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

Abstract

The embodiment of the invention relates to the technical field of electron beam welding, and discloses a high-frequency composite pulse electron beam welding beam feedback control circuit, method and system. The control circuit comprises a sampling unit, a data processing unit and a power supply unit. The data processing unit is connected with the sampling unit and the power supply unit. The sampling unit is used for collecting a current signal of the electron beam current and a voltage signal of the power supply unit to obtain a sampling signal; the data processing unit performs operation according to the sampling signal and outputs a voltage control signal, and the voltage control signal is used for adjusting the output voltage of the power supply unit; the power supply unit is used for adjusting 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 and then outputs high voltage, and the output high voltage of the power supply unit is used for controlling the electron beam current. According to the invention, the problem that precise control cannot be carried out during electron beam welding is solved, so that the control of the electron beam is more precise.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of electron beam welding, and in particular to a high-frequency composite pulse electron beam welding beam feedback control circuit, method and system. Background Art

[0002] In the field of welding technology, high-frequency composite pulse electron beam welding is an advanced welding technology that combines the characteristics of high-frequency and low-frequency pulses to achieve more precise control of the welding process to improve welding quality and efficiency. In the electron beam additive manufacturing process, this composite pulse electron beam welding technology has a significant impact on welding quality and efficiency. The low-frequency pulse is mainly used to provide a stable melting rate and heat input, while the high-frequency pulse is used to more accurately control the droplet transition and the dynamic behavior of the molten pool.

[0003] In low-frequency pulsed electron beam welding systems within 1kHz, current sampling in the high-voltage acceleration power supply circuit in the high-voltage oil tank is generally used for beam feedback control. In addition, some designs use the output voltage sampling of the bias grid in the high-voltage oil tank to estimate the beam through the calculation model and then perform beam feedback control. However, since the high-voltage oil tank requires the use of a high-voltage isolation transformer for energy transmission and high-voltage isolation, when a higher pulse frequency beam is output, the inverter AC voltage on the transformer will produce very large electromagnetic and conduction interference to the signal measurement, resulting in inaccurate measurement.

[0004] In the constant current electron beam feedback system, an analog PID controller is used to change the bias value, thereby controlling the beam size well. In conventional pulse electron beam welding, if analog PID control is used, the feedback delay time has a great influence on the upper limit of the output pulse frequency. Therefore, when outputting a higher pulse frequency, most of them currently use the "beam current-bias voltage comparison table method" to control the bias output in a closed loop and the beam current in an open loop. This method is also called beam coarse adjustment. However, as the pulse frequency of the beam continues to increase, 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 continues to increase. Summary of the invention

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

[0006] To solve the above technical problems, at least one embodiment of the present application provides a high-frequency composite pulse electron beam welding beam feedback control circuit, including a sampling unit, a data processing unit and a power supply unit, the data processing unit is respectively connected to the sampling unit and 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 respectively amplifies the current signal and the voltage signal 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 for adjusting the output voltage of the power supply unit. The power supply unit adjusts the output voltage based on the output voltage control signal to control the electron beam.

[0007] At least one embodiment of the present application also provides a high-frequency composite pulse electron beam welding beam feedback control method, including: setting pulse electron beam parameters, outputting first low voltage and second low voltage parameters according to a beam-bias voltage comparison table; sampling the first low voltage, the second low voltage and the electron beam current signal, shaping the collected data to obtain sampled data; counting the distribution interval of the sampled data; calculating the second integral value of the sampled data within an operation cycle; calculating the first integral value of the sampled data of each high-frequency pulse beam cycle within an operation cycle to obtain an effective integral value, and obtaining an effective integral maximum value and an effective integral minimum value within an operation cycle; calculating a beam parameter estimation value according to the effective integral maximum value, the data distribution interval corresponding to the effective integral maximum value, the effective integral minimum value, the data distribution interval corresponding to the effective integral minimum value, and the high-frequency pulse parameters, calculating the third integral of the beam parameter estimation value, and when the first deviation rate between the third integral and the second integral meets the requirements, the beam parameter estimation value is valid, and the effective beam parameter estimation value is used for operation to adjust the output of the first low voltage and the second low voltage.

[0008] At least one embodiment of the present application also provides a high-frequency composite pulse electron beam welding beam feedback control system, including the high-frequency composite pulse electron beam welding beam feedback control circuit and the electron beam generating device as described above, the electron beam generating device is connected to the power supply unit and the 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, convert the electron beam current signal into a voltage for collection, and divide and amplify the collected voltage signal, and convert the amplified voltage signal into a current to obtain a sampled current signal; the data processing unit uses the high-frequency composite pulse electron beam welding beam feedback control method as described above according to the sampled current signal and the sampling signal of the power supply voltage, outputs a voltage control signal, and controls the output voltage of the power supply unit.

[0009] Compared with the prior art, the high-frequency composite pulse electron beam welding beam feedback control circuit, method and system provided in the embodiments of the present application adopt amplification and integration operations on the sampled data to obtain effective beam parameter estimates, and then perform PID operations based on the effective beam parameter estimates to output a control signal to control the output of the power supply unit, thereby solving the feedback control problem of the beam and achieving precise control of the beam.

[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 are collected separately as feedback basis to ensure the accuracy of feedback control.

[0011] In addition, the current sampling module includes: a sampling circuit, an amplifying circuit, and a voltage-current conversion circuit connected in sequence, wherein the sampling circuit is used to collect the current signal of the electron beam to obtain a collected voltage signal, the amplifying circuit is used to amplify the collected voltage signal to obtain an amplified voltage signal, and the voltage-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 current sampling data of the beam is amplified, converted, and output in the form of current, which extends the signal transmission distance and reduces the loss during the signal transmission process.

[0012] In addition, the sampling circuit includes: a sampling subcircuit and a voltage dividing subcircuit connected in parallel, the sampling subcircuit is used to collect the beam signal acting on the workpiece, and the voltage dividing subcircuit is used to divide and filter the sampled beam signal to obtain a collected voltage signal. The voltage dividing circuit is used to reduce the amplitude of the input signal.

[0013] In addition, the amplifier circuit includes: a first amplifier subcircuit, a voltage follower subcircuit, a second amplifier subcircuit and a third amplifier subcircuit connected in sequence, the first amplifier subcircuit is used to perform the first amplification of the collected voltage signal; the voltage follower subcircuit is used to follow the first amplification result of the first amplifier subcircuit; the second amplifier subcircuit is used to perform impedance isolation and amplification, and the third amplifier subcircuit is used to perform the third amplification to obtain an amplified voltage signal. After amplification and isolation processing, the differential mode noise in the signal is reduced, and the high voltage fault is prevented from damaging the subsequent circuit.

