A surface area plasma air disinfection system and method

Abstract

This invention provides a surface-source plasma air disinfection system and method, belonging to the field of air purification technology. The system includes: a flat, sandwich-type dielectric barrier discharge unit, which has sequentially stacked perforated mesh high-voltage electrodes, a dielectric barrier layer, and a fully covered flat-plate grounding electrode; and a pulse power supply, outputting a pulse voltage with a working frequency of 15-20kHz and a peak voltage of 3-6kV. This invention achieves uniform discharge, low energy consumption, controllable byproducts, and high dynamic processing efficiency through the coordinated design of electrode structure, electrical parameters, and airflow parameters.

Description

Technical Field

[0001] This invention relates to the field of air purification technology, and in particular to a surface source plasma air disinfection system and method. Background Technology

[0002] Currently, airborne pathogens are a major cause of respiratory diseases and cross-infection, making continuous and effective disinfection and purification of air in enclosed environments such as indoor spaces crucial. Traditional air disinfection technologies, such as ultraviolet irradiation, chemical spraying, or physical filtration, have limitations, including blind spots, potential chemical residues, ineffective virus inactivation, and filters that can become secondary sources of contamination.

[0003] As an emerging air disinfection technology, dielectric barrier discharge technology is considered to have great application prospects due to its advantages such as broad-spectrum sterilization and no chemical residue. Existing technologies already include air purification systems that utilize the dielectric barrier discharge principle. For example, some solutions employ discharge units with a planar electrode structure and are driven by a pulsed power supply, guiding airflow through gas guide plates.

[0004] However, existing technologies generally suffer from a core challenge: the failure to effectively optimize the system's structural, electrical, and airflow parameters in a coordinated manner. This often leads to difficulties in balancing energy consumption, disinfection efficiency, and safety in practical applications. For example, increasing discharge power to achieve high disinfection efficiency usually results in a sharp increase in energy consumption and excessive generation of harmful byproducts such as ozone and nitrogen oxides, posing safety hazards. Conversely, reducing power simply to decrease energy consumption and byproducts may lead to insufficient plasma activity, significantly reducing the disinfection effect. Furthermore, existing technologies also lack uniformity and efficiency in handling flowing air, making it difficult to meet the high-efficiency purification requirements in dynamic environments. Summary of the Invention

[0005] The purpose of this invention is to provide a surface source plasma air disinfection system and method, which aims to solve the technical problem of the difficulty in balancing energy consumption, disinfection efficiency and safety in the existing dielectric barrier discharge air disinfection technology.

[0006] To achieve the above objectives, the present invention provides a surface-source plasma air sterilization system, comprising: A flat sandwich dielectric barrier discharge unit includes a high-voltage electrode, a dielectric barrier layer, and a ground electrode that are stacked and tightly bonded together in sequence; wherein, the high-voltage electrode is a hollow mesh flat structure, and the ground electrode is a fully covered flat plate structure, the two forming an asymmetric electrode configuration to generate a fully covered surface source plasma on the surface of the dielectric barrier layer. A pulse power supply, electrically connected to the high-voltage electrode and the ground electrode, is configured to output a pulse voltage with an operating frequency of 15-20kHz and a peak voltage of 3-6kV.

[0007] Optionally, the high-voltage electrode is a stainless steel wire mesh electrode with an opening ratio of 70%.

[0008] Optionally, the dielectric barrier layer is a high-purity alumina ceramic sheet with a thickness of 0.8 mm.

[0009] Optionally, it also includes a power closed-loop control system, the power closed-loop control system comprising: A voltage / current sensor electrically connected to the flat sandwich dielectric barrier discharge unit; The microcontroller is configured to receive the detection signal from the voltage / current sensor and adjust the output of the pulse power supply according to a preset target power.

[0010] Optionally, it also includes a safety closed-loop control system, the safety closed-loop control system comprising: An ozone sensor is disposed on the gas outlet side of the flat sandwich dielectric barrier discharge unit. The microcontroller is configured to receive the detection signal from the ozone sensor and adjust the output of the pulse power supply according to a preset safety threshold.

[0011] In a preferred embodiment of the present invention, an ozone sensor is further provided on the outlet side of the flattened sandwich dielectric barrier discharge unit; and the microcontroller is further configured to receive the detection signal of the ozone sensor, and, taking priority of the detection signal of the ozone sensor, adjust the output of the pulse power supply according to a preset target power when the ozone concentration is lower than a preset safety threshold.

