Plasma intensity compensation circuit based on load characteristics

Abstract

The utility model discloses a plasma intensity compensating circuit based on load characteristics, which comprises a light intensity acquisition circuit, a light intensity semaphore isolation front follower circuit, a light intensity signal isolation circuit, a light intensity signal differential amplification circuit and a light intensity semaphore isolation rear follower circuit. Plasma is sensed in real time through the light intensity sensor, plasma characteristic related variables are obtained, the plasma characteristic related variables are converted into plasma intensity compensation semaphore, the plasma intensity compensation semaphore is sent to the power source end after being isolated, the power source end carries out compensation output according to the compensation semaphore, and the whole plasma intensity compensation process is completed. The plasma intensity is always maintained in a reasonable range, the stability and uniformity of the plasma application effect are ensured, the safety of plasma application is enhanced, the application effect of industrial production application is improved, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of plasma application, and in particular relates to a plasma intensity compensation circuit based on load characteristics. Background Art

[0002] Plasma is generated under atmospheric pressure and has been widely used in industrial production due to its low cost, easy integration into production lines, no consumables, uninterrupted use, and convenient maintenance. In the industrial application of plasma, the core indicator that affects the application effect is the intensity of the plasma: if the intensity is too low, the application effect is poor; if the intensity is too high, it is easy to damage the material; if the intensity fluctuates greatly, the application effect is unstable, sometimes good and sometimes bad, resulting in low production efficiency.

[0003] Based on this demand, a plasma intensity compensation circuit based on load characteristics is proposed, which is used to track and compensate the plasma intensity in real time during the production process, so as to maintain the plasma intensity within a good application range, improve the application effect and enhance the production efficiency. Summary of the invention

[0004] To achieve the above-mentioned purpose, the technical scheme of the present invention is as follows: a plasma intensity compensation circuit based on load characteristics, the circuit comprising a light intensity acquisition circuit, a light intensity signal quantity isolation pre-following circuit, a light intensity signal isolation circuit, a light intensity signal differential amplification circuit and a light intensity signal quantity isolation post-following circuit. By arranging a plasma light intensity sensor in the reactor, the plasma is sensed in real time by the light intensity sensor and the plasma characteristic related variables are obtained, and converted into a plasma intensity compensation signal quantity, which is sent to the power supply end after isolation. The power supply end performs compensation output according to the compensation signal quantity to complete the entire plasma intensity compensation process.

[0005] Based on the above technical features, the equipment for generating plasma is divided into three parts: 1. Plasma reactor, which is used to directly generate plasma; 2. Plasma atmosphere, which is the gas source for generating plasma, can be air or an atmosphere designated for special purposes, usually directly applied to the plasma reactor; 3. Plasma power supply, which is used to drive the plasma reactor, ionize the atmosphere in the reactor, and form plasma. During the operation of the plasma equipment, changes in state parameters such as the temperature change of the plasma reactor, the temperature, concentration and pressure change of the plasma atmosphere, and the voltage, current, frequency and power change of the plasma power supply will all affect the intensity of the plasma. Among the above state parameters, the fluctuations of the plasma atmosphere and the reactor are attributed to the changes at the load end, and the fluctuations of the plasma power supply are attributed to the changes at the power supply end, and the load end is controlled by the excitation of the power supply end. The most convenient way to characterize the change of plasma intensity in real time is the change of plasma light intensity, and a plasma light intensity sensor can be used as a sensing element.

[0006] As an improvement of the present utility model, the light intensity collection circuit includes an integrated operational amplifier module U1.1, an external port plasma+, and an external port plasma-, the two external ports plasma+ and plasma- are used to connect a passive plasma light intensity sensor, sampling resistors (R1~R5) and an output resistor R6. In the light intensity collection circuit, after the series voltage division of the sampling resistors R1 and R2, a DC voltage signal negatively correlated with the plasma light intensity is obtained.

