A miniaturized cryogenic plasma generator and system with closed-loop control

Abstract

This invention discloses a miniaturized low-temperature plasma generator and system with closed-loop control, comprising a plasma generating unit including a high-voltage electrode, an insulating dielectric layer, and a grounding electrode; a temperature detection unit integrated on the working surface of the plasma generating unit, including a non-contact infrared temperature sensor or a flexible thermistor / thermocouple array, wherein the probe of the non-contact infrared temperature sensor faces the interface between the plasma and the working area, for real-time acquisition of temperature data of the working area, and multiple thermistors / thermocouples form a distributed temperature measurement network to obtain a three-dimensional temperature distribution map of the working area in real time; and a closed-loop control unit including a control circuit and a high-voltage power supply module, wherein the control circuit includes a microcontroller, the microcontroller receives the real-time temperature signal fed back by the temperature detection unit, compares it with a preset safety threshold and target temperature, and dynamically adjusts the output parameters of the power supply module according to a preset control algorithm.

Description

Technical Field

[0001] This invention relates to the field of technology, specifically to a miniaturized low-temperature plasma generator and system with closed-loop control. Background Technology

[0002] Plasma technology, especially low-temperature atmospheric pressure plasma generated based on the dielectric barrier discharge (DBD) principle, has shown broad application prospects in the fields of biomedicine, skin treatment, wound healing, and cosmetic care in recent years. Unlike traditional electrosurgical equipment or high-temperature plasmas (such as electrocoagulation and electrocautery), DBD plasma generators can generate non-equilibrium plasma rich in reactive particles (such as reactive oxygen species (ROS) and reactive nitrogen species (RNS)) on the human body surface. Its macroscopic gas temperature can be close to room temperature, thereby achieving sterilization, promoting cell regeneration, and stimulating collagen remodeling while avoiding thermal damage to healthy tissues.

[0003] However, existing handheld or stationary plasma generators have significant technical drawbacks. First, although the "gas temperature" of plasma is low, during the discharge process, due to dielectric loss of the dielectric layer (ceramic or quartz), Joule heating of the electrodes, and bombardment of the surface by high-energy ions, the local surface temperature of the plasma jet or discharge head and the working area may still increase significantly with prolonged working time. Without real-time monitoring and control, this can easily lead to low-temperature burns or localized thermal stress reactions.

[0004] Secondly, most existing equipment uses an open-loop control mode. Operators can only judge the discharge intensity and processing time based on experience, and the equipment itself cannot dynamically adjust the discharge power or duty cycle according to real-time changes in the temperature of the working area. Due to the drastically different heat accumulation effects in the working areas, the equipment cannot achieve dynamic adjustment, which greatly affects the working efficiency and safety of the equipment.

[0005] Therefore, developing a plasma generator that integrates real-time body surface temperature detection and dynamically adjusts the discharge power through a closed-loop feedback mechanism is of great significance for improving equipment safety and ensuring equipment functionality. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a miniaturized low-temperature plasma generator and system with closed-loop control, which solves the technical problem that existing low-temperature plasma equipment lacks the ability to monitor and adaptively adjust the working area when it acts on the working area, and is prone to thermal damage or inconsistent treatment effects due to heat accumulation.

[0007] This invention is achieved through the following technical solution: A miniaturized cryogenic plasma generator and system with closed-loop control according to this invention, comprising: Plasma generating unit: including high-voltage electrode, insulating dielectric layer and ground electrode, this unit is used to receive excitation from high-frequency high-voltage power supply and generate low-temperature plasma at discharge gap or jet outlet; Temperature detection unit: Integrated into the working end face of the plasma generation unit, including a non-contact infrared temperature sensor or a flexible thermistor / thermocouple array. The probe of the non-contact infrared temperature sensor faces the interface between the plasma and the working area, and is used to collect temperature data of the working area in real time. Multiple thermistors / thermocouples form a distributed temperature measurement network to obtain a three-dimensional temperature distribution map of the working area in real time. Closed-loop control unit: includes control circuit and high-voltage power supply module. The control circuit includes microcontroller. The microcontroller receives real-time temperature signal feedback from temperature detection unit, compares it with preset safety threshold and target temperature, and dynamically adjusts the output parameters of power supply module according to preset control algorithm.

