An ultrahigh-voltage electron gun power supply optoelectronic isolation sampling circuit and sampling method

Abstract

The application belongs to the technical field of high-voltage power supply sampling monitoring, and provides an ultrahigh-voltage electron gun power supply photoelectric isolation sampling circuit and a sampling method. In view of the problems of low sampling accuracy, poor surge resistance and difficult maintenance of the existing electron gun power supply under a 150kV floating high-voltage environment, the application adopts three groups of signal processing and isolation channels with the same structure, which correspond to the output of the main high-voltage, the auxiliary high-voltage and the filament in a floating cascade structure. Each channel independently completes sampling and isolation under the corresponding floating potential. The circuit includes a power supply circuit, a sampling connection circuit, a current and voltage sampling base plate with an integrated multi-stage overvoltage clamping network, and a detachable and plug-in sampling processing circuit board, a photoelectric conversion circuit board and an optocoupler signal transmission plugboard. Through photoelectric isolation and modular design, the circuit effectively suppresses the spark surge interference, realizes high-precision and high-reliability sampling, supports plug-and-play, and significantly improves the system maintenance convenience and operation stability.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage power supply sampling and monitoring technology, and relates to an opto-isolated sampling circuit and sampling method for ultra-high voltage electron gun power supply in high-end equipment such as additive manufacturing and electron beam melting. It is particularly suitable for high-precision, high-reliability, and modular sampling under the three floating potentials of the main high voltage, auxiliary high voltage and filament. Background Technology

[0002] In additive manufacturing (such as 3D printing) and electron beam melting, the electron gun needs to continuously supply energy to the target material. This energy comes from the electron gun's high-voltage power supply, which provides crucial process parameters such as accelerating voltage, cathode voltage, and filament current. Especially in additive manufacturing, under the same output power conditions, increasing the accelerating voltage can reduce beam current and beam spot size, thereby significantly improving the forming accuracy of 3D printing. Currently, the accelerating voltage of ultra-high-voltage electron guns has reached 150kV or even higher, placing higher demands on the accurate and stable sampling and monitoring of its high-voltage parameters.

[0003] In traditional electron guns, the high-voltage generator and internal sampling components are typically integrated into the high-voltage tank. However, this design has the following technical drawbacks in practical applications:

[0004] (1) When the high-pressure oil tank malfunctions and needs to be repaired, the internal sampling components often need to be replaced as well. Due to individual differences in the parameters of the sampling components, the subsequent sampling circuit must be readjusted and matched after replacement, which makes it impossible to achieve standardized plug-and-play sampling modules, increasing maintenance complexity and downtime.

[0005] (2) During operation, the electron gun inevitably experiences arcing, with instantaneous discharge current reaching tens to hundreds of amperes. The resulting strong electromagnetic surge directly impacts the sampling circuit inside the high-voltage generator, the electron gun body, and other equipment in the control system. For precision sampling circuits with output voltage typically in the range of 10V, such drastic potential fluctuations can easily lead to permanent damage to the precision electronic components, not only reducing the long-term operational reliability of the entire system but also potentially causing safety hazards.

[0006] (3) In the prior art, the sampling of relevant parameters of the high voltage power supply of the electron gun is generally transmitted using analog voltage signals. However, compared with the high voltage output of the power supply, such weak sampling signals are easily affected by strong electromagnetic interference generated by electron gun firing, power device switching, etc., which leads to distortion and fluctuation of the sampling signal, seriously affecting the sampling accuracy and system control stability.

[0007] (4) Existing sampling circuits are usually divided into multiple parts, such as high-voltage sampling units and low-voltage processing units, which are distributed in different locations of the power supply. This discrete structure has coupling dependence. When one part is damaged due to a fault, it often needs to be replaced as a whole. Not only is the maintenance cost high, but the overall reliability of the system is also difficult to guarantee under long-term operating conditions.

[0008] Therefore, how to effectively improve the sampling accuracy of high-voltage power supply parameters of electron guns, their anti-electromagnetic interference capability, and the modularity and ease of maintenance of the system has become a technical problem that urgently needs to be solved in this field. This is of great significance for promoting scientific research, ensuring production safety, and realizing precision process control. Summary of the Invention

[0009] To address the technical challenges in existing ultra-high voltage electron gun power supply sampling systems, such as the sampling circuit being susceptible to damage from arcing surges, the non-standardized sampling architecture of the three high-voltage signals (main high voltage, auxiliary high voltage, and filament), the need for recalibration after module replacement, and poor anti-interference capability of weak electrical signals, this invention discloses an ultra-high voltage electron gun power supply opto-isolation sampling circuit and sampling method to achieve high reliability, high precision, plug-and-play functionality, and strong electromagnetic compatibility.

[0010] The technical solution for achieving the objective of this invention is as follows: The present invention provides an opto-isolated sampling circuit for an ultra-high voltage electron gun power supply. The circuit includes a power supply circuit, a sampling connection circuit, a current and voltage sampling base plate, and three sets of signal processing and isolation channels with identical structures.

[0011] The power supply circuit provides isolated ±15V and +5V operating power. The sampling connection circuit connects to the main high voltage, auxiliary high voltage, and filament output terminals of the electron gun power supply, and samples each signal. The current and voltage sampling base plate is electrically connected to the sampling connection circuit and integrates a multi-stage overvoltage clamping network composed of varistors and bidirectional diodes.

