Multifunctional measurement circuit applicable to Langmuir probe and its control method

Abstract

The present invention discloses a multifunctional measurement circuit applicable to a Langmuir probe and a control method thereof. The circuit at least includes a Langmuir probe, a plurality of relay switches, and a control module. The output end of the first Langmuir probe is connected to the first end of the first voltage sampling module. The second end of the first voltage sampling module is connected to the first end of the second voltage sampling module. The second end of the second voltage sampling module is connected to the output end of the second Langmuir probe. The first end of the first voltage sampling module is further connected to the first end of the current sampling module. The second end of the current sampling module is connected to a scanning power supply or a regulated power supply. The control module is connected to each relay switch and is used to control the on / off of each relay switch so that the circuit can be switched to different circuit modes. The present invention can automatically switch to the corresponding circuit mode according to the number of probes and measurement requirements, effectively improving the operation efficiency of the measurement circuit system and saving maintenance costs and time.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic confinement plasma diagnostics, and in particular to a multifunctional measurement circuit applicable to a Langmuir probe and a control method therefor. Background Art

[0002] Plasma is a state of matter that generally exhibits quasi-neutrality and exists widely in the universe. Plasma has many important applications in the field of science and technology, such as gas discharge, plasma etching, plasma coating, and controlled fusion. A magnetic confinement plasma device uses a special form of magnetic field to confine the electroquasineutral plasma in a specific space, and is mainly applied in the field of magnetic confinement fusion, including fusion devices such as tokamaks and stellarators. Since plasma exists widely in nature, its key parameters such as density and temperature span a wide range, and it is necessary to develop plasma diagnostic techniques to measure the key parameters of plasma.

[0003] The Langmuir probe is a simple and effective diagnostic method that can measure the electron temperature, electron density, ion saturation current, and floating potential of plasma. The Langmuir probe has been widely applied to major magnetic confinement fusion devices and low-temperature plasma devices in the world, and is a general diagnostic method for obtaining plasma information. Usually, the Langmuir probe operates in circuit modes such as floating potential, single probe, Mach probe, and triple probe. Since the Langmuir probe is flexible in application, it is often necessary to design different types of Langmuir probe systems according to different measurement requirements and equip them with corresponding measurement circuit systems, which results in low measurement efficiency and high maintenance costs and time. Therefore, in order to improve the operating efficiency of the measurement circuit system and save maintenance costs and time, it is necessary to study a standardized multifunctional measurement circuit to meet the above-mentioned various circuit mode requirements. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a multifunctional measurement circuit applicable to a Langmuir probe and a control method therefor, which can automatically switch to the corresponding circuit mode according to the number of probes and measurement requirements, effectively improving the operating efficiency of the measurement circuit system and saving maintenance costs and time.

[0005] To achieve the above object, the embodiments of the present invention provide a multifunctional measurement circuit applicable to a Langmuir probe, including a first Langmuir probe, a second Langmuir probe, a first voltage sampling module, a second voltage sampling module, a current sampling module, a scanning power supply, a regulated power supply, a plurality of relay switches, and a control module; wherein, the plurality of relay switches at least include a first relay switch, a second relay switch, a third relay switch, a fourth relay switch, a fifth relay switch, and a sixth relay switch;

[0006] The output end of the first Langmuir probe is connected to the first end of the second relay switch. The second end of the second relay switch is connected to the first end of the first voltage sampling module. The second end of the first voltage sampling module is grounded. The first end of the first relay switch is connected to the first end of the first voltage sampling module. The second end of the first relay switch is connected to the second end of the first voltage sampling module. The second end of the first voltage sampling module is also connected to the first end of the sixth relay switch. The second end of the sixth relay switch is connected to the first end of the second voltage sampling module. The second end of the second voltage sampling module is connected to the output end of the second Langmuir probe.

[0007] The first end of the third relay switch is connected to the first end of the first voltage sampling module. The second end of the third relay switch is connected to the first end of the current sampling module. The second end of the current sampling module is respectively connected to the first end of the fourth relay switch and the first end of the fifth relay switch. The second end of the fourth relay switch is connected to the first end of the scanning power supply. The second end of the scanning power supply is connected to the output end of the second Langmuir probe. The second end of the fifth relay switch is connected to the first end of the voltage stabilizing power supply. The second end of the voltage stabilizing power supply is connected to the output end of the second Langmuir probe.

[0008] The control module is connected to each of the relay switches and is used to control the on / off of each relay switch so that the circuit can be switched to different circuit modes.

[0009] As an improvement of the above solution, the current sampling module includes a current sampling unit and a current branch unit.

[0010] The current sampling unit is connected in parallel at both ends of the current branch unit, and the current branch unit includes a plurality of current branches connected in parallel.

[0011] As an improvement of the above solution, the current branch includes a sampling resistor and a relay switch connected in series with the sampling resistor. Among them, the sampling resistor is a high-power and low-resistance resistor.

[0012] As an improvement of the above solution, the resistance values of the sampling resistors in each current branch are different.

[0013] As an improvement of the above solution, the first voltage sampling module includes a first resistor and a second resistor connected in series with the first resistor. Both ends of the second resistor are respectively connected to two wires of the coaxial cable for measuring the voltage of the first Langmuir probe. Among them, the resistance value of the first resistor is different from that of the second resistor.