[0008] Further technical solutions include safety thresholds ranging from 38℃ to 42℃.

[0009] Further technical solutions include PID control algorithms.

[0010] When the equipment starts up and performs plasma treatment on the working area, the temperature detection unit captures the temperature changes in the working area in real time at a sampling frequency of milliseconds. This temperature signal is then input to the closed-loop control unit after analog-to-digital conversion.

[0011] The microcontroller dynamically adjusts the high-voltage power supply module according to a preset temperature-power mapping relationship: When the detected temperature of the working area is lower than the set lower limit, the controller maintains or increases the discharge power to ensure the effective generation of active particles and the exertion of biological effects. When the temperature approaches or exceeds the set safety limit, the microcontroller promptly reduces the drive voltage, decreases the duty cycle, or triggers an intermittent discharge mode until the temperature drops back to a safe range. If an abnormal temperature spike is detected, the system will execute a hardware-level emergency power-off protection; at the same time, a warning message will be issued and a red light will flash rapidly.

[0012] In a further technical solution, when setting up an infrared temperature sensor, the insulating dielectric layer includes a quartz glass tube, a high-voltage electrode is fixed on the central axis of the quartz glass tube, copper foil is wrapped around the outer wall of the quartz glass tube as a grounding electrode, and a jet-like low-temperature plasma plume is generated at the outlet of the quartz glass tube to form a plasma region.

[0013] In a further technical solution, the infrared temperature sensor is provided with a grounded metal shield, and the grounding end of the shield is connected to the ground wire of the control circuit at a single point.

[0014] A further technical solution is that the output terminal of the infrared temperature sensor is connected to I... 2 The C bus is connected to the I / O port of the microcontroller, the PWM output pin of the microcontroller is connected to the control terminal of the high-voltage power supply module, and the output terminal of the high-voltage power supply module is connected to the high-voltage electrode.

[0015] A further technical solution also includes a ring-shaped grounding electrode, with the infrared temperature sensor installed at the center of the ring-shaped grounding electrode. The infrared temperature sensor is grounded to the microcontroller side at one end via a shielding wire. Micropores are provided at the bottom of the insulating dielectric layer, and the micropores are filled with thermally conductive adhesive.

[0016] A closed-loop control method for a low-temperature plasma generator that uses an infrared temperature sensor for temperature measurement is as follows: S1, Parameter Preset: Users can set the operating mode and maximum working time via buttons; S2, Real-time Acquisition: The microcontroller reads data from the infrared temperature sensor at a sampling period of 50ms, and processes it through a digital filtering algorithm to obtain the real-time temperature T of the working area. real ; S3, PID control: The microcontroller executes the PID control algorithm, adjusting T... real With the set temperature T set The difference is used as the input, and the output controls the duty cycle of the PWM wave. When T real <T set At -1℃, the duty cycle increases at a rate of 5% per cycle until full power is reached; When T real >T set At +1℃, the duty cycle decreases at a rate of 10% per cycle until the temperature drops. When T real When the temperature exceeds 45℃, the microcontroller immediately blocks the PWM output, causing the high-voltage power supply module to stop working, and emits a rapid alarm sound through the buzzer, while the screen displays alarm information.

[0017] In a further technical solution, when setting up a flexible thermistor / thermocouple array, the insulating dielectric layer includes a ceramic substrate, the back of which is printed with a high-voltage electrode, the front of which is covered with the insulating dielectric layer, and the grounding electrode is embedded in the insulating dielectric layer or attached to the back of the ceramic substrate by thermally conductive adhesive.

[0018] In a further technical solution, the high-voltage electrode is made of silver-palladium alloy, the insulating dielectric layer includes insulating thermally conductive silicone, the grounding electrode includes a metal mesh embedded in the surface of the insulating thermally conductive silicone, the ceramic substrate includes alumina, and the flexible thermistor / thermocouple array includes an NTC thermistor array based on a polyimide substrate.