[0012] Three identical signal processing and isolation channels correspond to the main high voltage, the secondary high voltage, and the filament outputs, respectively. The main high voltage, secondary high voltage, and filament outputs are cascaded in a floating configuration and do not share a common electrical reference point. Each signal processing and isolation channel independently performs sampling and isolation at the floating potential of its corresponding output terminal. The signal processing and isolation channel includes a sampling processing circuit board, a photoelectric conversion circuit board, and an optocoupler signal transmission plug-in board that are connected in sequence. The sampling processing circuit board can be detachably plugged into the corresponding interface of the current and voltage sampling base plate.

[0013] Furthermore, the sampling processing circuit board is used to condition the sampling signal from the current and voltage sampling base plate into a negative polarity analog signal, the photoelectric conversion circuit board is used to convert the negative polarity analog signal into a frequency signal, and the optocoupler signal transmission plug is used to output the frequency signal after electrical isolation through the optocoupler.

[0014] Furthermore, the sampling processing circuit board includes at least two signal processing units with identical structures, which are used to process current sampling signals and voltage sampling signals, respectively. The signal processing unit includes an instrumentation amplifier and a general-purpose operational amplifier. The input terminal of the instrumentation amplifier receives an analog signal from the current and voltage sampling base plate. Its gain is set by an external resistor connected between the first pin and the eighth pin. The output terminal outputs an amplified positive signal. The inverting input terminal of the general-purpose operational amplifier is connected to the output terminal of the instrumentation amplifier, and its output terminal is connected to the inverting input terminal through a feedback resistor. This is used to invert the signal and compensate for its phase, and to output a negative polarity analog signal. The power supply pins of both the instrumentation amplifier and the general-purpose operational amplifier are connected to a low-noise power supply provided by the power supply circuit.

[0015] Furthermore, the photoelectric conversion circuit board includes at least two voltage-to-frequency converters, which are respectively connected to two negative polarity analog signals of the self-sampling processing circuit board; The third pin of each voltage-to-frequency converter is connected to the corresponding input signal, the twelfth and fifth pins are connected to +15V power supply and -15V power supply respectively, the fourteenth pin is grounded through a resistor for bias adjustment, and the eighth pin outputs a positive frequency signal and is coupled and filtered through a capacitor. The output of the voltage-to-frequency converter is connected to a standard connector, and its first and second pins output frequency signals IN1 and IN2, respectively.

[0016] Furthermore, the optocoupler signal transmission board includes at least two high-speed optocouplers, which respectively receive frequency signals IN1 and IN2 output from the photoelectric conversion circuit board via standard connectors; The input terminal of each of the high-speed optocouplers is connected to the corresponding signal pin of a standard connector through a current-limiting resistor, and a filter capacitor for suppressing signal noise is connected in parallel at its input terminal. The high-speed optocoupler outputs an optical signal at its output terminal to achieve electrical isolation.

[0017] Furthermore, the sampling connection circuit includes three sub-sampling circuits, corresponding to the main high voltage, the auxiliary high voltage, and the filament, respectively; In each of the sub-sampling circuits, a first high-resistance voltage divider resistor Rcz1 and a second high-resistance voltage divider resistor Rcz2 are connected between the corresponding main circuit and the local reference ground of the sub-circuit to divide the output voltage of the circuit into a low-voltage signal; a low-resistance sampling resistor Rcz3 is connected in series in the corresponding main circuit of the sub-circuit to convert the output current flowing through the main circuit into a small voltage signal.

[0018] Furthermore, the power supply circuit includes a surge protection and rectification unit, a surge protection and rectification unit, and a filter and voltage regulation network that are connected in sequence. The surge protection and rectification unit includes a rectifier bridge and a TVS diode, which are used to provide reverse connection protection and surge protection for the input power supply. The isolated power conversion unit is used to convert the rectified DC voltage into ±15V isolated output; The filtering and voltage regulation network is connected to the ±15V output terminal and includes a voltage regulator U1, a first capacitor C4, a second capacitor C5 and a third capacitor C6, which are used to provide low-noise power for subsequent signal processing circuits. The surge protection and rectification unit has a surface-mount capacitor C1 and an electrolytic capacitor C0 connected in parallel on the input side to form an input filtering unit.

[0019] Furthermore, the current and voltage sampling base plate is provided with three sets of sub-circuits with the same circuit structure. Each set of sub-circuits is provided with three terminals, which are respectively connected to the voltage output terminal, current output terminal and local reference ground of the corresponding sub-sampling circuit in the sampling connection circuit. A varistor is provided between two adjacent sets of sub-circuits to provide a cross-level surge discharge path between sampling loops at different potentials.

[0020] Furthermore, the power supply circuit, the sampling connection circuit, the current and voltage sampling base plate, the sampling processing circuit board, the photoelectric conversion circuit board, and the optocoupler signal transmission plug are all encapsulated inside the high-voltage insulating oil tank and adopt a modular design with a unified interface, so that any circuit board can be independently disassembled and replaced after damage, without the need for recalibration or adjustment of system parameters, thereby improving equipment maintenance efficiency and operational continuity.