[0014] As an improvement of the above solution, the second voltage sampling module includes a third resistor and a fourth resistor connected in series with the third resistor; both ends of the third resistor are respectively connected to two wires of the coaxial cable for measuring the voltage of the second Langmuir probe; wherein, the resistance value of the third resistor is different from that of the fourth resistor.

[0015] As an improvement of the above solution, the current sampling unit includes a fifth resistor and a sixth resistor connected in series with the fifth resistor; both ends of the fifth resistor are respectively connected to two wires of the coaxial cable for measuring the current flowing through the Langmuir probe; wherein, the resistance value of the fifth resistor is different from that of the sixth resistor.

[0016] As an improvement of the above solution, the circuit further includes a first protection module, a second protection module and a third protection module;

[0017] The first end of the first protection module is connected to the output end of the first Langmuir probe, and the second end of the first protection module is connected to the first end of the second relay switch;

[0018] The first end of the second protection module is connected to the output end of the second Langmuir probe, and the second end of the second protection module is connected to the second end of the second voltage sampling module;

[0019] The first end of the third protection module is connected to the second end of the scanning power supply or the second end of the regulated power supply, and the second end of the third protection module is connected to the second end of the second protection module.

[0020] As an improvement of the above solution, the relay switch further includes a seventh relay switch and an eighth relay switch;

[0021] The first end of the seventh relay switch is connected to the second end of the scanning power supply, and the second end of the seventh relay switch is connected to the output end of the second Langmuir probe;

[0022] The first end of the eighth relay switch is connected to the second end of the regulated power supply, and the second end of the eighth relay switch is connected to the output end of the second Langmuir probe.

[0023] The embodiment of the present invention further provides a control method for a multifunctional measurement circuit applicable to a Langmuir probe, which is applied to the multifunctional measurement circuit applicable to a Langmuir probe described in any one of the above, and includes:

[0024] When the control module controls the relay switches to meet the first preset condition, the circuit is in the floating potential mode; wherein, the first preset condition is: the second relay switch is in the closed state, and the first relay switch, the third relay switch, the fourth relay switch, the fifth relay switch, and the sixth relay switch are all in the open state; or, the sixth relay switch is in the closed state, and the first relay switch, the second relay switch, the third relay switch, the fourth relay switch, and the fifth relay switch are all in the open state; or, the second relay switch and the sixth relay switch are both in the closed state, and the first relay switch, the third relay switch, the fourth relay switch, and the fifth relay switch are all in the open state;

[0025] When the control module controls the relay switches to meet the second preset condition, the circuit is in the single probe mode; wherein, the second preset condition is: the first relay switch, the third relay switch, the fourth relay switch, and the sixth relay switch are all in the closed state, and the second relay switch and the fifth relay switch are both in the open state;

[0026] When the control module controls the relay switches to meet the third preset condition, the circuit is in the Mach probe mode; wherein, the third preset condition is: the first relay switch, the third relay switch, the fifth relay switch, and the sixth relay switch are all in the closed state, and the second relay switch and the fourth relay switch are both in the open state;

[0027] When the control module controls the relay switches to meet the fourth preset condition, the circuit is in the three probe mode; wherein, the fourth preset condition is: the second relay switch, the third relay switch, the fifth relay switch, and the sixth relay switch are all in the closed state, and the first relay switch and the fourth relay switch are both in the open state.

[0028] Compared with the prior art, the beneficial effects of a multi-functional measurement circuit applicable to a Langmuir probe and its control method provided by the embodiments of the present invention are as follows: The circuit includes a first Langmuir probe, a second Langmuir probe, a first voltage sampling module, a second voltage sampling module, a current sampling module, a scanning power supply, a regulated power supply, a plurality of relay switches, and a control module; the output end of the first Langmuir probe is connected to the first end of the first voltage sampling module, the second end of the first voltage sampling module is connected to the first end of the second voltage sampling module, and the second end of the second voltage sampling module is connected to the output end of the second Langmuir probe; the first end of the first voltage sampling module is further connected to the first end of the current sampling module, and the second end of the current sampling module is connected to the scanning power supply or the regulated power supply; wherein, a relay switch is connected to each branch, and the control module is connected to each relay switch for controlling the on / off of each relay switch so that the circuit can be switched to different circuit modes. The embodiments of the present invention can automatically switch to the corresponding circuit mode according to the number of probes and measurement requirements, effectively improving the operation efficiency of the measurement circuit system and saving maintenance costs and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 FIG. 6 is a schematic structural diagram of a preferred embodiment of a multi-functional measurement circuit applicable to a Langmuir probe provided by the present invention;

[0030] Figure 2 FIG. 10 is a schematic structural diagram of another preferred embodiment of a multi-functional measurement circuit applicable to a Langmuir probe provided by the present invention;

[0031] Figure 3 FIG. 14 is a schematic circuit diagram of a preferred embodiment of a multi-functional measurement circuit applicable to a Langmuir probe provided by the present invention;