[0014] In addition, the first amplifying subcircuit includes a high-speed instrumentation amplifier to reduce differential mode noise in the signal; the second amplifying subcircuit includes a high-speed isolation amplifier; and the third amplifying subcircuit includes a differential amplifier to prevent high-voltage faults from damaging subsequent circuits.

[0015] In addition, the voltage-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 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-voltage conversion circuit, an analog-to-digital conversion circuit and a control circuit connected in sequence, the current-voltage conversion circuit is used to convert the current signal of the sampling unit into a voltage signal and perform sampling 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 sampling current signal, and the control circuit is used to perform calculations based on the digital sampling current signal and the sampling voltage signal of the power supply unit to obtain a voltage control signal and transmit it to the power supply unit. The sampling data is calculated, and an effective beam parameter estimation value is output, and feedback control is performed, thereby improving the accuracy of beam control.

[0017] In addition, the power supply unit includes: a first high-voltage generating circuit and a second high-voltage generating circuit, an output end of the first high-voltage generating circuit is connected to an output end of the second high-voltage generating circuit, another output end of the first high-voltage generating circuit and another output end of the second high-voltage generating circuit are respectively used as output ends of the power supply unit, the first high-voltage generating circuit is respectively connected to a sampling unit and a data processing unit, the second high-voltage generating circuit is respectively connected to a sampling unit and a data processing unit, the sampling unit samples a first low-voltage signal of the first high-voltage generating circuit and a second low-voltage signal of the second high-voltage generating circuit respectively, and the data processing unit controls the output of the first high-voltage generating circuit and the output of the second high-voltage generating circuit according to the first low-voltage signal sampling signal, the second low-voltage signal sampling signal and the sampling current signal. The low-voltage output is adjusted to control the high-voltage output, thereby reducing the difficulty of feedback control.

[0018] In addition, 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 direct current, the inverter circuit is used to convert the low-voltage direct current into the first alternating current, the isolation transformer is used to convert the first alternating current into the second alternating current, and the high-frequency pulse bias power supply high-voltage circuit is used to output high voltage according to the second alternating current. The low voltage is converted into high voltage, thereby achieving the purpose of high-voltage output.

[0019] The high-frequency composite pulse electron beam welding beam feedback control method of the present application comprises: using a sampling unit to collect the current signal of the electron beam and the low-voltage signal of the power supply unit, and respectively amplifying and processing the sampled current signal and the sampled voltage signal to obtain sampling data, wherein the sampling data comprises 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 pulse electron beam parameters, and outputting a voltage control signal according to a beam current-bias voltage comparison table, so as 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, adjust the voltage control signal, and then adjust 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 high voltage after inverting the low-voltage output; and controlling the electron beam based on the output high voltage of the power supply unit.

[0020] The method of the present application first starts the low-voltage output using a beam bias voltage comparison table, performs sampling and data processing by a sampling unit, and uses a data processing unit to adjust the output of a power supply unit according to the sampled data, thereby achieving feedback control of the beam and improving the accuracy of beam control.

[0021] In addition, the processing operation of the sampled data specifically includes: counting the distribution interval of the sampled data; calculating the second integral value of the sampled data within a calculation cycle; calculating the first integral value of the sampled data of each high-frequency pulse beam cycle within a calculation cycle to obtain an effective integral value, and obtaining an effective integral maximum value and an effective integral minimum value within a calculation cycle; calculating the beam parameter estimation value according to the effective integral maximum value, the data distribution interval corresponding to the effective integral maximum value, the effective integral minimum value, the data distribution interval corresponding to the effective integral minimum value, and the high-frequency pulse parameters; calculating the third integral of the beam parameter estimation value, when the first deviation rate between the third integral and the second integral meets the requirements, the beam parameter estimation value is valid, and the effective beam parameter estimation value is used for operation, and a voltage control signal is output to the power supply unit for adjusting the low-voltage output of the power supply unit. The actual sampled data cannot be accurately and timely feedback controlled due to factors such as delay and interference. The method processes the sampled data and then performs integral operation to obtain an effective beam parameter estimation value, and performs feedback control, thereby improving the accuracy of feedback control.

[0022] In addition, the processing operation of the sampled data by the data processing unit further includes: calculating a second deviation rate between the estimated value of the beam parameter and the set value within a second set time period, and updating the beam-bias voltage comparison table when the second deviation rate is less than a second deviation rate threshold. The comparison table is updated according to the estimated value of the beam parameter, so that the comparison table has higher accuracy and the next output control is more accurate.

[0023] In addition, the calculation of the effective maximum integral value and the effective minimum integral value within an operation cycle includes: within an operation cycle, calculating the first integral value of the sampling data of each high-frequency pulse beam cycle, when the rate of change of the first integral value of the current cycle and the first integral value of the previous cycle is greater than a set value, marking the first integral value of the current cycle as an effective integral value, and obtaining the effective maximum integral value and the effective minimum integral value from the effective integral value data set in an operation cycle. Only the maximum value and the minimum value are retained for the high-frequency pulses within the operation cycle, the maximum value is used to correspond to the high frequency, and the minimum value is used to correspond to the low frequency, thereby ensuring the data integrity of the high and low frequency operations.

[0024] In addition, the calculation of the beam parameter estimation value includes: obtaining a beam current value from the data distribution interval corresponding to the effective integral maximum value, combining the effective integral maximum value and the set beam parameters to calculate a first group of beam parameter estimation values, including the peak current estimation value I p , peak-to-peak current estimation value I pp ; Obtain a beam parameter from the data distribution interval corresponding to the effective integral minimum value, and combine the effective integral minimum value and the set beam parameter to calculate the second set of beam parameter estimates, including the base current estimate I b , estimated value of base stack peak current I bp Through the integration operation, the burrs of the signal are smoothed out, the timing delay of the signal is ignored, and the accuracy of the data is guaranteed.

[0025] In addition, the step of obtaining a beam current value from the data distribution interval includes: using a distribution histogram to perform statistics on the sampled data, and taking a value from the interval with the largest amount of data in the distribution histogram of the sampled data as a beam current value. Using a histogram to obtain the beam current value more intuitively, and taking a value from the interval with the largest amount of data as the beam current value, ensures the probability of the beam current value appearing and improves the reliability of the data.