[0012] The present invention also provides a method for surface-source plasma air sterilization, which is performed using the above-described surface-source plasma air sterilization system and includes the following steps: The pulse power supply is used to power the flat sandwich dielectric barrier discharge unit, and the operating frequency of the pulse power supply is controlled to be 15-20kHz, and the peak voltage is 3-6kV. The air to be processed is passed through the flattened sandwich dielectric barrier discharge unit at an average flow rate of 0.3-1.2 m / s.

[0013] Optionally, it also includes: The discharge power of the flattened sandwich dielectric barrier discharge unit is monitored in real time, and the output of the pulse power supply is adjusted based on the deviation between the discharge power and the preset target power.

[0014] Optionally, it also includes: The ozone concentration on the outlet side of the flat sandwich dielectric barrier discharge unit is monitored in real time, and when the ozone concentration exceeds a preset safety threshold, the output of the pulse power supply is preferentially reduced.

[0015] Compared with the prior art, the present invention has the following beneficial effects: First, by adopting an asymmetrical combination of hollow mesh high-voltage electrodes and fully covered flat-plate grounding electrodes, a uniform electric field distribution is formed on a macroscopic scale, which can generate uniform and fully covered surface source plasma, solving the problems of uneven disinfection and dead zones caused by traditional point or line discharge.

[0016] Secondly, by coordinating the operating frequency and peak voltage of the pulse power supply within specific low-energy-consumption ranges of 15-20kHz and 3-6kV respectively, and matching a controlled airflow of 0.3-1.2m / s, the energy injection was precisely controlled while ensuring effective air breakdown, thereby reducing the plasma's ignition voltage and sustaining energy consumption, and achieving a reduction in overall energy consumption.

[0017] Furthermore, the specific low-energy discharge mode precisely controls the energy density of a single discharge, effectively suppressing the excessive generation of harmful byproducts such as ozone and nitrogen oxides caused by excessive discharge energy, thereby improving the system's safety in human-machine coexistence environments.

[0018] Finally, the perforated mesh high-voltage electrode structure provides a smooth flow channel for the air to be treated. Combined with the controlled and uniform airflow, it ensures that the active particles in the plasma can have a full and uniform contact reaction with the flowing air, thereby achieving efficient disinfection and purification of the flowing air. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the flattened sandwich dielectric barrier discharge unit provided in an embodiment of the present invention; Figure 2 A schematic diagram of the power closed-loop control system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating an application scenario of the modular purification unit provided in an embodiment of the present invention; Figure 4 A schematic diagram of the ozone concentration feedback control system provided in an embodiment of the present invention; Figure 5 The signaling interaction timing diagram for power closed-loop control provided in the embodiments of the present invention; Figure 6 The signaling interaction timing diagram for the safety closed-loop control provided in the embodiments of the present invention.

[0020] Explanation of reference numerals in the attached figures: 10, high-voltage electrode; 20, dielectric barrier layer; 30, grounding electrode; 200, microcontroller; 210, pulse power supply; 230, voltage / current sensor; 240, feedback signal; 250, control signal; 260, ozone sensor; 270, ozone concentration feedback signal; 300, ventilation duct; 310, modular purification unit; 320, polluted airflow; 330, purified airflow. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] Example 1 This embodiment provides a surface-source plasma air disinfection system and its usage method. The core technical idea lies in achieving efficient, uniform, low-energy-consumption, and safe air disinfection through the coordinated design of the physical structure of the discharge unit, the electrical parameters of the driving power supply, and the airflow parameters of the air to be treated.

[0023] Please see Figure 1 The core of the surface-source plasma air disinfection system provided in this embodiment of the invention is a flat, sandwich-type dielectric barrier discharge unit, which has a compact plate-like structure that is easy to integrate and install. Specifically, the flat, sandwich-type dielectric barrier discharge unit includes a high-voltage electrode 10, a dielectric barrier layer 20, and a grounding electrode 30. The high-voltage electrode 10, the dielectric barrier layer 20, and the grounding electrode 30 are stacked sequentially from top to bottom; to ensure good electric field distribution and structural stability, the layers are tightly fitted together without significant air gaps.