[0021] Another aspect of the present invention provides a photoelectric isolation sampling method for an ultra-high voltage electron gun power supply, the method comprising the following steps: S1: The voltage and current signals of the main high voltage, the auxiliary high voltage, and the filament are initially sampled by the sampling connection circuit to obtain the low-voltage analog signal; S2: The low-voltage analog signal is sent to the current and voltage sampling base plate, and the surge is suppressed by a multi-stage overvoltage clamping network composed of a varistor and a bidirectional diode before being output; S3: The voltage and current signals are amplified, inverted, and phase compensated using the sampling and processing circuit board to generate a negative polarity analog signal; S4: The negative polarity analog signal is linearly converted into a frequency signal proportional to it using a photoelectric conversion circuit board; S5: The frequency signal is converted into an optical signal and electrically isolated output is achieved via the optocoupler signal transmission board; The main high voltage, the auxiliary high voltage, and the filament sampling channels all use the same hardware processing flow, and each channel operates independently under its floating potential.

[0022] The sampling circuit of this invention effectively improves the stability, maintainability, and long-term operational reliability of the system in a 150kV ultra-high voltage environment by setting up a multi-level surge protection network at the front end, adopting three signal processing channels with identical structures, introducing a unified signal conditioning architecture based on AD620 / LM258D, combining AD650JNZ voltage-to-frequency converter and TOTX1952A high-speed optocoupler isolation, and integrating all functional modules into the high-voltage tank and supporting hot-swappable replacement.

[0023] Compared with the prior art, the present invention has at least the following advantages: 1. This invention, based on an opto-isolated sampling architecture and high-precision linear signal conditioning technology, achieves accurate, reliable, and non-invasive acquisition of key parameters such as the main high voltage (up to 150kV), auxiliary high voltage, and filament current of the electron gun. The sampling circuit is connected to the main circuit in parallel, without being inserted into the power path, thus not affecting the stability of the electron gun's high voltage output and avoiding any interference with the electron beam trajectory.

[0024] 2. Both voltage and current measurements adopt the principle of resistance voltage divider / current sampling: a high-resistance voltage divider network (such as Rcz1 / Rcz2) is connected in parallel to the high-voltage end, and a low-resistance sampling resistor (Rcz3) is connected in series in the current loop; the subsequent acquisition module directly measures the low-voltage side signal and, based on the preset voltage divider ratio or sampling resistor value, restores the original high-voltage or high-current value in real time, thereby realizing independent, direct and highly isolated high-voltage parameter measurement.

[0025] 3. This invention adopts a fully modular design, with each functional unit (including sampling connection, signal processing, photoelectric conversion, and transmission plug-in board) having a unified structure and standardized interfaces, supporting independent deployment or overall integration. Any damaged module can be hot-swapped on-site without recalibration or system debugging, significantly improving equipment maintenance efficiency and long-term operational reliability.

[0026] 4. The sampled signal is converted into a frequency signal by the AD650JNZ high-linearity voltage-to-frequency converter, and then transmitted as an optical signal through the TOTX1952A high-speed optocoupler. This solution is not only compatible with various standard optical receivers, but also completely cuts off the ground potential loop, effectively suppresses transient surges and strong electromagnetic interference generated by electron gun firing, and greatly enhances the system's electromagnetic compatibility (EMC) and immunity in complex industrial environments.

[0027] 5. The circuit of the present invention can be used as an independent module to form a complete electron gun high-voltage parameter monitoring system with external sampling software; or it can be directly built into the high-voltage generator of the electron gun high-voltage power supply to perform real-time closed-loop sampling of its output and feed the data back to the control software for power supply performance verification, process parameter control and equipment safety protection, fully supporting the stable operation of high-end application scenarios such as additive manufacturing and electron beam melting. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the opto-isolated sampling circuit of the ultra-high voltage electron gun power supply of the present invention; Figure 2 This is a schematic diagram of the sampling connection circuit; Figure 3 This is a schematic diagram of the power supply circuit; Figure 4 This is the circuit diagram of the current and voltage sampling board; Figure 5 This is a schematic diagram of the current sampling and processing circuit in the sampling and processing circuit board; Figure 6 This is a schematic diagram of the voltage sampling and processing circuit in the sampling and processing circuit board; Figure 7 This is a circuit diagram of a photoelectric conversion circuit board; Figure 8 This is a circuit diagram of an optocoupler signal transmission connector. Figure 9 A flowchart of the opto-isolation sampling method for ultra-high voltage electron gun power supply; The components include: 1. Power supply circuit; 2. Sampling connection circuit; 3. Current and voltage sampling base plate; 4. Sampling processing circuit board; 5. Photoelectric conversion circuit board; and 6. Optocoupler signal transmission plug-in board. Detailed Implementation

[0030] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0031] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features of the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] This invention provides an opto-isolated sampling circuit for an ultra-high voltage electron gun power supply. The electron gun has three high-voltage outputs: main high voltage, auxiliary high voltage, and filament output. See [link to relevant documentation]. Figure 1 As shown, the circuit includes a power supply circuit 1, a sampling connection circuit 2, a current and voltage sampling base plate 3, and three sets of identical signal processing and isolation channels. The sampling connection circuit 2 samples the three high-voltage outputs of the electron gun and outputs them via the current and voltage sampling base plate 3 to the corresponding signal processing and isolation channels for opto-isolation before output. This sampling circuit avoids interference from strong electromagnetic interference such as electron gun arcing on sampling accuracy and signal transmission, ensuring sampling accuracy and consistency of signal standards between modules, and facilitating maintenance.