[0032] Figure 4 FIG. 18 is a schematic diagram of the states of relay switches in different circuit modes in a preferred embodiment of a multi-functional measurement circuit applicable to a Langmuir probe provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] See Figure 1As shown, it is a schematic structural diagram of a preferred embodiment of a multi-functional measurement circuit applicable to a Langmuir probe provided by the present invention. The multi-functional measurement circuit applicable to a Langmuir probe includes a first Langmuir probe 1, a second Langmuir probe 2, a first voltage sampling module, a second voltage sampling module, a current sampling module, a scanning power supply, a regulated power supply, a plurality of relay switches, and a control module; wherein, the plurality of relay switches at least includes a first relay switch S1, a second relay switch S2, a third relay switch S3, a fourth relay switch S4, a fifth relay switch S5, and a sixth relay switch S6;

[0035] The output end of the first Langmuir probe 1 is connected to the first end of the second relay switch S2, the second end of the second relay switch S2 is connected to the first end of the first voltage sampling module, and the second end of the first voltage sampling module is grounded; the first end of the first relay switch S1 is connected to the first end of the first voltage sampling module, and the second end of the first relay switch S1 is connected to the second end of the first voltage sampling module; the second end of the first voltage sampling module is also connected to the first end of the sixth relay switch S6, the second end of the sixth relay switch S6 is connected to the first end of the second voltage sampling module, and the second end of the second voltage sampling module is connected to the output end of the second Langmuir probe 2;

[0036] The first end of the third relay switch S3 is connected to the first end of the first voltage sampling module, the second end of the third relay switch S3 is connected to the first end of the current sampling module, and the second end of the current sampling module is respectively connected to the first end of the fourth relay switch S4 and the first end of the fifth relay switch S5; the second end of the fourth relay switch S4 is connected to the first end of the scanning power supply, the second end of the scanning power supply is connected to the output end of the second Langmuir probe 2; the second end of the fifth relay switch S5 is connected to the first end of the regulated power supply, and the second end of the regulated power supply is connected to the output end of the second Langmuir probe 2;

[0037] The control module is connected to each of the relay switches and is used to control the on and off of each of the relay switches so that the circuit can be switched to different circuit modes.

[0038] Specifically, the multifunctional measurement circuit includes a first Langmuir probe, a second Langmuir probe, a first voltage sampling module, a second voltage sampling module, a current sampling module, a scanning power supply, a regulated power supply, multiple relay switches, and a control module. The output end of the first Langmuir probe is connected to the first end of the first voltage sampling module, the second end of the first voltage sampling module is connected to the first end of the second voltage sampling module, and the second end of the second voltage sampling module is connected to the output end of the second Langmuir probe; the first end of the first voltage sampling module is also connected to the first end of the current sampling module, and the second end of the current sampling module is connected to the scanning power supply or the regulated power supply; among them, a relay switch is connected to each branch. The control module is connected to each relay switch and is used to control the on and off of each relay switch so that the circuit can be switched to different circuit modes. The specific control method is as follows:

[0039] The control module controls that ① the second relay switch S2 is in the closed state, and the first relay switch S1, the third relay switch S3, the fourth relay switch S4, the fifth relay switch S5, and the sixth relay switch S6 are all in the open state (at this time, the input probe is the first Langmuir probe, and the output signal is the voltage V of the first Langmuir probe + ); or, ② the sixth relay switch S6 is in the closed state, and the first relay switch S1, the second relay switch S2, the third relay switch S3, the fourth relay switch S4, and the fifth relay switch S5 are all in the open state (at this time, the input probe is the second Langmuir probe, and the output signal is the voltage V of the second Langmuir probe bias ); or, ③ the second relay switch S2 and the sixth relay switch S6 are both in the closed state, and the first relay switch S1, the third relay switch S3, the fourth relay switch S4, and the fifth relay switch S5 are all in the open state (at this time, the input probes are the first Langmuir probe and the second Langmuir probe, and the output signals are the voltage V of the first Langmuir probe + and the voltage V of the second Langmuir probe bias ), the multifunctional measurement circuit is in the floating potential mode. In the floating potential mode, the number of input probes can be one or more, and the number of output channels is the same as the number of input probes, which is used to measure the floating potential in the plasma.

[0040] The control module controls that the first relay switch S1, the third relay switch S3, the fourth relay switch S4, and the sixth relay switch S6 are all in the closed state, and the second relay switch S2 and the fifth relay switch S5 are both in the open state (at this time, the input probe is the second Langmuir probe, and the output signals are the voltage V of the second Langmuir probe bias and the current V flowing through the second Langmuir probe is) When the multi-functional measurement circuit is in the single-probe mode. In the single-probe mode, the number of input probes is one. A scanning power supply is used to scan the bias voltage applied to the probe, and the output signals are the probe voltage and the current flowing through the probe, so as to obtain the volt-ampere characteristic curve, and then the electron temperature and electron density in the plasma are obtained by fitting.

[0041] The control module controls the first relay switch S1, the third relay switch S3, the fifth relay switch S5, and the sixth relay switch S6 to be all in the closed state, and the second relay switch S2 and the fourth relay switch S4 to be all in the open state (at this time, the input probe is the second Langmuir probe, and the output signals are the voltage V of the second Langmuir probe bias and the current V flowing through the second Langmuir probe is ) When the multi-functional measurement circuit is in the Mach probe mode. In the Mach probe mode, the number of input probes is one. A constant bias voltage provided by a regulated power supply is used to measure the saturated ion current, and the output signals are the probe voltage and the current flowing through the probe.

