Detection and collection system and method for electron gun discharge signal

Abstract

The present invention discloses a detection and collection system and method for the discharge signal of an electron gun, which is composed of a Rogowski coil, a signal conditioning unit, a high-speed sampling unit and an industrial control computer. The Rogowski coil is arranged in the cooling cavity of the electron gun and sleeved on the high-voltage cable head; the output end of the Rogowski coil is led out of the electron gun through a signal cable head arranged on the metal wall of the cooling cavity of the electron gun and connected to the input end of the signal conditioning unit; the output end of the signal conditioning unit is connected to the input end of the industrial control computer through the high-speed sampling unit. The Rogowski coil is used as a detection element to detect the dynamic current of the electron gun discharge, realizing non-contact high-precision on-line detection, and by analyzing the electron gun discharge signal sampled by the Rogowski coil, an electron gun discharge signal database is established, so as to facilitate the subsequent analysis and summary of the electron gun discharge process and accelerate the development of devices for suppressing the harmfulness of the electron gun discharge.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-voltage equipment discharge monitoring, and particularly relates to a detection and collection system and method for electron gun discharge signals. Background Art

[0002] Research on various high-voltage discharges in the power system is very active. By studying partial discharges, the severity of the development of insulation defects can be diagnosed. According to the characteristics of partial discharge signals, the insulation defects and fault types inside power equipment can be effectively reflected, providing technical support for maintenance strategies. Therefore, partial discharge measurement is widely used as one of the main means to detect the insulation state of power equipment both at home and abroad, and the partial discharge characteristics are used as the main indicators for monitoring the quality of the insulation state.

[0003] The electron gun, a key component in electron beam processing equipment, is a DC high-voltage device. Discharge phenomena often occur during the operation of the electron gun, which has an adverse impact on the reliable operation of the equipment. Due to the multi-electrode complex structure of the electron gun, it operates in a dynamic high-vacuum state, and in addition, there is an electron beam passing through the anode and cathode of the electron gun. Therefore, the mechanism characteristics of electron gun discharge are essentially different from those of general power equipment discharge.

[0004] At present, there are very few publicly reported systematic research results on the discharge characteristics of electron guns. When studying electron gun discharge, the research and analysis methods of high-voltage discharge in the power system field can be borrowed, but the results are not comparable. The reasons are as follows: The insulating medium of the electron gun has both solid and dynamic vacuum. Most particularly, this dynamic vacuum serves both as the high-voltage insulating medium between the anode and cathode and as the electron beam flight channel; the dynamic vacuum has both changes in vacuum degree and changes in interfering gas components. To study the discharge characteristics of the electron gun, first, the discharge signals of the electron gun need to be sampled. Simply applying a DC high-voltage power supply to the electron gun cannot reflect the operating conditions of the electron gun discharge. The discharge signals of the electron gun need to be detected online during the actual operation process. Summary of the Invention

[0005] The problem to be solved by the present invention is the online detection of electron gun discharge signals, and a detection and collection system and method for electron gun discharge signals are provided.

[0006] To solve the above problems, the present invention is realized through the following technical solutions:

[0007] The detection and collection system of the electron gun discharge signal is composed of a Rogowski coil, a signal conditioning unit, a high-speed sampling unit and an industrial computer; the Rogowski coil is arranged in the cooling chamber of the electron gun and is sleeved on the high-voltage cable head; the output end of the Rogowski coil is led out of the electron gun through a signal cable head arranged on the metal wall of the cooling chamber of the electron gun and is connected to the input end of the signal conditioning unit; the output end of the signal conditioning unit is connected to the input end of the industrial computer through the high-speed sampling unit.

[0008] In the above scheme, the Rogowski coil consists of a frame and a coil, the frame is in a ring shape, and the coil is wound around the frame.

[0009] In the above solution, the frame is made of insulating non-magnetic conductive material or made of high-resistance and high-frequency magnetic conductive material.

[0010] In the above scheme, the industrial computer is connected to the central controller of the electron gun.

[0011] The method for detecting and collecting the electron gun discharge signal implemented by the above system comprises the following steps:

[0012] Step 1: The Rogowski coil induces the AC component of the total current passing through the coil into a voltage signal u(t) and transmits it to the signal conditioning unit;

[0013] Step 2: The signal conditioning unit conditions the voltage signal u(t) and outputs a current signal i(t), and then transfers the current signal i(t) to the high-speed sampling unit;

[0014] Step 3, the high-speed sampling unit performs high-speed digital sampling on the current signal i(t) sent by the signal conditioning unit at a fixed period;

[0015] During the sampling process, when the current signal i(t) is at time t s When the current signal i(t) crosses the normal band limit, it is determined that the discharge has started; when the current signal i(t) returns to the normal band limit at time t1, it is determined that the first wave of the discharge has ended; when the current signal i(t) returns to the normal band limit at time t e Return to the normal limited band and at time t e A certain period of time later t The internal current signal i(t) is always maintained within the normal limited band (-I d , I d ) when the fluctuation occurs, the time t e The discharge ends; from time t s To time t e , the high-speed sampling unit takes the sampling data of the current signal i(t) as the effective sampling data of this discharge and transfers it to the industrial computer;

[0016] Step 4: The industrial control computer calculates the discharge signal characteristic data of the current discharge based on the effective sampling data of the current discharge sent by the high-speed sampling unit, and writes the discharge signal characteristic data of the current discharge and the recorded operating condition parameters of the electron gun into the discharge signal database of the industrial control computer;

[0017] The above-mentioned discharge signal characteristic data includes the first-wave duration τ1, the first-wave current flux Q1, the first-wave average current I1, and the first-wave current peak I m1 , the duration τ, the current flux Q, the average current I, the current peak I m , the peak wave sequence W, the oscillation number N, and the current spectrum;

[0018] The above-mentioned operating condition parameters of the electron gun include the accelerating voltage, the electron beam current, the gun chamber vacuum degree, and the working chamber vacuum degree.