[0033] Specifically, power supply circuit 1 provides isolated operating power of ±15V and +5V. Sampling connection circuit 2 connects to the main high voltage, auxiliary high voltage, and filament output terminals of the electron gun power supply, and samples each signal. Current and voltage sampling base plate 3 is electrically connected to the sampling connection circuit 2 and integrates a multi-stage overvoltage clamping network composed of varistor and bidirectional diode to suppress transient surges caused by electron gun firing.

[0034] Three identical signal processing and isolation channels correspond to the main high voltage, the secondary high voltage, and the filament outputs, respectively. The main high voltage, secondary high voltage, and filament outputs are cascaded in a floating configuration and do not share a common electrical reference point. Each signal processing and isolation channel independently performs sampling and isolation at the floating potential of its corresponding output terminal. like Figure 1 As shown, the signal processing and isolation channel includes a sampling processing circuit board 4, a photoelectric conversion circuit board 5, and an optocoupler signal transmission plug board 6 connected in sequence. The sampling processing circuit board 4 can be detachably plugged into the corresponding interface of the current and voltage sampling base plate 3.

[0035] In some embodiments, such as Figure 2As shown, the sampling connection circuit 2 includes three sub-sampling circuits, which correspond to the main high voltage, the auxiliary high voltage, and the filament, respectively.

[0036] In each of the sub-sampling circuits, a first high-resistance voltage divider resistor Rcz1 and a second high-resistance voltage divider resistor Rcz2 are connected between the corresponding main circuit and the local reference ground of the sub-circuit to divide the output voltage of the circuit into a low-voltage signal; a low-resistance sampling resistor Rcz3 is connected in series in the corresponding main circuit of the sub-circuit to convert the output current flowing through the main circuit into a small voltage signal.

[0037] More specifically, such as Figure 2 As shown, the electron gun output includes three outputs: main high voltage, secondary high voltage, and filament. The secondary high voltage is suspended above the main high voltage, and the filament is suspended above the secondary high voltage. Rcz1 and Rcz2 are both high-resistance voltage divider resistors with different resistance values. By working together, the 150kV DC high voltage is reduced to about 4V across Rcz2, allowing for direct acquisition of weak voltage signals from points CJ1 and CJ2.

[0038] For example, the main high-voltage current section can be converted from an output current of about 40mA to a voltage signal of about 0.1V across its terminals by connecting a small resistance resistor Rcz3 (0.1R) in series in the output circuit. The voltage signal corresponding to the main high-voltage current can be acquired through two points CJ2 and CJ3.

[0039] The connection principle of the secondary high-voltage and filament output circuits is the same as that of the main high-voltage sampling circuit. The high voltage is divided (stepped down) by Rcf1 and Rcd1, and the output voltage is then acquired through CJ4 / CJ5 and CJ7 / CJ8 at the two ends of Rcf2 and Rcd2, respectively. The current signal is indirectly acquired through CJ5 / CJ6 and CJ8 / CJ9 at the two ends of the sampling resistors Rcf3 and Rcd3.

[0040] In this way, by combining voltage divider resistors and current sampling resistors with different resistance values, sampling signals of different voltage and current levels can be converted into sampling voltage signals of the same standard (main high voltage 0-150kV / auxiliary high voltage 0-1500V / filament 0-50V voltage corresponds to sampling voltage 0-4V, main high voltage 0-40mA / auxiliary high voltage 0-1.5A / filament 0-50A current corresponds to sampling voltage 0-0.1V), which facilitates the standardized design of subsequent sampling circuits.

[0041] In some embodiments, such as Figure 3 As shown, the power supply circuit 1 includes a surge protection and rectification unit, a surge protection and rectification unit, and a filter and voltage regulation network that are connected in sequence.

[0042] The surge protection and rectification unit includes rectifier bridges D1–D4 and TVS diodes SMAJ30CA, used for reverse connection protection and surge protection of the input power supply. The isolated power conversion unit converts the rectified DC voltage to a ±15V isolated output. The filtering and voltage regulation network is connected to the ±15V output terminal and includes a voltage regulator U1, a first capacitor C4, a second capacitor C5, and a third capacitor C6, used to provide low-noise power for subsequent signal processing circuits. A surface-mount capacitor C1 and an electrolytic capacitor C0 are connected in parallel on the input side of the surge protection and rectification unit to form an input filtering unit.

[0043] More specifically, such as Figure 3 As shown, the U0 DC-DC power supply E2415S module can be powered by a half-bridge rectifier (D1-D4) or a direct DC 24V power supply. MOV0 is a varistor to prevent surges from impacting the module's power supply. Electrolytic capacitor C0 and surface-mount capacitor C1 form a capacitor filter circuit, making the module's power supply more stable. The DC-DC power supply E2415S module outputs ±15V and its corresponding 0 potential point 15V0. A controllable precision voltage regulator chip (Qg1) TL431 is used to regulate and calibrate the power supply circuit output, ensuring the final output accuracy of the power supply circuit. Capacitors C2 and C3 also serve to regulate and filter the DC-DC power supply module output. Pin 2 of the U1 DC-DC power supply K7805-500R3 module is connected to 15V0 via GND, pin 1 is connected to 15V+ via input, and outputs +5V, which is grounded through a filter capacitor connected in parallel (C4-C6).