[0024] The high-voltage electrode 10 is located on the top layer and features a hollowed-out mesh-like flat structure. This hollowed-out mesh structure serves two purposes: firstly, it acts as an electrode for applying high voltage, working with the grounding electrode 30 to establish the alternating electric field required for plasma generation; secondly, it provides a clear flow path for the air to be treated, allowing it to pass vertically through the electrode surface into the discharge region. This structure effectively reduces airflow resistance, facilitating the handling of large volumes of air with low pressure drop.

[0025] A dielectric barrier layer 20 is disposed below and in close contact with the high-voltage electrode 10, and is made of one or more insulating materials with high dielectric constant and high dielectric strength (such as quartz glass, high-purity alumina ceramic, or polytetrafluoroethylene). The core function of the dielectric barrier layer 20 is to introduce a capacitive element between the high-voltage electrode 10 and the ground electrode 30. This element is polarized and stores charge under the influence of an electric field, but does not conduct electricity under DC or low-frequency AC. This characteristic effectively prevents the formation of a stable arc discharge between the electrodes, thus ensuring that the discharge is a uniform and diffuse dielectric barrier discharge. Understandably, this discharge mode results in a more uniform energy distribution, avoids localized overheating and electrode damage, and provides the prerequisite for generating a large-area uniform plasma.

[0026] The grounding electrode 30 is located below and closely attached to the dielectric barrier layer 20, serving as the grounding terminal of the entire discharge circuit. Unlike the perforated structure of the high-voltage electrode 10, the grounding electrode 30 is preferably a fully covered flat plate structure. This asymmetrical electrode configuration, consisting of the perforated mesh high-voltage electrode 10 and the fully covered flat plate grounding electrode 30, can form a very uniform electric field distribution on a macroscopic scale. In existing symmetrical electrodes (such as double-perforated mesh electrode structures), the electric field lines cannot be effectively closed in the perforated areas where the mesh holes correspond to each other due to the lack of a grounded metal conductor as an electric field termination carrier, leading to electric field strength attenuation and discharge dead zones. In this invention, when a voltage is applied, the electric field lines originate from the metal mesh of the high-voltage electrode 10, pass through the dielectric barrier layer 20, and then diverge autonomously and project uniformly, terminating without dead angles on the entire surface of the grounding electrode 30 plate below. Even in the area corresponding to the mesh holes of the high-voltage electrode 10, a complete grounding plate below provides the electric field termination condition. This helps to generate a uniform surface-source plasma on the entire surface of the dielectric barrier layer 20, thereby avoiding problems such as uneven discharge, significant edge effects, and sterilization dead zones that are prone to occur in traditional symmetrical electrode or point-to-plate electrode structures.

[0027] To drive the flat, sandwich-type dielectric barrier discharge unit, this system also includes a pulse power supply 210 (the structure of which can be found in [reference]). Figure 2The positive and negative output terminals of the pulse power supply 210 are electrically connected to the high-voltage electrode 10 and the ground electrode 30, respectively. It should be noted that the output parameters of the pulse power supply 210 are specifically and synergistically limited. Specifically, the operating frequency of the pulse voltage output by the pulse power supply 210 is limited to the range of 15-20kHz, and its peak voltage is limited to the range of 3-6kV. It is understandable that the selection of this specific low-frequency, low-voltage parameter range is an optimization result derived from extensive experimental and theoretical analysis. On the one hand, a peak voltage of 3-6kV is sufficient to achieve effective gas breakdown in atmospheric pressure air, generating a sufficient concentration of active particles to ensure disinfection effectiveness; on the other hand, compared to traditional dielectric barrier discharge power supplies that often operate at tens of kilovolts and tens of kilohertz, this parameter range significantly reduces the injection energy of a single micro-discharge and the overall energy consumption. Most importantly, the lower energy density effectively suppresses the occurrence of high-energy side reactions at the source, such as the decomposition and recombination of oxygen molecules into ozone and the reaction of nitrogen and oxygen in the air to generate nitrogen oxides. This keeps the concentration of harmful byproducts at extremely low levels, improving the system's safety in human-machine coexistence environments. In this embodiment, a typical combination of operating parameters can be selected; for example, the operating frequency of the pulse power supply 210 can be set to 18kHz, and the peak voltage can be set to 5kV.

