Multi-waveform synergistic excitation nanosecond pulse dielectric barrier discharge ozone generation system

Abstract

The present application relates to the technical field of ozone generation, and discloses a multi-waveform synergistic excitation nanosecond pulse dielectric barrier discharge ozone generation system, which comprises a programmable high-voltage alternating current power supply, a nanosecond pulse power supply, a waveform switching or superimposition module, a dielectric barrier discharge reactor, a gas flow control module, an ozone detection module, a NOx detection module, a voltage and current acquisition module, a temperature detection module and an adaptive control module, the waveform switching or superimposition module is used for switching or superimposition output between excitation modes, and the adaptive control module is used for automatically adjusting pulse width, repetition frequency, rising edge, falling edge, duty ratio, peak voltage, gas flow and excitation mode according to real-time acquisition of ozone concentration, unit energy consumption, NOx byproduct concentration, reactor temperature rise and discharge stability indexes; the present application effectively controls nitrogen oxide generation and improves ozone gas purity.

Description

Technical Field

[0001] This invention relates to the field of ozone generation technology, specifically to a nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation. Background Technology

[0002] Ozone (O3) is widely used in water treatment, air purification, food disinfection, flue gas treatment, medical sterilization and other fields due to its strong oxidizing properties and environmental protection characteristics. However, because ozone is chemically unstable and easily decomposes at room temperature, in-situ generation is usually adopted in industrial applications. Dielectric barrier discharge (DBD) has become the most mainstream ozone generation method because it can generate large-area, high-energy low-temperature plasma under normal pressure and has the ability to generate ozone with high flux, high concentration and relatively high efficiency. Since the first use of gas discharge to generate ozone, researchers have carried out a lot of work on the electrical parameters, reactor structure, dielectric materials and gas conditions of DBD in order to improve ozone generation efficiency and reduce energy consumption.

[0003] However, traditional DBD ozone generators typically use metal electrodes (such as stainless steel, copper, and aluminum) and sinusoidal AC power, resulting in significant bottlenecks in ozone generation efficiency. The main reasons include: a considerable portion of the discharge energy is converted into Joule heat, heating the electrodes and plasma gas, leading to accelerated ozone decomposition at high temperatures; the cooling effect of metal electrodes is limited, making it difficult to effectively suppress temperature rise within the discharge gap; furthermore, the relatively concentrated electron energy distribution under traditional sinusoidal AC excitation makes it difficult to balance the dissociation of oxygen molecules by high-energy electrons with the suppression of ozone decomposition by low-energy electrons; and, more critically, traditional DBD systems lack effective control over the byproduct NOx during operation. When using air or nitrogen-containing gas sources, high-energy electrons dissociate nitrogen molecules, generating nitrogen oxides (NOx), which not only reduces ozone purity but may also cause secondary pollution. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems by designing a nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation.

[0005] This invention provides a nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation, comprising a programmable high-voltage AC power supply, a nanosecond pulse power supply, a waveform switching or superposition module, a dielectric barrier discharge reactor, a gas flow control module, an ozone detection module, a NOx detection module, a voltage and current acquisition module, a temperature detection module, and an adaptive control module, wherein...

[0006] The waveform switching or superposition module is electrically connected to the programmable high-voltage AC power supply, the nanosecond pulse power supply and the dielectric barrier discharge reactor, respectively, and is used to switch or superimpose outputs between excitation modes.

[0007] The adaptive control module is connected to the ozone detection module, NOx detection module, voltage and current acquisition module, temperature detection module, gas flow control module, and waveform switching or overlay module, respectively. It is used to automatically adjust the pulse width, repetition frequency, rising edge, falling edge, duty cycle, peak voltage, gas flow rate, and excitation mode based on the real-time collected ozone concentration, unit energy consumption, NOx by-product concentration, reactor temperature rise, and discharge stability indicators.

[0008] Optionally, in a first implementation of the present invention, the excitation mode includes an AC excitation mode, a unipolar nanosecond pulse excitation mode, a bipolar nanosecond pulse excitation mode, and an AC superimposed nanosecond pulse excitation mode.

