. The high-frequency composite pulse electron beam welding beam current feedback control method according to claim 11, characterized in that, Calculate the estimated peak-to-peak current. I pp ,include: From the interval with the most sampled values ​​in the distribution histogram of the sampled data corresponding to the maximum effective integral value, a value is obtained as a beam value. I 1. Assuming the beam current value I 1 represents the estimated peak current. I p The peak-to-peak current estimate is then calculated using the following formula. I pp : I pp = ( S H，MAX f H - I 1 (1 - δ H )) / δ H ； Based on peak current estimation I p Peak-to-peak current estimation value I pp The two values ​​are compared to determine the final peak current estimate. I p Or peak-to-peak current estimation value I pp ; like( S H，MAX f H - I 1 (1 - δ H )) / δ H Greater than or equal to I 1. Then the following assumptions hold true: I p = I 1、 I pp = ( S H，MAX f H - I 1 (1 - δ H )) / δ H ； like( S H，MAX f H - I 1 (1 - δ H )) / δ H Less than I 1. Then the following assumption is not true: I pp = I 1、 I p = ( S H，MAX f H - I 1 δ H ) / (1 - δ H )； In the formula, S H，MA This represents the maximum effective integral. f H Indicates the frequency of a high-frequency pulse. δ H This indicates the duty cycle of the high-frequency pulse.

13. The high-frequency composite pulse electron beam welding beam current feedback control method according to claim 11, characterized in that, Calculate the estimated peak current of the base stack. I bp ,include: From the interval with the most sampled values ​​in the distribution histogram of the sampled data corresponding to the minimum effective integral, a value is obtained as a beam value. I 1. Assuming the beam current value I 1 represents the estimated base current value. I b The estimated value of the base stack peak current is then calculated using the following formula. I bp : I bp = ( S H，MIN f H - I 1 (1 - δ H )) / δ H ， Based on the reference current estimate I b Estimated peak current of the base stack I bp The two values ​​are compared to determine the final reference current estimate. I b Or the estimated peak current of the base stack I bp ; like( S H，MIN f H - I 1 (1 - δ H )) / δ H Greater than or equal to I 1. Then the following assumptions hold true: I b = I 1. I bp = ( S H，MIN f H - I 1 (1 - δ H )) / δ H ; like( S H，MIN f H - I 1 (1 - δ H )) / δ H Less than I 1. Then the following assumption is not true: I bp = I 1. I b = ( S H，MIN f H - I 1 δ H ) / (1 - δ H ); where, S H，MIN This represents the minimum effective integral. f H Indicates the frequency of a high-frequency pulse. δ H This indicates the duty cycle of the high-frequency pulse.

14. The high-frequency composite pulse electron beam welding beam current feedback control method according to claim 7, characterized in that, The statement that the estimated beam parameters are valid when the first deviation rate between the third integral and the second integral meets the requirements includes: Based on the estimated values ​​of the first set of beam parameters and the estimated values ​​of the second set of beam parameters, calculate the third integral of the estimated beam parameters, and calculate the first deviation rate between the third integral value and the second integral value; If the first deviation rate is less than the first deviation rate threshold, the estimated beam parameters are valid. If the first deviation rate is greater than or equal to the first deviation rate threshold, the first integral value, the first set of estimated beam parameters, the second set of estimated beam parameters, and the third integral of the estimated beam parameters for each high-frequency pulse beam cycle are recalculated within one operation cycle to obtain effective estimated beam parameters.

15. The high-frequency composite pulse electron beam welding beam current feedback control method according to claim 7, characterized in that, The low-voltage output includes: a first low-voltage output and a second low-voltage output; The step of processing the sampled data, adjusting the voltage control signal, and thereby adjusting the low-voltage output of the power supply unit includes: The first low voltage and the second low voltage are sampled. Based on the sampled first low voltage and the second low voltage, calculations are performed, and a voltage control signal is output to adjust the output of the first low voltage and the second low voltage respectively.

16. The high-frequency composite pulse electron beam welding beam current feedback control method according to claim 7 or 8, characterized in that, The data processing unit also performs processing and calculations on the sampled data, including: A first set time period is set. After the first set time period is exceeded, the effective beam current parameter estimation value is used to perform calculations and output a voltage control signal to control the low voltage output.

17. A high-frequency composite pulse electron beam welding beam current feedback control system, characterized in that, include: The high-frequency composite pulse electron beam welding beam current feedback control circuit and electron beam generating device as described in any one of claims 1-6, wherein the electron beam generating device is connected to a power supply unit and a sampling unit, and is used to generate an electron beam acting on the workpiece according to the output voltage of the power supply unit; the sampling unit is used to collect the current signal of the electron beam current and the voltage signal of the power supply unit, and amplify the current signal and the voltage signal respectively to obtain a sampled current signal and a sampled voltage signal; the data processing unit performs calculations based on the sampled current signal and the sampled signal of the power supply unit, and outputs a voltage control signal, wherein the voltage control signal controls the output voltage of the power supply unit; the power supply unit is used to adjust the low-voltage output of the power supply unit according to the voltage control signal output by the data processing unit, and the power supply unit outputs a high voltage after inverting and converting the low-voltage output, wherein the high voltage output of the power supply unit is transmitted to the electron beam generating device, and the electron beam generating device controls the electron beam current according to the high voltage output of the power supply unit.

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