[0044] In some embodiments, such as Figure 4 As shown, the current and voltage sampling base plate 3 is provided with three sets of sub-circuits with the same circuit structure. Each set of sub-circuits is provided with three terminals, which are respectively connected to the voltage output terminal, current output terminal and local reference ground of the corresponding sub-sampling circuit in the sampling connection circuit 2. A varistor MOV4 is provided between two adjacent sets of sub-circuits to provide a cross-level surge discharge path between sampling loops at different potentials.

[0045] More specifically, such as Figure 4 As shown, nodes CJ1-CJ9 in current and voltage sampling base plate 3 can be used as terminals, corresponding to... Figure 3The CJ1-CJ9 sampling points are connected. MOVd4 and MOVd5, as varistors between each pair of the three outputs, provide clamping protection to prevent excessive high voltage and filament voltage from causing component failure in the sampling circuit. D1-D3 provide initial clamping protection for current sampling. R3 / R4, R7 / R8, and R11, as parallel sampling resistors for current acquisition, have a resistance of approximately 0R and serve only for filtering or sampling during later circuit module maintenance. R1 / R2, R5 / R6, and R9 / R10, as parallel sampling resistors for voltage acquisition, supplement the sampling resistors in the power circuit, ensuring a more accurate match between the sampled voltage and the output voltage. Db1-Db6 are bidirectional diodes, which, like the MOVd1-MOVd3 varistors, provide clamping protection to prevent output surges in each output circuit from damaging subsequent sampling circuits.

[0046] In some embodiments, the sampling processing circuit board 4 is used to condition the sampling signal from the current and voltage sampling base plate 3 into a negative polarity analog signal, the photoelectric conversion circuit board 5 is used to convert the negative polarity analog signal into a frequency signal, and the optocoupler signal transmission plug 6 is used to output the frequency signal to the outside after electrically isolating it through an optocoupler.

[0047] In some embodiments, such as Figure 5 and Figure 6 As shown, the sampling processing circuit board 4 includes at least two signal processing units with identical structures, which are used to process current sampling signals and voltage sampling signals, respectively. The signal processing unit includes an instrumentation amplifier and a general-purpose operational amplifier. The instrumentation amplifier, model AD620ANZ, receives analog signals from the current and voltage sampling base plate 3 at its input terminal. Its gain is set by an external resistor connected between the first pin (i.e., pin 1 on the AD620ANZ instrumentation amplifier) ​​and the eighth pin (i.e., pin 8 on the AD620ANZ instrumentation amplifier). The output terminal outputs an amplified positive signal. Furthermore, the input terminal of the instrumentation amplifier is equipped with a bidirectional clamping diode, a current-limiting resistor, and a varistor protection branch to suppress surge overvoltage.

[0048] The general-purpose operational amplifier, model LM258D, has its inverting input connected to the output of the instrumentation amplifier, and its output connected to the inverting input via a feedback resistor. This is used to invert the signal and perform phase compensation, and to output a negative analog signal. The power supply pins of the instrumentation amplifier and the general-purpose operational amplifier are both connected to the low-noise power supply provided by the power supply circuit 1, that is, connected to the filter and voltage regulation network composed of the voltage regulator U1 and capacitors C4, C5 and C6.

[0049] More specifically, such as Figure 5The diagram shows the circuit for current processing. The main high-voltage, auxiliary high-voltage, and filament current acquisition all use the same signal processing module, built on an AD620ANZ operational amplifier. Pins 1 and 8 are connected to gain resistor R18; pins 2 and 3 are connected to the current input and output terminals respectively, protected by bidirectional diodes D12 and D11 connected to 15V0, and grounded through protection resistor L11 and capacitor C11 respectively. R11-R16 in series limit the current. R17 and varistor MOV1 protect the current in the sampling signal processing circuit from excessive current. D13 acts as a clamping protection between the operational amplifier sampling pins. Pins 4 and 7 are connected to ±15V power supply, pin 5 is the standard zero potential point 15V0; pin 6 is connected to the operational amplifier output voltage signal, grounded through sliding resistor RW11 and resistor R111, adjusting the zero potential of the output voltage signal. RW12 and R113 adjust the amplification of the operational amplifier output signal. The output of operational amplifier U11 needs to be connected to dual-channel general-purpose operational amplifier U12 for signal inversion. U12 is a dual-channel general-purpose operational amplifier (OPA) of the LM258D. The output signal of U11 is connected to pin 2 of U12. Pin 1 of U12 outputs a sampling signal, which is connected to pin 6 via R112 to perform phase compensation and inversion operations on the output signal of U11. Pins 4 and 8 of U12 are the component power supply pins, connected to ±15V. Pins 3 and 5 are for positive feedback adjustment, connected to the 15V zero potential point. Finally, the voltage signal inverted by U12 is output as -IN11 through pin 7 of U12.