[0028] Please refer to the following: Figure 3 The figure illustrates a typical application scenario of the system of the present invention. The aforementioned core components, such as the dielectric barrier discharge unit, pulse power supply, and current equalization plate, can be integrated and packaged within a housing to form an independent modular purification unit 310. This modular purification unit 310 can be easily installed in various air handling systems, such as the ventilation duct 300 of a central air conditioning system. One or more fans drive the polluted airflow 320 through the modular purification unit 310. After being acted upon by the plasma inside the unit, pathogenic microorganisms in the air are inactivated, pollutants are degraded, and finally, clean purified airflow 330 is output. Accordingly, the complete system composed of this core disinfection system, the housing, and the fans constitutes an air purification device.

[0029] This embodiment also provides a corresponding method for surface-source plasma air disinfection, which includes the following steps: Provide or construct a surface source plasma air disinfection system as described above, which includes a perforated mesh high-voltage electrode 10, a dielectric barrier layer 20, and a fully covered flat grounding electrode 30.

[0030] The air to be processed is passed through the flattened sandwich dielectric barrier discharge unit at an average flow rate of 0.3-1.2 m / s. In this embodiment, the air to be processed can be uniformly blown towards and through the mesh of the high-voltage electrode 10 at an average flow rate of 0.8 m / s by controlling the fan speed. This flow rate range is another key parameter for co-optimization, which ensures that the air has sufficient residence time in the discharge region to react with the active particles, while also ensuring sufficient processing air volume.

[0031] At the same time or after air is introduced, the pulse power supply 210 is activated to supply power to the flat sandwich dielectric barrier discharge unit and its operating frequency is controlled to be 18kHz and the peak voltage is 5kV. Both of these parameters fall within the core range of 15-20kHz and 3-6kV defined by this invention.

[0032] Under the synergistic effect of the aforementioned structural, electrical, and airflow parameters, the high-frequency alternating electric field formed between the high-voltage electrode 10 and the grounding electrode 30 breaks down the flowing air, forming a thin, uniform, and stable surface-source plasma covering the entire electrode area on the surface of the dielectric barrier layer 20. Molecules such as oxygen and water vapor in the air are ionized or excited by high-energy electron collisions, generating a large number of hydroxyl radicals (·OH) and superoxide ions (O2). - Singlet oxygen ( 1 Highly reactive particles such as O2. When a polluted airflow 320 carrying pathogenic microorganisms such as bacteria and viruses passes through this plasma region, these reactive particles will rapidly attack and destroy the cell membranes, proteins, and nucleic acid structures of the pathogens, causing them to become inactive; at the same time, they can also oxidize and decompose chemical pollutants such as formaldehyde and volatile organic compounds.

[0033] Compared to traditional dielectric barrier discharge systems driven by higher voltages or frequencies, the system and method of this embodiment, while ensuring air purification effects, effectively reduce overall energy consumption due to the reduction in operating frequency and peak voltage, and suppress and reduce ozone concentration at the air outlet from the source. This fully demonstrates that the present invention achieves a good balance between energy consumption, efficiency, and safety.

[0034] Example 2 As an optional implementation, this embodiment, based on Embodiment 1, optimizes and refines the materials and specific structural parameters of key components of the flattened sandwich dielectric barrier discharge unit to further improve the system's discharge efficiency, uniformity, reliability, and service life. The overall structure of this embodiment is the same as that of Embodiment 1, and is similarly based on... Figure 1 The main difference lies in the specific implementation of the high-voltage electrode 10 and the dielectric barrier layer 20.

[0035] In a preferred embodiment of the present invention, the high-voltage electrode 10 is a stainless steel wire mesh electrode. Stainless steel has excellent corrosion resistance and electrochemical corrosion resistance, and can work stably in a plasma environment for a long time without being easily oxidized or worn. The wire drawing process makes the electrode surface smoother, reduces burrs, thereby suppressing the generation of tip discharge and helping to form a more uniform glow discharge. More specifically, the aperture ratio of the stainless steel wire mesh electrode is precisely controlled at 70%. The aperture ratio refers to the percentage of the area of ​​the hollow part of the electrode to the total area. A 70% aperture ratio is a balance point achieved between ensuring sufficient airflow permeability (low wind resistance) and maintaining sufficient electrode solidity to form a uniform electric field. If the aperture ratio is too high, the electrode mesh is too sparse, which may lead to uneven electric field and discharge blind zones; if the aperture ratio is too low, it will significantly increase the airflow resistance, increase the fan energy consumption, and reduce the air handling capacity per unit time. In addition, the shape of the mesh can also be further optimized, for example, using waist-shaped holes, which can provide better airflow guidance in a specific direction compared to simple circular or square holes.