[0019] In a further technical solution, micropores are provided on the insulating dielectric layer, and the micropores are filled with thermally conductive adhesive.

[0020] A closed-loop control method for a low-temperature plasma generator utilizing a flexible thermistor / thermocouple array is as follows: S1, Signal Processing: Each thermistor / thermocouple is connected to the microcontroller's multi-channel analog-to-digital converter via a voltage divider circuit, and the microcontroller quickly scans all temperature measurement points; S2, Real-time Acquisition: The microcontroller reads thermistor / thermocouple data at a sampling period of 50ms, and processes the data through a digital filtering algorithm to obtain the real-time temperature T of the working area. real ; S3, PID control: The microcontroller executes the PID control algorithm, adjusting T... real With the set temperature T set The difference is used as the input, and the output controls the duty cycle of the PWM wave. When T real <T set At -1℃, the duty cycle increases at a rate of 5% per cycle until full power is reached; When T real >T set At +1℃, the duty cycle decreases at a rate of 10% per cycle until the temperature drops. S4, Regional Temperature Equalization: When the microcontroller detects that the temperature of a certain local area is significantly higher than that of the edge area, it determines that the equipment is not evenly attached or that the heat accumulation in the local working area is too fast. The microcontroller also reduces the micro-discharge density in the corresponding area by changing the phase or triggering mode of the high voltage power supply. S5, Abnormal Detection: If the temperature at any temperature measuring point exceeds the rated temperature, or the temperature difference between any two points exceeds the specified temperature, the system judges it as a device malfunction or a serious fit abnormality, immediately cuts off the high-voltage output, and displays a fault code.

[0021] A further technical solution has a rated temperature of 46℃ and a specified temperature of 8℃.

[0022] The specific algorithm of a closed-loop control unit for a low-temperature plasma generator is as follows: S1, Adaptive reference calibration during startup: S1.1, Microcontroller reads the initial value T from the temperature detection unit. init S1.2, if T init The equipment will trigger an audible and visual alarm if the temperature drops below 32℃; S1.3, if T init Between 32℃ and 38℃, the equipment uses this value as the base temperature T. base And set the target temperature adjustment to T. base +ΔT, where ΔT is the temperature rise value set by the user; S2, Dynamic Power Limiting Algorithm: S2.1, Define the maximum allowable power Pmax as related to the temperature rise rate dT / dt; S2.2, If dT / dt > 2℃ / s, immediately limit Pmax to 60% of the current power and continue until the temperature rise rate drops to a safe range; S2.3, If the cumulative power output exceeds the preset safe dose threshold during operation, the system will automatically terminate.

[0023] The beneficial effects of the present invention are as follows: First, the closed-loop control miniaturized low-temperature plasma generator and system of the present invention, through the integrated layout of the coaxial DBD jet structure and infrared temperature sensor, the PID closed-loop control algorithm of the MCU, adaptive reference calibration and dynamic power limiting, achieves the technical effects of real-time temperature control, reliable safety protection, strong individual adaptability and good electromagnetic compatibility, effectively overcoming the defects of existing plasma treatment devices such as lack of temperature feedback, inconsistent effects and poor anti-interference ability.

[0024] 2. The plasma generation unit adopts a coaxial dielectric barrier discharge jet structure. The high-voltage electrode is built into the central axis of the quartz glass tube, and the outer wall is wrapped with copper foil as a grounding electrode. A jet-shaped low-temperature plasma plume is generated at the outlet of the quartz glass tube. The structure is compact, the discharge is stable, and it is easy to operate by hand. The temperature detection unit uses an infrared temperature sensor fixed to the end face of the working head. The photosensitive window is at an angle of 10° to 15° with the axis of the jet outlet. The focal point coincides with the working area, realizing non-contact real-time detection of the temperature of the working area and avoiding the risk of breakdown caused by the sensor directly contacting the discharge area.

[0025] 3. The surface of the infrared temperature sensor probe is flush with or slightly recessed inward by 1 to 2 millimeters, and a grounded metal shield is provided. The grounding terminal of the shield is connected to the ground wire of the control circuit at a single point, which effectively isolates the electromagnetic interference caused by high-frequency high-voltage discharge to the sensor, improves the accuracy and stability of temperature detection, and extends the service life of the sensor.