[0050] like Figure 6 The diagram shows the circuit for voltage processing. The main high voltage, auxiliary high voltage, and filament voltage acquisition all use the same signal processing module, built on the AD620ANZ op-amp. Pins 1 and 8 are connected to gain resistor R28; pins 2 and 3 are connected to the current input and output terminals respectively, protected by bidirectional diodes D22 and D21 to 15V0, and grounded through protection resistor L11 and capacitor C21 respectively. R21-R26 in series limit current. R27 and varistor MOV2 protect the sampling signal processing circuit from excessive current. D23 acts as clamping protection between the op-amp sampling pins. Pins 4 and 7 are connected to ±15V power supply, pin 5 is the standard zero potential point 15V0; pin 6 is connected to the op-amp output voltage signal, grounded through slider RW21 and resistor R211, adjusting the zero potential of the output voltage signal. RW22 and R213 adjust the amplification of the op-amp output signal. The output of op-amp U21 needs to be connected to op-amp U22 for signal inversion. U22 is a dual-channel LM258D general-purpose operational amplifier. The output signal of U21 is connected to pin 2 of U22. Pin 1 of U22 outputs a sampling signal, which is connected to pin 6 via R212 to perform phase compensation and inversion operations on the output signal of U21. Pins 4 and 8 of U22 are the component power supply pins, connected to ±15V. Pins 3 and 5 are for positive feedback adjustment, connected to the 15V zero potential point. Finally, the voltage signal inverted by U22 is output as -IN21 through pin 7 of U22.

[0051] In some embodiments, such as Figure 7 As shown, the current and voltage sampling signals -IN11 and -IN21 processed by the sampling processing circuit board 4 are respectively connected to pin 3 of two voltage-frequency converters U13 and U23 (model AD650JNZ) in the photoelectric conversion circuit board 5.

[0052] Specifically, the third pin (pin 3 on the voltage-frequency converter AD650JNZ) of each voltage-frequency converter is connected to the corresponding input signal, the twelfth pin (pin 12 on the voltage-frequency converter AD650JNZ) and the fifth pin (pin 5 on the voltage-frequency converter AD650JNZ) are connected to the +15V power supply and the -15V power supply respectively, the fourteenth pin (pin 14 on the voltage-frequency converter AD650JNZ) is grounded through a resistor for bias adjustment, and the eighth pin (pin 8 on the voltage-frequency converter AD650JNZ) outputs a positive frequency signal and is coupled and filtered through a capacitor.

[0053] The output terminal of the voltage-frequency converter is connected to a standard connector H1, model FG-PM2.54-2-10P-H8.3. Its first pin (pin 1 on the voltage-frequency converter AD650JNZ) and second pin (pin 2 on the voltage-frequency converter AD650JNZ) output frequency signals IN1 and IN2 respectively.

[0054] In addition, the AD650JNZ contains a monostable trigger for converting analog voltages into constant amplitude pulse frequency signals.

[0055] In some embodiments, such as Figure 8 As shown, the optocoupler signal transmission board 6 includes at least two high-speed optocouplers TX1 and TX2, model TOTX1952A. The input-side withstand voltage of TOTX1952A is not less than 5kV, and the output-side operating voltage is +5V. The current-limiting resistor has a resistance of 10kΩ, and the filter capacitor has a capacitance of 200nF. The high-speed optocouplers TX1 and TX2 respectively receive the frequency signals IN1 and IN2 output from the photoelectric conversion circuit board 5 via the standard connector H1.

[0056] The input terminal of each of the high-speed optocouplers is connected to the corresponding signal pin of the standard connector H1 through a current-limiting resistor, and a filter capacitor for suppressing signal noise is connected in parallel at its input terminal.

[0057] In addition, the standard connector H1 model is FG-PM2.54-2-10P-H8.5, which supports hot-swappable replacement; the output terminal of the high-speed optocoupler outputs an optical signal to achieve electrical isolation.

[0058] In some embodiments, the power supply circuit 1, the sampling connection circuit 2, the current and voltage sampling base plate 3, the sampling processing circuit board 4, the photoelectric conversion circuit board 5, and the optocoupler signal transmission plug-in board 6 are all encapsulated inside the high-voltage insulating oil tank and adopt a modular design with a unified interface, so that any circuit board can be independently disassembled and replaced after damage, without the need for recalibration or adjustment of system parameters, thereby improving equipment maintenance efficiency and operational continuity.

[0059] The sampling circuit of this invention effectively improves the stability, maintainability, and long-term operational reliability of the system in a 150kV ultra-high voltage environment by setting up a multi-level surge protection network at the front end, adopting three signal processing channels with identical structures, introducing a unified signal conditioning architecture based on AD620 / LM258D, combining AD650JNZ voltage-to-frequency converter and TOTX1952A high-speed optocoupler isolation, and integrating all functional modules into the high-voltage tank and supporting hot-swappable replacement.