[0026] In addition, the peak-to-peak current estimation value I pp , including: obtaining a value as a beam current value I from the interval with the largest number of sampled values ​​in the distribution histogram of the sampled data corresponding to the maximum effective integral value 1 , assuming the beam current value I 1 Estimated value of peak current I p , then the peak-to-peak current estimate value I is calculated by the following formula pp :

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

[0028] Estimated value I based on the peak current p And the peak-to-peak current estimate I pp The two values ​​are judged and the peak current estimation value I is finally determined. p Or the peak-to-peak current estimate I pp ;

[0029] If (S H，MAX f H -I 1 (1-δ H )) / δ H Greater than or equal to I 1 , then the assumption holds:

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

[0031] If (S H，MAX f H -I 1 (1-δ H )) / δ H Less than I 1 , then the assumption does not hold:

[0032] I pp =I 1 ,I p =(S H，MAX f H -I 1 δ H ) / (1-δ H );(3);Wherein, S H，MA represents the maximum effective integral value, f H represents the high-frequency pulse frequency, δ H Indicates the duty cycle of high-frequency pulses.

[0033] In addition, the calculation base stack peak current estimation value I bp , including: obtaining a value as a beam current value I from the interval with the largest number of sampled values ​​in the distribution histogram of the sampled data corresponding to the minimum effective integral value 1 , assuming the beam current value I 1 The estimated value of the reference current I b , then the base stack peak current estimate I is calculated by the following formula bp :

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

[0035] Estimated value I based on reference current b and the estimated base stack peak current I bp The two values ​​are judged and the reference current estimation value I is finally determined. b Or the estimated base stack peak current I bp ;

[0036] If (S H，MIN f H -I 1 (1-δ H )) / δ H Greater than or equal to I 1 , then the assumption holds:

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

[0038] If (S H，MIN f H -I 1 (1-δ H )) / δ H Less than I 1 , then the assumption does not hold:

[0039] I bp =I 1 ,I b =(S H，MIN f H -I 1 δ H ) / (1-δ H );(6);Wherein, S H，MIN represents the effective minimum integral value, f H represents the high-frequency pulse frequency, δ H Indicates the duty cycle of high-frequency pulses.

[0040] The values ​​are taken from the histogram, combined with the set parameters for calculation, and the estimated values ​​of the beam parameters are obtained according to the size relationship between the peak value and the base value, which are used for subsequent feedback control, thus avoiding the failure to perform feedback control in a timely manner due to the delay of the actual sampling data.

[0041] In addition, when the first deviation rate between the third integral and the second integral meets the requirement, the beam parameter estimation value is valid, including: calculating the third integral of the beam parameter estimation value according to the first group of beam parameter estimation values ​​and the second group 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 of the sampling data of each high-frequency pulse beam cycle, the first group of beam parameter estimation values, the second group of beam parameter estimation values ​​and the third integral of the beam parameter estimation value within one operation cycle, to obtain a valid beam parameter estimation value. The beam parameter estimation value is evaluated to ensure the accuracy of the estimation value.

[0042] In addition, after setting the pulse electron beam current parameters and outputting the first low voltage and the second low voltage parameters according to the beam current-bias voltage comparison table, the first low voltage and the second low voltage are sampled; the first operation is performed according to the sampled first low voltage and the second low voltage, and a voltage control signal is output to control the output of the first low voltage and the second low voltage. The low voltage output is controlled according to the comparison table, and the output is roughly adjusted to improve the output accuracy.

[0043] In addition, the low-voltage output includes: a first low-voltage output and a second low-voltage output; the operation and processing of the sampled data, adjusting the voltage control signal, and then adjusting the low-voltage output of the power supply unit include: sampling the first low voltage and the second low voltage, performing operations based on the sampled first low voltage and the second low voltage, outputting voltage control signals, and adjusting the outputs of the first low voltage and the second low voltage respectively. The use of double voltage superposition can expand the high-voltage range. In addition, the use of the data processing unit to process and calculate the sampled data also includes: setting a first set time period, and after exceeding the first set time period, using a valid beam parameter estimation value to perform operations, output a voltage control signal, and control the low-voltage output. After the set time period, the beam signal is stable, and then the operation is performed, which improves the accuracy of the low-voltage output.

[0044] The high-frequency composite pulse electron beam welding beam feedback control system of the present application comprises: the high-frequency composite pulse electron beam welding beam feedback control circuit and the electron beam generating device described in the present application, the electron beam generating device is connected with the power supply unit and the 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 respectively amplify the current signal and the voltage signal to obtain the sampled current signal and the sampled voltage signal; the data processing unit calculates according to the sampled current signal and the sampled voltage signal of the power supply unit, and outputs a voltage control signal, and the voltage control signal 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, and the power supply unit outputs high voltage after inverting and converting the low-voltage output, and the output high voltage of the power supply unit is transmitted to the electron beam generating device, and the electron beam generating device controls the electron beam according to the high voltage. The sampling resistor is set inside the vacuum chamber, and the grounded chamber shell can effectively shield external interference. The accuracy of the sampling signal is ensured. By performing a series of operations on the sampling data, precise control of the beam is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

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

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

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

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

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

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

[0052] Figure 7It is a schematic diagram of histogram data distribution provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it can be understood by those skilled in the art that in the embodiments of the present invention, many technical details are provided to enable readers to better understand the present invention. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present invention can be implemented.

[0054] Embodiment 1:

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

[0056] Compared with the prior art, the implementation mode of the present invention adopts 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 processing, and then convert the amplified result into current and transmit it to the data processing unit. The data processing unit performs calculations to obtain effective beam parameter estimation values ​​and controls the output of the power supply unit, thereby solving the feedback control problem of the beam.

[0057] The implementation details of the beam feedback control circuit of this embodiment are described in detail below. The following content is only provided for easy understanding of the implementation details and is not necessary for implementing this solution.

[0058] An embodiment of the present invention provides a high-frequency composite pulse electron beam welding beam feedback control circuit, comprising: a sampling unit, a data processing unit and a power supply unit, wherein the data processing unit is connected to the sampling unit and the power supply unit respectively, the sampling unit is used to collect the current signal of the electron beam 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 voltage signal, and outputs a voltage control signal, and the voltage control signal 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, and the power supply unit outputs high voltage after inverting and converting the low-voltage output, and the output high voltage of the power supply unit is used to control the electron beam.

[0059] The sampling unit is used to collect the current signal of the electron beam, divide and amplify the collected current signal to obtain a sampled current signal, which is a digital voltage signal; collect the voltage signal of the power supply unit to obtain a sampled voltage signal, which is also a digital voltage signal, and transmit the sampled current signal and the sampled voltage signal to the data processing unit respectively. The data processing unit performs calculations based on the collected sampled current signal and sampled voltage signal, and outputs a voltage control signal for adjusting the voltage of the power supply unit. The power supply unit outputs the adjusted voltage based on the voltage control signal to control the electron beam, thereby realizing feedback control of the welding beam, such as Figure 1 shown.