[0042] The control module controls the second relay switch S2, the third relay switch S3, the fifth relay switch S5, and the sixth relay switch S6 to be all in the closed state, and the first relay switch S1 and the fourth relay switch S4 to be all in the open state (at this time, the input probes are the first Langmuir probe and the second Langmuir probe, and the output signals are the voltage V of the first Langmuir probe + , the voltage V of the second Langmuir probe bias and the current V flowing through the Langmuir probe is ) When the multi-functional measurement circuit is in the three-probe mode. In the three-probe mode, the number of input probes is two. A bias voltage is applied to the probes through a regulated power supply, and the output signals are the voltages on the two probes and the current flowing through the probes. It can form a three-probe or four-probe with the floating potential mode in another multi-functional circuit to measure the high-time-resolution electron temperature and density.

[0043] It can be understood that the multi-functional measurement circuit has two Langmuir probe input channels, and the number of access channels can be adjusted according to the actual measurement requirements, and the corresponding circuit mode can be selected. The multi-functional circuit has multiple output parameters, corresponding to corresponding physical quantities in each circuit mode, and the output interface can be adjusted according to the working circuit mode.

[0044] Exemplarily, the scanning power supply in this embodiment is a commercial scanning power supply, which can achieve voltage scanning at a relatively high frequency, output various waveforms, and can remotely set the voltage range, scanning frequency, waveform, and output status of the scanning power supply. The scanning power supply can operate in a single-probe mode. The regulated power supply provides a bias voltage for the probe. A low-noise regulated power supply or a large-capacity capacitor can be used. The regulated power supply can operate in a Mach probe mode and a triple-probe mode. The Langmuir probe is generally made of conductor materials such as graphite or metal, can withstand high temperatures, penetrate into the plasma, and obtain local plasma information. The relay switch is a high-voltage DC relay, which can work under high-voltage conditions and are all normally open switches, that is, they are all in the off state when no control command is received. The relay switches are all controlled by the control module. By setting the state combinations of closing and opening of multiple relay switches, the circuit can be switched to the floating potential mode, single-probe mode, Mach probe mode, or triple-probe mode. The main function of the control module is to switch the circuit mode according to the measurement requirements, that is, to control the states of multiple relay switches. The hardware of the control module is mainly a controller. Commercial acquisition cards produced by manufacturers such as NI and Jianyi can be used, or a control module can be formed by a digital-to-analog converter and a controller. Through the control module hardware, the control program can make the multifunctional measurement circuit operate in the floating potential mode, single-probe mode, Mach probe mode, or triple-probe mode respectively.

[0045] It should be noted that the multifunctional measurement circuit can be integrated into a PCB circuit board, which is suitable for mass production; it can also be integrated into a circuit box composed of an epoxy insulating board and a metal board by welding. During use, multiple circuit boards can be used in cooperation according to actual measurement requirements and operate in appropriate circuit modes respectively to obtain the physical quantities to be measured.

[0046] The multifunctional measurement circuit provided in this embodiment has the main functions of a Langmuir probe for measuring plasma information, can be remotely controlled and switched to the corresponding circuit mode through the control module according to the number of probes and measurement requirements, effectively improves the operation efficiency of the probe measurement circuit system, and saves maintenance costs and time. In addition, this circuit also has the characteristics of reliable signal quality and low noise, and is suitable for high-time-resolution and high-precision physical measurements.

[0047] See Figure 2 As shown in the figure, it is a schematic structural diagram of another preferred embodiment of a multifunctional measurement circuit suitable for a Langmuir probe provided by the present invention. In another preferred embodiment, the current sampling module includes a current sampling unit and a current branch unit;

[0048] The current sampling unit is connected in parallel at both ends of the current branch unit, and the current branch unit includes multiple current branches connected in parallel.

[0049] Specifically, the current sampling module includes a current sampling unit and a current branch unit. Among them, the current sampling unit is connected in parallel at both ends of the current branch unit to measure the magnitude of the passing current. Since the range of the passing current varies greatly, in order to ensure a high measurement signal-to-noise ratio and protect the acquisition system, the current branch unit in this embodiment includes multiple current branches connected in parallel.

[0050] For the measurement parameters with a large variation range in this embodiment, multiple parameter intervals are set in the circuit, and the optimal combination can be selected according to the actual situation to optimize the measurement parameter range and form a standardized circuit module.

[0051] As a preferred solution, the current branch includes a sampling resistor R Z and a relay switch S Z connected in series with the sampling resistor R Z , where the sampling resistor R Z is a high-power and low-resistance resistor.

[0052] Specifically, each current branch includes a sampling resistor R Z and a relay switch S Z connected in series with the sampling resistor R Z . Among them, the sampling resistor R Z is a high-power and low-resistance resistor for measuring the magnitude of the passing current.

[0053] As a preferred solution, the resistance values of the sampling resistors in each current branch are different.