[0060] This invention also provides an opto-isolated sampling method for an ultra-high voltage electron gun power supply, which can be implemented using the circuit described above, such as... Figure 9 As shown, the method includes the following steps: S1: The voltage and current signals of the main high voltage, the auxiliary high voltage and the filament are initially sampled by the sampling connection circuit 2 to obtain the low voltage analog signal; S2: The low-voltage analog signal is sent to the current and voltage sampling base plate 3, and the surge is suppressed by a multi-stage overvoltage clamping network composed of a varistor and a bidirectional diode before being output. S3: Using the AD620ANZ instrumentation amplifier and LM258D general-purpose operational amplifier in sampling processing circuit board 4, the voltage and current signals are amplified, inverted, and phase compensated to generate a negative polarity analog signal. S4: The negative polarity analog signal is linearly converted into a frequency signal proportional to it by the AD650JNZ voltage-frequency converter in the photoelectric conversion circuit board 5; S5: The frequency signal is converted into an optical signal and electrically isolated output via the TOTX1952A high-speed optocoupler in the optocoupler signal transmission board 6; The main high voltage, the auxiliary high voltage, and the filament sampling channels all use the same hardware processing flow, and each channel operates independently under its floating potential.

[0061] Compared with the prior art, the present invention has at least the following advantages: 1. This invention, based on an opto-isolated sampling architecture and high-precision linear signal conditioning technology, achieves accurate, reliable, and non-invasive acquisition of key parameters such as the main high voltage (up to 150kV), auxiliary high voltage, and filament current of the electron gun. The sampling circuit is connected to the main circuit in parallel, without being inserted into the power path, thus not affecting the stability of the electron gun's high voltage output and avoiding any interference with the electron beam trajectory.

[0062] 2. Both voltage and current measurements adopt the principle of resistance voltage divider / current sampling: a high-resistance voltage divider network (such as Rcz1 / Rcz2) is connected in parallel to the high-voltage end, and a low-resistance sampling resistor (Rcz3) is connected in series in the current loop; the subsequent acquisition module directly measures the low-voltage side signal and, based on the preset voltage divider ratio or sampling resistor value, restores the original high-voltage or high-current value in real time, thereby realizing independent, direct and highly isolated high-voltage parameter measurement.

[0063] 3. This invention adopts a fully modular design, with each functional unit (including sampling connection, signal processing, photoelectric conversion, and transmission plug-in board) having a unified structure and standardized interfaces, supporting independent deployment or overall integration. Any damaged module can be hot-swapped on-site without recalibration or system debugging, significantly improving equipment maintenance efficiency and long-term operational reliability.

[0064] 4. The sampled signal is converted into a frequency signal by the AD650JNZ high-linearity voltage-to-frequency converter, and then transmitted as an optical signal through the TOTX1952A high-speed optocoupler. This solution is not only compatible with various standard optical receivers, but also completely cuts off the ground potential loop, effectively suppresses transient surges and strong electromagnetic interference generated by electron gun firing, and greatly enhances the system's electromagnetic compatibility (EMC) and immunity in complex industrial environments.

[0065] 5. The circuit of the present invention can be used as an independent module to form a complete electron gun high-voltage parameter monitoring system with external sampling software; or it can be directly built into the high-voltage generator of the electron gun high-voltage power supply to perform real-time closed-loop sampling of its output and feed the data back to the control software for power supply performance verification, process parameter control and equipment safety protection, fully supporting the stable operation of high-end application scenarios such as additive manufacturing and electron beam melting.

[0066] Obviously, those skilled in the art should understand that the modules or steps of the above-described embodiments of the present invention can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the embodiments of the present invention are not limited to any particular hardware and software combination.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photoelectric isolation sampling circuit for an ultra-high voltage electron gun power supply, characterized in that, include: Power supply circuit (1) is used to provide isolated working power of ±15V and +5V; The sampling connection circuit (2) connects the main high voltage, auxiliary high voltage and filament output terminals of the electron gun power supply and samples each signal. The current and voltage sampling base plate (3) is electrically connected to the sampling connection circuit (2) and integrates a multi-level overvoltage clamping network composed of a varistor and a bidirectional diode; Three identical signal processing and isolation channels correspond to the main high voltage, the secondary high voltage, and the filament outputs, respectively. The main high voltage, secondary high voltage, and filament outputs are cascaded in a floating configuration and do not share a common electrical reference point. Each signal processing and isolation channel independently performs sampling and isolation at the floating potential of its corresponding output terminal. The signal processing and isolation channel includes a sampling processing circuit board (4), a photoelectric conversion circuit board (5), and an optocoupler signal transmission plug board (6) connected in sequence. The sampling processing circuit board (4) can be detachably plugged into the corresponding interface of the current and voltage sampling base plate (3).

2. The ultra-high voltage electron gun power supply photoelectric isolation sampling circuit according to claim 1, characterized in that, The sampling processing circuit board (4) is used to condition the sampling signal from the current and voltage sampling base plate (3) into a negative polarity analog signal. The photoelectric conversion circuit board (5) is used to convert the negative polarity analog signal into a frequency signal. The optocoupler signal transmission plug (6) is used to output the frequency signal to the outside after electrically isolating it through the optocoupler.

3. The ultra-high voltage electron gun power supply photoelectric isolation sampling circuit according to claim 1 or 2, characterized in that, The sampling processing circuit board (4) includes at least two signal processing units with the same structure, which are used to process current sampling signals and voltage sampling signals respectively; The signal processing unit includes an instrumentation amplifier and a general-purpose operational amplifier. The input terminal of the instrumentation amplifier receives an analog signal from the current and voltage sampling base plate (3). Its gain is set by an external resistor connected between the first pin and the eighth pin. The output terminal outputs an amplified positive signal. The inverting input terminal of the general-purpose operational amplifier is connected to the output terminal of the instrumentation amplifier, and its output terminal is connected to the inverting input terminal through a feedback resistor. This is used to invert the signal and compensate for its phase, and to output a negative polarity analog signal. The power supply pins of the instrumentation amplifier and the general-purpose operational amplifier are both connected to the low-noise power supply provided by the power supply circuit (1).