[0009] Optionally, in the second implementation of the present invention, the waveform switching or superposition module adopts a bipolar nanosecond pulse excitation mode during the first 30 seconds of the discharge start-up phase, with a pulse repetition frequency of 8kHz-10kHz and a pulse width of 100ns-200ns. When the ozone concentration is detected to be greater than 3000ppm and the rate of change is less than ±5%, it automatically switches to an AC superposition nanosecond pulse excitation mode, with an AC fundamental frequency of 6kHz-8kHz and a nanosecond pulse superposition amplitude of 20%-50% of the AC peak voltage.

[0010] Optionally, in a third implementation of the present invention, the dielectric barrier discharge reactor uses circulating pure water as the grounding water electrode, a grooved stainless steel tube as the inner high-voltage electrode, and a quartz glass tube as the dielectric layer. The discharge gap of the dielectric barrier discharge reactor is 2 mm, the effective discharge length is 45 mm, the inner diameter of the quartz glass tube is 20 mm, the outer diameter is 25 mm, the outer diameter of the inner high-voltage electrode is 16 mm, and the discharge area of ​​the reactor is composed of a quartz glass tube with a cross-sectional length of 240 mm. The grounding water electrode is pure water with a conductivity of 2 μS / m.

[0011] Optionally, in the fourth implementation of the present invention, the voltage and current acquisition module acquires the discharge voltage and current waveforms through a high-voltage probe and a current coil, and calculates the discharge power P using the voltage-charge Lissajous figure method. The calculation formula is as follows:

[0012] ;

[0013] Where T represents the sampling window duration, t represents the instantaneous time variable, U(t) represents the instantaneous discharge voltage at time t, and I(t) represents the instantaneous discharge current at time t.

[0014] Optionally, in the fifth implementation of the present invention, the gas flow control module adopts a mass flow controller, the gas source is high-purity oxygen with a purity of 99.999%, the gas flow rate is continuously adjustable from 0 to 5 SLPM, and the optimal working flow rate is 2 SLPM.

[0015] Optionally, in the sixth implementation of the present invention, the ozone detection module adopts a non-dispersive ultraviolet absorption technology ozone analyzer, and the temperature detection module includes a fiber optic thermometer and a circulating water temperature sensor for monitoring the gas outlet temperature and the water electrode outlet temperature.

[0016] Optionally, in the seventh implementation of the present invention, the NOx detection module adopts chemiluminescence or ultraviolet absorption. When the detected NOx concentration exceeds 50 ppm, the adaptive control module automatically switches the excitation mode to the bipolar nanosecond pulse excitation mode.

[0017] Optionally, in the eighth implementation of the present invention, in the adaptive control module, when a transient filamentary discharge pulse train appears in the voltage-current waveform and each filamentary discharge corresponds to a micro-discharge channel, it is determined to be a stable filamentary discharge mode; if the filamentary pulse disappears or uneven discharge occurs, the duty cycle is automatically adjusted or switched to a bipolar nanosecond pulse excitation mode.

[0018] Optionally, in the ninth implementation of the present invention, the optimization target of the adaptive control module is: ozone generation efficiency at 6kHz frequency is greater than or equal to 391.66g / kWh, ozone concentration at 7kHz frequency is greater than or equal to 12293.59ppm, ozone generation efficiency at full frequency band operation is greater than or equal to 160g / kWh, and ozone concentration fluctuation at 400 minutes of continuous operation is less than or equal to ±3%.