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

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

[0062] The data processing unit includes a current-voltage conversion circuit, an analog-to-digital conversion circuit and a control circuit connected in sequence. The current-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 sampling current signal. The control circuit is used to perform calculations based on the digital sampling current signal and the sampling voltage signal of the power supply unit to obtain a voltage control signal and transmit it 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 collect the beam current size, including a sampling subcircuit and a voltage divider subcircuit connected in parallel. The sampling subcircuit is used to collect the beam current size acting on the workpiece and prevent transient high voltage. The voltage divider subcircuit is used to divide and filter the sampling signal to obtain a collected voltage signal.

[0065] The sampling subcircuit includes a collection 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 transient voltage increase caused by the transient current.

[0066] The sampling resistor uses a non-inductive resistor to avoid waveform distortion of the high-frequency pulse beam signal to be measured, and the transient suppression diode is used to protect the subsequent circuit to avoid overvoltage damage.

[0067] The voltage divider subcircuit includes a resistor-capacitor voltage divider combination, which is used to filter and divide the sampling signal to effectively suppress common-mode noise.

[0068] The amplifier circuit is used to perform multi-stage amplification on the collected voltage signal to obtain an amplified voltage signal.

[0069] It includes a first amplifying sub-circuit, a voltage following sub-circuit, a second amplifying sub-circuit and a third amplifying sub-circuit which are connected in sequence.

[0070] The first amplification subcircuit includes a high-speed instrumentation amplifier, which is used to accurately amplify the collected voltage signal, thereby ensuring accurate measurement of the pulse beam signal while effectively suppressing common mode noise.

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

[0072] The second amplifying subcircuit includes a high-speed isolation amplifier, which is used for impedance isolation and amplification, electrically isolating the front and rear stage circuits, and protecting the safety of the rear stage circuit.

[0073] The third amplifying sub-circuit includes a differential amplifier, which is used for further amplification to obtain an amplified voltage signal.

[0074] The voltage-to-current conversion circuit is used to convert the amplified voltage signal into a current signal, including a current transmitter, which converts the voltage signal into a current signal for long-distance transmission, thereby reducing losses.

[0075] The current-to-voltage conversion circuit includes a conversion resistor, which is used to convert current into voltage for long-distance transmission, thereby reducing loss.

[0076] The analog-to-digital conversion circuit converts the voltage analog quantity on the conversion resistor into a digital quantity to obtain a sampling current signal.

[0077] The control circuit is used to receive the sampling current signal output by the sampling unit and the sampling voltage signal output by the power supply unit, perform operations, obtain the voltage control signal, control the output voltage of the power supply unit, thereby controlling the electron beam current and realizing 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 a 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 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 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, and its output is connected to the input end 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, and its output is connected to the input end 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 output in series to obtain a control voltage for the electron beam current.

[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 collection signal and the second low voltage collection signal respectively to obtain a sampled voltage signal. The sampled voltage signal includes the first low voltage sampling voltage signal and the second low voltage sampling voltage signal.

[0084] The voltage control signal output by the control module is 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, and to realize the output control of the first high voltage and the second high voltage.

[0085] Embodiment 2

[0086] The implementation manner of the present invention is a detailed description of the above-mentioned embodiment 1.

[0087] like Figure 2 As shown, the sampling subcircuit includes a sampling resistor R9 and a transient suppression diode (TVS) D1. The sampling resistor R9 is connected in parallel with the TVS tube D1, one end of which is used to connect to the beam output end acting on the workpiece, and the other end is connected to the ground. The current flowing through the resistor R9 is collected to obtain a sampling voltage.

[0088] The voltage divider subcircuit includes a capacitor series combination of capacitors C4 / C12 and a resistor series combination of resistors R5 / R16. The capacitor series combination and the resistor series combination are connected in parallel with the sampling subcircuit. The series points of the capacitor series combination and the resistor series combination are connected to the ground terminal GND1. Capacitor C4 is connected in parallel with resistor R5, and capacitor C12 is connected in parallel with resistor R16. Capacitors C4 / C12 are used to divide and filter the sampling voltage, and resistors R5 / R16 are used to divide the sampling voltage. The use of resistor-capacitor voltage divider can effectively suppress common-mode noise.

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

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

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

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

[0093] The second amplification 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 the resistor R12 and one end of the capacitor C10, and its AIN terminal is connected to one end of the resistor R15 and the other end of the capacitor C10. The other end of the resistor R15 is connected to one end of the resistor R18 and one end of the resistor R21. The other end of the resistor R21 is connected to the 3.3V power supply terminal. The other end of the resistor R18 is connected to the ground GND1. The capacitor C15 is connected in parallel between the 3.3V power supply and the ground GND1 for filtering the 3.3V power supply.

[0094] The series combination of resistor R21 and resistor R18 divides the 3.3V voltage, and applies the divided voltage result 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 terminal and AON terminal serve as the output terminals of the second amplification sub-circuit.

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

[0097] The series combination of the resistor R28 and the resistor R29 is used to divide the output signal of the AOP end.

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

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

[0100] Operational amplifier U6 and transistor Q1 convert the input voltage into current, and use the characteristics of current signal with small error, strong anti-interference ability and suitability for long-distance transmission to increase the transmission distance.

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

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

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

[0104] Embodiment three:

[0105] An embodiment of the present invention provides a high-frequency composite pulse electron beam welding beam feedback control system, comprising a high-frequency composite pulse electron beam welding beam feedback control circuit and an electron beam generating device, 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 a 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 respectively amplify the current signal and the voltage signal 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 sampling signal of the power supply unit, and outputs a voltage control signal, and 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 high voltage after inverting and converting the low-voltage output, and the output high voltage of the power supply unit is transmitted to the electron beam generating device, and the electron beam generating device controls the electron beam according to the high voltage.

[0106] like Figure 1 As shown, a high-frequency composite pulse electron beam welding beam 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 according to the output voltage of the power supply unit to act 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, convert the electron beam current signal into voltage for collection, divide and amplify the collected voltage signal, and convert the amplified voltage signal into current to obtain a sampled current signal, and use the characteristics of small error and strong anti-interference ability during current signal transmission to perform long-distance transmission.

[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 a generated voltage of the electron beam current.

[0108] The sampling unit also samples the first low voltage and the second low voltage of the power supply unit to obtain a first low voltage sampling voltage signal and a 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 achieving feedback control of the electron beam current.

[0110] Embodiment 4

[0111] The implementation manner of the present invention is a detailed description of the above-mentioned embodiment 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 the first low voltage into a first high voltage, the second high-voltage generating circuit is used to convert the second low voltage into a second high voltage, the first high voltage and the second high voltage are superimposed in series and output to obtain 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 alternating current. The first isolation transformer isolates and transforms the first alternating current to obtain a second alternating current. The first high-frequency pulse bias power supply high-voltage circuit generates a first high voltage U3 according to the second alternating current. The first low voltage U1 and the first high voltage U3 are direct currents.