[0019] The specific process of the above-mentioned Step 3 is as follows:

[0020] Step 3.1: Initialization: Set the normal band-limiting threshold I d , the end threshold M, and the sampling period T0; at the same time, set the discharge end flag E to 0;

[0021] Step 3.2: The high-speed sampling unit samples the current signal i(t) of the signal conditioning unit at a fixed sampling period T0 to obtain the sampling data D i (t) at the current moment;

[0022] Step 3.3: Determine whether the sampling data D i (t) at the current moment crosses the normal band-limiting (-I d , I d ), that is:

[0023] If it does not cross, that is, D i (t) < I d , then ignore the sampling data D i (t) at the current moment, and go to Step 3.2;

[0024] If it crosses, that is, D i (t) ≥ I d , then take the current sampling moment as the starting moment t s of the current discharge, and store the sampling data D i (t) at the current sampling moment into the storage unit at the address number Γ s of the sampling data storage area of the high-speed sampling unit, and go to Step 3.4;

[0025] Step 3.4: The high-speed sampling unit continues to sample the current signal i(t) of the signal conditioning unit at a fixed sampling period T0, and stores the sampling data D i(t) is stored sequentially in the storage unit of the sampling data storage area of the high-speed sampling unit, and one sampling data D i (t) occupies the storage unit with an address number in the sampling data storage area;

[0026] Step 3.5: Take the absolute value |D i (t)| of the sampling data D i (t) at the current moment and compare it with the normal band-limiting threshold I d :

[0027] If |D i (t)| > I d , then set the discharge end flag E to 0 and go to Step 3.4;

[0028] If |D i (t)| ≤ I d , then first increment the discharge end flag E by 1, and then determine whether the discharge end flag E exceeds the end threshold M:

[0029] If it does not exceed, that is, E ≤ M, then go to Step 3.4;

[0030] If it exceeds, that is, E > M, then go to Step 3.6;

[0031] Step 3.6: Record the sampling data D i (t) at the current sampling moment, that is, the moment when E > M, in the address number Γ e in the sampling data storage area of the high-speed sampling unit, and use the sampling moment of the sampling data D e stored in the storage unit with the address number Γ i (t) - M + 1 as the discharge end moment t e of this discharge;

[0032] Step 3.7: Send the sampling data D s stored in the storage units from the address number Γ e to the address number Γ i (t) - M + 1 as the effective sampling data of this discharge to the industrial control computer, and set the discharge end flag E to 0;

[0033] Step 3.8: The high-speed sampling unit repeats the above Steps 3.2 - 3.7 to collect the effective sampling data of each discharge during the entire working process of the electron gun until the electron gun of the electron gun discharge signal detection and collection system or the electron beam processing equipment stops working.

[0034] The specific process of the above Step 4 is as follows:

[0035] Step 4.1: Initialization: Set the sampling period T0 and the normal band-limiting threshold I d; Meanwhile, set the peak value of the first-wave current I m1 , the peak current I m , the cumulative value of the first-wave current q1, the cumulative value of the absolute current value q, the peak wave sequence W, and the number of oscillations N to 0;

[0036] Step 4.2: The industrial control computer records the operating condition parameters of the electron gun, namely the accelerating voltage, the electron beam current, the vacuum degree of the gun chamber, and the vacuum degree of the working chamber;

[0037] Step 4.3: The industrial control computer sequentially stores the effective sampling data of the current discharge sent by the high-speed sampling unit into the temporary storage units with address numbers X s to X e in the sampling data temporary storage area of the industrial control computer. The effective sampling data stored in the temporary storage unit with address number X is D(X);

[0038] Step 4.4: Starting from the temporary storage unit with the address number X s in the sampling data temporary storage area, sequentially scan the effective sampling data D(X) in the sampling data temporary storage area; at each scan:

[0039] Step 4.4.1: Add the currently scanned effective sampling data D(X) to the current cumulative value of the first-wave current q1 to update the current cumulative value of the first-wave current q1;

[0040] Step 4.4.2: Compare the currently scanned effective sampling data D(X) with the current peak value of the first-wave current I m1 : If D(X) > I m1 , then assign the currently scanned effective sampling data D(X) to the current peak value of the first-wave current I m1 ; otherwise, keep the current peak value of the first-wave current I m1 unchanged;

[0041] Step 4.4.3: Compare the currently scanned sampling data D(X) with the normal band-limiting threshold I d :

[0042] If D(X) > I d , then continue to scan the effective sampling data in the temporary storage unit with the next address number in the sampling data temporary storage area;

[0043] If D(X) ≤ I d , then record the address number X1 of the temporary storage unit where the currently scanned effective sampling data D(X) is stored, and the sampling moment of the effective sampling data D(X1) stored in the storage unit with address number X1 is used as the end moment t1 of the current discharge. After performing the following operations ① - ⑥, go to Step 4.5;

[0044] ① According to the address number X sWith the address number X1, calculate the first-wave duration τ1, that is:

[0045] τ1 = (X1 - X s )T0

[0046] ② According to the current cumulative value of the first-wave current q1, calculate the first-wave current flux Q1, that is:

[0047] Q1 = q1T0

[0048] ③ According to the first-wave current flux Q1 and the first-wave duration τ1, calculate the average value of the first-wave current I1, that is:

[0049]

[0050] ④ Increment the current peak wave sequence W by 1;

[0051] ⑤ Increment the current oscillation count N by 0.5;

[0052] ⑥ Assign the current peak value of the first-wave current I m1 as the current peak value I of this discharge m ;

[0053] Step 4.5. Determine whether the address number X1 has reached the address number X e :

[0054] If not, that is, X1 < X e , then go to Step 4.6;

[0055] If it has reached, that is, X1 = X e , then regard the moment t1 when the first wave ends as the moment t when this discharge ends, regard the first-wave duration τ1 as the duration τ of this discharge, regard the first-wave current flux Q1 as the current flux Q of this discharge, and regard the average value of the first-wave current I1 as the average value of the current I of this discharge, and then go to Step 4.7; e

[0056]

[0056] Step 4.6. Starting from the storage unit with the address number X1 + 1 in the sampling data temporary storage area to the storage unit with the address number X e of the storage unit, sequentially scan the valid sampling data in the sampling data temporary storage area as D(X); in each scan:

[0057] Step 4.6.1. Add the absolute value of the currently scanned valid sampling data D(X) to the current cumulative value of the absolute current value q to update the current cumulative value of the absolute current value q;