[0036] Accordingly, for the dielectric barrier layer 20 in this embodiment, a high-purity alumina ceramic sheet with a thickness of 0.8 mm is selected. High-purity alumina (Al2O3) is a high-performance dielectric material with a high dielectric constant (for example, the dielectric constant of the material selected in this embodiment is approximately 10). This helps to generate a stronger electric field in the air gap under the same electrode spacing and applied voltage, thereby reducing the plasma ignition voltage and sustaining voltage, and indirectly reducing energy consumption. It has extremely high dielectric strength, capable of withstanding electric fields much higher than the operating voltage without breakdown, ensuring the electrical safety of the system. At the same time, it has high mechanical strength, high temperature resistance, and chemical corrosion resistance, and can adapt to long-term harsh working environments. In this embodiment, the thickness of the high-purity alumina ceramic sheet is precisely limited to 0.8 mm. This thickness is achieved by minimizing the dielectric layer thickness while ensuring sufficient mechanical support strength and insulation performance, thereby increasing the equivalent capacitance of the dielectric layer, improving the efficiency of charge transmission and accumulation on the dielectric surface, and facilitating the formation of a stronger and more stable discharge. In addition, to ensure a tight fit with the upper and lower electrodes and eliminate discharge differences caused by uneven local air gaps, the surface flatness of the high-purity alumina ceramic sheet is also required to be high. For example, its unevenness should not exceed 0.02 mm.

[0037] During operation, the optimized system of this embodiment can be used to select another set of parameters within a defined range. For example, the operating frequency of the pulse power supply 210 can be set to 20kHz, the peak voltage to 4kV, and the flow velocity of the air to be processed can be set to 1.0m / s. Due to the use of a higher-performance alumina ceramic dielectric layer and a more rationally structured stainless steel mesh electrode, the system can achieve stable and uniform discharge at a lower sustaining voltage, further improving the uniformity of the electric field distribution and effectively reducing the occurrence of unstable phenomena such as local overheating or filamentary discharge.

[0038] Compared to Example 1, this example further enhances the overall performance of the system by precisely optimizing the materials and dimensions of the high-voltage electrode 10 and the dielectric barrier layer 20. Specifically, not only is energy consumption further reduced, but the uniformity of plasma distribution and the stability of discharge are also improved, resulting in a more stable and reliable disinfection effect. Simultaneously, the use of durable materials such as stainless steel and high-purity alumina ceramic significantly improves the long-term operational reliability and overall service life of the system.

[0039] Example 3 This embodiment provides an improved solution based on the system of Embodiment 1 or Embodiment 2. Specifically, this embodiment further integrates a power closed-loop control system, which aims to enable the system to have adaptive adjustment capabilities, overcome the drift of discharge characteristics caused by factors such as changes in ambient temperature and humidity, air pressure fluctuations, changes in air dust content, or electrode aging, thereby always maintaining the optimal operating point and achieving constant discharge power and stable disinfection effect.

[0040] Please see Figure 2 The figure shows the principle block diagram of the power closed-loop control system in this embodiment. Based on the core flat sandwich dielectric barrier discharge unit and pulse power supply 210, the system adds a voltage / current sensor 230 and a microcontroller 200.

[0041] The voltage / current sensor 230 is electrically connected to the flat sandwich dielectric barrier discharge unit and is used to acquire, in real time and at high frequency, the voltage waveform V(t) applied across the flat sandwich dielectric barrier discharge unit and the current waveform I(t) flowing through the flat sandwich dielectric barrier discharge unit. Since the current waveform of the flat sandwich dielectric barrier discharge unit usually contains a large number of narrow pulse current spikes, the voltage / current sensor 230 needs to have sufficient bandwidth to accurately capture these waveform details.