4. The ultra-high voltage electron gun power supply photoelectric isolation sampling circuit according to claim 1 or 2, characterized in that, The photoelectric conversion circuit board (5) includes at least two voltage-to-frequency converters, which are respectively connected to two negative polarity analog signals of the self-sampling processing circuit board (4); The third pin of each voltage-to-frequency converter is connected to the corresponding input signal, the twelfth and fifth pins are connected to +15V power supply and -15V power supply respectively, the fourteenth pin is grounded through a resistor for bias adjustment, and the eighth pin outputs a positive frequency signal and is coupled and filtered through a capacitor. The output of the voltage-to-frequency converter is connected to a standard connector, and its first and second pins output frequency signals IN1 and IN2, respectively.

5. The ultra-high voltage electron gun power supply photoelectric isolation sampling circuit according to claim 1 or 2, characterized in that, The optocoupler signal transmission board (6) includes at least two high-speed optocouplers, which respectively receive the frequency signal IN1 and frequency signal IN2 output by the optoelectronic conversion circuit board (5) through the standard connector; The input terminal of each of the high-speed optocouplers is connected to the corresponding signal pin of a standard connector through a current-limiting resistor, and a filter capacitor for suppressing signal noise is connected in parallel at its input terminal. The high-speed optocoupler outputs an optical signal at its output terminal to achieve electrical isolation.

6. The ultra-high voltage electron gun power supply photoelectric isolation sampling circuit according to claim 1, characterized in that, The sampling connection circuit (2) includes three sub-sampling circuits, which correspond to the main high voltage, the auxiliary high voltage and the filament respectively; In each of the sub-sampling circuits, a first high-resistance voltage divider resistor Rcz1 and a second high-resistance voltage divider resistor Rcz2 are connected between the corresponding main circuit and the local reference ground of the sub-circuit to divide the output voltage of the circuit into a low-voltage signal; a low-resistance sampling resistor Rcz3 is connected in series in the corresponding main circuit of the sub-circuit to convert the output current flowing through the main circuit into a small voltage signal.

7. The ultra-high voltage electron gun power supply photoelectric isolation sampling circuit according to claim 1, characterized in that, The power supply circuit (1) includes a surge protection and rectification unit, a surge protection and rectification unit and a filter voltage regulator network connected in sequence; The surge protection and rectification unit includes a rectifier bridge and a TVS diode, which are used to provide reverse connection protection and surge protection for the input power supply. The isolated power conversion unit is used to convert the rectified DC voltage into ±15V isolated output; The filtering and voltage regulation network is connected to the ±15V output terminal and includes a voltage regulator U1, a first capacitor C4, a second capacitor C5 and a third capacitor C6, which are used to provide low-noise power for subsequent signal processing circuits. The surge protection and rectification unit has a surface-mount capacitor C1 and an electrolytic capacitor C0 connected in parallel on the input side to form an input filtering unit.

8. The ultra-high voltage electron gun power supply photoisolation sampling circuit according to claim 1, characterized in that, The current and voltage sampling base plate (3) is provided with three sets of sub-circuits with the same circuit structure. Each set of sub-circuits is provided with three terminals, which are respectively connected to the voltage output terminal, current output terminal and local reference ground of the corresponding sub-sampling circuit in the sampling connection circuit (2). A varistor is provided between two adjacent sets of sub-circuits to provide a cross-level surge discharge path between sampling loops at different potentials.

9. The ultra-high voltage electron gun power supply photoisolation sampling circuit according to claim 1, characterized in that, The power supply circuit (1), the sampling connection circuit (2), the current and voltage sampling base plate (3), the sampling processing circuit board (4), the photoelectric conversion circuit board (5), and the optocoupler signal transmission plug-in board (6) are all encapsulated inside the high-voltage insulating oil tank and adopt a modular design with a unified interface, so that any circuit board can be independently disassembled and replaced after damage, without the need for recalibration or adjustment of system parameters.

10. A photoelectric isolation sampling method for an ultra-high voltage electron gun power supply, characterized in that, include: The voltage and current signals of the main high voltage, the auxiliary high voltage and the filament are initially sampled by the sampling connection circuit (2) to obtain the low voltage analog signal; The low-voltage analog signal is sent to the current and voltage sampling base plate (3), and the surge is suppressed by a multi-stage overvoltage clamping network composed of a varistor and a bidirectional diode before being output. The voltage and current signals are amplified, inverted and phase compensated by the sampling processing circuit board (4) to generate a negative polarity analog signal; The negative polarity analog signal is linearly converted into a frequency signal proportional to it by the photoelectric conversion circuit board (5); The frequency signal is converted into an optical signal and electrically isolated output via the optocoupler signal transmission board (6); The main high voltage, the auxiliary high voltage, and the filament sampling channels all use the same hardware processing flow, and each channel operates independently under its floating potential.

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