[0007] Based on the above technical features, the above devices constitute a light intensity collection circuit. The plasma light intensity sensor is a negative resistance device, that is, the stronger the plasma light intensity, the smaller the external impedance of the sensor. After the series voltage division of the sampling resistors R1 and R2, a DC voltage signal that is negatively correlated with the plasma light intensity is obtained. Generally, the full scale of light intensity perception is set to 10000cd. At this time, the output DC voltage signal reaches the minimum value of 1V. As the light intensity gradually decreases, the DC voltage signal will gradually increase.

[0008] As an improvement of the utility model, the light intensity signal isolation front follower circuit includes an integrated operational amplifier module U1.2, filter resistors (R7, R8), and filter capacitors (C1, C2). After the light intensity signal is converted into a negatively correlated DC voltage signal, it is subjected to impedance transformation and filtering processing to obtain a smooth and real light intensity signal for use by the subsequent circuit.

[0009] Based on the above technical features, in the light intensity signal isolation front follower circuit, generally, the filter parameter setting is related to the excitation frequency of the plasma power supply, and the filter cutoff frequency is usually set to 1 / 10 of the excitation frequency.

[0010] As an improvement of the utility model, the DC voltage isolation conversion integrated chip U3 forms a light intensity signal isolation circuit. The plasma light intensity sensor is placed inside the plasma reactor, and there is a high voltage field strength inside the plasma reactor. In order to avoid signal interference caused by the high voltage field strength and safety protection of the subsequent circuit, the sampling signal needs to be electrically isolated. The sampling signal after isolation processing will not be interfered by the high voltage field strength, can more accurately reflect the trend of plasma intensity, and is more friendly to the subsequent weak current system.

[0011] As an improvement of the present utility model, the light intensity signal differential amplifier circuit includes an integrated operational amplifier module U2.1, differential amplifier resistors (R9~R12) and an output resistor R13. The light intensity signal differential amplifier circuit restores the light intensity voltage signal of the isolated light intensity signal to obtain an isolated voltage signal that is negatively correlated with the light intensity signal.

[0012] Based on the above technical features, generally, the voltage signal is reasonably scaled according to the voltage range adapted by the sampling system.

[0013] As an improvement of the present utility model, the light intensity signal isolation follower circuit includes an integrated operational amplifier module U2.2, a filter resistor R14 and a filter capacitor C3. In the light intensity signal isolation follower circuit, after obtaining the isolated plasma light intensity voltage signal, impedance matching and filtering are performed.

[0014] Based on the above technical features, in order to better match with the subsequent circuit (usually the digital ADC acquisition channel), after obtaining the isolated plasma light intensity voltage signal, impedance matching and filtering processing are required to better connect with the subsequent circuit system. Generally, the filter parameter setting is related to the excitation frequency of the plasma power supply, and the filter cutoff frequency is usually set to 1 / 10 of the excitation frequency.

[0015] As an improvement of the utility model, in the light intensity collection circuit, port 3 of the integrated operational amplifier module U1.1 is connected to one end of the sampling resistor R5, the other end of the sampling resistor R5 is connected to one end of the sampling resistor R1, and is connected to the positive end of the plasma light intensity sensor; the other end of the sampling resistor R1 is connected to the positive power supply terminal VCC; port 2 of the integrated operational amplifier module U1.1 is connected to one end of the sampling resistor R3, and is connected to one end of the sampling resistor R4, the other end of the sampling resistor R3 is connected to the negative power supply terminal GND, and the other end of the sampling resistor R4 is connected to port 7 of the integrated operational amplifier module U1.1; port 8 of the integrated operational amplifier module U1.1 is connected to the positive power supply terminal VCC, and port 4 of the integrated operational amplifier module U1.1 is connected to the negative power supply terminal GND; one end of the sampling resistor R2 is connected to the negative power supply terminal GND, and the other end is connected to the negative end of the plasma light intensity sensor; one end of the output resistor R6 is connected to port 7 of the integrated operational amplifier module U1.1.