[0042] The microcontroller 200, as the core of the entire closed-loop control system, can be implemented using devices such as a digital signal processor, a field-programmable gate array (FPGA), or a high-performance microcontroller. This microcontroller 200 executes specific control algorithms and receives detection signals from the voltage / current sensor 230 via its input interface. Figure 5 The signal is represented as feedback signal 240, and an adjustment command is sent to the control terminal of pulse power supply 210 through the output interface. Figure 5 This is represented as control signal 250.

[0043] Combination Figure 5 The signaling interaction timing diagram shown illustrates the working method and process of this power closed-loop control system, as detailed below: System initialization: Preset a target discharge power value P in the microcontroller 200. target .

[0044] Real-time sampling: After the system starts running, the closed-loop control cycle is initiated. The voltage / current sensor 230 continuously samples the voltage and current of the flat sandwich dielectric barrier discharge unit and periodically sends the digitized waveform data as feedback signal 240 to the microcontroller 200.

[0045] Power Calculation: The microcontroller 200 processes the received voltage V(t) and current I(t) data in real time during each calculation cycle. It calculates the average actual discharge power P over one or more discharge cycles T using a numerical integration algorithm, according to the following formula. actual : .

[0046] Deviation Comparison: The microcontroller 200 will calculate the actual power P actual With the preset target power P target By comparison, the power deviation ΔP = P is obtained. target -P actual .

[0047] Instruction generation: Based on the magnitude and sign of the power deviation ΔP, the control logic within the microcontroller 200 (e.g., proportional-integral-derivative control algorithm) generates the corresponding control signal 250. For example, if P actual Less than P target Then control signal 250 will increase the output of command pulse power supply 210; if P actual Greater than P target If so, it instructs the output to be reduced.

[0048] Parameter adjustment: After receiving the control signal 250 from the microcontroller 200, the pulse power supply 210 immediately responds and adjusts its output parameters. The adjustment method can be to fine-tune the peak voltage of the output pulse or to fine-tune its operating frequency, but all adjustments are limited to the core parameter range of 3-6kV and 15-20kHz required by this invention.

[0049] Cyclic feedback: After adjustment by pulse power supply 210, the actual discharge power P of the flat sandwich dielectric barrier discharge unit is... actual The change occurs and is detected again by the voltage / current sensor 230, thus entering the next control cycle. Through the above-described rapid and continuous closed-loop feedback adjustment, the system can automatically compensate for the impact of various internal and external disturbances on the discharge power, ensuring that the actual discharge power is always dynamically stabilized near the preset target value. For example, when the ambient humidity increases, causing the air breakdown voltage to drop, without closed-loop control, the discharge power driven by the fixed voltage will increase unexpectedly; however, the system in this embodiment will detect the power increase and automatically reduce the drive voltage, bringing the power back to the set value.

[0050] In summary, the system provided in this embodiment has strong adaptability and operational stability, ensuring that it can output constant energy for air disinfection under any operating conditions, thereby guaranteeing the consistency and reliability of the disinfection effect and improving the system's energy efficiency and practical value in complex and ever-changing real-world application scenarios.

[0051] Example 4 This embodiment, based on Embodiment 1 or Embodiment 2, further integrates a safety closed-loop control system. It should be noted that this system aims to control harmful byproducts, directly using the ozone concentration at the outlet as a key feedback indicator. By actively adjusting discharge parameters, it ensures that the ozone and other byproducts generated by the system under any operating condition are strictly below preset safety standards. This approach aims to fundamentally solve the potential safety hazards of traditional dielectric barrier discharge technology, and is particularly suitable for densely populated and long-term residence locations such as homes, offices, schools, and hospital wards where air quality requirements are extremely high.

[0052] Please see Figure 4 The figure shows a block diagram of the ozone concentration feedback control system in this embodiment. The system's structure is similar to the power closed-loop system in Embodiment 3, but its feedback source and control objective are completely different. The system also includes a microcontroller 200, a pulse power supply 210, and a core flattened sandwich dielectric barrier discharge unit; the key difference is the addition of an ozone sensor 260.

[0053] Among them, the ozone sensor 260 is a chemical or optical sensor capable of accurately measuring low concentrations of ozone in the air. The ozone sensor 260 is deployed on the outlet side of the flat sandwich dielectric barrier discharge unit, i.e., in the path of the purified airflow 330, so as to monitor the final ozone concentration in the air after plasma treatment in real time and accurately.