[0054] Specifically, since the range of the passing current varies greatly, in order to ensure a high measurement signal-to-noise ratio and protect the acquisition system, the current branch unit in this embodiment includes multiple current branches connected in parallel, and the resistance values of the sampling resistors in each current branch are different. The optimal high-power and low-resistance resistor can be selected according to the actual measurement requirements, and the relay switch of the corresponding branch can be turned on. For example, the optimal high-power resistors R Z1 , R Z2 , R Z3 are selected and the relay switches S Z1 , S Z2 , S Z3 of the corresponding branches are turned on to switch to the optimal measurement branch. The optimal measurement branch has a high measurement signal-to-noise ratio, and at the same time, the measurement signal amplitude is within the allowable range of the acquisition system, without causing damage to the hardware.

[0055] See Figure 3As shown, it is the circuit schematic diagram of a preferred embodiment of a multi-functional measurement circuit applicable to a Langmuir probe provided by the present invention. Further, the first voltage sampling module includes a first resistor R1 and a second resistor R2 connected in series with the first resistor R1; both ends of the second resistor R2 are respectively connected to two wires of a coaxial cable for measuring the voltage of the first Langmuir probe; wherein, the resistance value of the first resistor R1 is different from that of the second resistor R2.

[0056] Specifically, the first voltage sampling module includes a first resistor R1 and a second resistor R2 connected in series with the first resistor R1. Among them, both the first resistor R1 and the second resistor R2 are high-resistance resistors, but the resistance value of the first resistor R1 is different from that of the second resistor R2. Both ends of the second resistor R2 are respectively connected to two wires of a coaxial cable, and by measuring the voltage difference across the second resistor R2, the voltage output V of the first Langmuir probe is obtained. + 。

[0057] Further, the second voltage sampling module includes a third resistor R3 and a fourth resistor R4 connected in series with the third resistor R3; both ends of the third resistor R3 are respectively connected to two wires of a coaxial cable for measuring the voltage of the second Langmuir probe; wherein, the resistance value of the third resistor R3 is different from that of the fourth resistor R4.

[0058] Specifically, the second voltage sampling module includes a third resistor R3 and a fourth resistor R4 connected in series with the third resistor R3. Among them, both the third resistor R3 and the fourth resistor R4 are high-resistance resistors, but the resistance value of the third resistor R3 is different from that of the fourth resistor R4. Both ends of the third resistor R3 are respectively connected to two wires of a coaxial cable, and by measuring the voltage difference across the third resistor R3, the voltage output V of the second Langmuir probe is obtained. bias 。

[0059] Further, the current sampling unit includes a fifth resistor R5 and a sixth resistor R6 connected in series with the fifth resistor R5; both ends of the fifth resistor R5 are respectively connected to two wires of a coaxial cable for measuring the current flowing through the Langmuir probe; wherein, the resistance value of the fifth resistor R5 is different from that of the sixth resistor R6.

[0060] Specifically, the current sampling unit includes a fifth resistor R5 and a sixth resistor R6 connected in series with the fifth resistor R5. Among them, both the fifth resistor R5 and the sixth resistor R6 are high-resistance resistors, but the resistance value of the fifth resistor R5 is different from that of the sixth resistor R6. Both ends of the fifth resistor R5 are respectively connected to two wires of a coaxial cable, and by measuring the current flowing through the fifth resistor R5, the V flowing through the Langmuir probe is obtained. is 。

[0061] Further, the circuit further includes a first protection module F1, a second protection module F2, and a third protection module F3;

[0062] The first end of the first protection module F1 is connected to the output end of the first Langmuir probe 1, and the second end of the first protection module F1 is connected to the first end of the second relay switch S2;

[0063] The first end of the second protection module F2 is connected to the output end of the second Langmuir probe 2, and the second end of the second protection module F2 is connected to the second end of the second voltage sampling module;

[0064] The first end of the third protection module F3 is connected to the second end of the scanning power supply or the second end of the regulated power supply, and the second end of the third protection module F3 is connected to the second end of the second protection module F2.

[0065] Specifically, the multifunctional measurement circuit further includes a first protection module, a second protection module, and a third protection module. Among them, the first end of the first protection module is connected to the output end of the first Langmuir probe, and the second end of the first protection module is connected to the first end of the second relay switch. The first end of the second protection module is connected to the output end of the second Langmuir probe, and the second end of the second protection module is connected to the second end of the second voltage sampling module. The first end of the third protection module is connected to the second end of the scanning power supply or the second end of the regulated power supply, and the second end of the third protection module is connected to the second end of the second protection module.

[0066] Exemplarily, the protection module in this embodiment can adopt a glass fuse, a ceramic fuse, or a self - restoring fuse, which is used to protect circuit elements and the acquisition system.

[0067] Further, the relay switch further includes a seventh relay switch S7 and an eighth relay switch S8;

[0068] The first end of the seventh relay switch S7 is connected to the second end of the scanning power supply, and the second end of the seventh relay switch S7 is connected to the output end of the second Langmuir probe 2;

[0069] The first end of the eighth relay switch S8 is connected to the second end of the regulated power supply, and the second end of the eighth relay switch S8 is connected to the output end of the second Langmuir probe 2.