[0016] As an improvement of the utility model, in the light intensity signal isolation front follower circuit, port 5 of the integrated operational amplifier module U1.2 is connected to the other end of the output resistor R6; port 6 of the integrated operational amplifier module U1.2 is connected to port 7 of the integrated operational amplifier module U1.2; one end of the filter resistor R7 is connected to port 7 of the integrated operational amplifier module U1.2, and the other end is connected to one end of the filter capacitor C1, and is connected to one end of the filter resistor R8; the other end of the filter resistor R8 is connected to one end of the filter capacitor C2.

[0017] As an improvement of the utility model, in the light intensity signal isolation circuit, ports 1-4 of the DC voltage isolation conversion integrated chip U3 are the isolation front end, and ports 5-8 are the isolation back end; the isolation front and back ends are powered by independent voltage sources, and generally, the voltage level of the independent voltage sources is at least 1.5 times the highest voltage of the plasma. Port 2 of the DC voltage isolation conversion integrated chip U3 is connected to the filter capacitor C2; ports 7 and 6 of the DC voltage isolation conversion integrated chip U3 output the isolation voltage in a differential form.

[0018] As an improvement of the present utility model, one end of the differential amplifier resistor R9 in the light intensity signal differential amplifier circuit is connected to port 7 of the DC voltage isolation conversion integrated chip U3, and the other end is connected to port 3 of the integrated operational amplifier module U2.1, and is connected to one end of the differential amplifier resistor R12; one end of the differential amplifier resistor R10 is connected to port 6 of the DC voltage isolation conversion integrated chip U3, and the other end is connected to port 2 of the integrated operational amplifier module U2.1, and is connected to one end of the differential amplifier resistor R11, and the other end of the differential amplifier resistor R11 is connected to port 1 of the integrated operational amplifier module U2.1, and is connected to one end of the output resistor R13.

[0019] As an improvement of the present utility model, port 5 of the integrated operational amplifier module U2.2 is connected to the other end of the output resistor R13; port 7 of the integrated operational amplifier module U2.2 is connected to port 6 of the integrated operational amplifier module U2.2, and is connected to one end of the filter resistor R14, the other end of the filter resistor R14 is connected to the filter capacitor C3, and is connected to the external output port plasma-sense.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: the plasma intensity compensation circuit proposed by the utility model, by arranging a plasma light intensity sensor in the reactor, senses the plasma in real time and obtains plasma characteristic related variables through the light intensity sensor, and converts them into plasma intensity compensation signal quantities, which are sent to the power supply end after isolation. The power supply end performs compensation output according to the compensation signal quantity to complete the entire plasma intensity compensation process. Through real-time closed-loop compensation of plasma intensity, it is ensured that the plasma intensity is always maintained within a reasonable range, thereby ensuring the stability and uniformity of the plasma application effect, enhancing the safety of plasma application, improving the application effect of industrial production application, and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 4 is a structural diagram of the plasma intensity compensation circuit in this embodiment. DETAILED DESCRIPTION

[0022] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0023] Example: Figure 1 As shown, this embodiment is a plasma intensity compensation circuit based on load characteristics, including a light intensity acquisition circuit, a light intensity signal isolation pre-following circuit, a light intensity signal isolation circuit, a light intensity signal differential amplification circuit, and a light intensity signal isolation post-following circuit.

[0024] Furthermore, U1.1 is an integrated operational amplifier module 1.1; the two external ports plasma+ and plasma- are used to connect the passive plasma light intensity sensor; R1, R2, R3, R4, and R5 are sampling resistors; R6 is an output resistor; the above devices constitute a light intensity acquisition circuit. The plasma light intensity sensor is a negative resistance device, that is, the stronger the plasma light intensity, the smaller the external impedance of the sensor. After the series voltage division of the sampling resistors R1 and R2, a DC voltage signal that is negatively correlated with the plasma light intensity is obtained. Generally, the full scale of the light intensity perception is set to 10000cd. At this time, the output DC voltage signal reaches the minimum value of 1V. As the light intensity gradually decreases, the DC voltage signal will gradually increase.