[0026] IV. The control circuit is based on a microcontroller and uses I / O pins. 2 The C-bus receives data from the infrared temperature sensor, processes it through digital filtering, and then executes a PID control algorithm. The difference between the real-time temperature and the set temperature is used as the input, and the output PWM wave duty cycle is used to adjust the output power of the high-voltage power supply module, thus achieving closed-loop precise control of the treatment temperature. When the real-time temperature is 1°C lower than the set temperature, the duty cycle increases; when it is 1°C higher than the set temperature, the duty cycle decreases. The response is rapid, ensuring that the temperature of the treatment area is always maintained within the set range.

[0027] Fifth, the system is set with an absolute safety threshold. When the real-time temperature exceeds 45℃, the microcontroller immediately blocks the PWM output, the high-voltage power supply module stops working, and a rapid alarm sound is emitted through the buzzer. The alarm information is displayed on the screen, which improves the safety of equipment use.

[0028] VI. During the startup phase, adaptive benchmark calibration is adopted. The bonding status is automatically determined based on the initial temperature value of the sensor, and the initial value is used as the base temperature within the range of 32℃ to 38℃. The target temperature is set as the base temperature plus the temperature rise value set by the user. The relative temperature rise control mode is adopted, which expands the scope of application and improves the individual adaptability of the treatment effect.

[0029] 7. The control unit is equipped with a dynamic power limiting algorithm. By monitoring the rate of temperature rise, the maximum allowable power is limited to 60% of the current power when the temperature rises too quickly, preventing overshoot caused by PID integral saturation. At the same time, a safe dose threshold for cumulative power output is set. If the threshold is exceeded, the system will automatically terminate and issue a warning, thus avoiding overtreatment and ensuring safe use.

[0030] 8. For large-area flat-plate structures, a flexible thermistor array is used to form a distributed temperature measurement network, which can acquire a three-dimensional temperature distribution map of the working area in real time. When the temperature of a local area is detected to be significantly higher than that of the edge area, the micro-discharge density of the corresponding area is reduced by changing the phase or triggering mode of the high-voltage power supply, thereby realizing fine spatial temperature regulation and ensuring temperature uniformity during large-area processing.

[0031] 9. Electromagnetic compatibility design adopts differential signal transmission, opto-isolation and discharge synchronization suppression algorithm. The microcontroller pauses temperature sampling within 20 microseconds after triggering the high voltage pulse to avoid the interference window, ensuring the authenticity of the collected data and improving the reliability of the system in strong electromagnetic environment. Attached Figure Description

[0032] For ease of explanation, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the device structure according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the device structure according to Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the device structure when the thermally conductive adhesive is bonded to the back of the ceramic substrate in Embodiment 2 of the present invention; Figure 4 This is a schematic diagram of the system workflow of Embodiment 3 of the present invention; Figure 5 This is a schematic diagram of an infrared temperature sensor installed at the center of a ring-shaped grounding electrode. Figure 6 This is a schematic diagram of the structure of a contact sensor with micropores created in the insulating dielectric layer. Detailed Implementation

[0034] like Figures 1-6As shown, the present invention will be described in detail. For ease of description, the directions mentioned below are defined as follows: the directions of up, down, left, right, front, and back mentioned below are the same as... Figure 1 The directions of the projection relationship are consistent in all directions: up, down, left, right, front, and back.

[0035] Example 1: A miniaturized low-temperature plasma generator and system with closed-loop control according to the present invention includes an insulating shell, inside which a high-voltage power supply module and a control circuit are housed, and a working head is provided at the front end of the insulating shell, the working head including a plasma generating unit and a temperature detection unit.

[0036] Advantageously, the plasma generation unit adopts a coaxial dielectric barrier discharge (DBD) jet structure; The high-voltage electrode is a stainless steel needle with a diameter of 1 mm, which is embedded in the central axis of a quartz glass tube (dielectric layer); The outer wall of the quartz glass tube is wrapped with copper foil as a grounding electrode, and the front end of the quartz glass tube extends 5mm beyond the end face of the working head to form a plasma jet outlet.