[0054] In this embodiment, the microcontroller 200 is configured to execute a control algorithm with safety as the primary objective, and it receives a detection signal from the ozone sensor 260, which is represented in the figure as an ozone concentration feedback signal 270.

[0055] Combination Figure 6 The signaling interaction timing diagram shown illustrates the working method and process of this safety closed-loop control system, as detailed below: Threshold preset: During system initialization, a safe threshold for ozone concentration is preset in the microcontroller 200. For example, based on indoor air quality standards, it can be set to 0.05 ppm. This value is the upper limit that should not be exceeded during system operation.

[0056] Concentration monitoring: After the system starts running, the safety closed-loop control cycle is activated. The ozone sensor 260 continuously monitors the air at the outlet and sends the measured real-time ozone concentration value as an ozone concentration feedback signal 270 to the microcontroller 200.

[0057] Real-time comparison: The microcontroller 200 compares the received real-time concentration value with a preset safety threshold.

[0058] Judgment and Control: Based on the comparison results, the microcontroller 200 performs a judgment and generates control instructions.

[0059] If the detected ozone concentration is higher than or equal to the safety threshold, it indicates that the ozone production has reached the critical level or exceeded the standard. At this time, the microcontroller 200 immediately generates and sends a control signal to the pulse power supply 210 to reduce the output.

[0060] If the detected ozone concentration is below the safety threshold, it indicates that the system is operating within a safe range. In this case, the microcontroller 200 can send a command to maintain the current output. Alternatively, in a more complex control strategy, if the concentration is far below the threshold, a moderate increase in power may be allowed to enhance the disinfection effect, but any attempt to increase power must be made on the premise that the ozone concentration does not exceed the limit.

[0061] Power Supply Response: Upon receiving a control command, the pulse power supply 210 adjusts its output accordingly. For example, upon receiving a command to reduce the output, it will significantly reduce the peak voltage of the output because ozone generation is strongly positively correlated with the energy density of the discharge (especially with the peak voltage). Similarly, all adjustments must still be made within the range of 3-6kV and 15-20kHz.

[0062] Closed-loop formation: Changes in power output directly affect the discharge intensity and ozone generation rate of the flat sandwich dielectric barrier discharge unit. The new ozone concentration is detected by the ozone sensor 260, forming a new round of closed-loop control.

[0063] Therefore, the system in this embodiment implements a proactive, real-time safety management mechanism. It no longer relies solely on pre-design to passively limit ozone production, but instead constructs an effective safety guarantee through online monitoring and dynamic feedback. Even under certain extreme conditions (such as extremely low temperatures and humidity, which easily lead to higher ozone concentrations), the system can automatically intervene, reducing power to ensure that the air quality at the outlet always meets the safety standards for human-machine coexistence.

[0064] Example 5 This embodiment provides a dual-closed-loop collaborative control scheme that integrates the power closed-loop control system of Embodiment 3 with the safety closed-loop control system of Embodiment 4. This scheme aims to achieve an intelligent operation mode that prioritizes safety while also considering efficiency; that is, while ensuring absolute safety of ozone concentration, it strives to stabilize the discharge power at the target value required for efficient disinfection.

[0065] The system in this embodiment integrates all the key components of embodiments 3 and 4 in hardware, namely, a voltage / current sensor 230 electrically connected to the flattened sandwich dielectric barrier discharge unit, and an ozone sensor 260 deployed on the system's outlet side. Both sensors send their respective detection signals (feedback signal 240 and ozone concentration feedback signal 270) to the same more powerful microcontroller 200.

[0066] Accordingly, the microcontroller 200 internally runs a composite control algorithm with priority judgment logic, the core idea of ​​which is that safety control has higher priority than power control. The specific workflow is as follows: During system initialization, the microcontroller 200 presets two key parameters: a target discharge power P. target And an ozone concentration safety threshold.

[0067] During system operation, the microcontroller 200 simultaneously receives and processes real-time data from the voltage / current sensor 230 and the ozone sensor 260.

[0068] In each control cycle, the microcontroller 200 first checks the ozone concentration feedback signal 270 from the ozone sensor 260.

[0069] Safety Priority Decision: If the measured ozone concentration approaches or exceeds a preset safety threshold, the safety control logic is triggered and gains supreme control. At this time, the microcontroller 200 immediately ignores the current power control target and forcibly sends a command to the pulse power supply 210 to reduce its output until the ozone concentration falls back within the safe range. During this period, the power control cycle is suspended or its output is overridden by the safety command.