[0058] Step 4.6.2. Compare the absolute value of the currently scanned valid sampling data D(X) with the current current peak value I m : If |D(X)| > I m, assign the absolute value of the currently scanned valid sampling data D(X) to the current current peak value I m ; otherwise, keep the current current peak value I m unchanged;

[0059] Step 4.6.3: Compare the absolute value of the currently scanned valid sampling data D(X) and the absolute value of the previously scanned valid sampling data D(X - 1) with the normal band-limiting threshold I d respectively: If |D(X)| ≤ I d and |D(X - 1)| > I d , then increase the current oscillation count N by 0.5; otherwise, keep the current oscillation count N unchanged;

[0060] Step 4.6.4: Determine whether the storage unit address number X of the currently scanned valid sampling data D(X) has reached the address number X e :

[0061] If not, that is, X < X e , then continue to scan the valid sampling data in the storage unit at the next address number in the sampling data storage area;

[0062] If it has reached, that is, X = X e , then after performing the following operations ① - ③, go to Step 4.7;

[0063] ① According to the address number X s and the address number X e , calculate the duration τ of this discharge, that is:

[0064] τ = (X e - X s )T0

[0065] ② According to the first-wave current flux Q1 and the cumulative value q of the current absolute value, calculate the current flux Q, that is:

[0066] Q = Q1 + qT0

[0067] ③ According to the current flux Q and the duration τ, calculate the average current I, that is:

[0068]

[0069] Step 4.7: Perform discrete Fourier transform on the valid sampling data D(X) stored in the storage units of the sampling data storage area from the address number X s to the address number X e to obtain the current spectrum of this discharge;

[0070] Step 4.8: Write the operating condition parameters of the above electron gun and the discharge signal characteristic data of this discharge into the discharge signal database; the discharge signal characteristic data includes the first wave duration τ1, the first wave current flux Q1, the first wave average current I1, and the first wave current peak I m1 , the duration τ, the current flux Q, the average current I, the current peak I m , the peak wave sequence W, the oscillation times N, and the current spectrum;

[0071] Step 4.9: The industrial control computer repeats the above 4.2 - 4.8 to obtain the operating condition parameters of the electron gun and the discharge signal characteristic data of each discharge of the electron gun during the entire working process until the detection and collection system of the electron gun discharge signal or the electron gun of the electron beam processing equipment stops working.

[0072] Compared with the prior art, the present invention has the following characteristics:

[0073] 1. The high - frequency response of the Rogowski coil covers the discharge signal spectrum of the electron gun. Using the Rogowski coil as the detection element to detect the dynamic current of the electron gun discharge realizes non - contact detection and solves the insulation problem between the detection circuit and the high - voltage potential.

[0074] 2. During normal operation, the electron beam current changes relatively smoothly, and the current signal of the Rogowski coil is small. Once a discharge phenomenon occurs in the electron gun, the current passing through the Rogowski coil changes sharply, and the current signal of the Rogowski coil is large, making it easy to identify the occurrence of the discharge.

[0075] 3. The installation method of the Rogowski coil can accurately identify the electron gun current signal. Since the high - voltage power supply delivered to the high - voltage end of the electron gun through the high - voltage cable includes the filament, bombardment, and bias power supplies, and the combined current of these three power supplies acting on the Rogowski coil is zero, the output current signal of the Rogowski coil does not contain the information of these three power supply currents. The Rogowski coil only detects the electron beam current of the electron gun.

[0076] 4. The Rogowski coil is installed at the electron gun end instead of the conventional high - voltage power supply generating end, eliminating the interference of the parasitic parameters of the high - voltage cable on the measurement of the electron gun discharge signal and improving the accuracy of the electron gun discharge signal detection.

[0077] 5. The system can achieve online continuous detection. The high - speed sampling unit only records the data during the occurrence process of the discharge phenomenon, which not only saves memory but also reduces the data transfer and processing volume, improving the data acquisition efficiency and data processing real - time performance of the system.

[0078] 6. The system conducts in-depth research, comprehensive analysis, and induction on the sampled electron gun discharge signals to establish an electron gun discharge signal database; explores and optimizes the electron gun structure and operating conditions based on the electron gun discharge signal database to eliminate or reduce the discharge probability; explores the route for detecting pre-discharge precursor signals from the discharge signals and develops a device for quickly suppressing the harmfulness of electron gun discharges. Description of the Drawings

[0079] Figure 1 It is a schematic diagram of the electron gun discharge signal collection system;

[0080] Figure 2 is Figure 1 the structural diagram of the Rogowski coil in

[0081] Figure 3 It is a schematic diagram of the electron gun current signal waveform;

[0082] Markings in the figure: 1. Industrial control computer; 2. High-speed sampling unit; 3. Signal conditioning unit; 4. Rogowski coil; 41. Skeleton; 42. Coil; 5. Electron gun; 51. Vacuum chamber; 52. Insulator; 53. Introducing electrode; 54. Cooling chamber; 55. High-voltage cable head, 56. High-voltage cable conductor; 57. Signal cable head. Detailed Implementation Manner

[0083] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the following further elaborates on the present invention in detail with reference to specific examples and the accompanying drawings.

[0084] Refer to Figure 1 , a detection and collection system for electron gun 5 discharge signals, which consists of a Rogowski coil 4, a signal conditioning unit 3, a high-speed sampling unit 2, and an industrial control computer 1. The Rogowski coil 4 is arranged in the cooling chamber 54 of the electron gun 5 and sleeved on the high-voltage cable head 55; the output end of the Rogowski coil 4 is led out of the electron gun 5 through the signal cable head 57 arranged on the metal wall of the cooling chamber 54 of the electron gun 5 and connected to the input end of the signal conditioning unit 3; the output end of the signal conditioning unit 3 is connected to the input end of the industrial control computer 1 through the high-speed sampling unit 2.