[0019] The technical solution provided by this invention, a nanosecond pulse dielectric barrier discharge ozone adaptive analysis system with multi-waveform coordinated excitation, includes a programmable high-voltage AC power supply, a nanosecond pulse power supply, a waveform switching or superposition module, a dielectric barrier discharge reactor, a gas flow control module, an ozone detection module, a NOx detection module, a voltage and current acquisition module, a temperature detection module, and an adaptive control module. This invention employs a multi-waveform coordinated excitation mode, including AC superposition of nanosecond pulses, combined with a water electrode structure, resulting in ozone generation efficiency far exceeding that of traditional methods, achieving a synergistic improvement in both high concentration and high efficiency. Through the adaptive control module's dynamic optimization of parameters such as frequency, pulse width, and peak voltage, it overcomes the limitations of traditional DBD ozone generators where ozone generation efficiency increases with energy density. The system overcomes the drawback of a sharp drop in efficiency by using circulating pure water as the grounding electrode. Utilizing the transparency and direct cooling effect of the water electrode, it achieves efficient heat dissipation from the discharge gap, effectively suppressing the thermal decomposition of ozone. The built-in NOx detection module promotes efficient oxygen molecule dissociation while inhibiting nitrogen oxide generation channels, significantly reducing the emission of harmful byproducts during ozone synthesis. Multi-mode adaptive switching ensures discharge stability. The use of a water electrode instead of a traditional metal grounding electrode eliminates the need for complex metal electrode processing and cooling water jacket structures. Furthermore, the use of pure water as the electrode medium and coolant reduces reactor manufacturing costs. The transparency of the water electrode also facilitates direct observation of the discharge morphology, providing a direct basis for discharge diagnosis and adaptive control. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention.

[0021] Figure 1 This is a schematic diagram of the structure of a nanosecond pulse dielectric barrier discharge ozone adaptive analysis system with multi-waveform coordinated excitation provided in an embodiment of the present invention. Detailed Implementation

[0022] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” or “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0023] For ease of understanding, the specific process of the embodiments of the present invention is described below. Please refer to [link / reference]. Figure 1 A schematic diagram of the structure of the nanosecond pulse dielectric barrier discharge ozone adaptive analysis system with multi-waveform coordinated excitation provided in this embodiment of the invention. The system specifically includes:

[0024] The system includes a programmable high-voltage AC power supply, a nanosecond pulse power supply, a waveform switching or overlay module, a dielectric barrier discharge reactor, a gas flow control module, an ozone detection module, a NOx detection module, a voltage and current acquisition module, a temperature detection module, and an adaptive control module.

[0025] The waveform switching or superposition module is electrically connected to the programmable high-voltage AC power supply, the nanosecond pulse power supply and the dielectric barrier discharge reactor, respectively, and is used to switch or superimpose the output between the excitation modes including AC excitation mode, unipolar nanosecond pulse excitation mode, bipolar nanosecond pulse excitation mode and AC superimposed nanosecond pulse excitation mode.

[0026] The adaptive control module is connected to the ozone detection module, NOx detection module, voltage and current acquisition module, temperature detection module, gas flow control module, and waveform switching or overlay module, respectively. It is used to automatically adjust the pulse width, repetition frequency, rise time, fall time, duty cycle, peak voltage, gas flow rate, and excitation mode based on the real-time collected ozone concentration, unit energy consumption, NOx by-product concentration, reactor temperature rise, and discharge stability indicators.

[0027] In this embodiment, the waveform switching or superposition module adopts a bipolar nanosecond pulse excitation mode during the first 30 seconds of the discharge start-up phase, with a pulse repetition frequency of 8kHz-10kHz and a pulse width of 100ns-200ns. When the ozone concentration is detected to be greater than 3000ppm and the rate of change is less than ±5%, it automatically switches to the AC superposition nanosecond pulse excitation mode, with an AC fundamental frequency of 6kHz-8kHz and a nanosecond pulse superposition amplitude of 20%-50% of the AC peak voltage.

[0028] In this embodiment, the dielectric barrier discharge reactor uses circulating pure water as the grounding water electrode, a grooved stainless steel tube as the inner high-voltage electrode, and a quartz glass tube as the dielectric layer. The discharge gap of the dielectric barrier discharge reactor is 2 mm, the effective discharge length is 45 mm, the inner diameter of the quartz glass tube is 20 mm, the outer diameter is 25 mm, the outer diameter of the inner high-voltage electrode is 16 mm, and the discharge area of ​​the reactor is composed of a quartz glass tube with a cross-sectional length of 240 mm. The grounding water electrode is pure water with a conductivity of 2 μS / m.

[0029] In this embodiment, the voltage and current acquisition module acquires the discharge voltage and current waveforms through a high-voltage probe and a current coil, and calculates the discharge power P using the voltage-charge Lissajous figure method. The calculation formula is as follows:

[0030] ;

[0031] Where T represents the sampling window duration, t represents the instantaneous time variable, U(t) represents the instantaneous discharge voltage at time t, and I(t) represents the instantaneous discharge current at time t.