[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 is used to output a second low voltage U2, the second inverter circuit converts the second low voltage U2 into a third alternating current, the second isolation transformer isolates and transforms the third alternating current to obtain a fourth alternating current, and the second high-frequency pulse bias power supply high-voltage circuit generates a second high voltage U according to the fourth alternating current, and the second low voltage U2 and the second high voltage U4 are direct currents.

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

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

[0117] The electron beam generating device comprises a high-voltage acceleration power supply, a filament heating power supply and an electron beam generator. The negative output terminal of the high-voltage acceleration power supply is connected to the positive output terminal of the third high voltage U5, and the positive output terminal thereof is grounded. The positive output terminal of the third high voltage U5 is connected to the series point of series resistors R1 / R2. The series combination of series resistors R1 / R2 is connected in parallel between the positive output terminal and the negative output terminal 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 comprises a filament 3, an insulating block 4, a bias grid 5, a high-voltage anode 6, a coaxial coil 7, an stigmation coil 8, a vacuum cabin 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 moving platform 18. The filament heating power supply is pressurized at both ends of the filament 3 to generate an electron beam. The bias grid 5, the high-voltage anode 6, the coaxial coil 7, the anti-stigmation coil 8, the focusing coil 10, and the deflection coil 11 respectively accelerate the electron beam, so that the electron beam 12 acts on the workpiece 15, and the conduction current and the penetration current flow through the backing plate 16 through the beam sampling resistor 14, and the beam sampling resistor 14 returns to the positive electrode of the high-voltage acceleration power supply through the moving platform 18 connected to the ground.

[0118] The beam sampling resistor 14 is arranged in the vacuum chamber. The vacuum chamber shell connected to the ground can well shield the external interference. The signal input end of the sampling circuit is respectively connected to the pad under the workpiece and the grounded moving platform. The pad and the moving platform are electrically isolated by the insulating plate, which ensures that the sampling signal has low noise and no distortion.

[0119] Embodiment 5

[0120] The embodiment of the present invention provides a high-frequency composite pulse electron beam welding beam feedback control method, comprising using a sampling unit to collect a current signal of an electron beam and a low-voltage signal of a power supply unit, and amplifying the sampled current signal and the sampled voltage signal respectively to obtain sampling data, wherein the sampling data comprises a sampled current signal of the electron beam and a sampled voltage signal of the power supply unit;

[0121] Using a data processing unit, setting pulse electron beam parameters, outputting a voltage control signal according to a beam current-bias voltage comparison table, and controlling 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;

[0122] The power supply unit is controlled by the voltage control signal, adjusts the low voltage output, and outputs high voltage after inverting the low voltage output; and

[0123] The electron beam current is controlled based on the output high voltage of the power supply unit.

[0124] The low pressure includes a first low pressure and a second low pressure.

[0125] Set the pulse electron beam parameters, adjust the first low voltage and the second low voltage parameters according to the beam current-bias voltage comparison table, quickly adjust the electron beam current to the set value and maintain a stable state, sample the first low voltage and the second low voltage, sample the sampling current signal of the electron beam current, perform data shaping, and in each operation cycle, use the integral value SH and distribution of the sampling data in the high-frequency pulse beam current cycle, combined with the maximum and minimum SH values ​​in the calculation cycle, that is, the maximum value method, to solve the base peak parameter value in the high-frequency composite pulse beam current waveform, fine-tune the electron beam current, and improve the accuracy of the output beam current waveform. In the fine-tuning process, update the bias data of the "beam current-bias voltage comparison table" to improve the accuracy of the coarse adjustment result.

[0126] In a specific embodiment of the present application, the low-frequency pulse beam period is used as the calculation period.

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

[0128] The pulse electron beam parameters are set 49, and the output of the first low voltage and the second low voltage is controlled 51 according to the beam-bias voltage comparison table and the set parameters 50. The first low voltage, the second low voltage 54 and the electron beam current value are sampled 55. According to the first low voltage sampling and the second low voltage sampling value, a first PID operation 52 is performed, and a voltage control signal 53 is output to adjust the output of the first low voltage and the second low voltage, that is, the first low voltage output adjustment, which is the inner loop of the beam feedback, also called the beam coarse adjustment, and the sampled values ​​of the electron beam current value are subjected to data shaping 56, 57 to obtain the sampled data, and the sampled data are calculated, including the block diagrams 58 to 64, to obtain the effective current estimation value, and a second operation 65 is performed according to the effective current estimation value, and a voltage control signal is output to adjust the output of the first low voltage and the second low voltage, that is, the second low voltage output adjustment, also called the beam fine adjustment, and when the effective current estimation value meets the conditions 66, the beam-bias voltage comparison table 67 is updated.

[0129] Specifically, the pulse electron beam parameters include low-frequency pulse beam parameters and high-frequency pulse beam parameters. The low-frequency pulse beam parameters include the base current I b , peak current I p , low frequency f L , low frequency duty cycle δ L , the high frequency pulse beam parameters are base peak current I bp , peak-to-peak current I pp , high frequency f H , high frequency duty cycle δ HThe high-frequency signal is superimposed on the low-frequency signal, and the 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 base stack peak current I bp is the base current I at low frequency b The high-frequency peak current superimposed on the peak current is I pp It is the high-frequency peak current superimposed on the low-frequency peak current. In the first low voltage U1, U p High level, the second low voltage U2 is U pp When the level is low, the corresponding reference current I b is low, the reference current I b The superimposed peak current 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 I p is high, at the peak current I p The peak current I pp .

[0130] The sampling current signal is subjected to data shaping, including linear verification and digital filtering, to obtain sampling data.

[0131] Perform operations on sampled data, including:

[0132] The period of the low frequency pulse beam is 1 / f L The first integral value of the sampling data of each high-frequency pulse in the parameter operation cycle is calculated. When the change rate 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 the change rate threshold, the first integral value of the current high-frequency pulse is considered to be a valid integral value. A valid integral value data set in a parameter operation cycle is obtained, thereby obtaining a valid integral maximum value and a valid integral minimum value. According to the valid integral maximum value, the distribution histogram corresponding to the valid integral maximum value and the high-frequency pulse parameters, the peak current estimation value I is calculated. p And the peak-to-peak current estimate I pp , according to the effective integral minimum value, the distribution histogram corresponding to the effective integral minimum value and the high-frequency pulse parameters, the reference current estimation value I is calculated. b and the estimated base stack peak current I bp, according to the current estimation value, calculate the third integral value of the current estimation value, calculate the second integral value of the sampling data, calculate the first deviation rate between the third integral value and the second integral value, when the first deviation rate is less than the first deviation rate threshold, the current estimation value obtained is valid, according to the valid current estimation value, after being greater than the first set time period, perform a second PID operation, output a voltage control signal, control the output of the first low voltage and the second low voltage, and control the output of the third high voltage, within the second set time period, calculate the second deviation rate between the current estimation value and the set value, when the current estimation value is less than the second deviation rate threshold, update the beam current-bias voltage comparison table.