[0085] The electron gun 5 of the electron beam processing equipment: It consists of a vacuum chamber 51 and a cooling chamber 54, and the vacuum chamber 51 and the cooling chamber 54 are isolated by an insulator 52 in the middle. An electron source, an electrostatic lens, and a magnetic lens are installed in the vacuum chamber 51 to generate a controllable electron beam. The cooling chamber 54 is filled with insulating cooling oil, and the high-voltage cable head 55 and the signal cable head 57 are installed on the metal wall of the cooling chamber 54. One end of the high-voltage cable conductor 56 is connected to the high-voltage power generator, and the other end of the high-voltage cable conductor 56 is connected to the introducing electrode 53 of the electron gun 5 through the high-voltage cable head 55. The Rogowski coil 4 signal is led out through the signal cable head 57.

[0086] Rogowski coil 4: mainly composed of a frame 41 and a coil 42. The frame 41 is made of an insulating non-magnetic material or a high-resistance high-frequency magnetic material. The coil 42 is wound around the frame 41. Figure 2 The Rogowski coil 4 is installed in the cooling chamber 54 of the electron gun 5, the high-voltage cable head 55 directly passes through the middle of the Rogowski coil 4, and all the high-voltage end electrode connection lines of the electron gun 5 pass through the Rogowski coil 4. The working frequency band of the Rogowski coil 4 is ≥300MHz.

[0087] Signal conditioning unit 3: Receives the output current signal of the Rogowski coil 4, filters and removes noise, performs waveform shaping, and amplifies the output current signal of the Rogowski coil 4 to obtain a current signal i(t), wherein the current signal i(t) represents the AC component of the total current value passing through the Rogowski coil 4, and the current signal i(t) reflects the current waveform during the discharge process of the electron gun 5.

[0088] High-speed sampling unit 2: performs high-speed digital sampling of the current signal i(t) of the signal conditioning unit 3, and stores the digital sampling signal in the RAM memory of the high-speed sampling unit 2; the high-speed sampling unit 2 has its own CPU, and after the detection and collection system of the discharge signal of the electron gun 5 is started, the high-speed sampling unit 2 samples the current signal i(t) at a fixed frequency f0 The input signal of the conditioning unit is continuously sampled, the high-speed sampling unit 2 CPU distinguishes the discharge signal from the normal signal, removes the normal signal, and opens up a RAM continuous unit area to store the discharge signal sampling data. After each discharge, the high-speed sampling unit 2 sends the discharge signal sampling data to the industrial computer 1.

[0089] Industrial computer 1: The memory of industrial computer 1 has two data storage areas, namely, sampling data temporary storage area and discharge signal database storage area. The sampling data temporary storage area is a storage area with continuous address numbers. The discharge signal sampling data output by high-speed sampling unit 2 is sent to the sampling data temporary storage area. The discharge signal database storage area is a data storage area prepared for establishing a discharge signal database of the discharge process of electron gun 5. In addition, industrial computer 1 is also connected to the main control machine of electron gun 5 (industrial computer 1 or the main control machine of electron gun 5 concurrently) to record the operating conditions of electron gun 5. After the detection and collection system of discharge signal of electron gun 5 is started, industrial computer 1 collects the working conditions of electron gun 5, performs characteristic analysis and calculation on the discharge signal sampling data in the sampling data temporary storage area, and adds and stores the characteristic data of the analysis and calculation results and the working condition parameters of electron gun 5 into the discharge signal database. The discharge signal database stores the working conditions of electron gun 5 and the discharge current characteristic data of each discharge process under this working condition. The working conditions of electron gun 5 include acceleration voltage, electron beam current, gun chamber vacuum degree and working chamber vacuum degree data. The current characteristic data of each discharge process include the duration of this discharge τ, the first wave duration τ1, the first wave current flux Q1, the first wave current average value I1, the first wave current peak value I m1 , current flux Q, current average value I, current peak value I m , peak wave sequence W, number of oscillations N and current spectrum.

[0090] The detection and collection system of the discharge signal of the electron gun 5 works simultaneously with the electron gun 5 of the electron beam processing equipment, and uses the current signal i(t) output by the signal conditioning unit 3 to identify the occurrence of the discharge phenomenon of the electron gun 5, that is, when the electron gun 5 is in a normal state, the current signal i(t) output by the signal conditioning unit 3 fluctuates within a normal limited band that is very narrow near the value 0. When the current signal i(t) output by the signal conditioning unit 3 exceeds the normal limited band, that is, |i(t)|≥I d , the normal band limit is represented by the open area (-I d , I d ). When the current signal i(t) output by the signal conditioning unit 3 enters the normal limited band, that is, |i(t)|≤I d , the normal limited band is represented by a closed area [-I d , I d ]. During the operation of the electron gun 5, when the current signal i(t) output by the signal conditioning unit 3 crosses the normal limit band (-I d , I d ), that is, i(t)≥I d When it is judged that discharge occurs, then at i(t)=I d The time t is defined as the starting time t of this discharge s. At the initial stage of the discharge of the electron gun 5, the current signal i(t) output by the signal conditioning unit 3 is positive. However, due to the influence of the discharge circuit parameters, the current signal i(t) output by the signal conditioning unit 3 may experience multiple positive and negative oscillations during the entire discharge process. During the discharge process of the electron gun 5, when the current signal i(t) output by the signal conditioning unit 3 first returns to the normal limited band [-I d , I d , the moment t when i(t) = I d is defined as the end moment t1 of the first wave of this discharge. After that, when the current signal i(t) output by the signal conditioning unit 3 returns to the normal limited band [-I d , I d and fluctuates within the normal limited band (-I d , I d ) for a time period δ t (δ t = MT0), the moment t when |i(t)| = I d is defined as the end moment t e of this discharge.

[0091] During the discharge process of the electron gun 5, the waveform of the signal conditioning unit 3i(t) from the start moment t s to the end moment t e of this discharge is used as the basis for analyzing the discharge current of the electron gun 5.