[0032] In this embodiment, the gas flow control module adopts a mass flow controller, the gas source is high-purity oxygen with a purity of 99.999%, the gas flow rate is continuously adjustable from 0 to 5 SLPM, and the optimal working flow rate is 2 SLPM.

[0033] In this embodiment, the ozone detection module employs a non-dispersive ultraviolet absorption technology ozone analyzer, and the temperature detection module includes a fiber optic thermometer and a circulating water temperature sensor for monitoring the gas outlet temperature and the water electrode outlet temperature. The ozone analyzer based on non-dispersive ultraviolet absorption technology utilizes the characteristic absorption properties of ozone molecules in the ultraviolet band. By measuring the attenuation of ultraviolet light intensity before and after the gas sample passes through, it outputs the ozone concentration at the gas outlet in real time and accurately. Its measurement accuracy can meet the detection requirements of a wide range from low to high concentrations, and it has a fast response speed and is not affected by oxygen or other associated gases. The fiber optic thermometer in the temperature detection module is used to monitor the reactor. The gas temperature at the gas outlet is measured using fiber optic sensing technology, which avoids electromagnetic interference under high-voltage discharge conditions, enabling accurate non-contact or contact temperature measurement. The circulating water temperature sensor is embedded in the water electrode circulation loop, monitoring the water temperature at the inlet and outlet of the water electrode. The adaptive control module reads the ozone concentration, gas outlet temperature, and water electrode inlet / outlet temperatures in real time. Combined with the built-in temperature rise-efficiency model, when the gas outlet temperature rises above a threshold, the ozone decomposition rate increases significantly. The module dynamically adjusts the discharge power, duty cycle, or excitation mode to suppress the thermal decomposition of ozone and maintain an efficient ozone generation process.

[0034] In this embodiment, the NOx detection module uses chemiluminescence or ultraviolet absorption. When the detected NOx concentration exceeds 50 ppm, the adaptive control module automatically switches the excitation mode to the bipolar nanosecond pulse excitation mode. Due to its alternating positive and negative electric field characteristics, the bipolar nanosecond pulse excitation mode can make the electron energy distribution in the discharge space more uniform, avoid the concentration of electrons with excessively high energy in some areas, and thus significantly reduce the dissociation probability of nitrogen molecules while maintaining a high ozone generation efficiency, thereby suppressing the generation of NOx. Furthermore, in the bipolar nanosecond pulse mode, the distribution of micro-discharge channels is more diffuse and uniform, which helps to reduce local high-temperature hotspots caused by the merging of discharge filament channels. High temperature is one of the important factors promoting NOx generation. Therefore, the adaptive control module automatically switches the excitation mode to the bipolar nanosecond pulse mode and can simultaneously adjust the repetition frequency to above 3kHz to further optimize the electron energy distribution. Under the same discharge power conditions, the bipolar nanosecond pulse mode can reduce the NOx concentration by about 60% compared to the AC mode, while controlling the ozone generation efficiency reduction to within 10%, thereby ensuring gas purity while meeting the high concentration ozone requirements.