[0025] Port 3 of the integrated operational amplifier module U1.1 is connected to one end of the sampling resistor R5, the other end of the sampling resistor R5 is connected to one end of the sampling resistor R1, and is connected to the positive end of the plasma light intensity sensor; the other end of the sampling resistor R1 is connected to the positive power supply terminal VCC; port 2 of the integrated operational amplifier module U1.1 is connected to one end of the sampling resistor R3, and is connected to one end of the sampling resistor R4, the other end of the sampling resistor R3 is connected to the negative power supply terminal GND, and the other end of the sampling resistor R4 is connected to port 7 of the integrated operational amplifier module U1.1; port 8 of the integrated operational amplifier module U1.1 is connected to the positive power supply terminal VCC, and port 4 of the integrated operational amplifier module U1.1 is connected to the negative power supply terminal GND; one end of the sampling resistor R2 is connected to the negative power supply terminal GND, and the other end is connected to the negative end of the plasma light intensity sensor; one end of the output resistor R6 is connected to port 7 of the integrated operational amplifier module U1.1.

[0026] Furthermore, U1.2 is an integrated operational amplifier module 1.2; R7 and R8 are filter resistors; C1 and C2 are filter capacitors; the above devices constitute a light intensity signal isolation front-follower circuit. After the light intensity signal is converted into a negatively correlated DC voltage signal, it needs to be processed by impedance transformation and filtering to obtain a smooth and real light intensity signal for use by the subsequent circuit. Generally, the filter parameter setting is related to the excitation frequency of the plasma power supply, and the filter cutoff frequency is usually set to 1 / 10 of the excitation frequency.

[0027] Port 5 of the integrated operational amplifier module U1.2 is connected to the other end of the output resistor R6; port 6 of the integrated operational amplifier module U1.2 is connected to port 7 of the integrated operational amplifier module U1.2; one end of the filter resistor R7 is connected to port 7 of the integrated operational amplifier module U1.2, and the other end is connected to one end of the filter capacitor C1 and to one end of the filter resistor R8; the other end of the filter resistor R8 is connected to one end of the filter capacitor C2.

[0028] Furthermore, U3 is a DC voltage isolation conversion integrated chip; the above devices constitute a light intensity signal isolation circuit. The plasma light intensity sensor is placed inside the plasma reactor, and there is a high voltage field strength inside the plasma reactor. In order to avoid signal interference caused by the high voltage field strength and the safety protection of the subsequent circuit, the sampling signal needs to be electrically isolated. The sampling signal after isolation will not be interfered by the high voltage field strength, can more accurately reflect the trend of plasma intensity, and is more friendly to the subsequent weak current system. Ports 1-4 of the DC voltage isolation conversion integrated chip U3 are the isolation front end, and ports 5-8 are the isolation back end; the isolation front and back ends are powered by independent voltage sources. Generally, the voltage level of the independent voltage sources is at least 1.5 times the highest plasma voltage.

[0029] Port 2 of the DC voltage isolation conversion integrated chip U3 is connected to the filter capacitor C2; Port 7 and port 6 of the DC voltage isolation conversion integrated chip U3 output the isolation voltage in a differential form.

[0030] Furthermore, U2.1 is an integrated operational amplifier module 2.1; R9, R10, R11, and R12 are differential amplifier resistors; and R13 is an output resistor. The above devices constitute a light intensity signal differential amplifier circuit. The differential amplifier circuit restores the light intensity voltage signal of the isolated light intensity signal to obtain an isolated voltage signal that is negatively correlated with the light intensity signal. Generally, the voltage signal is reasonably scaled according to the voltage range adapted by the sampling system.