[0070] Efficiency Stability Control: The power closed-loop control logic is activated or allowed to execute only when the ozone concentration is confirmed to be within the allowable range below the safety threshold. At this time, the microcontroller 200 calculates the actual power P based on the feedback signal 240 from the voltage / current sensor 230. actual and with the target power P target The system compares the outputs and generates corresponding control signals 250 to fine-tune the output of the pulse power supply 210, achieving constant power operation. This dual-closed-loop collaborative control strategy effectively resolves the potential conflict between disinfection efficiency and safety. It ensures a safety baseline for system operation while seeking optimal disinfection performance and stability. For example, in an initially clean environment with suitable temperature and humidity, the system can operate efficiently at the target power because ozone production is very low. If the environment suddenly becomes dry, making ozone easier to generate, the safety loop will immediately intervene, appropriately reducing the power to suppress ozone. Although the power may be slightly lower than the target value at this time, safety is ensured. When the environment returns to normal, the system will automatically increase the power back to the target value.

[0071] The technical solution provided in this embodiment achieves a good balance in terms of efficiency, energy consumption, and safety through intelligent collaborative control, thus possessing high practical value.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A surface area plasma air disinfecting system characterized by, include: A flat sandwich dielectric barrier discharge unit includes a high-voltage electrode, a dielectric barrier layer, and a ground electrode that are stacked and tightly bonded together in sequence; wherein, the high-voltage electrode has a hollow mesh flat structure, the ground electrode has a fully covered flat plate structure, and the high-voltage electrode and the ground electrode form an asymmetric electrode configuration to generate a fully covered surface source plasma on the surface of the dielectric barrier layer. A pulse power supply, electrically connected to the high-voltage electrode and the ground electrode, is configured to output a pulse voltage with an operating frequency of 15-20kHz and a peak voltage of 3-6kV.

2. The area source plasma air disinfection system of claim 1, wherein, The high-voltage electrode is a stainless steel wire mesh electrode with an opening rate of 70%.

3. The area source plasma air disinfection system of claim 1, wherein, The dielectric barrier layer is a high-purity alumina ceramic sheet with a thickness of 0.8 mm.

4. The area source plasma air disinfection system of claim 1, wherein, It also includes a power closed-loop control system, which includes: A voltage / current sensor electrically connected to the flat sandwich dielectric barrier discharge unit; The microcontroller is configured to receive the detection signal from the voltage / current sensor and adjust the output of the pulse power supply according to a preset target power.

5. The area source plasma air disinfection system of claim 1, wherein, It also includes a safety closed-loop control system, which includes: An ozone sensor is disposed on the gas outlet side of the flat sandwich dielectric barrier discharge unit. The microcontroller is configured to receive the detection signal from the ozone sensor and adjust the output of the pulse power supply according to a preset safety threshold.

6. The area source plasma air disinfection system of claim 4, wherein, It also includes an ozone sensor disposed on the gas outlet side of the flat sandwich dielectric barrier discharge unit; Furthermore, the microcontroller is configured to receive the detection signal from the ozone sensor, and, prioritizing the detection signal from the ozone sensor, adjust the output of the pulse power supply according to the preset target power when the ozone concentration is below a preset safety threshold.

7. A method for disinfecting air using surface-source plasma, characterized in that, This method is performed using the area source plasma air sterilization system of claim 1, and includes the following steps: A pulse power supply is used to power the flat sandwich dielectric barrier discharge unit, and the operating frequency of the pulse power supply is controlled to be 15-20kHz, and the peak voltage is 3-6kV. The air to be processed is passed through the flattened sandwich dielectric barrier discharge unit at an average flow rate of 0.3-1.2 m / s.

8. The method for surface-source plasma air disinfection according to claim 7, characterized in that, Also includes: The discharge power of the flattened sandwich dielectric barrier discharge unit is monitored in real time, and the output of the pulse power supply is adjusted based on the deviation between the discharge power and the preset target power.

9. The method for surface-source plasma air disinfection according to claim 7, characterized in that, Also includes: The ozone concentration on the outlet side of the flat sandwich dielectric barrier discharge unit is monitored in real time, and when the ozone concentration exceeds a preset safety threshold, the output of the pulse power supply is preferentially reduced.

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