[0035] In this embodiment, in the adaptive control module, when a transient filamentary discharge pulse train appears in the voltage-current waveform, and each filamentary discharge corresponds to a micro-discharge channel, it is determined to be a stable filamentary discharge mode. If the filamentary pulses disappear or uneven discharge occurs, the duty cycle is automatically adjusted or switched to a bipolar nanosecond pulse excitation mode. During the dielectric barrier discharge process, due to the insulating characteristics of the dielectric layer, several transient discharge filamentary structures will be formed in the discharge space. These filamentary structures can be further developed into cylindrical micro-discharge channels. The generation and extinction of each micro-discharge channel represents an independent discharge breakdown process. All ozone synthesis reactions occur inside and around these micro-discharge channels. Based on this discharge mechanism, a discharge stability discrimination rule is built into the adaptive control module: when the voltage-current waveform captured in real time by the voltage and current acquisition module presents a continuous, uniform, high-repetition-frequency transient filamentary discharge pulse train, and each filamentary pulse corresponds to a clear and uniform micro-discharge channel, the stability is determined to be stable. During the establishment and extinction of the micro-discharge channel, the adaptive control module determines that the current discharge is in a stable filamentary discharge mode. At this time, since the water electrode can act as a distributed resistor to ensure that the microwave current is evenly distributed on the electrode surface, the system maintains the current excitation parameters. Conversely, when the filamentary pulses in the voltage-current waveform are significantly reduced or disappear, or when large-scale non-uniform discharge occurs, it indicates that the discharge uniformity has deteriorated, which may lead to a decrease in ozone production and local overheating of the electrode. In response to this situation, the adaptive control module first attempts to gradually adjust the duty cycle without changing the excitation mode to restore the uniformity of the filamentary discharge. If the duty cycle adjustment is ineffective, it automatically switches to the bipolar nanosecond pulse excitation mode. Due to its steep rising edge and alternating positive and negative electric field distribution, the bipolar nanosecond pulse can induce more dispersed and uniform micro-discharge channels in the discharge gap, thereby suppressing the merging and disappearance of filamentary pulses, restoring a stable micro-discharge channel distribution, and ensuring that the ozone generation process continues to be efficient.

[0036] In this embodiment, the optimization objectives of the adaptive control module are: ozone generation efficiency greater than or equal to 391.66 g / kWh at 6 kHz frequency, ozone concentration greater than or equal to 12293.59 ppm at 7 kHz frequency, ozone generation efficiency greater than or equal to 160 g / kWh across the entire frequency band, and ozone concentration fluctuation less than or equal to ±3% during 400 minutes of continuous operation.

[0037] Example 1:

[0038] This embodiment provides a nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation, which is particularly suitable for high-efficiency ozone generation scenarios under high-purity oxygen sources. It includes a programmable high-voltage AC power supply, a nanosecond pulse power supply, a waveform switching or superposition module, a dielectric barrier discharge reactor, a mass flow controller (AlcatKM 7100), an ozone analyzer (OSTI 964BT, non-dispersive ultraviolet absorption technology), a NOx detection module, a high-voltage probe (Tektronix P6015A), a current coil (Pearson 2878), an oscilloscope (Tektronix MDO3054C, 500MHz, 5Gs / s), a fiber optic thermometer (AnritsuFL-2000), and a circulating water device (LX-150). The dielectric barrier discharge reactor structure uses circulating pure water (conductivity 2μS / m) as the ground electrode, a grooved stainless steel tube as the inner high-voltage electrode, and a quartz glass tube as the dielectric layer. The discharge gap is 2mm, the effective discharge length is 45mm, the inner diameter of the quartz glass tube is 20mm and the outer diameter is 25mm, the outer diameter of the inner high voltage electrode is 16mm, and the discharge area is composed of a quartz glass tube with a cross-sectional length of 240mm.

[0039] When the system starts up, the adaptive control module's command waveform switching or superposition module adopts a bipolar nanosecond pulse excitation mode, with a pulse repetition frequency of 9kHz and a pulse width of 150ns. The gas flow control module sets the flow rate of high-purity oxygen (99.999%) to 2SLPM, and the initial temperature of the circulating water to 20℃. The voltage and current acquisition module acquires voltage and current waveforms in real time. This experiment uses the QU Lissajous figure method to determine the electrical power of the DBD by calculating the area of ​​the figure. The area of ​​the voltage-charge Lissajous figure increases with the increase of the peak discharge voltage, indicating that there is a linear relationship between the peak voltage and the discharge power. This shows that the water electrode reactor can control the discharge power by adjusting the peak voltage, thereby improving energy utilization efficiency and producing more ozone. To better understand the effect of voltage modulation on ozone generation, the electron energy distribution in the discharge region was calculated. Using BOLSIG+ software, the relationship between the average electron energy (eV) and the reduction field strength (E / N) of the most common electron collision reaction in O2 plasma was calculated.