[0092] Referring to Figure 3 , the current characteristic data of the discharge process of the electron gun 5 are defined as follows:

[0093] The duration τ1 of the first wave is: τ1 = t1 - t s ;

[0094] The current flux Q1 of the first wave is:

[0095] The average current I1 of the first wave is:

[0096] The peak current I m1 of the first wave is: the maximum value of the current signal i(t) within the time period from t s to t1;

[0097] The duration τ is: τ = t e - t s ;

[0098] The current flux Q is:

[0099] The average current I is:

[0100] The peak current Im is: t s -t e the maximum value of the absolute value of the current signal |i(t)| within the time period;

[0101] The peak wave sequence W is: the current peak I m The position of the wave peak that appears is at the Wth wave head;

[0102] The number of oscillations N is: within t s <t ≤ t e the number of oscillations that the current signal i(t) undergoes within the time period; when the current signal i(t) enters the normal band-limited range from outside the normal band-limited range once, it is counted as 0.5 times of the number of oscillations;

[0103] The current spectrum is: for t s -t1 time period of the current signal i(t) is subjected to Fourier transform to convert the time function i(t) into a frequency function, and the main amplitude distribution and the frequency values corresponding to the main amplitude distribution are obtained from the frequency function.

[0104] Based on the above principle, the method for detecting and collecting the discharge signal of the electron gun 5 realized by using the above detection and collection system of the discharge signal of the electron gun 5 mainly includes the following steps:

[0105] Step 1, the Rogowski coil 4 induces the AC component of the total current passing through its coil into a voltage signal u(t) and transfers it to the signal conditioning unit 3.

[0106] Step 2, the signal conditioning unit 3 conditions the voltage signal u(t) and outputs a current signal i(t), and then transfers the current signal i(t) to the high-speed sampling unit 2.

[0107] Step 3, the high-speed sampling unit 2 performs high-speed digital sampling on the current signal i(t) sent by the signal conditioning unit 3 at a fixed period; during the sampling process, when the current signal i(t) crosses the normal band-limited range upward at time t s it is determined that the current discharge starts; when the current signal i(t) returns to the normal band-limited range again at time t1, it is determined that the first wave of this discharge ends; when the current signal i(t) returns to the normal band-limited range at time t e within (t1 may be t e ), and within a certain time period δ e after time t t the current signal i(t) always fluctuates within the normal band-limited range (-I d , I d ), it is determined that time t e is the end of this discharge; from time t s to time t e, the high-speed sampling unit 2 uses the sampling data of the current signal i(t) as the effective sampling data for this discharge and transfers it to the industrial control computer 1. The specific process is as follows:

[0108] Step 3.1, Initialization: Set the normal band-limiting threshold I d , end threshold M, and sampling period T0; at the same time, set the discharge end flag E to 0;

[0109] Step 3.2, The high-speed sampling unit 2 samples the current signal i(t) of the signal conditioning unit 3 at a fixed sampling period T0 to obtain the sampling data D i (t) at the current moment;

[0110] Step 3.3, Determine whether the sampling data D i (t) at the current moment crosses the normal band-limiting (-I d , I d ):

[0111] If D i (t) < I d , it does not cross, then ignore the sampling data D i (t) at the current moment and go to Step 3.2;

[0112] If D i (t) ≥ I d , a crossing occurs, then take the current sampling moment as the starting moment t s of this discharge, and store the sampling data D i (t) at the current sampling moment in the storage unit with the address number Γ s in the sampling data storage area of the high-speed sampling unit 2, and go to Step 3.4;

[0113] Step 3.4, The high-speed sampling unit 2 continues to sample the current signal i(t) of the signal conditioning unit 3 at a fixed sampling period T0 and stores the sampling data D i (t) at the current moment in sequence in the storage units of the sampling data storage area of the high-speed sampling unit 2, and one sampling data D i (t) occupies the storage unit with one address number in the sampling data storage area;

[0114] Step 3.5, Compare the absolute value |D i (t)| of the sampling data D i (t) at the current moment with the normal band-limiting threshold I d :

[0115] If |D i (t)| > I d , then set the discharge end flag E to 0 and go to Step 3.4;

[0116] If |D i (t)| ≤ I d , then first increment the discharge end flag E by 1, and then determine whether the discharge end flag E exceeds the end threshold M: if it does not exceed, i.e., E ≤ M, then go to step 3.4; if it exceeds, i.e., E > M, then go to step 3.6;

[0117] Step 3.6, Record the sampling data D i (t) at the address number Γ in the sampling data storage area of the high-speed sampling unit 2 e , and use the address number Γ e - M + 1 of the storage unit stores the sampling data D i (t) of the sampling time as the time t of the end of the current discharge e ;

[0118] Step 3.7, Transfer the sampling data storage area from the address number Γ s to the address number Γ e - M + 1 of the storage unit stores the sampling data D i (t) as the effective sampling data of the current discharge and send it to the industrial control computer 1, and set the discharge end flag E to 0;

[0119] Step 3.8, The high-speed sampling unit 2 repeats the above steps 3.2 - 3.7 to collect the effective sampling data of each discharge of the electron gun 5 during the entire working process until the detection and collection system of the discharge signal of the electron gun 5 or the electron gun 5 of the electron beam processing equipment stops working.

[0120] Step 4, The industrial control computer 1 calculates the discharge signal characteristic data of the current discharge based on the effective sampling data of the current discharge sent by the high-speed sampling unit 2, and writes the discharge signal characteristic data of the current discharge and the recorded operating condition parameters of the electron gun 5 into the discharge signal database of the industrial control computer 1; the above discharge signal characteristic data includes the first wave duration τ1, the first wave current flux Q1, the first wave current average value I1, the first wave current peak value I m1 , the duration τ, the current flux Q, the current average value I, the current peak value I m , the peak wave sequence W, the oscillation number N and the current spectrum; the above operating condition parameters of the electron gun 5 include the accelerating voltage, the electron beam current, the gun chamber vacuum degree and the working chamber vacuum degree. The specific process is as follows:

[0121] Step 4.1, Initialization: Set the sampling period T0 and the normal band-limited threshold I d ; At the same time, set the first wave current peak value I m1 , the current peak value I m , the first wave current cumulative value q1, the current absolute value cumulative value q, the peak wave sequence W and the oscillation number N to 0;

[0122] Step 4.2: The industrial control computer 1 records the operating condition parameters of the electron gun 5, namely the accelerating voltage, electron beam current, gun chamber vacuum degree, and working chamber vacuum degree.