[0037] During operation, a working gas (such as a mixture of helium or argon and air) is introduced into the quartz glass tube. The high-voltage power supply module applies a high-frequency, high-voltage sine wave (frequency 20kHz, peak voltage 5-10kV) to the high-voltage electrode, generating a jet-like low-temperature plasma plume at the outlet of the quartz glass tube to form a plasma region that acts on the working area.

[0038] Advantageously, the temperature detection unit employs an infrared temperature sensor (e.g., MLX90614 or other non-contact infrared temperature measurement chip). The infrared temperature sensor is fixed to the end face of the working head, located on one side of the plasma jet outlet. Its photosensitive window forms an angle of 10° to 15° with the axis of the jet outlet, and the focal point coincides with the working area. The surface of the infrared temperature sensor probe is flush with or slightly recessed inward by 1 to 2 mm to prevent high voltage discharge from causing breakdown or electromagnetic interference to the sensor. A grounded metal shield is installed between the infrared temperature sensor and the plasma zone, and the grounding terminal of the shield is connected to the ground wire of the control circuit at a single point.

[0039] Advantageously, the control circuitry includes a microcontroller (MCU, e.g., STM32F103), a high-voltage power supply module, a signal modulation circuit, and a display / button interaction module.

[0040] Beneficially, the signal flow is as follows: the output of the infrared temperature sensor is connected to I... 2 The C bus is connected to the MCU's I / O port; The PWM output pin of the MCU is connected to the control terminal of the high-voltage power supply module; The output terminal of the high-voltage power supply module is connected to the discharge electrode of the DBD unit.

[0041] Beneficially, the closed-loop control logic includes: Preset parameters: Users can set the operating mode (such as "Repair Mode" target temperature 38℃, "Tightening Mode" target temperature 42℃) and the maximum working time (default 10 minutes) by pressing the buttons. Real-time data acquisition: The MCU reads data from the infrared temperature sensor at a sampling period of 50ms, and processes it through a digital filtering algorithm (such as moving average filtering) to obtain the real-time temperature T of the working area. real ; PID control: The MCU executes the PID control algorithm, adjusting T... real With the set temperature T set The difference is used as the input quantity, and the output quantity controls the duty cycle of the PWM wave (range of 0%-100%), thereby adjusting the output power of the high voltage power supply module. When T real <T set At -1℃, the duty cycle increases at a rate of 5% per cycle until full power is reached; When T real >T set At +1℃, the duty cycle decreases at a rate of 10% per cycle until the temperature drops. When T real When the temperature exceeds 45℃ (absolute safety threshold), the MCU immediately blocks the PWM output, causing the high-voltage power supply module to stop working, and emits a rapid alarm sound through the buzzer, while the screen displays alarm information.

[0042] In this embodiment, the workflow is as follows: The user holds the device, aligns the working head with the area to be processed, and presses the start button. The device first performs a pre-discharge at low power (20% duty cycle), and the infrared temperature sensor reads the initial temperature of the area to be processed as a reference. Subsequently, the device automatically increases to the target power. During the operation of the device, the user slowly moves the working head. If the movement speed is too slow, causing the local temperature to rise rapidly, the controller responds within 100ms and reduces the power; if the movement speed is too fast, causing the temperature to drop, the controller appropriately increases the power to ensure that the temperature of the processed area is always maintained within the set range.

[0043] Example 2: A large-area planar plasma generator based on a contact thermistor array, comprising: Control circuitry: includes a microcontroller (MCU) and a multi-channel analog-to-digital converter (ADC); Discharge unit: It adopts a flat-array structure, including a ceramic substrate. The back of the ceramic substrate is printed with silver-palladium alloy as a high-voltage electrode. The front of the substrate (the side facing the working area) is covered with a 0.5mm thick insulating and thermally conductive silicone as a dielectric layer for direct contact and discharge with the working area. The grounding electrode is a metal mesh embedded in the surface of the insulating and thermally conductive silicone. During operation, a high-frequency high-voltage pulse is applied to the high-voltage electrode, which generates a large area of ​​uniform filamentary or glow discharge in the tiny air gap between the silicone surface and the working area. Temperature detection unit: includes a flexible thermistor array, which is attached to the inside of the insulating thermally conductive silicone layer, or attached to the back of the ceramic substrate by thermally conductive adhesive. Multiple thermistors form a distributed temperature measurement network, which can acquire a three-dimensional temperature distribution map of the working area in real time.