[0040] When the ozone detection module measures an ozone concentration of 3000 ppm or higher with a change rate of less than ±5%, the adaptive control module automatically switches to the AC superimposed nanosecond pulse excitation mode: the AC fundamental frequency is set to 7 kHz, the peak voltage is 7.5 kV, and the nanosecond pulse superposition amplitude is 35% of the AC peak voltage (i.e., 2.6 kV). At this time, the voltage-charge Lissajous figure area increases significantly, the discharge power increases to 23.12 W, and the specific input energy reaches 693.7 J / L. The ozone detection module displays an outlet ozone concentration of 12293.59 ± 3.30 ppm, and the ozone generation efficiency is 231 g / kWh. At a discharge frequency of 6 kHz, when the specific input energy is 23.5 J / L, the system achieves a maximum ozone generation efficiency of 391.66 g / kWh, corresponding to an ozone concentration of 1193.04 ppm. The main reason for this phenomenon is that as the energy density gradually increases, the excitation and collision of electron vibrations also intensify, leading to the violent decomposition of oxygen molecules and further exacerbating the collisions between the decomposed oxygen atoms and third molecules. However, as the SIE gradually increases, the ozone generation efficiency at each discharge frequency decreases, which is due to the enhanced ozone decomposition reaction caused by the increase in temperature.

[0041] The temperature detection module monitors the gas outlet and water electrode outlet temperatures in real time. The water electrode outlet temperature remains constant at the initial settings of 10℃, 15℃, 20℃, and 25℃, indicating excellent heat transfer performance. At an initial water temperature of 20℃, the initial gas inlet temperatures at different discharge frequencies (5-10kHz) are 32.8℃, 33.3℃, ​​33.8℃, 33.9℃, 33℃, and 32.5℃, respectively. As discharge progresses, due to the cooling effect of the circulating water, the gas outlet temperature is slightly lower than the inlet temperature, with the largest decreases at 6kHz and 9kHz, dropping from 33.3℃ to 32.9℃ and from 33℃ to 32.6℃, respectively. This cooling effect effectively inhibits the high-temperature decomposition of ozone.

[0042] Example 2:

[0043] This embodiment, based on Embodiment 1, further enhances the adaptive control module's real-time monitoring and response capabilities for electron energy distribution, NOx byproducts, and discharge frequency characteristics. It is particularly suitable for scenarios with fluctuating gas source purity or requiring wide frequency adjustment. During system initialization, the adaptive control module executes a frequency scanning program, recording the specific input energy corresponding to different discharge voltages within the range of 5kHz to 10kHz. The results show that at 8kHz, when the discharge voltage increases from 5.73kV to 8.80kV, the SiE increases from 4.9J / L to 693.7J / L, and the corresponding discharge power increases from 0.16W to 23.12W. This frequency is close to the power supply center frequency, which helps improve energy utilization efficiency. The adaptive control module selects the optimal operating frequency based on the current target.

[0044] To effectively suppress NOx byproducts, the system monitors NOx concentration in real time. When the NOx concentration exceeds 50 ppm, the adaptive control module automatically switches the excitation mode to a bipolar nanosecond pulse excitation mode. The switching is also based on electron energy calculations: using BOLSIG+ software, the relationship between the average electron energy (eV) and the reduction field strength (E / N) in oxygen plasma was calculated. As the reduction field strength increases, low-energy electrons decrease, while the distribution of high-energy electrons expands, resulting in an average electron energy exceeding 1.4 eV. In the bipolar nanosecond pulse mode, the peak voltage increases, the reduction field strength is enhanced, and the average electron energy can be increased to over 1.6 eV, which is beneficial for the efficient dissociation of oxygen molecules to generate ozone, while simultaneously suppressing the formation channels of nitrogen oxides.

[0045] Specifically, when the NOx detection module detects a concentration increase to 55 ppm, the adaptive control module commands the waveform switching or superposition module to switch to a bipolar nanosecond pulse mode. The pulse repetition frequency is set to 10 kHz, the pulse width is compressed to 100 ns, and both the rise and fall edges are controlled within 30 ns. At this time, the voltage and current acquisition module detects a denser transient filamentary discharge pulse train, and the generation and extinction of each micro-discharge channel are clearly distinguishable, consistent with the characteristics of filamentary discharge. The system calculates the discharge power using the area of ​​a Lissajous figure and adjusts the peak voltage in real time to maintain the average electron energy in the range of 1.5-1.8 eV. After the switch, the NOx concentration rapidly decreases to below 12 ppm, while the ozone concentration gradually increases to above 11500 ppm, with the ozone generation efficiency remaining at around 210 g / kWh.