[0123] Step 4.3: The industrial control computer 1 sequentially stores the valid sampling data of the current discharge sent by the high-speed sampling unit 2 into the storage unit at address number X in the sampling data temporary storage area of the industrial control computer 1. s To address number X e The data in the storage unit, that is, the data in the storage unit at address number Γ of the high-speed sampling unit 2 e is stored in the storage unit at address number X of the industrial control computer 1. s The data in the storage unit at address number Γ of the high-speed sampling unit 2 e is stored in the storage unit at address number X + 1 of the industrial control computer 1. s The data in the storage unit at address number Γ + 1 of the high-speed sampling unit 2 e is stored in the storage unit at address number X + 1 of the industrial control computer 1, …, e The data in the storage unit at address number Γ - M + 1 of the high-speed sampling unit 2 is stored in the storage unit at address number X of the industrial control computer 1. The valid sampling data stored in the storage unit at address number X is D(X).

[0124] Step 4.4: Starting from the storage unit at address number X in the sampling data temporary storage area, sequentially scan the valid sampling data D(X) in the sampling data temporary storage area. At each scan: s The valid sampling data is D(X).

[0125] Step 4.4.1: Add the currently scanned valid sampling data D(X) to the first wave current accumulation value q1 to update the first wave current accumulation value q1. That is, let q1 = D(X) + q1.

[0126] Step 4.4.2: Compare the currently scanned valid sampling data D(X) with the first wave current peak value I m1 : If D(X) > I m1 , then assign the currently scanned valid sampling data D(X) to the first wave current peak value I m1 ; otherwise, keep the first wave current peak value I m1 unchanged.

[0127] Step 4.4.3: Compare the currently scanned sampling data D(X) with the normal band-limited threshold I d :

[0128] If D(X) > I d , then continue to scan the valid sampling data in the storage unit at the next address number in the sampling data temporary storage area.

[0129] If D(X) ≤ I d, record the address number X1 of the temporary storage unit that stores the currently scanned valid sampling data D(X). Take the sampling time of the valid sampling data D(X1) in the temporary storage unit with address number X1 as the ending time t1 of this discharge. After performing the following operations ① - ⑥, go to step 4.5;

[0130] ① Calculate the first-wave duration τ1 based on the address number X s and the address number X1, that is:

[0131] τ1 = (X1 - X s )T0

[0132] ② Calculate the first-wave current flux Q1 based on the first-wave current cumulative value q1, that is:

[0133] Q1 = q1T0

[0134] ③ Calculate the first-wave average current I1 based on the first-wave current flux Q1 and the first-wave duration τ1, that is:

[0135]

[0136] ④ Increment the peak wave sequence W by 1, that is, let W = W + 1;

[0137] ⑤ Increment the oscillation times N by 0.5, that is, let N = N + 0.5;

[0138] ⑥ Assign the first-wave current peak I m1 as the current peak I of this discharge m ;

[0139] Step 4.5, Determine whether the address number X1 has reached the address number X e :

[0140] If not, that is, X1 < X e , then go to step 4.6;

[0141] If it has reached, that is, X1 = X e , then regard the first-wave ending time t1 as the ending time t of this discharge e , regard the first-wave duration τ1 as the duration τ of this discharge, regard the first-wave current flux Q1 as the current flux Q of this discharge, and regard the first-wave average current I1 as the average current I of this discharge; then, go to step 4.7;

[0142] Step 4.6, Starting from the temporary storage unit with the address number X1 + 1 in the sampling data temporary storage area to the temporary storage unit with the address number X e , sequentially scan the valid sampling data in the sampling data temporary storage area as D(X); during each scan:

[0143] Step 4.6.1: Add the absolute value of the currently scanned valid sampling data D(X) to the current absolute current accumulation value q to update the absolute current accumulation value q, i.e., let q = D(X) + q.

[0144] Step 4.6.2: Compare the absolute value of the currently scanned valid sampling data D(X) with the current peak current I m : If |D(X)| > I m , assign the absolute value of the currently scanned valid sampling data D(X) to the current peak current I m ; otherwise, keep the current peak current I m unchanged.

[0145] Step 4.6.3: Compare the absolute value of the currently scanned valid sampling data D(X) and the absolute value of the previously scanned valid sampling data D(X - 1) with the normal band-limiting threshold I d respectively: If |D(X)| ≤ I d and |D(X - 1)| > I d , then increase the oscillation count N by 0.5, i.e., let N = N + 0.5; otherwise, keep the oscillation count N unchanged.

[0146] Step 4.6.4: Determine whether the storage unit address number X of the currently scanned valid sampling data D(X) has reached the address number X e :

[0147] If not, i.e., X < X e , then continue to scan the valid sampling data in the storage unit at the next address number in the sampling data storage area;

[0148] If so, i.e., X = X e , then after performing the following operations ① - ③, go to Step 4.7;

[0149] ① Calculate the discharge duration τ of this time according to the address number X s and the address number X e , i.e.:

[0150] τ = (X e - X s )T0

[0151] ② Calculate the current flux Q according to the first-wave current flux Q1 and the absolute current accumulation value q, i.e.:

[0152] Q = Q1 + qT0

[0153] ③ Calculate the average current I according to the current flux Q and the discharge duration τ, i.e.:

[0154]

[0155] Step 4.7: Perform discrete Fourier transform on the valid sampling data stored in the temporary storage unit of the sampling data temporary storage area from address number X s to address number X e to obtain the current spectrum of this discharge;

[0156] Step 4.8: Write the operating condition parameters of the above electron gun 5 and the discharge signal characteristic data of this discharge into the discharge signal database; the discharge signal characteristic data includes the first wave duration τ1, the first wave current flux Q1, the first wave current average value I1, the first wave current peak value I m1 , the duration τ, the current flux Q, the current average value I, the current peak value I m , the peak wave sequence W, the oscillation number N, and the current spectrum;

[0157] Step 4.9: The industrial control computer 1 repeats the above 4.2 - 4.8 to obtain the operating condition parameters of the electron gun 5 and the discharge signal characteristic data of each discharge of the electron gun 5 during the entire working process until the detection and collection system of the discharge signal of the electron gun 5 or the electron gun 5 of the electron beam processing equipment stops working.

[0158] Step 5: Use the discharge signal database to perform offline analysis, induction, and summary on the current of the electron gun 5, and further establish a discharge fingerprint database of the electron gun 5.