[0070] Specifically, the relay switch further includes a seventh relay switch and an eighth relay switch. Among them, the first end of the seventh relay switch is connected to the second end of the scanning power supply, and the second end of the seventh relay switch is connected to the output end of the second Langmuir probe. In this embodiment, a relay switch is respectively connected in series at both ends of the scanning power supply, so as to cut off the connection at both ends of the scanning power supply when replacing the scanning power supply. The first end of the eighth relay switch is connected to the second end of the regulated power supply, and the second end of the eighth relay switch is connected to the output end of the second Langmuir probe, so as to facilitate the replacement of the regulated power supply. In this embodiment, a relay switch is respectively connected in series at both ends of the regulated power supply, so as to cut off the connection at both ends of the regulated power supply when replacing the regulated power supply.

[0071] See Figure 4 As shown, it is a schematic diagram of the states of relay switches in different circuit modes in a preferred embodiment of a multifunctional measurement circuit applicable to a Langmuir probe provided by the present invention.

[0072] In this embodiment, there are three floating potential modes. The first is floating potential 1: the input probe is the first Langmuir probe 1, and the output signal is the voltage V of the first Langmuir probe 1 + ; the second is floating potential 2: the input probe is the second Langmuir probe 2, and the output signal is the voltage V of the second Langmuir probe 2 bias ; the third is floating potential 12: the input probes are the first Langmuir probe 1 and the second Langmuir probe 2, and the output signals are the voltage V of the first Langmuir probe 1 + and the voltage V of the second Langmuir probe 2 bias . In the floating potential mode, the number of input probes can be one or two, and the number of output channels is the same as the number of input probes, which is used to measure the floating potential in the plasma.

[0073] In the single probe mode, the number of input probes is one, that is, the second Langmuir probe 2. By scanning the bias voltage applied to the second Langmuir probe 2 through the scanning power supply, the output signal V bias is the voltage of the second Langmuir probe 2, and V is is the current flowing through the second Langmuir probe 2, so as to obtain the volt-ampere characteristic curve, and then fit to obtain the electron temperature and electron density in the plasma.

[0074] In the Mach probe mode, the number of input probes is one, that is, the second Langmuir probe 2. By applying a stable bias voltage through the regulated power supply to obtain a saturated ion current, the output signals are the voltage V bias of the second Langmuir probe 2 and the current V is flowing through the second Langmuir probe 2.

[0075] In the three-probe mode, the number of input probes is two, namely the first Langmuir probe 1 and the second Langmuir probe 2. A bias voltage is applied to the two probes through a regulated power supply, and the output signals are the voltage V of the first Langmuir probe 1 + , the voltage V of the second Langmuir probe 2 bias and the current V flowing through the Langmuir probe is . It can form a three-probe or four-probe with the floating potential mode in another multifunctional circuit to measure the electron temperature and density with high time resolution.

[0076] Correspondingly, the present invention also provides a control method for a multifunctional measurement circuit applicable to a Langmuir probe, which is applied to the multifunctional measurement circuit applicable to a Langmuir probe described in any one of the above. The control method for the multifunctional measurement circuit applicable to a Langmuir probe includes:

[0077] When the control module controls the relay switch to meet the first preset condition, the circuit is in the floating potential mode; wherein, the first preset condition is: the second relay switch is in the closed state, and the first relay switch, the third relay switch, the fourth relay switch, the fifth relay switch and the sixth relay switch are all in the open state; or, the sixth relay switch is in the closed state, and the first relay switch, the second relay switch, the third relay switch, the fourth relay switch and the fifth relay switch are all in the open state; or, the second relay switch and the sixth relay switch are both in the closed state, and the first relay switch, the third relay switch, the fourth relay switch and the fifth relay switch are all in the open state;

[0078] When the control module controls the relay switch to meet the second preset condition, the circuit is in the single-probe mode; wherein, the second preset condition is: the first relay switch, the third relay switch, the fourth relay switch and the sixth relay switch are all in the closed state, and the second relay switch and the fifth relay switch are both in the open state;

[0079] When the control module controls the relay switch to meet the third preset condition, the circuit is in the Mach probe mode; wherein, the third preset condition is: the first relay switch, the third relay switch, the fifth relay switch and the sixth relay switch are all in the closed state, and the second relay switch and the fourth relay switch are both in the open state;

[0080] When the control module controls the relay switch to meet the fourth preset condition, the circuit is in the three-probe mode; wherein, the fourth preset condition is: the second relay switch, the third relay switch, the fifth relay switch and the sixth relay switch are all in the closed state, and the first relay switch and the fourth relay switch are both in the open state.

[0081] Specifically, the control module controls ① the second relay switch S2 to be in the closed state, and the first relay switch S1, the third relay switch S3, the fourth relay switch S4, the fifth relay switch S5, and the sixth relay switch S6 are all in the open state. At this time, the input probe is the first Langmuir probe, and the output signal is the voltage V of the first Langmuir probe + ; or ② the sixth relay switch S6 is in the closed state, and the first relay switch S1, the second relay switch S2, the third relay switch S3, the fourth relay switch S4, and the fifth relay switch S5 are all in the open state. At this time, the input probe is the second Langmuir probe, and the output signal is the voltage V of the second Langmuir probe bias ; or ③ the second relay switch S2 and the sixth relay switch S6 are both in the closed state, and the first relay switch S1, the third relay switch S3, the fourth relay switch S4, and the fifth relay switch S5 are all in the open state. At this time, the input probes are the first Langmuir probe and the second Langmuir probe, and the output signals are the voltage V of the first Langmuir probe + and the voltage V of the second Langmuir probe bias When this is the case, the multifunctional measurement circuit is in the floating potential mode. In the floating potential mode, the number of input probes can be one or more, and the number of output channels is the same as the number of input probes, which is used to measure the floating potential in the plasma.