[0044] Advantageously, the ceramic substrate can be selected as alumina with a dielectric constant of 9.5 and a thickness of 1 mm.

[0045] Advantageously, the high-frequency high-voltage pulse has a frequency of 100kHz and a pulse rise time of 200ns.

[0046] Advantageously, the flexible thermistor array can be an NTC thermistor array based on a polyimide substrate, with a size of 10×10 array and a spacing of 5mm.

[0047] Advantageously, the flexible thermistor array is attached to the inner side of the insulating thermally conductive silicone layer, that is, close to the discharge region but located on the safe side of the dielectric layer.

[0048] Its circuit connections and control system include: Signal processing: Each thermistor is connected to the MCU's multi-channel analog-to-digital converter (ADC) through a voltage divider circuit. The MCU uses multiplexing technology to quickly scan all temperature measurement points. Safety protection mechanism: In addition to the PID overall power regulation similar to Example 1, this example adds a regional temperature equalization function; when the MCU detects that the temperature of a certain local area (such as the central area) is significantly higher than that of the edge area (temperature difference exceeds 3°C), it is determined that the equipment is not evenly attached or the local working area is too hot. At this time, the MCU does not simply reduce the total power, but reduces the micro-discharge density corresponding to the area by changing the phase or trigger mode of the high voltage power supply (in the array electrode design, this can be achieved by independently controlling the sub-electrodes), thereby achieving fine spatial temperature regulation. Anomaly detection: If the temperature at any measuring point exceeds 46℃, or the temperature difference between any two points exceeds 8℃, the system will determine that the equipment is faulty or there is a serious fit abnormality, immediately cut off the high voltage output, and display a fault code.

[0049] Example 3, based on any one of Examples 1 to 2, further defines the following: the specific algorithm of the closed-loop control unit is further defined: Adaptive benchmark calibration during startup: S1, the MCU reads the initial value T from the temperature sensor. init ; S2, if T init If the temperature is below 32℃ (possibly due to the sensor not being in contact with the work area or the ambient temperature being too low), the equipment will display an audible and visual alarm (frequency 1Hz) prompting "Please attach the work area". S3, if T init Between 32℃ and 38℃, the equipment uses this value as the base temperature T. base And set the target temperature adjustment to T. base +ΔT, where ΔT is the temperature rise value set by the user (e.g., 3-5℃). This relative temperature rise control mode is better able to adapt to the differences in different processing areas than absolute temperature control.

[0050] Dynamic power limiting algorithm: To prevent overshoot caused by PID integral saturation, a dynamic power limiter is set in the control unit. S1 defines the maximum allowable power P. max Related to the rate of temperature rise dT / dt; S2, if dT / dt > 2℃ / s (temperature rise is too rapid), immediately reduce P max Limit to 60% of current power and continue until the heating rate drops to a safe range; S3. If the cumulative power output exceeds the preset safe dose threshold (e.g., 30kJ) during operation, the system will automatically terminate and display the message "Today's maximum workload has been achieved".

[0051] Example 4, based on Example 1 or 3, further specifies the following: Electromagnetic compatibility design: Since the plasma generator produces a high-frequency, high-voltage electric field during operation, it can easily interfere with the high-impedance temperature sensor signal. Therefore, this solution adopts the following anti-interference measures in its implementation: S1, Differential signal transmission: For analog signal sensors, differential amplifier circuits are used for transmission to improve the common-mode rejection ratio; S2, Opto-isolation: The control signals of the control circuit and the high-voltage power supply module are isolated by optocouplers to ensure electrical isolation between the high-voltage and low-voltage parts; S3, Software Filtering: The "Discharge Synchronization Suppression" algorithm is embedded in the sampling program of the control circuit. Since discharge interference is usually concentrated on the rising and falling edges of the high voltage pulse, the MCU pauses temperature sampling within 20μs after triggering the high voltage pulse to avoid the interference window and ensure the authenticity of the collected data.