[0046] Furthermore, the adaptive control module dynamically adjusts the specific input energy based on ozone concentration and efficiency characteristic curves. In the low SIE region (e.g., 20-50 J / L), the ozone generation efficiency is high (up to 391.66 g / kWh), suitable for energy-saving priority scenarios. In the high SIE region, such as 400-700 J / L, the ozone concentration can exceed 12000 ppm, suitable for high-concentration demand scenarios. When the system detects a temperature change trend of more than 2°C in the gas outlet temperature, it will automatically reduce the SIE or switch to bipolar pulse mode to reduce the thermal effect and ensure that the ozone decomposition rate is below 5%. This embodiment realizes intelligent adaptive control based on electronic energy and NOx emissions.

[0047] Example 3:

[0048] This embodiment describes in detail the adaptive optimization process of the system under all operating conditions under multi-waveform collaborative excitation, and verifies the superiority of the system using comparative data from the paper.

[0049] The system supports four excitation modes: AC excitation mode, unipolar nanosecond pulse excitation mode, bipolar nanosecond pulse excitation mode, and AC superimposed nanosecond pulse excitation mode. The adaptive control module automatically adjusts the pulse width (50ns-500ns), repetition frequency (5kHz-10kHz), rise / fall time (≤50ns), duty cycle (20%-80%), peak voltage (5kV-9kV), gas flow rate (0-5SLPM), and excitation mode based on real-time collected ozone concentration, unit energy consumption, NOx concentration, reactor temperature rise, and discharge stability indicators. During the first 30 seconds of the discharge initiation phase, the system defaults to the bipolar nanosecond pulse excitation mode, with a pulse repetition frequency of 8kHz-10kHz and a pulse width of 100ns-200ns. In this mode, the voltage and current waveforms exhibit typical transient filamentary discharge pulse trains, with each filamentary discharge corresponding to a micro-discharge channel. The adaptive control module calculates the discharge power in real time using the voltage-charge Lissajous figure method. When the ozone concentration is detected to be greater than 3000ppm and the rate of change is less than ±5%, it automatically switches to the AC superimposed nanosecond pulse excitation mode. The AC fundamental frequency is 6kHz-8kHz, and the nanosecond pulse superposition amplitude is 20%-50% of the AC peak voltage.

[0050] The system underwent a 400-minute continuous operation stability test at a frequency of 7kHz: the ozone concentration remained stable at around 13,000ppm, the efficiency remained stable at approximately 200g / kWh, and the fluctuation was less than ±3%. The temperature detection module showed that during long-term operation, the gas outlet temperature was consistently lower than the initial inlet temperature, confirming the continuous cooling effect of the water electrode.

[0051] When the adaptive control module detects uneven discharge in the voltage-current waveform, it automatically adjusts the duty cycle or switches to a bipolar nanosecond pulse excitation mode until the typical filamentary discharge pattern is restored. Simultaneously, the system optimizes the reduction field strength E / N based on the electron energy distribution curve, ensuring the average electron energy remains within the optimal range of 1.4-2.0 eV, which is conducive to ozone generation and inhibits decomposition. This embodiment fully demonstrates the high efficiency, stability, and superiority of this multi-waveform collaborative adaptive system over a wide operating range, providing a reliable intelligent solution for industrial ozone generation.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended technical solutions and their equivalents.

Claims

1. A nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation, characterized in that, It includes a programmable high-voltage AC power supply, a nanosecond pulse power supply, a waveform switching or overlay module, a dielectric barrier discharge reactor, a gas flow control module, an ozone detection module, a NOx detection module, a voltage and current acquisition module, a temperature detection module, and an adaptive control module. The waveform switching or superposition module is electrically connected to the programmable high-voltage AC power supply, the nanosecond pulse power supply and the dielectric barrier discharge reactor, respectively, and is used to switch or superimpose outputs between excitation modes. The adaptive control module is connected to the ozone detection module, NOx detection module, voltage and current acquisition module, temperature detection module, gas flow control module, and waveform switching or overlay module, respectively. It is used to automatically adjust the pulse width, repetition frequency, rising edge, falling edge, duty cycle, peak voltage, gas flow rate, and excitation mode based on the real-time collected ozone concentration, unit energy consumption, NOx by-product concentration, reactor temperature rise, and discharge stability indicators.