[0082] When the control module controls the first relay switch S1, the third relay switch S3, the fourth relay switch S4, and the sixth relay switch S6 to be all in the closed state, and the second relay switch S2 and the fifth relay switch S5 are both in the open state, the multifunctional measurement circuit is in the single probe mode. At this time, the input probe is the second Langmuir probe 2, and the output signals are the voltage V of the second Langmuir probe 2 bias and the current V flowing through the second Langmuir probe 2 is . In the single probe mode, the number of input probes is one. A scanning power supply is used to scan the bias voltage applied to the probe, and the output signals are the probe voltage and the current flowing through the probe, so as to obtain the volt-ampere characteristic curve, and then the electron temperature and electron density in the plasma are obtained by fitting.

[0083] When the control module controls the first relay switch S1, the third relay switch S3, the fifth relay switch S5, and the sixth relay switch S6 to be all in the closed state, and the second relay switch S2 and the fourth relay switch S4 are both in the open state, the multifunctional measurement circuit is in the Mach probe mode. At this time, the input probe is the second Langmuir probe 2, and the output signals are the voltage V of the second Langmuir probe 2 bias and the current V flowing through the second Langmuir probe 2 is。In the Mach probe mode, the number of input probes is one. A constant bias voltage provided by a regulated power supply is used to measure the saturated ion current, and the output signals are the probe voltage and the current flowing through the probe.

[0084] When the control module controls the second relay switch S2, the third relay switch S3, the fifth relay switch S5, and the sixth relay switch S6 to be all in the closed state, and the first relay switch S1 and the fourth relay switch S4 to be all in the open state, the multifunctional measurement circuit is in the three-probe mode. At this time, the input probes are the first Langmuir probe 1 and the second Langmuir probe 2, and the output signals are the voltage V of the first Langmuir probe 1 + , the voltage V of the second Langmuir probe 2 bias and the current V flowing through the Langmuir probe. is 。In the three-probe mode, the number of input probes is two. A bias voltage is applied to the probes through a regulated power supply, and the output signals are the voltages on the two probes and the current flowing through the probes. It can form a three-probe or four-probe with the floating potential mode in another multifunctional circuit to measure the electron temperature and density with high time resolution.

[0085] It can be understood that the multifunctional measurement circuit has two Langmuir probe input channels, and the number of access channels can be adjusted according to the actual measurement requirements, and the corresponding circuit mode can be selected. The multifunctional circuit has multiple output parameters, corresponding to corresponding physical quantities in each circuit mode, and the output interface can be adjusted according to the working circuit mode.

[0086] The embodiment of the present invention provides a multifunctional measurement circuit applicable to Langmuir probes and its control method. The circuit includes a first Langmuir probe, a second Langmuir probe, a first voltage sampling module, a second voltage sampling module, a current sampling module, a scanning power supply, a regulated power supply, multiple relay switches, and a control module; the output end of the first Langmuir probe is connected to the first end of the first voltage sampling module, the second end of the first voltage sampling module is connected to the first end of the second voltage sampling module, and the second end of the second voltage sampling module is connected to the output end of the second Langmuir probe; the first end of the first voltage sampling module is also connected to the first end of the current sampling module, and the second end of the current sampling module is connected to the scanning power supply or the regulated power supply; wherein, each branch is connected with a relay switch, and the control module is connected to each relay switch for controlling the on-off of each relay switch so that the circuit can be switched to different circuit modes. The embodiment of the present invention can automatically switch to the corresponding circuit mode according to the number of probes and measurement requirements, effectively improving the operation efficiency of the measurement circuit system and saving maintenance costs and time.

[0087] It should be noted that the system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the attached drawings of the system embodiments provided by the present invention, the connection relationships between modules indicate that there are communication connections between them, which can be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0088] The above is the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A multifunctional measurement circuit applicable to a Langmuir probe, characterized in that, It includes a first Langmuir probe, a second Langmuir probe, a first voltage sampling module, a second voltage sampling module, a current sampling module, a scanning power supply, a regulated power supply, multiple relay switches, and a control module; among them, the multiple relay switches at least include a first relay switch, a second relay switch, a third relay switch, a fourth relay switch, a fifth relay switch, and a sixth relay switch; The output end of the first Langmuir probe is connected to the first end of the second relay switch, the second end of the second relay switch is connected to the first end of the first voltage sampling module, and the second end of the first voltage sampling module is grounded; the first end of the first relay switch is connected to the first end of the first voltage sampling module, and the second end of the first relay switch is connected to the second end of the first voltage sampling module; the second end of the first voltage sampling module is also connected to the first end of the sixth relay switch, the second end of the sixth relay switch is connected to the first end of the second voltage sampling module, and the second end of the second voltage sampling module is connected to the output end of the second Langmuir probe; The first end of the third relay switch is connected to the first end of the first voltage sampling module, the second end of the third relay switch is connected to the first end of the current sampling module, and the second end of the current sampling module is respectively connected to the first ends of the fourth relay switch and the fifth relay switch; the second end of the fourth relay switch is connected to the first end of the scanning power supply, and the second end of the scanning power supply is connected to the output end of the second Langmuir probe; the second end of the fifth relay switch is connected to the first end of the regulated power supply, and the second end of the regulated power supply is connected to the output end of the second Langmuir probe; The control module is connected to each of the relay switches and is used to control the on / off of each relay switch so that the circuit can be switched to different circuit modes.