[0031] One end of the differential amplifier resistor R9 is connected to port 7 of the DC voltage isolation conversion integrated chip U3, and the other end is connected to port 3 of the integrated operational amplifier module U2.1, and is connected to one end of the differential amplifier resistor R12; one end of the differential amplifier resistor R10 is connected to port 6 of the DC voltage isolation conversion integrated chip U3, and the other end is connected to port 2 of the integrated operational amplifier module U2.1, and is connected to one end of the differential amplifier resistor R11, and the other end of the differential amplifier resistor R11 is connected to port 1 of the integrated operational amplifier module U2.1, and is connected to one end of the output resistor R13.

[0032] Furthermore, U2.2 is the integrated operational amplifier module 2.2; R14 is the filter resistor; C3 is the filter capacitor; the above devices constitute the light intensity signal isolation follower circuit. In order to better match with the subsequent circuit (usually the digital ADC acquisition channel), after obtaining the isolated plasma light intensity voltage signal, impedance matching and filtering processing are required to better connect with the subsequent circuit system. Generally, the filter parameter setting is related to the excitation frequency of the plasma power supply, and the filter cutoff frequency is usually set to 1 / 10 of the excitation frequency.

[0033] Port 5 of the integrated operational amplifier module U2.2 is connected to the other end of the output resistor R13; port 7 of the integrated operational amplifier module U2.2 is connected to port 6 of the integrated operational amplifier module U2.2, and is connected to one end of the filter resistor R14, the other end of the filter resistor R14 is connected to the filter capacitor C3, and is connected to the external output port plasma-sense.

[0034] For the above specific embodiment, the plasma light intensity compensation process is as follows:

[0035] Light intensity decreases↓→plasma+ and plasma- impedances increase↑→light intensity collection circuit output voltage increases↑→light intensity signal following circuit voltage increases before isolation↑→light intensity signal isolation circuit voltage increases↑→light intensity signal differential amplifier circuit increases↑→light intensity signal following circuit increases after isolation↑→plasma-sense voltage signal increases↑→plasma power system output increases↑→light intensity increases↑. The compensation process when light intensity increases is the opposite of the above process.

[0036] It should be noted that the above content merely illustrates the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications all fall within the protection scope of the claims of the present invention.

Claims

1. A plasma intensity compensation circuit based on load characteristics, characterized in that: The circuit includes a light intensity acquisition circuit, a light intensity signal quantity isolation pre-following circuit, a light intensity signal isolation circuit, a light intensity signal differential amplification circuit and a light intensity signal quantity isolation post-following circuit. A plasma light intensity sensor is arranged in the reactor, and the plasma is sensed in real time by the light intensity sensor and the variables related to the plasma characteristics are obtained, and converted into a plasma intensity compensation signal quantity, which is sent to the power supply end after isolation. The power supply end performs compensation output according to the compensation signal quantity, thereby completing the entire plasma intensity compensation process.

2. The plasma intensity compensation circuit based on load characteristics according to claim 1, characterized in that: The light intensity collection circuit includes an integrated operational amplifier module U1.1, an external port plasma+, and an external port plasma-. The two external ports plasma+ and plasma- are used to connect a passive plasma light intensity sensor, sampling resistors (R1~R5) and an output resistor R6. In the light intensity collection circuit, after the series voltage division of the sampling resistors R1 and R2, a DC voltage signal negatively correlated with the plasma light intensity is obtained.

3. The plasma intensity compensation circuit based on load characteristics according to claim 1, characterized in that: The light intensity signal isolation pre-follower circuit comprises an integrated operational amplifier module U1.2, filter resistors (R7, R8), and filter capacitors (C1, C2). After the light intensity signal is converted into a negatively correlated DC voltage signal, a smooth and real light intensity signal is obtained through impedance transformation and filtering for use by subsequent circuits.

4. The plasma intensity compensation circuit based on load characteristics according to claim 1, characterized in that: The light intensity signal differential amplifier circuit includes an integrated operational amplifier module U2.1, differential amplifier resistors (R9~R12) and an output resistor R13. The light intensity signal differential amplifier circuit restores the light intensity voltage signal of the isolated light intensity signal to obtain an isolated voltage signal that is negatively correlated with the light intensity signal.