[0133] Calculates effective integral values ​​and current estimates, including:

[0134] A1. Calculate the period 1 / f of a low-frequency pulse beam L Each high frequency cycle within 1 / f H The first integrated value S of the sampled data H , to obtain a low-frequency pulse beam period 1 / f L The effective integral value data set in the range is used to obtain the effective integral maximum value and the effective integral minimum value from the effective integral value data set. L represents the frequency of the low-frequency pulse beam, f H Indicates the high-frequency pulse frequency;

[0135] A2. Statistical low-frequency pulse beam period 1 / f L Each high frequency cycle within 1 / f H The distribution of the sampling data is used to approximate the estimated beam parameter I by taking the boundary value or the middle value of the area with the largest number of sampling data. 1 or I 1p ;

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

[0137] A4. Calculate a low-frequency pulse beam period 1 / f based on the sampling data L The second integral value S of the internal sampling data L ;

[0138] A5. Calculate the low-frequency pulse beam period 1 / fL The third integral value S of the beam parameter estimation value is C , calculate the third integral value S C and 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 beam parameter estimation value is calculated incorrectly, and the process returns to A1 and starts again; if the first deviation rate is less than the first deviation rate threshold, the beam parameter estimation value is valid, and the process proceeds to the next step;

[0139] A6. After the first set time period, a second PID operation is performed with the estimated value of the beam parameter, and a voltage control signal is output to adjust the output of the first low voltage and the second low voltage;

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

[0141] Specifically, A1 includes:

[0142] Calculate the period 1 / f of a low frequency pulse beam L Each high frequency cycle within 1 / f H The first integrated 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) The rate of change of H , and the rate of change σ H and the change rate threshold σ H,th For comparison, if the rate of change σ H Less than the change rate threshold σ H,th , then mark the current first integral value S Hi is the effective integral value S H , the effective integral value indicates that the current beam is in a stable stage, and the beam waveform in the stable stage is more consistent with a square wave.

[0143] Calculate the period 1 / f of a low frequency pulse beam L The effective integral value S of all high-frequency pulses in H , and obtain a low-frequency pulse beam period 1 / f L The effective integral value data set in the range is used to obtain the effective integral minimum value S from the effective integral value data set. H，MIN and the effective integral maximum value S H，MAX .

[0144] A2 includes:

[0145] The low-frequency pulse beam period 1 / f is counted using a histogram L Each high frequency cycle within 1 / fH The sampling data distribution includes:

[0146] The beam current interval value i (mA) of the distribution histogram is used as the accuracy value for solving the beam current parameters. Since the pulse beam current waveform is a square wave, the beam current I x (I b or I p ) or I xp (I bp or I pp ) is a beam current value I 1 , must be located in the interval with the largest number of sample values ​​in the distribution histogram, and the middle value of the interval with the largest number of samples is used to approximate I x (I b or I p ) or I xp (I bp or I pp ), the beam current value I 1 For I x or I xp one of the.

[0147] Histogram structures, such as Figure 7 As shown in the figure, different amounts of data are distributed in different intervals. The interval with the largest amount of data is used, and a value in this interval is taken as the beam current value I 1 .

[0148] A3 includes:

[0149] According to the effective integral maximum value S H，MAX With the effective integral maximum value S H，MAX The corresponding distribution histogram is solved to obtain the beam current value I 1 , combined with high-frequency pulse parameters, high-frequency pulse parameters include duty cycle δ H and frequency f H , and then calculate the first set of beam parameter estimates, including the peak current estimate I p And the peak-to-peak current estimate I pp ;

[0150] At this time, it is assumed that the beam current value I 1 For I p , then I pp =(S H，MAX f H -I 1 (1-δ H )) / δ H , judge according to the size of the two values, and finally decide I p or I pp ;

[0151] If (S H，MAXf H -I 1 (1-δ H )) / δ H Greater than or equal to I 1 , then the assumption holds:

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

[0153] If (S H，MAX f H -I 1 (1-δ H )) / δ H Less than I 1 , then the assumption does not hold:

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

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

[0156] According to the effective integral minimum value S H，MIN and the effective integral minimum value S H，MIN The corresponding distribution histogram is solved to obtain the value I 1 , combined with the high-frequency pulse rectification cycle parameters, the high-frequency pulse parameters include the duty cycle δ H and frequency f H , and then calculate the second set of beam parameter estimates, including the reference current estimate I b and the estimated base stack peak current I bp ;

[0157] At this time, it is assumed that the value I 1 For I b , then I bp =(S H，MIN f H -I 1 (1-δ H )) / δ H , judge according to the size of the two values, and finally decide I b or Ipp ;

[0158] If (S H，MIN f H -I 1 (1-δ H )) / δ H Greater than or equal to I 1 , then the assumption holds:

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

[0160] If (S H，MIN f H -I 1 (1-δ H )) / δ H Less than I 1 , then the assumption does not hold:

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

[0162] After the above calculation, we get a low-frequency pulse beam period 1 / f L The estimated beam parameters within the b , estimated value of base stack peak current I bp , peak current estimated value I p And the peak-to-peak current estimate I pp .

[0163] A5 includes:

[0164] Based on the estimated beam parameter value, calculate the third integral S of the estimated beam parameter value C , calculate the third integral value S C and the second integral value S L The first deviation rate 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, indicating that the beam waveform is in a stable state, and the obtained 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 , indicating that the estimated value is wrong, and recalculation starts from A1.

[0165] The pulse beam parameters are set at t=0. When t>t1, that is, after the first set time period, a second PID operation is performed based on the effective beam parameter estimation value, and a voltage control signal is output to control the output of the first low voltage, the second low voltage and the third high voltage. Feedback adjustment is performed on the base peak parameter value in the high-frequency composite pulse beam waveform. This is the outer loop of the beam feedback, also called beam fine-tuning.

[0166] During the fine adjustment 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 adjustment result more accurate.