[0052] Example 5, based on Example 1, 2, 3, or 4, further defines the following: To facilitate the integration of a high-voltage electrode and an infrared temperature sensor within a confined treatment head, and to ensure that the infrared temperature sensor is protected from damage by the high-voltage electric field, this solution provides a preferred structural layout: Coplanar layout: The infrared temperature sensor is mounted at the center of the ring-shaped grounding electrode, utilizing the equipotential region formed by the grounding electrode to shield against external electric fields. The sensor signal lines are shielded, and the shielding layer is grounded only at one end on the controller side.

[0053] Thermal conduction channel design: For contact sensors, micropores (diameter less than 0.5mm, which does not affect the overall withstand voltage of the dielectric) are opened on the insulating dielectric layer (ceramic). The pores are filled with a high thermal conductivity insulating material (such as boron nitride thermal conductive adhesive) to conduct the heat on the surface of the processing area to the temperature sensor on the back, avoiding direct exposure of the sensor to the discharge area.

[0054] Through the above specific implementation methods, the present invention achieves real-time and accurate detection and closed-loop control of the temperature of the plasma acting on the work area, effectively solving the problem of inconsistent burn risk and effect caused by the lack of temperature feedback in the prior art.

[0055] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived without creative effort should be included within the scope of protection of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A miniaturized low-temperature plasma generator with closed-loop control, comprising a plasma generation unit, a temperature detection unit, and a closed-loop control unit, characterized in that: Plasma generating unit: including high-voltage electrode, insulating dielectric layer and ground electrode, this unit is used to receive excitation from high-frequency high-voltage power supply and generate low-temperature plasma at discharge gap or jet outlet; Temperature detection unit: Integrated into the working end face of the plasma generation unit, including a non-contact infrared temperature sensor or a flexible thermistor / thermocouple array. The probe of the non-contact infrared temperature sensor faces the interface between the plasma and the working area, and is used to collect temperature data of the working area in real time. Multiple thermistors / thermocouples form a distributed temperature measurement network to obtain a three-dimensional temperature distribution map of the working area in real time. Closed-loop control unit: includes control circuit and high-voltage power supply module. The control circuit includes microcontroller. The microcontroller receives real-time temperature signal feedback from temperature detection unit, compares it with preset safety threshold and target temperature, and dynamically adjusts the output parameters of power supply module according to preset control algorithm.

2. The miniaturized cryogenic plasma generator with closed-loop control according to claim 1, characterized in that: When setting up an infrared temperature sensor, the insulating dielectric layer includes a quartz glass tube, a high-voltage electrode is fixed on the central axis of the quartz glass tube, copper foil is wrapped around the outer wall of the quartz glass tube as a grounding electrode, and a plasma region is formed at the outlet of the quartz glass tube.

3. A miniaturized cryogenic plasma generator with closed-loop control according to claim 2, characterized in that: The infrared temperature sensor is equipped with a grounded metal shield, and the grounding terminal of the shield is connected to the ground wire of the control circuit at a single point.

4. A miniaturized cryogenic plasma generator with closed-loop control according to claim 2, characterized in that: It also includes a ring-shaped grounding electrode, the infrared temperature sensor is installed at the center of the ring-shaped grounding electrode, the infrared temperature sensor is grounded to the microcontroller side at one end through a shielding wire, and the bottom of the insulating dielectric layer is provided with micropores, which are filled with thermally conductive adhesive.