2. The multi-functional measurement circuit applicable to a Langmuir probe according to claim 1, characterized in that The current sampling module includes a current sampling unit and a current branch unit; The current sampling unit is connected in parallel at both ends of the current branch unit, and the current branch unit includes multiple current branches connected in parallel.

3. The multifunctional measurement circuit applicable to a Langmuir probe according to claim 2, wherein The current branch includes a sampling resistor and a relay switch connected in series with the sampling resistor, where the sampling resistor is a high-power and low-resistance resistor.

4. The multi-functional measurement circuit applicable to a Langmuir probe according to claim 3, characterized in that The resistance values of the sampling resistors in each current branch are different.

5. The multi-functional measurement circuit applicable to a Langmuir probe according to any one of claims 2 to 4, characterized in that The first voltage sampling module includes a first resistor and a second resistor connected in series with the first resistor; the two ends of the second resistor are respectively connected to the two wires of the coaxial cable for measuring the voltage of the first Langmuir probe; among them, the resistance value of the first resistor is different from that of the second resistor.

6. The multi-functional measurement circuit applicable to a Langmuir probe according to claim 5, characterized in that, The second voltage sampling module includes a third resistor and a fourth resistor connected in series with the third resistor; the two ends of the third resistor are respectively connected to the two wires of the coaxial cable for measuring the voltage of the second Langmuir probe; among them, the resistance value of the third resistor is different from that of the fourth resistor.

7. The multifunctional measurement circuit applicable to a Langmuir probe according to claim 6, characterized in that, The current sampling unit includes a fifth resistor and a sixth resistor connected in series with the fifth resistor; both ends of the fifth resistor are respectively connected to two wires of the coaxial cable for measuring the current flowing through the Langmuir probe; wherein, the resistance value of the fifth resistor is different from that of the sixth resistor.

8. The multi-functional measurement circuit applicable to a Langmuir probe according to claim 7, characterized in that The circuit further includes a first protection module, a second protection module, and a third protection module; The first end of the first protection module is connected to the output end of the first Langmuir probe, and the second end of the first protection module is connected to the first end of the second relay switch; The first end of the second protection module is connected to the output end of the second Langmuir probe, and the second end of the second protection module is connected to the second end of the second voltage sampling module; The first end of the third protection module is connected to the second end of the scanning power supply or the second end of the regulated power supply, and the second end of the third protection module is connected to the second end of the second protection module.

9. The multi-functional measurement circuit applicable to a Langmuir probe according to claim 8, characterized in that, The relay switch further includes a seventh relay switch and an eighth relay switch; The first end of the seventh relay switch is connected to the second end of the scanning power supply, and the second end of the seventh relay switch is connected to the output end of the second Langmuir probe; The first end of the eighth relay switch is connected to the second end of the regulated power supply, and the second end of the eighth relay switch is connected to the output end of the second Langmuir probe.

10. A control method for a multi-functional measurement circuit applicable to a Langmuir probe, which is applied to the multi-functional measurement circuit applicable to a Langmuir probe according to any one of claims 1 to 9, characterized in that, Including: When the control module controls the relay switch to meet the first preset condition, the circuit is in the floating potential mode; wherein, the first preset condition is: the second relay switch is in the closed state, and the first relay switch, the third relay switch, the fourth relay switch, the fifth relay switch, and the sixth relay switch are all in the open state; or, the sixth relay switch is in the closed state, and the first relay switch, the second relay switch, the third relay switch, the fourth relay switch, and the fifth relay switch are all in the open state; or, both the second relay switch and the sixth relay switch are in the closed state, and the first relay switch, the third relay switch, the fourth relay switch, and the fifth relay switch are all in the open state; When the control module controls the relay switch to meet the second preset condition, the circuit is in the single probe mode; wherein, the second preset condition is: the first relay switch, the third relay switch, the fourth relay switch, and the sixth relay switch are all in the closed state, and the second relay switch and the fifth relay switch are all in the open state; When the control module controls the relay switch to meet the third preset condition, the circuit is in the Mach probe mode; wherein, the third preset condition is: the first relay switch, the third relay switch, the fifth relay switch, and the sixth relay switch are all in the closed state, and the second relay switch and the fourth relay switch are all in the open state; When the control module controls the relay switches to meet the fourth preset condition, the circuit is in the three-probe mode; wherein, the fourth preset condition is that the second relay switch, the third relay switch, the fifth relay switch, and the sixth relay switch are all in the closed state, and the first relay switch and the fourth relay switch are both in the open state.

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