[0159] It should be noted that the focus of the present invention is to realize the detection and collection of the discharge signal of the electron gun 5 during the electron beam processing process, and build a discharge signal database based on this. The subsequent analysis and summary of the discharge process of the electron gun 5 are not the focus of the present invention. In addition, although the embodiments described above of the present invention are illustrative, this is not a limitation of the present invention. Therefore, the present invention is not limited to the above specific embodiments. Without departing from the principle of the present invention, any other embodiments obtained by those skilled in the art under the inspiration of the present invention are regarded as within the protection scope of the present invention.

Claims

1. A detection and collection system for the discharge signal of an electron gun, characterized in that It consists of a Rogowski coil (4), a signal conditioning unit (3), a high-speed sampling unit (2) and an industrial control computer (1); the Rogowski coil (4) consists of a bobbin (41) and a coil (42), the bobbin (41) is in a circular ring shape, and the coil (42) is wound around the bobbin (41); the bobbin (41) is made of an insulating non-magnetic material or a high-resistance high-frequency magnetic material; the Rogowski coil (4) is arranged in the cooling cavity (54) of the electron gun (5) and sleeved on the high-voltage cable head (55); the output end of the Rogowski coil (4) is led out of the electron gun (5) through a signal cable head (57) arranged on the metal wall of the cooling cavity (54) of the electron gun (5) and connected to the input end of the signal conditioning unit (3); the output end of the signal conditioning unit (3) is connected to the input end of the industrial control computer (1) through the high-speed sampling unit (2); the industrial control computer (1) is connected to the central controller of the electron gun (5).

2. Detection and collection method for electron gun discharge signal, the system of which consists of a Rogowski coil (4), a signal conditioning unit (3), a high-speed sampling unit (2) and an industrial control computer (1); the Rogowski coil (4) is arranged in the cooling cavity (54) of the electron gun (5) and sleeved on the high-voltage cable head (55); the output end of the Rogowski coil (4) is led out of the electron gun (5) through a signal cable head (57) arranged on the metal wall of the cooling cavity (54) of the electron gun (5) and connected to the input end of the signal conditioning unit (3); the output end of the signal conditioning unit (3) is connected to the input end of the industrial control computer (1) through the high-speed sampling unit (2), and it is characterized in that, It includes the following steps: Step 1, the Rogowski coil (4) induces the AC component of the total current passing through its coil into a voltage signal u(t) and transfers it to the signal conditioning unit (3); Step 2, the signal conditioning unit (3) conditions the voltage signal u(t) and outputs a current signal i(t), and then transfers the current signal i(t) to the high-speed sampling unit (2); Step 3, the high-speed sampling unit (2) performs high-speed digital sampling on the current signal i(t) sent by the signal conditioning unit (3) at a fixed period; During the sampling process, when the current signal i(t) crosses the normal band limit at time t s , it is determined that the current discharge starts; when the current signal i(t) returns to the normal band limit at time t1, it is determined that the first wave of this discharge ends; when the current signal i(t) returns within the normal band limit at time t e , and within a certain time period δ e after time t, the current signal i(t) always fluctuates within the normal band limit (-I t , I d , I d ), it is determined that time t e is the end of this discharge; from time t s to time t e , the high-speed sampling unit (2) takes the sampling data of the current signal i(t) as the effective sampling data of this discharge and transfers it to the industrial control computer (1); Step 4, the industrial control computer (1) calculates the discharge signal characteristic data of the current discharge based on the effective sampling data of the current discharge sent by the high-speed sampling unit (2), and writes the discharge signal characteristic data of the current discharge and the recorded operating condition parameters of the electron gun (5) into the discharge signal database of the industrial control computer (1); The above discharge signal characteristic data include the first wave duration τ1, the first wave current flux Q1, the first wave average current I1, and the first wave current peak I m1 , the duration τ, the current flux Q, the average current I, and the current peak I m , the peak wave order W, the number of oscillations N, and the current spectrum; The above-mentioned operating condition parameters of the electron gun (5) include the accelerating voltage, electron beam current, gun chamber vacuum degree and working chamber vacuum degree.

3. The method for detecting and collecting the electron gun discharge signal according to claim 2, characterized in that, The specific process of Step 3 is as follows: Step 3.

1. Initialization: Set the normal band-limiting threshold I d , the end threshold M, and the sampling period T0; at the same time, set the discharge end flag E to 0; Step 3.2: The high-speed sampling unit (2) samples the current signal i(t) of the signal conditioning unit (3) at a fixed sampling period T0 to obtain the sampling data D i (t) at the current moment; Step 3.3, determine whether the sampled data D i (t) crosses above the normal band limit (-I d , I d ), that is: If not crossed, i.e., D i (t) < I d , then the sampled data D i (t) at the current moment is ignored, and step 3.2 is proceeded to; If a crossover occurs, i.e., D i (t) ≥ I d , then the current sampling moment is taken as the starting moment t of this discharge s , and the sampling data D i (t) is stored in the storage unit at the address number Γ of the sampling data storage area of the high-speed sampling unit (2) s , and go to step 3.4; Step 3.4: The high-speed sampling unit (2) continues to sample the current signal i(t) of the signal conditioning unit (3) at a fixed sampling period T0, and stores the sampling data D i (t) into the storage unit of the sampling data storage area of the high-speed sampling unit (2) in sequence, and one sampling data D i (t) occupies the storage unit of one address number in the sampling data storage area; Step 3.

5. Compare the absolute value |D i (t)| of the sampling data D i (t) at the current moment with the normal band-limiting threshold I d as follows: If |D i (t)| > I d , then set the discharge end flag E to 0 and go to step 3.4; If |D i (t)| ≤ I d , first increment the discharge end flag E by 1, and then determine whether the discharge end flag E exceeds the end threshold M: If not exceeded, that is, E ≤ M, then go to Step 3.4; If exceeded, that is, E > M, then go to Step 3.6; Step 3.6, record the sampling data D at the current sampling moment, i.e., the moment when E > M i (t), the address number Γ in the sampling data storage area of the high-speed sampling unit (2) e , and use the address number Γ e - The sampling data D stored in the storage unit of M + 1 i (t) as the moment t when this discharge ends e ; Step 3.7: Send the sampling data stored in the storage unit with the storage area of the sampling data from the address number Γ s to the address number Γ e -M + 1 as the effective sampling data D i (t) of this discharge to the industrial control computer (1), and set the discharge end flag E to 0; Step 3.8, the high-speed sampling unit (2) repeats the above Steps 3.2 - 3.7 to collect the effective sampling data of each discharge of the electron gun (5) during the whole working process until the detection and collection system of the electron gun discharge signal or the electron gun (5) of the electron beam processing equipment stops working.