2. The nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation as described in claim 1, characterized in that, The excitation modes include AC excitation mode, unipolar nanosecond pulse excitation mode, bipolar nanosecond pulse excitation mode, and AC superimposed nanosecond pulse excitation mode.

3. The nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation as described in claim 2, characterized in that, The waveform switching or superposition module adopts a bipolar nanosecond pulse excitation mode for the first 30 seconds of the discharge start-up phase, with a pulse repetition frequency of 8kHz-10kHz and a pulse width of 100ns-200ns. When the ozone concentration is detected to be greater than 3000ppm and the rate of change is less than ±5%, it automatically switches to an AC superposition nanosecond pulse excitation mode, with an AC fundamental frequency of 6kHz-8kHz and a nanosecond pulse superposition amplitude of 20%-50% of the AC peak voltage.

4. The nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation as described in claim 1, characterized in that, The dielectric barrier discharge reactor uses circulating pure water as the grounding water electrode, a grooved stainless steel tube as the inner high-voltage electrode, and a quartz glass tube as the dielectric layer. The discharge gap of the dielectric barrier discharge reactor is 2 mm, the effective discharge length is 45 mm, the inner diameter of the quartz glass tube is 20 mm, the outer diameter is 25 mm, the outer diameter of the inner high-voltage electrode is 16 mm, and the discharge area of ​​the reactor is composed of a quartz glass tube with a cross-sectional length of 240 mm. The grounding water electrode is pure water with a conductivity of 2 μS / m.

5. The nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation as described in claim 1, characterized in that, The voltage and current acquisition module acquires the discharge voltage and current waveforms through a high-voltage probe and a current coil, and calculates the discharge power P using the voltage-charge Lissajous figure method. The calculation formula is as follows: ； Where T represents the sampling window duration, t represents the instantaneous time variable, U(t) represents the instantaneous discharge voltage at time t, and I(t) represents the instantaneous discharge current at time t.

6. The nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation as described in claim 1, characterized in that, The gas flow control module uses a mass flow controller, with the gas source being high-purity oxygen with a purity of 99.999%. The gas flow rate is continuously adjustable from 0 to 5 SLPM, and the optimal working flow rate is 2 SLPM.

7. The nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation as described in claim 1, characterized in that, The ozone detection module uses a non-dispersive ultraviolet absorption technology ozone analyzer, and the temperature detection module includes a fiber optic thermometer and a circulating water temperature sensor to monitor the gas outlet temperature and the water electrode outlet temperature.

8. The nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation as described in claim 1, characterized in that, The NOx detection module uses chemiluminescence or ultraviolet absorption. When the detected NOx concentration exceeds 50 ppm, the adaptive control module automatically switches the excitation mode to bipolar nanosecond pulse excitation mode.

9. The nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation as described in claim 1, characterized in that, In the adaptive control module, when a transient filamentary discharge pulse train appears in the voltage-current waveform, and each filamentary discharge corresponds to a micro-discharge channel, it is determined to be a stable filamentary discharge mode. If the filamentary pulse disappears or uneven discharge occurs, the duty cycle will be automatically adjusted or the excitation mode will be switched to bipolar nanosecond pulse.

10. The nanosecond pulse dielectric barrier discharge ozone generation system with multi-waveform coordinated excitation as described in claim 1, characterized in that, The optimization objectives of the adaptive control module are: ozone generation efficiency greater than or equal to 391.66 g / kWh at 6 kHz frequency, ozone concentration greater than or equal to 12293.59 ppm at 7 kHz frequency, ozone generation efficiency greater than or equal to 160 g / kWh across the entire frequency band, and ozone concentration fluctuation less than or equal to ±3% during 400 minutes of continuous operation.

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