[0167] The high-frequency composite pulse electron beam welding beam feedback control method of this embodiment performs an integration operation on the high-frequency pulse sampling data, ignoring the influence of factors such as timing and delay on the beam parameters, and selecting the maximum and minimum values ​​of the integration operation result according to the result of the integration operation, obtaining a numerical value approximating a beam parameter estimation value in the data interval with the largest amount of data in the statistical data distribution histogram corresponding to the maximum value of the integration operation result, and combining it with the high-frequency pulse parameters to calculate and obtain the first group of beam parameter estimation values, and similarly, obtaining a numerical value approximating a beam parameter estimation value in the data interval with the largest amount of data in the statistical data distribution histogram corresponding to the minimum value of the integration operation result, and combining it with the high-frequency pulse parameters to calculate and obtain the first group of beam parameter estimation values. The second set of beam parameter estimates are calculated, thereby calculating the estimated values ​​of all beam currents in one operation cycle, performing integration operation on the estimated values ​​of the beam current to obtain a third integral, performing integration operation on the sampled data to obtain a second integral, calculating the deviation rate between the third integral and the second integral, and when the deviation rate is less than the deviation rate threshold, the estimated value is considered valid. Through the above operations, the influence of delay, interference and other factors of the real-time sampling data on the feedback is eliminated, the accuracy of the data used for feedback calculation is guaranteed, the accuracy of the feedback adjustment of the first low voltage and the second low voltage is guaranteed, and the beam-bias voltage comparison table is updated through the effective estimated value, thereby further improving the accuracy of the bias voltage control.

[0168] This application designs a method for calculating the waveform parameters of high-frequency composite pulse beams based on the integral value of the sampled data in the high-frequency and low-frequency pulse cycles and the distribution of the sampled data in the high-frequency pulse cycle. When the pulse beam output is relatively stable, the base peak parameter values ​​in the conventional pulse beam waveform and the high-frequency composite pulse beam waveform can be well solved for feedback control, thereby improving the accuracy of feedback control. The problem of large deviation between the actual output beam parameters and the set values ​​during high-frequency pulses is solved.

[0169] It should be understood that the expressions "mechanism", "device", "component" and the like used in this application are only a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the word can be replaced by other expressions.

[0170] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for realizing the present invention, and in practical applications, the technical features of the above-mentioned embodiments can be arbitrarily combined. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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 in form and details without departing from the spirit and scope of the present invention.

Claims

1. A high-frequency composite pulse electron beam welding beam feedback control circuit, characterized in that: include: A sampling unit, a data processing unit and a power supply unit, wherein the data processing unit is connected to the sampling unit and the power supply unit respectively; the sampling unit is used to collect the current signal of the electron beam flow and the voltage signal of the power supply unit, and respectively amplifies the current signal and the voltage signal 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, and the voltage control signal 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, and the power supply unit outputs high voltage after inverting and converting the low-voltage output, and the output high voltage of the power supply unit is used to control the electron beam flow.

2. The high-frequency composite pulse electron beam welding beam feedback control circuit according to claim 1, characterized in that: The sampling unit comprises: a current sampling module and a voltage sampling module. The current sampling module is used to collect the current signal of the electron beam flow, and the voltage sampling module is used to collect the voltage signal of the power supply unit.

3. The high-frequency composite pulse electron beam welding beam feedback control circuit according to claim 2, characterized in that: The current sampling module includes: a sampling circuit, an amplifying circuit, and a voltage-current conversion circuit connected in sequence. The sampling circuit is used to collect the current signal of the electron beam to obtain a collected voltage signal. The amplifying circuit is used to amplify the collected voltage signal to obtain an amplified voltage signal. The voltage-current conversion circuit is used to convert the amplified voltage signal into a sampling current signal and transmit it to a data processing unit.

4. The high-frequency composite pulse electron beam welding beam feedback control circuit according to claim 3, characterized in that: The sampling circuit comprises: a sampling subcircuit and a voltage dividing subcircuit connected in parallel, the sampling subcircuit is used to collect the current signal of the electron beam acting on the workpiece, and the voltage dividing subcircuit is used to divide and filter the current signal of the sampled electron beam to obtain a collected voltage signal.

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

6. The high-frequency composite pulse electron beam welding beam feedback control circuit according to claim 5, characterized in that: The first amplifying sub-circuit includes a high-speed instrumentation amplifier; the second amplifying sub-circuit includes a high-speed isolation amplifier; and the third amplifying sub-circuit includes a differential amplifier.

7. The high-frequency composite pulse electron beam welding beam feedback control circuit according to claim 3, characterized in that: The voltage-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 amplified result into a sampling current signal.

8. The high-frequency composite pulse electron beam welding beam feedback control circuit according to claim 1, characterized in that: The data processing unit includes: a current-voltage conversion circuit, an analog-to-digital conversion circuit and a control circuit connected in sequence, the current-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 sampling current signal, and the control circuit is used to perform calculations based on the digital sampling current signal and the sampling voltage signal of the power supply unit to obtain a voltage control signal and transmit it to the power supply unit.

9. The high-frequency composite pulse electron beam welding beam feedback control circuit according to claim 1, characterized in that: The power supply unit comprises: a first high-voltage generating circuit and a second high-voltage generating circuit, wherein an output end of the first high-voltage generating circuit is connected to an output end of the second high-voltage generating circuit, another output end of the first high-voltage generating circuit and another output end of the second high-voltage generating circuit are respectively used as output ends of the power supply unit, the first high-voltage generating circuit is respectively connected to a sampling unit and a data processing unit, the second high-voltage generating circuit is respectively connected to the sampling unit and the data processing unit, the sampling unit samples a first low-voltage signal of the first high-voltage generating circuit and a second low-voltage signal of the second high-voltage generating circuit respectively, the data processing unit controls the output of the first high-voltage generating circuit and the output of the second high-voltage generating circuit according to the first low-voltage signal sampling signal, the second low-voltage signal sampling signal and the sampling current signal, and the output of the first high-voltage generating circuit and the output of the second high-voltage generating circuit are superimposed in series as the output of the power supply unit.

10. The high-frequency composite pulse electron beam welding beam feedback control circuit according to claim 9, 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 direct current, the inverter circuit is used to convert the low-voltage direct current into a first alternating current, the isolation transformer is used to convert the first alternating current into a second alternating current, and the high-frequency pulse bias power supply high-voltage circuit is used to output high voltage according to the second alternating current.

11. A high-frequency composite pulse electron beam welding beam feedback control method, characterized in that: Applicable to the high-frequency composite pulse electron beam welding beam feedback control circuit according to any one of claims 1 to 10, the method comprising: The sampling unit is used to collect the current signal of the electron beam flow and the low voltage signal of the power supply unit, and the sampled current signal and the sampled voltage signal are amplified to obtain sampling data, wherein the sampling data includes the sampled current signal of the electron beam flow and the sampled voltage signal of the power supply unit; Using a data processing unit, setting pulse electron beam parameters, outputting a voltage control signal according to a beam current-bias voltage comparison table, and controlling 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 high voltage after inverting the low voltage output; and The electron beam current is controlled based on the output high voltage of the power supply unit.

12. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 11, characterized in that: The processing operation on the sampled data specifically includes: Statistical sampling data distribution interval; Calculating a second integral value of the sampled data within one operation cycle; In one operation cycle, the first integral value of the sampling data of each high-frequency pulse beam cycle is calculated to obtain an effective integral value, and the maximum effective integral value and the minimum effective integral value in one operation cycle are obtained; The beam parameter estimation value is calculated based on the effective integral maximum value, the data distribution interval corresponding to the effective integral maximum value, the effective integral minimum value, the data distribution interval corresponding to the effective integral minimum value, and the high-frequency pulse parameters; The third integral of the beam parameter estimation value is calculated. When the first deviation rate between the third integral and the second integral meets the requirement, the beam parameter estimation value is valid. The valid beam parameter estimation value is used for calculation, and a voltage control signal is output to the power supply unit for adjusting the low voltage output of the power supply unit.

13. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 12, characterized in that: The processing operation of the sampled data by the data processing unit also includes: A second set time period is set, and a second deviation rate between an estimated value of a beam parameter and a set value within the second set time period is calculated. When the second deviation rate is less than a second deviation rate threshold, the beam current-bias voltage comparison table is updated.

14. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 12, characterized in that: The calculating of the maximum effective integral value and the minimum effective integral value within one operation cycle includes: In one operation cycle, a first integral value of the sampling data of each high-frequency pulse beam cycle is calculated; When the change rate between the first integral value of the current cycle and the first integral value of the previous cycle is less than the change rate threshold, marking the first integral value of the current cycle as a valid integral value; From a data set of effective integral values ​​in an operation cycle, obtain an effective integral maximum value and an effective integral minimum value.

15. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 12, characterized in that: The calculating of the estimated value of the beam parameter comprises: A beam current value is obtained from the data distribution interval corresponding to the effective integral maximum value. Combining the effective integral maximum value and the set beam current parameters, the first set of beam current parameter estimates are calculated, including the peak current estimate I p , peak-to-peak current estimation value I pp ; A beam current value is obtained from the data distribution interval corresponding to the effective integral minimum value. Combining the effective integral minimum value and the set beam current parameters, the second set of beam current parameter estimates are calculated, including the base current estimate I b , estimated value of base stack peak current I bp .

16. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 15, characterized in that: The step of obtaining a beam current value from the data distribution interval includes: The sampling data is statistically analyzed using a distribution histogram, and a value is taken from the interval with the largest amount of data in the distribution histogram of the sampling data as a beam current value.

17. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 16, characterized in that: The peak-to-peak current estimation value I is calculated pp ,include: From the interval with the largest number of sampled values ​​in the distribution histogram of the sampled data corresponding to the maximum effective integral value, a value is obtained as a beam current value I1. Assume that the beam current value I1 is the peak current estimated value I p , then the peak-to-peak current estimate value I is calculated by the following formula pp : I pp =(S H，MAX f H -I1(1-δ H )) / δ H ; Estimated value I based on the peak current p And the peak-to-peak current estimate I pp The two values ​​are judged and the peak current estimation value I is finally determined. p Or the peak-to-peak current estimate I pp ; If (S H，MAX f H -I1(1-δ H )) / δ H If it is greater than or equal to I1, then the following assumptions hold: I p =I1、I pp =(S H，MAX f H -I1(1-δ H )) / δ H ; If (S H，MAX f H -I1(1-δ H )) / δ H If it is less than I1, the following assumptions do not hold: I pp =I1、I p =(S H，MAX f H -I1δ H ) / (1-δ H ); In the formula, S H，MA represents the maximum effective integral value, f H represents the high-frequency pulse frequency, δ H Indicates the duty cycle of high-frequency pulses.

18. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 16, characterized in that: The calculation base stack peak current estimation value I bp ,include: From the interval with the largest number of sampled values ​​in the distribution histogram of the sampled data corresponding to the minimum effective integral value, a value is obtained as a beam current value I1. Assume that the beam current value I1 is the reference current estimated value I b , then the base stack peak current estimate I is calculated by the following formula bp : I bp =(S H，MIN f H -I1(1-δ H )) / δ H , Estimated value I based on reference current b and the estimated base stack peak current I bp The two values ​​are judged and the reference current estimation value I is finally determined. b Or the estimated base stack peak current I bp ; If (S H，MIN f H -I1(1-δ H )) / δ H If it is greater than or equal to I1, then the following assumptions hold: I b = I1, I bp = (S H，MIN f H - I1(1 - δ H )) / δ H ; If (S H，MIN f H - I1(1 - δ H )) / δ H is less than I1, then The following assumptions do not hold: I bp =I1,I b =(S H，MIN f H -I1δ H ) / (1-δ H );where S H，MIN represents the effective minimum integral value, f H represents the high-frequency pulse frequency, δ H Indicates the duty cycle of high-frequency pulses.

19. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 12, characterized in that: When the first deviation rate between the third integral and the second integral meets the requirement, the beam parameter estimation value is valid, including: Calculating a third integral of the beam parameter estimation value according to the first group of beam parameter estimation values ​​and the second group of beam parameter estimation values, and calculating a 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, the first integral value of the sampling data of each high-frequency pulse beam period, the first group of beam parameter estimation values, the second group of beam parameter estimation values ​​and the third integral of the beam parameter estimation values ​​are calculated again within one operation cycle to obtain valid beam parameter estimation values.

20. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 12, characterized in that: The low-voltage output includes: a first low-voltage output and a second low-voltage output; The processing of the sampled data to adjust the voltage control signal and adjust the low voltage output of the power supply unit includes: The first low voltage and the second low voltage are sampled, and calculation is performed according to the sampled first low voltage and the second low voltage to output a voltage control signal to adjust the output of the first low voltage and the second low voltage respectively.

21. The high-frequency composite pulse electron beam welding beam feedback control method according to claim 12 or 13, characterized in that: The data processing unit is used to process the sampled data, and further includes: A first set time period is set, and after the first set time period has passed, a valid beam parameter estimation value is used to perform calculations, output a voltage control signal, and control the low voltage output.

22. A high-frequency composite pulse electron beam welding beam feedback control system, characterized in that: include: According to the high-frequency composite pulse electron beam welding beam feedback control circuit and electron beam generating device as described in any one of claims 1-10, 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 a 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 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 sampling signal of the power supply unit, and outputs a voltage control signal, and 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 high voltage after inverting and converting the low-voltage output, and the output high voltage of the power supply unit is transmitted to the electron beam generating device, and the electron beam generating device controls the electron beam according to the output high voltage of the power supply unit.

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