4. The method for detecting and collecting the discharge signal of the electron gun according to claim 2, characterized in that, The specific process of Step 4 is as follows: Step 4.

1. Initialization: Set the sampling period T0 and the normal band-limiting threshold I d ; Meanwhile, set the peak current of the first wave I m1 , the peak current I m , the cumulative value q1 of the first wave current, the cumulative value q of the absolute value of the current, the peak wave sequence W, and the number of oscillations N to 0; Step 4.2, the industrial control computer (1) records the operating condition parameters of the electron gun (5), that is, the accelerating voltage, electron beam current, gun chamber vacuum degree and working chamber vacuum degree; Step 4.3: The industrial control computer (1) sequentially stores the effective sampling data of the current discharge sent by the high-speed sampling unit (2) into the temporary storage units of the sampling data temporary storage area of the industrial control computer (1) with the address number X s to the address number X e in the temporary storage unit, where the effective sampling data stored in the temporary storage unit with the address number X is D(X); Step 4.4: Starting from the temporary storage unit with the address number X in the sampling data temporary storage area s successively scan the valid sampling data in the sampling data temporary storage area as D(X); in each scan: Step 4.4.1, superimpose the currently scanned effective sampling data D(X) on the current first-wave current accumulation value q1 to update the current first-wave current accumulation value q1; Step 4.4.2: Compare the currently scanned valid sampling data D(X) with the current first-wave current peak value I m1 : If D(X) > I m1 , then assign the currently scanned valid sampling data D(X) to the current first-wave current peak value I m1 ; otherwise, keep the current first-wave current peak value I m1 unchanged; Step 4.4.3: Compare the currently scanned sampled data D(X) with the normal band-limiting threshold I d as follows: If D(X) > I d , then continue to scan the valid sampling data in the storage unit at the next address number in the sampling data storage area; If D(X) ≤ I d , record the address number X1 of the temporary storage unit for the valid sampling data D(X) scanned currently. Take the sampling moment of the valid sampling data D(X1) in the storage unit with the address number X1 as the ending moment t1 of this discharge. After performing the following operations ① - ⑥, go to step 4.5; ①According to the address number X s and the address number X1, calculate the first wave duration τ1, that is: τ1 = (X1 - X s )T0 ② According to the current first-wave current accumulation value q1, calculate the first-wave current flux Q1, that is: Q1 = q1T0 ③ According to the first-wave current flux Q1 and the first-wave duration τ1, calculate the first-wave current average value I1, that is: ④ Increment the current peak wave sequence W by 1; ⑤ Increment the current oscillation times N by 0.5; ⑥Assign the current peak primary wave current I m1 to the peak current I of this discharge m ; Step 4.5, determine whether the address number X1 has reached the address number X e : If not achieved, i.e., X1 < X e , then go to step 4.6; If it is reached, i.e., X1 = X e , then the moment t1 when the first wave ends is regarded as the moment t when this discharge ends e , the duration τ1 of the first wave is regarded as the duration τ of this discharge, the current flux Q1 of the first wave is regarded as the current flux Q of this discharge, and the average current I1 of the first wave is regarded as the average current I of this discharge, and then go to step 4.7; Step 4.6: Starting from the storage unit with the address number X1 + 1 in the sampling data temporary storage area to the storage unit with the address number X e , sequentially scan the valid sampling data in the sampling data temporary storage area as D(X); in each scan: Step 4.6.1: Superimpose the absolute value of the currently scanned valid sampling data D(X) onto the current absolute value cumulative value q to update the current absolute value cumulative value q; Step 4.6.2: Compare the absolute value of the currently scanned valid sampling data D(X) with the current peak current I m as follows: If |D(X)| > I m , assign the absolute value of the currently scanned valid sampling data D(X) to the current peak current I m ; otherwise, keep the current peak current I m unchanged; Step 4.6.3: Respectively compare the absolute value of the currently scanned valid sampling data D(X) and the absolute value of the previously scanned valid sampling data D(X - 1) with the normal band-limiting threshold I d as follows: If |D(X)| ≤ I d and |D(X - 1)| > I d , then increase the current oscillation count N by 0.5; otherwise, keep the current oscillation count N unchanged; Step 4.6.4, determine whether the temporary storage unit address number X of the currently scanned valid sampling data D(X) has reached the address number X e : If not reached, i.e., X < X e , then continue to scan the valid sampling data in the storage unit at the next address number in the sampling data storage area; If reached, i.e., X = X e , then after performing the following operations ①-③, go to step 4.7; ①According to the address number X s and the address number X e , calculate the duration τ of this discharge, that is: τ=(X e -X s )T0 ② Calculate the current flux Q based on the first-wave current flux Q1 and the current absolute value cumulative value q, i.e.: Q = Q1 + qT0 ③ Calculate the average current I based on the current flux Q and the duration τ, i.e.: Step 4.7: Perform a discrete Fourier transform on the valid sampling data D(X) stored in the temporary storage units of the sampling data temporary storage area from address number X s to address number X e to obtain the current spectrum of this discharge; Step 4.8, write the operating condition parameters of the above electron gun (5) and the discharge signal characteristic data of this discharge into the discharge signal database; the discharge signal characteristic data includes the first wave duration τ1, the first wave current flux Q1, the first wave current average value I1, and the first wave current peak value I m1 , the duration τ, the current flux Q, the current average value I, and the current peak value I m , the peak wave sequence W, the oscillation times N, and the current spectrum; Step 4.9: The industrial control computer (1) repeats the above steps 4.2 - 4.8 to obtain the operating condition parameters of the electron gun (5) and the discharge signal characteristic data of each discharge during the entire working process of the electron gun (5) until the detection and collection system of the electron gun discharge signal or the electron gun (5) of the electron beam processing equipment stops working.

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