5. The plasma intensity compensation circuit based on load characteristics according to claim 1, characterized in that: The light intensity signal isolation follower circuit comprises an integrated operational amplifier module U2.2, a filter resistor R14 and a filter capacitor C3. In the light intensity signal isolation follower circuit, after obtaining the isolated plasma light intensity voltage signal, impedance matching and filtering are performed.

6. The plasma intensity compensation circuit based on load characteristics according to claim 2, characterized in that: In the light intensity collection circuit, port 3 of the integrated operational amplifier module U1.1 is connected to one end of the sampling resistor R5, the other end of the sampling resistor R5 is connected to one end of the sampling resistor R1, and is connected to the positive end of the plasma light intensity sensor; the other end of the sampling resistor R1 is connected to the positive power supply terminal VCC; port 2 of the integrated operational amplifier module U1.1 is connected to one end of the sampling resistor R3, and is connected to one end of the sampling resistor R4, the other end of the sampling resistor R3 is connected to the negative power supply terminal GND, and the other end of the sampling resistor R4 is connected to port 7 of the integrated operational amplifier module U1.1; port 8 of the integrated operational amplifier module U1.1 is connected to the positive power supply terminal VCC, and port 4 of the integrated operational amplifier module U1.1 is connected to the negative power supply terminal GND; one end of the sampling resistor R2 is connected to the negative power supply terminal GND, and the other end is connected to the negative end of the plasma light intensity sensor; one end of the output resistor R6 is connected to port 7 of the integrated operational amplifier module U1.

1.

7. The plasma intensity compensation circuit based on load characteristics according to claim 3, characterized in that: In the light intensity signal isolation front follower circuit, port 5 of the integrated operational amplifier module U1.2 is connected to the other end of the output resistor R6; port 6 of the integrated operational amplifier module U1.2 is connected to port 7 of the integrated operational amplifier module U1.2; one end of the filter resistor R7 is connected to port 7 of the integrated operational amplifier module U1.2, and the other end is connected to one end of the filter capacitor C1 and to one end of the filter resistor R8; the other end of the filter resistor R8 is connected to one end of the filter capacitor C2.

8. The plasma intensity compensation circuit based on load characteristics according to claim 1, characterized in that: In the light intensity signal isolation circuit, ports 1-4 of the DC voltage isolation conversion integrated chip U3 are the isolation front end, and ports 5-8 are the isolation back end; the isolation front and back ends are powered by independent voltage sources, and port 2 of the DC voltage isolation conversion integrated chip U3 is connected to the filter capacitor C2; ports 7 and 6 of the DC voltage isolation conversion integrated chip U3 output the isolation voltage in a differential form.

9. The plasma intensity compensation circuit based on load characteristics according to claim 4, characterized in that: One end of the differential amplifier resistor R9 in the light intensity signal differential amplifier circuit is connected to port 7 of the DC voltage isolation conversion integrated chip U3, and the other end is connected to port 3 of the integrated operational amplifier module U2.1, and is connected to one end of the differential amplifier resistor R12; one end of the differential amplifier resistor R10 is connected to port 6 of the DC voltage isolation conversion integrated chip U3, and the other end is connected to port 2 of the integrated operational amplifier module U2.1, and is connected to one end of the differential amplifier resistor R11, and the other end of the differential amplifier resistor R11 is connected to port 1 of the integrated operational amplifier module U2.1, and is connected to one end of the output resistor R13.

10. The plasma intensity compensation circuit based on load characteristics according to claim 5, characterized in that: Port 5 of the integrated operational amplifier module U2.2 is connected to the other end of the output resistor R13; port 7 of the integrated operational amplifier module U2.2 is connected to port 6 of the integrated operational amplifier module U2.2, and is connected to one end of the filter resistor R14, the other end of the filter resistor R14 is connected to the filter capacitor C3, and is connected to the external output port plasma-sense.

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