5. A closed-loop control method for infrared temperature sensor measurement in a miniaturized low-temperature plasma generator with closed-loop control according to any one of claims 1-4, characterized in that: S1, Parameter Preset: Users can set the operating mode and maximum working time via buttons; S2, Real-time Acquisition: The microcontroller reads data from the infrared temperature sensor at a sampling period of 50ms, and processes it through a digital filtering algorithm to obtain the real-time temperature T of the working area. real ; S3, PID control: The microcontroller executes the PID control algorithm, adjusting T... real With the set temperature T set The difference is used as the input, and the output controls the duty cycle of the PWM wave. When T real <T set At -1℃, the duty cycle increases at a rate of 5% per cycle until full power is reached; When T real >T set At +1℃, the duty cycle decreases at a rate of 10% per cycle until the temperature drops. When T real When the temperature exceeds 45℃, the microcontroller immediately blocks the PWM output, causing the high-voltage power supply module to stop working, and emits a rapid alarm sound through the buzzer, while the screen displays alarm information.

6. A miniaturized cryogenic plasma generator with closed-loop control according to claim 1, characterized in that: When setting up a flexible thermistor / thermocouple array, the insulating dielectric layer includes a ceramic substrate, the back of which is printed with a high-voltage electrode, the front of which is covered with the insulating dielectric layer, and the grounding electrode is embedded in the insulating dielectric layer or attached to the back of the ceramic substrate by thermally conductive adhesive.

7. A miniaturized cryogenic plasma generator with closed-loop control according to claim 6, characterized in that: The high-voltage electrode is made of silver-palladium alloy, the insulating dielectric layer includes insulating thermally conductive silicone, the grounding electrode includes a metal mesh embedded in the surface of the insulating thermally conductive silicone, the ceramic substrate includes alumina, and the flexible thermistor / thermocouple array includes an NTC thermistor array based on a polyimide substrate.

8. A miniaturized cryogenic plasma generator with closed-loop control according to claim 7, characterized in that: The insulating dielectric layer has micropores, which are filled with thermally conductive adhesive.

9. A closed-loop control method for temperature measurement using a flexible thermistor / thermocouple array in a miniaturized cryogenic plasma generator according to claim 6, 7, or 8, characterized in that: S1, Signal Processing: Each thermistor / thermocouple is connected to the microcontroller's multi-channel analog-to-digital converter via a voltage divider circuit, and the microcontroller quickly scans all temperature measurement points; S2, Real-time Acquisition: The microcontroller reads thermistor / thermocouple data at a sampling period of 50ms, and processes the data through a digital filtering algorithm to obtain the real-time temperature T of the working area. real ; S3, PID control: The microcontroller executes the PID control algorithm, adjusting T... real With the set temperature T set The difference is used as the input, and the output controls the duty cycle of the PWM wave. When T real <T set At -1℃, the duty cycle increases at a rate of 5% per cycle until full power is reached; When T real >T set At +1℃, the duty cycle decreases at a rate of 10% per cycle until the temperature drops. S4, Regional Temperature Equalization: When the microcontroller detects that the temperature of a certain local area is significantly higher than that of the edge area, it determines that the equipment is not evenly attached or that the heat accumulation in the local working area is too fast. The microcontroller also reduces the micro-discharge density in the corresponding area by changing the phase or triggering mode of the high voltage power supply. S5, Abnormal Detection: If the temperature at any temperature measuring point exceeds the rated temperature, or the temperature difference between any two points exceeds the specified temperature, the system judges it as a device malfunction or a serious fit abnormality, immediately cuts off the high-voltage output, and displays a fault code.

10. The closed-loop control algorithm for a miniaturized cryogenic plasma generator according to claim 1, characterized in that: S1, Adaptive reference calibration during startup: S1.1, Microcontroller reads the initial value T from the temperature detection unit. init S1.2, if T init The equipment will trigger an audible and visual alarm if the temperature drops below 32℃; S1.3, if T init Between 32℃ and 38℃, the equipment uses this value as the base temperature T. base And set the target temperature adjustment to T. base +ΔT, where ΔT is the temperature rise value set by the user; S2, Dynamic Power Limiting Algorithm: S2.1, Define the maximum allowable power Pmax as related to the temperature rise rate dT / dt; S2.2, If dT / dt > 2℃ / s, immediately limit Pmax to 60% of the current power and continue until the temperature rise rate drops to a safe range; S2.3, If the cumulative power output exceeds the preset safe dose threshold during operation, the system will automatically terminate.

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